WorldWideScience
 
 
1

Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjornoya (Bear Island) freshwater biota  

Energy Technology Data Exchange (ETDEWEB)

Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjornoya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjoen. In Lake Oyangen, located only 5 km north of Ellasjoen, levels of these contaminants were significantly lower. {delta}{sup 15}N-values were 7-10%o higher in organisms from Ellasjoen as compared to Oyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjoen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. - Elevate levels of chlorobornanes, polychlorinated naphthalenes and brominated flame retardants have been measured in biota from a Norwegian Arctic lake.

Evenset, Anita [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway)]. E-mail: ae@akvaplan.niva.no; Christensen, Guttorm N. [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway); Kallenborn, Roland [Norwegian Institute for Air Research, P.O. Box 100, N-2027 Kjeller (Norway)

2005-08-15

2

Bioaccumulation factors for radionuclides in freshwater biota  

International Nuclear Information System (INIS)

This report analyzes over 200 carefully selected papers to provide concise data sets and methodology for estimation of bioaccumulation factors for tritium and isotopes of strontium, cesium, iodine, manganese, and cobalt in major biotic components of freshwater environments. Bioaccumulation factors of different tissues are distinguished where significant differences occur. Since conditions in the laboratory are often unnatural in terms of chemical and ecological relationships, this review was restricted as far as possible to bioaccumulation factors determined for natural systems. Because bioaccumulation factors were not available for some shorter-lived radionuclides, a methodology for converting bioaccumulation factors of stable isotopes to those of shorter-lived radionuclides was derived and utilized. The bioaccumulation factor for a radionuclide in a given organism or tissue may exhibit wide variations among bodies of water that are related to differences in ambient concentrations of stable-element and carrier-element analogues. To account for these variations, simple models are presented that relate bioaccumulation factors to stable-element and carrier-element concentrations in water. The effects of physicochemical form and other factors in causing deviations from these models are discussed. Bioaccumulation factor data are examined in the context of these models, and bioaccumulation factor relations for the selected radionuclides are presented

1975-01-01

3

Application of the ERICA Assessment Tool to freshwater biota in Finland  

International Nuclear Information System (INIS)

In recent years there has been growing international interest in the assessment of doses and risks from ionising contaminants to biota. In this study the ERICA Tool, developed within the EC 6th Framework Programme, was applied to estimate incremental dose rates to biota in freshwater ecosystems in Finland mainly resulting from exposure to the Chernobyl-derived radionuclides 137Cs, 134Cs and 90Sr. Data sets consisting of measured activity concentrations in fish, aquatic plants, lake water and sediment for three selected lakes located in a region with high 137Cs deposition were applied in the assessment. The dose rates to most species studied were clearly below the screening level of 10 ?Gy h-1, indicating no significant impact of the Chernobyl fallout on these species. However, the possibility of higher dose rates to certain species living on or in the bottom sediment cannot be excluded based on this assessment.

2010-01-01

4

Radionuclide transfer to freshwater biota species: review of Russian language studies  

International Nuclear Information System (INIS)

Around 130 publications reporting studies on radionuclide transfer to freshwater biota species conducted in the former USSR were reviewed to provide the concentration ratio values. None of these studies were available up to now in the English language reviews or publications. The values derived have been compared with the CR values used for freshwater systems in the International reviews. For some radionuclides reviewed in this paper, the data are in good agreement with the mean CR values presented earlier, however for some of them, in particular, for 241Am (bivalve molluscs, gastropods and pelagic fish), 60Co (gastropods, benthic fish and insect larvae), 90Sr and 137Cs (benthic fish and zooplankton), the mean values given here are substantially different from those presented earlier. The data reported in this paper for thirty five radionuclides and eleven groups of freshwater species markedly improve the extent of available data for evaluation of radiation impact on freshwater species. - Research highlights: ? The paper provides information on concentration ratios to freshwater biota species for 35 radionuclides. Many of the data are for 90Sr and 137Cs. ? For the majority of radionuclides reviewed in this paper, the CR values are in good agreement with those given in the recent International reviews. ? For 241Am (bivalve molluscs, gastropods and pelagic fish), 60Co (gastropods, benthic fish and insect larvae), 90Sr and 137Cs (benthic fish and zooplankton), the mean values based on review of the Russian language publications are substantially different from those presented in the International reviews. ? Information presented in the paper significantly increases the availability of data on radionuclide accumulation in freshwater species.

2011-01-01

5

Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment  

International Nuclear Information System (INIS)

The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h-1 (1 rad d-1). A dose rate no greater than 0.4 mGy h-1 to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h-1 will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted

1993-01-01

6

The use of geochemical speciation modelling to predict the impact of uranium to freshwater biota  

International Nuclear Information System (INIS)

Uranium is the prime potential contaminant in mine waste waters that may be released from the Ranger Uranium Mine (RUM) into the receiving waters of the Magela Creek, Alligator Rivers Region, Northern Australia. The potential ecological impact of the migration of uranium, that would result from an elevation in its concentration above background, in the Magela Creek downstream of the RUM, has been experimentally investigated by integrating biomonitoring with geochemical speciation modelling. The freshwater bivalve Velesunio angasi, abundant throughout the Magela Creek catchment, was exposed to a variety of uranium concentrations in a synthetic Magela Creek water, at four pH levels (5.0, 5.3, 5.5 and 6.0), in the presence (3.05 and 7.50 mg l-1) and absence of a model fulvic acid (FA), and its behavioural response was measured. Speciation modelling, using the HARPHRQ code, provided evidence that UO2+2 and UO2OH+ are the uranium species most responsible (ca. 96%) for eliciting an adverse behavioural response when UO2+2 is assigned twice the toxic effect of UO2OH+. This finding rejects the notion that biota respond specifically to the sum total of inorganic uranyl species. (orig.).

1996-01-01

7

PBDEs in marine and freshwater sediments from Belgium: levels, profiles and relations with biota  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sediments from the Belgian North Sea (BNS), the Western Scheldt Estuary (SE) and freshwater watercourses from the Scheldt basin were analysed for eight PBDE congeners, namely BDEs 28, 47, 99, 100, 153, 154, 183 and 209. Previously analysed biological samples from the same locations in the BNS and th...

Voorspoels, S.; Covaci, A.; Maervoet, J.; Schepens, P.

8

An international model validation exercise on radionuclide transfer and doses to freshwater biota  

International Nuclear Information System (INIS)

Under the International Atomic Energy Agency (IAEA)'s EMRAS (Environmental Modelling for Radiation Safety) programme, activity concentrations of 60Co, 90Sr, 137Cs and 3H in Perch Lake at Atomic Energy of Canada Limited's Chalk River Laboratories site were predicted, in freshwater primary producers, invertebrates, fishes, herpetofauna and mammals using eleven modelling approaches. Comparison of predicted radionuclide concentrations in the different species types with measured values highlighted a number of areas where additional work and understanding is required to improve the predictions of radionuclide transfer. For some species, the differences could be explained by ecological factors such as trophic level or the influence of stable analogues. Model predictions were relatively poor for mammalian species and herpetofauna compared with measured values, partly due to a lack of relevant data. In addition, concentration ratios are sometimes under-predicted when derived from experiments performed under controlled laboratory conditions representative of conditions in other water bodies.

2010-01-01

9

Persistent organic pollutants and metals in the freshwater biota of the Canadian Subarctic and Arctic: an overview.  

UK PubMed Central (United Kingdom)

Over 1999-2002, an extensive series of contaminant studies was conducted on freshwater biota of Canada's Arctic and Subarctic regions. The majority of inorganic contaminant studies focused on mercury and fish. While mercury concentrations were low in benthic feeding fish such as whitefish, predatory fish such as lake trout, pike, and walleye frequently had mercury levels which exceeded 0.2 mug/g, the consumption guideline for frequent consumers of fish, and 0.5 microg/g, the guideline for the commercial use of fish. Numerous consumption advisories were issued for lakes along the Mackenzie River. Relatively high mercury levels appear to be due to a combination of relatively old fish populations (because of light fishing pressures) and tend to be more prevalent in smaller lakes where warmer summer water temperatures and watershed influences result in greater mercury and methyl mercury inputs. Mercury levels were substantially lower in char than in lake trout, possibly due to a combination of a less fish-rich diet, a colder environment, and smaller MeHg watershed inputs. Less research has been conducted on other metals but some, such as rubidium, show pronounced variations in concentration that may be related to geological influences. Temporal trend monitoring has revealed little evidence of declining mercury levels in fish that can be attributed to declining atmospheric inputs. Because mercury follows complex pathways in the environment, other factors may operate to counteract reductions in atmospheric mercury sources, e.g., climatic variability, changes in the commercial fishery, and interactions between fish species. Most organochlorine (OC) investigations were based on long term trend monitoring and focused on char (Cornwallis Island), burbot (Great Slave Lake, Yukon lakes, Slave River at Fort Smith, Mackenzie River at Fort Good Hope) and lake trout (Yukon lakes, Great Slave Lake). There was strong evidence of declining OC concentrations in char, particularly SigmaHCH and Sigmachlordane, which may reflect a response to declining atmospheric inputs. Endosulfan concentrations increased, as in the atmosphere. There also was evidence of declining OC concentrations in burbot in the Slave and Mackenzie rivers but not in Great Slave Lake and Yukon lakes. OC concentrations decreased in lake trout in Yukon lakes in the 2000s, most probably because of changes in the fish themselves (i.e., reduced lipid content, condition factor) and possibly climatic variability. Similarly, OCs declined in Great Slave Lake trout. New research on PDBEs and perfluorinated compounds determined that these contaminants are widespread in freshwater fish and concentrations may be increasing. Global warming is a major issue of concern for Arctic and Subarctic waters and may have adverse impacts on contaminant levels in fish and other biota. There is a need for contaminant studies in the north to be broadened to investigate climatic effects. In addition, monitoring studies should be broadened to consider factors affecting other aspects of fish biology. Foremost among these is integrating contaminant monitoring studies on lakes such as Lake Laberge and Great Slave Lake with stock assessment studies. Ecosystem based studies should be conducted on Great Slave Lake and Lake Laberge to more effectively understand contaminant trends and should consider inputs (atmospheric, river inflow, resupension), losses (sedimentation, volatilization), and biological pathways.

Evans MS; Muir D; Lockhart WL; Stern G; Ryan M; Roach P

2005-12-01

10

Technical report series: Concentrations of PCBs, DDTr, and selected metals in biota from Guntersville Reservoir  

Energy Technology Data Exchange (ETDEWEB)

The purpose was to determine if there was potential for human health risks from consumption of reservoir fish or if selected toxic substances might be impacting reservoir biota. Fillets from catfish (channel and blue) and largemouth bass were analyzed for the first purpose and whole gizzard shad, catfish livers, and turtle livers and fat were analyzed for the second. Results indicate largemouth bass should be safe for consumption based on low levels of tested contaminants. However, three of sixteen catfish samples contained PCB levels above the Food and Drug Administration (FDA) tolerance of 2.0 ..mu..g/g, and seven others contained levels sufficiently close to that value to warrant concern. DDT and its metabolites and selected metals were low in catfish except for chromium, nickel, and mercury in selected cases. Analyses on all sample types (those referenced above plus catfish livers and turtle fat and livers) indicated levels of metals were generally low and probably not individually impacting reservoir biota.

Dycus, D.L.; Lowery, D.R.

1986-10-01

11

Polonium-210 and other radionuclides in terrestrial, freshwater and brackish environments Results from the NKS project GAPRAD (Filling knowledge gaps in radiation protection methodologies for non-human biota)  

Energy Technology Data Exchange (ETDEWEB)

The background and rationale to filling knowledge gaps in radiation protection methodologies for biota are presented. Concentrations of Po-210 and Pb-210 are reported for biota sampled in Dovrefjell, Norway and selected lake and brackish ecosystems in Finland. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental studies are recounted. (Author)

Gjelsvik, R.; Brown, J.; Holm, E.; Roos, P.; Saxen, R.; Outola, I.

2012-01-15

12

Polonium-210 and other radionuclides in terrestrial, freshwater and brackish environments Results from the NKS project GAPRAD (Filling knowledge gaps in radiation protection methodologies for non-human biota)  

International Nuclear Information System (INIS)

[en] The background and rationale to filling knowledge gaps in radiation protection methodologies for biota are presented. Concentrations of Po-210 and Pb-210 are reported for biota sampled in Dovrefjell, Norway and selected lake and brackish ecosystems in Finland. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental studies are recounted. (Author)

2012-01-01

13

Selecting reliable and robust freshwater macroalgae for biomass applications.  

Science.gov (United States)

Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m?² day?¹), lowest ash content (3-8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO? across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (±7 S.E.) in Oedogonium-Spirogyra bi-cultures, 86% (±16 S.E.) in Oedogonium-Cladophora bi-cultures and 82% (±18 S.E.) in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demonstrate that freshwater macroalgae are thus far an under-utilised feedstock with much potential for biomass applications. PMID:23717561

Lawton, Rebecca J; de Nys, Rocky; Paul, Nicholas A

2013-05-22

14

Selecting reliable and robust freshwater macroalgae for biomass applications.  

UK PubMed Central (United Kingdom)

Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m?² day?¹), lowest ash content (3-8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO? across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (±7 S.E.) in Oedogonium-Spirogyra bi-cultures, 86% (±16 S.E.) in Oedogonium-Cladophora bi-cultures and 82% (±18 S.E.) in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demonstrate that freshwater macroalgae are thus far an under-utilised feedstock with much potential for biomass applications.

Lawton RJ; de Nys R; Paul NA

2013-01-01

15

Exposure of biota in the cooling pond of Ignalina NPP: hydrophytes  

International Nuclear Information System (INIS)

The radiological assessment of non-human biota is now accepted by a number of international bodies. In this connection the scientific basis to assess and evaluate biota internal and external radiation exposure is required. This paper presents the comparison of freshwater biota (hydrophyte species) exposure due to discharged anthropogenic radionuclides with that due to natural background radiation. The radionuclides from Ignalina Nuclear Power Plant (Lithuania) are discharged into cooling pond - Druksiai Lake. Submerged hydrophytes were selected as biota exposure indicators because they represent the largest biomass in this lake and have comparatively high radionuclide activity concentrations. The detailed methodology evaluation of the submerged hydrophyte dose rate is presented. The ionizing radiation exposure dose rates to submerged hydrophyte roots and above sediment parts due to the major radionuclides (54Mn, 60Co, 137Cs, 90Sr) discharged into the INPP cooling pond - Druksiai Lake were 0.044 ?Gy h-1 and 0.004 ?Gy h-1, respectively. The internal exposure dose rate due to natural background ?-emitters (210Po,238U, 226Ra) was estimated to be 1.24 ?Gy h-1, as compared with that of anthropogenic ?-emitter 240Pu - 0.04 ?Gy h-1, whereas the external exposure was 0.069 ?Gy h-1. The presented data deeper the knowledge about the concentration of radionuclides and submerged hydrophytes' exposure dose rates in European freshwater ecosystems.

2007-01-01

16

Radioprotection of nonhuman biota  

International Nuclear Information System (INIS)

Radioprotection has historically focused on humans with the assumption that human protection confers protection of nonhuman biota. However, there is a need to scientifically and independently demonstrate protection of nonhuman biota. Approaches to address impacts of radiation on nonhuman biota include applying an ecological risk assessment paradigm, setting dose limits, defining reference organisms, and assessing a geographic region. Recommendations include harmonization of a radioprotection framework for both humans and nonhuman biota, a consistent methodology to evaluate radionuclide and nonradionuclide contaminants, a graded assessment approach, development of dosimetric models for reference organisms, compilation of a radiological effects database, and periodic expert review of methodology.

2008-01-01

17

Conserving Madagascar's Freshwater Biodiversity  

Science.gov (United States)

This peer-reviewed article from BioScience is about conserving freshwater diversity in Madagascar. The island nation of Madagascar, an international conservation priority, is now also recognized as a global hotspot for freshwater biodiversity. Three emerging characteristics of Madagascar's threatened freshwater biota deserve increased attention from the scientific and conservation communities. First, species richness is not low, as was once assumed for both the freshwater fishes and the invertebrates. Second, many species are restricted to a specific region or even to single river basins. Often these species are also limited to streams or rivers draining primary forest habitat. Finally, many of the island's freshwater fishes are basal taxa, having diverged earlier than any other extant members of their clade. As such, these taxa assume disproportional phylogenetic importance. In the face of ongoing environmental threats, links among microendemism, forest stream specialization, and basal phylogenetic position highlight the importance and vulnerability of these species and provide a powerful incentive for immediate conservation action.

JONATHAN P. BENSTEAD, PATRICK H. DE RHAM, JEAN-LUC GATTOLLIAT, FRANÃÂOIS-MARIE GIBON, PAUL V. LOISELLE, MICHEL SARTORI, JOHN S. SPARKS, and MELANIE L. J. STIASSNY (;)

2003-11-01

18

The partial monitoring system BIOTA  

International Nuclear Information System (INIS)

The partial monitoring system BIOTA included three sub-systems: - plants; - animals; - biotopes. Monitoring aimed on 19 species of plants and 8 species of animals. All monitored species are classified in Red Red Data List of plants of the Slovak Republic and in Decree No. 24/2003 Coll. Laws, by which is realised the law No. 543/2002 Coll. Laws about the nature and landscape protection. This project comes out from implementation of European agreements and directives into national legislative. The subject of monitoring are selected plant and animal species which are significant from European or national aspect. They are mainly endemic, critically endangered, diminishing and rare species. Also species which are bio-indicating responsible were included into monitoring. From 50 monitored plant and animal species, 45 belong among European significant, included in some of supplements of Directive about birds or Directive about biotopes.

2005-06-09

19

Reanalysis of uranium toxicity data for selected freshwater organisms and the influence of dissolved organic carbon.  

Science.gov (United States)

The present study reanalyzed 46 existing uranium (U) chronic toxicity datasets for four freshwater species to generate consistent toxicity measures and explore relationships between U toxicity and key physicochemical variables. Dissolved organic carbon (DOC) was consistently the best predictor of U toxicity based on 10% inhibitory concentration (IC10) and median inhibitory concentration (IC50) values, with water hardness also being a significant co-predictor of IC50 concentrations for one species. The influence of DOC on acute and chronic U toxicity was further characterized using existing data for five species, and was found to vary depending on species, DOC source, and exposure duration (acute vs chronic). The slopes of the relationships between DOC and (normalized) acute and chronic U toxicity were modeled using cumulative probability distributions. From these, slopes were selected for which to correct acute or chronic U toxicity values or hazard estimates based on the aquatic DOC concentration. The fifth percentiles of these cumulative probability distributions for acute and chronic exposure data were 0.064 and 0.090, respectively, corresponding to a 6.4 and 9.0% reduction in U toxicity relative to the toxicity at the base DOC concentration for each 1 mg/L increase in DOC concentration (over the DOC range 0-30 mg/L). Algorithms were developed to enable the adjustment of U toxicity values and U hazard estimates, depending on DOC concentrations. These algorithms will significantly enhance the environmental relevance of water quality/risk assessments for U in fresh surface waters. PMID:22893585

van Dam, R A; Trenfield, M A; Markich, S J; Harford, A J; Humphrey, C L; Hogan, A C; Stauber, J L

2012-09-07

20

Reanalysis of uranium toxicity data for selected freshwater organisms and the influence of dissolved organic carbon.  

UK PubMed Central (United Kingdom)

The present study reanalyzed 46 existing uranium (U) chronic toxicity datasets for four freshwater species to generate consistent toxicity measures and explore relationships between U toxicity and key physicochemical variables. Dissolved organic carbon (DOC) was consistently the best predictor of U toxicity based on 10% inhibitory concentration (IC10) and median inhibitory concentration (IC50) values, with water hardness also being a significant co-predictor of IC50 concentrations for one species. The influence of DOC on acute and chronic U toxicity was further characterized using existing data for five species, and was found to vary depending on species, DOC source, and exposure duration (acute vs chronic). The slopes of the relationships between DOC and (normalized) acute and chronic U toxicity were modeled using cumulative probability distributions. From these, slopes were selected for which to correct acute or chronic U toxicity values or hazard estimates based on the aquatic DOC concentration. The fifth percentiles of these cumulative probability distributions for acute and chronic exposure data were 0.064 and 0.090, respectively, corresponding to a 6.4 and 9.0% reduction in U toxicity relative to the toxicity at the base DOC concentration for each 1 mg/L increase in DOC concentration (over the DOC range 0-30 mg/L). Algorithms were developed to enable the adjustment of U toxicity values and U hazard estimates, depending on DOC concentrations. These algorithms will significantly enhance the environmental relevance of water quality/risk assessments for U in fresh surface waters.

van Dam RA; Trenfield MA; Markich SJ; Harford AJ; Humphrey CL; Hogan AC; Stauber JL

2012-11-01

 
 
 
 
21

Sources and pathways of selected organochlorine pesticides to the Arctic and the effect of pathway divergence on HCH trends in biota: a review  

International Nuclear Information System (INIS)

[en] Historical global usage and emissions for organochlorine pesticides (OCPs), including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDT), toxaphene and endosulfan, are presented. Relationships between the air concentrations of these OCPs and their global emissions are also discussed. Differences between the pathways of ?- and ?-HCH to the Arctic Ocean are described in the context of environmental concentrating and diluting processes. These concentrating and diluting processes are shown to control the temporal and spatial loading of northern oceans and that the HCH burdens in marine biota from these oceans respond accordingly. The HCHs provide an elegant example of how hemispheric-scale solvent switching processes can alter the ocean into which an HCH congener partitions, how air-water partitioning controls the pathway for HCHs entering the Arctic, and how the various pathways impact spatial and temporal trends of HCH residues in arctic animals feeding out of marine and terrestrial foodwebs

2005-04-15

22

CONCEPTION DES DISPOSITIFS DE FRANCHISSEMENTS POUR LA FAUNE AMPHIDROME (CREVETTES ET POISSONS) DES COURS D'EAU ANTILLAIS : UNE REVUE. CONCEPTION OF PASSAGE FACILITIES FOR THE AMPHIDROMOUS BIOTA (FRESHWATER SHRIMPS AND FISHES) OF THE WEST INDIES : A REVIEW.  

Directory of Open Access Journals (Sweden)

Full Text Available La macrofaune des cours d'eau antillais est constituée principalement d'espèces amphidromes de crevettes d'eau douce (Palaemonidae, Atyidae et Xiphocarididae) et de poissons (Gobiidae). Si la croissance et la reproduction de ces espèces ont lieu en eau douce, le développement larvaire nécessite divers degrés de salinité. La construction de prises d'eau (seuils et barrages collinaires) est susceptible de nuire à la fois aux migrations de dévalaison et aux migrations d'avalaison. Les migrations de dévalaison sont entreprises par les larves nouvellement nées qui sont emportées vers les estuaires par le courant. Les prises d'eau induisent donc des taux élevés de mortalité larvaire par entraînement des larves dans les conduites forcées. Les migrations d'avalaison sont principalement le fait de juvéniles qui présentent un rhéotactisme positif et un potentiel d'escalade des obstacles supérieurs à ceux des adultes. Les ouvrages de faible hauteur réalisés au travers des cours d'eau représentent des obstacles qui sont généralement franchis par escalade. Certains barrages collinaires réalisés aux Antilles ont été équipés de dispositifs de franchissements. Aucun critère biologique n'a cependant été pris en compte pour véritablement faciliter les migrations d'avalaison. En outre les migrations de dévalaison par dérive ont été ignorées. Les exigences d'une libre circulation en relation avec le cycle de vie amphidrome des espèces sont ici rappelées. Les taux élevés de mortalité larvaire peuvent être réduits en évitant les prélèvements d'eau durant les pics maximums de dérive qui ont lieu durant les premières heures après la tombée de la nuit. En cas de prise d'eau en continu des dispositifs lumineux sont susceptibles d'orienter les larves vers les dispositifs délivrant les débits réservés ; ces dispositifs limiteraient ainsi l'entraînement des larves dans les conduites forcées. Limperméabilité des barrages vis-à-vis des migrations d'avalaison peut disparaître complètement lorsque les ouvrages comportent des dispositifs sommaires de franchissements - de types « cascade » ou « passe en écharpe ». Stream macrobiota of the West Indies are dominated by amphidromous species of freshwater shrimps or prawns (Palaemonidae, Atyidae, and Xiphocarididae) and fishes (Gobiidae). if the growth and the reproduction of these species occur in fresh waters, their larval development needs salt water. Weirs and low-head dams for water abstraction may have impacts on both downstream and upstream migrations. Downstream migrations are performed out by newly hatched larvae which are swept by the water flow towards the sea. Water abstraction may induce a high entrainment mortality of larvae. Upstream migrations are carried out mainly by juveniles which present both higher positive rheotactic responses and higher climbing potentialities than adults. Juvenile individuals may have to get over the man-made barriers by climbing. Basic fishways were built on several occasions in the West Indies but no biotic criteria were really taken into account to facilitate the upstream migrations. Moreover the downstream migrations of the larvae were not taken into account. The necessity of maintening a free dam clearing in relation both to the life cycles and to the continuous reproduction of the species is recalled here. The entrainment mortality of larvae can be largely reduced if water is not abstracted during downstream migration which occurs mainly during the first hours after dusk. If water is abstracted continuously, light beams can be used to direct the larvae towards the compensation flows rather than towards the gauged flows. The imperviousnesses of low-head dams to upstream migrants can be eliminated by basic passage facilities such as « cascade-like passes » or « cross-side passes ».

FIÈVET E.; ROUX A. L.; REDAUD L.; SÉRANDOUR J. M.

2009-01-01

23

Evidence for selective bacterial community structuring in the freshwater sponge Ephydatia fluviatilis.  

UK PubMed Central (United Kingdom)

To understand the functioning of sponges, knowledge of the structure of their associated microbial communities is necessary. However, our perception of sponge-associated microbiomes remains mainly restricted to marine ecosystems. Here, we report on the molecular diversity and composition of bacteria in the freshwater sponge Ephydatia fluviatilis inhabiting the artificial lake Vinkeveense Plassen, Utrecht, The Netherlands. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprints revealed that the apparent diversities within the domain Bacteria and the phylum Actinobacteria were lower in E. fluviatilis than in bulk water. Enrichment of specific PCR-DGGE bands in E. fluviatilis was detected. Furthermore, sponge- and bulk water-derived bacterial clone libraries differed with respect to bacterial community composition at the phylum level. E. fluviatilis-derived sequences were affiliated with six recognized phyla, i.e., Proteobacteria, Planctomycetes, Actinobacteria, Bacteroidetes, Chlamydiae and Verrucomicrobia, in order of relative abundance; next to the uncultured candidate phylum TM7 and one deeply rooted bacterial lineage of undefined taxonomy (BLUT). Actinobacteria, Proteobacteria, and Bacteroidetes were the dominant bacterial phyla in the freshwater clone library whereas sequences affiliated with Planctomycetes, Verrucomicrobia, Acidobacteria and Armatimonadetes were found at lower frequencies. Fine-tuned phylogenetic inference showed no or negligible overlaps between the E. fluviatilis and water-derived phylotypes within bacterial taxa such as Alphaproteobacteria, Bacteroidetes and Actinobacteria. We also ascertained the status of two alphaproteobacterial lineages as freshwater sponge-specific phylogenetic clusters, and report on high distinctiveness of other E. fluviatilis specific phylotypes, especially within the Bacteroidetes, Planctomycetes and Chlamydia taxa. This study supports the contention that the composition and diversity of bacteria in E. fluviatilis is partially driven by the host organism.

Costa R; Keller-Costa T; Gomes NC; da Rocha UN; van Overbeek L; van Elsas JD

2013-01-01

24

Accumulation of polychlorinated biphenyls in the freshwater fish, crucian, from the Han river and the Kum river, Korea  

Energy Technology Data Exchange (ETDEWEB)

Even though polychlorinated biphenyls(PCBs) were prohibited from producing and using for a long time, it is still identified in the every environmental media including biota. Since PCBs are lipophilic and persistent, they concentrate readily in the tissue and accumulate exponentially as they move through the food chain. Crucian (Carassius auratus) is most widely living freshwater fish in Korea. So crucian was selected as a representative freshwater fish in this study to determine the accumulation level and distribution characteristics of PCBs. In this study, we attempted to investigate the accumulation profile of individual PCB congeners in the muscle of freshwater fish crucian from the two major rivers, the Han River and Kum River, in Korea.

Jeong, G.H.; Kim, Y.B.; Moon, J.Y.; Lee, S.I.; Kim, H.; Song, H. [Pusan National Univ. (Korea)

2004-09-15

25

Derivation and selection of freshwater sediment quality values in Washington state  

Energy Technology Data Exchange (ETDEWEB)

To derive chemical-based Freshwater Sediment Quality Values (FSQV), bioassay data (Hyalella azteca, Microtox, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia, and Hexagenia limbata) and chemistry data (metals, PAH, pesticide/PCBs, and phenols) were merged from 33 studies and 245 sites in Washington and Oregon into a single database. Apparent Effects Thresholds (AET) and Probable AETs (PAET: 95th percentile of no effects sites) were calculated for Hyalella azteca (n = 228) and Microtox. The efficiency and sensitivity of these values in predicting biological response from chemical concentrations were compared with Ontario`s Severe Effects Level (SEL), Environment Canada`s Probable Effects Level (PEL) and Threshold Effects Level (TEL), EPA`s Equilibrium Partitioning (EQP), and Washington`s marine Sediment management Standards (SMS). For PAH, dry weight normalized values for AETs and PAETs were significantly more sensitive and efficient than organic carbon normalized values. TEL was always the most sensitive and least efficient.

Cubbage, J.; Breidenbach, S.; Batts, D. [Washington Dept. of Ecology, Olympia, WA (United States)

1995-12-31

26

Aquatic ecotoxicity of the selective serotonin reuptake inhibitor sertraline hydrochloride in a battery of freshwater test species.  

UK PubMed Central (United Kingdom)

Sertraline hydrochloride is a selective serotonin reuptake inhibitor (SSRI) widely prescribed to patients suffering from psychiatric disorders. Pharmaceutical products such as sertraline have been identified in environmental waters. This study describes the evaluation of sertraline using a battery of freshwater species representing four trophic levels. The species most sensitive to sertraline were Daphnia magna 21 d reproduction test, Pseudokirchneriella subcapitata 72 h growth inhibition, and Oncorhynchus mykiss 96 h mortality, with the Microtox assay being the least sensitive assay. The D. magna 21 d reproduction test was approximately two orders of magnitude more sensitive than the other bioassays. These results show the advantages of having a tiered approach within a test battery. The presented results indicate that sertraline hydrochloride adversely affects aquatic organisms at levels several orders of magnitude higher than that reported in municipal effluent concentrations, however adverse effects may result from lower concentration exposures, further research into chronic toxicity is therefore advocated.

Minagh E; Hernan R; O'Rourke K; Lyng FM; Davoren M

2009-02-01

27

Stable and selective scintillating anion-exchange sensors for quantification of (99)TcO4(-) in natural freshwaters.  

UK PubMed Central (United Kingdom)

New dual functionality scintillating anion-exchange resins were developed for selective determination of (99)TcO4(-) in various natural freshwater samples. Stable scintillating particles were formed by preparing the vinyl monomer 2-[4-(4'-vinylbiphenylyl)]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (vPBD), starting with the commercial organic flour TBut-PBD and its subsequent copolymerization with styrene, divinylbenzene, and p-chloromethylstyrene mixture. To integrate the radiochemical separation and radiometric detection steps within the same bead, the chloromethyl groups of the scintillating resins were subjected to amination reactions with dioctylamine (DOA) and trioctylamine (TOA). On-line quantification of (99)TcO4(-) was achieved by packing the scintillating anion-exchange resin into Teflon tubing for quantification by a flow scintillation analyzer (FSA). The two functionalized resins were selective for pertechnetate over the common anions in natural freshwaters, especially Cl(-) and SO4(2-) with up to 1000 ppm and with up to 10 ppm I(-) and Cr2O7(2-). The uptake efficiency of the TOA sensor decreased from 97.88% to 85.08% in well water and river water, respectively, while the counting efficiency was almost constant (69.50%). The DOA performance showed lower efficiency in the two water types relative to TOA. On the other hand, the DOA sensor could be regenerated by 5 M HNO3 for reuse at least four times without losing its chemical or optical performance. The detection limit was 1.45 Bq which could be achieved by loading 45 mL from well and tap water containing the maximum contaminant level (MCL) of (99)Tc (33 Bq/L).

Seliman AF; Helariutta K; Wiktorowicz SJ; Tenhu H; Harjula R

2013-09-01

28

Literature review of the concentration ratios of selected radionuclides in freshwater and marine fish  

Energy Technology Data Exchange (ETDEWEB)

Concentration ratios (CR's) used for modeling the uptake and food chain transport of radionuclides in fish have usually been conservative; that is, at the high end of reported values. This practice ensures that the dose to the consumer of contaminated fish will not be underestimated. In many models, however, conservative values have been used for all variables that have any uncertainty associated with them. As a result the dose to the consumer is overestimated. Realistic CR values need to be developed to establish model parameters that will accurately reflect tissue burdens in fish and resulting dose rates to consumers. This report reviews and summarizes published literature on the uptake and distribution of stable and radioactive isotopes of 26 elements. Based on this review, we have made recommendations on CR values to be used for modeling the accumulation of radionuclides in fish. Our recommendations are compared with CR values reported in other publications. A generic discussion of abiotic and biotic factors that influence CR values is provided so that CR values may be adjusted based on site-specific characteristics of the fishes habitat. Recommended CR values for freshwater fish and for marine fish are listed. Although this report emphasizes radionuclides, it is applicable to stable elements as well.

Poston, T.M.; Klopfer, D.C.

1986-09-01

29

Literature review of the concentration ratios of selected radionuclides in freshwater and marine fish  

International Nuclear Information System (INIS)

Concentration ratios (CR's) used for modeling the uptake and food chain transport of radionuclides in fish have usually been conservative; that is, at the high end of reported values. This practice ensures that the dose to the consumer of contaminated fish will not be underestimated. In many models, however, conservative values have been used for all variables that have any uncertainty associated with them. As a result the dose to the consumer is overestimated. Realistic CR values need to be developed to establish model parameters that will accurately reflect tissue burdens in fish and resulting dose rates to consumers. This report reviews and summarizes published literature on the uptake and distribution of stable and radioactive isotopes of 26 elements. Based on this review, we have made recommendations on CR values to be used for modeling the accumulation of radionuclides in fish. Our recommendations are compared with CR values reported in other publications. A generic discussion of abiotic and biotic factors that influence CR values is provided so that CR values may be adjusted based on site-specific characteristics of the fishes habitat. Recommended CR values for freshwater fish and for marine fish are listed. Although this report emphasizes radionuclides, it is applicable to stable elements as well.

1986-01-01

30

Constitution and seed selection method of fresh-water Unio douglasiae family  

UK PubMed Central (United Kingdom)

The invention relates to establishment of a fresh water pearl breeding oyster line and a seed selection method thereof. The method comprises the following steps: 1, selecting non-pearl containing parent oysters with the same age, body length and body height, high vitality, normal body characteristics, and the body weight 15 percent higher than the average body weight, or pearl containing parent oysters with the pearl yield 20 percent higher than the average pearl containing amount from fresh water pearl breeding oysters, and taking the parent oysters as parent oysters for selection with the male and female ratio of 1 to 5:1 and the selection intensity of 0.2 to 20 per mille 2, after the copulation of the parent oysters, separately culturing the filial generations of each line and 3, carrying out the optimization in the four critical fresh water pearl breeding oyster growth periods of an infant oyster period, a child oyster period, an adult oyster period (pearl breeding period) and a prematuration period carrying out the statistics of the indexes of the lines including the average body weight, the body length, the body height, the uniformity, and the like, selecting about 1/3 a line with a high growth rate, a high survival rate and high yield as parent oysters for reservation and repeating the steps1, 2 and 3, and selecting 1 to 7 generations. The method can be used to breed the fresh water pearl breeding oyster lines which have high quality, high and stable yield and strong resistance to diseases and are suitable for the culture environment in our country.

PINHONG YANG

31

Water Quality, Stocking Density and Parasites of Freshwater Fish in Four Selected Areas of Bangladesh  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stocking density, water quality (depth, temperature, dissolved oxygen, pH, total ammonia, hardness as CaCO3 and total alkalinity) and parasites of fishes were investigated in four selected areas (Bogra, Chandpur, Jessore and Mymensingh) for a period of three years. Stocking density varied...

A.N.H. Banu; M.H. Khan

32

Gene flow, recombination, and selection in cyanobacteria: population structure of geographically related Planktothrix freshwater strains.  

UK PubMed Central (United Kingdom)

Several Planktothrix strains, each producing a distinct oligopeptide profile, have been shown to coexist within Lake Steinsfjorden (Norway). Using nonribosomal peptide synthetase (NRPS) genes as markers, it has been shown that the Planktothrix community comprises distinct genetic variants displaying differences in bloom dynamics, suggesting a Planktothrix subpopulation structure. Here, we investigate the Planktothrix variants inhabiting four lakes in southeast of Norway utilizing both NRPS and non-NRPS genes. Phylogenetic analyses showed similar topologies for both NRPS and non-NRPS genes, and the lakes appear to have similar structuring of Planktothrix genetic variants. The structure of distinct variants was also supported by very low genetic diversity within variants compared to the between-variant diversity. Incongruent topologies and split decomposition revealed recombination events between Planktothrix variants. In several strains the gene variants seem to be a result of recombination. Both NRPS and non-NRPS genes are dominated by purifying selection; however, sites subjected to positive selection were also detected. The presence of similar and well-separated Planktothrix variants with low internal genetic diversity indicates gene flow within Planktothrix populations. Further, the low genetic diversity found between lakes (similar range as within lakes) indicates gene flow also between Planktothrix populations and suggests recent, or recurrent, dispersals. Our data also indicate that recombination has resulted in new genetic variants. Stability within variants and the development of new variants are likely to be influenced by selection patterns and within-variant homologous recombination.

Sogge H; Rohrlack T; Rounge TB; Sønstebø JH; Tooming-Klunderud A; Kristensen T; Jakobsen KS

2013-01-01

33

Gene flow, recombination, and selection in cyanobacteria: population structure of geographically related Planktothrix freshwater strains.  

Science.gov (United States)

Several Planktothrix strains, each producing a distinct oligopeptide profile, have been shown to coexist within Lake Steinsfjorden (Norway). Using nonribosomal peptide synthetase (NRPS) genes as markers, it has been shown that the Planktothrix community comprises distinct genetic variants displaying differences in bloom dynamics, suggesting a Planktothrix subpopulation structure. Here, we investigate the Planktothrix variants inhabiting four lakes in southeast of Norway utilizing both NRPS and non-NRPS genes. Phylogenetic analyses showed similar topologies for both NRPS and non-NRPS genes, and the lakes appear to have similar structuring of Planktothrix genetic variants. The structure of distinct variants was also supported by very low genetic diversity within variants compared to the between-variant diversity. Incongruent topologies and split decomposition revealed recombination events between Planktothrix variants. In several strains the gene variants seem to be a result of recombination. Both NRPS and non-NRPS genes are dominated by purifying selection; however, sites subjected to positive selection were also detected. The presence of similar and well-separated Planktothrix variants with low internal genetic diversity indicates gene flow within Planktothrix populations. Further, the low genetic diversity found between lakes (similar range as within lakes) indicates gene flow also between Planktothrix populations and suggests recent, or recurrent, dispersals. Our data also indicate that recombination has resulted in new genetic variants. Stability within variants and the development of new variants are likely to be influenced by selection patterns and within-variant homologous recombination. PMID:23124237

Sogge, Hanne; Rohrlack, Thomas; Rounge, Trine B; Sønstebø, Jørn Henrik; Tooming-Klunderud, Ave; Kristensen, Tom; Jakobsen, Kjetill S

2012-11-02

34

Hydrometeorological variables predict fecal indicator bacteria densities in freshwater: data-driven methods for variable selection.  

UK PubMed Central (United Kingdom)

Statistical models of microbial water quality inform risk management for water recreation. Current research focuses on resource-intensive, location-specific data collection and water quality modeling, but this approach may be cost-prohibitive for risk managers responsible for numerous recreation sites. As an alternative, we tested the ability of two data-driven models, tree regression and random forests with conditional inference trees, to select readily available hydrometeorological variables for use in linear mixed effects (LME) models predicting bacterial density. The study included the Chicago Area Waterway System (CAWS) and Lake Michigan beaches and harbors in Chicago, Illinois, at which Escherichia coli and enterococci were measured seasonally in 2007-2009. Tree regression node variables reduced data dimensionality by >50 %. Variable importance ranks from random forests were used in a forward-step selection based on R (2) and root mean squared prediction error (RMSPE). We found two to three variables explained bacteria densities well relative to random forests with all variables. LME models with tree- or forest-selected variables performed reasonably well (0.335?

Jones RM; Liu L; Dorevitch S

2013-03-01

35

Studies on activity recovery in some mercury-exposed freshwater fish by using selected weeds  

Energy Technology Data Exchange (ETDEWEB)

In spite of worldwide concern about mercury contamination in aquatic environment, relatively little effort has been expended on determining the mechanisms involved in bioaccumulation. It has been found that several species of aquatic plants grow in flowing water of polluted rivers and contain higher mercury levels than the associated water phase. The aquatic weed plants absorb and incorporate the dissolved materials (both inorganic and organic compound) into their own body tissues to rapidly and effectively that they are now considered for use in sewage treatment. The present study evaluated the relative efficiencies of five selected weeds, in mercury toxicity removal suggesting possible methods of mercury removal from contaminated aquatic environments.

Shrivastave, S.; Rao, K.S. (Vikram Univ., Ujjain (India))

1989-06-01

36

Investigation of metal toxicity to tropical biota. Recommendations for revision of Australian water quality guidelines  

International Nuclear Information System (INIS)

The specific objectives of this study were to: review available data on the toxicity of metals to aquatic biota in tropical Australia; identify metals considered to be priority toxicants to aquatic biota in tropical Australia; and employ previously developed toxicity testing protocols for two tropical freshwater species to obtain preliminary toxicity data for two priority metals. From the literature review, it was concluded that insufficient metal toxicity data exist for Australian tropical species. Data were absent for a range of metals (eg Ag, As, Al, Cr, Hg, Ni, Sb and Se) listed in the current Australian water quality guidelines. Aluminium, Cd, Co, Cu, Ni, Mn, Pb, U, V and Zn were identified as priority metals of potential ecotoxicological concern in aquatic ecosystems of tropical Australia, largely as a consequence of mining activities, but also from urban impacts. Instead of testing the toxicity of the priority metals for which data do not currently exist (ie Al, Co, Ni and V), it was deemed more important to conduct further experimental work on Cu and U, in the context of elucidating the relatively high variability in the toxic response of these two metals. As a result, Cu and U were selected and toxicity tests conducted using two tropical freshwater species (green hydra (Hydra viridissima) and gudgeon fish (Mogurnda mogurnda)) from the Australian wet/dry tropics using test protocols designed to maximise the greatest sensitivity of metal response in the shortest period of time. Hydra viridissima was about eight times more sensitive to Cu than U, whereas M. mogurnda was about twenty times more sensitive. Once differences between the sublethal and lethal endpoints of the two organisms were corrected by statistical extrapolation, H. viridissima was approximately seven times more sensitive than M. mogurnda to U, but only about three times more sensitive to Cu. Both species were more sensitive to Cu than U. These results are generally consistent with those from previous studies when differences in key water quality variables, including water hardness, alkalinity, pH and dissolved organic carbon (DOC) are considered.

1997-01-01

37

Antibacterial properties of extracts from selected planktonic freshwater cyanobacteria--a comparative study of bacterial bioassays.  

UK PubMed Central (United Kingdom)

Aqueous and methanol extracts from five selected cyanobacteria were examined for antibacterial properties in six different bacterial bioassays. All five cyanobacteria revealed antibacterial properties. Methanol extracts made from Tychonema bourrellyi, Aphanizomenon flos-aquae and Cylindrospermopsis raciborskii showed the most pronounced inhibitory effects, Aqueous extracts made from Microcystis aeruginosa and T. bourrellyi possessed evident antibacterial properties. The bacterial bioassays were based on agar diffusion tests and included pour-plate methods commonly used to detect residues of antibacterial substances in food. In addition, a pourplate bioassay with Aeromonas hydrophila was developed and described. Antibacterial effects were observed in five of the six bacterial bioassays. No antibacterial effect was observed in the Micrococcus luteus bioassay. Bioassays based on Aer. hydrophila, Bacillus cereus and B. subtilis grown in Antibiotic Medium 8, pH5.85, seemed to be sensitive and suitable. The MIC value of diluted MeOH extracts made from C. raciborskii and T. bourrellyi against Aer. hydrophila corresponded to 38 mg freeze-dried cyanobacteria. Bacillus subtilis was more sensitive when grown in a culture medium with pH 5.85 than 7.9. The antibacterial properties of extracts from the cyanobacteria examined differed from defined cyanotoxins and antibacterial substances. The pattern of inhibition in the bacterial bioassays indicated that various antibacterial substances are involved.

Ostensvik O; Skulberg OM; Underdal B; Hormazabal V

1998-06-01

38

Bioeconomic analysis of selected conservation practices on soil erosion and freshwater fisheries  

Science.gov (United States)

Farmers can generate environmental benefits (improved water quality and fisheries and wildlife habitat), but they may not be able to quantify them. Furthermore, farmers may reduce their incomes from managing lands to produce these positive externalities but receive little monetary compensation in return. This study simulated the relationship between agricultural practices, water quality, fish responses to suspended sediment and farm income within two small watersheds, one of a cool water stream and one of a warm water stream. Using the Agricultural Drainage and Pesticide Transport (ADAPT) model, this study related best management practices (BMPs) to calculated instream suspended sediment concentrations by estimating sediment delivery, runoff, base flow, and streambank erosion to quantify the effects of suspended sediment exposure on fish communities. By implementing selected BMPs in each watershed, annual net farm income declined $18,000 to $28,000 (1 to 3 percent) from previous levels. "Lethal" fish events from suspended sediments in the cool water watershed decreased by 60 percent as conservation tillage and riparian buffers increased. Despite reducing suspended sediments by 25 percent, BMPs in the warm water watershed did not reduce the negative response of the fisheries. Differences in responses (physical and biological) between watersheds highlight potential gains in economic efficiency by targeting BMPs or by offering performance based "green payments." (JAWRA) (Copyright ?? 2005).

Westra, J. V.; Zimmerman, J. K. H.; Vondracek, B.

2005-01-01

39

Proposed Release Guides to Protect Aquatic Biota  

Energy Technology Data Exchange (ETDEWEB)

At the request of South Carolina Department of Health and Environmental Control (SCDHEC) and the Department of Energy (DOE), the Savannah River Laboratory was assigned the task of developing the release guides to protect aquatic biota. A review of aquatic radioecology literature by two leading experts in the field of radioecology concludes that exposure of aquatic biota at one rad per day or less will not produce detectable deleterious effects on aquatic organisms. On the basis of this report, DOE recommends the use of one rad per day as an interim dose standard to protect aquatic biota.

Marter, W.L.

2001-03-28

40

Freshwater Ecosystems  

Science.gov (United States)

In this activity, learners create a freshwater ecosystem in a large plastic bottle. Learners cut and prepare bottles, then fill with water, aquatic plants, snails and fish. Learners observe their mini-ecosystem over time to see what changes--such as the color of the water, the water temperature, plant growth, and behavior and/or population of the snails or fish. The activity serves as a model for larger freshwater ecosystems such as ponds, lakes, rivers, streams, wetlands, reservoirs and groundwater.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

 
 
 
 
41

Acute and sublethal effects of organotin compounds on aquatic biota: an interpretative literature evaluation  

Energy Technology Data Exchange (ETDEWEB)

The objectives of this review were to: (1) collect, synthesize, and interpret acute and sublethal organotin toxicity data in both freshwater and estuarine-marine ecosystems; (2) present environmental water column and sediment concentrations of organotin compounds in both freshwater and estuarine-marine systems to facilitate interpretation of toxicity data; and (3) identify deficiencies in available data to recommend areas of future research for assessing ecological effects of organotin compounds in aquatic systems. The following recommendations are suggested: (1) evaluation of the bioavailability of organotin compounds in aquatic systems; (2) assessment of the relationship between physicochemical characteristics of organotin compounds and subsequent toxicity effects on aquatic organisms; (3) determination of organotin effects on food chains; (4) evaluation of the specific mechanisms and modes of toxicity for organotin compounds with aquatic biotia; (5) evaluations of the adaptive responses of aquatic biota to organotins; (6) measurement of organotin concentrations in testing chambers throughout toxicity tests using peer-reviewed analytical techniques (nominal concentrations can provide misleading data); (7) assessment of long-term ''low level'' exposures of organotin compounds on histological, histochemical, behavioral, and physiological responses of aquatic biota; and (8) toxicity assessment of plasticizer organotin compounds to aquatic biota.101 references.

Hall, L.W. Jr.; Pinkney, A.E.

1985-01-01

42

Assessment of the impact of the Chernobyl Reactor accident on the Biota of Swedeish Streams and Lakes  

International Nuclear Information System (INIS)

The Chernobyl reactor accident resulted in elevated levels of radionuclides in the air space above Sweden, which were then washed into Swedish lakes and streams. Before suspended particles stripped the water column, the concentration of /sp137/Cs in small Swedish lakes was in the order of 10-40 Bq/l. This level of radioactivity should result in a negligible increase in the external exposure rate. However, by August 1986 increased levels of radioactivity were found at all trophic levels of freshwater ecosystems from algae to top carnivore, and from the available data the levels of radioactivity are still increasing. The calculated dose rate for the aquatic biota caused by the two cesium isotopes, /sp134/Cs and /sp137/Cs, is about 25 times higher than natural levels. While acute effectrs of the Chernobyl fallout on freshwater biota are unlikely, the long term ecological effects bear watching.

1986-01-01

43

A method for calculation of dose per unit concentration values for aquatic biota  

International Nuclear Information System (INIS)

A dose per unit concentration database has been generated for application to ecosystem assessments within the FASSET framework. Organisms are represented by ellipsoids of appropriate dimensions, and the proportion of radiation absorbed within the organisms is calculated using a numerical method implemented in a series of spreadsheet-based programs. Energy-dependent absorbed fraction functions have been derived for calculating the total dose per unit concentration of radionuclides present in biota or in the media they inhabit. All radionuclides and reference organism dimensions defined within FASSET for marine and freshwater ecosystems are included. The methodology has been validated against more complex dosimetric models and compared with human dosimetry based on ICRP 72. Ecosystem assessments for aquatic biota within the FASSET framework can now be performed simply, once radionuclide concentrations in target organisms are known, either directly or indirectly by deduction from radionuclide concentrations in the surrounding medium.

2004-12-01

44

Growth responses of selected freshwater algae to trace elements and scrubbed ash slurry generated by coal-fired power plants  

Energy Technology Data Exchange (ETDEWEB)

In laboratory studies, the freshwater algae, Ankistrodesmus falcatus, Scenedesmus obliques, Selenastrum capricornutum and Microcoleus vaginatus were exposed to potential pollutants from coal-fired power plants, and their growth responses were evaluated. Using a modification of the EPA Algae Assay Procedure Bottle Test, algae were incubated in media containing As (V), Cd (II), Hg (II), Se (VI) in solution, and scrubbed ash slurry generated at a western US coal-fired power plants. First significant inhibition levels as well as algistratic- algicidal levels are reported.

Vocke, R.W.

1980-01-01

45

Determination of the 14C activity level in the biota of the surroundings of NPPs  

International Nuclear Information System (INIS)

The results of 14C monitoring in the biota surrounding Czech NPPs (Temelin and Dukovany) are evaluated. The observed levels are compared with those in reference areas. Two types of area with different Suess effect load were selected as reference areas: clear sites ('A'), and sites where a medium local Suess effect is expected ('B'). The local Suess effect in the NPP areas is assumed to lie in between the 2 types of reference area. Statistical evaluation gave evidence of a significantly larger 14C activity in the biota surrounding the two NPPs in comparison with reference area B. The difference of 14C activity between the biota around Temelin and the biota in reference area A was found to be statistically significant and the interval of 14C activity increment could be determined. For Dukovany, only the upper limit of this interval (i.e., in comparison with reference area B) was demonstrable. The results of two linear samplings performed in the vicinity of Dukovany and Paks (Hungary) in 2006 are also outlined and discussed briefly.. The low 14C activity surplus in biota around those NPPs with PWR reactors is due to the low 14CO2 content of the gaseous effluents as compared to other reactor types. Other chemical species with 14C (with prevailing 14CH4) do not contribute to radiocarbon intake by photosynthesis in the surrounding biota. (orig.)

2008-01-01

46

The RESRAD-BIOTA code for application in biota dose assessment  

International Nuclear Information System (INIS)

The RESRAD-BIOTA code was developed through a partnership involving offices of the U.S. Department of Energy, the U.S. Environmental Protection Agency, and the U.S. Nuclear Regulatory Commission. RESRAD-BIOTA is designed to provide a full spectrum of analysis capabilities, from practical conservative screening methods to more realistic organism-specific dose assessments. The RESRAD-BIOTA code has many advanced features such as dose conversion factors for eight ellipsoid organism geometries, sensitivity analysis capability for studying parameter sensitivities, and text and graphic reports for easy interpretation of results. An improved version of the RESRAD-BIOTA code is currently available for test and evaluation. (author)

2003-09-01

47

Temporal trends of Hg in Arctic biota, an update  

DEFF Research Database (Denmark)

A statistically robust method was applied to 83 time-series of mercury in Arctic biota from marine, freshwater and terrestrial ecosystems with the purpose of generating a 'meta-analysis' of temporal trend data collected over the past two to three decades, mostly under the auspices of the Arctic Monitoring and Assessment Program (AMAP). Sampling locations ranged from Alaska in the west to northern Scandinavia in the east. Information from recently published temporal trend studies was tabulated to supplement the results of the statistical analyses. No generally consistent trend was evident across tissues and species from the circumpolar Arctic during the last 30years or so. However, there was a clear west-to-east gradient in the occurrence of recent increasing Hg trends, with larger numbers and a higher proportion of biotic datasets in the Canadian and Greenland region of the Arctic showing significant increases than in the North Atlantic Arctic. Most of the increasing datasets were for marine species, especially marine mammals. A total of 16 (19%) out of the 83 time-series could be classified as "adequate", where adequate is defined as the number of actual monitoring years in a time-series being equal to or greater than the number of years of sampling required to detect a 5% annual change in Hg concentrations, with a significance level of P

Rigét, Frank; Braune, Birgit

2011-01-01

48

Freshwater fish of the Wilderness National Park  

Directory of Open Access Journals (Sweden)

Full Text Available The study aimed to determine the distribution and relative abundance of freshwater fish in the Wilderness National Park. Fish assemblages in the Touw and Duiwe rivers were sampled in 1997 and 1998, with a total of 327 fish from nine species recorded. Indigenous species included two freshwater species (Pseudobarbus afer, Sandelia capensis), two catadromous species (Anguilla mossambicus, Myxus capensis), and two estuarine species (Monodactylusfalciformis, Caffrogobius multifasciatus). Three of the nine recorded species were alien (Micropterus dolomieu, Micropterus salmoides, Gambusia affinis), with the Micropterus spp., in particular, likely to have a substantial negative influence on indigenous species. A further one indigenous species, two translocated indigenous species, and five estuarine species could potentially be recorded in these rivers. River catchment management actions to restore perennial flow to the Duiwe River, to prevent the attenuation of floods, and to prevent further establishment and spread of alien and translocated biota are required to conserve indigenous fish assemblages.

I.A. Russell

1999-01-01

49

Comparative analysis of doses to aquatic biota in water bodies impacted by radioactive contamination.  

UK PubMed Central (United Kingdom)

Comparative analysis of doses to the reference species of freshwater biota was performed for the following water bodies in Russia or former USSR: Chernobyl NPPs cooling pond, Lakes Uruskul and Berdenish located in the Eastern Urals Radioactive Trace, Techa River, Yenisei River. It was concluded that the doses to biota were considerably different in the acute and chronic periods of radioactive contamination. The most vulnerable part of all considered aquatic ecosystems was benthic trophic chain. A numerical scale on the "dose rate - effects" relationships for fish was formulated. Threshold dose rates above which radiation effects can be expected in fish were evaluated to be the following: 1 mGy d(-1) for appearance of the first morbidity effects in fish; 5 mGy d(-1) for the first negative effects on reproduction system; 10 mGy d(-1) for the first effects on life shortening of fish. The results of dose assessment to biota were compared with the scale "dose rate - effects" and the literature data on the radiobiological effects observed in the considered water bodies. It was shown that in the most contaminated water bodies the dose rates were high enough to cause the radiobiological effects in fish.

Kryshev AI; Sazykina TG

2012-06-01

50

Comparative Hydrology, Water Quality, and Ecology of Selected Natural and Augmented Freshwater Wetlands in West-Central Florida  

Science.gov (United States)

Comparing altered wetlands to natural wetlands in the same region improves the ability to interpret the gradual and cumulative effects of human development on freshwater wetlands. Hydrologic differences require explicit attention because they affect nearly all wetland functions and are an overriding influence on other comparisons involving wetland water quality and ecology. This study adopts several new approaches to quantify wetland hydrologic characteristics and then describes and compares the hydrology, water quality, and ecology of 10 isolated freshwater marsh and cypress wetlands in the mantled karst landscape of central Florida. Four of the wetlands are natural, and the other six have water levels indirectly lowered by ground-water withdrawals on municipally owned well fields. For several decades, the water levels in four of these altered wetlands have been raised by adding ground water in a mitigation process called augmentation. The two wetlands left unaugmented were impaired because their water levels were lowered. Multifaceted comparisons between the altered and natural wetlands are used to examine differences between marshes and cypress wetlands and to describe the effects of augmentation practices on the wetland ecosystems. In the karstic geologic setting, both natural and altered wetlands predominantly lost water to the surficial aquifer. Water leaking out of the wetlands created water-table mounds below the wetlands. The smallest mounds radiated only slightly beyond the vegetated area of the wetlands. The largest and steepest mounds occurred below two of the augmented wetlands. There, rapid leakage rates regenerated a largely absent surficial aquifer and mounds encompassed areas 7-8 times as large as the wetlands. Wetland leakage rates, estimated using a daily water-budget analysis applied over multiple years and normalized as inches per day, varied thirtyfold from the slowest leaking natural wetland to the fastest leaking augmented wetland. Leakage rates increased as the size of the flooded area decreased and as the downward head difference between the wetland and the underlying Upper Floridan aquifer increased. Allowing one of the augmented wetlands to dry up for about 2.5 months in the spring of 2004, and then refilling it, generated a net savings of augmentation water despite the amount of water required to recreate the water-table mound beneath the wetland. Runoff from the surrounding uplands was an important component of the water budget in all of the unaugmented wetlands and two of the augmented wetlands. At a minimum, runoff contributed from half (45 percent) to twice (182 percent) as much water as direct rainfall at individual wetlands. Wetland flooded areas, derived using wetland water levels and bathymetric data and presented as a percentage of total wetland area, were used to compare and contrast hydrologic conditions among the 10 wetlands. The percentages of the natural wetland areas that flooded during the study were comparable, despite differences in the sizes of the wetlands. The percent flooded area in each wetland was calculated daily over the study period and monthly for up to 16 years using historical water-level data. Historical flooding in the natural wetlands spanned a greater range in area and had more pronounced seasonality than historical flooding at either the impaired or augmented wetlands. Flooding in the impaired and natural wetlands was similar, however, during 2 years of the study with substantially reduced well-field pumping and above average rainfall. Comparisons indicated several hydrologic differences between the marsh and cypress wetlands in this study. The natural and impaired marshes leaked at about half the rate of the natural and impaired cypress wetlands, and the marshes collectively were underlain by geologic material with lower vertical leakance values than the cypress wetlands. The natural marshes had higher evaporation rates compared to cypress

Lee, T.M.; Haag, K.H.; Metz, P.A.; Sacks, L.A.

2009-01-01

51

Freshwater Flow Charts 1995.  

Science.gov (United States)

This report covers the following: (1) Explanation of Charts Showing Freshwater Flow in 1995; (2) Estimated U.S. Freshwater Flow in 1995 (chart); (3) Estimated California Freshwater Flow in 1995 (chart); (4) Estimated New Mexico Freshwater Flow in 1995 (ch...

G. V. Kaiper

2003-01-01

52

Freshwater Flow Charts - 1995  

Energy Technology Data Exchange (ETDEWEB)

This report covers the following: (1) Explanation of Charts Showing Freshwater Flow in 1995; (2) Estimated U.S. Freshwater Flow in 1995 (chart); (3) Estimated California Freshwater Flow in 1995 (chart); (4) Estimated New Mexico Freshwater Flow in 1995 (chart); and (5) Web locations and credits.

Kaiper, G V

2003-11-21

53

The RESRAD-BIOTA code for application in biota dose evaluation  

International Nuclear Information System (INIS)

The RESRAD-BIOTA code was developed through a partnership among U.S. Department of Energy, the U.S. Environmental Protection Agency, and the U.S. Nuclear Regulatory Commission. RESRAD-BIOTA provides a full spectrum of analysis capabilities, from cost-effective conservative screening methods (using biota concentration guides) to realistic, organism-specific dose assessment. A beta version of the RESRAD-BIOTA code is currently available for use and testing. Continued coordination and partnerships with U.S. agencies and international organizations is providing opportunities for the inclusion of additional evaluation approaches and capabilities, such as (1) development of biota concentration guides for additional radionuclides, (2) additional flexibility for specifying and expanding organism options, (3) improvements to parameter datasets of environmental transfer factors, (4) inclusion of additional ''reference organism geometries'' (e.g., dose conversion factors for ellipsoids of appropriate size and shielding properties for different sized organisms, appropriate for specific ecosystem types), and (5) the capability to perform sensitivity and uncertainty analyses for calculated dose estimates.

2002-01-01

54

U.S. department of energy's graded approach for evaluating radiation doses to aquatic and terrestrial biota  

International Nuclear Information System (INIS)

The United States Department of Energy (DOE) has been active in the development of requirements, methods and guidance for protection of the environment (biota and ecosystems) from the effects of ionising radiation since the late 1980's. This oral presentation provided an overview of: (1) DOE's requirements and strategic objectives for the evaluation of doses to biota at DOE sites and facilities; (2) a practical screening tool provided within DOE's graded approach to biota dose evaluation; (3) lessons learned from the first year of the graded approach methodology's implementation at DOE sites; and (4) thoughts for International Commission on Radiological Protection (ICRP) activities on radiological protection of the environment. Practical and cost-effective methods are needed for demonstrating protection of biota. Through its Biota Dose Assessment Committee (BDAC), the DOE has developed screening methods, models, and guidance within a graded approach for evaluating radiation impacts to biota (Figure 1). DOE's graded approach is described in the DOE Technical Standard, 'A Graded Approach for Evaluating Radiation Doses to Aquatic and Terrestrial Biota'. A series of electronic spread-sheets for conducting an evaluation are contained in a 'RAD-BCG Calculator'.' A practical screening methodology provides limiting concentrations of radionuclides, termed Biota Concentration Guides (BCGs), for use in screening water, sediment, and soil media to determine if dose limits for biota might be exceeded. Methods and models for site-specific screening and detailed analysis, if needed, are also provided (Table 1). Four reference organisms were selected as the basis for methods development. Internal and external exposure assumptions and default parameters used provide for conservative screening values. Users can modify the biota dose limits and parameter values to account for site-specific receptors and exposure scenarios. DOE's proactive outreach and co-ordination with other U.S. agencies (through the Interagency Steering Committee on Radiation Standards) and with international organisations has resulted in opportunities for partnerships and methods advancement. DOE's approach for evaluating radiation doses to biota is proving useful as a sensible and cost-effective tool that could be employed within an overall framework for protection of the environment from the effects of ionising radiation. (author)

2002-01-01

55

Preliminary study on radiological impact assessment of radioactive liquid effluent to aquatic biota  

International Nuclear Information System (INIS)

RESRAD-BIOTA is a computer code recommended by U.S. Department of Energy (DOE) for assessing the radiological close of aquatic biota. RESRAD-BIOTA code is briefly introduced, and an example is given. The existing problems, further improvement and research directions of RESRAD-BIOTA code applied to radiological impact of aquatic biota are pointed out in the end. (authors)

2008-01-01

56

Scoping assessment of groundwater doses to biota at the Sellafield site, UK  

International Nuclear Information System (INIS)

In the current climate of investigating the impact of discharges from the nuclear industry on non-human biota, much attention has been given to biota in marine and terrestrial environments in receipt of authorised discharges of liquid and gaseous effluent. Relatively little attention to date has been given to the exposure of biota to groundwater containing man-made radio-nuclides. This area of interest is growing especially in the field of nuclear waste repositories. A scoping assessment has been performed here to determine the impacts due to radiological contamination on organisms living within or coming into contact with groundwater at the Sellafield site, UK. The following potential exposure routes to biota were identified: 1) Organisms living within groundwater; 2) Groundwater discharges to the surface at beach springs (i.e. emerging above the low water line; 3) Groundwater discharges to nearby surface water bodies (e.g. rivers); 4) Groundwater discharges directly to the Irish Sea.. In order to evaluate impacts on organisms living within, contacting or ingesting groundwater, it was necessary to determine the activity concentration of radio-nuclides in the groundwater. For time periods up to 2120, modeling of contaminant release from in-ground inventories and transport in groundwater was carried out for this scoping study using a relatively simple assessment methodology with the MONDRIAN modeling suite. Screening assessments of radiological impacts upon wildlife have been performed for liquid discharges to groundwater from the Sellafield Ltd reprocessing plant at Sellafield, Cumbria. Impacts have been considered for biota at sites within reach of the groundwater flow network. Most calculated total weighted absorbed doses appear to be of no radiological significance whatsoever in relation to the new Environment Agency freshwater ecosystem trigger level (40 microGy h-1), thereby obviating the need to conduct further investigations. The one exception to this is for bacteria at groundwater site 205 (107 microGy h-1 in 2060 and 66.8 microGy h-1 in 2080), although this is believed to be inconsequential due to the very small size of bacteria. In addition, the maximum dose rate criteria recommended by the IAEA (400 microGy h-1) is not exceeded for any of the species of interest at any of the locations studied (author)(tk)

2008-01-01

57

Interactions of radionuclides with marine biota  

International Nuclear Information System (INIS)

Uptake of radioactivity by marine biota can occur through consumption of radioactive food or via direct incorporation from the seawater. As uptake occurs, radioactivity begins to distribute into and onto various body tissues, or ''compartments'', at different rates. A composite uptake curve therefore is curvilinear with time. Elimination can occur via various pathways, including fecal deposition, molting, and excretion of dissolved substances, and therefore a composite loss curve also is curvilinear. Uptake and elimination can occur simultaneously, and under constant conditions over a long time period a steady-state body burden will be achieved. Many factors can affect uptake and loss rates, as well as steady-state body burdens, and some major ones are discussed. Design of radioactivity experiments involving marine biota is explored, and a case study of a ''natural experiment'' involving both reactor-produced and fallout radionuclides in a coastal environment is presented to show how much nuclide introductions can be used to learn about nuclide biomagnification, trophic level relationships, and biological distribution of radioactivity in the sea. (author)

1997-01-01

58

Derivation of a screening methodology for evaluating radiation dose to aquatic and terrestrial biota  

International Nuclear Information System (INIS)

The United States Department of Energy (DOE) currently has in place a radiation dose standard for the protection of aquatic animals, and is considering additional dose standards for terrestrial biota. These standards are: 10 mGy/d for aquatic animals, 10 mGy/d for terrestrial plants, and, mGy/d for terrestrial animals. Guidance on suitable approaches to the implementation of these standards is needed. A screening methodology, developed through DOE's Biota Dose Assessment Committee (BDAC), serves as the principal element of DOE's graded approach for evaluating radiation doses to aquatic and terrestrial biota. Limiting concentrations of radionuclides in water, soil, and sediment were derived for 23 radionuclides. Four organism types (aquatic animals; riparian animals; terrestrial animals; and terrestrial plants) were selected as the basis for development of the screening method. Internal doses for each organism type were calculated as the product of contaminant concentration, bioaccumulation factor(s) and dose conversion factors. External doses were calculated based on the assumption of immersion of the organism in soil, sediment, or water. The assumptions and default parameters used provide for conservative screening values. The screening methodology within DOE's graded approach should prove useful in demonstrating compliance with biota dose limits and for conducting screening assessments of radioecological impact. It provides a needed evaluation tool that can be employed within a framework for protection of the environment.

2003-01-01

59

The uptake of radiationless by some fresh water aquatic biota review  

International Nuclear Information System (INIS)

[en] The work presented in this paper reviews many studies carried out by the authors along the last thirty years. The behaviour of the radionuclides in the aquatic ecology of Ismailia Canal stream is of great interest for the evaluation of the possible hazards that may occur to man through the movement of such radionuclides via food chain. Laboratory investigations have been carried out in order to understand the accumulation and release of some radionuclide by some aquatic biota (aquatic macrophyte aquatic plants, some snails species and some fish species) inhabiting this fresh water stream. Different parameters such as water ph, contact time, water salinity, etc. were used in these investigations. The kinetic analysis of the uptake process of some radio nuclides by certain biota was performed. From this analysis, it was possible (through the statistical methods) to investigate that the uptake process proceeded through different steps with different rates depending on the radionuclide and the biota species. It was possible to conclude that some of the selected biota can be used as biological indicators for certain radionuclides

2005-01-01

60

Arsenic contamination in the freshwater fish ponds of Pearl River Delta: bioaccumulation and health risk assessment.  

UK PubMed Central (United Kingdom)

This study investigated the extent of arsenic (As) contamination in five common species of freshwater fish (northern snakehead [Channa argus], mandrarin fish [Siniperca chuatsi], largemouth bass [Lepomis macrochirous], bighead carp [Aristichthys nobilis] and grass carp [Ctenopharyngodon idellus]) and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The total As concentrations detected in fish muscle and sediment in freshwater ponds around the PRD were 0.05-3.01 mg kg(-1) wet weight (w. wt) and 8.41-22.76 mg kg(-1) dry weight (d. wt), respectively. In addition, the As content was positively correlated (p < 0.05) to total organic carbon (TOC) contents in sediments. Biota sediment accumulation factor (BSAF) showed that omnivorous fish and zooplankton accumulated higher concentrations of heavy metals from the sediment than carnivorous fish. In addition, feeding habits of fish also influence As accumulation in different fish species. In this study, two typical food chains of the aquaculture ponds were selected for investigation: (1) omnivorous food chain (zooplankton, grass carp and bighead carp) and (2) predatory food chain (zooplankton, mud carp and mandarin fish). Significant linear relationships were obtained between log As and ? (15)N. The slope of the regression (-0.066 and -0.078) of the log transformed As concentrations and ? (15)N values, as biomagnifications power, indicated there was no magnification or diminution of As from lower trophic levels (zooplankton) to fish in the aquaculture ponds. Consumption of largemouth bass, northern snakehead and bighead carp might impose health risks of Hong Kong residents consuming these fish to the local population, due to the fact that its cancer risk (CR) value exceeded the upper limit of the acceptable risk levels (10(-4)) stipulated by the USEPA.

Cheng Z; Chen KC; Li KB; Nie XP; Wu SC; Wong CK; Wong MH

2013-07-01

 
 
 
 
61

Water hardness reduces the accumulation and toxicity of uranium in a freshwater macrophyte (Ceratophyllum demersum).  

UK PubMed Central (United Kingdom)

There is a lack of good quality data and mechanistic understanding on the effects of true water hardness (calcium (Ca) and magnesium (Mg)) on the bioavailability and toxicity of uranium (U) to freshwater biota. This study determined the effect of true water hardness (20, 75, 150, 275 and 400 mg CaCO(3) L(-1)) on the cell surface binding affinity (log K), accumulation and toxicity (growth inhibition) of U in a submerged, rootless, macrophyte (Ceratophyllum demersum) in a synthetic freshwater with constant alkalinity (13 mg CaCO(3) L(-1)) and pH (6.2) over 7 days. A 20-fold increase in water hardness resulted in a 4-fold decrease in U toxicity (median effect concentration (EC50)=134 ?g L(-1)U at 20 mg CaCO(3 )L(-1) hardness, increasing to 547 ?g L(-1) U at 400 mg CaCO(3) L(-1) hardness), cell surface binding affinity (log K=6.25 at 20 mg CaCO(3) L(-1) hardness, decreasing to log K=5.64 at 400 mg CaCO(3) L(-1) hardness) and accumulation (the concentration factor decreased from 63 at 20 mg CaCO(3) L(-1) hardness to 15 at 400 mg CaCO(3) L(-1) hardness) of U. Calcium provided a 4-fold greater protective effect against U accumulation and toxicity compared to Mg. Speciation calculations indicated negligible differences in the percentages of key U species (UO(2)(2+), UO(2)OH(+), UO(2)(OH)(2)) over the range of water hardness tested. The inhibition of U binding at the cell surface, and subsequent uptake, by C. demersum, with increasing Ca and/or Mg concentration, may be explained in terms of (i) competition between Ca(2+)/Mg(2+) and UO(2)(2+) (and/or UO(2)OH(+)) for physiologically active sites at the cell surface, and/or (ii) reduced negative charge (electrical potential) at the cell surface, resulting in a decrease in the activity of UO(2)(2+) (and/or UO(2)OH(+)) at the plant/water interface (boundary layer), and consequently, less U bound to physiologically active cell surface sites. In the absence of a biotic ligand model for U, the results of this study (together with previous work) reinforce the need for a more flexible, hardness-dependent, U guideline for the protection of selected freshwater biota.

Markich SJ

2013-01-01

62

A method for calculation of dose per unit concentration values for aquatic biota within FASSET  

International Nuclear Information System (INIS)

A dose per unit concentration database has been generated for application to ecosystem assessments within the FASSET framework. Organisms are represented by ellipsoids of appropriate dimensions, and the proportion of radiation absorbed within the organisms is calculated using a numerical method implemented in a series of spreadsheet-based programs. Energy-dependent absorbed fraction functions were derived for calculating the total dose per unit concentration of radionuclides present in biota or their surrounding medium. All radionuclides and reference organism dimensions defined within FASSET for marine and freshwater ecosystems are included. With regard to the applicability of the method, it is assumed that differences in density between the organism and the surrounding environmental media may be ignored; for the aquatic environment this is an extremely good approximation. (author)

2003-09-01

63

Recent changes in aquatic biota in subarctic Fennoscandia - the role of global and local environmental variables  

Science.gov (United States)

The Arctic, representing a fifth of the earth's surface, is highly sensitive to the predicted future warming and it has indeed been warming up faster than most other regions. This makes the region critically important and highlights the need to investigate the earliest signals of global warming and its impacts on the arctic and subarctic aquatic ecosystems and their biota. It has been demonstrated that many Arctic freshwater ecosystems have already experienced dramatic and unpreceded regime shifts during the last ca. 150 years, primarily driven by climate warming. However, despite the indisputable impact of climate-related variables on freshwater ecosystems other, especially local-scale catchment related variables (e.g. geology, vegetation, human activities) may override the climate signal and become the primary factor in shaping the structure of aquatic ecosystems. Although many studies have contributed to an improved understanding of limnological and hydrobiological features of Artic and subarctic lakes, much information is still needed especially on the interaction between the biotic and abiotic components, i.e. on factors controlling the food web dynamics in these sensitive aquatic ecosystems. This is of special importance as these lakes are of great value in water storage, flood prevention, and maintenance of biodiversity, in addition to which they are vital resources for settlement patterns, food production, recreation, and tourism. In this study we compare the pre-industrial sediment assemblages of primary producers (diatoms and Pediastrum) and primary consumers (cladoceran and chironomids) with their modern assemblages (a top-bottom approach) from 50 subarctic Fennoscandian lakes. We will evaluate the recent regional pattern of changes in aquatic assemblages, and assess how coherent the lakes' responses are across the subarctic area. Moreover, the impact of global (e.g. climate, precipitation) and local (e.g. lake and its catchment characteristics) scale environmental changes on the aquatic biota will be compared and discussed.

Weckström, Jan; Leppänen, Jaakko; Sorvari, Sanna; Kaukolehto, Marjut; Weckström, Kaarina; Korhola, Atte

2013-04-01

64

User's guide, version 1 RESRAD-BIOTA : a tool for implementing a graded approach to biota dose evaluation  

International Nuclear Information System (INIS)

This Interagency Steering Committee on Radiation Standards (ISCORS) Technical Report provides a User's Guide for the RESRAD-BIOTA code. The RESRAD-BIOTA code is a tool for implementing a graded approach to biota dose evaluation. The RESRAD-BIOTA code was principally sponsored and developed by the U.S. Department of Energy (DOE), with support from the U.S. Environmental Protection Agency (EPA) and the U.S. Nuclear Regulatory Commission (NRC), through the informal interagency Ecological Radiological Work Group (ECORAD-WG). The work group was led by DOE and coordinated under the oversight of ISCORS. The RESRAD-BIOTA code provides a complete spectrum of biota dose evaluation capabilities, from methods for general screening, to comprehensive receptor-specific dose estimation. The code was designed to be consistent with and provide a tool for implementing the DOE ''Graded Approach for Evaluating Radiation Doses to Aquatic and Terrestrial Biota'' (DOE voluntary consensus Technical Standard DOE-STD-1153-2002), and to provide advanced analysis capabilities in a manner that will support the anticipated needs of DOE and other agencies. These advanced analysis capabilities were generally developed through a consensus-based process among the participating agency representatives of the ECORAD-WG.

2004-01-01

65

Choosing an alpha radiation weighting factor for doses to non-human biota  

International Nuclear Information System (INIS)

The risk to non-human biota from exposure to ionizing radiation is of current international interest. In calculating radiation doses to humans, it is common to multiply the absorbed dose by a factor to account for the relative biological effectiveness (RBE) of the radiation type. However, there is no international consensus on the appropriate value of such a factor for weighting doses to non-human biota. This paper summarizes our review of the literature on experimentally determined RBEs for internally deposited alpha-emitting radionuclides. The relevancy of each experimental result in selecting a radiation weighting factor for doses from alpha particles in biota was judged on the basis of criteria established a priori. We recommend a nominal alpha radiation weighting factor of 5 for population-relevant deterministic and stochastic endpoints, but to reflect the limitations in the experimental data, uncertainty ranges of 1-10 and 1-20 were selected for population-relevant deterministic and stochastic endpoints, respectively.

1116-01-00

66

Freshwater Ulva (Chlorophyta) as a bioaccumulator of selected heavy metals (Cd, Ni and Pb) and alkaline earth metals (Ca and Mg).  

UK PubMed Central (United Kingdom)

We analyzed the ability of freshwater taxa of the genus Ulva (Ulvaceae, Chlorophyta) to serve as bioindicators of metal in lakes and rivers. Changes in heavy metal (Ni, Cd and Pb) and alkaline earth metal (Ca and Mg) concentrations in freshwater Ulva thalli were investigated during the period from June to August 2010. The study was conducted in two ecosystems in Western Poland, the Malta lake (10 sites) and the Nielba river (six sites). Three components were collected for each sample, including water, sediment and Ulva thalli. The average concentrations of metals in the water sample and in the macroalgae decreased in the following order: Ca>Mg>Ni>Pb>Cd. The sediment revealed a slightly altered order: Ca>Mg>Pb>Ni>Cd. Ca and Mg were found at the highest concentrations in thalli due to the presence of carbonate on its surface. Among the examined heavy metals in thalli, Ni was in the highest concentration, and Cd found in the lowest concentration. There were statistically significant correlations between the levels of metals in macroalgae, water and sediment. Freshwater populations of Ulva exhibited a greater efficiency to bioaccumulate nickel as compared to species derived from marine ecosystems.

Rybak A; Messyasz B; ??ska B

2012-11-01

67

Effects of thermal discharges on aquatic biota  

International Nuclear Information System (INIS)

The primary objective of this research is to determine the effect of sudden thermal stress on the exercise physiology of rainbow trout. Metabolic activity of fish is influenced by many factors. Two of the most important are temperature and exercise. The experiments reported here are designed to assess the simultaneous interactions of these two environmental features. In these studies, the tolerance of the fish to thermal stress is evaluated by measuring the blood glucose levels. Fish respond to environmental stress by exhibiting an elevation of the blood sugar level. The metabolic effects of exercise are determined by measuring the production of lactic acid in muscle tissue and determining the level of this metabolite in the circulating blood. Bioassays involving gradual and abrupt cold shock are required for development of criteria applicable to assessment of potential impact on biota inhabiting mixing zones following termination of heated discharges. Thermal conditions in such areas are highly variable. Any detrimental effect is related to such features as original acclimation temperature and resistance to cold of the different species involved, as well as temperature decline rates, prevailing minimum temperatures, and durations of exposure to that minimum

1976-01-01

68

Central Northwest Pacific biota and their radioactivity  

International Nuclear Information System (INIS)

Ecological and radiological surveys of biota around a proposed dumping site have been carried out by the Japanese Fisheries Agency. Micronekton were collected with a KOC net towed at prescribed depths. Fish nekton were collected with a KMT net towed from 1 to 2 hours either obliquely or horizontally at prescribed depths. This large net enabled the collection of larger organisms not collectable with KOC nets. Benthos were collected via benthos nets. Deep sea rattails and gammarids were collected with trapnets. In 1985, larger gear with mouth diameters of 1.8m were used with older gear having mouth diameters of 0.9m and used previously. New large gear allowed better collecting efficiency. Radioactivity measurements were carried out by gammaspectrometry with GeLi detectors on ashed samples. In almost all samples, Cs-137 was detected. In addition Co-60 was detected in some samples. Data obtained by the Tokai Regional Fisheries Research Laboratory were examined and summarized by the Ecology Working Group under the Executive Committee on Environmental Safety Assessment of Sea Dumping of Low level Radioactive Wastes in the Radioactive Waste Management Center

1989-01-01

69

Effect of chronic selenium exposure on the freshwater bivalve Corbicula fluminea  

International Nuclear Information System (INIS)

[en] Selenium is essential for most of living organisms. In oxic to moderately oxic fresh-waters, Se exists predominantly in the (+VI) and (+IV) oxidation states as selenate (SeO42-) and selenite (SeO32-) respectively, whereas in the biota it is incorporated as Se(-II) into seleno-proteins or amino-acids, or as elemental selenium Se(0). At low concentrations, it acts against oxidative damages mainly as the glutathione peroxidase seleno-dependant, but it may be toxic at higher levels (for example, by replacing sulphur in important biomolecules). In filter feeders, such as the freshwater bivalve Corbicula fluminea, selected as biological model, the ventilation activity is a primary limiting step that controls the water influx and therefore the delivery of contaminants. Consequently, a series of short-term experiments were performed to study the effects of different dissolved Se concentrations and forms (selenite; selenate; selenomethionine) on the ventilation activity of Corbicula fluminea and Se tissular distribution. The modification of the ventilation activity of the Se-exposed groups, in comparison to this of reference groups (not exposed to Se) varied greatly according to the form and the concentrations of the Se used. Se concentrations in tissues indicated that selenite was the less bioavailable form whereas selenomethionine displayed the opposite trend. On the basis of this set of experiments, a limited number of conditions have been selected to provide highly contrasting ventilation flow rates and selenium bioaccumulation levels, in order to study the effects of long term exposures, i) at the molecular level, by measuring bio-markers of oxidative stress (forms of glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, and bio-marker of genotoxicity (comet assay), ii) at the (sub)cellular level by analysing Se micro-localisation in target organs and iii) at the individual level by monitoring the variation in the ventilatory flow rate. (author)

2004-01-01

70

Effect of chronic selenium exposure on the freshwater bivalve Corbicula fluminea  

Energy Technology Data Exchange (ETDEWEB)

Selenium is essential for most of living organisms. In oxic to moderately oxic fresh-waters, Se exists predominantly in the (+VI) and (+IV) oxidation states as selenate (SeO{sub 4}{sup 2-}) and selenite (SeO{sub 3}{sup 2-}) respectively, whereas in the biota it is incorporated as Se(-II) into seleno-proteins or amino-acids, or as elemental selenium Se(0). At low concentrations, it acts against oxidative damages mainly as the glutathione peroxidase seleno-dependant, but it may be toxic at higher levels (for example, by replacing sulphur in important biomolecules). In filter feeders, such as the freshwater bivalve Corbicula fluminea, selected as biological model, the ventilation activity is a primary limiting step that controls the water influx and therefore the delivery of contaminants. Consequently, a series of short-term experiments were performed to study the effects of different dissolved Se concentrations and forms (selenite; selenate; selenomethionine) on the ventilation activity of Corbicula fluminea and Se tissular distribution. The modification of the ventilation activity of the Se-exposed groups, in comparison to this of reference groups (not exposed to Se) varied greatly according to the form and the concentrations of the Se used. Se concentrations in tissues indicated that selenite was the less bioavailable form whereas selenomethionine displayed the opposite trend. On the basis of this set of experiments, a limited number of conditions have been selected to provide highly contrasting ventilation flow rates and selenium bioaccumulation levels, in order to study the effects of long term exposures, i) at the molecular level, by measuring bio-markers of oxidative stress (forms of glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, and bio-marker of genotoxicity (comet assay), ii) at the (sub)cellular level by analysing Se micro-localisation in target organs and iii) at the individual level by monitoring the variation in the ventilatory flow rate. (author)

Fournier, E.; Adam, C.; Massabuau, J.C.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

2004-07-01

71

Overview of the EMRAS biota dosimetry working group  

International Nuclear Information System (INIS)

Current principle of radiation protection systems is protection of human, because the human is assumed as the most sensitive organism. Protection framework of human is also believed to be effective for protection of non-human species. On the other hand, it is recently attracting the international interests how sustainability of the ecological services is influenced by environmental disturbances such as chemicals and radiation. Therefore, international concern about protection framework of nonhuman biota has arisen. By the international concern, European and American countries were respectively developed models to evaluate effects of radiation to biota. However, the models are based on their own assumptions, so that the international validity has not been confirmed. Therefore, in IAEA, biota dosimetry working group (BWG) was established in Environmental Modeling for Radiation Safety (EMRAS) program, which aimed to intercompare the models to validate their assumptions and estimations. This paper reports summary of the activity in EMRAS biota dosimetry working group. (author)

2008-01-01

72

GROUP REPORT: INTERACTIONS AMONG ACIDIFICATION, PHOSPHOROUS, CONTAMINANTS, AND BIOTA IN FRESHWATER ECOSYSTEMS  

Science.gov (United States)

Scientific investigations over the last two decades have examined the processes and effects of acidic deposition on surface waters and their catchments. hese studies have been performed on various scales: laboratory benchtop, mesocosm/plot studies, whole system manipulations, and...

73

The U.S. Department of Energy's graded approach for evaluating radiation doses to non-human biota  

International Nuclear Information System (INIS)

The United States Department of Energy (DOE) has been active in developing requirements, methods, and guidance for protection of non-human biota from the effects of ionizing radiation since the late 1980's. Radiation protection of the environment is an emerging issue that will likely require attention in environmental monitoring programs, and in decisions regarding cleanup and long-term stewardship of radioactively-contaminated sites. The DOE currently has a radiation dose limit for protecting aquatic organisms, and has considered dose limits for terrestrial biota. Practical, cost-effective guidance for implementation of these dose rate guidelines are needed. In response, DOE has developed methods, models, and guidance within a graded approach for evaluating radiation doses to non-human biota. The methodology was developed using an interdisciplinary team approach that included both 'developers' and 'users' through DOE's Biota Dose Assessment Committee (BDAC). The first phase of the graded or multi-tiered approach consists of a general screening methodology that provides limiting concentrations of radionuclides, termed Biota Concentration Guides (BCGs), for use in screening water, sediment, and soil to determine if dose guidelines for non-human biota are exceeded. BCGs were derived for twenty-three target radionuclides. Four organism types (aquatic animals, riparian animals, terrestrial animals, and terrestrial plants) were selected as the basis for methods development. Internal doses were calculated as the product of media concentration, bioaccumulation factor(s), and dose conversion factors. External doses were calculated based on the assumption of immersion of the organism in soil, sediment, or water. Kinetic and allometric techniques were used to fill data gaps in predicting radionuclide concentration factors across a large range of terrestrial and riparian species of animals. The assumptions and default parameters result in conservative BCGs for screening purposes. If the BCGs are exceeded, methods for site-specific screening, followed by detailed analysis, are also provided. A user-selected dose standard can be entered in place of default dose guidelines; parameter values, radiation weighting factors, and organism residence times can be modified within site-specific phases of the graded approach. A recent effort by DOE to encode the graded approach methodology into the 'next generation' biota dose evaluation tool, 'RESRAD-BIOTA', is near completion. The RESRAD-BIOTA computer code provides complete analysis capabilities, from general screening to more realistic organism-specific dose estimation. The RESRAD-BIOTA code contains many advanced features such as: dose conversion factors for eight ellipsoid organism geometries; sensitivity analysis; and text and graphic reports for easy interpretation of results. DOE's graded approach to non-human biota dose evaluation is being widely implemented at DOE's facilities. The graded approach is a cost-effective tool for demonstrating compliance with dose limits for non-human biota, and for conducting ecological screening assessments. In can be employed within an international framework for radiation protection of the environment. (author)

2004-01-01

74

Approaches to estimating the transfer of radionuclides to arctic biota  

Energy Technology Data Exchange (ETDEWEB)

There is increasing concern over potential radioactive contamination of the Arctic due to the wide range of nuclear sources. Environmental characteristics of the Arctic also suggest that it may be comparatively vulnerable to contaminants. Here we review collated data and available models for estimating the transfer of radionuclides to terrestrial biota within the Arctic. The most abundant data are for radiocaesium and radiostrontium although many data for natural radionuclides were available from studies in the Arctic. For some radionuclides no data are available for describing transfer to Arctic biota. Allometric-kinetic models have been used to provide estimates of transfer for radionuclide biota combinations for which data were lacking. Predicted values were in good agreement with observed data for some radionuclides (e.g. Cs, U) although less so for others. However, for some radionuclides where comparison appeared poor there were relatively little observed data with which to compare and the models developed were simplistic excluding some potentially important transfer pathways (e.g. soil ingestion). There are no bespoke models to enable the dynamic prediction of radionuclide transfer to Arctic biota. A human food chain model is available which includes limited parameterization for Cs and Sr transfer in Arctic ecosystems. This has been relatively easily adapted to estimate {sup 137}Cs and {sup 90}Sr transfer to some Arctic biota and could be readily adapted to other radionuclide-biota combinations. There are many factors of Arctic ecosystems which may influence radionuclide behaviour including short growing seasons, prolonged freezing of soil, and effects of low temperatures on biological rates. However, these are not included within existing predictive models (for human or biota exposure). If exposure to ionising radiation within Arctic ecosystems is to be robustly predicted such factors must be fully understood and properly incorporated into models. (author)

Beresford, N.A.; Wright, S.M.; Barnett, C.L.; Golikov, V.; Shutov, V.; Kravtsova, O. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Bailrigg, Lancaster (United Kingdom)

2004-07-01

75

Pollution due to volatile halocarbon compounds in biota  

Energy Technology Data Exchange (ETDEWEB)

In recent years, volatile halocarbon compounds (VHCs) in drinking water have elicited increasing social concern and health problems. Further, it was reported that carcinogenic and/or mutagenic effects have been induced in animals by several VHCs. These substances were also detected in biota, sediment, and human food. Several methods were developed for the determination of VHCs in these types of samples. In each case, VHCs were eventually measured by gas chromatography. One of the pretreatment techniques involves the fairly simple procedure where samples are extracted with isooctane and subsequently isolated by micro florisil column. However, this method is susceptible to low recovery. Ferrario et al. (1985) reported that ecosystems in Lake Pontchartrain were polluted based on the fact that VHCs were detected by the purge and trap method, using a pretreatment method slightly different from the ones mentioned above. Nevertheless, no report about an evaluation of the amount of pollutants in biota as human food was found. In this report, the substantially improved Daft method for VHC analysis was applied to environmental biota and sediments, and an attempt was made to clarify the cause of pollution due to VHCs in biota. Furthermore, we found several interesting phenomena concerning the movement of VHCs in biota. 8 refs., 1 fig., 3 tabs.

Gotoh, Masayuki (Ube College (Japan)); Sekitani, Yoshiko; Aramaki, Teruyo; Kobayashi, Haruo; Ogino, Keiki; Hobara, Tatsuya (Yamaguchi Univ. School of Medicine, Ube (Japan))

1992-08-01

76

Plutonium in biota from an east Tennessee floodplain forest  

International Nuclear Information System (INIS)

239 240Pu concentrations were measured in biota from a 30-year-old contaminated floodplain forest in Tennessee. Concentration ratios relative to soil, for plutonium in litter, invertebrate cryptozoans, herbaceous ground vegetation, orthoptera and small mammals were approximately 10-1, 10-2, 10-3, and 10-4, respectively. Concentration ratios (CR) for plutonium in biota from the floodplain forest are less than CR values from other contaminated ecosystems in the USA. Presumably, this is due to humid conditions and greater rainfall which minimize resuspension as a physical transport mechanism to biota. Plutonium and radiocesium concentrations are correlated in biota from the forest at Oak Ridge and also from Mortandad Canyon in New Mexico. The cause of the covariance between concentrations of these elements is unknown. Nevertheless, the existence of these relationships suggests that it is possible to predict plutonium in biota from radiocesium concentrations when both nuclides have a common origin and occur together in a contaminated terrestrial environment. (author)

1978-01-01

77

Simulation of potential oyster density with variable freshwater inflow (1965-2000) to the caloosahatchee river estuary, southwest Florida, USA.  

UK PubMed Central (United Kingdom)

Oyster beds are disappearing worldwide through a combination of over-harvesting, diseases, and salinity alterations in the coastal zone. Sensitivity of oysters to variable discharge and salinity is particularly acute in small sub-tropical estuaries subject to regulated freshwater releases. South Florida has sub-tropical estuaries where watershed flood control sometimes results in excessive freshwater inflow to estuaries during the wet season (May-Oct) and reduced discharge and increased salinities in the dry season (Nov-Apr). The potential to reserve freshwater accumulated during the wet season could offer the capacity to regulate freshwater at different temporal scales, thus optimizing salinity conditions for estuarine biota. The goal of this study was to use simulation modeling to explore the effects of freshwater inflows and salinity on adult oyster survival in the Caloosahatchee River Estuary (CRE) in southwest Florida. Water managers derived three different freshwater inflow scenarios for the CRE based on historical and modified watershed attributes for the time period of 1965-2000. Three different salinity time series were generated from the inflow scenarios at each of three sites in the lower CRE and used to conduct nine different oyster simulations. Overall, the predicted densities of adult oysters in the upstream site were 3-4 times greater in seasons that experienced reduced freshwater inflow (e.g., increased salinity) with oyster density in the lower estuary much less influenced by the inflows. Potential storage of freshwater reduced the frequency of extreme flows in the wet season and helped to maintain minimum inflow in the dry season near the estuarine mouth. Analyses of inflows indicated that discharges ranging from 0 to 1,500 cfs could promote favorable salinities of 10-25 in the lower CRE depending on wet versus dry season climatic conditions. This range of inflows is similar to that derived in other studies of the CRE and emphasizes the value of simulation models to help prescribe freshwater releases which benefit estuarine biota.

Buzzelli C; Doering PH; Wan Y; Gorman P; Volety A

2013-10-01

78

Simulation of Potential Oyster Density with Variable Freshwater Inflow (1965-2000) to the Caloosahatchee River Estuary, Southwest Florida, USA  

Science.gov (United States)

Oyster beds are disappearing worldwide through a combination of over-harvesting, diseases, and salinity alterations in the coastal zone. Sensitivity of oysters to variable discharge and salinity is particularly acute in small sub-tropical estuaries subject to regulated freshwater releases. South Florida has sub-tropical estuaries where watershed flood control sometimes results in excessive freshwater inflow to estuaries during the wet season (May-Oct) and reduced discharge and increased salinities in the dry season (Nov-Apr). The potential to reserve freshwater accumulated during the wet season could offer the capacity to regulate freshwater at different temporal scales, thus optimizing salinity conditions for estuarine biota. The goal of this study was to use simulation modeling to explore the effects of freshwater inflows and salinity on adult oyster survival in the Caloosahatchee River Estuary (CRE) in southwest Florida. Water managers derived three different freshwater inflow scenarios for the CRE based on historical and modified watershed attributes for the time period of 1965-2000. Three different salinity time series were generated from the inflow scenarios at each of three sites in the lower CRE and used to conduct nine different oyster simulations. Overall, the predicted densities of adult oysters in the upstream site were 3-4 times greater in seasons that experienced reduced freshwater inflow (e.g., increased salinity) with oyster density in the lower estuary much less influenced by the inflows. Potential storage of freshwater reduced the frequency of extreme flows in the wet season and helped to maintain minimum inflow in the dry season near the estuarine mouth. Analyses of inflows indicated that discharges ranging from 0 to 1,500 cfs could promote favorable salinities of 10-25 in the lower CRE depending on wet versus dry season climatic conditions. This range of inflows is similar to that derived in other studies of the CRE and emphasizes the value of simulation models to help prescribe freshwater releases which benefit estuarine biota.

Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Gorman, Patricia; Volety, Aswani

2013-10-01

79

Ecodosimetry weighting factor (eR) for non-human biota  

International Nuclear Information System (INIS)

The ICRP's radiological protection guidance for humans recognizes that equal absorbed doses of different types of radiation can have different biological effects in humans. ICRP publication 60 thus prescribes radiation weighting factors, wR values, to modify the absorbed dose (Gy) to effective dose (Sv) to enable the risk from different types of radiation to be compared on an equivalent basis. The wR values are selected on the basis of various considerations, including the linear energy transfer of the radiation and relative biological effectiveness (RBE) values (which are the ratios of the absorbed dose of reference to test radiation that produce an equivalent level of effect, for a given endpoint, system and dose level). There is no similar factor for non-human biota. It would be useful to have one: assessment of possible impacts on non-human biota (particularly from alpha-emitters and tritium beta-rays) is important for Canadian nuclear facilities. We propose a radiation equivalency factor 'eR' for biota to fulfill a role equivalent to that occupied by wR in human radiation protection. RBE values for deterministic effects such as reproduction, fecundity and survival in biota are the critical bases for selection of eR values. These deterministic effects in populations are far more relevant to the assessment endpoints in ecological risk assessment than are stochastic effects, to which RBE values in human radiation protection relate. For tritium ?-rays, most determinations support RBE values of 2-3 for deterministic effects when referenced to gamma radiation but little more than unity when x-rays are the reference radiation. This is because x-rays themselves have RBE -2 if referenced to gamma rays. Despite this, the ICRP assigns a wR of 1 to all electrons and all photons, including tritium beta-rays. Therefore, if eR is constrained to an integer, 1 is more appropriate than a value of 2 for tritium beta-rays. An RBE factor of 200-300 for alpha particles in radiation protection of non-human biota has been suggested in Canada, but in two studies that reported RBE values of about 250, the dosimetry for alpha particles was uncertain. Furthermore, RBE value of 20 for non-human biota is indefensible because it relates to stochastic effects in individuals. For deterministic effects, most animal studies report RBE values (for population-based endpoints) in the range of 5-10. Since ecological risk to biota generally appears only when doses are moderately high, the most logical and reasonable choice of eR for ?-emitters is not the larger, limiting value of RBE value observed at low doses, but rather a value around 5. (author)

2000-01-01

80

Radioactive radium and lead isotopes determinations in biota samples  

International Nuclear Information System (INIS)

210Pb and radium's isotopes were determined in biota samples by two different radiochemical techniques-Fe(OH)3 co-precipitation and calcium phosphate precipitation. The applied procedures were adapted for very small amount (0.25 g) of sample material and were checked in actual biota samples. Measurements were made by liquid scintillation counting, ?- and ?-spectrometry. All the results show that Ca3(PO4)2 precipitation technique is better for determination of trace radionuclide concentrations in biota. The procedure of separation is stable with significant yield for the both 210Pb and radium's isotopes and can be successfully used for assessment of environmental stressors in field of bio-monitoring. (author)

2009-01-01

 
 
 
 
81

Functionally and phylogenetically diverse plant communities key to soil biota.  

UK PubMed Central (United Kingdom)

Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity--ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset of a grassland biodiversity experiment. Plant functional and phylogenetic diversity were generally better predictors of soil biota than the traditionally used species or functional group richness. Functional diversity was a reliable predictor for most biota, with the exception of soil microorganisms, which were better predicted by phylogenetic diversity. These results provide empirical support for the idea that the diversity of plant functional traits and the diversity of evolutionary lineages in a community are important for maintaining higher abundances and diversity of soil communities.

Milcu A; Allan E; Roscher C; Jenkins T; Meyer ST; Flynn D; Bessler H; Buscot F; Engels C; Gubsch M; König S; Lipowsky A; Loranger J; Renker C; Scherber C; Schmid B; Thébault E; Wubet T; Weisser WW; Scheu S; Eisenhauer N

2013-08-01

82

Mercury in freshwater systems  

Energy Technology Data Exchange (ETDEWEB)

The report summarizes the experiences of mercury in freshwater systems, including transportation and cycling of mercury, alkylation of mercury, mercury in aquatic organisms, predicting and modelling biomagnification of mercury, toxicity of mercury and possibilities of restoring mercury contaminated waters.

Jerneloev, A.; Martin, A.L.

1980-03-01

83

Artificial radionuclides in aquatic biota of major european rivers  

International Nuclear Information System (INIS)

Studies on the content of radionuclides in water, suspended particles, bed sediment and aquatic biota of different trophic levels relate to different periods and regions and suggest that our knowledge of the radiological situation in Europe's largest rivers varies considerably. Radioactive contamination of the Danube has been studied in greatest detail -a corollary of the intensive development of nuclear energy and of international interest in radioecological problems in this region. Here we present the results of studies of Sr-90 and Cs-137 - the ecologically most significant artificial radionuclides - in aquatic biota of different trophic levels in the Volga, Danube and Dnieper. The studies were carried out in 1988. (author).

1991-01-01

84

Global satellite monitoring of spatial and temporal changes of biota  

Energy Technology Data Exchange (ETDEWEB)

Various aspects of the study of global changes of biota are examined. It is suggested that such changes can be effectively studied by combining satellite observations with ground measurements and theoretical investigations. The basic requirements concerning satellite-borne scientific payloads and observing strategies are discussed. 42 refs.

Izakov, M.N.; Zhukov, B.S. (RAN, Inst. Kosmicheskikh Issledovanii, Moscow (Russian Federation))

1992-12-01

85

Comparative toxicity of single and combined mixtures of selected pollutants among larval stages of the native freshwater mussels (Unio elongatulus) and the invasive zebra mussel (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

This study evaluated the impact of biocides (tributyltin, chlorthalonil and Irgarol 1051) and of pollutants (copper, inorganic and methyl mercury and 4-nonylphenol) occurring in Ebro River (NE Spain) on early developmental stages of native Spanish freshwater and invasive zebra mussels. Toxicity tests were conducted with embryos and glochidia of zebra mussel (Dreissena polymorpha) and the naiad species Unio elongatulus, respectively. Toxicity was quantified in terms of median effective concentration (EC50) impairing embryogenesis and glochidia viability in single and combined mixture exposures. Irgarol 1051 was not toxic at concentrations below 40x10(3)nM. Zebra mussel embryos were on average 50 fold more sensitive to the studied pollutants than glochidia. Tributyltin was the most toxic compound with EC50s for zebra mussel embryos and glochidia, respectively, of 1.24 and 47.93 nM, followed by chlorothalonil (3.65, 176.58 nM), methyl mercury (7.06, 156.4 nM), inorganic mercury (3.64, 518.28 nM), copper (19.73, 1358.55 nM) and 4-nonylphenol (33.99, 1221.48 nM). Combined toxicity of Ebro River pollutants (copper, inorganic and methyl mercury and 4-nonylphenol) was greater than additive in zebra mussel embryos and additive in glochidia. These results indicated that contaminant levels that affect zebra mussel embryos are not toxic to early life stages of the naiad mussel species U. elongatulus.

Faria M; López MA; Fernández-Sanjuan M; Lacorte S; Barata C

2010-05-01

86

Assessment of doses to biota in the river system  

Energy Technology Data Exchange (ETDEWEB)

Doses to aquatic biota in the hydrological system Techa - Ob are estimated.The following water bodies with different levels of radioactive contamination are considered: industrial reservoirs, Techa, Iset, Tobol and Irtysh Rivers. Doses to biota are calculated using the observed data on the content of radionuclides in various ennmental components, with consideration for geometric characteristics of the organisms and the exposure sources. The following groups of the river biota are considered: aquatic plants, mollusks and fish. Simplified geometric models (ellipsoids) are used in the internal dose calculations for fish and mollusks. Aquatic plants are approximated either with spheres or with a layer of finite depth. For the external doses assessment the water was considered as an infinite source with the uniform distribution of radionuclides. Sediments were represented as a source with the uniformly distributed activity. Concentration factor of scattered radiation was taken into account for gamma emitters. Sources and levels of radioactive contamination of the Techa - Ob system are analyzed. Data on the activity concentration of radionuclides in water, bottom sediments and aquatic biota are used for the dose assessment. Assessment of doses to biota in the Techa -Ob river system in the period from 1949 to the present time are performed.The highest doses (over 0.01 Gy/day) were received by aquatic organisms in the upper reaches of the Techa River in the period of maximum discharges of radionuclides (1950-1951). In that period, a major contribution to the dose to aquatic organisms was due to the incorporated radionuclides: 89 Sr, 90 Sr, 106 Ru,137 Cs, 144 Ce and others. During 1950-1951, the doses to aquatic organisms were estimated, on average, at 0.003-0.1 Gy/day. After the cessation of intensive radioactive discharges and the construction of a system of protective water bodies, the doses to aquatic biota noticeably decreased. Current levels of exposure to fish in the Techa River are estimated as 3 x 10-4 Gy/day in the upper reaches of Techa River, 6 x 10-6 Gy/day in the Techa River mouth, 9 x 10-7 Gy/day in the Iset River, 10-7 Gy/day in the Tobol River and 6 x 10-8 Gy/day in the Irtysh River; the major contributors to the doses are 90 Sr and 137 Cs. It is shown that exposure to aquatic biota noticeably decreased with distance frhe site of discharges. (authors)

Kryshev, I.; Kryshev, A.; Sazykina, T. [SPA ' Typhoon' , Obninsk (Russian Federation)

2006-07-01

87

Origin and behaviour of radiocaesium, plutonium and americium in the sediment-water-biota system of Strangford Lough  

International Nuclear Information System (INIS)

Strangford Lough, located on the NE coast of Ireland, is a marine nature reserve of considerable ecological importance. Here, we report selected features from a recent (September 1997) detailed study of the radioecological status of the lough, including the spatial distribution of radionuclides in sea water, sediment and biota within the lough, the chemical speciation of Pu in lough waters and measured Pu concentrations through the narrows at ebb and flood tide

1999-01-01

88

Freshwater and fish  

International Nuclear Information System (INIS)

Severe radioactive contamination of the freshwater environment could have serious consequences for both drinking water and fish. Most of the Nordic countries have an abundance of freshwater lakes and rivers. Finland alone has about 56,000 lakes, each with a surface area of 1 hectare or more. Nearly 10% of Finland's surface is covered with lakes and rivers. In Sweden, about 9% of the surface area is freshwater, in Norway about 5%, and in Denmark only about 2%. Freshwater plays a minor role in Iceland, but even there numerous rivers discharge from the volcanic soils to the Ocean. Cs-137 and 90Sr are likely to be the most important radionuclides with respect to long term radioactive contamination of freshwater. If radioactive deposition occurs in the absence of snow and ice radionuclides will contaminate the surface water directly and may rapidly enter the aquatic food chain. Fish which eat contaminated plankton become contaminated almost immediately. Deposition during summer increases the transfer for radionuclides to fish since fish metabolism is faster during the warm season. During the cold period, fish metabolism is slow and thus uptake and excretion of radiocaesium are also slow. (EG).

1997-01-01

89

Freshwater and fish  

Energy Technology Data Exchange (ETDEWEB)

Severe radioactive contamination of the freshwater environment could have serious consequences for both drinking water and fish. Most of the Nordic countries have an abundance of freshwater lakes and rivers. Finland alone has about 56,000 lakes, each with a surface area of 1 hectare or more. Nearly 10% of Finland`s surface is covered with lakes and rivers. In Sweden, about 9% of the surface area is freshwater, in Norway about 5%, and in Denmark only about 2%. Freshwater plays a minor role in Iceland, but even there numerous rivers discharge from the volcanic soils to the Ocean. Cs-137 and {sup 90}Sr are likely to be the most important radionuclides with respect to long term radioactive contamination of freshwater. If radioactive deposition occurs in the absence of snow and ice radionuclides will contaminate the surface water directly and may rapidly enter the aquatic food chain. Fish which eat contaminated plankton become contaminated almost immediately. Deposition during summer increases the transfer for radionuclides to fish since fish metabolism is faster during the warm season. During the cold period, fish metabolism is slow and thus uptake and excretion of radiocaesium are also slow. (EG). 18 refs.

Saxen, R. [Finnish Centre for Radiation and Nuclear Safety (Finland)

1997-10-01

90

PBDEs in freshwater mussels and fish from Flanders, Belgium  

Energy Technology Data Exchange (ETDEWEB)

Polybrominated diphenylethers (PBDEs), a class of brominated flame retardants (BFRs), are widely used in textiles, plastics, electronic equipment and other materials for more than 30 years. Due to their massive use, PBDEs have become ubiquitously present in aquatic organisms and it was recently evidenced that their levels seem to increase rapidly. Higher PBDE concentrations were found in biota from freshwater compared to similar marine species. This is probably due to a higher pollution load found near point pollution sources that are almost exclusively inland located. Zebra mussels (Dreissena polymorpha) fulfil the requirements of a good biomonitoring organism for freshwater ecosystems: they are easy to collect and to handle, are available in sufficient numbers, have a relative long lifespan, are sedentary and resistant to various types of pollution without suffering a too high mortality and have a high filtration rate which favours the bioaccumulation of organic contaminants. Fish species are another suitable tool for the biomonitoring of organic contaminants. The occurrence of PBDEs in fish species from Europe has already received some attention, but the amount of data is still limited. The aim of this study was to evaluate the occurence of PBDEs in zebra mussels and several representative freshwater fish species (eel, carp and gibel carp) at different sites in Flanders, Belgium. In parallel, other organohalogenated contaminants, such as polychlorinated biphenyls (PCBs), p,p'-DDE and hexachlorobenzene (HCB) were also measured and their relationship with PBDEs was investigated.

Covaci, A.; Voorspoels, S.; Schepens, P. [Antwerp Univ. (Belgium). Toxicological Center; Bervoets, L.; Hoff, P.; Voets, J.; Campenhout, K. van; Blust, R. [Antwerp Univ. (Belgium). Dept. of Ecophysiology, Biochemistry and Toxicology

2004-09-15

91

Comparison of dose estimate results from radioecological risk assessment models RESRAD-BIOTA, ERICA Tool and SENES Risk Model using a case study  

Energy Technology Data Exchange (ETDEWEB)

There are many software programs designed to estimate the risk to non-human biota from exposure to radioactivity. Three models have been selected for comparison in this study: US DOE RESRAD-BIOTA Model, EC ERICA Tool and SENES Risk Model. It appears that the methodology for these models is similar, whereas the parameters used to model a case study are different, creating different outputs. Issues surrounding combined or 'lumped' parameters were identified with implications on the transparency and uncertainty of results. These issues are explored so that they may be avoided by choosing the appropriate model and implementation for a given scenario. (author)

Garisto, N.; Kovacs, R.; Janes, A. [SENES Consultants Limited, Richmond Hill, Ontario (Canada)

2010-07-01

92

Derivation of transfer parameters for use within the ERICA Tool and the default concentration ratios for terrestrial biota  

International Nuclear Information System (INIS)

An ability to predict radionuclide activity concentrations in biota is a requirement of any method assessing the exposure of biota to ionising radiation. Within the ERICA Tool fresh weight whole-body activity concentrations in organisms are estimated using concentration ratios (the ratio of the activity concentration in the organism to the activity concentration in an environmental media). This paper describes the methodology used to derive the default terrestrial ecosystem concentration ratio database available within the ERICA Tool and provides details of the provenance of each value for terrestrial reference organisms. As the ERICA Tool considers 13 terrestrial reference organisms and the radioisotopes of 31 elements, a total of 403 concentration ratios were required for terrestrial reference organisms. Of these, 129 could be derived from literature review. The approaches taken for selecting the remaining values are described. These included, for example, assuming values for similar reference organisms and/or biogeochemically similar elements, and various simple modelling approaches.

2008-01-01

93

Derivation of transfer parameters for use within the ERICA Tool and the default concentration ratios for terrestrial biota  

Energy Technology Data Exchange (ETDEWEB)

An ability to predict radionuclide activity concentrations in biota is a requirement of any method assessing the exposure of biota to ionising radiation. Within the ERICA Tool fresh weight whole-body activity concentrations in organisms are estimated using concentration ratios (the ratio of the activity concentration in the organism to the activity concentration in an environmental media). This paper describes the methodology used to derive the default terrestrial ecosystem concentration ratio database available within the ERICA Tool and provides details of the provenance of each value for terrestrial reference organisms. As the ERICA Tool considers 13 terrestrial reference organisms and the radioisotopes of 31 elements, a total of 403 concentration ratios were required for terrestrial reference organisms. Of these, 129 could be derived from literature review. The approaches taken for selecting the remaining values are described. These included, for example, assuming values for similar reference organisms and/or biogeochemically similar elements, and various simple modelling approaches.

Beresford, N.A. [Centre for Ecology and Hydrology, CEH-Lancaster, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)], E-mail: nab@ceh.ac.uk; Barnett, C.L.; Howard, B.J.; Scott, W.A. [Centre for Ecology and Hydrology, CEH-Lancaster, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Brown, J.E. [Norwegian Radiation Protection Authority, Department of Emergency Preparedness and Environmental Radioactivity, Grini naeringspark 13, Post Box 55, NO-1332 Osteras (Norway); Copplestone, D. [Environment Agency, Richard Fairclough House, Knutsford Road, Warrington, Cheshire WA4 1HG (United Kingdom)

2008-09-15

94

Trout Farming in Freshwater  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Trout farming, the business of producing and selling high quality rainbow trout, has been expanding rapidly in the last 5 years. There are now some 20 freshwater farms in operation producing over 500 tonnes per annum. Initially some farms were operated as part of an integrated agricultural farm acti...

Doyle, J

95

What are the toxicological effects of mercury in Arctic biota?  

DEFF Research Database (Denmark)

This review critically evaluates the available mercury (Hg) data in Arctic marine biota and the Inuit population against toxicity threshold values. In particular marine top predators exhibit concentrations of mercury in their tissues and organs that are believed to exceed thresholds for biological effects. Species whose concentrations exceed threshold values include the polar bears (Ursus maritimus), beluga whale (Delphinapterus leucas), pilot whale (Globicephala melas), hooded seal (Cystophora cristata), a few seabird species, and landlocked Arctic char (Salvelinus alpinus). Toothed whales appear to be one of the most vulnerable groups, with high concentrations of mercury recorded in brain tissue with associated signs of neurochemical effects. Evidence of increasing concentrations in mercury in some biota in Arctic Canada and Greenland is therefore a concern with respect to ecosystem health.

Dietz, Rune; Sonne, Christian

2013-01-01

96

What are the toxicological effects of mercury in Arctic biota?  

Science.gov (United States)

This review critically evaluates the available mercury (Hg) data in Arctic marine biota and the Inuit population against toxicity threshold values. In particular marine top predators exhibit concentrations of mercury in their tissues and organs that are believed to exceed thresholds for biological effects. Species whose concentrations exceed threshold values include the polar bears (Ursus maritimus), beluga whale (Delphinapterus leucas), pilot whale (Globicephala melas), hooded seal (Cystophora cristata), a few seabird species, and landlocked Arctic char (Salvelinus alpinus). Toothed whales appear to be one of the most vulnerable groups, with high concentrations of mercury recorded in brain tissue with associated signs of neurochemical effects. Evidence of increasing concentrations in mercury in some biota in Arctic Canada and Greenland is therefore a concern with respect to ecosystem health. PMID:23231888

Dietz, Rune; Sonne, Christian; Basu, Niladri; Braune, Birgit; O'Hara, Todd; Letcher, Robert J; Scheuhammer, Tony; Andersen, Magnus; Andreasen, Claus; Andriashek, Dennis; Asmund, Gert; Aubail, Aurore; Baagøe, Hans; Born, Erik W; Chan, Hing M; Derocher, Andrew E; Grandjean, Philippe; Knott, Katrina; Kirkegaard, Maja; Krey, Anke; Lunn, Nick; Messier, Francoise; Obbard, Marty; Olsen, Morten T; Ostertag, Sonja; Peacock, Elizabeth; Renzoni, Aristeo; Rigét, Frank F; Skaare, Janneche Utne; Stern, Gary; Stirling, Ian; Taylor, Mitch; Wiig, Øystein; Wilson, Simon; Aars, Jon

2012-12-08

97

Filling knowledge gaps in radiation protection methodologies for non-human biota. Final summary report  

Energy Technology Data Exchange (ETDEWEB)

The activities of the GAPRAD project are summarised in this report. The background and rationale to GAPRAD are presented and explained. Most notably this relates to a lack of information on naturally occuring radionuclides in terrestrial and aquatic systems that have direct applicability for use in environmental impact assessments. Results from field activities are presented from the Dovrefjell area in Norway (terrestrial study) and selected lake and brackish water systems in Finland. The data mainly concern activity concentrations of Po-210 in environmental media and selected biota allowing concentration ratios to be derived where appropriate. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental work conducted within the project are presented. (au)

Brown, J.; Gjelsvik, R. (Norwegian Radiation Protection Authority (Norway)); Holm, E. (Univ. of Lund (Sweden)); Roos, P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Saxen, R.; Outola, I. (Radiation and Nuclear Safety Authority (Finland))

2009-03-15

98

Filling knowledge gaps in radiation protection methodologies for non-human biota. Final summary report  

International Nuclear Information System (INIS)

The activities of the GAPRAD project are summarised in this report. The background and rationale to GAPRAD are presented and explained. Most notably this relates to a lack of information on naturally occuring radionuclides in terrestrial and aquatic systems that have direct applicability for use in environmental impact assessments. Results from field activities are presented from the Dovrefjell area in Norway (terrestrial study) and selected lake and brackish water systems in Finland. The data mainly concern activity concentrations of Po-210 in environmental media and selected biota allowing concentration ratios to be derived where appropriate. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental work conducted within the project are presented. (au)

2009-01-01

99

Soil biota reduce allelopathic effects of the invasive Eupatorium adenophorum.  

Science.gov (United States)

Allelopathy has been hypothesized to play a role in exotic plant invasions, and study of this process can improve our understanding of how direct and indirect plant interactions influence plant community organization and ecosystem functioning. However, allelopathic effects can be highly conditional. For example allelopathic effects demonstrated in vivo can be difficult to demonstrate in field soils. Here we tested phytotoxicity of Eupatorium adenophorum (croftonweed), one of the most destructive exotic species in China, to a native plant species Brassica rapa both in sand and in native soil. Our results suggested that natural soils from different invaded habitats alleviated or eliminated the efficacy of potential allelochemicals relative to sand cultures. When that soil is sterilized, the allelopathic effects returned; suggesting that soil biota were responsible for the reduced phytotoxicity in natural soils. Neither of the two allelopathic compounds (9-Oxo-10,11-dehydroageraphorone and 9b-Hydroxyageraphorone) of E. adenophorum could be found in natural soils infested by the invader, and when those compounds were added to the soils as leachates, they showed substantial degradation after 24 hours in natural soils but not in sand. Our findings emphasize that soil biota can reduce the allelopathic effects of invaders on other plants, and therefore can reduce community invasibility. These results also suggest that soil biota may have stronger or weaker effects on allelopathic interactions depending on how allelochemicals are delivered. PMID:21980442

Zhu, Xunzhi; Zhang, Jintun; Ma, Keping

2011-09-28

100

Organochlorine residues in freshwater fishes in Nigeria  

Energy Technology Data Exchange (ETDEWEB)

Several organochlorine pesticide residues in fish from various freshwater ecosystems in Bendel State of Nigeria were investigated. The fish species analyzed were selected among those commonly used for human consumption. Among the compounds identified and quantified were the DDT group, HCB and lindane (..gamma..-BHC). The results indicate an appreciable accumulation in fish of P,P'-DDT, P,P'-DDE and ..gamma..-BHC. The other pesticide residues detected had considerable lower levels.

Atuma, S.S.; Eigbe, C.O.

1985-01-01

 
 
 
 
101

Insights into biodiversity sampling strategies for freshwater microinvertebrate faunas through bioblitz campaigns and DNA barcoding.  

UK PubMed Central (United Kingdom)

BACKGROUND: Biodiversity surveys have long depended on traditional methods of taxonomy to inform sampling protocols and to determine when a representative sample of a given species pool of interest has been obtained. Questions remain as to how to design appropriate sampling efforts to accurately estimate total biodiversity. Here we consider the biodiversity of freshwater ostracods (crustacean class Ostracoda) from the region of Churchill, Manitoba, Canada. Through an analysis of observed species richness and complementarity, accumulation curves, and richness estimators, we conduct an a posteriori analysis of five bioblitz-style collection strategies that differed in terms of total duration, number of sites, protocol flexibility to heterogeneous habitats, sorting of specimens for analysis, and primary purpose of collection. We used DNA barcoding to group specimens into molecular operational taxonomic units for comparison. RESULTS: Forty-eight provisional species were identified through genetic divergences, up from the 30 species previously known and documented in literature from the Churchill region. We found differential sampling efficiency among the five strategies, with liberal sorting of specimens for molecular analysis, protocol flexibility (and particularly a focus on covering diverse microhabitats), and a taxon-specific focus to collection having strong influences on garnering more accurate species richness estimates. CONCLUSIONS: Our findings have implications for the successful design of future biodiversity surveys and citizen-science collection projects, which are becoming increasingly popular and have been shown to produce reliable results for a variety of taxa despite relying on largely untrained collectors. We propose that efficiency of biodiversity surveys can be increased by non-experts deliberately selecting diverse microhabitats; by conducting two rounds of molecular analysis, with the numbers of samples processed during round two informed by the singleton prevalence during round one; and by having sub-teams (even if all non-experts) focus on select taxa. Our study also provides new insights into subarctic diversity of freshwater Ostracoda and contributes to the broader "Barcoding Biotas" campaign at Churchill. Finally, we comment on the associated implications and future research directions for community ecology analyses and biodiversity surveys through DNA barcoding, which we show here to be an efficient technique enabling rapid biodiversity quantification in understudied taxa.

Laforest BJ; Winegardner AK; Zaheer OA; Jeffery NW; Boyle EE; Adamowicz SJ

2013-01-01

102

Comparative radiation impact on biota and man in the area affected by the accident at the Chernobyl nuclear power plant  

International Nuclear Information System (INIS)

A methodological approach for a comparative assessment of ionising radiation effects on man and non-human species, based on the use of Radiation Impact Factor (RIF) - ratios of actual exposure doses to biota species and man to critical dose is described. As such doses, radiation safety standards limiting radiation exposure of man and doses at which radiobiological effects in non-human species were not observed after the Chernobyl accident, were employed. For the study area within the 30 km ChNPP zone dose burdens to 10 reference biota groups and the population (with and without evacuation) and the corresponding RIFs were calculated. It has been found that in 1986 (early period after the accident) the emergency radiation standards for man do not guarantee adequate protection of the environment, some species of which could be affected more than man. In 1991 RIFs for man were considerably (by factor of 20.0-1.1 x 105) higher compared with those for selected non-human species. Thus, for the long term after the accident radiation safety standards for man are shown to ensure radiation safety for biota as well.

2005-01-01

103

Extreme primary and secondary protein structure variability in the chimeric male-transmitted cytochrome c oxidase subunit II protein in freshwater mussels: Evidence for an elevated amino acid substitution rate in the face of domain-specific purifying selection  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Freshwater unionoidean bivalves, and species representing two marine bivalve orders (Mytiloida and Veneroida), exhibit a mode of mtDNA inheritance involving distinct maternal (F) and paternal (M) transmission routes concomitant with highly divergent gender-associated mtDNA genomes. Additionally, male unionoidean bivalves have a ~550 bp 3' coding extension to the cox2 gene (Mcox2e), that is apparently absent from all other metazoan taxa. Results Our molecular sequence analyses of MCOX2e indicate that both the primary and secondary structures of the MCOX2e region are evolving much faster than other regions of the F and M COX2-COX1 gene junction. The near N-terminus ~2/3 of the MCOX2e region contains an interspecifically variable number of predicted transmembrane helices (TMH) and interhelical loops (IHL) whereas the C-terminus ~1/3 is relatively conserved and hydrophilic while containing conserved functional motifs. MCOX2e displays an overall pattern of purifying selection that leads to the preservation of TMH/IHL and C-terminus tail sub-regions. However, 14 amino acid positions in the MCOX2e TMH/IHL sub-region might be targeted by diversifying selection, each representing a site where there exists interspecific variation for the constituent amino acids residing in a TMH or IHL. Conclusion Our results indicate that Mcox2e is unique to unionoidean bivalves, likely the result of a single insertion event that took place over 65 MYA and that MCOX2e is functional. The predicted TMH number, length and position variability likely stems from substitution-based processes rather than the typically implicated insertion/deletion events. MCOX2e has relatively high rates of primary and secondary structure evolution, with some amino acid residues potentially subjected to site-specific positive selection, yet an overall pattern of purifying selection leading to the preservation of the TMH/IHL and hydrophilic C-terminus tail subregions. The more conserved C-terminus tail (relative to the TMH/IHL sub-region of MCOX2e) is likely biologically active because it contains functional motifs. The rapid evolution of primary and secondary structure in MCOX2e, combined with the action of both positive and purifying selection, provide supporting evidence for the hypothesis that MCOX2e has a novel reproductive function within unionoidean bivalves. All tolled, our data indicate that unionoidean bivalve MCOX2 is the first reported chimeric animal mtDNA-encoded protein.

Chapman Eric G; Piontkivska Helen; Walker Jennifer M; Stewart Donald T; Curole Jason P; Hoeh Walter R

2008-01-01

104

Acidification of freshwaters  

Energy Technology Data Exchange (ETDEWEB)

This volume gives an account that draws not only on the main branches of chemistry but also on soil physics, chemistry, hydrology, meteorology, geography, geology, plant physiology, soil microbiology and zoology. The author examine the numerous interacting physical, chemical, and biological, processes that regulate the acidity of freshwaters, a phenomenon that has various causes, including precipitation; acidifying pollutions; and the interaction of plants, soils and water. The relative importance of the different processes is examined.

Cresser, M.S.; Edwards, A.C.

1987-01-01

105

Comparative food chain behaviour and distribution of actinide elements in and around a contaminated fresh-water pond  

International Nuclear Information System (INIS)

The bioaccumulation of sup(233,234)U, 238U, 238Pu, sup(239,240)Pu, 241Am, and 244Cm in both native and introduced biota was studied at Pond 3513, a former low-level radioactive waste settling basin (0.4 ha surface area) at Oak Ridge National Laboratory. This system, which was decommissioned in 1976 after more than 30 years' use, contains approximately 5 Ci of sup(239,240)Pu; inventories of other actinide isotopes are considerably less. Significantly higher concentrations of actinides in fish that were allowed access to sediments indicated that sedimentary particulates may be the primary source of transuranics to biota in shallow fresh-water ecosystems. The study determined habitat, in particular the degree of association of an organism with the sediment/water interface, to be the primary factor in controlling transuranic concentrations in aquatic biota. In most of the biological samples analysed, excluding samples suspected of being contaminated by sediment, 241Am/239Pu, 244Cm/239Pu, and 238U/239Pu ratios were greater than the respective ratios in sediment while sup(233,234)U/238U, and sup(239,240)Pu/238Pu (aquatic biota only) ratios were not different from the respective ratios in sediment. The relative uptake of actinides from contaminated sediment by aquatic and terrestrial biota at this site was U>Cm>=Am>Pu. The relative extractability of actinides from shoreline sediment (using 1 M HNO3 and 0.01 M HCl) was U>Cm approximately equal to Am>Pu. Concentrations of transuranics in water, terrestrial vegetation, and vertebrate carcasses were less than 10% of the recommended public exposure maximum permissible concentration (MPC) of the ICRP, even in this highly contaminated system, which has radioactive inventories atypical of any other fresh-water site now in use or planned for future use in association with nuclear power technologies. (author).

1981-07-31

106

Evolutionary refugia and ecological refuges: key concepts for conserving Australian arid zone freshwater biodiversity under climate change.  

Science.gov (United States)

Refugia have been suggested as priority sites for conservation under climate change because of their ability to facilitate survival of biota under adverse conditions. Here, we review the likely role of refugial habitats in conserving freshwater biota in arid Australian aquatic systems where the major long-term climatic influence has been aridification. We introduce a conceptual model that characterizes evolutionary refugia and ecological refugees based on our review of the attributes of aquatic habitats and freshwater taxa (fishes and aquatic invertebrates) in arid Australia. We also identify methods of recognizing likely future refugia and approaches to assessing the vulnerability of arid-adapted freshwater biota to a warming and drying climate. Evolutionary refugia in arid areas are characterized as permanent, groundwater-dependent habitats (subterranean aquifers and springs) supporting vicariant relicts and short-range endemics. Ecological refugees can vary across space and time, depending on the dispersal abilities of aquatic taxa and the geographical proximity and hydrological connectivity of aquatic habitats. The most important are the perennial waterbodies (both groundwater and surface water fed) that support obligate aquatic organisms. These species will persist where suitable habitats are available and dispersal pathways are maintained. For very mobile species (invertebrates with an aerial dispersal phase) evolutionary refugia may also act as ecological refugees. Evolutionary refugia are likely future refugia because their water source (groundwater) is decoupled from local precipitation. However, their biota is extremely vulnerable to changes in local conditions because population extinction risks cannot be abated by the dispersal of individuals from other sites. Conservation planning must incorporate a high level of protection for aquifers that support refugial sites. Ecological refuges are vulnerable to changes in regional climate because they have little thermal or hydrological buffering. Accordingly, conservation planning must focus on maintaining meta-population processes, especially through dynamic connectivity between aquatic habitats at a landscape scale. PMID:23526791

Davis, Jenny; Pavlova, Alexandra; Thompson, Ross; Sunnucks, Paul

2013-04-18

107

Evolutionary refugia and ecological refuges: key concepts for conserving Australian arid zone freshwater biodiversity under climate change.  

UK PubMed Central (United Kingdom)

Refugia have been suggested as priority sites for conservation under climate change because of their ability to facilitate survival of biota under adverse conditions. Here, we review the likely role of refugial habitats in conserving freshwater biota in arid Australian aquatic systems where the major long-term climatic influence has been aridification. We introduce a conceptual model that characterizes evolutionary refugia and ecological refugees based on our review of the attributes of aquatic habitats and freshwater taxa (fishes and aquatic invertebrates) in arid Australia. We also identify methods of recognizing likely future refugia and approaches to assessing the vulnerability of arid-adapted freshwater biota to a warming and drying climate. Evolutionary refugia in arid areas are characterized as permanent, groundwater-dependent habitats (subterranean aquifers and springs) supporting vicariant relicts and short-range endemics. Ecological refugees can vary across space and time, depending on the dispersal abilities of aquatic taxa and the geographical proximity and hydrological connectivity of aquatic habitats. The most important are the perennial waterbodies (both groundwater and surface water fed) that support obligate aquatic organisms. These species will persist where suitable habitats are available and dispersal pathways are maintained. For very mobile species (invertebrates with an aerial dispersal phase) evolutionary refugia may also act as ecological refugees. Evolutionary refugia are likely future refugia because their water source (groundwater) is decoupled from local precipitation. However, their biota is extremely vulnerable to changes in local conditions because population extinction risks cannot be abated by the dispersal of individuals from other sites. Conservation planning must incorporate a high level of protection for aquifers that support refugial sites. Ecological refuges are vulnerable to changes in regional climate because they have little thermal or hydrological buffering. Accordingly, conservation planning must focus on maintaining meta-population processes, especially through dynamic connectivity between aquatic habitats at a landscape scale.

Davis J; Pavlova A; Thompson R; Sunnucks P

2013-07-01

108

Relationship between water solubility of chlorobenzenes and their effects on a freshwater green alga  

Energy Technology Data Exchange (ETDEWEB)

The effective concentrations of benzene and 12 chlorobenzenes that reduced 50% of the primary productivity (EC/sub 50/) of a freshwater green alga, Ankistrodesmus falcatus, were determined. Benzene was the least toxic chemical and the toxicity increased as the degree of chlorine substitution in the aromatic ring increased. No EC/sub 50/ value could be obtained for HCB. A quantitative relationship was found to exist between water solubility, lipophilicity and the EC/sub 50/. A good correlation was also observed between the EC/sub 50/ for this alga and other toxicity data for various aquatic biota.

Wong, P.T.S.; Chau, Y.K.; Rhamey, J.S.; Docker, M.

1984-01-01

109

Assessment of Marine Biota Doses Arising from the Radioactive Sea Discharges of the COGEMA La Hague Facility. A Comprehensive Case Study (Consensus Appraisal)  

International Nuclear Information System (INIS)

This paper reports an assessment of radiation doses to marine biota arising from the radioactive sea discharges (as liquid effluents) of the COGEMA La Hague facility. The La Hague facility is located in the northwest part of France, in the north-west tip of the Nord-Cotentin Peninsula, along the English Channel south shore. The case study was primarily based on the large amount of data from recent studies of the Nord-Cotentin Radioecology Group (GRNC) and from a recent environmental impact assessment of the La Hague facility. The primary objective of this study was to select a representative set of marine biota for the study area (i.e. the Nord-Cotentin Peninsula coast) and to assess the potential radiological impacts, in terms of biota dose-rates and their related potential health effects on marine biota, arising from the radioactive sea discharges of the COGEMA La Hague facility. For assessing potential effects to biota, the predicted biota dose rates were compared to the available guidance for the protection of populations of non-human biota. The guidance values are based on published data by international organizations (e.g. UNSCEAR and IAEA) and on a screening review of a recent database (by FASSET) on biological effects of ionizing radiation on non-human biota. The major conclusion of the case study was that the predicted dose rates to marine biota attributable to radioactive sea discharges from the La Hague facility are small, and in general, well below comparison guidance levels at which deleterious and observable health effects to populations of marine biota might, according to current knowledge, be expected. The predicted incremental dose rates arising from the La Hague facility are also, in general, well below those caused by the background radioactivity in the region. This conclusion and the dose rate predictions in this study are in close agreement with those for the marine biota of Cap La Hague reported in the MARINAII study recently undertaken for the European Commission. This case study has been presented and discussed at a recent specific workshop of international experts held at La Hague on April 15, 2003. This paper briefly presents the case study and put a particular focus on the study consensus appraisal (which includes the major conclusion stated above) that resulted from the workshop and on an industry perspective on the emerging topic of protection of non-human biota species. The points highlighted in the consensus appraisal have been incorporated in the study final report. The reader is invited to consult the consensus appraisal, contained in the study final report, for an independent and transparent opinion on the La Hague case study that was expressed by a group of international experts. (Author) 15 refs.

2004-01-01

110

Activated chemical defenses suppress herbivory on freshwater red algae.  

UK PubMed Central (United Kingdom)

The rapid life cycles of freshwater algae are hypothesized to suppress selection for chemical defenses against herbivores, but this notion remains untested. Investigations of chemical defenses are rare for freshwater macrophytes and absent for freshwater red algae. We used crayfish to assess the palatability of five freshwater red algae relative to a palatable green alga and a chemically defended aquatic moss. We then assessed the roles of structural, nutritional, and chemical traits in reducing palatability. Both native and non-native crayfish preferred the green alga Cladophora glomerata to four of the five red algae. Batrachospermum helminthosum, Kumanoa holtonii, and Tuomeya americana employed activated chemical defenses that suppressed feeding by 30-60 % following damage to algal tissues. Paralemanea annulata was defended by its cartilaginous structure, while Boldia erythrosiphon was palatable. Activated defenses are thought to reduce ecological costs by expressing potent defenses only when actually needed; thus, activation might be favored in freshwater red algae whose short-lived gametophytes must grow and reproduce rapidly over a brief growing season. The frequency of activated chemical defenses found here (three of five species) is 3-20× higher than for surveys of marine algae or aquatic vascular plants. If typical for freshwater red algae, this suggests that (1) their chemical defenses may go undetected if chemical activation is not considered and (2) herbivory has been an important selective force in the evolution of freshwater Rhodophyta. Investigations of defenses in freshwater rhodophytes contribute to among-system comparisons and provide insights into the generality of plant-herbivore interactions and their evolution.

Goodman KM; Hay ME

2013-04-01

111

Burgess shale-type biotas were not entirely burrowed away  

DEFF Research Database (Denmark)

Burgess Shale-type biotas occur globally in the Cambrian record and offer unparalleled insight into the Cambrian explosion, the initial Phanerozoic radiation of the Metazoa. Deposits bearing exceptionally preserved soft-bodied fossils are unusually common in Cambrian strata; more than 40 are now known. The well-documented decline of soft-bodied preservation following the Middle Cambrian represents the closure of a taphonomic window that was only intermittently open in marine environments thereafter. The prevailing hypothesis for this secular shift in taphonomic conditions of outer shelf environments is that soft-bodied biotas were literally burrowed away from the fossil record by increasing infaunal activity in muddy substrate environments; this would have affected geochemical gradients and increased the efficiency of organic matter recycling in sediments. New and recently published data, however, suggest a more complex scenario. Ichnologic and microstratigraphic data from Burgess Shale-type deposits indicatethat (1) bioturbation exerts a limiting effect on soft-bodied preservation; (2) the observed increase in the depth and extent or bioturbation following the Middle Cambrian would have restricted preservation of Burgess Shale type biotas in a number of settings; but (3) increasing depth and extent of bioturbation would not have affected preservation in many other settings, including the most richly fossiliferous portions of the Chengjiang (China) deposit and the Greater Phyllopod Bed of the Burgess Shale (Canada). Therefore, increasing bioturbation cannot account for the apparent loss of this pathway from the fossil record, and requires that other circumstances, including, but not limited to, widespread benthic anoxia, facilitated widespread exceptional preservation in the Cambrian.

Gaines, Robert R.; Droser, Mary L.

2012-01-01

112

Anthropogenic radionuclides in biota samples from the Caspian Sea  

International Nuclear Information System (INIS)

The Caspian Sea has been recently a subject of many scientific studies mainly related to sea level changes and pollution. For this purpose, two sampling expeditions were organised by IAEA in the Caspian Sea in 1995 and 1996. The aim was to investigate oceanographic conditions, water dynamics and the distribution of anthropogenic radionuclides 90Sr, 137Cs and 239,240Pu in the water column. Considering the unique biodiversity of the Caspian Sea, there has also been interest to obtain information on radionuclide concentrations in biota samples, first of all in sturgeons and in caviar as their production is strongly linked to economical regional needs. The radioactive contamination of Caspian Sea biota has been investigated by analyzing natural 210Po and anthropogenic 137Cs, 239,240Pu and 241Am in biota samples collected in April 1999 offshore of Astrakhan, in the north Caspian Sea. More biota samples from the South West Caspian Sea (Artom Island, June 1999; Devechi District and Neftechala, November 1999) were collected and analyzed for 210Po, 137Cs, 90Sr, 239,240Pu and 241Am. The sampled species were different types of sturgeons (Sevruga, Russkyi Osyotr and Beluga) as well as fresh spawn and caviar. Other fish species (e.g. Cyprinidae) and one algae sample (Cladofila) have also been analysed. Flesh parts have only been analysed in the case of fish samples. The samples were freeze-dried, ground sieved and canned to be counted by gamma-spectrometry for determination of 137Cs. Analytical separation and purification procedures were carried out later. 210Po, 239,240Pu as well as 241Am were measured by alpha-spectrometry whereas 90Sr was measured by beta-spectrometry. The data are reported. In general, radionuclide activities in fish and caviar do not represent any risk for their consumption as they are very low. 239,240Pu and 241Am were close to the limit of detection. When measurable, the 238Pu/239,240Pu ratio is close to the fallout value. 90Sr activities are quite similar in all samples, while concentrations of 137Cs are higher in sturgeons than in cyprinidae fish. This affects the 137Cs/90Sr ratio which varies from 6 to 350. In the caviar and spawn samples, the 137Cs is not as concentrated as in the fish, whereas 90Sr is slightly higher. One caviar sample from the South Western region shows higher levels of plutonium and americium. The algae sample, as expected, has been concentrating these radionuclides as well

2004-01-01

113

[Soil biota and its role in soil ecology  

UK PubMed Central (United Kingdom)

Soil organisms alter soil physical, chemical and biological properties in different ways. The composition and structure of biotic communities at one hierarchical level can influence the spatial heterogeneity of resource at other hierarchical levels, and the latter is supported by a number of biologically relevant spheres-functional domains in soil. In this paper, the role of soil biota in soil ecosystem processes was assessed, and the relationship between soil biodiversity and ecosystem function was presented. Soil ecosystem responses to global change were also discussed.

Liang W; Wen D

2001-02-01

114

Choosing a Weighting Factor for Doses to Biota from Alpha Particles  

International Nuclear Information System (INIS)

The potential risks to non-human biota from exposure to ionizing radiation is an area of considerable current interest, both in Canada and internationally. It is well known that the effects of exposure to ionizing radiation depend not only on the physical quantity absorbed dose, appropriately averaged over a relevant target volume, but also on the type of radiation. It is common to multiply the absorbed dose of a particular type of radiation by a factor to account for the relative biological effectiveness (RBE) of the radiation type. for non-human biota, this factor has also been referred to as an eco dosimetric weighting factor or more simple, the radiation weighting factor. There have been many experimental studies of the RBE of doses from internally deposited alpha emitters for a variety of effects and organisms. Estimated values of RBE range over two orders of magnitude. Selection of the most appropriate value (or values) to apply as a radiation weighting factor is very judgmental and, not too surprisingly, different reviewers have made different selections. currently recommended values range from 5 to 50. This paper reports, on a review of relevant published literature discussing experimental RBE data for internally deposited alpha emitting radionuclides. However, rather than simply adding to that plethora of reviews, we first attempt here to lay out the questions that might be asked during and assessment of the data from experimental studies before coming to our own conclusions. In the end, some 66 relevant papers were identified and reviewed. Recommendations for alpha radiation weighting factors are provided. (Author) 26 Refs.

2004-01-01

115

New occurence of the Cambrian (Stage 4, Series 2) Guanshan Biota in Huize, Yunnan, South China  

Directory of Open Access Journals (Sweden)

Full Text Available Typical elements of the Guanshan Biota are reported from the Cambrian Stage 4 Wulongqing Formation of Huize, Qujing, South China, approximately 100 km north of the Guanshan fossil sites previously reported. Lithostratigraphy and biostratigraphy of the current Zhujiaqing section are also discussed herein. Representatives of various phyla recovered therein include not only previously described sponges, palaeoscolecids, arthropods, brachiopods, echinoderms, and vetulicolians, but also some potential new taxa, e.g. a new species of Vetulicola. This new occurrence not only expands the palaeogeographic distribution of the Guanshan Biota, but also strengthens the ties between the younger Chengjiang Biota and the older Kaili Biota (and also the coeval Burgess Shale community)

Liu J N; Ou Q; Han J; Zhang Z F; He T J; Yao X Y; Fu D J; Shu D G

2012-01-01

116

The Caspian Lake: history, biota, structure and function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The elongate, endorheic Caspian Lake has a north-south orientation and its main freshwater inflow, the Volga River, enters at the shallow north end. Two deep basins occupy its central and southern regions. These facts lead to horizontal differences in temperature, salinity, and ecology. Nutrient lev...

Dumont, H.J.

117

Modelling Radiation Exposure and Radionuclide Transfer for Non-human Species. Report of the Biota Working Group of EMRAS Theme 3  

International Nuclear Information System (INIS)

Internationally, the ICRP, IAEA and European Commission (EC) are addressing environmental protection as an element of their revision of Recommendations and Basic Safety Standards. Some countries already have requirements and guidelines for the protection of non-human biota. For instance, in England and Wales, the requirement to assess impacts affecting Natura 2000 sites has been interpreted to include ionising radiation. In the USA, biota protection guidelines and dose rates are contained in USDOE Orders 5400.5 and 450.1. In response to these developments, a number of models and approaches have been developed specifically to estimate the exposure of non-human biota to ionising radiations. Some countries (e.g. Canada, Finland, England and Wales, and the USA) are now using these within their national regulatory frameworks for (existing and proposed) nuclear and other sites that may release radioactivity to the environment. Software and/or documentation for some of these approaches are readily available and hence third parties are able to use them when conducting assessments. The Biota Working Group (BWG) of the IAEA Environmental Modelling for Radiation Safety programme was formed in 2004 to address the relative lack of validation and intercomparison of the different models and approaches. The primary objective of the BWG, was: 'to improve Member State's capabilities for protection of the environment by comparing and validating models being used, or developed, for biota dose assessment (that may be used) as part of regulatory process of licensing and compliance monitoring of authorised releases of radionuclides'. Group members included modellers, regulators, industry and researchers. In total, 15 models and approaches were applied to one or more of the four exercises conducted by the BWG. The models/approaches applied encompass those being developed, and in some instances, used in a regulatory context, in Belgium, Canada, France, Lithuania, Russia, the UK and the USA, as well as the outputs of recent EC EURATOM programmes. The participating models included those freely available to any interested users. The four intercomparison exercises included evaluations of the basic components of the models assuming 1 Bq per unit media or 1 Bq kg-1 in the organism, and two scenario (one freshwater and one terrestrial) applications in which model predictions were compared to available field measurements. The work of the BWG has clearly demonstrated that the largest contribution to variability between model predictions, and comparison with available data, is the parameterisation of the models transfer components. The methods used to determine absorbed dose rate contribute relatively little to variability between model outputs. The report concludes with recommendations for future activities within the EMRAS II programme.

2000-01-00

118

Modelling Radiation Exposure and Radionuclide Transfer for Non-human Species. Report of the Biota Working Group of EMRAS Theme 3  

International Nuclear Information System (INIS)

[en] Internationally, the ICRP, IAEA and European Commission (EC) are addressing environmental protection as an element of their revision of Recommendations and Basic Safety Standards. Some countries already have requirements and guidelines for the protection of non-human biota. For instance, in England and Wales, the requirement to assess impacts affecting Natura 2000 sites has been interpreted to include ionising radiation. In the USA, biota protection guidelines and dose rates are contained in USDOE Orders 5400.5 and 450.1. In response to these developments, a number of models and approaches have been developed specifically to estimate the exposure of non-human biota to ionising radiations. Some countries (e.g. Canada, Finland, England and Wales, and the USA) are now using these within their national regulatory frameworks for (existing and proposed) nuclear and other sites that may release radioactivity to the environment. Software and/or documentation for some of these approaches are readily available and hence third parties are able to use them when conducting assessments. The Biota Working Group (BWG) of the IAEA Environmental Modelling for Radiation Safety programme was formed in 2004 to address the relative lack of validation and intercomparison of the different models and approaches. The primary objective of the BWG, was: 'to improve Member State's capabilities for protection of the environment by comparing and validating models being used, or developed, for biota dose assessment (that may be used) as part of regulatory process of licensing and compliance monitoring of authorised releases of radionuclides'. Group members included modellers, regulators, industry and researchers. In total, 15 models and approaches were applied to one or more of the four exercises conducted by the BWG. The models/approaches applied encompass those being developed, and in some instances, used in a regulatory context, in Belgium, Canada, France, Lithuania, Russia, the UK and the USA, as well as the outputs of recent EC EURATOM programmes. The participating models included those freely available to any interested users. The four intercomparison exercises included evaluations of the basic components of the models assuming 1 Bq per unit media or 1 Bq kg-1 in the organism, and two scenario (one freshwater and one terrestrial) applications in which model predictions were compared to available field measurements. The work of the BWG has clearly demonstrated that the largest contribution to variability between model predictions, and comparison with available data, is the parameterisation of the models transfer components. The methods used to determine absorbed dose rate contribute relatively little to variability between model outputs. The report concludes with recommendations for future activities within the EMRAS II programme.

2000-01-00

119

Transboundary Freshwater Dispute Database  

Science.gov (United States)

The database includes 150 water related treaties and 39 US compacts. The International Treaties and Compacts section is searchable by nation, basin, issues, conflict resolution mechanisms, non-water linkages, and date. US Compacts are searchable by state, basin, focus and date. For all treaties or compacts there is a summary of the agreement, the parties involved, allocations if applicable and other information pertinent to a specific agreement. There is also information available on indigenous approaches to water conflict resolution, a digitized inventory of the world's river basins with data about those basins, and a bibliography featuring publications about transboundary freshwater dispute resolution.

120

Interactions between marine biota and ENSO: a conceptual model analysis  

Directory of Open Access Journals (Sweden)

Full Text Available We develop a conceptual coupled atmosphere-ocean-ecosystem model for the tropical Pacific to investigate the interaction between marine biota and the El Niño-Southern Oscillation (ENSO). Ocean and atmosphere are represented by a two-box model for the equatorial Pacific cold tongue and the warm pool, including a simplified mixed layer scheme. Marine biota are represented by a three-component (nutrient, phytoplankton, and zooplankton) ecosystem model. The atmosphere-ocean model exhibits an oscillatory state which qualitatively captures the main physics of ENSO. During an ENSO cycle, the variation of nutrient upwelling, and, to a small extent, the variation of photosynthetically available radiation force an ecosystem oscillation. The simplified ecosystem in turn, due to the effect of phytoplankton on the absorption of shortwave radiation in the water column, leads to (1) a warming of the tropical Pacific, (2) a reduction of the ENSO amplitude, and (3) a prolongation of the ENSO period. We qualitatively investigate these bio-physical coupling mechanisms using continuation methods. It is demonstrated that bio-physical coupling may play a considerable role in modulating ENSO variability.

M. Heinemann; A. Timmermann; U. Feudel

2011-01-01

 
 
 
 
121

Invasive alien freshwater snail species in the Kruger National Park, South Africa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An account is given of all invasive alien freshwater snail species samples found in the Kruger National Park currently on record in the National Freshwater Snail Collection(NFSC) database. This report mainly focuses on samples collected during surveys of selected water bodies in the Kruger National ...

Kenné N. De Kock; Cornelius T. Wolmarans

122

Pesticide toxicity index for freshwater aquatic organisms, 2nd edition  

Science.gov (United States)

The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is designed to assess current water-quality conditions, changes in water quality over time, and the effects of natural and human factors on water quality for the Nation's streams and ground-water resources. For streams, one of the most difficult parts of the assessment is to link chemical conditions to effects on aquatic biota, particularly for pesticides, which tend to occur in streams as complex mixtures with strong seasonal patterns. A Pesticide Toxicity Index (PTI) was developed that combines pesticide exposure of aquatic biota (measured concentrations of pesticides in stream water) with acute toxicity estimates (standard endpoints from laboratory bioassays) to produce a single index value for a sample or site. The development of the PTI was limited to pesticide compounds routinely measured in NAWQA studies and to toxicity data readily available from existing databases. Qualifying toxicity data were found for one or more types of test organisms for 124 of the 185 pesticide compounds measured in NAWQA samples, but with a wide range of available bioassays per compound (1 to 232). In the databases examined, there were a total of 3,669 bioassays for the 124 compounds, including 398 48-hour EC50 values (concentration at which 50 percent of test organisms exhibit a sublethal response) for freshwater cladocerans, 699 96-hour LC50 values (concentration lethal to 50 percent of test organisms) for freshwater benthic invertebrates, and 2,572 96-hour LC50 values for freshwater fish. The PTI for a particular sample is the sum of toxicity quotients (measured concentration divided by the median toxicity concentration from bioassays) for each detected pesticide, and thus, is based on the concentration addition model of pesticide toxicity. The PTI can be calculated for specific groups of pesticides and for specific taxonomic groups. Although the PTI does not determine whether water in a sample is toxic to aquatic organisms, its values can be used to rank or compare the toxicity of samples or sites on a relative basis for use in further analysis or additional assessments. The PTI approach may be useful as a basis for comparing the potential significance of pesticides in different streams on a common basis, for evaluating relations between pesticide exposure and observed biological conditions, and for prioritizing where further studies are most needed.

Munn, Mark D.; Gilliom, Robert J.; Moran, Patrick W.; Nowell, Lisa H.

2006-01-01

123

Effects of shoreline treatment methods on intertidal biota in Prince William Sound  

International Nuclear Information System (INIS)

Several studies conducted in Prince William Sound during 1989 were directed at assessing short term biological effects of treatment methods considered or employed for treating oil contaminated beaches. The four treatment alternatives evaluated in this paper are: low pressure warm water wash (LP-WW); high pressure hot water wash (HP-HW); the dispersant Corexit 7664; and the beach cleaner Corexit 9580 M2. Effects on the biota were assessed primarily on the basis of changes in the abundance of dominant taxa and the magnitude of selected community attributes (such as percent cover by algae or animals, and number of taxa). Significant reductions in one or more community or population attributes, and increases in the percent of dead mussels were observed in response to all types of treatment but the strongest and most consistent effects were observed following high pressure hot water treatment, which was also accompanied by heavy mortality in rockweed. Generally, the programs were not designed to discriminate among the potential causes of damage. However, available data suggest that neither chemical nor LP-WW treatments caused significant thermal impacts in the intertidal biota. In contrast, temperature appeared to cause significant mortality in the dominant plants and grazing and filter-feeding animals in HP-HW treatment sites. Observations of displacement and mortality for clams and mussels suggest that physical effects may be substantial in some cases. Of the types of treatment examined, dispersant and beach cleaner treatments appeared to be accompanied with the smallest number of significant changes in abundance; however, this conclusion is weak because the LP-WW wash accompanying chemical applications during the tests was sometimes less rigorous than when performed by itself. LP-WW treatment was accompanied by an intermediate level of changes whereas HP-HW treatment was accompanied with the highest percentage of changes, nearly all of which were decreases.

1993-04-01

124

Assessing impacts of ionizing radiation on non-human biota: the ERICA tool  

International Nuclear Information System (INIS)

There have been significant developments in the last few years concerning methods to explicitly quantify impacts on the environment arising from exposure by ionising radiation. Central to the ERICA integrated approach is the quantification of environmental risk whereby data on environmental transfer and dosimetry are combined to provide a measure of exposure which is compared to exposure levels at which detrimental effects are known to occur. In view of the large data sets underpinning the assessment approach and the potential to introduce errors when performing numerous calculations manually, a supporting computer-based tool (the ERICA Tool) has been developed. The ERICA Tool is a computerised, flexible software system that has a structure based upon the ERICA Integrated Assessment tiered approach to assessing the radiological risk to biota. The user is guided through the assessment process, recording information and decisions as the assessment progresses. The tool allows the necessary calculations to be performed to estimate risks to selected biota. Tier 1 assessments use pre-calculated environmental media concentration limits to estimate risk quotients and require inputs in the form of media concentrations. At Tier 2 dose-rates are calculated but at this stage, the user is allowed to examine and edit most of the parameters used in the calculation. For Tier 3 assessments, the same flexibility as Tier 2 is allowed but assessments may be run probability if the underling parameter probability distribution functions are defined. Results from the tool can be put into context using incorporated data on dose-effects relationships and background dose-rates. (author)

2008-01-01

125

Radiation protection of natural ecosystems: Primary and secondary dose limits to biota  

International Nuclear Information System (INIS)

A methodological approach is proposed for developing criteria for the radiation protection of natural ecosystems, based on establishing the general (primary) and site-specific (secondary) limits of chronic radiation dose rates to biota. The screening procedure is described for the radiation protection of biota on the territories with the increased levels of radioactive contamination

1998-09-04

126

Experimental study of subarctic magnetosphere conditions as possible exogenous factor for northern biota  

International Nuclear Information System (INIS)

The possible role f some magnetosphere processes effects on northern biota was investigated under laboratory conditions. The some specific for Kola subarctic area magnetosphere pulsation time series were responses in cereal plants which appear as change of growth time course were found. The results of the study shown the one possible way of solar-terrestrial effects on northern biota. 7 refs.

1995-01-01

127

Taiwan's industrial heavy metal pollution threatens terrestrial biota  

International Nuclear Information System (INIS)

The bioconcentration levels of essential (Cu, Fe, Mg, Mn, and Zn) and non-essential (As, Cd, Hg, Pb, and Sn) elements have been investigated in different terrestrial biota such as fungi, plant, earthworm, snail, crab, insect, amphibian, lizard, snake, and bat including the associated soil, to investigate the ecosystem health status in Kenting National Park, Taiwan. High bioconcentrations of Cd, Hg, and Sn in snail, earthworm, crab, lizard, snake, and bat indicated a contaminated terrestrial ecosystem. High concentrations of Cd, Hg, and Sn in plant species, effective bioaccumulation of Cd by earthworm, snail, crab and bat, as well as very high levels of Hg found in invertebrates, amphibians, and reptiles revealed a strong influence from industrial pollution on the biotic community. This study for the first time presents data on the impact of heavy metal pollution on various terrestrial organisms in Taiwan. - Metal effects occur at any terrestrial levels in Taiwan.

2006-01-01

128

The Decline of Freshwater Ecosystems  

Science.gov (United States)

This article discusses the risks that freshwater ecosystems face and how species nearby are affected by dams, dredging, and channelization of streams. It points out that even though freshwater ecosystems are limited in extent, covering about 1 percent of the Earth's surface, they are highly diverse and contain a disproportionally large number of the world's species. Statistics are given to illustrate the increase in waterways that have been altered for navigation. Some actions that are being taken to reduce threats to freshwater ecosystems are also mentioned.

1999-01-01

129

Application of an environmental impact assessment methodology to a site discharging low levels of radioactivity to a freshwater environment in Norway.  

Science.gov (United States)

Significant shifts in opinion regarding environmental protection from ionising radiation have resulted in the development and availability of bespoke approaches for the assessment of impacts on wildlife from radioactive contaminants. The application of such assessment methodologies to actual situations, however, remains relatively limited. This paper describes the implementation of the ERICA Integrated Approach and associated tools within the context of routine discharges of radioactive materials to a freshwater environment. The article follows the implementation through its relevant stages and discusses strengths and weaknesses of the approach in relation to the case study. For current discharge levels, 137Cs and 60Co constitute the main dose contributors to the majority of reference organisms studied, although 241Am and 3H are the main contributors for the phyto- and zooplankton categories. Patterns are observed depending on whether the reference organism is sediment-associated or not. At current discharge levels, none of the reference organisms exceeded or approached the selected screening level, and impacts on biota could be regarded as negligible. PMID:20237837

Hosseini, Ali; Brown, Justin Emrys; Dowdall, Mark; Standring, William; Strand, Per

2010-03-18

130

Application of an environmental impact assessment methodology to a site discharging low levels of radioactivity to a freshwater environment in Norway.  

UK PubMed Central (United Kingdom)

Significant shifts in opinion regarding environmental protection from ionising radiation have resulted in the development and availability of bespoke approaches for the assessment of impacts on wildlife from radioactive contaminants. The application of such assessment methodologies to actual situations, however, remains relatively limited. This paper describes the implementation of the ERICA Integrated Approach and associated tools within the context of routine discharges of radioactive materials to a freshwater environment. The article follows the implementation through its relevant stages and discusses strengths and weaknesses of the approach in relation to the case study. For current discharge levels, 137Cs and 60Co constitute the main dose contributors to the majority of reference organisms studied, although 241Am and 3H are the main contributors for the phyto- and zooplankton categories. Patterns are observed depending on whether the reference organism is sediment-associated or not. At current discharge levels, none of the reference organisms exceeded or approached the selected screening level, and impacts on biota could be regarded as negligible.

Hosseini A; Brown JE; Dowdall M; Standring W; Strand P

2011-02-01

131

Comprehensive monitoring of synthetic musk compounds from freshwater to coastal environments in Korea: With consideration of ecological concerns and bioaccumulation.  

UK PubMed Central (United Kingdom)

This study investigated the concentration levels of synthetic musk compounds (SMCs), including HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyran), AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene), MK (Musk ketone), and MX (Musk xylene), in freshwater, freshwater and coastal sediments, and coastal bivalves from freshwater to coastal environments. The levels in freshwater close to sewage treatment plants (STPs) showed higher contamination and suggested a medium to high ecological risk, especially posed by MK making more than 65% contribution to the combined risk by the total SMCs. STP effluent discharge points showed higher SMC concentrations in freshwater and coastal sediments. Predominant HHCB contributions regardless of sample types such as abiota and biota were consistent with the greater usage of HHCB than AHTN and MK in Korea. However, the higher contributions of AHTN than those predicted from AHTN consumption in Korea indicate the need for further research on the characteristic properties of individual SMCs, including partitioning, biomagnification, degradation, and metabolism for a realistic risk characterization. With respect to the highest HHCB levels in coastal bivalves reported, we determined the biota-sediment accumulation factor (BSAF) to understand the bioaccumulation of SMCs between coastal sediment and bivalves. The calculated BSAF values suggested that SMCs in bivalves were not biomagnified via the food chain but mostly partitioned from sediment. To our knowledge, this is the first study to measure BSAF values of SMCs, especially HHCB, AHTN, and MK, in coastal bivalve samples.

Lee IS; Kim UJ; Oh JE; Choi M; Hwang DW

2013-08-01

132

Impacts of mine drainage and other nonpoint source pollutants on aquatic biota in the upper Powell River System, Virginia  

Energy Technology Data Exchange (ETDEWEB)

The Clinch-Powell River system of Virginia and Tennessee, USA, is among the most biologically diverse ecosystems in the world, and has been identified as a conservation priority of national importance. Other researchers have attributed declines in Powell River freshwater mussel populations to coal mining-related activities. The objectives of this paper are to synthesize the results of several studies aimed at assessing acid mine drainage (AMD) impacts in the Powell River watershed, and to describe the relative roles of AMD, nutrient loading, and urban runoff in structuring the benthic macroinvertebrate communities of the Powell River. Impacts ranged from acute toxicity due to the combination of acid and metals, acute aluminum toxicity in circumneutral pH waters, and physical impacts from solid ferrihydrite, to decreased clam growth due to urban runoff. These findings support the concern that AMD negatively impacts aquatic biota in the Powell River watershed in a variety of ways, and emphasize the importance of taking measures to properly reclaim areas that are producing mine drainage. However, past-mining related pollutants are not the only source of aquatic-community impact in these watersheds, as nutrient loading and urban runoff both were associated with substantial changes in community structure and clam growth.

Soucek, D.J.; Cherry, D.S.; Zipper, C.E. [Illinois National History Survey, Champaign, IL (United States)

2003-06-01

133

The BIOTA Biodiversity Observatories in Africa--a standardized framework for large-scale environmental monitoring.  

UK PubMed Central (United Kingdom)

The international, interdisciplinary biodiversity research project BIOTA AFRICA initiated a standardized biodiversity monitoring network along climatic gradients across the African continent. Due to an identified lack of adequate monitoring designs, BIOTA AFRICA developed and implemented the standardized BIOTA Biodiversity Observatories, that meet the following criteria (a) enable long-term monitoring of biodiversity, potential driving factors, and relevant indicators with adequate spatial and temporal resolution, (b) facilitate comparability of data generated within different ecosystems, (c) allow integration of many disciplines, (d) allow spatial up-scaling, and (e) be applicable within a network approach. A BIOTA Observatory encompasses an area of 1 km(2) and is subdivided into 100 1-ha plots. For meeting the needs of sampling of different organism groups, the hectare plot is again subdivided into standardized subplots, whose sizes follow a geometric series. To allow for different sampling intensities but at the same time to characterize the whole square kilometer, the number of hectare plots to be sampled depends on the requirements of the respective discipline. A hierarchical ranking of the hectare plots ensures that all disciplines monitor as many hectare plots jointly as possible. The BIOTA Observatory design assures repeated, multidisciplinary standardized inventories of biodiversity and its environmental drivers, including options for spatial up- and downscaling and different sampling intensities. BIOTA Observatories have been installed along climatic and landscape gradients in Morocco, West Africa, and southern Africa. In regions with varying land use, several BIOTA Observatories are situated close to each other to analyze management effects.

Jürgens N; Schmiedel U; Haarmeyer DH; Dengler J; Finckh M; Goetze D; Gröngröft A; Hahn K; Koulibaly A; Luther-Mosebach J; Muche G; Oldeland J; Petersen A; Porembski S; Rutherford MC; Schmidt M; Sinsin B; Strohbach BJ; Thiombiano A; Wittig R; Zizka G

2012-01-01

134

Are metals of antifouling paints transferred to marine biota?  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Devido sua alta toxicidade, o TBT está banido desde 2003, o que resultou na re-utilização de tintas a base de cobre. O objetivo deste trabalho é determinar se os metais provenientes das tintas anti-incrustantes (AFP) são transferidos para organismos bentônicos da Baía de Guanabara (BG) (Rio de janeiro, Brasil). Concentrações de metais foram analisadas em duas espécies de algas Ulva flexuosa e U. fasciata e no isópoda, Sphaeroma serratum, em duas áreas de marin (more) as em locais de substrato artificial coberto com tintas AFP e em locais de substrato natural. Também foram coletadas amostras em uma área oceânica (controle). Concentrações de Cd, Cr, Cu, Pb e Zn foram determinadas por Espectrofotometria de Absorção Atômica. Concentrações mais elevadas de Cu, Pb e Zn foram detectadas na BG em ambas espécies de algas em relação a área controle. Dentre as espécies de algas e do isópoda da BG, as populações coletadas sobre as superfícies cobertas com AFP apresentaram concentrações significativamente mais elevadas do que as populações do substrato natural. Os resultados obtidos demonstram que a liberação de metais presentes nas AFP dos decks e embarcações, estão sendo acumulados pelas algas e isópodas. Esses resultados indicam que o revestimento com AFP é a principal fonte de metais para a biota de marinas em áreas da BG. Abstract in english Because of its high toxicity, TBT (trybutiltin) was banned since 2003, which resulted in a greater re-use of Cu as based-biocide in antifouling paints (AFP). The aim of this work is to determine if metals form of AFP are transferred to benthic organisms from Guanabara Bay (GB) (Rio de Janeiro, Brazil). Metal concentrations were measured in two main fouling algae species Ulva flexuosa and U. fasciata and one isopod species, Sphaeroma serratum, in two GB marinas areas from (more) sites with artificial substrate covered by AFP and natural substrate.In addition, control samples were collected in an adjacent open ocean area. Concentrations of Cd, Cr, Cu, Pb and Zn were determined by Atomic Absortion Spectrophotometry. Higher concentrations of Cu, Pb and Zn were detected in both algal species from GB in relation to control areas. Among samples of algae and isopod species from GB, populations collected over artificial surfaces covered by AFP presented significantly higher metal concentration than population of rocky natural substrate. Our data showed that the leaching of metals by antifouling paints present on decks and boats are being taken up by algae and isopods. These results indicate that antifouling coatings are the main source of heavy metal to biota of GB marina area.

Paradas, Wladimir C.; Amado Filho, Gilberto M.

2007-03-01

135

Are metals of antifouling paints transferred to marine biota?  

Directory of Open Access Journals (Sweden)

Full Text Available Because of its high toxicity, TBT (trybutiltin) was banned since 2003, which resulted in a greater re-use of Cu as based-biocide in antifouling paints (AFP). The aim of this work is to determine if metals form of AFP are transferred to benthic organisms from Guanabara Bay (GB) (Rio de Janeiro, Brazil). Metal concentrations were measured in two main fouling algae species Ulva flexuosa and U. fasciata and one isopod species, Sphaeroma serratum, in two GB marinas areas from sites with artificial substrate covered by AFP and natural substrate.In addition, control samples were collected in an adjacent open ocean area. Concentrations of Cd, Cr, Cu, Pb and Zn were determined by Atomic Absortion Spectrophotometry. Higher concentrations of Cu, Pb and Zn were detected in both algal species from GB in relation to control areas. Among samples of algae and isopod species from GB, populations collected over artificial surfaces covered by AFP presented significantly higher metal concentration than population of rocky natural substrate. Our data showed that the leaching of metals by antifouling paints present on decks and boats are being taken up by algae and isopods. These results indicate that antifouling coatings are the main source of heavy metal to biota of GB marina area.Devido sua alta toxicidade, o TBT está banido desde 2003, o que resultou na re-utilização de tintas a base de cobre. O objetivo deste trabalho é determinar se os metais provenientes das tintas anti-incrustantes (AFP) são transferidos para organismos bentônicos da Baía de Guanabara (BG) (Rio de janeiro, Brasil). Concentrações de metais foram analisadas em duas espécies de algas Ulva flexuosa e U. fasciata e no isópoda, Sphaeroma serratum, em duas áreas de marinas em locais de substrato artificial coberto com tintas AFP e em locais de substrato natural. Também foram coletadas amostras em uma área oceânica (controle). Concentrações de Cd, Cr, Cu, Pb e Zn foram determinadas por Espectrofotometria de Absorção Atômica. Concentrações mais elevadas de Cu, Pb e Zn foram detectadas na BG em ambas espécies de algas em relação a área controle. Dentre as espécies de algas e do isópoda da BG, as populações coletadas sobre as superfícies cobertas com AFP apresentaram concentrações significativamente mais elevadas do que as populações do substrato natural. Os resultados obtidos demonstram que a liberação de metais presentes nas AFP dos decks e embarcações, estão sendo acumulados pelas algas e isópodas. Esses resultados indicam que o revestimento com AFP é a principal fonte de metais para a biota de marinas em áreas da BG.

Wladimir C. Paradas; Gilberto M. Amado Filho

2007-01-01

136

Assessment of mercury and methylmercury in water, sediment, and biota in Sulphur Creek in the vicinity of the Clyde Gold Mine and the Elgin Mercury Mine, Colusa County, California  

Science.gov (United States)

At the request of the U.S. Bureau of Land Management, we performed a study during April–July 2010 to characterize mercury (Hg), monomethyl mercury (MMeHg), and other geochemical constituents in sediment, water, and biota at the Clyde Gold Mine and the Elgin Mercury Mine, located in neighboring subwatersheds of Sulphur Creek, Colusa County, California. This study was in support of a Comprehensive Environmental Response, Compensation, and Liability Act - Removal Site Investigation. The investigation was in response to an abatement notification from the California Central Valley Regional Water Quality Control Board to evaluate the release of Hg from the Clyde and Elgin mines. Samples of water, sediment, and biota (aquatic macroinvertebrates) were collected from sites upstream and downstream from the two mine sites to evaluate the level of Hg contamination contributed by each mine to the aquatic ecosystem. Physical parameters, as well as dissolved organic carbon, total Hg (HgT), and MMeHg were analyzed in water and sediment. Other relevant geochemical constituents were analyzed in sediment, filtered water, and unfiltered water. Samples of aquatic macroinvertebrates from each mine were analyzed for HgT and MMeHg. The presence of low to moderate concentrations of HgT and MMeHg in water, sediment, and biota from the Freshwater Branch of Sulphur Creek, and the lack of significant increases in these concentrations downstream from the Clyde Mine indicated that this mine is not a significant source of Hg to the watershed during low flow conditions. Although concentrations of HgT and MMeHg were generally higher in samples of sediment and water from the Elgin Mine compared to the Clyde Mine, concentrations in comparable biota from the two mine areas were similar. It is likely that highly saline effluent from nearby hot springs contribute more Hg to the West Fork of Sulphur Creek than the mine waste material at the Elgin Mine.

Hothem, Roger L.; Rytuba, James J.; Brussee, Brianne E.; Goldstein, Daniel N.

2013-01-01

137

Making sense of ocean biota: how evolution and biodiversity of land organisms differ from that of the plankton.  

UK PubMed Central (United Kingdom)

The oceans cover 70% of the planet's surface, and their planktonic inhabitants generate about half the global primary production, thereby playing a key role in modulating planetary climate via the carbon cycle. The ocean biota have been under scientific scrutiny for well over a century, and yet our understanding of the processes driving natural selection in the pelagic environment - the open water inhabited by drifting plankton and free-swimming nekton - is still quite vague. Because of the fundamental differences in the physical environment, pelagic ecosystems function differently from the familiar terrestrial ecosystems of which we are a part. Natural selection creates biodiversity but understanding how this quality control of random mutations operates in the oceans - which traits are selected for under what circumstances and by which environmental factors, whether bottom-up or top-down - is currently a major challenge. Rapid advances in genomics are providing information, particularly in the prokaryotic realm, pertaining not only to the biodiversity inventory but also functional groups. This essay is dedicated to the poorly understood tribes of planktonic protists (unicellular eukaryotes) that feed the ocean's animals and continue to run the elemental cycles of our planet. It is an attempt at developing a conceptually coherent framework to understand the course of evolution by natural selection in the plankton and contrast it with the better-known terrestrial realm. I argue that organism interactions, in particular co-evolution between predators and prey (the arms race), play a central role in driving evolution in the pelagic realm. Understanding the evolutionary forces shaping ocean biota is a prerequisite for harnessing plankton for human purposes and also for protecting the oceanic ecosystems currently under severe stress from anthropogenic pressures.

Smetacek V

2012-09-01

138

Thiols in a Connecticut Stratified Freshwater Lake  

Science.gov (United States)

Thiols are an important class of dissolved reduced sulfur (DRS) species in aquatic environments. They are generally formed from biological processes or during diagenesis of biogenic matter. Thiols can affect the biogeochemistry of B-type metals as they form strong complexes that influence trace metal speciation, bioavailability and toxicity. While current literature focuses on the biogeochemistry of thiols in marine systems, little is known about the biogeochemistry of thiols in oxic freshwaters. We chose to study thiols in Linsley Pond a stratified freshwater lake that has been extensively studied by Hutchinson. Our goals were to identify and quantify the range of thiols present throughout this small lake. Additionally, we hoped to discern the environmental factors that influence the production and distribution of thiols in the water column, and to evaluate importance of thiols in trace metal speciation. To identify and quantify various thiols in freshwaters, we adopted a sensitive and selective analytical method, which involves precolumn fluorometric labeling coupled to high performance liquid chromatography and sensitive fluorescence detection. Using this method, our analytical detection limit is below one nanomolar. Among others, two thiol species were observed in Linsley Pond: 3-mercaptopropionic acid (3-MPA) and glutathione (GSH). 3-MPA exists in both oxic and anoxic water layers at nanomolar levels, and increases from surface to bottom. GSH is only detected in subsurface layer and co-varies with Chl a, indicating possible biological sources of GSH in these layers. There is a third, unidentified thiol species which is currently under investigation. The unidentified thiol species appears only in anoxic lake waters, and tests indicate that it is not PC2 (phytochelatin with 2 glutamic acid-cysteine units). Throughout the water column, concentrations of all three thiols are greater in whole water samples than in the dissolved phase (0.45 um).

Hu, H.; Mylon, S. E.; Benoit, G.

2003-12-01

139

Effects of soil biota from different ranges on Robinia invasion: acquiring mutualists and escaping pathogens.  

Science.gov (United States)

The net effects of soil biota on exotic invaders can be variable, in part, because net effects are produced by many interacting mutualists and antagonists. Here we compared mutualistic and antagonistic biota in soils collected in the native, expanded, and invasive range of the black locust tree, Robinia pseudoacacia. Robinia formed nodules in all soils with a broad phylogenetic range of N-fixing bacteria, and leaf N did not differ among the different sources of soil. This suggests that the global expansion of Robinia was not limited by the lack of appropriate mutualistic N-fixers. Arbuscular mycorrhizal fungi (AMF) from the native range stimulated stronger positive feedbacks than AMF from the expanded or invasive ranges, a biogeographic difference not described previously for invasive plants. Pythium taxa collected from soil in the native range were not more pathogenic than those from other ranges; however, feedbacks produced by the total soil biota were more negative from soils from the native range than from the other ranges, overriding the effects of AMF. This suggests that escape from other pathogens in the soil or the net negative effects of the whole soil community may contribute to superior performance in invaded regions. Our results suggest that important regional evolutionary relationships may occur among plants and soil biota, and that net effects of soil biota may affect invasion, but in ways that are not easily explained by studying isolated components of the soil biota. PMID:21661564

Callaway, Ragan M; Bedmar, Eulogio J; Reinhart, Kurt O; Silvan, Cinta Gómez; Klironomos, John

2011-05-01

140

Effects of soil biota from different ranges on Robinia invasion: acquiring mutualists and escaping pathogens.  

UK PubMed Central (United Kingdom)

The net effects of soil biota on exotic invaders can be variable, in part, because net effects are produced by many interacting mutualists and antagonists. Here we compared mutualistic and antagonistic biota in soils collected in the native, expanded, and invasive range of the black locust tree, Robinia pseudoacacia. Robinia formed nodules in all soils with a broad phylogenetic range of N-fixing bacteria, and leaf N did not differ among the different sources of soil. This suggests that the global expansion of Robinia was not limited by the lack of appropriate mutualistic N-fixers. Arbuscular mycorrhizal fungi (AMF) from the native range stimulated stronger positive feedbacks than AMF from the expanded or invasive ranges, a biogeographic difference not described previously for invasive plants. Pythium taxa collected from soil in the native range were not more pathogenic than those from other ranges; however, feedbacks produced by the total soil biota were more negative from soils from the native range than from the other ranges, overriding the effects of AMF. This suggests that escape from other pathogens in the soil or the net negative effects of the whole soil community may contribute to superior performance in invaded regions. Our results suggest that important regional evolutionary relationships may occur among plants and soil biota, and that net effects of soil biota may affect invasion, but in ways that are not easily explained by studying isolated components of the soil biota.

Callaway RM; Bedmar EJ; Reinhart KO; Silvan CG; Klironomos J

2011-05-01

 
 
 
 
141

An overview of UV-absorbing compounds (organic UV filters) in aquatic biota.  

UK PubMed Central (United Kingdom)

The purpose of this article is to summarize biological monitoring information on UV-absorbing compounds, commonly referred as organic UV filters or sunscreen agents, in aquatic ecosystems. To date a limited range of species (macroinvertebrates, fish, and birds), habitats (lakes, rivers, and sea), and compounds (benzophenones and camphors) have been investigated. As a consequence there is not enough data enabling reliable understanding of the global distribution and effect of UV filters on ecosystems. Both liquid chromatography and gas chromatography coupled with mass spectrometry-based methods have been developed and applied to the trace analysis of these pollutants in biota, enabling the required selectivity and sensitivity. As expected, the most lipophilic compounds occur most frequently with concentrations up to 7112 ng g(-1) lipids in mussels and 3100 ng g(-1) lipids (homosalate) in fish. High concentrations have also been reported for 4-methylbenzilidenecamphor (up to 1800 ng g(-1) lipids) and octocrylene (2400 ng g(-1) lipids). Many fewer studies have evaluated the potential bioaccumulation and biomagnification of these compounds in both fresh and marine water and terrestrial food webs. Estimated biomagnification factors suggest biomagnification in predator-prey pairs, for example bird-fish and fish-invertebrates. Ecotoxicological data and preliminary environmental assessment of the risk of UV filters are also included and discussed.

Gago-Ferrero P; Díaz-Cruz MS; Barceló D

2012-11-01

142

Acute and chronic aquatic toxicity of ammonium perfluorooctanoate (APFO) to freshwater organisms.  

UK PubMed Central (United Kingdom)

Recent concerns have been raised concerning the widespread distribution of perfluorinated compounds in environmental matrices and biota. The compounds of interest include ammonium perfluorooctanoate (APFO, the ammonium salt of perfluorooctanoic acid, PFOA). APFO is used primarily as a processing aid in the production of fluoropolymers and fluoroelastomers. The environmental presence of perfluorooctanoate (PFO(-), the anion of APFO) and its entry into the environment as APFO make quality aquatic toxicity data necessary to assess the aquatic hazard and risk of APFO. We conducted acute and chronic freshwater aquatic toxicity studies with algae, Pseudokirchneriella subcapitata, the water flea, Daphnia magna, and embryo-larval rainbow trout, Oncorhynchus mykiss, using OECD test guidelines and a single, well-characterized sample of APFO. Acute 48-96 h LC/EC(50) values were greater than 400mg/l APFO and the lowest chronic NOEC was 12.5mg/l for inhibition of the growth rate and biomass of the freshwater alga. Un-ionized ammonia was calculated to be a potential significant contributor to the observed toxicity of APFO. Based on environmental concentrations of PFO(-) from various aquatic ecosystems, the PNEC value from this study, and unionized ammonia contributions to observed toxicity, APFO demonstrates little or no risk for acute or chronic toxicity to freshwater and marine aquatic organisms at relevant environmental concentrations.

Colombo I; de Wolf W; Thompson RS; Farrar DG; Hoke RA; L'Haridon J

2008-11-01

143

Incipient toxicity of lithium to freshwater organisms representing a salmonid habitat  

Energy Technology Data Exchange (ETDEWEB)

Because the eventual development of fusion power reactors could increase the mining, use and disposal of lithium five-fold by the year 2000, potential effects from unusual amounts of lithium in aquatic environments were investigated. Freshwater oganisms representing a Pacific Northwest salmonid habitat were exposed to elevated conentrations of lithium. Nine parameters were used to determine the incipient toxicity of lithium to rainbow trout (Salmo gairdneri), insect larvae (Chironomus sp.), and Columbia River periphyton. All three groups of biota were incipiently sensitive to lithium at concentrations ranging between 0.1 and 1 mg/L. These results correspond with the incipient toxicity of beryllium, a chemically similar component of fusion reactor cores. A maximum lithium concentration of 0.01 mg/L occurs naturally in most freshwater environments (beryllium is rarer). Therefore, a concentration range of 0.01 to 0.1 mg/L may be regarded as approaching toxic concentrations when assessing the hazards of lithium in freshwaters.

Emery, R.; Klopfer, D.C.; Skalski, J.R.

1981-07-01

144

Effects of pollution on freshwater organisms  

Energy Technology Data Exchange (ETDEWEB)

This review includes subjects in last year's reviews on effects of pollution on freshwater invertebrates and effects of pollution on freshwater fish and amphibians. This review also includes information on the effects of pollution on freshwater plants. 625 references.

Phipps, G.L.; Harden, M.J.; Leonard, E.N.; Roush, T.H; Spehar, D.L.; Stephan, C.E.; Pickering, Q.H.; Buikema, A.L. Jr.

1984-06-01

145

Modelling potential impacts of effective dispersant use on aquatic biota  

International Nuclear Information System (INIS)

Oil spill transport and fate modelling was used to evaluate maximum potential water column hydrocarbon concentrations with dispersant use. Oil spill modelling was performed with SIMAP, and used wind data, current data, and transport and weathering algorithms to calculate the mass of oil components in various environmental compartments; oil pathway over time; surface oil distribution; and concentrations of the oil components in water and sediments. Simulations assuming no dispersant use were compared to simulations where dispersant was applied after 8 or 16 hours of weathering for 2 wind conditions. With 2.5 m/s winds and no dispersant, the concentration plume was relatively small and short-lived. In 7.5 m/s winds, natural dispersion was considerable, and the application of dispersant at 80 per cent efficiency during the same wind conditions increased the volume affected by a factor of 4-6. In 2.5 m/s winds, dispersant use at 80 per cent efficiencies decreased the water volume affected proportionately. Results indicated that the highest water column impacts occurred when chemical dispersant was applied under light wind conditions where dilution was relatively slow. For the oil volume examined and assuming no dispersant use, wildlife impacts would occur on the scale of 100s km2, whereas water column effects with dispersant use in a worst case scenario would occur on the scale of 1 km2 in the upper mixed layer. An exception to the support of dispersant use would be if sensitive water column biota are present in the area of the slick. The conclusions applied to unconfined water bodies that were at least 10 metres deep. 18 refs., 4 tabs., 5 figs.

2006-01-01

146

Marine biota sightings during 3D marine seismic surveys  

Energy Technology Data Exchange (ETDEWEB)

This work intends to make a correlation between the presence of the marine biota and the seismic source activity (air guns) during seismic surveys, in Campos (BM-C-25 and BM-C-16) and Santos (BM-S-3) Basin, since July 2003 until March 2004. Environmental data were acquired onboard of the Seismic Vessel CGG Harmattan by a team of four oceanographers (environmental technicians), working on the highest place of the Vessel to record and identify the animals whenever was possible. The data were recorded in forms where fields about the biotic and environmental aspects were filled. In 212 days of observations, 2580,1 hours of sighting's effort were recorded; the air guns worked during 37,6% of the time of the effort. These efforts were made during the daylight reaching an average value of 11,35 hours/day. Sightings were divided into the suborders Odontocetes and Mysticetes, and others (fishes, turtles and non identified mammals). 175 sightings were recorded, being 54% when the air gun was off (24% Mysticetes, 56% Odontocetes, 20% others). Similarly, when the air gun was working, 46% of the records were made (24% Mysticetes, 61% Odontocetes, 6% others); the major concentration (58%) of individuals was inside the 1000 m radius around the ship, followed by 14% of the individuals occurring between 3001-4000 m radius away from the ship. The analysis of the data suggests a non-evasive behavior related to the working of the seismic source, corroborating the results reached by other publications using the data collected onboard CGG Vessels. (author)

Oliveira, Joao Luiz Martinez de; Uller, George A. [CGG do Brasil, Rio de Janeiro, RJ (Brazil); Derntl, Jose Renato; Ribeiro, Camila Castroviejo da Silva; Pereira, Edisio [GEOCOOP Cooperativa de Trabalho, Rio de Janeiro, RJ (Brazil); Miranda, Cristina Maschio de [Nautilus Cooperativa de Trabalho (Brazil); Ferraz, Alexandre Almeida; Costa, Leandro Damiao Soares da [Okeanos Consultoria e Meio Ambiente Ltda. (Brazil)

2004-07-01

147

Adiciones a la Biota de Uredinales (fungi) de Colombia/ Addictions to the Uredinales Biota (fungi) in Colombia  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Colecciones de plantas con síntomas de hongos royas (Uredinales, Basidiomycota) realizadas en los últimos años en los departamentos de Amazonas, Antioquia, Caldas, Cundinamarca, Tolima y Valle del Cauca han sido estudiadas y depositadas en el Museo Micológico de la Universidad Nacional de Colombia, Sede Medellín (MMUNM). Entre las novedades encontradas, se registran por primera vez para Colombia las royas: Puccinia investita, Sphenospora pallida, Crossopsora piperis, (more) Uredo psychotriicola y Pucciniosira solani. Se adiciona la familia botánica Dioscoreaceae para la Biota de Uredinales colombianos. Se hace la corrección del nombre anamórfico Uredo parthenii publicado para Colombia en 2003, por el nombre teliomorfico válido Puccinia schileana. Son registrados seis nuevos hospedantes parasitados por royas en Colombia, entre estos reviste importancia la colección sobre Origanum vulgare L. una planta aromática y medicinal cultivada mundialmente. Abstract in english Plant collections with symptoms of rusts fungi (Uredinales, Basidiomycota) made during recent years in provinces of Amazonas, Antioquia, Caldas, Cundinamarca, Tolima and Valle del Cauca have been studied and deposited in Museo Micológico of Universidad Nacional de Colombia, Sede Medellín (MMUNM). The rusts species Puccinia investita, Sphenospora pallida, Crossopsora piperis, Uredo psychotriicola and Pucciniosira solani are new records for Colombia. A first record for th (more) is country of rust fungi in plants of family Dioscoreaceae has been also made. The anamorphic name Uredo parthenii published in 2003 in Colombia, has been corrected by the valid teleomorph Puccinia schileana. Finally, six new hosts parasitized by rusts are recorded, including Origanum vulgare L. a world-wide important aromatic and medicinal plant.

Vanegas Berrouet, Katherin Maritza; Salazar Yepes, Mauricio

2011-12-01

148

Sulfate reduction in freshwater peatlands.  

Science.gov (United States)

This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the ...

M. Oequist

1996-01-01

149

Nearctic freshwater tardigrades: a review  

Directory of Open Access Journals (Sweden)

Full Text Available The distribution and ecology of limno-terrestrial Tardigrada in the Nearctic realm remain poorly known. This is especially true of freshwater tardigrades (i.e., species found in permanently submerged habitats), which have received much less attention than terrestrial species. We reviewed the literature on Nearctic freshwater tardigrades. Of 204 Nearctic limno-terrestrial tardigrade species, 44 have been collected from sediments and aquatic vegetation of streams, rivers, ponds, lakes, groundwater and cryoconite holes. Of these, 17 are hydrophilous species found exclusively or primarily in aquatic environments. Most of the remainder are probably washed in accidentally from terrestrial substrates. Among the hydrophilous species, five are endemic to the Nearctic realm and three cosmopolitan. Hypsibius dujardini is the most widely-distributed hydrophilous species. There are no regional collections of Nearctic freshwater tardigrades comparable to those for terrestrial species. Aquatic tardigrades are benthic, and are found in sediments and on aquatic vegetation. Hypsibius dujardini and other widespread species are found in both substrates, and there is thus no evidence of substrate specificity. Numerically, tardigrades usually comprise a minor component of benthic invertebrate communities. Nothing is known of their trophic relationships or dispersal in these habitats. The density of Nearctic freshwater tardigrade species peaks in the spring and/or fall. Future research should increase the spatial and temporal scale of study, and employ adequate replication.

Mitchell M. McFATTER; Harry A. MEYER; Juliana G. HINTON

2007-01-01

150

Nearctic freshwater tardigrades: a review  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The distribution and ecology of limno-terrestrial Tardigrada in the Nearctic realm remain poorly known. This is especially true of freshwater tardigrades (i.e., species found in permanently submerged habitats), which have received much less attention than terrestrial species. We reviewed the literat...

Mitchell M. McFATTER; Harry A. MEYER; Juliana G. HINTON

151

Background and anthropogenic radionuclide derived dose rates to freshwater ecosystem - Nuclear power plant cooling pond - Reference organisms  

International Nuclear Information System (INIS)

The radiological assessment of non-human biota to demonstrate protection is now accepted by a number of international and national bodies. Therefore, it is necessary to develop a scientific basis to assess and evaluate exposure of biota to ionizing radiation. Radionuclides from the Ignalina Nuclear Power Plant (Lithuania) were discharged into Lake Druksiai cooling pond. Additional radionuclide migration and recharge to this lake from a hypothetical near-surface, low-level radioactive waste disposal, to be situated 1.5 km from the lake, had been simulated using RESRAD-OFFSITE code. This paper uses ERICA Integrated Approach with associated tools and databases to compare the radiological dose to freshwater reference organisms. Based on these data, it can be concluded that background dose rates to non-human biota in Lake Druksiai far exceed those attributable to anthropogenic radionuclides. With respect the fishery and corresponding annual committed effective human dose as a result of this fish consumption Lake Druksiai continues to be a high-productivity water body with intensive angling and possible commercial fishing. - Highlights: ? Dose rates to the reference organisms are lower than expected from the background radioactivity. ? Pelagic fish part of adult human annual committed effective dose would be as small as a few ?Sv y-1. ? With respect the fishery Lake Druksiai continues to be a high-productivity water body.

2011-01-01

152

Deriving freshwater quality criteria for copper, cadmium, aluminum and manganese for protection of aquatic life in Malaysia.  

UK PubMed Central (United Kingdom)

Freshwater quality criteria for copper (Cu), cadmium (Cd), aluminum (Al), and manganese (Mn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia, which were Macrobrachiumlanchesteri (prawn), two fish -Poeciliareticulata and Rasborasumatrana, Melanoidestuberculata (snail), Stenocyprismajor (ostracod), Chironomusjavanus (midge larvae), Naiselinguis (annelid), and Duttaphrynusmelanostictus (tadpole), to determine 96-h LC50 values for Cu, Cd, Al, and Mn. The final acute values (FAVs) for Cu, Cd, Al, and Mn were 2.5, 3.0, 977.8, and 78.3 ?gL(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a Criterion Maximum Concentration (CMC) and a criterion Continuous Concentration (CCC) for Cu, Cd, Al, and Mn of 1.3, 1.5, 488.9, and 39.1 ?gL(-1) and 0.3, 0.36, 117.8, and 9.4 ?gL(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Cu, Cd, Al, and Mn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that R.sumatrana, M.lanchesteri, C.javanus, and N.elinguis were the most sensitive to Cu, Cd, Al, and Mn, respectively.

Shuhaimi-Othman M; Nadzifah Y; Nur-Amalina R; Umirah NS

2013-03-01

153

Dissolved Organic Matter in Freshwaters  

Science.gov (United States)

Organic matter in freshwaters exists as dissolved molecules, colloids, and particles. It is appropriate to regard these distinctions as dynamic, however, because organic matter can be interconverted readily between these forms by dissolution and precipitation, sorption and desorption, aggregation and disaggregation, etc. Dissolved organic matter (DOM), the subject of this chapter, is defined operationally as the fraction of organic matter in a water sample that passes through a 0.45 ?m filter. In the authors' opinion, the scientific literature on organic matter in freshwaters will be better reflected in this review, if data are considered without regard to the manner in which water samples may have been filtered. This more general approach is warranted because: * many submicron colloids and some microorganisms can pass through 0.45 ?m filters; * the effective pore size of a 0.45 ?m filter is usually unknown, because it is decreased by partial clogging during the filtration of a water sample; * some important studies have been conducted on unfiltered samples or on samples that were filtered through other types of filters; and * some important studies have been conducted on samples that were concentrated with ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) membranes.As methods for fractionation and isolation of organic matter in freshwaters have evolved, and as the intensity of research has waxed and waned in various academic disciplines, a rich and potentially confusing nomenclature has evolved for organic matter in freshwaters. Some of the more commonly encountered descriptors and their associated acronyms, if any, are yellow organic acids (YOAs), aquatic humus, DOM, and natural organic matter (NOM). Regardless of the terminology used in the original literature, the organic matter in freshwaters is referred to as DOM in this review, except when it is necessary to be more specific.

Perdue, E. M.; Ritchie, J. D.

2003-12-01

154

Studies on the estimation of radiation dose to typical non human biota around Kaiga nuclear power plant  

International Nuclear Information System (INIS)

It is necessary to prove exclusively that biota is sufficiently protected from ionizing radiation since pathway leading to biota exposure is quite different compared to that for human being and non human biota has access to contaminated areas while human access is limited. The radiation from purely natural sources may be a useful benchmark since radiation at these levels is tolerated by biota. This paper presents the estimation of radiation dose to typical members of biota around Kaiga site, which includes a herbivorous mammalian species (cow), one avio fauna (pigeon), one burrowing animal (earthworm) and an aquatic animal (fish). The internal and external doses to species from naturally occurring radio nuclides were evaluated from concentrations of radio nuclides in soil, air, water and dietary items and the relevant concentration factors. An attempt is made for the evaluation of dose to above biota from reactor originated radio nuclides. The study identifies the most significant radionuclide, most significant pathway leading to radiological risk to member of biota from natural sources and reactor-produced radionuclides. From the computed dose to biota per unit release from reactor, study identifies the significant radionuclide and pathways for reactor produced radionuclides. The study conclusively proves that biota dose from reactor produced radionuclides from KGS is negligible. (author)

2008-01-01

155

Toxicity of soil iodine to terrestrial biota, with implications for 129I  

International Nuclear Information System (INIS)

The environmental impact of 129I has traditionally been assessed by its radiological effects on human health; however, protection of human health does not ensure protection of other biota. Because of the very long half-life of 129I, there is a relatively high molar concentration of I associated with any specified level of radioactivity. The potential exists for chemical toxicity to non-human biota to exceed radiological toxicity in importance. The authors reviewed the literature and conducted laboratory bioassays to obtain information on the chemical toxicity of inorganic I to terrestrial biota. Levels as low as 5 mg I kg-1 soil may have detrimental effects. If this were as 129I, the corresponding radiological effects to non-human biota may not be as important as the chemical toxicity. However, because of the very low risk factor applied to protect humans, levels of 129I in the environment acceptable for human health appear to be acceptable for other biota at the higher risk levels commonly used for them. (author).

1995-01-01

156

Do laboratory salinity tolerances of freshwater animals correspond with their field salinity?  

Energy Technology Data Exchange (ETDEWEB)

The degree to which laboratory derived measures of salinity tolerance reflect the field distributions of freshwater biota is uncertain. In this paper we compare laboratory-derived acute salinity tolerance (LC{sub 50} values) of freshwater macroinvertebrates (range 5.5-76 mS/cm) and fish (range 2.7-82 mS/cm) from southeastern Australia with the salinity from which they have been collected in the field. Only 4% of the macroinvertebrates were collected at salinity levels substantially higher than their 72-h LC{sub 50} obtained from directly transferring animals from low salinity water to the water they were tested (direct transfer LC{sub 50}). This LC{sub 50} value was correlated with the maximum salinity at which a species had been collected. For common macroinvertebrates, the maximum field salinity was approximated by the direct transfer 72-h LC{sub 50}. For adult freshwater fish, 21% of species were collected at salinities substantially greater than their acute direct transfer LC{sub 50} and there was a weak relationship between these two variables. Although there was a weak correlation between the direct transfer LC{sub 50} of early life stages of freshwater fish and the maximum field salinity, 58% of the field distribution were in higher than their LC{sub 50} values. In contrast, LC{sub 50} determined from experiments that acclimated adult fish to higher salinity (slow acclimation) provided a better indication of the field distribution: with only one fish species (7%) being in conflict with their maximum field salinity and a strong positive relationship between these variables. This study shows that laboratory measures of acute salinity tolerance can reflect the maximum salinity that macroinvertebrate and fish species inhabit and are consistent with some anecdotal observations from other studies. - Acute laboratory salinity tolerances relate to maximum salinity where organisms occur in nature.

Kefford, Ben J.; Papas, Phil J.; Metzeling, Leon; Nugegoda, Dayanthi

2004-06-01

157

Do laboratory salinity tolerances of freshwater animals correspond with their field salinity?  

International Nuclear Information System (INIS)

[en] The degree to which laboratory derived measures of salinity tolerance reflect the field distributions of freshwater biota is uncertain. In this paper we compare laboratory-derived acute salinity tolerance (LC50 values) of freshwater macroinvertebrates (range 5.5-76 mS/cm) and fish (range 2.7-82 mS/cm) from southeastern Australia with the salinity from which they have been collected in the field. Only 4% of the macroinvertebrates were collected at salinity levels substantially higher than their 72-h LC50 obtained from directly transferring animals from low salinity water to the water they were tested (direct transfer LC50). This LC50 value was correlated with the maximum salinity at which a species had been collected. For common macroinvertebrates, the maximum field salinity was approximated by the direct transfer 72-h LC50. For adult freshwater fish, 21% of species were collected at salinities substantially greater than their acute direct transfer LC50 and there was a weak relationship between these two variables. Although there was a weak correlation between the direct transfer LC50 of early life stages of freshwater fish and the maximum field salinity, 58% of the field distribution were in higher than their LC50 values. In contrast, LC50 determined from experiments that acclimated adult fish to higher salinity (slow acclimation) provided a better indication of the field distribution: with only one fish species (7%) being in conflict with their maximum field salinity and a strong positive relationship between these variables. This study shows that laboratory measures of acute salinity tolerance can reflect the maximum salinity that macroinvertebrate and fish species inhabit and are consistent with some anecdotal observations from other studies. - Acute laboratory salinity tolerances relate to maximum salinity where organisms occur in nature

2004-01-01

158

Comparative food-chain behavior and distribution of actinide elements in and around a contaminated fresh-water pond  

International Nuclear Information System (INIS)

The bioaccumulation of 233 234U, 238U, 238Pu, 239 240Pu, 241Am, and 244Cm in both native and introduced biota was studied at Pond 3513, a former low-level radioactive waste settling basin at Oak Ridge National Laboratory. This system, which was decommissioned in 1976 after more than 30 years use, contains approximately 5 Ci of 239 240Pu; inventories of other actinide isotopes are considerably less. Significantly higher concentrations of actinides in fish that were allowed access to sediments indicated that sedimentary particulates may be the primary source of transuranics to biota in shallow fresh-water ecosystems. Our study determined habitat, in particular the degree of association of an organism with the sediment-water interface, to be the primary factor in controlling transuranic concentrations in aquatic biota. In most of the biological samples analyzed, excluding samples suspected of being contaminated by sediment, 241Am/239Pu, 244Cm/239Pu, and 238U/239Pu ratios were greater than the respective ratio in sediment while 233 234U/238U, and 239 240Pu/238Pu ratios were not different from the respective ratios in sediment. The relative uptake of actinides from contaminated sediment by aquatic and terrestrial biota at this site was U > Cm greater than or equal to Am > Pu. The relative extractability of actinides from shoreline sediment was U > Cm approx. = Am > Pu; we also observed the same relative ranking for sediment-water exchange in situ. Concentrations of transuranics in water, terrestrial vegetation, and vertebrate carcasses were less than 10% of the recommended public exposure maximum permissible concentration (MPC) of the ICRP.

1981-07-31

159

Monitoring of perfluorinated compounds in aquatic biota: an updated review.  

UK PubMed Central (United Kingdom)

The goal of this article is to summarize new biological monitoring information on perfluorinated compounds (PFCs) in aquatic ecosystems (post-2005) as a followup to our critical review published in 2006. A wider range of geographical locations (e.g., South America, Russia, Antarctica) and habitats (e.g., high-mountain lakes, deep-ocean, and offshore waters) have been investigated in recent years enabling a better understanding of the global distribution of PFCs in aquatic organisms. High concentrations of PFCs continue to be detected in invertebrates, fish, reptiles, and marine mammals worldwide. Perfluorooctane sulfonate (PFOS) is still the predominant PFC detected (mean concentrations up to 1900 ng/g ww) in addition to important concentrations of long-chain perfluoroalkyl carboxylates (PFCAs; sum PFCAs up to 400 ng/g ww). More studies have evaluated the bioaccumulation and biomagnification of these compounds in both freshwater and marine food webs. Several reports have indicated a decrease in PFOS levels over time in contrast to PFCA concentrations that have tended to increase in tissues of aquatic organisms at many locations. The detection of precursor metabolites and isomers has become more frequently reported in environmental assessments yielding important information on the sources and distribution of these contaminants. The integration of environmental/ecological characteristics (e.g., latitude/longitude, salinity, and/or trophic status at sampling locations) and biological variables (e.g., age, gender, life cycle, migration, diet composition, growth rate, food chain length, metabolism, and elimination) are essential elements in order to adequately study the environmental fate and distribution of PFCs and should be more frequently considered in study design.

Houde M; De Silva AO; Muir DC; Letcher RJ

2011-10-01

160

Evolution of growth by genetic accommodation in Icelandic freshwater stickleback.  

UK PubMed Central (United Kingdom)

Classical Darwinian adaptation to a change in environment can ensue when selection favours beneficial genetic variation. How plastic trait responses to new conditions affect this process depends on how plasticity reveals to selection the influence of genotype on phenotype. Genetic accommodation theory predicts that evolutionary rate may sharply increase when a new environment induces plastic responses and selects on sufficient genetic variation in those responses to produce an immediate evolutionary response, but natural examples are rare. In Iceland, marine threespine stickleback that have colonized freshwater habitats have evolved more rapid individual growth. Heritable variation in growth is greater for marine full-siblings reared at low versus high salinity, and genetic variation exists in plastic growth responses to low salinity. In fish from recently founded freshwater populations reared at low salinity, the plastic response was strongly correlated with growth. Plasticity and growth were not correlated in full-siblings reared at high salinity nor in marine fish at either salinity. In well-adapted lake populations, rapid growth evolved jointly with stronger plastic responses to low salinity and the persistence of strong plastic responses indicates that growth is not genetically assimilated. Thus, beneficial plastic growth responses to low salinity have both guided and evolved along with rapid growth as stickleback adapted to freshwater.

Robinson BW

2013-01-01

 
 
 
 
161

Environmental assessment for Bruce Restart: calculating doses to non-human biota  

International Nuclear Information System (INIS)

An environmental assessment of returning Units 1 and 2 of Bruce A nuclear generating station to service from their temporary lay-up was carried out in 2005 and should be completed by mid-2006. It included an assessment of effects of environmental concentrations of radionuclides on aquatic and terrestrial biota. A method of assessing doses to individual species of biota using data available for reference organisms was applied to conduct this assessment. This method is consistent with the draft proposals published by ICRP in November 2005. Even though the regulatory bodies and scientific community have not achieved a full consensus on the regulatory limits on, or methodology for assessing doses to, biota, this paper demonstrates that a practical approach based on most recent research can be used successfully for the purposes of environmental assessments. (author)

2006-01-01

162

K-BIOTA: A Computer Program for Assessing Radiation Doses to Non-human Species  

International Nuclear Information System (INIS)

Recently, the Internal Commission on Radiological Protection (ICRP) stressed the importance of the environmental protection from the ionizing radiation and subsequently proposed the reference animal and plant (RAPs) concept, and the methodology to evaluate non-human species radiation dose. In order to apply an integrated methodology of addressing the international recent issue for the protection of the environment from the ionizing radiation to the Korean ecological environment, the K-BIOTA, a computer program for assessing radiation doses to non-human species, is presently being developed. This paper describes the components and methodologies that are considered in the K-BIOTA

2010-01-01

163

Freshwater bacterial lifestyles inferred from comparative genomics.  

UK PubMed Central (United Kingdom)

While micro-organisms actively mediate and participate in freshwater ecosystem services, we know little about freshwater microbial genetic diversity. Genome sequences are available for many bacteria from the human microbiome and the ocean (over 800 and 200, respectively), but only two freshwater genomes are currently available: the streamlined genomes of Polynucleobacter necessarius ssp. asymbioticus and the Actinobacterium AcI-B1. Here, we sequenced and analysed draft genomes of eight phylogentically diverse freshwater bacteria exhibiting a range of lifestyle characteristics. Comparative genomics of these bacteria reveals putative freshwater bacterial lifestyles based on differences in predicted growth rate, capability to respond to environmental stimuli and diversity of useable carbon substrates. Our conceptual model based on these genomic characteristics provides a foundation on which further ecophysiological and genomic studies can be built. In addition, these genomes greatly expand the diversity of existing genomic context for future studies on the ecology and genetics of freshwater bacteria.

Livermore JA; Emrich SJ; Tan J; Jones SE

2013-06-01

164

Panbiogeographical analysis of Costa Rican freshwater fishes  

Directory of Open Access Journals (Sweden)

Full Text Available Track analysis and Parsimony analysis of endemicity (PAE) were performed to analyze the distribution pattern of Costa Rican freshwater fishes. A basic matrix (presence/absence) was prepared using the distribution of 77 freshwater fish. The data were analyzed with CLIQUE software in order to find generalized tracks (cliques). Data also were analyzed with the software NONA and Winclada version 1.00.08 in order to perform the Parsimony Analysis of Endemicity (PAE). Fourteen equally probable cliques were found with 31 species in each and the intersection of the amount was selected as a generalized track dividing the country in two main zones: Atlantic slope from Matina to Lake Nicaragua and Pacific slope from the Coto River to the basin of the Tempisque River connected with some branches oriented to the central part of the country. PAE analysis found ten cladogram areas (72 steps, CI=0.45, RI=0.64), using the "strict consensus option" two grouping zones were identified: Atlantic slope and Pacific slope. Both PAE and Track Analysis show the division of the two slopes and the orientation of the generalized track suggests new biogeographical evidence on the influence of both old and new southern elements to explain the migrations of freshwater fish into Central America during two different geological events. Rev. Biol. Trop. 56 (1): 165-170. Epub 2008 March 31.Con el objetivo de analizar el patrón de distribución de peces de agua dulce de Costa Rica se aplicó un análisis de trazos y de parsimonía de endemismos (PAE). Se construyó una matriz básica utilizando la distribución de 77 especies. Se utilizó el programa CLIQUE con la intención de encontrar los trazos generalizados y NONA y Winclada, versión 1.00.08, con el fin de llevar a cabo el PAE. Se encontró un total de 14 cliques igualmente probables con 31 especies. De esta cantidad se construyó un trazo generalizado que constituye la intersección del total, dividiendo el país en dos zonas: Atlántico, desde Matina hasta el Lago de Nicaragua y Pacífico desde el río Coto hasta el río Tempisque conectado con la región central del país. El PAE encontró diez cladogramas de áreas (72 pasos, CI=0.45, RI=0.64), cuyo consenso estricto identificó dos zonas de agrupamiento: Atlántico y Pacífico. Ambos análisis muestran la división entre las dos vertientes y la orientación de los trazos generalizados sugiere nueva evidencia de la influencia biogeográfica de los denominados elementos de migración antiguo y nuevo del sur, los cuales se habían sugerido empíricamente en el pasado para explicar las migraciones hacia Centroamérica en dos periodos geológicos diferentes.

Jonathan Herrera-Vásquez; William Bussing; Federico Villalobos

2008-01-01

165

Soil and freshwater nematodes of the Iberian fauna: A synthesis  

Directory of Open Access Journals (Sweden)

Full Text Available The first available compilation of Iberian soil and freshwater nematodes is presented in this paper. The inventory is currently made up of 981 species belonging to 236 genera, 77 families and 12 orders. Data of the Iberian nematode fauna are compared with other components of the Iberian biota, as well as the nematode fauna of other geographical regions. Quantitative and qualitative aspects of the nematode inventory are analyzed and discussed, paying special attention to the kind of information available for each species, and concluding that practically one-third of Iberian species are deficiently characterized and need further study. Endemicity of Iberian species is also considered: 143 species, 14.6% of the total, are restricted (in their distribution) to the Iberian geography, most of them being members of the orders Dorylaimida (87) and Tylenchida (29), which are also the most diversified nematode taxa. Practical or applied interest of knowledge of the Iberian nematode fauna is commented and supported with examples and recent contributions. Finally, an alphabetical list of the species, ordered by specific name, is provided.En esta contribución se presenta una recopilación de las especies ibéricas de nematodos de suelo y de agua dulce, la primera de este tipo realizada hasta el momento. El inventario actual lo componen 981 especies de 236 géneros, 77 familias y 12 órdenes. Los datos correspondiente a la fauna ibérica de nematodos se compara con la de otros táxones de la biota ibérica. Se analizan y se discuten distintos aspectos cuantitativos y cualitativos de la fauna nematológica, con especial énfasis en el tipo de información disponible sobre cada especie, y se concluye que casi una tercera parte de las especies ibéricas permanecen insuficientemente caracterizadas, razón por la cual requieren de estudios adicionales. La endemicidad de las especies es así mismo objeto de atención: 143 especies, un 14.6% del total están restringidas en su distribución al ámbito ibérico, en su mayor parte pertenecientes a los órdenes Dorylaimida (87) y Tylenchida (29), por otra parte los más diversificados de entre los pertenecientes al filo. El interés básico y aplicado del conocimiento de la fauna de nematodos es comentado e ilustrado con aportaciones recientes y ejemplos. Por último, se presenta una lista de todas las especies de la fauna ibérica, ordenadas alfabéticamente por su epíteto específico.

Peña-Santiago, R.; Abolafia, J.; Guerrero, P.; Liébanas, G.; Peralta, M.

2006-01-01

166

A meta-analysis of responses of soil biota to global change.  

UK PubMed Central (United Kingdom)

Global environmental changes are expected to impact the abundance of plants and animals aboveground, but comparably little is known about the responses of belowground organisms. Using meta-analysis, we synthesized results from over 75 manipulative experiments in order to test for patterns in the effects of elevated CO(2), warming, and altered precipitation on the abundance of soil biota related to taxonomy, body size, feeding habits, ecosystem type, local climate, treatment magnitude and duration, and greenhouse CO(2) enrichment. We found that the positive effect size of elevated CO(2) on the abundance of soil biota diminished with time, whereas the negative effect size of warming and positive effect size of precipitation intensified with time. Trophic group, body size, and experimental approaches best explained the responses of soil biota to elevated CO(2), whereas local climate and ecosystem type best explained responses to warming and altered precipitation. The abundance of microflora and microfauna, and particularly detritivores, increased with elevated CO(2), indicative of microbial C limitation under ambient CO(2). However, the effects of CO(2) were smaller in field studies than in greenhouse studies and were not significant for higher trophic levels. Effects of warming did not depend on taxon or body size, but reduced abundances were more likely to occur at the colder and drier sites. Precipitation limited all taxa and trophic groups, particularly in forest ecosystems. Our meta-analysis suggests that the responses of soil biota to global change are predictable and unique for each global change factor.

Blankinship JC; Niklaus PA; Hungate BA

2011-03-01

167

New occurence of the Cambrian (Stage 4, Series 2) Guanshan Biota in Huize, Yunnan, South China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Typical elements of the Guanshan Biota are reported from the Cambrian Stage 4 Wulongqing Formation of Huize, Qujing, South China, approximately 100 km north of the Guanshan fossil sites previously reported. Lithostratigraphy and biostratigraphy of the current Zhujiaqing section are also discussed he...

Liu J N; Ou Q; Han J; Zhang Z F; He T J; Yao X Y; Fu D J; Shu D G

168

Assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya  

International Nuclear Information System (INIS)

A radiation dose assessment exercise was carried out for the edible biota Solanum nigrum, Carica papaya, Raphnus sativum and Phaseolus domesticus due to naturally available radionuclides 40K, 238U and 232Th in the Domiasiat area in Meghalaya (India)). The concentration of radionuclides in biota and corresponding soil was measured by the NaI(Tl) detector having a minimum detection limit (efficiency, 32.4 %) and machine counting time of 3000 s. The obtained transfer factor for 40K was 0.3061, 0.7163, 0.1988 and 0.1279, for 232Th 0.0003, 2.22 E-05, 2.71 E-05 and 3.45 E-05 and for 238U 1.46 E-05, 9.73 E-05, 1.46 E-05 and 3.11 E-05 (ratio) in each biota, respectively. The detailed physiological and morphological study of the biota was carried out. The point source dose distribution (sourcetarget) hypothesis was applied for the radiation absorbed fraction. The generated data were modelled using FASSET and obtained un-weighted total dose was 1.78 E-04, 6.84 E-03, 8.46 E-03 and 1.73 E-04?Gy h-1, respectively, finally compared with the IAEA and UNSCEAR data set for screening level dose risk assessment. (authors)

2008-01-01

169

ENANTIOMERIC OCCURRENCE AND DISTRIBUTION OF CHIRAL ORGANOCHLORINE COMPOUNDS IN U.S. RIVER SEDIMENT AND BIOTA  

Science.gov (United States)

River sediment and biota (fish, bivalves) from throughout the continental U.S. were analyzed for chiral organochlorine compounds (o,p'-DDT and DDD, some chlordane compounds, PCB atropisomers) to assess spatial trends in environmental chirality. Chiral PCB enantiomers were racemic...

170

Comparison of freshwater discrimination ability in three species of sea kraits (Laticauda semifasciata, L. laticaudata and L. colubrina).  

UK PubMed Central (United Kingdom)

Three species of amphibious sea kraits (Laticauda spp.) require drinking freshwater to regulate water balance. The extent of terrestriality is known to differ among them. Species with higher extent of terrestriality would drink freshwater accumulated on land, whereas less terrestrial species would rely totally on freshwater that runs into the sea. Consequently, we predicted that the latter species might have a better ability to follow the flow of freshwater or lower salinity water in the sea than the former. We investigated the freshwater discrimination ability of three sea krait species, using a Y-maze apparatus. We found that Laticauda semifasciata and Laticauda laticaudata, less terrestrial species, followed freshwater significantly more frequently than seawater, whereas Laticauda colubrina, more terrestrial species, unbiasedly selected freshwater and seawater. This result supports our prediction and suggests that less terrestrial sea kraits more efficiently access freshwater sources in the sea than highly terrestrial sea kraits. It is likely that behavioral rehydration systems vary among sea kraits in relation to their terrestrial tendency.

Kidera N; Mori A; Tu MC

2013-03-01

171

Temporal changes in radionuclide transfer to biota in Canadian shields lakes receiving chronic inputs  

International Nuclear Information System (INIS)

Changes in environmental contaminant levels are often assessed using non-human biota as bio-monitors, due to their ability to accumulate trace elements found at low levels in natural systems over time. This is often accomplished through direct comparisons of contaminant concentrations in indicator species with those present in surface waters, in the form of transfer factors; however, transfer factors can vary by orders of magnitude between species, between systems, and possibly within systems. In addition, transfer factors are applied under a steady state assumption, whereby the relationship between contaminant concentrations in biota tissues and concentrations in abiotic media in the surrounding environment are assumed constant through space and time. As a result, quantification of changes in transfer factors of contaminants, such as radionuclides, in aquatic systems receiving chronic inputs will provide useful insight as to whether variability in transfer factors is related to changes in contaminant fluxes through a lake. Perch Lake (Chalk River, Ontario) represents an ideal system to address such issues, since it has received chronic inputs of 60Co, 137Cs, 90Sr, and 3H that have been changing over a 40 to 50 year period. Changes in transfer of these radionuclides to biota have, therefore, been compared with changes in radionuclide source terms over time. In general, with few exceptions, radionuclide transfer factors were fairly consistent over this period, as indicated by strong correlations between measured and estimated values. This conclusion was further strengthened by comparing radionuclide transfer factors measured in Perch Lake biota relative to those reported for other Canadian Shield lakes, which showed similar values. Based on findings for these radionuclides, it is appropriate to apply generic transfer factors to estimate levels in aquatic biota based on concentrations in surface waters of Canadian Shield lakes. (author)

2004-01-01

172

DEGRADATION AND RECOVERY OF BIOTA IN ERODED CHERNOZEMS OF THE REPUBLIC OF MOLDOVA  

Directory of Open Access Journals (Sweden)

Full Text Available The biota’s state of the ordinary chernozem located in the southern zone of the Republic of Moldova has been investigated. Arable chernozems with different degrees of erosion (slightly, moderately and severely eroded) have been compared to the chernozem with the normal profile and eroded soil which was under 58 year’s old fallow. The biological degradation of soils occurred as a result of water erosion processes. The parameters of the biota very depending on the erosion degree and decrease in the following sequence: chernozem with the normal profile ? slightly eroded chernozem ? moderately eroded chernozem ? severely eroded chernozem. Losses of microbial carbon amount to 107-248, 305-433 and 513-535 kg C ha-1 according to the erosion degree. The loss of species and families of invertebrates in moderately and severely eroded chernozems is of 63 - 100%. Diversity of the Bacillus family decreased from 14 species to 7 - 10 species. The decline of enzymes activities in moderately and severely eroded chernozems reaches 29.2-55.6% for dehydrogenase and 85.7-94.3% for urease. A scale of biological parameters has been proposed to assess the stability of biota of the ordinary chernozem and to develop the national soil quality standards. The recovery rate of the biota and fertility of eroded arable chernozems that moved to the category of fallow soils has been determined. In this context, the management of fallow land areas has been recommended aiming to regenerate the edaphic fauna and microorganisms and to restore the natural quality of eroded chernozems.

Irina SENICOVSCAIA

2012-01-01

173

Aquatic Conservation: Marine and Freshwater Ecosystems ????????????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aquatic Conservation: Marine and Freshwater Ecosystems is an international journal dedicated to publishing original papers that relate specifically to freshwater, brackish or marine habitats and encouraging work that spans these ecosystems. This journal provides a forum in which all aspects o...

174

Risk assessment of residual DDTs in freshwater and marine fish cultivated around the Pearl River Delta, China.  

UK PubMed Central (United Kingdom)

Six species of freshwater fish collected from 10 fishponds in Shunde and Zhongshan, China, four species of marine fishes collected from different mariculture farms [four in Hong Kong (Tung Lung Chau, Ma Wan, Cheung Chau and Kat O) and two in mainland China (Daya Bay and Shenzhen)] together with feed (both trash fish and commercial pellets) and sediment were analyzed for DDTs. Total DDTs in freshwater fish flesh decreased in the order of: carnivores [1742 microg/kg lipid weight (l.w.)] > herbivores (165 microg/kg, l.w.) > omnivores (42.5 microg/kg, l.w.), with the highest concentration detected in mandarin fish (Siniperca chuatsi) (2641 microg/kg, l.w.). For marine fish, snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides) collected in Ma Wan contained elevated levels of total DDTs (2590 and 2034 microg/kg l.w., respectively). Trash fish used in both freshwater and marine fish farms contained significantly higher levels (86.5-641 microg/kg l.w.) (p < 0.05) of DDTs than in commercial pellets, but correlations between DDT levels in fish feed and muscle were not significant. The elevated biota-sediment accumulating factor for tilapia (Tilapia mossambicus) (24.1) indicated that accumulation of DDTs from sediment to the fish was evident. It can be concluded that trash fish should not be used for fish culture in order to lower the level of residual DDTs in fish muscle.

Leung SY; Kwok CK; Nie XP; Cheung KC; Wong MH

2010-02-01

175

The Trace Element Analysis in Freshwater Fish Species, Water and Sediment in Iyidere Stream (Rize-Turkey)  

Directory of Open Access Journals (Sweden)

Full Text Available Many environmental problems like dam construction, agricultural debris, flooding and industrial establishments threaten Iyidere stream (Rize, Turkey) on the southeastern coast of the Black Sea (Turkey). The trace element concentrations in water, fish and sediments in Iyidere stream (Rize, Turkey) were investigated in this study. The concentration of six different elements in ten freshwater fish species and sediment was determined using energy dispersive X-ray fluorescence method. A radioisotope excited X-ray fluorescence analysis using the method of multiple standard addition is applied for the elemental analysis of fish and sediments. Water samples for trace metals were analyzed using standard spectrophotometry methods. A qualitative analysis of spectral peaks showed that ten different freshwater fish samples (Chondrostoma colchicum, Chalcalburnus chalcoides, Salmo trutta labrax, Alburnoides bipunctatus, Leuciscus cephalus, Barbus taurus escherichia, Capoeta tinca, Neogobius kessleri, Rutilus frisii, Lampetra lanceolata) and sediment contained phosphorus (P), sulphur (S), chlorine (Cl), potassium (K), calcium (Ca) and titanium (Ti). Heavy metals as toxic elements for biota (Pb, Cd, Hg, Zn and Mn etc.) were not detected in fish, water and sediments. Thus, It can be declared that freshwater fish of Iyidere does not contains health risks for consumers in terms of metal pollution.

Bulent Verep; Cengiz Mutlu; Gokhan Apaydin; Ugur Cevik

2012-01-01

176

Productivity and salinity structuring of the microplankton revealed by comparative freshwater metagenomics.  

UK PubMed Central (United Kingdom)

Little is known about the diversity and structuring of freshwater microbial communities beyond the patterns revealed by tracing their distribution in the landscape with common taxonomic markers such as the ribosomal RNA. To address this gap in knowledge, metagenomes from temperate lakes were compared to selected marine metagenomes. Taxonomic analyses of rRNA genes in these freshwater metagenomes confirm the previously reported dominance of a limited subset of uncultured lineages of freshwater bacteria, whereas Archaea were rare. Diversification into marine and freshwater microbial lineages was also reflected in phylogenies of functional genes and there were also significant differences in functional beta-diversity. The pathways and functions that accounted for these differences are involved in osmoregulation, active transport, carbohydrate and amino acid metabolism. Moreover, predicted genes orthologous to active transporters and recalcitrant organic matter degradation were more common in microbial genomes from oligotrophic versus eutrophic lakes. This comparative metagenomic analysis allowed us to formulate a general hypothesis that oceanic- compared to freshwater-dwelling microorganisms, invest more in metabolism of amino acids and that strategies of carbohydrate metabolism differ significantly between marine and freshwater microbial communities.

Eiler A; Zaremba-Niedzwiedzka K; Garcia MM; McMahon KD; Stepanauskas R; Andersson SG; Bertilsson S

2013-10-01

177

The freshwater reservoir effect in radiocarbon dating  

DEFF Research Database (Denmark)

The freshwater reservoir effect can result in too high radiocarbon ages of samples from lakes and rivers, including the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. In my talk, I will explain the causes and consequences of this effect. Two case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany.

Philippsen, Bente

178

Mercury accumulation in biota of Thunder Creek, Saskatchewan  

Energy Technology Data Exchange (ETDEWEB)

Collection of biological organisms was undertaken to investigate the bioaccumulation of mercury in the food chain, the results of which are reported. Two sites were selected on Thunder Creek; the control or background site, site number 2, is located approximately 2.5 km upstream, from site number 1. The selection of organisms for analysis was based on the presence and abundance of each at both locations. Only crayfish (Orconcetes virilis) pearl dace (Semotilus margarita) and brook stickleback (Culaea inconstans) were found to be sufficiently abundant. The importance of the data obtained is the significant difference in concentration between the upstream and downstream sites on Thunder Creek. This difference shows that more mercury is available to the biological community at site number 1 than at site number 2 confirming that mercury in the contaminated sediments is being methylated and taken up into the food chain.

Munro, D.J.; Gummer, W.D.

1980-12-01

179

Potential kinetic availability of metals in sulphidic freshwater sediments  

International Nuclear Information System (INIS)

The insolubility of metal sulphides is believed to limit the bioavailability of trace metals in sulphidic sediments. However, if non-equilibrium conditions are important, metals may be more available than simple thermodynamic calculations suggest. To investigate the possible dynamic supply of Cu, Ni and Zn in a sulphidic freshwater sediment, they were measured, along with iron, manganese and sulphide, by the technique of diffusive gradients in thin-films (DGT). DGT measures the supply of solute from sediment to solution in response to a local solute sink. Release of Mn, Cu, Zn and Ni was observed at the sediment surface and attributed to the supply from reductive dissolution of manganese oxides. The depth profile of simultaneously extractable metals (SEM) for Cu and Ni followed the shape of the Mn profile more closely than the profiles of either acid volatile sulphur (AVS) or Fe, again consistent with supply from Mn oxides. Solubility calculations for a mesocosm of homogenised sediment indicated supersaturation with respect to the sulphides of Fe, Cu, Ni and Zn, yet DGT measurements demonstrated a substantial supply of both trace metals and sulphide from the solid phase to the pore waters. Ratios of metals measured in pore waters by DGT were consistent with their release from iron and manganese oxides, indicating that supply, as much as removal processes, determines the pseudo-steady state concentrations in the pore waters. The observations suggest that trace metals are not immediately bound in an insoluble, inert form when they are in contact with sulphide. This has consequences for modelling metal processes in sediment, as well as for uptake by some biota.

2006-03-15

180

Freshwater autotrophic picoplankton: a review  

Directory of Open Access Journals (Sweden)

Full Text Available Autotrophic picoplankton (APP) are distributed worldwide and are ubiquitous in all types of lakes of varying trophic state. APP are major players in carbon production in all aquatic ecosystems, including extreme environments such as cold ice-covered and/or warm tropical lakes and thermal springs. They often form the base of complex microbial food webs, becoming prey for a multitude of protozoan and micro-invertebrate grazers, that effectively channel APP carbon to higher trophic levels including fish. In this review we examine the existing literature on freshwater autotrophic picoplankton, setting recent findings and current ecological issues within an historic framework, and include a description of the occurrence and distribution of both single-cell and colonial APP (picocyanobacteria) in different types of lakes. In this review we place considerable emphasis on methodology and ecology, including sampling, counting, preservation, molecular techniques, measurement of photosynthesis, and include extensive comment on their important role in microbial food webs. The model outlined by Stockner of an increase of APP abundance and biomass and a decrease of its relative importance with the increase of phosphorus concentration in lakes has been widely accepted, and only recently confirmed in marine and freshwater ecosystems. Nevertheless the relationship which drives the APP presence and importance in lakes of differing trophic status appears with considerable variation so we must conclude that the success of APP in oligotrophic lakes worldwide is not a certainty but highly probable.

Cristiana CALLIERI; John G. STOCKNER

2002-01-01

 
 
 
 
181

Organochlorine pesticide residues in sediments and biota from the coastal area of Dar es Salaam city, Tanzania.  

UK PubMed Central (United Kingdom)

Sediment and biota samples were collected from Msimbazi and Kizinga rivers and from the coastal marine environment of Dar es Salaam during both dry and wet seasons. The samples were analyzed for various organochlorine pesticide residues using GC-ECD and GC-MS. Dieldrin, p,p'-DDT, p,p'-DDE, p,p'-DDD, o,p'-DDT and y-HCH were detected at significantly greater concentrations above the method detection limits. Recoveries of pesticide residues ranged 86.5-120% in sediments and 62-102% in biota. The average concentrations of total DDT in sediments for the two seasons were almost the same. Biota samples showed significant difference in levels of residues depending on mode of feeding and age of analyzed biota. p,p'-DDT to total DDT ratios in all matrices indicated recent use of DDT. The levels of residues in sediments suggest possible adverse effects to humans consuming biota that are directly exposed to the sediments. This effect, which is associated with bio-concentration of residues in the tissues of edible aquatic biota, should not affect wildlife. In spite of concern on the adverse effect to humans posed by pesticide residues in sediments, edible biota from the examined water bodies were found to be safe for human consumption.

Mwevura H; Othman OC; Mhehe GL

2002-01-01

182

Abbreviation of larval development and extension of brood care as key features of the evolution of freshwater Decapoda.  

UK PubMed Central (United Kingdom)

The transition from marine to freshwater habitats is one of the major steps in the evolution of life. In the decapod crustaceans, four groups have colonized fresh water at different geological times since the Triassic, the freshwater shrimps, freshwater crayfish, freshwater crabs and freshwater anomurans. Some families have even colonized terrestrial habitats via the freshwater route or directly via the sea shore. Since none of these taxa has ever reinvaded its environment of origin the Decapoda appear particularly suitable to investigate life-history adaptations to fresh water. Evolutionary comparison of marine, freshwater and terrestrial decapods suggests that the reduction of egg number, abbreviation of larval development, extension of brood care and lecithotrophy of the first posthatching life stages are key adaptations to fresh water. Marine decapods usually have high numbers of small eggs and develop through a prolonged planktonic larval cycle, whereas the production of small numbers of large eggs, direct development and extended brood care until the juvenile stage is the rule in freshwater crayfish, primary freshwater crabs and aeglid anomurans. The amphidromous freshwater shrimp and freshwater crab species and all terrestrial decapods that invaded land via the sea shore have retained ocean-type planktonic development. Abbreviation of larval development and extension of brood care are interpreted as adaptations to the particularly strong variations of hydrodynamic parameters, physico-chemical factors and phytoplankton availability in freshwater habitats. These life-history changes increase fitness of the offspring and are obviously favoured by natural selection, explaining their multiple origins in fresh water. There is no evidence for their early evolution in the marine ancestors of the extant freshwater groups and a preadaptive role for the conquest of fresh water. The costs of the shift from relative r- to K-strategy in freshwater decapods are traded-off against fecundity, future reproduction and growth of females and perhaps against size of species but not against longevity of species. Direct development and extension of brood care is associated with the reduction of dispersal and gene flow among populations, which may explain the high degree of speciation and endemism in directly developing freshwater decapods. Direct development and extended brood care also favour the evolution of social systems, which in freshwater decapods range from simple subsocial organization to eusociality. Hermaphroditism and parthenogenesis, which have evolved in some terrestrial crayfish burrowers and invasive open water crayfish, respectively, may enable populations to adapt to restrictive or new environments by spatio-temporal alteration of their socio-ecological characteristics. Under conditions of rapid habitat loss, environmental pollution and global warming, the reduced dispersal ability of direct developers may turn into a severe disadvantage, posing a higher threat of extinction to freshwater crayfish, primary freshwater crabs, aeglids and landlocked freshwater shrimps as compared to amphidromous freshwater shrimps and secondary freshwater crabs.

Vogt G

2013-02-01

183

Towards a universal sampling protocol for soil biotas in the humid tropics Em direção a um protocolo universal de amostragem de biotas do solo nos trópicos úmidos  

Directory of Open Access Journals (Sweden)

Full Text Available This paper reviews the methods for the inventory of below-ground biotas in the humid tropics, to document the (hypothesized) loss of soil biodiversity associated with deforestation and agricultural intensification at forest margins. The biotas were grouped into eight categories, each of which corresponded to a major functional group considered important or essential to soil function. An accurate inventory of soil organisms can assist in ecosystem management and help sustain agricultural production. The advantages and disadvantages of transect-based and grid-based sampling methods are discussed, illustrated by published protocols ranging from the original "TSBF transect", through versions developed for the alternatives to Slash-and-Burn Project (ASB) to the final schemes (with variants) adopted by the Conservation and Sustainable Management of Below-ground Biodiversity Project (CSM-BGBD). Consideration is given to the place and importance of replication in below-ground biological sampling and it is argued that the new sampling protocols are inclusive, i.e. designed to sample all eight biotic groups in the same field exercise; spatially scaled, i.e. provide biodiversity data at site, locality, landscape and regional levels, and link the data to land use and land cover; and statistically robust, as shown by a partial randomization of plot locations for sampling.Este trabalho faz uma revisão dos métodos de inventariado da biota edáfica nos trópicos úmidos para documentar a (hipotética) perda de biodiversidade do solo associada ao desmatamento e à intensificação agrícola nas margens de florestas. A biota foi agrupada em oito categorias, cada uma correspondente a um grande grupo funcional considerado importante ou essencial para a função do solo. Um inventário cuidadoso dos organismos do solo pode auxiliar a gestão de ecossistemas e a sustentabilidade da produção agrícola. As vantagens e desvantagens de métodos de amostragem baseados em transectos ou em malhas são discutidas e ilustradas por protocolos publicados, desde o original "transeto TSBF", passando por versões desenvolvidas para o projeto "Alternatives to Slash-and-Burn" (ASB), até o esquema final (com suas variantes) adotado pelo projeto "Conservation and Sustainable Management of Below-ground Biodiversity" (CSM-BGBD). Considerou-se a importância de repetição de amostras e argumenta-se que os novos protocolos de amostragem são: inclusivos, ou seja, desenhados para amostrar os oito grupos bióticos ao mesmo tempo no campo; dimensionados espacialmente, pois fornecem dados de biodiversidade nos níveis de lugar, localidade, paisagem e região e associam esses dados ao uso e cobertura do solo; e estatisticamente robustos, como evidenciado por uma aleatorização parcial das localizações dos lotes de amostragem.

David Edward Bignell

2009-01-01

184

Towards a universal sampling protocol for soil biotas in the humid tropics/ Em direção a um protocolo universal de amostragem de biotas do solo nos trópicos úmidos  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Este trabalho faz uma revisão dos métodos de inventariado da biota edáfica nos trópicos úmidos para documentar a (hipotética) perda de biodiversidade do solo associada ao desmatamento e à intensificação agrícola nas margens de florestas. A biota foi agrupada em oito categorias, cada uma correspondente a um grande grupo funcional considerado importante ou essencial para a função do solo. Um inventário cuidadoso dos organismos do solo pode auxiliar a gestão de (more) ecossistemas e a sustentabilidade da produção agrícola. As vantagens e desvantagens de métodos de amostragem baseados em transectos ou em malhas são discutidas e ilustradas por protocolos publicados, desde o original "transeto TSBF", passando por versões desenvolvidas para o projeto "Alternatives to Slash-and-Burn" (ASB), até o esquema final (com suas variantes) adotado pelo projeto "Conservation and Sustainable Management of Below-ground Biodiversity" (CSM-BGBD). Considerou-se a importância de repetição de amostras e argumenta-se que os novos protocolos de amostragem são: inclusivos, ou seja, desenhados para amostrar os oito grupos bióticos ao mesmo tempo no campo; dimensionados espacialmente, pois fornecem dados de biodiversidade nos níveis de lugar, localidade, paisagem e região e associam esses dados ao uso e cobertura do solo; e estatisticamente robustos, como evidenciado por uma aleatorização parcial das localizações dos lotes de amostragem. Abstract in english This paper reviews the methods for the inventory of below-ground biotas in the humid tropics, to document the (hypothesized) loss of soil biodiversity associated with deforestation and agricultural intensification at forest margins. The biotas were grouped into eight categories, each of which corresponded to a major functional group considered important or essential to soil function. An accurate inventory of soil organisms can assist in ecosystem management and help susta (more) in agricultural production. The advantages and disadvantages of transect-based and grid-based sampling methods are discussed, illustrated by published protocols ranging from the original "TSBF transect", through versions developed for the alternatives to Slash-and-Burn Project (ASB) to the final schemes (with variants) adopted by the Conservation and Sustainable Management of Below-ground Biodiversity Project (CSM-BGBD). Consideration is given to the place and importance of replication in below-ground biological sampling and it is argued that the new sampling protocols are inclusive, i.e. designed to sample all eight biotic groups in the same field exercise; spatially scaled, i.e. provide biodiversity data at site, locality, landscape and regional levels, and link the data to land use and land cover; and statistically robust, as shown by a partial randomization of plot locations for sampling.

Bignell, David Edward

2009-08-01

185

Tissue concentrations, bioaccumulation, and biomagnification of synthetic musks in freshwater fish from Taihu Lake, China.  

UK PubMed Central (United Kingdom)

Synthetic musks are ubiquitous pollutants in aquatic environments. As hydrophobic chemicals, they can accumulate in terrestrial and aquatic organisms. Investigations into the bioaccumulation of these chemicals in aquatic ecosystem have, however, been limited, and previous results were inconsistent among species and ecosystem. Studies on this topic have been carried out in European countries, the USA, and Japan, but very few are known of the situation in China. The aim of this study was to investigate contaminant levels of musks in fish from Taihu Lake, the second largest freshwater lake in China, as well as bioaccumulation and biomagnification of the pollutants in the freshwater food chain. Five polycyclic musks and two nitro musks were determined in 24 fish species and nine surface sediment samples from Taihu Lake. HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[?]-2-benzopyran) and AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene) were the predominant contaminants in the fish samples, with concentrations ranging from below the limit of detection (LOD) to 52.9 and from biota-sediment accumulation factors for HHCB and AHTN were noted to increase with trophic levels in fish. Trophic magnification factors were estimated at 1.12 for HHCB and 0.74 for AHTN. A biomagnification for HHCB, and probably biodilution for AHTN, in the freshwater food chain are indicated, when trophic magnification factors were concerned. However, the correlations between logarithmic concentrations of the chemicals and trophic levels were not statistically significant. Further study using long food chains in this lake is still needed.

Zhang X; Xu Q; Man S; Zeng X; Yu Y; Pang Y; Sheng G; Fu J

2013-01-01

186

Tissue concentrations, bioaccumulation, and biomagnification of synthetic musks in freshwater fish from Taihu Lake, China.  

Science.gov (United States)

Synthetic musks are ubiquitous pollutants in aquatic environments. As hydrophobic chemicals, they can accumulate in terrestrial and aquatic organisms. Investigations into the bioaccumulation of these chemicals in aquatic ecosystem have, however, been limited, and previous results were inconsistent among species and ecosystem. Studies on this topic have been carried out in European countries, the USA, and Japan, but very few are known of the situation in China. The aim of this study was to investigate contaminant levels of musks in fish from Taihu Lake, the second largest freshwater lake in China, as well as bioaccumulation and biomagnification of the pollutants in the freshwater food chain. Five polycyclic musks and two nitro musks were determined in 24 fish species and nine surface sediment samples from Taihu Lake. HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[?]-2-benzopyran) and AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene) were the predominant contaminants in the fish samples, with concentrations ranging from below the limit of detection (LOD) to 52.9 and from biota-sediment accumulation factors for HHCB and AHTN were noted to increase with trophic levels in fish. Trophic magnification factors were estimated at 1.12 for HHCB and 0.74 for AHTN. A biomagnification for HHCB, and probably biodilution for AHTN, in the freshwater food chain are indicated, when trophic magnification factors were concerned. However, the correlations between logarithmic concentrations of the chemicals and trophic levels were not statistically significant. Further study using long food chains in this lake is still needed. PMID:22855355

Zhang, Xiaolan; Xu, Qing; Man, Shoukuan; Zeng, Xiangying; Yu, Yingxin; Pang, Yuping; Sheng, Guoying; Fu, Jiamo

2012-08-02

187

KERAGAMAN AKTIVITAS ANTIFUNGI BIOTA LAUT TERHADAP Fusarium oxysporum f.sp. vanillae, PENYEBAB BUSUK BATANG VANILI  

Directory of Open Access Journals (Sweden)

Full Text Available The diversity of marine biota resources is very high, therefore it is necessary to be recovered for our life need. The objective of this research is to know the antifungal ability of marine biota derived from Bali Island against Fusarium oxysporum f. sp. vanillae. Samples were collected at the intertidal zone of seven beaches around Bali. Extraction of antifungal substance of raw material extract was conducted using various organic solvents until the best ability was obtained. The dry material extract was then screened using well diffusion method. The method was also used to determine the inhibition indicators to Fusarium. The methanolic extract of Aglaophenia sp. marine animal was able to suppress the Fusarium effectively, with minimum inhibition concentration (MIC) of 0.05%. The extract inhibited the colony growth, total of conidial forming, total of growing colony, total of mycelial dry weight, total of mycelial protein, however, increased fusaric acid production of the pathogen.

I Ketut Suada

2012-01-01

188

Estimating the mortality to aquatic biota from oil releases under water  

International Nuclear Information System (INIS)

A three-dimensional model has been developed to estimate the mortality of aquatic biota from accidental oil releases near the water surface or in deep water. The model is an extension of model previously developed by Yapa and Zheng. This new model incorporates the concentration distribution of polynuclear aromatic hydrocarbon (PAH) to predict the mortality of aquatic biota. It is believed that PAHs comprise the toxic fraction of crude or refined oil. The composition of petroleum hydrocarbons is important in determining the oil toxicity. Computer models can fill gaps when this complete field data is not available. The computer models can take into account the decomposition of oil properties due to weathering and biological factors. This particular computer model was developed to simulate the duration and exposure of known concentrations to toxic substances. The model estimates the resulting acute mortality of marine species. 63 refs., 20 figs.

2000-01-01

189

Methods for calculating dose conversion coefficients for terrestrial and aquatic biota  

International Nuclear Information System (INIS)

Plants and animals may be exposed to ionizing radiation from radionuclides in the environment. This paper describes the underlying data and assumptions to assess doses to biota due to internal and external exposure for a wide range of masses and shapes living in various habitats. A dosimetric module is implemented which is a user-friendly and flexible possibility to assess dose conversion coefficients for aquatic and terrestrial biota. The dose conversion coefficients have been derived for internal and various external exposure scenarios. The dosimetric model is linked to radionuclide decay and emission database, compatible with the ICRP Publication 38, thus providing a capability to compute dose conversion coefficients for any nuclide from the database and its daughter nuclides. The dosimetric module has been integrated into the ERICA Tool, but it can also be used as a stand-alone version.

2008-01-01

190

Doses to Marine Biota from Radioactive Waste Dumping in the Fjords of Novaya Zemlya  

International Nuclear Information System (INIS)

The current and future radioecological situation has been analysed for the fjords of the Novaya Zemlya archipelago (Abrosimov and Tsivolki Fjords) where the largest radioactive waste (RW) dumping sites are located. The current radiation dose rates to the local marine biota were calculated using the results of the expeditions of 1992-1994, and were found to be very small, (0.5-10) x 10-9 Sv.d-1, with maximum external dose rates up to 8.5 x 10-6 Sv.d-1 within small contaminated spots on the seabed. The future radioecological situation in the Tsivolki Fjord was simulated, using the scenario of an accidental disruption of the RW disposal site in 2050 AD. Dose rates to marine biota in the period of highest releases vary in the range 0.007-0.4 mSv.h-1, with a dominating contribution from alpha-emitting radionuclides. (author)

1998-01-01

191

210Pb and 210Po in Venice Lagoon Biota and their contribution to population dose  

International Nuclear Information System (INIS)

Phosphogypsum is a by-product resulting from the processes applied in phosphoric acid or phosphate fertilizer production. The phosphate ore used in these chemical processes contains the naturally occurring radioactive materials U, and Th, along with their decay products. Large volumes of solid waste products were discharged from a phosphoric acid production plant on the edge of the Venice lagoon (Italy). Water, suspended matter, and biota were monitored in the Venice lagoon, since this aquatic environment can be considered to represent the final area of deposition for the radionuclides transported from inland. The present paper reports data on the activity concentrations of 210Po and 210Pb determined in biota living in the lagoon, and an estimation of the contribution to internal dose to man from the ingestion of food originating in the investigated area. (orig.)

2002-01-01

192

Dechlorane Plus and related compounds in aquatic and terrestrial biota: a review.  

UK PubMed Central (United Kingdom)

Dechlorane Plus, dechlorane 602, dechlorane 603 and dechlorane 604 are flame retardants that have been used for a long time as a substitute for mirex, but they have not been noticed as environmental contaminants until recently (2006). Regardless of their large molecular size and very high lipophilicity (log K(OW)?> 9), Dechlorane Plus and related compounds have been detected in different aquatic and terrestrial species, supporting their bioaccumulation and biomagnification. Moreover, some studies showed different behaviour of the syn-Dechlorane Plus and anti-Dechlorane Plus isomers in the environment and different biomagnification factors in biota. This review describes the different analytical approaches applied to the determination of Dechlorane Plus and related compounds. Moreover, a summary of their levels in aquatic and terrestrial biota, as well as in humans, is presented, showing also current research results on their bioaccumulation and biomagnification potential. Finally, isomer-specific bioaccumulation of Dechlorane Plus is also discussed.

Feo ML; Barón E; Eljarrat E; Barceló D

2012-11-01

193

Feedback mechanisms of soil biota to aboveground biology in terrestrial ecosystems  

Directory of Open Access Journals (Sweden)

Full Text Available Much attention has been paid to the studies of aboveground biological processes in terrestrial ecosystems. Mutual feedbacks between above- and belowground processes have recently become a central interest of ecologists. Soil biota, the most active portion in belowground systems, play crucial roles in processes such as nutrient cycling and energy transformation in terrestrial ecosystems. Soil biota, driven by resource heterogeneity, nutrient availability, and abiotic conditions, could impose direct or indirect and positive or negative feedbacks on aboveground biology by altering rates of nutrient mineralization and the spatial distribution of nutrient availability, rhizospheric hormones and the soil environment. We analyze spatial and temporal variations in soil functional diversity, soil foodweb structure, and the above- and belowground interactions across a wide range of terrestrial ecosystems. These analyses will improve our understanding of belowground ecological processes, and inform the management of ecosystem stability and biodiversity conservation in response to global changes.

Shaojun Wang; Honghua Ruan

2008-01-01

194

Comparative uptake of uranium, thorium, and plutonium by biota inhabiting a contaminated Tennessee floodplain  

Energy Technology Data Exchange (ETDEWEB)

The uptake of /sup 238/U, /sup 232/Th, and /sup 239/Pu from soil by fescue, grasshoppers, and small mammals was compared at the contaminated White Oak Creek floodplain in East Tennessee. Comparisons of actinide uptake were based on analyses of radionuclide ratios (U/Pu and Th/Pu) in soil and biota. U:Pu ratios in small mammal carcasses (shrews, mice, and rats) and bone samples from larger mammals (rabbit, woodchuck, opossum, and raccoon) were significantly greater (P less than or equal to 0.05) than U/Pu ratios in soil (based on 8M HNO/sub 3/ extractable). There was no significant difference between Th/Pu ratios in animals and soil. The order of actinide accumulation by biota from the site relative to contaminated soil was U > Th approx. = Pu.

Garten, C.T. Jr.; Bondietti, E.A.; Walker, R.L.

1981-04-01

195

An adaptation of human food chain models to predicting internal exposure of biota: the Faster model  

Energy Technology Data Exchange (ETDEWEB)

There is an acknowledged lack of available data to derive parameters describing the transfer of many radionuclides from soil to wild species. Furthermore, many approaches to estimating the internal exposure of biota assume equilibrium transfer from soil to biota. However, as environmental impact assessments may need to be conducted for many scenarios (e.g. chronic or acute releases to air and ground waters) assumptions of equilibrium soil to biota transfer many be neither sufficient nor conservative. Much effort has previously been devoted to derive semi-mechanistic models to enable the transfer of radionuclides through human food chains to be predicted dynamically. A logical first step to addressing the data gaps in our ability to predict internal activity concentrations of biota is to consider adapting these models for wild species. Here we describe the development of a semi-mechanistic model to estimate activity concentrations in wild mammals by adaptation of existing human food chain models. Interception, weathering, plant uptake and soil migration parameters are derived from previously published models or collations such as IAEA Technical Report Series No. 364. Allometric relationships dependent on body mass are used to estimate wild animal parameters including, for most radionuclides, biological half-life. Comparison of predictions with observed data allows limited comment on the validity of model predictions. For instance, predicted Cs values are within observed ranges, and an increase in Cs activity concentrations from prey-carnivore as observed by many authors is predicted. Predicted values for {sup 90}Sr, {sup 226}Ra and U also appear reasonable whilst those for the actinide elements are low compared with the limited available data. To date a simple source-grass-herbivore-carnivore food chain has been considered; the potential for further development of the model is discussed. (author)

Avila, R.; Beresford, N.A.; Broed, R.L. [Facilia AB Valsgardevagen, Bromma (Sweden)

2004-07-01

196

Guidance for dispersant decision-making : potential for impacts on aquatic biota  

International Nuclear Information System (INIS)

This presentation discussed issues regarding the uncertainty about the efficacy of dispersant use and the tradeoffs of impact caused by floating versus dispersed oil. Laboratory and tank experimentations have been used to better understand the impacts to water column organisms and the fate and toxicity of oil. The Spill Impact Model Application Package (SIMAP) developed by Applied Science Associates Inc. was run to simulate hypothetical oil spills with and without dispersant use under a range of environmental conditions. SIMAP quantifies fates and concentrations of subsurface oil components, including dissolved and particulate components, along with areas swept by floating oil of various thicknesses. The 3-D physical fates model in SIMAP estimates distribution of whole oil and oil components on the water surface, on shorelines, in the water column, and in sediments. It simulates processes such as spreading; evaporation of volatiles from surface oil; transport on the surface and in the water column; randomized dispersion from small-scale mixing; emulsification; entrainment of oil and droplets into the water; dissolution of soluble components; volatilization of dissolved hydrocarbons from the surface water; adherence of oil droplets to suspended sediments; adsorption of soluble and semi-soluble aromatics to suspended sediments; sedimentation; stranding on shorelines; and degradation. The results revealed the water volume where acute toxic effects would occur and impact birds and other wildlife. In order to put these impact volumes and areas in perspective, typical densities of biota in various geographical regions were used to compare injuries with which to evaluate tradeoffs. As a general conclusion, the tradeoff with respect to wildlife versus water column biota is in favour of dispersant use for oil volumes greater than 2 m3, while remaining protective of all species. Dispersing more than this volume in a single location during a short period of time could impact biota in the surface mixed layer, depending on winds, degree of current shear, weathering state, temperature and sensitivity of the aquatic biota. 35 refs., 1 tab., 15 figs.

2009-01-01

197

Historical records of radioactive contamination in biota at the 200 Areas of the Hanford Site  

Energy Technology Data Exchange (ETDEWEB)

This document summarizes and reports a literature search of 85 environmental monitoring records of wildlife and vegetation (biota) at the 200 East Area and the 200 West Area of the Hanford Site since 1965. These records were published annually and provided the majority of the data in this report. Additional sources of data have included records of specific facilities, such as site characterization documents and preoperational environmental surveys. These documents have been released for public use. Records before 1965 were still being researched and therefore not included in this document. The intent of compiling these data into a single source was to identify past and current concentrations of radionuclides in biota at specific facilities and waste sites within each operable unit that may be used to help guide cleanup activities in the 200 Areas to be completed under the Comprehensive Environmental Response and Liability Act (CERCLA). The 200 East Area and 200 West Area were the locations of the Hanford Site separation and process facilities and waste management units. For the purposes of this document, a sample was of interest if a Geiger-Mueller counter equipped with a pancake probe-indicated beta/gamma emitting radioactivity above 200 counts per minute (cpm), or if laboratory radioanalyses indicated a radionuclide concentration equaled or exceeded 10 picocuries per gram (pCi/g). About 4,500 individual cases of monitoring for radionuclide uptake or transport in biota in the 200 Areas environs were included in the documents reviewed. About 1,900 (i.e., 42%) of these biota had radionuclide concentrations in excess of 10 pCi/g. These radionuclide transport or uptake cases were distributed among 45 species of wildlife (primarily small mammals and feces) and 30 species of vegetation. The wildlife species most commonly associated with radioactive contamination were the house mouse and the deer mouse and of vegetation species, the Russian thistle.

Johnson, A.R.; Markes, B.M.; Schmidt, J.W.; Shah, A.N.; Weiss, S.G.; Wilson, K.J.

1994-06-01

198

Guidance for dispersant decision-making : potential for impacts on aquatic biota  

Energy Technology Data Exchange (ETDEWEB)

This presentation discussed issues regarding the uncertainty about the efficacy of dispersant use and the tradeoffs of impact caused by floating versus dispersed oil. Laboratory and tank experimentations have been used to better understand the impacts to water column organisms and the fate and toxicity of oil. The Spill Impact Model Application Package (SIMAP) developed by Applied Science Associates Inc. was run to simulate hypothetical oil spills with and without dispersant use under a range of environmental conditions. SIMAP quantifies fates and concentrations of subsurface oil components, including dissolved and particulate components, along with areas swept by floating oil of various thicknesses. The 3-D physical fates model in SIMAP estimates distribution of whole oil and oil components on the water surface, on shorelines, in the water column, and in sediments. It simulates processes such as spreading; evaporation of volatiles from surface oil; transport on the surface and in the water column; randomized dispersion from small-scale mixing; emulsification; entrainment of oil and droplets into the water; dissolution of soluble components; volatilization of dissolved hydrocarbons from the surface water; adherence of oil droplets to suspended sediments; adsorption of soluble and semi-soluble aromatics to suspended sediments; sedimentation; stranding on shorelines; and degradation. The results revealed the water volume where acute toxic effects would occur and impact birds and other wildlife. In order to put these impact volumes and areas in perspective, typical densities of biota in various geographical regions were used to compare injuries with which to evaluate tradeoffs. As a general conclusion, the tradeoff with respect to wildlife versus water column biota is in favour of dispersant use for oil volumes greater than 2 m{sup 3}, while remaining protective of all species. Dispersing more than this volume in a single location during a short period of time could impact biota in the surface mixed layer, depending on winds, degree of current shear, weathering state, temperature and sensitivity of the aquatic biota. 35 refs., 1 tab., 15 figs.

French McCay, D.; Graham, E. [Applied Science Associates Inc., South Kingstown, RI (United States)

2009-07-01

199

Biota of a Pennsylvanian muddy coast: habitat within the Mazonian delta complex, northeast Illinois  

Energy Technology Data Exchange (ETDEWEB)

The Mazon Creek biota (Westphalian D) is composed of plants and animals from terrestrial fresh water and marginal marine habitats. Fossil animals, including jellyfish, worms, crustaceans, holothurians, insects, chordates, and problematica occur in sideritic concretions on spoilpiles of more than 100 abandoned coal mines in a five county region (Mazon Creek area) of northeast Illinois. These fossils record rapid burial and early diagenesis in a muddy, delta-influenced coastal setting submerged during marine transgression.

Baird, G.C.

1985-03-01

200

Historical records of radioactive contamination in biota at the 200 Areas of the Hanford Site  

International Nuclear Information System (INIS)

This document summarizes and reports a literature search of 85 environmental monitoring records of wildlife and vegetation (biota) at the 200 East Area and the 200 West Area of the Hanford Site since 1965. These records were published annually and provided the majority of the data in this report. Additional sources of data have included records of specific facilities, such as site characterization documents and preoperational environmental surveys. These documents have been released for public use. Records before 1965 were still being researched and therefore not included in this document. The intent of compiling these data into a single source was to identify past and current concentrations of radionuclides in biota at specific facilities and waste sites within each operable unit that may be used to help guide cleanup activities in the 200 Areas to be completed under the Comprehensive Environmental Response and Liability Act (CERCLA). The 200 East Area and 200 West Area were the locations of the Hanford Site separation and process facilities and waste management units. For the purposes of this document, a sample was of interest if a Geiger-Mueller counter equipped with a pancake probe-indicated beta/gamma emitting radioactivity above 200 counts per minute (cpm), or if laboratory radioanalyses indicated a radionuclide concentration equaled or exceeded 10 picocuries per gram (pCi/g). About 4,500 individual cases of monitoring for radionuclide uptake or transport in biota in the 200 Areas environs were included in the documents reviewed. About 1,900 (i.e., 42%) of these biota had radionuclide concentrations in excess of 10 pCi/g. These radionuclide transport or uptake cases were distributed among 45 species of wildlife (primarily small mammals and feces) and 30 species of vegetation. The wildlife species most commonly associated with radioactive contamination were the house mouse and the deer mouse and of vegetation species, the Russian thistle

 
 
 
 
201

Fuzzy logic modeling of bioaccumulation pattern of metals in coastal biota of Ondo State, Nigeria.  

UK PubMed Central (United Kingdom)

The accumulation patterns of ten metals in tissues of plant, Eichornia crassipes, and fishes, Hydrocynus forskahlii and Oreochromis mossambicus, were modeled with simple fuzzy classification (SFC) to assess toxic effects of anthropogenic activities on the coastal biota. The plant sample was separated into root, stem, and leaves and the fishes into bones, internal tissues, and muscles. They were analyzed for As, Cd, Cr, Cu, Ni, Pb, V, Fe, Mn, and Zn after wet oxidation of their dried samples. The results were converted into membership functions of five accumulation classes and aggregated with SFC. The classification results showed that there was no metal accumulation in the plant parts while the fishes were classified into low accumulation category. The internal tissues of the fishes had higher metal accumulation than the other parts. Generally, Fe and Mn had highest concentrations in the biota but are natural to the area and may not constitute significant risk. Cr had the highest transfer and accumulation from the coastal water into the aquatic lives and may be indicative of risk prone system being a toxic metal. Metal contaminations in the zone had not significantly accumulated in the biota making them less prone to risk associated with metal accumulation.

Agunbiade FO; Olu-Owolabi BI; Adebowale KO

2012-01-01

202

Non-human biota dose assessment. Sensitivity analysis and knowledge quality assessment  

International Nuclear Information System (INIS)

This report provides a summary of a programme of work, commissioned within the BIOPROTA collaborative forum, to assess the quantitative and qualitative elements of uncertainty associated with biota dose assessment of potential impacts of long-term releases from geological disposal facilities (GDF). Quantitative and qualitative aspects of uncertainty were determined through sensitivity and knowledge quality assessments, respectively. Both assessments focused on default assessment parameters within the ERICA assessment approach. The sensitivity analysis was conducted within the EIKOS sensitivity analysis software tool and was run in both generic and test case modes. The knowledge quality assessment involved development of a questionnaire around the ERICA assessment approach, which was distributed to a range of experts in the fields of non-human biota dose assessment and radioactive waste disposal assessments. Combined, these assessments enabled critical model features and parameters that are both sensitive (i.e. have a large influence on model output) and of low knowledge quality to be identified for each of the three test cases. The output of this project is intended to provide information on those parameters that may need to be considered in more detail for prospective site-specific biota dose assessments for GDFs. Such information should help users to enhance the quality of their assessments and build greater confidence in the results. (orig.)

2010-01-01

203

Cretaceous biota of the Triângulo Mineiro region (Brazil): A review of recent finds  

Directory of Open Access Journals (Sweden)

Full Text Available The Bauru Group (Adamantina, Uberaba, and Marília Formations) crop out in the Triângulo Mineiro region, Minas Gerais State, Brazil, and yield a rich continental biota. Invertebrate and vertebrate taxa from underlying and overlying strata, as well as biostratigraphical correlations with other fossil sites in Argentina, suggest an Upper Cretaceous age for this biota. The diversity of the fossil assemblage recorded in these formations is summarized here and includes: frogs, lizards, crocodiles, titanosaurs, abelisaurid and carcharodontosaurid dinosaurs. This fossil assemblage provides important clues to understand faunas from other southern landmasses, particularly those from the Cretaceous of the African continent.Los afloramientos del Grupo Bauru (formaciones Adamantina, Uberaba y Marília) en la región del Triângulo Mineiro, Provincia de Minas Gerais, Brasil, posee un rico contenido de biota continental. Los taxa de invertebrados y vertebrados de estos estratos, así como las correlaciones biostratigráficas con otros yacimientos fósiles de Argentina, sugieren una edad del Cretácico Tardío. La diversidad de la asociación fósil registrada en las formaciones del Triângulo Mineiro se resume en el presente trabajo e incluye: sapos, lagartos, tortugas, cocodrilianos, titanosaurideos, dinosaurios abelisaurideos y carcharodontosaurideos. Esta asociación es importante para la comprensión de las faunas del sur de América y también de las del Cretácico de África.

Candeiro, C. R. A.

2007-01-01

204

On the Origin of Pantepui montane biotas: A Perspective Based on the Phylogeny of Aulacorhynchus toucanets  

Science.gov (United States)

To understand the origin of Pantepui montane biotas, we studied the biogeography of toucanets in the genus Aulacorhynchus. These birds are ideal for analyzing historical relationships among Neotropical montane regions, given their geographic distribution from Mexico south to Bolivia, including northern Venezuela (Cordillera de la Costa), and the Pantepui. Analyses were based on molecular phylogenies using mitochondrial and nuclear DNA sequences. Topology tests were applied to compare alternative hypotheses that may explain the current distribution of Aulacorhynchus toucanets, in the context of previous hypotheses of the origin of Pantepui montane biotas. Biogeographic reconstructions in RASP and Lagrange were used to estimate the ancestral area of the genus, and an analysis in BEAST was used to estimate a time framework for its diversification. A sister relationship between the Pantepui and Andes+Cordillera de la Costa was significantly more likely than topologies indicating other hypothesis for the origin of Pantepui populations. The Andes was inferred as the ancestral area for Aulacorhynchus, and the group has diversified since the late Miocene. The biogeographic patterns found herein, in which the Andes are the source for biotas of other regions, are consistent with those found for flowerpiercers and tanagers, and do not support the hypothesis of the geologically old Pantepui as a source of Neotropical montain diversity. Based on the high potential for cryptic speciation and isolation of Pantepui populations, we consider that phylogenetic studies of additional taxa are important from a conservation perspective.

Bonaccorso, Elisa; Guayasamin, Juan M.

2013-01-01

205

Concentrations and characteristics of organochlorine pesticides in aquatic biota from Qiantang River in China  

International Nuclear Information System (INIS)

[en] The Qiantang River is a typical river flowing through an agricultural area in China. It was studied in 2006 for its aquatic biota quality by determining 13 organochlorine pesticides (OCPs) in the edible parts of crabs, clams, shrimp, fish, aquatic plants, as well as water and sediments collected from seven sites along its upper reaches all the way downstream. The levels of all insecticides were in the range of 17 ± 13 (water plants), 35 ± 36 (shrimp), 32 ± 14 (crabs), 39 ± 21 (clams), 47±35 (fish) ng/g wet weight (ww) and in the range of 2936 ± 2356 (water plants), 5827 ± 6013 (shrimp), 2102 ± 966 (crabs), 1859 ± 1018 (clams), 3624 ± 11331 (fish) ng/g lipid. DDT and its metabolites were the predominant contaminants in most biota. A linear relationship was observed between the log bio-concentration factor (BCF) and log octanol-water partition coefficients (Kow) for fish, clams and shrimp. Composition analyses in various environmental media indicated a recent usage of lindane and dicofol into the river. - OCP residues still exist in aquatic biota from Qiantang River after the ban of OCPs twenty years ago

2008-01-01

206

On the Origin of Pantepui montane biotas: A Perspective Based on the Phylogeny of Aulacorhynchus toucanets.  

UK PubMed Central (United Kingdom)

To understand the origin of Pantepui montane biotas, we studied the biogeography of toucanets in the genus Aulacorhynchus. These birds are ideal for analyzing historical relationships among Neotropical montane regions, given their geographic distribution from Mexico south to Bolivia, including northern Venezuela (Cordillera de la Costa), and the Pantepui. Analyses were based on molecular phylogenies using mitochondrial and nuclear DNA sequences. Topology tests were applied to compare alternative hypotheses that may explain the current distribution of Aulacorhynchus toucanets, in the context of previous hypotheses of the origin of Pantepui montane biotas. Biogeographic reconstructions in RASP and Lagrange were used to estimate the ancestral area of the genus, and an analysis in BEAST was used to estimate a time framework for its diversification. A sister relationship between the Pantepui and Andes+Cordillera de la Costa was significantly more likely than topologies indicating other hypothesis for the origin of Pantepui populations. The Andes was inferred as the ancestral area for Aulacorhynchus, and the group has diversified since the late Miocene. The biogeographic patterns found herein, in which the Andes are the source for biotas of other regions, are consistent with those found for flowerpiercers and tanagers, and do not support the hypothesis of the geologically old Pantepui as a source of Neotropical montain diversity. Based on the high potential for cryptic speciation and isolation of Pantepui populations, we consider that phylogenetic studies of additional taxa are important from a conservation perspective.

Bonaccorso E; Guayasamin JM

2013-01-01

207

In vivo cytogenetic and oxidative stress-inducing effects of cypermethrin in freshwater fish, Channa punctata Bloch.  

UK PubMed Central (United Kingdom)

Synthetic pyrethroids are considered to be safe over other insecticides. Many of the newest pyrethroids lack ecotoxicity data. However, animal data indicate that their use may pose risk to environmental biota. The cytogenetic effects of cypermethrin, an ?-class type II pyrethroid were evaluated using robust genotoxicity assay of chromosomal aberration (CA) and micronucleus (MN) tests in highly mitotic kidney cells and in erythrocytes of a freshwater fish, Channa punctata Bloch. In order to understand biochemical mechanism of genotoxic effects, oxidative stress parameters were also studied in fish erythrocytes. Fish exposed to cypermethrin (0.4, 0.8 and 1.2 ?g/l for 48 and 72 h) showed increased frequencies of CA and MN in a concentration-dependent manner. Fish exposed to positive genotoxin, ethyl methane sulfonate (EMS) also showed significant increase in frequencies of CA and MN. The genotoxic effects were invariably accompanied and correlated with increased oxidative stress and disturbance of antioxidant enzymes.

Ansari RA; Rahman S; Kaur M; Anjum S; Raisuddin S

2011-01-01

208

Radionuclide and heavy metal concentrations in water, sediments and biota in the vicinity of Cluff mining operations  

International Nuclear Information System (INIS)

Data is presented on the concentrations of U, Ra-226, Pb-210, Th-230, Th, As, Cu, Pb, Mo, Ni and Zn in water, sediments, aquatic macrophytes and fish near a high grade uranium mining facility. Baseline data acquired in 1975 and 1978-79 is compared to post-development environmental monitoring data from 1980 to 1985. Distribution coefficients (KD) for sediment, and transfer coefficients (T.C.) for biota and derived from the water, sediment and biota concentrations.

1986-01-01

209

Toxicity of metallic oxides nanoparticle suspensions to a freshwater sludge worm Tubifex tubifex Muller.  

UK PubMed Central (United Kingdom)

Toxic effects of selected metallic oxides nanoparticles were studied using the short-term static bioassays. Nanoparticles were more toxic than comparable bulk metallic oxides. Freshwater sludge worm Tubifex tubifex can be used as suitable test model for nanoecotoxicological studies in future studies.

Verma S; Das S; Khangarot BS

2011-02-01

210

Concentrations and accumulation features of organochlorine pesticides in the Baiyangdian Lake freshwater food web of North China.  

UK PubMed Central (United Kingdom)

Organochlorine pesticides (OCPs), such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), are ubiquitous anthropogenic environmental contaminants. They are persistent, broad-spectrum toxicants that accumulate in the food web with potential risks to the ecosystem and human health. HCHs were the predominant contaminants in Baiyangdian Lake, North China. Concentrations of HCHs and DDTs ranged from 58 to 563 ng/g lipid weight (lw) and 21 to 401 ng/g lw, respectively, for aquatic biota samples. The highest levels of HCHs and DDTs were observed in muscles of yellow catfish. The mean concentrations of OCPs were 4.6 ng/L for water, 95 ng/g dry weight (dw) for aquatic plants, and 14 ng/g dw for sediments. Among the isomers and metabolites, alpha-HCH and p,p'-1,1-di(p-chlorophenyl)-2,2-dichloroethylene (p,p'-DDE) were the predominant congeners in biota samples. Correlations between log lipid-normalized concentrations of HCHs and DDTs and trophic levels (TLs) based on analysis of stable isotopes of nitrogen confirmed that persistent organic pollutants were magnified in the Baiyangdian Lake food web. Significant positive relationships were found for alpha-HCH and p,p'-DDT and their trophic magnification factors, which were 1.6 and 1.7, respectively. These results provide evidence of biomagnification of persistent organic pollutants (POPs) in freshwater food webs.

Hu G; Dai J; Mai B; Luo X; Cao H; Wang J; Li F; Xu M

2010-04-01

211

Capture efficiency and size selectivity of sampling gears targeting red-swamp crayfish in several freshwater habitats Efficacité de capture et sélectivité des tailles d’écrevisses rouges de Louisiane échantillonnées par différents engins de pêche dans plusieurs habitats dulçaquicoles  

Directory of Open Access Journals (Sweden)

Full Text Available The ecological importance of the red-swamp crayfish (Procambarus clarkii) in the functioning of freshwater aquatic ecosystems is becoming more evident. It is important to know the limitations of sampling methods targeting this species, because accurate determination of population characteristics is required for predicting the ecological success of P. clarkii and its potential impacts on invaded ecosystems. In the current study, we addressed the question of trap efficiency by comparing population structure provided by eight trap devices (varying in number and position of entrances, mesh size, trap size and construction materials) in three habitats (a pond, a reed bed and a grassland) in a French marsh in spring 2010. Based on a large collection of P. clarkii (n = 2091, 272 and 213 respectively in the pond, reed bed and grassland habitats), we found that semi-cylindrical traps made from 5.5 mm mesh galvanized steel wire (SCG) were the most efficient in terms of catch probability (96.7–100% compared to 15.7–82.8% depending on trap types and habitats) and catch-per-unit effort (CPUE: 15.3, 6.0 and 5.1 crayfish·trap-1·24 h-1 compared to 0.2–4.4, 2.9 and 1.7 crayfish·trap-1·24 h-1 by the other types of fishing gear in the pond, reed bed and grassland respectively). The SCG trap was also the most effective for sampling all size classes, especially small individuals (carapace length hbox{$leqslant 30$} ? 30 mm). Sex ratio was balanced in all cases. SCG could be considered as appropriate trapping gear to likely give more realistic information about P. clarkii population characteristics than many other trap types. Further investigation is needed to assess the catching effort required for ultimately proposing a standardised sampling method in a large range of habitats. L’importance écologique de l’écrevisse rouge de Louisiane (Procambarus clarkii) dans le fonctionnement des écosystèmes aquatiques dulçaquicoles est de plus en plus reconnue. Puisque la détermination précise des caractéristiques populationnelles est essentielle pour prédire le succès écologique de P. clarkii et ses impacts potentiels sur les écosystèmes envahis, il est important de connaître les limites des méthodes d’échantillonnage. Dans la présente étude, nous traitons de la question de l’efficacité de piégeage en comparant les caractéristiques populationnelles fournies par huit types de pièges (variant selon le nombre et la position des entrées, la taille de maille, la taille du piège et les matériaux de construction) dans trois habitats (un plan d’eau, une roselière et une prairie inondée) d’un marais en France, et cela au printemps 2010. Sur la base d’un large échantillonnage d’écrevisses (n = 2091, 272 et 213 individus capturés respectivement dans le plan d’eau, la roselière et la prairie inondée), nous avons mis en évidence que les pièges semi-cylindriques en acier galvanisé et de maille de 5,5 mm (SCG) étaient les plus efficaces en termes de probabilité de capture (96,7–100 % comparés aux 15,7–82,8 % obtenus dans les autres pièges et dans les trois habitats) et de capture par unité d’effort (CPUE : 15,3; 6,0 et 5,1 écrevisses·piège-1·24 h-1 contre 0,2–4,4; 2,9 et 1,7 écrevisses·piège-1·24 h-1 trouvées dans les autres pièges respectivement dans le plan d’eau, la roselière et la prairie inondée). Les pièges SCG étaient également les plus efficaces pour échantillonner toutes les classes de taille, et particulièrement les petites écrevisses (longueur de carapace hbox{$leqslant 30$} ? 30 mm). Le sexe ratio était équilibré dans tous les cas. Les pièges SCG pourraient être considérés comme un engin de pêche approprié pour fournir des informations probablement plus réalistes sur les caractéristiques de populations de P. clarkii que de nombreux autres types de piège. Des études supplémentaires sont nécessaires afin d’évaluer l’effort d’échantillonnage requis pour finalement proposer une méthode d’échantillonnage sta

Paillisson J.-M.; Soudieux A.; Damien J.-P.

2011-01-01

212

Inland oil spills: Options for minimizing environmental impacts of freshwater spill response  

Energy Technology Data Exchange (ETDEWEB)

Selecting appropriate protection, response, and cleanup techniques, both before and following an oil spill, affects the ultimate environmental impact and cost resulting from a spill. The American Petroleum Institute (API) and the National Oceanic and Atmospheric Administration (NOAA) jointly developed this guide as a tool for contingency planners and field responders to identify response techniques that have minimal ecological impacts and also minimize the impact of the oil. The guide provides information on 29 response methods and classifies their relative environmental impact for combinations of four oil types and twelve freshwater environments and habitats. Spill topics of special concern in freshwater settings are also discussed, including public health, conditions under which oil might sink in freshwater, oil behavior in ice conditions, permafrost, and use of firefighting foams.

1994-09-01

213

Global priorities for conservation of threatened species, carbon storage, and freshwater services : scope for synergy?  

DEFF Research Database (Denmark)

The potential of global biodiversity conservation efforts to also deliver critical benefits, such as carbon storage and freshwater services, is still unclear. Using spatially explicit data on 3,500 range-restricted threatened species, carbon storage, and freshwater provision to people, we conducted tradeoff analyses, explicitly addressing both biodiversity and ecosystem services in selection of priority areas, to explore the potential for aligning these objectives. These analyses revealed a promising scope for aligning objectives, in particular for biodiversity and freshwater, which is not evident from previous studies that merely analyzed overlap of biodiversity and ecosystem services derived for each objective independently. However, this alignment is not complete. By revealing important synergies and tradeoffs among services, these analyzes suggest particular regions and service combinations for which spatial planning and appropriate conservation mechanisms (e.g., payments for ecosystem services) can be used to realize synergies and mitigate tradeoffs.

Larsen, Frank Wugt; Londoño-Murcia, Maria C.

2011-01-01

214

The molecular phylogeny of freshwater Dothideomycetes  

Directory of Open Access Journals (Sweden)

Full Text Available The freshwater Dothideomycetes species are an ecological rather than taxonomic group and comprise approximately 178 meiosporic and mitosporic species. Due to convergent or parallel morphological adaptations to aquatic habitats, it is difficult to determine phylogenetic relationships among freshwater taxa and among freshwater, marine and terrestrial taxa based solely on morphology. We conducted molecular sequence-based phylogenetic analyses using nuclear ribosomal sequences (SSU and/or LSU) for 84 isolates of described and undescribed freshwater Dothideomycetes and 85 additional taxa representative of the major orders and families of Dothideomycetes. Results indicated that this ecological group is not monophyletic and all the freshwater taxa, except three aeroaquatic Tubeufiaceae, occur in Pleosporomycetidae as opposed to Dothideomycetidae. Four clades comprised of only freshwater taxa were recovered. The largest of these is the Jahnulales clade consisting of 13 species, two of which are the anamorphs Brachiosphaera tropicalis and Xylomyces chlamydosporus. The second most speciose clade is the Lindgomycetaceae clade consisting of nine taxa including the anamorph Taeniolella typhoides. The Lindgomycetaceae clade consists of taxa formerly described in Massarina, Lophiostoma, and Massariosphaeria e.g., Massarina ingoldiana, Lophiostoma breviappendiculatum, and Massariosphaeria typhicola and several newly described and undescribed taxa. The aquatic family Amniculicolaceae, including three species of Amniculicola, Semimassariosphaeria typhicola and the anamorph, Anguillospora longissima, was well supported. A fourth clade of freshwater species consisting of Tingoldiago graminicola, Lentithecium aquaticum, L. arundinaceum and undescribed taxon A-369-2b was not well supported with maximum likelihood bootstrap and Bayesian posterior probability. Eight freshwater taxa occurred along with terrestrial species in the Lophiostoma clades 1 and 2. Two taxa lacking statistical support for their placement with any taxa included in this study are considered singletons within Pleosporomycetidae. These singletons, Ocala scalariformis, and Lepidopterella palustris, are morphologically distinct from other taxa in Pleosporomycetidae. This study suggests that freshwater Dothideomycetes are related to terrestrial taxa and have adapted to freshwater habitats numerous times. In some cases (Jahnulales and Lindgomycetaceae), species radiation appears to have occurred. Additional collections and molecular study are required to further clarify the phylogeny of this interesting ecological group.

C.A. Shearer; H.A. Raja; A.N. Miller; P. Nelson; K. Tanaka; K. Hirayama; L. Marvanova; K.D. Hyde; Y. Zhang

2009-01-01

215

Ultimobranchial gland of freshwater catfish, Heteropneustes fossilis, in response to calcitonin administration  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The absence o!!f a hypocalcemic effect of calcitonin (CT) in fishes has been suggested due to exceedingly high plasma levels of CT; the fish may be saturated with respect of circulating CT and therefore unable to respond to exogenously administered CT. Earlier it has been suggested that a hypocalcemic action of injected CT may be obscured by changes in the release of endogenous CT and other calcium regulating hormones. In this study we have used artificial freshwater, cal (more) cium-deficient freshwater and calcium-rich freshwater and injected the fish with CT. The aim behind selecting these media were (i) in calcium-deficient medium there would be reduced circulating levels of CT, (ii) in calcium-rich medium there would be diminished secretion of prolactin (this hormone is hypercalcemic in fish), and (iii) by keeping the fish in calcium-rich medium we can test the antihypercalcemic action of CT. Moreover, the present study would reveal the changes in the ultimobranchial gland (UBG) after keeping the fish in all the above three media and/or injecting the fish with CT. Freshwater catfish, Heteropneustes fossilis, were administered intraperitoneally daily with vehicle or 0.5 U/100g body wt of salmon calcitonin (CT) and kept in artificial freshwater, calcium-rich freshwater and calcium-deficient freshwater for 10 days. Blood samples were collected on 1, 3, 5, and 10 days following the treatment and analyzed for serum calcium levels. The ultimobranchial gland (UBG) was also fixed for histological studies on these intervals. In artificial freshwater there was no change in the serum calcium levels of calcitonin-injected fish. The ultimobranchial gland of calcitonin-injected fish exhibited a progressive decrease in the nuclear volume from day 5 onwards. On day 10 vacuolization in the gland was also noticed. In vehicle-injected fish (control) kept in calcium-rich freshwater hypercalcemia has been noticed which persists till the end of the experiment. In calcitonin-treated fish maintained in calcium-rich freshwater there is no change in serum calcium level as compared to vehicle-injected fish. In vehicle-injected fish the UBG depicts decreased staining response and increased nuclear volume at day 5. On day 10 the nuclear volume is further increased and few degenerating cells have been noticed. Calcitonin fails to induce any histological change in the UBG as compared to control. In vehicle-injected fish kept in calcium-deficient freshwater the serum calcium levels decrease from day 1 to day 3. The levels exhibit hypercalcemia on day 10. CT treatment to the fish kept in calcium-deficient freshwater evokes a decrease in the calcium levels on day 1 and day 3. A significant hypercalcemia has been noticed on day 5 and day 10. In vehicle-injected fish kept in calcium-deficient freshwater the UBG reveals a decreased staining response on day 10. In CT-injected fish maintained in calcium-deficient freshwater the UBG depicts an increased nuclear volume and few exhausted cells on day 10. It can be concluded that CT can provoke hypocalcemia only when the fish is kept in medium which reduces the circulating levels of this hormone. The UBG of the fish kept in different calcemic media responded in a manner to indicate that it produces hypocalcemic factor - CT.

Srivastav, Ajai K.; Singh, Sarita; Mishra, Diwakar; Srivastav, S.K.

2009-12-01

216

Ultimobranchial gland of freshwater catfish, Heteropneustes fossilis, in response to calcitonin administration  

Directory of Open Access Journals (Sweden)

Full Text Available The absence o!!f a hypocalcemic effect of calcitonin (CT) in fishes has been suggested due to exceedingly high plasma levels of CT; the fish may be saturated with respect of circulating CT and therefore unable to respond to exogenously administered CT. Earlier it has been suggested that a hypocalcemic action of injected CT may be obscured by changes in the release of endogenous CT and other calcium regulating hormones. In this study we have used artificial freshwater, calcium-deficient freshwater and calcium-rich freshwater and injected the fish with CT. The aim behind selecting these media were (i) in calcium-deficient medium there would be reduced circulating levels of CT, (ii) in calcium-rich medium there would be diminished secretion of prolactin (this hormone is hypercalcemic in fish), and (iii) by keeping the fish in calcium-rich medium we can test the antihypercalcemic action of CT. Moreover, the present study would reveal the changes in the ultimobranchial gland (UBG) after keeping the fish in all the above three media and/or injecting the fish with CT. Freshwater catfish, Heteropneustes fossilis, were administered intraperitoneally daily with vehicle or 0.5 U/100g body wt of salmon calcitonin (CT) and kept in artificial freshwater, calcium-rich freshwater and calcium-deficient freshwater for 10 days. Blood samples were collected on 1, 3, 5, and 10 days following the treatment and analyzed for serum calcium levels. The ultimobranchial gland (UBG) was also fixed for histological studies on these intervals. In artificial freshwater there was no change in the serum calcium levels of calcitonin-injected fish. The ultimobranchial gland of calcitonin-injected fish exhibited a progressive decrease in the nuclear volume from day 5 onwards. On day 10 vacuolization in the gland was also noticed. In vehicle-injected fish (control) kept in calcium-rich freshwater hypercalcemia has been noticed which persists till the end of the experiment. In calcitonin-treated fish maintained in calcium-rich freshwater there is no change in serum calcium level as compared to vehicle-injected fish. In vehicle-injected fish the UBG depicts decreased staining response and increased nuclear volume at day 5. On day 10 the nuclear volume is further increased and few degenerating cells have been noticed. Calcitonin fails to induce any histological change in the UBG as compared to control. In vehicle-injected fish kept in calcium-deficient freshwater the serum calcium levels decrease from day 1 to day 3. The levels exhibit hypercalcemia on day 10. CT treatment to the fish kept in calcium-deficient freshwater evokes a decrease in the calcium levels on day 1 and day 3. A significant hypercalcemia has been noticed on day 5 and day 10. In vehicle-injected fish kept in calcium-deficient freshwater the UBG reveals a decreased staining response on day 10. In CT-injected fish maintained in calcium-deficient freshwater the UBG depicts an increased nuclear volume and few exhausted cells on day 10. It can be concluded that CT can provoke hypocalcemia only when the fish is kept in medium which reduces the circulating levels of this hormone. The UBG of the fish kept in different calcemic media responded in a manner to indicate that it produces hypocalcemic factor - CT.

Ajai K. Srivastav; Sarita Singh; Diwakar Mishra; S.K. Srivastav

2009-01-01

217

Commissioned Review. Carbon: freshwater plants  

Science.gov (United States)

?13C values for freshwater aquatic plant matter varies from ?11 to ?50‰ and is not a clear indicator of photosynthetic pathway as in terrestrial plants. Several factors affect ?13C of aquatic plant matter. These include: (1) The ?13C signature of the source carbon has been observed to range from +1‰ for HCO3? derived from limestone to ?30‰ for CO2 derived from respiration. (2) Some plants assimilate HCO3?, which is –7 to –11‰ less negative than CO2. (3) C3, C4, and CAM photosynthetic pathways are present in aquatic plants. (4) Diffusional resistances are orders of magnitude greater in the aquatic environment than in the aerial environment. The greater viscosity of water acts to reduce mixing of the carbon pool in the boundary layer with that of the bulk solution. In effect, many aquatic plants draw from a finite carbon pool, and as in terrestrial plants growing in a closed system, biochemical discrimination is reduced. In standing water, this factor results in most aquatic plants having a ?13C value similar to the source carbon. Using Farquhar's equation and other physiological data, it is possible to use ?13C values to evaluate various parameters affecting photosynthesis, such as limitations imposed by CO2 diffusion and carbon source.

Keeley, J. E.; Sandquist, D. R.

1992-01-01

218

Methane release by freshwater pockmarks  

Science.gov (United States)

In the eastern part of Lake Constance (Germany) near the Rhine River hundreds of pockmarks, morphological depressions at the lake floor, were observed. The diameter of these pockmarks was up to 16 m and at a high number of them permanent release of methane bubbles was detected. The isotopic analysis of the escaping gas indicated methane of biogenic origin.. At the shallow pockmarks (10 m), migration of gas bubbles through the sediment caused increased methane concentrations in the pore waters close to the sediments as compared to sites unaffected by bubble migration outside the pockmarks. Thus, the diffusive methane flux and oxidation rates were much higher inside the pockmark than outside. Nevertheless, methane ebullition into the water column is by far the dominating pathway of methane release (estimated 10 L h-1). At the deep pockmark (80 m) - even though bubble release was observed -, the sediment inside the pockmark had the same methane concentrations and geochemistry compared with a reference site outside the pockmark. In profundal freshwater sediments a strong recent methanogenesis leads to high methane concentrations, often above saturation. So, additional emerging methane (bubbles) from deeper layers escapes from the sediment essentially unaffected by diffsuion into the sediment or by methane oxidation. Thus, the background concentration of methane in the sediment, determines if methane passes through the sedimentary filter or is directly released into the water column and possibly the atmosphere.

Bussmann, Ingeborg; Schlömer, Stefan; Schlüter, Michael; Wessels, Martin

2010-05-01

219

Radiation dose and countermeasure model for a decision support system on freshwater ecosystems contaminated with radionuclides  

International Nuclear Information System (INIS)

With the participation of several European institutions The MOIRA project (A MOdel based computerised system for management support to Identify optimal remedial strategies for Restoring radionuclide contaminated Aquatic ecosystems, European Commission contract FI4P-CT96-0036) has developed a computerised Decision Support System that will allow decision makers to choose optimal intervention strategies for freshwater ecosystems with different radioactive contamination scenarios. An important factor for the decision analysis is the radiation dose resulting to humans and biota from the contamination. Not less important is to quantify the impact that intervention strategies may have on the potential resulting dose. With that aim, the system is incorporating a dose and countermeasure model, very flexible, that is able to estimate dose to the critical individuals and collective dose to the affected population, as well as maximum dose to fish species, representative of the threats to biota from radioactive contamination of water bodies. The model main characteristics are: Applicable to different water bodies (in principle lakes and rivers) contaminated with Cs-137 and/or Sr-90. The model is driven by the time series of radionuclide concentrations in the water, in the bottom sediments and fish (predator and prey species), which are the output from other environmental models of the MOIRA system. Main sub-models: individual and collective external dose and ingestion dose for 6 age groups; dose to fish. Countermeasures. External dose assessment takes into account exposure pathways as direct dose from the water body and dose from the shoreline deposits. The model makes use of external dose factors available in the literature, shielding factors applicable for the different situations considered, and mean exposure times. Countermeasures modelled: restriction of access to contaminated areas. For internal dose from ingestion, the exposure pathways considered are: ingestion of water, consumption of fish (prey, predator), consumption of crops irrigated by contaminated water (5 categories), and consumption of milk and meat from livestock (cow, sheep, and pig) watered with contaminated water or fed with contaminated crops. Countermeasures modelled: restrictions to water and food consumption, and restrictions to water use for irrigation, based on contamination levels or on user defined periods. Models for calculating concentrations of radionuclides in crops, soil and livestock products are based on a dynamic compartment structure based on validated models described in the specialised literature. The paper makes a summary description of the model, its applications and importance in a Decision Support System for the restoration of contaminated freshwater ecosystems, based on a Multiattribute approach. (author)

2000-01-01

220

AVES.NET: The Freshwater Dinoflagellates  

Science.gov (United States)

Hosted by AVES.NET, this website about Freshwater Dinoflagellates was created by Victor W. Fazio III and Dr. Susan Carty of Heidelberg College (Tiffin, Ohio). Two main attractions of this site are the Freshwater Dinoflagellate Image Archive, and the Recent Additions-Freshwater Dinoflagellate Images 2003 (from the 2003-04 winter field season). Individual Dinoflagellate image pages generally include a ventral view, dorsal view, or both, and the pages featuring species from Ohio include county distribution maps. Site visitors can email Dr. Carty for permission to use any of the images. The website also contains a List of Freshwater Dinoflagellates in Ohio, some of which link to the individual image pages. Additionally, the site offers a Review of Online Images of Freshwater Dinoflagellates including links to many other host sites, and a link to an online article by Dr. Susan Carty and Daniel E. Wujek entitled _A New Species of Peridinium and New Records of Dinoflagellates and Silica-Scaled Chrysophytes from Belize._ [NL

Fazio, Victor W. (1962-); Carty, Susan

 
 
 
 
221

Cellulolytic microbes in the Yanbaru, a subtropical rainforest with an endemic biota on Okinawa Island, Japan.  

UK PubMed Central (United Kingdom)

Cellulolytic microbes in the soil of the Yanbaru, a subtropical forest with an endemic biota, on Okinawa Island, were isolated and characterized in a search for novel microbial strains with biotechnological potential. Soil samples of the Yanbaru were suspended in sterilized water, inoculated on mineral salt agar overlaid with a filter paper as carbon source, and cultivated aerobically at 30 °C. After 2 weeks of cultivation, emerging colonies were isolated and subjected to phylogenetic and enzyme analyses. The phylogenetic analyses revealed bacterial and fungal isolates belonging to nine and three genera respectively. All isolates possessed cellulase activity, and several strains showed strong activity comparable to Trichoderma cellulase. Many isolates also exhibited xylanase activity.

Fujii K; Oosugi A; Sekiuchi S

2012-01-01

222

Applying DoE's Graded Approach for assessing radiation impacts to non-human biota at the Incl  

International Nuclear Information System (INIS)

In July 2002, The US Department of Energy (DOE) released a new technical standard entitled A Graded Approach for Evaluating Radiation Doses to Aquatic and Terrestrial Biota. DOE facilities are annually required to demonstrate that routine radioactive releases from their sites are protective of non-human receptors and sites are encouraged to use the Graded Approach for this purpose. Use of the Graded Approach requires completion of several preliminary steps, to evaluate the degree to which the site environmental monitoring program is appropriate for evaluating impacts to non-human biota. We completed these necessary activities at the Idaho National Laboratory (INL) using the following four tasks: (1) develop conceptual models and evaluate exposure pathways; (2) define INL evaluation areas; (3) evaluate sampling locations and media; (4) evaluate data gaps. All of the information developed in the four steps was incorporated, data sources were identified, departures from the Graded Approach were justified, and a step-by-step procedure for biota dose assessment at the INL was specified. Finally, we completed a site-wide biota dose assessment using the 2002 environmental surveillance data and an offsite assessment using soil and surface water data collected since 1996. These assessments demonstrated the environmental concentrations of radionuclides measured on and near the INL do not present significant risks to populations of non-human biota.

2006-01-01

223

Distribution and determination of Pb, Cd, Bi and Cu in the sea brine system: solution--colloidal particles--biota.  

Science.gov (United States)

The distribution of Pb, Cd, Bi, and Cu in Black Sea brine system (solution--colloidal particles--biota) produced in Burgas and Pomorie salterns is studied. The established distribution of the title elements among the brine components is as follows: Pb--25% in the salt solution, 30%--in colloidal particles, 45%--in biota (Halobacterium salinarium and microalgae Dunaliela salina); Cu--30% in the salt solution, 22%--in colloidal particles, 48%--in biota. Cd and Bi are not detected in biota. They are uniformly distributed (50%: 50%) between the salt solution and colloidal particles. Two procedures for analysis are developed. The first one is designed for determination of the total content of the studied metals in brine. It involves elimination of the biota interference by addition of ethanol, extraction and pre-concentration of the metals with NaDDC into CCl4 followed by FAAS determination. The second procedure intends determination of the elements in the separate components of the brine. It involves separation of the colloidal particles through centrifugation, separation of the studied elements from the resulting solution as dithiocarbamate complexes on a Millipore filter, dissolution of the retained metal species and subsequent FAAS analysis. PMID:16948432

Bozhkov, Ognyan; Tzvetkova, Christina; Russeva, Elena

224

Dispersion Of Crude Oil And Petroleum Products In Freshwater  

Science.gov (United States)

The objective of this research was to investigate the relationship between dispersion effectiveness in freshwater and the surfactant composition for fresh and weathered crude oil. Although limited research on the chemical dispersion of crude oil and petroleum products in freshwat...

225

Marine incursion: the freshwater herring of Lake Tanganyika are the product of a marine invasion into west Africa.  

Science.gov (United States)

The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25-50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics. PMID:18431469

Wilson, Anthony B; Teugels, Guy G; Meyer, Axel

2008-04-23

226

Marine incursion: the freshwater herring of Lake Tanganyika are the product of a marine invasion into west Africa.  

UK PubMed Central (United Kingdom)

The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25-50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics.

Wilson AB; Teugels GG; Meyer A

2008-01-01

227

137Cs in freshwater fish in Finland  

International Nuclear Information System (INIS)

The paper deals with an evaluation of the importance of Finnish freshwater fish as a source of 137Cs in the diet. Freshwater fish were analysed for 137Cs in 1982. The 137Cs concentration factors from water to edible fish were determined for the same year. The evaluation is based on an extensive surface water investigation performed from 1965 to 1967. Along with the continuous fallout monitoring since the beginning of the 1960'es, this material makes it possible to valuate the 137Cs levels in surface water right up to the 1980'es. In 1982 the Finns received an average of 90 Bq 137Cs from freshwater fish. This dose constitutes a quarter of the 137Cs uptake from the total food consumtion in Finland in 1982

1985-03-01

228

Freshwater exposure pathways in the Nordic countries  

International Nuclear Information System (INIS)

The report relates to a subproject under a Nordic project called ''Large reactor accidents - consequences and mitigating actions''. The report summarizes information available, primarily in the Nordic countries, on freshwater exposure pathways. Experimental and theoretical data concerning the deposition and run-off of the nuclides *sp90*Sr and*Sp137*Cs is presented. Internal exposure via drinking water and freshwater fish is dealt with, as well as external exposure due to swimming, boating, contact with fishing utensils and use of beach areas. In addition is exposure via irrigated agricultural products considered. (RF)

1984-01-01

229

Modeling transport and dilution of produced water and the resulting uptake and biomagnification in marine biota  

Energy Technology Data Exchange (ETDEWEB)

The paper explains the numerical modelling efforts undertaken in order to study possible marine biological impacts caused by releases of produced water from the Haltenbanken area outside the western coast of Norway. Acute effects on marine life from releases of produced water appear to be relatively small and confined to areas rather lose to the release site. Biomagnification may however be experienced for relatively low concentrations at larger distances from the release point. Such effects can he modeled by performing a step-wise approach which includes: The use of 3-D hydrodynamic models to determine the ocean current fields; The use of 3-D multi-source numerical models to determine the concentration fields from the produced water releases, given the current field; and The use of biologic models to simulate the behavior of and larvae (passive marine biota) and fish (active marine biota) and their interaction with the concentration field. The paper explains the experiences gained by using this approach for the calculation of possible influences on marine life below the EC{sub 50} or LC{sub 50} concentration levels. The models are used for simulating concentration fields from 5 simultaneous sources at the Haltenbank area and simulation of magnification in some marine species from 2 simultaneous sources in the same area. Naphthalenes and phenols, which are both present in the produced water, were used as the chemical substances in the simulations.

Rye, H.; Reed, M.; Slagstad, D. [and others

1996-12-31

230

Selenium accumulation in aquatic biota downstream of a uranium mining and milling operation  

Energy Technology Data Exchange (ETDEWEB)

Uranium mining and milling operations have the potential to release trace elements such as arsenic, molybdenum, nickel, selenium and uranium and ions (e.g., sulfate, ammonium) into the receiving aquatic ecosystem. The major implication of elevated environmental selenium is its propensity to accumulate in the aquatic food chain, potentially impairing fish reproduction. The objective of this study was to investigate the accumulation of selenium in the major compartments of aquatic ecosystems (lakes) upstream and downstream of a uranium mine in northern Saskatchewan, Canada. Selenium concentrations in aquatic biota were elevated in the exposure lake although water and sediment concentrations were low (0.43 {mu}g/L and 0.54 {mu}g/g dry weight, respectively). Biomagnification of selenium resulted in approximately 1.5 to 6 fold increase in the selenium concentration between plankton, invertebrates and fish. However, no biomagnification was observed between forage and predatory fish. Although some aquatic biota (e.g., forage fish) exceeded the lower limit of the proposed 3 to 11 {mu}g/g (dry weight) dietary toxicity threshold for fish, no adverse effects of selenium could be identified in this aquatic system. Continued environmental monitoring is recommended to avoid potential selenium impacts.

Muscatello, J.R. [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3 (Canada); Janz, D.M. [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3 (Canada); Department of Veterinary Biomedical Sciences, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4 (Canada)], E-mail: david.janz@usask.ca

2009-02-01

231

Climate change and the Israeli biota: little is known but much can be done  

Energy Technology Data Exchange (ETDEWEB)

Our understanding of the effect of climate changes on the Israeli biota, and hence on natural and man-affected ecosystems, depends on understanding the influence of the present climate on the determination of the current distribution and abundance of organisms. Israel is mostly inhabited by populations at the distributional boundaries of their species. It is plausible that these populations will be more resistant and will react more rapidly to climatic changes than populations of the same species at the core areas of their distributions. This proposed fast reaction enables using the Israeli biota effectively for (a) monitoring the effect of climate change on ecosystems, and (b) performing manipulative field and laboratory experiments with these populations for predicting future effects of climate change on ecosystems. Due to their adaptability and resistance, these Israeli populations constitute a biological and genetic resource for reconstruction and rehabilitation of ecosystems damaged by global climate change. Within Israel, the climatic transition zone between desert and non-desert regions, with its steep precipitation gradient across a short distance, should serve for large-scale and long-term field experiments, and function as a repository of genetic resources and as a live laboratory for experimenting with unorthodox management practices. 26 refs., 1 fig.

Safriel, U.N. [Hebrew University, Jerusalem (Israel). Science and Management Division

1993-09-01

232

Selenium accumulation in aquatic biota downstream of a uranium mining and milling operation  

International Nuclear Information System (INIS)

[en] Uranium mining and milling operations have the potential to release trace elements such as arsenic, molybdenum, nickel, selenium and uranium and ions (e.g., sulfate, ammonium) into the receiving aquatic ecosystem. The major implication of elevated environmental selenium is its propensity to accumulate in the aquatic food chain, potentially impairing fish reproduction. The objective of this study was to investigate the accumulation of selenium in the major compartments of aquatic ecosystems (lakes) upstream and downstream of a uranium mine in northern Saskatchewan, Canada. Selenium concentrations in aquatic biota were elevated in the exposure lake although water and sediment concentrations were low (0.43 ?g/L and 0.54 ?g/g dry weight, respectively). Biomagnification of selenium resulted in approximately 1.5 to 6 fold increase in the selenium concentration between plankton, invertebrates and fish. However, no biomagnification was observed between forage and predatory fish. Although some aquatic biota (e.g., forage fish) exceeded the lower limit of the proposed 3 to 11 ?g/g (dry weight) dietary toxicity threshold for fish, no adverse effects of selenium could be identified in this aquatic system. Continued environmental monitoring is recommended to avoid potential selenium impacts

2009-02-01

233

Spatial relationships among soil biota in a contaminated grassland ecosystem at Aberdeen Proving Ground, Maryland  

Energy Technology Data Exchange (ETDEWEB)

Spatial relationships among soil nematodes and soil microorganisms were investigated in a grassland ecosystem contaminated with heavy metals in the US Army`s Aberdeen Proving Ground. The study quantified fungal and bacterial biomass, the abundance of soil protozoa, and nematodes. Geostatistical techniques were used to determine spatial distributions of these parameters and to evaluate various cross-correlations. The cross-correlations among soil biota numbers were analyzed using two methods: a cross general relative semi-variogram and an interactive graphical data representation using geostatistically estimated data distributions. Both the visualization technique and the cross general relative semi-variogram and an interactive graphical data representation using geostatistically estimated data distributions. Both the visualization technique and the cross general relative semi-variogram showed a negative correlation between the abundance of fungivore nematodes and fungal biomass, the abundance of bacterivore nematodes and bacterial biomass, the abundance of omnivore/predator nematodes and numbers of protozoa, and between numbers of protozoa and both fungal and bacterial biomass. The negative cross-correlation between soil biota and metal concentrations showed that soil fungi were particularly sensitive to heavy metal concentrations and can be used for quantitative ecological risk assessment of metal-contaminated soils. This study found that geostatistics are a useful tool for describing and analyzing spatial relationships among components of food webs in the soil community.

Kuperman, R. [Army ERDEC, Aberdeen Proving Ground, MD (United States); Williams, G. [Argonne National Lab., IL (United States); Parmelee, R. [Ohio State Univ., Columbus, OH (United States)

1995-12-31

234

Selenium accumulation in aquatic biota downstream of a uranium mining and milling operation.  

Science.gov (United States)

Uranium mining and milling operations have the potential to release trace elements such as arsenic, molybdenum, nickel, selenium and uranium and ions (e.g., sulfate, ammonium) into the receiving aquatic ecosystem. The major implication of elevated environmental selenium is its propensity to accumulate in the aquatic food chain, potentially impairing fish reproduction. The objective of this study was to investigate the accumulation of selenium in the major compartments of aquatic ecosystems (lakes) upstream and downstream of a uranium mine in northern Saskatchewan, Canada. Selenium concentrations in aquatic biota were elevated in the exposure lake although water and sediment concentrations were low (0.43 microg/L and 0.54 microg/g dry weight, respectively). Biomagnification of selenium resulted in approximately 1.5 to 6 fold increase in the selenium concentration between plankton, invertebrates and fish. However, no biomagnification was observed between forage and predatory fish. Although some aquatic biota (e.g., forage fish) exceeded the lower limit of the proposed 3 to 11 microg/g (dry weight) dietary toxicity threshold for fish, no adverse effects of selenium could be identified in this aquatic system. Continued environmental monitoring is recommended to avoid potential selenium impacts. PMID:19036410

Muscatello, J R; Janz, D M

2008-11-25

235

Uptake of ?-emitting radionuclides by aquatic biota exposed to contaminated water before and after passage through the ground  

International Nuclear Information System (INIS)

Three experimental systems were designed to investigate the differential accumulation of radionuclides by biota from low-level aqueous effluents after passage through the ground. One system received river water (control), one received dilute low-level radioactive effluents (trench), and the third received the low-level effluents after it had percolated through about 260 m or porous gravel (springs). Biota studied included filamentous green algae, clams (Corbicula), goldfish (Carassius auratus), carp (Cyprinus carpio), and Veronica. Trophic level differences in accumulation of the various radionuclides from the diluted trench water were not consistent but generally followed the pattern algae > goldfish > molluscs > carp. Cobalt-60 was accumulated to the highest level of any radionuclide, and accumulation levels at the three sites were directly related to the concentration of 60Co in the water. Manganese-54, 59Fe, and 106Ru were also accumulated to measurable levels in biota at the springs site indicating their bioavailability after passage through the ground.

1984-01-01

236

Organochlorine pesticides in sediment and biota in the coastal region to the South of the Pinar del Rio Province, Cuba  

International Nuclear Information System (INIS)

[en] A study was conducted to assess the levels of persistent organochlorine pesticides in the coastal region near to a large rice field to the south of the Pinar del Rio Province in Cuba. Samples of sediment and biota (Isognomon alatus) were taken periodically over a period of 14 months. Analysis of organochlorines, polychlorinated biphenyls and other related compounds was done using gas chromatography-electron capture detection with a mean recovery of 87% and a detection limit of 0.25 ?g/kg. Only DDT, DDE and DDD were found in the sediment and biota samples, with small differences in concentration between sampling sites during the dry season. After the rainy season began, the residues in sediment were very low, while the concentrations in biota remained comparatively unchanged, ranging from 11.2 to 23.8 ?g/kg total DDT. (author). 4 refs, 2 tabs

1997-01-01

237

Sulfate reduction in freshwater peatlands  

Energy Technology Data Exchange (ETDEWEB)

This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the anaerobic decomposition in a boreal peatland. The relative importance of sulfate reduction and methane production for the anaerobic decomposition was studied in a small raised bog situated in the boreal zone of southern Sweden. Depth distribution of sulfate reduction- and methane production rates were measured in peat sampled from three sites (A, B, and C) forming an minerotrophic-ombrotrophic gradient. SO{sub 4}{sup 2-} concentrations in the three profiles were of equal magnitude and ranged from 50 to 150 {mu}M. In contrast, rates of sulfate reduction were vastly different: Maximum rates in the three profiles were obtained at a depth of ca. 20 cm below the water table. In A it was 8 {mu}M h{sup -1} while in B and C they were 1 and 0.05 {mu}M h{sup -1}, respectively. Methane production rates, however, were more uniform across the three nutrient regimes. Maximum rates in A (ca. 1.5 {mu}g d{sup -1} g{sup -1}) were found 10 cm below the water table, in B (ca. 1.0 {mu}g d{sup -1} g{sup -1}) in the vicinity of the water table, and in C (0.75 {mu}g d{sup -1} g{sup -1}) 20 cm below the water table. In all profiles both sulfate reduction and methane production rates were negligible above the water table. The areal estimates of methane production for the profiles were 22.4, 9.0 and 6.4 mmol m{sup -2} d{sup -1}, while the estimates for sulfate reduction were 26.4, 2.5, and 0.1 mmol m{sup -2} d{sup -1}, respectively. The calculated turnover times at the sites were 1.2, 14.2, and 198.7 days, respectively. The study shows that sulfate reducing bacteria are important for the anaerobic degradation in the studied peatland, especially in the minerotrophic sites, while methanogenic bacteria dominate in ombrotrophic sites Examination paper. 67 refs, 6 figs, 3 tabs

Oequist, M.

1996-12-31

238

CROATIAN FRESHWATER FISHERIES IN 1997  

Directory of Open Access Journals (Sweden)

Full Text Available Data on the production and fish catch according to species, on the surface of the fish ponds, on the means of fish catching and on the distribution of the production and the catch in 1997 is presented. The surface area used for production of fish has decreased for 836 ha or 8.40%. The total fish amount was bigger for 477 tons, or 10,52%. The feeding coefficient is 2.6 kg decreased 35% for in comparison to the bigger compared to the previous year. The amount of the fertilizer used is bigger for 37.30%. The fry carp growing ponds make up 6.50% of the total fish pond surfaces, the young carp ponds 22.04/0, and the ponds with consumption fish 70.31%. The total amount in the carp ponds was 446 kg/ha, and in the trout ponds it was 160.8 tons/ha. The most produced fish species is the carp with 79.32%, followed by the trout with 11.50%, the herbivorous fish with 4.25%, while all the other fish species make up 4.93% of the entire production. In the structure of herbivorous fish the grass carp is leading with 69,23%, followed by the big head carp with 29.74% and the silver carp with 1.03%. Compared to the previous year the production of the carp, grass carp and tench is increased. Fish catch in open waters has decreased by 5.53% in comparison to the previous year. In the production and catch of the total freshwater fish, carp made up 75.34%, herbivorous fish made up 3.89%, trout 10.66%, sheat fish, pike perch and pike 2.70% and all other fish species 7.41%. As far as the distribution of production and catch of fish is concerned, 52,80% were sold on the market, 37.94% were used for reproduction (stocking the fish farms), mortality was 1.43%, and for personal use (sports fishing) 7.83%. The number of fisheries workers has decreased for 8.17%, and the production per worker is bigger for 22.25%, compared to the previous year. Average production per worker was 7.17% tons of fish.

Mirko Turk

1998-01-01

239

CROATIAN FRESHWATER FISHERIES IN 1996.  

Directory of Open Access Journals (Sweden)

Full Text Available Data on the production and fish catch according to species, on the surface of the fish ponds, on the means of fish catching and on the distribution of the production and the catch in 1996 is presented. The surface area used for production of fish has decreased by 1357 ha or 11.99%. The total fish amount has decreased by 1,921.00 tons or 29.76%. The feeding coefficient is 4 kg (33.33%) bigger compared to the previous year. The amount of the fertilizer used has decreased by 18.79%. The fry carp growing ponds make up 5.99% of the total fish pond surfaces, the young carp ponds 21.13%, and the ponds with consumption fish 71.53%. The total fish amount in the carp ponds was 376 kg/ha, and in the trout ponds it was 146.6 tons/ha. The most produced fish species is the carp with 82.21 %, followed by the trout with 8.57%, the herbivorous fish with 4.78%, while all the other fish species make up 4.44% of the entire production. In the structure of herbivorous fish the grass carp is leading with 64,28%, followed by the big head carp with 26.02% and the silver carp with 9.70%. Compared to the previous year the production of the trout and tench has somewhat increased, while the production of all the other species of fish has decreased. Fish catch in open waters has increased by 19.23% in comparison to the previous year. In the production and catch of the total freshwater fish, carp made up 77.46%, the herbivorous fish made up 4.32%, trout 4.32%, sheat fish, pike perch and pike 2.99% and all other fish species 7.36%. As far as the distribution of production and catch is concerned, 46.91% were sold on the market, 39.19% were used for reproduction (stocking the fish farms), mortalities were 6.23%, and for personal use (sports fishing) 7.67% was used. The number of fisheries workers has decreased by 17.75%, and the production per worker has also decreased by 26.62%, compared to the previous year. Average production per worker was 5.87 tons of fish.

Mirko Turk

1997-01-01

240

Sulfate reduction in freshwater peatlands  

International Nuclear Information System (INIS)

This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the anaerobic decomposition in a boreal peatland. The relative importance of sulfate reduction and methane production for the anaerobic decomposition was studied in a small raised bog situated in the boreal zone of southern Sweden. Depth distribution of sulfate reduction- and methane production rates were measured in peat sampled from three sites (A, B, and C) forming an minerotrophic-ombrotrophic gradient. SO42- concentrations in the three profiles were of equal magnitude and ranged from 50 to 150 ?M. In contrast, rates of sulfate reduction were vastly different: Maximum rates in the three profiles were obtained at a depth of ca. 20 cm below the water table. In A it was 8 ?M h-1 while in B and C they were 1 and 0.05 ?M h-1, respectively. Methane production rates, however, were more uniform across the three nutrient regimes. Maximum rates in A (ca. 1.5 ?g d-1 g-1) were found 10 cm below the water table, in B (ca. 1.0 ?g d-1 g-1) in the vicinity of the water table, and in C (0.75 ?g d-1 g-1) 20 cm below the water table. In all profiles both sulduction rates were negligible above the water table. The areal estimates of methane production for the profiles were 22.4, 9.0 and 6.4 mmol m-2 d-1, while the estimates for sulfate reduction were 26.4, 2.5, and 0.1 mmol m-2 d-1, respectively. The calculated turnover times at the sites were 1.2, 14.2, and 198.7 days, respectively. The study shows that sulfate reducing bacteria are important for the anaerobic degradation in the studied peatland, especially in the minerotrophic sites, while methanogenic bacteria dominate in ombrotrophic sites Examination paper. 67 refs, 6 figs, 3 tabs.

1996-01-01

 
 
 
 
241

Radionuclide accumulation by aquatic biota exposed to contaminated water in artificial ecosystems before and after its passage through the ground  

International Nuclear Information System (INIS)

This study was designed to investigate the comparative accumulation of radionuclides from contaminated water in artificial ecosystems before and after the water's passage through the ground. Fish, clams, algae, and an emergent vascular plant were experimentally exposed to mixtures of radionuclides in three aqueous streams. Two streams consisted of industrial water discharged directly into a leaching trench, and the same water after it had migrated through the ground for a distance of 260 meters. The third stream was river water, which served as a background or control. Biota exposed to river water in the control stream had very low concentrations of 60Co, less than 3 pCi per gram dry weight (pCi/g DW). Other radionuclides were essentially unmeasurable. Biota exposed to trench water accumulated very high relative concentrations of 60Co. Biota exposed to trench water also had measurable concentrations of 155Eu, 144Ce, 141Ce, 125Sb, 124Sb, 103Ru, 106Ru, 137Cs, 95Zr, 95Nb, 58Co, 54Mn, 59Fe, 65Zn, 90Sr, /sup 239,240/Pu, and 238Pu. Biota exposed to ground water had concentrations of 60Co that ranged between 50 and 1200 pCi/g DW. Fish flesh had the lowest concentration of 60Co and algae the highest. Strontium-90 was measured in the tissues of aquatic biota at concentrations ranging between 360 pCi/g DW in clam flesh to 3400 pCi/g DW in leaves and stems of Veronica. Leaves and fruits of tomato plants rooted in the ground water accumulated 90Sr at concentrations of 160 pCi in fruits and 4200 pCi in leaves. Data indicate that 60Co and 90Sr migrated through the ground along with ground-water flow and were available to all classes of aquatic biota and tomato plants rooted in the water via root uptake, sorption, and food chain transfers. 8 refs., 4 figs., 6 tabs.

242

Changes to the ocular biota with time in extended- and daily-wear disposable contact lens use.  

Science.gov (United States)

Gram-negative bacteria may play a role in the etiology of certain soft contact lens (SCL)-related diseases. Contact lens (CL) wear may modify the normal ocular biota, providing a more favorable environment for potential pathogens. This study reports temporal changes in ocular biota in daily-wear (DW) and extended-wear (EW) disposable SCL use in experienced and neophyte wearers. Lid margin and bulbar conjunctival biota were sampled prior to CL fitting in 26 previous DW SCL users, 18 previous EW SCL users, and 26 neophytes. Wearers were fitted with an etafilcon A CL in one eye and a polymacon CL in the fellow eye. Lenses were worn on a daily basis by the 26 previous DW SCL wearers and on an EW basis by the remaining 44 subjects. The ocular biota was further sampled after 1, 3, 6, 9, and 12 months of wear. The ocular biota consisted of coagulase-negative staphylococci, Corynebacterium spp., Micrococcus spp., and Propionibacterium spp. Potential pathogens were rarely isolated at baseline. No significant trend of increasing ocular colonization was shown for extended CL wear. Lid and conjunctival colonization increased with DW SCL use (P < 0.001), although this increase occurred for nonpathogenic species only. Fewer potential pathogens were isolated from DW SCL than from EW SCL users (P < 0.05). The lid margin consistently showed greater colonization than the conjunctiva and may be a source of potential pathogens during CL wear. Hydrogel CL wear appears to modify the ocular biota. An increased number of commensal organisms were present in DW SCL use. EW SCL use altered the spectrum of organisms isolated. These alterations may suppress the normal ocular defense mechanisms and may be relevant in the pathogenesis of CL-related disease.

Stapleton, F; Willcox, M D; Fleming, C M; Hickson, S; Sweeney, D F; Holden, B A

1995-01-01

243

Molecular identification, typing and traceability of cyanobacteria from freshwater reservoirs.  

Science.gov (United States)

In order to assess the potential of several molecular targets for the identification, typing and traceability of cyanobacteria in freshwater reservoirs, molecular techniques were applied to 118 cyanobacterial isolates mostly sourced from Portuguese freshwater reservoirs and representative of three orders of cyanobacteria: Chroococcales (54), Oscillatoriales (15) and Nostocales (49). The isolates were previously identified by morphological methods and subsequently characterized by composite hierarchical cluster analysis of STRR and LTRR (short and long tandemly repeated repetitive sequences) PCR fingerprinting profiles. Representative isolates were selected from each cluster and their molecular identification, at the species level, was obtained or confirmed by phylogenetic positioning using 16S rRNA gene and rpoC1 phylogenies. A highly congruent association was observed between STTR- and LTRR-based clusters and taxonomic affiliation, revealing the usefulness of such PCR fingerprinting profiles for the identification of cyanobacteria. Composite analysis of hierarchical clustering of M13 and ERIC PCR fingerprints also appeared suitable for strain typing and traceability within a reservoir, indicating its potential for use in cyanobacterial monitoring, as a quality management control. Based on Simpson (D) and Shannon-Wiener (J') indices a high diversity was observed within all species, with Planktothrix agardhii showing the lowest diversity values (D=0.83; J'=0.88) and Aphanizomenon flos-aquae the highest ones (D=J'=0.99). A diagnostic key based on 16S-ARDRA, ITS amplification and ITS-ARDRA for identification purposes is also presented. PMID:19202113

Valério, Elisabete; Chambel, Lélia; Paulino, Sérgio; Faria, Natália; Pereira, Paulo; Tenreiro, Rogério

2009-02-01

244

Acute toxicity of heavy metals towards freshwater ciliated protists  

International Nuclear Information System (INIS)

The acute toxicity of five heavy metals to four species of freshwater ciliates (Colpidium colpoda, Dexiotricha granulosa, Euplotes aediculatus, and Halteria grandinella) was examined in laboratory tests. After exposing the ciliates to soluble compound of cadmium, copper, chromium, lead, and nickel at several selected concentrations, the mortality rate was registered and the LC5 values (with 95% confidence intervals) were calculated. Large differences appeared in sensitivities of the four species to the metals. H. grandinella showed the highest sensitivity for cadmium (0.07 mg l-1, LC5) and lead (0.12 mg l-1, LC5), whilst E. aediculatus showed the highest sensitivity for nickel (0.03 mg l-1, LC5). The comparison with data obtained with other species indicate that Halteria grandinella and Euplotes aediculatus are excellent and convenient bioindicator for evaluating the toxicity of waters and wastewaters polluted by heavy metals. The short time (24 h) and simplicity of the test procedure enable this test to be used in laboratory studies. - Ciliated protozoa are suitable bioindicators of heavy metal pollution in freshwater environments.

2006-01-01

245

Molecular identification, typing and traceability of cyanobacteria from freshwater reservoirs.  

UK PubMed Central (United Kingdom)

In order to assess the potential of several molecular targets for the identification, typing and traceability of cyanobacteria in freshwater reservoirs, molecular techniques were applied to 118 cyanobacterial isolates mostly sourced from Portuguese freshwater reservoirs and representative of three orders of cyanobacteria: Chroococcales (54), Oscillatoriales (15) and Nostocales (49). The isolates were previously identified by morphological methods and subsequently characterized by composite hierarchical cluster analysis of STRR and LTRR (short and long tandemly repeated repetitive sequences) PCR fingerprinting profiles. Representative isolates were selected from each cluster and their molecular identification, at the species level, was obtained or confirmed by phylogenetic positioning using 16S rRNA gene and rpoC1 phylogenies. A highly congruent association was observed between STTR- and LTRR-based clusters and taxonomic affiliation, revealing the usefulness of such PCR fingerprinting profiles for the identification of cyanobacteria. Composite analysis of hierarchical clustering of M13 and ERIC PCR fingerprints also appeared suitable for strain typing and traceability within a reservoir, indicating its potential for use in cyanobacterial monitoring, as a quality management control. Based on Simpson (D) and Shannon-Wiener (J') indices a high diversity was observed within all species, with Planktothrix agardhii showing the lowest diversity values (D=0.83; J'=0.88) and Aphanizomenon flos-aquae the highest ones (D=J'=0.99). A diagnostic key based on 16S-ARDRA, ITS amplification and ITS-ARDRA for identification purposes is also presented.

Valério E; Chambel L; Paulino S; Faria N; Pereira P; Tenreiro R

2009-02-01

246

Mapping spatial variability in redox conditions at the landscape scale using the stable isotopic compositions of biota  

International Nuclear Information System (INIS)

We are attempting to use the ?15N, ?13C and ?34S of biota in marshes and riverine systems as indicators of local environmental conditions that may impact water salinity. The theoretical basis of this study is that the isotopic compositions of plankton and non-fixing plants reflect to a large extent the isotopic compositions of the dissolved N, C and S in the environment that is being utilized by the biota, as modified by various possible fractionating mechanisms in the plants

1999-01-01

247

An international comparison of models and approaches for the estimation of the radiological exposure of non-human biota  

International Nuclear Information System (INIS)

Over the last decade a number of models and approaches have been developed for the estimation of the exposure of non-human biota to ionising radiations. In some countries these are now being used in regulatory assessments. However, to date there has been no attempt to compare the outputs of the different models used. This paper presents the work of the International Atomic Energy Agency's EMRAS Biota Working Group which compares the predictions of a number of such models in model-model and model-data inter-comparisons.

2008-01-01

248

Accumulation and toxicokinetics of fluoranthene in sediment bioassays with freshwater amphipods  

Energy Technology Data Exchange (ETDEWEB)

Two freshwater amphipods, Hyalella azteca and Diporeia sp., were exposed to sediment spiked with radiolabeled fluoranthene at nominal concentrations of 0.1 (trace) to 1,270 nmol fluoranthene/g dry weight. In two experiments, uptake kinetics and mortality were determined over 30-d exposures. Concentrations of fluoranthene in sediment and pore water were also measured. Mean survival of H. azteca was generally high, greater than 90% after 10 or 16 d, and greater than 74% after 30 d. Mean survival was lower for Diporeia, 14% after a 30-d exposure to the highest sediment concentration in experiment 1, and 53% in experiment 2. Tissue concentrations in Diporeia were as high as 2 to 4 {micro}mol/g wet weight, a body burden that could be expected to result in death by narcosis. Hyalella azteca did not typically accumulate more than 1 {micro}mol/g wet weight, which is consistent with the lower observed mortality. Apparent steady-state biota-sediment accumulation factors (BSAFs, lipid- and organic-carbon-normalized) for sediment concentrations other than trace level tended to be higher for Diporeia than for H. azteca. The BSAFs for trace levels tended to be lower for both species in comparison to higher sediment concentrations. For both organisms, the internal concentration based on body residue was a more reliable indicator of toxicity than were equilibrium partitioning predictions.

Driscoll, S.K.; Harkey, G.A.; Landrum, P.F. [National Oceanic and Atmospheric Administration, Ann Arbor, MI (United States). Great Lakes Environmental Research Lab.

1997-04-01

249

Bioaccumulation of polybrominated diphenyl ethers by the freshwater benthic amphipod Gammarus pulex.  

UK PubMed Central (United Kingdom)

This study reports on the relationship between polybrominated diphenyl ether (PBDE) levels in water, sediment, and the benthic macroinvertebrate Gammarus pulex, which plays a major ecological role in freshwater ecosystems. Samples were taken in a periurban watershed (near Paris, France), and PBDEs were systematically detected in sediment (?727 ng g(-1) OC) and G. pulex (?264 ng g(-1) lipids). PBDEs were also occasionally detected in the water column at low levels (? PBDEs < 1.5 ng L(-1)). The log values of bioaccumulation factors were in the range 7.8 ± 0.1-8.3 ± 0.4 L kg(-1) for tetra- and penta-BDEs, which were the only ones quantified in the dissolved phase of river water. Meanwhile, levels of individual tri- to hepta-PBDE congeners in G. pulex generally positively correlated with sediment levels, suggesting an equilibrium situation. Biota-to-sediment accumulation factors (BSAFs) of tri-hepta BDEs were congener specific and were in the range 0.5 ± 0.3-2.6 ± 1.2. For several PBDEs, BSAF values deviated from the expected range, likely because of in vivo metabolism.

Tlili K; Labadie P; Bourges C; Desportes A; Chevreuil M

2012-07-01

250

Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean  

International Nuclear Information System (INIS)

The Subantarctic Kerguelen Islands (49oS, 70oE) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g-1 lipid, and dioxin-like PCB was 19 and 69 ng g-1 lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels. - Highlights: ? First assessment of PCB contamination of biota in Kerguelen Islands, Sub-Antarctica. ? PCB bioaccumulation level in trout varies from very high to undetectable. ? Habitat and morphotype are the most influential factors on the variability. ? Distribution pattern of PCBs in the muscle of fish is morphotype dependent. - Salmonids in hydrosystems of the Kerguelen Islands (Southern Ocean) show a high PCB bioaccumulation.

2011-01-01

251

Toxicity of vanadium to different freshwater organisms  

Energy Technology Data Exchange (ETDEWEB)

The aim of this study is to determine the acute and subchronic toxicity of vanadium for various species of freshwater fish. The long-term toxicity and the effect of vanadium on the reproduction of Daphnia magna is also evaluated and compared with the toxicity of other metals.

Beusen, J.M.; Neven, B.

1987-08-01

252

Scientific Assessment of Freshwater Harmful Algal Blooms.  

Science.gov (United States)

Freshwater harmful algal blooms (HABs) are comprised of algae that either create health hazards for humans or animals through the production of toxins or bioactive compounds or that cause deterioration of water quality through the build-up of high biomass...

B. T. Walton C. B. Lopez E. B. Jewett H. K. Hudnell Q. Dortch

2008-01-01

253

Effects of pollution on freshwater invertebrates  

Energy Technology Data Exchange (ETDEWEB)

The biological effects of acid rain, chlorination, heavy metals and other forms of pollution on freshwater invertebrates are examined in this review. Several methods for evaluating chronic toxicity to pesticide residues and synthetic fuels components are reviewed. The effects of pollutants is reviewed in detail for cladocera, amphipods, isopods, decapods, aquatic insects, molluscs, worms, and protozoa.(KRM)

Buikema

1982-06-01

254

Cadmium and zinc accumulation by freshwater crayfish  

Energy Technology Data Exchange (ETDEWEB)

A theoretical compartment model for the uptake of cadmium and zinc by freshwater crayfish was used to study the relative importance of food and water as uptake vectors for the two elements. Two concentrations of cadmium and zinc combined, and a control, element-free environment were utilized. Rate constants of cadmium uptake from food and water were measured.

Giesy, J.P.; Bowling, J.W.; Kania, H.J.

1980-01-01

255

Carbon-14 Specific Activity Model Validation for Biota in Wetland Environments  

International Nuclear Information System (INIS)

In many cases, contaminants, such as radionuclides, can show highly localized spatial distributions in natural systems. Therefore, a key question for environmental assessment and monitoring becomes, how can these localized distributions of contaminants in the environment lead to organism exposure, and ultimately, the potential for effects to receptor biota? To address this question, an important first step is to conduct field surveys at sites of interest to map out the spatial distribution and extent of contaminants in areas that are being occupied and utilized by resident receptor biota. Work can then be conducted to establish predictive relationships between contaminant concentrations in biota tissues and those in environmental media with which biota interact, to gain an understanding of how representative ambient contaminant concentrations are of biota exposure. The objectives of this study were: - To conduct a field survey in a wetland ecosystem to characterize the spatial distribution of carbon- 14 (14C), a radionuclide with dynamics in natural systems that can be described using a specific activity model; and - To determine whether 14C concentrations in environmental media reflect those measured in tissues of resident flora and fauna. A detailed field campaign was carried out in summer 2001 to characterize the spatial distribution and areal coverage of 14C in Duke Swamp, a wetland ecosystem on Atomic Energy of Canada Limited (AECL)'s Chalk River Laboratories (CRL) site that receives 14C through releases from an up-gradient Waste Management Area (WMA), primarily through groundwater influx. Sampling of surface vegetation (dominantly comprised of Sphagnum moss) was conducted at a total of 69 locations, with complementary sampling of air, soil, fungi, aerial insects, ground-dwelling insects, amphibians, small mammals and snakes being carried out at a subset of five locations with varying 14C concentrations. Concentrations of 14C in resident Duke Swamp biota were compared to levels measured in environmental media (including moss, soil and air) to determine whether concentrations in such media reflect animal exposure, for application in routine environmental monitoring programs on the CRL site. In general, for most types of receptor animals, 14C specific activities were found to be similar to or less than those measured in air, soil and surface vegetation at all locations sampled, suggesting that in most cases, estimates of 14C levels in animals could either be realistically or conservatively predicted based on the values measured in environmental media. In the case of fungi, receptor-to-media 14C specific activity ratios fell between 0.04 and 0.23 relative to air, between 0.03 and 0.70 relative to soil, and between 0.078 and 0.31 relative to moss. Small mammal specific activities also generally fell well below those that would be predicted based on specific activities measured in environmental media, with ratios ranging from 0.11 to 0.36 relative to air, from 0.17 to 0.85 relative to soil and from 0.21 to 0.58 relative to moss. Similar ratios were also established for snakes; however, a notable exception occurred for amphibians, a type of animal that tends to spend relatively more time in aquatic environments than the other species tested. In the case of Duke Swamp amphibians, animal-to-air 14C specific activity ratios ranged from 0.40 to 2.3, animal-to-soil ratios ranged from 0.81 to 3.4 and animal-to-moss ratios ranged from 1.5 to 2.4. These higher 14C levels in amphibians relative to the environmental media may be due to increased 14C exposure of aquatic or amphibious animals that occupy systems receiving inputs via groundwater. In such systems, 14C is incorporated in aquatic plants and animals, and later transferred to higher predatory species, such as amphibians, that consume them. Therefore, with the exception of amphibians and other aquatic receptor species, it is reasonable to estimate concentrations of 14C in receptor biota in wetland environments like Duke Swamp at CRL, based on measurements of 14C in environm

2008-01-01

256

Environmental Risk assessment by multi-bio marker responses in aquatic biota of three trophic levels in a lake of the Mexican Central Plateau  

International Nuclear Information System (INIS)

Aquatic ecosystems continually are impacted by wastewater and lixiviation of the adjacent areas. The inputs of xenobiotics generate complex mixtures that provoke adverse effects in the aquatic biota. The use of a battery of bio markers for the toxic effect assessment of xenobiotics in the aquatic biota is usefully for the environmental risk assessment (ERA). (Author)

2008-09-00

257

Environmental Risk assessment by multi-bio marker responses in aquatic biota of three trophic levels in a lake of the Mexican Central Plateau  

Energy Technology Data Exchange (ETDEWEB)

Aquatic ecosystems continually are impacted by wastewater and lixiviation of the adjacent areas. The inputs of xenobiotics generate complex mixtures that provoke adverse effects in the aquatic biota. The use of a battery of bio markers for the toxic effect assessment of xenobiotics in the aquatic biota is usefully for the environmental risk assessment (ERA). (Author)

Lopez-Lopez, E.; Sedeno-Diaz, J. E.

2009-07-01

258

CROATIAN FRESHWATER FISHERIES IN 1994  

Directory of Open Access Journals (Sweden)

Full Text Available Data on the production and catch of fish according to species, on the surface of the fish ponds, on the means of fish catching and on the distribution of the product and catch in 1994 is presented. The surface area used for production of fish has decreased by 274 ha or 2,51%. The total amount of fish has decreased by 1.263 tons or 14,78%. The highest production of fish was reached by the fish farm Donji Miholjac with 1.231 kg/ha. The feeding coefficient is 3,10 kg. Only on one fish farm was the feeding coefficient less than 2.0 kg (1,40 and on two large farms this coefficient was greater than 5,00 kg. The main fish food is still wheat followed by corn. The amount of fertilizer used was decreased by 14,40%. The fry carp growing ponds make up 0,92% of the surface area of the entire fish farm, the young carp ponds 21,77% and the culturing ponds for consumption fish 76,55%. The total amount of fish in the carp ponds was 660 kg/ha, and in the trout ponds it was 123.4 tons/ha. The carp is the highest produced fish with 80, 35%, then the herbivorous fish with 5,65 and all other fish make up 14% of the total production. In the structure of herbivorous fish the grass carp is leading with 54, 70%, followed by the big head carp with 25,54% and the silver carp with 19,76%. In comparison with the previous year the production of "all other fish- has significantly increased (287%), and sheat fish 18,90%, while the production of trench has decreased (71%). Fish catch in open waters has increased by 20,57% in comparison to the previous year. Carp made up 78,07% of the total production and catch of freshwater fish, the herbivorous fish made up 5,40%, trout 4,38%, the sheat fish, pike perch and pike 2,86% and all other fish species 9,28%. As far as the distribution of production and catch, 51,60% were sold on the market, 37,54% were used for reproduction (stocking the fish farms) , mortalities were 6,35% and for personal use (sports fishing) 4,50% was used. The number of fisheries workers decreased by 10,72% and the production per worker decreased by 3,12% in comparison to the previous year. According to each worker their was an average production of 9,00 tons of fish. In 1994 the highest production of fish was reached in Garešnica with 14,70 tons of fish per worker.

Mirko Turk

1995-01-01

259

CROATIAN FRESHWATER FISHERIES IN 1995  

Directory of Open Access Journals (Sweden)

Full Text Available The data on the production and catch of fish according to sorts, pond ackerage, fishing means as well as the distribution of production and catch in 1995 have been stated in the paper. Ackerages used for the fish production have been increased by 1710 acres or 6.51%; total fish prinos* is less for 1,252 tons or 17.05%. The highest production of fish was reched by the fish farm Donji Miholjac with 859 kg/ha. A nutritive coefficient is 3.0 kg and it is less by 3.22% compared with the previous year. The nutritive coefficient is less than 2.0 kg in three fish-farms but it is greater than 4.0 kg in five large fish farms. Mostly corn but also wheat dominate in fish nutrition. The fertilizers consumption has been reduced by 14.53%. Of total pond ackerage, growing fish farms occupy 1.25%, new fish farms occupy 17.90% and consumptive fish farms occupy 79.64%. Total fish production in carp ponds is 507 kg/ha and 136.1 ton/ha in trout ponds. With 84.33%, carp is the mostly produced fish sorts, herbivore fish follow it with 3.89% and the production of all other fish makes 11.78% of the total. With 83.97%, grass carp takes the first place in the structure of herbivore fish. It is followed by the big head carp with 9.28% and silver carp with 6.75%. The trout production has been slightly increased by 6. 3%. Pike has appeared again and all other fish sorts has been reduced. Fish catch in open water has been increased by 7.06% compared with the previous year. When we sum up total production and catch of fresh-water fish, we can conclude that carp contributes with 81.08%; herbivore fish with 3.67%; trouts with 5.53%; sheat-fish, pike-perch and pike with 2.74% and all other fish sorts with 6.98%. As to the distribution of production and catch, there has been 49.02% sold on markets, 38.02% has been spent on farm reproduction (set back in ponds), the percentage of mortalities is 7.90%. Sport fishers have spent 5.06% of fish. The number of employees has been reduced by 12.05% and fish production per employee has also been reduced by 1.10% compared with the previous year. It has been produced 8.0 tons of fish per employee. In 1995, the production has been greatest in Dragani?i: 15.60 tons of fish per employee.

Mirko Turk

1996-01-01

260

Investigation of manganese in salt- and freshwater pearls  

Energy Technology Data Exchange (ETDEWEB)

The trace element distribution in natural and cultured pearls is analysed by micro-PIXE, cathodoluminescence (CL) microscopy and spectroscopy and electron spin resonance (ESR) spectroscopy to develop a new method to distinguish cultured from natural pearls. These different kinds of pearls can be identified by their manganese content and its distribution in aragonite and calcite structure, respectively. Manganese content of natural freshwater pearls from Persian Gulf was compared to that of natural freshwater pearls from the Mississippi river (USA). Moreover manganese content of tissue-graft freshwater pearls from Chansu (China) was compared to that of natural freshwater pearls from the Mississippi river (USA). It was proved that the Chinese freshwater tissue-graft cultured pearls generally contain domains of calcite, emitting orange Mn{sup 2+}-activated CL which are almost absent in the natural freshwater pearls from the Mississippi river. Freshwater pearls showing much higher Mn concentrations build in calcitic and aragonitic parts compared to saltwater pearls.

Habermann, D. E-mail: dirk.habermann@physik.tu-freiberg.de; Banerjee, A.; Meijer, J.; Stephan, A

2001-07-01

 
 
 
 
261

Investigation of manganese in salt- and freshwater pearls  

International Nuclear Information System (INIS)

The trace element distribution in natural and cultured pearls is analysed by micro-PIXE, cathodoluminescence (CL) microscopy and spectroscopy and electron spin resonance (ESR) spectroscopy to develop a new method to distinguish cultured from natural pearls. These different kinds of pearls can be identified by their manganese content and its distribution in aragonite and calcite structure, respectively. Manganese content of natural freshwater pearls from Persian Gulf was compared to that of natural freshwater pearls from the Mississippi river (USA). Moreover manganese content of tissue-graft freshwater pearls from Chansu (China) was compared to that of natural freshwater pearls from the Mississippi river (USA). It was proved that the Chinese freshwater tissue-graft cultured pearls generally contain domains of calcite, emitting orange Mn2+-activated CL which are almost absent in the natural freshwater pearls from the Mississippi river. Freshwater pearls showing much higher Mn concentrations build in calcitic and aragonitic parts compared to saltwater pearls.

2001-01-01

262

REVIEW OF FRESHWATER BIOASSAY PROCEDURES FOR SELECTED AMPHIPODS  

Science.gov (United States)

Methods previously used for performing gammarid bioassays and several important life-cycle requirements are reviewed. The discussion is largely based on methodology for the amphipods Gammarus fasciatus, Gammarus lacustris, and Gammarus pseudolimnaeus, but additional evidence, gat...

263

Floodplain data: ecosystem characteristics and 137Cs concentrations in biota and soil  

International Nuclear Information System (INIS)

Radiocesium (137Cs) distribution was determined in soil, roots, ground vegetation, overstory, litter, mammals, feces, and insects for a floodplain ecosystem contaminated by radioactive wastes from Manhattan Project operations in 1944. The 2-ha research site was located on the ERDA reservation, Oak Ridge, Tennessee, in a drained holding pond between Oak Ridge National Laboratory and White Oak Lake. Maximum 137Cs concentrations in soil occurred near the old retention pond dam (84,400 pCi/g) and at the upper portion of the floodplain boundary (70,500 pCi/g). This bimodal distribution pattern of 137Cs was evident for all samples collected. Large amounts of data have been collected since the summer of 1974. This report documents the data on ecosystem characteristics and 137Cs concentrations in biota and soil

1976-01-01

264

Studies on monitoring of river water quality by neutron activation analysis of aquatic biota  

International Nuclear Information System (INIS)

In order to clarify the possibility of a new method to monitor the river water quality by neutron activation analysis of aquatic biota, the followings were investigated: (1) the species of fish, water plants and aquatic insects which we can collect easily in Tamagawa River basin, (2) problems in pre-treatment of biological samples, and (3) relationship between elemental concentrations in biological samples and in river water. We found that the biological species suitable for the analytical investigation are Carassius auratus langsdorfii (GINBUNA), Pseudorasbora parva (MOTSUGO), Potamageton orientalis Hagst. (AINOKOITOMO), Elodea nuttalli (Planch.) St. John (KOKANADAMO), Cheuma-topsyche brevilineata (Iwata) (KOGATASHIMATOBIKERA) and Hydropsyche orientalis Martynov (URUMASHIMATOBIKERA). Fish samples showed apparently different concentrations of elements in each part of their bodies. Simple washing of water plants and aquatic insects was found not to be enough to eliminate rock-oriented particles. Such elements as Ag, Mn and Zn showed relationships of their concentrations between in biological samples and in river water. (author).

1990-01-01

265

Dynamic model for the assessment of radiological exposure to marine biota  

International Nuclear Information System (INIS)

A generic approach has been developed to simulate dynamically the uptake and turnover of radionuclides by marine biota. The approach incorporates a three-compartment biokinetic model based on first order linear kinetics, with interchange rates between the organism and its surrounding environment. Model rate constants are deduced as a function of known parameters: biological half-lives of elimination, concentration factors and a sample point of the retention curve, allowing for the representation of multi-component release. The new methodology has been tested and validated in respect of non-dynamic assessment models developed for regulatory purposes. The approach has also been successfully tested against research dynamic models developed to represent the uptake of technetium and radioiodine by lobsters and winkles. Assessments conducted on two realistic test scenarios demonstrated the importance of simulating time-dependency for ecosystems in which environmental levels of radionuclides are not in equilibrium.

2008-01-01

266

Bioaccumulation of artificial radionuclides and dose assessment to biota in the Yenisei River (Russia)  

International Nuclear Information System (INIS)

The subject of this paper is reconstruction of accumulation of artificial radionuclides (32P, 137Cs, 65Zn, 51Cr, 54Mn) by the Yenisei River biota during the 25-years period (1975-2000), and estimation of the internal dose rates to the river organisms. Yenisei River is located in Central Siberia (Russia); since 1958 artificial radionuclides intake to the Yenisei River with the routine releases from the Krasnoyarsk Mining and Chemical Industrial Complex (KMCIC). Among the radionuclides presented in the releases, 32P is of particular importance. Reconstruction of the radionuclide assimilation by the Yenisei biota was performed using the ECOMOD model approach. The model considers a radionuclide as a tracer, identical in its properties to a stable (analogous) element participated in the metabolism of aquatic organism. Radionuclide assimilated by an organism goes to the production of new biomass, and to compensation of metabolic losses of the analogous bioelement. Basic equations of the general ECOMOD approach are described in the paper. The model was adapted to the conditions of the Yenisei River and applied to calculate the dynamics of 32P, 137Cs, 65Zn, 51Cr, 54Mn in the most typical Yenisei fish species: roach (non-predatory) and pike (predatory). Shown are the reconstructed activity concentrations in roach and pike at the distances 16-80 km downstream the KMCIC. Activity concentrations of 32P in the Yenisei fish were considerably higher comparing with other radionuclides. Activity concentrations of 32P, 65Zn, 51Cr, 54Mn in roach are higher than in pike, whereas activity concentrations of 137Cs are higher in predatory species. Results of the model reconstruction were compared with the available data of measurements, and such comparison confirms adequacy of the model predictions. Long-term dynamics of the internal exposure was estimated for the river organisms at the distances 16-80 km downstream the KMCIC. Average dose rates from incorporated ?-emitters were calculated taking into account geometric characteristics of organisms; ?- particles were assumed to be totally absorbed within the organisms. Average length of roach in the Yenisei River is 0.2 m, weight 0.17 kg; average length of pike in the Yenisei River is 0.52 m, weight 1.2 kg. Dose conversion factors for 32P, 137Cs, 65Zn, 51Cr and 54Mn are shown in Table 3. Annual average dose rates from incorporated radionuclides to the Yenisei biota are presented. Maximum dose rates occurred in 1975-1980 and varied from 11 mGy/year (predatory fish) to 63 mGy/year (molluscs). These levels were several times higher than the background exposure to the Yenisei organisms, which was estimated as 0.7-4 mGy/year. Major contributor to the internal exposure to the Yenisei biota is 32P (up to 95%)

2004-01-01

267

A kinetic-allometric approach to predicting tissue radionuclide concentrations for biota  

International Nuclear Information System (INIS)

Allometry, or the biology of scaling, is the study of size and its consequences. It has become a useful tool for comparative physiology. There are several allometric equations that relate body size to many parameters, including ingestion rate, lifespan, inhalation rate, home range and more. While these equations were originally derived from empirical observations, there is a growing body of evidence that these relationships have their origins in the dynamics of energy transport mechanisms. As part of an ongoing effort by the Department of Energy in developing generic methods for evaluating radiation dose to biota, we have examined the utility of applying allometric techniques to predicting radionuclide tissue concentration across a large range of terrestrial and riparian species of animals. This particular study examined 23 radionuclides. Initial investigations suggest that the allometric approach can provide a useful tool to derive limiting values of uptake and elimination factors for animals.

2003-01-01

268

Fruit and seed floras from exceptionally preserved biotas in the European Paleogene  

Directory of Open Access Journals (Sweden)

Full Text Available Fossil fruit and seed assemblages from two exceptionally preserved biotas provide considerable information about systematics, diversity, dispersal biology and plant animal interactions in the European Paleogene. The first is from the Middle Eocene Messel oil shale in the Messel Pit near Darmstadt, Germany and occurs in association with exceptionally preserved flowers, insects and vertebrates. The second is from the latest Eocene Insect Limestone (Bembridge Marls Member, Solent Group) from the northern coast of the Isle of Wight, UK and occurs in association with exceptionally preserved insects. These two assemblages of compressed fruits and seeds both preserve delicate structures including plumes, wings and a fruit with a long awn. The Messel site also has rare, completely preserved fruiting heads and other specimens with organic connections, preservation of soft tissues, and seeds found within animal gut contents. The Messel flora is especially important for understanding Middle Eocene dispersal biology, biogeography and floristic diversity.

Collinson M; Manchester S R; Wilde V; Hayes P

2010-01-01

269

Taiwan's industrial heavy metal pollution threatens terrestrial biota  

Energy Technology Data Exchange (ETDEWEB)

The bioconcentration levels of essential (Cu, Fe, Mg, Mn, and Zn) and non-essential (As, Cd, Hg, Pb, and Sn) elements have been investigated in different terrestrial biota such as fungi, plant, earthworm, snail, crab, insect, amphibian, lizard, snake, and bat including the associated soil, to investigate the ecosystem health status in Kenting National Park, Taiwan. High bioconcentrations of Cd, Hg, and Sn in snail, earthworm, crab, lizard, snake, and bat indicated a contaminated terrestrial ecosystem. High concentrations of Cd, Hg, and Sn in plant species, effective bioaccumulation of Cd by earthworm, snail, crab and bat, as well as very high levels of Hg found in invertebrates, amphibians, and reptiles revealed a strong influence from industrial pollution on the biotic community. This study for the first time presents data on the impact of heavy metal pollution on various terrestrial organisms in Taiwan. - Metal effects occur at any terrestrial levels in Taiwan.

Hsu, M.J. [Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China); Selvaraj, K. [Institute of Marine Geology and Chemistry, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China); Agoramoorthy, G. [Department of Pharmacy, Tajen University, Yanpu, Pingtung 907, Taiwan (China)]. E-mail: agoram@mail.tajen.edu.tw

2006-09-15

270

Positive relationship between herbaceous layer diversity and the performance of soil biota in a temperate forest  

UK PubMed Central (United Kingdom)

The current decline in biodiversity is particularly pronounced in the herbaceous layer of forest ecosystems. We explored the relationship between a naturally occurring plant diversity gradient in the understory vegetation of a deciduous forest and several above-and belowground ecosystem processes. We show that particularly soil microbial parameters and microarthropod densities are positively correlated with plant species richness. These results confirm recent findings in grassland ecosystems and highlight the intimate interconnectance between the diversity and functioning of above-and belowground compartments. We conclude that irrespective of a potential causal relationship between plant species richness and belowground processes, it is essential to consider the performance of soil biota in order to understand the relationship between herbaceous layer composition and ecosystem function.

Eisenhauer Nico; Yee Karen; Johnson EdwardA; Maraun Mark; Parkinson Dennis; Straube Daniela; Scheu Stefan

2011-02-01

271

The Pipe Creek Sinkhole biota, a diverse late tertiary continental fossil assemblage from Grant County, Indiana  

Science.gov (United States)

Quarrying in east-central Indiana has uncovered richly fossiliferous unconsolidated sediment buried beneath Pleistocene glacial till. The fossiliferous layer is part of a sedimentary deposit that accumulated in a sinkhole developed in the limestone flank beds of a Paleozoic reef. Plant and animal (mostly vertebrate) remains are abundant in the fossil assemblage. Plants are represented by a diversity of terrestrial and wetland forms, all of extant species. The vertebrate assemblage (here designated the Pipe Creek Sinkhole local fauna) is dominated by frogs and pond turtles, but fishes, birds; snakes and small and large mammals are also present; both extinct and extant taxa are represented. The mammalian assemblage indicates an early Pliocene age (latest Hemphillian or earliest Blancan North American Land Mammal Age). This is the first Tertiary continental biota discovered in the interior of the eastern half of North America.

Farlow, J. O.; Sunderman, J. A.; Havens, J. J.; Swinehart, A. L.; Holman, J. A.; Richards, R. L.; Miller, N. G.; Martin, R. A.; Hunt, Jr. , R. M.; Storrs, G. W.; Curry, B. B.; Fluegeman, R. H.; Dawson, M.; Flint, M. E. T.

2001-01-01

272

Is marine debris ingestion still a problem for the coastal marine biota of southern Brazil?  

Science.gov (United States)

The accumulation of synthetic debris in marine and coastal environments is a consequence of the intensive and continuous release of these highly persistent materials. This study investigates the current status of marine debris ingestion by sea turtles and seabirds found along the southern Brazilian coast. All green turtles (n=34) and 40% of the seabirds (14 of 35) were found to have ingested debris. No correlation was found between the number of ingested items and turtle's size or weight. Most items were found in the intestine. Plastic was the main ingested material. Twelve Procellariiformes (66%), two Sphenisciformes (22%), but none of the eight Charadriiformes were found to be contaminated. Procellariiformes ingested the majority of items. Plastic was also the main ingested material. The ingestion of debris by turtles is probably an increasing problem on southern Brazilian coast. Seabirds feeding by diverse methods are contaminated, highlighting plastic hazard to these biota. PMID:19931101

Tourinho, Paula S; Ivar do Sul, Juliana A; Fillmann, Gilberto

2010-03-01

273

Is marine debris ingestion still a problem for the coastal marine biota of southern Brazil?  

UK PubMed Central (United Kingdom)

The accumulation of synthetic debris in marine and coastal environments is a consequence of the intensive and continuous release of these highly persistent materials. This study investigates the current status of marine debris ingestion by sea turtles and seabirds found along the southern Brazilian coast. All green turtles (n=34) and 40% of the seabirds (14 of 35) were found to have ingested debris. No correlation was found between the number of ingested items and turtle's size or weight. Most items were found in the intestine. Plastic was the main ingested material. Twelve Procellariiformes (66%), two Sphenisciformes (22%), but none of the eight Charadriiformes were found to be contaminated. Procellariiformes ingested the majority of items. Plastic was also the main ingested material. The ingestion of debris by turtles is probably an increasing problem on southern Brazilian coast. Seabirds feeding by diverse methods are contaminated, highlighting plastic hazard to these biota.

Tourinho PS; Ivar do Sul JA; Fillmann G

2010-03-01

274

Group report: Physiological and ecological effects of acidification on aquatic biota (Chapter 19). Book chapter  

Energy Technology Data Exchange (ETDEWEB)

Acidification affects all components of biological communities in lakes and streams: microbes, algae, macrophytes, invertebrates, fish amphibians, and other vertebrates that rely on aquatic ecosystems for habitat or food. Mechanisms of effect are both direct (toxic responses to changes in chemistry) and indirect (e.g., expressed through the food chain or caused by changes in habitat), and the responses may be immediate or delayed. In turn, many biological processes, especially microbial processes, can influence surface water acid-base chemistry. Thus, chemical and biological changes are intricately linked and complex, with extensive feedbacks. Research on the effects of acid deposition and acidification on aquatic biota has been ongoing in Europe and North America for over the last 15 years, and many comprehensive reviews have been published. These gaps often have occurred because funding has focused on chemical mechanisms and modeling response of systems rather than in making resource inventories or resolving uncertainties in biological responses to acidification.

Baker, J.P.; Boehmer, J.; Hartmann, A.; Havas, M.; Jenkins, A.

1994-01-01

275

Metal contamination in water, sediment and biota from a semi-enclosed coastal area.  

UK PubMed Central (United Kingdom)

This study identifies and quantifies the spatial variations of metal contamination in water, sediment and biota: the common cockle (Cerastoderma edule) and the Mermaid's glove sponge (Haliclona oculata), within a heavily anthropogenically impacted semi-enclosed estuarine-coastal area with a low ability to disperse and flush contaminants (Poole Harbour, UK). The results showed that metal contamination was detected in all environmental compartments. Water was polluted with As, and Hg sediment metals were mostly within "the possible effect range" in which adverse effects occasionally occurs. Cockles had considerable concentrations of Ni, Ag and Hg in areas close to pollution sources, and sponges accumulate Cu and Zn with very high magnitude. A systematic monitoring approach that includes biological monitoring techniques, which covers all embayments, is needed, and an integrated management of the semi-enclosed coastal zones should be based on the overall hydrological characteristics of these sensitive areas and their ability to self-restore which is different than open coastal zones.

Aly W; Williams ID; Hudson MD

2013-05-01

276

Dependency of soil activity concentration on soil -biota concentration ratio of radionuclides for earthworm  

International Nuclear Information System (INIS)

The transfer of radionuclides to wildlife (non-human biota) is normally quantified using an equilibrium concentration ratio (CReq), defined as the radionuclide activity concentration in the whole organism (fresh weight) divided by that in the media (dry weight for soil). The present study describes the effect of soil radionuclide activity concentration on the transfer of 137Cs, 85Sr and 65Zn to a functionally important wildlife group, annelids, using a commonly studied experimental worm (E.andrei). Time-dependent whole body concentration ratios of 137Cs, 85Sr and 65Zn for the earthworm were experimentally measured for artificially contaminated soils with three different activity concentrations for each radionuclide which were considerably higher than normal background levels. Two parameters of a first order kinetic model, the equilibrium concentration ratio (CReq) and the effective loss rate constant (k), were estimated by comparison of experimental CR results with the model prediction

2012-01-01

277

Calorific and carbon values of marine and freshwater Protozoa  

Science.gov (United States)

Calorific and carbon values were determined for a variety of marine and freshwater Protozoa ( Noctiluca miliaris, Euplotes sp., Eufolliculina sp. respectively Tetrahymena pyriformis, Paramecium caudatum), their food sources (Bacteria, Dunaliella primolecta, Ceratium hirundinella), and for Protozoa-dominated plankton samples. Most calorific values lie close to the centre of the range covering organisms in general. Low values in some marine samples probably resulted from the retention of bound water in the dried material. When all results were combined with data selected from the literature, the dependence of calorific value on carbon content was highly significant. This relationship is probably also adequately described by an energy-carbon regression through the variety of organic compounds commonly found in organisms. Calorific value expressed per unit carbon is shown to vary little in Protozoa (mean conversion factor 46 J [mg C]-1) or throughout the range of biological materials considered in this study (45 J [mg C]-1).

Finlay, B. J.; Uhlig, G.

1981-12-01

278

Study of the uncertainty in estimation of the exposure of non-human biota to ionising radiation  

International Nuclear Information System (INIS)

Uncertainty in estimations of the exposure of non-human biota to ionising radiation may arise from a number of sources including values of the model parameters, empirical data, measurement errors and biases in the sampling. The significance of the overall uncertainty of an exposure assessment will depend on how the estimated dose compares with reference doses used for risk characterisation. In this paper, we present the results of a study of the uncertainty in estimation of the exposure of non-human biota using some of the models and parameters recommended in the FASSET methodology. The study was carried out for semi-natural terrestrial, agricultural and marine ecosystems, and for four radionuclides (137Cs, 239Pu, 129I and 237Np). The parameters of the radionuclide transfer models showed the highest sensitivity and contributed the most to the uncertainty in the predictions of doses to biota. The most important ones were related to the bioavailability and mobility of radionuclides in the environment, for example soil-to-plant transfer factors, the bioaccumulation factors for marine biota and the gut uptake fraction for terrestrial mammals. In contrast, the dose conversion coefficients showed low sensitivity and contributed little to the overall uncertainty. Radiobiological effectiveness contributed to the overall uncertainty of the dose estimations for alpha emitters although to a lesser degree than a number of transfer model parameters.

2004-12-01

279

A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid  

Directory of Open Access Journals (Sweden)

Full Text Available Freshwater habitats and species living in freshwater are generally more prone to extinction than terrestrial or marine ones. Immediate conservation measures for world-wide freshwater resources are thus of eminent importance. This is particularly true for so called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact. Lake Ohrid, the European biodiversity hotspot, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes. Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1) assess threats to Lake Ohrids' (endemic) biodiversity, (2) summarize existing conservation activities and strategies, and (3) outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species) as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1) watershed impacts, (2) agriculture and forestry, (3) tourism and population growth, (4) non-indigenous species, (5) habitat alteration or loss, (6) unsustainable exploitation of fisheries, and (7) global climate change. Of the 11 IUCN (International Union for Conservation of Nature and Natural Resources) threat classes scored, seven have moderate and three severe impacts. These latter threat classes are energy production and mining, biological resource use, and pollution. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species measures, international conservation activities, and ongoing research on conservation and raising of public awareness. Following this summary, we evaluate the status quo and future of Lake Ohrid and its biota. Given the number of identified threats, it is clear that only concerted international action can stop or at least slow down further degradation of Lake Ohrid and the creeping biodiversity crisis already evident. A comprehensive conservation strategy should include measures that result in an immediate reduction of pollution, particularly with phosphorous, in order to slow down the ongoing eutrophication process. The existing watershed management should become more effective. Implementation and particularly with a view to the enforcement of national laws should be enhanced. Increased research on the lakes' limnology, biodiversity, and conservation management practices are necessary. The latter research should identify conservation priorities. Public awareness should be enhanced. Facing these parallel needs to protect the unique biodiversity of Lake Ohrid, we suggest urging (a) implementation and enforcement of the General Management Plan that would ensure long-term integrated and sustainable use of the lake and its watershed, (b) scientific studies on ecology, biodiversity and effects of human impact, (c) the establishment of Core Conservation areas (CCA), including underwater reserves, and (d) Coastal Zone Management (CZM) areas that would constitute buffer zones for the CCA around the lake. These activities should, among others, ultimately lead to a trans-boundary major conservation area of the Ohrid-Prespa region that would allow long-term integration of both humans and nature.

G. Kostoski; C. Albrecht; S. Trajanovski; T. Wilke

2010-01-01

280

TENORM wastes and the potential alpha radiation dose to aquatic biota  

International Nuclear Information System (INIS)

In the years seventies release-rates and derived limits for releasing radionuclides into the environment were adopted for each particular radionuclide and for a number of pathways. The release-rate limit adopted for alpha emitters was 1015 Bq.y-1 for a single site, but limited to 1014 Bq.y-1 for 226Ra and supported 210Po. In addition, to meet the requirements of the London Convention, a derived limit should be expressed in terms of concentration, which for alpha emitters was 1010 Bq.t-1 , but limited to 1014 Bq.t-1 for 226Ra and supported 210Po, assuming an upper limit to the mass dumping rate of 105 t per year at a single dumping site. New data on the radioactivity in the marine environment and biota, including plankton, indicated a potential alpha radiation dose to these aquatic organisms due to the release of technologically enhanced naturally occurring radioactive materials (TENORM) wastes. At the highest accumulation of 239Pu in the zooplankton Gammarus in Thule, Greenland, due to an accidental release associated with military activities, the dose rate reached about 0.14 ?Gy.h-1 . Such dose rate was similar to that received by the phytoplankton Chaetoceros and Rhizosolenia from Agulhas current, Africa, due to naturally occurring radioactive materials (NORpposedly enhanced for almost one century of gold mining at first, and subsequently because of heap-leaching uranium extraction from the tailings left behind by earlier gold miners. The paper will discuss the alpha radiation dose to aquatic biota, in general, and to plankton, in particular, due to potential releases of TENORM wastes in the aquatic environment. (author)

2002-01-01

 
 
 
 
281

Organophosphorus flame retardants and plasticizers in marine and fresh water biota and in human milk.  

UK PubMed Central (United Kingdom)

The levels and relative proportions of 11 organophosphorus flame retardants and plasticizers (OPs), some of which are reportedly toxic to aquatic organisms, were investigated in human breast milk and samples of fish and mussels from Swedish lakes and coastal areas in order to assess spatial differences in environmental exposure and spatial and temporal differences in human exposure. Some of the biota samples were collected at locations with known potential sources of OPs, but most were collected in background locations. Tris-2-chloroisopropyl phosphate (TCPP) and triphenyl phosphate (TPP) dominated in the biota with levels ranging from 170 to 770 ng g(-1) for TCPP in perch and between 21 and 180 ng g(-1) for TPP. In milk samples, TCPP (median 45 ng g(-1)) and tributyl phosphate (median 12 ng g(-1)) were the most frequently occurring OPs. Among samples of fish from background locations, the concentrations and profiles of most OPs were quite similar, indicating that their sources were diffuse. However, in fish from sample locations near known sources, there were marked differences in OP concentrations and profiles. Fish from a stream receiving surface water from Arlanda airport displayed high levels of OPs (10 200 ng g(-1)) that are commonly used in aircraft hydraulic fluids. Fish collected at points 1 or 2 km downstream of sewage treatment plants showed significantly higher levels of tris(2-butoxyethyl) phosphate (TBEP), one of the most typically abundant OP in effluents from such plants. In the milk samples obtained from women in different towns no distinct differences were detected in OP concentrations or profiles. However, the levels of TBEP tended to be higher in milk collected 10 years ago than in milk collected more recently. However, human exposure to OPs through eating fish or to breastfeeding babies seems to be of minor importance in relation to other potential sources, such as indoor dust inhalation and ingestion.

Sundkvist AM; Olofsson U; Haglund P

2010-04-01

282

CROATIAN FRESHWATER FISHERY IN 2001 and 2002  

Directory of Open Access Journals (Sweden)

Full Text Available For each segment of freshwater fisheries — freshwater aquaculture, commercial and sport and recreational fisheries — there is a legal obligation for data submission to the Ministry of agriculture and forestry, Directorate of fisheries. Within the segments of commercial and sport and recreational fisheries the data submission obligation refers to the period beginning with the year 2003, while in the segment of aquaculture that obligation includes also the year 2002. Data collected for freshwater aquaculture contain the information on production of freshwater fish, total production areas, food, fertilizers and subsidies for freshwater fish farming. Data collected for commercial and sport and recreational fisheries contain the information on catch quantities and number of commercial and sport and recreational fishermen. Freshwater fish production in the year 2001 was 5,549. 50 tons, while the total fresh water fish production in the year 2002 decreased for 1.00% compared to the previous year, amounting to 5,501.07 tons. Although total fresh water fish production constantly decreases comparing to previous years, trout production has increased and the maximum production was noted in the year 2002. Total area of the freshwater fish farms in the year 2001 increased compared to the year 2000 for 2.14% amounting to 11,880.41 ha. Actual production area slightly increased in comparison to the previous year as well and amounted to 9,214.11 ha. In the year 2002 total area of freshwater fish farms was 11,491.29 ha, and 72.13% of that figure was the actual production area, that is 8,288.27 ha. Production per unit area in the year 2001 was 485.31 kg/ha for warm–water species and 280.44 t/ha for cold–water species. In the year 2002 production per unit area for warm–water species was 462.95 kg/ha, and for cold–water species 315.26 t/ha. During the year 2001, in total, 10,575.82 t of food was spent and 1,891 tons of fertilizers and lime, while in the year 2002 12,195.40 tons of food and 2,104 tons of fertilizers and lime. Regarding the number of commercial fishermen the decrease was noted for the period of 2001–2002 in comparison with the period 1998–2000. The total number of sport and recreational fisheren in the year 2001 was 57,781 and in the year 2002 their number was 56,210. During the years 2001 and 2002 subsidies for 8 freshwater species were issued amounting as follows: for carp, grass carp, bighead carp and silver carp the subsidies were 4.00 kn/kg, and for tench, trout, pikeperch, catfish and pike the amount was 6.00 kn/kg.

Irena Jahutka; Zlatko Homen

2003-01-01

283

Baseline levels and trophic transfer of persistent organic pollutants in sediments and biota from the Congo River Basin (DR Congo).  

Science.gov (United States)

The present study aimed to evaluate the occurrence of persistent organic pollutants (POPs: (PCBs, PBDEs, DDTs, HCHs, CHLs and HCB) in sediments and biota from the middle Congo River Basin (CRB) and to investigate their trophic transfer through the aquatic food web using nitrogen stable isotope ratios. To our knowledge, no data on levels of POPs in sediment and biota from the CRB are present in the literature, and studies on trophic transfer and biomagnification profiles of POPs using ?(15)N are scarce in tropical regions. POP levels in the sediment and biota were low, with exception of total PCB levels found in fish from the Itimbiri River (1.4 to 44ng/g ww). Compared to concentrations found in fish from pristine to relatively industrial developed areas, the ?PCB levels in fish from the Itimbiri were high, indicating the presence of a local PCB contamination source in this catchment. Based on minimum risk level criteria formulated by ATSDR, the consumption of PCB contaminated fish from the Itimbiri river poses a potential risk for humans. The POP levels in biota were not significantly related to the POP levels in sediments, and the BSAF concept (Biota-Sediment Accumulation Factor) was found to be a poor predictor of the bioavailability and bioaccumulation of environmental pollutants in the present study. With increasing trophic levels, a significant increase in PCB 95, 101, 110, 138, 146, 149, 153, 174, 180 & 187 and p,p'-DDT in Itimbiri and BDE 47 & 99 in Itimbiri, Aruwimi & Lomami river basins was observed. Trophic magnification factors were higher than 1, indicating that biomagnification occurs through the tropical food web. PMID:23872388

Verhaert, Vera; Covaci, Adrian; Bouillon, Steven; Abrantes, Katya; Musibono, Dieudonné; Bervoets, Lieven; Verheyen, Erik; Blust, Ronny

2013-07-17

284

Baseline levels and trophic transfer of persistent organic pollutants in sediments and biota from the Congo River Basin (DR Congo).  

UK PubMed Central (United Kingdom)

The present study aimed to evaluate the occurrence of persistent organic pollutants (POPs: (PCBs, PBDEs, DDTs, HCHs, CHLs and HCB) in sediments and biota from the middle Congo River Basin (CRB) and to investigate their trophic transfer through the aquatic food web using nitrogen stable isotope ratios. To our knowledge, no data on levels of POPs in sediment and biota from the CRB are present in the literature, and studies on trophic transfer and biomagnification profiles of POPs using ?(15)N are scarce in tropical regions. POP levels in the sediment and biota were low, with exception of total PCB levels found in fish from the Itimbiri River (1.4 to 44ng/g ww). Compared to concentrations found in fish from pristine to relatively industrial developed areas, the ?PCB levels in fish from the Itimbiri were high, indicating the presence of a local PCB contamination source in this catchment. Based on minimum risk level criteria formulated by ATSDR, the consumption of PCB contaminated fish from the Itimbiri river poses a potential risk for humans. The POP levels in biota were not significantly related to the POP levels in sediments, and the BSAF concept (Biota-Sediment Accumulation Factor) was found to be a poor predictor of the bioavailability and bioaccumulation of environmental pollutants in the present study. With increasing trophic levels, a significant increase in PCB 95, 101, 110, 138, 146, 149, 153, 174, 180 & 187 and p,p'-DDT in Itimbiri and BDE 47 & 99 in Itimbiri, Aruwimi & Lomami river basins was observed. Trophic magnification factors were higher than 1, indicating that biomagnification occurs through the tropical food web.

Verhaert V; Covaci A; Bouillon S; Abrantes K; Musibono D; Bervoets L; Verheyen E; Blust R

2013-09-01

285

The use of multiple tracers for tracking wastewater discharges in freshwater systems.  

UK PubMed Central (United Kingdom)

The assessment of potential impacts of wastewater effluent discharges in freshwater systems requires an understanding of the likely degrees of dilution and potential zones of influence. In this study, four tracers commonly present in wastewater effluents were monitored to compare their relative effectiveness in determining areas in freshwater systems that are likely to be impacted by effluent discharges. The four tracers selected were the human pharmaceutical carbamazepine, anthropogenic gadolinium, fluorescent-dissolved organic matter (fDOM), and electrical conductivity (EC). The four tracers were monitored longitudinally in two distinct freshwater systems receiving wastewater effluents, where one site had a high level of effluent dilution (effluent <1 % of total flow) and the other site had a low level of effluent dilution (effluent ?50 % of total flow). At both sites, the selected tracers exhibited a similar pattern of response intensity downstream of discharge points relative to undiluted wastewater effluent, although a number of anomalies were noted between the tracers. Both EC and fDOM are non-specific to human influences, and both had a high background response, relative to the highly sensitive carbamazepine and anthropogenic gadolinium responses, although the ease of measuring EC and fDOM would make them more adaptable in highly variable systems. However, the greater sensitivity and selectivity of carbamazepine and gadolinium would make their combination with EC and fDOM as tracers of wastewater effluent discharges highly desirable to overcome potential limitations of individual tracers.

Williams M; Kumar A; Ort C; Lawrence MG; Hambly A; Khan SJ; Kookana R

2013-06-01

286

Physical processes in freshwater ecosystems  

International Nuclear Information System (INIS)

[en] In the present paper the main methodological approaches to model the physical processes controlling the migration of radionuclides through water ecosystems are presented and discussed. These processes include the dispersion and the transport through the water and the migration from and to the bottom sediments caused by the settling and the re-suspension of contaminated particles of suspended matter. The equations that control the above processes and that are used by most existing state-of-the-art models are listed and briefly discussed and motivated. Values of the parameters in the equations have been selected following a review of information available from the scientific literature. (author)

2009-01-01

287

Luminescence properties of a nanoporous freshwater diatom.  

UK PubMed Central (United Kingdom)

Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an ?-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay.

Goswami B; Choudhury A; Buragohain AK

2012-01-01

288

SOME FRESHWATER SNAILS FROM NORTHERN IRAN  

Directory of Open Access Journals (Sweden)

Full Text Available There are many freshwater snails involved in the life cycle of parasitic flukes. Some of these animals, such as Bulinus spp and Lymnaea spp are very important in public health and veterinary medicine. For example, Bulinus trucatus and Lymnaeid snails transmit Human Bilharziosis and zoonotic Fascioliosis, respectively. For this reason most freshwater bodies of northern Iran, were searched for potential intermediate host snails of medical parasites. Thirteen mollusc taxa, i.e. 5 operculated shell-bearing versus 8 pulmonated snails were found during a snail survey, in the summer of 1992. Two taxa, viz. Anisus leucostoma and Bulinus truncatus were found to be new species for Iran and northern Iran, respectively.

A. Mansoorian

2000-01-01

289

Assessing the freshwater distribution of yellow eel  

Directory of Open Access Journals (Sweden)

Full Text Available In the global context of the decline in wild species, modeling the distribution of populations is a crucial aspect of ecological management. This can be a major challenge, especially for species, such as the European eel, that have complex life cycles, exhibit cryptic behavior, or migrate over long distances. A review of the literature suggests that eel size data could be used to assess and analyze freshwater distribution of eel. We argue that analyses based on small yellow eels (? 300 mm) along the longitudinal course of rivers could provide a valuable tool for population monitoring. We propose a standardized catchment recruitment index and a colonization index based on the probability of occurrence (presence/absence data) using logistic models for different size classes. The model developed here provides a convenient guide for assessing yellow eel stages in freshwater areas, and should have concrete applications for management of the species.

É. Lasne; Laffaille

2008-01-01

290

Freshwater fishes of Tsitsikamma National Park  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to determine the distribution and relative abundance of freshwater fishes in the Tsitsikamma National Park. Fish assemblages in six river systems were sampled in 2001, with a total of 323 fish from eight species recorded. Indigenous fish collected included four freshwater species (Pseudobarbus afer, Pseudobarbus tenuis, Sandelia capensis, Anguilla mossambica), three estuarine species (Monodactylus falciformis, Caffrogobius gilchristi, Myxus capensis), and one alien (Micropterus salmoides). One additional indigenous species (Galaxias zebratus) and two aliens (Salmo trutta, Oncorhynchus mykiss) could potentially occur within the park. The topography and locality of the park presents a unique opportunity to meaningfully conserve the endangered P. tenuis as well as other fish characteristic of the eastern reaches of the Cape Floristic Region. Management action is required to minimise opportunities for further establishment and spread of alien fish species and to conserve indigenous fish assemblages within the park.

I.A. Russell

2002-01-01

291

Freshwater fishes of Bontebok National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Fish assemblages were sampled at six sites in the Breede River in the Bontebok National Park during 1999 and 2000. A total of 380 fish from 12 species was recorded. Indigenous fish collected included one freshwater species (Barbus andrewi), two catodromous species (Anguilla mossambica, Myxus capensis). and three estuarine species (Gilchris- tella aestuaria, Monodactylusfalciformis, Mugil cephalus). Four of the species recorded were aliens (Tinea tinea, Lepomis macrochirus, Micropterus salmoides, Micropterus dolomieu) and two species translocated from other South African rivers (Tilapia sparrmanii, Clarias gariepinus). A further two indigenous species (Sandelia capensis, Pseudobarbus biirchelli) could potentially occur within the park, though the high abundance of alien predators means that there is little chance for recolonisation from tributaries higher in the Breede River system. There is little opportunity to meaningfully conserve most indigenous freshwater fish in Bontebok National Park.

I.A. Russell

2001-01-01

292

Extraction of Freshwater and Energy from Atmosphere  

CERN Multimedia

Author offers and researches a new, cheap method for the extraction of freshwater from the Earth atmosphere. The suggected method is fundamentally dictinct from all existing methods that extract freshwater from air. All other industrial methods extract water from a saline water source (in most cases from seawater). This new method may be used at any point in the Earth except Polar Zones. It does not require long-distance freshwater transportation. If seawater is not utilized for increasing its productivity, this inexpensive new method is very environment-friendly. The author method has two working versions: (1) the first variant the warm (hot) atmospheric air is lifted by the inflatable tube in a high altitude and atmospheric steam is condenced into freswater: (2) in the second version, the warm air is pumped 20-30 meters under the sea-surface. In the first version, wind and solar heating of air are used for causing air flow. In version (2) wind and propeller are used for causing air movment. The first method...

Bolonkin, Alexander

2007-01-01

293

Clonal diversity driven by parasitism in a freshwater snail.  

Science.gov (United States)

One explanation for the widespread abundance of sexual reproduction is the advantage that genetically diverse sexual lineages have under strong pressure from virulent coevolving parasites. Such parasites are believed to track common asexual host genotypes, resulting in negative frequency-dependent selection that counterbalances the population growth-rate advantage of asexuals in comparison with sexuals. In the face of genetically diverse asexual lineages, this advantage of sexual reproduction might be eroded, and instead sexual populations would be replaced by diverse assemblages of clonal lineages. We investigated whether parasite-mediated selection promotes clonal diversity in 22 natural populations of the freshwater snail Melanoides tuberculata. We found that infection prevalence explains the observed variation in the clonal diversity of M. tuberculata populations, whereas no such relationship was found between infection prevalence and male frequency. Clonal diversity and male frequency were independent of snail population density. Incorporating ecological factors such as presence/absence of fish, habitat geography and habitat type did not improve the predictive power of regression models. Approximately 11% of the clonal snail genotypes were shared among 2-4 populations, creating a web of 17 interconnected populations. Taken together, our study suggests that parasite-mediated selection coupled with host dispersal ecology promotes clonal diversity. This, in return, may erode the advantage of sexual reproduction in M. tuberculata populations. PMID:24118641

Dagan, Y; Liljeroos, K; Jokela, J; Ben-Ami, F

2013-10-01

294

A new tropical algal test to assess the toxicity of metals in freshwaters. Supervising Scientists Report 133  

International Nuclear Information System (INIS)

Copper (Cu) and uranium (U) are of potential ecotoxicological concern to tropical Australian freshwater biota as a result of mining impacts. No local data on the toxicity of these metals to tropical freshwater algae are currently available. The aim of this study was to develop a toxicity test for an Australian tropical freshwater alga that can be added to the suite of tests currently available for tropical freshwater invertebrates and fish. This toxicity test was used to investigate the toxicity of Cu and U to the alga Chlorella sp (new species) in a synthetic softwater and to specifically determine the effect of pH on metal toxicity over the range typically found in soft fresh surface waters in tropical northern Australia. A growth inhibition toxicity test was successfully developed for this alga, which was isolated from Kakadu National Park, Northern Territory, prior to conducting the toxicity testing. Key environmental parameters including light, temperature and nutrients were optimised to obtain acceptable algal growth rates over 72 hours. HEPES buffer (2 mM at pH 6.5) was found to be a suitable and practical option for pH control that could be incorporated in the test protocol for Chlorella sp. The results obtained in this study confirmed a lack of toxic effects by HEPES on the algae, as well as negligible complexation with both Cu and U. Adequate pH control (ie -1) than U (13 ?g L-1), and more sensitive than other Australian tropical freshwater species, with an order of sensitivity: Alga ?Crustacea > Cnidaria > Mollusca > Chordata. The toxicity of Cu and U was highly pH-dependent. Copper concentrations needed to inhibit growth by 50% (72 h EC50) increased from 1.5 to 35 ?g Cu L-1 as the pH decreased from 6.5 to 5.7. The 72 h EC50 for U increased from 44 to 78 ?g U L-1 over the same pH range. Decreased toxicity at pH 5.7 was due to lower concentrations of cell-bound and intracellular Cu and U compared to that at pH 6.5. These results are explained in terms of the possible mechanism of competition between H+ and the metal ion at the cell surface. The comparative sensitivity of Chlorella sp to Cu and U was also assessed. Chlorella sp was two times more sensitive to Cu than to U at pH 5.7 and up to 30 times more sensitive to Cu at pH 6.5 on a weight basis. However, on a molar basis, Chlorella sp was two times more sensitive to U than to Cu at pH 5.7. At pH 6.5, Cu was >8 times more toxic to the alga than U. This species was sensitive enough to detect adverse effects of Cu at the ANZECC guideline values of 5 ?g Cu L-1, making it a sensitive test organism for the assessment of Cu contamination of freshwaters. However, the unusual, often non-sigmoidal, concentration-response curve for Chlorella sp may reduce the reproducibility of the toxicity test. Despite this, Chlorella sp does possess a number of desirable characteristics for use in toxicity assessment and therefore is recommended to be used as part of a battery of toxicity tests with other local freshwater organisms. In particular, the alga's high sensitivity to Cu and U and environmental relevance make it a suitable choice for site-specific testing of mine wastewaters in tropical Australia. The findings obtained in this study have the potential to be incorporated into future revisions of the Australian water quality guidelines

1998-01-01

295

Po-210 and other radionuclides in terrestrial and freshwater environments  

International Nuclear Information System (INIS)

[en] This report provides new information on Po-210 (and where appropriate its grandparent Pb-210) behaviour in environmental systems including humans. This has primarily been achieved through measurements of Po-210 in aquatic and terrestrial environments that has led to the derivation of information on the levels of this radioisotope in plants, animals and the biotic components of their habitat (i.e. water, soil) providing basic information on transfer where practicable. For freshwater environments, Po-210 concentration ratios derived for freshwater benthic fish and bivalve mollusc were substantially different to values collated from earlier review work. For terrestrial environments, activity concentrations of Po-210 in small mammals (although of a preliminary nature because no correction was made for ingrowth from Pb-210) were considerably higher than values derived from earlier data compilations. It was envisaged that data on levels of naturally occurring radionuclides would render underpinning data sets more comprehensive and would thus allow more robust background dose calculations to be performed subsequently. By way of example, unweighted background dose-rates arising from internal distributions of Po-210 were calculated for small mammals in the terrestrial study. The biokinetics of polonium in humans has been studied following chronic and acute oral intakes of selected Po radioisotopes. This work has provided information on gastrointestinal absorption factors and biological retention times thus improving the database upon which committed effective doses to humans are derived. The information generated in the report, in its entirety, should be of direct relevance for both human and non-human impact assessments. (au)

2009-01-01

296

Po-210 and other radionuclides in terrestrial and freshwater environments  

Energy Technology Data Exchange (ETDEWEB)

This report provides new information on Po-210 (and where appropriate its grandparent Pb-210) behaviour in environmental systems including humans. This has primarily been achieved through measurements of Po-210 in aquatic and terrestrial environments that has led to the derivation of information on the levels of this radioisotope in plants, animals and the biotic components of their habitat (i.e. water, soil) providing basic information on transfer where practicable. For freshwater environments, Po-210 concentration ratios derived for freshwater benthic fish and bivalve mollusc were substantially different to values collated from earlier review work. For terrestrial environments, activity concentrations of Po-210 in small mammals (although of a preliminary nature because no correction was made for ingrowth from Pb-210) were considerably higher than values derived from earlier data compilations. It was envisaged that data on levels of naturally occurring radionuclides would render underpinning data sets more comprehensive and would thus allow more robust background dose calculations to be performed subsequently. By way of example, unweighted background dose-rates arising from internal distributions of Po-210 were calculated for small mammals in the terrestrial study. The biokinetics of polonium in humans has been studied following chronic and acute oral intakes of selected Po radioisotopes. This work has provided information on gastrointestinal absorption factors and biological retention times thus improving the database upon which committed effective doses to humans are derived. The information generated in the report, in its entirety, should be of direct relevance for both human and non-human impact assessments. (au)

Gjelsvik, Runhild; Brown, Justin (eds.) (Norwegian Radiation Protection Authority (Norway)); Holm, Elis (Univ. of Lund (Sweden)); Roos, Per (Risoe DTU (Denmark)); Saxen, Ritva; Outola, Iisa (STUK - Radiation and Nuclear Safety Authority (Finland))

2009-01-15

297

Phytochemical and Antibacterial Study of Five Freshwater Algal Species  

Directory of Open Access Journals (Sweden)

Full Text Available A phytochemical study of five freshwater algal species isolated from an Egyptian water station and comparing their inhibition activities against three selected bacterial pathogens in order to correlate the biological activity and the chemical constituents of the algae. Five freshwater algal species, Anabaena sphaerica, Chroococcus turgidus, Oscillatoria limnetica and Spirulina platensis (blue-green algae, Cyanobacteria) and Cosmarium leave (green algae) were isolated from an Egyptian water station and purified using BG11 media and cultivated. The alcoholic and the aqueous extracts of the five species were evaluated for their inhibitory effect against three bacterial pathogens: Escherichia coli, Salmonella Typhimurium and Streptococcus faecalis using poured plate method. A comparative phytochemical study was performed to detect the main active components of the tested extracts. The obtained results revealed that both the MeOH and the aqueous extracts of Spirulina showed noticeable inhibitory activity against the three bacterial strains: 91.6% (0.7 mg mL-1), 86.2% (0.5 mg mL-1) and 100% (0.3 mg mL-1) for MeOH. and 74.4% (0.9 mg mL-1), 99.3% (0.9 mg mL-1) and 72.6% (0.1 mg mL-1) for H2O against E. coli, Salmonella and Streptococcus, respectively in comparison with other algal extracts. The latter exerted different inhibition activities depending on the types of the bacteria and the extract. It could be concluded that the antibacterial activity was strongly correlated with the quercitin and pigment contents for the MeOH extract and the carbohydrates and pigments contents for the aqueous extract.

S.M. Abdo; M.H. Hetta; F.A. Samhan; R.A.S. El Din; G.H. Ali

2012-01-01

298

The use of biota sampling for environmental contaminant analysis for characterization of benthic communities in the Aleutians  

International Nuclear Information System (INIS)

It is increasingly clear that the public, native tribes, and governmental agencies are interested in assessing the well-being of natural resources and ecosystems. This may take the form of understanding species presence, monitoring population status and trends, measuring behavior, or quantifying physiology, biological stresses, or chemical/radiological exposure through biomarkers. Often there is a separation between understanding the biological aspects of species well-being and assessing exposure to contaminants. In this paper we examine the applicability of using scuba sampling aimed primarily at specimen collection for radionuclide analysis to assess species presence/absence and to compare among sampling sites and depths. We were especially interested in whether dive transects could provide information on species presence and potential exposure to environmental contaminants. In June/July 2004 we sampled at 49 depth stations along 19 transects at Amchitka and Kiska Islands in the western Aleutian Islands in the Northern Pacific/Bering Sea region. Amchitka Island, a former World War II U.S. Navy base, was the site of three underground nuclear test shots from 1965 to 1971. Four to six transects were established at three Amchitka sites and two Kiska Sites, and 2 to 4 stations were sampled on each transect. Bottom conditions, weather and currents prevented a complete sampling of all stations. There were interspecific differences in the percent of stations where biota were found and collected, in their occurrence near the three test shots on Amchitka, and in the depth where they were found. There were no significant differences between Amchitka and Kiska Island in the percent of stations where species were found. These data suggest that information gathered incidentally to the collection of specimens for chemical/radiological analysis can prove useful for understanding the presence of benthic organisms along particular transects, at given depths, and at different geographical locations. This information also provides a baseline for the range of organisms that could be exposed to future physical or chemical/radiological stressors. The data are useful for developing future biomonitoring plans to assess biological well-being and chemical/radiological exposure only if they are published and available to the public, public policy makers, and managers. Just as it is critical to select endpoints and bioindicators that are of interest for assessing both human and ecological health, specimens should be collected using a protocol that is useful for both chemical/radiological analysis and biological information

299

Assessment of heavy metal concentrations in water, sediment and biota (fish and crabs) samples from the Densu Delta  

International Nuclear Information System (INIS)

The aim of the study was assess the concentration of some selected heavy metals in water, sediments and biota (fish and crab) sampled from the Densu Delta. In situ and laboratory based analysis were carried out to measure the following physicochemical properties of surface water from the delta; temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), alkalinity, sodium ion concentration (Na+), potassium ion concentration (K+), chloride ion concentration (Cl), bicarbonate concentration, phosphate concentration, nitrate concentration, sulphate concentration and biochemical oxygen demand (BOD). Heavy metal (Fe, Zn, Cu, Ni, Cd, Cr, Pb and Hg) concentrations in water, sediments, fish and crab sampled at six sites from the Densu Delta wetland in the month of December, 2009 were analysed using VARIAN Fast Sequential Atomic Absorption Spectrophotometer (AAS) model AA240 FS. Two fish species; Blackchin tilapia (Sarotherodon melanotheron), White mullet (Mugil curema) and one species of crab; Blue swimming crab (Callinectes amnicola) were collected from the Densu Delta wetland and analysed. Heavy metal contents in the fish were higher in gill tissue than muscle tissue while in crabs concentrations were higher in the soft tissue than the shell. Levels of Fe, Zn and Cu in the muscle tissue of S. melanotheron were greater than the levels detected in the muscle tissue of M. curema. Cd, Ni and Hg were detected in gill tissue but not in the muscle tissue of S. melanotheron, M. curema on the other hand contained these metals in both gill and muscle tissue. The maximum level of Fe (34.98 mg/L), Zn (25.08 mg/L) in the muscle of S. melanotheron was observed at Bortianor and Zn (2.70 mg/L) was observed at Tetegu. In the M. curema, the maximum level of Fe (34.66 mg/L), Zn (15.9 mg/L) and Cu (1.43 mg/L) was detected at Aplaku, Tetegu and Faana respectively. Heavy metal concentrations were higher in sediment than water. The presence of elevated levels of Cd and Ni in the muscle tissue of the white mullet fish from Tetegu and Faana, is a potential public health hazard to the inhabitants of these two communities and other neighbouring communities who depend on fish from the delta as their source of protein. (au)

2010-01-01

300

Uptake, turnover and distribution of chlorinated fatty acids in aquatic biota  

Energy Technology Data Exchange (ETDEWEB)

Chlorinated fatty acids (CIFAs) are the major contributors of extractable, organically bound chlorine in fish lipids. A known anthropogenic source of CIFAs is chlorine bleached pulp production. Additional anthropogenic sources may exist, e.g., chlorine-containing discharge from industrial and household waste and they may also occur naturally. CIFAs have a wide geographic distribution. They have, for instance, been identified in fish both from Alaskan and Scandinavian waters. In toxicological studies of CIFAs, the most pronounced effects have been found in reproductive related processes. CIFAs have also been shown to disrupt cell membrane functions. The present study was carried out to further characterise the ecotoxicological properties of CIFAs and their presence in biota. To investigate the biological stability of CIFAs, two experiments were carried out using radiolabelled chlorinated and non-chlorinated fatty acids. In both experiments, CIFAs were taken up from food by fish and assimilated to lipids. From the first experiment it was concluded that the chlorinated fatty acid investigated was turned over in the fish to a lower degree than the non-chlorinated analogue. In the second experiment, the transfer of a chlorinated fatty acid was followed over several trophic levels and the chlorinated fatty acid was transferred to the highest trophic level. In samples with differing loads of persistent organic pollutants (POPs) from both fish and marine mammals, high concentrations and diversity of CIFAs were detected. This was also observed in samples with low POP concentration. Chlorohydroxy fatty acids made up a considerable portion of the CIFAs in certain samples, both from limnic fish and marine mammals. CIFAs in fish were found to be bound in complex lipids such as triacylglycerols (storage lipids) and phospholipids, as well as in acyl sterols (membrane lipids). In the marine mammals investigated, high concentrations of CIFAs were mainly bound in phospholipids. If CIFAs are assimilated like `normal` fatty acids, are incorporated into membrane lipids, and are recalcitrant to catabolism, they may thus give rise to ecotoxicological effects when released to the environment and accumulated in biota 55 refs, 1 fig

Bjoern, Helena

1999-09-01

 
 
 
 
301

The role of regional information in the dose rate estimation of biota: from the view point of stakeholder involvement  

International Nuclear Information System (INIS)

[en] A dose evaluation system developed to judge environmental radiation safety was proposed in order to evaluate the effect on environmental flora and fauna. However, it was noted that large differences exist between biota doses based on the regional data and those determined by the dose evaluation system developed. In order to realize successful mutual communication among stakeholders, information needed for environmental radiation protection has been investigated in various kinds of exposure situations, because the Japanese tend to act following the standards set by them to get the most appropriate results in the situations they are faced with. It became clear from the investigation on beliefs about environmental issues that the Japanese are concerned about regional characteristics of natural environments and biota through which they observe variations in their living conditions. Furthermore, the systematic approach for compilation of the regional environmental parameters and data becomes important to accomplish a social agreement on environmental safety. (author)

2008-01-01

302

Dynamics of radiation exposure to marine biota in the area of the Fukushima NPP in March-May 2011.  

UK PubMed Central (United Kingdom)

Estimates of radiation dose rates are presented for marine biota in March-May 2011 in the coastal zone near Fukushima NPP, and in the open sea. Calculations of fish contamination were made using two methods: a concentration factor approach, and a dynamic model. For representative marine organisms (fish and molluscs) the radiation dose rates did not exceed the reference level of 10 mGy/day. At a distance 30 km from the NPP, in the open sea the radiation doses for marine biota were much lower than those in the coastal zone near the NPP. Comparative estimates are presented for radiation doses to aquatic organisms in the exclusion zones of the Eastern Urals Radioactive Trail, and the Chernobyl NPP.

Kryshev II; Kryshev AI; Sazykina TG

2012-12-01

303

A comparison of trace element concentrations in biota from four irrigation projects in Wyoming  

Energy Technology Data Exchange (ETDEWEB)

Irrigation drainwater can or has the potential to cause the mobilization of trace elements into the food chain and adversely affect fish and aquatic birds. Because of the semi-arid climate, irrigation is a necessary component of agriculture in Wyoming. Biota from four irrigation projects in Wyoming were collected and analyzed for trace element concentrations between 1988 and 1990. The irrigation projects included: the Kendrick Reclamation Project, Natrona County; the Riverton Reclamation Project, Fremont County; the Shoshone Irrigation Project, Park and Bighorn counties; and the Wind River Irrigation Project, Fremont County. Selenium concentrations were elevated in aquatic vegetation, aquatic invertebrates, bird eggs, bird livers and fish from the Kendrick Reclamation Project. Reproductive impairment and embryo teratogenesis was documented at the Kendrick Reclamation Project. Trace element concentrations in most biological samples from the three other irrigation projects were less than levels suspected of causing adverse effects. However, at the Riverton Reclamation Project, selenium concentrations in some samples of aquatic vegetation, aquatic invertebrates, fish and fish eggs exceeded concentrations associated with adverse effects. Differences in selenium concentrations in the four irrigation projects can be explained by the extent of seleniferous formations and soils, and the presence of closed basin wetlands.

Ramirez, P. Jr.; Jennings, M.; Dickerson, K. [Fish and Wildlife Service, Cheyenne, WY (United States)

1994-12-31

304

Cernavoda NPP impact study on terrestrial and aquatic biota. Preliminary results  

International Nuclear Information System (INIS)

Recently, the awareness of the vulnerability of the environment has increased and the need to protect it against industrial pollutants has been recognized. The concept of sustainable development, requires new and developing international policies for environmental protection. See 'Protection of the environment from the effects of ionizing radiation' IAEA-TECDOC-1091, International Atomic Energy Agency, Vienna. As it is recommended in 'Cernavoda Unit No. 2 NPP Environmental Impact Assessment CES-03702-IAD-006', it is Cernavoda NPP responsibility to conduct an Ecological Risk Assessment study, mainly to assess the impact of nuclear power plant operation on terrestrial and aquatic biota. Long records from normal operation of Cernavoda Unit 1, wind pattern, meteorological conditions, and source terms data were used to evaluate areas of interest for environmental impact, conducting to a circle of 20 km radius around mentioned nuclear objective. The screening campaign established tritium level (because Cernavoda NPP is a CANDU type reactor, and tritium is the most important radioisotope evacuated in the environment) in air, water, soil and vegetation, focusing the interest area on particular ecosystem. Using these primary data it was evaluated which are the monitored ecological receptors and which are the measurement endpoints.This paper presents the Ecological Risk Assessment at Cernavoda NPP technical requirements, and the preliminary results of evaluating criteria for representative ecosystem components at Cernavoda NPP. (authors)

2010-01-01

305

Sediment distribution coefficients and concentration factors for biota in the marine environment  

International Nuclear Information System (INIS)

In 1985 the IAEA published Technical Reports Series No. 247 (TRS 247), Sediment Kds and Concentration Factors for Radionuclides in the Marine Environment, which provided sediment distribution coefficients (Kds) and concentration factor (CF) data for marine biological material that could be used in models simulating the dispersion of radioactive waste that had been disposed of in the sea. TRS 247 described an approach for calculating sediment or water Kds using stable element geochemical data developed by J.M. Bewers, even though the use of field derived data was emphasized whenever possible. Over the years, TRS 247 has proved to be a valuable reference for radioecologists, marine modellers and other scientists involved in assessing the impact of radionuclides in the marine environment. In 2000 the IAEA initiated a revision of TRS 247 to take account of the new sets of data obtained since 1985.The outcome of this work is this report, which contains revised sediment Kds for the open ocean and ocean margins and CFs for marine biota. CFs for deep ocean ferromanganese nodules. In addition, this report contains CFs for a limited number of elements for marine mammals not included in TRS 247. This revision was carried out at three IAEA Consultants Meetings held in Monaco and Vienna between April 2000 and December 2002

2004-01-01

306

Proposal of a weight factor for alpha radiation aiming biota radioprotection  

International Nuclear Information System (INIS)

Several proposals based on the environmental radioprotection of calculating the absorbed dose in biota have been suggested. The absorbed dose expresses the deposition of energy per mass unit. The differences in biological effects of the absorbed dose can be quantified by applying a correction factor to the absorbed dose. The correction factor for radiation is easier to establish, because radiations exist in smaller number (alpha, beta, neutrons and photons) and can be set for groups of organisms. This work aims to propose a correction factor for radiation, in order to adequate the concept of absorbed dose currently used to the concept of equivalent dose. A survey of the literature on correction factors proposed for alpha radiation was carried out and, when possible, the biological endpoint was identified, as well as the radionuclide and the biological target. A variation of the weight factor for alpha radiation from 1 to 377 was observed and a number of biological endpoints, biological target and alpha emitter radionuclide were identified. Finally we propose a weight value for alpha radiation of 40, and we propose also the name of correction factor for radiation alpha as being ecological radiation weighting factor (WRE) the name 'equivalent dose for flora and fauna' (HTFF) to name of the new dose. (author)

2009-10-02

307

Metal contamination in water, sediment and biota from a semi-enclosed coastal area.  

Science.gov (United States)

This study identifies and quantifies the spatial variations of metal contamination in water, sediment and biota: the common cockle (Cerastoderma edule) and the Mermaid's glove sponge (Haliclona oculata), within a heavily anthropogenically impacted semi-enclosed estuarine-coastal area with a low ability to disperse and flush contaminants (Poole Harbour, UK). The results showed that metal contamination was detected in all environmental compartments. Water was polluted with As, and Hg sediment metals were mostly within "the possible effect range" in which adverse effects occasionally occurs. Cockles had considerable concentrations of Ni, Ag and Hg in areas close to pollution sources, and sponges accumulate Cu and Zn with very high magnitude. A systematic monitoring approach that includes biological monitoring techniques, which covers all embayments, is needed, and an integrated management of the semi-enclosed coastal zones should be based on the overall hydrological characteristics of these sensitive areas and their ability to self-restore which is different than open coastal zones. PMID:23014922

Aly, Walid; Williams, Ian D; Hudson, Malcolm D

2012-09-27

308

Does soil biota benefit from organic farming in complex vs. simple landscapes  

UK PubMed Central (United Kingdom)

Organic farming can counteract detrimental effects of agricultural intensification on farmland biodiversity. Enhancing biodiversity with agri-environmental schemes is hypothesized to be more efficient in simple than complex landscapes, a pattern confirmed for many aboveground taxa. Although belowground biodiversity is an important part of the agroecosystem, studies on the interacting effects of local and landscape intensification on the belowground detritivore community, including bacteria, fungi, collembolans and earthworms are lacking. We sampled diversity and abundance of arable weeds, earthworms and collembolans, soil respiration rate and microbial biomass in 12 pairs of organically and conventionally managed fields in landscapes differing in structural complexity. Organic farming significantly enhanced species richness of arable weeds, while conventional farming enhanced soil respiration and abundance of Collembola with furca. This research shows that the landscape context plays a significant role in shaping effects of organic vs. conventional farming on soil biota. Earthworm species richness in simple landscapes, where predation pressure is reduced, was enhanced by organic farming, whereas in complex landscapes, conventional farming, which often causes reduced predation, fostered earthworm species richness. As the same pattern was found for microbial carbon biomass, earthworms may have enhanced microbial biomass. In contrast to earthworm and microbial diversity, aboveground biodiversity benefits most from organic farming in simple landscapes. In general, organic farming appears to be more efficient in conserving aboveground than belowground diversity.

Flohre A; Rudnick M; Traser G; Tscharntke T; Eggers T

2011-04-01

309

Screening for planar chlorobiphenyl congeners in marine biota by HPLC/PDA  

Energy Technology Data Exchange (ETDEWEB)

A rapid method has been developed to screen for the dioxin-like planar chlorobiphenyl (CB) congeners, as well as certain other CBs and DDTs, in tissue samples from marine biota. Following extraction, the analytes were separated from interfering compounds on a gravity-flow column packed with acidic, basic and neutral silica gel. Subsequently, the planar CB congeners were resolved from the DDTs and other CBs by HPLC on Cosmosil PYE analytical columns cooled to 9 C and were measured by an ultraviolet (UV) photodiode array (PDA) detector. Individual analytes were identified by comparing their UV spectra and retention to those of reference standards and analyte purity was established by comparing spectra within a peak to the apex spectrum. The HPLC/PDA method was tested with tissue samples from fish, shellfish and marine mammals. Concentrations of the planar CB congeners, as well as certain other CBs and DDTs, in samples determined by screening compared favorably with those in the same samples analyzed by a comprehensive method. The screening method required about 20% of the time needed for the comprehensive analyses. The authors demonstrated the utility of the HPLC/PDA method by determining CBs and DDTs in edible tissue from a variety of seafood species; preliminary results from this survey will be presented.

Krahn, M.M.; Ylitalo, G.M.; Buzitis, J.; Sloan, C.A.; Boyd, D.T.; Chan, S.L.; Varanasi, U. [NOAA/NMFS, Seattle, WA (United States)

1994-12-31

310

Contrasting food web factor and body size relationships with hg and se concentrations in marine biota.  

UK PubMed Central (United Kingdom)

Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by ?(15)N) and degree of pelagic feeding (measured by ?(13)C). Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans.

Karimi R; Frisk M; Fisher NS

2013-01-01

311

Contrasting Food Web Factor and Body Size Relationships with Hg and Se Concentrations in Marine Biota  

Science.gov (United States)

Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by ?15N) and degree of pelagic feeding (measured by ?13C). Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans.

Karimi, Roxanne; Frisk, Michael; Fisher, Nicholas S.

2013-01-01

312

Technetium-99 in biota samples collected along the Finnish coast in 1999  

International Nuclear Information System (INIS)

The aim of the study was to develop a method for analysing 99Tc at STUK (Radiation and Nuclear Safety Authority in Finland), and to establish whether 99Tc can be detected in Finnish coastal waters. Samples of Fucus vesiculosus, Myriophyllum spp., Macoma baltica, Mytilus edulis, Saduria entomon and seawater were collected at more than 30 stations along the western and southern coasts of Finland for 99Tc analysis. Small amounts of 99Tc were observed in all the Fucus samples collected; the activity concentrations ranged from 1.6 to 11.6 Bq kg-1 dry wt. The highest concentrations were found in two samples taken from the northernmost stations in the Quark, probably for biological reasons. Due to the low salinity of the water, Fucus vesiculosus is very slow-growing and small in this area, which is at the extreme limit of its permanent distribution range in the Baltic Sea. In seawater and in all the other biota samples, the concentration of 99Tc was below the detection limit, which supports the use of Fucus as an indicator organism for 99Tc in the marine environment. Global fallout from atmospheric nuclear weapons tests carried out in the 1950s and 1960s is certainly the most important source of 99Tc detected in Fucus on the Finnish coast. In addition, the samples were analysed for gamma- emitting radionuclides. (orig.)

2002-01-01

313

Technetium-99 in biota samples collected along the Finnish coast in 1999  

Energy Technology Data Exchange (ETDEWEB)

The aim of the study was to develop a method for analysing {sup 99}Tc at STUK (Radiation and Nuclear Safety Authority in Finland), and to establish whether {sup 99}Tc can be detected in Finnish coastal waters. Samples of Fucus vesiculosus, Myriophyllum spp., Macoma baltica, Mytilus edulis, Saduria entomon and seawater were collected at more than 30 stations along the western and southern coasts of Finland for {sup 99}Tc analysis. Small amounts of {sup 99}Tc were observed in all the Fucus samples collected; the activity concentrations ranged from 1.6 to 11.6 Bq kg{sup -1} dry wt. The highest concentrations were found in two samples taken from the northernmost stations in the Quark, probably for biological reasons. Due to the low salinity of the water, Fucus vesiculosus is very slow-growing and small in this area, which is at the extreme limit of its permanent distribution range in the Baltic Sea. In seawater and in all the other biota samples, the concentration of {sup 99}Tc was below the detection limit, which supports the use of Fucus as an indicator organism for {sup 99}Tc in the marine environment. Global fallout from atmospheric nuclear weapons tests carried out in the 1950s and 1960s is certainly the most important source of {sup 99}Tc detected in Fucus on the Finnish coast. In addition, the samples were analysed for gamma- emitting radionuclides. (orig.)

Ilus, E.; Vartti, V.-P.; Ikaeheimonen, T.K.; Mattila, J.; Klemola, S. [Radiation and Nuclear Safety Authority, Helsinki (Finland)

2002-07-01

314

Steady-state model of biota sediment accumulation factor for metals in two marine bivalves  

Energy Technology Data Exchange (ETDEWEB)

A model of the biota sediment accumulation factor (BSAF) is developed to relate the ratio of metal concentrations in two marine bivalves (Crassostrea virginica and Mytilus edulis) to sediment metal concentration. A generalized metal BSAF can be approximated by a simple relationship that is a function of sediment to water column partitioning, the bioconcentration factor (BCF), the depuration rate, the metal assimilation efficiency from food, the bivalve feeding rate, and the growth rate. Analyses of Mussel Watch data indicate that the medium BSAF across stations varies by about three orders of magnitude from Zn, Cd, and Cu at the highest levels of BSAF = 1 to 10, while Cr has the lowest BSAF at 0.01. Total Hg is about 1.0 and Ni and Pb are approximately 0.1. Calibration of the model indicates that the food route of metal accumulation is significant for all metals but specially for Zn, Cd, Cu, and Hg where virtually all of the observed BSAF is calculated to be due to ingestion of metal from food in the overlying water. These results indicate a potential significance of the metal-binding protein metallothionein, which results in relatively high binding of metal and resulting low depuration rates.

Thomann, R.V.; Mahony, J.D. [Manhattan Coll., Riverdale, NY (United States). Dept. of Environmental Engineering; Mueller, R. [Havens and Emerson, Saddle Brook, NJ (United States)

1995-11-01

315

Persistent organic pollutants in marine biota of Sao Pedro and Sao Paulo Archipelago, Brazil.  

UK PubMed Central (United Kingdom)

Remote islands, such as the São Pedro and São Paulo Archipelago (SPSPA), Brazil, are pristine areas. However, these locations are not exempt from the arrival of anthropogenic agents, such as persistent organic pollutants (POPs). The present study aimed to determine the occurrence and distribution of POPs in the marine biota of the SPSPA. Sample extractions were performed using a microwave-assisted method. The predominant compounds were PCBs and DDTs, which respectively had mean wet weight concentrations of 62.23 and 9.23ngg(-1) in the tropical two-wing flying fish (Exocoetus volitans), 78.66 and 6.81ngg(-1) in the brown booby (Sula leucogaster) and 43.40 and 3.03ngg(-1) in the red rock crab (Grapsus grapsus). Low levels of contaminants suggest a relative degree of isolation. Occurrence and distribution profiles of PCBs support long-range atmospheric transport as the main source of contamination and demonstrate the ubiquity of these pollutants in the marine environment.

Dias PS; Cipro CV; Taniguchi S; Montone RC

2013-09-01

316

Distribution of hexabromocyclododecane diastereomers in marine biota in the Western Scheldt Estuary  

Energy Technology Data Exchange (ETDEWEB)

Hexabromocyclododecane (HBCD) is one of the most common additive flame retardant mainly used in polystyrene foams with the global market consumption in 2001 at about 16 700 tons.1 HBCD production results in a technical product consisting mostly of three diastereomers, {alpha}-, {beta}-, and {gamma}-HBCD, with the {gamma}-isomer being the predominant one. HBCD has a high bioaccumulation potential and bioavailability and has been found in increasing concentrations in environmental samples and in biota. Diastereoisomer-specific analysis of HBCD was achieved by reversed phase HPLC4 and consistently higher concentrations of the {alpha}-isomer compared to {gamma}-isomer have recently been reported, while the {beta}-isomer was non-detected in the majority of samples. The Western Scheldt Estuary is subjected to a variety of suspected brominated flame retardants (BFR) sources such as a BFR manufacturing plant (Terneuzen, The Netherlands), the Antwerp harbour and textile industry located further upstream the river. Recently, polybrominated diphenyl ethers (PBDEs) were investigated in marine species of different trophic levels collected from the Scheldt Estuary. In Europe, HBCD is more widely used than PBDEs and high levels of HBCD have already been reported in sediments from the Scheldt. So far, there is very little known about differences in toxicity, bioavailability and bioaccumulation of HBCD diastereoisomers. In this paper, we report on the levels of the HBCD diastereomers in various marine species and sediment from the Western Scheldt.

Janak, K. [Norwegian Institute of Public Health, Oslo (Norway). Div. of Environmental Medicine; Covaci, A.; Voorspoels, S. [Antwerp Univ., Wilrijk (Belgium). Toxicological Centre

2004-09-15

317

Determining the response of African biota to climate change: using the past to model the future  

Science.gov (United States)

Prediction of biotic responses to future climate change in tropical Africa tends to be based on two modelling approaches: bioclimatic species envelope models and dynamic vegetation models. Another complementary but underused approach is to examine biotic responses to similar climatic changes in the past as evidenced in fossil and historical records. This paper reviews these records and highlights the information that they provide in terms of understanding the local- and regional-scale responses of African vegetation to future climate change. A key point that emerges is that a move to warmer and wetter conditions in the past resulted in a large increase in biomass and a range distribution of woody plants up to 400–500 km north of its present location, the so-called greening of the Sahara. By contrast, a transition to warmer and drier conditions resulted in a reduction in woody vegetation in many regions and an increase in grass/savanna-dominated landscapes. The rapid rate of climate warming coming into the current interglacial resulted in a dramatic increase in community turnover, but there is little evidence for widespread extinctions. However, huge variation in biotic response in both space and time is apparent with, in some cases, totally different responses to the same climatic driver. This highlights the importance of local features such as soils, topography and also internal biotic factors in determining responses and resilience of the African biota to climate change, information that is difficult to obtain from modelling but is abundant in palaeoecological records.

Willis, K. J.; Bennett, K. D.; Burrough, S. L.; Macias-Fauria, M.; Tovar, C.

2013-01-01

318

Plutonium isotopes in marine sediments and some biota from the Sudanese coast of the Red Sea  

International Nuclear Information System (INIS)

[en] Measurements of 239+240Pu and 238Pu were carried out on marine biota as well as on sediments from the fringing reefs area extending towards north and south (Flamingo Bay) of Port Sudan harbour. The analyses were performed using radiochemical separation and alpha spectrometry. The range of the activity concentrations in marine sediments, in mBq kg-1 dry weight, was found to be from 5.10 to 82.00 for 239+240Pu and from 0.89 to 8.63 for 238Pu. Corresponding activity concentrations of 239+240Pu and 238Pu in sediments from the harbours at Port Sudan and Sawakin were 53-301 and 8.29-28.6 (Port Sudan) and 163-343 and 4.7 (Sawakin), respectively. The higher values for plutonium in marine algae suggest their suitability as an indicator species for monitoring purposes. The results obtained are generally lower than those found by other studies and show that the Red Sea environment is mildly affected by plutonium contamination. Activity ratios of plutonium isotopes confirm that the existence of plutonium in the Red Sea is mainly due to atmospheric global fallout. (authors)

2008-01-01

319

Biological studies of atmospheric deposition impact on biota in Kola North Mountain Lakes, Russia  

Energy Technology Data Exchange (ETDEWEB)

In the framework of the AL:PE projects, biological studies of phyto-, zooplankton and zoobenthos communities of a small lakes situated in Chuna tundra and Chibiny mountains in Murmansk region were performed in 1993-1995. The lakes are the typical oligotrophic mountain lakes. In the Chibiny lake phytoplankton were presented mostly by species from rock catchment area. Summer phytoplankton state in the lakes showed no acidification in 1993-1995. However, the great number dead cells of acid tolerance diatoms, such as Tabellaria flocculosa found in the Chuna lake in summer period, may indicate a presence of acid episodes. Zooplankton of the lakes is typical for high oligotrophic mountain lakes. However, lack of the acid sensitive daphniidae cladocerans seems to be a result of acidification effects. There were no significant relationships between benthic invertebrates species composition and present water acidity of the lakes. The typical for mountain lakes taxa (Prodiamesinae chironomids, stone flies and mayflies) were found in lake shore and streams. Despite the only little evidence of damage in biota, the further biological studies would be useful for long-term monitoring of the mountain lakes.

Yakovlev, V.; Sharov, A.; Vandysh, O. [Institute of the North Industrial Ecology Problems, Murmansk (Russian Federation)

1996-12-31

320

Evolutionary lag times and recent origin of the biota of an ancient desert (Atacama-Sechura).  

Science.gov (United States)

The assembly of regional biotas and organismal responses to anthropogenic climate change both depend on the capacity of organisms to adapt to novel ecological conditions. Here we demonstrate the concept of evolutionary lag time, the time between when a climatic regime or habitat develops in a region and when it is colonized by a given clade. We analyzed the time of colonization of four clades (three plant genera and one lizard genus) into the Atacama-Sechura Desert of South America, one of Earth's driest and oldest deserts. We reconstructed time-calibrated phylogenies for each clade and analyzed the timing of shifts in climatic distributions and biogeography and compared these estimates to independent geological estimates of the time of origin of these deserts. Chaetanthera and Malesherbia (plants) and Liolaemus (animal) invaded arid regions of the Atacama-Sechura Desert in the last 10 million years, some 20 million years after the initial onset of aridity in the region. There are also major lag times between when these clades colonized the region and when they invaded arid habitats within the region (typically 4-14 million years). Similarly, hyperarid climates developed ?8 million years ago, but the most diverse plant clade in these habitats (Nolana) only colonized them ?2 million years ago. Similar evolutionary lag times may occur in other organisms and habitats, but these results are important in suggesting that many lineages may require very long time scales to adapt to modern desertification and climatic change. PMID:23798420

Guerrero, Pablo C; Rosas, Marcelo; Arroyo, Mary T K; Wiens, John J

2013-06-24

 
 
 
 
321

Evolutionary lag times and recent origin of the biota of an ancient desert (Atacama-Sechura).  

UK PubMed Central (United Kingdom)

The assembly of regional biotas and organismal responses to anthropogenic climate change both depend on the capacity of organisms to adapt to novel ecological conditions. Here we demonstrate the concept of evolutionary lag time, the time between when a climatic regime or habitat develops in a region and when it is colonized by a given clade. We analyzed the time of colonization of four clades (three plant genera and one lizard genus) into the Atacama-Sechura Desert of South America, one of Earth's driest and oldest deserts. We reconstructed time-calibrated phylogenies for each clade and analyzed the timing of shifts in climatic distributions and biogeography and compared these estimates to independent geological estimates of the time of origin of these deserts. Chaetanthera and Malesherbia (plants) and Liolaemus (animal) invaded arid regions of the Atacama-Sechura Desert in the last 10 million years, some 20 million years after the initial onset of aridity in the region. There are also major lag times between when these clades colonized the region and when they invaded arid habitats within the region (typically 4-14 million years). Similarly, hyperarid climates developed ?8 million years ago, but the most diverse plant clade in these habitats (Nolana) only colonized them ?2 million years ago. Similar evolutionary lag times may occur in other organisms and habitats, but these results are important in suggesting that many lineages may require very long time scales to adapt to modern desertification and climatic change.

Guerrero PC; Rosas M; Arroyo MT; Wiens JJ

2013-07-01

322

Nuclear explosives, ionizin.o. radiation and the effects on the biota of the natural environment  

International Nuclear Information System (INIS)

[en] After giving a general discussion of nuclear explosives, weapons testing and peaceful use of nuclear explosives under Plowshare project, ecological studies carried out at weapon test sites and Plowshare project sites in United States are reviewed. It is noted that though considerable data are available on the behaviour of radionuclides in natural environments on these sites, only a few observations of effects of ionizing radiations on the biota of the natural environments of these sites have been made. The major effects on the natural environments of these sites have been attributed to physical effects of nuclear detonations and site preparation. These effects are physical destruction of plants and animals and habitat modification such as soil disturbances. Recolonization of ground zeros and adjacent areas is observed to follow the successional pattern unique to the site. Observed effects of ionizing radiation on shrubs in the vicinity of cratering tests appear to be inconsequential when one considers the ecosystem as a whole. (M.G.B.)

1980-01-01

323

[Fungal biota in manned space environment and impact on human health].  

UK PubMed Central (United Kingdom)

It is important to promote microbiological research essential for long-term manned space activities under microgravity and in a completely closed environment in space craft in relation to long-duration space expeditions on the International Space Station (ISS) or to the moon and Mars in the future. Environmental monitoring data from the space shuttle, the Mir, and the ISS have already shown that microorganisms isolated from air and on inner surfaces of space craft were generally carried by crew members. The Japanese Experiment Module (JEM) "KIBO" was attached to the ISS and started its operation from 2008. It is an invaluable opportunity to begin the survey of the transition of microbiota, particularly fungal biota, in JEM from "brand-new" to "well-used" condition at various periods. Therefore, we are preparing the on-board analyzing systems for microbiota in air and on inner surfaces of ISS/JEM and normal microbiota of the astronauts themselves. In this paper, we introduce the current status and future plans on fungal research on ISS/JEM to protect flight crew members and flight hardware from potentially hazardous microorganisms from the environmental and biomedical aspects of Japan Aerospace Exploration Agency (JAXA).

Makimura K; Satoh K; Sugita T; Yamazaki T

2011-01-01

324

Contrasting food web factor and body size relationships with hg and se concentrations in marine biota.  

Science.gov (United States)

Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by ?(15)N) and degree of pelagic feeding (measured by ?(13)C). Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans. PMID:24019976

Karimi, Roxanne; Frisk, Michael; Fisher, Nicholas S

2013-09-03

325

Determining the response of African biota to climate change: using the past to model the future.  

UK PubMed Central (United Kingdom)

Prediction of biotic responses to future climate change in tropical Africa tends to be based on two modelling approaches: bioclimatic species envelope models and dynamic vegetation models. Another complementary but underused approach is to examine biotic responses to similar climatic changes in the past as evidenced in fossil and historical records. This paper reviews these records and highlights the information that they provide in terms of understanding the local- and regional-scale responses of African vegetation to future climate change. A key point that emerges is that a move to warmer and wetter conditions in the past resulted in a large increase in biomass and a range distribution of woody plants up to 400-500 km north of its present location, the so-called greening of the Sahara. By contrast, a transition to warmer and drier conditions resulted in a reduction in woody vegetation in many regions and an increase in grass/savanna-dominated landscapes. The rapid rate of climate warming coming into the current interglacial resulted in a dramatic increase in community turnover, but there is little evidence for widespread extinctions. However, huge variation in biotic response in both space and time is apparent with, in some cases, totally different responses to the same climatic driver. This highlights the importance of local features such as soils, topography and also internal biotic factors in determining responses and resilience of the African biota to climate change, information that is difficult to obtain from modelling but is abundant in palaeoecological records.

Willis KJ; Bennett KD; Burrough SL; Macias-Fauria M; Tovar C

2013-01-01

326

Natural populations of plants and animals as test objects in ecological and genetic assessment of STS biota and population  

International Nuclear Information System (INIS)

Anthropogenic activities result in degradation of natural landscapes and biota impoverishment, disturb historical biocenoses relationships and thus unbalance the ecological system. Rare and few in number plant and animal species vanish and simplify the structure of plant and animal communities. Under unstable landscape conditions and growing impact of stress-inducing anthropogenic factors, populations of living organisms fall into several small isolated sub-populations that impoverishes the gene pool. (author)

2003-01-01

327

Assessment of doses to non-human biota: Review of developments and demonstration assessment for Olkiluoto repository  

International Nuclear Information System (INIS)

[en] This report provides a summary of work commissioned by Posiva Oy and undertaken by Enviros Consulting Ltd to support the development of a strategy for the assessment of environmental impacts from ionising radiation associated with the Olkiluoto waste repository, Finland, as part of the development of the Posiva Safety Case Portfolio. This project included a review of the development of international policies and standards related to protection of biota from the effects of ionizing radiation and of biota assessment methodologies, paying particular attention to those that have been applied to waste repository performance assessments. On the basis of this review, recommendations were developed on the most appropriate methodology to apply in order to assess the impact of radioactive releases from the planned spent fuel repository in Olkiluoto. A test-case was developed, in collaboration with staff from Posiva and Facilia AB, and an assessment was performed. The results and experience of which were analysed and summarised to develop recommendations for a future strategy. The test case highlighted some significant data gaps related to the assessment of impacts to both generic biota types and to interest species. In particular, concentration ratios for generic carnivorous mammals and migratory species such as moose that may consume food from multiple ecosystems and dose conversion factors for large burrowing (i.e. hibernating) mammals. However, in general terms, the dose rates predicted for all organism types were several orders of magnitude below those at which population effects would be expected to be observed and those at which effects on the individual may be anticipated. There would therefore be scope for simplifying the approach applied, although there would be value in performing a sensitivity analysis to ensure that the simplification is applied appropriately. There would also be value in ensuring consistency of the developing approach for non-human biota with that applied for human protection. (orig.)

2006-01-01

328

Radioactivity of plutonium isotopes, 137Cs and their ratio in sediment, seawater and biota from the east coast of Peninsular Malaysia  

International Nuclear Information System (INIS)

This study with sampling expeditions of marine sediment, seawater and biota were performed at 30 stations within Malaysian Exclusive Economic Zone (EEZ). A total of >400 samples were collected to determine the activity concentration of anthropogenic radionuclides (239+240Pu, 137Cs) and their activity ratio (239+240Pu/137Cs) in sediments, seawater and biota. The purpose of this study was to determine the concentration levels for these radionuclides and to evaluate any occurrence of radioactive contamination. Sediment cores were obtained using multicorer device, while water samples via co-precipitation techniques and biota was purchased from local fishermen. The activity concentrations of 239+240Pu in sediment, seawater and biota were ranged 0.21-0.45 Bq/kg fresh wt., respectively. Meanwhile, the values of 137Cs were ranged 3 in seawater and 239+240Pu to 137Cs obtained seem to confirm that these artificial radioactivities were mainly due to global nuclear fallout. (author)

2011-01-01

329

Baseline assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya, India  

International Nuclear Information System (INIS)

Radiation dose-risk assessment was carried out for cereal species Brassica compestris var. dichotoma, Oryza sativa var. Shalum1, Zea mays, Lactuca indica, Cumunis sativum, and Clocasia esculanta due to naturally available radionuclides 40K, 238U and 232Th in Domiasiat area. The activity in biota and corresponding soil was measured by precipitation method using NaI(TI) detector. Transfer factor (TF) was for Oryza spp. (1.00E-01-40K, 8.76E-05-232Th, and 9.11E-05-238U), for Brassica spp. (5.39E-01-40K, 8.17E-04-232Th and 2.96E-04-238U) and for Zea spp. (3.41E-01-40K, 5.84E-05-232Th, 8.87E-05-238U) etc., respectively. A detailed physio-morphological study of the biota and extensive investigation of ecosystem was carried out for assessment. The data was modeled using FASSET for dose estimation and obtained total dose was 1.58E-04 ?Gy h-1 in Oryza spp., 2.87E-04 ?Gy h-1 Brassica spp. and 6.90E-03 ?Gy h-1 in Zea spp. etc. The dose was compared with the UNSCEAR dataset for screening level dose for biota. Zea spp. was more susceptible for the chronic radiation exposure. (author)

2011-01-01

330

Review of research on impacts to biota of discharges of naturally occurring radionuclides in produced water to the marine environment.  

UK PubMed Central (United Kingdom)

Produced water has been described as the largest volume waste stream in the exploration and production process of oil and gas. It is accompanied by discharges of naturally occurring radionuclides raising concerns over the potential radiological impacts of produced water on marine biota. In the Northern European marine environment, radioactivity in produced water has received substantial attention owing to the OSPAR Radioactive Substances Strategy which aims at achieving 'concentrations in the environment near background values for naturally occurring radioactive substances'. This review provides an overview of published research on the impacts to biota from naturally occurring radionuclides discharged in produced water by the offshore oil and gas industry. In addition to summarising studies and data that deal directly with the issue of dose and effect, the review also considers studies related to the impact of added chemicals on the fate of discharged radionuclides. The review clearly illustrates that only a limited number of studies have investigated possible impacts on biota from naturally occurring radionuclides present in produced water. Hence, although these studies indicate that the risk to the environment from naturally occurring radionuclides discharged in produced water is negligible, the substantial uncertainties involved in the assessments of impact make it difficult to be conclusive. With regard to the complexity involved in the problem under consideration there is a pressing need to supplement existing data and acquire new knowledge. Finally, the present work identifies some knowledge gaps to indicate future research requirements.

Hosseini A; Brown JE; Gwynn JP; Dowdall M

2012-11-01

331

Range size patterns in European freshwater trematodes  

DEFF Research Database (Denmark)

Aim We investigated the relationship between host and parasite diversity as well as latitudinal gradients in parasite diversity on a continental scale in European freshwater trematodes. Location European freshwaters. Methods We extracted distributional data for 564 freshwater trematodes across 25 biogeographical regions in Europe from the Limnofauna Europaea and used multiple regression analyses to test for correlations between the diversity of definitive (vertebrates) or first intermediate (gastropods) hosts and that of trematodes, and for latitudinal gradients in trematode diversity. In particular, we investigated patterns in beta diversity among latitudinal bands and between trematode species that parasitize host groups with low (autogenic) and high (allogenic) dispersal capacity.We also tested for a latitudinal gradient in the proportional representation of these two trematode groups within regional faunas. Results Latitude or first intermediate host richness had no effect on trematode richness, but definitive host richness was a strong predictor of trematode richness, among both allogenic and autogenic parasites. We found that beta diversity of trematode faunas within latitudinal bands decreased to the north, with similar values for allogenic and autogenic trematodes. Finally, we observed an increasing proportion of autogenic species toward the north of Europe. Main conclusions The richness of definitive hosts appears to be the driver of trematode diversity at a continental scale. The latitudinal gradient in beta diversity reflects patterns observed in free-living species and probably results from recolonization in the aftermath of the ice ages. The similar beta-diversity patterns of allogenic and autogenic trematodes and the increasing proportion of autogenic trematodes with increasing latitude are surprising.We suggest that the geographical scale of our analysis or confounding factors such as differences in habitat utilization and specialization may partly explain these patterns.

Thieltges, David; Hof, Christian

2011-01-01

332

Accounting for the dissociating properties of organic chemicals in LCIA: an uncertainty analysis applied to micropollutants in the assessment of freshwater ecotoxicity.  

UK PubMed Central (United Kingdom)

In life cycle impact assessment (LCIA) models, the sorption of the ionic fraction of dissociating organic chemicals is not adequately modeled because conventional non-polar partitioning models are applied. Therefore, high uncertainties are expected when modeling the mobility, as well as the bioavailability for uptake by exposed biota and degradation, of dissociating organic chemicals. Alternative regressions that account for the ionized fraction of a molecule to estimate fate parameters were applied to the USEtox model. The most sensitive model parameters in the estimation of ecotoxicological characterization factors (CFs) of micropollutants were evaluated by Monte Carlo analysis in both the default USEtox model and the alternative approach. Negligible differences of CFs values and 95% confidence limits between the two approaches were estimated for direct emissions to the freshwater compartment; however the default USEtox model overestimates CFs and the 95% confidence limits of basic compounds up to three orders and four orders of magnitude, respectively, relatively to the alternative approach for emissions to the agricultural soil compartment. For three emission scenarios, LCIA results show that the default USEtox model overestimates freshwater ecotoxicity impacts for the emission scenarios to agricultural soil by one order of magnitude, and larger confidence limits were estimated, relatively to the alternative approach.

Morais SA; Delerue-Matos C; Gabarrell X

2013-03-01

333

Effects of water hardness and alkalinity on the toxicity of uranium to a tropical freshwater hydra (Hydra viridissima).  

UK PubMed Central (United Kingdom)

In tropical Australian freshwaters, uranium (U) is of potential ecotoxicological concern, largely as a consequence of mining activities. Although the toxicity of uranium to Australian freshwater biota is comprehensive, by world standards, few data are available on the effects of physicochemical variables, such as hardness, alkalinity, pH and organic matter, on uranium speciation and bioavailability. This study determined the individual effects of water hardness (6.6, 165 and 330 mg l(-1) as CaCO3) and alkalinity (4.0 and 102 mg l(-1) as CaCO3), at a constant pH (6.0), on the toxicity (96 h population growth) of uranium to Hydra viridissima (green hydra). A 50-fold increase in hardness (Ca and Mg concentration) resulted in a 92% (two-fold) decrease in the toxicity of uranium to H. viridissima [i.e. an increase in the EC50 value and 95% confidence interval from 114 (107-121) to 219 (192-246) µg l(-1)]. Conversely, at a constant hardness (165 mg l-1 as CaCO3), the toxicity of uranium to H. viridissima was not significantly (P > 0.05) affected by a 25-fold increase in alkalinity (carbonate concentration) [i.e. EC50 values of 177 (166-188) and 171 (150-192) µg l(-1) at 4.0 and 102 mg l(-1) as CaCO3, respectively]. A knowledge of the relationship between water chemistry variables, including hardness and alkalinity, and uranium toxicity is useful for predicting the potential ecological detriment in aquatic systems, and can be used to relax national water quality guidelines on a site-specific basis.

Riethmuller N; Markich SJ; Van Dam RA; Parry D

2001-01-01

334

Effects of water hardness and alkalinity on the toxicity of uranium to a tropical freshwater hydra (Hydra viridissima).  

Science.gov (United States)

In tropical Australian freshwaters, uranium (U) is of potential ecotoxicological concern, largely as a consequence of mining activities. Although the toxicity of uranium to Australian freshwater biota is comprehensive, by world standards, few data are available on the effects of physicochemical variables, such as hardness, alkalinity, pH and organic matter, on uranium speciation and bioavailability. This study determined the individual effects of water hardness (6.6, 165 and 330 mg l(-1) as CaCO3) and alkalinity (4.0 and 102 mg l(-1) as CaCO3), at a constant pH (6.0), on the toxicity (96 h population growth) of uranium to Hydra viridissima (green hydra). A 50-fold increase in hardness (Ca and Mg concentration) resulted in a 92% (two-fold) decrease in the toxicity of uranium to H. viridissima [i.e. an increase in the EC50 value and 95% confidence interval from 114 (107-121) to 219 (192-246) µg l(-1)]. Conversely, at a constant hardness (165 mg l-1 as CaCO3), the toxicity of uranium to H. viridissima was not significantly (P > 0.05) affected by a 25-fold increase in alkalinity (carbonate concentration) [i.e. EC50 values of 177 (166-188) and 171 (150-192) µg l(-1) at 4.0 and 102 mg l(-1) as CaCO3, respectively]. A knowledge of the relationship between water chemistry variables, including hardness and alkalinity, and uranium toxicity is useful for predicting the potential ecological detriment in aquatic systems, and can be used to relax national water quality guidelines on a site-specific basis. PMID:23886056

Riethmuller, N; Markich, S J; Van Dam, R A; Parry, D

2001-01-01

335

Freshwater clams as bioconcentrators of avian influenza virus in water.  

UK PubMed Central (United Kingdom)

We report experimental evidence for bioconcentration of a low-pathogenicity avian influenza virus (H6N8) in the tissue of freshwater clams. Our results support the concept that freshwater clams may provide an effective tool for use in the early detection of influenza A viruses in aquatic environments.

Huyvaert KP; Carlson JS; Bentler KT; Cobble KR; Nolte DL; Franklin AB

2012-10-01

336

Radiation Dose Assessment For The Biota Of Terrestrial Ecosystems In The Shoreline Zone Of The Chernobyl Nuclear Power Plant Cooling Pond  

International Nuclear Information System (INIS)

Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90Sr and 137Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

2011-10-01

337

Issues in Ecology, Issue 10: Sustaining Healthy Freshwater Ecosystems  

Science.gov (United States)

This report addresses the conservation of freshwater ecosystems within the United States. A comparison of the pre-settlement and current conditions of U.S. freshwater resources is provided. Requirements for maintaining freshwater ecosystem physical and biotic components, such as flow patterns, sediment/organic inputs, temperature, light, chemical/nutrient conditions, and plant/animal assemblages are discussed. Freshwater ecosystem management case studies on the Colorado River, the Great Lakes, and South Florida are presented. The report also elaborates on the need to balance human use against needs of freshwater ecosystems. Issues in Ecology is an ongoing series of reports designed to present major ecological issues in an easy-to-read manner. This Issue summarizes the consensus of a panel of scientific experts based on the information that was current and available at the time of its publication in 2003.

Jackson, Robert

2010-02-16

338

Effects of cadmium stress and sorption kinetics on tropical freshwater periphytic communities in indoor mesocosm experiments.  

Science.gov (United States)

Understanding the cause and effect relationship between stressors and biota is crucial for the effective management, restoration and preservation of aquatic systems. The objective of the present study was to assess the effects of five Cd concentrations on tropical periphyton community growth, Cd accumulation kinetics, as well as the effects of Cd on diatom community structure and composition. Natural periphyton communities were transferred to artificial stream chambers and exposed to Cd concentrations of 0.005, 0.01, 0.03, 0.05 and 0.1mg.L(-1). Metal accumulation (total and intracellular) in biofilms, dry weight and ash-free dry mass, growth rate, algal cell density and diatom community composition were analysed on samples collected after 1, 2 and 4 weeks of colonization. Periphyton growth and development were significantly lowered by Cd concentrations>0.03 mg.L(-1). High Cd accumulation capacity by periphyton was demonstrated with total and intracellular Cd content in biofilms reflecting the effects of concentrations of Cd in the culture media and exposure duration. Total and intracellular Cd content generally increased in treatments in the order 0.005<0.01<0.03<0.05<0.1mg.L(-1) at any sampling time with increasing level of accumulated Cd with duration of exposure in all the systems. Shifts in species composition (development of more resistant species like Achnanthidium minutissimum and reduction of sensitive ones like Diatoma vulgare, Navicula viridula and Navicula cryptocephala), decreases in species richness and diversity and morphological alterations (deformities) of diatom cells with increasing Cd concentration and exposure duration were observed. The results give valuable information on Cd impact of freshwater biofilms. PMID:22728297

Bere, Taurai; Tundisi, José Galizia

2012-06-20

339

Radiological benchmarks for screening contaminants of potential concern for effects on aquatic biota at Oak Ridge National Laboratory, Oak Ridge, Tennessee  

International Nuclear Information System (INIS)

[en] A hazardous waste site may contain hundreds of contaminants; therefore, it is important to screen contaminants of potential concern for the ecological risk assessment. Often this screening is done as part of a screening assessment, the purpose of which is to evaluate the available data, identify data gaps, and screen contaminants of potential concern. Screening may be accomplished by using a set of toxicological benchmarks. These benchmarks are helpful in determining whether contaminants warrant further assessment or are at a level that requires no further attention. Unlike exposures to chemicals, which are expressed as the concentration in water or sediment, exposures to radionuclides are expressed as the dose rate received by the organism. The recommended acceptable dose rate to natural populations of aquatic biota is 1 rad d-1. Blaylock, Frank, and O'Neal provide formulas and exposure factors for estimating the dose rates to representative aquatic organisms. Those formulas were used herein to calculate the water and sediment concentrations that result in a total dose rate of 1 rad d-1 to fish for selected radionuclides. These radiological benchmarks are intended for use at the US Department of Energy's (DOE's) Oak Ridge Reservation and at the Portsmouth and Paducah gaseous diffusion plants as screening values only to show the nature and extent of contamination and identify the need for additional site-specific investigation

1998-01-01

340

Microbial degradation of microcystin in Florida's freshwaters.  

UK PubMed Central (United Kingdom)

Presence of microcystin (MC), a predominant freshwater algal toxin and a suspected liver carcinogen, in Florida's freshwaters poses serious health threat to humans and aquatic species. Being recalcitrant to conventional physical and chemical water treatment methods, biological methods of MC removal is widely researched. Water samples collected from five sites of Lake Okeechobee (LO) frequently exposed to toxic Microcystis blooms were used as inoculum for enrichment with microcystin LR (MC-LR) supplied as sole C and N source. After 20 days incubation, MC levels were analyzed using high performance liquid chromatography (HPLC). A bacterial consortium consisting of two isolates DC7 and DC8 from the Indian Prairie Canal sample showed over 74% toxin degradation at the end of day 20. Optimal temperature requirement for biodegradation was identified and phosphorus levels did not affect the MC biodegradation. Based on 16S rRNA sequence similarity the isolate DC8 was found to have a match with Microbacterium sp. and the DC7 isolate with Rhizobium gallicum (AY972457).

Ramani A; Rein K; Shetty KG; Jayachandran K

2012-02-01

 
 
 
 
341

Reclaiming freshwater sustainability in the Cadillac Desert.  

UK PubMed Central (United Kingdom)

Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.

Sabo JL; Sinha T; Bowling LC; Schoups GH; Wallender WW; Campana ME; Cherkauer KA; Fuller PL; Graf WL; Hopmans JW; Kominoski JS; Taylor C; Trimble SW; Webb RH; Wohl EE

2010-12-01

342

Persistence of environmental DNA in freshwater ecosystems.  

UK PubMed Central (United Kingdom)

The precise knowledge of species distribution is a key step in conservation biology. However, species detection can be extremely difficult in many environments, specific life stages and in populations at very low density. The aim of this study was to improve the knowledge on DNA persistence in water in order to confirm the presence of the focus species in freshwater ecosystems. Aquatic vertebrates (fish: Siberian sturgeon and amphibian: Bullfrog tadpoles) were used as target species. In control conditions (tanks) and in the field (ponds), the DNA detectability decreases with time after the removal of the species source of DNA. DNA was detectable for less than one month in both conditions. The density of individuals also influences the dynamics of DNA detectability in water samples. The dynamics of detectability reflects the persistence of DNA fragments in freshwater ecosystems. The short time persistence of detectable amounts of DNA opens perspectives in conservation biology, by allowing access to the presence or absence of species e.g. rare, secretive, potentially invasive, or at low density. This knowledge of DNA persistence will greatly influence planning of biodiversity inventories and biosecurity surveys.

Dejean T; Valentini A; Duparc A; Pellier-Cuit S; Pompanon F; Taberlet P; Miaud C

2011-01-01

343

Persistence of environmental DNA in freshwater ecosystems.  

Science.gov (United States)

The precise knowledge of species distribution is a key step in conservation biology. However, species detection can be extremely difficult in many environments, specific life stages and in populations at very low density. The aim of this study was to improve the knowledge on DNA persistence in water in order to confirm the presence of the focus species in freshwater ecosystems. Aquatic vertebrates (fish: Siberian sturgeon and amphibian: Bullfrog tadpoles) were used as target species. In control conditions (tanks) and in the field (ponds), the DNA detectability decreases with time after the removal of the species source of DNA. DNA was detectable for less than one month in both conditions. The density of individuals also influences the dynamics of DNA detectability in water samples. The dynamics of detectability reflects the persistence of DNA fragments in freshwater ecosystems. The short time persistence of detectable amounts of DNA opens perspectives in conservation biology, by allowing access to the presence or absence of species e.g. rare, secretive, potentially invasive, or at low density. This knowledge of DNA persistence will greatly influence planning of biodiversity inventories and biosecurity surveys. PMID:21858099

Dejean, Tony; Valentini, Alice; Duparc, Antoine; Pellier-Cuit, Stéphanie; Pompanon, François; Taberlet, Pierre; Miaud, Claude

2011-08-08

344

Monitoring endangered freshwater biodiversity using environmental DNA.  

UK PubMed Central (United Kingdom)

Freshwater ecosystems are among the most endangered habitats on Earth, with thousands of animal species known to be threatened or already extinct. Reliable monitoring of threatened organisms is crucial for data-driven conservation actions but remains a challenge owing to nonstandardized methods that depend on practical and taxonomic expertise, which is rapidly declining. Here, we show that a diversity of rare and threatened freshwater animals--representing amphibians, fish, mammals, insects and crustaceans--can be detected and quantified based on DNA obtained directly from small water samples of lakes, ponds and streams. We successfully validate our findings in a controlled mesocosm experiment and show that DNA becomes undetectable within 2?weeks after removal of animals, indicating that DNA traces are near contemporary with presence of the species. We further demonstrate that entire faunas of amphibians and fish can be detected by high-throughput sequencing of DNA extracted from pond water. Our findings underpin the ubiquitous nature of DNA traces in the environment and establish environmental DNA as a tool for monitoring rare and threatened species across a wide range of taxonomic groups.

Thomsen PF; Kielgast J; Iversen LL; Wiuf C; Rasmussen M; Gilbert MT; Orlando L; Willerslev E

2012-06-01

345

Monitoring endangered freshwater biodiversity using environmental DNA.  

Science.gov (United States)

Freshwater ecosystems are among the most endangered habitats on Earth, with thousands of animal species known to be threatened or already extinct. Reliable monitoring of threatened organisms is crucial for data-driven conservation actions but remains a challenge owing to nonstandardized methods that depend on practical and taxonomic expertise, which is rapidly declining. Here, we show that a diversity of rare and threatened freshwater animals--representing amphibians, fish, mammals, insects and crustaceans--can be detected and quantified based on DNA obtained directly from small water samples of lakes, ponds and streams. We successfully validate our findings in a controlled mesocosm experiment and show that DNA becomes undetectable within 2?weeks after removal of animals, indicating that DNA traces are near contemporary with presence of the species. We further demonstrate that entire faunas of amphibians and fish can be detected by high-throughput sequencing of DNA extracted from pond water. Our findings underpin the ubiquitous nature of DNA traces in the environment and establish environmental DNA as a tool for monitoring rare and threatened species across a wide range of taxonomic groups. PMID:22151771

Thomsen, Philip Francis; Kielgast, Jos; Iversen, Lars L; Wiuf, Carsten; Rasmussen, Morten; Gilbert, M Thomas P; Orlando, Ludovic; Willerslev, Eske

2011-12-13

346

Monitoring endangered freshwater biodiversity using environmental DNA  

DEFF Research Database (Denmark)

Freshwater ecosystems are among the most endangered habitats on Earth, with thousands of animal species known to be threatened or already extinct. Reliable monitoring of threatened organisms is crucial for data-driven conservation actions but remains a challenge owing to nonstandardized methods that depend on practical and taxonomic expertise, which is rapidly declining. Here, we show that a diversity of rare and threatened freshwater animals-representing amphibians, fish, mammals, insects and crustaceans-can be detected and quantified based on DNA obtained directly from small water samples of lakes, ponds and streams. We successfully validate our findings in a controlled mesocosm experiment and show that DNA becomes undetectable within 2 weeks after removal of animals, indicating that DNA traces are near contemporary with presence of the species. We further demonstrate that entire faunas of amphibians and fish can be detected by high-throughput sequencing of DNA extracted from pond water. Our findings underpin the ubiquitous nature of DNA traces in the environment and establish environmental DNA as a tool for monitoring rare and threatened species across a wide range of taxonomic groups.

Thomsen, Philip Francis; Kielgast, Jos

2012-01-01

347

Freshwater Biodiversity and Aquatic Insect Diversification.  

UK PubMed Central (United Kingdom)

Inland waters cover less than 1% of Earth's surface but harbor more than 6% of all insect species: Nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are highly susceptible to environmental change and exhibit marked ecological gradients. Standing waters appear to harbor more dispersive species than running waters, but there is little understanding of how this fundamental ecological difference has affected diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bioindicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification. Expected final online publication date for the Annual Review of Entomology Volume 59 is January 07, 2014. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.

Dijkstra KD; Monaghan MT; Pauls SU

2013-10-01

348

The ‘great transformation’ and the cultural biota of populations in movement  

Directory of Open Access Journals (Sweden)

Full Text Available Colonial chroniclers, and later historians, noticed that since colonial times, the “Brazilian being” is a man on the move. They lived on the roads like ants, one said. A society in movement, said another. Until 1850, hundreds of thousands had been forced to cross the South Atlantic. Between the mid-19th century and the first decades of the 20th century, millions crossed the Atlantic; thousands migrated by force from the north to the southeast during the boom in coffee crops. Between 1930 and 1950, hundreds of thousands moved to Paraná. During the 1940s and 50s, thousands more were forced to walk from the northeast to the southeast due to the climate. Between 1960 and 1980, nearly 40 million Brazilians moved from the countryside to the cities and from small towns to large cities, from the south/southeast to the center-north and north. These are populations in movement through space. In each movement, these populations take with them their cultural biota and cause changes to the destination biome, changing its frontiers. The territory where were live today consists of layers upon layers of landscapes built by these populations in movement through space. Plants, animals, insects, germs, techniques and memories are documents of this process that originated our cities. A hundred years ago, it was wilderness; it has been transformed into the landscape of soybean/wheat/sugarcane. Coffee came from Ethiopia, soybeans from China, wheat from Asia, and sugarcane from India. The viruses to be combated were malaria, yellow fever, impaludism. They were stationary viruses. Nowadays, viruses literally fly along with populations. The field of history can no longer renounce the dialogue between space, populations and time.Los cronistas coloniales y, más tarde, los historiadores, notaron que desde el período colonial el “ser brasileño” equivalía a un hombre en desplazamiento. Vivían en los caminos como hormigas, afirmaba uno de ellos. Sociedad en movimiento, decía otro. Hasta 1850, centenas de miles habían sido forzados a cruzar el Atlántico Sur. Entre mediados del siglo XIX y las primeras décadas del XX, millones atravesaron el Océano. Miles fueron obligados a migrar del norte al sureste durante la expansión del cultivo de café. Entre 1930 y 1950, centenas de miles se desplazaron al Estado de Paraná. En las décadas de ’40 y ’50, nuevos grupos fueron empujados a caminar del nordeste al sureste como consecuencia del clima. Entre 1960 y 1980, cerca de 40 millones de brasileños migraron del campo a la ciudad, de las ciudades pequeñas a las grandes, del sursureste a la región centro-oeste y norte. Son poblaciones en movimiento dentro del espacio. En cada desplazamiento, estas poblaciones llevaron consigo su biota cultural, provocando alteraciones en el bioma de destino, transformando las fronteras. El territorio donde vivimos hoy está constituido por camadas y camadas de paisajes construidos por estas poblaciones en movimiento por el espacio. Plantas, animales, insectos, gérmenes, técnicas y memorias son documentos de este proceso que dio origen a nuestras ciudades. Hace cien años existía el sertão brasileño, que se transformó en territorio de cultivo de café y de las pequeñas ciudades; hoy, ese mismo paisaje pasó a ser el paisaje de soja-trigo-caña de azúcar. El café proviene de Etiopía, la soja de China, el trigo de Asia y la caña de azúcar de la India. Los virus a ser enfrentados eran malaria, fiebre amarilla, paludismo. Eran virus estacionales. Literalmente, hoy los virus viajan junto con las poblaciones. El campo de la historia no puede prescindir más del diálogo entre el espacio, las poblaciones y el tiempo.Os cronistas coloniais e, depois, os historiadores, notaram que desde a colônia o “ser brasileiro” é

Gilmar Arruda

2011-01-01

349

Radiation-induced bystander effects: Relevance for radiation protection of human and non-human biota  

International Nuclear Information System (INIS)

In this paper our current knowledge of the mechanisms underlying the induction of bystander effects by low dose low LET ionizing radiation is reviewed in the context of relevance to radiation protection issues. The question of how bystander effects may be related to observed adaptive responses, systemic genomic instability or other effects of low doses exposures is also considered. Bystander effects appear to be the result of a generalized stress response in tissues or cells. The signals may be produced by all exposed cells, but the response may require additional system parameters to exist in order to be expressed. The major response involving low LET radiation exposure discussed in the existing literature is a death response. This can manifest as apoptotic cell death, terminal differentiation, reproductive cell death or necrosis. While a death response might appear to be adverse, the position is argued in this paper, that it can in fact be protective and remove damaged cells from the reproducing population. Since many cell populations carry damaged cells without being exposed to radiation (so-called 'background damage'), it is possible that low dose radiation exposures cause removal of cells damaged by agents other than the test dose of radiation. This mechanism would lead to the production of 'u- or n-shaped' dose response curves. In this scenario, the level of harmful or beneficial response will be related to the background damage carried by the cell population and the genetic program determining response to damage. This model--may be particularly important when attempting to predict the consequences of mixed exposures involving radiation and other environmental stressors on biota. (author)

2005-01-01

350

Adaptative Response and Bystander Effects in Human and Non-Human Biota  

International Nuclear Information System (INIS)

Recent advances in our understanding of effects of radiation on living cells suggests that fundamentally different mechanisms are operating at low doses compared with high doses. Also, acute low doses appear to involve different response mechanisms compared with chronic low dose. Both genomic instability and so called bystander effects show many similarities with well known cellular responses to oxidative stress. These predominate following low dose exposures and are maximally expressed at doses as low as 5mGy. At the biological level this is not surprising. Chemical toxicity has been known for many years to show these patterns of dose response. Cell signaling and coordinated stress mechanisms appear to dominate acute low dose exposure to chemicals. Adaptation to chemical exposures is also well documented although mechanisms of adaptive responses are less clear. In the radiation field adaptive responses also become important when low doses are protracted or fractionated. Recent data from our group concerning bystander effects following multiple low dose exposure suggest that adaptive responses can be induced in cells which only receive signals from irradiated neighbours. We have determined using genetically distinct mice, with different radiosensitivities, that bystander effects occur in vivo and vary according to genetic background. We also have data showing delayed and bystander effects in fish and in prawns following in vitro irradiation of haematopoietic tissue. These data have implications for environmental radiation protection of human and non human species alike. Simple extrapolations from high to low dose exposure may need to be re evaluated. This paper discusses our knowledge about these low dose radiobiological effects in both human and non-human biota and draws attention to the problem of defining the important questions relevant for the level of biological organisation being studied. (Author)

2004-01-01

351

Comparing measured and predicted PCB concentrations in Arctic seawater and marine biota  

Energy Technology Data Exchange (ETDEWEB)

When a mechanistic food web model was parameterized for the Arctic marine ecosystem, it predicted PCB concentrations in zooplankton and fish that were two orders of magnitude lower than measured. PCB concentrations measured in zooplankton and fish were within the laboratory's accredited quality assured criteria, and were comparable to other Arctic regions. Although on a different scale, the predicted and measured PCB concentrations were highly correlated. As sensitivity analyses indicated water concentrations as the most sensitive parameter for the model output, dissolved water concentrations were predicted using measured zooplankton and air PCB concentrations, and empirical and mechanistic models. The food web model and the empirical relationship between bioaccumulation factor and octanol-water partitioning coefficient predicted mean dissolved water concentrations of 28 and 29 pg/L {sigma}PCB{sub 6} (PCB-28, -52, -105, -118, -138, -153), respectively. Mean dissolved water concentration predicted from measured air concentrations in 1996 was 7.6 pg/L {sigma}PCB{sub 5} (PCB-28 was not analysed). Mean dissolved water concentration measured in Barents Sea water sampled simultaneously as the biota in 1999 was 0.3 pg/L {sigma}PCB{sub 6}. The dissolved water concentrations predicted from zooplankton PCB concentrations were comparable to water concentrations measured in 1996, whereas the dissolved water concentrations measured in 1999 were comparable to measurements from 2001. If the present high empirically derived bioaccumulation factors (log BAF 7.3-9.0) were realistic, this suggests that bioaccumulation in Arctic zooplankton is more efficient that previously assumed. The present study illustrates and discusses some of the difficulties encountered when different approaches to study environmental distribution of contaminants are compared.

Borga, Katrine [Environmental Modelling Group, Department of Structural and Functional Biology, University of Insubria, Via Dunant 3, 21100 Varese (Italy) and Norwegian Polar Institute, Polar Environmental Centre, N-9296 Tromso (Norway)]. E-mail: katrine.borga@npolar.no; Di Guardo, Antonio [Environmental Modelling Group, Department of Structural and Functional Biology, University of Insubria, Via Dunant 3, 21100 Varese (Italy)

2005-04-15

352

Enhancement of tritium concentrations on uptake by marine biota: experience from UK coastal waters  

Energy Technology Data Exchange (ETDEWEB)

Concentrations of tritium in sea water and marine biota as reported over the last {approx} 10 years from monitoring programmes carried out by this laboratory under contract to the UK Food Standards Agency are reviewed from three areas: near Cardiff; Sellafield; and Hartlepool. Near Cardiff, enhancement of concentration factors (CFs) above an a priori value of {approx} 1 have already been studied, and attributed to compounds containing organically bound tritium in local radioactive waste discharges. Further data for Cardiff up to 2006 are reported in this note. Up to 2001, CFs increased to values of more than {approx} 7000 in flounders and {approx} 4000 in mussels, but have subsequently reduced; this variability could be due to changes in the organic constitution of compounds discharged. Near Sellafield and Hartlepool, enhancements to the tritium concentration factor are observed but they are relatively small compared with those near Cardiff. Near Sellafield, plaice and mussels appear to have a CF for tritium of {approx} 10; in some cases concentrations of tritium in winkles are below detection limits and positively measured values indicate a CF of {approx} 3. The variation could be due to mechanisms of uptake by the different organisms. Near Hartlepool there were only a few cases where tritium was positively measured. These data give a value of {approx} 5 for the CF in plaice (on the basis of two samples); {approx} 15 in winkles (eight samples); and > 45 in mussels (two samples). Any differences between the behaviours at Sellafield and Hartlepool would need to be confirmed by improved measurements. Possible causes are the organic composition of the effluent and differences in environmental behaviour and uptake by organisms near the two sites. These potential causes need further investigation. It is emphasised that results from tritium analyses are heavily method dependent; thus comparison with results from other programmes needs to take this into account. Further, the results for enhancement of CF will also depend on the definition of CF itself. (note)

Hunt, G J; Bailey, T A; Jenkinson, S B; Leonard, K S [Centre for Environment, Fisheries and Aquaculture Science, Lowestoft NR33 0HT (United Kingdom)

2010-03-01

353

Properties and structure of peat humic acids depending on humification and precursor biota in bogs  

Science.gov (United States)

Humic substances form most of the organic component of soil, peat and natural waters, but their structure and properties very much differs depending on their source. The aim of this study is to characterize humic acids from raised bog peat profiles to evaluate the homogeneity of humic acids isolated from the bog bodies and study peat humification impact on properties of humic acids. A major impact on the structure of peat humic acids have raised bog biota (dominantly represented by bryophytes of different origin) void of lignin. For characterization of peat humic acids their elemental (CHNOS), functional (-COOH, phenolic OH) analysis, spectroscopic characterization (UV, fluorescence, FTIR, 1H NMR, CP/MAS 13C NMR, ESR) and degradation studies (Py-GC/MS) were done. Peat humic acids (HA) have an intermediate position between the living organic matter and coal organic matter and their structure is formed in a process in which more labile structures (carbohydrates, amino acids, etc.) are destroyed, but thermodynamically more stable aromatic and polyaromatic structures emerge. Comparatively, the studied peat HAs are at the start of the transformation process of living organic matter. Concentrations of carboxyl and phenolic hydroxyl groups changes depending on the depth of peat from which HAs have been isolated: and carboxylic acidity is increasing with depth of peat location and the humification degree. The ability to influence the surface tension of peat humic acids isolated from a well-characterized bog profile demonstrates dependence on age and humification degree. With increase of the humification degree and age of humic acids, their molecular complexity and ability to influence surface tension decreases; even so, the impact of the biological precursor (peat-forming bryophytes and plants) can be identified.

Klavins, Maris; Purmalis, Oskars

2013-04-01

354

Chemical analysis and genotoxicity of high molecular mass PAH in sediment samples and biota  

International Nuclear Information System (INIS)

A normal phase liquid chromatography (NPLC) method was used to fractionate the organic extracts of prepared from coal tar-contaminated sediments from hamilton Harbor in Ontario and from Sydney Harbor in Nova Scotia into molecular mass classes. Each PAH fraction up to 302 amu was analyzed by GC-MS and fractions containing PAH with molecular masses greater than 302 amu were analyzed by atmospheric pressure chemical ionization (APCI) LC-MS.Each fraction was also subjected to Ames bioassays using a TA100-like strain of Salmonella typhimurium (YG1025 + S9). The 300/302 amu, 326/328 and 350/352 amu PAH fractions accounted for 25% of the total genotoxic response of the extract; these PAH constitute a substantial genotoxic burden. A number of 300, 302, 326, 350, 374 and 400 amu PAH were identified using APCI LC-MS and comparison with authentic standards. The non-polar aromatic extracts of bottom sediments, suspended sediments and zebra mussels from Hamilton Harbor were also examined by GC-MS, APCI LC-MS and genotoxicity bioassays. The profiles of the priority and high mass PAH in these samples were identical showing that all PAH up to and exceeding 400 amu were readily bioavailable to biota such as Zebra mussels. In addition, the pseudo faeces of the Zebra mussels and amphipod detritivores which fed on the pseudo faeces had chemical profiles identical to the Zebra mussels. Since many sport fish prize amphipods as food, this observation demonstrates a pathway for organic contaminants adsorbed to suspended sediments to enter the food chain of non-bottom-feeding fish in areas infested by Zebra mussels.

1995-01-01

355

Chemical analysis and genotoxicity of high molecular mass PAH in sediment samples and biota  

Energy Technology Data Exchange (ETDEWEB)

A normal phase liquid chromatography (NPLC) method was used to fractionate the organic extracts of prepared from coal tar-contaminated sediments from hamilton Harbor in Ontario and from Sydney Harbor in Nova Scotia into molecular mass classes. Each PAH fraction up to 302 amu was analyzed by GC-MS and fractions containing PAH with molecular masses greater than 302 amu were analyzed by atmospheric pressure chemical ionization (APCI) LC-MS.Each fraction was also subjected to Ames bioassays using a TA100-like strain of Salmonella typhimurium (YG1025 + S9). The 300/302 amu, 326/328 and 350/352 amu PAH fractions accounted for 25% of the total genotoxic response of the extract; these PAH constitute a substantial genotoxic burden. A number of 300, 302, 326, 350, 374 and 400 amu PAH were identified using APCI LC-MS and comparison with authentic standards. The non-polar aromatic extracts of bottom sediments, suspended sediments and zebra mussels from Hamilton Harbor were also examined by GC-MS, APCI LC-MS and genotoxicity bioassays. The profiles of the priority and high mass PAH in these samples were identical showing that all PAH up to and exceeding 400 amu were readily bioavailable to biota such as Zebra mussels. In addition, the pseudo faeces of the Zebra mussels and amphipod detritivores which fed on the pseudo faeces had chemical profiles identical to the Zebra mussels. Since many sport fish prize amphipods as food, this observation demonstrates a pathway for organic contaminants adsorbed to suspended sediments to enter the food chain of non-bottom-feeding fish in areas infested by Zebra mussels.

McCarry, B.E.; Marvin, C.H.; Smith, R.W.; Bryant, D.W. [McMaster Univ., Hamilton, Ontario (Canada)

1995-12-31

356

Radionuclides in the adriatic sea and related dose-rate assessment for marine biota.  

UK PubMed Central (United Kingdom)

Artificial and natural radionuclides were determined in the Adriatic Sea in the seawater and sediment samples in the period from 2007 to 2011. The sampling areas were coastal waters of Slovenia, Croatia and Albania, together with the deepest part of the Adriatic in South Adriatic Pit and Otranto strait. Sampling locations were chosen to take into account all major geological and geographical features of this part of the Adriatic Sea and possible coastal influences. After initial sample preparation steps, samples were measured by gamma-ray spectrometry. In the seawater ??K activity concentrations were in the range from 6063 to 10519 Bq m?³, ¹³?Cs from 1.6 to 3.8 Bq m?³, ²²?Ra from 23 to 31 Bq m?³, ²²?Ra from 1 to 25 Bq m?³ and ²³?U from 64 to 490 Bq m?³. The results of sediment samples showed that ??K was in the range from 87 to 593 Bq kg?¹, ¹³?Cs from 0.8 to 7.3 Bq kg?¹, ²²?Ra from 18 to 35 Bq kg?¹, ²²?Ra from 4 to 29 Bq kg?¹ and ²³?U from 14 to 120 Bq kg?¹. In addition, the ERICA Assessment Tool was used for the assessment of dose rates for reference marine organisms using the activity concentrations of the determined radionuclides in seawater. The assessment showed that for the most of the organisms, the dose rates were within the background levels, indicating that the determined values for seawater does not pose a significant risk for the most of marine biota. In the study, the results are critically discussed and compared with other similar studies worldwide. Generally, the activity concentrations of the examined radionuclides did not differ from those reported for the rest of the Mediterranean Sea.

Petrinec B; Strok M; Franic Z; Smodis B; Pavicic-Hamer D

2013-01-01

357

Responses of Freshwater Plants and Invertebrates to Acidification.  

Science.gov (United States)

Acidic, oligotrophic, clear waters often have strong similarities among their biota. In the phytoplankton, Dinophyceae, and to a lesser extent Chrysophyceae tend to dominate. Production of 25 Canadian Shield lakes (pH 6.1-7.1) ranged from 25 to 240 mg C m...

G. R. Hendrey N. D. Yan K. J. Baumgartner

1980-01-01