A re-evaluation of PETROTOX for predicting acute and chronic toxicity of petroleum substances.

Science.gov (United States)

Redman, Aaron D; Parkerton, Thomas F; Leon Paumen, Miriam; Butler, Josh D; Letinski, Daniel J; den Haan, Klass

2017-08-01

The PETROTOX model was developed to perform aquatic hazard assessment of petroleum substances based on substance composition. The model relies on the hydrocarbon block method, which is widely used for conducting petroleum substance risk assessments providing further justification for evaluating model performance. Previous work described this model and provided a preliminary calibration and validation using acute toxicity data for limited petroleum substance. The objective of the present study was to re-evaluate PETROTOX using expanded data covering both acute and chronic toxicity endpoints on invertebrates, algae, and fish for a wider range of petroleum substances. The results indicated that recalibration of 2 model parameters was required, namely, the algal critical target lipid body burden and the log octanol-water partition coefficient (K OW ) limit, used to account for reduced bioavailability of hydrophobic constituents. Acute predictions from the updated model were compared with observed toxicity data and found to generally be within a factor of 3 for algae and invertebrates but overestimated fish toxicity. Chronic predictions were generally within a factor of 5 of empirical data. Furthermore, PETROTOX predicted acute and chronic hazard classifications that were consistent or conservative in 93 and 84% of comparisons, respectively. The PETROTOX model is considered suitable for the purpose of characterizing petroleum substance hazard in substance classification and risk assessments. Environ Toxicol Chem 2017;36:2245-2252. © 2017 SETAC. © 2017 SETAC.

A scheme for regulating toxic substances to water quality of Chamsil upstream water system

Energy Technology Data Exchange (ETDEWEB)

Kim, Kang Suk; Kim, Jee Hoon [Korea Environment Institute, Seoul (Korea)

1998-12-01

This study asserts to reflect a concept of toxicity thoroughly in the present water quality concept. It presents an appropriate solution to control toxic substances flowing into the Chamsil upstream water system. Although a regulation of toxic substances into major rivers in Korea other than Han river is also required urgently, it will be studied in future. It is expected that this study on Chamsil upstream would be a cornerstone for establishing a national regulation policy of toxic substances into water system. 28 refs., 1 fig., 36 tabs.

Effects of water quality parameters on boron toxicity to Ceriodaphnia dubia.

Science.gov (United States)

Dethloff, Gail M; Stubblefield, William A; Schlekat, Christian E

2009-07-01

The potential modifying effects of certain water quality parameters (e.g., hardness, alkalinity, pH) on the acute toxicity of boron were tested using a freshwater cladoceran, Ceriodaphnia dubia. By comparison, boron acute toxicity was less affected by water quality characteristics than some metals (e.g., copper and silver). Increases in alkalinity over the range tested did not alter toxicity. Increases in water hardness appeared to have an effect with very hard waters (>500 mg/L as CaCO(3)). Decreased pH had a limited influence on boron acute toxicity in laboratory waters. Increasing chloride concentration did not provide a protective effect. Boron acute toxicity was unaffected by sodium concentrations. Median acute lethal concentrations (LC(50)) in natural water samples collected from three field sites were all greater than in reconstituted laboratory waters that matched natural waters in all respects except for dissolved organic carbon. Water effect ratios in these waters ranged from 1.4 to 1.8. In subsequent studies using a commercially available source of natural organic matter, acute toxicity decreased with increased dissolved organic carbon, suggesting, along with the natural water studies, that dissolved organic carbon should be considered further as a modifier of boron toxicity in natural waters where it exceeds 2 mg/L.

An assessment of whole effluent toxicity testing as a means of regulating waters produced by the oil and gas industry

International Nuclear Information System (INIS)

Hill, S.L.; Bergman, H.L.

1993-01-01

Approximately 500 million barrels of produced water are discharged to Wyoming's surface waters by the oil and gas industry. This discharges are of two types: direct and indirect. The direct discharges have been issued NPDES permits requiring whole effluent toxicity testing. Toxicity testing requirements have not been incorporated into permits written for indirect discharges because of the applicability of toxicity testing for regulating these waters has not been determined. Preliminary testing has shown that most produced waters are toxic at the point of discharge because of high concentrations of hydrogen sulfide, but that the toxicity of an indirect discharge is often lost before it reaches a receiving stream. Thus, whole effluent toxicity testing of an indirect discharge may be overly stringent, resulting in treatment or reinjection of the water or closure of the well. Any of these options would have severe economic consequences for oil producers and the state's agricultural industry. The purpose of this study was to determine whether whole effluent toxicity testing actually predicts the in-stream effects of indirect discharges on water quality and benthic invertebrate populations. The authors will report the results of short-term ambient toxicity tests and in-stream bioassessments performed upstream and downstream of six indirect discharges located in four drainages in Wyoming

Application of TIE's in assessing toxicity associated with oil sands process waters

International Nuclear Information System (INIS)

MacKinnon, M.

1998-01-01

The hot water digestion process which separates bitumen from oil sands produces large volumes of process-affected waters which are extremely toxic to aquatic organisms. At Syncrude Canada's northeastern Alberta plant, the toxic waters are contained on the site and none are discharged. Organic acids, hydrocarbons and salts are leached into the tailings waters. A toxicity identification evaluation (TIE) test was used to confirm the main contributors to the acute toxicity in these waters. A battery bioassay approach as well as field and laboratory testing was used to understand the source, pathway and duration of the toxicity. Bioassays helped in developing ways in which to mitigate toxicity issues in both reclamation and operational waters. It was demonstrated that natural bioremediation of process-affected waters can reduce acute and chronic toxicity. The long term reclamation impacts of these waters has yet to be determined

Prediction of toxic metals concentration using artificial intelligence techniques

Science.gov (United States)

Gholami, R.; Kamkar-Rouhani, A.; Doulati Ardejani, F.; Maleki, Sh.

2011-12-01

Groundwater and soil pollution are noted to be the worst environmental problem related to the mining industry because of the pyrite oxidation, and hence acid mine drainage generation, release and transport of the toxic metals. The aim of this paper is to predict the concentration of Ni and Fe using a robust algorithm named support vector machine (SVM). Comparison of the obtained results of SVM with those of the back-propagation neural network (BPNN) indicates that the SVM can be regarded as a proper algorithm for the prediction of toxic metals concentration due to its relative high correlation coefficient and the associated running time. As a matter of fact, the SVM method has provided a better prediction of the toxic metals Fe and Ni and resulted the running time faster compared with that of the BPNN.

Novel view on predicting acute toxicity: Decomposing toxicity data in species vulnerability and chemical potency.

NARCIS (Netherlands)

Jager, D.T.; Posthuma, L.; Zwart, D.D.; van de Meent, D.

2007-01-01

Chemical risk assessment usually applies empirical methods to predict toxicant effects on different species. We propose a more mechanism-oriented approach, and introduce a method to decompose toxicity data in a contribution from the chemical (potency) and from the exposed species (vulnerability). We

Predictive QSAR modelling of algal toxicity of ionic liquids and its interspecies correlation with Daphnia toxicity.

Science.gov (United States)

Roy, Kunal; Das, Rudra Narayan; Popelier, Paul L A

2015-05-01

Predictive toxicology using chemometric tools can be very useful in order to fill the data gaps for ionic liquids (ILs) with limited available experimental toxicity information, in view of their growing industrial uses. Though originally promoted as green chemicals, ILs have now been shown to possess considerable toxicity against different ecological endpoints. Against this background, quantitative structure-activity relationship (QSAR) models have been developed here for the toxicity of ILs against the green algae Scenedesmus vacuolatus using computed descriptors with definite physicochemical meaning. The final models emerged from E-state indices, extended topochemical atom (ETA) indices and quantum topological molecular similarity (QTMS) indices. The developed partial least squares models support the established mechanism of toxicity of ionic liquids in terms of a surfactant action of cations and chaotropic action of anions. The models have been developed within the guidelines of the Organization of Economic Co-operation and Development (OECD) for regulatory QSAR models, and they have been validated both internally and externally using multiple strategies and also tested for applicability domain. A preliminary attempt has also been made, for the first time, to develop interspecies quantitative toxicity-toxicity relationship (QTTR) models for the algal toxicity of ILs with Daphnia toxicity, which should be interesting while predicting toxicity of ILs for an endpoint when the data for the other are available.

A novel two-dimensional liquid chromatographic system for the online toxicity prediction of pharmaceuticals and related substances

Energy Technology Data Exchange (ETDEWEB)

Li, Jian; Xu, Li [Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030 (China); Shi, Zhi-guo, E-mail: shizg@whu.edu.cn [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu, Min [Hubei Instrument for Food and Drug Control, Wuhan (China)

2015-08-15

Highlights: • A novel two-dimensional liquid chromatographic system was developed. • The 1st dimension was ODS to separate components in the sample. • The 2nd dimension was biopartitioning micellar chromatography to predict toxicity. • The system was used to screen toxicity of pharmaceuticals and related substances. • It was promising for fast online toxicity screening of complex sample in one step. - Abstract: In this study, a novel two-dimensional liquid chromatographic (2D-LC) system was developed for simultaneous separation and toxicity prediction of pharmaceutical and its related substances. A conventional ODS column was used on the 1st-D to separate the sample; while, bio-partitioning micellar chromatography served as the 2nd-D to predict toxicity of the components. The established system was tested for the toxicity of ibuprofen and its impurities with known toxicity. With only one injection, ibuprofen and its impurities were separated on the 1st-D; and LC50 values of individual impurity were obtained based on the quantitative retention–activity relationships, which agreed well with the reported data. Furthermore, LC50 values of photolysis transformation products (TPs) of carprofen, ketoprofen and diclofenac acid (as unknown compounds) were screened in this 2D-LC system, which could be an indicator of the toxicity of these TPs and was meaningful for the environmental monitoring and drinking water treatment. The established 2D-LC system was cost-effective, time-saving and reliable, and was promising for fast online screening of toxicity of known and unknown analytes in the complex sample in a single step. It may find applications in environment, pharmaceutical and food, etc.

A novel two-dimensional liquid chromatographic system for the online toxicity prediction of pharmaceuticals and related substances

International Nuclear Information System (INIS)

Li, Jian; Xu, Li; Shi, Zhi-guo; Hu, Min

2015-01-01

Highlights: • A novel two-dimensional liquid chromatographic system was developed. • The 1st dimension was ODS to separate components in the sample. • The 2nd dimension was biopartitioning micellar chromatography to predict toxicity. • The system was used to screen toxicity of pharmaceuticals and related substances. • It was promising for fast online toxicity screening of complex sample in one step. - Abstract: In this study, a novel two-dimensional liquid chromatographic (2D-LC) system was developed for simultaneous separation and toxicity prediction of pharmaceutical and its related substances. A conventional ODS column was used on the 1st-D to separate the sample; while, bio-partitioning micellar chromatography served as the 2nd-D to predict toxicity of the components. The established system was tested for the toxicity of ibuprofen and its impurities with known toxicity. With only one injection, ibuprofen and its impurities were separated on the 1st-D; and LC50 values of individual impurity were obtained based on the quantitative retention–activity relationships, which agreed well with the reported data. Furthermore, LC50 values of photolysis transformation products (TPs) of carprofen, ketoprofen and diclofenac acid (as unknown compounds) were screened in this 2D-LC system, which could be an indicator of the toxicity of these TPs and was meaningful for the environmental monitoring and drinking water treatment. The established 2D-LC system was cost-effective, time-saving and reliable, and was promising for fast online screening of toxicity of known and unknown analytes in the complex sample in a single step. It may find applications in environment, pharmaceutical and food, etc

Predicting refinery effluent toxicity on the basis of hydrocarbon composition determined by GCxGC analysis

Energy Technology Data Exchange (ETDEWEB)

Whale, G. [and others

2013-04-15

A high resolution analytical method for determining hydrocarbon blocks in petroleum products by comprehensive two-dimensional gas chromatography (GCxGC) was used for the analysis of petroleum hydrocarbons extracted from refinery effluents. From 105 CONCAWE refineries in Europe 111 refinery effluents were collected in the period June 2008 to March 2009 (CONCAWE, 2010). The effluents were analysed for metals, standard effluent parameters (including Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), oil in water (OiW), GCxGC speciated hydrocarbons, BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) and volatile organic compounds. This report describes the subsequent analysis of the GCxGC data, as described in hydrocarbon blocks, and uses the PETROTOX model, to predict the environmental toxicity (i.e. ecotoxicity) of the discharged effluents. A further analysis was undertaken to address the potential environmental impact of these predicted effects initially using default dilution factors and then,when necessary site specific factors. The report describes all the methods used to arrive at the predictions, and shows that for the majority of refinery effluents direct toxicity effects in the effluents are not anticipated. Furthermore, when applying either the EU Risk Assessment Technical Guidance Document (TGD) default dilution factors or site specific dilution factors, none of the refineries are predicted to exerting either acute or chronic toxicity to organisms in the receiving aquatic environment, based on their hydrocarbon composition present in the effluent samples.

Nomogram to predict rectal toxicity following prostate cancer radiotherapy.

Directory of Open Access Journals (Sweden)

Jean-Bernard Delobel

Full Text Available To identify predictors of acute and late rectal toxicity following prostate cancer radiotherapy (RT, while integrating the potential impact of RT technique, dose escalation, and moderate hypofractionation, thus enabling us to generate a nomogram for individual prediction.In total, 972 patients underwent RT for localized prostate cancer, to a total dose of 70 Gy or 80 Gy, using two different fractionations (2 Gy or 2.5 Gy/day, by means of several RT techniques (3D conformal RT [3DCRT], intensity-modulated RT [IMRT], or image-guided RT [IGRT]. Multivariate analyses were performed to identify predictors of acute and late rectal toxicity. A nomogram was generated based on the logistic regression model used to predict the 3-year rectal toxicity risk, with its accuracy assessed by dividing the cohort into training and validation subgroups.Mean follow-up for the entire cohort was 62 months, ranging from 6 to 235. The rate of acute Grade ≥2 rectal toxicity was 22.2%, decreasing when combining IMRT and IGRT, compared to 3DCRT (RR = 0.4, 95%CI: 0.3-0.6, p<0.01. The 5-year Grade ≥2 risks for rectal bleeding, urgency/tenesmus, diarrhea, and fecal incontinence were 9.9%, 4.5%, 2.8%, and 0.4%, respectively. The 3-year Grade ≥2 risk for overall rectal toxicity increased with total dose (p<0.01, RR = 1.1, 95%CI: 1.0-1.1 and dose per fraction (2Gy vs. 2.5Gy (p = 0.03, RR = 3.3, 95%CI: 1.1-10.0, and decreased when combining IMRT and IGRT (RR = 0.50, 95% CI: 0.3-0.8, p<0.01. Based on these three parameters, a nomogram was generated.Dose escalation and moderate hypofractionation increase late rectal toxicity. IMRT combined with IGRT markedly decreases acute and late rectal toxicity. Performing combined IMRT and IGRT can thus be envisaged for dose escalation and moderate hypofractionation. Our nomogram predicts the 3-year rectal toxicity risk by integrating total dose, fraction dose, and RT technique.

Prediction of toxicity and comparison of alternatives using WebTEST (Web-services Toxicity Estimation Software Tool)

Science.gov (United States)

A Java-based web service is being developed within the US EPA’s Chemistry Dashboard to provide real time estimates of toxicity values and physical properties. WebTEST can generate toxicity predictions directly from a simple URL which includes the endpoint, QSAR method, and ...

Physicochemical transformation and algal toxicity of engineered nanoparticles in surface water samples

International Nuclear Information System (INIS)

Zhang, Luqing; Li, Jingyi; Yang, Kun; Liu, Jingfu; Lin, Daohui

2016-01-01

Most studies on the behavior and toxicity of engineered nanoparticles (NPs) have been conducted in artificial water with well-controlled conditions, which are dramatically different from natural waters with complex compositions. To better understand the fate and toxicity of NPs in the natural water environment, physicochemical transformations of four NPs (TiO_2, ZnO, Ag, and carbon nanotubes (CNTs)) and their toxicities towards a unicellular green alga (Chlorella pyrenoidosa) in four fresh water and one seawater sample were investigated. Results indicated that water chemistry had profound effects on aggregation, dissolution, and algal toxicity of the NPs. The strongest homoaggregation of the NPs was associated with the highest ionic strength, but no obvious correlation was observed between the homoaggregation of NPs and pH or dissolved organic matter content of the water samples. The greatest dissolution of ZnO NPs also occurred in seawater with the highest ionic strength, while the dissolution of Ag NPs varied differently from ZnO NPs. The released Zn"2"+ and especially Ag"+ mainly accounted for the algal toxicity of ZnO and Ag NPs, respectively. The NP-cell heteroagglomeration occurred generally for CNTs and Ag NPs, which contributed to the observed nanotoxicity. However, there was no significant correlation between the observed nanotoxicity and the type of NP or the water chemistry. It was thus concluded that the physicochemical transformations and algal toxicities of NPs in the natural water samples were caused by the combined effects of complex water quality parameters rather than any single influencing factor alone. These results will increase our knowledge on the fate and effects of NPs in the aquatic environment. - Highlights: • Transformation and algal toxicity of four NPs in five surface water samples were studied. • The transformation and toxicity were dependent on the types of NPs and water samples. • No single water parameter alone was

Predictive acute toxicity tests with pesticides.

Science.gov (United States)

Brown, V K

1983-01-01

By definition pesticides are biocidal products and this implies a probability that pesticides may be acutely toxic to species other than the designated target species. The ways in which pesticides are manufactured, formulated, packaged, distributed and used necessitates a potential for the exposure of non-target species although the technology exists to minimize adventitious exposure. The occurrence of deliberate exposure of non-target species due to the misuse of pesticides is known to happen. The array of predictive acute toxicity tests carried out on pesticides and involving the use of laboratory animals can be justified as providing data on which hazard assessment can be based. This paper addresses the justification and rationale of this statement.

Predicting toxic heavy metal movements in upper Sanyati catchment ...

African Journals Online (AJOL)

Water samples from boreholes located in areas where mining, mineral processing and agricultural activities were dominant, yielded the highest values of toxic heavy metals. Dilution Attenuation Factor (DAF) for each toxic heavy metal was calculated to observe metal behaviour along the contaminant path for each season.

Toxicological relationships between proteins obtained from protein target predictions of large toxicity databases

International Nuclear Information System (INIS)

Nigsch, Florian; Mitchell, John B.O.

2008-01-01

The combination of models for protein target prediction with large databases containing toxicological information for individual molecules allows the derivation of 'toxiclogical' profiles, i.e., to what extent are molecules of known toxicity predicted to interact with a set of protein targets. To predict protein targets of drug-like and toxic molecules, we built a computational multiclass model using the Winnow algorithm based on a dataset of protein targets derived from the MDL Drug Data Report. A 15-fold Monte Carlo cross-validation using 50% of each class for training, and the remaining 50% for testing, provided an assessment of the accuracy of that model. We retained the 3 top-ranking predictions and found that in 82% of all cases the correct target was predicted within these three predictions. The first prediction was the correct one in almost 70% of cases. A model built on the whole protein target dataset was then used to predict the protein targets for 150 000 molecules from the MDL Toxicity Database. We analysed the frequency of the predictions across the panel of protein targets for experimentally determined toxicity classes of all molecules. This allowed us to identify clusters of proteins related by their toxicological profiles, as well as toxicities that are related. Literature-based evidence is provided for some specific clusters to show the relevance of the relationships identified

Toxicity profile of labile preservative bronopol in water: The role of more persistent and toxic transformation products

International Nuclear Information System (INIS)

Cui Na; Zhang Xiaoxiang; Xie Qing; Wang Se; Chen Jingwen; Huang Liping; Qiao Xianliang; Li Xuehua; Cai Xiyun

2011-01-01

Transformation products usually differ in environmental behaviors and toxicological properties from the parent contaminants, and probably cause potential risks to the environment. Toxicity evolution of a labile preservative, bronopol, upon primary aquatic degradation processes was investigated. Bronopol rapidly hydrolyzed in natural waters, and primarily produced more stable 2-bromo-2-nitroethanol (BNE) and bromonitromethane (BNM). Light enhanced degradation of the targeted compounds with water site specific photoactivity. The bond order analysis theoretically revealed that the reversible retroaldol reactions were primary degradation routes for bronopol and BNE. Judging from toxicity assays and the relative pesticide toxicity index, these degradation products (i.e., BNE and BNM), more persistent and higher toxic than the parent, probably accumulated in natural waters and resulted in higher or prolonging adverse impacts. Therefore, these transformation products should be included into the assessment of ecological risks of non-persistent and low toxic chemicals such as the preservative bronopol. - The preservative bronopol is non-persistent and low toxic, but some transformation products can cause higher or prolonging adverse impacts.

Toxicity profile of labile preservative bronopol in water: The role of more persistent and toxic transformation products

Energy Technology Data Exchange (ETDEWEB)

Cui Na; Zhang Xiaoxiang; Xie Qing; Wang Se; Chen Jingwen; Huang Liping; Qiao Xianliang; Li Xuehua [Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Cai Xiyun, E-mail: xiyuncai@dlut.edu.c [Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China)

2011-02-15

Transformation products usually differ in environmental behaviors and toxicological properties from the parent contaminants, and probably cause potential risks to the environment. Toxicity evolution of a labile preservative, bronopol, upon primary aquatic degradation processes was investigated. Bronopol rapidly hydrolyzed in natural waters, and primarily produced more stable 2-bromo-2-nitroethanol (BNE) and bromonitromethane (BNM). Light enhanced degradation of the targeted compounds with water site specific photoactivity. The bond order analysis theoretically revealed that the reversible retroaldol reactions were primary degradation routes for bronopol and BNE. Judging from toxicity assays and the relative pesticide toxicity index, these degradation products (i.e., BNE and BNM), more persistent and higher toxic than the parent, probably accumulated in natural waters and resulted in higher or prolonging adverse impacts. Therefore, these transformation products should be included into the assessment of ecological risks of non-persistent and low toxic chemicals such as the preservative bronopol. - The preservative bronopol is non-persistent and low toxic, but some transformation products can cause higher or prolonging adverse impacts.

Bioluminescent bioreporter pad biosensor for monitoring water toxicity.

Science.gov (United States)

Axelrod, Tim; Eltzov, Evgeni; Marks, Robert S

2016-01-01

Toxicants in water sources are of concern. We developed a tool that is affordable and easy-to-use for monitoring toxicity in water. It is a biosensor composed of disposable bioreporter pads (calcium alginate matrix with immobilized bacteria) and a non-disposable CMOS photodetector. Various parameters to enhance the sensor's signal have been tested, including the effect of alginate and bacterium concentrations. The effect of various toxicants, as well as, environmental samples were tested by evaluating their effect on bacterial luminescence. This is the first step in the creation of a sensitive and simple operative tool that may be used in different environments. Copyright © 2015 Elsevier B.V. All rights reserved.

Using quantitative structure-activity relationships (QSAR) to predict toxic endpoints for polycyclic aromatic hydrocarbons (PAH).

Science.gov (United States)

Bruce, Erica D; Autenrieth, Robin L; Burghardt, Robert C; Donnelly, K C; McDonald, Thomas J

2008-01-01

Quantitative structure-activity relationships (QSAR) offer a reliable, cost-effective alternative to the time, money, and animal lives necessary to determine chemical toxicity by traditional methods. Additionally, humans are exposed to tens of thousands of chemicals in their lifetimes, necessitating the determination of chemical toxicity and screening for those posing the greatest risk to human health. This study developed models to predict toxic endpoints for three bioassays specific to several stages of carcinogenesis. The ethoxyresorufin O-deethylase assay (EROD), the Salmonella/microsome assay, and a gap junction intercellular communication (GJIC) assay were chosen for their ability to measure toxic endpoints specific to activation-, induction-, and promotion-related effects of polycyclic aromatic hydrocarbons (PAH). Shape-electronic, spatial, information content, and topological descriptors proved to be important descriptors in predicting the toxicity of PAH in these bioassays. Bioassay-based toxic equivalency factors (TEF(B)) were developed for several PAH using the quantitative structure-toxicity relationships (QSTR) developed. Predicting toxicity for a specific PAH compound, such as a bioassay-based potential potency (PP(B)) or a TEF(B), is possible by combining the predicted behavior from the QSTR models. These toxicity estimates may then be incorporated into a risk assessment for compounds that lack toxicity data. Accurate toxicity predictions are made by examining each type of endpoint important to the process of carcinogenicity, and a clearer understanding between composition and toxicity can be obtained.

Random Forests to Predict Rectal Toxicity Following Prostate Cancer Radiation Therapy

International Nuclear Information System (INIS)

Ospina, Juan D.; Zhu, Jian; Chira, Ciprian; Bossi, Alberto; Delobel, Jean B.; Beckendorf, Véronique; Dubray, Bernard; Lagrange, Jean-Léon; Correa, Juan C.

2014-01-01

Purpose: To propose a random forest normal tissue complication probability (RF-NTCP) model to predict late rectal toxicity following prostate cancer radiation therapy, and to compare its performance to that of classic NTCP models. Methods and Materials: Clinical data and dose-volume histograms (DVH) were collected from 261 patients who received 3-dimensional conformal radiation therapy for prostate cancer with at least 5 years of follow-up. The series was split 1000 times into training and validation cohorts. A RF was trained to predict the risk of 5-year overall rectal toxicity and bleeding. Parameters of the Lyman-Kutcher-Burman (LKB) model were identified and a logistic regression model was fit. The performance of all the models was assessed by computing the area under the receiving operating characteristic curve (AUC). Results: The 5-year grade ≥2 overall rectal toxicity and grade ≥1 and grade ≥2 rectal bleeding rates were 16%, 25%, and 10%, respectively. Predictive capabilities were obtained using the RF-NTCP model for all 3 toxicity endpoints, including both the training and validation cohorts. The age and use of anticoagulants were found to be predictors of rectal bleeding. The AUC for RF-NTCP ranged from 0.66 to 0.76, depending on the toxicity endpoint. The AUC values for the LKB-NTCP were statistically significantly inferior, ranging from 0.62 to 0.69. Conclusions: The RF-NTCP model may be a useful new tool in predicting late rectal toxicity, including variables other than DVH, and thus appears as a strong competitor to classic NTCP models

In silico assessment of the acute toxicity of chemicals: recent advances and new model for multitasking prediction of toxic effect.

Science.gov (United States)

Kleandrova, Valeria V; Luan, Feng; Speck-Planche, Alejandro; Cordeiro, M Natália D S

2015-01-01

The assessment of acute toxicity is one of the most important stages to ensure the safety of chemicals with potential applications in pharmaceutical sciences, biomedical research, or any other industrial branch. A huge and indiscriminate number of toxicity assays have been carried out on laboratory animals. In this sense, computational approaches involving models based on quantitative-structure activity/toxicity relationships (QSAR/QSTR) can help to rationalize time and financial costs. Here, we discuss the most significant advances in the last 6 years focused on the use of QSAR/QSTR models to predict acute toxicity of drugs/chemicals in laboratory animals, employing large and heterogeneous datasets. The advantages and drawbacks of the different QSAR/QSTR models are analyzed. As a contribution to the field, we introduce the first multitasking (mtk) QSTR model for simultaneous prediction of acute toxicity of compounds by considering different routes of administration, diverse breeds of laboratory animals, and the reliability of the experimental conditions. The mtk-QSTR model was based on artificial neural networks (ANN), allowing the classification of compounds as toxic or non-toxic. This model correctly classified more than 94% of the 1646 cases present in the whole dataset, and its applicability was demonstrated by performing predictions of different chemicals such as drugs, dietary supplements, and molecules which could serve as nanocarriers for drug delivery. The predictions given by the mtk-QSTR model are in very good agreement with the experimental results.

Prediction of human population responses to toxic compounds by a collaborative competition.

Science.gov (United States)

Eduati, Federica; Mangravite, Lara M; Wang, Tao; Tang, Hao; Bare, J Christopher; Huang, Ruili; Norman, Thea; Kellen, Mike; Menden, Michael P; Yang, Jichen; Zhan, Xiaowei; Zhong, Rui; Xiao, Guanghua; Xia, Menghang; Abdo, Nour; Kosyk, Oksana; Friend, Stephen; Dearry, Allen; Simeonov, Anton; Tice, Raymond R; Rusyn, Ivan; Wright, Fred A; Stolovitzky, Gustavo; Xie, Yang; Saez-Rodriguez, Julio

2015-09-01

The ability to computationally predict the effects of toxic compounds on humans could help address the deficiencies of current chemical safety testing. Here, we report the results from a community-based DREAM challenge to predict toxicities of environmental compounds with potential adverse health effects for human populations. We measured the cytotoxicity of 156 compounds in 884 lymphoblastoid cell lines for which genotype and transcriptional data are available as part of the Tox21 1000 Genomes Project. The challenge participants developed algorithms to predict interindividual variability of toxic response from genomic profiles and population-level cytotoxicity data from structural attributes of the compounds. 179 submitted predictions were evaluated against an experimental data set to which participants were blinded. Individual cytotoxicity predictions were better than random, with modest correlations (Pearson's r < 0.28), consistent with complex trait genomic prediction. In contrast, predictions of population-level response to different compounds were higher (r < 0.66). The results highlight the possibility of predicting health risks associated with unknown compounds, although risk estimation accuracy remains suboptimal.

Prediction of acute inhalation toxicity using in vitro lung surfactant inhibition

DEFF Research Database (Denmark)

Sørli, Jorid Birkelund; Huang, Yishi; Da Silva, Emilie

2018-01-01

impregnation products using the constant flow through set-up of the constrained drop surfactometer to determine if they inhibited LS function or not. The same products were tested in a mouse inhalation bioassay to determine their toxicity in vivo. The sensitivity was 100%, i.e. the in vitro method predicted...... the chemical composition of the products and induction of toxicity. The currently accepted method for determination of acute inhalation toxicity is based on experiments on animals; it is time-consuming, expensive and causes stress for the animals. Impregnation products are present on the market in large...... numbers and amounts and exhibit great variety. Therefore, an alternative method to screen for acute inhalation toxicity is needed. The aim of our study was to determine if inhibition of lung surfactant by impregnation products in vitro could accurately predict toxicity in vivo in mice. We tested 21...

Toxicity assessment of water at different stages of treatment using Microtox assay

Directory of Open Access Journals (Sweden)

Pogorzelec Marta

2017-01-01

Full Text Available Number of potentially toxic hydrophobic organic contaminants e.g. polycyclic aromatic hydrocarbons, pesticides, polychlorinated biphenyls and dioxins having entered aquatic environment, including potential sources of drinking water. Unfortunately, not all micropollutants can be removed during water treatment processes. What is more, disinfectants can react with some organic compounds already present in the water, and form disinfection by-products which also can be toxic. The aim of this study was to assess toxicity of water at different stages of water treatment and to verify usefulness semipermeable membrane devices in monitoring of drinking water. For this purpose, semipermeable membrane devices (SPMDs were deployed in a surface water treatment plant. To determine the effect of water treatment on the presence of toxic micropollutants, study was conducted for a period of 5 months. Three sampling places were chosen: raw water input, stream of water just before disinfection and treated water output. After sampling dialysis in organic solvent was carried out and extracts were then analyzed with the Microtox acute toxicity test. The study has indicated the utility as well as some limitations of combining SPMDs with bioluminescence assay in the monitoring of biological effects of bioavailable hydrophobic pollutants in drinking water.

Toxicity identification evaluations of produced-water effluents

International Nuclear Information System (INIS)

Sauer, T.C.; Costa, H.J.; Brown, J.S.; Ward, T.J.

1997-01-01

Toxicity identification evaluations (TIEs) were performed on 14 produced-water (PW) samples of various salinities from inland and offshore oil- and gas-production facilities operated by different companies in Wyoming, Texas, California, and Louisiana (USA) to evaluate the efficacy of TIE procedures in determining potential toxicants in PW effluents. The research involved acute (24- and 48-h) freshwater and marine toxicity tests on whole PW and PW fractions generated by standard US Environmental Protection Agency and PW-specific fractionation schemes. Factors influencing PW TIEs were investigated, such as the effect of salinity in selecting fractionation manipulations, the effect of toxicity test replication (i.e., reproducibility) in distinguishing changes in toxicities between whole PW and its fractions, and the suitability of different test species in PW TIEs. The results obtained and lessons learned from conducting these PW TIEs are presented in this article. Components, or fractions, contributing to toxicity differed for each PW with no specific fraction being consistently toxic. For most PW samples, toxicity attributed to any one fraction represented only part of the toxicity of the whole sample. However, no more than two fraction types were identified as potential toxicants in any sample. Potential toxicants identified during this study, besides salinity, included acidic and basic organic compound class fractions, particulates removed by filtration at pH 11, ammonia, hydrocarbons, hydrogen sulfide, material removed by pH change, and volatile compounds

Prediction of acute inhalation toxicity using in vitro lung surfactant inhibition.

Science.gov (United States)

Sørli, Jorid B; Huang, Yishi; Da Silva, Emilie; Hansen, Jitka S; Zuo, Yi Y; Frederiksen, Marie; Nørgaard, Asger W; Ebbehøj, Niels E; Larsen, Søren T; Hougaard, Karin S

2018-01-01

Private consumers and professionals may experience acute inhalation toxicity after inhaling aerosolized impregnation products. The distinction between toxic and non-toxic products is difficult to make for producers and product users alike, as there is no clearly described relationship between the chemical composition of the products and induction of toxicity. The currently accepted method for determination of acute inhalation toxicity is based on experiments on animals; it is time-consuming, expensive and causes stress for the animals. Impregnation products are present on the market in large numbers and amounts and exhibit great variety. Therefore, an alternative method to screen for acute inhalation toxicity is needed. The aim of our study was to determine if inhibition of lung surfactant by impregnation products in vitro could accurately predict toxicity in vivo in mice. We tested 21 impregnation products using the constant flow through set-up of the constrained drop surfactometer to determine if the products inhibited surfactant function or not. The same products were tested in a mouse inhalation bioassay to determine their toxicity in vivo. The sensitivity was 100%, i.e., the in vitro method predicted all the products that were toxic for mice to inhale. The specificity of the in vitro test was 63%, i.e., the in vitro method found three false positives in the 21 tested products. Six of the products had been involved in accidental human inhalation where they caused acute inhalation toxicity. All of these six products inhibited lung surfactant function in vitro and were toxic to mice.

Predicting human developmental toxicity of pharmaceuticals using human embryonic stem cells and metabolomics

International Nuclear Information System (INIS)

West, Paul R.; Weir, April M.; Smith, Alan M.; Donley, Elizabeth L.R.; Cezar, Gabriela G.

2010-01-01

Teratogens, substances that may cause fetal abnormalities during development, are responsible for a significant number of birth defects. Animal models used to predict teratogenicity often do not faithfully correlate to human response. Here, we seek to develop a more predictive developmental toxicity model based on an in vitro method that utilizes both human embryonic stem (hES) cells and metabolomics to discover biomarkers of developmental toxicity. We developed a method where hES cells were dosed with several drugs of known teratogenicity then LC-MS analysis was performed to measure changes in abundance levels of small molecules in response to drug dosing. Statistical analysis was employed to select for specific mass features that can provide a prediction of the developmental toxicity of a substance. These molecules can serve as biomarkers of developmental toxicity, leading to better prediction of teratogenicity. In particular, our work shows a correlation between teratogenicity and changes of greater than 10% in the ratio of arginine to asymmetric dimethylarginine levels. In addition, this study resulted in the establishment of a predictive model based on the most informative mass features. This model was subsequently tested for its predictive accuracy in two blinded studies using eight drugs of known teratogenicity, where it correctly predicted the teratogenicity for seven of the eight drugs. Thus, our initial data shows that this platform is a robust alternative to animal and other in vitro models for the prediction of the developmental toxicity of chemicals that may also provide invaluable information about the underlying biochemical pathways.

In silico prediction of toxicity of non-congeneric industrial chemicals using ensemble learning based modeling approaches

Energy Technology Data Exchange (ETDEWEB)

Singh, Kunwar P., E-mail: kpsingh_52@yahoo.com; Gupta, Shikha

2014-03-15

Ensemble learning approach based decision treeboost (DTB) and decision tree forest (DTF) models are introduced in order to establish quantitative structure–toxicity relationship (QSTR) for the prediction of toxicity of 1450 diverse chemicals. Eight non-quantum mechanical molecular descriptors were derived. Structural diversity of the chemicals was evaluated using Tanimoto similarity index. Stochastic gradient boosting and bagging algorithms supplemented DTB and DTF models were constructed for classification and function optimization problems using the toxicity end-point in T. pyriformis. Special attention was drawn to prediction ability and robustness of the models, investigated both in external and 10-fold cross validation processes. In complete data, optimal DTB and DTF models rendered accuracies of 98.90%, 98.83% in two-category and 98.14%, 98.14% in four-category toxicity classifications. Both the models further yielded classification accuracies of 100% in external toxicity data of T. pyriformis. The constructed regression models (DTB and DTF) using five descriptors yielded correlation coefficients (R{sup 2}) of 0.945, 0.944 between the measured and predicted toxicities with mean squared errors (MSEs) of 0.059, and 0.064 in complete T. pyriformis data. The T. pyriformis regression models (DTB and DTF) applied to the external toxicity data sets yielded R{sup 2} and MSE values of 0.637, 0.655; 0.534, 0.507 (marine bacteria) and 0.741, 0.691; 0.155, 0.173 (algae). The results suggest for wide applicability of the inter-species models in predicting toxicity of new chemicals for regulatory purposes. These approaches provide useful strategy and robust tools in the screening of ecotoxicological risk or environmental hazard potential of chemicals. - Graphical abstract: Importance of input variables in DTB and DTF classification models for (a) two-category, and (b) four-category toxicity intervals in T. pyriformis data. Generalization and predictive abilities of the

In silico prediction of toxicity of non-congeneric industrial chemicals using ensemble learning based modeling approaches

International Nuclear Information System (INIS)

Singh, Kunwar P.; Gupta, Shikha

2014-01-01

Ensemble learning approach based decision treeboost (DTB) and decision tree forest (DTF) models are introduced in order to establish quantitative structure–toxicity relationship (QSTR) for the prediction of toxicity of 1450 diverse chemicals. Eight non-quantum mechanical molecular descriptors were derived. Structural diversity of the chemicals was evaluated using Tanimoto similarity index. Stochastic gradient boosting and bagging algorithms supplemented DTB and DTF models were constructed for classification and function optimization problems using the toxicity end-point in T. pyriformis. Special attention was drawn to prediction ability and robustness of the models, investigated both in external and 10-fold cross validation processes. In complete data, optimal DTB and DTF models rendered accuracies of 98.90%, 98.83% in two-category and 98.14%, 98.14% in four-category toxicity classifications. Both the models further yielded classification accuracies of 100% in external toxicity data of T. pyriformis. The constructed regression models (DTB and DTF) using five descriptors yielded correlation coefficients (R 2 ) of 0.945, 0.944 between the measured and predicted toxicities with mean squared errors (MSEs) of 0.059, and 0.064 in complete T. pyriformis data. The T. pyriformis regression models (DTB and DTF) applied to the external toxicity data sets yielded R 2 and MSE values of 0.637, 0.655; 0.534, 0.507 (marine bacteria) and 0.741, 0.691; 0.155, 0.173 (algae). The results suggest for wide applicability of the inter-species models in predicting toxicity of new chemicals for regulatory purposes. These approaches provide useful strategy and robust tools in the screening of ecotoxicological risk or environmental hazard potential of chemicals. - Graphical abstract: Importance of input variables in DTB and DTF classification models for (a) two-category, and (b) four-category toxicity intervals in T. pyriformis data. Generalization and predictive abilities of the

Tracking pyrethroid toxicity in surface water samples: Exposure dynamics and toxicity identification tools for laboratory tests with Hyalella azteca (Amphipoda).

Science.gov (United States)

Deanovic, Linda A; Stillway, Marie; Hammock, Bruce G; Fong, Stephanie; Werner, Inge

2018-02-01

Pyrethroid insecticides are commonly used in pest control and are present at toxic concentrations in surface waters of agricultural and urban areas worldwide. Monitoring is challenging as a result of their high hydrophobicity and low toxicity thresholds, which often fall below the analytical methods detection limits (MDLs). Standard daphnid bioassays used in surface water monitoring are not sensitive enough to protect more susceptible invertebrate species such as the amphipod Hyalella azteca and chemical loss during toxicity testing is of concern. In the present study, we quantified toxicity loss during storage and testing, using both natural and synthetic water, and presented a tool to enhance toxic signal strength for improved sensitivity of H. azteca toxicity tests. The average half-life during storage in low-density polyethylene (LDPE) cubitainers (Fisher Scientific) at 4 °C of 5 pyrethroids (permethrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, and esfenvalerate) and one organophosphate (chlorpyrifos; used as reference) was 1.4 d, and piperonyl butoxide (PBO) proved an effective tool to potentiate toxicity. We conclude that toxicity tests on ambient water samples containing these hydrophobic insecticides are likely to underestimate toxicity present in the field, and mimic short pulse rather than continuous exposures. Where these chemicals are of concern, the addition of PBO during testing can yield valuable information on their presence or absence. Environ Toxicol Chem 2018;37:462-472. © 2017 SETAC. © 2017 SETAC.

ProTox: a web server for the in silico prediction of rodent oral toxicity.

Science.gov (United States)

Drwal, Malgorzata N; Banerjee, Priyanka; Dunkel, Mathias; Wettig, Martin R; Preissner, Robert

2014-07-01

Animal trials are currently the major method for determining the possible toxic effects of drug candidates and cosmetics. In silico prediction methods represent an alternative approach and aim to rationalize the preclinical drug development, thus enabling the reduction of the associated time, costs and animal experiments. Here, we present ProTox, a web server for the prediction of rodent oral toxicity. The prediction method is based on the analysis of the similarity of compounds with known median lethal doses (LD50) and incorporates the identification of toxic fragments, therefore representing a novel approach in toxicity prediction. In addition, the web server includes an indication of possible toxicity targets which is based on an in-house collection of protein-ligand-based pharmacophore models ('toxicophores') for targets associated with adverse drug reactions. The ProTox web server is open to all users and can be accessed without registration at: http://tox.charite.de/tox. The only requirement for the prediction is the two-dimensional structure of the input compounds. All ProTox methods have been evaluated based on a diverse external validation set and displayed strong performance (sensitivity, specificity and precision of 76, 95 and 75%, respectively) and superiority over other toxicity prediction tools, indicating their possible applicability for other compound classes. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Monitoring of heavy/toxic metals and halides in surface/ground water (abstract)

International Nuclear Information System (INIS)

Viqar-un-Nisa; Ahmed, R.; Husain, M.

1999-01-01

Water is essential for maintaining physical and social life. Human and animal consumption is perhaps the most evident essential use of water. Water quality and quantity have become critical issues, affecting all life. The importance of water in our lives, combined with the threats, make water resources use a global problem. Among the different pollutants toxic metals, metalloids and halides have special significance. Industrial effluents and municipal wastewater are normally drained into water streams, rivers and other reservoirs thus polluting these significantly. Quality of our water resources especially is an issue, which continues to arouse the attention of concerned scientists, legislators and the general public. Among various pollutant chemicals, the heavy metals and metalloids are present at trace levels in various compartments of the environment. Some metals become toxic even at trace levels because of the important features that distinguishes metals from other pollutants is that they are not biodegradable. The halides like Cl, Br, and I from different sources can enter easily into water systems and then they make their way directly into the human body. The intake of toxic as wells as essential elements through water and other food items like vegetables, milk wheat flour etc. is significant. The abundance or deficiency of these meals as well as halides results in abnormal metabolic functions. Due to excessive demand for trace analysis in water and other materials a variety of techniques and instrumentation has been developed. Determination of heavy metals ions is of the highest interest in environmental analysis. Among the food materials water is most important because of their large consumption by man. Also toxic metals in water may be in dissolved ionic form, which directly go into human metabolism and start their toxic action. Presence of even small amounts of toxic metals in drinking water can produce serious health hazards. (author)

Prediction of toxicity and comparison of alternatives using WebTEST (Web-services Toxicity Estimation Software Tool)(Bled Slovenia)

Science.gov (United States)

A Java-based web service is being developed within the US EPA’s Chemistry Dashboard to provide real time estimates of toxicity values and physical properties. WebTEST can generate toxicity predictions directly from a simple URL which includes the endpoint, QSAR method, and ...

Toxicity prediction of compounds from turmeric (Curcuma longa L).

Science.gov (United States)

Balaji, S; Chempakam, B

2010-10-01

Turmeric belongs to the ginger family Zingiberaceae. Currently, cheminformatics approaches are not employed in any of the spices to study the medicinal properties traditionally attributed to them. The aim of this study is to find the most efficacious molecule which does not have any toxic effects. In the present study, toxicity of 200 chemical compounds from turmeric were predicted (includes bacterial mutagenicity, rodent carcinogenicity and human hepatotoxicity). The study shows out of 200 compounds, 184 compounds were predicted as toxigenic, 136 compounds are mutagenic, 153 compounds are carcinogenic and 64 compounds are hepatotoxic. To cross validate our results, we have chosen the popular curcumin and found that curcumin and its derivatives may cause dose dependent hepatotoxicity. The results of these studies indicate that, in contrast to curcumin, few other compounds in turmeric which are non-mutagenic, non-carcinogenic, non-hepatotoxic, and do not have any side-effects. Hence, the cost-effective approach presented in this paper could be used to filter toxic compounds from the drug discovery lifecycle. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Toxicity of ionic liquids: Database and prediction via quantitative structure–activity relationship method

International Nuclear Information System (INIS)

Zhao, Yongsheng; Zhao, Jihong; Huang, Ying; Zhou, Qing; Zhang, Xiangping; Zhang, Suojiang

2014-01-01

Highlights: • A comprehensive database on toxicity of ionic liquids (ILs) was established. • Relationship between structure and toxicity of IL has been analyzed qualitatively. • Two new QSAR models were developed for predicting toxicity of ILs to IPC-81. • Accuracy of proposed nonlinear SVM model is much higher than the linear MLR model. • The established models can be explored in designing novel green agents. - Abstract: A comprehensive database on toxicity of ionic liquids (ILs) is established. The database includes over 4000 pieces of data. Based on the database, the relationship between IL's structure and its toxicity has been analyzed qualitatively. Furthermore, Quantitative Structure–Activity relationships (QSAR) model is conducted to predict the toxicities (EC 50 values) of various ILs toward the Leukemia rat cell line IPC-81. Four parameters selected by the heuristic method (HM) are used to perform the studies of multiple linear regression (MLR) and support vector machine (SVM). The squared correlation coefficient (R 2 ) and the root mean square error (RMSE) of training sets by two QSAR models are 0.918 and 0.959, 0.258 and 0.179, respectively. The prediction R 2 and RMSE of QSAR test sets by MLR model are 0.892 and 0.329, by SVM model are 0.958 and 0.234, respectively. The nonlinear model developed by SVM algorithm is much outperformed MLR, which indicates that SVM model is more reliable in the prediction of toxicity of ILs. This study shows that increasing the relative number of O atoms of molecules leads to decrease in the toxicity of ILs

Predicting algal growth inhibition toxicity: three-step strategy using structural and physicochemical properties.

Science.gov (United States)

Furuhama, A; Hasunuma, K; Hayashi, T I; Tatarazako, N

2016-05-01

We propose a three-step strategy that uses structural and physicochemical properties of chemicals to predict their 72 h algal growth inhibition toxicities against Pseudokirchneriella subcapitata. In Step 1, using a log D-based criterion and structural alerts, we produced an interspecies QSAR between algal and acute daphnid toxicities for initial screening of chemicals. In Step 2, we categorized chemicals according to the Verhaar scheme for aquatic toxicity, and we developed QSARs for toxicities of Class 1 (non-polar narcotic) and Class 2 (polar narcotic) chemicals by means of simple regression with a hydrophobicity descriptor and multiple regression with a hydrophobicity descriptor and a quantum chemical descriptor. Using the algal toxicities of the Class 1 chemicals, we proposed a baseline QSAR for calculating their excess toxicities. In Step 3, we used structural profiles to predict toxicity either quantitatively or qualitatively and to assign chemicals to the following categories: Pesticide, Reactive, Toxic, Toxic low and Uncategorized. Although this three-step strategy cannot be used to estimate the algal toxicities of all chemicals, it is useful for chemicals within its domain. The strategy is also applicable as a component of Integrated Approaches to Testing and Assessment.

Potential carcinogenicity predicted by computational toxicity evaluation of thiophosphate pesticides using QSTR/QSCarciAR model.

Science.gov (United States)

Petrescu, Alina-Maria; Ilia, Gheorghe

2017-07-01

This study presents in silico prediction of toxic activities and carcinogenicity, represented by the potential carcinogenicity DSSTox/DBS, based on vector regression with a new Kernel activity, and correlating the predicted toxicity values through a QSAR model, namely: QSTR/QSCarciAR (quantitative structure toxicity relationship/quantitative structure carcinogenicity-activity relationship) described by 2D, 3D descriptors and biological descriptors. The results showed a connection between carcinogenicity (compared to the structure of a compound) and toxicity, as a basis for future studies on this subject, but each prediction is based on structurally similar compounds and the reactivation of the substructures of these compounds.

Avoiding toxicity from water-borne contaminants in hemodialysis: new challenges in an era of increased demand for water.

Science.gov (United States)

Ward, Richard A

2011-05-01

Water is necessary for all hemodialysis treatments. However, drinking water contains a range of substances that are toxic to patients on hemodialysis. Thus, all dialysis facilities are equipped with a water treatment system that removes those substances from the water before it is used to prepare dialysate. Increased demand for water and ever-evolving drinking water regulations are leading to changes in drinking water quality that may compromise the ability of typical dialysis water treatment systems to adequately remove substances that are known to be toxic or to deal with unexpected increases in other substances of unknown toxicity. In addition to these external challenges to dialysis water quality, the growing recognition that microbial contaminants in dialysate contribute to long-term morbidity has led to more stringent microbiological quality standards for dialysate and a consequent need to control biofilm formation in the fluid pathways involved in dialysate preparation. Avoiding toxicity from water contaminants in this dynamic environment requires a comprehensive approach to water treatment, including flexibility regarding the choice of water treatment processes, close communication with the suppliers of drinking water, and an emphasis on training technicians responsible for monitoring and maintaining all aspects of the fluid handling systems. Copyright © 2011 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Use of hydra for chronic toxicity assessment of waters intended for human consumption

International Nuclear Information System (INIS)

Arkhipchuk, Victor V.; Blaise, Christian; Malinovskaya, Maria V.

2006-01-01

Methods developed with the cnidarian, Hydra attenuata (Pallas), have proven effective for screening acute toxicity in aqueous samples, whereas their use in revealing (sub)chronic toxic effects have had mitigated success. We therefore sought to explore manifestations of hydra mortality and abnormal morphological changes, as well as the reproductive capacity of hydras to further enhance the bioassay sensitivity and to assess (sub)chronic toxicity. These parameters were recorded following the onset of experiments after 8, 12 and 19-21 days of hydra exposure. Results obtained with potable waters (30 brands of bottled waters and artesian waters from 9 wells) showed chronic sublethal and lethal effects or reproduction rate inhibition for most samples. The effectiveness of the hydra toxicity test was demonstrated in comparison with other widely used bioassays. Our previous and present investigations suggest that hydra is a reliable and relevant test organism for the assessment of acute and chronic water toxicity. - Hydra is a reliable and relevant test organism for the assessment of acute and chronic toxicity of waters intended for human consumption

Global concentration additivity and prediction of mixture toxicities, taking nitrobenzene derivatives as an example.

Science.gov (United States)

Li, Tong; Liu, Shu-Shen; Qu, Rui; Liu, Hai-Ling

2017-10-01

The toxicity of a mixture depends not only on the mixture concentration level but also on the mixture ratio. For a multiple-component mixture (MCM) system with a definite chemical composition, the mixture toxicity can be predicted only if the global concentration additivity (GCA) is validated. The so-called GCA means that the toxicity of any mixture in the MCM system is the concentration additive, regardless of what its mixture ratio and concentration level. However, many mixture toxicity reports have usually employed one mixture ratio (such as the EC 50 ratio), the equivalent effect concentration ratio (EECR) design, to specify several mixtures. EECR mixtures cannot simulate the concentration diversity and mixture ratio diversity of mixtures in the real environment, and it is impossible to validate the GCA. Therefore, in this paper, the uniform design ray (UD-Ray) was used to select nine mixture ratios (rays) in the mixture system of five nitrobenzene derivatives (NBDs). The representative UD-Ray mixtures can effectively and rationally describe the diversity in the NBD mixture system. The toxicities of the mixtures to Vibrio qinghaiensis sp.-Q67 were determined by the microplate toxicity analysis (MTA). For each UD-Ray mixture, the concentration addition (CA) model was used to validate whether the mixture toxicity is additive. All of the UD-Ray mixtures of five NBDs are global concentration additive. Afterwards, the CA is employed to predict the toxicities of the external mixtures from three EECR mixture rays with the NOEC, EC 30 , and EC 70 ratios. The predictive toxicities are in good agreement with the experimental toxicities, which testifies to the predictability of the mixture toxicity of the NBDs. Copyright © 2017. Published by Elsevier Inc.

FOR SELECTED ORGANIC MICROPOLLUTANTS ELIMINATION AND CHANGE OF WATER TOXICITY

Directory of Open Access Journals (Sweden)

Mariusz Dudziak

2016-12-01

Full Text Available All of the available and applicable chemical oxidants were found to affect the quality of the treated water or wastewater. It has been commonly observed that the oxidation processes generate by-products, which often possess unknown biological activity. Accordingly, the present study assessed the degree of degradation of mixture of selected micropollutants and the change of the solution toxicity in the UV/TiO2/H2O2 hybrid process. Water containing bisphenol A and diclofenac at a concentration of 1 mg/dm3 was treated. For toxicological evaluation of solution sample were used three different tests, ie. enzymatic Microtox® using luminescent strain of marine bacteria Aliivibrio fischeri, survival of the crustaceans Daphnia magna and the growth of duckweed Lemna minor. Decomposition of tested micropollutants depend on the processing time and the type of the oxidizing compound. However, during the process we observed adverse effects of water toxicity. The toxicity was documented in both bacteria and water plant.

Precipitation of metals in produced water : influence on contaminant transport and toxicity

International Nuclear Information System (INIS)

Azetsu-Scott, K.; Wohlgeschaffen, G.; Yeats, P.; Dalziel, J.; Niven, S.; Lee, K.

2006-01-01

Produced water contains a number of compounds of environmental concern and is the largest volume waste stream from oil and gas production activities. Recent studies have shown that chemicals dissolved in waste water from oil platforms stunted the growth of North Sea cod and affected their breeding patterns. Scientific research is needed to identify the impact of produced water discharges on the environment as well as to identify acceptable disposal limits for produced water. This presentation provided details of a study to characterize produced water discharged within the Atlantic regions of Canada. The study included dose response biological effect studies; research on processes controlling the transport and transformation of contaminants associated with produced water discharges and the development of risk assessment models. The sample location for the study was a site near Sable Island off the coast of Nova Scotia. Chemical analysis of the produced water was conducted as well as toxicity tests. Other tests included a time-series particulate matter sedimentation test; time-series metal and toxicity analysis; time-series change in metal precipitates tests and a produced water/seawater layering experiment. Dissolved and particulate fractions were presented, and the relationship between toxicity and particulate concentrations was examined. Results of the study suggested that produced water contaminants are variable over spatial and temporal scales due to source variations and changes in discharge rates. Chemical changes occur within 24 hours of produced water being mixed with seawater and facilitate contaminant partitioning between the surface micro layer, water column and sediments. Changes in the toxicity of the produced water are correlated with the partitioning of chemical components. The impact zone may be influenced by chemical kinetics that control the distribution of potential toxic metals. Further research is needed to investigate the effects of low level

Field Validation of Toxicity Tests to Evaluate the Potential for Beneficial Use of Produced Water

Energy Technology Data Exchange (ETDEWEB)

Joseph Bidwell; Jonathan Fisher; Naomi Cooper

2008-03-31

This study investigated potential biological effects of produced water contamination derived from occasional surface overflow and possible subsurface intrusion at an oil production site along the shore of Skiatook Lake, Oklahoma. We monitored basic chemistry and acute toxicity to a suite of standard aquatic test species (fathead minnow-Pimephales promelas, Daphnia pulex, Daphnia magna, and Ceriodaphnia dubia) in produced water and in samples taken from shallow groundwater wells on the site. Toxicity identification evaluations and ion toxicity modeling were used to identify toxic constituents in the samples. Lake sediment at the oil production site and at a reference site were also analyzed for brine intrusion chemically and by testing sediment toxicity using the benthic invertebrates, Chironomus dilutus, and Hyallela azteca. Sediment quality was also assessed with in situ survival and growth studies with H. azteca and the Asian clam, Corbicula fluminea, and by benthic macroinvertebrate community sampling. The produced water was acutely toxic to the aquatic test organisms at concentrations ranging from 1% to 10% of the whole produced water sample. Toxicity identification evaluation and ion toxicity modeling indicated major ion salts and hydrocarbons were the primary mixture toxicants. The standardized test species used in the laboratory bioassays exhibited differences in sensitivity to these two general classes of contaminants, which underscores the importance of using multiple species when evaluating produced water toxicity. Toxicity of groundwater was greater in samples from wells near a produced water injection well and an evaporation pond. Principle component analyses (PCA) of chemical data derived from the groundwater wells indicated dilution by lake water and possible biogeochemical reactions as factors that ameliorated groundwater toxicity. Elevated concentrations of major ions were found in pore water from lake sediments, but toxicity from these ions was

[The toxicity variation of organic extracts in drinking water treatment processes].

Science.gov (United States)

Mei, M; Wei, S; Zijian, W; Wenhua, W; Baohua, Z; Suxia, Z

2001-01-01

Source water samples and outlet water samples from different treatment processes of the Beijing Ninth Water Works were concentrated in situ with XAD-2 filled columns. GC-MS analysis and toxic assessment including acute toxicity evaluation by luminescent bacterium bioassay(Q67 strains) and mutagenicity assessment by Ames test(TA98 and TA100 strains with and without S9 addition) were conducted on these samples. The results showed that prechlorination caused the direct and indirect frame shift mutagenicity as well as indirect base pair substitute mutagenicity. Addition of coagulant may increase the base pair substitute mutagenic effects greatly. Sand and coal filtration and granular activated carbon filtration could effectively remove most of the formed mutagens. The rechlorination do not obviously increase the mutagenic effects. No mutagenic effect was observed in tap water. Acute toxicity showed the same variation with that of mutagenicity during the treatment processes. Sample from flocculation treatment process was found to be the most toxic sample. Results of GC-MS analysis showed that water in this plant was not contaminated by PCB. Concentrations of toluene, naphthalene and phenol increased in flocculation treatment process and in tap water. However, the concentrations of these substances were at the level of microgram/L, therefore, were not high enough to cause mutagenicity.

LEVEL OF TOXICITY WATER AREA «TULENIY» AS A RESULT OF BIOASSAY

Directory of Open Access Journals (Sweden)

A. F. Sokolsky

2014-01-01

Full Text Available Aim. To determine the toxicity of marine waters area " tuleniy ".Location. Area " tuleniy ".Methods. Determining the level of toxicity of marine waters area "seal" method for biological testing was conducted according tothe guidelines approved by the Ministry of natural resources (guidance on the definition of ..., 2002; Dolzhenko, 1978. Guide prepared by the Center for Russian register of hydraulic structures and the state water cadastre of the MNR of Russia jointly with specialists of the Institute Committee of Russia and the UNION of ecological problems of the Ministry of Ukraine. The basis of the proposed system of marine toxicity biotests based on the results of generalization of experimental research based on the problem of pollution of water bodies and numerous literature data, making it possible to identify features of the response of aquatic organisms of different taxonomic groups to toxic impurities of different nature and origin. Experimental studies were conducted on the culture of marine unicellular algae Phaeodactylum tricornutum on planktonic crustacea Acartia tonsa, the larvae of the chironomid Chironomus gr.salinarius and juvenile guppies Poecillia reticulata Peters.Results. Comparative analysis of the results of research from 2001 to 2006 showed no acute toxic effect on the test object zooplankton and phytoplanton.Main conclusions. Throughout the study period (2001-2003, 2005-2006, you must allocate the spring of 2002, when it was recorded,the average of the lowest five years of research, the level of toxicity of water for the analyzed area.Considering the results of biological testing of the surveyed area by periods, it should be noted that the average level of toxicity of the waters did not undergo significant changes and were on the same level, not exceeding 17,6% (table. 1. According to the classification shown in table 2, the water in the surveyed area is assessed as "non-toxic".

Investigation of the potential influence of production treatment chemicals on produced water toxicity

International Nuclear Information System (INIS)

Stine, E.R.; Gala, W.R.; Henry, L.R.

1993-01-01

Production treatment chemicals represent a diverse collection of chemical classes, added at various points from the wellhead to the final flotation cell, to prevent operational upsets and enhance the separation of oil from water. Information in the literature indicates that while many treatment chemicals are thought to partition into oil and not into the produced water, there are cases where a sufficiently water soluble treatment chemical is added at high enough concentrations to suggest that the treatment chemical may add to the aquatic toxicity of the produced water. A study was conducted to evaluate the potential effect of production treatment chemicals on the toxicity of produced waters using the US EPA Seven-day Mysidopsis bahia Survival, Growth and Fecundity Test. Samples of produced water were collected and tested for toxicity from three platforms under normal operating conditions, followed by repeated sampling and testing after a 72-hour period in which treatment chemical usage was discontinued, to the degree possible. Significant reductions in produced water toxicity were observed for two of the three platforms tested following either cessation of treatment chemical usage, or by comparing the toxicity of samples collected upstream and downstream of the point of treatment chemical addition

Validation of a biotic ligand model on site-specific copper toxicity to Daphnia magna in the Yeongsan River, Korea.

Science.gov (United States)

Park, Jinhee; Ra, Jin-Sung; Rho, Hojung; Cho, Jaeweon; Kim, Sang Don

2018-03-01

The objective of this study was to determine whether the water effect ratio (WER) or biotic ligand model (BLM) could be applied to efficiently develop water quality criteria (WQC) in Korea. Samples were collected from 12 specific sites along the Yeongsan River (YSR), Korea, including two sewage treatment plants and one estuary lake. A copper toxicity test using Daphnia magna was performed to determine the WER and to compare to the BLM prediction. The results of the WER from YSR samples also indicated significantly different copper toxicities in all sites. The model-based predictions showed that effluent and estuary waters had significantly different properties in regard to their ability to be used to investigate water characteristics and copper toxicity. It was supposed that the slight water characteristics changes, such as pH, DOC, hardness, conductivity, among others, influence copper toxicity, and these variable effects on copper toxicity interacted with the water composition. The 38% prediction was outside of the validation range by a factor of two in all sites, showing a poor predictive ability, especially in STPs and streams adjacent to the estuary, while the measured toxicity was more stable. The samples that ranged from pH 7.3-7.7 generated stable predictions, while other samples, including those with lower and the higher pH values, led to more unstable predictions. The results also showed that the toxicity of Cu in sample waters to D. magna was closely proportional to the amounts of acidity, including the carboxylic and phenolic groups, as well as the DOC concentrations. Consequently, the acceptable prediction of metal toxicity in various water samples needs the site-specific results considering the water characteristics such as pH and DOC properties particularly in STPs and estuary regions. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute and chronic toxicity studies of the water extract from dried ...

African Journals Online (AJOL)

Acute and chronic toxicities of the water extract from the dried fruits of Terminalia bellerica (Gaertn.) Roxb. were assessed in both female and male rats. For the study of acute toxicity, a single oral administration of the water extract at a dose of 5,000 mg/kg body weight (10 female, 10 male) was performed and the results ...

Renal Cell Toxicity of Water-Soluble Coal Extracts from the Gulf Coast

Science.gov (United States)

Ojeda, A. S.; Ford, S.; Ihnat, M.; Gallucci, R. M.; Philp, P. R.

2017-12-01

In the Gulf Coast, many rural residents rely on private well water for drinking, cooking, and other domestic needs. A large portion of this region contains lignite coal deposits within shallow aquifers that potentially leach organic matter into the water supply. It is proposed that the organic matter leached from low-rank coal deposits contributes to the development of kidney disease, however, little work has been done to investigate the toxicity of coal extracts. In this study, human kidney cells (HK-2) were exposed to water-soluble extracts of Gulf Coast Coals to assess toxicity. Cell viability was measured by direct counts of total and necrotic cells. A dose-response curve was used to generate IC50 values, and the extracts showed significant toxicity that ranged from 0.5% w/v to 3% w/v IC50. The most toxic extract was from Louisiana where coal-derived organic material has been previously linked to high incidents of renal pelvic cancer (RPC). Although the toxic threshold measured in this study is significantly higher than the concentration of organic matter in the groundwater, typically affected areas may consume contaminated water over a lifetime. It is possible that the cumulative toxic effects of coal-derived material contribute to the development of disease.

Dredged Material Evaluations: Review of Zooplankton Toxicity Test Methods for Marine Water Quality Evaluations

Science.gov (United States)

2016-09-01

term impacts of the DM while settling through the water column (elutriate toxicity tests), and long-term toxicity (whole sediment toxicity tests) and...elutriates are prepared according to guidance (USEPA/USACE 1991; 1998) by mixing sediment and site water and allowing settling for prescribed periods...of water and waste water . 17th ed. Washington, DC: APHA. Arnold, W. R., R. L. Diamond, and D. S. Smith. 2010a. The effects of salinity, pH, and

Spatial and temporal distributions of toxicity in receiving waters around an oil effluent discharge site

International Nuclear Information System (INIS)

Krause, P.R.

1994-01-01

Distributions of pollutants from a point source discharge within the water column may vary in both time and space. In this study, they examined the spatial and temporal patterns of toxicity from an oil production effluent (produced water) discharge plume using sea urchin fertilization and development bioassays. Specifically, they tested the sensitivity and response patterns of sea urchin gametes and early life stages exposed to receiving waters sampled along a 1 km transact near an active produced water outfall. Fertilization success and development of larvae to the pluteus stage varied significantly with proximity to the outfall, with reduced fertilization and larval development found closer to the outfall. Although estimated toxicity in receiving water samples, based on fertilization success, was variable in time -- perhaps responding to variation in the quantity or make-up of produced water discharges -- the general spatial pattern of toxicity along the sampling transact remained relatively constant. Strong evidence that field toxicity was directly attributable to produced water effluents was provided by sampling the receiving waters while the produced water discharge was not operating. At such a time, no toxicity was found at any of the field sites. Receiving water toxicity data, along with toxicity data from the effluent itself, were used to prepare a ''map'' of effective effluent concentrations along the sampling transect

Evaluation of a novel automated water analyzer for continuous monitoring of toxicity and chemical parameters in municipal water supply.

Science.gov (United States)

Bodini, Sergio F; Malizia, Marzio; Tortelli, Annalisa; Sanfilippo, Luca; Zhou, Xingpeng; Arosio, Roberta; Bernasconi, Marzia; Di Lucia, Stefano; Manenti, Angela; Moscetta, Pompeo

2018-08-15

A novel tool, the DAMTA analyzer (Device for Analytical Monitoring and Toxicity Assessment), designed for fully automated toxicity measurements based on luminescent bacteria as well as for concomitant determination of chemical parameters, was developed and field-tested. The instrument is a robotic water analyzer equipped with a luminometer and a spectrophotometer, integrated on a thermostated reaction plate which contains a movable carousel with 80 cuvettes. Acute toxicity is measured on-line using a wild type Photobacterium phosphoreum strain with measurable bioluminescence and unaltered sensitivity to toxicants lasting up to ten days. The EC50 values of reference compounds tested were consistent with A. fischeri and P. phosphoreum international standards and comparable to previously published data. Concurrently, a laboratory trial demonstrated the feasibility of use of the analyzer for the determination of nutrients and metals in parallel to the toxicity measurements. In a prolonged test, the system was installed only in toxicity mode at the premises of the World Fair "Expo Milano-2015″, a high security site to ensure the quality of the supplied drinking water. The monitoring program lasted for six months during which ca. 2400 toxicity tests were carried out; the results indicated a mean non-toxic outcome of -5.5 ± 6.2%. In order to warrant the system's robustness in detecting toxic substances, Zn was measured daily with highly reproducible inhibition results, 70.8 ± 13.6%. These results assure that this novel toxicity monitor can be used as an early warning system for protection of drinking water sources from emergencies involving low probability/high impact contamination events in source water or treated water. Copyright © 2018 Elsevier Inc. All rights reserved.

Toxicity of sediments and pore water from Brunswick Estuary, Georgia

Science.gov (United States)

Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

1993-01-01

A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

Predictive factors for gastroduodenal toxicity based on endoscopy following radiotherapy in patients with hepatocellular carcinoma

Energy Technology Data Exchange (ETDEWEB)

Yoon, H. [Sungkyunkwan Univ., Seoul (Korea, Republic of). Dept. of Health Sciences and Technology; Oh, D.; Park, H.C.; Han, Y.; Lim, D.H. [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of). Dept. of Radiation Oncology; Kang, S.W. [Korea Univ., Seoul (Korea, Republic of). Dept. of Radiologic Science; Paik, S.W. [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of). Dept. of Medicine

2013-07-15

Purpose: The aim of this work was to determine predictive factors for gastroduodenal (GD) toxicity in hepatocellular carcinoma (HCC) patients who were treated with radiotherapy (RT). Patients and methods: A total of 90 HCC patients who underwent esophagogastroduodenoscopy (EGD) before and after RT were enrolled. RT was delivered as 30-50 Gy (median 37.5 Gy) in 2-5 Gy (median 3.5 Gy) per fraction. All endoscopic findings were reviewed and GD toxicities related to RT were graded by the Common Toxicity Criteria for Adverse Events, version 3.0. The predictive factors for the {>=} grade 2 GD toxicity were investigated. Results: Endoscopic findings showed erosive gastritis in 14 patients (16 %), gastric ulcers in 8 patients (9 %), erosive duodenitis in 15 patients (17 %), and duodenal ulcers in 14 patients (16 %). Grade 2 toxicity developed in 19 patients (21 %) and grade 3 toxicity developed in 8 patients (9 %). V{sub 25} for stomach and V{sub 35} for duodenum (volume receiving a RT dose of more than x Gy) were the most predictive factors for {>=} grade 2 toxicity. The gastric toxicity rate at 6 months was 2.9 % for V{sub 25} {<=} 6.3 % and 57.1 % for V{sub 25} > 6.3 %. The duodenal toxicity rate at 6 months was 9.4 % for V{sub 35} > 5.4 % and 45.9 % for V{sub 35} > 5.4 %. By multivariate analysis including the clinical factors, V{sub 25} for stomach and V{sub 35} for duodenum were the significant factors. Conclusion: EGD revealed that GD toxicity is common following RT for HCC. V{sub 25} for the stomach and V{sub 35} for the duodenum were the significant factors to predict {>=} grade 2 GD toxicity. (orig.)

Presence, origin and importance of toxic substances in drinking water

Energy Technology Data Exchange (ETDEWEB)

Seemayer, N H

1980-01-01

The ubiquitous, environmental toxic substances representing a risk to health, and of importance with respect to the production of drinking water, largely belong to the following groups: cancerogenic, polycyclic, aromatic hydrocarbons, aromatic amines, N-nitroso compounds, pesticides. In addition the following substances: polychlorinated biphenyls, hormones, antibiotics, halogen hydrocarbons and heavy metals such as mercury, cadmium, lead, vanadium, chromium etc. Today, there is full appreciation of the qualitative aspects associated with the burdening of the environmental factor 'water' with toxic substances. However, as to the quantitative aspects, especially those relating to a combined effect of toxic substances adding to the total burden of man with noxious environmental agents, data are still lacking. The assessment of the chronic action exercised by minute and very minute concentrations of potentially toxic, cancerogenic or mutagenic substances possess a particularly complex problem for the environmental and water hygiene. Nowadays, there are basically 3 possibilities of solving this problem: epidemiological-statistical analyses, long-term animal experiments and in-vitro short-term tests. The epidemiological-statistical analysis can make a valuable contribution to the evaluation of the risk to human health of polluted drinking water and may also furnish the first clues to an incipient danger. However, it has to be considered that epidemiological studies deal with multifactorial events and that a monocausality is difficult to establish.

Predicting acute aquatic toxicity of structurally diverse chemicals in fish using artificial intelligence approaches.

Science.gov (United States)

Singh, Kunwar P; Gupta, Shikha; Rai, Premanjali

2013-09-01

The research aims to develop global modeling tools capable of categorizing structurally diverse chemicals in various toxicity classes according to the EEC and European Community directives, and to predict their acute toxicity in fathead minnow using set of selected molecular descriptors. Accordingly, artificial intelligence approach based classification and regression models, such as probabilistic neural networks (PNN), generalized regression neural networks (GRNN), multilayer perceptron neural network (MLPN), radial basis function neural network (RBFN), support vector machines (SVM), gene expression programming (GEP), and decision tree (DT) were constructed using the experimental toxicity data. Diversity and non-linearity in the chemicals' data were tested using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. Predictive and generalization abilities of various models constructed here were compared using several statistical parameters. PNN and GRNN models performed relatively better than MLPN, RBFN, SVM, GEP, and DT. Both in two and four category classifications, PNN yielded a considerably high accuracy of classification in training (95.85 percent and 90.07 percent) and validation data (91.30 percent and 86.96 percent), respectively. GRNN rendered a high correlation between the measured and model predicted -log LC50 values both for the training (0.929) and validation (0.910) data and low prediction errors (RMSE) of 0.52 and 0.49 for two sets. Efficiency of the selected PNN and GRNN models in predicting acute toxicity of new chemicals was adequately validated using external datasets of different fish species (fathead minnow, bluegill, trout, and guppy). The PNN and GRNN models showed good predictive and generalization abilities and can be used as tools for predicting toxicities of structurally diverse chemical compounds. Copyright © 2013 Elsevier Inc. All rights reserved.

Sirc-cvs cytotoxicity test: an alternative for predicting rodent acute systemic toxicity.

Science.gov (United States)

Kitagaki, Masato; Wakuri, Shinobu; Hirota, Morihiko; Tanaka, Noriho; Itagaki, Hiroshi

2006-10-01

An in vitro crystal violet staining method using the rabbit cornea-derived cell line (SIRC-CVS) has been developed as an alternative to predict acute systemic toxicity in rodents. Seventy-nine chemicals, the in vitro cytotoxicity of which was already reported by the Multicenter Evaluation of In vitro Toxicity (MEIC) and ICCVAM/ECVAM, were selected as test compounds. The cells were incubated with the chemicals for 72 hrs and the IC(50) and IC(35) values (microg/mL) were obtained. The results were compared to the in vivo (rat or mouse) "most toxic" oral, intraperitoneal, subcutaneous and intravenous LD(50) values (mg/kg) taken from the RTECS database for each of the chemicals by using Pearson's correlation statistics. The following parameters were calculated: accuracy, sensitivity, specificity, prevalence, positive predictability, and negative predictability. Good linear correlations (Pearson's coefficient; r>0.6) were observed between either the IC(50) or the IC(35) values and all the LD(50) values. Among them, a statistically significant high correlation (r=0.8102, p50) values and the oral LD(50) values. By using the cut-off concentrations of 2,000 mg/kg (LD(50)) and 4,225 microg/mL (IC(50)), no false negatives were observed, and the accuracy was 84.8%. From this, it is concluded that this method could be used to predict the acute systemic toxicity potential of chemicals in rodents.

Use of computer-assisted prediction of toxic effects of chemical substances

International Nuclear Information System (INIS)

Simon-Hettich, Brigitte; Rothfuss, Andreas; Steger-Hartmann, Thomas

2006-01-01

The current revision of the European policy for the evaluation of chemicals (REACH) has lead to a controversy with regard to the need of additional animal safety testing. To avoid increases in animal testing but also to save time and resources, alternative in silico or in vitro tests for the assessment of toxic effects of chemicals are advocated. The draft of the original document issued in 29th October 2003 by the European Commission foresees the use of alternative methods but does not give further specification on which methods should be used. Computer-assisted prediction models, so-called predictive tools, besides in vitro models, will likely play an essential role in the proposed repertoire of 'alternative methods'. The current discussion has urged the Advisory Committee of the German Toxicology Society to present its position on the use of predictive tools in toxicology. Acceptable prediction models already exist for those toxicological endpoints which are based on well-understood mechanism, such as mutagenicity and skin sensitization, whereas mechanistically more complex endpoints such as acute, chronic or organ toxicities currently cannot be satisfactorily predicted. A potential strategy to assess such complex toxicities will lie in their dissection into models for the different steps or pathways leading to the final endpoint. Integration of these models should result in a higher predictivity. Despite these limitations, computer-assisted prediction tools already today play a complementary role for the assessment of chemicals for which no data is available or for which toxicological testing is impractical due to the lack of availability of sufficient compounds for testing. Furthermore, predictive tools offer support in the screening and the subsequent prioritization of compound for further toxicological testing, as expected within the scope of the European REACH program. This program will also lead to the collection of high-quality data which will broaden the

Identifying developmental vascular disruptor compounds using a predictive signature and alternative toxicity models

Science.gov (United States)

Identifying Developmental Vascular Disruptor Compounds Using a Predictive Signature and Alternative Toxicity Models Presenting Author: Tamara Tal Affiliation: U.S. EPA/ORD/ISTD, RTP, NC, USA Chemically induced vascular toxicity during embryonic development can result in a wide...

The Effects of Temperature and Hydrostatic Pressure on Metal Toxicity: Insights into Toxicity in the Deep Sea.

Science.gov (United States)

Brown, Alastair; Thatje, Sven; Hauton, Chris

2017-09-05

Mineral prospecting in the deep sea is increasing, promoting concern regarding potential ecotoxicological impacts on deep-sea fauna. Technological difficulties in assessing toxicity in deep-sea species has promoted interest in developing shallow-water ecotoxicological proxy species. However, it is unclear how the low temperature and high hydrostatic pressure prevalent in the deep sea affect toxicity, and whether adaptation to deep-sea environmental conditions moderates any effects of these factors. To address these uncertainties we assessed the effects of temperature and hydrostatic pressure on lethal and sublethal (respiration rate, antioxidant enzyme activity) toxicity in acute (96 h) copper and cadmium exposures, using the shallow-water ecophysiological model organism Palaemon varians. Low temperature reduced toxicity in both metals, but reduced cadmium toxicity significantly more. In contrast, elevated hydrostatic pressure increased copper toxicity, but did not affect cadmium toxicity. The synergistic interaction between copper and cadmium was not affected by low temperature, but high hydrostatic pressure significantly enhanced the synergism. Differential environmental effects on toxicity suggest different mechanisms of action for copper and cadmium, and highlight that mechanistic understanding of toxicity is fundamental to predicting environmental effects on toxicity. Although results infer that sensitivity to toxicants differs across biogeographic ranges, shallow-water species may be suitable ecotoxicological proxies for deep-sea species, dependent on adaptation to habitats with similar environmental variability.

Effect of water hardness on peracetic acid toxicity to zebrafish, Danio rerio, embryos

DEFF Research Database (Denmark)

Marchand, Pierre_André; Strauss, David L.; Wienke, Andreas

2013-01-01

The use of peracetic acid (PAA) in aquaculture has been suggested as an alternative therapeutic agent. Few data are available concerning fish toxicity by PAA or factors that modify this toxicity. The aim of this study was to investigate the influence of water hardness on the acute toxicity of PAA...... acidic in low hardness. In conclusion, aquaculturists using PAA should pay attention to water hardness to avoid acidosis...

Lead toxicity to Lemna minor predicted using a metal speciation chemistry approach.

Science.gov (United States)

Antunes, Paula M C; Kreager, Nancy J

2014-10-01

In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5-12.5 mg/L dissolved organic carbon, pH of 5.4-8.3, and water hardness of 8-266 mg/L CaCO3 ). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH} ) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r(2)  = 0.998, p minor and highlight the importance of chemical speciation in Pb-based risk assessments for aquatic macrophytes. © 2014 SETAC.

Toxic pressure of herbicides on microalgae in Dutch estuarine and coastal waters

Science.gov (United States)

Booij, Petra; Sjollema, Sascha B.; van der Geest, Harm G.; Leonards, Pim E. G.; Lamoree, Marja H.; de Voogt, W. Pim; Admiraal, Wim; Laane, Remi W. P. M.; Vethaak, A. Dick

2015-08-01

For several decades now, there has been an increase in the sources and types of chemicals in estuarine and coastal waters as a consequence of anthropogenic activities. This has led to considerable concern about the effects of these chemicals on the marine food chain. The fact is that estuarine and coastal waters are the most productive ecosystems with high primary production by microalgae. The toxic pressure of specific phytotoxic chemicals now poses a major threat to these ecosystems. In a previous study, six herbicides (atrazine, diuron, irgarol, isoproturon, terbutryn and terbutylazine) were identified as the main contaminants affecting photosynthesis in marine microalgae. The purpose of this study is to investigate the toxic pressure of these herbicides in the Dutch estuarine and coastal waters in relation to the effective photosystem II efficiency (ΦPSII) in microalgae. Temporal and spatial variations in the concentrations of these herbicides were analyzed based on monitoring data. Additionally, a field study was carried out in which chemical analysis of water was performed and also a toxicity assessment using the Pulse Amplitude Modulation (PAM) fluorometry assay that measures ΦPSII. The toxic pressure on ΦPSII in microalgae has decreased with 55-82% from 2003 to 2012, with the Western Scheldt estuary showing the highest toxic pressure. By combining toxicity data from the PAM assay with chemical analysis of herbicide concentrations, we have identified diuron and terbutylazine as the main contributors to the toxic pressure on microalgae. Although direct effects are not expected, the toxic pressure is close to the 10% effect level in the PAM assay. A compliance check with the current environmental legislation of the European Union revealed that the quality standards are not sufficient to protect marine microalgae.

Predicting the aquatic toxicity mode of action using logistic regression and linear discriminant analysis.

Science.gov (United States)

Ren, Y Y; Zhou, L C; Yang, L; Liu, P Y; Zhao, B W; Liu, H X

2016-09-01

The paper highlights the use of the logistic regression (LR) method in the construction of acceptable statistically significant, robust and predictive models for the classification of chemicals according to their aquatic toxic modes of action. Essentials accounting for a reliable model were all considered carefully. The model predictors were selected by stepwise forward discriminant analysis (LDA) from a combined pool of experimental data and chemical structure-based descriptors calculated by the CODESSA and DRAGON software packages. Model predictive ability was validated both internally and externally. The applicability domain was checked by the leverage approach to verify prediction reliability. The obtained models are simple and easy to interpret. In general, LR performs much better than LDA and seems to be more attractive for the prediction of the more toxic compounds, i.e. compounds that exhibit excess toxicity versus non-polar narcotic compounds and more reactive compounds versus less reactive compounds. In addition, model fit and regression diagnostics was done through the influence plot which reflects the hat-values, studentized residuals, and Cook's distance statistics of each sample. Overdispersion was also checked for the LR model. The relationships between the descriptors and the aquatic toxic behaviour of compounds are also discussed.

THE FUTURE OF TOXICOLOGY-PREDICTIVE TOXICOLOGY: AN EXPANDED VIEW OF CHEMICAL TOXICITY

Science.gov (United States)

A chemistry approach to predictive toxicology relies on structure−activity relationship (SAR) modeling to predict biological activity from chemical structure. Such approaches have proven capabilities when applied to well-defined toxicity end points or regions of chemical space. T...

Bioelectrochemical biosensor for water toxicity detection: generation of dual signals for electrochemical assay confirmation.

Science.gov (United States)

Yang, Yuan; Wang, Yan-Zhai; Fang, Zhen; Yu, Yang-Yang; Yong, Yang-Chun

2018-02-01

Toxicity assessment of water is of great important to the safety of human health and to social security because of more and more toxic compounds that are spilled into the aquatic environment. Therefore, the development of fast and reliable toxicity assessment methods is of great interest and attracts much attention. In this study, by using the electrochemical activity of Shewanella oneidensis MR-1 cells as the toxicity indicator, 3,5-dichlorophenol (DCP) as the model toxic compound, a new biosensor for water toxicity assessment was developed. Strikingly, the presence of DCP in the water significantly inhibited the maximum current output of the S. oneidensis MR-1 in a three-electrode system and also retarded the current evolution by the cells. Under the optimized conditions, the maximum current output of the biosensor was proportional to the concentration of DCP up to 30 mg/L. The half maximal inhibitory concentration of DCP determined by this biosensor is about 14.5 mg/L. Furthermore, simultaneous monitoring of the retarded time (Δt) for current generation allowed the identification of another biosensor signal in response to DCP which could be employed to verify the electrochemical result by dual confirmation. Thus, the present study has provided a reliable and promising approach for water quality assessment and risk warning of water toxicity.

Study on mutagenic and toxic compounds in lake water used as drinking water supply

International Nuclear Information System (INIS)

Monarca, S.; Zanardini, A.

1996-01-01

Trace amounts of mutagenic and toxic substances are frequently found in drinking water, causing a great concern for their potential health effects. Aim of this work is to develop a reliable and efficient screening method for detecting aquatic mutagens and toxins in surface water used for human consumption. For this purpose different methods of concentration of lake water have been experimented by using three different solid phase extraction systems at different pHs and studying the adsorbates by means of a mutagenicity test (Ames test), a toxicity test (LUMIStox) and chemical analysis (GC,MS). This integrated chemical/biological approach showed to be a suitable system for the preliminary choice of an efficient screening method for aquatic mutagens and toxins and to give useful data for the evaluation of potential health hazards

GHS additivity formula: can it predict the acute systemic toxicity of agrochemical formulations that contain acutely toxic ingredients?

Science.gov (United States)

Van Cott, Andrew; Hastings, Charles E; Landsiedel, Robert; Kolle, Susanne; Stinchcombe, Stefan

2018-02-01

In vivo acute systemic testing is a regulatory requirement for agrochemical formulations. GHS specifies an alternative computational approach (GHS additivity formula) for calculating the acute toxicity of mixtures. We collected acute systemic toxicity data from formulations that contained one of several acutely-toxic active ingredients. The resulting acute data set includes 210 formulations tested for oral toxicity, 128 formulations tested for inhalation toxicity and 31 formulations tested for dermal toxicity. The GHS additivity formula was applied to each of these formulations and compared with the experimental in vivo result. In the acute oral assay, the GHS additivity formula misclassified 110 formulations using the GHS classification criteria (48% accuracy) and 119 formulations using the USEPA classification criteria (43% accuracy). With acute inhalation, the GHS additivity formula misclassified 50 formulations using the GHS classification criteria (61% accuracy) and 34 formulations using the USEPA classification criteria (73% accuracy). For acute dermal toxicity, the GHS additivity formula misclassified 16 formulations using the GHS classification criteria (48% accuracy) and 20 formulations using the USEPA classification criteria (36% accuracy). This data indicates the acute systemic toxicity of many formulations is not the sum of the ingredients' toxicity (additivity); but rather, ingredients in a formulation can interact to result in lower or higher toxicity than predicted by the GHS additivity formula. Copyright © 2018 Elsevier Inc. All rights reserved.

Small Microbial Three-Electrode Cell Based Biosensor for Online Detection of Acute Water Toxicity.

Science.gov (United States)

Yu, Dengbin; Zhai, Junfeng; Liu, Changyu; Zhang, Xueping; Bai, Lu; Wang, Yizhe; Dong, Shaojun

2017-11-22

The monitoring of toxicity of water is very important to estimate the safety of drinking water and the level of water pollution. Herein, a small microbial three-electrode cell (M3C) biosensor filled with polystyrene particles was proposed for online monitoring of the acute water toxicity. The peak current of the biosensor related with the performance of the bioanode was regarded as the toxicity indicator, and thus the acute water toxicity could be determined in terms of inhibition ratio by comparing the peak current obtained with water sample to that obtained with nontoxic standard water. The incorporation of polystyrene particles in the electrochemical cell not only reduced the volume of the samples used, but also improved the sensitivity of the biosensor. Experimental conditions including washing time with PBS and the concentration of sodium acetate solution were optimized. The stability of the M3C biosensor under optimal conditions was also investigated. The M3C biosensor was further examined by formaldehyde at the concentration of 0.01%, 0.03%, and 0.05% (v/v), and the corresponding inhibition ratios were 14.6%, 21.6%, and 36.4%, respectively. This work provides a new insight into the development of an online toxicity detector based on M3C biosensor.

From basic physics to mechanisms of toxicity: the ``liquid drop'' approach applied to develop predictive classification models for toxicity of metal oxide nanoparticles

Science.gov (United States)

Sizochenko, Natalia; Rasulev, Bakhtiyor; Gajewicz, Agnieszka; Kuz'min, Victor; Puzyn, Tomasz; Leszczynski, Jerzy

2014-10-01

Many metal oxide nanoparticles are able to cause persistent stress to live organisms, including humans, when discharged to the environment. To understand the mechanism of metal oxide nanoparticles' toxicity and reduce the number of experiments, the development of predictive toxicity models is important. In this study, performed on a series of nanoparticles, the comparative quantitative-structure activity relationship (nano-QSAR) analyses of their toxicity towards E. coli and HaCaT cells were established. A new approach for representation of nanoparticles' structure is presented. For description of the supramolecular structure of nanoparticles the ``liquid drop'' model was applied. It is expected that a novel, proposed approach could be of general use for predictions related to nanomaterials. In addition, in our study fragmental simplex descriptors and several ligand-metal binding characteristics were calculated. The developed nano-QSAR models were validated and reliably predict the toxicity of all studied metal oxide nanoparticles. Based on the comparative analysis of contributed properties in both models the LDM-based descriptors were revealed to have an almost similar level of contribution to toxicity in both cases, while other parameters (van der Waals interactions, electronegativity and metal-ligand binding characteristics) have unequal contribution levels. In addition, the models developed here suggest different mechanisms of nanotoxicity for these two types of cells.Many metal oxide nanoparticles are able to cause persistent stress to live organisms, including humans, when discharged to the environment. To understand the mechanism of metal oxide nanoparticles' toxicity and reduce the number of experiments, the development of predictive toxicity models is important. In this study, performed on a series of nanoparticles, the comparative quantitative-structure activity relationship (nano-QSAR) analyses of their toxicity towards E. coli and HaCaT cells were

Investigation of toxic influence of Ignalina NPP waste water on Spirodela polyrrhiza culture

International Nuclear Information System (INIS)

Lakachauskiene, R.; Marchiulioniene, D.

1995-01-01

The influence of Ignalina NPP waste waters and of water taken in different biotop of lake Drukshiai on Spirodela polyrrhiza culture (growth intensity, biomass and morphological changes) was investigated. It was revealed that most polluted waters formed by Ignalina NPP outcomes were from industrial - rain sewerage and economic - domestic waste waters. Toxicity of all investigated waters was higher in autumn (October) than it was in spring (March -April). Comparative analysis of the data obtained in 1992-1994 indicated the growing tendency of toxicity in Ignalina NPP waste waters as well as lake Drukshiai water. (author). 5 refs., 4 figs

Phytoremediation of wastewater toxicity using water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes).

Science.gov (United States)

Victor, Kouamé Kouamé; Séka, Yapoga; Norbert, Kouadio Kouakou; Sanogo, Tidou Abiba; Celestin, Atsé Boua

2016-10-02

This paper elucidates the phytoremediation potential of water hyacinth and water lettuce on the reduction of wastewater toxicity. Acute toxicity tests were performed in an aquarium with a population of Sarotherodon melanotheron, contaminated by different concentrations of wastewaters before and after phytoremediation with Eichhornia crassipes and Pistia stratiotes. Lethal concentrations (LC50) of the fish's population obtained during 24 hours of exposures were determined. COD, BOD, ammonium, TKN and PO4(3-) concentrations in wastewaters were of 1850.29, 973.33, 38.34, 61.49 and 39.23 mg L(-1), respectively, for each plant. Phytoremediation reduced 58.87% of ammonium content, 50.04% of PO4(3-), 82.45% of COD and 84.91% of BOD. After 15 days of the experiment, metal contents in treated wastewaters decreased from 6.65 to 97.56% for water hyacinth and 3.51 to 93.51% for water lettuce tanks. Toxicity tests showed that the mortality of fish exposed increased with increase in concentration of pollutants in wastewaters and the time of exposure. Therefore, the highest value of LC50 was recorded for fish subjected to 3 hours of exposure (16.37%). The lowest rate was obtained after an exposure of 20 to 24 hours (5.85%). After phytoremediation, the effluents purified by Eichhornia crassipes can maintain the fish life beyond 24 hours of exposure.

Predictive value of cell assays for developmental toxicity and embryotoxicity of conazole fungicides

DEFF Research Database (Denmark)

Sørensen, Karin Dreisig; Taxvig, Camilla; Kjærstad, Mia Birkhøj

2013-01-01

in reasonably good agreement with available in vivo effects. Ketoconazole and epoxiconazole are the most potent embryotoxic compounds, whereas prochloraz belongs to the most potent developmental toxicants. In conclusion, a rough prediction of the ranking of these conazole fungicides for in vivo toxicity data...

Water quality and toxicity of river water downstream of the uranium mining facility at Pocos de Caldas, MG, Brazil

International Nuclear Information System (INIS)

Lauria, Dejanira C.; Vascocnellos, Luisa M.H.; Simoes, Francisco F. Lamego; Clain, Almir F.; Scassiotti, Walter F.; Antunes, Ivan; Ferreira, Ana M.; Nascimento, Marcos R.L.

2009-01-01

The uranium mining site of Pocos de Caldas consists of open mine pit, tailings, waste rock dumps and an acid rock drainage problem, which has the potential to impact upon freshwater of the Ribeirao das Antas catchment. The high level of manganese (value of 1.8 mg/L) contained in the discharge water (DW) is an important factor affecting the water quality of the river (water quality criterion for aquatic life for Mn is 0.1 mg/L). Water quality criteria (WQC) are used for regulatory purpose and intended to define concentrations of chemicals in water that are protective of aquatic life and human health. WQC is a standard, although it is recognized that in some instances these criteria may be overprotective as metal bioavailability and hence toxicity is dependent on water chemistry. The toxicity assessment of WD was performed by bioassays with Daphnia similis and Ceriodaphnia dubia as bioindicators. As DW showed no toxicity to the organisms and the chemical analysis and dose assessments pointed U and Mn as the most important metals for water toxicity, the U and Mn toxicities were evaluated in the DW spiked with U and Mn. Acute uranium toxicity (48 h immobilisation test) for Daphnia similis was determined as a LC50 value (concentration that is toxic to 50% of test organisms) around 0.05-0.06 mg/L, value close to the one found for effects on reproduction, a 7 day LOEC (lowest observed effect concentration) of 0.062 mg/L for Ceriodaphnia dubia. The value of NOEC (no-observed effect concentration) for U was 0.03 mg U/L, which is higher than the concentration corresponded to the authorized dose limit for 238 U (0.004 mg/L) and higher than the uranium WQC (0.02 mg U/L). The manganese concentration in the DW is lower than the found value of LC50 (11.5 mg/L), LOEC (10 mg/L) and NOEC (5 mg Mn/L). (author)

Toxicity of common ions to marine organisms

International Nuclear Information System (INIS)

Pillard, D.A.; DuFresne, D.L.; Evans, J.

1995-01-01

Produced waters from oil and gas drilling operations are typically very saline, and these may cause acute toxicity to marine organisms due to osmotic imbalances as well as to an excess or deficiency of specific common ions. In order to better understand the relationship between toxicity and ion concentration, laboratory toxicity tests were conducted using mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside (Menidia beryllina). For each species the ionic concentration of standard laboratory water was proportionally increased or decreased to produce test solutions with a range of salinities. Organisms were exposed for 48 hours. Individual ions (sodium, potassium, calcium, magnetsium, strontium, chloride, bromide, sulfate, bicarbonate, and borate) were also manipulated to examine individual ion toxicity. The three test species differ in their tolerance of salinity. Mysid shrimp show a marked decrease in survival at salinities less than approximately 5 ppt. Both fish species tolerated low salinity water, however, silversides were less tolerant of saline waters (salinity greater than 40 ppt). There were also significant differences in the responses of the organisms to different ions. The results show that the salinity of the test solution may play an important role in the responses of the organisms to the produced water effluent. Predictable toxicity/ion relationships developed in this study can be used to estimate whether toxicity in a produced water is a result of common ions, salinity, or some other unknown toxicant

The utility of QSARs in predicting acute fish toxicity of pesticide metabolites: A retrospective validation approach.

Science.gov (United States)

Burden, Natalie; Maynard, Samuel K; Weltje, Lennart; Wheeler, James R

2016-10-01

The European Plant Protection Products Regulation 1107/2009 requires that registrants establish whether pesticide metabolites pose a risk to the environment. Fish acute toxicity assessments may be carried out to this end. Considering the total number of pesticide (re-) registrations, the number of metabolites can be considerable, and therefore this testing could use many vertebrates. EFSA's recent "Guidance on tiered risk assessment for plant protection products for aquatic organisms in edge-of-field surface waters" outlines opportunities to apply non-testing methods, such as Quantitative Structure Activity Relationship (QSAR) models. However, a scientific evidence base is necessary to support the use of QSARs in predicting acute fish toxicity of pesticide metabolites. Widespread application and subsequent regulatory acceptance of such an approach would reduce the numbers of animals used. The work presented here intends to provide this evidence base, by means of retrospective data analysis. Experimental fish LC50 values for 150 metabolites were extracted from the Pesticide Properties Database (http://sitem.herts.ac.uk/aeru/ppdb/en/atoz.htm). QSAR calculations were performed to predict fish acute toxicity values for these metabolites using the US EPA's ECOSAR software. The most conservative predicted LC50 values generated by ECOSAR were compared with experimental LC50 values. There was a significant correlation between predicted and experimental fish LC50 values (Spearman rs = 0.6304, p < 0.0001). For 62% of metabolites assessed, the QSAR predicted values are equal to or lower than their respective experimental values. Refined analysis, taking into account data quality and experimental variation considerations increases the proportion of sufficiently predictive estimates to 91%. For eight of the nine outliers, there are plausible explanation(s) for the disparity between measured and predicted LC50 values. Following detailed consideration of the robustness of

Large-scale assessment of the zebrafish embryo as a possible predictive model in toxicity testing.

Directory of Open Access Journals (Sweden)

Shaukat Ali

Full Text Available BACKGROUND: In the drug discovery pipeline, safety pharmacology is a major issue. The zebrafish has been proposed as a model that can bridge the gap in this field between cell assays (which are cost-effective, but low in data content and rodent assays (which are high in data content, but less cost-efficient. However, zebrafish assays are only likely to be useful if they can be shown to have high predictive power. We examined this issue by assaying 60 water-soluble compounds representing a range of chemical classes and toxicological mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Over 20,000 wild-type zebrafish embryos (including controls were cultured individually in defined buffer in 96-well plates. Embryos were exposed for a 96 hour period starting at 24 hours post fertilization. A logarithmic concentration series was used for range-finding, followed by a narrower geometric series for LC(50 determination. Zebrafish embryo LC(50 (log mmol/L, and published data on rodent LD(50 (log mmol/kg, were found to be strongly correlated (using Kendall's rank correlation tau and Pearson's product-moment correlation. The slope of the regression line for the full set of compounds was 0.73403. However, we found that the slope was strongly influenced by compound class. Thus, while most compounds had a similar toxicity level in both species, some compounds were markedly more toxic in zebrafish than in rodents, or vice versa. CONCLUSIONS: For the substances examined here, in aggregate, the zebrafish embryo model has good predictivity for toxicity in rodents. However, the correlation between zebrafish and rodent toxicity varies considerably between individual compounds and compound class. We discuss the strengths and limitations of the zebrafish model in light of these findings.

Influence of bioassay volume, water column height, and octanol-water partition coefficient on the toxicity of pesticides to rainbow trout.

Science.gov (United States)

Altinok, Ilhan; Capkin, Erol; Boran, Halis

2011-06-01

Effects of water volume and water column height on toxicity of cypermethrin, carbaryl, dichlorvos, tetradifon, maneb, captan, carbosulfan endosulfan and HgCl₂ to juvenile rainbow trout (Oncorhynchus mykiss, 3.2 ± 0.7 g) were evaluated in different glass aquaria under static conditions. When fish were exposed to the chemical compounds in 23 cm water column height (25 L), their mortality ranged between 0% and 58%. At the same water volume, but lower water column height (9 cm), mortality of fish increased significantly and was in a range from 60% to 95%. At the same water column height, toxic effects of chemicals were significantly higher in 25 L water volume than that of 8.5 L, water except maneb which has lowest (-0.45) octanol-water partition coefficient value. Mortality rates ratio of 9 and 23 cm water column height ranged between 1.12 and 90 while mortality rates ratio of 9 and 25 L water volume ranged between 1.20 and 4.0. Because actual exposure concentrations were not affected by either water volume or water column height, we propose that increased pesticides' toxicity was related to an increase in bioassay volume, since more pesticide molecules were able to interact with or accumulate the fish. However, there seem to be no relationship between the effects of water volume, water column height and Kow value of chemicals with regard to toxicity in juvenile rainbow trout.

Selection of a Battery of Rapid Toxicity Sensors for Drinking Water Evaluation

National Research Council Canada - National Science Library

van der Schalie, William H; James, Ryan R; Gargan, II., Thomas P

2006-01-01

.... Ten toxicity sensors utilizing enzymes, bacteria, or vertebrate cells were tested to determine the minimum number of sensors that could rapidly identify toxicity in water samples containing one of 12...

Effects of water chemistry on the dissolution of ZnO nanoparticles and their toxicity to Escherichia coli

International Nuclear Information System (INIS)

Li Mei; Lin Daohui; Zhu Lizhong

2013-01-01

The dissolution of ZnO nanoparticles (nano-ZnO) plays an important role in the toxicity of nano-ZnO to the aquatic organisms. The effects of water chemistry such as pH, ionic components, and dissolved organic matter (DOM) on the dissolution of nano-ZnO and its toxicity to Escherichia coli (E. coli) were investigated in synthetic and natural water samples. The results showed that the toxicity of nano-ZnO to E. coli depended on not only free Zn 2+ but also the coexisting cations which could reduce the toxicity of Zn 2+ . Increasing solution pH, HPO 4 2− , and DOM reduced the concentration of free Zn 2+ released from nano-ZnO, and thus lowered the toxicity of nano-ZnO. In addition, both Ca 2+ and Mg 2+ dramatically reduced the toxicity of Zn 2+ to E. coli. These results highlight the importance of water chemistry on the toxicity evaluation of nano-ZnO in natural waters. - Highlights: ► The effects of water chemistry on the toxicity of nano-ZnO were investigated. ► Increasing solution pH, HPO 4 2− , and DOM reduced nano-ZnO toxicity to E. coli. ► Ca 2+ and Mg 2+ could dramatically reduce the toxicity of nano-ZnO to E. coli. ► Free Zn 2+ ions and water hardness together controlled nano-ZnO toxicity in waters. - The toxicity of nano-ZnO to E. coli depended on not only free Zn 2+ but also Ca 2+ and Mg 2+ which could reduce the toxicity of Zn 2+ .

Investigating copper toxicity in the tropical fish cardinal tetra (Paracheirodon axelrodi) in natural Amazonian waters: Measurements, modeling, and reality

International Nuclear Information System (INIS)

Crémazy, Anne; Wood, Chris M.; Smith, D. Scott; Ferreira, Márcio S.; Johannsson, Ora E.; Giacomin, Marina; Val, Adalberto L.

2016-01-01

Highlights: • Copper toxicity to a tropical fish varied greatly in different Amazonian waters. • The biotic ligand model could not capture this variability. • Possible physiological protection was offered by natural organic matter. • Care must be used in applying BLM to fish in tropical waters. - Abstract: Copper at high concentrations is an ionoregulatory toxicant in fish and its toxicity is known to be strongly modulated by the water chemistry. The toxicity of Cu to the tropical fish cardinal tetra (Paracheirodon axelrodi) was investigated in waters from two major rivers of the Amazon watershed: the Rio Negro (filtered <0.45 μm, pH 5.6, DOC = 8.4 mg L"−"1, Na = 33 μM, Ca = 8 μM) and the Rio Solimões (filtered <0.45 μm, pH 6.7, DOC = 2.8 mg L"−"1, Na = 185 μM, Ca = 340 μM), as well as in a natural “reference water” (groundwater) which was almost DOC-free (pH 6.0, DOC = 0.34 mg L"−"1, Na = 53 μM, Ca = 5 μM). Acute 96-h mortality, Cu bioaccumulation and net flux rates of Na"+, Cl"−, K"+ and total ammonia were determined in P. axelrodi exposed in each water. Copper speciation in each water was determined by two thermodynamic models and by potentiometry, and its toxicity was predicted based on the biotic ligand model (BLM) framework. Our results indicate that high Na"+ loss is the main mode of toxic action of Cu in P. axelrodi, in accordance with general theory. Cardinal tetra showed a particularly high ability to tolerate Cu and to maintain Na"+ balance, similar to the ability of this and other endemic Rio Negro species to tolerate low pH and ion-poor conditions. Cu toxicity was lower in Rio Negro than in the other two waters tested, and the free [Cu"2"+] at the LC50, as determined by any of the three speciation methods tested, was approximately 10-fold higher. This variation could not be captured by a realistic set of BLM parameters. At least in part, this observation may be due to gill physiological alterations induced by the abundant

Investigating copper toxicity in the tropical fish cardinal tetra (Paracheirodon axelrodi) in natural Amazonian waters: Measurements, modeling, and reality

Energy Technology Data Exchange (ETDEWEB)

Crémazy, Anne, E-mail: acremazy@zoology.ubc.ca [Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Wood, Chris M. [Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Smith, D. Scott [Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 (Canada); Ferreira, Márcio S. [Laboratory of Ecophysiology and Molecular Evolution, National Institute for Amazonian Research, Manaus, AM (Brazil); Johannsson, Ora E.; Giacomin, Marina [Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Val, Adalberto L. [Laboratory of Ecophysiology and Molecular Evolution, National Institute for Amazonian Research, Manaus, AM (Brazil)

2016-11-15

Highlights: • Copper toxicity to a tropical fish varied greatly in different Amazonian waters. • The biotic ligand model could not capture this variability. • Possible physiological protection was offered by natural organic matter. • Care must be used in applying BLM to fish in tropical waters. - Abstract: Copper at high concentrations is an ionoregulatory toxicant in fish and its toxicity is known to be strongly modulated by the water chemistry. The toxicity of Cu to the tropical fish cardinal tetra (Paracheirodon axelrodi) was investigated in waters from two major rivers of the Amazon watershed: the Rio Negro (filtered <0.45 μm, pH 5.6, DOC = 8.4 mg L{sup −1}, Na = 33 μM, Ca = 8 μM) and the Rio Solimões (filtered <0.45 μm, pH 6.7, DOC = 2.8 mg L{sup −1}, Na = 185 μM, Ca = 340 μM), as well as in a natural “reference water” (groundwater) which was almost DOC-free (pH 6.0, DOC = 0.34 mg L{sup −1}, Na = 53 μM, Ca = 5 μM). Acute 96-h mortality, Cu bioaccumulation and net flux rates of Na{sup +}, Cl{sup −}, K{sup +} and total ammonia were determined in P. axelrodi exposed in each water. Copper speciation in each water was determined by two thermodynamic models and by potentiometry, and its toxicity was predicted based on the biotic ligand model (BLM) framework. Our results indicate that high Na{sup +} loss is the main mode of toxic action of Cu in P. axelrodi, in accordance with general theory. Cardinal tetra showed a particularly high ability to tolerate Cu and to maintain Na{sup +} balance, similar to the ability of this and other endemic Rio Negro species to tolerate low pH and ion-poor conditions. Cu toxicity was lower in Rio Negro than in the other two waters tested, and the free [Cu{sup 2+}] at the LC50, as determined by any of the three speciation methods tested, was approximately 10-fold higher. This variation could not be captured by a realistic set of BLM parameters. At least in part, this observation may be due to gill

A hypothetical model for predicting the toxicity of high aspect ratio nanoparticles (HARN)

Science.gov (United States)

Tran, C. L.; Tantra, R.; Donaldson, K.; Stone, V.; Hankin, S. M.; Ross, B.; Aitken, R. J.; Jones, A. D.

2011-12-01

The ability to predict nanoparticle (dimensional structures which are less than 100 nm in size) toxicity through the use of a suitable model is an important goal if nanoparticles are to be regulated in terms of exposures and toxicological effects. Recently, a model to predict toxicity of nanoparticles with high aspect ratio has been put forward by a consortium of scientists. The High aspect ratio nanoparticles (HARN) model is a platform that relates the physical dimensions of HARN (specifically length and diameter ratio) and biopersistence to their toxicity in biological environments. Potentially, this model is of great public health and economic importance, as it can be used as a tool to not only predict toxicological activity but can be used to classify the toxicity of various fibrous nanoparticles, without the need to carry out time-consuming and expensive toxicology studies. However, this model of toxicity is currently hypothetical in nature and is based solely on drawing similarities in its dimensional geometry with that of asbestos and synthetic vitreous fibres. The aim of this review is two-fold: (a) to present findings from past literature, on the physicochemical property and pathogenicity bioassay testing of HARN (b) to identify some of the challenges and future research steps crucial before the HARN model can be accepted as a predictive model. By presenting what has been done, we are able to identify scientific challenges and research directions that are needed for the HARN model to gain public acceptance. Our recommendations for future research includes the need to: (a) accurately link physicochemical data with corresponding pathogenicity assay data, through the use of suitable reference standards and standardised protocols, (b) develop better tools/techniques for physicochemical characterisation, (c) to develop better ways of monitoring HARN in the workplace, (d) to reliably measure dose exposure levels, in order to support future epidemiological

A hypothetical model for predicting the toxicity of high aspect ratio nanoparticles (HARN)

International Nuclear Information System (INIS)

Tran, C. L.; Tantra, R.; Donaldson, K.; Stone, V.; Hankin, S. M.; Ross, B.; Aitken, R. J.; Jones, A. D.

2011-01-01

The ability to predict nanoparticle (dimensional structures which are less than 100 nm in size) toxicity through the use of a suitable model is an important goal if nanoparticles are to be regulated in terms of exposures and toxicological effects. Recently, a model to predict toxicity of nanoparticles with high aspect ratio has been put forward by a consortium of scientists. The High aspect ratio nanoparticles (HARN) model is a platform that relates the physical dimensions of HARN (specifically length and diameter ratio) and biopersistence to their toxicity in biological environments. Potentially, this model is of great public health and economic importance, as it can be used as a tool to not only predict toxicological activity but can be used to classify the toxicity of various fibrous nanoparticles, without the need to carry out time-consuming and expensive toxicology studies. However, this model of toxicity is currently hypothetical in nature and is based solely on drawing similarities in its dimensional geometry with that of asbestos and synthetic vitreous fibres. The aim of this review is two-fold: (a) to present findings from past literature, on the physicochemical property and pathogenicity bioassay testing of HARN (b) to identify some of the challenges and future research steps crucial before the HARN model can be accepted as a predictive model. By presenting what has been done, we are able to identify scientific challenges and research directions that are needed for the HARN model to gain public acceptance. Our recommendations for future research includes the need to: (a) accurately link physicochemical data with corresponding pathogenicity assay data, through the use of suitable reference standards and standardised protocols, (b) develop better tools/techniques for physicochemical characterisation, (c) to develop better ways of monitoring HARN in the workplace, (d) to reliably measure dose exposure levels, in order to support future epidemiological

Characterizing toxicity of metal-contaminated sediments from mining areas

International Nuclear Information System (INIS)

Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.

2015-01-01

Highlights: • We review methods for testing toxicity of sediments affected by metals. • Toxicity testing provides site-specific assessment of impacts on resident biota. • Goals are to document extent of toxicity and associations with metal exposure. • Need to characterize bioavailability of metals in sediment and pore water. • Toxicity data is basis for guidelines used to predict hazards of metal toxicity. - Abstract: This paper reviews methods for testing the toxicity of metals associated with freshwater sediments, linking toxic effects with metal exposure and bioavailability, and developing sediment quality guidelines. The most broadly applicable approach for characterizing metal toxicity is whole-sediment toxicity testing, which attempts to simulate natural exposure conditions in the laboratory. Standard methods for whole-sediment testing can be adapted to test a wide variety of taxa. Chronic sediment tests that characterize effects on multiple endpoints (e.g., survival, growth, and reproduction) can be highly sensitive indicators of adverse effects on resident invertebrate taxa. Methods for testing of aqueous phases (pore water, overlying water, or elutriates) are used less frequently. Analysis of sediment toxicity data focuses on statistical comparisons between responses in sediments from the study area and responses in one or more uncontaminated reference sediments. For large or complex study areas, a greater number of reference sediments is recommended to reliably define the normal range of responses in uncontaminated sediments – the ‘reference envelope’. Data on metal concentrations and effects on test organisms across a gradient of contamination may allow development of concentration-response models, which estimate metal concentrations associated with specified levels of toxic effects (e.g. 20% effect concentration or EC20). Comparisons of toxic effects in laboratory tests with measures of impacts on resident benthic invertebrate

Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

Science.gov (United States)

Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

2014-10-21

Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

NMR-based urine analysis in rats: prediction of proximal tubule kidney toxicity and phospholipidosis.

Science.gov (United States)

Lienemann, Kai; Plötz, Thomas; Pestel, Sabine

2008-01-01

The aim of safety pharmacology is early detection of compound-induced side-effects. NMR-based urine analysis followed by multivariate data analysis (metabonomics) identifies efficiently differences between toxic and non-toxic compounds; but in most cases multiple administrations of the test compound are necessary. We tested the feasibility of detecting proximal tubule kidney toxicity and phospholipidosis with metabonomics techniques after single compound administration as an early safety pharmacology approach. Rats were treated orally, intravenously, inhalatively or intraperitoneally with different test compounds. Urine was collected at 0-8 h and 8-24 h after compound administration, and (1)H NMR-patterns were recorded from the samples. Variation of post-processing and feature extraction methods led to different views on the data. Support Vector Machines were trained on these different data sets and then aggregated as experts in an Ensemble. Finally, validity was monitored with a cross-validation study using a training, validation, and test data set. Proximal tubule kidney toxicity could be predicted with reasonable total classification accuracy (85%), specificity (88%) and sensitivity (78%). In comparison to alternative histological studies, results were obtained quicker, compound need was reduced, and very importantly fewer animals were needed. In contrast, the induction of phospholipidosis by the test compounds could not be predicted using NMR-based urine analysis or the previously published biomarker PAG. NMR-based urine analysis was shown to effectively predict proximal tubule kidney toxicity after single compound administration in rats. Thus, this experimental design allows early detection of toxicity risks with relatively low amounts of compound in a reasonably short period of time.

Evaluation of Ignalina NPP waste waters toxicity by use of biotest complex

International Nuclear Information System (INIS)

Marchiulioniene, D.

1995-01-01

The impact of lake Drukshiai various biotop waters and bottom sediments on test-organisms Tradescantia higher plants, as well as trout Salmo gairdneri spawn and larvae was investigated in 1988 - 1994. It was determined that toxic matters, heavy metals and radionuclides among them, discharge into lake Drukshiai with Ignalina NPP waste waters. They accumulate in components of ecosystem, especially in bottom sediments. The gradual increase of toxic impact caused by water and bottom sediments is observed in the investigated lake biotops. The highest toxity levels were in 1993. Maximal toxity is caused by chemical matters. (author). 11 refs., 4 tabs., 3 figs

Prediction of toxicity of nitrobenzenes using ab initio and least squares support vector machines

International Nuclear Information System (INIS)

Niazi, Ali; Jameh-Bozorghi, Saeed; Nori-Shargh, Davood

2008-01-01

A quantitative structure-property relationship (QSPR) study is suggested for the prediction of toxicity (IGC 50 ) of nitrobenzenes. Ab initio theory was used to calculate some quantum chemical descriptors including electrostatic potentials and local charges at each atom, HOMO and LUMO energies, etc. Modeling of the IGC 50 of nitrobenzenes as a function of molecular structures was established by means of the least squares support vector machines (LS-SVM). This model was applied for the prediction of the toxicity (IGC 50 ) of nitrobenzenes, which were not in the modeling procedure. The resulted model showed high prediction ability with root mean square error of prediction of 0.0049 for LS-SVM. Results have shown that the introduction of LS-SVM for quantum chemical descriptors drastically enhances the ability of prediction in QSAR studies superior to multiple linear regression and partial least squares

Predicting the risk of toxic blooms of golden alga from cell abundance and environmental covariates

Science.gov (United States)

Patino, Reynaldo; VanLandeghem, Matthew M.; Denny, Shawn

2016-01-01

Golden alga (Prymnesium parvum) is a toxic haptophyte that has caused considerable ecological damage to marine and inland aquatic ecosystems worldwide. Studies focused primarily on laboratory cultures have indicated that toxicity is poorly correlated with the abundance of golden alga cells. This relationship, however, has not been rigorously evaluated in the field where environmental conditions are much different. The ability to predict toxicity using readily measured environmental variables and golden alga abundance would allow managers rapid assessments of ichthyotoxicity potential without laboratory bioassay confirmation, which requires additional resources to accomplish. To assess the potential utility of these relationships, several a priori models relating lethal levels of golden alga ichthyotoxicity to golden alga abundance and environmental covariates were constructed. Model parameters were estimated using archived data from four river basins in Texas and New Mexico (Colorado, Brazos, Red, Pecos). Model predictive ability was quantified using cross-validation, sensitivity, and specificity, and the relative ranking of environmental covariate models was determined by Akaike Information Criterion values and Akaike weights. Overall, abundance was a generally good predictor of ichthyotoxicity as cross validation of golden alga abundance-only models ranged from ∼ 80% to ∼ 90% (leave-one-out cross-validation). Environmental covariates improved predictions, especially the ability to predict lethally toxic events (i.e., increased sensitivity), and top-ranked environmental covariate models differed among the four basins. These associations may be useful for monitoring as well as understanding the abiotic factors that influence toxicity during blooms.

Film mass transfer coefficient for the prediction of volatile organic compound evaporation rate from open water basin

OpenAIRE

Charun Bunyakan; Preyaporn Tongsoi; Chakrit Tongurai

2001-01-01

The evaporation of volatile organic compounds(VOCs) from treatment, storage, disposal facility(TSDF) is an important air pollution issue because of the evaporation quantity and toxicity and/or carcinogenicity. This paper concerns VOC evaporation from open water basins such as the equalization basin and nonaerate surface impoundments in a wastewater treatment plant. The amount of VOCs evaporation from open water basins can be predicted by using the two-film model that requires two mass transfe...

Modeling Aquatic Toxicity through Chromatographic Systems.

Science.gov (United States)

Fernández-Pumarega, Alejandro; Amézqueta, Susana; Farré, Sandra; Muñoz-Pascual, Laura; Abraham, Michael H; Fuguet, Elisabet; Rosés, Martí

2017-08-01

Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.

Copper bioavailability and toxicity to Mytilus galloprovincialis in Shelter Island Yacht Basin, San Diego, CA.

Science.gov (United States)

Bosse, Casey; Rosen, Gunther; Colvin, Marienne; Earley, Patrick; Santore, Robert; Rivera-Duarte, Ignacio

2014-08-15

The bioavailability and toxicity of copper (Cu) in Shelter Island Yacht Basin (SIYB), San Diego, CA, USA, was assessed with simultaneous toxicological, chemical, and modeling approaches. Toxicological measurements included laboratory toxicity testing with Mytilus galloprovincialis (Mediterranean mussel) embryos added to both site water (ambient) and site water spiked with multiple Cu concentrations. Chemical assessment of ambient samples included total and dissolved Cu concentrations, and Cu complexation capacity measurements. Modeling was based on chemical speciation and predictions of bioavailability and toxicity using a marine Biotic Ligand Model (BLM). Cumulatively, these methods assessed the natural buffering capacity of Cu in SIYB during singular wet and dry season sampling events. Overall, the three approaches suggested negligible bioavailability, and isolated observed or predicted toxicity, despite an observed gradient of increasing Cu concentration, both horizontally and vertically within the water body, exceeding current water quality criteria for saltwater. Published by Elsevier Ltd.

Predicting cyanobacterial abundance, microcystin, and geosmin in a eutrophic drinking-water reservoir using a 14-year dataset

Science.gov (United States)

Harris, Ted D.; Graham, Jennifer L.

2017-01-01

Cyanobacterial blooms degrade water quality in drinking water supply reservoirs by producing toxic and taste-and-odor causing secondary metabolites, which ultimately cause public health concerns and lead to increased treatment costs for water utilities. There have been numerous attempts to create models that predict cyanobacteria and their secondary metabolites, most using linear models; however, linear models are limited by assumptions about the data and have had limited success as predictive tools. Thus, lake and reservoir managers need improved modeling techniques that can accurately predict large bloom events that have the highest impact on recreational activities and drinking-water treatment processes. In this study, we compared 12 unique linear and nonlinear regression modeling techniques to predict cyanobacterial abundance and the cyanobacterial secondary metabolites microcystin and geosmin using 14 years of physiochemical water quality data collected from Cheney Reservoir, Kansas. Support vector machine (SVM), random forest (RF), boosted tree (BT), and Cubist modeling techniques were the most predictive of the compared modeling approaches. SVM, RF, and BT modeling techniques were able to successfully predict cyanobacterial abundance, microcystin, and geosmin concentrations <60,000 cells/mL, 2.5 µg/L, and 20 ng/L, respectively. Only Cubist modeling predicted maxima concentrations of cyanobacteria and geosmin; no modeling technique was able to predict maxima microcystin concentrations. Because maxima concentrations are a primary concern for lake and reservoir managers, Cubist modeling may help predict the largest and most noxious concentrations of cyanobacteria and their secondary metabolites.

Ground and surface water developmental toxicity at a municipal landfill--Description and weather-related variation

Science.gov (United States)

Bruner, M.A.; Rao, M.; Dumont, J.N.; Hull, M.; Jones, T.; Bantle, J.A.

1998-01-01

Contaminated groundwater poses a significant health hazard and may also impact wildlife such as amphibians when it surfaces. Using FETAX (Frog Embryo Teratogenesis Assay-Xenopus), the developmental toxicity of ground and surface water samples near a closed municipal landfill at Norman, OK, were evaluated. The groundwater samples were taken from a network of wells in a shallow, unconfined aquifer downgradient from the landfill. Surface water samples were obtained from a pond and small stream adjacent to the landfill. Surface water samples from a reference site in similar habitat were also analyzed. Groundwater samples were highly toxic in the area near the landfill, indicating a plume of toxicants. Surface water samples from the landfill site demonstrated elevated developmental toxicity. This toxicity was temporally variable and was significantly correlated with weather conditions during the 3 days prior to sampling. Mortality was negatively correlated with cumulative rain and relative humidity. Mortality was positively correlated with solar radiation and net radiation. No significant correlations were observed between mortality and weather parameters for days 4–7 preceding sampling.

Observed and predicted reproduction of Ceriodaphnia dubia exposed to chloride, sulfate, and bicarbonate

Science.gov (United States)

Lasier, Peter J.; Hardin, Ian R.

2010-01-01

Chronic toxicities of Cl-, SO42-, and HCO3- to Ceriodaphnia dubia were evaluated in low- and moderate-hardness waters using a three-brood reproduction test method. Toxicity tests of anion mixtures were used to determine interaction effects and to produce models predicting C. dubia reproduction. Effluents diluted with low- and moderate-hardness waters were tested with animals acclimated to low- and moderate-hardness conditions to evaluate the models and to assess the effects of hardness and acclimation. Sulfate was significantly less toxic than Cl- and HCO3- in both types of water. Chloride and HCO3- toxicities were similar in low-hardness water, but HCO3- was the most toxic in moderate-hardness water. Low acute-to-chronic ratios indicate that toxicities of these anions will decrease quickly with dilution. Hardness significantly reduced Cl- and SO42- toxicity but had little effect on HCO3-. Chloride toxicity decreased with an increase in Na+ concentration, and CO3- toxicity may have been reduced by the dissolved organic carbon in effluent. Multivariate models using measured anion concentrations in effluents with low to moderate hardness levels provided fairly accurate predictions of reproduction. Determinations of toxicity for several effluents differed significantly depending on the hardness of the dilution water and the hardness of the water used to culture test animals. These results can be used to predict the contribution of elevated anion concentrations to the chronic toxicity of effluents; to identify effluents that are toxic due to contaminants other than Cl-, SO42-, and HCO3-; and to provide a basis for chemical substitutions in manufacturing processes.

How to accurately assay the algal toxicity of pesticides with low water solubility

International Nuclear Information System (INIS)

Ma Jianyi; Chen Jianmeng

2005-01-01

A novel method for assaying and calculating the toxicity of water-insoluble pesticides to green algae has been put forward in this work. First, a solvent is selected for use in bioassays; there should be a detailed screening to identify a solvent with inherently low toxicity to the test organism. Second, the EC 50 is determined for selected pesticides by measuring the toxicity of various concentrations of each of the selected pesticides in a fixed concentration of selected solvent. Third, concentrations of the selected solvent are varied and the EC 50 of each pesticide tested is assayed at a fixed concentration. Fourth, several suitable groups of solvent concentrations are selected and the corresponding EC 50 values of tested pesticides are considered to establish the linear regression equation. Letting the solvent concentration be zero, one calculates the corresponding EC 50 value, which corresponds to the inherent toxicity of the tested pesticide. - A new method is described for assaying the toxicity of water insoluble pesticides

Toxicity of acid mine pit lake water remediated with limestone and phosphorus

Energy Technology Data Exchange (ETDEWEB)

Neil, L.L.; McCullough, C.D.; Lund, M.A.; Evans, L.H.; Tsvetnenko, Y. [Edith Cowan University, Joondalup, WA (Australia)

2009-11-15

Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH similar to 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

Toxicity of acid mine pit lake water remediated with limestone and phosphorus.

Science.gov (United States)

Neil, Luke L; McCullough, Clint D; Lund, Mark A; Evans, Louis H; Tsvetnenko, Yuri

2009-11-01

Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH approximately 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and (c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

Prediction of Acute Mammalian Toxicity Using QSAR Methods: A Case Study of Sulfur Mustard and Its Breakdown Products

Directory of Open Access Journals (Sweden)

John Wheeler

2012-07-01

Full Text Available Predicting toxicity quantitatively, using Quantitative Structure Activity Relationships (QSAR, has matured over recent years to the point that the predictions can be used to help identify missing comparison values in a substance’s database. In this manuscript we investigate using the lethal dose that kills fifty percent of a test population (the LD₅₀ for determining relative toxicity of a number of substances. In general, the smaller the LD₅₀ value, the more toxic the chemical, and the larger the LD₅₀ value, the lower the toxicity. When systemic toxicity and other specific toxicity data are unavailable for the chemical(s of interest, during emergency responses, LD₅₀ values may be employed to determine the relative toxicity of a series of chemicals. In the present study, a group of chemical warfare agents and their breakdown products have been evaluated using four available rat oral QSAR LD₅₀ models. The QSAR analysis shows that the breakdown products of Sulfur Mustard (HD are predicted to be less toxic than the parent compound as well as other known breakdown products that have known toxicities. The QSAR estimated break down products LD₅₀ values ranged from 299 mg/kg to 5,764 mg/kg. This evaluation allows for the ranking and toxicity estimation of compounds for which little toxicity information existed; thus leading to better risk decision making in the field.

Water resources assessment and prediction in China

Directory of Open Access Journals (Sweden)

W. Guangsheng

2016-10-01

Full Text Available Water resources assessment in China, can be classified into three groups: (i comprehensive water resources assessment, (ii annual water resources assessment, and (iii industrial project water resources assessment. Comprehensive water resources assessment is the conventional assessment where the frequency distribution of water resources in basins or provincial regions are analyzed. For the annual water resources assessment, water resources of the last year in basins or provincial regions are usually assessed. For the industrial project water resources assessment, the water resources situation before the construction of industrial project has to be assessed. To address the climate and environmental changes, hydrological and statistical models are widely applied for studies on assessing water resources changes. For the water resources prediction in China usually the monthly runoff prediction is used. In most low flow seasons, the flow recession curve is commonly used as prediction method. In the humid regions, the rainfall-runoff ensemble prediction (ESP has been widely applied for the monthly runoff prediction. The conditional probability method for the monthly runoff prediction was also applied to assess next month runoff probability under a fixed initial condition.

Acute and chronic toxicity of effluent water from an abandoned uranium mine.

Science.gov (United States)

Antunes, S C; Pereira, R; Gonçalves, F

2007-08-01

Inactive or abandoned mines represent a significant source of environmental, chemical, physical, and aesthetic impact. Among concerning situations, the occurrence of abandoned or semi-abandoned mine-associated ponds (for sedimentation of solids, for effluent neutralization, or for washing the ore) is a common feature in this type of system. These ponds are a source of contamination for the groundwater resources and adjacent soils, because they lack appropriate impermeabilization. The use of this water for agriculture may also pose chronic risks to humans. In Portugal, these problems have been diagnosed and some remediation projects have been developed. The purpose of our study was to evaluate the acute and chronic toxicity of water samples collected from the aquatic system surrounding an abandoned uranium mine (Cunha Baixa, Mangualde, Central Portugal). The present study focuses on the water compartment, whose toxicity was evaluated by means of standard toxicity assays using two Daphnia species (D. longispina and D. magna). Three different ponds were used in the characterization of the aquatic system from Cunha Baixa mine: a reference pond (Ref), a mine effluent treatment pond (T), and a mine pit pond (M). Metal analyses performed in the water samples from these ponds showed values that, in some cases, were much higher than maximum recommendable values established (especially Al, Mn) by Portuguese legislation for waters for crop irrigation. Acute toxicity was only observed in the mine pit pond, with EC(50) values of 28.4% and 50.4% for D. longispina and D. magna, respectively. The significant impairment of chronic endpoints, translated in reductions in the population growth rate for both species, gives rise to concerns regarding the potential risks for aquatic zooplanktonic communities, from local receiving waters, potentially exposed to point source discharges of the treated and nontreated effluent from Cunha Baixa uranium mine.

Development of Low-Toxicity Wastewater Stabilization for Spacecraft Water Recovery Systems

Science.gov (United States)

Adam, Niklas; Mitchell, Julie; Pickering, Karen; Carrier, Chris; Vega, Letty; Muirhead, Dean

2014-01-01

Wastewater stabilization was an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater was two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort was to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-mL volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

Insecticide toxicity to Hyalella curvispina in runoff and stream water within a soybean farm (Buenos Aires, Argentina).

Science.gov (United States)

Mugni, H; Ronco, A; Bonetto, C

2011-03-01

Toxicity to the locally dominant amphipod Hyalella curvispina was assessed in a first-order stream running through a cultivated farm. Cypermethrin, chlorpyrifos, endosulfan and glyphosate were sprayed throughout the studied period. Toxicity was assayed under controlled laboratory conditions with runoff and stream water samples taken from the field under steady state and flood conditions. Ephemeral toxicity pulses were observed as a consequence of farm pesticide applications. After pesticide application, runoff water showed 100% mortality to H. curvispina for 1 month, but no mortality thereafter. Toxicity persistence was shortest in stream water, intermediate in stream sediments and longest in soil samples. Runoff had a more important toxicity effect than the exposure to direct aerial fumigation. The regional environmental features determining fast toxicity dissipation are discussed. Copyright © 2010. Published by Elsevier Inc.

Predicting Pulmonary O2 Toxicity: A New Look at the Unit Pulmonary Toxicity Dose

Science.gov (United States)

1985-05-01

beatl loeged# aNy ahepes in Vo was considered error. The assumptieo was shoe eapeova to a 10 below the "safe’! I02 should have produced se daeromeat...Naval Medical Research Institute SethesdolMO 20814-505b NMRI 86-52 December 1986 PREDICTING4 PULMONARY 0 2 TOXICITY: j k,, NEW LOOK AT THE UNIT...distribution is unlimited °Q0- C(-" Naval Medical Research LLj and Development Command ,, J Bethesda, Maryland 20814-5044 -4 • Department of the Navy Naval

Using Rainbow Trout to Measure Arsenic Toxicity in Water

Directory of Open Access Journals (Sweden)

Kazem Naddafi

2006-06-01

Full Text Available The purpose of this study is to determine arsenic toxicity on rainbow trout. Acute toxicity of arsenic was determined by measuring the lethal effects on rainbow trout in static conditions. Five aquariums of 25×30×30 cm with five concentrations of 5,10,15,20 and 25 mg/L of arsenic were prepared and then ten fishes were added to each concentration. Also one aquarium with similar conditions was considered as a control with no arsenic solution. Hardness, temperature and dissolved oxygen of dilution water were determined by standard methods, and concentration of dissolved oxygen, pH and temperature of solution test in time periods of 2,4,6,8,24,48,72 and 96 hrs were measured. Water temperature of aquarium was regulated by circulation of water in refrigerator through indirect conduction with solution test. LC50 was measured at intervals of 24,48,72 and 96 hrs by SPSS software and respectively showed 28.13,21.77,15.78 and 12.72 mg/L.Probit curve was drawn by Harvard Chart XL software, and LC50 curve was drawn by Excel software.

Contribution of waste water treatment plants to pesticide toxicity in agriculture catchments.

Science.gov (United States)

Le, Trong Dieu Hien; Scharmüller, Andreas; Kattwinkel, Mira; Kühne, Ralph; Schüürmann, Gerrit; Schäfer, Ralf B

2017-11-01

Pesticide residues are frequently found in water bodies and may threaten freshwater ecosystems and biodiversity. In addition to runoff or leaching from treated agricultural fields, pesticides may enter streams via effluents from wastewater treatment plants (WWTPs). We compared the pesticide toxicity in terms of log maximum Toxic Unit (log mTU) of sampling sites in small agricultural streams of Germany with and without WWTPs in the upstream catchments. We found an approximately half log unit higher pesticide toxicity for sampling sites with WWTPs (p pesticide toxicity in streams with WWTPs. A few compounds (diuron, terbuthylazin, isoproturon, terbutryn and Metazachlor) dominated the herbicide toxicity. Pesticide toxicity was not correlated with upstream distance to WWTP (Spearman's rank correlation, rho = - 0.11, p > 0.05) suggesting that other context variables are more important to explain WWTP-driven pesticide toxicity. Our results suggest that WWTPs contribute to pesticide toxicity in German streams. Copyright © 2017 Elsevier Inc. All rights reserved.

Deep convolutional neural network with transfer learning for rectum toxicity prediction in cervical cancer radiotherapy: a feasibility study

Science.gov (United States)

Zhen, Xin; Chen, Jiawei; Zhong, Zichun; Hrycushko, Brian; Zhou, Linghong; Jiang, Steve; Albuquerque, Kevin; Gu, Xuejun

2017-11-01

Better understanding of the dose-toxicity relationship is critical for safe dose escalation to improve local control in late-stage cervical cancer radiotherapy. In this study, we introduced a convolutional neural network (CNN) model to analyze rectum dose distribution and predict rectum toxicity. Forty-two cervical cancer patients treated with combined external beam radiotherapy (EBRT) and brachytherapy (BT) were retrospectively collected, including twelve toxicity patients and thirty non-toxicity patients. We adopted a transfer learning strategy to overcome the limited patient data issue. A 16-layers CNN developed by the visual geometry group (VGG-16) of the University of Oxford was pre-trained on a large-scale natural image database, ImageNet, and fine-tuned with patient rectum surface dose maps (RSDMs), which were accumulated EBRT  +  BT doses on the unfolded rectum surface. We used the adaptive synthetic sampling approach and the data augmentation method to address the two challenges, data imbalance and data scarcity. The gradient-weighted class activation maps (Grad-CAM) were also generated to highlight the discriminative regions on the RSDM along with the prediction model. We compare different CNN coefficients fine-tuning strategies, and compare the predictive performance using the traditional dose volume parameters, e.g. D 0.1/1/2cc, and the texture features extracted from the RSDM. Satisfactory prediction performance was achieved with the proposed scheme, and we found that the mean Grad-CAM over the toxicity patient group has geometric consistence of distribution with the statistical analysis result, which indicates possible rectum toxicity location. The evaluation results have demonstrated the feasibility of building a CNN-based rectum dose-toxicity prediction model with transfer learning for cervical cancer radiotherapy.

Influence of ammonia on forming the toxicity of waters from the surface sources of water supply determined on Carassius auratus gibelio (Bloch, 1782

Directory of Open Access Journals (Sweden)

Е. Arystarkhova

2018-03-01

Full Text Available Purpose. Determination of the influence of ammonia in waters from surface sources of water supply of Zhytomyr city on forming the toxicity of these waters determined by test-reactions of atypical motor activity of Carassius auratus gibelio (Bloch, 1782 with the use of the «time sampling» method during 2012–2014. Methodology. Biotesting was performed at the Municipal Enterprise "Zhytomyrvodokanal". Water samples were taken once a month time from the Teteriv river reservoirs and tap water network and then placed into aquaria (8 dm3 on a group. Control and experimental groups of fish were formed according to the following scheme: control group — samples of settled (24 hours tap water; experimental group D-1 — water samples from the Denyshivske reservoir; experimental group D-2 — water samples from the Vidsichne water intake. Test specimens were females of C. auratus gibelio. Biotesting was conducted using the «time sampling» method by keeping fish (n=30 in water for 12 hours. The toxicity indexes of waters were calculated on the basis of the following test-reactions: spiral-like and vector movements, jumping out from water, immobilization and death of fish. Statistical processing of study results were performed using cross-correlation and regression analysis in MS Excel 2007 and Statistica-6. Findings. The study showed an effect of ammonia on the toxicity of waters from reservoirs of the Teteriv river that was determined by atypical motor activity with the use of the «time sampling» method, which consisted in the instantaneous fixation of the number of individuals that favored one or another act of behavior. It was shown that females not adapted to the action of ammonia reacted to its concentration in water of more than 0.55 mg/dm3 by disorders in movements. Unlike fish of experience groups, only single pathological acts were observed in the control group. A positive moderate relationship, which had a tendency to an increase, was

Predicting competitive adsorption behavior of major toxic anionic elements onto activated alumina: A speciation-based approach

International Nuclear Information System (INIS)

Su Tingzhi; Guan Xiaohong; Tang Yulin; Gu Guowei; Wang Jianmin

2010-01-01

Toxic anionic elements such as arsenic, selenium, and vanadium often co-exist in groundwater. These elements may impact each other when adsorption methods are used to remove them. In this study, we investigated the competitive adsorption behavior of As(V), Se(IV), and V(V) onto activated alumina under different pH and surface loading conditions. Results indicated that these anionic elements interfered with each other during adsorption. A speciation-based model was developed to quantify the competitive adsorption behavior of these elements. This model could predict the adsorption data well over the pH range of 1.5-12 for various surface loading conditions, using the same set of adsorption constants obtained from single-sorbate systems. This model has great implications in accurately predicting the field capacity of activated alumina under various local water quality conditions when multiple competitive anionic elements are present.

Strains of toxic and harmful microalgae, from waste water, marine, brackish and fresh water.

Science.gov (United States)

Rodríguez-Palacio, M C; Crisóstomo-Vázquez, L; Alvarez-Hernández, S; Lozano-Ramírez, C

2012-01-01

Some microalgae are economically important in Mexico and the world because they can be potentially toxic. Algal explosive population growths are named harmful algal blooms and are frequently recorded in Mexico. The authors set up potentially toxic microalgae cultures from the Gulf of Mexico (Garrapatas tideland, Barberena river, Carpintero lagoon in Tamaulipas State; Chalchoapan and Catemaco lakes in Veracruz State), from the Mexican Pacific Ocean, Guerrero, Colima and Michoacán States, and from interior water bodies such as Vicente Aguirre dam, Chapultepec lake and several waste water treatment plants. This research is about the diversity and abundance of phytoplankton in relation a specific site because of harmful algal bloom events. Microalgae cultures are useful in order to solve taxonomic problems, to know life cycles, molecular studies, for the study of toxic species, and the isolation of useful metabolites. The cultures for this research are clonal, non-axenic, semi-continuous, 12:12 light/dark photoperiod, 20 ± 1 °C temperature and 90.5 µmol m(-2)s(-1) illumination. Four different culture media were used. This collection is open to the worldwide scientific community as a source of organisms in controlled conditions that can be used as a useful tool for microalgae research work.

Dosimetric factors predictive of late toxicity in prostate cancer radiotherapy; Radiotherapie prostatique: prediction de la toxicite tardive a partir des donnees dosimetriques

Energy Technology Data Exchange (ETDEWEB)

Crevoisier, R. de [Departement de radiotherapie, centre Eugene-Marquis, 35 - Rennes (France); Inserm, U 642, 35 - Rennes (France); Fiorino, C. [Medical Physics Department, San Raffaele Scientific Institute, Melghera, Milan (Italy); Dubray, B. [Departement de radiotherapie et de physique medicale, centre Henri-Becquerel, 76 - Rouen (France); EA 4108, UFR de medecine-pharmacie, QuantIF-LITIS, 76 - Rouen (France)

2010-10-15

Dose escalation in prostate cancer is made possible due to technological advances and to precise dose-volume constraints to limit normal tissue damage. This article is a literature review focusing on the correlations between exposure (doses and volumes) of organs at risk (OAR) and rectal, urinary, sexual and bone toxicity, as well as on mathematical models aiming at toxicity prediction. Dose-volume constraint recommendations are presented that have been shown to be associated with reduced rectal damage. Indeed, the clinical data is relatively strong for late rectal toxicity (bleeding), with constraints put on both the volume of the rectum receiving high doses ({>=}70 Gy) and the volume receiving intermediate doses (40 to 60 Gy). Predictive models of rectal toxicity (Normal Tissue Complication Probability) appear to accurately estimate toxicity risks. The correlations are much weaker for the bulb and the femoral heads, and nearly do not exist for the bladder. Further prospective studies are required, ideally taking into account patient-related risk factors (co-morbidities and their specific treatments), assays of normal tissue hypersensitivity to ionizing radiation and mathematical models applied on 3D images acquired under the treatment machine (e.g. Cone Beam CT). (authors)

Predicted risks of radiogenic cardiac toxicity in two pediatric patients undergoing photon or proton radiotherapy

International Nuclear Information System (INIS)

Zhang, Rui; Howell, Rebecca M; Homann, Kenneth; Giebeler, Annelise; Taddei, Phillip J; Mahajan, Anita; Newhauser, Wayne D

2013-01-01

Hodgkin disease (HD) and medulloblastoma (MB) are common malignancies found in children and young adults, and radiotherapy is part of the standard treatment. It was reported that these patients who received radiation therapy have an increased risk of cardiovascular late effects. We compared the predicted risk of developing radiogenic cardiac toxicity after photon versus proton radiotherapies for a pediatric patient with HD and a pediatric patient with MB. In the treatment plans, each patient’s heart was contoured in fine detail, including substructures of the pericardium and myocardium. Risk calculations took into account both therapeutic and stray radiation doses. We calculated the relative risk (RR) of cardiac toxicity using a linear risk model and the normal tissue complication probability (NTCP) values using relative seriality and Lyman models. Uncertainty analyses were also performed. The RR values of cardiac toxicity for the HD patient were 7.27 (proton) and 8.37 (photon), respectively; the RR values for the MB patient were 1.28 (proton) and 8.39 (photon), respectively. The predicted NTCP values for the HD patient were 2.17% (proton) and 2.67% (photon) for the myocardium, and were 2.11% (proton) and 1.92% (photon) for the whole heart. The predicted ratios of NTCP values (proton/photon) for the MB patient were much less than unity. Uncertainty analyses revealed that the predicted ratio of risk between proton and photon therapies was sensitive to uncertainties in the NTCP model parameters and the mean radiation weighting factor for neutrons, but was not sensitive to heart structure contours. The qualitative findings of the study were not sensitive to uncertainties in these factors. We conclude that proton and photon radiotherapies confer similar predicted risks of cardiac toxicity for the HD patient in this study, and that proton therapy reduced the predicted risk for the MB patient in this study

Evaluation of water column and sediment toxicity from an abandoned uranium mine using a battery of bioassays

International Nuclear Information System (INIS)

Antunes, S.C.; Figueiredo, D.R. de; Marques, S.M.; Castro, B.B.; Pereira, R.; Goncalves, F.

2007-01-01

Uranium mining activities in Cunha Baixa, Mangualde (Portugal), were extensive between 1967 and 1993, with high production of poor ore. Ore exploitation left millions of tons of tailings in the surrounding area, close to human houses. Contamination of the area (water and soil compartment) presently represents a serious hazard to humans and wildlife. The aim of this work was to evaluate the acute toxicity of water and sediments from a pond that floods a uranium mine pit, in two periods (spring and autumn). High contents of metals were found in water samples (chiefly Mn, Fe, Al, U, Sr). A battery of assays was applied to screen the acute toxicity of the different compartments using algae, crustaceans and dipterans. Results showed that the sediments were non-toxic, unlike the superficial water. Water toxicity was higher in the autumn, when the effluent was more acidic, compared to spring. In the water toxicity assays, the relative sensitivity of the test species used was Daphnia longispina > Pseudokirchneriella subcapitata > Daphnia magna. The present study is part of the chemical and ecotoxicological characterisation of the aquatic compartment performed in the Tier 1 of the Ecological Risk Assessment of the Cunha Baixa mining area

Toxicity prediction of ionic liquids based on Daphnia magna by using density functional theory

Science.gov (United States)

Nu’aim, M. N.; Bustam, M. A.

2018-04-01

By using a model called density functional theory, the toxicity of ionic liquids can be predicted and forecast. It is a theory that allowing the researcher to have a substantial tool for computation of the quantum state of atoms, molecules and solids, and molecular dynamics which also known as computer simulation method. It can be done by using structural feature based quantum chemical reactivity descriptor. The identification of ionic liquids and its Log[EC50] data are from literature data that available in Ismail Hossain thesis entitled “Synthesis, Characterization and Quantitative Structure Toxicity Relationship of Imidazolium, Pyridinium and Ammonium Based Ionic Liquids”. Each cation and anion of the ionic liquids were optimized and calculated. The geometry optimization and calculation from the software, produce the value of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). From the value of HOMO and LUMO, the value for other toxicity descriptors were obtained according to their formulas. The toxicity descriptor that involves are electrophilicity index, HOMO, LUMO, energy gap, chemical potential, hardness and electronegativity. The interrelation between the descriptors are being determined by using a multiple linear regression (MLR). From this MLR, all descriptors being analyzed and the descriptors that are significant were chosen. In order to develop the finest model equation for toxicity prediction of ionic liquids, the selected descriptors that are significant were used. The validation of model equation was performed with the Log[EC50] data from the literature and the final model equation was developed. A bigger range of ionic liquids which nearly 108 of ionic liquids can be predicted from this model equation.

Investigating salt and naphthenic acids interactions in the toxicity of oil sands process water to freshwater invertebrates

International Nuclear Information System (INIS)

Turcotte, D.; Kautzman, M.; Wojnarowicz, P.; Cutter, J.; Bird, E.; Liber, K.

2010-01-01

The hot water extraction process used to produce bitumens from oil sands produces a large volume of oil sands process water (OSPW) that contain elevated concentrations of naphthenic acids (NA) and salts. Many oil sands reclamation projects are proposing the use of OSPW as part of reconstructed wetlands projects. This study investigated the toxicity of OSPW to freshwater invertebrates. The toxic interactions between NA and salinity on freshwater invertebrates were assessed. Bioassays with laboratory-cultured Ceriodaphnia dubia were conducted to determine the toxicity of OSPW from selected water bodies. The study showed that while the concentrations of NAs and salinity were elevated in OSPW waters that caused toxic responses, the concentrations of salinity ions varied greatly among the OSPW samples. Results of the study suggested that ion composition may be a factor in toxicity. Interactions between NAs and salinity were then assessed by performing bioassays with mixtures representing major ion combinations in OSPW.

Role of pH on the acute toxicity of sulfite in water. [Carassius auratus; Leistes reticulatus

Energy Technology Data Exchange (ETDEWEB)

Sano, H.

1976-01-01

The toxicity of sulfite to fish decreases with increasing pH value, because the HSO/sub 3//sup -/ ion is more toxic than the SO/sub 3//sup 2 -/ ion. An effective sulfite concentration S/sub eff/ which is proportional to the toxicity on fish is expressed by the following equation: S/sub eff/ = (HSO/sub 3//sup -/) + f(SO/sub 3//sup 2 -/), where f is a coefficient which expresses the change of toxicity of sulfite depending on the pH of the water, and varies for each species of fish. For goldfish, owing to the very small toxic contribution of SO/sub 3//sup 2 -/ ion (f = 0.07), the pH dependence of the toxicity of sulfite on pH was so strong that sulfite seemed almost non-toxic in basic solution. However, f for guppy is somewhat larger (f = 0.20) so that the toxicity of sulfite weakly depends on the pH value of water.

Comparison of the capacity of two biotic ligand models to predict chronic copper toxicity to two Daphnia magna clones and formulation of a generalized bioavailability model.

Science.gov (United States)

Van Regenmortel, Tina; Janssen, Colin R; De Schamphelaere, Karel A C

2015-07-01

Although it is increasingly recognized that biotic ligand models (BLMs) are valuable in the risk assessment of metals in aquatic systems, the use of 2 differently structured and parameterized BLMs (1 in the United States and another in the European Union) to obtain bioavailability-based chronic water quality criteria for copper is worthy of further investigation. In the present study, the authors evaluated the predictive capacity of these 2 BLMs for a large dataset of chronic copper toxicity data with 2 Daphnia magna clones, termed K6 and ARO. One BLM performed best with clone K6 data, whereas the other performed best with clone ARO data. In addition, there was an important difference between the 2 BLMs in how they predicted the bioavailability of copper as a function of pH. These modeling results suggested that the effect of pH on chronic copper toxicity is different between the 2 clones considered, which was confirmed with additional chronic toxicity experiments. Finally, because fundamental differences in model structure between the 2 BLMs made it impossible to create an average BLM, a generalized bioavailability model (gBAM) was developed. Of the 3 gBAMs developed, the authors recommend the use of model gBAM-C(uni), which combines a log-linear relation between the 21-d median effective concentration (expressed as free Cu(2+) ion activity) and pH, with more conventional BLM-type competition constants for sodium, calcium, and magnesium. This model can be considered a first step in further improving the accuracy of chronic toxicity predictions of copper as a function of water chemistry (for a variety of Daphnia magna clones), even beyond the robustness of the current BLMs used in regulatory applications. © 2015 SETAC.

An evaluation of the whole effluent toxicity test method

International Nuclear Information System (INIS)

Osteen, D.V.

1999-01-01

Whole effluent toxicity (WET) testing has become increasingly more important to the Environmental Protection Agency (EPA) and the States in the permitting of wastewater discharges from industry and municipalities. The primary purpose of the WET test is to protect aquatic life by predicting the effect of an effluent on the receiving stream. However, there are both scientific and regulatory concerns that using WET tests to regulate industrial effluents may result in either false positives and/or false negatives. In order to realistically predict the effect of an effluent on the receiving stream, the test should be as representative as possible of the conditions in the receiving stream. Studies (Rand and Petrocelli 1985) suggested several criteria for an ideal aquatic toxicity test organism, one of which is that the organism be indigenous to, or representative of, the ecosystem receiving the effluent. The other component needed in the development of a predictive test is the use of the receiving stream water or similar synthetic water as the control and dilution water in the test method. Use of an indigenous species and receiving water in the test should help reduce the variability in the method and allow the test to predict the effect of the effluent on the receiving stream. The experience with toxicity testing at the Savannah River Site (SRS) has yielded inconclusive data because of the inconsistency and unreliability of the results. The SRS contention is that the WET method in its present form does not adequately mimic actual biological/chemical conditions of the receiving streams and is neither reasonable nor accurate. This paper discusses the rationale for such a position by SRS on toxicity testing in terms of historical permitting requirements, outfall effluent test results, standard test method evaluation, scientific review of alternate test species, and concerns over the test method expressed by other organizations. This paper presents the Savannah River Site

Complex versus simple models: ion-channel cardiac toxicity prediction.

Science.gov (United States)

Mistry, Hitesh B

2018-01-01

There is growing interest in applying detailed mathematical models of the heart for ion-channel related cardiac toxicity prediction. However, a debate as to whether such complex models are required exists. Here an assessment in the predictive performance between two established large-scale biophysical cardiac models and a simple linear model B net was conducted. Three ion-channel data-sets were extracted from literature. Each compound was designated a cardiac risk category using two different classification schemes based on information within CredibleMeds. The predictive performance of each model within each data-set for each classification scheme was assessed via a leave-one-out cross validation. Overall the B net model performed equally as well as the leading cardiac models in two of the data-sets and outperformed both cardiac models on the latest. These results highlight the importance of benchmarking complex versus simple models but also encourage the development of simple models.

Complex versus simple models: ion-channel cardiac toxicity prediction

Directory of Open Access Journals (Sweden)

Hitesh B. Mistry

2018-02-01

Full Text Available There is growing interest in applying detailed mathematical models of the heart for ion-channel related cardiac toxicity prediction. However, a debate as to whether such complex models are required exists. Here an assessment in the predictive performance between two established large-scale biophysical cardiac models and a simple linear model Bnet was conducted. Three ion-channel data-sets were extracted from literature. Each compound was designated a cardiac risk category using two different classification schemes based on information within CredibleMeds. The predictive performance of each model within each data-set for each classification scheme was assessed via a leave-one-out cross validation. Overall the Bnet model performed equally as well as the leading cardiac models in two of the data-sets and outperformed both cardiac models on the latest. These results highlight the importance of benchmarking complex versus simple models but also encourage the development of simple models.

Predicting molybdenum toxicity to higher plants: Estimation of toxicity threshold values

Energy Technology Data Exchange (ETDEWEB)

McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C.; Zhao, F.J.; Stroud, J.L. [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Zhang, H.; Fozard, S. [Division of Environmental Science, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

2010-10-15

Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED{sub 50}) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered. - Mo toxicity thresholds varied widely in different soils and therefore soil properties need to be taken into account in order to assess the risk of Mo exposure.

Building predictive in vitro pulmonary toxicity assays using high-throughput imaging and artificial intelligence.

Science.gov (United States)

Lee, Jia-Ying Joey; Miller, James Alastair; Basu, Sreetama; Kee, Ting-Zhen Vanessa; Loo, Lit-Hsin

2018-06-01

Human lungs are susceptible to the toxicity induced by soluble xenobiotics. However, the direct cellular effects of many pulmonotoxic chemicals are not always clear, and thus, a general in vitro assay for testing pulmonotoxicity applicable to a wide variety of chemicals is not currently available. Here, we report a study that uses high-throughput imaging and artificial intelligence to build an in vitro pulmonotoxicity assay by automatically comparing and selecting human lung-cell lines and their associated quantitative phenotypic features most predictive of in vivo pulmonotoxicity. This approach is called "High-throughput In vitro Phenotypic Profiling for Toxicity Prediction" (HIPPTox). We found that the resulting assay based on two phenotypic features of a human bronchial epithelial cell line, BEAS-2B, can accurately classify 33 reference chemicals with human pulmonotoxicity information (88.8% balance accuracy, 84.6% sensitivity, and 93.0% specificity). In comparison, the predictivity of a standard cell-viability assay on the same set of chemicals is much lower (77.1% balanced accuracy, 84.6% sensitivity, and 69.5% specificity). We also used the assay to evaluate 17 additional test chemicals with unknown/unclear human pulmonotoxicity, and experimentally confirmed that many of the pulmonotoxic reference and predicted-positive test chemicals induce DNA strand breaks and/or activation of the DNA-damage response (DDR) pathway. Therefore, HIPPTox helps us to uncover these common modes-of-action of pulmonotoxic chemicals. HIPPTox may also be applied to other cell types or models, and accelerate the development of predictive in vitro assays for other cell-type- or organ-specific toxicities.

Changing patterns in water toxicity associated with current use pesticides in three California agriculture regions.

Science.gov (United States)

Anderson, Brian S; Phillips, Bryn M; Voorhees, Jennifer P; Deng, Xin; Geraci, Jeff; Worcester, Karen; Tjeerdema, Ron S

2018-03-01

Regulation of agriculture irrigation water discharges in California, USA, is assessed and controlled by its 9 Regional Water Quality Control Boards under the jurisdiction of the California State Water Resources Control Board. Each Regional Water Board has developed programs to control pesticides in runoff as part of the waste discharge requirements implemented through each region's Irrigated Lands Regulatory Program. The present study assessed how pesticide use patterns differ in the Imperial (Imperial County) and the Salinas and Santa Maria (Monterey County) valleys, which host 3 of California's prime agriculture areas. Surface-water toxicity associated with current use pesticides was monitored at several sites in these areas in 2014 and 2015, and results were linked to changes in pesticide use patterns in these areas. Pesticide use patterns appeared to coincide with differences in the way agriculture programs were implemented by the 2 respective Regional Water Quality Control Boards, and these programs differed in the 2 Water Board Regions. Different pesticide use patterns affected the occurrence of pesticides in agriculture runoff, and this influenced toxicity test results. Greater detection frequency and higher concentrations of the organophosphate pesticide chlorpyrifos were detected in agriculture runoff in Imperial County compared to Monterey County, likely due to more rigorous monitoring requirements for growers using this pesticide in Monterey County. Monterey County agriculture runoff contained toxic concentrations of pyrethroid and neonicotinoid pesticides, which impacted amphipods (Hyalella azteca) and midge larvae (Chironomus dilutus) in toxicity tests. Study results illustrate how monitoring strategies need to evolve as regulatory actions affect change in pesticide use and demonstrate the importance of using toxicity test indicator species appropriate for the suite of contaminants in runoff in order to accurately assess environmental risk. Integr

A novel approach for rapidly and cost-effectively assessing toxicity of toxic metals in acidic water using an acidophilic iron-oxidizing biosensor.

Science.gov (United States)

Yang, Shih-Hung; Cheng, Kuo-Chih; Liao, Vivian Hsiu-Chuan

2017-11-01

Contamination by heavy metals and metalloids is a serious environmental and health concern. Acidic wastewaters are often associated with toxic metals which may enter and spread into agricultural soils. Several biological assays have been developed to detect toxic metals; however, most of them can only detect toxic metals in a neutral pH, not in an acidic environment. In this study, an acidophilic iron-oxidizing bacterium (IOB) Strain Y10 was isolated, characterized, and used to detect toxic metals toxicity in acidic water at pH 2.5. The colorimetric acidophilic IOB biosensor was based on the inhibition of the iron oxidizing ability of Strain Y10, an acidophilic iron-oxidizing bacterium, by metals toxicity. Our results showed that Strain Y10 is acidophilic iron-oxidizing bacterium. Thiobacillus caldus medium (TCM) (pH 2.5) supplied with both S 4 O 6 2- and glucose was the optimum growth medium for Strain Y10. The optimum temperature and pH for the growth of Strain Y10 was 45 °C and pH 2.5, respectively. Our study demonstrates that the color-based acidophilic IOB biosensor can be semi-quantitatively observed by eye or quantitatively measured by spectrometer to detect toxicity from multiple toxic metals at pH 2.5 within 45 min. Our study shows that monitoring toxic metals in acidic water is possible by using the acidophilic IOB biosensor. Our study thus provides a novel approach for rapid and cost-effective detection of toxic metals in acidic conditions that can otherwise compromise current methods of chemical analysis. This method also allows for increased efficiency when screening large numbers of environmental samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method and apparatus for the treatment of radioactive or toxic waste waters

Energy Technology Data Exchange (ETDEWEB)

Hofstaetter, K; Glock, J; Jakusch, H

1976-05-26

A method is described which proposes to store radioactive or toxic waste water in a binder, e.g. bitumen, for disposal. First of all, the liquid contained in the waste water is evaporated so that the radioactive or toxic part remains in solid form. This solid, whose specific gravity must be higher than that of the binder, is put on the surface of the binder, e.g. bitumen. Due to gravity it is embedded by sedimentation and completely covered by the binder. An apparatus with two variants to carry out the process is described, with particular emphasis on the advantages as compared to conventional methods.

Associations between water physicochemistry and Prymnesium parvum presence, abundance, and toxicity in west Texas reservoirs

Science.gov (United States)

VanLandeghem, Matthew M.; Farooqi, Mukhtar; Southard, Greg M.; Patino, Reynaldo

2015-01-01

Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity-related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga.

Characterizing toxicity of metal-contaminated sediments from mining areas

Science.gov (United States)

Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.

2015-01-01

of acid-volatile sulfide (AVS), termed simultaneously-extracted metals (SEM), are widely used to estimate the ‘potentially-bioavailable’ fraction of metals that is not bound to sulfides (i.e., SEM-AVS). Metal concentrations in pore water are widely considered to be direct measures of metal bioavailability, and predictions of toxicity based on pore-water metal concentrations may be further improved by modeling interactions of metals with other pore-water constituents using Biotic Ligand Models. Data from sediment toxicity tests and metal analyses has provided the basis for development of sediment quality guidelines, which estimate thresholds for toxicity of metals in sediments. Empirical guidelines such as Probable Effects Concentrations or (PECs) are based on associations between sediment metal concentrations and occurrence of toxic effects in large datasets. PECs do not model bioavailable metals, but they can be used to estimate the toxicity of metal mixtures using by calculation of probable effect quotients (PEQ = sediment metal concentration/PEC). In contrast, mechanistic guidelines, such as Equilibrium Partitioning Sediment Benchmarks (ESBs) attempt to predict both bioavailability and mixture toxicity. Application of these simple bioavailability models requires more extensive chemical characterization of sediments or pore water, compared to empirical guidelines, but may provide more reliable estimates of metal toxicity across a wide range of sediment types.

Management of toxic cyanobacteria for drinking water production of Ain Zada Dam.

Science.gov (United States)

Saoudi, Amel; Brient, Luc; Boucetta, Sabrine; Ouzrout, Rachid; Bormans, Myriam; Bensouilah, Mourad

2017-07-01

Blooms of toxic cyanobacteria in Algerian reservoirs represent a potential health problem, mainly from drinking water that supplies the local population of Ain Zada (Bordj Bou Arreridj). The objective of this study is to monitor, detect, and identify the existence of cyanobacteria and microcystins during blooming times. Samples were taken in 2013 from eight stations. The results show that three potentially toxic cyanobacterial genera with the species Planktothrix agardhii were dominant. Cyanobacterial biomass, phycocyanin (PC) concentrations, and microcystin (MC) concentrations were high in the surface layer and at 14 m depth; these values were also high in the treated water. On 11 May 2013, MC concentrations were 6.3 μg/L in MC-LR equivalent in the drinking water. This study shows for the first time the presence of cyanotoxins in raw and treated waters, highlighting that regular monitoring of cyanobacteria and cyanotoxins must be undertaken to avoid potential health problems.

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Mayer, D.W.; Argo, R.S.

1982-02-01

A hydrodynamic model, CAFE-I, a wave refraction model, LO3D, and a sediment and contaminant transport model, FETRA, were selected as tools for evaluating exposure levels of radionuclides, heavy metals, and other toxic chemicals in coastal waters. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interactions (e.g., adsorption and desorption), and the mechanisms governing the transport, deposition, and resuspension of contaminated sediments

Toxicity and chemical analyses of airport runoff waters in Poland.

Science.gov (United States)

Sulej, Anna Maria; Polkowska, Zaneta; Wolska, Lidia; Cieszynska, Monika; Namieśnik, Jacek

2014-05-01

The aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals--as well as TOC and conductivity--in runoff water samples collected from 2009 to 2011 at several locations on two Polish international airports. Two microbiotests (Vibrio fischeri bacteria and the crustacean Thamnocephalus platyurus) have been used to determine the ecotoxicity of airport runoff waters. The levels of many compounds exceeded several or even several tens of times the maximum permissible levels. Analysis of the obtained data shows that samples that displayed maximum toxicity towards the bioindicators Vibrio fischeri were not toxic towards Thamnocephalus platyurus. Levels of toxicity towards T. platyurus are strongly correlated with pollutants that originate from the technological operations related to the maintenance of airport infrastructure. The integrated (chemical-ecotoxicological) approach to environmental contamination assessment in and around airports yields extensive information on the quality of the environment. These methodologies can be then used as tools for tracking the environmental fate of these compounds and for assessing the environmental effect of airports. Subsequently, these data will provide a basis for airport infrastructure management.

Toxicity ratios: Their use and abuse in predicting the risk from induced cancer

International Nuclear Information System (INIS)

Mays, C.W.; Taylor, G.N.; Lloyd, R.D.

1986-01-01

The toxicity ratio concept assumes the validity of certain relationships. In some examples for bone sarcoma induction, the approximate toxicity of 239 Pu in man can be calculated algebraically from the observed toxicity in the radium-dial painters and the ratio of 239 Pu/ 226 Ra toxicities in suitable laboratory mammals. In a species highly susceptible to bone sarcoma induction, the risk coefficients for both 239 Pu and 226 Ra are elevated, but the toxicity ratio of 239 Pu to 226 Ra tends to be similar to the ratio in resistant species. Among the tested species the toxicity ratio of 239 Pu to 226 Ra ranged from 6 to 22 (a fourfold range), whereas their relative sensitivities to 239 Pu varied by a factor of 150. The toxicity ratio approach can also be used to estimate the actinide risk to man from liver cancer, by comparing to the Thorotrast patients; from lung cancer, by comparing to the uranium miners and the atomic-bomb survivors; and from neutron-induced cancers, by comparing to cancers induced by gamma rays. The toxicity ratio can be used to predict the risk to man from a specific type of cancer that has been reliably induced by a reference radiation in humans and that can be induced by both the reference and the investigated radiation in suitable laboratory animals. 26 refs., 3 figs., 1 tab

ToxiM: A Toxicity Prediction Tool for Small Molecules Developed Using Machine Learning and Chemoinformatics Approaches

Directory of Open Access Journals (Sweden)

Ashok K. Sharma

2017-11-01

Full Text Available The experimental methods for the prediction of molecular toxicity are tedious and time-consuming tasks. Thus, the computational approaches could be used to develop alternative methods for toxicity prediction. We have developed a tool for the prediction of molecular toxicity along with the aqueous solubility and permeability of any molecule/metabolite. Using a comprehensive and curated set of toxin molecules as a training set, the different chemical and structural based features such as descriptors and fingerprints were exploited for feature selection, optimization and development of machine learning based classification and regression models. The compositional differences in the distribution of atoms were apparent between toxins and non-toxins, and hence, the molecular features were used for the classification and regression. On 10-fold cross-validation, the descriptor-based, fingerprint-based and hybrid-based classification models showed similar accuracy (93% and Matthews's correlation coefficient (0.84. The performances of all the three models were comparable (Matthews's correlation coefficient = 0.84–0.87 on the blind dataset. In addition, the regression-based models using descriptors as input features were also compared and evaluated on the blind dataset. Random forest based regression model for the prediction of solubility performed better (R2 = 0.84 than the multi-linear regression (MLR and partial least square regression (PLSR models, whereas, the partial least squares based regression model for the prediction of permeability (caco-2 performed better (R2 = 0.68 in comparison to the random forest and MLR based regression models. The performance of final classification and regression models was evaluated using the two validation datasets including the known toxins and commonly used constituents of health products, which attests to its accuracy. The ToxiM web server would be a highly useful and reliable tool for the prediction of toxicity

Development and Validation of an On-Line Water Toxicity Sensor with Immobilized Luminescent Bacteria for On-Line Surface Water Monitoring.

NARCIS (Netherlands)

Woutersen, Marjolijn; van der Gaag, Bram; Abrafi Boakye, Afua; Mink, Jan; Marks, Robert S; Wagenvoort, Arco J; Ketelaars, Henk A M; Brouwer, Bram; Heringa, Minne B

2017-01-01

Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for exampleDaphnia magnaorDreissenamussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these

Testing the toxicity of metals, phenol, effluents, and receiving waters by root elongation in Lactuca sativa L.

Science.gov (United States)

Lyu, Jie; Park, Jihae; Kumar Pandey, Lalit; Choi, Soyeon; Lee, Hojun; De Saeger, Jonas; Depuydt, Stephen; Han, Taejun

2018-03-01

Phytotoxicity tests using higher plants are among the most simple, sensitive, and cost-effective of the methods available for ecotoxicity testing. In the present study, a hydroponic-based phytotoxicity test using seeds of Lactuca sativa was used to evaluate the water quality of receiving waters and effluents near two industrial sites (Soyo and Daejon) in Korea with respect to the toxicity of 10 metals (As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, Zn) and phenol, and of the receiving waters and effluents themselves. First, the L. sativa hydroponic bioassay was used to determine whether the receiving water or effluents were toxic; then, the responsible toxicant was identified. The results obtained with the L. sativa bioassay ranked the EC 50 toxicities of the investigated metal ions and phenol as: Cd > Ni > Cu > Zn > Hg > phenol > As > Mn > Cr > Pb > Fe. We found that Zn was the toxicant principally responsible for toxicity in Daejeon effluents. The Daejeon field effluent had a higher Zn concentration than permitted by the effluent discharge criteria of the Ministry of Environment of Korea. Our conclusion on the importance of Zn toxicity was supported by the results of the L. sativa hydroponic assay, which showed that the concentration of Zn required to inhibit root elongation in L. sativa by 50% (EC 50 ) was higher in the Daejeon field effluent than that of pure Zn. More importantly, we proved that the L. sativa hydroponic test method can be applied not only as an alternative tool for determining whether a given waste is acceptable for discharge into public water bodies, but also as an alternative method for measuring the safety of aquatic environments using EC 20 values, with respect to the water pollutants investigated (i.e., Cd, Cr, Cu, Pb, Mn, Hg, Ni, Zn, and phenol). Copyright © 2017. Published by Elsevier Inc.

Toxicity evaluation and prediction of toxic chemicals on activated sludge system.

Science.gov (United States)

Cai, Bijing; Xie, Li; Yang, Dianhai; Arcangeli, Jean-Pierre

2010-05-15

The gaps of data for evaluating toxicity of new or overloaded organic chemicals on activated sludge system resulted in the requirements for methodology of toxicity estimation. In this study, 24 aromatic chemicals typically existed in the industrial wastewater were selected and classified into three groups of benzenes, phenols and anilines. Their toxicity on activated sludge was then investigated. Two indexes of IC(50-M) and IC(50-S) were determined respectively from the respiration rates of activated sludge with different toxicant concentration at mid-term (24h) and short-term (30min) time intervals. Experimental results showed that the group of benzenes was the most toxic, followed by the groups of phenols and anilines. The values of IC(50-M) of the tested chemicals were higher than those of IC(50-S). In addition, quantitative structure-activity relationships (QSARs) models developed from IC(50-M) were more stable and accurate than those of IC(50-S). The multiple linear models based on molecular descriptors and K(ow) presented better reliability than single linear models based on K(ow). Among these molecular descriptors, E(lumo) was the most important impact factor for evaluation of mid-term toxicity. Copyright (c) 2009 Elsevier B.V. All rights reserved.

A portable cell-based impedance sensor for toxicity testing of drinking water.

Science.gov (United States)

Curtis, Theresa M; Widder, Mark W; Brennan, Linda M; Schwager, Steven J; van der Schalie, William H; Fey, Julien; Salazar, Noe

2009-08-07

A major limitation to using mammalian cell-based biosensors for field testing of drinking water samples is the difficulty of maintaining cell viability and sterility without an on-site cell culture facility. This paper describes a portable automated bench-top mammalian cell-based toxicity sensor that incorporates enclosed fluidic biochips containing endothelial cells monitored by Electric Cell-substrate Impedance Sensing (ECIS) technology. Long-term maintenance of cells on the biochips is made possible by using a compact, self-contained disposable media delivery system. The toxicity sensor monitors changes in impedance of cell monolayers on the biochips after the introduction of water samples. The fluidic biochip includes an ECIS electronic layer and a polycarbonate channel layer, which together reduce initial impedance disturbances seen in commercially available open well ECIS chips caused by the mechanics of pipetting while maintaining the ability of the cells to respond to toxicants. A curve discrimination program was developed that compares impedance values over time between the control and treatment channels on the fluidic biochip and determines if they are significantly different. Toxicant responses of bovine pulmonary artery endothelial cells grown on fluidic biochips are similar to cells on commercially-available open well chips, and these cells can be maintained in the toxicity sensor device for at least nine days using an automated media delivery system. Longer-term cell storage is possible; bovine lung microvessel endothelial cells survive for up to four months on the fluidic biochips and remain responsive to a model toxicant. This is the first demonstration of a portable bench top system capable of both supporting cell health over extended periods of time and obtaining impedance measurements from endothelial cell monolayers after toxicant exposure.

Migration of toxicants from plastics into drinking water during storage ...

African Journals Online (AJOL)

In this study, migration of toxicants, such as, manufacturing additives and previously adsorbed materials into drinking water stored inside plastic containers was investigated. The study considered virgin containers as well as those previously used to store sulphuric acid, calcium hypochlorite, methyl ethyl ketone (MEK) and ...

Toxic effects of juvenile sablefish, Anoplopoma fimbria by ammonia exposure at different water temperature.

Science.gov (United States)

Kim, Jun-Hwan; Park, Hee-Ju; Hwang, In-Ki; Han, Jae-Min; Kim, Do-Hyung; Oh, Chul Woong; Lee, Jung-Sick; Kang, Ju-Chan

2017-09-01

Juvenile sablefish, Anoplopoma fimbria (mean length 17.1±2.4cm, and mean weight 75.6±5.7g) were used to evaluate toxic effects on antioxidant systems, immune responses, and stress indicators by ammonia exposure (0, 0.25, 0.75, and 1.25mg/L) at different water temperature (12 and 17°C) in 1 and 2 months. In antioxidant responses, superoxide dismutase (SOD) and catalase (CAT) were significantly increased by ammonia exposure, whereas glutathione (GSH) was decreased. In immune responses, lysozyme and phagocytosis activity were significantly increased by ammonia exposure. In stress indicators, plasma glucose, heat shock protein 70 (HSP 70), and cortisol were significantly increased. At high water temperature (17°C), alterations by ammonia exposure were more distinctly. The results of this study indicated that ammonia exposure can induce toxic effects in the sablefish, and high water temperature can affect the ammonia exposure toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

On the use of mixture toxicity assessment in REACH and the water framework directive

DEFF Research Database (Denmark)

Syberg, Kristian; Jensen, T.S.; Cedergreen, Nina

2009-01-01

  This review seeks to connect the scientific theory of mixture toxicity to its implementation within different regulatory frameworks. The aim is to demonstrate how mixture toxicity assessment can be more thoroughly integrated into the European chemical regulations, REACH and the Water Framework...... of how the methods could be applied within REACH and WFD. It is concluded that oncentration addition should be applied as a default model for mixture toxicity assessment. Furthermore, it is concluded that REACH and WFD only include mixture toxicity assessments in specific situations. However, it is shown...

Use of passive samplers for improving oil toxicity and spill effects assessment

International Nuclear Information System (INIS)

Letinski, Daniel; Parkerton, Thomas; Redman, Aaron; Manning, Ryan; Bragin, Gail; Febbo, Eric; Palandro, David; Nedwed, Tim

2014-01-01

Highlights: • Methods to quantify dissolved hydrocarbons needed to link oil exposures to toxicity. • Solid phase microextraction (SPME) fibers used to measure dissolved hydrocarbons. • SPME results reliably predicted acute toxicity for range of dispersed oils. • Oil droplets and chemical dispersant did not significantly contribute to toxicity. • SPME analysis improves oil exposure assessment in lab and field studies. - Abstract: Methods that quantify dissolved hydrocarbons are needed to link oil exposures to toxicity. Solid phase microextraction (SPME) fibers can serve this purpose. If fibers are equilibrated with oiled water, dissolved hydrocarbons partition to and are concentrated on the fiber. The absorbed concentration (C polymer ) can be quantified by thermal desorption using GC/FID. Further, given that the site of toxic action is hypothesized as biota lipid and partitioning of hydrocarbons to lipid and fibers is well correlated, C polymer is hypothesized to be a surrogate for toxicity prediction. To test this method, toxicity data for physically and chemically dispersed oils were generated for shrimp, Americamysis bahia, and compared to test exposures characterized by C polymer . Results indicated that C polymer reliably predicted toxicity across oils and dispersions. To illustrate field application, SPME results are reported for oil spills at the Ohmsett facility. SPME fibers provide a practical tool to improve characterization of oil exposures and predict effects in future lab and field studies

Using machine learning and quantum chemistry descriptors to predict the toxicity of ionic liquids.

Science.gov (United States)

Cao, Lingdi; Zhu, Peng; Zhao, Yongsheng; Zhao, Jihong

2018-06-15

Large-scale application of ionic liquids (ILs) hinges on the advancement of designable and eco-friendly nature. Research of the potential toxicity of ILs towards different organisms and trophic levels is insufficient. Quantitative structure-activity relationships (QSAR) model is applied to evaluate the toxicity of ILs towards the leukemia rat cell line (ICP-81). The structures of 57 cations and 21 anions were optimized by quantum chemistry. The electrostatic potential surface area (S EP ) and charge distribution area (S σ-profile ) descriptors are calculated and used to predict the toxicity of ILs. The performance and predictive aptitude of extreme learning machine (ELM) model are analyzed and compared with those of multiple linear regression (MLR) and support vector machine (SVM) models. The highest R 2 and the lowest AARD% and RMSE of the training set, test set and total set for the ELM are observed, which validates the superior performance of the ELM than that of obtained by the MLR and SVM. The applicability domain of the model is assessed by the Williams plot. Copyright © 2018 Elsevier B.V. All rights reserved.

Simulation of heavy metal contamination of fresh water bodies: toxic ...

African Journals Online (AJOL)

Michael Horsfall

www.bioline.org.br/ja. Simulation of heavy metal contamination of fresh water bodies: toxic effects in the ... 96 hours (though sampling was done at the 48th hour). Biochemical markers of ... silver, while enhancing the bioavailability of mercury in Ceriodaphnia ..... Biochemical and molecular disorders of bilirubin metabolism.

In Silico Prediction of Chemical Toxicity for Drug Design Using Machine Learning Methods and Structural Alerts

Science.gov (United States)

Yang, Hongbin; Sun, Lixia; Li, Weihua; Liu, Guixia; Tang, Yun

2018-02-01

For a drug, safety is always the most important issue, including a variety of toxicities and adverse drug effects, which should be evaluated in preclinical and clinical trial phases. This review article at first simply introduced the computational methods used in prediction of chemical toxicity for drug design, including machine learning methods and structural alerts. Machine learning methods have been widely applied in qualitative classification and quantitative regression studies, while structural alerts can be regarded as a complementary tool for lead optimization. The emphasis of this article was put on the recent progress of predictive models built for various toxicities. Available databases and web servers were also provided. Though the methods and models are very helpful for drug design, there are still some challenges and limitations to be improved for drug safety assessment in the future.

In Silico Prediction of Chemical Toxicity for Drug Design Using Machine Learning Methods and Structural Alerts

Directory of Open Access Journals (Sweden)

Hongbin Yang

2018-02-01

Full Text Available During drug development, safety is always the most important issue, including a variety of toxicities and adverse drug effects, which should be evaluated in preclinical and clinical trial phases. This review article at first simply introduced the computational methods used in prediction of chemical toxicity for drug design, including machine learning methods and structural alerts. Machine learning methods have been widely applied in qualitative classification and quantitative regression studies, while structural alerts can be regarded as a complementary tool for lead optimization. The emphasis of this article was put on the recent progress of predictive models built for various toxicities. Available databases and web servers were also provided. Though the methods and models are very helpful for drug design, there are still some challenges and limitations to be improved for drug safety assessment in the future.

In Silico Prediction of Chemical Toxicity for Drug Design Using Machine Learning Methods and Structural Alerts.

Science.gov (United States)

Yang, Hongbin; Sun, Lixia; Li, Weihua; Liu, Guixia; Tang, Yun

2018-01-01

During drug development, safety is always the most important issue, including a variety of toxicities and adverse drug effects, which should be evaluated in preclinical and clinical trial phases. This review article at first simply introduced the computational methods used in prediction of chemical toxicity for drug design, including machine learning methods and structural alerts. Machine learning methods have been widely applied in qualitative classification and quantitative regression studies, while structural alerts can be regarded as a complementary tool for lead optimization. The emphasis of this article was put on the recent progress of predictive models built for various toxicities. Available databases and web servers were also provided. Though the methods and models are very helpful for drug design, there are still some challenges and limitations to be improved for drug safety assessment in the future.

Plasma citrulline levels predict intestinal toxicity in patients treated with pelvic radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Onal, Cem; Kotek, Ayse; Arslan, Gungor; Topkan, Erkan (Dept. of Radiation Oncology, Baskent Univ. Faculty of Medicine, Adana (Turkey)), E-mail: hcemonal@hotmail.com; Unal, Birsel (Dept. of Biochemistry, Baskent Univ. Faculty of Medicine, Ankara (Turkey)); Yavuz, Aydin; Yavuz, Melek (Dept. of Radiation Oncology, Akdeniz Univ. Faculty of Medicine, Antalya (Turkey))

2011-11-15

Background. Radiotherapy (RT) for abdominal and pelvic malignancies often causes severe small bowel toxicity. Citrulline concentrations are known to decrease with intestinal failure. We thus evaluated the feasibility of plasma citrulline levels in predicting radiation-induced intestinal toxicity. Material and methods. Fifty-three patients (36 prostate cancer, 17 endometrial cancer) who received 45 Gy pelvic RT using conventional fractionation were prospectively evaluated. Patients with prostate cancer received an additional 25-30.6 Gy conformal boost. Plasma citrulline levels were assessed on day 0, mid- (week 3) and post-RT (week 8), and four months post-RT. Dose-volume histogram, citrulline concentration changes, and weekly intestinal toxicity scores were analyzed. Results. Mean age was 63 years (range: 43-81 years) and mean baseline citrulline concentration was 38.0 +- 10.1 mumol/l. Citrulline concentrations were significantly reduced at week 3 (27.4 +- 5.9 mumol/l; p < 0.0001), treatment end (29.9 +- 8.8 mumol/l; p < 0.0001), and four months post-treatment (34.3 +- 12.1; p 0.01). The following factor pairs were significantly positively correlated: Citrulline concentration/mean bowel dose during, end of treatment, and four months post-RT; dose-volume parameters/citrulline change groups; cumulative mean radiation dose/intestinal toxicity at end and four months post-RT; citrulline changes/intestinal toxicity during and end of RT. Citrulline concentration changes significantly differed during treatment according to RTOG intestinal toxicity grades (p < 0.0001). Although the citrulline changes differed significantly within RTOG intestinal toxicity grades (p = 0.003), the difference between Grade 0 and Grade 1 did not differ significantly at the end of the treatment. At four months after RT, no significant differences were apparent. Conclusion. Citrulline-based assessment scores are objective and should be considered in measuring radiation-induced intestinal toxicity

Plasma citrulline levels predict intestinal toxicity in patients treated with pelvic radiotherapy

International Nuclear Information System (INIS)

Onal, Cem; Kotek, Ayse; Arslan, Gungor; Topkan, Erkan; Unal, Birsel; Yavuz, Aydin; Yavuz, Melek

2011-01-01

Background. Radiotherapy (RT) for abdominal and pelvic malignancies often causes severe small bowel toxicity. Citrulline concentrations are known to decrease with intestinal failure. We thus evaluated the feasibility of plasma citrulline levels in predicting radiation-induced intestinal toxicity. Material and methods. Fifty-three patients (36 prostate cancer, 17 endometrial cancer) who received 45 Gy pelvic RT using conventional fractionation were prospectively evaluated. Patients with prostate cancer received an additional 25-30.6 Gy conformal boost. Plasma citrulline levels were assessed on day 0, mid- (week 3) and post-RT (week 8), and four months post-RT. Dose-volume histogram, citrulline concentration changes, and weekly intestinal toxicity scores were analyzed. Results. Mean age was 63 years (range: 43-81 years) and mean baseline citrulline concentration was 38.0 ± 10.1 μmol/l. Citrulline concentrations were significantly reduced at week 3 (27.4 ± 5.9 μmol/l; p < 0.0001), treatment end (29.9 ± 8.8 μmol/l; p < 0.0001), and four months post-treatment (34.3 ± 12.1; p 0.01). The following factor pairs were significantly positively correlated: Citrulline concentration/mean bowel dose during, end of treatment, and four months post-RT; dose-volume parameters/citrulline change groups; cumulative mean radiation dose/intestinal toxicity at end and four months post-RT; citrulline changes/intestinal toxicity during and end of RT. Citrulline concentration changes significantly differed during treatment according to RTOG intestinal toxicity grades (p < 0.0001). Although the citrulline changes differed significantly within RTOG intestinal toxicity grades (p = 0.003), the difference between Grade 0 and Grade 1 did not differ significantly at the end of the treatment. At four months after RT, no significant differences were apparent. Conclusion. Citrulline-based assessment scores are objective and should be considered in measuring radiation-induced intestinal toxicity

EVALUATING THE ROLE OF ION COMPOSITION ON THE TOXICITY OF COPPER TO CERIODAPHNIA DUBIA IN VERY HARD WATERS

Science.gov (United States)

The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States. - - - Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g. alkalinity ...

Work-principle model for predicting toxic fumes of nonideal explosives

Energy Technology Data Exchange (ETDEWEB)

Wieland, Michael S. [National Institute of Occupational Safety and Health, Pittsburgh Research Center, P.O. Box 18070, Pittsburgh, PA 15236-0070 (United States)

2004-08-01

The work-principle from thermodynamics was used to formulate a model for predicting toxic fumes from mining explosives in underground chamber tests, where rapid turbulent combustion within the surrounding air noticeably changes the resulting concentrations. Two model constants were required to help characterize the reaction zone undergoing rapid chemical transformations in conjunction with heat transfer and work output: a stoichiometry mixing fraction and a reaction-quenching temperature. Rudimentary theory with an unsteady uniform concentration gradient was taken to characterize the combustion zone, yielding 75% for the mixing fraction. Four quenching temperature trends were resolved and compared to test results of ammonium nitrate compositions with different fuel-oil percentages (ANFO). The quenching temperature 2345 K was the optimum choice for fitting the two major components of fume toxicity: carbon monoxide (CO) and total nitrogen oxides (NO{sub X}). The resulting two-constant model was used to generate comparisons for test results of ANFO compositions with additives. Though respectable fits were usually found, charge formulations which reacted weakly could not be resolved numerically. The work-principle model yields toxic concentrations for a range of charge formulations, making it a useful tool for investigating the potential hazard of released fumes and reducing the risk of unwanted incidents. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Comparative toxicity test of water-accommodated fractions of oils and oil dispersants to marine organisms

International Nuclear Information System (INIS)

1989-01-01

This reference method describes a simple procedure for comparing the toxicity of oil, oil dispersants, and mixtures thereof, to marine animals. It allows the toxicity of different dispersants to be rapidly compared to that of oil, or of a mixture of oil an oil dispersant. It is designed for routine monitoring and screening purposes and is not appropriate as a research method. The physical and chemical properties of oil dispersants create many difficulties in the measurements of their toxicity to marine organisms. Strictly speaking, their toxicity can only be accurately estimated using complex procedures and apparatus. (A relatively simple apparatus for preparing oil/water or oil/water/oil dispersant emulsions is described in Appendix B). Simpler methods can provide useful information, provided their limitations are clearly understood and taken into consideration in the assessment and application of their results. Some of the special considerations relating to the measurement of the toxicity of oil and oil dispersants are described in Appendix A. The Appendix also explains the rationale and limitations of the method described here. 3 refs, 4 figs, 2 tabs

A text-based data mining and toxicity prediction modeling system for a clinical decision support in radiation oncology: A preliminary study

Science.gov (United States)

Kim, Kwang Hyeon; Lee, Suk; Shim, Jang Bo; Chang, Kyung Hwan; Yang, Dae Sik; Yoon, Won Sup; Park, Young Je; Kim, Chul Yong; Cao, Yuan Jie

2017-08-01

The aim of this study is an integrated research for text-based data mining and toxicity prediction modeling system for clinical decision support system based on big data in radiation oncology as a preliminary research. The structured and unstructured data were prepared by treatment plans and the unstructured data were extracted by dose-volume data image pattern recognition of prostate cancer for research articles crawling through the internet. We modeled an artificial neural network to build a predictor model system for toxicity prediction of organs at risk. We used a text-based data mining approach to build the artificial neural network model for bladder and rectum complication predictions. The pattern recognition method was used to mine the unstructured toxicity data for dose-volume at the detection accuracy of 97.9%. The confusion matrix and training model of the neural network were achieved with 50 modeled plans (n = 50) for validation. The toxicity level was analyzed and the risk factors for 25% bladder, 50% bladder, 20% rectum, and 50% rectum were calculated by the artificial neural network algorithm. As a result, 32 plans could cause complication but 18 plans were designed as non-complication among 50 modeled plans. We integrated data mining and a toxicity modeling method for toxicity prediction using prostate cancer cases. It is shown that a preprocessing analysis using text-based data mining and prediction modeling can be expanded to personalized patient treatment decision support based on big data.

Effect of water treatment residuals on soil phosphorus, copper and aluminium availability and toxicity

Energy Technology Data Exchange (ETDEWEB)

Lombi, E., E-mail: enzo.lombi@unisa.edu.a [CSIRO Land and Water, Centre for Environmental Contaminant Research, PMB 2, Glen Osmond, SA 5064 (Australia); Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, Mawson Lakes Campus, Mawson Lakes, SA 5095 (Australia); CRC CARE, PO Box 486, Salisbury, SA 5106 (Australia); Stevens, D.P. [CSIRO Land and Water, Centre for Environmental Contaminant Research, PMB 2, Glen Osmond, SA 5064 (Australia); Arris Pty Ltd, PO Box 5143, Burnley, Victoria 3121 (Australia); McLaughlin, M.J. [CSIRO Land and Water, Centre for Environmental Contaminant Research, PMB 2, Glen Osmond, SA 5064 (Australia); Soil and Land Systems, University of Adelaide, PMB 1, Glen Osmond, SA 5064 (Australia)

2010-06-15

Water treatment residuals (WTRs) are produced by the treatment of potable water with coagulating agents. Beneficial recycling in agriculture is hampered by the fact that WTRs contain potentially toxic contaminants (e.g. copper and aluminium) and they bind phosphorus strongly. These issues were investigated using a plant bioassay (Lactuca sativa), chemical extractions and an isotopic dilution technique. Two WTRs were applied to an acidic and a neutral pH soil at six rates. Reductions in plant growth in amended soils were due to WTR-induced P deficiency, rather than Al or Cu toxicity. The release of potentially toxic Al from WTRs was found to be mitigated by their alkaline nature and pH buffering capacity. However, acidification of WTRs was shown to release more soluble Al than soil naturally high in Al. Copper availability was relatively low in all treatments. However, the lability of WTR-Cu increased when the WTR was applied to the soil. - The effect of water treatment residue application to soil was investigated in relation to phosphorus availability, and copper and aluminium phytotoxicity.

Effect of water treatment residuals on soil phosphorus, copper and aluminium availability and toxicity

International Nuclear Information System (INIS)

Lombi, E.; Stevens, D.P.; McLaughlin, M.J.

2010-01-01

Water treatment residuals (WTRs) are produced by the treatment of potable water with coagulating agents. Beneficial recycling in agriculture is hampered by the fact that WTRs contain potentially toxic contaminants (e.g. copper and aluminium) and they bind phosphorus strongly. These issues were investigated using a plant bioassay (Lactuca sativa), chemical extractions and an isotopic dilution technique. Two WTRs were applied to an acidic and a neutral pH soil at six rates. Reductions in plant growth in amended soils were due to WTR-induced P deficiency, rather than Al or Cu toxicity. The release of potentially toxic Al from WTRs was found to be mitigated by their alkaline nature and pH buffering capacity. However, acidification of WTRs was shown to release more soluble Al than soil naturally high in Al. Copper availability was relatively low in all treatments. However, the lability of WTR-Cu increased when the WTR was applied to the soil. - The effect of water treatment residue application to soil was investigated in relation to phosphorus availability, and copper and aluminium phytotoxicity.

WATER DEMAND PREDICTION USING ARTIFICIAL NEURAL ...

African Journals Online (AJOL)

This paper presents Hourly water demand prediction at the demand nodes of a water distribution network using NeuNet Pro 2.3 neural network software and the monitoring and control of water distribution using supervisory control. The case study is the Laminga Water Treatment Plant and its water distribution network, Jos.

Application of enzyme multibiosensor for toxicity analysis of real water samples of different origin

Directory of Open Access Journals (Sweden)

Soldatkin A. P.

2009-06-01

Full Text Available Aim. The analysis of toxicity of different water samples with the multibiosensor developed earlier. Methods. The potentiometric multibiosensor with several immobilized enzymes as bioselective elements and the matrix of pH-sensitive field effect transistors as transducers of the biochemical signal into the electric one was applied for the analysis. Results. The bioselective elements of the multibiosensor were developed using acetylcholinesterase, butyryl- cholinesterase, urease, glucose oxidase, and three-enzyme system (invertase, mutarotase, glucose oxidase. The measurement of toxic compounds in water samples of different origin was performed using the constructed sensor. The results obtained were compared with those obtained by the conventional methods of toxic agent’s analysis (atomic absorption spectrometry, thin-film chroma- tography, and atomic absorbic analyser of mercury. Conclusion. A strong conformity between the results obtained with the multibiosensor and traditional methods has been shown.

Accurate prediction of the toxicity of benzoic acid compounds in mice via oral without using any computer codes

International Nuclear Information System (INIS)

Keshavarz, Mohammad Hossein; Gharagheizi, Farhad; Shokrolahi, Arash; Zakinejad, Sajjad

2012-01-01

Highlights: ► A novel method is introduced for desk calculation of toxicity of benzoic acid derivatives. ► There is no need to use QSAR and QSTR methods, which are based on computer codes. ► The predicted results of 58 compounds are more reliable than those predicted by QSTR method. ► The present method gives good predictions for further 324 benzoic acid compounds. - Abstract: Most of benzoic acid derivatives are toxic, which may cause serious public health and environmental problems. Two novel simple and reliable models are introduced for desk calculations of the toxicity of benzoic acid compounds in mice via oral LD 50 with more reliance on their answers as one could attach to the more complex outputs. They require only elemental composition and molecular fragments without using any computer codes. The first model is based on only the number of carbon and hydrogen atoms, which can be improved by several molecular fragments in the second model. For 57 benzoic compounds, where the computed results of quantitative structure–toxicity relationship (QSTR) were recently reported, the predicted results of two simple models of present method are more reliable than QSTR computations. The present simple method is also tested with further 324 benzoic acid compounds including complex molecular structures, which confirm good forecasting ability of the second model.

Trophic state and toxic cyanobacteria density in optimization modeling of multi-reservoir water resource systems.

Science.gov (United States)

Sulis, Andrea; Buscarinu, Paola; Soru, Oriana; Sechi, Giovanni M

2014-04-22

The definition of a synthetic index for classifying the quality of water bodies is a key aspect in integrated planning and management of water resource systems. In previous works [1,2], a water system optimization modeling approach that requires a single quality index for stored water in reservoirs has been applied to a complex multi-reservoir system. Considering the same modeling field, this paper presents an improved quality index estimated both on the basis of the overall trophic state of the water body and on the basis of the density values of the most potentially toxic Cyanobacteria. The implementation of the index into the optimization model makes it possible to reproduce the conditions limiting water use due to excessive nutrient enrichment in the water body and to the health hazard linked to toxic blooms. The analysis of an extended limnological database (1996-2012) in four reservoirs of the Flumendosa-Campidano system (Sardinia, Italy) provides useful insights into the strengths and limitations of the proposed synthetic index.

Toxicity of sediment pore water associated with offshore oil and gas platforms in the Gulf of Mexico

International Nuclear Information System (INIS)

Carr, R.S.; Chapman, D.C.

1993-01-01

As a part of a multidisciplinary program to assess the long-term impacts of offshore petroleum production in the Gulf of Mexico, a series of sediment porewater toxicity tests were conducted. Sediments were samples from five petroleum production platforms along five radial transects. Pore water was extracted from the sediment using a pressure extraction device, centrifuged, and frozen for later toxicity testing and chemical analysis. The sea urchin (Arbacia punctulata) embryological development assay and fertilization assay were used to assess porewater toxicity. Significant decreases in normal development of embryos was observed at 14 stations and fertilization was reduced at three stations. All stations with reduced fertilization also showed impaired development in the embryological development assay. All but three toxic sites were within 150 m of the platform. The six most toxic stations were at one platform near the Flower Garden reef, occurring near the platform along three radii; toxicity was always greater at the first site on a radium than at the second. Toxicity is discussed in relation to metal and hydrocarbon concentrations in whole sediment and in pore water

Nickel toxicity to cardinal tetra (Paracheirodon axelrodi) differs seasonally and among the black, white and clear river waters of the Amazon basin.

Science.gov (United States)

Holland, Aleicia; Wood, Chris M; Smith, D Scott; Correia, Tiago Gabriel; Val, Adalberto L

2017-10-15

This study investigated the acute toxicity of nickel (Ni) to cardinal tetra (Paracheirodon axelrodi), within the three main water types of the Amazon basin: black (Rio Negro), white (Rio Solimões) and clear (Rio Tapajós) during the wet and dry season at pH 7 (representative of white and clear rivers) and pH 4 (representative of black waters). The influence of dissolved organic carbon (DOC) quality on Ni toxicity within the three waters was also explored via the use of DOC isolates. Differences in water chemistry, DOC quality and ion concentrations were shown between waters and between seasons. Toxicity of Ni was shown to vary between river waters, seasons, and pHs. Ni was significantly less toxic during the dry season at pH 4 in all three river waters; for example, black water during the wet season had an LC 50 of 9.72 mg Ni/L compared to 41.5 mg Ni/L during the dry season. At pH 7, contrasting effects in toxicity between seasons were shown between black and clear waters (black: wet = 28.9 mg/L, dry = 17.3 mg/L; clear: wet = 13.8 mg/L, dry = 24.1 mg/L). There were no significant differences in Ni toxicity for white waters at pH 7 (white: wet = 22.2 mg/L, dry = 21.8). Overall, Ni was shown to be more toxic at pH 7 than at pH 4 except in black water during the wet season. Toxicity of Ni at pH 4 was positively related to DOC concentration and amount of humic-like and fulvic-like DOC and negatively related to fluorescence index. Therefore, at pH 4, Ni is more toxic in waters containing more allochthonous DOC, consisting of higher amounts of humic-like and fulvic-like components. LC 50 values for the different DOC concentrates at the same DOC concentration of 4.5 mg/L (black: 26.8 mg/L; white: 73.3 mg/L; clear: 49.2) support the river water findings at pH 4 (Ni more toxic in presence of black DOC) indicating that DOC quality alone can influence Ni toxicity at this pH. Copyright © 2017 Elsevier Ltd. All rights reserved.

An integrated multi-label classifier with chemical-chemical interactions for prediction of chemical toxicity effects.

Science.gov (United States)

Liu, Tao; Chen, Lei; Pan, Xiaoyong

2018-05-31

Chemical toxicity effect is one of the major reasons for declining candidate drugs. Detecting the toxicity effects of all chemicals can accelerate the procedures of drug discovery. However, it is time-consuming and expensive to identify the toxicity effects of a given chemical through traditional experiments. Designing quick, reliable and non-animal-involved computational methods is an alternative way. In this study, a novel integrated multi-label classifier was proposed. First, based on five types of chemical-chemical interactions retrieved from STITCH, each of which is derived from one aspect of chemicals, five individual classifiers were built. Then, several integrated classifiers were built by integrating some or all individual classifiers. By testing the integrated classifiers on a dataset with chemicals and their toxicity effects in Accelrys Toxicity database and non-toxic chemicals with their performance evaluated by jackknife test, an optimal integrated classifier was selected as the proposed classifier, which provided quite high prediction accuracies and wide applications. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Behavioral, clinical, and pathological characterization of acid metalliferous water toxicity in mallards

Science.gov (United States)

Isanhart, John P.; Wu, Hongmei; Pandher, Karamjeet; MacRae, Russell K.; Cox, Stephen B.; Hooper, Michael J.

2011-01-01

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ± SE 127.9 ± 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and

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

International Nuclear Information System (INIS)

Marchich, S.

1997-01-01

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

The biomonitoring and bioremediation of toxic water resulting from municipal waste storage of Somârd, Sibiu county

OpenAIRE

Ioan C. Oprea; Dana Malschi; Liviu O. Muntean

2013-01-01

This paper presents information from the specialty literature and laboratory experimental results on biomonitoring, phytoextraction, biodegradation, and biotransformation of toxic water pollutants at the biotechnology laboratory of the Faculty of Environmental Science and Engineering. The study was conducted in laboratory micro tanks with contaminated water from the municipal landfill water storage pit with toxic bund of Somârd/Medias, Sibiu County, in order to research and develo...

Mixture toxicity of wood preservative products in the fish embryo toxicity test.

Science.gov (United States)

Coors, Anja; Dobrick, Jan; Möder, Monika; Kehrer, Anja

2012-06-01

Wood preservative products are used globally to protect wood from fungal decay and insects. We investigated the aquatic toxicity of five commercial wood preservative products, the biocidal active substances and some formulation additives contained therein, as well as six generic binary mixtures of the active substances in the fish embryo toxicity test (FET). Median lethal concentrations (LC50) of the single substances, the mixtures, and the products were estimated from concentration-response curves and corrected for concentrations measured in the test medium. The comparison of the experimentally observed mixture toxicity with the toxicity predicted by the concept of concentration addition (CA) showed less than twofold deviation for all binary mixtures of the active substances and for three of the biocidal products. A more than 60-fold underestimation of the toxicity of the fourth product by the CA prediction was detected and could be explained fully by the toxicity of one formulation additive, which had been labeled as a hazardous substance. The reason for the 4.6-fold underestimation of toxicity of the fifth product could not be explained unambiguously. Overall, the FET was found to be a suitable screening tool to verify whether the toxicity of formulated wood preservatives can reliably be predicted by CA. Applied as a quick and simple nonanimal screening test, the FET may support approaches of applying component-based mixture toxicity predictions within the environmental risk assessment of biocidal products, which is required according to European regulations. Copyright © 2012 SETAC.

Potential for photoenhanced toxicity of spilled oil in Prince William Sound and Gulf of Alaska Waters

International Nuclear Information System (INIS)

Barron, M.G.; Ka'aihue, L.

2001-01-01

Photoenhanced toxicity is the increase in the toxicity of a chemical in the presence of ultraviolet light (UV) compared to a standard laboratory test conducted with fluorescent lighting (minimal UV). Oil products, weathered oil, and specific polycyclic aromatic compounds present in oil are 2 to greater than 1000 times more toxic in the presence of UV. The photoenhanced toxicity of oil to fish and aquatic invertebrates appears to occur through a process of photosensitization, rather than photomodification of the aqueous phase oil. In photosensitization, the bioaccumulated chemical transfers light energy to other molecules causing toxicity through tissue damage rather than a narcosis mechanism. The available evidence indicates that phototoxic components of oil are specific 3-5 ring polycyclic aromatic hydrocarbons (PAHs) and heterocycles. Determinants of photoenhanced toxicity include the extent of oil bioaccumulation in aquatic organisms and the spectra and intensity of UV exposure. No studies have specifically investigated the photoenhanced toxicity of spilled oil in Alaska waters. Although there are substantial uncertainties, the results of this evaluation indicate there is potential for photoenhanced toxicity of spilled oil in Prince William Sound and the Gulf of Alaska. The potential hazard of photoenhanced toxicity may be greatest for embryo and larval stages of aquatic organisms that are relatively translucent to UV and inhabit the photic zone of the water column and intertidal areas. Photoenhanced toxicity should be considered in oil spill response because the spatial and temporal extent of injury to aquatic organisms may be underestimated if based on standard laboratory bioassays and existing toxicity databases. Additionally, the choice of counter measures and oil removal operations may influence the degree of photoenhanced toxicity. (author)

Microencapsulated Aliivibrio fischeri in Alginate Microspheres for Monitoring Heavy Metal Toxicity in Environmental Waters

Directory of Open Access Journals (Sweden)

Dedi Futra

2014-12-01

Full Text Available In this article a luminescence fiber optic biosensor for the microdetection of heavy metal toxicity in waters based on the marine bacterium Aliivibrio fischeri (A. fischeri encapsulated in alginate microspheres is described. Cu(II, Cd(II, Pb(II, Zn(II, Cr(VI, Co(II, Ni(II, Ag(I and Fe(II were selected as sample toxic heavy metal ions for evaluation of the performance of this toxicity microbiosensor. The loss of bioluminescence response from immobilized A. fischeri bacterial cells corresponds to changes in the toxicity levels. The inhibition of the luminescent biosensor response collected at excitation and emission wavelengths of 287 ± 2 nm and 487 ± 2 nm, respectively, was found to be reproducible and repeatable within the relative standard deviation (RSD range of 2.4–5.7% (n = 8. The toxicity biosensor based on alginate micropsheres exhibited a lower limit of detection (LOD for Cu(II (6.40 μg/L, Cd(II (1.56 μg/L, Pb(II (47 μg/L, Ag(I (18 μg/L than Zn(II (320 μg/L, Cr(VI (1,000 μg/L, Co(II (1700 μg/L, Ni(II (2800 μg/L, and Fe(III (3100 μg/L. Such LOD values are lower when compared with other previous reported whole cell toxicity biosensors using agar gel, agarose gel and cellulose membrane biomatrices used for the immobilization of bacterial cells. The A. fischeri bacteria microencapsulated in alginate biopolymer could maintain their metabolic activity for a prolonged period of up to six weeks without any noticeable changes in the bioluminescence response. The bioluminescent biosensor could also be used for the determination of antagonistic toxicity levels for toxicant mixtures. A comparison of the results obtained by atomic absorption spectroscopy (AAS and using the proposed luminescent A. fischeri-based biosensor suggests that the optical toxicity biosensor can be used for quantitative microdetermination of heavy metal toxicity in environmental water samples.

Early hematologic changes during prostate cancer radiotherapy predictive for late urinary and bowel toxicity

Energy Technology Data Exchange (ETDEWEB)

Pinkawa, Michael; Djukic, Victoria; Klotz, Jens; Holy, Richard; Eble, Michael J. [RWTH Aachen University, Department of Radiation Oncology, Aachen (Germany); Ribbing, Carolina [RWTH Aachen University, Department of Diagnostic and Interventional Radiology, Aachen (Germany)

2015-10-15

The primary objective of the study was to identify early hematologic changes predictive for radiotherapy (RT)-associated genitourinary and gastrointestinal toxicity. In a group of 91 prostate cancer patients presenting for primary (n = 51) or postoperative (n = 40) curative RT, blood samples (blood count, acute phase proteins, and cytokines) were analyzed before (T1), three times during (T2-T4), and 6-8 weeks after (T5) radiotherapy. Before RT (baseline), on the last day (acute toxicity), a median of 2 months and 16 months (late toxicity) after RT, patients responded to a validated questionnaire (Expanded Prostate Cancer Index Composite). Acute score changes > 20 points and late changes > 10 points were considered clinically relevant. Radiotherapy resulted in significant changes of hematologic parameters, with the largest effect on lymphocytes (mean decrease of 31-45 %) and significant dependence on target volume. C-reactive protein (CRP) elevation > 5 mg/l and hemoglobin level decrease ≥ 5 G/1 at T2 were found to be independently predictive for acute urinary toxicity (p < 0.01, respectively). CRP elevation was predominantly detected in primary prostate RT (p = 0.02). Early lymphocyte level elevation ≥ 0.3G/l at T2 was protective against late urinary and bowel toxicity (p = 0.02, respectively). Other significant predictive factors for late bowel toxicity were decreasing hemoglobin levels (cut-off ≥ 5 G/l) at T2 (p = 0.04); changes of TNF-α (tumor necrosis factor; p = 0.03) and ferritin levels (p = 0.02) at T5. All patients with late bowel toxicity had interleukin (IL)-6 levels < 1.5 ng/l at T2 (63 % without; p = 0.01). Early hematologic changes during prostate cancer radiotherapy are predictive for late urinary and bowel toxicity. (orig.) [German] Das primaere Ziel der Studie war die Identifikation von fruehen haematologischen Veraenderungen mit praediktiver Bedeutung fuer radiotherapieassoziierte genitourinale und gastrointestinale Toxizitaet. In einer

Urgent need to reevaluate the latest World Health Organization guidelines for toxic inorganic substances in drinking water.

Science.gov (United States)

Frisbie, Seth H; Mitchell, Erika J; Sarkar, Bibudhendra

2015-08-13

The World Health Organization (WHO) has established guidelines for drinking-water quality that cover biological and chemical hazards from both natural and anthropogenic sources. In the most recent edition of Guidelines for Drinking-water Quality (2011), the WHO withdrew, suspended, did not establish, or raised guidelines for the inorganic toxic substances manganese, molybdenum, nitrite, aluminum, boron, nickel, uranium, mercury, and selenium. In this paper, we review these changes to the WHO drinking-water guidelines, examining in detail the material presented in the WHO background documents for each of these toxic substances. In some cases, these WHO background documents use literature reviews that do not take into account scientific research published within the last 10 or more years. In addition, there are instances in which standard WHO practices for deriving guidelines are not used; for example, rounding and other mathematical errors are made. According to published meeting reports from the WHO Chemical Aspects Working Group, the WHO has a timetable for revising some of its guidelines for drinking-water quality, but for many of these toxic substances the planned changes are minimal or will be delayed for as long as 5 years. Given the limited nature of the planned WHO revisions to the inorganic toxic substances and the extended timetable for these revisions, we suggest that governments, researchers, and other stakeholders might establish independent recommendations for inorganic toxic substances and possibly other chemicals to proactively protect public health, or at the very least, revert to previous editions of the Guidelines for Drinking-water Quality, which were more protective of public health.

Pesticide Toxicity Index: a tool for assessing potential toxicity of pesticide mixtures to freshwater aquatic organisms

Science.gov (United States)

Nowell, Lisa H.; Norman, Julia E.; Moran, Patrick W.; Martin, Jeffrey D.; Stone, Wesley W.

2014-01-01

Pesticide mixtures are common in streams with agricultural or urban influence in the watershed. The Pesticide Toxicity Index (PTI) is a screening tool to assess potential aquatic toxicity of complex pesticide mixtures by combining measures of pesticide exposure and acute toxicity in an additive toxic-unit model. The PTI is determined separately for fish, cladocerans, and benthic invertebrates. This study expands the number of pesticides and degradates included in previous editions of the PTI from 124 to 492 pesticides and degradates, and includes two types of PTI for use in different applications, depending on study objectives. The Median-PTI was calculated from median toxicity values for individual pesticides, so is robust to outliers and is appropriate for comparing relative potential toxicity among samples, sites, or pesticides. The Sensitive-PTI uses the 5th percentile of available toxicity values, so is a more sensitive screening-level indicator of potential toxicity. PTI predictions of toxicity in environmental samples were tested using data aggregated from published field studies that measured pesticide concentrations and toxicity to Ceriodaphnia dubia in ambient stream water. C. dubia survival was reduced to ≤ 50% of controls in 44% of samples with Median-PTI values of 0.1–1, and to 0% in 96% of samples with Median-PTI values > 1. The PTI is a relative, but quantitative, indicator of potential toxicity that can be used to evaluate relationships between pesticide exposure and biological condition.

Finite Difference Formulation for Prediction of Water Pollution

Science.gov (United States)

Johari, Hanani; Rusli, Nursalasawati; Yahya, Zainab

2018-03-01

Water is an important component of the earth. Human being and living organisms are demand for the quality of water. Human activity is one of the causes of the water pollution. The pollution happened give bad effect to the physical and characteristic of water contents. It is not practical to monitor all aspects of water flow and transport distribution. So, in order to help people to access to the polluted area, a prediction of water pollution concentration must be modelled. This study proposed a one-dimensional advection diffusion equation for predicting the water pollution concentration transport. The numerical modelling will be produced in order to predict the transportation of water pollution concentration. In order to approximate the advection diffusion equation, the implicit Crank Nicolson is used. For the purpose of the simulation, the boundary condition and initial condition, the spatial steps and time steps as well as the approximations of the advection diffusion equation have been encoded. The results of one dimensional advection diffusion equation have successfully been used to predict the transportation of water pollution concentration by manipulating the velocity and diffusion parameters.

Biochars made from agro-industrial by-products remove chlorine and lower water toxicity

Science.gov (United States)

Tzachristas, Andreas; Xirou, Maria; Manariotis, Ioannis D.; Dailianis, Stefanos; Karapanagioti, Hrissi K.

2016-04-01

Chlorination is the most common disinfection process for water and treated wastewater. For the industrial use of water in food production, chlorine can add undesired taste and odor to the final product. For this reason, dechlorination is desired for food industries that use municipal tap water. For treated wastewater discharge or reuse, chlorine can be toxic to the receiving aqueous systems and to the irrigated plants. In both the above cases, dechlorination is also required. Traditionally activated carbon has been used as the ideal material for the removal of chlorine. The main mechanisms that describe the interaction between activated carbon and HOCl or OCl- are described by the following equations (AWWA, 1990): HOCl + C* → C*O + H+ + Cl- (1), OCl- + C* → C*O + Cl- (2) Where C* and C*O represent the activated carbon surface and a surface oxide, respectively. The present study proposes the use of agro-industrial by-products for the production of biochars that will be used for dechlorination of tap-water used for food-industry production. Different raw materials such as malt spent rootlets, coffee residue, olive and grape seeds, etc. are used for the production of biochar. Various temperatures and air-to-solid ratios are tested for optimizing biochar production. Batch tests as well as a column test are employed to study the dechlorination efficiency and kinetics of the different raw and biochar materials as well as those of commercial activated carbons. As chlorine concentration increases the removal also increases linearily. After 1 and 24 hours of contact the chlorine relative removal efficiencies for the biochar made from olive seeds are 50 and 77 ± 4%, respectively. It seems that the removal kinetics are faster during the first hour; then, removal continues but with a slower rate. Most of the biochars tested (with 3 mg of solid in 20 mL of chlorine solution at initial concentration Co=1.5 mg/L) demonstrated removal efficiencies with an average of 9.4 ± 0

Identify the dominant variables to predict stream water temperature

Science.gov (United States)

Chien, H.; Flagler, J.

2016-12-01

Stream water temperature is a critical variable controlling water quality and the health of aquatic ecosystems. Accurate prediction of water temperature and the assessment of the impacts of environmental variables on water temperature variation are critical for water resources management, particularly in the context of water quality and aquatic ecosystem sustainability. The objective of this study is to measure stream water temperature and air temperature and to examine the importance of streamflow on stream water temperature prediction. The measured stream water temperature and air temperature will be used to test two hypotheses: 1) streamflow is a relatively more important factor than air temperature in regulating water temperature, and 2) by combining air temperature and streamflow data stream water temperature can be more accurately estimated. Water and air temperature data loggers are placed at two USGS stream gauge stations #01362357and #01362370, located in the upper Esopus Creek watershed in Phonecia, NY. The ARIMA (autoregressive integrated moving average) time series model is used to analyze the measured water temperature data, identify the dominant environmental variables, and predict the water temperature with identified dominant variable. The preliminary results show that streamflow is not a significant variable in predicting stream water temperature at both USGS gauge stations. Daily mean air temperature is sufficient to predict stream water temperature at this site scale.

Use of a (Quantitative) Structure-Activity Relationship [(Q)SAR] model to predict the toxicity of naphthenic acids

DEFF Research Database (Denmark)

Frank, Richard; Sanderson, Hans; Kavanagh, Richard

2010-01-01

Naphthenic acids (NAs) are a complex mixture of carboxylic acids that are natural constituents of oil sand found in north-eastern Alberta, Canada.  NAs are released and concentrated in the alkaline water used in the extraction of bitumen from oil sand sediment.  NAs have been identified...... as the principal toxic components of oil sands process-affected water (OSPW), and microbial degradation of lower molecular weight (MW) NAs decreases the toxicity of NA mixtures in OSPW.  Analysis by proton nuclear magnetic resonance spectroscopy indicated that larger, more cyclic NAs contain greater carboxylic...

Retrospective analysis of associations between water quality and toxic blooms of golden alga (Prymnesium parvum) in Texas reservoirs: Implications for understanding dispersal mechanisms and impacts of climate change

Science.gov (United States)

Patino, Reynaldo; Dawson, D.; VanLandeghem, Matthew M.

2014-01-01

Toxic blooms of golden alga (GA, Prymnesium parvum) in Texas typically occur in winter or early spring. In North America, they were first reported in Texas in the 1980s, and a marked range expansion occurred in 2001. Although there is concern about the influence of climate change on the future distribution of GA, factors responsible for past dispersals remain uncertain. To better understand the factors that influence toxic bloom dispersal in reservoirs, this study characterized reservoir water quality associated with toxic GA blooms since 2001, and examined trends in water quality during a 20-year period bracketing the 2001 expansion. Archived data were analyzed for six impacted and six nonimpacted reservoirs from two major Texas basins: Brazos River and Colorado River. Data were simplified for analysis by pooling spatially (across sampling stations) and temporally (winter, December-February) within reservoirs and generating depth-corrected (1 m) monthly values. Classification tree analysis [period of record (POR), 2001-2010] using salinity-associated variables (specific conductance, chloride, sulfate), dissolved oxygen (DO), pH, temperature, total hardness, potassium, nitrate+nitrite, and total phosphorus indicated that salinity best predicts the toxic bloom occurrence. Minimum estimated salinities for toxic bloom formation were 0.59 and 1.02 psu in Brazos and Colorado River reservoirs, respectively. Principal component analysis (POR, 2001-2010) indicated that GA habitat is best defined by higher salinity relative to nonimpacted reservoirs, with winter DO and pH also being slightly higher and winter temperature slightly lower in impacted reservoirs. Trend analysis, however, did not reveal monotonic changes in winter water quality of GA-impacted reservoirs during the 20-year period (1991-2010) bracketing the 2001 dispersal. Therefore, whereas minimum levels of salinity are required for GA establishment and toxic blooms in Texas reservoirs, the lack of trends in

Mimicking Daphnia magna bioassay performance by an electronic tongue for urban water quality control

Energy Technology Data Exchange (ETDEWEB)

Kirsanov, Dmitry, E-mail: d.kirsanov@gmail.com [Laboratory of Chemical Sensors, St. Petersburg State University, St. Petersburg (Russian Federation); Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation); Legin, Evgeny [Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation); Sensor Systems LLC, St. Petersburg (Russian Federation); Zagrebin, Anatoly; Ignatieva, Natalia; Rybakin, Vladimir [Institute of Limnology, Russian Academy of Sciences, St. Petersburg (Russian Federation); Legin, Andrey [Laboratory of Chemical Sensors, St. Petersburg State University, St. Petersburg (Russian Federation); Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation)

2014-05-01

Highlights: • -Daphnia magna bioassay can be simulated with multisensor system. • Urban water toxicity can be predicted from potentiometric ET data. • Independent test set validation confirms statistical significance of the results. - Abstract: Toxicity is one of the key parameters of water quality in environmental monitoring. However, being evaluated as a response of living beings (as their mobility, fertility, death rate, etc.) to water quality, toxicity can only be assessed with the help of these living beings. This imposes certain restrictions on toxicity bioassay as an analytical method: biotest organisms must be properly bred, fed and kept under strictly regulated conditions and duration of tests can be quite long (up to several days), thus making the whole procedure the prerogative of the limited number of highly specialized laboratories. This report describes an original application of potentiometric multisensor system (electronic tongue) when the set of electrochemical sensors was calibrated against Daphnia magna death rate in order to perform toxicity assessment of urban waters without immediate involvement of living creatures. PRM (partial robust M) and PLS (projections on latent structures) regression models based on the data from this multisensor system allowed for prediction of toxicity of unknown water samples in terms of biotests but in the fast and simple instrumental way. Typical errors of water toxicity predictions were below 20% in terms of Daphnia death rate which can be considered as a good result taking into account the complexity of the task.

Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

International Nuclear Information System (INIS)

Oliver, Ana López-Serrano; Croteau, Marie-Noële; Stoiber, Tasha L.; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R.; Luoma, Samuel N.

2014-01-01

Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. - Highlights: • AgNP coated with polyvinyl pyrrolidone (PVP), PVP-AgNP were efficiently assimilated by Lymnaea stagnalis. • Water chemistry has no influence on the dietary uptake of PVP-AgNP by snails. - L. Stagnalis assimilated PVP-AgNPs efficiently from food and water chemistry had no influence on their uptake and toxicity

Effects of water chemistry and surface contact on the toxicity of silver nanoparticles to Bacillus subtilis.

Science.gov (United States)

Yi, Jun; Cheng, Jinping

2017-07-01

The growing use of silver nanoparticles (AgNPs) has created concerns about its potential impacts on natural microbial communities. In this study, the physicochemical properties of AgNPs and its toxicity on natural bacteria Bacillus subtilis (B. subtilis) were investigated in aqueous conditions. The characterization data showed that AgNPs highly aggregated in aqueous conditions, and the hydrodynamic diameter of AgNPs in aqueous conditions was larger than its primary size. The studied AgNPs was less toxic to B. subtilis in estuarine water as compared to that in Milli-Q water and artificial seawater, which might be due to the observed enhanced aggregation of AgNPs in estuarine water. The toxicity of AgNPs to B. subtilis was greatly reduced when their surface contact was blocked by a dialysis membrane. Scanning electron microscope images showed that exposure contact to AgNPs resulted in damage of the microbial cell wall and enhanced formation of fibrillar structures. These results suggest that particle-cell contact is largely responsible for the observed toxicity of AgNPs in B. subtilis. This study can help to understand the potential impacts of AgNPs to natural microbes, especially in the complex aquatic environments.

Prediction of Chest Wall Toxicity From Lung Stereotactic Body Radiotherapy (SBRT)

Energy Technology Data Exchange (ETDEWEB)

Stephans, Kevin L., E-mail: stephak@ccf.org [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH (United States); Djemil, Toufik; Tendulkar, Rahul D. [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH (United States); Robinson, Cliff G. [Department of Radiation Oncology, Siteman Cancer Center, Washington University, St Louis, MO (United States); Reddy, Chandana A.; Videtic, Gregory M.M. [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH (United States)

2012-02-01

Purpose: To determine patient, tumor, and treatment factors related to the development of late chest wall toxicity after lung stereotactic body radiotherapy (SBRT). Methods and Materials: We reviewed a registry of 134 patients treated with lung SBRT to 60 Gy in 3 fractions who had greater than 1 year of clinical follow-up and no history of multiple treatments to the same lobe (n = 48). Patients were treated as per Radiation Therapy Oncology Group Protocol 0236 without specific chest wall avoidance criteria. The chest wall was retrospectively contoured. Thirty-two lesions measured less than 3 cm, and sixteen measured 3 to 5 cm. The median planning target volume was 29 cm{sup 3}. Results: With a median follow-up of 18.8 months, 10 patients had late symptomatic chest wall toxicity (4 Grade 1 and 6 Grade 2) at a median of 8.8 months after SBRT. No patient characteristics (age, diabetes, hypertension, peripheral vascular disease, or body mass index) were predictive for toxicity, whereas there was a trend for continued smoking (p = 0.066; odds ratio [OR], 4.4). Greatest single tumor dimension (p = 0.047; OR, 2.63) and planning target volume (p = 0.040; OR, 1.04) were correlated with toxicity, whereas distance from tumor edge to chest wall and gross tumor volume did not reach statistical significance. Volumes of chest wall receiving 30 Gy (V30) through 70 Gy (V70) were all highly significant, although this correlation weakened for V65 and V70 and maximum chest wall point dose only trended to significance (p = 0.06). On multivariate analysis, tumor volume was no longer correlated with toxicity and only V30 through V60 remained statistically significant. Conclusions: Tumor size and chest wall dosimetry are correlated to late chest wall toxicity. Only chest wall V30 through V60 remained significant on multivariate analysis. Restricting V30 to 30 cm{sup 3} or less and V60 to 3 cm{sup 3} or less should result in a 10% to 15% risk of late chest wall toxicity or lower.

In silico prediction of Tetrahymena pyriformis toxicity for diverse industrial chemicals with substructure pattern recognition and machine learning methods.

Science.gov (United States)

Cheng, Feixiong; Shen, Jie; Yu, Yue; Li, Weihua; Liu, Guixia; Lee, Philip W; Tang, Yun

2011-03-01

There is an increasing need for the rapid safety assessment of chemicals by both industries and regulatory agencies throughout the world. In silico techniques are practical alternatives in the environmental hazard assessment. It is especially true to address the persistence, bioaccumulative and toxicity potentials of organic chemicals. Tetrahymena pyriformis toxicity is often used as a toxic endpoint. In this study, 1571 diverse unique chemicals were collected from the literature and composed of the largest diverse data set for T. pyriformis toxicity. Classification predictive models of T. pyriformis toxicity were developed by substructure pattern recognition and different machine learning methods, including support vector machine (SVM), C4.5 decision tree, k-nearest neighbors and random forest. The results of a 5-fold cross-validation showed that the SVM method performed better than other algorithms. The overall predictive accuracies of the SVM classification model with radial basis functions kernel was 92.2% for the 5-fold cross-validation and 92.6% for the external validation set, respectively. Furthermore, several representative substructure patterns for characterizing T. pyriformis toxicity were also identified via the information gain analysis methods. Copyright © 2010 Elsevier Ltd. All rights reserved.

Toxic metals' concentration in water of Kriveljska Reka and its tributaries and influence of water there

International Nuclear Information System (INIS)

Lukic, D.; Zlatkovic, S.; Vuckovic, M.; Jovanovic, R.

2002-01-01

Kriveljska reka is near Bor, a big mining basin in East Serbia. This river is formed from two not so big rivers: Cerova reka and Valja Mare. Kriveljska reka flow past village Veliki Krivelj. Veliki Krivelj is one of the most important mining strip in Bor area. Therefore, Kriveljska reka is the reception for waste waters of some sections of Mining Basin Bor, situated on its banks. We will present to you concentrations of 7 toxic metals, pH-value and chemical oxygen demand in 8 points at Kriveljska reka and waste waters' influence on quality of this river's water. Based on our results, we can conclude that waste waters from Mining Basin Bor contaminate Kriveljska reka and at last we have a dead river. (author)

Pharmacogenetics predictive of response and toxicity in acute lymphoblastic leukemia therapy.

Science.gov (United States)

Mei, Lin; Ontiveros, Evelena P; Griffiths, Elizabeth A; Thompson, James E; Wang, Eunice S; Wetzler, Meir

2015-07-01

Acute lymphoblastic leukemia (ALL) is a relatively rare disease in adults accounting for no more than 20% of all cases of acute leukemia. By contrast with the pediatric population, in whom significant improvements in long term survival and even cure have been achieved over the last 30years, adult ALL remains a significant challenge. Overall survival in this group remains a relatively poor 20-40%. Modern research has focused on improved pharmacokinetics, novel pharmacogenetics and personalized principles to optimize the efficacy of the treatment while reducing toxicity. Here we review the pharmacogenetics of medications used in the management of patients with ALL, including l-asparaginase, glucocorticoids, 6-mercaptopurine, methotrexate, vincristine and tyrosine kinase inhibitors. Incorporating recent pharmacogenetic data, mainly from pediatric ALL, will provide novel perspective of predicting response and toxicity in both pediatric and adult ALL therapies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trophic State and Toxic Cyanobacteria Density in Optimization Modeling of Multi-Reservoir Water Resource Systems

Directory of Open Access Journals (Sweden)

Andrea Sulis

2014-04-01

Full Text Available The definition of a synthetic index for classifying the quality of water bodies is a key aspect in integrated planning and management of water resource systems. In previous works [1,2], a water system optimization modeling approach that requires a single quality index for stored water in reservoirs has been applied to a complex multi-reservoir system. Considering the same modeling field, this paper presents an improved quality index estimated both on the basis of the overall trophic state of the water body and on the basis of the density values of the most potentially toxic Cyanobacteria. The implementation of the index into the optimization model makes it possible to reproduce the conditions limiting water use due to excessive nutrient enrichment in the water body and to the health hazard linked to toxic blooms. The analysis of an extended limnological database (1996–2012 in four reservoirs of the Flumendosa-Campidano system (Sardinia, Italy provides useful insights into the strengths and limitations of the proposed synthetic index.

Fractionation of fulvic acid by iron and aluminum oxides: influence on copper toxicity to Ceriodaphnia dubia

Science.gov (United States)

Smith, Kathleen S.; Ranville, James F.; Lesher, Emily K.; Diedrich, Daniel J.; McKnight, Diane M.; Sofield, Ruth M.

2014-01-01

This study examines the effect on aquatic copper toxicity of the chemical fractionation of fulvic acid (FA) that results from its association with iron and aluminum oxyhydroxide precipitates. Fractionated and unfractionated FAs obtained from streamwater and suspended sediment were utilized in acute Cu toxicity tests on ,i>Ceriodaphnia dubia. Toxicity test results with equal FA concentrations (6 mg FA/L) show that the fractionated dissolved FA was 3 times less effective at reducing Cu toxicity (EC50 13 ± 0.6 μg Cu/L) than were the unfractionated dissolved FAs (EC50 39 ± 0.4 and 41 ± 1.2 μg Cu/L). The fractionation is a consequence of preferential sorption of molecules having strong metal-binding (more aromatic) moieties to precipitating Fe- and Al-rich oxyhydroxides, causing the remaining dissolved FA to be depleted in these functional groups. As a result, there is more bioavailable dissolved Cu in the water and hence greater potential for Cu toxicity to aquatic organisms. In predicting Cu toxicity, biotic ligand models (BLMs) take into account dissolved organic carbon (DOC) concentration; however, unless DOC characteristics are accounted for, model predictions can underestimate acute Cu toxicity for water containing fractionated dissolved FA. This may have implications for water-quality criteria in systems containing Fe- and Al-rich sediment, and in mined and mineralized areas in particular. Optical measurements, such as specific ultraviolet absorbance at 254 nm (SUVA254), show promise for use as spectral indicators of DOC chemical fractionation and inferred increased Cu toxicity.

Toxicity reduction for pharmaceuticals mixture in water by electron beam irradiation

International Nuclear Information System (INIS)

Boiani, Nathalia Fonseca; Tominaga, Flavio Kiyoshi; Borrely, Sueli Ivone

2015-01-01

The incorrect disposal of products is committing the environment quality once the aquatic environment is the main vehicle for dispersion of pollutants. Among the highlighted contaminants there are the pharmaceuticals, which are also released to the aquatic environment through the domestic sewage, hospitals and effluents. The monitoring of these pharmaceuticals in the environment has grown, showing many of them as persistent pollutants. Pharmaceuticals from different therapeutic classes have been detected in domestic sewage, surface water and groundwater around the world. Several studies evidenced Fluoxetine Hydrochloride residues in waters. Another important product is the Propranolol, used for heart disease treatments as far as fluoxetine is applied for treating mental diseases. The objective of this study was to apply the radiation processing for the abatement of pollutant in waters. Electron beam accelerator was used during irradiation of the mixture (Propranolol + Fluoxetine Hydrochloride) in aqueous solution. Acute toxicity assays were carried out for Vibrio fischeri marine bacterium, 15 minutes exposure. The results showed that irradiation (2.5kGy and 5.0kGy) enhanced the average effective concentration of the mixture, which means reduction of toxicity (56.34%, 55.70% respectively). Inverse effect was obtained with 7.5 kGy and 10 kGy. (author)

Toxicity reduction for pharmaceuticals mixture in water by electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Boiani, Nathalia Fonseca; Tominaga, Flavio Kiyoshi; Borrely, Sueli Ivone, E-mail: flavio_tominaga@hotmail.com, E-mail: sborrely@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

The incorrect disposal of products is committing the environment quality once the aquatic environment is the main vehicle for dispersion of pollutants. Among the highlighted contaminants there are the pharmaceuticals, which are also released to the aquatic environment through the domestic sewage, hospitals and effluents. The monitoring of these pharmaceuticals in the environment has grown, showing many of them as persistent pollutants. Pharmaceuticals from different therapeutic classes have been detected in domestic sewage, surface water and groundwater around the world. Several studies evidenced Fluoxetine Hydrochloride residues in waters. Another important product is the Propranolol, used for heart disease treatments as far as fluoxetine is applied for treating mental diseases. The objective of this study was to apply the radiation processing for the abatement of pollutant in waters. Electron beam accelerator was used during irradiation of the mixture (Propranolol + Fluoxetine Hydrochloride) in aqueous solution. Acute toxicity assays were carried out for Vibrio fischeri marine bacterium, 15 minutes exposure. The results showed that irradiation (2.5kGy and 5.0kGy) enhanced the average effective concentration of the mixture, which means reduction of toxicity (56.34%, 55.70% respectively). Inverse effect was obtained with 7.5 kGy and 10 kGy. (author)

Assessment of acute toxicity of water soluble fraction of diesel on ...

African Journals Online (AJOL)

Acute toxicity of water soluble fraction (WSF) of diesel fuel was assessed by evaluating its effects on growth of two marine microalgae, Isochrysis and Chaetoceros. Pure cultures of each of the two microalgae were exposed to concentrations of 0% (controls), 5%, 10%, 15% and 20% of diesel WSF (in triplicates) and allowed ...

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

Energy Technology Data Exchange (ETDEWEB)

Markich, Scott J., E-mail: smarkich@optusnet.com.au

2013-01-15

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{sub 3} L{sup −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{sub 3} L{sup −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 μg L{sup −1} U at 20 mg CaCO{sub 3} L{sup −1} hardness, increasing to 547 μg L{sup −1} U at 400 mg CaCO{sub 3} L{sup −1} hardness), cell surface binding affinity (log K = 6.25 at 20 mg CaCO{sub 3} L{sup −1} hardness, decreasing to log K = 5.64 at 400 mg CaCO{sub 3} L{sup −1} hardness) and accumulation (the concentration factor decreased from 63 at 20 mg CaCO{sub 3} L{sup −1} hardness to 15 at 400 mg CaCO{sub 3} L{sup −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{sub 2}{sup 2+}, UO{sub 2}OH{sup +}, UO{sub 2}(OH){sub 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{sup 2+}/Mg{sup 2+} and UO{sub 2}{sup 2+} (and/or UO{sub 2}OH{sup +}) 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{sub 2}{sup 2+} (and/or UO{sub 2}OH{sup +}) at the plant/water interface (boundary layer

Model Prediction Control For Water Management Using Adaptive Prediction Accuracy

NARCIS (Netherlands)

Tian, X.; Negenborn, R.R.; Van Overloop, P.J.A.T.M.; Mostert, E.

2014-01-01

In the field of operational water management, Model Predictive Control (MPC) has gained popularity owing to its versatility and flexibility. The MPC controller, which takes predictions, time delay and uncertainties into account, can be designed for multi-objective management problems and for

Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff.

Science.gov (United States)

Anderson, Brian S; Phillips, Bryn M; Voorhees, Jennifer P; Cahn, Michael

2017-05-15

Urban stormwater and agriculture irrigation runoff contain a complex mixture of contaminants that are often toxic to adjacent receiving waters. Runoff may be treated with simple systems designed to promote sorption of contaminants to vegetation and soils and promote infiltration. Two example systems are described: a bioswale treatment system for urban stormwater treatment, and a vegetated drainage ditch for treating agriculture irrigation runoff. Both have similar attributes that reduce contaminant loading in runoff: vegetation that results in sorption of the contaminants to the soil and plant surfaces, and water infiltration. These systems may also include the integration of granulated activated carbon as a polishing step to remove residual contaminants. Implementation of these systems in agriculture and urban watersheds requires system monitoring to verify treatment efficacy. This includes chemical monitoring for specific contaminants responsible for toxicity. The current paper emphasizes monitoring of current use pesticides since these are responsible for surface water toxicity to aquatic invertebrates.

Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

Science.gov (United States)

López-Serrano Oliver, Ana; Croteau, Marie-Noële; Stoiber, Tasha L.; Tejamaya, Mila; Römer, Isabella; Lead, Jamie R.; Luoma, Samuel N.

2014-01-01

Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important.

Toxicity of copper to the marine amphipod Allorchestes compressa in the presence of water- and lipid-soluble ligands

Energy Technology Data Exchange (ETDEWEB)

Ahsanullah, M; Florence, T M

1984-12-01

Acute toxicity tests were carried out on the marine amphipod Allorchestes compressa Dana using copper sulfate and some organocopper complexes. For copper sulfate, 96 h LC50 values of 0.11 and 0.5 mg Cu/liter were determined for the juveniles and the adults, respectively. Juveniles were about 4.5 times more sensitive to copper than adults Organocopper complexes were tested on adults only. The three water soluble ligands nitrotriacetic acid, 8-hydroxyquinoline-5-sulfoic acid and tannic acid ameliorated copper toxicity by decreasing the concentration of free ionic copper while lipid-soluble ligands such as oxine and potassium ethylxanthogenate increased copper toxicity, presumably as a result of the complexes diffusing through the cell membrane and participating in injurious reaction. The copper complex with 2,9-dimethyl-1,10-phenanthroline was the most toxic complex tested. It is suggested that the presence of these ligands in the receiving water should be taken into consideration when establishing water quality criteria. 19 references, 2 figures, 3 tables.

In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: the relative toxic effect of sediment versus water contamination.

Science.gov (United States)

Faria, Mafalda S; Lopes, Ricardo J; Nogueira, António J A; Soares, Amadeu M V M

2007-09-01

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.

Toxicity studies of the water extract from the calyces of Hibiscus ...

African Journals Online (AJOL)

Acute and chronic toxicities of the water extract from calyces of Hibiscus sabdariffa were studied in male and female rats. After 14 days of a single oral administration of test substance 5,000 mg/kg body weight, measurement of the body and organ weights, necropsy and health monitoring were performed. No signs and ...

Cumulative toxicity of neonicotinoid insecticide mixtures to Chironomus dilutus under acute exposure scenarios.

Science.gov (United States)

Maloney, Erin M; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

2017-11-01

Extensive agricultural use of neonicotinoid insecticide products has resulted in the presence of neonicotinoid mixtures in surface waters worldwide. Although many aquatic insect species are known to be sensitive to neonicotinoids, the impact of neonicotinoid mixtures is poorly understood. In the present study, the cumulative toxicities of binary and ternary mixtures of select neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) were characterized under acute (96-h) exposure scenarios using the larval midge Chironomus dilutus as a representative aquatic insect species. Using the MIXTOX approach, predictive parametric models were fitted and statistically compared with observed toxicity in subsequent mixture tests. Single-compound toxicity tests yielded median lethal concentration (LC50) values of 4.63, 5.93, and 55.34 μg/L for imidacloprid, clothianidin, and thiamethoxam, respectively. Because of the similar modes of action of neonicotinoids, concentration-additive cumulative mixture toxicity was the predicted model. However, we found that imidacloprid-clothianidin mixtures demonstrated response-additive dose-level-dependent synergism, clothianidin-thiamethoxam mixtures demonstrated concentration-additive synergism, and imidacloprid-thiamethoxam mixtures demonstrated response-additive dose-ratio-dependent synergism, with toxicity shifting from antagonism to synergism as the relative concentration of thiamethoxam increased. Imidacloprid-clothianidin-thiamethoxam ternary mixtures demonstrated response-additive synergism. These results indicate that, under acute exposure scenarios, the toxicity of neonicotinoid mixtures to C. dilutus cannot be predicted using the common assumption of additive joint activity. Indeed, the overarching trend of synergistic deviation emphasizes the need for further research into the ecotoxicological effects of neonicotinoid insecticide mixtures in field settings, the development of better toxicity models for neonicotinoid mixture

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Yasuo; Mayer, D.W.; Argo, R.S.

1982-01-01

Models are presented to estimate the migration of toxic contaminants in coastal waters. Ocean current is simulated by the vertically-averaged, finite element, two-demensional model known as CAFE-I with the Galerkin weighted residual technique. The refraction of locally generated waves or swells is simulated by the wave refraction model, LO3D. Using computed current, depth, and wave characteristics, the finite element model, FETRA, simulated sediment and contaminant transport in coastal waters, estuaries and rivers. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interaction, and the mechanism governing the transport, deposition, and resuspension of contaminated sediment. Several simple equations such as the unsteady, advection-diffusion equation, the equation for noncohesive-sediment load due to wind-induced waves in offshore and surf zones, and the equation for sediment-radionuclide transport simulation were solved during the preliminary testing of the model. (Kato, T.)

Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

Science.gov (United States)

Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

2015-07-01

The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. © 2015 SETAC.

Amelioration of chronic fluoride toxicity by calcium and fluoride-free water in rats.

Science.gov (United States)

Shankar, Priyanka; Ghosh, Sudip; Bhaskarachary, K; Venkaiah, K; Khandare, Arjun L

2013-07-14

The study was undertaken to explore the amelioration of chronic fluoride (F) toxicity (with low and normal Ca) in rats. The study was conducted in two phases. In phase I (6 months), seventy-six Wistar, weanling male rats were assigned to four treatment groups: normal-Ca (0·5 %) diet (NCD), Ca+F - ; low-Ca (0·25 %) diet (LCD), Ca - F - ; NCD +100 parts per million (ppm) F water, Ca+F+; LCD +100 ppm F water, Ca - F+. In phase II (reversal experiment, 3 months), LCD was replaced with the NCD. Treatment groups Ca+F+ and Ca - F+ were divided into two subgroups to compare the effect of continuation v. discontinuation along with Ca supplementation on reversal of chronic F toxicity. In phase I, significantly reduced food efficiency ratio (FER), body weight gain (BWG), faecal F excretion, serum Ca and increased bone F deposition were observed in the treatment group Ca - F+. Reduced serum 25-hydroxy-vitamin D3, increased 1,25-dihydroxy-vitamin D3 and up-regulation of Ca-sensing receptor, vitamin D receptor and S100 Ca-binding protein G (S100G) were observed in treatment groups Ca - F - and Ca - F+. In phase II (reversal phase), FER, BWG and serum Ca in treatment groups Ca - F+/Ca+F - and Ca - F+/Ca+F+ were still lower, as compared with other groups. However, other variables were comparable. Down-regulation of S100G was observed in F-fed groups (Ca+F+/Ca+F+ and Ca - F+/Ca+F+) in phase II. It is concluded that low Ca aggravates F toxicity, which can be ameliorated after providing adequate Ca and F-free water. However, chronic F toxicity can interfere with Ca absorption by down-regulating S100G expression irrespective of Ca nutrition.

Chemical mixtures in untreated water from public-supply wells in the U.S. - Occurrence, composition, and potential toxicity

Energy Technology Data Exchange (ETDEWEB)

Toccalino, Patricia L., E-mail: ptocca@usgs.gov [U.S. Geological Survey (USGS), 6000 J Street, Placer Hall, Sacramento, California 95819 (United States); Norman, Julia E., E-mail: jnorman@usgs.gov [USGS, 2130 SW 5th Avenue, Portland, Oregon 97201 (United States); Scott, Jonathon C., E-mail: jon@usgs.gov [USGS, 202 NW 66th Street, Oklahoma City, Oklahoma 73116 (United States)

2012-08-01

Chemical mixtures are prevalent in groundwater used for public water supply, but little is known about their potential health effects. As part of a large-scale ambient groundwater study, we evaluated chemical mixtures across multiple chemical classes, and included more chemical contaminants than in previous studies of mixtures in public-supply wells. We (1) assessed the occurrence of chemical mixtures in untreated source-water samples from public-supply wells, (2) determined the composition of the most frequently occurring mixtures, and (3) characterized the potential toxicity of mixtures using a new screening approach. The U.S. Geological Survey collected one untreated water sample from each of 383 public wells distributed across 35 states, and analyzed the samples for as many as 91 chemical contaminants. Concentrations of mixture components were compared to individual human-health benchmarks; the potential toxicity of mixtures was characterized by addition of benchmark-normalized component concentrations. Most samples (84%) contained mixtures of two or more contaminants, each at concentrations greater than one-tenth of individual benchmarks. The chemical mixtures that most frequently occurred and had the greatest potential toxicity primarily were composed of trace elements (including arsenic, strontium, or uranium), radon, or nitrate. Herbicides, disinfection by-products, and solvents were the most common organic contaminants in mixtures. The sum of benchmark-normalized concentrations was greater than 1 for 58% of samples, suggesting that there could be potential for mixtures toxicity in more than half of the public-well samples. Our findings can be used to help set priorities for groundwater monitoring and suggest future research directions for drinking-water treatment studies and for toxicity assessments of chemical mixtures in water resources. - Highlights: Black-Right-Pointing-Pointer We assessed mixtures in untreated groundwater samples from public

Toxicity of waters from the Rochester Embayment Area of Concern to the plankton species Pseudokirchneriella subcapitata and Ceriodaphnia dubia

Science.gov (United States)

Baldigo, Barry P.; Duffy, Brian T.; Smith, Alexander J.; George, Scott D.

2016-01-01

The lower Genesee River and Rochester Embayment of Lake Ontario are a designated Area of Concern (AOC) under the binational Great Lakes Water Quality Agreement. The “degradation of phytoplankton and zooplankton populations” or plankton Beneficial Use Impairment (BUI) was classified as unknown and in need of further assessment in this AOC because water quality data suggested plankton communities could be effected and community data were either unavailable or indicated impacts. The plankton BUI may now be obsolete because local contaminant sources have been largely eliminated. The present study was conducted between July 2013 and August 2014 to assess the BUI-removal criteria: “AOC plankton bioassays confirm that toxicity in ambient waters (i.e., no growth inhibition) is not significantly higher than comparable non-AOC controls”. Acute and chronic toxicity of waters from 13 sites were quantified seasonally using standardized bioassays with the green alga Pseudokirchneriella subcapitata and water flea Ceriodaphnia dubia to test the hypothesis that toxicity of waters from AOC sites was not higher than that of waters from comparable non-AOC reference sites. Survival and reproduction of C. dubia did not differ significantly between site types, systems, or months. The growth of P. subcapitata did not differ between site types, but differed among systems and months. All results indicate that waters from AOC sites were no more toxic to both plankton species than waters from reference sites. Assuming test species represent natural plankton assemblages, water quality should not negatively affect survival and growth of resident plankton populations in the Rochester Embayment AOC.

Chemical mixtures in untreated water from public-supply wells in the U.S. — Occurrence, composition, and potential toxicity

International Nuclear Information System (INIS)

Toccalino, Patricia L.; Norman, Julia E.; Scott, Jonathon C.

2012-01-01

Chemical mixtures are prevalent in groundwater used for public water supply, but little is known about their potential health effects. As part of a large-scale ambient groundwater study, we evaluated chemical mixtures across multiple chemical classes, and included more chemical contaminants than in previous studies of mixtures in public-supply wells. We (1) assessed the occurrence of chemical mixtures in untreated source-water samples from public-supply wells, (2) determined the composition of the most frequently occurring mixtures, and (3) characterized the potential toxicity of mixtures using a new screening approach. The U.S. Geological Survey collected one untreated water sample from each of 383 public wells distributed across 35 states, and analyzed the samples for as many as 91 chemical contaminants. Concentrations of mixture components were compared to individual human-health benchmarks; the potential toxicity of mixtures was characterized by addition of benchmark-normalized component concentrations. Most samples (84%) contained mixtures of two or more contaminants, each at concentrations greater than one-tenth of individual benchmarks. The chemical mixtures that most frequently occurred and had the greatest potential toxicity primarily were composed of trace elements (including arsenic, strontium, or uranium), radon, or nitrate. Herbicides, disinfection by-products, and solvents were the most common organic contaminants in mixtures. The sum of benchmark-normalized concentrations was greater than 1 for 58% of samples, suggesting that there could be potential for mixtures toxicity in more than half of the public-well samples. Our findings can be used to help set priorities for groundwater monitoring and suggest future research directions for drinking-water treatment studies and for toxicity assessments of chemical mixtures in water resources. - Highlights: ► We assessed mixtures in untreated groundwater samples from public-supply wells. ► A screening

Integrating the fish embryo toxicity test as triad element for sediment toxicity assessment based on the water framework directive approach

Energy Technology Data Exchange (ETDEWEB)

Bartzke, Mariana [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Dept. Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Leipzig (Germany); Delov, Vera [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Ecotoxicology, Fraunhofer Inst. for Molecular Biology and Applied Ecology IME, Aachen (Germany); Stahlschmidt-Allner, Petra; Allner, Bernhard [Gobio GmbH, Aarbergen/Kettenbach (Germany); Oehlmann, Joerg [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany)

2010-04-15

Purpose: The objective of this study was to complement analyses according to the European Union Water Framework Directive (WFD) with a sediment toxicity analysis as part of an integrated river assessment. To this end, Hessian water courses were analyzed using the sediment quality triad concept according to Chapman with chemical analyses, in situ effect evaluations, and ecotoxicological assessments. For the ecotoxicological assessment (fish embryo toxicity test with Danio rerio), a new evaluation scheme was developed, the fish teratogenicity index (FTI), that allows for a classification of sediments into ecological quality classes compliant to the WFD. Materials and methods sediment and macrozoobenthos samples were taken from tributaries of the rivers Fulda and Lahn. Sediments were characterized regarding particle size, carbon, heavy metals, and polyaromatic hydrocarbon content. Macroinvertebrate samples were taken via multi-habitat sampling. The fish embryo toxicity test with D. rerio was conducted as a contact assay on the basis of DIN 38415-6. Results and discussion The integrated assessment indicated a significant influence of heavy metals and carbon content on macroinvertebrate communities. The bioaccessibility of sediment pollutants were clearly demonstrated by the FTI, which showed a wide range of adverse effects. A significant linear relationship between metals and the FTI was detected. However, there was no statistically significant evidence that macroinvertebrate communities were affected by the hydromorphological quality clements at the sampling sites. Conclusions The new scheme for the assessment of fish embryo toxicity test was successfully applied. The results suggest that sediment compounds impact macroinvertebrate communities and early development of fish. It demonstrates that the quality of sediments should be evaluated on a routine basis as part of an integrated river assessment. (orig.)

Predictive factors for acute and late urinary toxicity after permanent interstitial brachytherapy in Japanese patients

International Nuclear Information System (INIS)

Tanimoto, Ryuta; Bekku, Kensuke; Katayama, Norihisa

2013-01-01

The objectives of this study were to describe the frequency of and to determine predictive factors associated with Radiation Therapy Oncology Group urinary toxicity in prostate brachytherapy patients. From January 2004 to April 2011, 466 consecutive Japanese patients underwent permanent iodine-125-seed brachytherapy (median follow up 48 months). International Prostate Symptom Score and Radiation Therapy Oncology Group toxicity data were prospectively collected. Prostate volume, International Prostate Symptom Score before and after brachytherapy, and postimplant analysis were examined for an association with urinary toxicity, defined as Radiation Therapy Oncology Group urinary toxicity of Grade 1 or higher. Logistic regression analysis was used to examine the factors associated with urinary toxicity. The rate of Radiation Therapy Oncology Group urinary toxicity grade 1 or higher at 1, 6, 12, 24, 36 and 48 months was 67%, 40%, 21%, 31%, 27% and 28%, respectively. Grade 2 or higher urinary toxicity was less than 1% at each time-point. International Prostate Symptom Score was highest at 3 months and returned to normal 12 months after brachytherapy. On multivariate analysis, patients with a larger prostate size, greater baseline International Prostate Symptom Score, higher prostate V100, higher prostate V150, higher prostate D90 and a greater number of seeds had more acute urinary toxicities at 1 month and 12 months after brachytherapy. On multivariate analysis, significant predictors for urinary toxicity at 1 month and 12 months were a greater baseline International Prostate Symptom Score and prostate V100. Most urinary symptoms are tolerated and resolved within 12 months after prostate brachytherapy. Acute and late urinary toxicity after brachytherapy is strongly related to the baseline International Prostate Symptom Score and prostate V100. (author)

Disturbances to metal partitioning during toxicity testing of iron(II)-rich estuarine pore waters and whole sediments.

Science.gov (United States)

Simpson, Stuart L; Batley, Graeme E

2003-02-01

Metal partitioning is altered when suboxic estuarine sediments containing Fe(II)-rich pore waters are disturbed during collection, preparation, and toxicity testing. Experiments with model Fe(II)-rich pore waters demonstrated the rates at which adsorptive losses of Cd, Cu, Ni, Mn, Pb, and Zn occur upon exposure to air. Experiments with Zn-contaminated estuarine sediments demonstrated large and often unpredictable changes to metal partitioning during sediment storage, removal of organisms, and homogenization before testing. Small modifications to conditions, such as aeration of overlying waters, caused large changes to the metal partitioning. Disturbances caused by sediment collection required many weeks for reestablishment of equilibrium. Bioturbation by benthic organisms led to oxidation of pore-water Fe(II) and lower Zn fluxes because of the formation of Fe hydroxide precipitates that adsorb pore-water Zn. For five weeks after the addition of organisms to sediments, Zn fluxes increased slowly as the organisms established themselves in the sediments, indicating that the establishment of equilibrium was not rapid. The results are discussed in terms of the dynamic nature of suboxic, Fe(II)-rich estuarine sediments, how organisms perturb their environment, and the importance of understanding chemistry in toxicity testing with whole sediments or pore water. Recommendations are provided for the handling of sediments for toxicity testing.

Comparative analysis of pharmaceuticals versus industrial chemicals acute aquatic toxicity classification according to the United Nations classification system for chemicals. Assessment of the (Q)SAR predictability of pharmaceuticals acute aquatic toxicity and their predominant acute toxic mode-of-action

DEFF Research Database (Denmark)

Sanderson, Hans; Thomsen, Marianne

2009-01-01

data. Pharmaceuticals were found to be more frequent than industrial chemicals in GHS category III. Acute toxicity was predictable (>92%) using a generic (Q)SAR ((Quantitative) Structure Activity Relationship) suggesting a narcotic MOA. Analysis of model prediction error suggests that 68...

Toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures

Science.gov (United States)

Mwangi, Joseph N.; Wang, Ning; Ritts, Andrew; Kunz, James L.; Ingersoll, Christopher G.; Li, Hao; Deng, Baolin

2011-01-01

Silicon carbide nanowires (SiCNW) are insoluble in water. When released into an aquatic environment, SiCNW would likely accumulate in sediment. The objective of this study was to assess the toxicity of SiCNW to four freshwater sediment-dwelling organisms: amphipods (Hyalella azteca), midges (Chironomus dilutus), oligochaetes (Lumbriculus variegatus), and mussels (Lampsilis siliquoidea). Amphipods were exposed to either sonicated or nonsonicated SiCNW in water (1.0 g/L) for 48 h. Midges, mussels, and oligochaetes were exposed only to sonicated SiCNW in water for 96 h. In addition, amphipods were exposed to sonicated SiCNW in whole sediment for 10 d (44% SiCNW on dry wt basis). Mean 48-h survival of amphipods exposed to nonsonicated SiCNW in water was not significantly different from the control, whereas mean survival of amphipods exposed to sonicated SiCNW in two 48-h exposures (0 or 15% survival) was significantly different from the control (90 or 98% survival). In contrast, no effect of sonicated SiCNW was observed on survival of midges, mussels, or oligochaetes. Survival of amphipods was not significantly reduced in 10-d exposures to sonicated SiCNW either mixed in the sediment or layered on the sediment surface. However, significant reduction in amphipod biomass was observed with the SiCNW either mixed in sediment or layered on the sediment surface, and the reduction was more pronounced for SiCNW layered on the sediment. These results indicated that, under the experimental conditions, nonsonicated SiCNW in water were not acutely toxic to amphipods, sonicated SiCNW in water were acutely toxic to the amphipods, but not to other organisms tested, and sonicated SiCNW in sediment affected the growth but not the survival of amphipods.

Analysis of 'wet-landscape' surface water fractions using medaka embryo-toxicity bioassay

Energy Technology Data Exchange (ETDEWEB)

Peters, L. E.; McConkey, B. J.; Vanden Heuvel, M. R. (Waterloo, Univ., Dept, of Biology, Waterloo, ON (Canada)); MacKinnon, M. D. (Syncrude Canada Ltd., Fort McMurray, AB (Canada)) Munkittricx, K. (Environment Canada, Burlington, ON (Canada))

1998-01-01

The self-sustaining biological potential of Syncrude's 'wetland-scape' waste disposal method was evaluated by testing water extracts from experimental pits of different ages and fine tailings/natural water compositions. This waste disposal method involves capping fine tailings with a layer of surface water. Preliminary estimates suggests a higher incidence of mortality and deformity in Japanese Medaka embryos incubated in pit waters containing elevated concentrations of naphthenates. Another study on adult perch stocked in the demonstration pit indicated the presence of PAHs in the fish bile at biologically relevant concentrations. This study was designed to determine the causative agents of the fish embryo toxicity and the level of concentrations at which chronic effects occur. The water extracts were fractionated into acid (containing naphthenates) and base-neutral (containing PAHs) components and tested using the Japanese Medaka bioassay. Endpoints measured were the presence of deformity, hatch success, swim-bladder inflation, length at hatch and time to mortality. HPLC analysis showed that PAHs were present at concentrations in the part/billion and the parts/million range. This is being taken as an indication that PAHs are not directly responsible for the observed toxicity to the embryos.

An integrated approach to improved toxicity prediction for the safety assessment during preclinical drug development using Hep G2 cells

International Nuclear Information System (INIS)

Noor, Fozia; Niklas, Jens; Mueller-Vieira, Ursula; Heinzle, Elmar

2009-01-01

Efficient and accurate safety assessment of compounds is extremely important in the preclinical development of drugs especially when hepatotoxicty is in question. Multiparameter and time resolved assays are expected to greatly improve the prediction of toxicity by assessing complex mechanisms of toxicity. An integrated approach is presented in which Hep G2 cells and primary rat hepatocytes are compared in frequently used cytotoxicity assays for parent compound toxicity. The interassay variability was determined. The cytotoxicity assays were also compared with a reliable alternative time resolved respirometric assay. The set of training compounds consisted of well known hepatotoxins; amiodarone, carbamazepine, clozapine, diclofenac, tacrine, troglitazone and verapamil. The sensitivity of both cell systems in each tested assay was determined. Results show that careful selection of assay parameters and inclusion of a kinetic time resolved assay improves prediction for non-metabolism mediated toxicity using Hep G2 cells as indicated by a sensitivity ratio of 1. The drugs with EC 50 values 100 μM or lower were considered toxic. The difference in the sensitivity of the two cell systems to carbamazepine which causes toxicity via reactive metabolites emphasizes the importance of human cell based in-vitro assays. Using the described system, primary rat hepatocytes do not offer advantage over the Hep G2 cells in parent compound toxicity evaluation. Moreover, respiration method is non invasive, highly sensitive and allows following the time course of toxicity. Respiration assay could serve as early indicator of changes that subsequently lead to toxicity.

TIC-Tox: A preliminary discussion on identifying the forcing agents of DBP-mediated toxicity of disinfected water.

Science.gov (United States)

Plewa, Michael J; Wagner, Elizabeth D; Richardson, Susan D

2017-08-01

The disinfection of drinking water is a major public health achievement; however, an unintended consequence of disinfection is the generation of disinfection by-products (DBPs). Many of the identified DBPs exhibit in vitro and in vivo toxicity, generate a diversity of adverse biological effects, and may be hazards to the public health and the environment. Only a few DBPs are regulated by several national and international agencies and it is not clear if these regulated DBPs are the forcing agents that drive the observed toxicity and their associated health effects. In this study, we combine analytical chemical and biological data to resolve the forcing agents associated with mammalian cell cytotoxicity of drinking water samples from three cities. These data suggest that the trihalomethanes (THMs) and haloacetic acids may be a small component of the overall cytotoxicity of the organic material isolated from disinfected drinking water. Chemical classes of nitrogen-containing DBPs, such as the haloacetonitriles and haloacetamides, appear to be the major forcing agents of toxicity in these samples. These findings may have important implications for the design of epidemiological studies that primarily rely on the levels of THMs to define DBP exposure among populations. The TIC-Tox approach constitutes a beginning step in the process of identifying the forcing agents of toxicity in disinfected water. Copyright © 2017. Published by Elsevier B.V.

Toxicity of diesel water accommodated fraction toward microalgae, Pseudokirchneriella subcapitata and Chlorella sp. MM3.

Science.gov (United States)

Ramadass, Kavitha; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

2017-08-01

Diesel is a commonly used fuel and a key pollutant on water surface through leaks and accidental spills, thus creating risk directly to planktons as well as other aquatic organisms. We assessed the toxicty of diesel and its water accommodated fraction (WAF) towards two microalgal species, Pseudokirchneriella subcapitata and Chlorella sp. MM3. The toxicity criteria included were: chlorophyll a content as a growth parameter and induction of enzyme activities linked to oxidative stress. Increase in concentrations of diesel or its WAF significantly increased toxicity towards growth, measured in terms of chlorophyll a content in both the algae. Activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in response to addition of diesel or diesel WAF to the microalgal cultures were dose-dependent. Diesel WAF was more toxic than diesel itself, suggesting that use of WAF may be more relevant for environmental risk assessment of diesel. The overall response of the antioxidant enzymes to toxicants' stress followed the order: POX≥SOD>CAT. The present study clearly demonstrated the use of SOD, POX and CAT as suitable biomarkers for assessing diesel pollution in aquatic ecosystem. Copyright © 2017 Elsevier Inc. All rights reserved.

COMPUTER-BASED PREDICTION OF TOXICITY USING THE ELECTRON-CONFORMATIONAL METHOD. APPLICATION TO FRAGRANCE ALLERGENS AND OTHER ENVIRONMENTAL POLLUTANTS

Directory of Open Access Journals (Sweden)

Natalia N. Gorinchoy

2012-06-01

Full Text Available The electron-conformational (EC method is employed for the toxicophore (Tph identification and quantitative prediction of toxicity using the training set of 24 compounds that are considered as fragrance allergens. The values of a=LD50 in oral exposure of rats were chosen as a measure of toxicity. EC parameters are evaluated on the base of conformational analysis and ab initio electronic structure calculations (including solvent influence. The Tph consists of four sites which in this series of compounds are represented by three carbon and one oxygen atoms, but may be any other atoms that have the same electronic and geometric features within the tolerance limits. The regression model taking into consideration the Tph flexibility, anti-Tph shielding, and influence of out-of-Tph functional groups predicts well the experimental values of toxicity (R2 = 0.93 with a reasonable leaveone- out cross-validation.

Relationship between water temperature predictability and aquatic ...

African Journals Online (AJOL)

Macroinvertebrate taxonomic turnover across seasons was higher for sites having lower water temperature predictability values than for sites with higher predictability, while temporal partitioning was greater at sites with greater temperature variability. Macroinvertebrate taxa responded in a predictable manner to changes in ...

Prediction of acute toxicity of cadmium and lead to zebrafish larvae by using a refined toxicokinetic-toxicodynamic model

International Nuclear Information System (INIS)

Gao, Yongfei; Feng, Jianfeng; Zhu, Lin

2015-01-01

Highlights: • We developed a BLM-aided TK-TD model that considers the effects of H"+. • The time-course metal concentration in larvae was well described by the TK model. • The time-course survival of zebrafish larvae was well simulated by the TD model. - Abstract: The biotic ligand model (BLM) and the toxicokinetic-toxicodynamic (TK-TD) model are essential in predicting the acute toxicity of metals in various species and exposure conditions; however, these models are usually separately utilized. In this study, a mechanistic TK-TD model was developed to predict the acute toxicity of 10"−"6 M Cd and 10"−"6 M Pb to zebrafish (Danio rerio) larvae. The novel approach links the BLM with relevant TK processes to simulate the bioaccumulation processes of Cd or Pb as a function of the maximum uptake rate of each metal, the affinity constants, and the concentrations of free metal ions and H"+ in test solutions. Results showed that the refined TK-TD model can accurately predict the accumulation and acute toxicity of Cd and Pb to zebrafish larvae at pH 5.5, 6.5, and 7.0.

Prediction of acute toxicity of cadmium and lead to zebrafish larvae by using a refined toxicokinetic-toxicodynamic model

Energy Technology Data Exchange (ETDEWEB)

Gao, Yongfei; Feng, Jianfeng, E-mail: fengjf@nankai.edu.cn; Zhu, Lin, E-mail: zhulin@nankai.edu.cn

2015-12-15

Highlights: • We developed a BLM-aided TK-TD model that considers the effects of H{sup +}. • The time-course metal concentration in larvae was well described by the TK model. • The time-course survival of zebrafish larvae was well simulated by the TD model. - Abstract: The biotic ligand model (BLM) and the toxicokinetic-toxicodynamic (TK-TD) model are essential in predicting the acute toxicity of metals in various species and exposure conditions; however, these models are usually separately utilized. In this study, a mechanistic TK-TD model was developed to predict the acute toxicity of 10{sup −6} M Cd and 10{sup −6} M Pb to zebrafish (Danio rerio) larvae. The novel approach links the BLM with relevant TK processes to simulate the bioaccumulation processes of Cd or Pb as a function of the maximum uptake rate of each metal, the affinity constants, and the concentrations of free metal ions and H{sup +} in test solutions. Results showed that the refined TK-TD model can accurately predict the accumulation and acute toxicity of Cd and Pb to zebrafish larvae at pH 5.5, 6.5, and 7.0.

Chemical mixtures in untreated water from public-supply wells in the U.S.--occurrence, composition, and potential toxicity.

Science.gov (United States)

Toccalino, Patricia L; Norman, Julia E; Scott, Jonathon C

2012-08-01

Chemical mixtures are prevalent in groundwater used for public water supply, but little is known about their potential health effects. As part of a large-scale ambient groundwater study, we evaluated chemical mixtures across multiple chemical classes, and included more chemical contaminants than in previous studies of mixtures in public-supply wells. We (1) assessed the occurrence of chemical mixtures in untreated source-water samples from public-supply wells, (2) determined the composition of the most frequently occurring mixtures, and (3) characterized the potential toxicity of mixtures using a new screening approach. The U.S. Geological Survey collected one untreated water sample from each of 383 public wells distributed across 35 states, and analyzed the samples for as many as 91 chemical contaminants. Concentrations of mixture components were compared to individual human-health benchmarks; the potential toxicity of mixtures was characterized by addition of benchmark-normalized component concentrations. Most samples (84%) contained mixtures of two or more contaminants, each at concentrations greater than one-tenth of individual benchmarks. The chemical mixtures that most frequently occurred and had the greatest potential toxicity primarily were composed of trace elements (including arsenic, strontium, or uranium), radon, or nitrate. Herbicides, disinfection by-products, and solvents were the most common organic contaminants in mixtures. The sum of benchmark-normalized concentrations was greater than 1 for 58% of samples, suggesting that there could be potential for mixtures toxicity in more than half of the public-well samples. Our findings can be used to help set priorities for groundwater monitoring and suggest future research directions for drinking-water treatment studies and for toxicity assessments of chemical mixtures in water resources. Published by Elsevier B.V.

The impact of iodinated X-ray contrast agents on formation and toxicity of disinfection by-products in drinking water.

Science.gov (United States)

Jeong, Clara H; Machek, Edward J; Shakeri, Morteza; Duirk, Stephen E; Ternes, Thomas A; Richardson, Susan D; Wagner, Elizabeth D; Plewa, Michael J

2017-08-01

The presence of iodinated X-ray contrast media (ICM) in source waters is of high concern to public health because of their potential to generate highly toxic disinfection by-products (DBPs). The objective of this study was to determine the impact of ICM in source waters and the type of disinfectant on the overall toxicity of DBP mixtures and to determine which ICM and reaction conditions give rise to toxic by-products. Source waters collected from Akron, OH were treated with five different ICMs, including iopamidol, iopromide, iohexol, diatrizoate and iomeprol, with or without chlorine or chloramine disinfection. The reaction product mixtures were concentrated with XAD resins and the mammalian cell cytotoxicity and genotoxicity of the reaction mixture concentrates was measured. Water containing iopamidol generated an enhanced level of mammalian cell cytotoxicity and genotoxicity after disinfection. While chlorine disinfection with iopamidol resulted in the highest cytotoxicity overall, the relative iopamidol-mediated increase in toxicity was greater when chloramine was used as the disinfectant compared with chlorine. Four other ICMs (iopromide, iohexol, diatrizoate, and iomeprol) expressed some cytotoxicity over the control without any disinfection, and induced higher cytotoxicity when chlorinated. Only iohexol enhanced genotoxicity compared to the chlorinated source water. Copyright © 2017. Published by Elsevier B.V.

Serum Creatinine Versus Plasma Methotrexate Levels to Predict Toxicities in Children Receiving High-dose Methotrexate.

Science.gov (United States)

Tiwari, Priya; Thomas, M K; Pathania, Subha; Dhawan, Deepa; Gupta, Y K; Vishnubhatla, Sreenivas; Bakhshi, Sameer

2015-01-01

Facilities for measuring methotrexate (MTX) levels are not available everywhere, potentially limiting administration of high-dose methotrexate (HDMTX). We hypothesized that serum creatinine alteration after HDMTX administration predicts MTX clearance. Overall, 122 cycles in 50 patients of non-Hodgkin lymphoma or acute lymphoblastic leukemia aged ≤18 years receiving HDMTX were enrolled prospectively. Plasma MTX levels were measured at 12, 24, 36, 48, 60, and 72 hours; serum creatinine was measured at baseline, 24, 48, and 72 hours. Correlation of plasma MTX levels with creatinine levels and changes in creatinine from baseline (Δ creatinine) were evaluated. Plasma MTX levels at 72 hours showed positive correlation with serum creatinine at 48 hours (P = .011) and 72 hours (P = .013) as also Δ creatinine at 48 hours (P = .042) and 72 hours (P = .045). However, cut-off value of either creatinine or Δ creatinine could not be established to reliably predict delayed MTX clearance. Greater than 50% Δ creatinine at 48 and 72 hours significantly predicted grade 3/4 leucopenia (P = .036 and P = .001, respectively) and thrombocytopenia (P = .012 and P = .009, respectively) but not mucositis (P = .827 and P = .910, respectively). Delayed MTX elimination did not predict any grade 3/4 toxicity. In spite of demonstration of significant correlation between serum creatinine and Δ creatinine with plasma MTX levels at 72 hours, cut-off value of either variable to predict MTX delay could not be established. Thus, either of these cannot be used as a surrogate for plasma MTX estimation. Interestingly, Δ creatinine effectively predicted hematological toxicities, which were not predicted by delayed MTX clearance.

Toxicity of methylmercury injected into eggs when dissolved in water versus corn oil

Science.gov (United States)

Heinz, G.H.; Hoffman, D.J.; Klimstra, J.D.; Stebbins, K.R.; Kondrad, S.L.

2011-01-01

In a previous study, the embryotoxicity of methylmercury dissolved in corn oil was compared among 26 species of birds. Corn oil is not soluble in the water-based matrix that constitutes the albumen of an egg. To determine whether the use of corn oil limited the usefulness of this earlier study, a comparison was made of the embryotoxicity of methylmercury dissolved in corn oil versus water. Mallard (Anas platyrhynchos) and chicken (Gallus gallus) eggs were injected with methylmercury chloride dissolved in corn oil or water to achieve concentrations of 0, 0.2, 0.4, 0.8, and 1.6??g/g mercury in the egg on a wet weight basis. Hatching success at each dose of mercury was compared between the two solvents. For mallards, 16.4% of the eggs injected with 1.6??g/g mercury dissolved in water hatched, which was statistically lower than the 37.6% hatch rate of eggs injected with 1.6??g/g mercury dissolved in corn oil, but no differences in hatching success were observed between corn oil and water at any of the other doses. With chicken eggs, no significant differences occurred in percentage hatch of eggs between corn oil and water at any of the mercury doses. Methylmercury dissolved in corn oil seems to have a toxicity to avian embryos similar to that of does methylmercury dissolved in water. Consequently, the results from the earlier study that described the toxicity of methylmercury dissolved in corn oil to avian embryos were probably not compromised by the use of corn oil as a solvent. ?? 2011 SETAC.

A Methylmercury Prediction Too For Surface Waters Across The Contiguous United States (Invited)

Science.gov (United States)

Krabbenhoft, D. P.; Booth, N.; Lutz, M.; Fienen, M. N.; Saltman, T.

2009-12-01

About 20 years ago, researchers at a few locations across the globe discovered high levels of mercury in fish from remote settings lacking any obvious mercury source. We now know that for most locations atmospheric deposition is the dominant mercury source, and that mercury methylation is the key process that translates low mercury loading rates into relatively high levels in top predators of aquatic food webs. Presently, almost all US states have advisories for elevated levels of mercury in sport fish, and as a result there is considerable public awareness and concern for this nearly ubiquitous contaminant issue. In some states, “statewide” advisories have been issued because elevated fish mercury levels are so common, or the state has no effective way to monitor thousands of lakes, reservoirs, wetlands, and streams. As such, resource managers and public health officials have limited options for informing the public on of where elevated mercury concentrations in sport fish are more likely to occur than others. This project provides, for the first time, a national map of predicted (modeled) methylmercury concentrations in surface waters, which is the most toxic and bioaccumulative form of mercury in the environment. The map is the result of over two decades of research that resulted in the formulation of conceptual models of the mercury methylation process, which is strongly governed by environmental conditions - specifically hydrologic landscapes and water quality. The resulting predictive map shows clear regional trends in the distribution of methylmercury concentrations in surface waters. East of the Mississippi, the Gulf and southeastern Atlantic coast, the northeast, the lower Mississippi valley, and Great Lakes area are predicted to have generally higher environmental methylmercury levels. Higher-elevation, well-drained areas of Appalachia are predicted to have relatively lower methylmercury abundance. Other than the prairie pothole region, in the western

Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams

Science.gov (United States)

Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara J.; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L.

2018-01-01

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water—atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim—were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May–June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July–August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most

STUDY ON REMOVAL OF TOXIC METALS FROM WATER USING BIOMATERIALS USING AS AN ADSORBENTS

OpenAIRE

R. S. Dubey*, Triptaran Kaur

2017-01-01

In today’s date when we talk about purity of things nothing can be placed in the category of being pure. From air to water to soil to food everything is polluted. Pollution can be defined as presence of inappropriate material which may cause harm to living beings. Here we talked about the contaminated water and find out the harmful ingredients present in it. I have studied the presence of toxic metals like copper, cadmium and chromium in our water. Water being the most essential part of once ...

Effects of Cd and Ni toxicity to Ceratophyllum demersum under environmentally relevant conditions in soft and hard water including a German lake

Energy Technology Data Exchange (ETDEWEB)

Andresen, Elisa, E-mail: Elisa.Andresen@uni-konstanz.de [University of Konstanz, Department of Biology, D-78457 Konstanz (Germany); Opitz, Judith, E-mail: Daniela.Opitz@uni-konstanz.de [University of Konstanz, Department of Biology, D-78457 Konstanz (Germany); Thomas, George, E-mail: George.Thomas@uni-konstanz.de [University of Konstanz, Department of Biology, D-78457 Konstanz (Germany); Stärk, Hans-Joachim, E-mail: Ha-Jo.Staerk@ufz.de [UFZ – Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstr. 15, D-04318 Leipzig (Germany); Dienemann, Holger, E-mail: Holger.Dienemann@smul.sachsen.de [Saxon State Company for Environment and Agriculture, Business Domain 5 (Laboratory), Department 53, Bitterfelder Str. 25, D-04849 Bad Düben (Germany); Jenemann, Kerstin, E-mail: Kerstin.Jenemann@smul.sachsen.de [Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie, Abteilung Wasser, Boden, Wertstoffe, Zur Wetterwarte 11, D-01109 Dresden (Germany); Dickinson, Bryan C., E-mail: Bryan.Dickinson@gmail.com [Harvard University, Department of Chemistry and Chemical Biology, 12 Oxford Street, Cambridge, MA 02138 (United States); Küpper, Hendrik, E-mail: Hendrik.Kuepper@uni-konstanz.de [University of Konstanz, Department of Biology, D-78457 Konstanz (Germany); University of South Bohemia, Faculty of Biological Sciences and Institute of Physical Biology, Branišovská 31, CZ-370 05 České Budejovice (Czech Republic)

2013-10-15

Highlights: •Hardly any macrophytic growth occurred in an oligotrophic hard water lake in Germany. •All parameters were optimal, besides elevated, nanomolar concentrations of Ni and Cd. •We cultivated submerged macrophytes in real and simulated hard and soft lake water. •Nanomolar Cd and Ni inhibited the plants’ photosynthetic light reactions in soft water. •The inhibition was synergistic, i.e. stronger than the addition of Cd and Ni effects. -- Abstract: Even essential trace elements are phytotoxic over a certain threshold. In this study, we investigated whether heavy metal concentrations were responsible for the nearly complete lack of submerged macrophytes in an oligotrophic lake in Germany. We cultivated the rootless aquatic model plant Ceratophyllum demersum under environmentally relevant conditions like sinusoidal light and temperature cycles and a low plant biomass to water volume ratio. Experiments lasted for six weeks and were analysed by detailed measurements of photosynthetic biophysics, pigment content and hydrogen peroxide production. We established that individually non-toxic cadmium (3 nM) and slightly toxic nickel (300 nM) concentrations became highly toxic when applied together in soft water, severely inhibiting photosynthetic light reactions. Toxicity was further enhanced by phosphate limitation (75 nM) in soft water as present in many freshwater habitats. In the investigated lake, however, high water hardness limited the toxicity of these metal concentrations, thus the inhibition of macrophytic growth in the lake must have additional reasons. The results showed that synergistic heavy metal toxicity may change ecosystems in many more cases than estimated so far.

Effects of Cd and Ni toxicity to Ceratophyllum demersum under environmentally relevant conditions in soft and hard water including a German lake

International Nuclear Information System (INIS)

Andresen, Elisa; Opitz, Judith; Thomas, George; Stärk, Hans-Joachim; Dienemann, Holger; Jenemann, Kerstin; Dickinson, Bryan C.; Küpper, Hendrik

2013-01-01

Highlights: •Hardly any macrophytic growth occurred in an oligotrophic hard water lake in Germany. •All parameters were optimal, besides elevated, nanomolar concentrations of Ni and Cd. •We cultivated submerged macrophytes in real and simulated hard and soft lake water. •Nanomolar Cd and Ni inhibited the plants’ photosynthetic light reactions in soft water. •The inhibition was synergistic, i.e. stronger than the addition of Cd and Ni effects. -- Abstract: Even essential trace elements are phytotoxic over a certain threshold. In this study, we investigated whether heavy metal concentrations were responsible for the nearly complete lack of submerged macrophytes in an oligotrophic lake in Germany. We cultivated the rootless aquatic model plant Ceratophyllum demersum under environmentally relevant conditions like sinusoidal light and temperature cycles and a low plant biomass to water volume ratio. Experiments lasted for six weeks and were analysed by detailed measurements of photosynthetic biophysics, pigment content and hydrogen peroxide production. We established that individually non-toxic cadmium (3 nM) and slightly toxic nickel (300 nM) concentrations became highly toxic when applied together in soft water, severely inhibiting photosynthetic light reactions. Toxicity was further enhanced by phosphate limitation (75 nM) in soft water as present in many freshwater habitats. In the investigated lake, however, high water hardness limited the toxicity of these metal concentrations, thus the inhibition of macrophytic growth in the lake must have additional reasons. The results showed that synergistic heavy metal toxicity may change ecosystems in many more cases than estimated so far

Assessing the phototransformation of diclofenac, clofibric acid and naproxen in surface waters: Model predictions and comparison with field data.

Science.gov (United States)

Avetta, Paola; Fabbri, Debora; Minella, Marco; Brigante, Marcello; Maurino, Valter; Minero, Claudio; Pazzi, Marco; Vione, Davide

2016-11-15

Phototransformation is important for the fate in surface waters of the pharmaceuticals diclofenac (DIC) and naproxen (NAP) and for clofibric acid (CLO), a metabolite of the drug clofibrate. The goal of this paper is to provide an overview of the prevailing photochemical processes, which these compounds undergo in the different conditions found in freshwater environments. The modelled photochemical half-life times of NAP and DIC range from a few days to some months, depending on water conditions (chemistry and depth) and on the season. The model indicates that direct photolysis is the dominant degradation pathway of DIC and NAP in sunlit surface waters, and potentially toxic cyclic amides were detected as intermediates of DIC direct phototransformation. With modelled half-life times in the month-year range, CLO is predicted to be more photostable than DIC or NAP and to be degraded mainly by reaction with the • OH radical and with the triplet states of chromophoric dissolved organic matter ( 3 CDOM*). The CLO intermediates arising from these processes and detected in this study (hydroquinone and 4-chlorophenol) are, respectively, a chronic toxicant to aquatic organisms and a possible carcinogen for humans. Hydroquinone is formed with only ∼5% yield upon CLO triplet-sensitised transformation, but it is highly toxic for algae and crustaceans. In contrast, the formation yield of 4-chlorophenol reaches ∼50% upon triplet sensitisation and ∼10% by · OH reaction. The comparison of model predictions with field data from a previous study yielded a very good agreement in the case of DIC and, when using 4-carboxybenzophenone as proxy for triplet sensitisation by CDOM, a good agreement was found for CLO as well. In the case of NAP, the comparison with field data suggests that its direct photolysis quantum yield approaches or even falls below the lower range of literature values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toxicity assessment and modelling of Moringa oleifera seeds in water purification by whole cell bioreporter.

Science.gov (United States)

Al-Anizi, Ali Adnan; Hellyer, Maria Theresa; Zhang, Dayi

2014-06-01

Moringa oleifera has been used as a coagulation reagent for drinking water purification, especially in developing countries such as Malawi. This research revealed the cytoxicity and genotoxicity of M. oleifera by Acinetobacter bioreporter. The results indicated that significant cytoxicity effects were observed when the powdered M. oleifera seeds concentration is from 1 to 50 mg/L. Through direct contact, ethanolic-water extraction and hexane extraction, the toxic effects of hydrophobic and hydrophilic components in M. oleifera seeds were distinguished. It suggested that the hydrophobic lipids contributed to the dominant cytoxicity, consequently resulting in the dominant genotoxicity in the water-soluble fraction due to limited dissolution when the M. oleifera seeds granule concentration was from 10 to 1000 mg/L. Based on cytoxicity and genotoxicity model, the LC50 and LC90 of M. oleifera seeds were 8.5 mg/L and 300 mg/L respectively and their genotoxicity was equivalent to 8.3 mg mitomycin C per 1.0 g dry M. oleifera seed. The toxicity of M. oleifera has also remarkable synergistic effects, suggesting whole cell bioreporter as an appropriate and complementary tool to chemical analysis for environmental toxicity assessment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rules for distinguishing toxicants that cause type I and type II narcosis syndromes.

OpenAIRE

Veith, G D; Broderius, S J

1990-01-01

Narcosis is a nonspecific reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. The vast majority of industrial organic chemicals can be characterized by a baseline structure-toxicity relationship as developed for diverse aquatic organisms, using only the n-octanol/water partition coefficient as a descriptor. There are, however, many apparent narcotic chemicals that are more toxic than baseline narcosis predicts. Some of these chemical...

Prediction of clinical toxicity in locally advanced head and neck cancer patients by radio-induced apoptosis in peripheral blood lymphocytes (PBLs)

International Nuclear Information System (INIS)

Bordón, Elisa; Henríquez-Hernández, Luis Alberto; Lara, Pedro C; Ruíz, Ana; Pinar, Beatriz; Rodríguez-Gallego, Carlos; Lloret, Marta

2010-01-01

Head and neck cancer is treated mainly by surgery and radiotherapy. Normal tissue toxicity due to x-ray exposure is a limiting factor for treatment success. Many efforts have been employed to develop predictive tests applied to clinical practice. Determination of lymphocyte radio-sensitivity by radio-induced apoptosis arises as a possible method to predict tissue toxicity due to radiotherapy. The aim of the present study was to analyze radio-induced apoptosis of peripheral blood lymphocytes in head and neck cancer patients and to explore their role in predicting radiation induced toxicity. Seventy nine consecutive patients suffering from head and neck cancer, diagnosed and treated in our institution, were included in the study. Toxicity was evaluated using the Radiation Therapy Oncology Group scale. Peripheral blood lymphocytes were isolated and irradiated at 0, 1, 2 and 8 Gy during 24 hours. Apoptosis was measured by flow cytometry using annexin V/propidium iodide. Lymphocytes were marked with CD45 APC-conjugated monoclonal antibody. Radiation-induced apoptosis increased in order to radiation dose and fitted to a semi logarithmic model defined by two constants: α and β. α, as the origin of the curve in the Y axis determining the percentage of spontaneous cell death, and β, as the slope of the curve determining the percentage of cell death induced at a determined radiation dose, were obtained. β value was statistically associated to normal tissue toxicity in terms of severe xerostomia, as higher levels of apoptosis were observed in patients with low toxicity (p = 0.035; Exp(B) 0.224, I.C.95% (0.060-0.904)). These data agree with our previous results and suggest that it is possible to estimate the radiosensitivity of peripheral blood lymphocytes from patients determining the radiation induced apoptosis with annexin V/propidium iodide staining. β values observed define an individual radiosensitivity profile that could predict late toxicity due to radiotherapy

Toxicity of granular activated carbon treated coal gasification water as determined by the Microtox test and Escherichia coli.

Science.gov (United States)

Makino, Y; Adams, J C; McTernan, W F

1986-01-01

The Microtox assay and various parameters (growth, ATP concentration and electrochemical detection) of Escherichia coli were used to assess the toxicity of various levels of granular activated carbon treated coal gasification process water. The generation time of E. coli was statistically significantly slower at the level of 50 percent treatment than any other level of treatment. No differences were seen for ATP concentration per cell or in the electrochemical detection methods for any level treatment. There was a very high correlation between total organic carbon removal by GAC treatment and reduction in toxicity as measured by the Microtox system. However, even the treated water which had 91 percent of the TOC removed was still highly toxic.

Barley root hair growth and morphology in soil, sand, and water solution media and relationship with nickel toxicity.

Science.gov (United States)

Lin, Yanqing; Allen, Herbert E; Di Toro, Dominic M

2016-08-01

Barley, Hordeum vulgare (Doyce), was grown in the 3 media of soil, hydroponic sand solution (sand), and hydroponic water solution (water) culture at the same environmental conditions for 4 d. Barley roots were scanned, and root morphology was analyzed. Plants grown in the 3 media had different root morphology and nickel (Ni) toxicity response. Root elongations and total root lengths followed the sequence soil > sand > water. Plants grown in water culture were more sensitive to Ni toxicity and had greater root hair length than those from soil and sand cultures, which increased root surface area. The unit root surface area as root surface area per centimeter of length of root followed the sequence water > sand > soil and was found to be related with root elongation. Including the unit root surface area, the difference in root elongation and 50% effective concentration were diminished, and percentage of root elongations can be improved with a root mean square error approximately 10% for plants grown in different media. Because the unit root surface area of plants in sand culture is closer to that in soil culture, the sand culture method, not water culture, is recommended for toxicity parameter estimation. Environ Toxicol Chem 2016;35:2125-2133. © 2016 SETAC. © 2016 SETAC.

Developing predictions of in vivo developmental toxicity of ToxCast chemicals using mouse embryonic stem cells.

Science.gov (United States)

Developing predictions of in vivo developmental toxicity of ToxCast chemicals using mouse embryonic stem cells S. Hunter, M. Rosen, M. Hoopes, H. Nichols, S. Jeffay, K. Chandler1, Integrated Systems Toxicology Division, National Health and Environmental Effects Research Labor...

Heavy metal concentrations and toxicity in water and sediment from stormwater ponds and sedimentation tanks.

Science.gov (United States)

Karlsson, Kristin; Viklander, Maria; Scholes, Lian; Revitt, Mike

2010-06-15

Sedimentation is a widely used technique in structural best management practices to remove pollutants from stormwater. However, concerns have been expressed about the environmental impacts that may be exerted by the trapped pollutants. This study has concentrated on stormwater ponds and sedimentation tanks and reports on the accumulated metal concentrations (Cd, Cr, Ni, Pb, and Zn) and the associated toxicity to the bacteria Vibrio fischeri. The metal concentrations are compared with guidelines and the toxicity results are assessed in relation to samples for which metal concentrations either exceed or conform to these values. The water phase metal concentrations were highest in the ponds whereas the sedimentation tanks exhibited a distinct decrease towards the outlet. However, none of the water samples demonstrated toxicity even though the concentrations of Cu, Pb, and Zn exceeded the threshold values for the compared guidelines. The facilities with higher traffic intensities had elevated sediment concentrations of Cr, Cu, Ni, and Zn which increased towards the outlet for the sedimentation tanks in agreement with the highest percentage of fine particles. The sediments in both treatment facilities exhibited the expected toxic responses in line with their affinity for heavy metals but the role of organic carbon content is highlighted. Copyright 2010 Elsevier B.V. All rights reserved.

Genomics and the prediction of xenobiotic toxicity

International Nuclear Information System (INIS)

Meyer, Urs-A.; Gut, Josef

2002-01-01

The systematic identification and functional analysis of human genes is revolutionizing the study of disease processes and the development and rational use of drugs. It increasingly enables medicine to make reliable assessments of the individual risk to acquire a particular disease, raises the number and specificity of drug targets and explains interindividual variation of the effectiveness and toxicity of drugs. Mutant alleles at a single gene locus for more than 20 drug metabolizing enzymes are some of the best studied individual risk factors for adverse drug reactions and xenobiotic toxicity. Increasingly, genetic polymorphisms of transporter and receptor systems are also recognized as causing interindividual variation in drug response and drug toxicity. However, pharmacogenetic and toxicogenetic factors rarely act alone; they produce a phenotype in concert with other variant genes and with environmental factors. Environmental factors may affect gene expression in many ways. For instance, numerous drugs induce their own and the metabolism of other xenobiotics by interacting with nuclear receptors such as AhR, PPAR, PXR and CAR. Genomics is providing the information and technology to analyze these complex situations to obtain individual genotypic and gene expression information to assess the risk of toxicity

Haloacetonitriles: metabolism and toxicity.

Science.gov (United States)

Lipscomb, John C; El-Demerdash, Ebtehal; Ahmed, Ahmed E

2009-01-01

The haloacetonitriles (HANs) exist in drinking water exclusively as byproducts of disinfection. HANs are found in drinking water more often, and in higher concentrations, when surface water is treated by chloramination. Human exposure occurs through consumption of finished drinking water; oral and dermal contact also occurs, and results from showering, swimming and other activities. HANs are reactive and are toxic to gastrointestinal tissues following oral administration. Such toxicity is characterized by GSH depletion, increased lipid peroxidation, and covalent binding of HAN-associated radioactivity to gut tissues. The presence of GSH in cells is an important protective mechanism against HAN toxicity; depletion of cellular GSH results in increased toxicity. Some studies have demonstrated an apparently synergistic effect between ROS and HAN administration, that may help explain effects observed in GI tissues. ROS are produced in gut tissues, and in vitro evidence indicates that ROS may contribute to the degradation and formation of reactive intermediates from HANs. The rationale for ROS involvement may involve HAN-induced depletion of GSH and the role of GSH in scavenging ROS. In addition to effects on GI tissues, studies show that HAN-derived radiolabel is found covalently bound to proteins and DNA in several organs and tissues. The addition of antioxidants to biologic systems protects against HAN-induced DNA damage. The protection offered by antioxidants supports the role of oxidative stress and the potential for a threshold in han-induced toxicity. However, additional data are needed to substantiate evidence for such a threshold. HANs are readily absorbed from the GI tract and are extensively metabolized. Elimination occurs primarily in urine, as unconjugated one-carbon metabolites. Evidence supports the involvement of mixed function oxidases, the cytochrome P450 enzyme family and GST, in HAN metabolism. Metabolism represents either a detoxification or

Selection of a bioassay battery to assess toxicity in the affluents and effluents of three water-treatment plants

Directory of Open Access Journals (Sweden)

Paola Bohórquez-Echeverry

2012-08-01

Full Text Available The assessment of water quality includes the analysis of both physical-chemical and microbiological parameters. However,none of these evaluates the biological effect that can be generated in ecosystems or humans. In order to define the most suitable organismsto evaluate the toxicity in the affluent and effluent of three drinking-water treatment plants, five acute toxicity bioassays were used,incorporating three taxonomic groups of the food chain. Materials and methods. The bioassays used were Daphnia magna and Hydraattenuata as animal models, Lactuca sativa and Pseudokirchneriella subcapitata as plant models, and Photobacterium leioghnathi asbacterial model. To meet this objective, selection criteria of the organisms evaluated and cluster analysis were used to identify the mostsensitive in the affluent and effluent of each plant. Results. All organisms are potentially useful in the assessment of water quality bymeeting four essential requirements and 17 desirable requirements equivalent to 100% acceptability, except P. leioghnathi which doesnot meet two essential requirements that are the IC50 for the toxic reference and the confidence interval. The animal, plant and bacterialmodels showed different levels of sensitivity at the entrance and exit of the water treatment systems. Conclusions. H. attenuata, P.subcapitata and P. leioghnathi were the most effective organisms in detecting toxicity levels in the affluents and D. magna, P. subcapitataand P. leioghnathi in the effluents.

Assessment of the chemical toxicity of long-lived radionuclides on the basis of Who guidelines for drinking-water quality

International Nuclear Information System (INIS)

Renaud-Salis, V.; Menetrier, F.; Leudet, A.; Flury-Herard, A.

2003-01-01

The current assessment of health risks related to long lived radionuclides waste management is not complete if accounting only for radiological toxicity aspects. Although such an approach is justified for a large number of radionuclides of concern, it nevertheless cannot be exclusive and generalised: the chemical toxicity should be considered for radionuclides with a radioactive half-life exceeding 10 5 years. When assessing the chemical or radiological toxicity of a radionuclide, a reference dose applied to drinking water consumption (0.1 mSv/year) can be compared to existing toxicological data. Such an approach has been used by the World Health Organization for natural uranium, for which a guideline value in drinking water derived from its chemical toxicity (2 μg/l) is recommended. WHO's approach is used here for illustrating that the potential chemical toxicity of an element is to be considered for assessing health risks related to long-lived radionuclides. (authors)

Overview of Chronic Oral Toxicity Values for Chemicals Present in Hydraulic Fracturing Fluids, Flowback and Produced Waters

Science.gov (United States)

as part of EPA's Hydraulic Fracturing Drinking Water Assessment, EPA is summarizing existing toxicity data for chemicals reported to be used in hydraulic fracturing fluids and/or found in flowback or produced waters from hydraulically fractured wells

Concentration addition and independent action model: Which is better in predicting the toxicity for metal mixtures on zebrafish larvae.

Science.gov (United States)

Gao, Yongfei; Feng, Jianfeng; Kang, Lili; Xu, Xin; Zhu, Lin

2018-01-01

The joint toxicity of chemical mixtures has emerged as a popular topic, particularly on the additive and potential synergistic actions of environmental mixtures. We investigated the 24h toxicity of Cu-Zn, Cu-Cd, and Cu-Pb and 96h toxicity of Cd-Pb binary mixtures on the survival of zebrafish larvae. Joint toxicity was predicted and compared using the concentration addition (CA) and independent action (IA) models with different assumptions in the toxic action mode in toxicodynamic processes through single and binary metal mixture tests. Results showed that the CA and IA models presented varying predictive abilities for different metal combinations. For the Cu-Cd and Cd-Pb mixtures, the CA model simulated the observed survival rates better than the IA model. By contrast, the IA model simulated the observed survival rates better than the CA model for the Cu-Zn and Cu-Pb mixtures. These findings revealed that the toxic action mode may depend on the combinations and concentrations of tested metal mixtures. Statistical analysis of the antagonistic or synergistic interactions indicated that synergistic interactions were observed for the Cu-Cd and Cu-Pb mixtures, non-interactions were observed for the Cd-Pb mixtures, and slight antagonistic interactions for the Cu-Zn mixtures. These results illustrated that the CA and IA models are consistent in specifying the interaction patterns of binary metal mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection of toxic compounds in real water samples using a conductometric tyrosinase biosensor

International Nuclear Information System (INIS)

Anh, Tuan Mai; Dzyadevych, Sergei V.; Prieur, Nicolas; Duc, Chien Nguyen; Pham, T.D.; Renault, Nicole Jaffrezic; Chovelon, Jean-Marc

2006-01-01

A conductometric tyrosinase biosensor for the detection of some toxic compounds including diuron, atrazine, and copper ions was developed. The work of this biosensor is based on the principle of change of conductivity of the enzyme membrane when tyrosinase either interacts with 4-chlorophenol substrate or is inhibited by pollutants. The different samples tested were solutions containing diuron, atrazine, copper, lead and zinc ions, mixtures of copper/atrazine or copper/diuron and real water samples coming from a Vietnamese river. In the last case, classical techniques such as GC-MS or atomic absorption spectrometry were used in order to estimate exact concentration of these species in real water samples. Results have shown that such a biosensor could be used as an early warning system for the detection of these pollutants, as no matrix effect coming from the real sample was observed and no synergetic or antagonist effects were found for the mixture of toxic compounds. In addition, results were coherent with the content of the tyrosinase inhibitors

Detection of toxic compounds in real water samples using a conductometric tyrosinase biosensor

Energy Technology Data Exchange (ETDEWEB)

Anh, Tuan Mai [Laboratoire d' Application de la Chimie a l' Environnement, UMR CNRS 5634, Universite Claude Bernard Lyon I, 43 Boulevard du 11 Nov. 1918, 69622 Villeurbanne Cedex (France); International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Vietnam (Viet Nam); Dzyadevych, Sergei V. [Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnogo Str., Kiev 03143 (Ukraine); Prieur, Nicolas [Institute of Natural Products Chemistry, Vietnam National Centre for Science and Technology, Hoang Quoc Viet Str., Hanoi, Vietnam (Viet Nam); Duc, Chien Nguyen [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Vietnam (Viet Nam); Pham, T.D. [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Vietnam (Viet Nam); Renault, Nicole Jaffrezic [Ecole Centrale de Lyon, CEGELY, UMR CNRS 5005, 36 Avenue Guy de Collongue, 69134 Ecully Cedex (France); Chovelon, Jean-Marc [Laboratoire d' Application de la Chimie a l' Environnement, UMR CNRS 5634, Universite Claude Bernard Lyon I, 43 Boulevard du 11 Nov. 1918, 69622 Villeurbanne Cedex (France)]. E-mail: chovelon@univ-lyon1.fr

2006-03-15

A conductometric tyrosinase biosensor for the detection of some toxic compounds including diuron, atrazine, and copper ions was developed. The work of this biosensor is based on the principle of change of conductivity of the enzyme membrane when tyrosinase either interacts with 4-chlorophenol substrate or is inhibited by pollutants. The different samples tested were solutions containing diuron, atrazine, copper, lead and zinc ions, mixtures of copper/atrazine or copper/diuron and real water samples coming from a Vietnamese river. In the last case, classical techniques such as GC-MS or atomic absorption spectrometry were used in order to estimate exact concentration of these species in real water samples. Results have shown that such a biosensor could be used as an early warning system for the detection of these pollutants, as no matrix effect coming from the real sample was observed and no synergetic or antagonist effects were found for the mixture of toxic compounds. In addition, results were coherent with the content of the tyrosinase inhibitors.

The significance of water ionic strength on aluminium toxicity in brown trout (Salmo trutta L.)

Energy Technology Data Exchange (ETDEWEB)

Alstad, Nina E.W. [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Kjelsberg, Birgitte M. [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Voellestad, L. Asbjoern [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Lydersen, Espen [Norwegian Institute for Water Research, P.O. Box 173 Kjelsaas, N-0411 Oslo (Norway); Poleo, Antonio B.S. [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway)]. E-mail: toni.poleo@bio.uio.no

2005-01-01

The toxicity of aluminium to fish is related to interactions between aluminium and the gill surface. We investigated the possible effect of water ionic strength on this interaction. The mortality of brown trout (Salmo trutta L.) exposed to three different degrees of Al polymerisation was compared in water with increased ionic strength (mean 7.31 x 10{sup -4} M) after additions of the base cations Ca{sup 2+}, Mg{sup 2+}, Na{sup +} or K{sup +}, and in water with no such addition (mean ionic strength 5.58 x 10{sup -4} M). Only a very slight ameliorating effect of increased ionic strength was observed, while the degree of Al polymerisation was of major importance in fish mortality. In addition, it was observed that smaller fish survived the Al exposures for a longer time than larger fish. We hypothesise that this is because larger fish are more susceptible to hypoxia than smaller fish. - Ionic strength has a slight ameliorating effect on Al toxicity in brown trout.

The significance of water ionic strength on aluminium toxicity in brown trout (Salmo trutta L.)

International Nuclear Information System (INIS)

Alstad, Nina E.W.; Kjelsberg, Birgitte M.; Voellestad, L. Asbjoern; Lydersen, Espen; Poleo, Antonio B.S.

2005-01-01

The toxicity of aluminium to fish is related to interactions between aluminium and the gill surface. We investigated the possible effect of water ionic strength on this interaction. The mortality of brown trout (Salmo trutta L.) exposed to three different degrees of Al polymerisation was compared in water with increased ionic strength (mean 7.31 x 10 -4 M) after additions of the base cations Ca 2+ , Mg 2+ , Na + or K + , and in water with no such addition (mean ionic strength 5.58 x 10 -4 M). Only a very slight ameliorating effect of increased ionic strength was observed, while the degree of Al polymerisation was of major importance in fish mortality. In addition, it was observed that smaller fish survived the Al exposures for a longer time than larger fish. We hypothesise that this is because larger fish are more susceptible to hypoxia than smaller fish. - Ionic strength has a slight ameliorating effect on Al toxicity in brown trout

Reproductive toxicity of a mixture of regulated drinking-water disinfection by-products in a multigenerational rat bioassay

Science.gov (United States)

BACKGROUND:Trihalomethanes (THMs) and haloaretic acids (HAAs) are regulated disinfection by-products (DBPs); their joint reproductive toxicity in drinking water is unknown.OBJECTIVE: We aimed to evaluate a drinking water mixture of the four regulated THMs and five regulated HAAs ...

Predictive factors of gastroduodenal toxicity in cirrhotic patients after three-dimensional conformal radiotherapy for hepatocellular carcinoma

International Nuclear Information System (INIS)

Kim, Haeyoung; Lim, Do Hoon; Paik, Seung Woon; Yoo, Byung Chul; Koh, Kwang Gheol; Lee, Joon Hyoek; Choi, Moon Seok; Park, Won; Park, Hee Chul; Huh, Seung Jae; Choi, Doo Ho; Ahn, Yong Chan

2009-01-01

Background and purpose: To identify predictive factors for the development of gastroduodenal toxicity (GDT) in cirrhotic patients treated with three-dimensional conformal radiotherapy (3D-CRT) for hepatocellular carcinoma (HCC). Materials and methods: We retrospectively analyzed dose-volume histograms (DVHs) and clinical records of 73 cirrhotic patients treated with 3D-CRT for HCC. The median radiation dose was 36 Gy (range, 30-54 Gy) with a daily dose of 3 Gy. The grade of GDT was defined by the Common Toxicity Criteria Version 2. The predictive factors of grade 3 GDT were identified. Results: Grade 3 GDT was found in 9 patients. Patient's age and the percentage of gastroduodenal volume receiving more than 35 Gy (V 35 ) significantly affected the development of grade 3 GDT. Patients over 50 years of age developed grade 3 GDT more frequently than patients under 50 years of age. The risk of grade 3 GDT grew exponentially as V 35 increased. The 1-year actuarial rate of grade 3 GDT in patients with V 35 35 ≥5% (4% vs. 48%, p 35 were the most predictive factors for the development of grade 3 GDT in patients treated with RT.

Pelletized ponderosa pine bark for adsorption of toxic heavy metals from water

Science.gov (United States)

Miyoung Oh; Mandla A. Tshabalala

2007-01-01

Bark flour from ponderosa pine (Pinus ponderosa) was consolidated into pellets using citric acid as cross-linking agent. The pellets were evaluated for removal of toxic heavy metals from synthetic aqueous solutions. When soaked in water, pellets did not leach tannins, and they showed high adsorption capacity for Cu(ll), Zn(ll), Cd(ll). and Ni(ll) under both equilibrium...

Reproductive toxicity assessment of surface water of the Tai section of the Yangtze River, China by in vitro bioassays coupled with chemical analysis

International Nuclear Information System (INIS)

Wang Xiaoyi; Wu Jiang; Hao Yingqun; Zhu Bingqing; Shi Wei; Hu Guanjiu; Han Xiaodong; Giesy, John P.; Yu Hongxia

2011-01-01

Reproductive toxicity of organic extracts of the surface water from the Tai section of the Yangtze River was assessed by in vitro cytotoxity assays and selected persistent organic pollutants including PCBs, OCPs and PAHs were quantified by instrumental analysis. Eleven of the US EPA priority PAHs were detected. Individual PAHs were found to range from 0.7 to 20 ng/L. Concentrations of BaP did not exceed the national drinking water source quality standard of China. However, a 286-fold concentrated organic extract induced significant reproductive toxicity in adult male rats. The morphology of cells, MTT assay and LDH release assay were all affected by exposure to the organic extracts of water. The results of the reproductive toxicity indicated that PAHs posed the greatest risk of the chemicals studied. The compounds present in the water could be bioconcentrated and result in adverse effects. - Highlights: → Only 11 PAHs of US EPA priority PAHs were detected in surface water the Yangtze River. → Level of BaP didn't exceed national drinking water source quality standard of China. → 286-fold concentrated organic extracts induced great reproductive toxicity in rats. → PAHs posed the greatest risk of the chemicals studied. → The compounds in the water could be bioconcentrated and result in adverse effects. - In vitro bioassay responses observed in Yangtze River source water extracts showed great reproductive toxicity, and PAHs were responsible.

Elucidating mechanisms of toxic action of dissolved organic chemicals in oil sands process-affected water (OSPW).

Science.gov (United States)

Morandi, Garrett D; Wiseman, Steve B; Guan, Miao; Zhang, Xiaowei W; Martin, Jonathan W; Giesy, John P

2017-11-01

Oil sands process-affected water (OSPW) is generated during extraction of bitumen in the surface-mining oil sands industry in Alberta, Canada, and is acutely and chronically toxic to aquatic organisms. It is known that dissolved organic compounds in OSPW are responsible for most toxic effects, but knowledge of the specific mechanism(s) of toxicity, is limited. Using bioassay-based effects-directed analysis, the dissolved organic fraction of OSPW has previously been fractionated, ultimately producing refined samples of dissolved organic chemicals in OSPW, each with distinct chemical profiles. Using the Escherichia coli K-12 strain MG1655 gene reporter live cell array, the present study investigated relationships between toxic potencies of each fraction, expression of genes and characterization of chemicals in each of five acutely toxic and one non-toxic extract of OSPW derived by use of effects-directed analysis. Effects on expressions of genes related to response to oxidative stress, protein stress and DNA damage were indicative of exposure to acutely toxic extracts of OSPW. Additionally, six genes were uniquely responsive to acutely toxic extracts of OSPW. Evidence presented supports a role for sulphur- and nitrogen-containing chemical classes in the toxicity of extracts of OSPW. Copyright © 2017 Elsevier Ltd. All rights reserved.

TOXIC EFFECTS OF CHLOROPICRIN AND IMPACT OF SORBED WATER STEAM ON PROTECTION

Directory of Open Access Journals (Sweden)

Milena Nikolić

2013-01-01

Full Text Available Chloropicrin is a chemical substance that has a very toxic effect. Exerts its effect on the respiratory system. Causes pulmonary edema and difficult breathing and suffocating effect. Respiratory protection may be carried into execution respiratory filters. On the protective power filter based on active coal affects adsorbed water vapor. This paper presents the results of the adsorption of water vapor on activated carbon from 5% to 25%. Was used for the experiment apparatus for dynamic adsorption, the results showed that the humidity of 5% coal provides most power protection, while humidity of 25% minimum protective power.

Comparison of metal toxic impacts between aquatic and terrestrial organisms: is the free ion concentration a sufficient descriptor?

DEFF Research Database (Denmark)

Owsianiak, Mikolaj; Rosenbaum, Ralph K.; Larsen, Henrik Fred

2011-01-01

Characterization of metal toxic impacts in comparative risk assessment and life cycle impact assessment (LCIA) should take into account metal speciation and interactions with soil/water organic constituents, because these mechanisms control metal bioavailability and may influence their toxic...... that the free metal ion is an appropriate “general”descriptor of metal toxicity. Results for 128 laboratory tests on Daphnia magna exposed to copper ions (Cu2+) in water show that variation of several orders of magnitude are observed between the toxicity tests. These variations may be a result of the inability...... of magnitude difference occur for the extreme case of barley (Hordeum vulgare). Given the scarcity of terrestrial effect data compared to aquatic data, reliable and transparent, mechanistic-based predictions of terrestrial toxic impacts from aquatic effect data would be an important step ahead in the context...

Development of biotic ligand models for chronic manganese toxicity to fish, invertebrates, and algae.

Science.gov (United States)

Peters, Adam; Lofts, Stephen; Merrington, Graham; Brown, Bruce; Stubblefield, William; Harlow, Keven

2011-11-01

Ecotoxicity tests were performed with fish, invertebrates, and algae to investigate the effect of water quality parameters on Mn toxicity. Models were developed to describe the effects of Mn as a function of water quality. Calcium (Ca) has a protective effect on Mn toxicity for both fish and invertebrates, and magnesium (Mg) also provides a protective effect for invertebrates. Protons have a protective effect on Mn toxicity to algae. The models derived are consistent with models of the toxicity of other metals to aquatic organisms in that divalent cations can act as competitors to Mn toxicity in fish and invertebrates, and protons act as competitors to Mn toxicity in algae. The selected models are able to predict Mn toxicity to the test organisms to within a factor of 2 in most cases. Under low-pH conditions invertebrates are the most sensitive taxa, and under high-pH conditions algae are most sensitive. The point at which algae become more sensitive than invertebrates depends on the Ca concentration and occurs at higher pH when Ca concentrations are low, because of the sensitivity of invertebrates under these conditions. Dissolved organic carbon concentrations have very little effect on the toxicity of Mn to aquatic organisms. Copyright © 2011 SETAC.

Toxicity alarm: Case history

International Nuclear Information System (INIS)

Hogan, D.; Retallack, J.

1993-01-01

In late fall 1991, the Novacor petrochemical plant near Joffre, Alberta experienced a toxicity alarm, the first since its startup 14 years ago. Fish exposed to a normal toxicity test were stressed within 2 h and showed 100% mortality after 24 h. A history of the events leading up to, during, and after the toxicity alarm is presented. The major effluent sources were three cooling water systems. Although these sources are well characterized, the event causes were not immediately clear. Initial toxic screening indicated that one was very toxic, another moderately toxic, and the third not toxic at all. All three systems utilized the same chemical treatment program to avoid fouling: stabilized phosphates with minor variants. The most toxic of the cooling systems operated at 10-12 cycles, had three chemicals for biocide control, and had three makeup streams. Toxic and nontoxic system characteristics were compared. An in-depth modified toxicity identification and evaluation program was then performed to identify and evaluate the cause of the toxicity alarm for future prevention. The most probable causes of toxicity were identified by elimination. The combination of high numbers of cycles, hydrocarbons in the makeup water, and bromine added as an antifoulant resulted in formation of aromatic bromamines which are capable of causing the toxic condition experienced. 2 tabs

Human Pluripotent Stem Cell-Based Assay Predicts Developmental Toxicity Potential of ToxCast Chemicals (ACT meeting)

Science.gov (United States)

Worldwide initiatives to screen for toxicity potential among the thousands of chemicals currently in use require inexpensive and high-throughput in vitro models to meet their goals. The devTOX quickPredict platform is an in vitro human pluripotent stem cell-based assay used to as...

Plant water potential improves prediction of empirical stomatal models.

Directory of Open Access Journals (Sweden)

William R L Anderegg

Full Text Available Climate change is expected to lead to increases in drought frequency and severity, with deleterious effects on many ecosystems. Stomatal responses to changing environmental conditions form the backbone of all ecosystem models, but are based on empirical relationships and are not well-tested during drought conditions. Here, we use a dataset of 34 woody plant species spanning global forest biomes to examine the effect of leaf water potential on stomatal conductance and test the predictive accuracy of three major stomatal models and a recently proposed model. We find that current leaf-level empirical models have consistent biases of over-prediction of stomatal conductance during dry conditions, particularly at low soil water potentials. Furthermore, the recently proposed stomatal conductance model yields increases in predictive capability compared to current models, and with particular improvement during drought conditions. Our results reveal that including stomatal sensitivity to declining water potential and consequent impairment of plant water transport will improve predictions during drought conditions and show that many biomes contain a diversity of plant stomatal strategies that range from risky to conservative stomatal regulation during water stress. Such improvements in stomatal simulation are greatly needed to help unravel and predict the response of ecosystems to future climate extremes.

Removal of toxic chemicals from water with activated carbon

Science.gov (United States)

Dawson, V.K.; Marking, L.L.; Bills, T.D.

1976-01-01

Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, NoxfishA? (5% rotenone), Dibrorms, juglone, MSa??222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths of 15, 30, and 60 cm; temperatures of 7, 12, 17, and 22 C; pH's of 6.5, 7.5, 8.5, and 9.5; and flow rates of 50, 78, 100, 200, and 940 ml/min. Adsorptive capacity increased when the contact time was increased by reducing the flow rate or increasing the column depth. The adsorptive capacity was not significantly influenced by temperature but was substantially higher at pH 6.5 than at the other pH's tested. A practical and efficient filter for purifying chemically treated water was developed.

Use of zeolite for removing ammonia and ammonia-caused toxicity in marine toxicity identification evaluations.

Science.gov (United States)

Burgess, R M; Perron, M M; Cantwell, M G; Ho, K T; Serbst, J R; Pelletier, M C

2004-11-01

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifying aquatic toxicants. For identifying ammonia toxicity, there are several possible methods including pH alteration and volatilization, Ulva lactuca addition, microbial degradation, and zeolite addition. Zeolite addition has been used successfully in freshwater systems to decrease ammonia concentrations and toxicity for several decades. However, zeolite in marine systems has been used less because ions in the seawater interfere with zeolite's ability to adsorb ammonia. The objective of this study was to develop a zeolite method for removing ammonia from marine waters. To accomplish this objective, we performed a series of zeolite slurry and column chromatography studies to determine uptake rate and capacity and to evaluate the effects of salinity and pH on ammonia removal. We also assessed the interaction of zeolite with several toxic metals. Success of the methods was also evaluated by measuring toxicity to two marine species: the mysid Americamysis bahia and the amphipod Ampelisca abdita. Column chromatography proved to be effective at removing a wide range of ammonia concentrations under several experimental conditions. Conversely, the slurry method was inconsistent and variable in its overall performance in removing ammonia and cannot be recommended. The metals copper, lead, and zinc were removed by zeolite in both the slurry and column treatments. The zeolite column was successful in removing ammonia toxicity for both the mysid and the amphipod, whereas the slurry was less effective. This study demonstrated that zeolite column chromatography is a useful tool for conducting marine water TIEs to decrease ammonia concentrations and characterize toxicity.

Weather and Prey Predict Mammals' Visitation to Water.

Directory of Open Access Journals (Sweden)

Grant Harris

Full Text Available Throughout many arid lands of Africa, Australia and the United States, wildlife agencies provide water year-round for increasing game populations and enhancing biodiversity, despite concerns that water provisioning may favor species more dependent on water, increase predation, and reduce biodiversity. In part, understanding the effects of water provisioning requires identifying why and when animals visit water. Employing this information, by matching water provisioning with use by target species, could assist wildlife management objectives while mitigating unintended consequences of year-round watering regimes. Therefore, we examined if weather variables (maximum temperature, relative humidity [RH], vapor pressure deficit [VPD], long and short-term precipitation and predator-prey relationships (i.e., prey presence predicted water visitation by 9 mammals. We modeled visitation as recorded by trail cameras at Sevilleta National Wildlife Refuge, New Mexico, USA (June 2009 to September 2014 using generalized linear modeling. For 3 native ungulates, elk (Cervus Canadensis, mule deer (Odocoileus hemionus, and pronghorn (Antilocapra americana, less long-term precipitation and higher maximum temperatures increased visitation, including RH for mule deer. Less long-term precipitation and higher VPD increased oryx (Oryx gazella and desert cottontail rabbits (Sylvilagus audubonii visitation. Long-term precipitation, with RH or VPD, predicted visitation for black-tailed jackrabbits (Lepus californicus. Standardized model coefficients demonstrated that the amount of long-term precipitation influenced herbivore visitation most. Weather (especially maximum temperature and prey (cottontails and jackrabbits predicted bobcat (Lynx rufus visitation. Mule deer visitation had the largest influence on coyote (Canis latrans visitation. Puma (Puma concolor visitation was solely predicted by prey visitation (elk, mule deer, oryx. Most ungulate visitation peaked during

Weather and Prey Predict Mammals’ Visitation to Water

Science.gov (United States)

Harris, Grant; Sanderson, James G.; Erz, Jon; Lehnen, Sarah E.; Butler, Matthew J.

2015-01-01

Throughout many arid lands of Africa, Australia and the United States, wildlife agencies provide water year-round for increasing game populations and enhancing biodiversity, despite concerns that water provisioning may favor species more dependent on water, increase predation, and reduce biodiversity. In part, understanding the effects of water provisioning requires identifying why and when animals visit water. Employing this information, by matching water provisioning with use by target species, could assist wildlife management objectives while mitigating unintended consequences of year-round watering regimes. Therefore, we examined if weather variables (maximum temperature, relative humidity [RH], vapor pressure deficit [VPD], long and short-term precipitation) and predator-prey relationships (i.e., prey presence) predicted water visitation by 9 mammals. We modeled visitation as recorded by trail cameras at Sevilleta National Wildlife Refuge, New Mexico, USA (June 2009 to September 2014) using generalized linear modeling. For 3 native ungulates, elk (Cervus Canadensis), mule deer (Odocoileus hemionus), and pronghorn (Antilocapra americana), less long-term precipitation and higher maximum temperatures increased visitation, including RH for mule deer. Less long-term precipitation and higher VPD increased oryx (Oryx gazella) and desert cottontail rabbits (Sylvilagus audubonii) visitation. Long-term precipitation, with RH or VPD, predicted visitation for black-tailed jackrabbits (Lepus californicus). Standardized model coefficients demonstrated that the amount of long-term precipitation influenced herbivore visitation most. Weather (especially maximum temperature) and prey (cottontails and jackrabbits) predicted bobcat (Lynx rufus) visitation. Mule deer visitation had the largest influence on coyote (Canis latrans) visitation. Puma (Puma concolor) visitation was solely predicted by prey visitation (elk, mule deer, oryx). Most ungulate visitation peaked during May and

Comparative toxicity of water soluble fractions of four oils on the growth of a Microalga

Digital Repository Service at National Institute of Oceanography (India)

Phatarpekar, P.V.; Ansari, Z.A.

Toxic effects of water soluble fractions (WSF) of four different fuel oils on a microalga. Tetraselmis gracilis, were examined and compared. On applying different concentrations of WSF, a decrease in cell population was observed. Depending...

The effect of pH on chronic aquatic nickel toxicity is dependent on the pH itself: Extending the chronic nickel bioavailability models.

Science.gov (United States)

Nys, Charlotte; Janssen, Colin R; Van Sprang, Patrick; De Schamphelaere, Karel A C

2016-05-01

The environmental quality standard for Ni in the European Commission's Water Framework Directive is bioavailability based. Although some of the available chronic Ni bioavailability models are validated only for pH ≤ 8.2, a considerable fraction of European surface waters has a pH > 8.2. Therefore, the authors investigated the effect of a change in pH from 8.2 to 8.7 on chronic Ni toxicity in 3 invertebrate (Daphnia magna, Lymnaea stagnalis, and Brachionus calyciflorus) and 2 plant species (Pseudokirchneriella subcapitata and Lemna minor). Nickel toxicity was almost always significantly higher at pH 8.7 than at pH 8.2. To test whether the existing chronic Ni bioavailability models developed for pH ≤ 8.2 can be used at higher pH levels, Ni toxicity at pH 8.7 was predicted based on Ni toxicity observed at pH 8.2. This resulted in a consistent underestimation of toxicity. The results suggest that the effect of pH on Ni(2+) toxicity is dependent on the pH itself: the slope of the pH effect is steeper above than below pH 8.2 for species for which a species-specific bioavailability model exists. Therefore, the existing chronic Ni bioavailability models were modified to allow predictions of chronic Ni toxicity to invertebrates and plants in the pH range of 8.2 to 8.7 by applying a pH slope (SpH ) dependent on the pH of the target water. These modified Ni bioavailability models resulted in more accurate predictions of Ni toxicity to all 5 species (within 2-fold error), without the bias observed using the bioavailability models developed for pH ≤ 8.2. The results of the present study can decrease the uncertainty in implementing the bioavailability-based environmental quality standard under the Water Framework Directive for high-pH regions in Europe. © 2015 SETAC.

Toxicity Estimation Software Tool (TEST)

Science.gov (United States)

The Toxicity Estimation Software Tool (TEST) was developed to allow users to easily estimate the toxicity of chemicals using Quantitative Structure Activity Relationships (QSARs) methodologies. QSARs are mathematical models used to predict measures of toxicity from the physical c...

Blind prediction of interfacial water positions in CAPRI

NARCIS (Netherlands)

Lensink, Marc F; Moal, Iain H; Bates, Paul A; Kastritis, Panagiotis L; Melquiond, Adrien S J; Karaca, Ezgi; Schmitz, Christophe; van Dijk, Marc; Bonvin, Alexandre M J J; Eisenstein, Miriam; Jiménez-García, Brian; Grosdidier, Solène; Solernou, Albert; Pérez-Cano, Laura; Pallara, Chiara; Fernández-Recio, Juan; Xu, Jianqing; Muthu, Pravin; Praneeth Kilambi, Krishna; Gray, Jeffrey J; Grudinin, Sergei; Derevyanko, Georgy; Mitchell, Julie C; Wieting, John; Kanamori, Eiji; Tsuchiya, Yuko; Murakami, Yoichi; Sarmiento, Joy; Standley, Daron M; Shirota, Matsuyuki; Kinoshita, Kengo; Nakamura, Haruki; Chavent, Matthieu; Ritchie, David W; Park, Hahnbeom; Ko, Junsu; Lee, Hasup; Seok, Chaok; Shen, Yang; Kozakov, Dima; Vajda, Sandor; Kundrotas, Petras J; Vakser, Ilya A; Pierce, Brian G; Hwang, Howook; Vreven, Thom; Weng, Zhiping; Buch, Idit; Farkash, Efrat; Wolfson, Haim J; Zacharias, Martin; Qin, Sanbo; Zhou, Huan-Xiang; Huang, Shen-You; Zou, Xiaoqin; Wojdyla, Justyna A; Kleanthous, Colin; Wodak, Shoshana J

We report the first assessment of blind predictions of water positions at protein-protein interfaces, performed as part of the critical assessment of predicted interactions (CAPRI) community-wide experiment. Groups submitting docking predictions for the complex of the DNase domain of colicin E2 and

Organic micropollutants (OMPs) in natural waters: Oxidation by UV/H2O2 treatment and toxicity assessment.

Science.gov (United States)

Rozas, Oscar; Vidal, Cristiane; Baeza, Carolina; Jardim, Wilson F; Rossner, Alfred; Mansilla, Héctor D

2016-07-01

Organic micropollutants (OMPs) are ubiquitous in natural waters even in places where the human activity is limited. The presence of OMPs in natural water sources for human consumption encourages the evaluation of different water purification technologies to ensure water quality. In this study, the Biobío river (Chile) was selected since the watershed includes urban settlements and economic activities (i.e. agriculture, forestry) that incorporate a variety of OMPs into the aquatic environment, such as pesticides, pharmaceuticals and personal care products. Atrazine (herbicide), caffeine (psychotropic), diclofenac (anti-inflammatory) and triclosan (antimicrobial) in Biobío river water and in different stages of a drinking and two wastewater treatment plants downstream Biobío river were determined using solid phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) and electrospray ionization (ESI). Quantification of these four compounds showed concentrations in the range of 8 ± 2 to 55 ± 10 ng L(-1) in Biobío river water, 11 ± 2 to 74 ± 21 ng L(-1) in the drinking water treatment plant, and 60 ± 10 to 15,000 ± 1300 ng L(-1) in the wastewater treatment plants. Caffeine was used as an indicator of wastewater discharges. Because conventional water treatment technologies are not designed to eliminate some emerging organic pollutants, alternative treatment processes, UV and UV/H2O2, were employed. The transformation of atrazine, carbamazepine (antiepileptic), diclofenac and triclosan was investigated at laboratory scale. Both processes were tested at different UV doses and the Biobío river water matrix effects were evaluated. Initial H2O2 concentration used was 10 mg L(-1). Results showed that, the transformation profile obtained using UV/H2O2 at UV doses up to 900 mJ cm(-2), followed the trend of diclofenac > triclosan > atrazine > carbamazepine. Furthermore acute toxicity tests with Daphnia magna were carried

Toxicity of Water Samples Collected in the Vicinity of F and H Seepage Basin 1990-1995

Energy Technology Data Exchange (ETDEWEB)

Specht, W.L. [Westinghouse Savannah River Company, AIKEN, SC (United States); Bowers, B.

1996-09-01

Water and contaminants from the F- and H-Area Seepage Basins outcrop as shallow groundwater seeps down gradient from the basins. In 1990, 1991, 1993, 1994, and 1995, toxicity tests were performed on water collected from a number of these seeps, as well as from several locations in Fourmile Branch and several uncontaminated reference locations.

Rectal toxicity profile after transperineal interstitial permanent prostate brachytherapy: Use of a comprehensive toxicity scoring system and identification of rectal dosimetric toxicity predictors

International Nuclear Information System (INIS)

Shah, Jinesh N.; Ennis, Ronald D.

2006-01-01

Purpose: To better understand rectal toxicity after prostate brachytherapy, we employed the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE version 3.0), a comprehensive system with distinct and separately reported gastrointestinal adverse event items (unlike Radiation Therapy Oncology Group morbidity scoring), to evaluate item-specific postimplant rectal toxicities. Methods and Materials: We analyzed 135 patients treated with brachytherapy ± hormonal therapy, using CTCAE v3.0 to score acute/late rectal toxicities (median follow-up, 41 months). Dosimetric parameters were evaluated for ability to predict toxicities. Results: Use of CTCAE yielded a novel rectal toxicity profile consisting of diarrhea, incontinence, urgency, proctitis, pain, spasms, and hemorrhage event rates. No item had a 25 (percent of rectal volume receiving 25% of prescribed prostate dose) ≤ 25% vs. 60% for %V 25 > 25% (p 1 ≤ 40% vs. 44% for %V 1 > 40% (p = 0.007). Conclusions: A comprehensive understanding of item-specific postimplant rectal toxicities was obtained using CTCAE. Rectal %V 25 > 25% and %V 1 > 40% predicted worse late diarrhea and maximum toxicity, respectively

Identification of developmentally toxic drinking water disinfection byproducts and evaluation of data relevant to mode of action

International Nuclear Information System (INIS)

Colman, Joan; Rice, Glenn E.; Wright, J. Michael; Hunter, E. Sidney; Teuschler, Linda K.; Lipscomb, John C.; Hertzberg, Richard C.; Simmons, Jane Ellen; Fransen, Margaret; Osier, Mark; Narotsky, Michael G.

2011-01-01

Reactions between chemicals used to disinfect drinking water and compounds present in source waters produce chemical mixtures containing hundreds of disinfection byproducts (DBPs). Although the results have been somewhat inconsistent, some epidemiological studies suggest associations may exist between DBP exposures and adverse developmental outcomes. The potencies of individual DBPs in rodent and rabbit developmental bioassays suggest that no individual DBP can account for the relative risk estimates reported in the positive epidemiologic studies, leading to the hypothesis that these outcomes could result from the toxicity of DBP mixtures. As a first step in a mixtures risk assessment for DBP developmental effects, this paper identifies developmentally toxic DBPs and examines data relevant to the mode of action (MOA) for DBP developmental toxicity. We identified 24 developmentally toxic DBPs and four adverse developmental outcomes associated with human DBP exposures: spontaneous abortion, cardiovascular defects, neural tube defects, and low birth weight infancy. A plausible MOA, involving hormonal disruption of pregnancy, is delineated for spontaneous abortion, which some epidemiologic studies associate with total trihalomethane and bromodichloromethane exposures. The DBP data for the other three outcomes were inadequate to define key MOA steps.

A Broad Spectrum Catalytic System for Removal of Toxic Organics from Water by Deep Oxidation - Final Report

Energy Technology Data Exchange (ETDEWEB)

Sen, Ayusman

2000-12-01

A most pressing need for the DOE environmental management program is the removal of toxic organic compounds present in groundwater and soil at specific DOE sites. While several remediation procedures have been proposed, they suffer from one or more drawbacks. The objective of the present research was to develop new catalytic procedures for the removal of toxic organic compounds from the environment through their deep oxidation to harmless products. In water, metallic palladium was found to catalyze the deep oxidation of a wide variety of toxic organic compounds by dioxygen at 80-90 C in the presence of carbon monoxide or dihydrogen. Several classes of organic compounds were examined: benzene, phenol and substituted phenols, nitro and halo organics, organophosphorus, and organosulfur compounds. In every case, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 hour period. For substrates susceptible to hydrogenation, the conversions were generally high with dihydrogen than with carbon monoxide. It is clear from the results obtained that we have discovered an exceptionally versatile catalytic system for the deep oxidation of toxic organic compounds in water. This system possesses several attractive features not found simultaneously in other reported systems. These are (a) the ability to directly utilize dioxygen as the oxidant, (b) the ability to carry out the deep oxidation of a particularly wide range of functional organics, and (c) the ease of recovery of the catalyst by simple filtration.

Clinical Factors Predicting Late Severe Urinary Toxicity After Postoperative Radiotherapy for Prostate Carcinoma: A Single-Institute Analysis of 742 Patients

Energy Technology Data Exchange (ETDEWEB)

Cozzarini, Cesare, E-mail: cozzarini.cesare@hsr.it [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy); Fiorino, Claudio [Department of Medical Physics, San Raffaele Scientific Institute, Milan (Italy); Da Pozzo, Luigi Filippo [Department of Urology, San Raffaele Scientific Institute, Milan (Italy); Alongi, Filippo; Berardi, Genoveffa; Bolognesi, Angelo [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy); Briganti, Alberto [Department of Urology, San Raffaele Scientific Institute, Milan (Italy); Broggi, Sara [Department of Medical Physics, San Raffaele Scientific Institute, Milan (Italy); Deli, Aniko [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy); Guazzoni, Giorgio [Department of Urology, San Raffaele Scientific Institute, Milan (Italy); Perna, Lucia [Department of Medical Physics, San Raffaele Scientific Institute, Milan (Italy); Pasetti, Marcella; Salvadori, Giovannella [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy); Montorsi, Francesco; Rigatti, Patrizio [Department of Urology, San Raffaele Scientific Institute, Milan (Italy); Di Muzio, Nadia [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy)

2012-01-01

Purpose: To investigate the clinical factors independently predictive of long-term severe urinary sequelae after postprostatectomy radiotherapy. Patients and Methods: Between 1993 and 2005, 742 consecutive patients underwent postoperative radiotherapy with either adjuvant (n = 556; median radiation dose, 70.2 Gy) or salvage (n = 186; median radiation dose, 72 Gy) intent. Results: After a median follow-up of 99 months, the 8-year risk of Grade 2 or greater and Grade 3 late urinary toxicity was almost identical (23.9% vs. 23.7% and 12% vs. 10%) in the adjuvant and salvage cohorts, respectively. On univariate analysis, acute toxicity was significantly predictive of late Grade 2 or greater sequelae in both subgroups (p <.0001 in both cases), and hypertension (p = .02) and whole-pelvis radiotherapy (p = .02) correlated significantly in the adjuvant cohort only. The variables predictive of late Grade 3 sequelae were acute Grade 2 or greater toxicity in both groups and whole-pelvis radiotherapy (8-year risk of Grade 3 events, 21% vs. 11%, p = .007), hypertension (8-year risk, 18% vs. 10%, p = .005), age {<=} 62 years at RT (8-year risk, 16% vs. 11%, p = .04) in the adjuvant subset, and radiation dose >72 Gy (8-year risk, 19% vs. 6%, p = .007) and age >71 years (8-year risk, 16% vs. 6%, p = .006) in the salvage subgroup. Multivariate analysis confirmed the independent predictive role of all the covariates indicated as statistically significant on univariate analysis. Conclusions: The risk of late Grade 2 or greater and Grade 3 urinary toxicity was almost identical, regardless of the RT intent. In the salvage cohort, older age and greater radiation doses resulted in a worse toxicity profile, and younger, hypertensive patients experienced a greater rate of severe late sequelae in the adjuvant setting. The causes of this latter correlation and apparently different etiopathogenesis of chronic damage in the two subgroups were unclear and deserve additional investigation.

Fabrication and optimizing of metal nano silicate as toxic metal absorbent from sea water

OpenAIRE

Solgi, Leila

2013-01-01

Pure Water, is a crucial demand of creature life. Following industrial development, extra amount of toxic metals such as chromium enters the environmental cycle through the sewage, which is considered as a serious threat for organisms. One of the modern methods of filtration and removal of contaminants in water, is applying Nano-technology. According to specific property of silicate materials, in this article we try to survey increased power in composites and various absorption in several mor...

A Bayesian network model for predicting aquatic toxicity mode of action using two dimensional theoretical molecular descriptors

Energy Technology Data Exchange (ETDEWEB)

Carriger, John F. [U.S. Environmental Protection Agency, Office of Research and Development, Gulf Ecology Division, Gulf Breeze, FL, 32561 (United States); Martin, Todd M. [U.S. Environmental Protection Agency, Office of Research and Development, Sustainable Technology Division, Cincinnati, OH, 45220 (United States); Barron, Mace G., E-mail: barron.mace@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, Gulf Ecology Division, Gulf Breeze, FL, 32561 (United States)

2016-11-15

Highlights: • A Bayesian network was developed to classify chemical mode of action (MoA). • The network was based on the aquatic toxicity MoA for over 1000 chemicals. • A Markov blanket algorithm selected a subset of theoretical molecular descriptors. • Sensitivity analyses found influential descriptors for classifying the MoAs. • Overall precision of the Bayesian MoA classification model was 80%. - Abstract: The mode of toxic action (MoA) has been recognized as a key determinant of chemical toxicity, but development of predictive MoA classification models in aquatic toxicology has been limited. We developed a Bayesian network model to classify aquatic toxicity MoA using a recently published dataset containing over one thousand chemicals with MoA assignments for aquatic animal toxicity. Two dimensional theoretical chemical descriptors were generated for each chemical using the Toxicity Estimation Software Tool. The model was developed through augmented Markov blanket discovery from the dataset of 1098 chemicals with the MoA broad classifications as a target node. From cross validation, the overall precision for the model was 80.2%. The best precision was for the AChEI MoA (93.5%) where 257 chemicals out of 275 were correctly classified. Model precision was poorest for the reactivity MoA (48.5%) where 48 out of 99 reactive chemicals were correctly classified. Narcosis represented the largest class within the MoA dataset and had a precision and reliability of 80.0%, reflecting the global precision across all of the MoAs. False negatives for narcosis most often fell into electron transport inhibition, neurotoxicity or reactivity MoAs. False negatives for all other MoAs were most often narcosis. A probabilistic sensitivity analysis was undertaken for each MoA to examine the sensitivity to individual and multiple descriptor findings. The results show that the Markov blanket of a structurally complex dataset can simplify analysis and interpretation by

Toxicity challenges in environmental chemicals: Prediction of ...

Science.gov (United States)

Physiologically based pharmacokinetic (PBPK) models bridge the gap between in vitro assays and in vivo effects by accounting for the adsorption, distribution, metabolism, and excretion of xenobiotics, which is especially useful in the assessment of human toxicity. Quantitative structure-activity relationships (QSAR) serve as a vital tool for the high-throughput prediction of chemical-specific PBPK parameters, such as the fraction of a chemical unbound by plasma protein (Fub). The presented work explores the merit of utilizing experimental pharmaceutical Fub data for the construction of a universal QSAR model, in order to compensate for the limited range of high-quality experimental Fub data for environmentally relevant chemicals, such as pollutants, pesticides, and consumer products. Independent QSAR models were constructed with three machine-learning algorithms, k nearest neighbors (kNN), random forest (RF), and support vector machine (SVM) regression, from a large pharmaceutical training set (~1000) and assessed with independent test sets of pharmaceuticals (~200) and environmentally relevant chemicals in the ToxCast program (~400). Small descriptor sets yielded the optimal balance of model complexity and performance, providing insight into the biochemical factors of plasma protein binding, while preventing over fitting to the training set. Overlaps in chemical space between pharmaceutical and environmental compounds were considered through applicability of do

FLUORIDE TOXICITY – A HARSH REALITY

OpenAIRE

Bandlapalli Pavani; Mandava Ragini; David Banji; Otilia J F Banji; N Gouri Pratusha

2011-01-01

There are many incidents of fluoride toxicity whether it is acute or chronic. Fluoride toxicity is an environmental hazard which arises from the upper layers of geological crust and is dissolved in water. Prolonged drinking of such water causes chronic fluoride toxicity. Use of fluoride containing compounds for various purposes such as dental products, metal, glass, refrigerator and chemical industries act as a source of fluoride poisoning and increase the risk of toxicity. This review reflec...

Current and future perspectives on the development, evaluation and application of in silico approaches for predicting toxicity

Science.gov (United States)

Safety-related problems continue to be one of the major reasons of attrition in drug development. Non-testing approaches to predict toxicity could form part of the solution. This review provides a perspective of current status of non-testing approaches available for the predictio...

Study of radon concentration and toxic elements in drinking and irrigated water and its implications in Sungai Petani, Kedah, Malaysia

Directory of Open Access Journals (Sweden)

Nisar Ahmad

2015-07-01

Full Text Available The radon activity concentration and toxic elements have been assessed in drinking and irrigated water samples collected from different locations of Sungai Petani, Kedah, Malaysia. The water samples were collected from wells, streams and taps. A calibrated alpha spectrometer RAD-7 (Model 2890 and Atomic Absorption Spectrometers (Perkin–Elmer, Model AAnalyst 200, Shimadzu, Model AA-700 were used to estimate radon activity concentration and toxic elements, respectively. Maximum average value of radon concentration among the various types of water sources was found 14.7 ± 1.44 Bq/l in well water used for drinking and irrigation and minimum was found 5.37 ± 0.58 Bq/l in tap water used for drinking. Contribution of radon in drinking water to indoor air and age dependent associated annual effective doses were calculated from the measured radon concentration and were found less than lower limit of recommended action level. The activity concentrations of Ni > Pb > Cd > As > Cr were found higher for streams water as compared to wells and tap water. Values of radon concentration in well water were found higher than EPA recommended level and lower than WHO action level while the annual effective doses and level of toxic elements in water reported in this study were found lower than recommended level.

Coastal upwelling linked to toxic Pseudo-nitzschia australis blooms in Los Angeles coastal waters, 2005-2007

KAUST Repository

Schnetzer, Astrid; Jones, Burton; Schaffner, Rebecca A.; Cetinić, Ivona; Fitzpatrick, Elizabeth; Miller, Peter E.; Seubert, Erica L.; Caron, David A.

2013-01-01

Harmful algal blooms dominated by the diatom Pseudo-nitzschia spp. have become a perennial but variable event within surface waters near the greater Los Angeles area. Toxic blooms during spring seasons from 2005 to 2007 varied strongly in their overall toxicity and duration. Differences in bloom dynamics were linked to differences in storm-induced river discharge following episodic rain events and coastal upwelling, both major coastal processes that led to the injection of nutrients into coastal surface waters. Heavy river runoff during early 2005, a record-rainfall year, favored a phytoplankton community mainly comprised of algal taxa other than Pseudo-nitzschia. The spring bloom during 2005 was associated with low domoic acid surface concentrations and minor contributions of (mainly) P. delicatissima to the diatom assemblage. In contrast, highly toxic P. australis-dominated blooms during spring seasons of 2006 and 2007 were linked to strong upwelling events. River discharge quotas in 2006 and 2007, in contrast to 2005, fell well below annual averages for the region. Surface toxin levels were linked to colder, more saline (i.e. upwelled) water over the 3-year study, but no such consistent relationship between domoic acid levels and other physiochemical parameters, such as macronutrient concentrations or nutrient ratios, was observed. © The Author 2013. Published by Oxford University Press. All rights reserved.

Coastal upwelling linked to toxic Pseudo-nitzschia australis blooms in Los Angeles coastal waters, 2005-2007

KAUST Repository

Schnetzer, Astrid

2013-06-10

Harmful algal blooms dominated by the diatom Pseudo-nitzschia spp. have become a perennial but variable event within surface waters near the greater Los Angeles area. Toxic blooms during spring seasons from 2005 to 2007 varied strongly in their overall toxicity and duration. Differences in bloom dynamics were linked to differences in storm-induced river discharge following episodic rain events and coastal upwelling, both major coastal processes that led to the injection of nutrients into coastal surface waters. Heavy river runoff during early 2005, a record-rainfall year, favored a phytoplankton community mainly comprised of algal taxa other than Pseudo-nitzschia. The spring bloom during 2005 was associated with low domoic acid surface concentrations and minor contributions of (mainly) P. delicatissima to the diatom assemblage. In contrast, highly toxic P. australis-dominated blooms during spring seasons of 2006 and 2007 were linked to strong upwelling events. River discharge quotas in 2006 and 2007, in contrast to 2005, fell well below annual averages for the region. Surface toxin levels were linked to colder, more saline (i.e. upwelled) water over the 3-year study, but no such consistent relationship between domoic acid levels and other physiochemical parameters, such as macronutrient concentrations or nutrient ratios, was observed. © The Author 2013. Published by Oxford University Press. All rights reserved.

Predicting water main failures using Bayesian model averaging and survival modelling approach

International Nuclear Information System (INIS)

Kabir, Golam; Tesfamariam, Solomon; Sadiq, Rehan

2015-01-01

To develop an effective preventive or proactive repair and replacement action plan, water utilities often rely on water main failure prediction models. However, in predicting the failure of water mains, uncertainty is inherent regardless of the quality and quantity of data used in the model. To improve the understanding of water main failure, a Bayesian framework is developed for predicting the failure of water mains considering uncertainties. In this study, Bayesian model averaging method (BMA) is presented to identify the influential pipe-dependent and time-dependent covariates considering model uncertainties whereas Bayesian Weibull Proportional Hazard Model (BWPHM) is applied to develop the survival curves and to predict the failure rates of water mains. To accredit the proposed framework, it is implemented to predict the failure of cast iron (CI) and ductile iron (DI) pipes of the water distribution network of the City of Calgary, Alberta, Canada. Results indicate that the predicted 95% uncertainty bounds of the proposed BWPHMs capture effectively the observed breaks for both CI and DI water mains. Moreover, the performance of the proposed BWPHMs are better compare to the Cox-Proportional Hazard Model (Cox-PHM) for considering Weibull distribution for the baseline hazard function and model uncertainties. - Highlights: • Prioritize rehabilitation and replacements (R/R) strategies of water mains. • Consider the uncertainties for the failure prediction. • Improve the prediction capability of the water mains failure models. • Identify the influential and appropriate covariates for different models. • Determine the effects of the covariates on failure

Mitigating with macrophytes: submersed plants reduce the toxicity of pesticide-contaminated water to zooplankton.

Science.gov (United States)

Brogan, William R; Relyea, Rick A

2013-03-01

In ecotoxicology, appreciation is growing for the influence that ecological interactions have on the toxicity of contaminants, such as insecticides, to sensitive species. Most previous studies, however, have focused on factors that exacerbate insecticide effects on species, while factors that may mitigate these effects have been relatively ignored. In aquatic habitats, a small number of studies have shown that submersed macrophytes can remove some insecticides from the water column via sorption. Although examining sorption dynamics is important for understanding the environmental fate of insecticides, whether and to what extent macrophytes actually mitigate insecticide effects on aquatic species remains unknown. In the present study, the authors examined how much and how quickly several realistic densities of the macrophyte Elodea canadensis decreased the toxicity of the insecticide malathion to Daphnia magna, a keystone aquatic herbivore. To do this, the authors quantified Daphnia survival in outdoor test systems (0.95 L) exposed to a factorial combination of five Elodea densities crossed with five malathion concentrations. The authors discovered that malathion's lethality to Daphnia decreased with increasing Elodea density. Furthermore, the rate at which Elodea reduced malathion's toxicity in the water column increased with macrophyte density. These results provide strong evidence that submersed macrophytes can mitigate the ecological impacts of a popular insecticide and further support that ecological interactions can strongly influence contaminant environmental effects. Copyright © 2013 SETAC.

Acute toxicity of pyraclostrobin and trifloxystrobin to Hyalella azteca.

Science.gov (United States)

Morrison, Shane A; McMurry, Scott T; Smith, Loren M; Belden, Jason B

2013-07-01

Fungicide application rates on row crop agriculture have increased across the United States, and subsequently, contamination of adjacent wetlands can occur through spray drift or field runoff. To investigate fungicide toxicity, Hyalella azteca amphipods were exposed to 2 fungicide formulations, Headline and Stratego, and their active strobilurin ingredients, pyraclostrobin and trifloxystrobin. Water-only exposures resulted in similar median lethal concentration (LC50; 20-25 µg/L) values for formulations and strobilurin ingredients, suggesting that toxicity is due to strobilurin ingredients. These values were below concentrations that could occur following spray drift over embedded cropland wetlands. When fungicides were added to overlying water of sediment-water microcosms, toxicity was reduced by 500% for Headline and 160% for Stratego, compared with water-only exposures, based on the total amount of fungicide added to the systems. In addition, when fungicides were added to sediment prior to the addition of water, the reduction in toxicity was even greater, with no toxicity occurring at environmentally relevant levels. Differences in toxicity among exposure groups were explained by dissipation from water as toxicity values based on measured water concentrations were within 20% between all systems. The present study reinforces previous studies that Headline and Stratego are toxic to nontarget aquatic organisms. However, the presence of sediment is likely to ameliorate some toxicity of fungicide formulations, especially if spraying occurs prior to wetland inundation. Copyright © 2013 SETAC.

Assessing the concentrations and risks of toxicity from the antibiotics ciprofloxacin, sulfamethoxazole, trimethoprim and erythromycin in European rivers

International Nuclear Information System (INIS)

Johnson, Andrew C.; Keller, Virginie; Dumont, Egon; Sumpter, John P.

2015-01-01

This study evaluated the potential concentrations of four antibiotics: ciprofloxacin (CIP), sulfamethoxazole (SUF), trimethoprim (TRI) and erythromycin (ERY) throughout the rivers of Europe. This involved reviewing national consumption rates together with assessing excretion and sewage treatment removal rates. From this information, it was possible to construct best, expected and worst case scenarios for the discharge of these antibiotics into rivers. Consumption data showed surprising variations, up to 200-fold in the popularity of different antibiotics across different European nations. Using the water resources model GWAVA which has a spatial resolution of approximately 6 × 9 km, river water concentrations throughout Europe were predicted based on 31-year climate data. The modelled antibiotic concentrations were within the range of measurements reported previously in European effluents and rivers. With the expected scenario, the predicted annual-average antibiotic concentrations ranged between 0 and 10 ng/L for 90% by length of surface waters. In the worst case scenario concentrations could reach between 0.1 and 1 μg/L at the most exposed locations. As both predicted and observed sewage effluent concentrations were below reported effect levels for the most sensitive aquatic wildlife, no direct toxicity in rivers is expected. Predicted river concentrations for CIP and ERY were closest to effect levels in wildlife, followed by SUF which was 2–3 orders of magnitude lower. TRI appeared to be of the least concern with around 6 orders of magnitude difference between predicted and effect levels. However, mixture toxicity may elevate this risk and antibiotic levels of 0.1–1 μg/L in hotspots may contribute to local environmental antibiotic resistance in microorganisms. - Highlights: • Antibiotic consumption varied up to 200-fold between European nations. • Antibiotic concentrations predicted to be 10 ng/L or less for most European rivers. • These antibiotic

Assessing the concentrations and risks of toxicity from the antibiotics ciprofloxacin, sulfamethoxazole, trimethoprim and erythromycin in European rivers

Energy Technology Data Exchange (ETDEWEB)

Johnson, Andrew C., E-mail: ajo@ceh.ac.uk [Centre for Ecology and Hydrology, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Keller, Virginie; Dumont, Egon [Centre for Ecology and Hydrology, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Sumpter, John P. [Institute for the Environment, Brunel University, Uxbridge UB8 (United Kingdom)

2015-04-01

This study evaluated the potential concentrations of four antibiotics: ciprofloxacin (CIP), sulfamethoxazole (SUF), trimethoprim (TRI) and erythromycin (ERY) throughout the rivers of Europe. This involved reviewing national consumption rates together with assessing excretion and sewage treatment removal rates. From this information, it was possible to construct best, expected and worst case scenarios for the discharge of these antibiotics into rivers. Consumption data showed surprising variations, up to 200-fold in the popularity of different antibiotics across different European nations. Using the water resources model GWAVA which has a spatial resolution of approximately 6 × 9 km, river water concentrations throughout Europe were predicted based on 31-year climate data. The modelled antibiotic concentrations were within the range of measurements reported previously in European effluents and rivers. With the expected scenario, the predicted annual-average antibiotic concentrations ranged between 0 and 10 ng/L for 90% by length of surface waters. In the worst case scenario concentrations could reach between 0.1 and 1 μg/L at the most exposed locations. As both predicted and observed sewage effluent concentrations were below reported effect levels for the most sensitive aquatic wildlife, no direct toxicity in rivers is expected. Predicted river concentrations for CIP and ERY were closest to effect levels in wildlife, followed by SUF which was 2–3 orders of magnitude lower. TRI appeared to be of the least concern with around 6 orders of magnitude difference between predicted and effect levels. However, mixture toxicity may elevate this risk and antibiotic levels of 0.1–1 μg/L in hotspots may contribute to local environmental antibiotic resistance in microorganisms. - Highlights: • Antibiotic consumption varied up to 200-fold between European nations. • Antibiotic concentrations predicted to be 10 ng/L or less for most European rivers. • These antibiotic

Acute toxicity and inactivation tests of CO2 on invertebrates in drinking water treatment systems.

Science.gov (United States)

Yin, Wen-Chao; Zhang, Jin-Song; Liu, Li-Jun; Zhao, Jian-Shu; Li, Tuo

2011-01-01

In addition to the esthetic problem caused by invertebrates, researchers are recently starting to be more aware of their potential importance in terms of public health. However, the inactivation methods of invertebrates which could proliferate in drinking water treatment systems are not well developed. The objective of this study is to assess the acute toxicity and inactivation effects of CO2 on familiar invertebrates in water treatment processes. The results of this study revealed that CO2 has a definite toxicity to familiar invertebrates. The values of 24-h LC50 (median lethal concentration) were calculated for each test with six groups of invertebrates. The toxicity of CO2 was higher with increasing concentrations in solution but was lower with the increase in size of the invertebrates. Above the concentration of 1,000 mg/L for the CO2 solution, the 100% inactivation time of all the invertebrates was less than 5 s, and in 15 min, the inactivation ratio showed a gradient descent with a decline in concentration. As seen for Mesocyclops thermocyclopoides, by dosing with a sodium bicarbonate solution first and adding a dilute hydrochloric acid solution 5 min later, it is possible to obtain a satisfactory inactivation effect in the GAC (granular activated carbon) filters.

Comparative analysis of pharmaceuticals versus industrial chemicals acute aquatic toxicity classification according to the United Nations classification system for chemicals. Assessment of the (Q)SAR predictability of pharmaceuticals acute aquatic toxicity and their predominant acute toxic mode-of-action.

Science.gov (United States)

Sanderson, Hans; Thomsen, Marianne

2009-06-01

Pharmaceuticals have been reported to be ubiquitously present in surface waters prompting concerns of effects of these bioactive substances. Meanwhile, there is a general scarcity of publicly available ecotoxicological data concerning pharmaceuticals. The aim of this paper was to compile a comprehensive database based on OECD's standardized measured ecotoxicological data and to evaluate if there is generally cause of greater concern with regards to pharmaceutical aquatic toxicological profiles relative to industrial chemicals. Comparisons were based upon aquatic ecotoxicity classification under the United Nations Global Harmonized System for classification and labeling of chemicals (GHS). Moreover, we statistically explored whether the predominant mode-of-action (MOA) for pharmaceuticals is narcosis. We found 275 pharmaceuticals with 569 acute aquatic effect data; 23 pharmaceuticals had chronic data. Pharmaceuticals were found to be more frequent than industrial chemicals in GHS category III. Acute toxicity was predictable (>92%) using a generic (Q)SAR ((Quantitative) Structure Activity Relationship) suggesting a narcotic MOA. Analysis of model prediction error suggests that 68% of the pharmaceuticals have a non-specific MOA. Additionally, the acute-to-chronic ratio (ACR) for 70% of the analyzed pharmaceuticals was below 25 further suggesting a non-specific MOA. Sub-lethal receptor-mediated effects may however have a more specific MOA.

Development of a Set of Nomograms to Predict Acute Lower Gastrointestinal Toxicity for Prostate Cancer 3D-CRT

International Nuclear Information System (INIS)

Valdagni, Riccardo; Rancati, Tiziana; Fiorino, Claudio; Fellin, Gianni; Magli, Alessandro; Baccolini, Michela; Bianchi, Carla; Cagna, Emanuela; Greco, Carlo; Mauro, Flora A.; Monti, Angelo F.; Munoz, Fernando; Stasi, Michele; Franzone, Paola; Vavassori, Vittorio

2008-01-01

Purpose: To predict acute Radiation Therapy Oncology Group (RTOG)/European Organization for Research and Treatment of Cancer (EORTC) and Subjective Objective Signs Management and Analysis/Late Effect of Normal Tissue (SOMA/LENT) toxicities of the lower gastrointestinal (LGI) syndrome in patients with prostate cancer undergoing three-dimensional conformal radiotherapy using a tool (nomogram) that takes into account clinical and dosimetric variables that proved to be significant in the Italian Association for Radiation Oncology (AIRO) Group on Prostate Cancer (AIROPROS) 0102 trial. Methods and Materials: Acute rectal toxicity was scored in 1,132 patients by using both the RTOG/EORTC scoring system and a 10-item self-assessed questionnaire. Correlation between clinical variables/dose-volume histogram constraints and rectal toxicity was investigated by means of multivariate logistic analyses. Multivariate logistic analyses results were used to create nomograms predicting the symptoms of acute LGI syndrome. Results: Mean rectal dose was a strong predictor of Grade 2-3 RTOG/EORTC acute LGI toxicity (p 0.0004; odds ratio (OR) = 1.035), together with hemorrhoids (p = 0.02; OR 1.51), use of anticoagulants/antiaggregants (p = 0.02; OR = 0.63), and androgen deprivation (AD) (p = 0.04; OR = 0.65). Diabetes (p = 0.34; OR 1.28) and pelvic node irradiation (p = 0.11; OR = 1.56) were significant variables to adjust toxicity prediction. Bleeding was related to hemorrhoids (p = 0.02; OR = 173), AD (p = 0.17; OR = 0.67), and mean rectal dose (p 0.009; OR = 1.024). Stool frequency was related to seminal vesicle irradiation (p = 0.07; OR = 6.46), AD administered for more than 3 months (p = 0.002; OR = 0.32), and the percent volume of rectum receiving more than 60 Gy (V60Gy) V60 (p = 0.02; OR = 1.02). Severe fecal incontinence depended on seminal vesicle irradiation (p = 0.14; OR = 4.5) and V70 (p = 0.033; OR 1.029). Conclusions: To the best of our knowledge, this work presents the

Acute and subchronic toxicity study of the water extract from dried fruits of Piper nigrum L. in rats

Directory of Open Access Journals (Sweden)

Kanjana Jaijoy

2007-03-01

Full Text Available The study was carried out to evaluate acute and subchronic toxicities of the water extract from the dried fruits of Piper nigrum L. A single oral administration of the extract at a dose of 5,000 mg/kg body weight (5 male, 5 female did not produce signs of toxicity, behavioral changes, mortality, changes on gross appearance or histopathological changes of internal organs. The subchronic toxicity was determined by oral feeding both male and female rats (10 male, 10 female daily with the test substance at the doses of 300, 600 and 1,200 mg/kg body weight continuously for 90 days. The examinations of signs, animal behavior and health monitoring showed no abnormalities in the test groups as compared to the controls. The test and control groups (on the 90th day and the satellite group (on the 118th day were analyzed by measuring their final body and organ weights, taking necropsy, and examining hematology, blood clinical chemistry and histopathology. The results suggest that the water extract from the dried fruits of P. nigrum does not cause acute or subchronic toxicities in either male or female rats.

Acute and subchronic toxicity study of the water extract from root of Imperata cylindrica (Linn. Raeusch. in rats

Directory of Open Access Journals (Sweden)

Siharat Chunlaratthanaphorn

2007-03-01

Full Text Available The water extract from root of Imperata cylindrica (Linn. Raeusch. was studied for acute and subchronic toxicities. The extract at a single dose of 5,000 mg/kg was administered orally to female and male rats (5 male, 5 female. After 14 days, signs and behavioral changes, mortality, gross and histopathological changes of internal organs were examined. The extract did not produce signs of toxicity. For the subchronic toxicity test, the extract at doses of 300, 600 and 1,200 mg/kg body weight was orally administered to rats daily for 90 days (10 male, 10 female. The observation of signs, behavior and health status showed no abnormality in the test groups as compared with the controls. At the end of the study, necropsy and histopathology examination were performed in all animals in the control group, the test groups and the satellite group in which the extract was discontinued for another 28 days. Body and organ weights, hematological and blood clinical chemistry were also examined. The results suggest that the water extract of Imperata cylindrica (Linn. Raeusch does not cause acute and subchronic toxicities in rats.

Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of Drinking Water Samples for Toxicity

Science.gov (United States)

2016-03-07

109 | e53555 | Page 1 of 8 Video Article Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of...www.jove.com/ video /53555 DOI: doi:10.3791/53555 Keywords: Environmental Sciences, Issue 109, Fish cells, impedance, sensors, biochip, water toxicity...sensitivity to cholinesterase-inhibiting pesticides . Applications for this toxicity detector are for rapid field-portable testing of drinking water

Can chronic exposure to imidacloprid, clothianidin, and thiamethoxam mixtures exert greater than additive toxicity in Chironomus dilutus?

Science.gov (United States)

Maloney, E M; Morrissey, C A; Headley, J V; Peru, K M; Liber, K

2018-07-30

Widespread agricultural use of neonicotinoid insecticides has resulted in frequent detection of mixtures of these compounds in global surface waters. Recent evidence suggests that neonicotinoid mixtures can elicit synergistic toxicity in aquatic insects under acute exposure conditions, however this has not been validated for longer exposures more commonly encountered in the environment. Therefore, we aimed to characterize the chronic (28-day) toxicity of imidacloprid, clothianidin, and thiamethoxam mixtures under different doses and mixture ratios to determine if the assumption of synergistic toxicity would hold under more environmentally realistic exposure settings. The sensitive aquatic insect Chironomus dilutus was used as a representative test species, and successful emergence was used as a chronic endpoint. Applying the MIXTOX modeling approach, predictive parametric models were fitted using single-compound toxicity data and statistically compared to observed toxicity in subsequent mixture tests. Imidacloprid-clothianidin, clothianidin-thiamethoxam and imidacloprid-clothianidin-thiamethoxam mixtures did not significantly deviate from concentration-additive toxicity. However, the cumulative toxicity of the imidacloprid-thiamethoxam mixture deviated from the concentration-additive reference model, displaying dose-ratio dependent synergism and resulting in up to a 10% greater reduction in emergence from that predicted by concentration addition. Furthermore, exposure to select neonicotinoid mixtures above 1.0 toxic unit tended to shift sex-ratios toward more male-dominated populations. Results indicate that, similar to acute exposures, the general assumption of joint additivity cannot adequately describe chronic cumulative toxicity of all neonicotinoid mixtures. Indeed, our observations of weak synergism and sex-ratio shifts elicited by some mixture combinations should be considered in water quality guideline development and environmental risk assessment practices

Prediction of the bioavailability of potentially toxic elements in freshwaters. Comparison between speciation models and passive samplers.

Science.gov (United States)

Sierra, Jordi; Roig, Neus; Giménez Papiol, Gemma; Pérez-Gallego, Elena; Schuhmacher, Marta

2017-12-15

The aim of this work is to predict the bioavailability of the Potentially Toxic Elements (PTEs) Cd, Pb, Hg, Ni, Cu, Zn, As, Cr and Se in 6 sites within the Ebro River basin. In situ Diffusive gradient in thin-films (DGTs) and classical sampling have been used and compared. The potentially bioavailable fractions of each PTE was estimated by modelling their chemical speciation using three programs (WHAM 7.0, Visual MINTEQ 3.1 and Bio-met), following the suggestions published in recent European regulations. Results of the equilibrium-based models WHAM 7.0 and Visual MINTEQ 3.1 indicate that As, Cd, Ni, Se and Zn, predominate as free metals ions or forming inorganic soluble complexes. Copper, Pb and Hg bioavailability is conditioned by their affinity to dissolved humic substances. According to Visual MINTEQ 3.1, Cr is subjected to redox reactions, being Cr (VI) present (at low concentrations) in the studied rivers. According to Bio-met model, the bioavailability of Cu and Zn is highly influenced by soluble organic matter and water hardness, respectively. For most PTEs, the bioavailability estimated by deploying DGTs in river waters tends to be slightly lower than the estimation obtained with speciation models, since in real conditions more environmental factors take place comparing to the finite number of parameters considered in models. Copyright © 2017 Elsevier B.V. All rights reserved.

Ceriodaphnia dubia as a potential bio-indicator for assessing acute aluminum oxide nanoparticle toxicity in fresh water environment.

Directory of Open Access Journals (Sweden)

Sunandan Pakrashi

Full Text Available Growing nanomaterials based consumer applications have raised concerns about their potential release into the aquatic ecosystems and the consequent toxicological impacts. So environmental monitoring of the nanomaterials in aqueous systems becomes imperative. The current study reveals the potential of Ceriodaphnia dubia (C. dubia as a bio-indicator for aluminum oxide nanoparticles in a fresh water aquatic ecosystem where it occupies an important ecological niche as a primary consumer. This study aims to investigate the aluminium oxide nanoparticle induced acute toxicity on Ceriodaphnia dubia in a freshwater system. The bioavailability of the aluminum oxide nanoparticles has been studied with respect to their aggregation behavior in the system and correlated with the toxicity endpoints. The oxidative stress generated by the particles contributed greatly toward their toxicity. The crucial role of leached aluminium ion mediated toxicity in the later phases (48 h and 72 h in conjunction with the effects from the nano-sized particles in the initial phases (24 h puts forth the dynamics of nanotoxicity in the test system. The internalization of nanoparticles (both gross and systemic uptake as substantiated through the transmission electron microscopy (TEM and inductively coupled plasma optical emission spectral (ICP-OES analysis was another major contributor toward acute toxicity. Concluding the present study, Ceriodaphnia dubia can be a promising candidate for bio-monitoring the aluminium oxide nanoparticles in a fresh water system.

Toxicity of water-soluble fractions of biodiesel fuels derived from castor oil, palm oil, and waste cooking oil.

Science.gov (United States)

Leite, Maria Bernadete Neiva Lemos; de Araújo, Milena Maria Sampaio; Nascimento, Iracema Andrade; da Cruz, Andrea Cristina Santos; Pereira, Solange Andrade; do Nascimento, Núbia Costa

2011-04-01

Concerns over the sustained availability of fossil fuels and their impact on global warming and pollution have led to the search for fuels from renewable sources to address worldwide rising energy demands. Biodiesel is emerging as one of the possible solutions for the transport sector. It shows comparable engine performance to that of conventional diesel fuel, while reducing greenhouse gas emissions. However, the toxicity of products and effluents from the biodiesel industry has not yet been sufficiently investigated. Brazil has a very high potential as a biodiesel producer, in view of its climatic conditions and vast areas for cropland, with consequent environmental risks because of possible accidental biodiesel spillages into water bodies and runoff to coastal areas. This research determined the toxicity to two marine organisms of the water-soluble fractions (WSF) of three different biodiesel fuels obtained by methanol transesterification of castor oil (CO), palm oil (PO), and waste cooking oil (WCO). Microalgae and sea urchins were used as the test organisms, respectively, for culture-growth-inhibition and early-life-stage-toxicity tests. The toxicity levels of the analyzed biodiesel WSF showed the highest toxicity for the CO, followed by WCO and the PO. Methanol was the most prominent contaminant; concentrations increased over time in WSF samples stored up to 120 d. Copyright © 2010 SETAC.

Occurrence of the Microcystins MC-LW and MC-LF in Dutch Surface Waters and Their Contribution to Total Microcystin Toxicity

Directory of Open Access Journals (Sweden)

Elisabeth J. Faassen

2013-07-01

Full Text Available Microcystins (MCs are the most frequently found cyanobacterial toxins in freshwater systems. Many MC variants have been identified and variants differ in their toxicity. Recent studies showed that the variants MC-LW and MC-LF might be more toxic than MC-LR, the variant that is most abundant and mostly used for risk assessments. As little is known about the presence of these two variants in The Netherlands, we determined their occurrence by analyzing 88 water samples and 10 scum samples for eight MC variants ((dm-7-MC-RR, MC-YR, (dm-7-MC-LR, MC-LY, MC-LW and MC-LF by liquid chromatography with tandem mass spectrometry detection. All analyzed MC variants were detected, and MC-LW and/or MC-LF were present in 32% of the MC containing water samples. When MC-LW and MC-LF were present, they contributed to nearly 10% of the total MC concentrations, but due to their suspected high toxicity, their average contribution to the total MC toxicity was estimated to be at least 45%. Given the frequent occurrence and possible high toxicity of MC-LW and MC-LF, it seems better to base health risk assessments on the toxicity contributions of different MC variants than on MC-LR concentrations alone.

The analysis of toxic connections content in water by spectral methods

Science.gov (United States)

Plotnikova, I. V.; Chaikovskaya, O. N.; Sokolova, I. V.; Artyushin, V. R.

2017-08-01

The current state of ecology means the strict observance of measures for the utilization of household and industrial wastes that is connected with very essential expenses of means and time. Thanks to spectroscopic devices usage the spectral methods allow to carry out the express quantitative and qualitative analysis in a workplace and field conditions. In a work the application of spectral methods by studying the degradation of toxic organic compounds after preliminary radiation of various sources is shown. Experimental data of optical density of water at various influences are given.

Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of Drinking Water Samples for Toxicity.

Science.gov (United States)

Brennan, Linda M; Widder, Mark W; McAleer, Michael K; Mayo, Michael W; Greis, Alex P; van der Schalie, William H

2016-03-07

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial (RTgill-W1) cells for use in a field portable water toxicity sensor. A monolayer of RTgill-W1 cells forms on the sensing electrodes enclosed within the biochips. The biochips are then used for testing in a field portable electric cell-substrate impedance sensing (ECIS) device designed for rapid toxicity testing of drinking water. The manuscript further describes how to run a toxicity test using the prepared biochips. A control water sample and the test water sample are mixed with pre-measured powdered media and injected into separate channels of the biochip. Impedance readings from the sensing electrodes in each of the biochip channels are measured and compared by an automated statistical software program. The screen on the ECIS instrument will indicate either "Contamination Detected" or "No Contamination Detected" within an hour of sample injection. Advantages are ease of use and rapid response to a broad spectrum of inorganic and organic chemicals at concentrations that are relevant to human health concerns, as well as the long-term stability of stored biochips in a ready state for testing. Limitations are the requirement for cold storage of the biochips and limited sensitivity to cholinesterase-inhibiting pesticides. Applications for this toxicity detector are for rapid field-portable testing of drinking water supplies by Army Preventative Medicine personnel or for use at municipal water treatment facilities.

Heavy metals, PAHs and toxicity in stormwater wet detention ponds

DEFF Research Database (Denmark)

Wium-Andersen, Tove; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild

2011-01-01

Concentrations of 6 different heavy metals and total Polycyclic Aromatic Hydrocarbons (PAH) were determined in stormwater runoff and in the pond water of two Danish wet detention ponds. The pond water samples were analyzed for toxic effects, using the algae Selenastrum capricornutum as a test...... organism. Stormwater and pond water from a catchment with light industry showed high levels of heavy metals, especially zinc and copper. The pond water showed high toxic effects and copper were found to be the main toxicant. Additionally, a large part of the copper was suspected to be complex bound......, reducing the potential toxicity of the metal. Another catchment (residential) produced stormwater and pond water with moderate concentration of heavy metals. The pond water occasionally showed toxic effects but no correlation between heavy metals and toxicity was identified. PAHs concentrations were...

Comparative Analysis of Predictive Models for Liver Toxicity Using ToxCast Assays and Quantitative Structure-Activity Relationships (MCBIOS)

Science.gov (United States)

Comparative Analysis of Predictive Models for Liver Toxicity Using ToxCast Assays and Quantitative Structure-Activity Relationships Jie Liu1,2, Richard Judson1, Matthew T. Martin1, Huixiao Hong3, Imran Shah1 1National Center for Computational Toxicology (NCCT), US EPA, RTP, NC...

Analyzing the capacity of the Daphnia magna and Pseudokirchneriella subcapitata bioavailability models to predict chronic zinc toxicity at high pH and low calcium concentrations and formulation of a generalized bioavailability model for D. magna.

Science.gov (United States)

Van Regenmortel, Tina; Berteloot, Olivier; Janssen, Colin R; De Schamphelaere, Karel A C

2017-10-01

Risk assessment in the European Union implements Zn bioavailability models to derive predicted-no-effect concentrations for Zn. These models are validated within certain boundaries (i.e., pH ≤ 8 and Ca concentrations ≥ 5mg/L), but a substantial fraction of the European surface waters falls outside these boundaries. Therefore, we evaluated whether the chronic Zn biotic ligand model (BLM) for Daphnia magna and the chronic bioavailability model for Pseudokirchneriella subcapitata could be extrapolated to pH > 8 and Ca concentrations model can accurately predict Zn toxicity for Ca concentrations down to 0.8 mg/L and pH values up to 8.5. Because the chronic Zn BLM for D. magna could not be extrapolated beyond its validity boundaries for pH, a generalized bioavailability model (gBAM) was developed. Of 4 gBAMs developed, we recommend the use of gBAM-D, which combines a log-linear relation between the 21-d median effective concentrations (expressed as free Zn 2+ ion activity) and pH, with more conventional BLM-type competition constants for Na, Ca, and Mg. This model is a first step in further improving the accuracy of chronic toxicity predictions of Zn as a function of water chemistry, which can decrease the uncertainty in implementing the bioavailability-based predicted-no-effect concentration in the risk assessment of high-pH and low-Ca concentration regions in Europe. Environ Toxicol Chem 2017;36:2781-2798. © 2017 SETAC. © 2017 SETAC.

Occurrence of estrogenic activities in second-grade surface water and ground water in the Yangtze River Delta, China

International Nuclear Information System (INIS)

Shi, Wei; Hu, Guanjiu; Chen, Sulan; Wei, Si; Cai, Xi; Chen, Bo; Feng, Jianfang; Hu, Xinxin; Wang, Xinru; Yu, Hongxia

2013-01-01

Second-grade surface water and ground water are considered as the commonly used cleanest water in the Yangtze River Delta, which supplies centralized drinking water and contains rare species. However, some synthetic chemicals with estrogenic disrupting activities are detectable. Estrogenic activities in the second-grade surface water and ground water were surveyed by a green monkey kidney fibroblast (CV-1) cell line based ER reporter gene assay. Qualitative and quantitative analysis were further conducted to identify the responsible compounds. Estrogen receptor (ER) agonist activities were present in 7 out of 16 surface water and all the ground water samples. Huaihe River and Yangtze River posed the highest toxicity potential. The highest equivalent (2.2 ng E 2 /L) is higher than the predicted no-effect-concentration (PNEC). Bisphenol A (BPA) contributes to greater than 50% of the total derived equivalents in surface water, and the risk potential in this region deserves more attention and further research. -- Highlights: •Estrogenic activities were present in second-grade surface water and ground water. •Most of the detected equivalents were higher than the predicted no-effect-concentration of E 2 . •ER-EQ 20–80 ranges showed that samples in Huaihe River and Yangtze River posed the highest toxicity. •Bisphenol A contributes to most of the instrumentally derived equivalents in surface water. -- Estrogenic activities were observed in second-grade surface water and ground water in Yangtze River Delta, and BPA was the responsible contaminant

Anaerobic biodegradability and toxicity of complex or toxicant wastewater

International Nuclear Information System (INIS)

Wills Betancur, B.A.

1995-01-01

As a first approximation to wastewater classification in susceptibility terms to treatment by anaerobic biological system, anaerobic biodegradability trials are accomplished to leached of sanitary landfill, to wastewater of coffee grain wet treatment plant and to wastewater of fumaric acid recuperation plant. In the last Plant, anaerobic toxicity trials and lethal toxicity on the Daphnia pulex micro-crustacean are made too. Anaerobic biological trials are made continuing the Wageningen University (Holland) Methodology (1.987). Lethal toxicity biological trials are made following the Standard Methods for the Examination of Water and Wastewater(18th edition, 1992). In development of this investigation project is found that fumaric acid recuperation plant leached it has a low anaerobic biodegradability, a high anaerobic toxicity and a high lethal toxicity over Daphnia pulex, for such reasons this leached is cataloged as complex and toxic wastewater. The other hand, wastewater of coffee grain wet treatment plant and wastewater of sanitary landfill they are both highly biodegradability and not-toxic, for such reasons these wastewaters are cataloged as susceptible to treatment by anaerobic biological system

Determination of water quality, toxicity and estrogenic activity in a nearshore marine environment in Rio de Janeiro, Southeastern Brazil.

Science.gov (United States)

do Nascimento, Marilia Teresa Lima; Santos, Ana Dalva de Oliveira; Felix, Louise Cruz; Gomes, Giselle; de Oliveira E Sá, Mariana; da Cunha, Danieli Lima; Vieira, Natividade; Hauser-Davis, Rachel Ann; Baptista Neto, José Antonio; Bila, Daniele Maia

2018-03-01

Endocrine disrupting compounds (EDCs) can be found in domestic sewage, wastewater treatment plant effluents, natural water, rivers, lakes and in the marine environment. Jurujuba Sound, located in the state of Rio de Janeiro, Southeastern Brazil, receives untreated sewage into its waters, one the main sources of aquatic contamination in this area. In this context, the aim of the present study was to evaluate the estrogenic potential of water sampled from different depths and from areas with differential contamination levels throughout Jurujuba Sound. Water quality was evaluated and acute toxicity assays using Allviibrio fischeri were conducted, while estrogenic activity of the water samples was determined by a Yeast Estrogen Screening assay (YES). Water quality was mostly within the limits established for marine waters by the Brazilian legislation, with only DOC and ammoniacal nitrogen levels above the maximum permissible limits. No acute toxicity effects were observed in the Allivibrio fisheri assay. The YES assay detected moderate estrogenic activity in bottom water samples from 3 sampling stations, ranging from 0.5 to 3.2ngL -1 , as well as in one surface water sample. Estrogenic activity was most frequently observed in samples from the bottom of the water column, indicating adsorption of estrogenic compounds to the sediment. Copyright © 2017 Elsevier Inc. All rights reserved.

Water Habitat Study: Prediction Makes It More Meaningful.

Science.gov (United States)

Glasgow, Dennis R.

1982-01-01

Suggests a teaching strategy for water habitat studies to help students make a meaningful connection between physiochemical data (dissolved oxygen content, pH, and water temperature) and biological specimens they collect. Involves constructing a poster and using it to make predictions. Provides sample poster. (DC)

Application of reverse osmosis membrane for separation of toxic metal in water

International Nuclear Information System (INIS)

Syahril Ahmad

2010-01-01

Experimental separation of toxic metal in water has been done using reverse osmosis membrane made from composite material. Experiment was done by simulation in which metals that will be observed solved with water in different concentration and then used as feed solution in reverse osmosis process. Metals observed were Cr"6"+, Mn"2"+ and Pb"2"+ and reverse osmosis process was done at pressure of 40 Bar for all metals. Experiment result showed that value of feed solution concentration would affect flux and coefficient rejection of membrane. Composite membrane with polyacrylamide as active layer of membrane can reject metals observed with value of rejection coefficient more than 90%, except for Mn"2"+metal that have concentration 250 ppm and 500 ppm. (author)

Identification of water soluble and particle bound compounds causing sublethal toxic effects. A field study on sediments affected by a chlor-alkali industry

International Nuclear Information System (INIS)

Bosch, Carme; Olivares, Alba; Faria, Melissa; Navas, Jose M.; Olmo, Ivan del; Grimalt, Joan O.; Pina, Benjamin; Barata, Carlos

2009-01-01

A combination of cost effective sublethal Daphnia magna feeding tests, yeast- and cell culture-based bioassays and Toxicity Identification Evaluation (TIE) procedures was used to characterize toxic compounds within sediments collected in a river area under the influence of the effluents from a chlor-alkali industry (Ebro River, NE Spain). Tests were designed to measure and identify toxic compounds in the particulate and filtered water fractions of sediment elutriates. The combined use of bioassays responding to elutriates and dioxin-like compounds evidenced the existence of three major groups of hazardous contaminants in the most contaminated site: (A) metals such as cadmium and mercury bound to sediment fine particles that could be easily resuspended and moved downstream, (B) soluble compounds (presumably, lye) able to alkalinize water to toxic levels, and (C) organochlorine compounds with high dioxin-like activity. These results provided evidence that elutriate D. magna feeding responses can be used as surrogate assays for more tedious chronic whole sediment tests, and that the incorporation of such tests in sediment TIE procedures may improve the ability to identify the toxicity of particle-bound and water-soluble contaminants in sediments.

A Novel Method for Predicting Late Genitourinary Toxicity After Prostate Radiation Therapy and the Need for Age-Based Risk-Adapted Dose Constraints

International Nuclear Information System (INIS)

Ahmed, Awad A.; Egleston, Brian; Alcantara, Pino; Li, Linna; Pollack, Alan; Horwitz, Eric M.; Buyyounouski, Mark K.

2013-01-01

Background: There are no well-established normal tissue sparing dose–volume histogram (DVH) criteria that limit the risk of urinary toxicity from prostate radiation therapy (RT). The aim of this study was to determine which criteria predict late toxicity among various DVH parameters when contouring the entire solid bladder and its contents versus the bladder wall. The area under the histogram curve (AUHC) was also analyzed. Methods and Materials: From 1993 to 2000, 503 men with prostate cancer received 3-dimensional conformal RT (median follow-up time, 71 months). The whole bladder and the bladder wall were contoured in all patients. The primary endpoint was grade ≥2 genitourinary (GU) toxicity occurring ≥3 months after completion of RT. Cox regressions of time to grade ≥2 toxicity were estimated separately for the entire bladder and bladder wall. Concordance probability estimates (CPE) assessed model discriminative ability. Before training the models, an external random test group of 100 men was set aside for testing. Separate analyses were performed based on the mean age (≤ 68 vs >68 years). Results: Age, pretreatment urinary symptoms, mean dose (entire bladder and bladder wall), and AUHC (entire bladder and bladder wall) were significant (P 68 years. Conclusion: The AUHC method based on bladder wall volumes was superior for predicting late GU toxicity. Age >68 years was associated with late grade ≥2 GU toxicity, which suggests that risk-adapted dose constraints based on age should be explored

Toxicity of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin to photoautotrophic aquatic organisms.

Science.gov (United States)

Ebert, Ina; Bachmann, Jean; Kühnen, Ute; Küster, Anette; Kussatz, Carola; Maletzki, Dirk; Schlüter, Christoph

2011-12-01

The present study investigated the growth inhibition effect of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin on four photoautotrophic aquatic species: the freshwater microalga Desmodesmus subspicatus, the cyanobacterium Anabaena flos-aquae, the monocotyledonous macrophyte Lemna minor, and the dicotyledonous macrophyte Myriophyllum spicatum. Both antibiotics, which act by inhibiting the bacterial DNA gyrase, demonstrated high toxicity to A. flos-aquae and L. minor and moderate to slight toxicity to D. subspicatus and M. spicatum. The cyanobacterium was the most sensitive species with median effective concentration (EC50) values of 173 and 10.2 µg/L for enrofloxacin and ciprofloxacin, respectively. Lemna minor proved to be similarly sensitive, with EC50 values of 107 and 62.5 µg/L for enrofloxacin and ciprofloxacin, respectively. While enrofloxacin was more toxic to green algae, ciprofloxacin was more toxic to cyanobacteria. Calculated EC50s for D. subspicatus were 5,568 µg/L and >8,042 µg/L for enrofloxacin and ciprofloxacin, respectively. These data, as well as effect data from the literature, were compared with predicted and reported environmental concentrations. For two of the four species, a risk was identified at ciprofloxacin concentrations found in surface waters, sewage treatment plant influents and effluents, as well as in hospital effluents. For ciprofloxacin the results of the present study indicate a risk even at the predicted environmental concentration. In contrast, for enrofloxacin no risk was identified at predicted and measured concentrations. Copyright © 2011 SETAC.

Assessing the toxic effects of ethylene glycol ethers using Quantitative Structure Toxicity Relationship models

International Nuclear Information System (INIS)

Ruiz, Patricia; Mumtaz, Moiz; Gombar, Vijay

2011-01-01

Experimental determination of toxicity profiles consumes a great deal of time, money, and other resources. Consequently, businesses, societies, and regulators strive for reliable alternatives such as Quantitative Structure Toxicity Relationship (QSTR) models to fill gaps in toxicity profiles of compounds of concern to human health. The use of glycol ethers and their health effects have recently attracted the attention of international organizations such as the World Health Organization (WHO). The board members of Concise International Chemical Assessment Documents (CICAD) recently identified inadequate testing as well as gaps in toxicity profiles of ethylene glycol mono-n-alkyl ethers (EGEs). The CICAD board requested the ATSDR Computational Toxicology and Methods Development Laboratory to conduct QSTR assessments of certain specific toxicity endpoints for these chemicals. In order to evaluate the potential health effects of EGEs, CICAD proposed a critical QSTR analysis of the mutagenicity, carcinogenicity, and developmental effects of EGEs and other selected chemicals. We report here results of the application of QSTRs to assess rodent carcinogenicity, mutagenicity, and developmental toxicity of four EGEs: 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, and 2-butoxyethanol and their metabolites. Neither mutagenicity nor carcinogenicity is indicated for the parent compounds, but these compounds are predicted to be developmental toxicants. The predicted toxicity effects were subjected to reverse QSTR (rQSTR) analysis to identify structural attributes that may be the main drivers of the developmental toxicity potential of these compounds.

Geospatial application of the Water Erosion Prediction Project (WEPP) Model

Science.gov (United States)

D. C. Flanagan; J. R. Frankenberger; T. A. Cochrane; C. S. Renschler; W. J. Elliot

2011-01-01

The Water Erosion Prediction Project (WEPP) model is a process-based technology for prediction of soil erosion by water at hillslope profile, field, and small watershed scales. In particular, WEPP utilizes observed or generated daily climate inputs to drive the surface hydrology processes (infiltration, runoff, ET) component, which subsequently impacts the rest of the...

Toxicity evaluation of boron nitride nanospheres and water-soluble boron nitride in Caenorhabditis elegans.

Science.gov (United States)

Wang, Ning; Wang, Hui; Tang, Chengchun; Lei, Shijun; Shen, Wanqing; Wang, Cong; Wang, Guobin; Wang, Zheng; Wang, Lin

2017-01-01

Boron nitride (BN) nanomaterials have been increasingly explored for potential biological applications. However, their toxicity remains poorly understood. Using Caenorhabditis elegans as a whole-animal model for toxicity analysis of two representative types of BN nanomaterials - BN nanospheres (BNNSs) and highly water-soluble BN nanomaterial (named BN-800-2) - we found that BNNSs overall toxicity was less than soluble BN-800-2 with irregular shapes. The concentration thresholds for BNNSs and BN-800-2 were 100 µg·mL -1 and 10 µg·mL -1 , respectively. Above this concentration, both delayed growth, decreased life span, reduced progeny, retarded locomotion behavior, and changed the expression of phenotype-related genes to various extents. BNNSs and BN-800-2 increased oxidative stress levels in C. elegans by promoting reactive oxygen species production. Our results further showed that oxidative stress response and MAPK signaling-related genes, such as GAS1 , SOD2 , SOD3 , MEK1 , and PMK1 , might be key factors for reactive oxygen species production and toxic responses to BNNSs and BN-800-2 exposure. Together, our results suggest that when concentrations are lower than 10 µg·mL -1 , BNNSs are more biocompatible than BN-800-2 and are potentially biocompatible material.

Capture of toxic radioactive and heavy metal ions from water by using titanate nanofibers

Energy Technology Data Exchange (ETDEWEB)

Xu, Jiasheng, E-mail: jiashengxu@bhu.edu.cn [Liaoning Province Key Laboratory for Synthesis and Application of Functional Compounds, College of Chemistry, Chemical Engineering and Food Safety, Center of Science and Technology Experiment, Bohai University, 19 Sci-tech Road, Jinzhou 121013 (China); Zhang, He; Zhang, Jie [Liaoning Province Key Laboratory for Synthesis and Application of Functional Compounds, College of Chemistry, Chemical Engineering and Food Safety, Center of Science and Technology Experiment, Bohai University, 19 Sci-tech Road, Jinzhou 121013 (China); Kim, Eui Jung [School of Chemical Engineering and Bioengineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

2014-11-25

Highlights: • Three types of titanate nanofibers were prepared via a hydrothermal porcess. • These nanofibers show availability for removal of the toxic ions from water. • The equilibrium data were fitted well with the Langmuir model. - Abstract: Three types of titanate nanofibers (sodium titanate nanofibers (TNF-A), potassium/sodium titanate nanofibers (TNF-B), potassium titanate nanofibers (TNF-C)) were prepared via a hydrothermal treatment of anatase powders in different alkali solutions at 170 °C for 96 h, respectively. The as-prepared nanofibers have large specific surface area and show availability for the removal of radioactive and heavy metal ions from water system, such as Ba{sup 2+} (as substitute of {sup 226}Ra{sup 2+}) and Pb{sup 2+} ions. The TNF-A shows a better capacity in the removal of Ba{sup 2+} and Pb{sup 2+} than TNF-B and TNF-C. Structural characterization of the materials was performed with powder X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and with inductively coupled plasma optical emission spectrometry (ICP-OES). It is found that the equilibrium data fit well with the Langmuir model. This study highlights that nanoparticles of inorganic ion exchangers with layered structure are potential materials for efficient removal of the toxic ions from contaminated water.

Hierarchical prediction of industrial water demand based on refined Laspeyres decomposition analysis.

Science.gov (United States)

Shang, Yizi; Lu, Shibao; Gong, Jiaguo; Shang, Ling; Li, Xiaofei; Wei, Yongping; Shi, Hongwang

2017-12-01

A recent study decomposed the changes in industrial water use into three hierarchies (output, technology, and structure) using a refined Laspeyres decomposition model, and found monotonous and exclusive trends in the output and technology hierarchies. Based on that research, this study proposes a hierarchical prediction approach to forecast future industrial water demand. Three water demand scenarios (high, medium, and low) were then established based on potential future industrial structural adjustments, and used to predict water demand for the structural hierarchy. The predictive results of this approach were compared with results from a grey prediction model (GPM (1, 1)). The comparison shows that the results of the two approaches were basically identical, differing by less than 10%. Taking Tianjin, China, as a case, and using data from 2003-2012, this study predicts that industrial water demand will continuously increase, reaching 580 million m 3 , 776.4 million m 3 , and approximately 1.09 billion m 3 by the years 2015, 2020 and 2025 respectively. It is concluded that Tianjin will soon face another water crisis if no immediate measures are taken. This study recommends that Tianjin adjust its industrial structure with water savings as the main objective, and actively seek new sources of water to increase its supply.

Rapid and accurate prediction and scoring of water molecules in protein binding sites.

Directory of Open Access Journals (Sweden)

Gregory A Ross

Full Text Available Water plays a critical role in ligand-protein interactions. However, it is still challenging to predict accurately not only where water molecules prefer to bind, but also which of those water molecules might be displaceable. The latter is often seen as a route to optimizing affinity of potential drug candidates. Using a protocol we call WaterDock, we show that the freely available AutoDock Vina tool can be used to predict accurately the binding sites of water molecules. WaterDock was validated using data from X-ray crystallography, neutron diffraction and molecular dynamics simulations and correctly predicted 97% of the water molecules in the test set. In addition, we combined data-mining, heuristic and machine learning techniques to develop probabilistic water molecule classifiers. When applied to WaterDock predictions in the Astex Diverse Set of protein ligand complexes, we could identify whether a water molecule was conserved or displaced to an accuracy of 75%. A second model predicted whether water molecules were displaced by polar groups or by non-polar groups to an accuracy of 80%. These results should prove useful for anyone wishing to undertake rational design of new compounds where the displacement of water molecules is being considered as a route to improved affinity.

Solubility of water in fluorocarbons: Experimental and COSMO-RS prediction results

International Nuclear Information System (INIS)

Freire, Mara G.; Carvalho, Pedro J.; Santos, Luis M.N.B.F.; Gomes, Ligia R.; Marrucho, Isabel M.; Coutinho, Joao A.P.

2010-01-01

This work aims at providing experimental and theoretical information about the water-perfluorocarbon molecular interactions. For that purpose, experimental solubility results for water in cyclic and aromatic perfluorocarbons (PFCs), over the temperature range between (288.15 and 318.15) K, and at atmospheric pressure, were obtained and are presented. From the experimental solubility dependence on temperature, the partial molar solution and solvation thermodynamic functions such as Gibbs free energy, enthalpy and entropy were determined and are discussed. The process of dissolution of water in PFCs is shown to be spontaneous for cyclic and aromatic compounds. It is demonstrated that the interactions between the non-aromatic PFCs and water are negligible while those between aromatic PFCs and water are favourable. The COSMO-RS predictive capability was explored for the description of the water solubility in PFCs and others substituted fluorocompounds. The COSMO-RS is shown to be a useful model to provide reasonable predictions of the solubility values, as well as to describe their temperature and structural modifications dependence. Moreover, the molar Gibbs free energy and molar enthalpy of solution of water are predicted remarkably well by COSMO-RS while the main deviations appear for the prediction of the molar entropy of solution.

Toxicity of effluents from gasoline stations oil-water separators to early life stages of zebrafish Danio rerio.

Science.gov (United States)

Alves, Romulo Nepomuceno; Mariz, Célio Freire; Paulo, Driele Ventura de; Carvalho, Paulo S M

2017-07-01

Used petroleum hydrocarbons and gasoline stations runoff are significant sources of polycyclic aromatic hydrocarbons (PAHs) to aquatic ecosystems. Samples of the final effluent of oil-water-separators were collected at gasoline stations in the metropolitan region of Recife, Brazil, before release to sewage or rainwater systems. Effluent soluble fractions (ESF) were prepared and bioassays were performed according to the Fish Embryo Toxicity Test. The test involved exposing zebrafish Danio rerio embryos to dilutions of the ESFs for 96 h, with daily examination of lethality and sublethal morphological effects integrated through the General Morphology Score (GMS), based on the achievement of developmental hallmarks. Frequencies of abnormalities were recorded after exposures. ESF LC50-96h (lethal concentration to 50% of exposed embryos) in the most toxic effluent achieved 8.9% (v/v), equivalent to 11 μg phenanthrene equivalents L -1 . GMS scores indicated significantly delayed embryo-larval development at ESF dilutions of 10% and 20% from effluents of all gas stations. Major abnormalities detected after the 96 h exposure included the presence of a yolk sac not fully absorbed coupled with the lack of an inflated swim bladder, lack of both pectoral fins, and the failure to develop a protruding mouth. Effective equivalent PAH concentrations that induce a 50% frequency of larvae without an inflated swim bladder (EC50) were 4.9 μg phenanthrene L -1 , 21.8 μg naphthalene L -1 , and 34.1 μg chrysene L -1 . This study shows that PAHs in ESFs from gas stations oil water separators are toxic to zebrafish, contributing to the toxicity of urban storm waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-throughput sequencing reveals microbial communities in drinking water treatment sludge from six geographically distributed plants, including potentially toxic cyanobacteria and pathogens.

Science.gov (United States)

Xu, Hangzhou; Pei, Haiyan; Jin, Yan; Ma, Chunxia; Wang, Yuting; Sun, Jiongming; Li, Hongmin

2018-04-10

The microbial community structures of drinking water treatment sludge (DWTS) generated for raw water (RW) from different locations and with different source types - including river water, lake water and reservoir water -were investigated using high-throughput sequencing. Because the unit operations in the six DWTPs were similar, community composition in fresh sludge may be determined by microbial community in the corresponding RW. Although Proteobacteria, Cyanobacteria, Bacteroidetes, Firmicutes, Verrucomicrobia, and Planctomycetes were the dominant phyla among the six DWTS samples, no single phylum exhibited similar abundance across all the samples, owing to differences in total phosphorus, chemical oxygen demand, Al, Fe, and chloride in RW. Three genera of potentially toxic cyanobacteria (Planktothrix, Microcystis and Cylindrospermopsis), and four potential pathogens (Escherichia coli, Bacteroides ovatus, Prevotella copri and Rickettsia) were found in sludge samples. Because proliferation of potentially toxic cyanobacteria and Rickettsia in RW was mainly affected by nutrients, while growth of Escherichia coli, Bacteroides ovatus and Prevotella copri in RW may be influenced by Fe, control of nutrients and Fe in RW is essential to decrease toxic cyanobacteria and pathogens in DWTS. Copyright © 2018 Elsevier B.V. All rights reserved.

Investigation of Water Safety in Non-treated Drinking Water with Trace Toxic Metals.

Science.gov (United States)

Ly, Suw Young; Kim, Dae Hong; Lee, Ga Eun

2013-09-01

The trace toxic metal copper was assayed using mercury immobilized on a carbon nanotube electrode (MCW), with a graphite counter and a reference electrode. In this study, a macro-scale convection motor was interfaced with a MCW three-electrode system, in which a handmade MCW was optimized using cyclic- and square-wave stripping voltammetry. An analytical electrolyte for tap water was used instead of an expensive acid or base ionic solution. Under these conditions, optimum parameters were 0.09 V amplitude, 40 Hz frequency, 0.01 V incremental potential, and a 60-s accumulation time. A diagnostic working curve was obtained from 50.0 to 350 μg/L. At a constant Cu(II) concentration of 10.0 μg/L, the statistical relative standard deviation was 1.78% (RSD, n = 15), the analytical accumulation time was only 60 s, and the analytical detection limit approached 4.6 μg/L (signal/noise = 3). The results were applied to nontreated drinking water. The content of the analyzed copper using 9.0 and 4.0 μg/L standards were 8.68 μg/L and 3.96 μg/L; statistical values R(2) = 0.9987 and R(2) = 0.9534, respectively. This method is applicable to biological diagnostics or food surveys.

A Novel Two-Step Hierarchial Quantitative Structure-Activity Relationship Modeling Workflow for Predicting Acute Toxicity of Chemicals in Rodents

Science.gov (United States)

Background: Accurate prediction of in vivo toxicity from in vitro testing is a challenging problem. Large public–private consortia have been formed with the goal of improving chemical safety assessment by the means of high-throughput screening. Methods and results: A database co...

Metal and pharmaceutical mixtures: Is ion loss the mechanism underlying acute toxicity and widespread additive toxicity in zebrafish?

Energy Technology Data Exchange (ETDEWEB)

Alsop, Derek, E-mail: alsopde@mcmaster.ca; Wood, Chris M.

2013-09-15

Highlights: •Zebrafish larvae were used to test the acute toxicity of contaminant mixtures. •Interactions were observed between metals, ammonia and pharmaceuticals. •Larval Na{sup +} loss was observed with exposure to all acutely toxic contaminants tested. •Water quality criteria should recognize the toxic interactions between contaminants. -- Abstract: The acute toxicities and mechanisms of action of a variety of environmental contaminants were examined using zebrafish larvae (Danio rerio; 4–8 days post fertilization). Toxic interactions were observed between metals. For example, the addition of a sublethal level of nickel (15% of the LC{sub 50}, one third of the LC{sub 01}) to all copper treatments decreased the copper 96 h LC{sub 50} by 58%, while sublethal copper exposure (6% of the copper LC{sub 50}, 13% of the LC{sub 01}) decreased the cadmium 96 h LC{sub 50} by 47%. Two predictive models were assessed, the concentration addition (CA) model, which assumes similar mechanisms of action, and the independent action (IA) model, which assumes different mechanisms of action. Quantitative comparisons indicated the CA model performed better than the IA model; the latter tended to underestimate combined toxicity to a greater extent. The effects of mixtures with nickel or ammonia were typically additive, while mixtures with copper or cadmium were typically greater than additive. Larvae exposed to cadmium, copper or nickel experienced whole body ion loss. Decreases were greatest for Na{sup +} followed by K{sup +} (as high as 19% and 9%, respectively, in 24 h). Additive toxicity between copper and other pharmaceutical compounds such as fluoxetine (Prozac™), β-naphthoflavone, estrogen and 17α-ethinylestradiol were also observed. Similar to metals, acutely toxic concentrations of fluoxetine, β-naphthoflavone and ammonia all decreased whole body Na{sup +} and K{sup +}. Overall, whole body Na{sup +} loss showed the greatest correlation with mortality across a

Metal and pharmaceutical mixtures: Is ion loss the mechanism underlying acute toxicity and widespread additive toxicity in zebrafish?

International Nuclear Information System (INIS)

Alsop, Derek; Wood, Chris M.

2013-01-01

Highlights: •Zebrafish larvae were used to test the acute toxicity of contaminant mixtures. •Interactions were observed between metals, ammonia and pharmaceuticals. •Larval Na + loss was observed with exposure to all acutely toxic contaminants tested. •Water quality criteria should recognize the toxic interactions between contaminants. -- Abstract: The acute toxicities and mechanisms of action of a variety of environmental contaminants were examined using zebrafish larvae (Danio rerio; 4–8 days post fertilization). Toxic interactions were observed between metals. For example, the addition of a sublethal level of nickel (15% of the LC 50 , one third of the LC 01 ) to all copper treatments decreased the copper 96 h LC 50 by 58%, while sublethal copper exposure (6% of the copper LC 50 , 13% of the LC 01 ) decreased the cadmium 96 h LC 50 by 47%. Two predictive models were assessed, the concentration addition (CA) model, which assumes similar mechanisms of action, and the independent action (IA) model, which assumes different mechanisms of action. Quantitative comparisons indicated the CA model performed better than the IA model; the latter tended to underestimate combined toxicity to a greater extent. The effects of mixtures with nickel or ammonia were typically additive, while mixtures with copper or cadmium were typically greater than additive. Larvae exposed to cadmium, copper or nickel experienced whole body ion loss. Decreases were greatest for Na + followed by K + (as high as 19% and 9%, respectively, in 24 h). Additive toxicity between copper and other pharmaceutical compounds such as fluoxetine (Prozac™), β-naphthoflavone, estrogen and 17α-ethinylestradiol were also observed. Similar to metals, acutely toxic concentrations of fluoxetine, β-naphthoflavone and ammonia all decreased whole body Na + and K + . Overall, whole body Na + loss showed the greatest correlation with mortality across a variety of toxicants. We theorize that a disruption of

Control of aliphatic halogenated DBP precursors with multiple drinking water treatment processes: Formation potential and integrated toxicity.

Science.gov (United States)

Zhang, Yimeng; Chu, Wenhai; Yao, Dechang; Yin, Daqiang

2017-08-01

The comprehensive control efficiency for the formation potentials (FPs) of a range of regulated and unregulated halogenated disinfection by-products (DBPs) (including carbonaceous DBPs (C-DBPs), nitrogenous DBPs (N-DBPs), and iodinated DBPs (I-DBPs)) with the multiple drinking water treatment processes, including pre-ozonation, conventional treatment (coagulation-sedimentation, pre-sand filtration), ozone-biological activated carbon (O 3 -BAC) advanced treatment, and post-sand filtration, was investigated. The potential toxic risks of DBPs by combing their FPs and toxicity values were also evaluated. The results showed that the multiple drinking water treatment processes had superior performance in removing organic/inorganic precursors and reducing the formation of a range of halogenated DBPs. Therein, ozonation significantly removed bromide and iodide, and thus reduced the formation of brominated and iodinated DBPs. The removal of organic carbon and nitrogen precursors by the conventional treatment processes was substantially improved by O 3 -BAC advanced treatment, and thus prevented the formation of chlorinated C-DBPs and N-DBPs. However, BAC filtration leads to the increased formation of brominated C-DBPs and N-DBPs due to the increase of bromide/DOC and bromide/DON. After the whole multiple treatment processes, the rank order for integrated toxic risk values caused by these halogenated DBPs was haloacetonitriles (HANs)≫haloacetamides (HAMs)>haloacetic acids (HAAs)>trihalomethanes (THMs)>halonitromethanes (HNMs)≫I-DBPs (I-HAMs and I-THMs). I-DBPs failed to cause high integrated toxic risk because of their very low FPs. The significant higher integrated toxic risk value caused by HANs than other halogenated DBPs cannot be ignored. Copyright © 2017. Published by Elsevier B.V.

Decreased toxicity of aluminium when the ionic strength increases in water; Blir aluminium mindre toksisk naar ionestyrken i vannet oeker?

Energy Technology Data Exchange (ETDEWEB)

Alstad, E W [Oslo Univ. (Norway)

1996-01-01

The conference paper evaluates the acute mortality of fish caused by the toxicity of aluminium in water. The evaluation is based on the polymerization hypothesis. According to the author, the level of toxicity decreases when the concentration and charge of ions increase. The paper presents the preliminary results from the executed experiment. 2 refs., 2 figs., 1 tab.

Fluorine-18-fluorocholine PET/CT parameters predictive for hematological toxicity to radium-223 therapy in castrate-resistant prostate cancer patients with bone metastases: a pilot study.

Science.gov (United States)

Vija Racaru, Lavinia; Sinigaglia, Mathieu; Kanoun, Salim; Ben Bouallègue, Fayçal; Tal, Ilan; Brillouet, Sévérine; Bauriaud-Mallet, Mathilde; Zerdoud, Slimane; Dierickx, Lawrence; Vallot, Delphine; Caselles, Olivier; Gabiache, Erwan; Pascal, Pierre; Courbon, Frederic

2018-05-21

This study aims to predict hematological toxicity induced by Ra therapy. We investigated the value of metabolically active bone tumor volume (MBTV) and total bone lesion activity (TLA) calculated on pretreatment fluorine-18-fluorocholine (F-FCH) PET/CT in castrate-resistant prostate cancer (CRPC) patients with bone metastases treated with Ra radionuclide therapy. F-FCH PET/CT imaging was performed in 15 patients with CRPC before treatment with Ra. Bone metastatic disease was quantified on the basis of the maximum standardized uptake value (SUV), total lesion activity (TLA=MBTV×SUVmean), or MBTV/height (MBTV/H) and TLA/H. F-FCH PET/CT bone tumor burden and activity were analyzed to identify which parameters could predict hematological toxicity [on hemoglobin (Hb), platelets (PLTs), and lymphocytes] while on Ra therapy. Pearson's correlation was used to identify the correlations between age, prostate-specific antigen, and F-FCH PET parameters. MBTV ranged from 75 to 1259 cm (median: 392 cm). TLA ranged from 342 to 7198 cm (median: 1853 cm). Patients benefited from two to six cycles of Ra (n=56 cycles in total). At the end of Ra therapy, five of the 15 (33%) patients presented grade 2/3 toxicity on Hb and lymphocytes, whereas three of the 15 (20%) patients presented grade 2/3 PLT toxicity.Age was correlated negatively with both MBTV (r=-0.612, P=0.015) and TLA (r=-0.596, P=0.018). TLA, TLA/H, and MBTV/H predicted hematological toxicity on Hb, whereas TLA/H and MBTV/H predicted toxicity on PLTs at the end of Ra cycles. Receiver operating characteristic curve analysis allowed to define the cutoffs for MBTV (915 cm) and TLA (4198 cm) predictive for PLT toxicity, with an accuracy of 0.92 and 0.99. Tumor bone burden calculation is feasible with F-FCH PET/CT with freely available open-source software. In this pilot study, baseline F-FCH PET/CT markers (TLA, MBTV) have shown abilities to predict Hb and PLT toxicity after Ra therapy and could be explored for

Toxicity and transfer of polyvinylpyrrolidone-coated silver nanowires in an aquatic food chain consisting of algae, water fleas, and zebrafish

Energy Technology Data Exchange (ETDEWEB)

Chae, Yooeun; An, Youn-Joo, E-mail: anyjoo@konkuk.ac.kr

2016-04-15

Highlights: • Trophic transfer of silver nanowires (AgNWs) was studied in an aquatic food chain. • The transfer of AgNWs from algae to fish via water fleas was observed. • Toxicity of long AgNWs on aquatic organisms is higher than that of short ones. • AgNWs damage the gut of water fleas and may cause undernourishment. • Quantity of lipid droplets increased with increasing exposure concentration. - Abstract: Nanomaterials of various shapes and dimensions are widely used in the medical, chemical, and electronic industries. Multiple studies have reported the ecotoxicological effects of nanaoparticles when released in aquatic and terrestrial ecosystems; however, information on the toxicity of silver nanowires (AgNWs) to freshwater organisms and their transfer through the food webs is limited. In the present study, we aimed to evaluate the toxicity of 10- and 20-μm-long AgNWs to the alga Chlamydomonas reinhardtii, the water flea Daphnia magna, and the zebrafish and study their movement through this three-species food chain using a variety of qualitative and quantitative methods as well as optical techniques. We found that AgNWs directly inhibited the growth of algae and destroyed the digestive organs of water fleas. The results showed that longer AgNWs (20 μm) were more toxic than shorter ones (10 μm) to both algae and water fleas, but shorter AgNWs were accumulated more than longer ones in the body of the fish. Overall, this study suggests that AgNWs are transferred through food chains, and that they affect organisms at higher trophic levels, potentially including humans. Therefore, further studies that take into account environmental factors, food web complexity, and differences between nanomaterials are required to gain better understanding of the impact of nanomaterials on natural communities and human health.

Toxicity and transfer of polyvinylpyrrolidone-coated silver nanowires in an aquatic food chain consisting of algae, water fleas, and zebrafish

International Nuclear Information System (INIS)

Chae, Yooeun; An, Youn-Joo

2016-01-01

Highlights: • Trophic transfer of silver nanowires (AgNWs) was studied in an aquatic food chain. • The transfer of AgNWs from algae to fish via water fleas was observed. • Toxicity of long AgNWs on aquatic organisms is higher than that of short ones. • AgNWs damage the gut of water fleas and may cause undernourishment. • Quantity of lipid droplets increased with increasing exposure concentration. - Abstract: Nanomaterials of various shapes and dimensions are widely used in the medical, chemical, and electronic industries. Multiple studies have reported the ecotoxicological effects of nanaoparticles when released in aquatic and terrestrial ecosystems; however, information on the toxicity of silver nanowires (AgNWs) to freshwater organisms and their transfer through the food webs is limited. In the present study, we aimed to evaluate the toxicity of 10- and 20-μm-long AgNWs to the alga Chlamydomonas reinhardtii, the water flea Daphnia magna, and the zebrafish and study their movement through this three-species food chain using a variety of qualitative and quantitative methods as well as optical techniques. We found that AgNWs directly inhibited the growth of algae and destroyed the digestive organs of water fleas. The results showed that longer AgNWs (20 μm) were more toxic than shorter ones (10 μm) to both algae and water fleas, but shorter AgNWs were accumulated more than longer ones in the body of the fish. Overall, this study suggests that AgNWs are transferred through food chains, and that they affect organisms at higher trophic levels, potentially including humans. Therefore, further studies that take into account environmental factors, food web complexity, and differences between nanomaterials are required to gain better understanding of the impact of nanomaterials on natural communities and human health.

In silico prediction of toxicity of phenols to Tetrahymena pyriformis by using genetic algorithm and decision tree-based modeling approach.

Science.gov (United States)

Abbasitabar, Fatemeh; Zare-Shahabadi, Vahid

2017-04-01

Risk assessment of chemicals is an important issue in environmental protection; however, there is a huge lack of experimental data for a large number of end-points. The experimental determination of toxicity of chemicals involves high costs and time-consuming process. In silico tools such as quantitative structure-toxicity relationship (QSTR) models, which are constructed on the basis of computational molecular descriptors, can predict missing data for toxic end-points for existing or even not yet synthesized chemicals. Phenol derivatives are known to be aquatic pollutants. With this background, we aimed to develop an accurate and reliable QSTR model for the prediction of toxicity of 206 phenols to Tetrahymena pyriformis. A multiple linear regression (MLR)-based QSTR was obtained using a powerful descriptor selection tool named Memorized_ACO algorithm. Statistical parameters of the model were 0.72 and 0.68 for R training 2 and R test 2 , respectively. To develop a high-quality QSTR model, classification and regression tree (CART) was employed. Two approaches were considered: (1) phenols were classified into different modes of action using CART and (2) the phenols in the training set were partitioned to several subsets by a tree in such a manner that in each subset, a high-quality MLR could be developed. For the first approach, the statistical parameters of the resultant QSTR model were improved to 0.83 and 0.75 for R training 2 and R test 2 , respectively. Genetic algorithm was employed in the second approach to obtain an optimal tree, and it was shown that the final QSTR model provided excellent prediction accuracy for the training and test sets (R training 2 and R test 2 were 0.91 and 0.93, respectively). The mean absolute error for the test set was computed as 0.1615. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-Density Real-Time PCR-Based in Vivo Toxicogenomic Screen to Predict Organ-Specific Toxicity

Directory of Open Access Journals (Sweden)

Laszlo G. Puskas

2011-09-01

Full Text Available Toxicogenomics, based on the temporal effects of drugs on gene expression, is able to predict toxic effects earlier than traditional technologies by analyzing changes in genomic biomarkers that could precede subsequent protein translation and initiation of histological organ damage. In the present study our objective was to extend in vivo toxicogenomic screening from analyzing one or a few tissues to multiple organs, including heart, kidney, brain, liver and spleen. Nanocapillary quantitative real-time PCR (QRT-PCR was used in the study, due to its higher throughput, sensitivity and reproducibility, and larger dynamic range compared to DNA microarray technologies. Based on previous data, 56 gene markers were selected coding for proteins with different functions, such as proteins for acute phase response, inflammation, oxidative stress, metabolic processes, heat-shock response, cell cycle/apoptosis regulation and enzymes which are involved in detoxification. Some of the marker genes are specific to certain organs, and some of them are general indicators of toxicity in multiple organs. Utility of the nanocapillary QRT-PCR platform was demonstrated by screening different references, as well as discovery of drug-like compounds for their gene expression profiles in different organs of treated mice in an acute experiment. For each compound, 896 QRT-PCR were done: four organs were used from each of the treated four animals to monitor the relative expression of 56 genes. Based on expression data of the discovery gene set of toxicology biomarkers the cardio- and nephrotoxicity of doxorubicin and sulfasalazin, the hepato- and nephrotoxicity of rotenone, dihydrocoumarin and aniline, and the liver toxicity of 2,4-diaminotoluene could be confirmed. The acute heart and kidney toxicity of the active metabolite SN-38 from its less toxic prodrug, irinotecan could be differentiated, and two novel gene markers for hormone replacement therapy were identified

Problems in assessing the risks of mixtures of contaminants in drinking water

International Nuclear Information System (INIS)

Vanderslice, R.R.; Orme, J.; Ohanian, E.V.; Sonich-Mullin, C.

1989-01-01

In conducting risk assessments on drinking water contaminants, the U.S. Environmental Protection Agency (EPA) attempts to evaluate all available toxicity data to develop Health Advisory (HA) and Maximum Contaminant Level Goal (MCLG) values. The EPA often has grappled with the issues surrounding the toxicity of chemical mixtures, including radioactive contaminants, nitrate/nitrite, and trihalomethanes (THMs). In evaluating the toxicity of chemical mixtures, the EPA's immediate concern is whether the individual HA values and MCLGs are protecting public health when multiple contaminants are present in drinking water. Potential toxic interactions between drinking water contaminants are difficult to predict because experimental studies are generally performed only at high doses relative to environmental levels. Although the contamination of drinking water involves mixtures of contaminants, drinking water regulations are generally based on an assessment of the risks of individual contaminants. This paper discusses three issues of major concern to the EPA: the synergistic effects of solvent mixtures, vehicle effects in laboratory studies, and setting standards for essential trace nutrients where the absorption and/or toxicity are affected by an individual's nutritional status or other dietary components. 12 references

A Seamless Framework for Global Water Cycle Monitoring and Prediction

Science.gov (United States)

Sheffield, J.; Wood, E. F.; Chaney, N.; Fisher, C. K.; Caylor, K. K.

2013-12-01

The Global Earth Observation System of Systems (GEOSS) Water Strategy ('From Observations to Decisions') recognizes that 'water is essential for ensuring food and energy security, for facilitating poverty reduction and health security, and for the maintenance of ecosystems and biodiversity', and that water cycle data and observations are critical for improved water management and water security - especially in less developed regions. The GEOSS Water Strategy has articulated a number of goals for improved water management, including flood and drought preparedness, that include: (i) facilitating the use of Earth Observations for water cycle observations; (ii) facilitating the acquisition, processing, and distribution of data products needed for effective management; (iii) providing expertise, information systems, and datasets to the global, regional, and national water communities. There are several challenges that must be met to advance our capability to provide near real-time water cycle monitoring, early warning of hydrological hazards (floods and droughts) and risk assessment under climate change, regionally and globally. Current approaches to monitoring and predicting hydrological hazards are limited in many parts of the world, and especially in developing countries where national capacity is limited and monitoring networks are inadequate. This presentation describes the development of a seamless monitoring and prediction framework at all time scales that allows for consistent assessment of water variability from historic to current conditions, and from seasonal and decadal predictions to climate change projections. At the center of the framework is an experimental, global water cycle monitoring and seasonal forecast system that has evolved out of regional and continental systems for the US and Africa. The system is based on land surface hydrological modeling that is driven by satellite remote sensing precipitation to predict current hydrological conditions

Discriminating modes of toxic action in mice using toxicity in BALB/c mouse fibroblast (3T3) cells.

Science.gov (United States)

Huang, Tao; Yan, Lichen; Zheng, Shanshan; Wang, Yue; Wang, Xiaohong; Fan, Lingyun; Li, Chao; Zhao, Yuanhui; Martyniuk, Christopher J

2017-12-01

The objective of this study was to determine whether toxicity in mouse fibroblast cells (3T3 cells) could predict toxicity in mice. Synthesized data on toxicity was subjected to regression analysis and it was observed that relationship of toxicities between mice and 3T3 cells was not strong (R 2  = 0.41). Inclusion of molecular descriptors (e.g. ionization, pKa) improved the regression to R 2  = 0.56, indicating that this relationship is influenced by kinetic processes of chemicals or specific toxic mechanisms associated to the compounds. However, to determine if we were able to discriminate modes of action (MOAs) in mice using the toxicities generated from 3T3 cells, compounds were first classified into "baseline" and "reactive" guided by the toxic ratio (TR) for each compound in mice. Sequence, binomial and recursive partitioning analyses provided strong predictions of MOAs in mice based upon toxicities in 3T3 cells. The correct classification of MOAs based on these methods was 86%. Nearly all the baseline compounds predicted from toxicities in 3T3 cells were identified as baseline compounds from the TR in mice. The incorrect assignment of MOAs for some compounds is hypothesized to be due to experimental uncertainty that exists in toxicity assays for both mice and 3T3 cells. Conversely, lack of assignment can also arise because some reactive compounds have MOAs that are different in mice compared to 3T3 cells. The methods developed here are novel and contribute to efforts to reduce animal numbers in toxicity tests that are used to evaluate risks associated with organic pollutants in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Occurrence and Toxicity of Disinfection Byproducts in European Drinking Waters in Relation with the HIWATE Epidemiology Study

Science.gov (United States)

Jeong, Clara H.; Wagner, Elizabeth D.; Siebert, Vincent R.; Anduri, Sridevi; Richardson, Susan D.; Daiber, Eric J.; McKague, A. Bruce; Kogevinas, Manolis; Villanueva, Cristina M.; Goslan, Emma H.; Luo, Wentai; Isabelle, Lorne M.; Pankow, James F.; Grazuleviciene, Regina; Cordier, Sylvaine; Edwards, Susan C.; Righi, Elena; Nieuwenhuijsen, Mark J.; Plewa, Michael J.

2012-01-01

The HIWATE (Health Impacts of long-term exposure to disinfection byproducts in drinking WATEr) project was a systematic analysis that combined the epidemiology on adverse pregnancy outcomes and other health effects with long term exposure to low levels of drinking water disinfection byproducts (DBPs) in the European Union. The present study focused on the relationship of the occurrence and concentration of DBPs with in vitro mammalian cell toxicity. Eleven drinking water samples were collected from 5 European countries. Each sampling location corresponded with an epidemiological study for the HIWATE program. Over 90 DBPs were identified; the range in the number of DBPs and their levels reflected the diverse collection sites, different disinfection processes, and the different characteristics of the source waters. For each sampling site, chronic mammalian cell cytotoxicity correlated highly with the numbers of DBPs identified and the levels of DBP chemical classes. Although there was a clear difference in the genotoxic responses among the drinking waters, these data did not correlate as well with the chemical analyses. Thus, the agents responsible for the genomic DNA damage observed in the HIWATE samples may be due to unresolved associations of combinations of identified DBPs, unknown emerging DBPs that were not identified, or other toxic water contaminants. This study represents the first to integrate quantitative in vitro toxicological data with analytical chemistry and human epidemiologic outcomes for drinking water DBPs. PMID:22958121

Water Pollution Prediction in the Three Gorges Reservoir Area and Countermeasures for Sustainable Development of the Water Environment.

Science.gov (United States)

Li, Yinghui; Huang, Shuaijin; Qu, Xuexin

2017-10-27

The Three Gorges Project was implemented in 1994 to promote sustainable water resource use and development of the water environment in the Three Gorges Reservoir Area (hereafter "Reservoir Area"). However, massive discharge of wastewater along the river threatens these goals; therefore, this study employs a grey prediction model (GM) to predict the annual emissions of primary pollution sources, including industrial wastewater, domestic wastewater, and oily and domestic wastewater from ships, that influence the Three Gorges Reservoir Area water environment. First, we optimize the initial values of a traditional GM (1,1) model, and build a new GM (1,1) model that minimizes the sum of squares of the relative simulation errors. Second, we use the new GM (1,1) model to simulate historical annual emissions data for the four pollution sources and thereby test the effectiveness of the model. Third, we predict the annual emissions of the four pollution sources in the Three Gorges Reservoir Area for a future period. The prediction results reveal the annual emission trends for the major wastewater types, and indicate the primary sources of water pollution in the Three Gorges Reservoir Area. Based on our predictions, we suggest several countermeasures against water pollution and towards the sustainable development of the water environment in the Three Gorges Reservoir Area.

Predictions of soil-water potentials in the north-western Sonoran Desert

Energy Technology Data Exchange (ETDEWEB)

Young, D.R.; Nobel, P.S.

1986-03-01

A simple computer model was developed to predict soil-water potential at a Sonoran Desert site. The variability of precipitation there, coupled with the low water-holding capacity of the sandy soil, result in large temporal and spatial variations in soil-water potential. Predicted soil-water potentials for depths of 5, 10 and 20 cm were in close agreement with measured values as the soil dried after an application of water. Predicted values at a depth of 10 cm, the mean rooting depth of Agave deserti and other succulents common at the study site, also agreed with soil-water potentials measured in the field throughout 1 year. Both soil-water potential and evaporation from the soil surface were very sensitive to simulated changes in the hydraulic conductivity of the soil. The annual duration of soil moisture adequate for succulents was dependent on the rainfall as well as on the spacing and amount of individual rainfalls. The portion of annual precipitation evaporated from the soil surface varied from 73% in a dry year (77 mm precipitation) to 59% in a wet year (597 mm). Besides using the actual precipitation events, simulations were performed using the figures for total monthly precipitation. Based on the average number of rainfalls for a particular month, the rainfall was distributed throughout the month in the model. Predictions using both daily and monthly inputs were in close agreement, especially for the number of days during a year when the soil-water potential was sufficient for water absorption by the succulent plants (above -0.5 MPa).

Human Health Effects Associated with Exposure to Toxic Cyanobacteria

Science.gov (United States)

Reports of toxic cyanobacteria blooms are increasing worldwide. Warming and eutrophic surface water systems support the development of blooms. We examine the evidence for adverse human health effects associated with exposure to toxic blooms in drinking water, recreational water a...

Fate of petroleum hydrocarbons and toxic organics in Louisiana coastal environments

International Nuclear Information System (INIS)

DeLaune, R.D.; Gambrell, R.P.; Pardue, J.H.; Patrick, W.H. Jr.

1991-01-01

Numerous potentially toxic compounds are entering Louisiana's inshore and nearshore coastal environments. To a large degree there is insufficient information for predicting the fate and effect of these materials in aquatic environments. Studies documenting the impact of petroleum hydrocarbons entering Louisiana coastal wetlands are summarized. Also included are research findings on factors affecting the persistence of petroleum hydrocarbons and other toxic organics (pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D), creosote, etc.) in sediment-water systems. Sediment pH and redox conditions have been found to play an important role in the microbial degradation of toxic organics. Most of the hydrocarbons investigated degrade more rapidly under high redox (aerobic) conditions although there are exceptions (e.g., 1,1,1-trichloro-2,2-bis(4-chlorophenyl)(DDT) and polychlorobiphenyls (PCBs)). Some of these compounds, due to their slow degradation in anaerobic sediment, may persist in the system for decades

Analytical solution using computer algebra of a biosensor for detecting toxic substances in water

Science.gov (United States)

Rúa Taborda, María. Isabel

2014-05-01

In a relatively recent paper an electrochemical biosensor for water toxicity detection based on a bio-chip as a whole cell was proposed and numerically solved and analyzed. In such paper the kinetic processes in a miniaturized electrochemical biosensor system was described using the equations for specific enzymatic reaction and the diffusion equation. The numerical solution shown excellent agreement with the measured data but such numerical solution is not enough to design efficiently the corresponding bio-chip. For this reason an analytical solution is demanded. The object of the present work is to provide such analytical solution and then to give algebraic guides to design the bio-sensor. The analytical solution is obtained using computer algebra software, specifically Maple. The method of solution is the Laplace transform, with Bromwich integral and residue theorem. The final solution is given as a series of Bessel functions and the effective time for the bio-sensor is computed. It is claimed that the analytical solutions that were obtained will be very useful to predict further current variations in similar systems with different geometries, materials and biological components. Beside of this the analytical solution that we provide is very useful to investigate the relationship between different chamber parameters such as cell radius and height; and electrode radius.

Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms".

Directory of Open Access Journals (Sweden)

Cristiana Callieri

Full Text Available Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena, a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.

Predicted impacts of future water level decline on monitoring wells using a ground-water model of the Hanford Site

International Nuclear Information System (INIS)

Wurstner, S.K.; Freshley, M.D.

1994-12-01

A ground-water flow model was used to predict water level decline in selected wells in the operating areas (100, 200, 300, and 400 Areas) and the 600 Area. To predict future water levels, the unconfined aquifer system was stimulated with the two-dimensional version of a ground-water model of the Hanford Site, which is based on the Coupled Fluid, Energy, and Solute Transport (CFEST) Code in conjunction with the Geographic Information Systems (GIS) software package. The model was developed using the assumption that artificial recharge to the unconfined aquifer system from Site operations was much greater than any natural recharge from precipitation or from the basalt aquifers below. However, artificial recharge is presently decreasing and projected to decrease even more in the future. Wells currently used for monitoring at the Hanford Site are beginning to go dry or are difficult to sample, and as the water table declines over the next 5 to 10 years, a larger number of wells is expected to be impacted. The water levels predicted by the ground-water model were compared with monitoring well completion intervals to determine which wells will become dry in the future. Predictions of wells that will go dry within the next 5 years have less uncertainty than predictions for wells that will become dry within 5 to 10 years. Each prediction is an estimate based on assumed future Hanford Site operating conditions and model assumptions

Toxicity of water and sediment from stormwater retarding basins to Hydra hexactinella

DEFF Research Database (Denmark)

Rosenkrantz, Rikke Tjørnhøj; Pollino, Carmel A.; Nugegoda, Dayanthi

2008-01-01

of 50 ml/L and 100 ml/L, while the 7 h pulse exposure caused a significant increase in the mean population growth rate compared to the control. Water samples from the two other retarding basins were found non-toxic to H. hexactinella. This is the first study to employ sediment tests with Hydra spp....... on stormwater sediments and a lower population growth rate was observed for organisms exposed to sediment from the Avoca St retarding basins. The behavioral study showed that H. hexactinella tended to avoid the sediment-water interface when exposed to sediment from all retarding basins, compared...... to the reference sediment. Further work is needed to determine the long-term effects of stormwater polluted sediments and acute effects due to organism exposure to short-term high concentrations during rain events. (C) 2008 Elsevier Ltd. All rights reserved....

Water Pollution Prediction in the Three Gorges Reservoir Area and Countermeasures for Sustainable Development of the Water Environment

Directory of Open Access Journals (Sweden)

Yinghui Li

2017-10-01

Full Text Available The Three Gorges Project was implemented in 1994 to promote sustainable water resource use and development of the water environment in the Three Gorges Reservoir Area (hereafter “Reservoir Area”. However, massive discharge of wastewater along the river threatens these goals; therefore, this study employs a grey prediction model (GM to predict the annual emissions of primary pollution sources, including industrial wastewater, domestic wastewater, and oily and domestic wastewater from ships, that influence the Three Gorges Reservoir Area water environment. First, we optimize the initial values of a traditional GM (1,1 model, and build a new GM (1,1 model that minimizes the sum of squares of the relative simulation errors. Second, we use the new GM (1,1 model to simulate historical annual emissions data for the four pollution sources and thereby test the effectiveness of the model. Third, we predict the annual emissions of the four pollution sources in the Three Gorges Reservoir Area for a future period. The prediction results reveal the annual emission trends for the major wastewater types, and indicate the primary sources of water pollution in the Three Gorges Reservoir Area. Based on our predictions, we suggest several countermeasures against water pollution and towards the sustainable development of the water environment in the Three Gorges Reservoir Area.

Water Pollution Prediction in the Three Gorges Reservoir Area and Countermeasures for Sustainable Development of the Water Environment

Science.gov (United States)

Huang, Shuaijin; Qu, Xuexin

2017-01-01

The Three Gorges Project was implemented in 1994 to promote sustainable water resource use and development of the water environment in the Three Gorges Reservoir Area (hereafter “Reservoir Area”). However, massive discharge of wastewater along the river threatens these goals; therefore, this study employs a grey prediction model (GM) to predict the annual emissions of primary pollution sources, including industrial wastewater, domestic wastewater, and oily and domestic wastewater from ships, that influence the Three Gorges Reservoir Area water environment. First, we optimize the initial values of a traditional GM (1,1) model, and build a new GM (1,1) model that minimizes the sum of squares of the relative simulation errors. Second, we use the new GM (1,1) model to simulate historical annual emissions data for the four pollution sources and thereby test the effectiveness of the model. Third, we predict the annual emissions of the four pollution sources in the Three Gorges Reservoir Area for a future period. The prediction results reveal the annual emission trends for the major wastewater types, and indicate the primary sources of water pollution in the Three Gorges Reservoir Area. Based on our predictions, we suggest several countermeasures against water pollution and towards the sustainable development of the water environment in the Three Gorges Reservoir Area. PMID:29077006

Life-cycle testing of receiving waters with Ceriodaphnia dubia

International Nuclear Information System (INIS)

Stewart, A.J.; Beane, B.K.

1995-01-01

Seven-day tests with Ceriodaphnia are commonly used to estimate the toxicity of effluents or receiving waters, but may yield no toxicity outcomes even when pollutants are present (a possible type II error). The authors conducted two sets of full life-cycle tests with C. dubia to (1) see if tests with longer exposure periods revealed evidence for toxicity that might not be evident from shorter tests, and (2) determine the relative importance of water quality versus food as factors influencing C. dubia reproduction. In the first set of tests, daphnids were reared in diluted mineral water (control), water from a stream impacted by coal fly-ash, or water from a mercury-contaminated retention basin. The second set of tests used water from the retention basin only, but this water was either filtered or not filtered, and food was either added or not added. C. dubia survival and reproduction did not differ much among the three waters in the first set of tests. However, both parameters were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia seems to be moderately insensitive to general water-quality factors, but quite sensitive to food-related parameters. Regression analysis showed that the predictability of life-time reproduction of C. dubia from 7-day test results was low in five of six cases. The increase in predictability as a function of test duration also differed among water types (first set of tests), and among treatments (second set of tests). Thus, 7-day tests with C. dubia may be used to quantify water-quality problems, but it may not be possible to reliably extrapolate the results of such tests to longer time scales

Validating potential toxicity assays to assess petroleum hydrocarbon toxicity in polar soil.

Science.gov (United States)

Harvey, Alexis Nadine; Snape, Ian; Siciliano, Steven Douglas

2012-02-01

Potential microbial activities are commonly used to assess soil toxicity of petroleum hydrocarbons (PHC) and are assumed to be a surrogate for microbial activity within the soil ecosystem. However, this assumption needs to be evaluated for frozen soil, in which microbial activity is limited by liquid water (θ(liquid)). Influence of θ(liquid) on in situ toxicity was evaluated and compared to the toxicity endpoints of potential microbial activities using soil from an aged diesel fuel spill at Casey Station, East Antarctica. To determine in situ toxicity, gross mineralization and nitrification rates were determined by the stable isotope dilution technique. Petroleum hydrocarbon-contaminated soil (0-8,000 mg kg(-1)), packed at bulk densities of 1.4, 1.7, and 2.0 g cm(-3) to manipulate liquid water content, was incubated at -5°C for one, two, and three months. Although θ(liquid) did not have a significant effect on gross mineralization or nitrification, gross nitrification was sensitive to PHC contamination, with toxicity decreasing over time. In contrast, gross mineralization was not sensitive to PHC contamination. Toxic response of gross nitrification was comparable to potential nitrification activity (PNA) with similar EC25 (effective concentration causing a 25% effect in the test population) values determined by both measurement endpoints (400 mg kg(-1) for gross nitrification compared to 200 mg kg(-1) for PNA), indicating that potential microbial activity assays are good surrogates for in situ toxicity of PHC contamination in polar regions. Copyright © 2011 SETAC.

Analysis of Toxic and Non-Toxic Alexandrium (Dinophyceae) Species Using Ribosomal RNA Gene Sequences

Science.gov (United States)

1993-02-01

Therriault, J.-C. (1988). Cladistic analysis of electrophoretic variants within the toxic dinoflagellate genus Protogonyaulax. Botanica Marina 31: 39- 51. 8... Botanica Marina 34: 575-587. Halegraeff, G. M., and Bolch, C.J. (1992). Transport of toxic dinoflagellate cysts via ship’s ballast water: implications...analysis of electrophoretic variants within the toxic dinoflagellate genus Protogonv-u.!a,. Botanica Marina 31: 39-51. Curran, J., Baillie, D.L

Linear solvation energy relationships for toxicity of selected organic chemicals to Daphnia pulex and Daphnia magna

Science.gov (United States)

Passino, Dora R.M.; Hickey, James P.; Frank, Anthony M.

1988-01-01

In the Laurentian Great Lakes, more than 300 contaminants have been identified in fish, other biota, water, and sediment. Current hazard assessment of these chemicals by the National Fisheries Research Center-Great Lakes is based on their toxicity, occurrence in the environment, and source. Although scientists at the Center have tested over 70 chemicals with the crustacean Daphnia pulex, the number of experimental data needed to screen the huge array of chemicals in the Great Lakes exceeds the practical capabilities of conducting bioassays. This limitation can be partly circumvented, however, by using mathematical models based on quantitative structure-activity relationships (QSAR) to provide rapid, inexpensive estimates of toxicity. Many properties of chemicals, including toxicity, bioaccumulation and water solubility are well correlated and can be predicted by equations of the generalized linear solvation energy relationships (LSER). The equation we used to model solute toxicity is Toxicity = constant + mVI/100 + s (π* + dδ) + bβm + aαm where VI = intrinsic (Van der Waals) molar volume; π* = molecular dipolarity/polarizability; δ = polarizability 'correction term'; βm = solute hydrogen bond acceptor basicity; and αm = solute hydrogen bond donor acidity. The subscript m designates solute monomer values for α and β. We applied the LSER model to 48-h acute toxicity data (measured as immobilization) for six classes of chemicals detected in Great Lakes fish. The following regression was obtained for Daphnia pulex (concentration = μM): log EC50 = 4.86 - 4.35 VI/100; N = 38, r2 = 0.867, sd = 0.403 We also used the LSER modeling approach to analyze to a large published data set of 24-h acute toxicity for Daphnia magna; the following regression resulted, for eight classes of compounds (concentration = mM): log EC50 = 3.88 - 4.52 VI/100 - 1.62 π* + 1.66 βm - 0.916 αm; N = 62, r2 = 0.859, sd = 0.375 In addition we developed computer software that identifies

Toxicity Identification and Evaluation for the Effluent from Wastewater Treatment Plant in Industrial Complex using D.magna

Science.gov (United States)

Lee, S.; Keum, H.; Chun Sang, H.

2015-12-01

In recent years, the interests on the impacts of industrial wastewater on aquatic ecosystem have increased with concern about ecosystem protection and human health. Whole effluent toxicity tests are used to monitor toxicity by unknown toxic chemicals as well as conventional pollutants from industrial effluent discharges. This study describes the application of TIE (toxicity identification evaluation) procedures to an acutely toxic effluent from a wastewater treatment plant in industrial complex which was toxic to Daphnia magna. In TIE phase I (characterization step), the toxic effects by heavy metals, organic compounds, oxidants, volatile organic compounds, suspended solids and ammonia were screened and revealed that the source of toxicity is far from these toxicants group. Chemical analysis (TIE phase II) on TDS showed that the concentration of chloride ion (6,900 mg/L) was substantially higher than that predicted from EC50 for D. magna. In confirmation step (TIE phase III), chloride ion was demonstrated to be main toxicant in this effluent by the spiking approach, species sensitivity approach and deletion approach. Calcium, potassium, magnesium, sodium, fluorine, sulfate ion concentration (450, 100, 80, 5,300, 0.66, 2,200mg/L) was not shown toxicity from D. magna. Finally, we concluded that chloride was the most contributing toxicant in the waste water treatment plant. Further research activities are needed for technical support of toxicity identification and evaluation on the various types of wastewater treatment plant discharge in Korea. Keywords : TIE, D. magna, Industrial waste water Acknowledgement This research was supported by a grant (15IFIP-B089908-02) from Plant Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government

Removal of soluble toxic metals from water

International Nuclear Information System (INIS)

Buckley, L.P.; Vijayan, S.; McConeghy, G.J.; Maves, S.R.; Martin, J.F.

1990-05-01

The removal of selected, soluble toxic metals from aqueous solutions has been accomplished using a combination of chemical treatment and ultrafiltration. The process has been evaluated at the bench-scale and is undergoing pilot-scale testing. Removal efficiencies in excess of 95-99% have been realized. The test program at the bench-scale investigated the limitations and established the optimum range of operating parameters for the process, while the tests conducted with the pilot-scale process equipment are providing information on longer-term process efficiencies, effective processing rates, and fouling potential of the membranes. With the typically found average concentrations of the toxic metals in groundwaters at Superfund sites used as the feed solution, the process has decreased levels up to 100-fold or more. Experiments were also conducted with concentrated solutions to determine their release from silica-based matrices. The solidified wastes were subjected to EP Toxicity test procedures and met the criteria successfully. The final phase of the program involving a field demonstration at a uranium tailings site will be outlined

The current status of biomarkers for predicting toxicity