Water use and groundwater contamination

International Nuclear Information System (INIS)

Elton, J.J.; Livingstone, B.

1998-01-01

A general review of the groundwater resources in Saskatchewan and their vulnerability to contamination was provided. In particular, the use of water and the effects on water by the oil and gas industry in Saskatchewan were discussed. It was suggested that public concerns over scarcity and contamination of water are gradually changing perceptions about Canada's abundance of water. Saskatchewan's surface water covers 12 per cent of the province. About 90 per cent of the rural populations and 80 per cent of municipalities depend on groundwater supplies. Regulations affecting oil and gas operations that could affect water resources have become more stringent. Techniques used in the detection and monitoring of groundwater affected by salt and petroleum hydrocarbons were described. Electromagnetic surveys are used in detecting salt-affected soils and groundwater. Laboratory analysis of chloride concentrations are needed to define actual chloride concentrations in groundwater. Wells and barriers can be installed to control and recover chloride plumes. Deep well injection and reverse osmosis are other methods, but there is no cheap or simple treatment or disposal method for salt-impacted groundwater. Spills or leaks of petroleum hydrocarbons from various sources can also lead to contamination of groundwater. Various assessment and remediation methods are described. Although there is no scarcity of techniques, all of them are difficult, costly, and may take several years to complete. 11 refs., 1 tab

Geoelectrical mapping and groundwater contamination

Science.gov (United States)

Blum, Rainer

Specific electrical resistivity of near-surface materials is mainly controlled by the groundwater content and thus reacts extremely sensitive to any change in the ion content. Geoelectric mapping is a well-established, simple, and inexpensive technique for observing areal distributions of apparent specific electrical resistivities. These are a composite result of the true resistivities in the underground, and with some additional information the mapping of apparent resistivities can help to delineate low-resistivity groundwater contaminations, typically observed downstream from sanitary landfills and other waste sites. The presence of other good conductors close to the surface, mainly clays, is a serious noise source and has to be sorted out by supporting observations of conductivities in wells and geoelectric depth soundings. The method may be used to monitor the extent of groundwater contamination at a specific time as well as the change of a contamination plume with time, by carrying out repeated measurements. Examples for both are presented.

Review: Micro-organic contaminants in groundwater in China

Science.gov (United States)

Dong, Weihong; Xie, Wei; Su, Xiaosi; Wen, Chuanlei; Cao, Zhipeng; Wan, Yuyu

2018-03-01

Micro-organic contaminants (MOs) in groundwater, which may have adverse effects on human health and ecosystems worldwide, are gaining increased attention in China. A great deal of research has been conducted to investigate their sources, occurrences and behavior in aquifers. This paper reviews the main sources, distribution, concentrations and behavior of a wide range of MOs in groundwater in China. These MOs include well-established persistent organic pollutants—polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), endocrine disrupting chemicals (poly brominated diphenyl ethers (PBDEs), phthalic acid esters (PAEs), bisphenol A (BPA)—and some contaminants of emerging concern such as pharmaceutical and personal care products (antibiotics, caffeine, shampoos) and perfluorinated compounds (PFCs). The results reveal that the main MOs in groundwater are PAHs, organochlorine pesticides (OCPs), PBDEs, PAEs, and antibiotics. Moreover, some PFCs such as perfluorobutane sulfonic acid (PFBS), perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) have only recently been observed in groundwater as emerging organic contaminants. Additionally, most MOs are distributed in populated and industrialized areas such as the southeast coast of China. Finally, industrial emissions, wastewater treatment plant effluents and agricultural wastewater are found to be dominant sources of MOs in groundwater. Based on the existing pollution levels, regulation and amelioration of MOs are warranted.

Uncertainty quantification and experimental design based on unsupervised machine learning identification of contaminant sources and groundwater types using hydrogeochemical data

Science.gov (United States)

Vesselinov, V. V.

2017-12-01

Identification of the original groundwater types present in geochemical mixtures observed in an aquifer is a challenging but very important task. Frequently, some of the groundwater types are related to different infiltration and/or contamination sources associated with various geochemical signatures and origins. The characterization of groundwater mixing processes typically requires solving complex inverse models representing groundwater flow and geochemical transport in the aquifer, where the inverse analysis accounts for available site data. Usually, the model is calibrated against the available data characterizing the spatial and temporal distribution of the observed geochemical species. Numerous geochemical constituents and processes may need to be simulated in these models which further complicates the analyses. As a result, these types of model analyses are typically extremely challenging. Here, we demonstrate a new contaminant source identification approach that performs decomposition of the observation mixtures based on Nonnegative Matrix Factorization (NMF) method for Blind Source Separation (BSS), coupled with a custom semi-supervised clustering algorithm. Our methodology, called NMFk, is capable of identifying (a) the number of groundwater types and (b) the original geochemical concentration of the contaminant sources from measured geochemical mixtures with unknown mixing ratios without any additional site information. We also demonstrate how NMFk can be extended to perform uncertainty quantification and experimental design related to real-world site characterization. The NMFk algorithm works with geochemical data represented in the form of concentrations, ratios (of two constituents; for example, isotope ratios), and delta notations (standard normalized stable isotope ratios). The NMFk algorithm has been extensively tested on synthetic datasets; NMFk analyses have been actively performed on real-world data collected at the Los Alamos National

Applying spatial regression to evaluate risk factors for microbiological contamination of urban groundwater sources in Juba, South Sudan

Science.gov (United States)

Engström, Emma; Mörtberg, Ulla; Karlström, Anders; Mangold, Mikael

2017-06-01

This study developed methodology for statistically assessing groundwater contamination mechanisms. It focused on microbial water pollution in low-income regions. Risk factors for faecal contamination of groundwater-fed drinking-water sources were evaluated in a case study in Juba, South Sudan. The study was based on counts of thermotolerant coliforms in water samples from 129 sources, collected by the humanitarian aid organisation Médecins Sans Frontières in 2010. The factors included hydrogeological settings, land use and socio-economic characteristics. The results showed that the residuals of a conventional probit regression model had a significant positive spatial autocorrelation (Moran's I = 3.05, I-stat = 9.28); therefore, a spatial model was developed that had better goodness-of-fit to the observations. The most significant factor in this model ( p-value 0.005) was the distance from a water source to the nearest Tukul area, an area with informal settlements that lack sanitation services. It is thus recommended that future remediation and monitoring efforts in the city be concentrated in such low-income regions. The spatial model differed from the conventional approach: in contrast with the latter case, lowland topography was not significant at the 5% level, as the p-value was 0.074 in the spatial model and 0.040 in the traditional model. This study showed that statistical risk-factor assessments of groundwater contamination need to consider spatial interactions when the water sources are located close to each other. Future studies might further investigate the cut-off distance that reflects spatial autocorrelation. Particularly, these results advise research on urban groundwater quality.

Isotope hydrology: Investigating groundwater contamination

International Nuclear Information System (INIS)

Dubinchuk, V.; Froehlich, K.; Gonfiantini, R.

1989-01-01

Groundwater quality has worsened in many regions, with sometimes serious consequences. Decontaminating groundwater is an extremely slow process, and sometimes impossible, because of the generally long residence time of the water in most geological formations. Major causes of contamination are poor groundwater management (often dictated by immediate social needs) and the lack of regulations and control over the use and disposal of contaminants. These types of problems have prompted an increasing demand for investigations directed at gaining insight into the behaviour of contaminants in the hydrological cycle. Major objectives are to prevent pollution and degradation of groundwater resources, or, if contamination already has occurred, to identify its origin so that remedies can be proposed. Environmental isotopes have proved to be a powerful tool for groundwater pollution studies. The IAEA has had a co-ordinated research programme since 1987 on the application of nuclear techniques to determine the transport of contaminants in groundwater. An isotope hydrology project is being launched within the framework of the IAEA's regional co-operative programme in Latin America (known as ARCAL). Main objectives are the application of environmental isotopes to problems of groundwater assessment and contamination in Latin America. In 1989, another co-ordinated research programme is planned under which isotopic and other tracers will be used for the validation of mathematical models in groundwater transport studies

Compliance Groundwater Monitoring of Nonpoint Sources - Emerging Approaches

Science.gov (United States)

Harter, T.

2008-12-01

Groundwater monitoring networks are typically designed for regulatory compliance of discharges from industrial sites. There, the quality of first encountered (shallow-most) groundwater is of key importance. Network design criteria have been developed for purposes of determining whether an actual or potential, permitted or incidental waste discharge has had or will have a degrading effect on groundwater quality. The fundamental underlying paradigm is that such discharge (if it occurs) will form a distinct contamination plume. Networks that guide (post-contamination) mitigation efforts are designed to capture the shape and dynamics of existing, finite-scale plumes. In general, these networks extend over areas less than one to ten hectare. In recent years, regulatory programs such as the EU Nitrate Directive and the U.S. Clean Water Act have forced regulatory agencies to also control groundwater contamination from non-incidental, recharging, non-point sources, particularly agricultural sources (fertilizer, pesticides, animal waste application, biosolids application). Sources and contamination from these sources can stretch over several tens, hundreds, or even thousands of square kilometers with no distinct plumes. A key question in implementing monitoring programs at the local, regional, and national level is, whether groundwater monitoring can be effectively used as a landowner compliance tool, as is currently done at point-source sites. We compare the efficiency of such traditional site-specific compliance networks in nonpoint source regulation with various designs of regional nonpoint source monitoring networks that could be used for compliance monitoring. We discuss advantages and disadvantages of the site vs. regional monitoring approaches with respect to effectively protecting groundwater resources impacted by nonpoint sources: Site-networks provide a tool to enforce compliance by an individual landowner. But the nonpoint source character of the contamination

Complex relationship between groundwater velocity and concentration of radioactive contaminants

International Nuclear Information System (INIS)

Kaszeta, F.E.; Bond, F.W.

1980-01-01

This paper uses the results from the Multi-component Mass Transport model to examine the complex interrelationship between groundwater velocity and contaminant dispersion, decay, and retardation with regard to their influence on the contaminant concentration distribution as it travels through the geosphere to the biosphere. The rate of transport of contaminants through the geosphere is governed by groundwater velocity, leach rate, and contaminant retardation. The dominant characteristics of the contaminant concentration distribution are inherited during leaching and modified during transport by dilution, dispersion and decay. For a hypothetical non-decaying, non-dispersing contaminant with no retardation properties, the shape of the source term distribution is governed by the groundwater velocity (dilution) and leach rate. This distribution remains unchanged throughout transport. Under actual conditions, however, dispersion, decay and retardation modify the concentration distribution during both leaching and transport. The amount of dispersion is determined by the distance traveled, but it does have a greater peak-reducing influence on spiked distributions than square-shaped distributions. Decay acts as an overall scaling factor on the concentration distribution. Retardation alters the contaminant travel time and therefore indirectly influences the amount of dilution, dispersion and decay. Simple relationships between individual parameters and groundwater velocity as they influence peak concentration do not exist. For those cases where the source term is not solubility-limited and flow past the waste is independent of regional hydrologic conditions, a threshold concentration occurs at a specific groundwater velocity where the effects of dilution balance those of dispersion and decay

Comparative Analysis of Fluoride Concentrations in Groundwaters in Northern and Southern Ghana: Implications for the Contaminant Sources

Science.gov (United States)

Sunkari, Emmanuel Daanoba; Zango, Musah Saeed; Korboe, Harriet Mateko

2018-04-01

Bongo and Sekyere South districts, both in the northern and southern parts of Ghana, respectively, have high populations living in rural areas and most of them use groundwater for drinking purposes. The groundwater in these areas is prone to contamination from natural and/or artificial sources. Therefore this study aims; (1) to present a comparative analysis of the fluoride concentration in groundwater samples from Bongo and Sekyere South districts and the associated groundwater-rock interaction that may be the cause for the varied fluoride concentrations, (2) to determine the leaching potential of fluoride from the host rocks as the possible mechanism for groundwater contamination. Sixty (60) groundwater samples from active pumping wells and twelve (12) rock samples from outcrops were collected from various communities in the two districts for fluoride concentration and mineralogical analysis. Based on the variations in fluoride concentration, fluoride spatial distribution maps were prepared using empirical Bayesian kriging interpolation method and analysed by means of hierarchical cluster analysis. The fluoride concentration in Bongo district varies between 1.71 and 4.0 mg/L, whereas that in Sekyere South district changes from 0.3 to 0.8 mg/L. From the mineralogical studies, biotite has the highest percentage in the Bongo district and has positive correlation with fluoride concentration in the analysed water samples than in the Sekyere South district. The elevated fluoride concentration in the Bongo district relative to the Sekyere South district is due to the dissolution of biotite in the groundwater and the sufficient groundwater-rock interaction since the water samples are mainly sourced from deeper boreholes. This high fluoride concentration has resulted in a plethora of reported cases of dental fluorosis and other health-related issues in Bongo.

ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 2. Groundwater contaminant mass discharge reduction

DEFF Research Database (Denmark)

Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Bjerg, Poul Løgstrup

2012-01-01

The impact of source mass depletion on the down-gradient contaminant mass discharge was monitored for a 19-month period as a part of a field demonstration of the ZVI-Clay soil mixing remediation technology. Groundwater samples were collected from conventional monitoring wells (120 samples) and a ...... down-gradient contaminant mass discharge reduction (76%) for the parent compound (PCE), while the overall reduction of chlorinated ethenes was smaller (21%)....

Indicators to identify the source of pesticide contamination to groundwater

DEFF Research Database (Denmark)

Thorling, Lærke; Brüsch, Walter; Tuxen, Nina

In Denmark groundwater is synonym with drinking water. The mainstream Danish political approach favors prevention and action at source over advanced treatments of polluted groundwater. The main pollutants are nitrate and pesticides. Pesticides in groundwater can originate from either diffuse or p...

Assessment of groundwater contamination risk using hazard quantification, a modified DRASTIC model and groundwater value, Beijing Plain, China.

Science.gov (United States)

Wang, Junjie; He, Jiangtao; Chen, Honghan

2012-08-15

Groundwater contamination risk assessment is an effective tool for groundwater management. Most existing risk assessment methods only consider the basic contamination process based upon evaluations of hazards and aquifer vulnerability. In view of groundwater exploitation potentiality, including the value of contamination-threatened groundwater could provide relatively objective and targeted results to aid in decision making. This study describes a groundwater contamination risk assessment method that integrates hazards, intrinsic vulnerability and groundwater value. The hazard harmfulness was evaluated by quantifying contaminant properties and infiltrating contaminant load, the intrinsic aquifer vulnerability was evaluated using a modified DRASTIC model and the groundwater value was evaluated based on groundwater quality and aquifer storage. Two groundwater contamination risk maps were produced by combining the above factors: a basic risk map and a value-weighted risk map. The basic risk map was produced by overlaying the hazard map and the intrinsic vulnerability map. The value-weighted risk map was produced by overlaying the basic risk map and the groundwater value map. Relevant validation was completed by contaminant distributions and site investigation. Using Beijing Plain, China, as an example, thematic maps of the three factors and the two risks were generated. The thematic maps suggested that landfills, gas stations and oil depots, and industrial areas were the most harmful potential contamination sources. The western and northern parts of the plain were the most vulnerable areas and had the highest groundwater value. Additionally, both the basic and value-weighted risk classes in the western and northern parts of the plain were the highest, indicating that these regions should deserve the priority of concern. Thematic maps should be updated regularly because of the dynamic characteristics of hazards. Subjectivity and validation means in assessing the

Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

Science.gov (United States)

Aziz, Shuokr Qarani; Maulood, Yousif Ismael

2015-12-01

The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/√s, 0.00004 m/s, and 2.17 × 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated.

Re-thinking stressor interactions: The role of groundwater contamination impacting stream ecosystems

DEFF Research Database (Denmark)

McKnight, Ursula S.; Sonne, Anne Thobo; Rønde, Vinni Kampman

) to quantify the contaminant discharges, and potentially link the chemical impact and stream water quality. Potential pollution sources include two contaminated sites (Grindstedfactory/landfill), aquaculture, waste water discharges, and diffuse sources from agriculture and urban areas. Datafor xenobiotic...... chronic stress level, so even small perturbations on top of changes in water flow or additional chemical stressors may be detrimental to the stream health. To address this issue, we identified contaminant sources and chemical stressors along a 16-km groundwater-fedstream stretch (Grindsted, Denmark...... organic groundwater contaminants, pesticides, heavy metals, general water chemistry, physical conditions and stream flow from three campaigns in 2012 and 2014 were assessed. The measured chemicalconcentrations were converted to toxic units (TU) based on 48-h acute toxicity tests with Daphnia magna...

Nitrate contamination of groundwater: A conceptual management framework

International Nuclear Information System (INIS)

Almasri, Mohammad N.

2007-01-01

In many countries, public concern over the deterioration of groundwater quality from nitrate contamination has grown significantly in recent years. This concern has focused increasingly on anthropogenic sources as the potential cause of the problem. Evidence indicates that the nitrate (NO 3 ) levels routinely exceed the maximum contaminant level (MCL) of 10 mg/l NO 3 -N in many aquifer systems that underlie agriculture-dominated watersheds. Degradation of groundwater quality due to nitrate pollution along with the increasing demand for potable water has motivated the adoption of restoration actions of the contaminated aquifers. Restoration efforts have intensified the dire need for developing protection alternatives and management options such that the ultimate nitrate concentrations at the critical receptors are below the MCL. This paper presents a general conceptual framework for the management of groundwater contamination from nitrate. The management framework utilizes models of nitrate fate and transport in the unsaturated and saturated zones to simulate nitrate concentration at the critical receptors. To study the impact of different management options considering both environmental and economic aspects, the proposed framework incorporates a component of a multi-criteria decision analysis. To enhance spatiality in model development along with the management options, the utilization of a land use map is depicted for the allocation and computation of on-ground nitrogen loadings from the different sources

Contaminant source identification using semi-supervised machine learning

International Nuclear Information System (INIS)

Vesselinov, Velimir Valentinov; Alexandrov, Boian S.; O’Malley, Dan

2017-01-01

Identification of the original groundwater types present in geochemical mixtures observed in an aquifer is a challenging but very important task. Frequently, some of the groundwater types are related to different infiltration and/or contamination sources associated with various geochemical signatures and origins. The characterization of groundwater mixing processes typically requires solving complex inverse models representing groundwater flow and geochemical transport in the aquifer, where the inverse analysis accounts for available site data. Usually, the model is calibrated against the available data characterizing the spatial and temporal distribution of the observed geochemical types. Numerous different geochemical constituents and processes may need to be simulated in these models which further complicates the analyses. In this paper, we propose a new contaminant source identification approach that performs decomposition of the observation mixtures based on Non-negative Matrix Factorization (NMF) method for Blind Source Separation (BSS), coupled with a custom semi-supervised clustering algorithm. Our methodology, called NMFk, is capable of identifying (a) the unknown number of groundwater types and (b) the original geochemical concentration of the contaminant sources from measured geochemical mixtures with unknown mixing ratios without any additional site information. NMFk is tested on synthetic and real-world site data. Finally, the NMFk algorithm works with geochemical data represented in the form of concentrations, ratios (of two constituents; for example, isotope ratios), and delta notations (standard normalized stable isotope ratios).

Emerging organic contaminants in groundwater

OpenAIRE

Stuart, Marianne; Lapworth, Dan

2013-01-01

Emerging organic contaminants (ECs) are compounds now being found in groundwater from agricultural, urban sources that were previously not detectable, or thought to be significant. ECs include pesticides and degradates, pharmaceuticals, industrial compounds, personal care products, fragrances, water treatment by-products, flame retardants and surfactants, as well as ‘life-style’ compounds such as caffeine and nicotine. ECs may have adverse effects on aquatic ecosystems and human health. Freq...

Chemical barriers for controlling groundwater contamination

International Nuclear Information System (INIS)

Morrison, S.J.; Spangler, R.R.

1993-01-01

Chemical barriers are being explored as a low-cost means of controlling groundwater contamination. The barrier can intercept a contaminant plume and prevent migration by transferring contaminants from the groundwater to immobile solids. A chemical barrier can be emplaced in a landfill liner or in an aquifer cutoff wall or can be injected into a contaminant plume. Chemical barriers can be classified as either precipitation barriers or sorption barriers depending upon the dominant mode of contaminant extraction. In a precipitation barrier, contaminants are bound in the structures of newly formed phases; whereas, in a sorption barrier, contaminants attach to the surfaces of preexisting solids by adsorption or some other surface mechanism. Sorption of contaminants is pH dependent. A precipitation barrier can control the pH of the system, but alkaline groundwater may dominate the pH in a sorption barrier. A comparison is made of the characteristics of precipitation and sorption barriers. Experimental data on the extraction of uranium and molybdenum from simulated groundwater are used to demonstrate these concepts. 10 refs., 9 figs., 1 tab

Heavy metal(loid)s and organic contaminants in groundwater in the Pearl River Delta that has undergone three decades of urbanization and industrialization: Distributions, sources, and driving forces.

Science.gov (United States)

Huang, Guanxing; Zhang, Ming; Liu, Chunyan; Li, Liangping; Chen, Zongyu

2018-09-01

Urbanization and industrialization have increased groundwater resource demands, and may drive the change of heavy metal(loid)s and organic chemicals in groundwater in the Pearl River Delta (PRD), southern China. Thus, a comprehensive understanding of the distributions, sources, and driving forces of heavy metal(loid)s and organic chemicals in groundwater in the PRD is vital for water resource management in this region. In this study, eight heavy metal(loid)s and fifty-five organic chemicals in groundwater across the PRD were investigated. The results show that undrinkable groundwater related to heavy metal(loid)s was mainly due to high concentrations of Fe (19.3%) and As (6.8%). Eighteen organic contaminants were detected in groundwater in the PRD, where the most frequently detected organic contaminant was naphthalene, and its detection rate was 2.51%. In 5.3% of all groundwater samples, one or more organic contaminants were found. All detected organic contaminants, except ones without allowable limits, in groundwater were at concentrations below allowable limits of China. The mean concentrations of heavy metal(loid)s in granular aquifers were higher than those in fissured and karst aquifers, especially for Fe and As. Except Se, the mean concentrations of other heavy metal(loid)s and the frequency of detection of organic contaminants in groundwater in urbanized and peri-urban areas were higher than those in non-urbanized areas, especially for Hg, Co, and organic contaminants. Fe, As, and Se in groundwater mainly originated from the release of Fe/As/Se rich sediments. The former two were driven by reduction reactions, while the latter was driven by oxidation resulting from the infiltration of NO 3 - . In contrast, other five heavy metal(loid)s and organic contaminants in groundwater mainly originated from the anthropogenic sources, such as the infiltration of industrial sewage. It is evident that urbanization and industrialization are two powerful driving forces for

[Tracing the Fecal Contamination Sources Based on Bacteroides 16S rRNA PCR- DGGE in Karst Groundwater: Taking Laolongdong Underground River System, Nanshan, Chongqing as an Example].

Science.gov (United States)

Zhang, Hong; Jiang, Yong-jun; Zhang, Yuan-zhu; Duan, Yi-fan; Lü, Xian-fu; He, Qiu-fang

2016-05-15

Microbial contamination in karst groundwater continually increases and tracing the source researches has become a hot topic for international researchers. In this study, Laolongdong underground river at Nanshan, Chongqing was chosen as an example to adopt filter membrane methods to monitor the fecal microbial contaminations including the total bacterial concentration (TB), the total E. coli concentration (TE), the total fecal coliform (FC) and the total fecal Streptocoocci (FS). Bacteriodes was used as an indicator and PCR-DGGE analysis was used to trace fecal contamination sources in karst groundwater. The results suggested that groundwater in this area was seriously polluted by microbes from feces. The concentrations of microbial parameters exceeded limited levels greatly and the total bacterial amounts ranged 10-2.9 x 10⁷ CFU · mL⁻¹, the concentrations of E. coli were between 4.3-4.0 x 10⁵ CFU · mL⁻¹, the max concentration of FC was 1.1 x 10⁶ CFU · (100 mL)⁻¹ and the max concentration of FS was 1.1 x 10⁵ CFU · (100 mL)⁻¹. The FC/FS ratios were mostly over 2 which suggested that the main fecal source in groundwater was human feces. In addition, PCR-DGGE contrastive analysis of Bacteroides communities showed that the similarities between groundwater samples and human feces were in range of 7. 1% -69. 1% , and the similarity of the groundwater sample from Laolongdong underground river outlet was 69.1% . Bacteroides community similarities between groundwater samples and swine feces were in range of 1.1%-53.4%, and the similarity of Laolongdong underground river outlet was merely 1.5%. The similarity data implied that groundwater contamination resulted mainly from human feces, swine feces contamination composed part of animals' fecal contamination, and other animals' feces participated too. Furthermore, sequencing results of PCR-DGGE products revealed that most Bacteroides in groundwater originated from human intestinal tract and human feces.

Groundwater recharge and agricultural contamination in alluvial fan of Eastern Kofu basin, JAPAN

Science.gov (United States)

Nakamura, T.

2009-12-01

Agriculture has significant effects on the rate and composition of groundwater recharge. The chemical loading into groundwater have been dominated by the constituents derived directly or indirectly from agricultural practices and additives. The contamination of groundwater with nitrate is a major public health and environmental concern around the world. The inorganic constituents like, K+, Ca2+, Mg2+, SO42-, Cl- and variety of other minor elements of groundwater are often used as agricultural additives; and the natural occurrence of these elements are dominated by the agricultural sources. A recent study has reported that Kofu basin groundwater aquifer is contaminated by nitrate from agricultural areas because of the fertilizer application for the orchard (Kazama and Yoneyama, 2002; Sakamoto et al., 1997, Nakamura et al., 2007). The water-oxygen and hydrogen stable isotope (δ18O and δD) and nitrate-nitrogen stable isotope (δ15N) of groundwater, river water and precipitation samples were investigated to identify the source of groundwater and nitrate nitrogen contamination in groundwater in the Fuefukigawa and Hikawa_Kanegawa alluvial fans in Kofu basin. The plot of δD versus δ18O values of groundwater, river water and precipitation samples suggest that the groundwater is a mixture of precipitation and river water. And nitrate-nitrogen isotope values have suggested the nitrate contamination of groundwater is from agricultural area. The study revealed positive correlation between groundwater δ18O values and NO3-, Cl-, SO42-, Ca2+, Mg2+ concentration, which shows the agricultural contamination is carried by the recharge of groundwater from precipitation in alluvial fan. Whereas, NO3-, Cl-, SO42-, Ca2+, Mg2+ are diluted by the river water recharges. This study showed the quality of groundwater is resulted from the mixing of water from the different source during the groundwater recharge in the study area. References Kazama F, Yoneyama M (2002) Nitrogen generation

Nitrate contamination of groundwater and its countermeasures

Energy Technology Data Exchange (ETDEWEB)

Mitamura, Hisayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

Petrol contaminated groundwater treatment with air-stripper in Balassagyarmat, Hungary

International Nuclear Information System (INIS)

Szabo, Peter; Bernath, Balazs

2005-01-01

Hydrocarbon contaminated groundwater is a common environmental problem in Hungary. Leakage of underground storage tanks, pipe break or illegal tapping as well as lorry accidents can be mentioned as main reasons. MEGATERRA Ltd. elaborated, adopted and tested several groundwater clean-up methods. These methods are based on detailed survey and investigation, sampling and analysis, delineation of contaminated groundwater, risk assessment, establishment of monitoring wells, pumping tests and remediation action plan. One of these methods was implemented by MEGATERRA Ltd. in Balassagyarmat, Hungary. Contamination source was a 10 m 3 vol. simple wall underground fuel-storage tank, which had been emptied. When the remediation started in April 1998, the petrol had already been accumulated on the ground water table forming a 5-7 m wide and 10-15 m long plume being expanded to SSE-NNW direction. The area of the dissolved hydrocarbon contaminated groundwater-body was 1 000 m 2 and its concentration reached up to 30-40 mg/l TPH. The free-phase hydrocarbon layer was 10 cm thick. For the remediation of contaminated groundwater MEGATERRA Ltd. applied pump and treat method, namely groundwater pumping using extraction well, skimming of free-phase hydrocarbon, stripping of the contaminated ground water in air-stripper tower and draining of the treated groundwater into a drainage ditch. In the centre of the plume we established an extraction well with 300 mm diameter in a 500 mm borehole. Peristaltic skimmer pump was used inside the extraction well to remove the free phase petrol from the ground water surface.Because of the intense volatility of the pollutant we applied aeration (stripping) technology. The extracted contaminated groundwater was cleaned in air-stripper equipment being able to eliminate efficiently the volatile pollutants from the water. The aeration tower is a compact cylindrical shaped column with 650 mm in diameter. Its height depends on the pollutant's type The

Groundwater recharge and agricultural contamination

Science.gov (United States)

Böhlke, J.K.

2002-01-01

Agriculture has had direct and indirect effects on the rates and compositions of groundwater recharge and aquifer biogeochemistry. Direct effects include dissolution and transport of excess quantities of fertilizers and associated materials and hydrologic alterations related to irrigation and drainage. Some indirect effects include changes in water–rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3–, N2, Cl, SO42–, H+, P, C, K, Mg, Ca, Sr, Ba, Ra, and As, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3–, a combination of chemical, isotopic, and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. Groundwater records derived from multi-component hydrostratigraphic data can be used to quantify recharge rates and residence times of water and dissolved contaminants, document past variations in recharging contaminant loads, and identify natural contaminant-remediation processes. These data indicate that many of the world's surficial aquifers contain transient records of changing agricultural contamination from the last half of the 20th century. The transient agricultural groundwater signal has important implications for long-term trends and spatial heterogeneity in discharge.

ARSENIC CONTAMINATION IN GROUNDWATER: A STATISTICAL MODELING

Directory of Open Access Journals (Sweden)

Palas Roy

2013-01-01

Full Text Available High arsenic in natural groundwater in most of the tubewells of the Purbasthali- Block II area of Burdwan district (W.B, India has recently been focused as a serious environmental concern. This paper is intending to illustrate the statistical modeling of the arsenic contaminated groundwater to identify the interrelation of that arsenic contain with other participating groundwater parameters so that the arsenic contamination level can easily be predicted by analyzing only such parameters. Multivariate data analysis was done with the collected groundwater samples from the 132 tubewells of this contaminated region shows that three variable parameters are significantly related with the arsenic. Based on these relationships, a multiple linear regression model has been developed that estimated the arsenic contamination by measuring such three predictor parameters of the groundwater variables in the contaminated aquifer. This model could also be a suggestive tool while designing the arsenic removal scheme for any affected groundwater.

Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses

International Nuclear Information System (INIS)

Kim, Heejung; Kaown, Dugin; Mayer, Bernhard; Lee, Jin-Yong; Hyun, Yunjung; Lee, Kang-Kun

2015-01-01

An integrated study based on hydrogeochemical, microbiological and dual isotopic approaches for nitrate and sulfate was conducted to elucidate sources and biogeochemical reactions governing groundwater contaminants in different seasons and under different land use in a basin of Korea. The land use in the study area is comprised of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and others (3.0%). The concentrations of NO 3 –N and SO 4 2− in groundwater in vegetable fields were highest with 4.2–15.2 mg L −1 and 1.6–19.7 mg L −1 respectively, whereas under paddy fields NO 3 –N concentrations ranged from 0 to 10.7 mg L −1 and sulfate concentrations were ~ 15 mg L −1 . Groundwater with high NO 3 –N concentrations of > 10 mg L −1 had δ 15 N–NO 3 − values ranging from 5.2 to 5.9‰ and δ 18 O values of nitrate between 2.7 and 4.6‰ suggesting that the nitrate was mineralized from soil organic matter that was amended by fertilizer additions. Elevated concentrations of SO 4 2− with δ 34 S–SO 4 2− values between 1 and 6‰ in aquifers in vegetable fields indicated that a mixture of sulfate from atmospheric deposition, mineralization of soil organic matter and from synthetic fertilizers is the source of groundwater sulfate. Elevated δ 18 O–NO 3 − and δ 18 O–SO 4 2− values in samples collected from the paddy fields indicated that denitrification and bacterial sulfate reduction are actively occurring removing sulfate and nitrate from the groundwater. This was supported by high occurrences of denitrifying and sulfate reducing bacteria in groundwater of the paddy fields as evidenced by 16S rRNA pyrosequencing analysis. This study shows that dual isotope techniques combined with microbial data can be a powerful tool for identification of sources and microbial processes affecting NO 3 − and SO 4 2− in groundwater in areas with intensive agricultural land use. - Highlights: • Dual isotope analyses identified

Spatial interpolation methods and geostatistics for mapping groundwater contamination in a coastal area.

Science.gov (United States)

Elumalai, Vetrimurugan; Brindha, K; Sithole, Bongani; Lakshmanan, Elango

2017-04-01

Mapping groundwater contaminants and identifying the sources are the initial steps in pollution control and mitigation. Due to the availability of different mapping methods and the large number of emerging pollutants, these methods need to be used together in decision making. The present study aims to map the contaminated areas in Richards Bay, South Africa and compare the results of ordinary kriging (OK) and inverse distance weighted (IDW) interpolation techniques. Statistical methods were also used for identifying contamination sources. Na-Cl groundwater type was dominant followed by Ca-Mg-Cl. Data analysis indicate that silicate weathering, ion exchange and fresh water-seawater mixing are the major geochemical processes controlling the presence of major ions in groundwater. Factor analysis also helped to confirm the results. Overlay analysis by OK and IDW gave different results. Areas where groundwater was unsuitable as a drinking source were 419 and 116 km 2 for OK and IDW, respectively. Such diverse results make decision making difficult, if only one method was to be used. Three highly contaminated zones within the study area were more accurately identified by OK. If large areas are identified as being contaminated such as by IDW in this study, the mitigation measures will be expensive. If these areas were underestimated, then even though management measures are taken, it will not be effective for a longer time. Use of multiple techniques like this study will help to avoid taking harsh decisions. Overall, the groundwater quality in this area was poor, and it is essential to identify alternate drinking water source or treat the groundwater before ingestion.

Inexact Socio-Dynamic Modeling of Groundwater Contamination Management

Science.gov (United States)

Vesselinov, V. V.; Zhang, X.

2015-12-01

Groundwater contamination may alter the behaviors of the public such as adaptation to such a contamination event. On the other hand, social behaviors may affect groundwater contamination and associated risk levels such as through changing ingestion amount of groundwater due to the contamination. Decisions should consider not only the contamination itself, but also social attitudes on such contamination events. Such decisions are inherently associated with uncertainty, such as subjective judgement from decision makers and their implicit knowledge on selection of whether to supply water or reduce the amount of supplied water under the scenario of the contamination. A socio-dynamic model based on the theories of information-gap and fuzzy sets is being developed to address the social behaviors facing the groundwater contamination and applied to a synthetic problem designed based on typical groundwater remediation sites where the effects of social behaviors on decisions are investigated and analyzed. Different uncertainties including deep uncertainty and vague/ambiguous uncertainty are effectively and integrally addressed. The results can provide scientifically-defensible decision supports for groundwater management in face of the contamination.

Spatial and statistical methods for correlating the interaction between groundwater contamination and tap water exposure in karst regions

Science.gov (United States)

Padilla, I. Y.; Rivera, V. L.; Macchiavelli, R. E.; Torres Torres, N. I.

2016-12-01

Groundwater systems in karst regions are highly vulnerable to contamination and have an enormous capacity to store and rapidly convey pollutants to potential exposure zones over long periods of time. Contaminants in karst aquifers used for drinking water purposes can, therefore, enter distributions lines and the tap water point of use. This study applies spatial and statistical analytical methods to assess potential correlations between contaminants in a karst groundwater system in northern Puerto Rico and exposure in the tap water. It focuses on chlorinated volatile organic compounds (CVOC) and phthalates because of their ubiquitous presence in the environment and the potential public health impacts. The work integrates historical data collected from regulatory agencies and current field measurements involving groundwater and tap water sampling and analysis. Contaminant distributions and cluster analysis is performed with Geographic Information System technology. Correlations between detection frequencies and contaminants concentration in source groundwater and tap water point of use are assessed using Pearson's Chi Square and T-Test analysis. Although results indicate that correlations are contaminant-specific, detection frequencies are generally higher for total CVOC in groundwater than tap water samples, but greater for phthalates in tap water than groundwater samples. Spatial analysis shows widespread distribution of CVOC and phthalates in both groundwater and tap water, suggesting that contamination comes from multiple sources. Spatial correlation analysis indicates that association between tap water and groundwater contamination depends on the source and type of contaminants, spatial location, and time. Full description of the correlations may, however, need to take into consideration variable anthropogenic interventions.

Modeling Groundwater-Surface Water Interaction and Contaminant Transport of Chlorinated Solvent Contaminated Site

Science.gov (United States)

Yimer Ebrahim, Girma; Jonoski, Andreja; van Griensven, Ann; Dujardin, Juliette; Baetelaan, Okke; Bronders, Jan

2010-05-01

Chlorinated-solvent form one of the largest groups of environmental chemicals. Their use and misuse in industry have lead to a large entry of these chemicals into the environment, resulting in widespread dissemination and oftentimes environmental contamination. Chlorinated solvent contamination of groundwater resources has been widely reported. For instance, there has been much interest in the assessment of these contaminant levels and their evolutions with time in the groundwater body below the Vilvoorde-Machelen industrial area (Belgium). The long industrial history of the area has lead to complex patterns of pollution from multiple sources and the site has been polluted to the extent that individual plumes are not definable any more. Understanding of groundwater/surface water interaction is a critical component for determining the fate of contaminant both in streams and ground water due to the fact that groundwater and surface water are in continuous dynamic interaction in the hydrologic cycle. The interaction has practical consequences in the quantity and quality of water in either system in the sense that depletion and/or contamination of one of the system will eventually affect the other one. The transition zone between a stream and its adjacent aquifer referred to as the hyporheic zone plays a critical role in governing contaminant exchange and transformation during water exchange between the two water bodies. The hyporheic zone of Zenne River ( the main receptor ) is further complicated due to the fact that the river banks are artificially trained with sheet piles along its reach extending some 12 m below the surface. This study demonstrates the use of MODFLOW, a widely used modular three-dimensional block-centred finite difference, saturated flow model for simulating the flow and direction of movement of groundwater through aquifer and stream-aquifer interaction and the use of transport model RT3D, a three-dimensional multi-species reactive transport model

Slow arsenic poisoning of the contaminated groundwater users

International Nuclear Information System (INIS)

Uddin, M. M.; Harun-Ar-Rashid, A. K. M.; Hossain, S. M.; Hafiz, M. A.; Nahar, K.; Mubin, S. H.

2006-01-01

This paper gives impact of Arsenic contaminated water on human health as well as overview of the extent and severity of groundwater arsenic contamination in Bangladesh. Scalp hair is the most important part of the human body to monitor the accumulation of this type of poison. Therefore, an experiment has been carried out by Neutron Activation Analysis at Atomic Energy Research Establishment , Savar, Dhaka, Bangladesh on human hair of corresponding tube well water users of these areas to determine the total accumulation of arsenic to their body. Hair samples collected from the region where the groundwater was found highly contaminated with arsenic. The obtained results of arsenic concentration in the lower age (Hb) categories of users (below 12 years of age users) is in the range of 0.33 to 3.29 μg/g (ppm) and that in the Hu categories (upper 12 years of age users) is 0.47 to 6.64 μg/g (ppm). Where as maximum permissible range is 1 ppm certified from WHO. Results show that the peoples are highly affected where the groundwater is highly contaminated with arsenic and acts as the primary source of arsenic poisoning among the peoples of those areas. The results indicate that human population is affected with arsenic locally using the contaminated water for a long time

Use of LCA as decision support for the selection of remedial strategies for remediation of contaminated soil and groundwater

DEFF Research Database (Denmark)

Lemming, Gitte; Hauschild, Michael Zwicky; Bjerg, Poul Løgstrup

2009-01-01

, there is a trade-off between obtaining local beneficial effects from the remediation and generating environmental impacts on the regional and global scale due to the remedial actions. Therefore there is a need for including the impact of soil contaminants that will potentially leach to the groundwater, e......Groundwater is the dominant source of drinking water in Denmark and the general policy is to maintain the groundwater as a clean source of drinking water. The risk of groundwater contamination is therefore often the prime reason for remediating a contaminated site. Chlorinated solvents are among...... the contaminants most frequently found to be threatening the groundwater quality in Denmark and worldwide. Life cycle assessment has recently been applied as part of decision support for contaminated site management and subsurface remediation techniques. Impacts in the groundwater compartment have only gained...

Evaluation of organic contamination in urban groundwater surrounding a municipal landfill, Zhoukou, China.

Science.gov (United States)

Han, D M; Tong, X X; Jin, M G; Hepburn, Emily; Tong, C S; Song, X F

2013-04-01

This paper investigates the organic pollution status of shallow aquifer sediments and groundwater around Zhoukou landfill. Chlorinated aliphatic hydrocarbons, monocylic aromatic hydrocarbons, halogenated aromatic hydrocarbons, organochlorine pesticides and other pesticides, and polycyclic aromatic hydrocarbons (PAHs) have been detected in some water samples. Among the detected eleven PAHs, phenanthrene, fluorine, and fluoranthene are the three dominant in most of the groundwater samples. Analysis of groundwater samples around the landfill revealed concentrations of PAHs ranging from not detected to 2.19 μg/L. The results show that sediments below the waste dump were low in pollution, and the shallow aquifer, at a depth of 18-30 m, was heavily contaminated, particularly during the wet season. An oval-shaped pollution halo has formed, spanning 3 km from west to east and 2 km from south to north, and mainly occurs in groundwater depths of 2-4 m. For PAH source identification, both diagnostic ratios of selected PAHs and principal component analysis were studied, suggesting mixed sources of pyro- and petrogenic derived PAHs in the Zhoukou landfill. Groundwater table fluctuations play an important role in the distribution of organic pollutants within the shallow aquifer. A conceptual model of leachate migration in the Quaternary aquifers surrounding the Zhoukou landfill has been developed to describe the contamination processes based on the major contaminant (PAHs). The groundwater zone contaminated by leachate has been identified surrounding the landfill.

Understanding arsenic contamination of groundwater in Bangladesh

International Nuclear Information System (INIS)

Kabir, Babar

2001-01-01

The problem of water contamination by naturally occurring arsenic confronts governments, public and private utilities, and the development community with a new challenge for implementing operational mitigation activities under difficult conditions of imperfect knowledge - especially for arsenic mitigation for the benefit of the rural poor. With more than a conservative estimate of 20 million of its 130 million people assumed to be drinking contaminated water and another 70 million potentially at risk, Bangladesh is facing what has been described as perhaps the largest mass poisoning in history. High concentrations of naturally occurring arsenic have already been found in water from tens of thousands of tube wells, the main source of potable water, in 59 out of Bangladesh's 64 districts. Arsenic contamination is highly irregular, so tube wells in neighboring locations or even different depths can be safe. Arsenic is extremely hazardous if ingested in drinking water or used in cooking in excess of the maximum permissible limit of 0.01 mg/liter over an extended period of time. Even in the early 1970s, most of Bangladesh's rural population got its drinking water from surface ponds and nearly a quarter of a million children died each year from water-borne diseases. Groundwater now constitutes the major source of drinking water in Bangladesh with 95% of the drinking water coming from underground sources. The provision of tube well water for 97 percent of the rural population has been credited with bringing down the high incidence of diarrheal diseases and contributing to a halving of the infant mortality rate. Paradoxically, the same wells that saved so many lives now pose a threat due to the unforeseen hazard of arsenic. The provenance of arsenic rich minerals in sediments of the Bengal basin as a component of geological formations is believed to be from the Himalayan mountain range. Arsenic has been found in different uncropped geological hard rock formations

Development of Chemical Indicators of Groundwater Contamination Near the Carcass Burial Site

Science.gov (United States)

Kim, H.; Choi, J.; Kim, M.; Choi, J.; Lee, M.; Lee, H.; Jeon, S.; Bang, S.; Noh, H.; Yoo, J.; Park, S.; Kim, H.; Kim, D.; Lee, Y.; Han, J.

2011-12-01

A serious outbreak of foot and mouth disease (FMD) and avian influenza (AI) led to the culling of millions of livestock in South Korea from late 2010 to earlier 2011. Because of the scale of FMD and AI epidemic in Korea and rapid spread of the diseases, mass burial for the disposal of carcass was conducted to halt the outbreak. The improper construction of the burial site or inappropriate management of the carcass burial facility can cause the contamination of groundwater mainly due to the discharges of leachate through the base of disposal pit. The leachate from carcass burial contains by products of carcass decay such as amino acids, nitrate, ammonia and chloride. The presence of these chemical components in groundwater can be used as indicators demonstrating contamination of groundwater with leachate from carcass. The major concern about using these chemical indicators is that other sources including manures, fertilizers and waste waters from human or animal activities already exist in farming area. However, we lack the understanding of how groundwater contamination due to mass burial of carcass can be differentiated from the contamination due to livestock manures which shows similar chemical characteristics. The chemical compositions of the leachate from carcass burial site and the wastewater from livestock manure treatment facilities were compared. The chemical compositions considered include total organic carbon (TOC), total nitrogen (TN), nitrate, organic nitrogen (Organic nitrogen =TN-Ammonium Nitrogen- Nitrate nitrogen), ammonia, chloride, sodium, potassium and amino acids (20 analytes). The ratios of concentrations of the chemical compositions as indicators of contamination were determined to distinguish the sources of contamination in groundwater. Indicators which showed a linear relationship between two factors and revealed a distinct difference between the carcass leachate and livestock manure were chosen. In addition, the background level of the

Groundwater arsenic contamination throughout China.

Science.gov (United States)

Rodríguez-Lado, Luis; Sun, Guifan; Berg, Michael; Zhang, Qiang; Xue, Hanbin; Zheng, Quanmei; Johnson, C Annette

2013-08-23

Arsenic-contaminated groundwater used for drinking in China is a health threat that was first recognized in the 1960s. However, because of the sheer size of the country, millions of groundwater wells remain to be tested in order to determine the magnitude of the problem. We developed a statistical risk model that classifies safe and unsafe areas with respect to geogenic arsenic contamination in China, using the threshold of 10 micrograms per liter, the World Health Organization guideline and current Chinese standard for drinking water. We estimate that 19.6 million people are at risk of being affected by the consumption of arsenic-contaminated groundwater. Although the results must be confirmed with additional field measurements, our risk model identifies numerous arsenic-affected areas and highlights the potential magnitude of this health threat in China.

Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses

Energy Technology Data Exchange (ETDEWEB)

Kim, Heejung [School of Earth and Environmental Sciences (BK21 SEES), Seoul National University, Seoul 151–747 (Korea, Republic of); Kaown, Dugin, E-mail: dugin1@snu.ac.kr [School of Earth and Environmental Sciences (BK21 SEES), Seoul National University, Seoul 151–747 (Korea, Republic of); Mayer, Bernhard [Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Alberta (Canada); Lee, Jin-Yong [Department of Geology, Kangwon National University, Chuncheon 200–701 (Korea, Republic of); Hyun, Yunjung [Planning and Management Group, Korea Environment Institute, Sejong 339-007 (Korea, Republic of); Lee, Kang-Kun [School of Earth and Environmental Sciences (BK21 SEES), Seoul National University, Seoul 151–747 (Korea, Republic of)

2015-11-15

An integrated study based on hydrogeochemical, microbiological and dual isotopic approaches for nitrate and sulfate was conducted to elucidate sources and biogeochemical reactions governing groundwater contaminants in different seasons and under different land use in a basin of Korea. The land use in the study area is comprised of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and others (3.0%). The concentrations of NO{sub 3}–N and SO{sub 4}{sup 2−} in groundwater in vegetable fields were highest with 4.2–15.2 mg L{sup −1} and 1.6–19.7 mg L{sup −1} respectively, whereas under paddy fields NO{sub 3}–N concentrations ranged from 0 to 10.7 mg L{sup −1} and sulfate concentrations were ~ 15 mg L{sup −1}. Groundwater with high NO{sub 3}–N concentrations of > 10 mg L{sup −1} had δ{sup 15}N–NO{sub 3}{sup −} values ranging from 5.2 to 5.9‰ and δ{sup 18}O values of nitrate between 2.7 and 4.6‰ suggesting that the nitrate was mineralized from soil organic matter that was amended by fertilizer additions. Elevated concentrations of SO{sub 4}{sup 2−} with δ{sup 34}S–SO{sub 4}{sup 2−} values between 1 and 6‰ in aquifers in vegetable fields indicated that a mixture of sulfate from atmospheric deposition, mineralization of soil organic matter and from synthetic fertilizers is the source of groundwater sulfate. Elevated δ{sup 18}O–NO{sub 3}{sup −} and δ{sup 18}O–SO{sub 4}{sup 2−} values in samples collected from the paddy fields indicated that denitrification and bacterial sulfate reduction are actively occurring removing sulfate and nitrate from the groundwater. This was supported by high occurrences of denitrifying and sulfate reducing bacteria in groundwater of the paddy fields as evidenced by 16S rRNA pyrosequencing analysis. This study shows that dual isotope techniques combined with microbial data can be a powerful tool for identification of sources and microbial processes affecting NO{sub 3}{sup �

Groundwater pumping effects on contaminant loading management in agricultural regions.

Science.gov (United States)

Park, Dong Kyu; Bae, Gwang-Ok; Kim, Seong-Kyun; Lee, Kang-Kun

2014-06-15

Groundwater pumping changes the behavior of subsurface water, including the location of the water table and characteristics of the flow system, and eventually affects the fate of contaminants, such as nitrate from agricultural fertilizers. The objectives of this study were to demonstrate the importance of considering the existing pumping conditions for contaminant loading management and to develop a management model to obtain a contaminant loading design more appropriate and practical for agricultural regions where groundwater pumping is common. Results from this study found that optimal designs for contaminant loading could be determined differently when the existing pumping conditions were considered. This study also showed that prediction of contamination and contaminant loading management without considering pumping activities might be unrealistic. Motivated by these results, a management model optimizing the permissible on-ground contaminant loading mass together with pumping rates was developed and applied to field investigation and monitoring data from Icheon, Korea. The analytical solution for 1-D unsaturated solute transport was integrated with the 3-D saturated solute transport model in order to approximate the fate of contaminants loaded periodically from on-ground sources. This model was further expanded to manage agricultural contaminant loading in regions where groundwater extraction tends to be concentrated in a specific period of time, such as during the rice-growing season, using a method that approximates contaminant leaching to a fluctuating water table. The results illustrated that the simultaneous management of groundwater quantity and quality was effective and appropriate to the agricultural contaminant loading management and the model developed in this study, which can consider time-variant pumping, could be used to accurately estimate and to reasonably manage contaminant loading in agricultural areas. Copyright © 2014 Elsevier Ltd. All

Evaluation of contaminated groundwater cleanup objectives

International Nuclear Information System (INIS)

Arquiett, C.; Gerke, M.; Datskou, I.

1996-01-01

The US Department of Energy's (DOE's) Environmental Restoration Program will be responsible for remediating the approximately 230 contaminated groundwater sites across the DOE Complex. A major concern for remediation is choosing the appropriate cleanup objective. The cleanup objective chosen will influence the risk to the nearby public during and after remediation; risk to remedial and non-involved workers during remediation; and the cost of remediation. This paper discusses the trends shown in analyses currently being performed at Oak Ridge National Laboratories' (ORNL's) Center for Risk Management (CRM). To evaluate these trends, CRM is developing a database of contaminated sites. This paper examines several contaminated groundwater sites selected for assessment from CRM's data base. The sites in this sample represent potential types of contaminated groundwater sites commonly found at an installation within DOE. The baseline risk from these sites to various receptors is presented. Residual risk and risk during remediation is reported for different cleanup objectives. The cost associated with remediating to each of these objectives is also estimated for each of the representative sites. Finally, the general trends of impacts as a function of cleanup objective will be summarized. The sites examined include the Savannah River site, where there was substantial ground pollution from radionuclides, oil, coal stockpiles, and other forms of groundwater contamination. The effects of various types of groundwater contamination on various types of future user is described. 4 refs., 3 figs., 2 tabs

Ground-water contamination and legal controls in Michigan

Science.gov (United States)

Deutsch, Morris

1963-01-01

The great importance of the fresh ground-water resources of Michigan is evident because 90 percent of the rural and about 70 percent of the total population of the State exclusive of the Detroit metropolitan area are supplied from underground sources. The water-supply and public-health problems that have been caused by some cases of ground-water contamination in the State illustrate the necessity of protecting this vital resource.Manmade and natural contaminants, including many types of chemical and organic matter, have entered many of the numerous aquifers of the State. Aquifers have been contaminated by waste-laden liquids percolating from the surface or from the zone of aeration and by direct injection to the aquifer itself. Industrial and domestic wastes, septic tanks, leaking sewers, flood waters or other poor quality surface waters, mine waters, solids stored or spread at the surface, and even airborne wastes all have been sources of ground-water contamination in Michigan. In addition, naturally occurring saline waters have been induced into other aquifers by overpumping or unrestricted flow from artesian wells, possibly by dewatering operations, and by the deepening of surface stream channels. Vertical migration of saline waters through open holes from formations underlying various important aquifers also has spoiled some of the fresh ground waters in the State. In spite of the contamination that has occurred, however, the total amount of ground water that has been spoiled is only a small part of the total resource. Neither is the contamination so widespread as that of the surface streams of Michigan.Overall legal authority to control most types of ground-water contamination in the State has been assigned by the Michigan Legislature to the Water Resources Commission, although the Department of Conservation and the Health Department also exercise important water-pollution control functions. The Michigan Supreme Court, in an important case upholding the power

Biomarkers study in rainbow trout exposed to industrially contaminated groundwater

Directory of Open Access Journals (Sweden)

Nadjet Benchalgo

2014-03-01

Full Text Available The spill of liquid industrial waste from chemical and petrochemical industries in Mercier lagoons located 20 km south of Montreal, Quebec, caused a major groundwater contamination by industrial contaminants. The aim of this study was to investigate the toxic effects of Mercier groundwater, following 4 and 14 days of exposure to graded concentrations from three wells at increasing distances 1.2, 2.7 and 5.4 km from the source of contamination. Rainbow trout were examined for several biomarkers of defense [ethoxyresorufin O-deethylase (EROD and gluthatione S-transferase (GST activities] and those of tissue damage [lipid peroxidation (LPO and DNA strand breaks]. The results showed that EROD activity was significantly enhanced in hepatic tissue at 1.2 and 5.4 km, whereas inhibition in activity was observed in group at 2.7 km. Therefore, GST activity was significantly increased at 3.1% concentration for the 2.7 km well. No change in LPO was observed. However, a significant induction of DNA strand breaks in liver was obtained at each distance. In conclusion, the data suggest that the release of these contaminants in groundwater leads to increased biotransformation for coplanar aromatic hydrocarbons and DNA damage in groundwater.

Fecal pollution source tracking toolbox for identification, evaluation and characterization of fecal contamination in receiving urban surface waters and groundwater.

Science.gov (United States)

Tran, Ngoc Han; Gin, Karina Yew-Hoong; Ngo, Huu Hao

2015-12-15

The quality of surface waters/groundwater of a geographical region can be affected by anthropogenic activities, land use patterns and fecal pollution sources from humans and animals. Therefore, the development of an efficient fecal pollution source tracking toolbox for identifying the origin of the fecal pollution sources in surface waters/groundwater is especially helpful for improving management efforts and remediation actions of water resources in a more cost-effective and efficient manner. This review summarizes the updated knowledge on the use of fecal pollution source tracking markers for detecting, evaluating and characterizing fecal pollution sources in receiving surface waters and groundwater. The suitability of using chemical markers (i.e. fecal sterols, fluorescent whitening agents, pharmaceuticals and personal care products, and artificial sweeteners) and/or microbial markers (e.g. F+RNA coliphages, enteric viruses, and host-specific anaerobic bacterial 16S rDNA genetic markers) for tracking fecal pollution sources in receiving water bodies is discussed. In addition, this review also provides a comprehensive approach, which is based on the detection ratios (DR), detection frequencies (DF), and fate of potential microbial and chemical markers. DR and DF are considered as the key criteria for selecting appropriate markers for identifying and evaluating the impacts of fecal contamination in surface waters/groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

An economic optimal-control evaluation of achieving/maintaining ground-water quality contaminated from nonpoint agricultural sources

International Nuclear Information System (INIS)

Cole, G.V.

1991-01-01

This study developed a methodology that may be used to dynamically examine the producer/consumer conflict related to nonpoint agricultural chemical contamination of a regional ground-water resource. Available means of obtaining acceptable ground-water quality included pollution-prevention techniques (restricting agricultural-chemical inputs or changing crop-production practices) and end-of-pipe abatement methods. Objectives were to select an agricultural chemical contaminant, estimate the regional agricultural costs associated with restricting the use of the selected chemical, estimate the economic costs associated with point-of-use ground-water contaminant removal and determine the least-cost method for obtaining water quality. The nitrate chemical derived from nitrogen fertilizer was selected as the contaminate. A three-county study area was identified in the Northwest part of Tennessee. Results indicated that agriculture was financially responsible for obtaining clean point-of-use water only when the cost of filtering increased substantially or the population in the region was much larger than currently existed

Remediating Contaminant Plumes in Groundwater with Shallow Excavations Containing Coarse Reactive Media.

Science.gov (United States)

Hudak, Paul F

2018-02-01

A groundwater flow and mass transport model tested the capability of shallow excavations filled with coarse, reactive media to remediate a hypothetical unconfined aquifer with a maximum saturated thickness of 5 m. Modeled as contaminant sinks, the rectangular excavations were 10 m downgradient of an initial contaminant plume originating from a source at the top of the aquifer. The initial plume was approximately 259 m long, 23 m wide, and 5 m thick, with a downgradient tip located approximately 100 m upgradient of the site boundary. The smallest trench capable of preventing offsite migration was 11 m long (measured perpendicular to groundwater flow), 4 m wide (measured parallel to groundwater flow), and 3 m deep. Results of this study suggest that shallow trenches filled with coarse filter media that partially penetrate unconfined aquifers may be a viable alternative for remediating contaminated groundwater at some sites.

The aftermath of the Fukushima nuclear accident: Measures to contain groundwater contamination

Energy Technology Data Exchange (ETDEWEB)

Gallardo, Adrian H., E-mail: adgallardo@geowater.com.au [CONICET (Argentina National Scientific and Technical Research Council), San Luis National University, FCFMyN, Department of Geology, San Luis 5700 (Argentina); Marui, Atsunao [AIST Geological Survey of Japan, Geo-Resources and Environment Institute, Groundwater Research Group, Ibaraki-ken, Tsukuba 305-8567 (Japan)

2016-03-15

Several measures are being implemented to control groundwater contamination at the Fukushima Daiichi Nuclear Plant. This paper presents an overview of work undertaken to contain the spread of radionuclides, and to mitigate releases to the ocean via hydrological pathways. As a first response, contaminated water is being held in tanks while awaiting treatment. Limited storage capacity and the risk of leakage make the measure unsustainable in the long term. Thus, an impervious barrier has been combined with a drain system to minimize the discharge of groundwater offshore. Caesium in seawater at the plant port has largely dropped, although some elevated concentrations are occasionally recorded. Moreover, a dissimilar decline of the radioactivity in fish could indicate additional sources of radionuclides intake. An underground frozen shield is also being constructed around the reactors. This structure would reduce inflows to the reactors and limit the interaction between fresh and contaminated waters. Additional strategies include groundwater abstraction and paving of surfaces to lower water levels and further restrict the mobilisation of radionuclides. Technical difficulties and public distrust pose an unprecedented challenge to the site remediation. Nevertheless, the knowledge acquired during the initial work offers opportunities for better planning and more rigorous decisions in the future. - Highlights: • Measures are being undertaken to manage groundwater contamination in Fukushima. • Methods focus on isolating the source and controlling the radionuclides migration. • Wastewater is being temporarily held in tanks for treatment. • Impervious walls inhibit the transport of contaminants toward the ocean. • Paving and pumping further mitigate the dispersion of pollutants by water.

Identifying sources of groundwater pollution using trace element signatures

International Nuclear Information System (INIS)

Olmez, I.; Hayes, M.J.

1990-01-01

A simple receptor modeling approach has been applied to groundwater pollution studies and has shown that marker trace elements can be used effectively in source identification and apportionment. Groundwater and source materials from one coal-fired and five oil-fired power plants, and one coal-tar deposit site have been analyzed by instrumental neutron activation analysis for more than 20 minor and trace elements. In one of the oil-fired power plants, trace element patterns indicated a leak from the hazardous waste surface impoundments owing to the failure of a hypolon liner. Also, the extent and spatial distribution of groundwater contamination have been determined in a coal-tar deposit site

Simulation–optimization model for groundwater contamination ...

Indian Academy of Sciences (India)

used techniques for groundwater remediation in which the contaminated groundwater is pumped ... ing the affected groundwater aquifer down to some drinking water standard. Several .... For simplicity, rectangular support domain is used in this study. Figure 1 ..... For PAT remediation system, decision variables include the.

Sources, pathways, and relative risks of contaminants in surface water and groundwater: a perspective prepared for the Walkerton inquiry.

Science.gov (United States)

Ritter, Len; Solomon, Keith; Sibley, Paul; Hall, Ken; Keen, Patricia; Mattu, Gevan; Linton, Beth

2002-01-11

On a global scale, pathogenic contamination of drinking water poses the most significant health risk to humans, and there have been countless numbers of disease outbreaks and poisonings throughout history resulting from exposure to untreated or poorly treated drinking water. However, significant risks to human health may also result from exposure to nonpathogenic, toxic contaminants that are often globally ubiquitous in waters from which drinking water is derived. With this latter point in mind, the objective of this commission paper is to discuss the primary sources of toxic contaminants in surface waters and groundwater, the pathways through which they move in aquatic environments, factors that affect their concentration and structure along the many transport flow paths, and the relative risks that these contaminants pose to human and environmental health. In assessing the relative risk of toxic contaminants in drinking water to humans, we have organized our discussion to follow the classical risk assessment paradigm, with emphasis placed on risk characterization. In doing so, we have focused predominantly on toxic contaminants that have had a demonstrated or potential effect on human health via exposure through drinking water. In the risk assessment process, understanding the sources and pathways for contaminants in the environment is a crucial step in addressing (and reducing) uncertainty associated with estimating the likelihood of exposure to contaminants in drinking water. More importantly, understanding the sources and pathways of contaminants strengthens our ability to quantify effects through accurate measurement and testing, or to predict the likelihood of effects based on empirical models. Understanding the sources, fate, and concentrations of chemicals in water, in conjunction with assessment of effects, not only forms the basis of risk characterization, but also provides critical information required to render decisions regarding regulatory

Review of risk from potential emerging contaminants in UK groundwater

OpenAIRE

Stuart, Marianne; Lapworth, Dan; Crane, Emily; Hart, Alwyn

2012-01-01

This paper provides a review of the types of emerging organic groundwater contaminants (EGCs) which are beginning to be found in the UK. EGCs are compounds being found in groundwater that were previously not detectable or known to be significant and can come from agricultural, urban and rural point sources. EGCs include nanomaterials, pesticides, pharmaceuticals, industrial compounds, personal care products, fragrances, water treatment by-products, flame retardants and surfactants, as well a...

Sources and controls of Arsenic contamination in groundwater of Rajnandgaon and Kanker District, Chattisgarh Central India

Science.gov (United States)

Shukla, Dericks Praise; Dubey, C. S.; Singh, Ningthoujam P.; Tajbakhsh, M.; Chaudhry, M.

2010-12-01

SummaryA high concentration of Arsenic (As) contamination in ground water has been reported in the village of Kaudikasa in Rajnandgaon district, wherein around 10% of the population is suffering from As-borne diseases. The region does not share any demographic or geological similarity with the sedimentary aquifers of the Bengal Delta Plain in Eastern India, but represents an igneous terrain with elevated As concentrations in groundwater. There is limited information about the source of As in groundwater and its mobility constraints. In this area, almost all the wells are located in the granitic terrain with pegmatitic intrusions. Most of these wells are characterized by As concentration above the World Health Organization ( WHO, 1999) and the BIS (Bureau of Indian Standards) standards, with the highest being found in a well with more than 250 μg/L of As. Here we report petrographic studies of the granitic host rock and X-ray diffraction results that indicate that altered realgar (α-As 4S 4), para realgar (AsS), and/or tennantite (Cu 12As 4S 13), are the main mineral that contain As. This element is leached during the weathering and water-rock interactions. Microprobe analysis of the altered realgar grains of in pegmatitic intrusions of the host granite indicate 23-27 wt.% As. Remote sensing is useful to delineate the source of this contaminant, which appears to lie at the intersection of a mineralized NW-SE and N-S lineaments associated with the Kotri rift zone. These lineaments are structurally controlled as rifting followed by thrusting and other types of faulting caused left-lateral displacement of N-S Kotri lineament along a NW-SE fault plane showing sinistral shearing. This process caused water drainage in the areas to flow along these highly mineralized weak zones. Thus, the water becomes highly contaminated due to leaching of minerals at the intersection of these lineaments, clearly visible at two areas of high contamination that lie very near to this

ARSENIC CONTAMINATION IN GROUNDWATER: A STATISTICAL MODELING

OpenAIRE

Palas Roy; Naba Kumar Mondal; Biswajit Das; Kousik Das

2013-01-01

High arsenic in natural groundwater in most of the tubewells of the Purbasthali- Block II area of Burdwan district (W.B, India) has recently been focused as a serious environmental concern. This paper is intending to illustrate the statistical modeling of the arsenic contaminated groundwater to identify the interrelation of that arsenic contain with other participating groundwater parameters so that the arsenic contamination level can easily be predicted by analyzing only such parameters. Mul...

Unintentional contaminant transfer from groundwater to the vadose zone during source zone remediation of volatile organic compounds.

Science.gov (United States)

Chong, Andrea D; Mayer, K Ulrich

2017-09-01

Historical heavy use of chlorinated solvents in conjunction with improper disposal practices and accidental releases has resulted in widespread contamination of soils and groundwater in North America and worldwide. As a result, remediation of chlorinated solvents is required at many sites. For source zone treatment, common remediation strategies include in-situ chemical oxidation (ISCO) using potassium or sodium permanganate, and the enhancement of biodegradation by primary substrate addition. It is well known that these remediation methods tend to generate gas (carbon dioxide (CO 2 ) in the case of ISCO using permanganate, CO 2 and methane (CH 4 ) in the case of bioremediation). Vigorous gas generation in the presence of chlorinated solvents, which are categorized as volatile organic contaminants (VOCs), may cause gas exsolution, ebullition and stripping of the contaminants from the treatment zone. This process may lead to unintentional 'compartment transfer', whereby VOCs are transported away from the contaminated zone into overlying clean sediments and into the vadose zone. To this extent, benchtop column experiments were conducted to quantify the effect of gas generation during remediation of the common chlorinated solvent trichloroethylene (TCE/C 2 Cl 3 H). Both ISCO and enhanced bioremediation were considered as treatment methods. Results show that gas exsolution and ebullition occurs for both remediation technologies. Facilitated by ebullition, TCE was transported from the source zone into overlying clean groundwater and was subsequently released into the column headspace. For the case of enhanced bioremediation, the intermediate degradation product vinyl chloride (VC) was also stripped from the treatment zone. The concentrations measured in the headspace of the columns (TCE ∼300ppm in the ISCO column, TCE ∼500ppm and VC ∼1380ppm in the bioremediation column) indicate that substantial transfer of VOCs to the vadose zone is possible. These findings

Groundwater Pollution Sources Apportionment in the Ghaen Plain, Iran

Directory of Open Access Journals (Sweden)

Mohammad Reza Vesali Naseh

2018-01-01

Full Text Available Although Iran’s Ghaen Plain provides saffron to much of the world, no regional groundwater quality (GQ assessment has yet been undertaken. Given the region’s potential for saltwater intrusion and heavy metal contamination, it is important to assess the GQ and determine its main probable source of pollution (MPSP. Such knowledge would allow for informed mitigation or elimination of the potential adverse health effects of this groundwater through its use as drinking water, or indirectly as a result of the consumption of groundwater-irrigated crops. Total dissolved solids, sodium, and chloride in the water of the majority of 16 wells sampled within the region exceeded World Health Organization and Iranian permissible standards for drinking water. The groundwater proved to only be suitable for irrigating salt tolerant crops under good drainage conditions. Due to the precipitation of calcium carbonate in the water supply facilities, the water from all wells was deemed unsuitable for industrial purposes. Heavy metal pollution and contamination indices showed no groundwater contamination. Analysis of ionic ratios and the application of principal components analysis indicated the MPSP to be saltwater intrusion, with the geology subtending the plain, and to a lesser extent, anthropogenic activities. Reducing groundwater withdrawals, particularly those for agricultural production by using high performance irrigation methods could reduce saltwater intrusion and improve GQ in the Ghaen Plain.

Groundwater Pollution Sources Apportionment in the Ghaen Plain, Iran.

Science.gov (United States)

Vesali Naseh, Mohammad Reza; Noori, Roohollah; Berndtsson, Ronny; Adamowski, Jan; Sadatipour, Elaheh

2018-01-22

Although Iran's Ghaen Plain provides saffron to much of the world, no regional groundwater quality (GQ) assessment has yet been undertaken. Given the region's potential for saltwater intrusion and heavy metal contamination, it is important to assess the GQ and determine its main probable source of pollution (MPSP). Such knowledge would allow for informed mitigation or elimination of the potential adverse health effects of this groundwater through its use as drinking water, or indirectly as a result of the consumption of groundwater-irrigated crops. Total dissolved solids, sodium, and chloride in the water of the majority of 16 wells sampled within the region exceeded World Health Organization and Iranian permissible standards for drinking water. The groundwater proved to only be suitable for irrigating salt tolerant crops under good drainage conditions. Due to the precipitation of calcium carbonate in the water supply facilities, the water from all wells was deemed unsuitable for industrial purposes. Heavy metal pollution and contamination indices showed no groundwater contamination. Analysis of ionic ratios and the application of principal components analysis indicated the MPSP to be saltwater intrusion, with the geology subtending the plain, and to a lesser extent, anthropogenic activities. Reducing groundwater withdrawals, particularly those for agricultural production by using high performance irrigation methods could reduce saltwater intrusion and improve GQ in the Ghaen Plain.

Topsoil N-budget model in orchard farming to evaluate groundwater nitrate contamination

Science.gov (United States)

Wijayanti, Yureana; Budihardjo, Kadarwati; Sakamoto, Yasushi; Setyandito, Oki

2017-12-01

A small scale field research was conducted in an orchard farming area in Kofu, Japan, where nitrate contamination was found in groundwater. The purpose of assessing the leaching of nitrate in this study is to understand the transformation and transport process of N-source in topsoil that leads to nitrate contamination of groundwater. In order to calculate N-budget in the soil, the model was utilized to predict the nitrogen leaching. In this res earch, the N-budget model was modified to evaluate influence of precipitation and application pattern of fertilizer and manure compost. The result shows that at the time before the addition of manure compost and fertilizer, about 75% of fertilizer leach from topsoil. Every month, the average remaining nitrate in soil from fertilizer and manure compost are 22% and 50%, respectively. The accumulation of this monthly manure compost nitrate, which stored in soil, should be carefully monitored. It could become the potential source of nitrate leaching to groundwater in the future.

Groundwater isotopic variations in a uranium mining site: subsidies for contamination studies

International Nuclear Information System (INIS)

Araujo, V. P. de

2017-01-01

The Caetite Experimental Basin (CEB), located in the semi-arid region of Northeastern Brazil, faces not only the challenges associated with water scarcity but also the potential contamination processes due to mining activity. The only active uranium production center in Brazil (URA) is located in this watershed and the sustainability of mining and milling operations, as well as the survival of the local community, is highly dependent on the availability of groundwater resources. This paper analyzes the stable isotopes variation of Deuterium ("2H) and Oxygen-18 ("1"8O) in CEB's groundwater to investigate its dynamics and mixing of water sources as part of initial efforts to characterize the hydrogeology of this area for future contamination and recharge studies. Measurements of δ"2H, δ"1"8O, total dissolved solids (TDS), pH, and electrical conductivity (EC) were carried out in water samples from 27 wells. A total of 98 groundwater samples were analyzed during the dry and wet seasons from 2012 to 2014. All the groundwater samples plotted below the local meteoric line toward more enriched δ"1"8O values, an indicative of evaporation process. "2H and "1"8O data suggests that the main source of groundwater recharge is local precipitation and there is no mixing of infiltrating rainwater with older groundwater. These results provide evidence that the aquifer system in the CEB has a relatively fast turnover time, which contribute to the vulnerability of the aquifer to contamination. These findings are corroborated by the low TDS and EC values indicative of short time in water-rock interaction. (author)

Groundwater isotopic variations in a uranium mining site: subsidies for contamination studies

Energy Technology Data Exchange (ETDEWEB)

Araujo, V. P. de [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Engenharia Nuclear; Sobrinho, G.A.N.; Freitas, L.D.; Franklin, M.R., E-mail: mariza@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-09-01

The Caetite Experimental Basin (CEB), located in the semi-arid region of Northeastern Brazil, faces not only the challenges associated with water scarcity but also the potential contamination processes due to mining activity. The only active uranium production center in Brazil (URA) is located in this watershed and the sustainability of mining and milling operations, as well as the survival of the local community, is highly dependent on the availability of groundwater resources. This paper analyzes the stable isotopes variation of Deuterium ({sup 2}H) and Oxygen-18 ({sup 18}O) in CEB's groundwater to investigate its dynamics and mixing of water sources as part of initial efforts to characterize the hydrogeology of this area for future contamination and recharge studies. Measurements of δ{sup 2}H, δ{sup 18}O, total dissolved solids (TDS), pH, and electrical conductivity (EC) were carried out in water samples from 27 wells. A total of 98 groundwater samples were analyzed during the dry and wet seasons from 2012 to 2014. All the groundwater samples plotted below the local meteoric line toward more enriched δ{sup 18}O values, an indicative of evaporation process. {sup 2}H and {sup 18}O data suggests that the main source of groundwater recharge is local precipitation and there is no mixing of infiltrating rainwater with older groundwater. These results provide evidence that the aquifer system in the CEB has a relatively fast turnover time, which contribute to the vulnerability of the aquifer to contamination. These findings are corroborated by the low TDS and EC values indicative of short time in water-rock interaction. (author)

Source partitioning of anthropogenic groundwater nitrogen in a mixed-use landscape, Tutuila, American Samoa

Science.gov (United States)

Shuler, Christopher K.; El-Kadi, Aly I.; Dulai, Henrietta; Glenn, Craig R.; Fackrell, Joseph

2017-12-01

This study presents a modeling framework for quantifying human impacts and for partitioning the sources of contamination related to water quality in the mixed-use landscape of a small tropical volcanic island. On Tutuila, the main island of American Samoa, production wells in the most populated region (the Tafuna-Leone Plain) produce most of the island's drinking water. However, much of this water has been deemed unsafe to drink since 2009. Tutuila has three predominant anthropogenic non-point-groundwater-pollution sources of concern: on-site disposal systems (OSDS), agricultural chemicals, and pig manure. These sources are broadly distributed throughout the landscape and are located near many drinking-water wells. Water quality analyses show a link between elevated levels of total dissolved groundwater nitrogen (TN) and areas with high non-point-source pollution density, suggesting that TN can be used as a tracer of groundwater contamination from these sources. The modeling framework used in this study integrates land-use information, hydrological data, and water quality analyses with nitrogen loading and transport models. The approach utilizes a numerical groundwater flow model, a nitrogen-loading model, and a multi-species contaminant transport model. Nitrogen from each source is modeled as an independent component in order to trace the impact from individual land-use activities. Model results are calibrated and validated with dissolved groundwater TN concentrations and inorganic δ15N values, respectively. Results indicate that OSDS contribute significantly more TN to Tutuila's aquifers than other sources, and thus should be prioritized in future water-quality management efforts.

The field application of an immunoassay-based test for petroleum fuels contamination in groundwater

International Nuclear Information System (INIS)

Carter, K.R.

1994-01-01

The recent development of low-cost, rapid field analytical tests for petroleum fuels based on immunoassay technology has provided an on-site tool for the cost-effective, accurate assessment of groundwater contamination. The method allows for rapid, direct measurement of contaminant concentration. The method has been used for a variety of applications including surface water runoff testing and groundwater monitoring well siting. The PETRO RISc Water Test can be used to substantially reduce the cost of monitoring well installation. Current, monitoring wells are placed based on knowledge of the location of the source of contamination, the size of the release, the time elapsed since the release began, and the hydrogeology of the site. While the location of the source is generally known with some precision, the hydrogeology of the site and the timing of the release rarely are. This results in the need for an ''educated guess'' regarding the drilling location for monitoring wells that are installed to provide long term feedback on groundwater contamination. The tests have the greatest sensitivity to aliphatic compounds in the range of six to ten carbons and aromatic compounds such as toluene, xylene, and naphthalene

Uranium in groundwater--Fertilizers versus geogenic sources.

Science.gov (United States)

Liesch, Tanja; Hinrichsen, Sören; Goldscheider, Nico

2015-12-01

Due to its radiological and toxicological properties even at low concentration levels, uranium is increasingly recognized as relevant contaminant in drinking water from aquifers. Uranium originates from different sources, including natural or geogenic, mining and industrial activities, and fertilizers in agriculture. The goal of this study was to obtain insights into the origin of uranium in groundwater while differentiating between geogenic sources and fertilizers. A literature review concerning the sources and geochemical processes affecting the occurrence and distribution of uranium in the lithosphere, pedosphere and hydrosphere provided the background for the evaluation of data on uranium in groundwater at regional scale. The state of Baden-Württemberg, Germany, was selected for this study, because of its hydrogeological and land-use diversity, and for reasons of data availability. Uranium and other parameters from N=1935 groundwater monitoring sites were analyzed statistically and geospatially. Results show that (i) 1.6% of all water samples exceed the German legal limit for drinking water (10 μg/L); (ii) The range and spatial distribution of uranium and occasional peak values seem to be related to geogenic sources; (iii) There is a clear relation between agricultural land-use and low-level uranium concentrations, indicating that fertilizers generate a measurable but low background of uranium in groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Arsenic contaminated groundwater and its treatment options in Bangladesh.

Science.gov (United States)

Jiang, Jia-Qian; Ashekuzzaman, S M; Jiang, Anlun; Sharifuzzaman, S M; Chowdhury, Sayedur Rahman

2012-12-20

Arsenic (As) causes health concerns due to its significant toxicity and worldwide presence in drinking water and groundwater. The major sources of As pollution may be natural process such as dissolution of As-containing minerals and anthropogenic activities such as percolation of water from mines, etc. The maximum contaminant level for total As in potable water has been established as 10 µg/L. Among the countries facing As contamination problems, Bangladesh is the most affected. Up to 77 million people in Bangladesh have been exposed to toxic levels of arsenic from drinking water. Therefore, it has become an urgent need to provide As-free drinking water in rural households throughout Bangladesh. This paper provides a comprehensive overview on the recent data on arsenic contamination status, its sources and reasons of mobilization and the exposure pathways in Bangladesh. Very little literature has focused on the removal of As from groundwaters in developing countries and thus this paper aims to review the As removal technologies and be a useful resource for researchers or policy makers to help identify and investigate useful treatment options. While a number of technological developments in arsenic removal have taken place, we must consider variations in sources and quality characteristics of As polluted water and differences in the socio-economic and literacy conditions of people, and then aim at improving effectiveness in arsenic removal, reducing the cost of the system, making the technology user friendly, overcoming maintenance problems and resolving sludge management issues.

Arsenic Contaminated Groundwater and Its Treatment Options in Bangladesh

Science.gov (United States)

Jiang, Jia-Qian; Ashekuzzaman, S. M.; Jiang, Anlun; Sharifuzzaman, S. M.; Chowdhury, Sayedur Rahman

2012-01-01

Arsenic (As) causes health concerns due to its significant toxicity and worldwide presence in drinking water and groundwater. The major sources of As pollution may be natural process such as dissolution of As-containing minerals and anthropogenic activities such as percolation of water from mines, etc. The maximum contaminant level for total As in potable water has been established as 10 µg/L. Among the countries facing As contamination problems, Bangladesh is the most affected. Up to 77 million people in Bangladesh have been exposed to toxic levels of arsenic from drinking water. Therefore, it has become an urgent need to provide As-free drinking water in rural households throughout Bangladesh. This paper provides a comprehensive overview on the recent data on arsenic contamination status, its sources and reasons of mobilization and the exposure pathways in Bangladesh. Very little literature has focused on the removal of As from groundwaters in developing countries and thus this paper aims to review the As removal technologies and be a useful resource for researchers or policy makers to help identify and investigate useful treatment options. While a number of technological developments in arsenic removal have taken place, we must consider variations in sources and quality characteristics of As polluted water and differences in the socio-economic and literacy conditions of people, and then aim at improving effectiveness in arsenic removal, reducing the cost of the system, making the technology user friendly, overcoming maintenance problems and resolving sludge management issues. PMID:23343979

A model for evaluating the three-dimensional groundwater dividing pathline between a contaminant source and a partially penetrating water-supply well

Science.gov (United States)

Harmsen, Eric W.; Converse, James C.; Anderson, Mary P.; Hoopes, John A.

1991-09-01

Effluent from septic tank-drainfields can degrade groundwater quality and contaminate nearby water-supply wells. Such groundwater contamination is a problem in the unsewered subdivisions of the sand plain of central Wisconsin, for example. To help planners minimize the risk of direct contamination of a water-supply well by a septic system, a model was developed to estimate the location of the critical dividing pathline between a rectangular contaminant source (the septic tank drainfield) and a partially penetrating pumping well. The model is capable of handling three-dimensional, transient flow in an unconfined, homogeneous, anisotropic aquifer of infinite areal extent, under a regional horizontal hydraulic gradient. Model results are in very good agreement with several other numerical and analytical models. Examples are given for which the safe, horizontal and vertical separation distances to avoid well water contamination are determined for typical central Wisconsin sand plain conditions. A companion paper (Harmsen et al., 1991) describes the application of this model, using a Monte-Carlo analysis, to study the variation of these separation distances in the Wisconsin sand plain. The model can also be applied to larger scale problems and, therefore, could be useful in implementing the U.S. Environmental Protection Agency's new well head protection program.

Groundwater Pollution Source Identification using Linked ANN-Optimization Model

Science.gov (United States)

Ayaz, Md; Srivastava, Rajesh; Jain, Ashu

2014-05-01

Groundwater is the principal source of drinking water in several parts of the world. Contamination of groundwater has become a serious health and environmental problem today. Human activities including industrial and agricultural activities are generally responsible for this contamination. Identification of groundwater pollution source is a major step in groundwater pollution remediation. Complete knowledge of pollution source in terms of its source characteristics is essential to adopt an effective remediation strategy. Groundwater pollution source is said to be identified completely when the source characteristics - location, strength and release period - are known. Identification of unknown groundwater pollution source is an ill-posed inverse problem. It becomes more difficult for real field conditions, when the lag time between the first reading at observation well and the time at which the source becomes active is not known. We developed a linked ANN-Optimization model for complete identification of an unknown groundwater pollution source. The model comprises two parts- an optimization model and an ANN model. Decision variables of linked ANN-Optimization model contain source location and release period of pollution source. An objective function is formulated using the spatial and temporal data of observed and simulated concentrations, and then minimized to identify the pollution source parameters. In the formulation of the objective function, we require the lag time which is not known. An ANN model with one hidden layer is trained using Levenberg-Marquardt algorithm to find the lag time. Different combinations of source locations and release periods are used as inputs and lag time is obtained as the output. Performance of the proposed model is evaluated for two and three dimensional case with error-free and erroneous data. Erroneous data was generated by adding uniformly distributed random error (error level 0-10%) to the analytically computed concentration

Understanding shallow groundwater contamination in Bwaise slum, Kampala, Uganda

Science.gov (United States)

Nyenje, P. M.; Havik, J.; Foppen, J. W.; Uhlenbrook, S.

2012-04-01

Groundwater in unsewered urban areas is heavily contaminated by onsite sanitation activities and is believed to be an important source of nutrients ex-filtrating into streams and thus contributing to eutrophication of Lakes in urban areas. Currently the fate of nutrients and especially phosphorus leached into groundwater in such areas is not well known. In this study, we undertook an extensive investigation of groundwater in Bwaise slum, Kampala Uganda to understand the distribution and fate of sanitation-related nutrients N and P that are leached into groundwater. Transects of monitoring wells were installed in Bwaise slum and downstream of the slum. From these wells, water levels were measured and water quality analyses done to understand the distribution and composition of the nutrients, how they evolve downstream and the possible subsurface processes affecting their fate during transport. These findings are necessary to evaluate the risk of eutrophication posed by unsewered areas in urban cities and to design/implement sanitation systems that will effectively reduce the enrichment of these nutrients in groundwater. Key words: fate, groundwater, nutrients, processes, slums

Efficient Bayesian experimental design for contaminant source identification

Science.gov (United States)

Zhang, Jiangjiang; Zeng, Lingzao; Chen, Cheng; Chen, Dingjiang; Wu, Laosheng

2015-01-01

In this study, an efficient full Bayesian approach is developed for the optimal sampling well location design and source parameters identification of groundwater contaminants. An information measure, i.e., the relative entropy, is employed to quantify the information gain from concentration measurements in identifying unknown parameters. In this approach, the sampling locations that give the maximum expected relative entropy are selected as the optimal design. After the sampling locations are determined, a Bayesian approach based on Markov Chain Monte Carlo (MCMC) is used to estimate unknown parameters. In both the design and estimation, the contaminant transport equation is required to be solved many times to evaluate the likelihood. To reduce the computational burden, an interpolation method based on the adaptive sparse grid is utilized to construct a surrogate for the contaminant transport equation. The approximated likelihood can be evaluated directly from the surrogate, which greatly accelerates the design and estimation process. The accuracy and efficiency of our approach are demonstrated through numerical case studies. It is shown that the methods can be used to assist in both single sampling location and monitoring network design for contaminant source identifications in groundwater.

Development of a biotreatment system for the remediation of groundwater contaminated with hydrocarbons and trichloroethylene

International Nuclear Information System (INIS)

Folsom, B.R.; Kurisko, P.R.; Ensley, B.D.

1992-01-01

Inadvertent release of fuels and solvents into soil has resulted in groundwater contamination across the United States. This paper reports on the development of biologically based systems for treating mixtures of chemical contaminants which often requires knowledge of both degradative pathways and interactions between individual chemicals. These issues may necessitate the use of specialized microorganisms and/or treatment systems designed to overcome these limitations. One strategy for the treatment of chemical mixtures which cannot be source separated, such as contaminated groundwater, is a modular system to sequentially biodegrade groups of compatible chemicals. A two-stage bioreactor system was constructed for the treatment of groundwater contaminated with benzene and TCE. This treatment system is undergoing development for a field pilot demonstration. Successful implementation of this system should result in significant cost and time savings compared to competitive technologies

Groundwater Pollution Sources Apportionment in the Ghaen Plain, Iran

OpenAIRE

Mohammad Reza Vesali Naseh; Roohollah Noori; Ronny Berndtsson; Jan Adamowski; Elaheh Sadatipour

2018-01-01

Although Iran’s Ghaen Plain provides saffron to much of the world, no regional groundwater quality (GQ) assessment has yet been undertaken. Given the region’s potential for saltwater intrusion and heavy metal contamination, it is important to assess the GQ and determine its main probable source of pollution (MPSP). Such knowledge would allow for informed mitigation or elimination of the potential adverse health effects of this groundwater through its use as drinking water, or indirectly as a ...

Spatial control of groundwater contamination, using principal

Indian Academy of Sciences (India)

Spatial control of groundwater contamination, using principal component analysis ... anthropogenic (agricultural activities and domestic wastewaters), and marine ... The PC scores reflect the change of groundwater quality of geogenic origin ...

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

Science.gov (United States)

Zhang, Ping; Wu, Linwei; Rocha, Andrea M.; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D.; Wu, Liyou; Watson, David B.; Adams, Michael W. W.; Alm, Eric J.; Adams, Paul D.; Arkin, Adam P.

2018-01-01

ABSTRACT Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly (P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. PMID:29463661

Data Assimilation for Management of Industrial Groundwater Contamination at a Regional Scale

KAUST Repository

El Gharamti, Mohamad

2014-12-01

Groundwater is one of the main sources for drinking water and agricultural activities. Various activities of both humans and nature may lead to groundwater pollution. Very often, pollution, or contamination, of groundwater goes undetected for long periods of time until it begins to a ect human health and/or the environment. Cleanup technologies used to remediate pollution can be costly and remediation processes are often protracted. A more practical and feasible way to manage groundwater contamination is to monitor and predict contamination and act as soon as there is risk to the population and the environment. Predicting groundwater contamination requires advanced numerical models of groundwater ow and solute transport. Such numerical modeling is increasingly becoming a reference criterion for water resources assessment and environmental protection. Subsurface numerical models are, however, subject to many sources of uncertainties from unknown parameters and approximate dynamics. This dissertation considers the sequential data assimilation approach and tackles the groundwater contamination problem at the port of Rotterdam in the Netherlands. Industrial concentration data are used to monitor and predict the fate of organic contaminants using a threedimensional coupled ow and reactive transport model. We propose a number of 5 novel assimilation techniques that address di erent challenges, including prohibitive computational burden, the nonlinearity and coupling of the subsurface dynamics, and the structural and parametric uncertainties. We also investigate the problem of optimal observational designs to optimize the location and the number of wells. The proposed new methods are based on the ensemble Kalman Filter (EnKF), which provides an e cient numerical solution to the Bayesian ltering problem. The dissertation rst investigates in depth the popular joint and dual ltering formulations of the state-parameters estimation problem. New methodologies, algorithmically

Characteristics and factors of groundwater contamination in Asian coastal megacities

Science.gov (United States)

Saito, M.; Onodera, S. I.; Jin, G.; Shimizu, Y.; Admajaya, F. T.

2017-12-01

For the sustainable use of groundwater resources for the future, it is important to conserve its quality as well as quantity. Especially in the developing megacities, land subsidence and groundwater pollution by several contaminants (e.g. nitrogen, trace metals and organic pollutants etc.) is one of a critical environmental problems, because of the intensive extraction of groundwater and huge amount of contaminant load derived from domestic wastewater as well as agricultural and industrial wastewater. However, the process of groundwater degradation, including depletion and contamination with urbanization, has not been examined well in the previous studies. In the present study, we aim to confirm the characteristics and factors of groundwater contamination in coastal Asian megacities such as Osaka and Jakarta. In Osaka, groundwater was used as a water resource during the period of rapid population increase before 1970, and consequently groundwater resources have been degraded. Hydraulic potential of groundwater has been recovered after the regulation for abstraction. However, it is still below sea level in the deeper aquifer (>20 m) of some regions, and higher Cl-, NH4+-N and PO43-P concentrations were detected in these regions. The results also suggest that shallower aquifer (>10 m) is influenced by infiltration of sewage to groundwater. In the Jakarta metropolitan area, current hydraulic potential is below sea level in because of prior excess abstraction of groundwater. As a result, the direction of groundwater flow is now downward in the coastal area. The distribution of Cl- and Mn concentration in groundwater suggests that the decline in hydraulic potential has caused the intrusion of seawater and shallow groundwater into deep groundwater. It implies an accumulation of contaminants in deep aquifers. On the other hands, NO3-N in groundwater is suggested to be attenuated by the processes of denitrification and dilution in the coastal area.

Vulnerability of deep groundwater in the Bengal Aquifer System to contamination by arsenic

Science.gov (United States)

Burgess, W.G.; Hoque, M.A.; Michael, H.A.; Voss, C.I.; Breit, G.N.; Ahmed, K.M.

2010-01-01

Shallow groundwater, the primary water source in the Bengal Basin, contains up to 100 times the World Health Organization (WHO) drinking-water guideline of 10g l 1 arsenic (As), threatening the health of 70 million people. Groundwater from a depth greater than 150m, which almost uniformly meets the WHO guideline, has become the preferred alternative source. The vulnerability of deep wells to contamination by As is governed by the geometry of induced groundwater flow paths and the geochemical conditions encountered between the shallow and deep regions of the aquifer. Stratification of flow separates deep groundwater from shallow sources of As in some areas. Oxidized sediments also protect deep groundwater through the ability of ferric oxyhydroxides to adsorb As. Basin-scale groundwater flow modelling suggests that, over large regions, deep hand-pumped wells for domestic supply may be secure against As invasion for hundreds of years. By contrast, widespread deep irrigation pumping might effectively eliminate deep groundwater as an As-free resource within decades. Finer-scale models, incorporating spatial heterogeneity, are needed to investigate the security of deep municipal abstraction at specific urban locations. ?? 2010 Macmillan Publishers Limited. All rights reserved.

ASSESSMENT OF GROUNDWATER CONTAMINATION AROUND RECLAIMED MUNICIPAL LANDFILL – OTWOCK AREA, POLAND

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Dorota Porowska

2014-10-01

Full Text Available The research was conducted around reclaimed landfill, located on the suburb of Otwock, around 25 km south-west of Warsaw. The objective of this study was to identify the chemical composition of groundwater and to determine the landfill impact on the chemical composition of groundwater downgrading from the landfill. Otwock landfill is located in very permeable area, where leachate quickly seeps into groundwater and plays a key role in controlling redox condition (and chemical composition of groundwater of the downgradient area. High concentrations of HCO3-, Cl-, Ca2+, Mg2+, Na+, K+, Fetot. as well as DOC in groundwater downgradient from the landfill (in comparison to background water likely indicate that groundwater quality is being significantly affected by leachate percolation. Currently, the load of contamination is released from landfill periodically and slowly moves (70 m/y in the aquifer along the flow direction. The effect of distance of the piezometer from the pollution source was also investigated. As expected, water from the nearest piezometer to the landfill showed the highest values of contaminant (water temperature, specific electrical conductivity, sodium, iron, chlorides (except for summer and autumn analysis and calcium (except for winter analysis. Chemical status of groundwater downgradient from the landfill is poor.

Arsenic Contaminated Groundwater and Its Treatment Options in Bangladesh

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Sayedur Rahman Chowdhury

2012-12-01

Full Text Available Arsenic (As causes health concerns due to its significant toxicity and worldwide presence in drinking water and groundwater. The major sources of As pollution may be natural process such as dissolution of As-containing minerals and anthropogenic activities such as percolation of water from mines, etc. The maximum contaminant level for total As in potable water has been established as 10 µg/L. Among the countries facing As contamination problems, Bangladesh is the most affected. Up to 77 million people in Bangladesh have been exposed to toxic levels of arsenic from drinking water. Therefore, it has become an urgent need to provide As-free drinking water in rural households throughout Bangladesh. This paper provides a comprehensive overview on the recent data on arsenic contamination status, its sources and reasons of mobilization and the exposure pathways in Bangladesh. Very little literature has focused on the removal of As from groundwaters in developing countries and thus this paper aims to review the As removal technologies and be a useful resource for researchers or policy makers to help identify and investigate useful treatment options. While a number of technological developments in arsenic removal have taken place, we must consider variations in sources and quality characteristics of As polluted water and differences in the socio-economic and literacy conditions of people, and then aim at improving effectiveness in arsenic removal, reducing the cost of the system, making the technology user friendly, overcoming maintenance problems and resolving sludge management issues.

Identifying sources of groundwater nitrate contamination in a large alluvial groundwater basin with highly diversified intensive agricultural production

Science.gov (United States)

Lockhart, K. M.; King, A. M.; Harter, T.

2013-08-01

Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. The San Joaquin Valley, California, is an example of an agricultural landscape with a large diversity of field, vegetable, tree, nut, and citrus crops, but also confined animal feeding operations (CAFOs, here mostly dairies) that generate, store, and land apply large amounts of liquid manure. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (≤ 150 m deep), of which many have been affected by nitrate. Variability in crops, soil type, and depth to groundwater contribute to large variability in nitrate occurrence across the underlying aquifer system. The role of these factors in controlling groundwater nitrate contamination levels is examined. Two hundred domestic wells were sampled in two sub-regions of the San Joaquin Valley, Stanislaus and Merced (Stan/Mer) and Tulare and Kings (Tul/Kings) Counties. Forty six percent of well water samples in Tul/Kings and 42% of well water samples in Stan/Mer exceeded the MCL for nitrate (10 mg/L NO3-N). For statistical analysis of nitrate contamination, 78 crop and landuse types were considered by grouping them into ten categories (CAFO, citrus, deciduous fruits and nuts, field crops, forage, native, pasture, truck crops, urban, and vineyards). Vadose zone thickness, soil type, well construction information, well proximity to dairies, and dominant landuse near the well were considered. In the Stan/Mer area, elevated nitrate levels in domestic wells most strongly correlate with the combination of very shallow (≤ 21 m) water table and the presence of either CAFO derived animal waste applications or deciduous fruit and nut crops (synthetic fertilizer applications). In Tulare County, statistical data indicate that elevated

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

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Zhili He

2018-02-01

Full Text Available Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN, representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5 increased significantly (P < 0.05 as uranium or nitrate increased, and their changes could be used to successfully predict uranium and nitrate contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning.

Fluoride contamination in groundwater resources of Alleppey, southern India

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Dhanya Raj

2017-01-01

Full Text Available Alleppey is one of the thickly populated coastal towns of the Kerala state in southern India. Groundwater is the main source of drinking water for the 240,991 people living in this region. The groundwater is being extracted from a multi-layer aquifer system of unconsolidated to semi-consolidated sedimentary formations, which range in age from Recent to Tertiary. The public water distribution system uses dug and tube wells. Though there were reports on fluoride contamination, this study reports for the first time excess fluoride and excess salinity in the drinking water of the region. The quality parameters, like Electrical Conductivity (EC ranges from 266 to 3900 μs/cm, the fluoride content ranges from 0.68 to 2.88 mg/L, and the chloride ranges between the 5.7 to 1253 mg/L. The main water types are Na-HCO3, Na-CO3 and Na-Cl. The aqueous concentrations of F− and CO32− show positive correlation whereas F− and Ca2+ show negative correlation. The source of fluoride in the groundwater could be from dissolution of fluorapatite, which is a common mineral in the Tertiary sediments of the area. Long residence time, sediment–groundwater interaction and facies changes (Ca-HCO3 to Na-HCO3 during groundwater flow regime are the major factors responsible for the high fluoride content in the groundwater of the area. High strontium content and high EC in some of the wells indicate saline water intrusion that could be due to the excess pumping from the deeper aquifers of the area. The water quality index computation has revealed that 62% of groundwater belongs to poor quality and is not suitable for domestic purposes as per BIS and WHO standards. Since the groundwater is the only source of drinking water in the area, proper treatment strategies and regulating the groundwater extraction are required as the quality deterioration poses serious threat to human health.

Prediction of contamination potential of groundwater arsenic in Cambodia, Laos, and Thailand using artificial neural network

Science.gov (United States)

The arsenic (As) contamination of groundwater has increasingly been recognized as a major global issue of concern. As groundwater resources are one of most important freshwater sources for water supplies in Southeast Asian countries, it is important to investigate the spatial distribution of As cont...

Predicting geogenic arsenic contamination in shallow groundwater of south Louisiana, United States.

Science.gov (United States)

Yang, Ningfang; Winkel, Lenny H E; Johannesson, Karen H

2014-05-20

Groundwater contaminated with arsenic (As) threatens the health of more than 140 million people worldwide. Previous studies indicate that geology and sedimentary depositional environments are important factors controlling groundwater As contamination. The Mississippi River delta has broadly similar geology and sedimentary depositional environments to the large deltas in South and Southeast Asia, which are severely affected by geogenic As contamination and therefore may also be vulnerable to groundwater As contamination. In this study, logistic regression is used to develop a probability model based on surface hydrology, soil properties, geology, and sedimentary depositional environments. The model is calibrated using 3286 aggregated and binary-coded groundwater As concentration measurements from Bangladesh and verified using 78 As measurements from south Louisiana. The model's predictions are in good agreement with the known spatial distribution of groundwater As contamination of Bangladesh, and the predictions also indicate high risk of As contamination in shallow groundwater from Holocene sediments of south Louisiana. Furthermore, the model correctly predicted 79% of the existing shallow groundwater As measurements in the study region, indicating good performance of the model in predicting groundwater As contamination in shallow aquifers of south Louisiana.

Source Reduction Effectiveness at Fuel Contaminated Sites, Technical Summary Report

National Research Council Canada - National Science Library

2000-01-01

This report assesses the degree to which various types or engineered source-reduction efforts at selected fuel-contaminated sites have resulted in decreasing concentrations of fuel constituents dissolved in groundwater...

Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA

Science.gov (United States)

Smith, Richard L.; Repert, Deborah A.; Barber, Larry B.; LeBlanc, Denis R.

2013-01-01

The consequences of groundwater contamination can remain long after a contaminant source has been removed. Documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and associated geochemical changes are generally lacking. This study characterized the long-term natural attenuation of a groundwater contaminant plume in a sand and gravel aquifer on Cape Cod, Massachusetts, after the removal of the treated-wastewater source. Although concentrations of dissolved organic carbon (DOC) and other soluble constituents have decreased substantially in the 15 years since the source was removed, the core of the plume remains anoxic and has sharp redox gradients and elevated concentrations of nitrate and ammonium. Aquifer sediment was collected from near the former disposal site at several points in time and space along a 0.5-km-long transect extending downgradient from the disposal site and analyses of the sediment was correlated with changes in plume composition. Total sediment carbon content was generally low (rates in laboratory incubations, which ranged from 11.6 to 44.7 nmol (g dry wt)− 1 day− 1. Total water extractable organic carbon was groundwater velocity. This suggests that the total sorbed carbon pool is large relative to the rate of oxygen entrainment and will be impacting groundwater geochemistry for many decades. This has implications for long-term oxidation of reduced constituents, such as ammonium, that are being transported downgradient away from the infiltration beds toward surface and coastal discharge zones.

Arsenic levels in the groundwater of Korea and the urinary excretion among contaminated area.

Science.gov (United States)

Park, Jung-Duck; Choi, Seong-Jin; Choi, Byung-Sun; Lee, Choong-Ryeol; Kim, Heon; Kim, Yong-Dae; Park, Kyung-Soo; Lee, Young-Jo; Kang, Seojin; Lim, Kyung-Min; Chung, Jin-Ho

2016-09-01

Drinking water is a main source of human exposure to arsenic. Hence, the determination of arsenic in groundwater is essential to assess its impact on public health. Here, we report arsenic levels in the groundwater of 722 sites covering all six major provinces of Korea. Water was sampled in two occasions (summer, 722 sites and winter, 636 sites) and the arsenic levels were measured with highly sensitive inductively coupled plasma-mass spectrometry method (limit of detection, 0.1 μg/l) to encompass the current drinking water standard (arsenic in groundwater ranged from 0.1 to 48.4 μg/l. A 88.0-89.0% of sites were 10 μg/l. Notably, urinary arsenic excretion of people around these regions was markedly higher compared with non-contaminated areas (arsenic-contaminated groundwater may contribute to its systemic exposure.

Conceptual Models for Migration of Key Groundwater Contaminants Through the Vadose Zone and Into the Upper Unconfined Aquifer Below the B-Complex

Energy Technology Data Exchange (ETDEWEB)

Serne, R. Jeffrey; Bjornstad, Bruce N.; Keller, Jason M.; Thorne, Paul D.; Lanigan, David C.; Christensen, J. N.; Thomas, Gregory S.

2010-07-01

The B-Complex contains 3 major crib and trench disposal sites and 3 SST farms that have released nearly 346 mega-liters of waste liquids containing the following high groundwater risk drivers: ~14,000 kg of CN, 29,000 kg of Cr, 12,000 kg of U and 145 Ci of Tc-99. After a thorough review of available vadose zone sediment and pore water, groundwater plume, field gamma logging, field electrical resistivity studies, we developed conceptual models for which facilities have been the significant sources of the contaminants in the groundwater and estimated the masses of these contaminants remaining in the vadose zone and currently present in the groundwater in comparison to the totals released. This allowed us to make mass balance calculations on how consistent our knowledge is on the current deep vadose zone and groundwater distribution of contaminants. Strengths and weaknesses of the conceptual models are discussed as well as implications on future groundwater and deep vadose zone remediation alternatives. Our hypothesized conceptual models attribute the source of all of the cyanide and most of the Tc-99 currently in the groundwater to the BY cribs. The source of the uranium is the BX-102 tank overfill event and the source of most of the chromium is the B-7-A&B and B-8 cribs. Our mass balance estimates suggest that there are much larger masses of U, CN, and Tc remaining in the deep vadose zone within ~20 ft of the water table than is currently in the groundwater plumes below the B-Complex. This hypothesis needs to be carefully considered before future remediation efforts are chosen. The masses of these groundwater risk drivers in the the groundwater plumes have been increasing over the last decade and the groundwater plumes are migrating to the northwest towards the Gable Gap. The groundwater flow rate appears to flucuate in response to seasonal changes in hydraulic gradient. The flux of contaminants out of the deep vadose zone from the three proposed sources also

Potential for saturated ground-water system contamination at the Lawrence Livermore National Laboratory

International Nuclear Information System (INIS)

Stone, R.; Ruggieri, M.R.; Rogers, L.L.; Emerson, D.O.; Buddemeier, R.W.

1982-01-01

A program of hydrogeologic investigation has been carried out to determine the likelihood of contaminant movement to the saturated zone from near the ground surface at Lawrence Livermore National Laboratory (LLNL). A companion survey of potential contaminant sources was also conducted at the LLNL. Water samples from selected LLNL wells were analyzed to test the water quality in the uppermost part of the saturated zone, which is from 14 to 48 m (45 to 158 ft) beneath the surface. Only nitrate and tritium were found in concentrations above natural background. In one well, the nitrate was slightly more concentrated than the drinking water limit. The nitrate source has not been found. The tritium in all ground-water samples from wells was found far less concentrated than the drinking water limit. The extent of infiltration of surface water was traced with environmental tritium. The thickness and stratigraphy of the unsaturated zone beneath the LLNL, and nearby area, was determined with specially constructed wells and boreholes. Well hydrograph analysis indicated where infiltration of surface water reached the saturated ground-water system. The investigation indicates that water infiltrating from the surface, through alluvial deposits, reaches the saturated zone along the course of Arroyo Seco, Arroyo Las Positas, and from the depression near the center of the site where seasonal water accumulates. Several potential contaminant sources were identified, and it is likely that contaminants could move from near the ground surface to the saturated zone beneath LLNL. Additional ground-water sampling and analysis will be performed and ongoing investigations will provide estimates of the speed with which potential contaminants can flow laterally in the saturated zone beneath LLNL. 34 references, 61 figures, 16 tables

Association of leukemia with radium groundwater contamination

International Nuclear Information System (INIS)

Lyman, G.H.; Lyman, C.G.; Johnson, W.

1985-01-01

Radiation exposure, including the ingestion of radium, has been causally associated with leukemia in man. Groundwater samples from 27 counties on or near Florida phosphate lands were found to exceed 5 pCi/L total radium in 12.4% of measurements. The incidence of leukemia was greater in those counties with high levels of radium contamination (greater than 10% of the samples contaminated) than in those with low levels of contamination. Rank correlation coefficients of .56 and .45 were observed between the radium contamination level and the incidence of total leukemia and acute myeloid leukemia, respectively. The standardized incidence density ratio for those in high-contamination counties was 1.5 for total leukemia and 2.0 for acute myeloid leukemia. Further investigation is necessary, however, before a causal relationship between groundwater radium content and human leukemia can be established

Determination of timescales of nitrate contamination by groundwater age models in a complex aquifer system

Science.gov (United States)

Koh, E. H.; Lee, E.; Kaown, D.; Lee, K. K.; Green, C. T.

2017-12-01

Timing and magnitudes of nitrate contamination are determined by various factors like contaminant loading, recharge characteristics and geologic system. Information of an elapsed time since recharged water traveling to a certain outlet location, which is defined as groundwater age, can provide indirect interpretation related to the hydrologic characteristics of the aquifer system. There are three major methods (apparent ages, lumped parameter model, and numerical model) to date groundwater ages, which differently characterize groundwater mixing resulted by various groundwater flow pathways in a heterogeneous aquifer system. Therefore, in this study, we compared the three age models in a complex aquifer system by using observed age tracer data and reconstructed history of nitrate contamination by long-term source loading. The 3H-3He and CFC-12 apparent ages, which did not consider the groundwater mixing, estimated the most delayed response time and a highest period of the nitrate loading had not reached yet. However, the lumped parameter model could generate more recent loading response than the apparent ages and the peak loading period influenced the water quality. The numerical model could delineate various groundwater mixing components and its different impacts on nitrate dynamics in the complex aquifer system. The different age estimation methods lead to variations in the estimated contaminant loading history, in which the discrepancy in the age estimation was dominantly observed in the complex aquifer system.

On the use of coprostanol to identify source of nitrate pollution in groundwater

Science.gov (United States)

Nakagawa, Kei; Amano, Hiroki; Takao, Yuji; Hosono, Takahiro; Berndtsson, Ronny

2017-07-01

Investigation of contaminant sources is indispensable for developing effective countermeasures against nitrate (NO3-) pollution in groundwater. Known major nitrogen (N) sources are chemical fertilizers, livestock waste, and domestic wastewater. In general, scatter diagrams of δ18O and δ15N from NO3- can be used to identify these pollution sources. However, this method can be difficult to use for chemical fertilizers and livestock waste sources due to the overlap of δ18O and δ15N ranges. In this study, we propose to use coprostanol as an indicator for the source of pollution. Coprostanol can be used as a fecal contamination indicator because it is a major fecal sterol formed by the conversion of cholesterol by intestinal bacteria in the gut of higher animals. The proposed method was applied to investigate NO3- pollution sources for groundwater in Shimabara, Nagasaki, Japan. Groundwater samples were collected at 33 locations from March 2013 to November 2015. These data were used to quantify relationships between NO3-N, δ15N-NO3-, δ18O-NO3-, and coprostanol. The results show that coprostanol has a potential for source identification of nitrate pollution. For lower coprostanol concentrations (conventional diagrams of isotopic ratios cannot distinguish pollution sources, coprostanol may be a useful tool.

In situ remediation of uranium contaminated groundwater

International Nuclear Information System (INIS)

Dwyer, B.P.; Marozas, D.C.

1997-01-01

In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and laboratory and field results are discussed with regard to other potential contaminated groundwater treatment applications

Determination of dominant sources of nitrate contamination in transboundary (Russian Federation/Ukraine) catchment with heterogeneous land use.

Science.gov (United States)

Vystavna, Y; Diadin, D; Grynenko, V; Yakovlev, V; Vergeles, Y; Huneau, F; Rossi, P M; Hejzlar, J; Knöller, K

2017-09-18

Nitrate contamination of surface water and shallow groundwater was studied in transboundary (Russia/Ukraine) catchment with heterogeneous land use. Dominant sources of nitrate contamination were determined by applying a dual δ 15 N-NO 3 and δ 18 O-NO 3 isotope approach, multivariate statistics, and land use analysis. Nitrate concentration was highly variable from 0.25 to 22 mg L -1 in surface water and from 0.5 to 100 mg L -1 in groundwater. The applied method indicated that sewage to surface water and sewage and manure to groundwater were dominant sources of nitrate contamination. Nitrate/chloride molar ratio was added to support the dual isotope signature and indicated the contribution of fertilizers to the nitrate content in groundwater. Groundwater temperature was found to be an additional indicator of manure and sewerage leaks in the shallow aquifer which has limited protection and is vulnerable to groundwater pollution.

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Version 2.0 theory and user's manual

International Nuclear Information System (INIS)

Rood, A.S.

1993-06-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track I and Track II assessment of CERCLA (Comprehensive Environmental Response, Compensation and Liability Act) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1992). The code calculates the limiting soil concentration such that, after leaching and transport to the aquifer, regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation in groundwater. In Version 2.0, GWSCREEN has incorporated an additional source model to calculate the impacts to groundwater resulting from the release to percolation ponds. In addition, transport of radioactive progeny has also been incorporated. GWSCREEN has shown comparable results when compared against other codes using similar algorithms and techniques. This code was designed for assessment and screening of the groundwater pathway when field data is limited. It was not intended to be a predictive tool

Bacterial Community Dynamics in Dichloromethane-Contaminated Groundwater Undergoing Natural Attenuation

Directory of Open Access Journals (Sweden)

Justin Wright

2017-11-01

Full Text Available The uncontrolled release of the industrial solvent methylene chloride, also known as dichloromethane (DCM, has resulted in widespread groundwater contamination in the United States. Here we investigate the role of groundwater bacterial communities in the natural attenuation of DCM at an undisclosed manufacturing site in New Jersey. This study investigates the bacterial community structure of groundwater samples differentially contaminated with DCM to better understand the biodegradation potential of these autochthonous bacterial communities. Bacterial community analysis was completed using high-throughput sequencing of the 16S rRNA gene of groundwater samples (n = 26 with DCM contamination ranging from 0.89 to 9,800,000 μg/L. Significant DCM concentration-driven shifts in overall bacterial community structure were identified between samples, including an increase in the abundance of Firmicutes within the most contaminated samples. Across all samples, a total of 6,134 unique operational taxonomic units (OTUs were identified, with 16 taxa having strong correlations with increased DCM concentration. Putative DCM degraders such as Pseudomonas, Dehalobacterium and Desulfovibrio were present within groundwater across all levels of DCM contamination. Interestingly, each of these taxa dominated specific DCM contamination ranges respectively. Potential DCM degrading lineages yet to be cited specifically as a DCM degrading organisms, such as the Desulfosporosinus, thrived within the most heavily contaminated groundwater samples. Co-occurrence network analysis revealed aerobic and anaerobic bacterial taxa with DCM-degrading potential were present at the study site. Our 16S rRNA gene survey serves as the first in situ bacterial community assessment of contaminated groundwater harboring DCM concentrations ranging over seven orders of magnitude. Diversity analyses revealed known as well as potentially novel DCM degrading taxa within defined DCM concentration

Depth Stratification Leads to Distinct Zones of Manganese and Arsenic Contaminated Groundwater.

Science.gov (United States)

Ying, Samantha C; Schaefer, Michael V; Cock-Esteb, Alicea; Li, Jun; Fendorf, Scott

2017-08-15

Providing access to safe drinking water is a global challenge, for which groundwater is increasingly being used throughout the world. However, geogenic contaminants limit the suitability of groundwater for domestic purposes over large geographic areas across most continents. Geogenic contaminants in groundwater are often evaluated individually, but here we demonstrate the need to evaluate multiple contaminants to ensure that groundwater is safe for human consumption and agricultural usage. We compiled groundwater chemical data from three aquifer regions across the world that have been reported to have widespread As and Mn contamination including the Glacial Aquifer in the U.S., the Ganges-Brahmaputra-Mehta Basin within Bangladesh, and the Mekong Delta in Cambodia, along with newly sampled wells in the Yangtze River Basin of China. The proportion of contaminated wells increase by up to 40% in some cases when both As and Mn contaminants are considered. Wilcoxon rank-sum analysis indicates that Mn contamination consistently occurs at significantly shallower depths than As contaminated wells in all regions. Arsenic concentrations in groundwater are well predicted by redox indicators (Eh and dissolved oxygen) whereas Mn shows no significant relationship with either parameter. These findings illustrate that the number of safe wells may be drastically overestimated in some regions when Mn contamination is not taken into account and that depth may be used as a distinguishing variable in efforts to predict the presence of groundwater contaminants regionally.

Effect of land use and urbanization on hydrochemistry and contamination of groundwater from Taejon area, Korea

Science.gov (United States)

Jeong, Chan Ho

2001-11-01

Taejon Metropolitan City located in the central part of South Korea has grown and urbanized rapidly. The city depends heavily on groundwater as a water resource. Because of ubiquitous pollution sources, the quality and contamination have become important issues for the urban groundwater supply. This study has investigated the chemical characteristics and the contamination of groundwater in relation to land use. An attempt was made to distinguish anthrophogenic inputs from the influence of natural chemical weathering on the chemical composition of groundwater at Taejon. Groundwater samples collected at 170 locations in the Taejon area show very variable chemical composition of groundwater, e.g. electrical conductance ranges from 65 to 1,290 μS/cm. Most groundwater is weakly acidic and the groundwater chemistry is more influenced by land use and urbanization than by aquifer rock type. Most groundwater from green areas and new town residential districts has low electrical conductance, and is of Ca-HCO3 type, whereas the chemical composition of groundwater from the old downtown and industrial district is shifted towards a Ca-Cl (NO3+SO4) type with high electrical conductance. A number of groundwater samples in the urbanized area are contaminated by high nitrate and chlorine, and exhibit high hardness. The EpCO2, that is the CO2 content of a water sample relative to pure water, was computed to obtain more insight into the origin of CO2 and bicarbonate in the groundwater. The CO2 concentration of groundwater in the urbanized area shows a rough positive relationship with the concentration of major inorganic components. The sources of nitrate, chlorine and excess CO2 in the groundwater are likely to be municipal wastes of unlined landfill sites, leaky latrines and sewage lines. Chemical data of commercial mineral water from other Jurassic granite areas were compared to the chemical composition of the groundwater in the Taejon area. Factor analysis of the chemical data

Development and application of a novel method for regional assessment of groundwater contamination risk in the Songhua River Basin.

Science.gov (United States)

Nixdorf, Erik; Sun, Yuanyuan; Lin, Mao; Kolditz, Olaf

2017-12-15

The main objective of this study is to quantify the groundwater contamination risk of Songhua River Basin by applying a novel approach of integrating public datasets, web services and numerical modelling techniques. To our knowledge, this study is the first to establish groundwater risk maps for the entire Songhua River Basin, one of the largest and most contamination-endangered river basins in China. Index-based groundwater risk maps were created with GIS tools at a spatial resolution of 30arc sec by combining the results of groundwater vulnerability and hazard assessment. Groundwater vulnerability was evaluated using the DRASTIC index method based on public datasets at the highest available resolution in combination with numerical groundwater modelling. As a novel approach to overcome data scarcity at large scales, a web mapping service based data query was applied to obtain an inventory for potential hazardous sites within the basin. The groundwater risk assessment demonstrated that contamination risk. These areas were mainly located in the vast plain areas with hotspots particularly in the Changchun metropolitan area. Moreover, groundwater levels and pollution point sources were found to play a significantly larger impact in assessing these areas than originally assumed by the index scheme. Moderate contamination risk was assigned to 27% of the aquifers, predominantly associated with less densely populated agricultural areas. However, the majority of aquifer area in the sparsely populated mountain ranges displayed low groundwater contamination risk. Sensitivity analysis demonstrated that this novel method is valid for regional assessments of groundwater contamination risk. Despite limitations in resolution and input data consistency, the obtained groundwater contamination risk maps will be beneficial for regional and local decision-making processes with regard to groundwater protection measures, particularly if other data availability is limited. Copyright �

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning.

Science.gov (United States)

He, Zhili; Zhang, Ping; Wu, Linwei; Rocha, Andrea M; Tu, Qichao; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D; Wu, Liyou; Yang, Yunfeng; Elias, Dwayne A; Watson, David B; Adams, Michael W W; Fields, Matthew W; Alm, Eric J; Hazen, Terry C; Adams, Paul D; Arkin, Adam P; Zhou, Jizhong

2018-02-20

Contamination from anthropogenic activities has significantly impacted Earth's biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly ( P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. IMPORTANCE Disentangling the relationships between biodiversity and ecosystem functioning is an important but poorly understood topic in ecology. Predicting ecosystem functioning on the basis of biodiversity is even more difficult, particularly with microbial biomarkers. As an exploratory effort, this study used key microbial functional genes as biomarkers to provide predictive understanding of environmental contamination and ecosystem functioning. The results indicated that the overall functional gene richness/diversity decreased as uranium increased in groundwater, while specific key microbial guilds increased significantly as

Assessment of emerging groundwater contaminants

OpenAIRE

Stuart, Marianne; Lapworth, Dan; Manamsa, Katya; Crane, Emily; White, Debbie

2016-01-01

Emerging contaminants in groundwater are important. These have been studied at a range of scales. An increasing range of compounds is being detected Urban areas show impact of sewage and industrial wastewater. Some ECs are probably no threat to drinking water at such µg/L concentrations, e.g. caffeine Others may prove to be in the future. There is little information on their impact on other groundwater receptors in the environment. We are still far from understanding which of these comp...

Characterization of bacterial diversity in contaminated groundwater using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Science.gov (United States)

Martin, Misty S; Santos, Inês C; Carlton, Doug D; Stigler-Granados, Paula; Hildenbrand, Zacariah L; Schug, Kevin A

2018-05-01

Groundwater is a major source for drinking water in the United States, and therefore, its quality and quantity is of extreme importance. One major concern that has emerged is the possible contamination of groundwater due to the unconventional oil and gas extraction activities. As such, the impacts of exogenous contaminants on microbial ecology is an area to be explored to understand what are the chemical and physical conditions that allow the proliferation of pathogenic bacteria and to find alternatives for water treatment by identifying organic-degrading bacteria. In this work, we assess the interplay between groundwater quality and the microbiome in contaminated groundwaters rich in hydrocarbon gases, volatile organic and inorganic compounds, and various metals. Opportunistic pathogenic bacteria, such as Aeromonas hydrophila, Bacillus cereus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia, were identified, increasing the risk for consumption of and exposure to these contaminated groundwaters. Additionally, antimicrobial tests revealed that many of the identified bacteria were resistant to different antibiotics. The MALDI-TOF MS results were successfully confirmed with 16S rRNA gene sequencing, proving the accuracy of this high-throughput method. Collectively, these data provide a seminal understanding of the microbial populations in contaminated groundwater overlying anthropogenic activities like unconventional oil and gas development. Copyright © 2017 Elsevier B.V. All rights reserved.

A review of groundwater contamination near municipal solid waste landfill sites in China.

Science.gov (United States)

Han, Zhiyong; Ma, Haining; Shi, Guozhong; He, Li; Wei, Luoyu; Shi, Qingqing

2016-11-01

Landfills are the most widely used method for municipal solid waste (MSW) disposal method in China. However, these facilities have caused serious groundwater contamination due to the leakage of leachate. This study, analyzed 32 scientific papers, a field survey and an environmental assessment report related to groundwater contamination caused by landfills in China. The groundwater quality in the vicinity of landfills was assessed as "very bad" by a comprehensive score (FI) of 7.85 by the Grading Method in China. Variety of pollutants consisting of 96 groundwater pollutants, 3 organic matter indicators, 2 visual pollutants and 6 aggregative pollutants had been detected in the various studies. Twenty-two kinds of pollutants were considered to be dominant. According to the Kruskal-Wallis test and the median test, groundwater contamination differed significantly between regions in China, but there were no significant differences between dry season and wet season measurements, except for some pollutants in a few landfill sites. Generally, the groundwater contamination appeared in the initial landfill stage after five years and peaked some years afterward. In this stage, the Nemerow Index (PI) of groundwater increased exponentially as landfill age increased at some sites, but afterwards decreased exponentially with increasing age at others. After 25years, the groundwater contamination was very low at selected landfills. The PI values of landfills decreased exponentially as the pollutant migration distance increased. Therefore, the groundwater contamination mainly appeared within 1000m of a landfill and most of serious groundwater contamination occurred within 200m. The results not only indicate that the groundwater contamination near MSW landfills should be a concern, but also are valuable to remediate the groundwater contamination near MSW landfills and to prevent the MSW landfill from secondary pollutions, especially for developing countries considering the similar

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Version 2.0 theory and user`s manual

Energy Technology Data Exchange (ETDEWEB)

Rood, A.S.

1993-06-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track I and Track II assessment of CERCLA (Comprehensive Environmental Response, Compensation and Liability Act) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1992). The code calculates the limiting soil concentration such that, after leaching and transport to the aquifer, regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation in groundwater. In Version 2.0, GWSCREEN has incorporated an additional source model to calculate the impacts to groundwater resulting from the release to percolation ponds. In addition, transport of radioactive progeny has also been incorporated. GWSCREEN has shown comparable results when compared against other codes using similar algorithms and techniques. This code was designed for assessment and screening of the groundwater pathway when field data is limited. It was not intended to be a predictive tool.

Nuclear techniques to investigate source and origin of groundwater pollutants and their flow path at Indian Rare Earths Ltd., Cochin, Kerala

International Nuclear Information System (INIS)

Tirumalesh, K.; Shivanna, K.; Noble, J.

2007-01-01

Hydrochemical, environmental isotope and injected radiotracer investigations were carried out in order to investigate the possible source of contaminants and their movement in groundwater at Indian Rare Earths (IRE) site. Water samples were collected from piezometers, dug wells and river in and around IRE site for measurement of physical parameters, chemistry and isotopes. Chemical results show high fluoride, nitrate, sulphate and phosphate concentrations in piezometers whereas dug wells and river samples are free from contamination. Isotope data indicate that the contaminated groundwaters are enriched in δ 2 H and δ 18 O compared to dug well and river samples. Radiotracer experiments were carried out using single-well and multi-well techniques (radiotracers: 82 Br and 3 H) for determining groundwater filtration velocity and flow direction, respectively. Groundwater filtration velocity was found to be about 1.3 cm/day and flow direction is from south to north. Based on the investigations it can be concluded that groundwater is getting contamination from southern part of IRE campus and the possible source for these contaminants could be the Fertilizer and Chemical of Travancore (FACT) industry. (author)

A technical approach to groundwater contamination problems

International Nuclear Information System (INIS)

Burton, J.C.; Leser, C.; Rose, C.M.

1993-01-01

Argonne National Laboratory has been performing technical investigations at sites in Nebraska and Kansas that have identified groundwater contamination by carbon tetrachloride. This comprehensive program will ultimately provide the affected communities with safe drinking water. The first step in the program is to evaluate the available data and identify sites that will require an Alternate Water Supply Study (AWSS). The objective of the AWSS is to identify options for providing a safe drinking water supply to all users, in compliance with the Safe Drinking Water Act. The AWSS consists of an engineering and cost evaluation followed by implementation of the selected alternative. For sites with contamination less than a specific concentration, the AWSS is regarded as a satisfactory long term solution, and no further action is taken. For those sites with concentrations above that specific limit, the AWSS implementation is regarded as only a stopgap measure, and the site is selected for additional remedial action. The first step of the remedial action is an Expedited Site Characterization (ESC). The ESC was developed at Argonne to decrease the cost and time of the remedial investigation and feasibility study while producing a high-quality technical investigation. The ESC is designed to characterize the contaminant plume configuration and movement, which requires an understanding of the geological and hydrogeologic controls on groundwater movement as well as the nature and extent of any remaining carbon tetrachloride source in the soils. The ESC program uses a multidisciplinary technical approach that incorporates geology, geochemistry, geohydrology, and geophysics. Field activities include sampling, chemical analysis, and borehole and surface geophysical surveys

Bioremediation of Uranium-Contaminated Groundwater using Engineered Injection and Extraction

Science.gov (United States)

Greene, J. A.; Neupauer, R.; Ye, M.; Kasprzyk, J. R.; Mays, D. C.; Curtis, G. P.

2017-12-01

During in-situ remediation of contaminated groundwater, a treatment chemical is injected into the contaminated groundwater to react with and degrade the contaminant, with reactions occurring where the treatment chemical contacts the contaminant. Traditional in-situ groundwater remediation relies on background groundwater flow for spreading of treatment chemicals into contaminant plumes. Engineered Injection and Extraction (EIE), in which time-varying induced flow fields are used to actively spread the treatment chemical into the contaminant plume, has been developed to increase contact between the contaminant and treatment chemical, thereby enhancing contaminant degradation. EIE has been investigated for contaminants that degrade through irreversible bimolecular reaction with a treatment chemical, but has not been investigated for a contaminant governed by reversible reactions. Uranium primarily occurs in its aqueous, mobile form, U(VI), in the environment but can be bioreduced to its sparingly soluble, immobile form, U(IV), by iron reducing bacteria stimulated by an acetate amendment. In this study, we investigate the ability of EIE to facilitate and sustain favorable conditions to immobilize uranium during remediation, and to prevent re-mobilization of uranium into the aqueous phase after active remediation has ended. Simulations in this investigation are conducted using a semi-synthetic model based on physical and chemical conditions at the Naturita Uranium Mill Tailings Remedial Action (UMTRA) site in southwestern Colorado and the Old Rifle UMTRA site in western Colorado. The EIE design is optimized for the synthetic model using the Borg multi-objective evolutionary algorithm.

Isotope and chemical techniques in assessing groundwater contamination from Metro Manila landfill

International Nuclear Information System (INIS)

Castaneda, Soledad S.; Almoneda, Rosalina V.; Ascano, Luz; Del Castillo, Lorena A.; Fernandez, Lourdes G.; Sucgang, Raymond J.; Iblan, Cynthia L.; Baui, Daniel G.

2007-01-01

The first objective of the investigations is establishing benchmark isotopic characteristics of water sources and baseline concentrations of main environmental parameters related to contamination from the landfill. Water samples were collected from the production wells and surface water in the municipalities in proximity of the landfill, in Rodriguez and in San Mateo. Stable isotope characterization of the deep groundwater and rivers shows isotopic values clustering along the LMWL with ae 18 O ranging from -7.5 promille to -6.5 promille and ae 2 H ranging from - 53.59 promille to -42.91. The shallow groundwater are more isotopically enriched trending towards the evaporation line, with mean ae 18 O and aeD values of -6.46 promille and -44.14 promille, respectively. The mean isotopic signatures of surface water, with mean ae 18 O of -7.19 promille and deep groundwater, with mean ae 18 O of -6.67 promille, in Rodriguez are significantly distinct. San Mateo groundwater appear to be more isotopically enriched, indicating recharge different from that of Rodriguez groundwater. Leachate from the landfill exhibits a distinct isotopic composition from the freshwaters, with ae 18 O and aeD values of -5.58 promille and -31.66 promille. The significant differences in the isotopic signatures of the different water sources in the study area would facilitate detection of contamination from leachate run-off to the surface water, and eventually, to the groundwater. Trace metals in the water samples collected, generally, were below the regulatory limits for drinking water and surface water. Results of elemental determination in the sediment samples obtained from rivers showed that aside from the major crustal elements, Zn, Cu, and Ni were also present in significant amount. (author)

Occurrence, sources and fate of pharmaceuticals and personal care products in the groundwater: A review

Directory of Open Access Journals (Sweden)

Qian Sui

2015-11-01

Full Text Available The presence of pharmaceuticals and personal care products (PPCPs in the aquatic environment may pose potential threat to the ecosystem and human health, hence PPCPs have aroused much concern over the world. The contamination of PPCPs in the groundwater, the main source of drinking water supply in many countries and regions, has been extensively studied in the last decade. This paper reviews the occurrence of frequently detected PPCPs, including antibiotics, anti-inflammatories, lipid-regulators, carbamazepine, caffeine, and N,N-diethyl-m-toluamide in groundwater, with special concern to the progress made over the past three years. Possible emission sources for PPCPs in groundwater, such as wastewater and contaminated surface water, landfills, septic systems, livestock breeding and sewer leakage, are summarized. Besides, adsorption, migration and degradation, the dominant mechanisms in the subsurface transport and fate of PPCPs, are discussed, and the insights into the future study of PPCPs in the groundwater are provided.

Dilution and volatilization of groundwater contaminant discharges in streams

DEFF Research Database (Denmark)

Aisopou, Angeliki; Bjerg, Poul Løgstrup; Sonne, Anne Thobo

2015-01-01

measurement. The solution was successfully applied to published field data obtained in a large and a small Danish stream and provided valuable information on the risk posed by the groundwater contaminant plumes. The results provided by the dilution and volatilization model are very different to those obtained......An analytical solution to describe dilution and volatilization of a continuous groundwater contaminant plume into streams is developed for risk assessment. The location of groundwater plume discharge into the stream (discharge through the side versus bottom of the stream) and different...

Microbial Degradation of Phenols and Aromatic Hydrocarbons in Creosote-contaminated Groundwater Under Nitrate-reducing Conditions

DEFF Research Database (Denmark)

Flyvbjerg, John; Arvin, Erik; Jensen, Bjørn K.

1993-01-01

of toluene, 2,4-DMP, 3,4-DMP and p-cresol depended on nitrate or nitrite as electron acceptors. 40–80% of the nitrate consumed during degradation of the aromatic compounds was recovered as nitrite, and the consumption of nitrate was accompanied by a production of ATP. Stoichiometric calculations indicated......Batch experiments were carried out to investigate the biodegradation of phenols and aromatic hydrocarbons under anaerobic, nitrate-reducing conditions in groundwater from a creosote-contaminated site at Fredensborg, Denmark. The bacteria in the creosote-contaminated groundwater degraded a mixture...... that in addition to the phenols are toluene other carbon sources present in the groundwater contributed to the consumption of nitrate. If the groundwater was incubated under anaerobic conditions without nitrate, sulphate-reducing conditions evolved after ∼ 1 month at 20°C and ∼2 months at 10°C. In the sulphate...

Y-12 Groundwater Protection Program Extent Of The Primary Groundwater Contaminants At The Y-12 National Security Complex

Energy Technology Data Exchange (ETDEWEB)

None, None

2013-12-01

This report presents data summary tables and maps used to define and illustrate the approximate lateral extent of groundwater contamination at the U.S. Department of Energy (DOE) Y-12 National Security Complex (Y-12) in Oak Ridge, Tennessee. The data tables and maps address the primary (i.e., most widespread and mobile) organic, inorganic, and radiological contaminants in the groundwater. The sampling locations, calculated contaminant concentrations, plume boundary values, and paired map format used to define, quantify, delineate, and illustrate the approximate extent of the primary organic, inorganic, and radiological contaminants in groundwater at Y-12 are described.

Ground-water contamination at Wurtsmith Air Force Base, Michigan

Science.gov (United States)

Stark, J.R.; Cummings, T.R.; Twenter, F.R.

1983-01-01

A sand and gravel aquifer of glacial origin underlies Wurtsmith Air Force Base in northeastern lower Michigan. The aquifer overlies a thick clay layer at an average depth of 65 feet. The water table is about 10 feet below land surface in the western part of the Base and about 25 feet below land surface in the eastern part. A ground-water divide cuts diagonally across the Base from northwest to southeast. South of the divide, ground water flows to the Au Sable River; north of the divide, it flows to Van Etten Creek and Van Etten Lake. Mathematical models were used to aid in calculating rates of groundwater flow. Rates range from about 0.8 feet per day in the eastern part of the Base to about 0.3 feet per day in the western part. Models also were used as an aid in making decisions regarding purging of contaminated water from the aquifer. In 1977, trichloroethylene was detected in the Air Force Base water-supply system. It had leaked from a buried storage tank near Building 43 in the southeastern part of the Base and moved northeastward under the influence of the natural ground-water gradient and the pumping of Base water-supply wells. In the most highly contaminated part of the plume, concentrations are greater than 1,000 micrograms per liter. Current purge pumping is removing some of the trichloroethylene, and seems to have arrested its eastward movement. Pumping of additional purge wells could increase the rate of removal. Trichloroethylene has also been detected in ground water in the vicinity of the Base alert apron, where a plume from an unknown source extends northeastward off Base. A smaller, less well-defined area of contamination also occurs just north of the larger plume. Trichloroethylene, identified near the waste-treatment plant, seepage lagoons, and the northern landfill area, is related to activities and operations in these areas. Dichloroethylene and trichloroethylene occur in significant quantities westward of Building 43, upgradient from the major

Tracing freshwater nitrate sources in pre-alpine groundwater catchments using environmental tracers

Science.gov (United States)

Stoewer, M. M.; Knöller, K.; Stumpp, C.

2015-05-01

Groundwater is one of the main resources for drinking water. Its quality is still threatened by the widespread contaminant nitrate (NO3-). In order to manage groundwater resources in a sustainable manner, we need to find options of lowering nitrate input. Particularly, a comprehensive knowledge of nitrate sources is required in areas which are important current and future drinking water reservoirs such as pre-alpine aquifers covered with permanent grassland. The objective of the present study was to identify major sources of nitrate in groundwater with low mean nitrate concentrations (8 ± 2 mg/L). To achieve the objective, we used environmental tracer approaches in four pre-alpine groundwater catchments. The stable isotope composition and tritium content of water were used to study the hydrogeology and transit times. Furthermore, nitrate stable isotope methods were applied to trace nitrogen from its sources to groundwater. The results of the nitrate isotope analysis showed that groundwater nitrate was derived from nitrification of a variety of ammonium sources such as atmospheric deposition, mineral and organic fertilizers and soil organic matter. A direct influence of mineral fertilizer, atmospheric deposition and sewage was excluded. Since temporal variation in stable isotopes of nitrate were detected only in surface water and locally at one groundwater monitoring well, aquifers appeared to be well mixed and influenced by a continuous nitrate input mainly from soil derived nitrogen. Hydrogeological analysis supported that the investigated aquifers were less vulnerable to rapid impacts due to long average transit times, ranging from 5 to 21 years. Our study revealed the importance of combining environmental tracer approaches and a comprehensive sampling campaign (local sources of nitrate, soil water, river water, and groundwater) to identify the nitrate sources in groundwater and its vulnerability. In future, the achieved results will help develop targeted

A Spatial and Temporal Assessment of Non-Point Groundwater Pollution Sources, Tutuila Island, American Samoa

Science.gov (United States)

Shuler, C. K.; El-Kadi, A. I.; Dulaiova, H.; Glenn, C. R.; Fackrell, J.

2015-12-01

The quality of municipal groundwater supplies on Tutuila, the main island in American Samoa, is currently in question. A high vulnerability for contamination from surface activities has been recognized, and there exists a strong need to clearly identify anthropogenic sources of pollution and quantify their influence on the aquifer. This study examines spatial relationships and time series measurements of nutrients and other tracers to identify predominant pollution sources and determine the water quality impacts of the island's diverse land uses. Elevated groundwater nitrate concentrations are correlated with areas of human development, however, the mixture of residential and agricultural land use in this unique village based agrarian setting makes specific source identification difficult using traditional geospatial analysis. Spatial variation in anthropogenic impact was assessed by linking NO3- concentrations and δ15N(NO3) from an extensive groundwater survey to land-use types within well capture zones and groundwater flow-paths developed with MODFLOW, a numerical groundwater model. Land use types were obtained from high-resolution GIS data and compared to water quality results with multiple-regression analysis to quantify the impact that different land uses have on water quality. In addition, historical water quality data and new analyses of δD and δ18O in precipitation, groundwater, and mountain-front recharge waters were used to constrain the sources and mechanisms of contamination. Our analyses indicate that groundwater nutrient levels on Tutuila are controlled primarily by residential, not agricultural activity. Also a lack of temporal variation suggests that episodic pollution events are limited to individual water sources as opposed to the entire aquifer. These results are not only valuable for water quality management on Tutuila, but also provide insight into the sustainability of groundwater supplies on other islands with similar hydrogeology and land

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Theory and user's manual

International Nuclear Information System (INIS)

Rood, A.S.

1992-03-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track 1 and Track 2 assessment of Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1991). The code calculates the limiting soil concentration such that regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: Contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation for transient mass flux input

Atrazine Contamination in Groundwater at Ejura in the Ashanti Region of Ghana

International Nuclear Information System (INIS)

Quaye, F.A.

2012-01-01

The present study the levels Atrazine, deethylatrazine(DEA) and deisopropylatrazine(DIA) in groundwater at Ejura within the Ejura-Sekyedumase District in the Ashanti region of Ghana which is a major maize growing area in the country. A total of twenty five (25) groundwater samples were collected from six(6) sampling sites within the sampling area and were analyzed using a Varian ProstaHPLC system (410) + autosampler, photodiote array (PDA) detector, UV and fluorescence detectors. The mean concentration of atrazine in the groundwater at Ejura is 0.255 μ/L. The maximum concentration of atrazine was 1.530μ/L and a minimum concentration of 0.20μ/L. The maximum and minimum concentrations for deethylatrazine (DEA) and deisopropylatrazine (DIA) are 0.423μ/L and 0.101μ/L and 0.204μ/L and 0.102μL respectively. The Deethylatrazine to Atrazine Ratio (DAR) was calculated; the values were much less than one suggesting a discrete source of contamination. This gives an indication of the pathway of atrazine contamination as being preferential flow. The levels of Atrazine deethylatrazine (DEA) and deisopropylatrazine (DIA) from the samples analyzed were all below WHO's maximum contamination levels (MCL), 2μ/L. (author)

Monitoring of Water and Contaminant Migration at the Groundwater-Surface Water Interface

Science.gov (United States)

2008-08-01

seepage is occurring in a freshwater lake environment and to map the lateral extent of any subsurface contamination at the groundwater –surface water ...and Contaminant Migration at the Groundwater -Surface Water Interface August 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Monitoring of Water and Contaminant Migration at the Groundwater -Surface Water Interface 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Contamination of groundwater by the fumigants ethylene dibromide (EDB) and dibromochloropropane (DBCP) near McBee, South Carolina

Science.gov (United States)

Landmeyer, James E.; Campbell, Bruce G.

2010-01-01

McBee is a small town of about 700 people located in Chesterfield County, South Carolina, in the Sandhills region of the upper Coastal Plain. The halogenated organic compounds ethylene dibromide (EDB) and dibromochloropropane (DBCP) have been detected in several public and domestic supply and irrigation wells since 2002 at concentrations above their U.S. Environmental Protection Agency Maximum Contaminant Limits of 0.05 and 0.2 microgram per liter (µg/L), respectively. The source(s) and release histories of EDB and DBCP to local groundwater are unknown, but believed to be related to their historical use between the 1940s and their ban in the late 1970s as fumigants to control nematode damage in peach orchards. However, gasoline and jet-fuel supplies also contained EDB and are an alternative source of contamination to groundwater. The detection of EDB and DBCP in water wells has raised health concerns because groundwater is the sole source of water supply in the McBee area. In April 2010, forensic, geochemical-based investigation was initiated by the U.S. Geological Survey in cooperation with the Alligator Rural Water & Sewer Company to provide additional data regarding EDB and DBCP in local groundwater. The investigation includes an assessment of the use, release, and disposal history of EDB and DBCP in the area, the distribution of EDB and DBCP concentrations in the unsaturated zone, and transport and fate in groundwater.

Software for modelling groundwater transport and contaminant migration

International Nuclear Information System (INIS)

Gishkelyuk, I.A.

2008-01-01

Facilities of modern software for modeling of groundwater transport and process of contaminant distribution are considered. Advantages of their application are discussed. The comparative analysis of mathematical modeling software of 'Groundwater modeling system' and 'Earth Science Module' from 'COMSOL Multiphysics' is carried out. (authors)

Innovative reactive barrier technologies for regional contaminated groundwater

NARCIS (Netherlands)

Merkel, P.; Weiβ, H.; Teutsch, G.; Rijnaarts, H.H.M.

2000-01-01

At many industrial sites inadequate waste disposal, leakages and war damages have led to severe groundwater contamination on a regional scale. Standard hydraulic groundwater remediation methods, such as pump-and-treat, in most cases do not lead to satisfactory results, due to the persistence of

Prioritization and accelerated remediation of groundwater contamination in the 200 Areas of the Hanford Site, Washington

International Nuclear Information System (INIS)

Wittreich, C.D.; Ford, B.H.

1993-04-01

The Hanford Site, operated by the US Department of Energy (DOE), occupies about 1,450 km 2 (560 mi 2 ) of the southeastern part of Washington State north of the confluence of the Yakima and Columbia Rivers. The Hanford Site is organized into numerically designated operational areas. The 200 Areas, located near the center of the Hanford Site, encompasses the 200 West, East and North Areas and cover an area of over 40 km 2 . The Hanford Site was originally designed, built, and operated to produce plutonium for nuclear weapons using production reactors and chemical reprocessing plants. Operations in the 200 Areas were mainly related to separation of special nuclear materials from spent nuclear fuel and contain related chemical and fuel processing and waste management facilities. Large quantities of chemical and radioactive waste associated with these processes were often disposed to the environment via infiltration structures such as cribs, ponds, ditches. This has resulted in over 25 chemical and radionuclide groundwater plumes, some of which have reached the Columbia River. An Aggregate Area Management Study program was implemented under the Hanford Federal Facility Agreement and Consent Order to assess source and groundwater contamination and develop a prioritized approach for managing groundwater remediation in the 200 Areas. This included a comprehensive evaluation of existing waste disposal and environmental monitoring data and the conduct of limited field investigations (DOE-RL 1992, 1993). This paper summarizes the results of groundwater portion of AAMS program focusing on high priority contaminant plume distributions and the groundwater plume prioritization process. The objectives of the study were to identify groundwater contaminants of concern, develop a conceptual model, refine groundwater contaminant plume maps, and develop a strategy to expedite the remediation of high priority contaminants through the implementation of interim actions

Modeling the migration of radioactive contaminants in groundwater of in situ leaching uranium mine

International Nuclear Information System (INIS)

Li Chunguang; Tai Kaixuan

2011-01-01

The radioactive contamination of groundwater from in situ leaching (ISL) of uranium mining is a widespread environmental problem. This paper analyzed the monitor results of groundwater contaminations for a in situ leaching uranium mine. A dynamic model of contaminants transport in groundwater in ISL well field was established. The processes and mechanisms of contaminant transport in groundwater were simulated numerically for a ISL well field. A small quantity of U and SO 4 2- migrate to outside of well field during ISL production stage. But the migration velocity and distance of contaminations is small, and the concentration is low. Contaminants migrate as anomalistic tooth-shape. The migration trend of U and SO 4 2- is consistent. Numerical modeling can provide an effective approach to analyse the transport mechanism, and forecast and control the migration of contaminants in groundwater in ISL well field. (authors)

California GAMA Program: Sources and Transport of Nitrate in Groundwater in the Livermore Valley Basin, California

International Nuclear Information System (INIS)

Beller, H; Eaton, G F; Ekwurzel, B E; Esser, B K; Hu, Q; Hudson, G B; Leif, R; McNab, W; Moody-Bartel, C; Moore, K; Moran, J E

2005-01-01

A critical component of the State Water Resource Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) Program is to assess the major threats to groundwater resources that supply drinking water to Californians (Belitz et al., 2004). Nitrate concentrations approaching and greater than the maximum contaminant level (MCL) are impairing the viability of many groundwater basins as drinking water sources Source attribution and nitrate fate and transport are therefore the focus of special studies under the GAMA program. This report presents results of a study of nitrate contamination in the aquifer beneath the City of Livermore, where high nitrate levels affect both public supply and private domestic wells. Nitrate isotope data are effective in determining contaminant sources, especially when combined with other isotopic tracers such as stable isotopes of water and tritium-helium ages to give insight into the routes and timing of nitrate inputs to the flow system. This combination of techniques is demonstrated in Livermore, where it is determined that low nitrate reclaimed wastewater predominates in the northwest, while two flowpaths with distinct nitrate sources originate in the southeast. Along the eastern flowpath, (delta) 15 N values greater than 10(per t housand) indicate that animal waste is the primary source. Diminishing concentrations over time suggest that contamination results from historical land use practices. The other flowpath begins in an area where rapid recharge, primarily of low nitrate imported water (identified by stable isotopes of water and a tritium-helium residence time of less than 1 year), mobilizes a significant local nitrate source, bringing groundwater concentrations above the MCL of 45 mg NO 3 L -1 . In this area, artificial recharge of imported water via local arroyos induces flux of the contaminant to the regional aquifer. The low (delta) 15 N value (3.1(per t housand)) in this location implicates synthetic fertilizer

Public health risk assessment of groundwater contamination in Batman, Turkey.

Science.gov (United States)

Nalbantcilar, M Tahir; Pinarkara, Sukru Yavuz

2016-08-01

In this study, a comprehensive analysis of groundwater was performed to assess contamination and phenol content in Batman, Turkey, particularly in residential areas near agriculture, livestock and oil industry facilities. From these areas, where potentially contaminated groundwater used for drinking and irrigation threatens public health, 30 groundwater samples were collected and analyzed for heavy metal concentrations (Al, As, B, Ba, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, NO3, P, Pb, phenol, S, Sb, Se, SO4, Sr, U, and Zn). Compared with the standards of the Environmental Protection Agency, Al, Fe, and Mn concentrations in groundwater exceeded secondary drinking water regulations, NO3 concentrations were high for maximum contaminant levels, and As, Pb, and U concentrations exceeded maximum contaminant level goals in all samples. Ni, Sb, and Se concentrations also exceeded limits set by the Turkish Standards Institution. Nearly all samples revealed concentrations of Se, Sb, Hg, and phenol due to nearby petroleum refineries, oil storage plants, and agricultural and livestock areas. The results obtained from this study indicate that the groundwater in Batman contains elements in concentrations that approach or exceed limits and thus threatens public health with increased blood cholesterol, decreased blood sugar, and circulatory problems.

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Theory and user`s manual

Energy Technology Data Exchange (ETDEWEB)

Rood, A.S.

1992-03-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track 1 and Track 2 assessment of Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1991). The code calculates the limiting soil concentration such that regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: Contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation for transient mass flux input.

Point bars as stratigraphic traps for arsenic contamination in groundwater : Case study of the Ganges River, Bihar, India (abstract)

NARCIS (Netherlands)

Donselaar, M.E.; Bhatt, A.G.; Bruining, J.; Bose, N.; Ghosh, A.K.

2013-01-01

Arsenic-contaminated groundwater causes a wide-spread, serious health risk affecting millions of people worldwide. Focus of the research is the floodplain of the Ganges River in the State of Bihar (India) where groundwater is the principal source of drinking water and irrigation, and where the

Groundwater contamination and risk assessment of industrial complex in Busan Metropolitan City, Korea

Science.gov (United States)

Hamm, S.-Y.; Ryu, S. M.; Cheong, J.-Y.; Woo, Y.-J.

2003-04-01

-HCO3 or Na-HCO3 types. TDS (107-14,500 /L), EC (225-25,500 μS/cm), salinity (100-15,500 /kg), Na+ (13.39-2,866 /L) and Cl- (15.3-7,066 /L) concentrations are also higher than those of general groundwater. This fact indicates that groundwater in study area was polluted by saline water and/or anthropogenic sources. TCE, PCE, 1.1.1-trichloroethane (TCA) were analyzed by Busan Metropolitan City Institute of Health &Environment. PCE and TCA are not detected most of sites, while TCE is detected most of the sites and exceeds drinking water standard of Korea 0.03 /L. It is considered that TCE was derived from variety contamination sources such as car-washing centers, transportation companies, iron molding factories and waste treating companies. Risk assessment to human health and environmental resources by groundwater contamination was conducted. The RBCA Tool Kit for Chemical Releases can be used for the risk assessment at Tier 1 and Tier 2. The risk assessment determines risk-based concentration of constituents of concerns (COCs) that moves through groundwater, soil and air. It also evaluates carcinogenic risk and toxic effect when receptor exposures to the COCs. Tier 1 analysis determines risk-based screening levels (RBSLs) for one-site exposure. Tier 2 analysis evaluates RBSL and/or site-specific target levels (SSTLs) for both on-site and off-site receptor. RBSLs were calculated as 2.2E-2 /L for TCE and as 4.7E-3 /L for PCE at Tier 1 risk assessment. Average concentrations of TCE and PCE from measuring the groundwater samples were 0.15 mg/L and 0.016 mg/L, respectively. The actual measured values are higher than the RBSLs. Carcinogenic risk of TCE to animals was identified as B2 (inadequate or no human evidence but sufficient animal evidence). From this result, we will conduct the further detail risk assessment at Tier 2 level before conducting groundwater remediation. ACKNOWLEDGEMENT The authors wish to acknowledge the financial support of the Korea Science &Engineering

Cone penetrometer testing (CPT) for groundwater contamination

International Nuclear Information System (INIS)

Jordan, J.E.; Van Pelt, R.S.

1993-01-01

Over the past decade, researchers at the Savannah River Site (SRS) and elsewhere have greatly advanced the knowledge of waste site characterization technologies. As a result, many of the techniques used in the past to investigate waste sites have been replaced by newer technologies, designed to provide greater protection for human health and the environment, greater access to suspected zones of contamination, and more accurate information of subsurface conditions. Determining the most environmentally sound method of assessing a waste unit is a major component of the SRS environmental restoration program. In an effort to understand the distribution and migration of contaminants in the groundwater system, the cone penetrometer investigation of the A/M-Area Southern Sector was implemented. The program incorporated a phased approach toward characterization by first using the CPT to delineate the plume boundary, followed by installing groundwater monitoring wells. The study provided the additional hydrogeologic information necessary to better understand the nature and extent of the contaminant plume (Fig. 1) and the hydrogeologic system in the Southem Sector. This data is essential for the optimal layout of the planned groundwater monitoring well network and recovery system to remediate the aquifers in the area. A number of other test locations were selected in the area during this study for lithologic calibration of the tool and to collect confirmation water samples from the aquifer. Cone penetrometer testing and hydrocone sampling, were performed at 17 sites (Fig. 2). The hydrocone, a tool modification to the CPT, was used to collect four groundwater samples from confined aquifers. These samples were analyzed by SRS laboratories. Elevated levels of chlorinated compounds were detected from these samples and have aided in further delineating the southern sector contaminant plume

Hydrodynamic analysis application of contaminated groundwater remediation to oil hydrocarbons

Directory of Open Access Journals (Sweden)

Pajić Predrag R.

2017-01-01

Full Text Available In this paper, the application of the hydrodynamic analysis in the selected ‘pumping and treatment’ remediation method of groundwater hydrocarbon pollution in the case of the Pancevo oil refinery is examined. The applied hydrodynamic analysis represents a regular and necessary approach in modern hydrogeology. Previous chemical analysis of soil and groundwater samples at observation objects revealed their pollution by oil products. New researches included the constraction of 12 piezometric boreholes of varying depths, geoelectric soil sounding, ‘in situ’ measurement of the present contaminant, detected as a hydrophobic phase of LNAPL, chemical analysis of soil and groundwater samples with emphasis on total petroleum hydrocarbons (TPH content, total fats and mineral oils, mercury cations and other characteristic compounds, etc. These researches define the volume of contamination issued by the ‘light’ (LNAPL contamination phase. The selected remediation method for this type of pollution is the ‘Pump and Treat’ method, which implies the pumping of contaminated groundwater from aquifer and their subsequent treatment. A hydrodynamic method was used to select the optimal hydrotechnical solution for LNAPL extraction. On the mathematical model, the prediction calculations for two variant solutions were carried out (‘hydraulic isolation’ and complex for the application of groundwater contamination remediation characterized as front pollution substance (by extraction and injection wells or infiltration pool. By extraction wells performing, it would be possible to remove the LNAPL from the surface of the water with special pumps-skimmers. The importance of the hydrodynamic method application is, in addition to the hydrotechnical solution selection for the LNAPL drainage, the provision of quality basis for the dimensioning of these objects based on the results of the groundwater balance.

Hydrochemistry and Characteristics of Groundwater: Case Study Water Contamination at Citarum River Upstream

Directory of Open Access Journals (Sweden)

Mohamad Sapari Dwi Hadian

2017-12-01

Full Text Available Rancaekek and Sayang area, West Java, are the area where many industrial factories are located.Thus, the region becomes the targeted destination for industrial development.The  population in the area is rising due to the growth of industries causing the regional development becomes uncontrollable. In addition, the constant increment of waste and also poor-coordinated disposal systems may result in groundwater contamination in the areas. The rapid growth of the area increase the need for groundwater as well as the need for more research about contamination at Rancaekek and Sayang. The research aims to explore the spread of groundwater contamination in the area. The research method is carried out based on the analysis of Geological Mapping, Hydrogeological Mapping and chemical characteristics of the groundwater in the area. Chemical analyses of the groundwater were conducted through laboratory test of groundwater samples at specific spots of dug wells. The lab test results were further analyzed to determine the contamination zone. The findings reveal that the distribution of contamination in the area follow the shallow ground water flow patterns, the water contamination contains heavy metal and there is degradation of soil fertility. The findings suggest the stakeholders to delineate the contaminated area, and increase the dissemination of environmental awareness.

Evidence for Legacy Contamination of Nitrate in Groundwater of North Carolina Using Monitoring and Private Well Data Models

Science.gov (United States)

Messier, K. P.; Kane, E.; Bolich, R.; Serre, M. L.

2014-12-01

Nitrate (NO3-) is a widespread contaminant of groundwater and surface water across the United States that has deleterious effects to human and ecological health. Legacy contamination, or past releases of NO3-, is thought to be impacting current groundwater and surface water of North Carolina. This study develops a model for predicting point-level groundwater NO3- at a state scale for monitoring wells and private wells of North Carolina. A land use regression (LUR) model selection procedure known as constrained forward nonlinear regression and hyperparameter optimization (CFN-RHO) is developed for determining nonlinear model explanatory variables when they are known to be correlated. Bayesian Maximum Entropy (BME) is then used to integrate the LUR model to create a LUR-BME model of spatial/temporal varying groundwater NO3- concentrations. LUR-BME results in a leave-one-out cross-validation r2 of 0.74 and 0.33 for monitoring and private wells, effectively predicting within spatial covariance ranges. The major finding regarding legacy sources NO3- in this study is that the LUR-BME models show the geographical extent of low-level contamination of deeper drinking-water aquifers is beyond that of the shallower monitoring well. Groundwater NO3- in monitoring wells is highly variable with many areas predicted above the current Environmental Protection Agency standard of 10 mg/L. Contrarily, the private well results depict widespread, low-level NO3-concentrations. This evidence supports that in addition to downward transport, there is also a significant outward transport of groundwater NO3- in the drinking water aquifer to areas outside the range of sources. Results indicate that the deeper aquifers are potentially acting as a reservoir that is not only deeper, but also covers a larger geographical area, than the reservoir formed by the shallow aquifers. Results are of interest to agencies that regulate surface water and drinking water sources impacted by the effects of

Increased concentrations of potassium in heartwood of trees in response to groundwater contamination

Science.gov (United States)

Vroblesky, Don A.; Yanosky, Thomas M.; Siegel, Frederic R.

1992-03-01

The wood of tuliptrees ( Liriodendron tulipifera L.) growing above groundwater contamination from a hazardous-waste landfill in Maryland contained elevated concentrations of potassium (K). The groundwater contamination also contained elevated concentrations of dissolved K, as well as arsenic (As), cadmium (Cd), chloride (Cl), iron (Fe), manganese (Mn), zinc (Zn), and organic solvents. The dissolved K is derived from disposed smoke munitions. The excess K in the tuliptrees is concentrated in the heartwood, the part of the xylem most depleted in K in trees growing outside of the contamination. These data show that the uptake and translocation of K by tuliptrees can be strongly influenced by the availability of K in groundwater contamination and suggest the utility of this species as an areal indicator of groundwater contamination.

Geogenic Groundwater Contamination: A Case Study Of Canakkale - Western Turkey

Science.gov (United States)

Deniz, Ozan; Çalık, Ayten

2016-04-01

Study area is located NW of Turkey. Total area of the drainage basin is 465 square kilometers and mostly covered by volcanic rocks. Majority of these rocks have highly altered and lost their primary properties because of alteration processes. Especially argillic alteration is common. Tectonic movements and cooling fractures were created suitable circulation environment of groundwater in the rocks (secondary porosity). Alteration affects the composition of groundwater and some rock elements pass into groundwater during the movement of water in the cavities of rocks. High concentration of natural contaminants related to water-rock interaction in spring water has been studied in this research. Field measurements such as pH, electrical conductivity, temperature, oxidation-reduction potential and salinity carried out in 500 water points (spring, drilling, well and stream). 150 water samples taken from the water points and 50 rock samples taken from the source of springs has been investigated in point of major anion-cations, heavy metals and trace elements. Some components in the water such as pH (3.5-9.1), specific electrical conductivity (84-6400 microS/cm), aluminum (27-44902 ppb), iron (10-8048 ppb), manganese (0.13-8740 ppb), nickel (0.2-627 ppb), lead (0.1-42.5 ppb) and sulphate (10 to 1940 ppm) extremely high or low in the springs sourced from especially highly altered Miocene aged volcanic rocks. Some measured parameters highly above according to European Communities Drinking Water Regulations (2007) and TS266 (2015-Intended for Human Consumption Water Regulations of Turkey) drinking water standards. The most common element which is found in the groundwater is aluminum that is higher than to the drinking water standards (200 microg/L). The highest levels of the Al values measured in acidic waters with very low pH (3.4) emerging from altered volcanic rocks because of acid mine drainage in Obakoy district, north of the study area. The abundance of this element in

The groundwater contribution to surface water contamination in a region with intensive agricultural land use (Noord-Brabant, The Netherlands)

International Nuclear Information System (INIS)

Rozemeijer, J.C.; Broers, H.P.

2007-01-01

Traditionally, monitoring of soil, groundwater and surface water quality is coordinated by different authorities in the Netherlands. Nowadays, the European Water Framework Directive (EU, 2000) stimulates an integrated approach of the complete soil-groundwater-surface water system. Based on water quality data from several test catchments, we propose a conceptual model stating that stream water quality at different discharges is the result of different mixing ratios of groundwater from different depths. This concept is used for a regional study of the groundwater contribution to surface water contamination in the Dutch province of Noord-Brabant, using the large amount of available data from the regional monitoring networks. The results show that groundwater is a dominant source of surface water contamination. The poor chemical condition of upper and shallow groundwater leads to exceedance of the quality standards in receiving surface waters, especially during quick flow periods. - Water quality monitoring data show the importance of the groundwater contribution to surface water pollution

Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado

Energy Technology Data Exchange (ETDEWEB)

1993-12-01

This Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells. This risk assessment evaluates the most contaminated monitor wells at the processing site. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado

International Nuclear Information System (INIS)

1993-12-01

This Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy's (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells. This risk assessment evaluates the most contaminated monitor wells at the processing site. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium

Emerging contaminants: strategies for the assessment of emerging groundwater contaminants 

OpenAIRE

Stuart, Marianne; Lapworth, Dan; Manamsa, Katya; Crane, Emily; White, Debbie

2016-01-01

Emerging contaminants in groundwater are important. An increasing range of compounds is being detected Urban areas show impact of sewage and industrial wastewater. Some ECs are probably no threat to drinking water at such µg/L concentrations, e.g. caffeine. Others may prove to be in the future. There is little information on their impact on other groundwater receptors in the environment. We are still far from understanding which of these compounds could be important

Changes of Groundwater Quality in the Sorrounding Pollution Sources Due to Earthquake Dissaster

Directory of Open Access Journals (Sweden)

Sudarmadji Sudarmadji

2016-05-01

Full Text Available Groundwater is the main domestic water supply of the population of the Yogyakarta Special Region, both in the urban and as well as in the rural area due to its quantity and quality advantages. The rapid population growth has caused an increase of groundwater demand, consequently it is facing some problems to the sustainability of groundwater supply. Lowering of groundwater level has been observed in some places, as well as the degradation of groundwater quality. Earthquake which stroke Yogyakarta on 27 May 2006, damaged buildings and other infrastructures in the area, including roads and bridges. It might also damage the underground structures such as septic tanks, and pipes underneath the earth surface. It might cause cracking of the geologic structures. Furthermore, the damage of underneath infrastructures might create groundwater quality changes in the area. Some complains of local community on lowering and increasing groundwater level and groundwater quality changes were noted. Field observation and investigation were conducted, including collection of groundwater samples close to (the pollution sources. Laboratory analyses indicated that some parameters increased to exceed the drinking water quality standards. The high content of Coli form bacteria possibly was caused by contamination of nearby septic tanks or other pollution sources to the observed groundwater in the dug well.

Field demonstration of rapid turnaround, multilevel groundwater screening

International Nuclear Information System (INIS)

Tingle, A.R.; Baker, L.; Long, D.D.

1994-01-01

A combined technology approach to rapidly characterizing source area and downgradient groundwater associated with a past fuel spill has been field tested. The purpose of this investigation was to determine the presence and extent of fuel-related compounds or indications of their biodegradation in groundwater. The distance from the source area to be investigated was established by calculating the potential extent of a plume based only on groundwater flow velocities. To accomplish this objective, commercially available technologies were combined and used to rapidly assess the source area and downgradient groundwater associated with the fuel discharge. The source of contamination that was investigated overlies glacial sand and gravel outwash deposits. Historical data suggest that from 1955 to 1970 as many as 1 to 6 million pi of aviation gasoline (AVGAS) were god at the study area. Although the remedial investigation (RI) for this study area indicated fuel-related groundwater contamination at the source area, fuel-related contamination was not detected in downgradient monitoring wells. Rapid horizontal groundwater velocities and the 24-year time span from the last reported spill farther suggest that a plume of contaminated groundwater could extend several thousand feet downgradient. The lack of contamination downgradient from the source suggests two possibilities: (1) monitoring wells installed during the RI did not intersect the plume or (2) fuel-related compounds had naturally degraded

Increased concentrations of potassium in heartwood of trees in response to groundwater contamination

Science.gov (United States)

Vroblesky, D.A.; Yanosky, T.M.; Siegel, F.R.

1992-01-01

The wood of tuliptrees (Liriodendron tulipifera L.) growing above groundwater contamination from a hazardous-waste landfill in Maryland contained elevated concentrations of potassium (K). The groundwater contamination also contained elevated concentrations of dissolved K, as well as arsenic (As), cadmium (Cd), chloride (Cl), iron (Fe), manganese (Mn), zinc (Zn), and organic solvents. The dissolved K is derived from disposed smoke munitions. The excess K in the tuliptrees is concentrated in the heartwood, the part of the xylem most depleted in K in trees growing outside of the contamination. These data show that the uptake and translocation of K by tuliptrees can be strongly influenced by the availability of K in groundwater contamination and suggest the utility of this species as an areal indicator of groundwater contamination. ?? 1992 Springer-Verlag New York Inc.

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Theory and user's manual

Energy Technology Data Exchange (ETDEWEB)

Rood, A.S.

1992-03-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track 1 and Track 2 assessment of Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1991). The code calculates the limiting soil concentration such that regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: Contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation for transient mass flux input.

High 36Cl/Cl ratios in Chernobyl groundwater

International Nuclear Information System (INIS)

Roux, Céline; Le Gal La Salle, Corinne; Simonucci, Caroline; Van Meir, Nathalie; Fifield, L. Keith; Diez, Olivier; Bassot, Sylvain

2014-01-01

After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A 90 Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, 36 Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater. 36 Cl/Cl ratios measured in groundwater, trench soil water and leaf leachates are 1–5 orders of magnitude higher than the theoretical natural 36 Cl/Cl ratio. This contamination occurred after the Chernobyl explosion and currently persists. Trench T22 acts as an obvious modern point source of 36 Cl, however other sources have to be involved to explain such contamination. 36 Cl contamination of groundwater can be explained by dilution of trench soil water by uncontaminated water (rainwater or deep groundwater). With a plume extending further than that of 90 Sr, radionuclide which is impacted by retention and decay processes, 36 Cl can be considered as a suitable tracer of contamination from the trench in groundwater provided that modern release processes of 36 Cl from trench soil are better characterized. - Highlights: • High 36 Cl/Cl ratios measured in the Chernobyl Pilot Site groundwater. • Trench T22 acts as a modern source of groundwater contamination by 36 Cl but other sources are involved. • Contamination results from dilution of a contaminated “T22” soil water with rainwater. • Processes involved in the modern release need to be investigated

An early warning system for groundwater pollution based on the assessment of groundwater pollution risks.

Science.gov (United States)

Zhang, Weihong.; Zhao, Yongsheng; Hong, Mei; Guo, Xiaodong

2009-04-01

Groundwater pollution usually is complex and concealed, remediation of which is difficult, high cost, time-consuming, and ineffective. An early warning system for groundwater pollution is needed that detects groundwater quality problems and gets the information necessary to make sound decisions before massive groundwater quality degradation occurs. Groundwater pollution early warning were performed by considering comprehensively the current groundwater quality, groundwater quality varying trend and groundwater pollution risk . The map of the basic quality of the groundwater was obtained by fuzzy comprehensive evaluation or BP neural network evaluation. Based on multi-annual groundwater monitoring datasets, Water quality state in sometime of the future was forecasted using time-sequenced analyzing methods. Water quality varying trend was analyzed by Spearman's rank correlative coefficient.The relative risk map of groundwater pollution was estimated through a procedure that identifies, cell by cell,the values of three factors, that is inherent vulnerability, load risk of pollution source and contamination hazard. DRASTIC method was used to assess inherent vulnerability of aquifer. Load risk of pollution source was analyzed based on the potential of contamination and pollution degree. Assessment index of load risk of pollution source which involves the variety of pollution source, quantity of contaminants, releasing potential of pollutants, and distance were determined. The load risks of all sources considered by GIS overlay technology. Early warning model of groundwater pollution combined with ComGIS technology organically, the regional groundwater pollution early-warning information system was developed, and applied it into Qiqiha'er groundwater early warning. It can be used to evaluate current water quality, to forecast water quality changing trend, and to analyze space-time influencing range of groundwater quality by natural process and human activities. Keywords

Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

Science.gov (United States)

Abdalla, Fathy; Khalil, Ramadan

2018-05-01

The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physicochemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3-, Cl- and SO42-, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3- concentrations and high bacteria counts. A scatter plot of HCO3- versus Ca indicates that 58% of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94% of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3%), moderate (36.3%), low (13.3%), and very low (11.1%) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

Review of risk from potential emerging contaminants in UK groundwater.

Science.gov (United States)

Stuart, Marianne; Lapworth, Dan; Crane, Emily; Hart, Alwyn

2012-02-01

This paper provides a review of the types of emerging organic groundwater contaminants (EGCs) which are beginning to be found in the UK. EGCs are compounds being found in groundwater that were previously not detectable or known to be significant and can come from agricultural, urban and rural point sources. EGCs include nanomaterials, pesticides, pharmaceuticals, industrial compounds, personal care products, fragrances, water treatment by-products, flame retardants and surfactants, as well as caffeine and nicotine. Many are relatively small polar molecules which may not be effectively removed by drinking water treatment. Data from the UK Environment Agency's groundwater screening programme for organic pollutants found within the 30 most frequently detected compounds a number of EGCs such as pesticide metabolites, caffeine and DEET. Specific determinands frequently detected include pesticides metabolites, pharmaceuticals including carbamazepine and triclosan, nicotine, food additives and alkyl phosphates. This paper discusses the routes by which these compounds enter groundwater, their toxicity and potential risks to drinking water and the environment. It identifies challenges that need to be met to minimise risk to drinking water and ecosystems. Copyright © 2012. Published by Elsevier B.V.

Is nutrient contamination of groundwater causing eutrophication of groundwater-fed meadows?

NARCIS (Netherlands)

Pieterse, N.M.; Olde Venterink, H.; Schot, P.P.; Verkroost, A.W.M.

2005-01-01

There is an ongoing debate as to whether nutrient contamination of groundwater under agricultural fields may cause nutrient-enrichment and subsequent eutrophication in discharge areas. Often, there is only circumstantial evidence to support this supposition (proximity of agricultural fields,

Establishing indices for groundwater contamination risk assessment in the vicinity of hazardous waste landfills in China

International Nuclear Information System (INIS)

Li Ying; Li Jinhui; Chen Shusheng; Diao Weihua

2012-01-01

Groundwater contamination by leachate is the most damaging environmental impact over the entire life of a hazardous waste landfill (HWL). With the number of HWL facilities in China rapidly increasing, and considering the poor status of environmental risk management, it is imperative that effective environmental risk management methods be implemented. A risk assessment indices system for HWL groundwater contamination is here proposed, which can simplify the risk assessment procedure and make it more user-friendly. The assessment framework and indices were drawn from five aspects: source term, underground media, leachate properties, risk receptors and landfill management quality, and a risk assessment indices system consisting of 38 cardinal indicators was established. Comparison with multimedia models revealed that the proposed indices system was integrated and quantitative, that input data for it could be easily collected, and that it could be widely used for environmental risk assessment (ERA) in China. - Highlights: ► No comprehensive environmental risk assessment method for hazardous waste management is proposed in China. ► An assessment indices system is established for groundwater contamination in the vicinity of hazardous waste landfill. ► All indicators are quantitative and applicable in China. - Capsule: This research identified critical indices and established a system for environmental risk assessment for groundwater contamination in the vicinity of HWLs in China.

Integrated socio-hydrogeological approach to tackle nitrate contamination in groundwater resources. The case of Grombalia Basin (Tunisia).

Science.gov (United States)

Re, V; Sacchi, E; Kammoun, S; Tringali, C; Trabelsi, R; Zouari, K; Daniele, S

2017-09-01

Nitrate contamination still remains one of the main groundwater quality issues in several aquifers worldwide, despite the perduring efforts of the international scientific community to effectively tackle this problem. The classical hydrogeological and isotopic investigations are obviously of paramount importance for the characterization of contaminant sources, but are clearly not sufficient for the correct and long-term protection of groundwater resources. This paper aims at demonstrating the effectiveness of the socio-hydrogeological approach as the best tool to tackle groundwater quality issues, while contributing bridging the gap between science and society. An integrated survey, including land use, hydrochemical (physicochemical parameters and major ions) and isotopic (δ 15 N NO3 and δ 18 O NO3 ) analyses, coupled to capacity building and participatory activities was carried out to correctly attribute the nitrate origin in groundwater from the Grombalia Basin (North Tunisia), a region where only synthetic fertilizers have been generally identified as the main source of such pollution. Results demonstrates that the basin is characterized by high nitrate concentrations, often exceeding the statutory limits for drinking water, in both the shallow and deep aquifers, whereas sources are associated to both agricultural and urban activities. The public participation of local actors proved to be a fundamental element for the development of the hydrogeological investigation, as it permitted to obtain relevant information to support data interpretation, and eventually guaranteed the correct assessment of contaminant sources in the studied area. In addition, such activity, if adequately transferred to regulators, will ensure the effective adoption of management practices based on the research outcomes and tailored on the real needs of the local population, proving the added value to include it in any integrated investigation. Copyright © 2017 Elsevier B.V. All rights

Investigation of Ground-Water Contamination at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina

Science.gov (United States)

Vroblesky, Don A.; Casey, Clifton C.; Petkewich, Matthew D.; Lowery, Mark A.; Conlon, Kevin J.; Harrelson, Larry G.

2007-01-01

The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated volatile organic compound ground-water contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina. The primary contaminants of interest are tetrachloroethene, 1,1,1-trichloroethane, trichloroethene, cis-1,2-dichloroethene, vinyl chloride, 1,1-dichloroethane, and 1,1-dichloroethene. In general, the hydrogeology of Solid Waste Management Unit 12 consists of a surficial aquifer, composed of sand to clayey sand, overlain by dense clay that extends from about land surface to a depth of about 8 to 10 feet and substantially limits local recharge. During some months in the summer, evapotranspiration and limited local recharge result in ground-water level depressions in the forested area near wells 12MW-12S and 12MW-17S, seasonally reflecting the effects of evapotranspiration. Changes in surface-water levels following Hurricane Gaston in 2004 resulted in a substantial change in the ground-water levels at the site that, in turn, may have caused lateral shifting of the contaminant plume. Hydraulic conductivity, determined by slug tests, is higher along the axis of the plume in the downgradient part of the forests than adjacent to the plume, implying that there is some degree of lithologic control on the plume location. Hydraulic conductivity, hydraulic gradient, sulfur-hexafluoride measurements, and historical data indicate that ground-water flow rates are substantially slower in the forested area relative to upgradient areas. The ground-water contamination, consisting of chlorinated volatile organic compounds, extends eastward in the surficial aquifer from the probable source area near a former underground storage tank. Engineered remediation approaches include a permeable reactive barrier and phytoremediation. The central part of the permeable reactive barrier along the

Hydrogeologic controls on ground-water and contaminant discharge to the Columbia River near the Hanford Townsite

International Nuclear Information System (INIS)

Luttrell, S.P.; Newcomer, D.R.; Teel, S.S.; Vermeul, V.R.

1992-11-01

The purpose of this study is to quantify ground-water and contaminant discharge to the Columbia River in the Hanford Townsite vicinity. The primary objectives of the work are to: describe the hydrogeologic setting and controls on ground-water movement and contaminant discharge to the Columbia River; understand the river/aquifer relationship and its effects on contaminant discharge to the Columbia River; quantify the ground-water and contaminant mass discharge to the Columbia River; and provide data that may be useful for a three-dimensional model of ground-water flow and contaminant transport in the Hanford Townsite study area. The majority of ground-water contamination occurs within the unconfined aquifer; therefore, ground-water and contaminant discharge from the unconfined aquifer is the emphasis of this study. The period of study is primarily from June 1990 through March 1992

Global aquifers dominated by fossil groundwaters but wells vulnerable to modern contamination

Science.gov (United States)

Jasechko, Scott; Perrone, Debra; Befus, Kevin M.; Bayani Cardenas, M.; Ferguson, Grant; Gleeson, Tom; Luijendijk, Elco; McDonnell, Jeffrey J.; Taylor, Richard G.; Wada, Yoshihide; Kirchner, James W.

2017-06-01

The vulnerability of groundwater to contamination is closely related to its age. Groundwaters that infiltrated prior to the Holocene have been documented in many aquifers and are widely assumed to be unaffected by modern contamination. However, the global prevalence of these `fossil' groundwaters and their vulnerability to modern-era pollutants remain unclear. Here we analyse groundwater carbon isotope data (12C, 13C, 14C) from 6,455 wells around the globe. We show that fossil groundwaters comprise a large share (42-85%) of total aquifer storage in the upper 1 km of the crust, and the majority of waters pumped from wells deeper than 250 m. However, half of the wells in our study that are dominated by fossil groundwater also contain detectable levels of tritium, indicating the presence of much younger, decadal-age waters and suggesting that contemporary contaminants may be able to reach deep wells that tap fossil aquifers. We conclude that water quality risk should be considered along with sustainable use when managing fossil groundwater resources.

Identification of Groundwater Nitrate Contamination from Explosives Used in Road Construction: Isotopic, Chemical, and Hydrologic Evidence.

Science.gov (United States)

Degnan, James R; Böhlke, J K; Pelham, Krystle; Langlais, David M; Walsh, Gregory J

2016-01-19

Explosives used in construction have been implicated as sources of NO3(-) contamination in groundwater, but direct forensic evidence is limited. Identification of blasting-related NO3(-) can be complicated by other NO3(-) sources, including agriculture and wastewater disposal, and by hydrogeologic factors affecting NO3(-) transport and stability. Here we describe a study that used hydrogeology, chemistry, stable isotopes, and mass balance calculations to evaluate groundwater NO3(-) sources and transport in areas surrounding a highway construction site with documented blasting in New Hampshire. Results indicate various groundwater responses to contamination: (1) rapid breakthrough and flushing of synthetic NO3(-) (low δ(15)N, high δ(18)O) from dissolution of unexploded NH4NO3 blasting agents in oxic groundwater; (2) delayed and reduced breakthrough of synthetic NO3(-) subjected to partial denitrification (high δ(15)N, high δ(18)O); (3) relatively persistent concentrations of blasting-related biogenic NO3(-) derived from nitrification of NH4(+) (low δ(15)N, low δ(18)O); and (4) stable but spatially variable biogenic NO3(-) concentrations, consistent with recharge from septic systems (high δ(15)N, low δ(18)O), variably affected by denitrification. Source characteristics of denitrified samples were reconstructed from dissolved-gas data (Ar, N2) and isotopic fractionation trends associated with denitrification (Δδ(15)N/Δδ(18)O ≈ 1.31). Methods and data from this study are expected to be applicable in studies of other aquifers affected by explosives used in construction.

Application of groundwater residence time tracers and broad screening for micro-organic contaminants in the Indo-Gangetic aquifer system

Science.gov (United States)

Lapworth, Dan; Das, Prerona; Mukherjee, Abhijit; Petersen, Jade; Gooddy, Daren; Krishan, Gopal

2017-04-01

Groundwater abstracted from aquifers underlying urban centres across India provide a vital source of domestic water. Abstraction from municipal and private supplies is considerable and growing rapidly with ever increasing demand for water from expanding urban populations. This trend is set to continue. The vulnerability of deeper aquifers (typically >100 m below ground) used for domestic water to contamination migration from often heavily contaminated shallow aquifer systems has not been studies in detail in India. This paper focusses on the occurrence of micro-organic contaminants within sedimentary aquifers beneath urban centres which are intensively pumped for drinking water and domestic use. New preliminary results from a detailed case study undertaken across Varanasi, a city with an estimated population of ca. 1.5 million in Uttar Pradesh. Micro -organic groundwater quality status and evolution with depth is investigated through selection of paired shallow and deep sites across the city. These results are considered within the context of paired groundwater residence time tracers within the top 150m within the sedimentary aquifer system. Groundwater emerging contaminant results are compared with surface water quality from the Ganges which is also used for drinking water supply. Broad screening for >800 micro-organic compounds was undertaken. Age dating tools were employed to constrain and inform a conceptual model of groundwater recharge and contaminant evolution within the sedimentary aquifer system.

Assessment of groundwater quality and contamination problems ascribed to an abandoned uranium mine (Cunha Baixa region, Central Portugal)

Science.gov (United States)

Neves, O.; Matias, M. J.

2008-02-01

The assessment of groundwater quality and its environmental implications in the region of the abandoned Cunha Baixa uranium mine (Central Portugal) was carried out from 1995 to 2004. Shallow groundwater is the major water supply source for irrigation in the neighbourhood of Cunha Baixa village. Water samples from the mine site as well as from private wells were collected in order to identify the mining impact on water composition, the extent of contamination and the seasonal and temporal groundwater quality variations. Some of the sampled private wells contain waters having low pH (risks. Nevertheless, this study indicates that groundwater contamination suffered a small decrease from 1999 to 2004. The bioaccumulation of toxic metals such as Al, Mn, and U within the food chain may cause a serious health hazard to the Cunha Baixa village inhabitants.

Comparative metagenomics reveals impact of contaminants on groundwater microbiomes

Directory of Open Access Journals (Sweden)

Christopher L Hemme

2015-10-01

Full Text Available To understand patterns of geochemical cycling in pristine versus contaminated groundwater ecosystems, pristine shallow groundwater (FW301 and contaminated groundwater (FW106 samples from the Oak Ridge Integrated Field Research Center (OR-IFRC were sequenced and compared to each other to determine phylogenetic and metabolic difference between the communities. Proteobacteria (e.g., Burkholderia, Pseudomonas are the most abundant lineages in the pristine community, though a significant proportion (>55% of the community is composed of poorly characterized low abundance (individually <1% lineages. The phylogenetic diversity of the pristine community contributed to a broader diversity of metabolic networks than the contaminated community. In addition, the pristine community encodes redundant and mostly complete geochemical cycles distributed over multiple lineages and appears capable of a wide range of metabolic activities. In contrast, many geochemical cycles in the contaminated community appear truncated or minimized due to decreased biodiversity and dominance by Rhodanobacter populations capable of surviving the combination of stresses at the site. These results indicate that the pristine site contains more robust and encodes more functional redundancy than the stressed community, which contributes to more efficient nutrient cycling and adaptability than the stressed community.

Persistent and emerging micro-organic contaminants in Chalk groundwater of England and France

International Nuclear Information System (INIS)

Lapworth, D.J.; Baran, N.; Stuart, M.E.; Manamsa, K.; Talbot, J.

2015-01-01

The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n = 16), pesticides (n = 14) and pharmaceuticals, personal care and lifestyle products (n = 12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings. - Highlights: • Broad range of microorganics detected in Chalk groundwater in England and France. • Plasticisers, pesticides, BPA and THM detected at the highest concentrations. • Pesticides higher in outcrop Chalk, caffeine and BPA at concealed sites. • Occurrences show some relationship to land use, borehole depth and water level. - Broad screening reveals for the first time the extent of emerging microorganic pollution in Chalk groundwater sources across England and France

A Sustainability Assessment Methodology for Prioritizing the Technologies of Groundwater Contamination Remediation

DEFF Research Database (Denmark)

An, Da; Xi, Beidou; Wang, Yue

2016-01-01

More and more groundwater has 23 been polluted recently, and technologies for groundwater contamination remediation are of vital importance; however, it is usually difficult for the users to select the most suitable technology among multiple alternatives. In order to address this, this study aims...... at developing a sustainability assessment framework for prioritizing the technologies for groundwater contamination remediation by combining the concept of sustainability and multi-criteria decision making (MCDM) method. A criterion system which consists of six criteria in three aspects has been proposed...... for sustainability assessment of technologies for groundwater contamination remediation, and a novel MCDM method by combining the logarithmic fuzzy preference programming based fuzzy analytic hierarchy process and the improved ELECTRE method has been developed for prioritizing the alternatives. In order...

Arsenic, manganese and aluminum contamination in groundwater resources of Western Amazonia (Peru).

Science.gov (United States)

de Meyer, Caroline M C; Rodríguez, Juan M; Carpio, Edward A; García, Pilar A; Stengel, Caroline; Berg, Michael

2017-12-31

This paper presents a first integrated survey on the occurrence and distribution of geogenic contaminants in groundwater resources of Western Amazonia in Peru. An increasing number of groundwater wells have been constructed for drinking water purposes in the last decades; however, the chemical quality of the groundwater resources in the Amazon region is poorly studied. We collected groundwater from the regions of Iquitos and Pucallpa to analyze the hydrochemical characteristics, including trace elements. The source aquifer of each well was determined by interpretation of the available geological information, which identified four different aquifer types with distinct hydrochemical properties. The majority of the wells in two of the aquifer types tap groundwater enriched in aluminum, arsenic, or manganese at levels harmful to human health. Holocene alluvial aquifers along the main Amazon tributaries with anoxic, near pH-neutral groundwater contained high concentrations of arsenic (up to 700μg/L) and manganese (up to 4mg/L). Around Iquitos, the acidic groundwater (4.2≤pH≤5.5) from unconfined aquifers composed of pure sand had dissolved aluminum concentrations of up to 3.3mg/L. Groundwater from older or deeper aquifers generally was of good chemical quality. The high concentrations of toxic elements highlight the urgent need to assess the groundwater quality throughout Western Amazonia. Copyright © 2017 Elsevier B.V. All rights reserved.

Spatial control of groundwater contamination, using principal ...

Indian Academy of Sciences (India)

probe into the spatial controlling processes of groundwater contamination, using principal component analysis (PCA). ... topography, soil type, depth of water levels, and water usage. Thus, the ... of effective sites for infiltration of recharge water.

Hexavalent Chromium: Analysis of the Mechanism of Groundwater Contamination in a Former Industrial Site in the Province of Vicenza (Northern Italy

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Valentina Accoto

2017-01-01

Full Text Available The study consisted in the analysis of the mobilization mechanisms of hexavalent chromium (Cr(VI into groundwater from a decommissioned contaminated factory. The site is located in the Province of Vicenza and formerly was a chrome-plating plant. The subsoil consists predominantly of gravelly deposits with a thickness of at least one hundred meters. An unconfined aquifer is present with water table at about 23 m depth bgl. During the seven years of monitoring (2008-2014, the fluctuation of groundwater level was more than 6 m; hydraulic conductivity is about 1.0E-03 m/s and groundwater seepage velocity about 12 m/day. At the area of the source of contamination, the unsaturated soil is contaminated by hexavalent chromium throughout the thickness: concentrations range from 200 to 500 mg/kg. At the bottom of zone of groundwater level fluctuation, the hexavalent chromium concentration decreases to below the detection limit. The available data (e.g. hexavalent chromium concentrations in groundwater, groundwater level, local rainfall give the opportunity to assess the effects, on the magnitude of groundwater contamination, of the effective infiltration versus the fluctuation of groundwater level. The main analysis was performed on a statistical basis, in order to find out which of the two factors was most likely related to the periodic peaks of hexavalent chromium concentration in groundwater. Statistical analysis results were verified by a mass balance. Data show that at the site both the effective infiltration through the unsaturated zone and the leaching of soil contaminated by groundwater, when it exceeds a certain piezometric level, lead to peak concentrations of hexavalent chromium, even if with characteristics and effects different.

An approach to delineate the contaminated groundwater in landfill based on Electrical Resistivity Imaging Technique

International Nuclear Information System (INIS)

Nor Dalila Desa; Lakam Mejus; Mohd Tadza Abdul Rahman; Kamarudin Samuding; Roslanzairi Mostapa; Mod Omar Hassan

2010-01-01

Full text: The occurrence of contaminated groundwater can often be recognized by a decrease in formation of resistivity values, since the latter is primarily dependent on the resistivity of the pore water. Landfills can be considered as one of major source of contamination that contributes to air, land and water pollution. Landfills are supposed to have a protective bottom layer (barrier layer) to prevent contaminants from getting into the groundwater that exist almost everywhere underground. However, if there is no layer or if it is cracked, water percolating through landfills produces leachate can make their way down into the groundwater system. In geophysical studies, the various properties of materials on earth are known as the anomaly of the Earth's sub surface. It is important to understand which physical properties are associated with, and effective for, a particular target and geophysical method. This paper reviews the needs of geophysical field for mapping subsurface geology and features occurance. Electrical Resistivity Imaging (ERI) technique has been chosen for it has become one of the promising methods in order to obtain preliminary information of subsurface variance materials based on their physical properties. (author)

Groundwater arsenic contamination affecting different geologic domains in India--a review: influence of geological setting, fluvial geomorphology and Quaternary stratigraphy.

Science.gov (United States)

Acharyya, Subhrangsu K; Shah, Babar A

2007-10-01

Arsenic contamination in groundwater is pervasive within lowland organic-rich Bengal Delta and narrow entrenched channels in the Middle Ganga floodplains. Local areas of Damodar fan-delta and isolated areas within the Dongargarh Proterozoic rift-zone in central India are also contaminated. In this rift-zone, arsenic is enriched in felsic magmatic rocks and weathered rocks and soils from local areas are enriched further in arsenic and iron. Late Quaternary stratigraphy, geomorphology and sedimentation have influenced groundwater arsenic contamination in alluvium that aggraded during the Holocene sea-level rise. No specific source of arsenic could be identified, although Himalaya is the main provenance for the Ganga floodplain and the Bengal Delta. Gondwana coal seams and other Peninsular Indian rocks might be sources for arsenic in the Damodar fan-delta. As-bearing pyrite or any As-mineral is nearly absent in the aquifer sediments. Arsenic mainly occurs adsorbed on hydrated-iron-oxide (HFO), which coat sediment grains and minerals. Arsenic and iron are released to groundwater by bio-mediated reductive dissolution of HFO with corresponding oxidation of organic matter.

Risk assessment for pesticide contamination of groundwater with sparse available data

Science.gov (United States)

Bardowicks, K.; Heredia, O.; Billib, M.; Fernández Cirelli, A.; Boochs, P.

2009-04-01

The contamination of the water resources by agrochemicals is recognized in industrial countries as a very important environmental problem, nevertheless in most of developing and threshold countries the risks for health and environmental problems are not considered. In these countries agrochemicals, which are forbidden since several years in Europe (e.g. atrazine), are still in use. In some threshold countries monitoring systems are already installed for nutrients (N, P) and also a few for heavy metals, but so far the contamination by pesticides is hardly ever controlled, thus there is no data available about pesticide concentrations in soil and water. The aim of this research is to develop a methodology to show farmers and other water users (water agencies, drinking water supply companies) in basins of developing or threshold countries with sparse available data the risk of contamination of the groundwater resources by pesticides. A few data like pesticide application, precipitation, irrigation, potential evaporation and soil types are available in some regions. If these data is reliable it can be used together with some justified estimated parameters to perform simulations of the fate of pesticides to the groundwater. Therefore in two study cases in Argentina and Chile pesticide models (e.g. PESTAN, IPTM-CS) were used to evaluate the risk of contamination of the groundwater. The results were compared with contamination indicators, like one developed by O. Heredia, for checking their plausibility. Afterwards the results of the models were used as input data for simulations at the catchment scale, for instance for a groundwater simulation model (VISUAL MODFLOW). The results show a great risk for the contamination of the groundwater resources in the selected study areas, especially by atrazine. On this account the findings will be used by local researchers to improve the knowledge and the awareness of farmers and other stakeholders about the contamination of the

Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado

International Nuclear Information System (INIS)

1994-04-01

This report evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy's (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells to determine the potential for immediate human health and environmental impacts. This risk assessment evaluates the most contaminated groundwater that flows beneath the processing site towards the Gunnison River. The monitor wells that have consistently shown the highest concentration of most contaminants are used in this risk assessment. This risk assessment will be used in conjunction with additional activities and documents to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium

Modeling the effects of atmospheric emissions on groundwater composition

International Nuclear Information System (INIS)

Brown, T.J.

1994-01-01

A composite model of atmospheric, unsaturated and groundwater transport is developed to evaluate the processes determining the distribution of atmospherically derived contaminants in groundwater systems and to test the sensitivity of simulated contaminant concentrations to input parameters and model linkages. One application is to screen specific atmospheric emissions for their potential in determining groundwater age. Temporal changes in atmospheric emissions could provide a recognizable pattern in the groundwater system. The model also provides a way for quantifying the significance of uncertainties in the tracer source term and transport parameters on the contaminant distribution in the groundwater system, an essential step in using the distribution of contaminants from local, point source atmospheric emissions to examine conceptual models of groundwater flow and transport

Evaluation of the sources of contamination in the suburban area of Koropi-Markopoulo, Athens, Greece.

Science.gov (United States)

Kaitantzian, Agavni; Kelepertzis, Efstratios; Kelepertsis, Akindynos

2013-07-01

Heavy metal concentrations were monitored in agricultural soils and irrigation groundwaters of Koropi-Markopoulo area, a representative agricultural suburb in Athens, Greece, aiming at the identification of the sources of contaminants. Multivariate analyses of geochemical data demonstrated that agricultural practices and industrial activities considerably affected the quality of both environmental compartments. The levels of Ni, Cr, Co, Mn and Fe in agricultural soils were associated with geological parent materials whereas Pb, Zn and Cu mainly originated from anthropic activities. Referring to groundwaters, individual major anions and cations (K⁺, Na⁺, Ca²⁺, Mg²⁺, NO₃⁻, SO₄²⁻, Cl⁻) were influenced by various natural and anthropogenic factors whereas Ni, Cr, Cu and Zn were controlled by industrial and agronomic activities. The identification of the sources of contaminants in soil and groundwater environments is a valuable basis for encouraging mitigation strategies preventing further quality degradation.

Nitrate source identification in groundwater of multiple land-use areas by combining isotopes and multivariate statistical analysis: A case study of Asopos basin (Central Greece).

Science.gov (United States)

Matiatos, Ioannis

2016-01-15

Nitrate (NO3) is one of the most common contaminants in aquatic environments and groundwater. Nitrate concentrations and environmental isotope data (δ(15)N-NO3 and δ(18)O-NO3) from groundwater of Asopos basin, which has different land-use types, i.e., a large number of industries (e.g., textile, metal processing, food, fertilizers, paint), urban and agricultural areas and livestock breeding facilities, were analyzed to identify the nitrate sources of water contamination and N-biogeochemical transformations. A Bayesian isotope mixing model (SIAR) and multivariate statistical analysis of hydrochemical data were used to estimate the proportional contribution of different NO3 sources and to identify the dominant factors controlling the nitrate content of the groundwater in the region. The comparison of SIAR and Principal Component Analysis showed that wastes originating from urban and industrial zones of the basin are mainly responsible for nitrate contamination of groundwater in these areas. Agricultural fertilizers and manure likely contribute to groundwater contamination away from urban fabric and industrial land-use areas. Soil contribution to nitrate contamination due to organic matter is higher in the south-western part of the area far from the industries and the urban settlements. The present study aims to highlight the use of environmental isotopes combined with multivariate statistical analysis in locating sources of nitrate contamination in groundwater leading to a more effective planning of environmental measures and remediation strategies in river basins and water bodies as defined by the European Water Frame Directive (Directive 2000/60/EC).

Geogenic fluoride and arsenic contamination in the groundwater environments in Tanzania

Science.gov (United States)

Bhattacharya, Prosun; Lesafi, Fina; Filemon, Regina; Ligate, Fanuel; Ijumulana, Julian; Mtalo, Felix

2016-04-01

Adequate, safe and accessible drinking water is an important aspect to human health worldwide. Understanding this importance, the Tanzanian Government has initiated a number of programmes to ensure access to high quality water by the citizens. However, elevated concentration of geochemical pollutants in many drinking water sources pose a serious challenge to water suppliers and users in the country. Fluoride is a widespread drinking water contaminant of geogenic origin occuring in both surface- and groundwater around volcanic mountains and many parts within the East African Rift Valley in regions including Arusha (10 mg/L), Shinyanga (2.9 mg/L) and Singida (1.8 mg/L). An estimated 90% of the population living along the Rift Valley region are affected by dental or skeletal fluorosis and bone crippling because of long term exposure to very high levels of fluoride in drinking water sources. In the mining areas within Lake Victoria basin, groundwater wit elevated concentrations of arsenic has been discovered over an extended area. Most of these geochemical and naturally occurring drinking water pollutants are patchy with uncertainities in their spatial and temporal distribution patterns. The adverse health effects of skin disorder and cancer due to an elevated As concentration are reported from the North Mara gold and Geita mining areas in the Lake Victoria basin. About 30% of the water sources used for drinking in Tanzania exceed the WHO guideline values of fluoride (1.5 mg/L) and arsenic (10 μg/L). There is a scarcity of baseline information on the water quality data especially on geogenic contaminants in the groundwater and surface water as potable sources. This information is crucial in exploring sources of safe drinking water aquifers, associated human health risks of fluoride and arsenic pollution. using Laboratory based studies during the past two decades have shown promising results on the removal of fluoride and arsenic using locally available adsorbent

GWSCREEN: A Semi-analytical Model for Assessment of the Groundwater Pathway from Surface or Buried Contamination, Theory and User's Manual, Version 2.5

Energy Technology Data Exchange (ETDEWEB)

Rood, Arthur South

1998-08-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non-radioactive substances from surface or buried sources. The code was designed for implementation in the Track I and Track II assessment of Comprehensive Environmental Response, Compensation, and Liability Act sites identified as low probability hazard at the Idaho National Engineering Laboratory. The code calculates 1) the limiting soil concentration such that, after leaching and transport to the aquifer regulatory contaminant levels in groundwater are not exceeded, 2) peak aquifer concentration and associated human health impacts, and 3) aquifer concentrations and associated human health impacts as a function of time and space. The code uses a mass conservation approach to model three processes: contaminant release from a source volume, vertical contaminant transport in the unsaturated zone, and 2D or 3D contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. In Version 2.5, transport in the unsaturated zone is described by a plug flow or dispersive solution model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation in groundwater. Three source models are included; leaching from a surface or buried source, infiltration pond, or user-defined arbitrary release. Dispersion in the aquifer may be described by fixed dispersivity values or three, spatial-variable dispersivity functions. Version 2.5 also includes a Monte Carlo sampling routine for uncertainty/sensitivity analysis and a preprocessor to allow multiple input files and multiple contaminants to be run in a single simulation. GWSCREEN has been validated against other codes using similar algorithms and techniques. The code was originally designed for assessment and screening of the groundwater pathway when field data are limited. It was intended to simulate relatively simple

Arsenic Contamination of Groundwater in Nepal—An Overview

Directory of Open Access Journals (Sweden)

Sudhir Kumar Singh

2010-12-01

Full Text Available In Nepal, arsenic (As contamination is a major issue of current drinking water supply systems using groundwater and has recently been one of the major environmental health management issues especially in the plain region, i.e., in the Terai districts, where the population density is very high. The Terai inhabitants still use hand tube and dug wells (with hand held pumps that are bored at shallow to medium depth for their daily water requirements, including drinking water. The National Sanitation Steering Committee (NSSC, with the help of many other organizations, has completed arsenic blanket test in 25 districts of Nepal by analysing 737,009 groundwater samples. Several organizations, including academic institutions, made an effort to determine the levels of arsenic concentrations in groundwater and their consequences in Nepal. The results of the analyses on 25,058 samples tested in 20 districts, published in the status report of arsenic in Nepal (2003, demonstrated that the 23% of the samples were containing 10–50 µg/L of As, and the 8% of the samples were containing more than 50 µg/L of As. Recent status of over 737,009 samples tested, the 7.9% and 2.3% were contaminated by 10–50 µg/L and >50 µg/L, respectively of As. The present paper examines the various techniques available for the reduction of arsenic concentrations in Nepal in combination with the main results achieved, the socio-economic status and the strategies. This paper aims to comprehensively compile all existing data sets and analyze them scientifically, by trying to suggest a common sustainable approach for identifying the As contamination in the nation, that can be easily adopted by local communities for developing a sustainable society. The paper aims also to find probable solutions to quantify and mitigate As problem without any external support. The outcome of this paper will ultimately help to identify various ways for: identify risk areas; develop awareness; adopt

Modeling In Situ Bioremediation of Perchlorate-Contaminated Groundwater

National Research Council Canada - National Science Library

Secody, Roland E

2007-01-01

.... An innovative technology was recently developed which uses dual-screened treatment wells to mix an electron donor into perchlorate-contaminated groundwater in order to effect in situ bioremediation...

In Situ Monitoring of Groundwater Contamination Using the Kalman Filter For Sustainable Remediation

Science.gov (United States)

Schmidt, F.; Wainwright, H. M.; Faybishenko, B.; Denham, M. E.; Eddy-Dilek, C. A.

2017-12-01

Sustainable remediation - based on less intensive passive remediation and natural attenuation - has become a desirable remediation alternative at contaminated sites. Although it has a number of benefits, such as reduced waste and water/energy usage, it carries a significant burden of proof to verify plume stability and to ensure insignificant increase of risk to public health. Modeling of contaminant transport is still challenging despite recent advances in numerical methods. Long-term monitoring has, therefore, become a critical component in sustainable remediation. However, the current approach, which relies on sparse groundwater sampling, is problematic, since it could miss sudden significant changes in plume behavior. A new method is needed to combine existing knowledge about contaminant behavior and latest advances in in situ groundwater sensors. This study presents an example of the effective use of the Kalman filter approach to estimate contaminant concentrations, based on in situ measured water quality parameters (e.g. electrical conductivity and pH) along with the results of sparse groundwater sampling. The Kalman filter can effectively couple physical models and data correlations between the contaminant concentrations and in situ measured variables. We aim (1) to develop a framework capable of integrating different data types to provide accurate contaminant concentration estimates, (2) to demonstrate that these results remain reliable, even when the groundwater sampling frequency is reduced, and (3) to evaluate the future efficacy of this strategy using reactive transport simulations. This framework can also serve as an early warning system for detecting unexpected plume migration. We demonstrate our approach using historical and current groundwater data from the Savannah River Site (SRS) F-Area Seepage Basins to estimate uranium and tritium concentrations. The results show that the developed method can provide reliable estimates of contaminant

MALDI-TOF MS for the Identification of Cultivable Organic-Degrading Bacteria in Contaminated Groundwater near Unconventional Natural Gas Extraction Sites

Directory of Open Access Journals (Sweden)

Inês C. Santos

2017-08-01

Full Text Available Groundwater quality and quantity is of extreme importance as it is a source of drinking water in the United States. One major concern has emerged due to the possible contamination of groundwater from unconventional oil and natural gas extraction activities. Recent studies have been performed to understand if these activities are causing groundwater contamination, particularly with respect to exogenous hydrocarbons and volatile organic compounds. The impact of contaminants on microbial ecology is an area to be explored as alternatives for water treatment are necessary. In this work, we identified cultivable organic-degrading bacteria in groundwater in close proximity to unconventional natural gas extraction. Pseudomonas stutzeri and Acinetobacter haemolyticus were identified using matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF MS, which proved to be a simple, fast, and reliable method. Additionally, the potential use of the identified bacteria in water and/or wastewater bioremediation was studied by determining the ability of these microorganisms to degrade toluene and chloroform. In fact, these bacteria can be potentially applied for in situ bioremediation of contaminated water and wastewater treatment, as they were able to degrade both compounds.

MALDI-TOF MS for the Identification of Cultivable Organic-Degrading Bacteria in Contaminated Groundwater near Unconventional Natural Gas Extraction Sites.

Science.gov (United States)

Santos, Inês C; Martin, Misty S; Carlton, Doug D; Amorim, Catarina L; Castro, Paula M L; Hildenbrand, Zacariah L; Schug, Kevin A

2017-08-10

Groundwater quality and quantity is of extreme importance as it is a source of drinking water in the United States. One major concern has emerged due to the possible contamination of groundwater from unconventional oil and natural gas extraction activities. Recent studies have been performed to understand if these activities are causing groundwater contamination, particularly with respect to exogenous hydrocarbons and volatile organic compounds. The impact of contaminants on microbial ecology is an area to be explored as alternatives for water treatment are necessary. In this work, we identified cultivable organic-degrading bacteria in groundwater in close proximity to unconventional natural gas extraction. Pseudomonas stutzeri and Acinetobacter haemolyticus were identified using matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF MS), which proved to be a simple, fast, and reliable method. Additionally, the potential use of the identified bacteria in water and/or wastewater bioremediation was studied by determining the ability of these microorganisms to degrade toluene and chloroform. In fact, these bacteria can be potentially applied for in situ bioremediation of contaminated water and wastewater treatment, as they were able to degrade both compounds.

Using artificial sweeteners to identify contamination sources and infiltration zones in a coupled river-aquifer system

Science.gov (United States)

Bichler, Andrea; Muellegger, Christian; Hofmann, Thilo

2014-05-01

In shallow or unconfined aquifers the infiltration of contaminated river water might be a major threat to groundwater quality. Thus, the identification of possible contamination sources in coupled surface- and groundwater systems is of paramount importance to ensure water quality. Micropollutants like artificial sweeteners are promising markers for domestic waste water in natural water bodies. Compounds, such as artificial sweeteners, might enter the aquatic environment via discharge of waste water treatment plants, leaky sewer systems or septic tanks and are ubiquitously found in waste water receiving waters. The hereby presented field study aims at the (1) identification of contamination sources and (2) delineation of infiltration zones in a connected river-aquifer system. River bank filtrate in the groundwater body was assessed qualitatively and quantitatively using a combined approach of hydrochemical analysis and artificial sweeteners (acesulfame ACE) as waste water markers. The investigated aquifer lies within a mesoscale alpine head water catchment and is used for drinking water production. It is hypothesized that a large proportion of the groundwater flux originates from bank filtrate of a nearby losing stream. Water sampling campaigns in March and July 2012 confirmed the occurrence of artificial sweeteners at the investigated site. The municipal waste water treatment plant was identified as point-source for ACE in the river network. In the aquifer ACE was present in more than 80% of the monitoring wells. In addition, water samples were classified according to their hydrochemical composition, identifying two predominant types of water in the aquifer: (1) groundwater influenced by bank filtrate and (2) groundwater originating from local recharge. In combination with ACE concentrations a third type of water could be discriminated: (3) groundwater influence by bank filtrate but infiltrated prior to the waste water treatment plant. Moreover, the presence of ACE

Resolving superimposed ground-water contaminant plumes characterized by chromium, nitrate, uranium, and technetium--99

International Nuclear Information System (INIS)

Hall, S.H.

1990-02-01

Leakage from a liquid waste storage and solar evaporation basin at the Hanford Site in southeastern Washington State has resulted in a ground-water contaminant plume characterized by nitrate, hexavalent chromium, uranium, and technetium-99. The plume is superimposed on a larger, pre-existing plume extending from upgradient sites and having the same suite of contaminants. However, the relative abundance of contaminant species is quite different for each plume source. Thus, characteristic concentration ratios, rather than concentrations of individual species, are used as geochemical tracers, with emphasis on graphical analysis. Accordingly, it has been possible to resolve the boundaries of the smaller plume and to estimate the contribution of each plume to the observed contamination downgradient from the storage basin. 11 refs., 7 figs

Groundwater-derived contaminant fluxes along a channelized Coastal Plain stream

Energy Technology Data Exchange (ETDEWEB)

LaSage, Danita m [JL Sexton and Son; Fryar, Alan E [Dept of Earth and Geoligical Sciences, Univ of KY,; Mukherjee, Abhijit [Univ of Tx, Jackson School of Geosciences, Bur of Econ. Geology; Sturchio, Neil C [Dept of earth and Env. Sciences, Univ of Ill at Chicago; Heraty, Linnea J [Dept of earth and Env. Sciences, Univ of Ill at Chicago

2008-10-01

Recent studies in various settings across eastern North America have examined the movement of volatile organic compound (VOC) plumes from groundwater to streams, but few studies have addressed focused discharge of such plumes in unlithified sediments. From 1999 through 2002, we monitored concentrations of trichloroethene (TCE) and the non-volatile co-contaminant technetium-99 along Little Bayou Creek, a first -order perennial stream in the Coastal Plain of western Kentucky. Spring flow contributed TCE and technetium-99 to the creek, and TCE concentrations tended to vary with technetium-99 in springs. Contaminant concentrations in stream water fluctuated seasonally, but not always synchronously with stream flow. However, contaminant influxes varied seasonally with stream flow and were dominated by a few springs. Concentrations of O₂, NO₃⁻, and SO^2-₄, values of δ³⁷CL in groundwater, and the lack of less-chlorinated ethenes in groundwater and stream water indicated that aerobic biodegradation of TCE was unlikely. Losses of TCE along Little Bayou Creek resulted mainly from volatilization, in contrast to streams receiving diffuse contaminated discharge, where intrinsic bioremediation of VOCs appears to be prevalent.

Pollution potential of oil-contaminated soil on groundwater resources in Kuwait

International Nuclear Information System (INIS)

Literathy, P.; Quinn, M.; Al-Rashed, M.

2003-01-01

The only natural freshwater resource of Kuwait occurs as lenses floating on the saline groundwater in the northern part of the country, near to the oil fields. Rainwater is the only means of recharge of this limited groundwater resource. This groundwater is used as bottled drinking water and the fresh groundwater aquifer is considered as a strategic drinking water reserve for Kuwait. As a result of the 1991 Gulf War, the upper soil layer has been widely contaminated with crude oil and crude oil combustion products, which are potential pollutants likely affecting the groundwater resources. Significant efforts have been made to assess this pollution. These included: (a) a soil survey for assessing the soil contamination, and (b) leaching experiments to characterise the mobilization of the soil-associated pollutants. Fluorescence measurement techniques were used during field surveys as well as for laboratory testing. In addition, determination of the total extractable matter (TEM), total petroleum hydrocarbons (TPH), and GC/MS measurement of polyaromatic hydrocarbons (PAHs) were performed for the assessments. The laser induced fluorescence (LIF) measurement, having good correlation with the other laboratory measurements, was proved to provide necessary information for the assessment of the oil-contamination level in the desert soil. The subsequent leaching test with water demonstrated the mobilization of the fluorescing compounds (e.g. PAHs), and the alteration in the leaching characteristics of the contamination during the long term environmental weathering of the oil. (author)

Nitrate source identification in groundwater of multiple land-use areas by combining isotopes and multivariate statistical analysis: A case study of Asopos basin (Central Greece)

International Nuclear Information System (INIS)

Matiatos, Ioannis

2016-01-01

Nitrate (NO_3) is one of the most common contaminants in aquatic environments and groundwater. Nitrate concentrations and environmental isotope data (δ"1"5N–NO_3 and δ"1"8O–NO_3) from groundwater of Asopos basin, which has different land-use types, i.e., a large number of industries (e.g., textile, metal processing, food, fertilizers, paint), urban and agricultural areas and livestock breeding facilities, were analyzed to identify the nitrate sources of water contamination and N-biogeochemical transformations. A Bayesian isotope mixing model (SIAR) and multivariate statistical analysis of hydrochemical data were used to estimate the proportional contribution of different NO_3 sources and to identify the dominant factors controlling the nitrate content of the groundwater in the region. The comparison of SIAR and Principal Component Analysis showed that wastes originating from urban and industrial zones of the basin are mainly responsible for nitrate contamination of groundwater in these areas. Agricultural fertilizers and manure likely contribute to groundwater contamination away from urban fabric and industrial land-use areas. Soil contribution to nitrate contamination due to organic matter is higher in the south-western part of the area far from the industries and the urban settlements. The present study aims to highlight the use of environmental isotopes combined with multivariate statistical analysis in locating sources of nitrate contamination in groundwater leading to a more effective planning of environmental measures and remediation strategies in river basins and water bodies as defined by the European Water Frame Directive (Directive 2000/60/EC). - Highlights: • More enriched N-isotope values were observed in the industrial/urban areas. • A Bayesian isotope mixing model was applied in a multiple land-use area. • A 3-component model explained the factors controlling nitrate content in groundwater. • Industrial/urban nitrogen source was

Nitrate source identification in groundwater of multiple land-use areas by combining isotopes and multivariate statistical analysis: A case study of Asopos basin (Central Greece)

Energy Technology Data Exchange (ETDEWEB)

Matiatos, Ioannis, E-mail: i.matiatos@iaea.org

2016-01-15

Nitrate (NO{sub 3}) is one of the most common contaminants in aquatic environments and groundwater. Nitrate concentrations and environmental isotope data (δ{sup 15}N–NO{sub 3} and δ{sup 18}O–NO{sub 3}) from groundwater of Asopos basin, which has different land-use types, i.e., a large number of industries (e.g., textile, metal processing, food, fertilizers, paint), urban and agricultural areas and livestock breeding facilities, were analyzed to identify the nitrate sources of water contamination and N-biogeochemical transformations. A Bayesian isotope mixing model (SIAR) and multivariate statistical analysis of hydrochemical data were used to estimate the proportional contribution of different NO{sub 3} sources and to identify the dominant factors controlling the nitrate content of the groundwater in the region. The comparison of SIAR and Principal Component Analysis showed that wastes originating from urban and industrial zones of the basin are mainly responsible for nitrate contamination of groundwater in these areas. Agricultural fertilizers and manure likely contribute to groundwater contamination away from urban fabric and industrial land-use areas. Soil contribution to nitrate contamination due to organic matter is higher in the south-western part of the area far from the industries and the urban settlements. The present study aims to highlight the use of environmental isotopes combined with multivariate statistical analysis in locating sources of nitrate contamination in groundwater leading to a more effective planning of environmental measures and remediation strategies in river basins and water bodies as defined by the European Water Frame Directive (Directive 2000/60/EC). - Highlights: • More enriched N-isotope values were observed in the industrial/urban areas. • A Bayesian isotope mixing model was applied in a multiple land-use area. • A 3-component model explained the factors controlling nitrate content in groundwater. • Industrial

Groundwater arsenic contamination in Bangladesh-21 Years of research.

Science.gov (United States)

Chakraborti, Dipankar; Rahman, Mohammad Mahmudur; Mukherjee, Amitava; Alauddin, Mohammad; Hassan, Manzurul; Dutta, Rathindra Nath; Pati, Shymapada; Mukherjee, Subhash Chandra; Roy, Shibtosh; Quamruzzman, Quazi; Rahman, Mahmuder; Morshed, Salim; Islam, Tanzima; Sorif, Shaharir; Selim, Md; Islam, Md Razaul; Hossain, Md Monower

2015-01-01

Department of Public Health Engineering (DPHE), Bangladesh first identified their groundwater arsenic contamination in 1993. But before the international arsenic conference in Dhaka in February 1998, the problem was not widely accepted. Even in the international arsenic conference in West-Bengal, India in February, 1995, representatives of international agencies in Bangladesh and Bangladesh government attended the conference but they denied the groundwater arsenic contamination in Bangladesh. School of Environmental Studies (SOES), Jadavpur University, Kolkata, India first identified arsenic patient in Bangladesh in 1992 and informed WHO, UNICEF of Bangladesh and Govt. of Bangladesh from April 1994 to August 1995. British Geological Survey (BGS) dug hand tube-wells in Bangladesh in 1980s and early 1990s but they did not test the water for arsenic. Again BGS came back to Bangladesh in 1992 to assess the quality of the water of the tube-wells they installed but they still did not test for arsenic when groundwater arsenic contamination and its health effects in West Bengal in Bengal delta was already published in WHO Bulletin in 1988. From December 1996, SOES in collaboration with Dhaka Community Hospital (DCH), Bangladesh started analyzing hand tube-wells for arsenic from all 64 districts in four geomorphologic regions of Bangladesh. So far over 54,000 tube-well water samples had been analyzed by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). From SOES water analysis data at present we could assess status of arsenic groundwater contamination in four geo-morphological regions of Bangladesh and location of possible arsenic safe groundwater. SOES and DCH also made some preliminary work with their medical team to identify patients suffering from arsenic related diseases. SOES further analyzed few thousands biological samples (hair, nail, urine and skin scales) and foodstuffs for arsenic to know arsenic body burden and people sub

California GAMA Program: Sources and transport of nitrate in shallow groundwater in the Llagas Basin of Santa Clara County, California

International Nuclear Information System (INIS)

Moran, J E; McNab, W; Esser, B; Hudson, G; Carle, S; Beller, H; Kane, S; Tompson, A B; Letain, T; Moore, K; Eaton, G; Leif, R; Moody-Bartel, C; Singleton, M

2005-01-01

A critical component of the State Water Resource Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) Program is to assess the major threats to groundwater resources that supply drinking water to Californians (Belitz et al., 2004). Nitrate is the most pervasive and intractable contaminant in California groundwater and is the focus of special studies under the GAMA program. This report presents results of a study of nitrate contamination in the aquifer beneath the cities of Morgan Hill and Gilroy, CA, in the Llagas Subbasin of Santa Clara County, where high nitrate levels affect several hundred private domestic wells. The main objectives of the study are: (1) to identify the main source(s) of nitrate that issue a flux to the shallow regional aquifer (2) to determine whether denitrification plays a role in the fate of nitrate in the subbasin and (3) to assess the impact that a nitrate management plan implemented by the local water agency has had on the flux of nitrate to the regional aquifer. Analyses of 56 well water samples for major anions and cations, nitrogen and oxygen isotopes of nitrate, dissolved excess nitrogen, tritium and groundwater age, and trace organic compounds, show that synthetic fertilizer is the most likely source of nitrate in highly contaminated wells, and that denitrification is not a significant process in the fate of nitrate in the subbasin except in the area of recycled water application. In addition to identifying contaminant sources, these methods offer a deeper understanding of how the severity and extent of contamination are affected by hydrogeology and groundwater management practices. In the Llagas subbasin, the nitrate problem is amplified in the shallow aquifer because it is highly vulnerable with high vertical recharge rates and rapid lateral transport, but the deeper aquifers are relatively more protected by laterally extensive aquitards. Artificial recharge delivers low-nitrate water and provides a means of long

Intrinsic bioremediation of diesel-contaminated cold groundwater in bedrock

International Nuclear Information System (INIS)

Cross, K.M.; Biggar, K.W.; Guigard, S.E.

2006-01-01

Natural attenuation refers to the natural process by which contaminants in groundwater or soil are reduced through a combination of physico-chemical processes and biodegradation by indigenous organisms. The physico chemical processes include advection, dilution, dispersion, sorption, volatilization and abiotic transformation. This study evaluated the historical contaminant and geochemical evidence of natural attenuation at a well site where groundwater had been contaminated by a diesel fuel leak in 1982. In particular, evidence of intrinsic bioremediation was evaluated. Evidence of microbial activity was determined by most probably number (MPN) and commercial biological activity reaction tests. Groundwater samples from the site were incubated in a laboratory under aerobic and anaerobic conditions with electron acceptor and nutrient amendment to assess microbial activity. Mineralization of carbon 14-dodecane was measured to determine aerobic biodegradation rates. Anaerobic biodegradation rates were calculated from the depletion of total extractable hydrocarbon over 717 days. Nutrient addition increased the anaerobic first-order biodegradation rate from 0.0005 to 0.0016 per day. It was suggested controlled nutrient addition can improve the current slow rates of intrinsic bioremediation. 33 refs., 9 tabs., 5 figs

Baseline risk assessment of groundwater contamination at the uranium mill tailings site near Shiprock, New Mexico

International Nuclear Information System (INIS)

1993-09-01

This report evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in a disposal cell on the site in 1986 by the US Department of Energy's (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This risk assessment is the first document specific to this site for the Groundwater Project. This risk assessment follows the approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the floodplain groundwater are arsenic, magnesium, manganese, nitrate, sodium, sulfate, and uranium. The complete list of contaminants associated with the terrace groundwater could not be determined due to the lack of the background groundwater quality data. However, uranium, nitrate, and sulfate are evaluated since these chemicals are clearly associated with uranium processing and are highly elevated compared to regional waters. It also could not be determined if the groundwater occurring in the terrace is a usable water resource, since it appears to have originated largely from past milling operations. The next step in the risk assessment is to estimate how much of these contaminants people would be exposed to if a drinking well were installed in the contaminated groundwater or if there were exposure to surface expressions of contaminated water. Potential exposures to surface water include incidental contact with contaminated water or sediments by children playing on the floodplain and consumption of meat and milk from domestic animals grazed and watered on the floodplain

Groundwater protection from cadmium contamination by permeable reactive barriers

Energy Technology Data Exchange (ETDEWEB)

Di Natale, F. [Dipartimento di Ingegneria chimica, Universita di Federico II, P.le Tecchio, 80-80125 Naples (Italy)], E-mail: fdinatal@unina.it; Di Natale, M.; Greco, R. [Centro Interdipartimentale di Ricerca in Ingegneria Ambientale (CIRIAM), Dipartimento di Ingegneria Civile, Seconda Universita di Napoli, via Roma 29-81031 Aversa (Caserta) (Italy); Lancia, A. [Dipartimento di Ingegneria chimica, Universita di Federico II, P.le Tecchio, 80-80125 Naples (Italy); Laudante, C.; Musmarra, D. [Centro Interdipartimentale di Ricerca in Ingegneria Ambientale (CIRIAM), Dipartimento di Ingegneria Civile, Seconda Universita di Napoli, via Roma 29-81031 Aversa (Caserta) (Italy)

2008-12-30

This work studies the reliability of an activated carbon permeable reactive barrier in removing cadmium from a contaminated shallow aquifer. Laboratory tests have been performed to characterize the equilibrium and kinetic adsorption properties of the activated carbon in cadmium-containing aqueous solutions. A 2D numerical model has been used to describe pollutant transport within a groundwater and the pollutant adsorption on the permeable adsorbing barrier (PRB). In particular, it has been considered the case of a permeable adsorbing barrier (PAB) used to protect a river from a Cd(II) contaminated groundwater. Numerical results show that the PAB can achieve a long-term efficiency by preventing river pollution for several months.

Costs of groundwater contamination

International Nuclear Information System (INIS)

O'Neil, W.B.; Raucher, R.S.

1990-01-01

Two factors determine the cost of groundwater contamination: (1) the ways in which water was being used or was expected to be used in the future and (2) the physical characteristics of the setting that constrain the responses available to regain lost uses or to prevent related damages to human health and the environment. Most contamination incidents can be managed at a low enough cost that uses will not be foreclosed. It is important to take into account the following when considering costs: (1) natural cleansing through recharge and dilution can take many years; (2) it is difficult and costly to identify the exact area and expected path of a contamination plume; and (3) treatment or replacement of contaminated water often may represent the cost-effective strategy for managing the event. The costs of contamination include adverse health effects, containment and remediation, treatment and replacement costs. In comparing the costs and benefits of prevention programs with those of remediation, replacement or treatment, it is essential to adjust the cost/benefit numbers by the probability of their actual occurrence. Better forecasts of water demand are needed to predict more accurately the scarcity of new supply and the associated cost of replacement. This research should include estimates of the price elasticity of water demand and the possible effect on demand of more rational cost-based pricing structures. Research and development of techniques for in situ remediation should be encouraged

Carbonate and carbon isotopic evolution of groundwater contaminated by produced water brine with hydrocarbons

International Nuclear Information System (INIS)

Atekwana, Eliot A.; Seeger, Eric J.

2015-01-01

The major ionic and dissolved inorganic carbon (DIC) concentrations and the stable carbon isotope composition of DIC (δ"1"3C_D_I_C) were measured in a freshwater aquifer contaminated by produced water brine with petroleum hydrocarbons. Our aim was to determine the effects of produced water brine contamination on the carbonate evolution of groundwater. The groundwater was characterized by three distinct anion facies: HCO_3"−-rich, SO_4"2"−-rich and Cl"−-rich. The HCO_3"−-rich groundwater is undergoing closed system carbonate evolution from soil CO_2_(_g_) and weathering of aquifer carbonates. The SO_4"2"−-rich groundwater evolves from gypsum induced dedolomitization and pyrite oxidation. The Cl"−-rich groundwater is contaminated by produced water brine and undergoes common ion induced carbonate precipitation. The δ"1"3C_D_I_C of the HCO_3"−-rich groundwater was controlled by nearly equal contribution of carbon from soil CO_2_(_g_) and the aquifer carbonates, such that the δ"1"3C of carbon added to the groundwater was −11.6‰. In the SO_4"2"−-rich groundwater, gypsum induced dedolomitization increased the "1"3C such that the δ"1"3C of carbon added to the groundwater was −9.4‰. In the produced water brine contaminated Cl"−-rich groundwater, common ion induced precipitation of calcite depleted the "1"3C such that the δ"1"3C of carbon added to the groundwater was −12.7‰. The results of this study demonstrate that produced water brine contamination of fresh groundwater in carbonate aquifers alters the carbonate and carbon isotopic evolution. - Highlights: • We studied carbonate and δ"1"3C evolution in groundwater contaminated by produced water brine. • Multiple processes affect the carbonate and δ"1"3C evolution of the groundwater. • The processes are carbonate weathering, dedolomitization and common ion induce calcite precipitation. • The δ"1"3C added to DIC was −11.6‰ for weathering, −9.4‰ for dedolomitization

Identification of nitrate sources in groundwater and potential impact on drinking water reservoir (Goczałkowice reservoir, Poland)

Science.gov (United States)

Czekaj, Joanna; Jakóbczyk-Karpierz, Sabina; Rubin, Hanna; Sitek, Sławomir; Witkowski, Andrzej J.

2016-08-01

Goczałkowice dammed reservoir (area - 26 km2) is a strategic object for flood control in the Upper Vistula River catchment and one of the most important source of drinking water in the Upper Silesian Industrial Region (Southern Poland). Main aims of the investigation were identification of sources of nitrate and assessment of their significance in potential risk to groundwater quality. In the catchment area monitoring network of 22 piezometers, included 14 nested, have been installed. The significant spatial and seasonal differences in chemical composition between northern and southern part of the catchment were indicated based on the groundwater sampling conducted twice - in autumn 2011 and spring 2012. Maximum observed concentrations of nitrate were identified in northern part of the study area 255 mg/L as a results of inappropriate sewage management and agriculture activity. Results, based on the combines multi-scale hydrogeological and hydrochemical field studies, groundwater flow and transport modelling, dual stable isotope approach and geochemical modelling indicate mainly agriculture and inappropriate sewage water management as a sources of NO3- contamination of groundwater which moreover is affected by geochemical processes. In general, contaminated groundwater does not impact surface water quality. However, due to high concentration of nitrate in northern part a continues measurements of nitrogen compounds should be continued and used for reducing uncertainty of the predictive scenarios of the mass transport modelling in the study area.

Arsenic Groundwater Contamination in Bengal: a Coupled Geochemical and Geophysical Study

Science.gov (United States)

Charlet, L.; Ansari, A. A.; Dietrich, M.; Latscha, A.; LeBeux, A.; Chatterjee, D.; Mallik, S. B.

2001-05-01

Arsenic contamination in drinking water is a problem of great concern in Ganges delta region, and could be one of the largest natural calamity in the world. In the present study, a contamination plume located in the Lalpur area (Chakdaha Block, Nadia District, West Bengal, India) was studied. A coupled geochemical and geophysical approach was employed to understand the mechanism of arsenic mobilisation from the sediments to groundwater, as a first step towards a global explanation of the phenomenon for other contaminated areas in the Ganges delta. The groundwater As concentration, in the 10 km x 10 km studied area, ranges from 10 to 500 ppb. In situ chemical speciation of arsenic was carried out and various geochemical parameters were measured in representative contaminated wells to interpret the mobilization mechanism in terms of redox kinetics. Through geophysical investigations, subsurface lithology, sediment depositional and geomorphological characteristics were determined and correlated with the arsenic contamination processes. From a geomorphological viewpoint, the contaminated area is located in an abandoned paleochannel of the Hooghly river, interpreted as the active site of deposition of fine sediments which were preserved as clay pockets at certain depths. These clay pockets are rich in organic matter, which may be the driving force for redox potential change and thus, may have driven the mobilisation of arsenic in groundwater. The clay pockets rich in organic matter presumably represent the major reservoir where arsenic is sitting and getting released due to redox mechanism. They are sampled at present. A piezometric depression cone characterized by a radial groundwater flow is located underneath the highly populated Lalpur area. The arsenic plume appears to migrate from the Hooghly river towards the cone of depression following the water flowpath, and this shall be verified in forthcoming field campaigns. As (III) constitutes 42 % of the total As

Field demonstration of ex situ biological treatability of contaminated groundwater at the Strachan gas plant

International Nuclear Information System (INIS)

Kurz, M.D.; Stepan, D.J.

1997-03-01

A multi-phase study was conducted to deal with the issues of groundwater and soil contamination by sour gas processing plants in Alberta. Phase One consisted of a review of all soil and groundwater monitoring data submitted to Alberta Environment by sour gas plants in accordance with the Canadian Clean Water Act. The current phase involves the development, evaluation and demonstration of selected remediation technologies to address subsurface contamination of sediments and groundwater at sour gas treatment plants with special attention to the presence of natural gas condensate in the subsurface. Results are presented from a pilot-scale biological treatability test that was performed at the Gulf Strachan Natural Gas Processing Plant in Rocky Mountain House, Alberta, where contaminated groundwater from the plant was being pumped to the surface through many recovery wells to control contaminant migration. The recovered groundwater was directed to a pump-and-treat system that consisted of oil-water separation, iron removal, hardness removal, and air stripping, before being reinjected. The pilot-scale biological treatability testing was conducted to evaluate process stability in treating groundwater without pretreatment for iron and hardness reduction and to evaluate the removal of organic contaminants. Results of a groundwater characterization analysis are discussed. Chemical characteristics of the groundwater at the Strachan Gas Plant showed that an ex situ remediation technology would address the dissolved volatile and semi-volatile organic contamination from natural gas condensates, as well as the nitrogenous compounds resulting from the use of amine-based process chemicals. 4 refs., 5 tabs., 4 figs

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Energy Technology Data Exchange (ETDEWEB)

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-03-01

The purpose of this work is to characterize groundwater flow and contaminant transport at the Shoal underground nuclear test through numerical modeling using site-specific hydrologic data. The ultimate objective is the development of a contaminant boundary, a model-predicted perimeter defining the extent of radionuclide-contaminated groundwater from the underground test throughout 1,000 years at a prescribed level of confidence. This boundary will be developed using the numerical models described here, after they are approved for that purpose by DOE and NDEP.

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

International Nuclear Information System (INIS)

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-01-01

The purpose of this work is to characterize groundwater flow and contaminant transport at the Shoal underground nuclear test through numerical modeling using site-specific hydrologic data. The ultimate objective is the development of a contaminant boundary, a model-predicted perimeter defining the extent of radionuclide-contaminated groundwater from the underground test throughout 1,000 years at a prescribed level of confidence. This boundary will be developed using the numerical models described here, after they are approved for that purpose by DOE and NDEP

Predicting redox-sensitive contaminant concentrations in groundwater using random forest classification

Science.gov (United States)

Tesoriero, Anthony J.; Gronberg, Jo Ann; Juckem, Paul F.; Miller, Matthew P.; Austin, Brian P.

2017-08-01

Machine learning techniques were applied to a large (n > 10,000) compliance monitoring database to predict the occurrence of several redox-active constituents in groundwater across a large watershed. Specifically, random forest classification was used to determine the probabilities of detecting elevated concentrations of nitrate, iron, and arsenic in the Fox, Wolf, Peshtigo, and surrounding watersheds in northeastern Wisconsin. Random forest classification is well suited to describe the nonlinear relationships observed among several explanatory variables and the predicted probabilities of elevated concentrations of nitrate, iron, and arsenic. Maps of the probability of elevated nitrate, iron, and arsenic can be used to assess groundwater vulnerability and the vulnerability of streams to contaminants derived from groundwater. Processes responsible for elevated concentrations are elucidated using partial dependence plots. For example, an increase in the probability of elevated iron and arsenic occurred when well depths coincided with the glacial/bedrock interface, suggesting a bedrock source for these constituents. Furthermore, groundwater in contact with Ordovician bedrock has a higher likelihood of elevated iron concentrations, which supports the hypothesis that groundwater liberates iron from a sulfide-bearing secondary cement horizon of Ordovician age. Application of machine learning techniques to existing compliance monitoring data offers an opportunity to broadly assess aquifer and stream vulnerability at regional and national scales and to better understand geochemical processes responsible for observed conditions.

Health risk assessment of drinking arsenic-containing groundwater in Hasilpur, Pakistan: effect of sampling area, depth, and source.

Science.gov (United States)

Tabassum, Riaz Ahmad; Shahid, Muhammad; Dumat, Camille; Niazi, Nabeel Khan; Khalid, Sana; Shah, Noor Samad; Imran, Muhammad; Khalid, Samina

2018-02-10

Currently, several news channels and research publications have highlighted the dilemma of arsenic (As)-contaminated groundwater in Pakistan. However, there is lack of data regarding groundwater As content of various areas in Pakistan. The present study evaluated As contamination and associated health risks in previously unexplored groundwater of Hasilpur-Pakistan. Total of 61 groundwater samples were collected from different areas (rural and urban), sources (electric pump, hand pump, and tubewell) and depths (35-430 ft or 11-131 m). The water samples were analyzed for As level and other parameters such as pH, electrical conductivity, total dissolved solids, cations, and anions. It was found that 41% (25 out of 61) water samples contained As (≥ 5 μg/L). Out of 25 As-contaminated water samples, 13 water samples exceeded the permissible level of WHO (10 μg/L). High As contents have been found in tubewell samples and at high sampling depths (> 300 ft). The major As-contaminated groundwater in Hasilpur is found in urban areas. Furthermore, health risk and cancer risk due to As contamination were also assessed with respect to average daily dose (ADD), hazard quotient (HQ), and carcinogenic risk (CR). The values of HQ and CR of As in Hasilpur were up to 58 and 0.00231, respectively. Multivariate analysis revealed a positive correlation between groundwater As contents, pH, and depth in Hasilpur. The current study proposed the proper monitoring and management of well water in Hasilpur to minimize the As-associated health hazards.

Modelling assessment of regional groundwater contamination due to historic smelter emissions of heavy metals

NARCIS (Netherlands)

Grift, B. van der; Griffioen, J.

2008-01-01

Historic emissions from ore smelters typically cause regional soil contamination. We developed a modelling approach to assess the impact of such contamination on groundwater and surface water load, coupling unsaturated zone leaching modelling with 3D groundwater transport modelling. Both historic

Multivariate statistical assessment of heavy metal pollution sources of groundwater around a lead and zinc plant

Directory of Open Access Journals (Sweden)

Zamani Abbas Ali

2012-12-01

Full Text Available Abstract The contamination of groundwater by heavy metal ions around a lead and zinc plant has been studied. As a case study groundwater contamination in Bonab Industrial Estate (Zanjan-Iran for iron, cobalt, nickel, copper, zinc, cadmium and lead content was investigated using differential pulse polarography (DPP. Although, cobalt, copper and zinc were found correspondingly in 47.8%, 100.0%, and 100.0% of the samples, they did not contain these metals above their maximum contaminant levels (MCLs. Cadmium was detected in 65.2% of the samples and 17.4% of them were polluted by this metal. All samples contained detectable levels of lead and iron with 8.7% and 13.0% of the samples higher than their MCLs. Nickel was also found in 78.3% of the samples, out of which 8.7% were polluted. In general, the results revealed the contamination of groundwater sources in the studied zone. The higher health risks are related to lead, nickel, and cadmium ions. Multivariate statistical techniques were applied for interpreting the experimental data and giving a description for the sources. The data analysis showed correlations and similarities between investigated heavy metals and helps to classify these ion groups. Cluster analysis identified five clusters among the studied heavy metals. Cluster 1 consisted of Pb, Cu, and cluster 3 included Cd, Fe; also each of the elements Zn, Co and Ni was located in groups with single member. The same results were obtained by factor analysis. Statistical investigations revealed that anthropogenic factors and notably lead and zinc plant and pedo-geochemical pollution sources are influencing water quality in the studied area.

Multivariate statistical assessment of heavy metal pollution sources of groundwater around a lead and zinc plant.

Science.gov (United States)

Zamani, Abbas Ali; Yaftian, Mohammad Reza; Parizanganeh, Abdolhossein

2012-12-17

The contamination of groundwater by heavy metal ions around a lead and zinc plant has been studied. As a case study groundwater contamination in Bonab Industrial Estate (Zanjan-Iran) for iron, cobalt, nickel, copper, zinc, cadmium and lead content was investigated using differential pulse polarography (DPP). Although, cobalt, copper and zinc were found correspondingly in 47.8%, 100.0%, and 100.0% of the samples, they did not contain these metals above their maximum contaminant levels (MCLs). Cadmium was detected in 65.2% of the samples and 17.4% of them were polluted by this metal. All samples contained detectable levels of lead and iron with 8.7% and 13.0% of the samples higher than their MCLs. Nickel was also found in 78.3% of the samples, out of which 8.7% were polluted. In general, the results revealed the contamination of groundwater sources in the studied zone. The higher health risks are related to lead, nickel, and cadmium ions. Multivariate statistical techniques were applied for interpreting the experimental data and giving a description for the sources. The data analysis showed correlations and similarities between investigated heavy metals and helps to classify these ion groups. Cluster analysis identified five clusters among the studied heavy metals. Cluster 1 consisted of Pb, Cu, and cluster 3 included Cd, Fe; also each of the elements Zn, Co and Ni was located in groups with single member. The same results were obtained by factor analysis. Statistical investigations revealed that anthropogenic factors and notably lead and zinc plant and pedo-geochemical pollution sources are influencing water quality in the studied area.

Suitability of artificial sweeteners as indicators of raw wastewater contamination in surface water and groundwater.

Science.gov (United States)

Tran, Ngoc Han; Hu, Jiangyong; Li, Jinhua; Ong, Say Leong

2014-01-01

There is no quantitative data on the occurrence of artificial sweeteners in the aquatic environment in Southeast Asian countries, particularly no information on their suitability as indicators of raw wastewater contamination on surface water and groundwater. This study provided the first quantitative information on the occurrence of artificial sweeteners in raw wastewater, surface water and groundwater in the urban catchment area in Singapore. Acesulfame, cyclamate, saccharin, and sucralose were ubiquitous in raw wastewater samples at concentrations in the range of ng/L-μg/L, while other sweeteners were not found or found only in a few of the raw wastewater samples. Residential and commercial effluents were demonstrated to be the two main sources of artificial sweeteners entering the municipal sewer systems. Relatively higher concentrations of the detected sweeteners were frequently found in surface waters at the sampling sites located in the residential/commercial areas. No significant difference in the concentrations of the detected sweeteners in surface water or groundwater was noted between wet and dry weather conditions (unpaired T-test, p> 0.05). Relatively higher concentrations and detection frequencies of acesulfame, cyclamate and saccharin in surface water samples were observed at the potentially impacted sampling sites, while these sweeteners were absent in most of the background surface water samples. Similarly, acesulfame, cyclamate, and saccharin were found in most groundwater samples at the monitoring well (GW6), which is located close to known leaking sewer segment; whereas these were absent in the background monitoring well, which is located in the catchment with no known wastewater sources. Taken together, the results suggest that acesulfame, cyclamate, and saccharin can be used as potential indicators of raw wastewater contamination in surface water and groundwater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stochastic Management of Non-Point Source Contamination: Joint Impact of Aquifer Heterogeneity and Well Characteristics

Science.gov (United States)

Henri, C. V.; Harter, T.

2017-12-01

Agricultural activities are recognized as the preeminent origin of non-point source (NPS) contamination of water bodies through the leakage of nitrate, salt and agrochemicals. A large fraction of world agricultural activities and therefore NPS contamination occurs over unconsolidated alluvial deposit basins offering soil composition and topography favorable to productive farming. These basins represent also important groundwater reservoirs. The over-exploitation of aquifers coupled with groundwater pollution by agriculture-related NPS contaminant has led to a rapid deterioration of the quality of these groundwater basins. The management of groundwater contamination from NPS is challenged by the inherent complexity of aquifers systems. Contaminant transport dynamics are highly uncertain due to the heterogeneity of hydraulic parameters controlling groundwater flow. Well characteristics are also key uncertain elements affecting pollutant transport and NPS management but quantifying uncertainty in NPS management under these conditions is not well documented. Our work focuses on better understanding the joint impact of aquifer heterogeneity and pumping well characteristics (extraction rate and depth) on (1) the transport of contaminants from NPS and (2) the spatio-temporal extension of the capture zone. To do so, we generate a series of geostatistically equivalent 3D heterogeneous aquifers and simulate the flow and non-reactive solute transport from NPS to extraction wells within a stochastic framework. The propagation of the uncertainty on the hydraulic conductivity field is systematically analyzed. A sensitivity analysis of the impact of extraction well characteristics (pumping rate and screen depth) is also conducted. Results highlight the significant role that heterogeneity and well characteristics plays on management metrics. We finally show that, in case of NPS contamination, the joint impact of regional longitudinal and transverse vertical hydraulic gradients and

Vertical contamination in the unconfined groundwater at the Hanford Site, Washington

International Nuclear Information System (INIS)

Eddy, P.A.; Myers, D.A.; Raymond, J.R.

1978-08-01

Disposal to the ground at Hanford of large volumes of low- and intermediate-level wastes in the local unconfined groundwater flow system has raised concern about the movement and distribution of this waste. Previous work produced information on the horizontal movement of the waste, but little or no information exists on its vertical distribution within the unconfined groundwater flow system. In 1975 Phase I of a study was started to determine the vertical distribution of contaminants in three existing wells (699-28-40, 699-31-31, and 699-37-43). Because of negative results, only one well that produced positive results (699-31-31) was chosen for Phase II. Phase II consisted of tests conducted on this well by a testing company, with samples cross-checked by two different laboratories. Phase III was a cooperative study with Rockwell Hanford Operations, which included the installation, testing, and sampling of piezometers. The data were then analyzed using predictive codes and models in order to determine if vertical movement did occur. The present groundwater flow system shows some vertical contamination. However, concentrations are relatively higher near the surface of the flow system, indicating possible radial flow patterns from the groundwater mounds known to have developed under the chemical processing area disposal sites. Upward flow from deeper aquifers may be diluting the contaminant and masking a possible downward migration of contaminants

Biochar- and phosphate-induced immobilization of heavy metals in contaminated soil and water: implication on simultaneous remediation of contaminated soil and groundwater.

Science.gov (United States)

Liang, Yuan; Cao, Xinde; Zhao, Ling; Arellano, Eduardo

2014-03-01

Long-term wastewater irrigation or solid waste disposal has resulted in the heavy metal contamination in both soil and groundwater. It is often separately implemented for remediation of contaminated soil or groundwater at a specific site. The main objective of this study was to demonstrate the hypothesis of simultaneous remediation of both heavy metal contaminated soil and groundwater by integrating the chemical immobilization and pump-and-treat methods. To accomplish the objective, three experiments were conducted, i.e., an incubation experiment was first conducted to determine how dairy-manure-derived biochar and phosphate rock tailing induced immobilization of Cd in the Cd-contaminated soils; second, a batch sorption experiment was carried out to determine whether the pre-amended contaminated soil still had the ability to retain Pb, Zn and Cd from aqueous solution. BCR sequential extraction as well as XRD and SEM analysis were conducted to explore the possible retention mechanism; and last, a laboratory-scale model test was undertaken by leaching the Pb, Zn, and Cd contaminated groundwater through the pre-amended contaminated soils to demonstrate how the heavy metals in both contaminated soil and groundwater were simultaneously retained and immobilized. The incubation experiment showed that the phosphate biochar were effective in immobilizing soil Cd with Cd concentration in TCLP (toxicity characteristics leaching procedure) extract reduced by 19.6 % and 13.7 %, respectively. The batch sorption experiment revealed that the pre-amended soil still had ability to retain Pb, Zn, and Cd from aqueous solution. The phosphate-induced metal retention was mainly due to the metal-phosphate precipitation, while both sorption and precipitation were responsible for the metal stabilization in the biochar amendment. The laboratory-scale test demonstrated that the soil amended with phosphate removed groundwater Pb, Zn, and Cd by 96.4 %, 44.6 %, and 49.2 %, respectively, and the

A Survey of 42 Semi-Volatile Organic Contaminants in Groundwater along the Grand Canal from Hangzhou to Beijing, East China

Directory of Open Access Journals (Sweden)

Xiaojie Li

2015-12-01

Full Text Available The status of organic pollution in groundwater in eastern China along the Grand Canal from Hangzhou to Beijing was evaluated. Forty-two semi-volatile organic contaminants were analyzed, including 16 polycyclic aromatic hydrocarbons (PAHs, seven polychlorinated biphenyls (PCBs, 12 organochlorine pesticides (OCPs and seven organophosphorus pesticides (OPPs. Among the detected contaminants, PAHs were the most widespread compounds. One PCB and six OCPs were detected in the groundwater samples, but none of the target OPPs was detected. The total concentration of the 16 PAHs ranged from 0.21 to 1006 ng/L, among which phenanthrene (271 ng/L and fluoranthene (233 ng/L were present at very high concentrations and naphthalene (32 positive detections in 50 samples and fluorene (28 detections in 50 samples were the most frequently detected. Benzo[a]pyrene equivalents indicated a high environmental risk related to PAHs in a few groundwater samples. To identify the possible sources of PAHs, three concentration ratios, low molecular weight PAHs/high molecular weight PAHs, anthracene/(anthracene + phenanthrene and fluoranthene/(fluoranthene + pyrene, were determined, that indicated that the PAHs mainly originated from mixed sources: pyrolytic and petrogenic sources with different ratios at different sites.

Behavioral response to contamination risk information in a spatially explicit groundwater environment: Experimental evidence

Science.gov (United States)

Li, Jingyuan; Michael, Holly A.; Duke, Joshua M.; Messer, Kent D.; Suter, Jordan F.

2014-08-01

This paper assesses the effectiveness of aquifer monitoring information in achieving more sustainable use of a groundwater resource in the absence of management policy. Groundwater user behavior in the face of an irreversible contamination threat is studied by applying methods of experimental economics to scenarios that combine a physics-based, spatially explicit, numerical groundwater model with different representations of information about an aquifer and its risk of contamination. The results suggest that the threat of catastrophic contamination affects pumping decisions: pumping is significantly reduced in experiments where contamination is possible compared to those where pumping cost is the only factor discouraging groundwater use. The level of information about the state of the aquifer also affects extraction behavior. Pumping rates differ when information that synthesizes data on aquifer conditions (a "risk gauge") is provided, despite invariant underlying economic incentives, and this result does not depend on whether the risk information is location-specific or from a whole aquifer perspective. Interestingly, users increase pumping when the risk gauge signals good aquifer status compared to a no-gauge treatment. When the gauge suggests impending contamination, however, pumping declines significantly, resulting in a lower probability of contamination. The study suggests that providing relatively simple aquifer condition guidance derived from monitoring data can lead to more sustainable use of groundwater resources.

Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado. Revision 1

Energy Technology Data Exchange (ETDEWEB)

1994-04-01

This report evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells to determine the potential for immediate human health and environmental impacts. This risk assessment evaluates the most contaminated groundwater that flows beneath the processing site towards the Gunnison River. The monitor wells that have consistently shown the highest concentration of most contaminants are used in this risk assessment. This risk assessment will be used in conjunction with additional activities and documents to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

To study the effects of groundwater contamination in Kasur due to Nallah Rohi

International Nuclear Information System (INIS)

Ghumman, A.R.; Shamim, M.A.

2005-01-01

Groundwater contamination is a worldwide known problem. Pakistan, being a developing country, is also facing the problem created by groundwater pollution. Disposal of domestic wastes and agricultural treatments has been reported to be a considerable factor for causing the pollution, especially the groundwater contamination. In the rural areas of Pakistan, latrines and septic tanks have become common because of the advancement in the living standards. All of the domestic wastes is disposed off into the ponds or nearby passing streams. In the similar fashion, drains in the big and well developed cities of Pakistan lead the domestic waste, along with the industrial waste, into the passing by streams, canals and rivers. All of such disposed off waste is untreated because of the lack of legislation and its improper implementation. The contaminated water affects the health of human beings and also destroys the crops when this water is used for irrigation. So this paper deals with the effects and condition of the disposal of the harmful chemicals, which ultimately through seepage reach the groundwater and make it hazardous. Also, the lateral distances of the contaminated groundwater were found out. For experimentation, major city of Kasur which is in the vicinity of Nullah Rohi, was selected. All the wastes including both the industrial as well as domestic, of the whole area, is disposed off into the Nullah. The percolation of the harmful chemicals and its mixing with groundwater has resulted in the hazardous effects on the inhabitants of the area on the irrigation land as well. So the water in the vicinity, at different locations was tested and the degree of contamination and the lateral distances of contaminated water were also worked out. (author)

Testing of a benchscale Reverse Osmosis/Coupled Transport system for treating contaminated groundwater

International Nuclear Information System (INIS)

Hodgson, K.M.; Lunsford, T.R.; Panjabi, G.

1994-01-01

The Reverse Osmosis/Coupled Transport process is a innovative means of removing radionuclides from contaminated groundwater at the Hanford Site. Specifically, groundwater in the 200 West Area of the Hanford Site has been contaminated with uranium, technetium, and nitrate. Investigations are proceeding to determine the most cost effective method to remove these contaminants. The process described in this paper combines three different membrane technologies (reverse osmosis, coupled transport, and nanofiltration to purify the groundwater while extracting and concentrating uranium, technetium, and nitrate into separate solutions. This separation allows for the future use of the radionuclides, if needed, and reduces the amount of waste that will need to be disposed of. This process has the potential to concentrate the contaminants into solutions with volumes in a ratio of 1/10,000 of the feed volume. This compares to traditional volume reductions of 10 to 100 for ion exchange and stand-alone reverse osmosis. The successful demonstration of this technology could result in significant savings in the overall cost of decontaminating the groundwater

Using Major Elements to Determine Sources of Nitrate in Groundwater, Suffolk County, Long Island, NY

Science.gov (United States)

Munster, J.; Hanson, G.; Bokuniewicz, H.

2004-05-01

Suffolk County is the eastern most county on Long Island with an area of 2,500 square kilometers and a population of 1.4 million. Groundwater is the only source of potable water for Suffolk County. Nitrate levels have become a concern as a result of the continued eastward urbanization of Long Island since the mid 1900's. In 2003, 2% of 1000 public supply wells had greater than 10 ppm nitrogen as nitrate, 8% had 6 to 10 ppm nitrogen as nitrate and 62% of the wells were rated as susceptible to increased nitrate contamination based on land use, travel time and prevalence. Nitrogen as nitrate above 10 ppm is harmful to infants and is currently the drinking water standard of the Environmental Protection Agency. The major sources of the nitrate in the urbanized areas are most likely turf grass fertilizer and sewage from septic tank/cesspool systems and sewage treatment plants that provide only secondary treatment. Turf grass occupies about 28% of the land. Two-thirds of the houses have septic tank/cesspool systems and a majority of the sewage treatment plants discharge effluent to the groundwater. Previous investigators of the sources of nitrate in groundwater on Long Island have used 15N values of nitrate-nitrogen to identify nitrate contamination (Bleifuss et al., 2000; Flipse and Bonner, 1985; Flipse et al., 1984; Kreitler et al., 1978). However, due to overlapping source signatures, nitrogen isotopes alone were not sufficient to characterize the sources of nitrate. More recent studies have shown that major elements that accompany nitrate in the groundwater (Bleifuss et al., 2000; Elhatip et al., 2003; Trauth and Xanthopoulos, 1997) may distinguish sources of nitrate with less ambiguity. In this study samples of waste water from septic tank/cesspool systems and sewage treatment plants and samples of soil water collected below turf grass that is not fertilized, fertilized with organic fertilizer and fertilized with chemical fertilizer were analyzed for major elements

Locating Groundwater Pathways of Anthropogenic Contaminants Using a Novel Approach in Kānéohe Watershed, Óahu, Hawaíi

Science.gov (United States)

McKenzie, T.; Dulai, H.; Popp, B. N.; Whittier, R. B.

2017-12-01

We have applied a novel approach using radon, δ15N and δ18O values of nitrate, and contaminants of emerging concern (CECs) to identify groundwater pathways of anthropogenic contaminants. This approach was applied in Kānéohe watershed, located on the windward side of Óahu, which has been subject to persistent near shore water pollution. Previous research has indicated that there are strong seasonal differences between surface runoff and groundwater discharge into Kānéohe Bay. Three sub-watersheds of varying land-use (e.g. cesspool density, agriculture, urbanization) bordering Kānéohe Bay were studied. Seasonality, as well as spatial and temporal variations of groundwater discharge into streams and the bay were captured by a series of snapshot studies using a natural isotope of radon as a tracer for groundwater inflow. δ15N and δ18O values of nitrate were used as source tracking tools to determine the potential origin (e.g. wastewater, agriculture) of nitrate. These results were paired with spatial analysis of land-use and further coupled with CEC concentrations in order to evaluate how land-use relates to stream and groundwater contaminant distribution. Previously unrecognized groundwater pathways for contaminant transport were identified using radon in conjunction with CEC and stable isotopic techniques. We present results for stream and coastal water quality, focusing on nutrient and CEC fluxes across the land-ocean interface, as well as discuss the application of CECs as novel wastewater tracers.

In Situ Treatment of Chlorinated Ethene-Contaminated Groundwater Using horizontal Flow Treatment Wells

National Research Council Canada - National Science Library

Ferland, Derek

2000-01-01

The limitations of conventional containment technologies for groundwater contaminated with chlorinated solvents have motivated development of innovative technologies to achieve national groundwater...

Baseline risk assessment of groundwater contamination at the uranium mill tailings site near Shiprock, New Mexico. Draft

Energy Technology Data Exchange (ETDEWEB)

1993-09-01

This report evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in a disposal cell on the site in 1986 by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This risk assessment is the first document specific to this site for the Groundwater Project. This risk assessment follows the approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the floodplain groundwater are arsenic, magnesium, manganese, nitrate, sodium, sulfate, and uranium. The complete list of contaminants associated with the terrace groundwater could not be determined due to the lack of the background groundwater quality data. However, uranium, nitrate, and sulfate are evaluated since these chemicals are clearly associated with uranium processing and are highly elevated compared to regional waters. It also could not be determined if the groundwater occurring in the terrace is a usable water resource, since it appears to have originated largely from past milling operations. The next step in the risk assessment is to estimate how much of these contaminants people would be exposed to if a drinking well were installed in the contaminated groundwater or if there were exposure to surface expressions of contaminated water. Potential exposures to surface water include incidental contact with contaminated water or sediments by children playing on the floodplain and consumption of meat and milk from domestic animals grazed and watered on the floodplain.

Groundwater fluoride contamination: A reappraisal

Directory of Open Access Journals (Sweden)

Amlan Banerjee

2015-03-01

Full Text Available Dissolution of fluorite (CaF2 and/or fluorapatite (FAP [Ca5(PO43F], pulled by calcite precipitation, is thought to be the dominant mechanism responsible for groundwater fluoride (F− contamination. Here, one dimensional reactive–transport models are developed to test this mechanism using the published dissolution and precipitation rate kinetics for the mineral pair FAP and calcite. Simulation results correctly show positive correlation between the aqueous concentrations of F− and CO32− and negative correlation between F− and Ca2+. Results also show that precipitation of calcite, contrary to the present understanding, slows down the FAP dissolution by 106 orders of magnitude compared to the FAP dissolution by hydrolysis. For appreciable amount of fluoride contamination rock–water interaction time must be long and of order 106 years.

Blast fracturing of bedrock to enhance recovery of contaminated groundwater

International Nuclear Information System (INIS)

Holzman, L.R.; Harvey, E.M.; McKee, R.C.E.; Katsabanis, T.

1992-01-01

Petroleum hydrocarbons releasd from a pipeline at a site in southern Ontario had contaminated a fractured dolostone bedrock aquifer. To remediate the site, contaminated groundwater was pumped from the downgradient edge of the hydrocarbon plume and injected into an upgradient area after treatment. Contaminant flow pathways in the fractured bedrock aquifer were found to be complex and erratic. It was anticipated that contaminated groundwater could escape the influence of a line of closely spaced recovery wells. In order to capture the migrating contaminants effectively, improve communication between recovery wells, and optimize pumping efficiencies, a rubble zone was created by drilling and blasting the rock. Using 140 blastholes, the bedrock was fractured to a depth of 4 m over a distance of 200 m. Similarly, an additional 80 blastholes were used to blast fracture 100 m of bedrock to a depth of 4 m in the recharge area to enhance injection of treated water to the aquifer. Various blasthole spacings and explosive loadings and patterns were tested to fracture the rock effectively while minimizing the impact on the nearby pipeline and neighboring residences. Vibrations were carefully monitored using several seismographs. Pump tests conducted before and after the blast indicated the hydraulic connection between the naturally occurring fractures had greatly improved. Monitoring conducted after startup of the pump-treat-and-inject system has confirmed the fracturing provides effective capture and injection of the groundwater. 3 refs., 3 figs., 1 tab

Groundwater contaminant plume ranking

International Nuclear Information System (INIS)

1988-08-01

Containment plumes at Uranium Mill Tailings Remedial Action (UMTRA) Project sites were ranked to assist in Subpart B (i.e., restoration requirements of 40 CFR Part 192) compliance strategies for each site, to prioritize aquifer restoration, and to budget future requests and allocations. The rankings roughly estimate hazards to the environment and human health, and thus assist in determining for which sites cleanup, if appropriate, will provide the greatest benefits for funds available. The rankings are based on the scores that were obtained using the US Department of Energy's (DOE) Modified Hazard Ranking System (MHRS). The MHRS and HRS consider and score three hazard modes for a site: migration, fire and explosion, and direct contact. The migration hazard mode score reflects the potential for harm to humans or the environment from migration of a hazardous substance off a site by groundwater, surface water, and air; it is a composite of separate scores for each of these routes. For ranking the containment plumes at UMTRA Project sites, it was assumed that each site had been remediated in compliance with the EPA standards and that relict contaminant plumes were present. Therefore, only the groundwater route was scored, and the surface water and air routes were not considered. Section 2.0 of this document describes the assumptions and procedures used to score the groundwater route, and Section 3.0 provides the resulting scores for each site. 40 tabs

Pathogens in Dairy Farming: Source Characterization and Groundwater Impacts

Science.gov (United States)

Atwill, E. R.; Watanabe, N.; Li, X.; Hou, L.; Harter, T.; Bergamaschi, B.

2007-12-01

Intense animal husbandry is of growing concern as a potential contamination source of enteric pathogens as well as antibiotics. To assess the public health risk from pathogens and their hydrologic pathways, we hypothesize that the animal farm is not a homogeneous diffuse source, but that pathogen loading to the soil and, therefore, to groundwater varies significantly between the various management units of a farm. A dairy farm, for example, may include an area with calf hutches, corrals for heifers of various ages, freestalls and exercise yards for milking cows, separate freestalls for dry cows, a hospital barn, a yard for collection of solid manure, a liquid manure storage lagoon, and fields receiving various amounts of liquid and solid manure. Pathogen shedding and, hence, therapeutic and preventive pharmaceutical treatments vary between these management units. We are implementing a field reconnaissance program to determine the occurrence of three different pathogens ( E. coli, Salmonella, Campylobacter) and one indicator organism ( Enterococcus) at the ground-surface and in shallow groundwater of seven different management units on each of two farms, and in each of four seasons (spring/dry season, summer/irrigation season, fall/dry season, winter/rainy season). Initial results indicate that significant differences exist in the occurrence of these pathogens between management units and between organisms. These differences are weakly reflected in their occurrence in groundwater, despite the similarity of the shallow geologic environment across these sites. Our results indicate the importance of differentiating sources within a dairy farm and the importance of understanding subsurface transport processes for these pathogens.

Seasonal and Spatial Variability of Anthropogenic and Natural Factors Influencing Groundwater Quality Based on Source Apportionment

Directory of Open Access Journals (Sweden)

Xueru Guo

2018-02-01

Full Text Available Globally, groundwater resources are being deteriorated by rapid social development. Thus, there is an urgent need to assess the combined impacts of natural and enhanced anthropogenic sources on groundwater chemistry. The aim of this study was to identify seasonal characteristics and spatial variations in anthropogenic and natural effects, to improve the understanding of major hydrogeochemical processes based on source apportionment. 34 groundwater points located in a riverside groundwater resource area in northeast China were sampled during the wet and dry seasons in 2015. Using principal component analysis and factor analysis, 4 principal components (PCs were extracted from 16 groundwater parameters. Three of the PCs were water-rock interaction (PC1, geogenic Fe and Mn (PC2, and agricultural pollution (PC3. A remarkable difference (PC4 was organic pollution originating from negative anthropogenic effects during the wet season, and geogenic F enrichment during the dry season. Groundwater exploitation resulted in dramatic depression cone with higher hydraulic gradient around the water source area. It not only intensified dissolution of calcite, dolomite, gypsum, Fe, Mn and fluorine minerals, but also induced more surface water recharge for the water source area. The spatial distribution of the PCs also suggested the center of the study area was extremely vulnerable to contamination by Fe, Mn, COD, and F−.

Simulations of groundwater flow, transport, and age in Albuquerque, New Mexico, for a study of transport of anthropogenic and natural contaminants (TANC) to public-supply wells

Science.gov (United States)

Heywood, Charles E.

2013-01-01

Vulnerability to contamination from manmade and natural sources can be characterized by the groundwater-age distribution measured in a supply well and the associated implications for the source depths of the withdrawn water. Coupled groundwater flow and transport models were developed to simulate the transport of the geochemical age-tracers carbon-14, tritium, and three chlorofluorocarbon species to public-supply wells in Albuquerque, New Mexico. A separate, regional-scale simulation of transport of carbon-14 that used the flow-field computed by a previously documented regional groundwater flow model was calibrated and used to specify the initial concentrations of carbon-14 in the local-scale transport model. Observations of the concentrations of each of the five chemical species, in addition to water-level observations and measurements of intra-borehole flow within a public-supply well, were used to calibrate parameters of the local-scale groundwater flow and transport models. The calibrated groundwater flow model simulates the mixing of “young” groundwater, which entered the groundwater flow system after 1950 as recharge at the water table, with older resident groundwater that is more likely associated with natural contaminants. Complexity of the aquifer system in the zone of transport between the water table and public-supply well screens was simulated with a geostatistically generated stratigraphic realization based upon observed lithologic transitions at borehole control locations. Because effective porosity was simulated as spatially uniform, the simulated age tracers are more efficiently transported through the portions of the simulated aquifer with relatively higher simulated hydraulic conductivity. Non-pumping groundwater wells with long screens that connect aquifer intervals having different hydraulic heads can provide alternate pathways for contaminant transport that are faster than the advective transport through the aquifer material. Simulation of

Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis

International Nuclear Information System (INIS)

Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G.

2012-01-01

Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

Effects of natural and human factors on groundwater quality of basin-fill aquifers in the southwestern United States-conceptual models for selected contaminants

Science.gov (United States)

Bexfield, Laura M.; Thiros, Susan A.; Anning, David W.; Huntington, Jena M.; McKinney, Tim S.

2011-01-01

As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, the Southwest Principal Aquifers (SWPA) study is building a better understanding of the factors that affect water quality in basin-fill aquifers in the Southwestern United States. The SWPA study area includes four principal aquifers of the United States: the Basin and Range basin-fill aquifers in California, Nevada, Utah, and Arizona; the Rio Grande aquifer system in New Mexico and Colorado; and the California Coastal Basin and Central Valley aquifer systems in California. Similarities in the hydrogeology, land- and water-use practices, and water-quality issues for alluvial basins within the study area allow for regional analysis through synthesis of the baseline knowledge of groundwater-quality conditions in basins previously studied by the NAWQA Program. Resulting improvements in the understanding of the sources, movement, and fate of contaminants are assisting in the development of tools used to assess aquifer susceptibility and vulnerability.This report synthesizes previously published information about the groundwater systems and water quality of 15 information-rich basin-fill aquifers (SWPA case-study basins) into conceptual models of the primary natural and human factors commonly affecting groundwater quality with respect to selected contaminants, thereby helping to build a regional understanding of the susceptibility and vulnerability of basin-fill aquifers to those contaminants. Four relatively common contaminants (dissolved solids, nitrate, arsenic, and uranium) and two contaminant classes (volatile organic compounds (VOCs) and pesticide compounds) were investigated for sources and controls affecting their occurrence and distribution above specified levels of concern in groundwater of the case-study basins. Conceptual models of factors that are important to aquifer vulnerability with respect to those contaminants and contaminant classes were subsequently formed. The

Remediation of TCE-contaminated groundwater using nanocatalyst and bacteria.

Science.gov (United States)

Kang, Ser Ku; Seo, Hyunhee; Sun, Eunyoung; Kim, Inseon; Roh, Yul

2011-08-01

The objective of this study was to develop and evaluate the remediation of trichloroethene (TCE)-contaminated groundwater using both a nanocatalyst (bio-Zn-magnetite) and bacterium (similar to Clostridium quinii) in anoxic environments. Of the 7 nanocatalysts tested, bio-Zn-magnetite showed the highest TCE dechlorination efficiency, with an average of ca. 90% within 8 days in a batch experiment. The column tests confirmed that the application of bio-Zn-magnetite in combination with the bacterium achieved high degradation efficiency (ca. 90%) of TCE within 5 days compared to the nanocatalyst only, which degraded only 30% of the TCE. These results suggest that the application of a nanocatalyst and the bacterium have potential for the remediation of TCE-contaminated groundwater in subsurface environments.

Preliminary hydrogeologic assessment of a ground-water contamination area in Wolcott, Connecticut

Science.gov (United States)

Stone, J.R.; Casey, G.D.; Mondazzi, R.A.; Frick, T.W.

1997-01-01

Contamination of ground water by volatile organic compounds and inorganic constituents has been identified at a number of industrial sites in the Town of Wolcott, Connecticut. Contamination is also present at a municipal landfill in the City of Waterbury that is upgradient from the industrial sites in the local ground-water-flow system. The study area, which lies in the Western Highlands of Connecticut, is in the Mad River Valley, a tributary to the Naugatuck River. Geohydrologic units (aquifer materials) include unconsolidated glacial sediments (surficial materials) and fractured crystalline (metamorphic) bedrock. Surficial materials include glacial till, coarse-grained andfine-grained glacial stratified deposits, and postglacial floodplain alluvium and swamp deposits. The ground-water-flow system in the surficial aquifer is complex because the hydraulic properties of the surficial materials are highly variable. In the bedrock aquifer, ground water moves exclusively through fractures. Hydrologic characteristics of the crystalline bedrock-degree of confinement, hydraulic conductivity, storativity, and porosity-are poorly defined in the study area. Further study is needed to adequately assess ground-water flow and contaminant migration under current or past hydrologic conditions. All known water-supply wells in the study area obtain water from the bedrock aquifer. Twenty households in a hillside residential area on Tosun Road currently obtain drinking water from private wells tapping the bedrock aquifer. The extent of contamination in the bedrock aquifer and the potential for future contamination from known sources of contamination in the surficial aquifer is of concern to regulatory agencies. Previous investigations have identified ground-water contamination by volatile organic compounds at the Nutmeg Valley Road site area. Contamination has been associated with on-site disposal of heavy metals, chlorinated and non-chlorinated volatile organic compounds, and

Future research needs involving pathogens in groundwater

Science.gov (United States)

Bradford, Scott A.; Harvey, Ronald W.

2017-01-01

Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

Future research needs involving pathogens in groundwater

Science.gov (United States)

Bradford, Scott A.; Harvey, Ronald W.

2017-06-01

Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

[Study on the groundwater petroleum contaminant remediation by air sparging].

Science.gov (United States)

Wang, Zhi-Qiang; Wu, Qiang; Zou, Zu-Guang; Chen, Hong; Yang, Xun-Chang; Zhao, Ji-Chu

2007-04-01

The groundwater petroleum contaminant remediation effect by air sparging was investigated in an oil field. The results show that the soil geological situation has great influence on the air distribution, and the shape of air distribution is not symmetrical to the air sparging (AS) well as axis. The influence distance in the left of AS well is 6 m, and only 4 m in the right. The petroleum removal rate can reach 70% in the zone with higher air saturation, but only 40% in the zone with lower air saturation, and the average petroleum removal rate reaches 60% in the influence zone for 40 days continuous air sparging. The petroleum components in groundwater were analyzed by GC/MS (gas chromatogram-mass spectrograph) before and after experiments, respectively. The results show that the petroleum removal rate has relationship with the components and their properties. The petroleum components with higher volatility are easily removed by volatilization, but those with lower volatility are difficult to remove, so a tailing effect of lingering residual contaminant exists when the air sparging technology is adopted to treat groundwater contaminated by petroleum products.

Using enteric pathogens to assess sources of fecal contamination in the Silurian Dolomite Aquifer: Preliminary results

Science.gov (United States)

Muldoon, Maureen A; Borchardt, Mark A.; Spencer, Susan K.; Hunt, Randall J.; Owens, David

2018-01-01

The fractured Silurian dolomite aquifer is an important, but vulnerable, source of drinking water in northeast Wisconsin (Sherrill in Geology and ground water in Door County, Wisconsin, with emphasis on contamination potential in the Silurian dolomite, 1978; Bradbury and Muldoon in Hydrogeology and groundwater monitoring of fractured dolomite in the Upper Door Priority Watershed, Door County, Wisconsin, 1992; Muldoon and Bradbury in Assessing seasonal variations in recharge and water quality in the Silurian aquifer in areas with thicker soil cover. p 45, 2010). Areas underlain by the Silurian dolomite aquifer are extremely vulnerable to groundwater contamination from various land-use activities, especially the disposal of human wastewater and dairy manure. Currently there is no consensus as to which source of wastewater generates the greater impact to the aquifer.

Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona

International Nuclear Information System (INIS)

1993-09-01

This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site

Investigation of Contaminated Groundwater at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina, 2008

Science.gov (United States)

Vroblesky, Don A.; Petkewich, Matthew D.

2009-01-01

The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated volatile organic compound (VOC) groundwater contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina, beginning in 2000. The primary contaminants of interest in the study are tetrachloroethene, 1,1,1-trichloroethane, trichloroethene, cis-1,2-dichloroethene, vinyl chloride, 1,1-dichloroethane, and 1,1-dichloroethene. Engineered remediation aspects at the site consist of a zero-valent-iron permeable reactive barrier (PRB) installed in December 2002 intercepting the contamination plume and a phytoremediation test stand of loblolly pine trees planted in the source area in May 2003. The U.S. Geological Survey planted an additional phytoremediation test stand of loblolly pine trees on the upgradient side of the southern end of the PRB in February 2008. At least once during the summer, however, the trees were inadvertently mowed during lawn cutting activity. The PRB along the main axis of the contaminant plume appears to be actively removing contamination. In contrast to the central area of the PRB, the data from the southern end of the PRB indicate that contaminants are moving around the PRB. Concentrations in wells upgradient from the PRB showed a general decrease in VOC concentrations. VOC concentrations in some wells in the forest downgradient from the PRB showed a sharp increase in 2005, followed by a decrease in 2006. Farther downgradient in the forest, the VOC concentrations began to increase in 2007 and continued to increase into 2008. The VOC-concentration changes in groundwater beneath the forest appear to indicate movement of a groundwater-contaminant pulse through the forest. It also is possible that the data may represent lateral shifting of the plume in response to changes in groundwater-flow direction.

Transport from diffuse sources of contamination and its application to a coupled unsaturated - saturated system

OpenAIRE

Ommen, van, H.C.

1988-01-01

A simple theory to predict groundwater quality upon contamination from diffuse sources was developed. It appeared that an analogy exists between the predominant transport phenomena and the reaction of a reservoir, in which perfect mixing takes place. Such an analogy enables a simple incorporation of physico-chemical processes (decomposition, adsorption), as was shown by an illustrative response of the quality of groundwater to an input of a radio-active decaying solute (and its decay...

Limitations of sorption isotherms on modeling groundwater contaminant transport

International Nuclear Information System (INIS)

Silva, Eduardo Figueira da

2007-01-01

Design and safety assessment of radioactive waste repositories, as well as remediation of radionuclide contaminated groundwater require the development of models capable of accurately predicting trace element fate and transport. Adsorption of trace radionuclides onto soils and groundwater is an important mechanism controlling near- and far- field transport. Although surface complexation models (SCMs) can better describe the adsorption mechanisms of most radionuclides onto mineral surfaces by directly accounting for variability of system properties and mineral surface properties, isotherms are still used to model contaminant transport in groundwater, despite the much higher system dependence. The present work investigates differences between transport model results based on these two approaches for adsorption modeling. A finite element transport model is used for the isotherm model, whereas the computer program PHREEQC is used for the SCM approach. Both models are calibrated for a batch experiment, and one-dimensional transport is simulated using the calibrated parameters. At the lower injected concentrations there are large discrepancies between SCM and isotherm transport predictions, with the SCM presenting much longer tails on the breakthrough curves. Isotherms may also provide non-conservative results for time to breakthrough and for maximum concentration in a contamination plume. Isotherm models are shown not to be robust enough to predict transport behavior of some trace elements, thus discouraging their use. The results also illustrate the promise of the SCM modeling approach in safety assessment and environmental remediation applications, also suggesting that independent batch sorption measurements can be used, within the framework of the SCM, to produce a more versatile and realistic groundwater transport model for radionuclides which is capable of accounting more accurately for temporal and spatial variations in geochemical conditions. (author)

Hydrodynamic analysis of the interaction of two operating groundwater sources, case study: Groundwater supply of Bečej

Directory of Open Access Journals (Sweden)

Polomčić Dušan M.

2014-01-01

Full Text Available The existing groundwater source 'Vodokanal' for the public water supply of Bečej city in Serbia tapping groundwater from three water-bearing horizons over 15 wells with summary capacity of 100 l/s. Near the public water source of Bečej exists groundwater source 'Soja Protein' for industry with current capacity of 12 l/s which tapped same horizons. In the coming period is planned to increase summary capacity of this groundwater source up to 57 l/s. Also, the increase of summary city's source capacity is planned for 50 l/s in the next few years. That is means an increase of groundwater abstraction for an additional 84 % from the same water-bearing horizons. Application of hydrodynamic modeling, based on numerical method of finite difference will show the impact of increasing the total capacity of the source 'Soja Protein' on the groundwater level in groundwater source 'Vodokanal' and effects of additional decrease in groundwater levels, in all three water-bearing horizons, on the wells of the 'Vodokanala' groundwater source due to operation of industrial source. It was done 7 variant solutions of the extensions of groundwater sources and are their effects for a period of 10 years with the aim of the sustainable management of groundwater.

Combining stable isotopes with contamination indicators: A method for improved investigation of nitrate sources and dynamics in aquifers with mixed nitrogen inputs.

Science.gov (United States)

Minet, E P; Goodhue, R; Meier-Augenstein, W; Kalin, R M; Fenton, O; Richards, K G; Coxon, C E

2017-11-01

Excessive nitrate (NO 3 - ) concentration in groundwater raises health and environmental issues that must be addressed by all European Union (EU) member states under the Nitrates Directive and the Water Framework Directive. The identification of NO 3 - sources is critical to efficiently control or reverse NO 3 - contamination that affects many aquifers. In that respect, the use of stable isotope ratios 15 N/ 14 N and 18 O/ 16 O in NO 3 - (expressed as δ 15 N-NO 3 - and δ 18 O-NO 3 - , respectively) has long shown its value. However, limitations exist in complex environments where multiple nitrogen (N) sources coexist. This two-year study explores a method for improved NO 3 - source investigation in a shallow unconfined aquifer with mixed N inputs and a long established NO 3 - problem. In this tillage-dominated area of free-draining soil and subsoil, suspected NO 3 - sources were diffuse applications of artificial fertiliser and organic point sources (septic tanks and farmyards). Bearing in mind that artificial diffuse sources were ubiquitous, groundwater samples were first classified according to a combination of two indicators relevant of point source contamination: presence/absence of organic point sources (i.e. septic tank and/or farmyard) near sampling wells and exceedance/non-exceedance of a contamination threshold value for sodium (Na + ) in groundwater. This classification identified three contamination groups: agricultural diffuse source but no point source (D+P-), agricultural diffuse and point source (D+P+) and agricultural diffuse but point source occurrence ambiguous (D+P±). Thereafter δ 15 N-NO 3 - and δ 18 O-NO 3 - data were superimposed on the classification. As δ 15 N-NO 3 - was plotted against δ 18 O-NO 3 - , comparisons were made between the different contamination groups. Overall, both δ variables were significantly and positively correlated (p contamination groups revealed that denitrification did not occur in the absence of point

Removal of arsenic from contaminated groundwater by solar-driven membrane distillation

International Nuclear Information System (INIS)

Manna, Ajay K.; Sen, Mou; Martin, Andrew R.; Pal, Parimal

2010-01-01

Experimental investigations were carried out on removal of arsenic from contaminated groundwater by employing a new flat-sheet cross flow membrane module fitted with a hydrophobic polyvinylidenefluoride (PVDF) microfiltration membrane. The new design of the solar-driven membrane module in direct contact membrane distillation (DCMD) configuration successfully produced almost 100 per cent arsenic-free water from contaminated groundwater in a largely fouling-free operation while permitting high fluxes under reduced temperature polarization. For a feed flow rate of 0.120 m 3 /h, the 0.13 μm PVDF membrane yielded a high flux of 74 kg/(m 2 h) at a feed water temperature of 40 deg. C and, 95 kg/m 2 h at a feed water temperature of 60 deg. C. The encouraging results show that the design could be effectively exploited in the vast arsenic-affected rural areas of South-East Asian countries blessed with abundant sunlight particularly during the critical dry season. - Solar-driven membrane distillation has the potential of removing arsenic from contaminated groundwater.

Arsenic and fluoride contaminated groundwaters: A review of current technologies for contaminants removal.

Science.gov (United States)

Jadhav, Sachin V; Bringas, Eugenio; Yadav, Ganapati D; Rathod, Virendra K; Ortiz, Inmaculada; Marathe, Kumudini V

2015-10-01

Chronic contamination of groundwaters by both arsenic (As) and fluoride (F) is frequently observed around the world, which has severely affected millions of people. Fluoride and As are introduced into groundwaters by several sources such as water-rock interactions, anthropogenic activities, and groundwater recharge. Coexistence of these pollutants can have adverse effects due to synergistic and/or antagonistic mechanisms leading to uncertain and complicated health effects, including cancer. Many developing countries are beset with the problem of F and As laden waters, with no affordable technologies to provide clean water supply. The technologies available for the simultaneous removal are akin to chemical treatment, adsorption and membrane processes. However, the presence of competing ions such as phosphate, silicate, nitrate, chloride, carbonate, and sulfate affect the removal efficiency. Highly efficient, low-cost and sustainable technology which could be used by rural populations is of utmost importance for simultaneous removal of both pollutants. This can be realized by using readily available low cost materials coupled with proper disposal units. Synthesis of inexpensive and highly selective nanoadsorbents or nanofunctionalized membranes is required along with encapsulation units to isolate the toxicant loaded materials to avoid their re-entry in aquifers. A vast number of reviews have been published periodically on removal of As or F alone. However, there is a dearth of literature on the simultaneous removal of both. This review critically analyzes this important issue and considers strategies for their removal and safe disposal. Copyright © 2015 Elsevier Ltd. All rights reserved.

PHYTOREMEDIATION: USING PLANTS TO CLEAN UP CONTAMINATED SOIL, GROUNDWATER, AND WASTEWATER

Science.gov (United States)

Phytoremediation is an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost. The cleanup technology is defined as the use of green plants to remove, contain, or render harmless such environmental contaminants as heavy ...

Recharge heterogeneity and high intensity rainfall events increase contamination risk for Mediterranean groundwater resources

Science.gov (United States)

Hartmann, Andreas; Jasechko, Scott; Gleeson, Tom; Wada, Yoshihide; Andreo, Bartolomé; Barberá, Juan Antonio; Brielmann, Heike; Charlier, Jean-Baptiste; Darling, George; Filippini, Maria; Garvelmann, Jakob; Goldscheider, Nico; Kralik, Martin; Kunstmann, Harald; Ladouche, Bernard; Lange, Jens; Mudarra, Matías; Francisco Martín, José; Rimmer, Alon; Sanchez, Damián; Stumpp, Christine; Wagener, Thorsten

2017-04-01

Karst develops through the dissolution of carbonate rock and results in pronounced spatiotemporal heterogeneity of hydrological processes. Karst groundwater in Europe is a major source of fresh water contributing up to half of the total drinking water supply in some countries like Austria or Slovenia. Previous work showed that karstic recharge processes enhance and alter the sensitivity of recharge to climate variability. The enhanced preferential flow from the surface to the aquifer may be followed by enhanced risk of groundwater contamination. In this study we assess the contamination risk of karst aquifers over Europe and the Mediterranean using simulated transit time distributions. Using a new type of semi-distributed model that considers the spatial heterogeneity of karst hydraulic properties, we were able to simulate karstic groundwater recharge including its heterogeneous spatiotemporal dynamics. The model is driven by gridded daily climate data from the Global Land Data Assimilation System (GLDAS). Transit time distributions are calculated using virtual tracer experiments. We evaluated our simulations by independent information on transit times derived from observed time series of water isotopes of >70 karst springs over Europe. The simulations indicate that, compared to humid, mountain and desert regions, the Mediterranean region shows a stronger risk of contamination in Europe because preferential flow processes are most pronounced given thin soil layers and the seasonal abundance of high intensity rainfall events in autumn and winter. Our modelling approach includes strong simplifications and its results cannot easily be generalized but it still highlights that the combined effects of variable climate and heterogeneous catchment properties constitute a strong risk on water quality.

Use of tree-ring chemistry to document historical ground-water contamination events

Science.gov (United States)

Vroblesky, Don A.; Yanosky, Thomas M.

1990-01-01

The annual growth rings of tulip trees (Liriodendron tulipifera L.) appear to preserve a chemical record of ground-water contamination at a landfill in Maryland. Zones of elevated iron and chlorine concentrations in growth rings from trees immediately downgradient from the landfill are closely correlated temporally with activities in the landfill expected to generate iron and chloride contamination in the ground water. Successively later iron peaks in trees increasingly distant from the landfill along the general direction of ground-water flow imply movement of iron-contaminated ground water away from the landfill. The historical velocity of iron movement (2 to 9 m/yr) and chloride movement (at least 40 m/yr) in ground water at the site was estimated from element-concentration trends of trees at successive distances from the landfill. The tree-ring-derived chloride-transport velocity approximates the known ground-water velocity (30 to 80 m/yr). A minimum horizontal hydraulic conductivity (0.01 to .02 cm/s) calculated from chloride velocity agrees well with values derived from aquifer tests (about 0.07 cm/s) and from ground-water modeling results (0.009 to 0.04 cm/s).

The use of nitrate isotopes to identify contamination sources in the Bou-Areg aquifer (Morocco)

Energy Technology Data Exchange (ETDEWEB)

Re, Viviana [Ca' Foscari University of Venice, Department of Molecular Sciences and Nanosystems, Dorsoduro 2137, Venice, 30123 (Italy); Sacchi, Elisa [University of Pavia, Department of Earth and Environmental Sciences, Via Ferrata 1, Pavia, 27100 (Italy); Allais, Enrico [ISO4 s.n.c., Via Ferrata 1, Pavia, 27100 (Italy)

2013-07-01

The Bou-Areg coastal aquifer (Morocco) is affected by high nitrate levels in groundwater, with possible consequences for the natural environment and human health. The use of environmental tracers, including δ{sup 15}NNO{sub 3} and δ{sup 18}ONO{sub 3}, allowed identifying the main sources of nitrate contamination in groundwater samples collected in 2010. These are manure and septic effluents, especially in urban areas, and synthetic fertilizers in agricultural areas. This work represents a preliminary step for a more detailed nitrate vulnerability assessment to support groundwater management and protection in the studied region. (authors)

Groundwater arsenic contamination from parts of the Ghaghara Basin, India: influence of fluvial geomorphology and Quaternary morphostratigraphy

Science.gov (United States)

Shah, Babar Ali

2017-09-01

A groundwater arsenic (As) distribution in Faizabad, Gonda, and Basti districts of Uttar Pradesh is shown in the entrenched channels and floodplains of the Ghaghara River. Tubewell water samples were analysed for As through flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) system. About 38, 61, and 42 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, have As >10 µg/l (WHO guideline). Moreover, 15, 45, and 26 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, have As above 50 µg/l. About 86, 69, and 35 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, are from shallow depth (21-45 m), and it is worth noticing that 47 % As-contaminated (As >10 µg/l) tubewells in these three districts are located within the depth of 10-35 m in Holocene Newer Alluvium aquifers. The high content of As (7.11 mg/kg) is measured in suspended river sediments of the Ghaghara River. Most of the As-contaminated villages in the Ghaghara Basin are located close to abandoned or present meander channels and floodplains of the Ghaghara River. In contrast, tubewells in Faizabad, Ayodhya, and Nawabganj towns are As-safe because of their positions on the Pleistocene Older Alluvium upland surfaces. Quaternary geomorphology plays an important role in groundwater arsenic contamination in the Ghaghara Basin. The sources of groundwater arsenic are geogenic and perennial mountainous rivers in the Ghaghara Basin supplied high sediment loads. The arsenic in groundwater of Ghaghara Basin is getting released from associated sediments which were likely deposited from the Himalayas. The process of release of groundwater arsenic is reductive dissolution of iron hydroxides.

The Biogeochemistry of Contaminant Groundwater Plumes Arising from Waste Disposal Facilities

DEFF Research Database (Denmark)

Bjerg, Poul Løgstrup; Albrechtsen, Hans-Jørgen; Kjeldsen, Peter

2014-01-01

Landfills with solid waste are abundant sources of groundwater pollution all over the world. Old uncontrolled municipal landfills are often large, heterogeneous sources with demolition waste, minor fractions of commercial or industrial waste, and organic waste from households. Strongly anaerobic...... leachate with a high content of dissolved organic carbon, salts, and ammonium, as well as specific organic compounds and metals is released from the waste for decades or centuries. Landfill leachate plume hosts a variety of biogeochemical processes, which is the key to understand the significant potential...... and the literature are the following: (1) Local hydrogeological conditions in the landfill area may affect the spreading of the contaminants; (2) investigations of landfill leachate plumes in geologic settings with clayey till deposits and fractured consolidated sediments are lacking; (3) the size of the landfill...

High (36)Cl/Cl ratios in Chernobyl groundwater.

Science.gov (United States)

Roux, Céline; Le Gal La Salle, Corinne; Simonucci, Caroline; Van Meir, Nathalie; Fifield, L Keith; Diez, Olivier; Bassot, Sylvain; Simler, Roland; Bugai, Dmitri; Kashparov, Valery; Lancelot, Joël

2014-12-01

After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A (90)Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, (36)Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater. (36)Cl/Cl ratios measured in groundwater, trench soil water and leaf leachates are 1-5 orders of magnitude higher than the theoretical natural (36)Cl/Cl ratio. This contamination occurred after the Chernobyl explosion and currently persists. Trench T22 acts as an obvious modern point source of (36)Cl, however other sources have to be involved to explain such contamination. (36)Cl contamination of groundwater can be explained by dilution of trench soil water by uncontaminated water (rainwater or deep groundwater). With a plume extending further than that of (90)Sr, radionuclide which is impacted by retention and decay processes, (36)Cl can be considered as a suitable tracer of contamination from the trench in groundwater provided that modern release processes of (36)Cl from trench soil are better characterized. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transport from diffuse sources of contamination and its application to a coupled unsaturated - saturated system

NARCIS (Netherlands)

Ommen, van H.C.

1988-01-01

A simple theory to predict groundwater quality upon contamination from diffuse sources was developed. It appeared that an analogy exists between the predominant transport phenomena and the reaction of a reservoir, in which perfect mixing takes place. Such an analogy enables a simple

Arsenic geochemistry of groundwater in Southeast Asia.

Science.gov (United States)

Kim, Kyoung-Woong; Chanpiwat, Penradee; Hanh, Hoang Thi; Phan, Kongkea; Sthiannopkao, Suthipong

2011-12-01

The occurrence of high concentrations of arsenic in the groundwater of the Southeast Asia region has received much attention in the past decade. This study presents an overview of the arsenic contamination problems in Vietnam, Cambodia, Lao People's Democratic Republic and Thailand. Most groundwater used as a source of drinking water in rural areas has been found to be contaminated with arsenic exceeding the WHO drinking water guideline of 10 μg·L(-1). With the exception of Thailand, groundwater was found to be contaminated with naturally occurring arsenic in the region. Interestingly, high arsenic concentrations (> 10 μg·L(-1)) were generally found in the floodplain areas located along the Mekong River. The source of elevated arsenic concentrations in groundwater is thought to be the release of arsenic from river sediments under highly reducing conditions. In Thailand, arsenic has never been found naturally in groundwater, but originates from tin mining activities. More than 10 million residents in Southeast Asia are estimated to be at risk from consuming arsenic-contaminated groundwater. In Southeast Asia, groundwater has been found to be a significant source of daily inorganic arsenic intake in humans. A positive correlation between groundwater arsenic concentration and arsenic concentration in human hair has been observed in Cambodia and Vietnam. A substantial knowledge gap exists between the epidemiology of arsenicosis and its impact on human health. More collaborative studies particularly on the scope of public health and its epidemiology are needed to conduct to fulfill the knowledge gaps of As as well as to enhance the operational responses to As issue in Southeast Asian countries.

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Energy Technology Data Exchange (ETDEWEB)

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-03-01

Groundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area for the protection of the public and the environment.

Determination of 90Sr and Pu isotopes in contaminated groundwater samples by inductively coupled plasma mass spectrometry

Science.gov (United States)

Zoriy, Miroslav V.; Ostapczuk, Peter; Halicz, Ludwik; Hille, Ralf; Becker, J. Sabine

2005-04-01

A sensitive analytical method for determining the artificial radionuclides 90Sr, 239Pu and 240Pu at the ultratrace level in groundwater samples from the Semipalatinsk Test Site area in Kazakhstan by double-focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS) was developed. In order to avoid possible isobaric interferences at m/z 90 for 90Sr determination (e.g. 90Zr+, 40Ar50Cr+, 36Ar54Fe+, 58Ni16O2+, 180Hf2+, etc.), the measurements were performed at medium mass resolution under cold plasma conditions. Pu was separated from uranium by means of extraction chromatography using Eichrom TEVA resin with a recovery of 83%. The limits of detection for 90Sr, 239Pu and 240Pu in water samples were determined as 11, 0.12 and 0.1 fg ml-1, respectively. Concentrations of 90Sr and 239Pu in contaminated groundwater samples ranged from 18 to 32 and from 28 to 856 fg ml-1, respectively. The 240Pu/239Pu isotopic ratio in groundwater samples was measured as 0.17. This isotope ratio indicates that the most probable source of contamination of the investigated groundwater samples was the nuclear weapons tests at the Semipalatinsk Test Site conducted by the USSR in the 1960s.

Soil treatment and groundwater control for No. 6 fuel oil and PCB contamination

International Nuclear Information System (INIS)

Girioni, M.J.; St. Hilaire, W.J.

1991-01-01

This paper reports that as part of a Short-Term Measure ordered by the Massachusetts Department of Environmental Protection (DEP), soil contaminated by No. 6 fuel oil and low-level polychlorinated biphenyls (PCBs) was excavated, treated and recycled on-site as an asphalt base course for a parking lot at an industrial complex in New Bedford, Massachusetts. Approximately 300 cubic yards of contaminated soil were treated with an asphalt emulsion and utilized as a aggregate component for asphalt processed at ambient temperatures during the month of December 1990. In order to determine if the contaminated soils to be recycled would be classified as a hazardous waste (as defined by the Massachusetts Hazardous Waste Regulations, 310 CMR 30.000), or if the soil to be recycled would pose a significant risk to health, safety or the environment, analytical testing of the contaminated soil was conducted prior, during and after treatment. Analytical testing included Toxicity Characteristics Leaching Procedure (TCLP) analyses of the untreated and treated soil. An alternative solution to the standard groundwater pump-and-treat method was designed and constructed to control and recover the highly viscous floating petroleum product. A series of precast leaching galleys (oil collection chambers) and a precast leach pit (groundwater discharge structure) were constructed to alter the local groundwater table to induce groundwater flow by gravity into the leaching chambers. Passive (i.e., nonpumping) groundwater flow to the leaching chambers was induced by placing of the groundwater discharge structure hydraulically downgradient of the leaching chambers. Collected oil, separated by gravity, will be periodically vacuumed, as necessary, for proper off-site disposal. Excess water discharges to the downgradient leach pit

Studying The Contamination Status And The Sources Of Nitrogen Compounds In Groundwater In Ho Chi Minh City Area Using The Isotope Hydrology Techniques

International Nuclear Information System (INIS)

Nguyen Kien Chinh; Le Danh Chuan; Nguyen Van Nhien; Huynh Long; Tran Bich Lien; Luong Thu Tra

2013-01-01

The obtained data on nitrate, ammonium and total nitrogen concentration of 100 groundwater samples collected from 3 main aquifers show that although the nitrate concentration is still lower than the authorized limit of this compound in groundwater but the concentration and, specially the distribution of nitrate in shallow aquifer (Pleistocene) shows the increasing tendency in pollution level while ammonium and also total nitrogen content exceeded the authorized limit of these compounds in groundwater. For deeper aquifers (Upper and Lower Pliocene) groundwater is less polluted by nitrogen compounds. Analysis data on isotopic composition δ 15 N and δ 18 O of nitrate of the collected groundwater samples in compiling with other environmental isotopes data as δ 2 H, δ 18 O of water and natural radioactive isotopes in groundwater ( 3 H and 14 C) show that nitrate in Pleistocene groundwater is derived from both sources, geogenic source such as organic matter buried in aquifer soil layers and anthropogenic source like fertilizers, manure and septic wastes with the dominance of anthropogenic source. At the same time, obtained isotopic data proved the geogenic source of nitrate in water of the deeper aquifers. Study results on infiltration rate and infiltration depth of fertilizers and water using tracer techniques in the zone specializing in legume cultivation of the study area show the possible infiltration into shallow groundwater of water and also fertilizers. The obtained results prove the need of better management of the use of fertilizers for cultivation activities in the study area and to apply the advanced cultural manners for minimizing amount of fertilizers used. At the same time to strengthen wastes management and treatment in whole study area, especially in the zones which intake rain water as a recharge source to shallow groundwater such as Cu Chi, Hoc Mon and also inner city districts. (author)

Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona. Draft

Energy Technology Data Exchange (ETDEWEB)

1993-09-01

This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site.

[Simulation on contamination forecast and control of groundwater in a certain hazardous waste landfill].

Science.gov (United States)

Ma, Zhi-Fei; An, Da; Jiang, Yong-Hai; Xi, Bei-Dou; Li, Ding-Long; Zhang, Jin-Bao; Yang, Yu

2012-01-01

On the basis of site investigation and data collection of a certain hazardous waste landfill, the groundwater flow and solute transport coupled models were established by applying Visual Modflow software, which was used to conduct a numerical simulation that forecast the transport process of Cr6+ in groundwater and the effects of three control measures (ground-harden, leakage-proof barriers and drainage ditches) of contaminants transport after leachate leakage happened in impermeable layer of the landfill. The results show that the contamination plume of Cr6+ transports with groundwater flow direction, the contamination rang would reach the pool's boundary in 10 years, and the distance of contamination transport is 1 450 m. But the diffusion range of contamination plume would not be obviously expanded between 10 and 20 years. While the ground is hardened, the contamination plume would not reach the pool's boundary in 20 years. When the leakage-proof barrier is set in the bottom of water table aquifer, the concentration of Cr6+ is higher than that the leakage-proof barrier is unset, but the result is just opposite when setting the leakage-proof barrier in the bottom of underlying aquifer. The range of contamination plume is effectively controlled by setting drainage ditches that water discharge is 2 642 m3 x d(-1), which makes the monitoring wells would not be contaminated in 20 years. Moreover, combining the ground-harden with drainage ditches can get the best effect in controlling contaminants diffusion, and meanwhile, the drainage ditches' daily discharge is reduced to 1 878 m3 x d(-1). Therefore, it is suggested that the control measure combining the ground-harden with drainage ditches should apply to prevent contamination diffusion in groundwater when leachate leakage have happened in impermeable layer of the landfill.

Tracing nitrate pollution sources and transformation in surface- and ground-waters using environmental isotopes

International Nuclear Information System (INIS)

Zhang, Yan; Li, Fadong; Zhang, Qiuying; Li, Jing; Liu, Qiang

2014-01-01

Water pollution in the form of nitrate nitrogen (NO 3 − –N) contamination is a major concern in most agricultural areas in the world. Concentrations and nitrogen and oxygen isotopic compositions of nitrate, as well as oxygen and deuterium isotopic compositions of surface and groundwater from a typical irrigated region in the North China Plain (NCP) collected from May to October in 2012 were analyzed to examine the major nitrate sources and transformations. Concentrations of NO 3 − –N ranged from 0.2 to 29.6 mg/L (mean of 11.2 mg/L) in surface water, and from 0.1 to 19.4 mg/L (mean of 2.8 mg/L) in groundwater. Approximately 46.7% of the surface water samples and 10% of the groundwater samples exceeded the World Health Organization (WHO) drinking water standard for NO 3 − –N. Surface water samples that exceeded the standard were collected mainly in the dry season (May and October), while groundwater samples that exceeded the standard were collected in the wet season (June). Overall, the highest nitrate levels were observed in surface water in May and in groundwater in June, indicating that fertilizer application, precipitation, and irrigation strongly influence the NO 3 − –N concentrations. Analyses of isotopic compositions suggest that the main sources of nitrate are nitrification of fertilizer and sewage in surface water, in contrast, mineralization of soil organic N and sewage is the groundwater sources during the dry season. When fertilizers are applied, nitrate will be transported by precipitation through the soil layers to the groundwater in the wet season (June). Denitrification only occurred in surface water in the wet season. Attempts should be made to minimize overuse of nitrogen fertilizers and to improve nitrogen use efficiency in irrigated agricultural regions. - Highlights: • Nitrate sources in surface and groundwater were identified by multiple isotopes. • Nitrate pollution displayed obvious seasonal variations. • Nitrate of

Tracing nitrate pollution sources and transformation in surface- and ground-waters using environmental isotopes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yan [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Fadong, E-mail: lifadong@igsnrr.ac.cn [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Zhang, Qiuying [Center for Agricultural Resources Research, Chinese Academy of Sciences, Shijiazhuang 050021 (China); Li, Jing [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Qiang [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2014-08-15

Water pollution in the form of nitrate nitrogen (NO{sub 3}{sup −}–N) contamination is a major concern in most agricultural areas in the world. Concentrations and nitrogen and oxygen isotopic compositions of nitrate, as well as oxygen and deuterium isotopic compositions of surface and groundwater from a typical irrigated region in the North China Plain (NCP) collected from May to October in 2012 were analyzed to examine the major nitrate sources and transformations. Concentrations of NO{sub 3}{sup −}–N ranged from 0.2 to 29.6 mg/L (mean of 11.2 mg/L) in surface water, and from 0.1 to 19.4 mg/L (mean of 2.8 mg/L) in groundwater. Approximately 46.7% of the surface water samples and 10% of the groundwater samples exceeded the World Health Organization (WHO) drinking water standard for NO{sub 3}{sup −}–N. Surface water samples that exceeded the standard were collected mainly in the dry season (May and October), while groundwater samples that exceeded the standard were collected in the wet season (June). Overall, the highest nitrate levels were observed in surface water in May and in groundwater in June, indicating that fertilizer application, precipitation, and irrigation strongly influence the NO{sub 3}{sup −}–N concentrations. Analyses of isotopic compositions suggest that the main sources of nitrate are nitrification of fertilizer and sewage in surface water, in contrast, mineralization of soil organic N and sewage is the groundwater sources during the dry season. When fertilizers are applied, nitrate will be transported by precipitation through the soil layers to the groundwater in the wet season (June). Denitrification only occurred in surface water in the wet season. Attempts should be made to minimize overuse of nitrogen fertilizers and to improve nitrogen use efficiency in irrigated agricultural regions. - Highlights: • Nitrate sources in surface and groundwater were identified by multiple isotopes. • Nitrate pollution displayed obvious

The Grand Challenge of Basin-Scale Groundwater Quality Management Modelling

Science.gov (United States)

Fogg, G. E.

2017-12-01

The last 50+ years of agricultural, urban and industrial land and water use practices have accelerated the degradation of groundwater quality in the upper portions of many major aquifer systems upon which much of the world relies for water supply. In the deepest and most extensive systems (e.g., sedimentary basins) that typically have the largest groundwater production rates and hold fresh groundwaters on decadal to millennial time scales, most of the groundwater is not yet contaminated. Predicting the long-term future groundwater quality in such basins is a grand scientific challenge. Moreover, determining what changes in land and water use practices would avert future, irreversible degradation of these massive freshwater stores is a grand challenge both scientifically and societally. It is naïve to think that the problem can be solved by eliminating or reducing enough of the contaminant sources, for human exploitation of land and water resources will likely always result in some contamination. The key lies in both reducing the contaminant sources and more proactively managing recharge in terms of both quantity and quality, such that the net influx of contaminants is sufficiently moderate and appropriately distributed in space and time to reverse ongoing groundwater quality degradation. Just as sustainable groundwater quantity management is greatly facilitated with groundwater flow management models, sustainable groundwater quality management will require the use of groundwater quality management models. This is a new genre of hydrologic models do not yet exist, partly because of the lack of modeling tools and the supporting research to model non-reactive as well as reactive transport on large space and time scales. It is essential that the contaminant hydrogeology community, which has heretofore focused almost entirely on point-source plume-scale problems, direct it's efforts toward the development of process-based transport modeling tools and analyses capable

Treatability study on the Bear Creek Valley characterization area at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Phase II work plan for S-3 site contaminated groundwater interception--in-field media evaluation and groundwater capture methods

International Nuclear Information System (INIS)

1996-12-01

A treatability study is being conducted to support implementation:of early actions at the S-3 Site in the Bear Creek Valley (BCV) Characterization Area (CA). The objectives of the early actions Will be (1) to reduce concentrations of uranium and nitrate in Bear Creek and (2) to reduce contaminants of concern in North Tributary (NT)-1 and NT-2. The BCV CA is located within the US DOE's Oak Ridge Reservation in Tennessee. Hazardous and radioactive materials from the Y-12 Plant operations were, disposed of at various sites within BCV. Groundwater and surface water in the BCV CA have been contaminated. The remedial investigation (RI) for the BCV CA identified that the greatest mass flux of contaminants from the various sources migrates via groundwater at the source and discharges to surface water in Bear Creek and its tributaries. In the RI, the combined discharge from the S-3 Site and the Boneyard/Burnyard (BYBY) was identified as accounting for 75% of the cancer risk and more than 80% of the chemical toxicity to Potential downgradient human receptors. In addition, the S-3 Site has caused degradation of surface water quality in upper Bear Creek and two of its tributaries. The BCV CA treatability study focuses on capture and treatment of shallow groundwater before it discharges to tributary waters. The objectives Of treatment of this groundwater are (1) to reduce the concentrations of uranium and nitrate in NT-1 and Bear Creek such that the concentrations of these chemicals in surface water and groundwater are reduced to acceptable levels, (2) to reduce the concentrations of nitrate and metals, and reduce the overall concentration of total dissolved solids; and (3) to hydraulically contain the plume of contaminated, groundwater that is moving in bedrock in the Nolichucky Shale such that the rate of contaminant discharge will be reduced in the long term. The objective of Phase II is to produce conceptual designs for treatment system configurations

Establishing indices for groundwater contamination risk assessment in the vicinity of hazardous waste landfills in China.

Science.gov (United States)

Li, Ying; Li, Jinhui; Chen, Shusheng; Diao, Weihua

2012-06-01

Groundwater contamination by leachate is the most damaging environmental impact over the entire life of a hazardous waste landfill (HWL). With the number of HWL facilities in China rapidly increasing, and considering the poor status of environmental risk management, it is imperative that effective environmental risk management methods be implemented. A risk assessment indices system for HWL groundwater contamination is here proposed, which can simplify the risk assessment procedure and make it more user-friendly. The assessment framework and indices were drawn from five aspects: source term, underground media, leachate properties, risk receptors and landfill management quality, and a risk assessment indices system consisting of 38 cardinal indicators was established. Comparison with multimedia models revealed that the proposed indices system was integrated and quantitative, that input data for it could be easily collected, and that it could be widely used for environmental risk assessment (ERA) in China. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Natural radioactivity in groundwater sources in Ireland

Energy Technology Data Exchange (ETDEWEB)

Currivan, L.; Dowdall, A.; Mcginnity, P.; Ciara, M. [Radiological Protection Institute of Ireland (Ireland); Craig, M. [Environmental Protection Agency (Ireland)

2014-07-01

The Radiological Protection Institute of Ireland (RPII) in collaboration with the Irish Environmental Protection Agency (EPA) undertook a national survey of radioactivity in groundwater sources for compliance with parameters set out in the European Communities Drinking Water Directive. The Directive outlines the minimum requirements for the quality of drinking water and water intended for human consumption. Over two hundred samples were screened for radioactivity. Where indicated, analysis for individual radionuclide activity was undertaken and the radiation dose arising calculated. Furthermore, samples were analysed for radon concentration. This survey is the first comprehensive national survey of radioactivity in groundwater sources in Ireland. Approximately 18 per cent of drinking water in Ireland originates from groundwater and springs with the remainder from surface water. Between 2007 and 2011, water samples from a representative network of groundwater sources were analysed and assessed for compliance with the radioactivity parameters set out in the Drinking Water Directive. The assessment was carried out using the methodology for screening drinking water set out by the WHO. For practical purposes the WHO recommended screening levels for drinking water below which no further action is required of 100 mBq/l for gross alpha activity and 1000 mBq/l for gross beta activity were applied. Of the 203 groundwater sources screened for gross alpha and gross beta all met the gross beta activity criteria of less than 1000 mBq/l and 175 supplies had gross alpha activity concentrations of less than 100 mBq/l. For these sources no further analysis was required. The remaining 28 sources required further (radionuclide-specific) analysis from an alpha activity perspective. Results on ranges and distributions of radionuclide concentrations in groundwater as well as ingestion doses estimated for consumers of these water supplies will be presented. Document available in abstract

Sources for increased DOC-concentrations in the groundwater downstream of the landfill Hohne (DEA)

International Nuclear Information System (INIS)

Bahlmann, E.; Seifert, R.; Eschenbach, A.; Kleinschmidt, V.

2017-08-01

Construction waste together with drilling mud and oil-contaminated soil had been deposited in the landfill Hohne from 1971. Four groundwater monitoring sites had been installed: one monitoring site upstream and three sites downstream of the landfill in three different directions. Downstream of the landfill increased concentrations of chloride, sulphate, sodium and DOC (dissolved organic carbon) had been measured over a period of years. Particularly the source of the DOC has remained unclear. Assumptions were (i) leaking of contaminants from the landfill and degradation under the landfill by microbes or plants or (ii) leaching of DOC from the soil under the landfill caused by a change in the redox potential. The determination of the DOC source was the major subject of this study.

Arsenic contamination of groundwater in Bangladesh

International Nuclear Information System (INIS)

2003-01-01

Shallow groundwater with high arsenic concentrations from naturally occurring sources is the primary source of drinking water for millions of people in Bangladesh. It has resulted in a major public health crisis with as many as 70 million people possibly at risk. The International Atomic Energy Agency (IAEA) is supporting international efforts and the Government of Bangladesh to find alternative, safe and sustainable sources of drinking water. (IAEA)

Groundwater Impacts of Radioactive Wastes and Associated Environmental Modeling Assessment

Energy Technology Data Exchange (ETDEWEB)

Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan

2012-11-01

This article provides a review of the major sources of radioactive wastes and their impacts on groundwater contamination. The review discusses the major biogeochemical processes that control the transport and fate of radionuclide contaminants in groundwater, and describe the evolution of mathematical models designed to simulate and assess the transport and transformation of radionuclides in groundwater.

Integrated modelling for assessing the risk of groundwater contaminants to human health and surface water ecosystems

DEFF Research Database (Denmark)

McKnight, Ursula S.; Rasmussen, Jes; Funder, Simon G.

2010-01-01

for evaluating the impact of a TCE groundwater plume, located in an area with protected drinking water interests, to human health and surface water ecosystems. This is accomplished by coupling the system dynamicsbased decision support system CARO-Plus to the aquatic ecosystem model AQUATOX via an analytical......The practical implementation of the European Water Framework Directive has resulted in an increased focus on the groundwater-surface water interaction zone. A gap exists with respect to preliminary assessment methodologies that are capable of evaluating and prioritising point sources...... volatilisation model for the stream. The model is tested on a Danish case study involving a 750 m long TCE groundwater plume discharging into a stream. The initial modelling results indicate that TCE contaminant plumes with μgL-1 concentrations entering surface water systems do not pose a significant risk...

In situ treatment of cyanide-contaminated groundwater by iron cyanide precipitation

International Nuclear Information System (INIS)

Ghosh, R.S.; Dzombak, D.A.; Luthy, R.G.; Smith, J.R.

1999-01-01

Groundwater contamination with cyanide is common at many former or active industrial sites. Metal-cyanide complexes typically dominate aqueous speciation of cyanide in groundwater systems, with iron-cyanide complexes often most abundant. Typically, metal-cyanide complexes behave as nonadsorbing solutes in sand-gravel aquifer systems in the neutral pH range, rendering cyanide relatively mobile in groundwater systems. Groundwater pump-and-treat systems have often been used to manage cyanide contamination in groundwater. This study examined the feasibility of using in situ precipitation of iron cyanide in a reactive barrier to attenuate the movement of cyanide in groundwater. Laboratory column experiments were performed in which cyanide solutions were passed through mixtures of sand and elemental iron filings. Removal of dissolved cyanide was evaluated in a variety of cyanide-containing influents under various flow rates and sand-to-iron weight ratios. Long-term column tests performed with various cyanide-containing influents under both oxic and anoxic conditions, at neutral pH and at flow rates typical of sand-gravel porous media, yielded effluent concentrations of total cyanide as low as 0.5 mg/L. Effluent cyanide concentrations achieved were close to the solubilities of Turnbull's blue-hydrous ferric oxide solid solutions, indicating co-precipitation of the two solids. Maximum cyanide removal efficiency was achieved with approximately 10% by weight of iron in the sand-iron mixtures; higher iron contents did not increase removal efficiency significantly. Results obtained indicate that in situ precipitation is a promising passive treatment approach for cyanide in groundwater

Source and Processes of Dissolved Organic Matter in a Bangladesh Groundwater

Science.gov (United States)

McKnight, D. M.; Simone, B. E.; Mladenov, N.; Zheng, Y.; Legg, T. M.; Nemergut, D.

2010-12-01

Arsenic contamination of groundwater is a global health crisis, especially in Bangladesh where an estimated 40 million people are at risk. The release of geogenic arsenic bound to sediments into groundwater is thought to be influenced by dissolved organic matter (DOM) through several biogeochemical processes. Abiotically, DOM can promote the release of sediment bound As through the formation of DOM-As complexes and competitive interactions between As and DOM for sorption sites on the sediment. Additionally, the labile portion of groundwater DOM can serve as an electron donor to support microbial growth and the more recalcitrant humic DOM may serve as an electron shuttle, facilitating the eventual reduction of ferric iron present as iron oxides in sediments and consequently the mobilization of sorbed As and organic material. The goal of this study is to understand the source of DOM in representative Bangladesh groundwaters and the DOM sorption processes that occur at depth. We report chemical characteristics of representative DOM from a surface water, a shallow low-As groundwater, mid-depth high-As groundwater from the Araihazar region of Bangladesh. The humic DOM from groundwater displayed a more terrestrial chemical signature, indicative of being derived from plant and soil precursor materials, while the surface water humic DOM had a more microbial signature, suggesting an anthropogenic influence. In terms of biogeochemical processes occurring in the groundwater system, there is evidence from a diverse set of chemical characteristics, ranging from 13C-NMR spectroscopy to the analysis of lignin phenols, for preferential sorption onto iron oxides influencing the chemistry and reactivity of humic DOM in high As groundwater in Bangladesh. Taken together, these results provide chemical evidence for anthropogenic influence and the importance of sorption reactions at depth controlling the water quality of high As groundwater in Bangladesh.

Delineating sources of groundwater recharge in an arsenic-affected Holocene aquifer in Cambodia using stable isotope-based mixing models

Science.gov (United States)

Richards, Laura A.; Magnone, Daniel; Boyce, Adrian J.; Casanueva-Marenco, Maria J.; van Dongen, Bart E.; Ballentine, Christopher J.; Polya, David A.

2018-02-01

Chronic exposure to arsenic (As) through the consumption of contaminated groundwaters is a major threat to public health in South and Southeast Asia. The source of As-affected groundwaters is important to the fundamental understanding of the controls on As mobilization and subsequent transport throughout shallow aquifers. Using the stable isotopes of hydrogen and oxygen, the source of groundwater and the interactions between various water bodies were investigated in Cambodia's Kandal Province, an area which is heavily affected by As and typical of many circum-Himalayan shallow aquifers. Two-point mixing models based on δD and δ18O allowed the relative extent of evaporation of groundwater sources to be estimated and allowed various water bodies to be broadly distinguished within the aquifer system. Model limitations are discussed, including the spatial and temporal variation in end member compositions. The conservative tracer Cl/Br is used to further discriminate between groundwater bodies. The stable isotopic signatures of groundwaters containing high As and/or high dissolved organic carbon plot both near the local meteoric water line and near more evaporative lines. The varying degrees of evaporation of high As groundwater sources are indicative of differing recharge contributions (and thus indirectly inferred associated organic matter contributions). The presence of high As groundwaters with recharge derived from both local precipitation and relatively evaporated surface water sources, such as ponds or flooded wetlands, are consistent with (but do not provide direct evidence for) models of a potential dual role of surface-derived and sedimentary organic matter in As mobilization.

Atacama perchlorate as an agricultural contaminant in groundwater: Isotopic and chronologic evidence from Long Island, New York

Science.gov (United States)

Böhlke, J.K.; Hatzinger, P.B.; Sturchio, N.C.; Gu, B.; Abbene, I.; Mroczkowski, S.J.

2009-01-01

Perchlorate (ClO4-) is a common groundwater constituent with both synthetic and natural sources. A potentially important source of ClO4- is past agricultural application of ClO4--bearing natural NO3- fertilizer imported from the Atacama Desert, Chile, but evidence for this hasbeenlargely circumstantial. Here we report ClO4- stable isotope data (??37Cl, ??18O, and ??17O), along with other supporting chemical and isotopic environmental tracer data, to document groundwater ClO4- contamination sources and history in parts of Long Island, New York. Sampled groundwaters were oxic and ClO4- apparently was not affected by biodegradation within the aquifers. Synthetic ClO4- was indicated by the isotopic method in groundwater near a fireworks disposal site at a former missile base. Atacama ClO4- was indicated in agricultural and urbanizing areas in groundwaters with apparent ages >20 years. In an agricultural area, ClO4- concentrations and ClO4-/NO3- ratios increased withgroundwaterage, possiblybecauseof decreasing application rates of Atacama NO3- fertilizers and/or decreasing ClO4- concentrations in Atacama NO 3- fertilizers in recent years. Because ClO 4-/NO3- ratios of Atacama NO 3- fertilizers imported in the past (???2 ?? 10-3 mol mol-1) were much higher than the ClO 4-/NO3- ratio of recommended drinking-water limits (7 ?? 10-5 mol mol-1 in New York), ClO4- could exceed drinkingwater limits even where NO3- does not, and where Atacama NO3- was only a minor source of N. Groundwater ClO4- with distinctive isotopic composition was a sensitive indicator of past Atacama NO3- fertilizer use on Long Island and may be common in other areas that received NO3- fertilizers from the late 19th century through the 20th century. ?? 2009 American Chemical Society.

Modeling dissolution and volatilization of LNAPL sources migrating on the groundwater table.

Science.gov (United States)

Kim, Jeongkon; Corapcioglu, M Yavuz

2003-08-01

A vertically averaged two-dimensional model was developed to describe areal spreading and migration of light nonaqueous-phase liquids (LNAPLs) introduced into the subsurface by spills or leaks from underground storage tanks. The NAPL transport model was coupled with two-dimensional contaminant transport models to predict contamination of soil gas and groundwater resulting from a LNAPL migrating on the water table. Numerical solutions were obtained by using the finite-difference method. Simulations and sensitivity analyses were conducted with a LNAPL of pure benzene to study LNAPL migration and groundwater contamination. The model was applied to subsurface contamination by jet fuel. Results indicated that LNAPL migration were affected mostly by volatilization. The generation and movement of the dissolved plume was affected by the geology of the site and the free-product plume. Most of the spilled mass remained as a free LNAPL phase 20 years after the spill. The migration of LNAPL for such a long period resulted in the contamination of both groundwater and a large volume of soil.

Risk mapping of NO/sub 3/-N contamination on groundwater under intensive rice-based cropping systems in the Philippines

International Nuclear Information System (INIS)

Pascual, C.M.; Baga, M.C.S.; Valencia, D.P.

2005-01-01

The groundwater resources in a 265 ha watershed of highly diversified and intensive rice-based environment was endangered to NO/sub 3/-N contamination with spatial degree of influence and temporal vulnerability risks as affected by intensive cropping systems with application of high N-fertilizer and judicious use of groundwater for irrigation. Such nitrate contamination levels are above the World Health Organization's maximum contamination level of 10 ppm for drinking water. Tree-joining, complete cluster analysis of monthly groundwater depths on observation wells revealed three distinct groups of wells differentiated by groundwater depths. Planting of nitrate catch crops such as legumes to reduce groundwater contamination and vigorous information dissemination on ill-effects of high NO/sub 3/-N, as well as groundwater recharging were considered to reduce contamination. However, the groundwater extraction for irrigation is still sustainable due to natural recharging of rainfall and hydraulic connections from surface water along rivers and creeks. The combined-use of GIS and GPS proved useful for spatial and temporal risk mapping assessment on groundwater NO/sub 3/-N vulnerability among other geo-referenced attributes of groundwater and other environmental considerations at the study site. Such systems analysis tools can be used by planners, researchers, extension workers, students and farmers for other sustainable development and environmental risk mapping, assessment, extrapolation analysis and strategic planning of sustainable development of the environment. (author)

Assessment of natural attenuation of ground-water contamination at sites FT03, LF13, and WP14/LF15, Dover Air Force Base, Delaware

Science.gov (United States)

Barbaro, Jeffrey R.

2002-01-01

source areas, and (6) determine whether intrinsic biodegradation is occurring at these sites.The water-quality data indicate that intrinsic biodegradation is occurring at all three sites. The strongest indication of intrinsic biodegradation is the detection of tetrachloroethene and trichloroethene breakdown products within and down-gradient of the source areas. The patterns of electron acceptors and metabolic by-products indicate that contaminant biodegradation has changed the prevailing geochemistry of the surficial aquifer, creating the strongly reducing conditions necessary for chlorinated solvent bio-degradation. Geochemical changes include depleted dissolved oxygen and elevated ferrous iron and methane levels relative to concentrations in uncontaminated zones of the surficial aquifer. At Fire Training Area Three and the Rubble Area Landfill sites, natural attenuation appears to be adequate for controlling the migration of the contaminant plumes. At the third site, the Liquid Waste Disposal and Receiver Station Landfills, the plume is larger and the uncertainty about the effectiveness of natural attenuation in reducing contaminant concentrations and controlling plume migration is greater. Ground-water data indicate, however, that U.S. Environmental Protection Agency maximum contaminant levels were not exceeded in any point-of-compliance wells located along the Base boundary.The information presented in this report led to the development of improved conceptual models for these sites, and to the recognition of four issues that are currently unclear and may need further study. These issues include delineating the areal and vertical extent of the contaminant plumes in greater detail, determining the extent of intrinsic biodegradation downgradient of the Liquid Waste Disposal and Receiver Station Landfills, deter-mining the fate of contaminants in the ground-water discharge areas, and determining the effect of temporal variability in source concentrations and ground-water

Statistical analysis of ground-water contamination at the alert apron and northern landfill areas of Wurtsmith AFB, Michigan. Final report

Energy Technology Data Exchange (ETDEWEB)

Hunter, P.; Naber, S.; Verducci, J.

1988-07-01

Two plumes of contamination are analyzed to determine their extent, composition, and movement. The large number of ground-water monitoring wells sampled over the past eight years at Wurtsmith AFB allow this analysis to be performed directly from empirical data, with minimal assumptions about solute transport mechanisms. Conclusions are drawn about the likely sources of contamination in the two plumes, the adequacy of the data for making risk assessments, and the likely consequences of alternative programs of remediation.

Methodology for and uses of a radiological source term assessment for potential impacts to stormwater and groundwater

International Nuclear Information System (INIS)

Teare, A.; Hansen, K.; DeWilde, J.; Yu, L.; Killey, D.

2001-01-01

A Radiological Source Term Assessment (RSTA) was conducted by Ontario Power Generation Inc. (OPG) at the Pickering Nuclear Generating Station (PNGS). Tritium had been identified in the groundwater at several locations under the station, and OPG initiated the RSTA as part of its ongoing efforts to improve operations and to identify potential sources of radionuclide impact to groundwater and stormwater at the station. The RSTA provides a systematic approach to collecting information and assessing environmental risk for radioactive contaminants based on a ranking system developed for the purpose. This paper provides an overview of the RSTA focusing on the investigative approach and how it was applied. This approach can find application at other generating stations. (author)

Monitoring priority substances, other organic contaminants and heavy metals in a volcanic aquifer from different sources and hydrological processes

International Nuclear Information System (INIS)

Estevez, Esmeralda; Cabrera, María del Carmen; Fernández-Vera, Juan Ramón; Molina-Díaz, Antonio; Robles-Molina, José; Palacios-Díaz, María del Pino

2016-01-01

Irrigation with reclaimed water (R) is necessary to guarantee the sustainability of semi-arid areas. Results obtained during a two years monitoring network (2009–2011) in Gran Canaria are presented, including the analysis of chemical parameters, N and S isotopes, priority substances (2008/105/EC, 2013/39/EU), other organic contaminants and heavy metals in groundwater and R used to irrigate a golf course. The aims of this work are to evaluate the contamination in a volcanic aquifer, relate the presence of organic contaminants and heavy metals with the hydrogeochemistry and identify pollution sources in the area. No priority substance exceeded the EU thresholds for surface water, although seventeen were detected in R. The most frequent compounds were hexachlorobenzene, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. These compounds were detected at low concentration, except chlorpyrifos. Chlorpyrifos ethyl, terbuthylazine, diuron, terbutryn, procymidone, atrazine and propazine exceeded the European threshold concentration for pesticides in groundwater (100 ng L"−"1). Therefore, the priority substances chlorpyrifos ethyl and diuron must be included in monitoring studies. The priority pesticides chlorfenvinphos and diazinon were always detected in R but rarely in groundwater. Besides, the existence of contaminants not related to the current R irrigation has been identified. Absence of environmental problems related to heavy metals can be expected. The relationship among contaminant presence, hydrogeochemistry, including the stable isotopic prints of δ"1"8O, δ"1"5N and δ"3"4S and preferential recharge paths has been described. The coastal well shows high values of EC, nitrate, a variable chemistry, and 50% of organic contaminants detected above 100 ng L"−"1. The well located in the recharge area presents a stable hydrochemistry, the lowest value of δ"1"5N and the lowest contaminants occurrence. The area is an example of a complex volcanic media with

Monitoring priority substances, other organic contaminants and heavy metals in a volcanic aquifer from different sources and hydrological processes

Energy Technology Data Exchange (ETDEWEB)

Estevez, Esmeralda, E-mail: eestevez@proyinves.ulpgc.es [Dpt. Física (GEOVOL), Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Canary Islands (Spain); Agrifood and Phytopathological Laboratory (Cabildo de Gran Canaria), 35413 Arucas, Canary Islands (Spain); Cabrera, María del Carmen, E-mail: mcarmen.cabrera@ulpgc.es [Dpt. Física (GEOVOL), Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Canary Islands (Spain); IMDEA Water Institute, Alcalá de Henares, Madrid (Spain); Fernández-Vera, Juan Ramón, E-mail: jrfernandezv@grancanaria.com [Agrifood and Phytopathological Laboratory (Cabildo de Gran Canaria), 35413 Arucas, Canary Islands (Spain); Molina-Díaz, Antonio, E-mail: amolina@ujaen.es [Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaen, 23071 Jaen (Spain); Robles-Molina, José, E-mail: jroblesmol@gmail.com [Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaen, 23071 Jaen (Spain); Palacios-Díaz, María del Pino, E-mail: mp.palaciosdiaz@ulpgc.es [Dpt. de Patología Animal, Producción Animal, Bromatología y Tecnología de los Alimentos (GEOVOL), Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Canary Islands (Spain)

2016-05-01

Irrigation with reclaimed water (R) is necessary to guarantee the sustainability of semi-arid areas. Results obtained during a two years monitoring network (2009–2011) in Gran Canaria are presented, including the analysis of chemical parameters, N and S isotopes, priority substances (2008/105/EC, 2013/39/EU), other organic contaminants and heavy metals in groundwater and R used to irrigate a golf course. The aims of this work are to evaluate the contamination in a volcanic aquifer, relate the presence of organic contaminants and heavy metals with the hydrogeochemistry and identify pollution sources in the area. No priority substance exceeded the EU thresholds for surface water, although seventeen were detected in R. The most frequent compounds were hexachlorobenzene, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. These compounds were detected at low concentration, except chlorpyrifos. Chlorpyrifos ethyl, terbuthylazine, diuron, terbutryn, procymidone, atrazine and propazine exceeded the European threshold concentration for pesticides in groundwater (100 ng L{sup −1}). Therefore, the priority substances chlorpyrifos ethyl and diuron must be included in monitoring studies. The priority pesticides chlorfenvinphos and diazinon were always detected in R but rarely in groundwater. Besides, the existence of contaminants not related to the current R irrigation has been identified. Absence of environmental problems related to heavy metals can be expected. The relationship among contaminant presence, hydrogeochemistry, including the stable isotopic prints of δ{sup 18}O, δ{sup 15}N and δ{sup 34}S and preferential recharge paths has been described. The coastal well shows high values of EC, nitrate, a variable chemistry, and 50% of organic contaminants detected above 100 ng L{sup −1}. The well located in the recharge area presents a stable hydrochemistry, the lowest value of δ{sup 15}N and the lowest contaminants occurrence. The area is an example of a complex

Assessing Contamination Potential of Nitrate-N in Groundwater of Lanyang Plain

Science.gov (United States)

Liang, Ching-Ping; Tu, Yu-Lin; Lin, Chien-Wen; Jang, Cheng-Shin

2013-04-01

Nitrate-N pollution is often relevant to agricultural activities such as the fertilization of crops. Significant increases in the nitrate-N pollution of groundwater are found in natural recharging zones of Taiwan. The increasing nitrate-N contamination seriously threatens public drinking water supply and human health. Constructing a correct map of aquifer contamination potential is an effective and feasible way to protect groundwater for quality assessment and management. Therefore, in this study, we use DRASTIC model with the help of geographic information system (GIS) to assess and predict the contamination potential of nitrate-N in the aquifer of Lanyang Plain, Taiwan. Seven factors of hydrogeology and hydrology, which includes seven parameters - Depth to groundwater, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity, are considered to carry out this assessment. The validity of the presented model is established by comparing the results with the measured nitrate concentration in wells within the study area. Adjusting factor weightings via the discriminant analysis is performed to improve the assessment and prediction. The analyzed results can provide residents with suggestive strategies against nitrate-N pollution in agricultural regions and government administrators with explicit information of Nitrate-N pollution extents when plans of water resources are considered.

Spreading of Groundwater Contamined by Leached in the Surrounding Area of Piyungan Landfill Bantul District, Yogyakarta Province

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J Sartohadi

2017-07-01

Full Text Available The objectives of this research are: (1 to study the characteristics of aquifer, distribution and chemical types of groundwater in the research area; (2 to measure the consentration of major elements (HC03-, Cl-, S042-, Ca2+, Mg2+, Na+, K+ and minor elements (S2-, NH4+ as indicators of leached contamination in the groundwater; and (3 to establish the spreading of contamined groundwater by leached. The grid sampling method was applied in this research. The grid dimension is 1 cm x 1 cm measured in the 1:25000 scale of Indonesian Topographic Map. The groundwater samples were taken randomly within the grid. Not the whole study area covered by the map was grided but only the surrounding area of Piyungan Landfill and the area lower than Piyungan landfill were grided. The groundwater samples were taken during the rainy season because during the rainy season there were more leached produced from Piyungan Landfill. The groundwater samples were examined their physical and chemical qualities using the legal standard quality in Yogyakarta Province. Spatial analysis using maps and graphics were applied to examine the spreading of contimined groundwater by leached. The spreading of unconfined groundwater in the study area was not equal distributed but it seems to be controlled by the landforms. There were an increasing elements content of Cl-, Ca2+, Mg2+ and HCO3-, as well as dissolved oxygen, NO3- and S2- in the groundwater contamined by leached. The zonation of the spreading of groundwater contamined by leached was categorized into three class, i.e., central (location of landfill, well number 1 0, transisional (well number: 11, 12, 13, 15, and primary (well number: 8, 14, 16, 17, 25, 26 zones. The zonation of groundwater matched with the analysis of groundwater quality by the distance from the Piyungan Landfill.

Assessment of well vulnerability for groundwater source protection based on a solute transport model: a case study from Jilin City, northeast China

Science.gov (United States)

Huan, Huan; Wang, Jinsheng; Lai, Desheng; Teng, Yanguo; Zhai, Yuanzheng

2015-05-01

Well vulnerability assessment is essential for groundwater source protection. A quantitative approach to assess well vulnerability in a well capture zone is presented, based on forward solute transport modeling. This method was applied to three groundwater source areas (Jiuzhan, Hadawan and Songyuanhada) in Jilin City, northeast China. The ratio of the maximum contaminant concentration at the well to the released concentration at the contamination source ( c max/ c 0) was determined as the well vulnerability indicator. The results indicated that well vulnerability was higher close to the pumping well. The well vulnerability in each groundwater source area was low. Compared with the other two source areas, the cone of depression at Jiuzhan resulted in higher spatial variability of c max/ c 0 and lower minimum c max/ c 0 by three orders of magnitude. Furthermore, a sensitivity analysis indicated that the denitrification rate in the aquifer was the most sensitive with respect to well vulnerability. A process to derive a NO3-N concentration at the pumping well is presented, based on determining the maximum nitrate loading limit to satisfy China's drinking-water quality standards. Finally, the advantages, disadvantages and prospects for improving the precision of this well vulnerability assessment approach are discussed.

Characteristics of petroleum-contaminated groundwater during natural attenuation: a case study in northeast China.

Science.gov (United States)

Qian, Hong; Zhang, Yuling; Wang, Jiali; Si, Chaoqun; Chen, Zaixing

2018-01-13

The objective of this study was to investigate a petroleum-contaminated groundwater site in northeast China. We determined the physicochemical properties of groundwater that contained total petroleum hydrocarbons (TPH) with a view to developing a scientifically robust strategy for controlling and remediating pollution of groundwater already contaminated with petroleum. Samples were collected at regular intervals and were analyzed for dissolved oxygen (DO), iron (Fe 3+ ), sulfate (SO 4 2- ), electrical conductivity (Eh), pH, hydrogen carbonate (HCO 3 - ), and enzyme activities of catalase (CAT), peroxidase (HRP), catechol 1,2-dioxygenase (C12O), and catechol 2,3-dioxygenase (C23O). We used factor analysis in SPSS to determine the main environmental characteristics of the groundwater samples. The results confirmed that the study site was slightly contaminated and that TPH levels were decreasing slightly. Some of the physicochemical variables showed regular fluctuations; DO, Fe 3+ , and SO 4 2- contents decreased gradually, while the concentrations of one of the microbial degradation products, HCO 3 - , increased. Microorganism enzyme activities decreased gradually. The microbiological community deteriorated noticeably during the natural attenuation process, so microbiological degradation of pollutants receded gradually. The HCO 3 - content increased and the pH and Eh decreased gradually. The groundwater environment tended to be reducing.

Volatilized tritiated water vapor in the vicinity of exposed tritium contaminated groundwater

International Nuclear Information System (INIS)

Dunn, D.L.; Carlton, B.; Hunter, C.; McAdams, T.

1994-01-01

Water vapor tritium concentrations in air above a known source of tritiated water can be estimated. Estimates should account for the mechanisms of evaporation and condensation at the water surface and water species exchange, and are typically applicable under a broad range of wind, temperature and humidity conditions. An estimate of volatilized tritium water vapor was made for a known outcropping of tritium contaminated groundwater at the Savannah River Site (SRS) old F-Area effluent stream. In order to validate this estimate and the associated dose calculation, sampling equipment was fabricated, tested, and installed at the effluent stream. The estimate and the dose calculation were confirmed using data from samples collected

Environmental Groundwater Vulnerability Assessment in Urban Water Mines (Porto, NW Portugal

Directory of Open Access Journals (Sweden)

Maria José Afonso

2016-11-01

Full Text Available A multidisciplinary approach was developed to estimate urban groundwater vulnerability to contamination combining hydrogeology, hydrogeochemistry, subterranean hydrogeotechnics, groundwater ecotoxicology and isotope tracers. Paranhos and Salgueiros spring waters in Porto City were used as a case study. Historical and current vulnerability scenarios were compared using hydrogeological GIS-based modelling. Potential contamination sources were mapped around the spring galleries. Most of these were point sources and their potential contamination load was moderate. The ecotoxicological assessment indicated a low acute toxicity potential. Groundwater radionuclides appeared to be mainly controlled by geological factors and biomineralisation. Vulnerability maps suggest that most of the area has a moderate to low vulnerability to contamination. However, some surface sources such as sewage systems cause contamination and contribute to increased vulnerability. This integrated approach was demonstrated to be adequate for a better knowledge of urban hydrogeological processes and their dynamics, and highlighted the importance of a vulnerability assessment in urban areas.

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination. Theory and user`s manual, Version 2.0: Revision 2

Energy Technology Data Exchange (ETDEWEB)

Rood, A.S.

1994-06-01

Multimedia exposure assessment of hazardous chemicals and radionuclides requires that all pathways of exposure be investigated. The GWSCREEN model was designed to perform initial screening calculations for groundwater pathway impacts resulting from the leaching of surficial and buried contamination at CERCLA sites identified as low probability hazard at the INEL. In Version 2.0, an additional model was added to calculate impacts to groundwater from the operation of a percolation pond. The model was designed to make best use of the data that would potentially be available. These data include the area and depth of contamination, sorptive properties and solubility limit of the contaminant, depth to aquifer, and the physical properties of the aquifer (porosity, velocity, and dispersivity). For the pond model, data on effluent flow rates and operation time are required. Model output includes the limiting soil concentration such that, after leaching and transport to the aquifer, regulatory contaminant levels in groundwater are not exceeded. Also, groundwater concentration as a function of time may be calculated. The model considers only drinking water consumption and does not include the transfer of contamination to food products due to irrigation with contaminated water. Radiological dose, carcinogenic risk, and the hazard quotient are calculated for the peak time using the user-defined input mass (or activity). Appendices contain sample problems and the source code listing.

Baseline risk assessment for groundwater contamination at the uranium mill tailings site, Gunnison, Colorado

International Nuclear Information System (INIS)

1990-11-01

The Gunnison Baseline Risk Assessment for Groundwater Contamination at the Uranium Mill Tailings Site was performed to determine if long-term use of groundwater from domestic wells near the site has a potential for adverse health effects. The risk assessment was based on the results of sampling domestic wells during 1989--1990. A risk assessment evaluates health risks by comparing the amount of a contaminant taken in by a person with the amount of the contaminant that may be toxic. The Gunnison Risk Assessment used high intake values to estimate the maximum levels a person might be exposed to. The results of the risk assessment are divided into cancer (carcinogenic) risks and non-carcinogenic risks. Five key contaminants were evaluated for adverse health risks: uranium, manganese, lead antimony, and cadmium. Due to the potential health risks and the unavoidable uncertainties associated with limited groundwater and toxicity data, it is prudent public health policy to provide a permanent alternate water supply. Additionally, providing a permanent alternate water supply is cost-effective compared to long-term routine monitoring

Investigation of shallow groundwater contamination near East Fork Poplar Creek, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Carmichael, J.K.

1989-01-01

Alluvial soils of the flood plain of East Fork Poplar Creek in Oak Ridge, Tennessee, are contaminated with mercury and other metals, organic compounds, and radionuclides originating from the Y-12 Plant, a nuclear-processing facility located within the US Department of Energy's Oak Ridge Reservation. Observation wells were installed in the shallow aquifer of the flood plain, and water quality samples were collected to determine if contaminants are present in the shallow groundwater. Groundwater in the shallow aquifer occurs under water-table conditions. Recharge is primarily from precipitation and discharge is to East Fork Poplar Creek. Groundwater levels fluctuate seasonally in response to variations in recharge and evapotranspiration. During extremely dry periods, the water table drops below the base of the shallow aquifer in some flood-plain areas. Contaminants were found in water samples from several of the wells in concentrations which equaled or exceeded drinking-water standards established by the US Environmental Protection Agency are antimony, chromium, lead, mercury, selenium, phenols, and strontium-90. Total and dissolved uranium concentrations exceeded the analytical detection limit in nearly 70% of the wells in the flood plain. The results of water quality determinations demonstrate that elevated concentrations of most trace metals (and possibly organic compounds and radionuclides) were caused by contaminated sediments in the samples. The presence of contaminated sediment in samples is suspected to be the result of borehole contamination during well installation. 21 refs., 20 figs., 6 tabs

Capacitive deionization of arsenic-contaminated groundwater in a single-pass mode.

Science.gov (United States)

Fan, Chen-Shiuan; Liou, Sofia Ya Hsuan; Hou, Chia-Hung

2017-10-01

A single-pass-mode capacitive deionization (CDI) reactor was used to remove arsenic from groundwater in the presence of multiple ions. The CDI reactor involved an applied voltage of 1.2 V and six cell pairs of activated carbon electrodes, each of which was 20 × 30 cm 2 . The results indicate that this method achieved an effluent arsenic concentration of 0.03 mg L -1 , which is lower than the arsenic concentration standard for drinking water and irrigation sources in Taiwan, during the charging stage. Additionally, the ability of the CDI to remove other coexisting ions was studied. The presence of other ions has a significant influence on the removal of arsenic from groundwater. From the analysis of the electrosorption selectivity, the preference for anion removal could be ordered as follows: NO 3 -  > SO 4 2-  > F -  > Cl - >As. The electrosorption selectivity for cations could be ordered as follows: Ca 2+  > Mg 2+  > Na +  ∼ K + . Moreover, monovalent cations can be replaced by divalent cations at the electrode surface in the later period of the electrosorption stage. Consequently, activated carbon-based capacitive deionization is demonstrated to be a high-potential technology for remediation of arsenic-contaminated groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

Energy Technology Data Exchange (ETDEWEB)

Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

2008-01-31

The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used in collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.

Groundwater redox conditions and conductivity in a contaminant plume from geoelectrical investigations

Directory of Open Access Journals (Sweden)

V. Naudet

2004-01-01

Full Text Available Accurate mapping of the electrical conductivity and of the redox potential of the groundwater is important in delineating the shape of a contaminant plume. A map of redox potential in an aquifer is indicative of biodegradation of organic matter and of concentrations of redox-active components; a map of electrical conductivity provides information on the mineralisation of the groundwater. Both maps can be used to optimise the position of pumping wells for remediation. The self-potential method (SP and electrical resistivity tomography (ERT have been applied to the contaminant plume associated with the Entressen landfill in south-east France. The self-potential depends on groundwater flow (electrokinetic contribution and redox conditions ('electro-redox' contribution. Using the variation of the piezometric head in the aquifer, the electrokinetic contribution is removed from the SP signals. A good linear correlation (R2=0.85 is obtained between the residual SP data and the redox potential values measured in monitoring wells. This relationship is used to draw a redox potential map of the overall contaminated site. The electrical conductivity of the subsoil is obtained from 3D-ERT analysis. A good linear correlation (R2=0.91 is observed between the electrical conductivity of the aquifer determined from the 3D-ERT image and the conductivity of the groundwater measured in boreholes. This indicates that the formation factor is nearly homogeneous in the shallow aquifer at the scale of the ERT. From this correlation, a map of the pore water conductivity of the aquifer is obtained. Keywords: self-potential, redox potential, electrical resistivity tomography, fluid conductivity, contaminant plume

An interdisciplinary approach for groundwater management in area contaminated by fluoride in East African Rift System

Science.gov (United States)

Da Pelo, Stefania; Melis, M. Teresa; Dessì, Francesco; Pistis, Marco; Funedda, Antonio; Oggiano, Giacomo; Carletti, Alberto; Soler Gil, Albert; Barbieri, Manuela; Pittalis, Daniele; Ghiglieri, Giorgio

2017-04-01

Groundwater is the main source of fresh water supply for most of the rural communities in Africa (approximately 75% of Africans has confidence in groundwater as their major source of drinking water). Many African countries has affected by high fluoride concentration in groundwater (up to 90 mg/L), generating the contamination of waters, soils and food, in particular in the eastern part of the continent. It seems that fluoride concentration is linked to geology of the Rift Valley: geogenic occurrence of fluoride is often connected to supergenic enrichment due to the weathering of alkaline volcanic rocks, fumaric gases and presence of thermal waters. The H2020 project FLOWERED (de-FLuoridation technologies for imprOving quality of WatEr and agRo-animal products along the East African Rift Valley in the context of aDaptation to climate change) wish to address environmental and health (human and animal) issues associated to the fluoride contamination in the African Rift Valley, in particular in three case study area located in Ethiopia, Tanzania and Kenya. FLOWERED aims to develop an integrated, sustainable and participative water and agriculture management at a cross-boundary catchment scale through a strong interdisciplinary research approach. It implies knowledge of geology, hydrogeology, mineralogy, geochemistry, agronomy, crop and animal sciences, engineering, technological sciences, data management and software design, economics and communication. The proposed approach is based on a detailed knowledge of the hydrogeological setting, with the identification and mapping of the specific geological conditions of water contamination and its relation with the different land uses. The East African Rift System (EARS) groundwater circulation and storage, today already poorly understood, is characterized by a complex arrangement of aquifers. It depends on the type of porosity and permeability created during and after the rock formation, and is strongly conditioned by the

Degradation of sucralose in groundwater and implications for age dating contaminated groundwater.

Science.gov (United States)

Robertson, W D; Van Stempvoort, D R; Spoelstra, J; Brown, S J; Schiff, S L

2016-01-01

The artificial sweetener sucralose has been in use in Canada and the US since about 2000 and in the EU since 2003, and is now ubiquitous in sanitary wastewater in many parts of the world. It persists during sewage treatment and in surface water environments and as such, has been suggested as a powerful tracer of wastewater. In this study, longer-term persistence of sucralose was examined in groundwater by undertaking a series of three sampling snapshots of a well constrained wastewater plume in Canada (Long Point septic system) over a 6-year period from 2008 to 2014. A shrinking sucralose plume in 2014, compared to earlier sampling, during this period when sucralose use was likely increasing, provides clear evidence of degradation. However, depletion of sucralose from a mean of 40 μg/L in the proximal plume zone, occurred at a relatively slow rate over a period of several months to several years. Furthermore, examination of septic tank effluent and impacted groundwater at six other sites in Canada, revealed that sucralose was present in all samples of septic tank effluent (6-98 μg/L, n = 32) and in all groundwater samples (0.7-77 μg/L, n = 64). Even though sucralose degradation is noted in the Long Point plume, its ubiquitous presence in the groundwater plumes at all seven sites implies a relatively slow rate of decay in many groundwater septic plume environments. Thus, sucralose has the potential to be used as an indicator of 'recent' wastewater contamination. The presence of sucralose identifies groundwater that was recharged after 2000 in Canada and the US and after 2003 in the EU and many Asian countries. Copyright © 2015 Elsevier Ltd. All rights reserved.

Screening of emerging contaminants and priority substances (2008/105/EC) in reclaimed water for irrigation and groundwater in a volcanic aquifer (Gran Canaria, Canary Islands, Spain).

Science.gov (United States)

Estévez, Esmeralda; Cabrera, María del Carmen; Molina-Díaz, Antonio; Robles-Molina, José; Palacios-Díaz, María del Pino

2012-09-01

In semiarid regions, reclaimed water can be an important source of emerging pollutants in groundwater. In Gran Canaria Island, reclaimed water irrigation has been practiced for over thirty years and currently represents 8% of water resources. The aim of this study was to monitor contaminants of emerging concern and priority substances (2008/105/EC) in a volcanic aquifer in the NE of Gran Canaria where the Bandama Golf Course has been sprinkled with reclaimed water since 1976. Reclaimed water and groundwater were monitoring quarterly from July 2009 to May 2010. Only 43% of the 183 pollutants analysed were detected: 42 pharmaceuticals, 20 pesticides, 12 polyaromatic hydrocarbons, 2 volatile organic compounds and 2 flame retardants. The most frequent compounds were caffeine, nicotine, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. Concentrations were always below 50 ng L(-1), although some pharmaceuticals and one pesticide, cholrpyrifos ethyl, were occasionally detected at higher concentrations. This priority substance for surface water exceeded the maximum threshold (0.1 μg L(-1)) for pesticide concentration in groundwater (2006/118/EC). Sorption and degradation processes in soil account for more compounds being detected in reclaimed water than in groundwater, and that some contaminants were always detected in reclaimed water, but never in groundwater (flufenamic acid, propyphenazone, terbutryn and diazinon). Furthermore, erythromycin was always detected in reclaimed water (exceeding occasionally 0.1 μg L(-1)), and was detected only once in groundwater. In contrast, some compounds (phenylephrine, nifuroxazide and miconazole) never detected in reclaimed water, were always detected in groundwater. This fact and the same concentration range detected for the groups, regardless of the water origin, indicated alternative contaminant sources (septic tanks, agricultural practices and sewerage breaks). The widespread detection of high adsorption potential compounds

Black Swans and the Effectiveness of Remediating Groundwater Contamination

Science.gov (United States)

Siegel, D. I.; Otz, M. H.; Otz, I.

2013-12-01

Black swans, outliers, dominate science far more than do predictable outcomes. Predictable success constitutes the Black Swan in groundwater remediation. Even the National Research Council concluded that remediating groundwater to drinking water standards has failed in typically complex hydrogeologic settings where heterogeneities and preferential flow paths deflect flow paths obliquely to hydraulic gradients. Natural systems, be they biological or physical, build upon a combination of large-scale regularity coupled to chaos at smaller scales. We show through a review of over 25 case studies that groundwater remediation efforts are best served by coupling parsimonious site characterization to natural and induced geochemical tracer tests to at least know where contamination advects with groundwater in the subsurface. In the majority of our case studies, actual flow paths diverge tens of degrees from anticipated flow paths because of unrecognized heterogeneities in the horizontal direction of transport, let alone the vertical direction. Consequently, regulatory agencies would better serve both the public and the environment by recognizing that long-term groundwater cleanup probably is futile in most hydrogeologic settings except to relaxed standards similar to brownfielding. A Black Swan

Groundwater contaminant plume maps and volumes, 100-K and 100-N Areas, Hanford Site, Washington

Science.gov (United States)

Johnson, Kenneth H.

2016-09-27

This study provides an independent estimate of the areal and volumetric extent of groundwater contaminant plumes which are affected by waste disposal in the 100-K and 100-N Areas (study area) along the Columbia River Corridor of the Hanford Site. The Hanford Natural Resource Trustee Council requested that the U.S. Geological Survey perform this interpolation to assess the accuracy of delineations previously conducted by the U.S. Department of Energy and its contractors, in order to assure that the Natural Resource Damage Assessment could rely on these analyses. This study is based on previously existing chemical (or radionuclide) sampling and analysis data downloaded from publicly available Hanford Site Internet sources, geostatistically selected and interpreted as representative of current (from 2009 through part of 2012) but average conditions for groundwater contamination in the study area. The study is limited in scope to five contaminants—hexavalent chromium, tritium, nitrate, strontium-90, and carbon-14, all detected at concentrations greater than regulatory limits in the past.All recent analytical concentrations (or activities) for each contaminant, adjusted for radioactive decay, non-detections, and co-located wells, were converted to log-normal distributions and these transformed values were averaged for each well location. The log-normally linearized well averages were spatially interpolated on a 50 × 50-meter (m) grid extending across the combined 100-N and 100-K Areas study area but limited to avoid unrepresentative extrapolation, using the minimum curvature geostatistical interpolation method provided by SURFER®data analysis software. Plume extents were interpreted by interpolating the log-normally transformed data, again using SURFER®, along lines of equal contaminant concentration at an appropriate established regulatory concentration . Total areas for each plume were calculated as an indicator of relative environmental damage. These plume

Pollution sources and groundwater quality in the Coastal region of the Yugoslav part of the Danube

International Nuclear Information System (INIS)

Komatina, S.

1997-01-01

In order to access the vulnerability and risk of the aquifer system in the Yugoslav part of the Danube, as the primary source of drinking water for a numerically substantial community, industrial purposes and irrigation, as well as a high concentration of civil, industrial and agricultural activities (hence, a potential source of pollution of the groundwater resources through land occupation and use as well as the disposal of solid and liquid wastes), a great hydro-geophysical exploration was performed. Within the lower part of the plain, exploratory test of Salinac field, near Smederevo town, was particularly investigated. The reason why is because that part is also an area of the mouth of the Velika Morava into the Danube, where Derdap reservoir is located. Task of complex exploration was to delineate the aquifer, obtain appropriate parameters (groundwater level, groundwater chemistry, clay content, filtration characteristics and physical parameters of geological functions), as well as to map the aquifer vulnerability, in order to prevent and moderate a harmful influence of the performed reservoir on the environment (increased groundwater infiltration from the reservoir into surrounding rocks, permanent groundwater level raising, etc.). Based on the results, zoning of the study area according to the aquifer vulnerability has been done. Then, land-use planning and development of strategy for groundwater protection and management was possible. In the paper, not only sources of contamination, characteristics of pollutants and their influence on the groundwater quality was presented, but also content of organic matters, phosphates and nitrogen compounds, etc. Further, means of protection and management are discussed, as well as the appropriate legal regulations. (author)

A national-scale assessment of micro-organic contaminants in groundwater of England and Wales.

Science.gov (United States)

Manamsa, Katya; Crane, Emily; Stuart, Marianne; Talbot, John; Lapworth, Dan; Hart, Alwyn

2016-10-15

A large variety of micro-organic (MO) compounds is used in huge quantities for a range of purposes (e.g. manufacturing, food production, healthcare) and is now being frequently detected in the aquatic environment. Interest in the occurrence of MO contaminants in the terrestrial and aquatic environments continues to grow, as well as in their environmental fate and potential toxicity. However, the contamination of groundwater resources by MOs has a limited evidence base compared to other freshwater resources. Of particular concern are newly 'emerging contaminants' such as pharmaceuticals and lifestyle compounds, particularly those with potential endocrine disrupting properties. While groundwater often has a high degree of protection from pollution due to physical, chemical and biological attenuation processes in the subsurface compared to surface aquatic environments, trace concentrations of a large range of compounds are still detected in groundwater and in some cases may persist for decades due to the long residence times of groundwater systems. This study provides the first national-scale assessment of micro-organic compounds in groundwater in England and Wales. A large set of monitoring data was analysed to determine the relative occurrence and detected concentrations of different groups of compounds and to determine relationships with land-use, aquifer type and groundwater vulnerability. MOs detected including emerging compounds such as caffeine, DEET, bisphenol A, anti-microbial agents and pharmaceuticals as well as a range of legacy contaminants including chlorinated solvents and THMs, petroleum hydrocarbons, pesticides and other industrial compounds. There are clear differences in MOs between land-use types, particularly for urban-industrial and natural land-use. Temporal trends of MO occurrence are assessed but establishing long-term trends is not yet possible. Copyright © 2016 British Geological Survey, NERC. Published by Elsevier B.V. All rights reserved.

Evaluating Contaminant Flux from the Vadose Zone to the Groundwater in the Hanford Central Plateau. SX Tank Farms Case Study

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Last, George V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tartakovsky, Guzel D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-09-01

At the DOE Hanford Site, contaminants were discharged to the subsurface through engineered waste sites in the Hanford Central Plateau. Additional waste was released through waste storage tank leaks. Much of the contaminant inventory is still present within the unsaturated vadose zone sediments. The nature and extent of future groundwater contaminant plumes and the growth or decline of current groundwater plumes beneath the Hanford Central Plateau are a function of the contaminant flux from the vadose zone to the groundwater. In general, contaminant transport is slow through the vadose zone and it is difficult to directly measure contaminant flux in the vadose zone. Predictive analysis, supported by site characterization and monitoring data, was applied using a structured, systems-based approach to estimate the future contaminant flux to groundwater in support of remediation decisions for the vadose zone and groundwater (Truex and Carroll 2013). The SX Tank Farm was used as a case study because of the existing contaminant inventory in the vadose zone, observations of elevated moisture content in portions of the vadose zone, presence of a limited-extent groundwater plume, and the relatively large amount and wide variety of data available for the site. Although the SX Tank Farm case study is most representative of conditions at tank farm sites, the study has elements that are also relevant to other types of disposal sites in the Hanford Central Plateau.

Guidelines for active spreading during in situ chemical oxidation to remediate contaminated groundwater

Science.gov (United States)

The effectiveness of in situ chemical oxidation to remediate contaminated aquifers depends on the extent and duration of contact between the injected treatment chemical and the groundwater contaminant (the reactants). Techniques that inject and extract in the aquifer to ‘ac...

Potassium ferrate treatment of RFETS' contaminated groundwater

International Nuclear Information System (INIS)

1995-01-01

The potassium ferrate treatment study of Rocky Flats Environmental Technology Site (RFETS) groundwater was performed under the Sitewide Treatability Studies Program (STSP). This study was undertaken to determine the effectiveness of potassium ferrate in a water treatment system to remove the contaminants of concern (COCS) from groundwater at the RFETS. Potassium ferrate is a simple salt where the iron is in the plus six valence state. It is the iron at the plus six valence state (Fe +6 ) that makes it an unique water treatment chemical, especially in waters where the pH is greater than seven. In basic solutions where the solubility of the oxides/hydroxides of many of the COCs is low, solids are formed as the pH is raised. By using ferrate these solids are agglomerated so they can be effectively removed by sedimentation in conventional water treatment equipment. The objective of this study was to determine the quality of water after treatment with potassium ferrate and to determine if the Colorado Water Quality Control Commission (CWQCC) discharge limits for the COCs listed in Table 1.0-1 could be met. Radionuclides in the groundwater were of special concern

Bacterial contamination of groundwater in urban area of Karachi

International Nuclear Information System (INIS)

Zubair, A.; Rippey, B.

1999-01-01

Well-water samples (in=193) were collected from urban areas of five districts of Karachi during the period 1993 to 1995 to evaluate its bacteriological quality and their impact on city environment and morbidity patterns of inhabitants. Samples were analyzed by the standard method American Public Health Association. The bacteriological contamination level suggest that the groundwater of Chaahi is mainly affected by contamination of wastewater containing high levels of coliform and faecal coliform bacteria. This study points towards serious need to control the seepage from sewerage system and use of contaminated well-water should be discouraged to reduce the incidence of water-borne diseases in order to improve the quality of life and health. (author)

Particulate Pyrite Autotrophic Denitrification (PPAD) for Remediation of Nitrate-contaminated Groundwater

Science.gov (United States)

Tong, S.; Rodriguez-Gonzalez, L. C.; Henderson, M.; Feng, C.; Ergas, S. J.

2015-12-01

The rapid movement of human civilization towards urbanization, industrialization, and increased agricultural activities has introduced a large amount of nitrate into groundwater. Nitrate is a toxic substance discharged from groundwater to rivers and leads to decreased dissolved oxygen and eutrophication. For this experiment, an electron donor is needed to convert nitrate into non-toxic nitrogen gas. Pyrite is one of the most abundant minerals in the earth's crust making it an ideal candidate as an electron donor. The overall goal of this research was to investigate the potential for pyrite to be utilized as an electron donor for autotrophic denitrification of nitrate-contaminated groundwater. Batch studies of particulate pyrite autotrophic denitrification (PPAD) of synthetic groundwater (100 mg NO3--N L-1) were set up with varying biomass concentration, pyrite dose, and pyrite particle size. Reactors were seeded with mixed liquor volatile suspended solids (VSS) from a biological nitrogen removal wastewater treatment facility. PPAD using small pyrite particles (exhibited substantial nitrate removal rate, lower sulfate accumulation (5.46 mg SO42-/mg NO3--N) and lower alkalinity consumption (1.70 mg CaCO3/mg NO3--N) when compared to SOD (7.54 mg SO42-/mg NO3--N, 4.57 mg CaCO3/mg NO3--N based on stoichiometric calculation). This research revealed that the PPAD process is a promising technique for nitrate-contaminated groundwater treatment and promoted the utilization of pyrite in the field of environmental remediation.

Dissipation of the herbicide oxyfluorfen in subtropical soils and its potential to contaminate groundwater.

Science.gov (United States)

Yen, Jui-Hung; Sheu, Wey-Shin; Wang, Yei-Shung

2003-02-01

The dissipation and mobility of the herbicide oxyfluorfen (2-chloro-alpha,alpha,alpha-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether) in field soil of Taiwan were investigated in the laboratory with six tea garden soils. The dissipation coefficients of oxyfluorfen in soils of different moisture content (30%, 60%, and 90% of soil field capacity) and soil temperature (10 degrees C, 25 degrees C, and 40 degrees C) were studied. Results indicate that the half-life of oxyfluorfen ranged from 72 to 160 days for six tea garden soils. It was found that if the temperature is high, the dissipation rate is rapid, and there is almost no dissipation at 10 degrees C. Possible contamination of groundwater by the herbicide oxyfluorfen was assessed using the behavior assessment model and the groundwater pollution-potential (GWP) model. The results obtained after evaluating the residue and travel time using the GWP model illustrated that oxyfluorfen is not very mobile in soil and may not contaminate groundwater under normal conditions. But in the case of soil of extremely low organic carbon content and coarse texture, oxyfluorfen has the potential to contaminate groundwater less than 3m deep.

Chemical and biological tracers to determine groundwater flow in karstic aquifer, Yucatan Peninsula

Science.gov (United States)

Lenczewski, M.; Leal-Bautista, R. M.; McLain, J. E.

2013-05-01

Little is known about the extent of pollution in groundwater in the Yucatan Peninsula; however current population growth, both from international tourism and Mexican nationals increases the potential for wastewater release of a vast array of contaminants including personal care products, pharmaceuticals (Rx), and pathogenic microorganisms. Pathogens and Rx in groundwater can persist and can be particularly acute in this region where high permeability of the karst bedrock and the lack of top soil permit the rapid transport of contaminants into groundwater aquifers. The objective of this research is to develop and utilize novel biological and chemical source tracking methods to distinguish between different sources of anthropogenic pollution in degraded groundwater. Although several methods have been used successfully to track fecal contamination sources in small scale studies, little is known about their spatial limitations, as source tracking studies rarely include sample collection over a wide geographical area and with different sources of water. In addition, although source tracking methods to distinguish human from animal fecal contamination are widely available, this work has developed source tracking distinguish between separate human populations is highly unique. To achieve this objective, we collected water samples from a series of drinking wells, cenotes (sinkholes), wastewater treatment plants, and injection wells across the Yucatan Peninsula and examine potential source tracers within the collected water samples. The result suggests that groundwater sources impacted by tourist vs. local populations contain different chemical stressors. This work has developed a more detailed understanding of the presence and persistence of personal care products, pharmaceuticals, and fecal indicators in a karstic system; such understanding will be a vital component for the protection Mexican groundwater and human health. Quantification of different pollution sources

Evaluation of in-situ methanotrophic bioremediation for contaminated groundwater, St. Joseph, Michigan. Final report, January 1989-December 1989

International Nuclear Information System (INIS)

McCarty, P.L.; Semprini, L.; Dolan, M.E.; Harmon, T.C.; Just, S.

1990-09-01

A feasibility study of utilizing indigenous bacteria that use methane as a source of cell carbon and energy (methanotrophs) for in-situ bioremediation of groundwater contaminants at the St. Joseph site is summarized. The contaminants, compounds, can be biotransformed by methanotrophic bacteria, which are found in some locations of the site in adequate populations. The process involves stimulating the growth of native populations of methanotrophs by injecting water containing dissolved methane and oxygen into the aquifer. The stimulated population of methanotrophs in turn has the capability to degrade trichloroethylene, 1,2-cis-dichloroethylene, 1,2-trans-dichloroethylene, and vinyl chloride

Risk-Based Management of Contaminated Groundwater: The Role of Geologic Heterogeneity, Exposure and Cancer Risk in Determining the Performance of Aquifer Remediation

International Nuclear Information System (INIS)

Maxwell, R.M.; Carle, S.F.; Tompson, A.F.B.

2000-01-01

The effectiveness of aquifer remediation is typically expressed in terms of a reduction in contaminant concentrations relative to a regulated maximum contaminant level (MCL), and is usually confined by sparse monitoring data and/or simple model calculations. Here, the effectiveness of remediation is examined from a risk-based perspective that goes beyond the traditional MCL concept. A methodology is employed to evaluate the health risk to individuals exposed to contaminated household water that is produced from groundwater. This approach explicitly accounts for differences in risk arising from variability in individual physiology and water use, the uncertainty in estimating chemical carcinogenesis for different individuals, and the uncertainties and variability in contaminant concentrations within groundwater. A hypothetical contamination scenario is developed as a case study in a saturated, alluvial aquifer underlying a real Superfund site. A baseline (unremediated) human exposure and health risk scenario, as induced by contaminated groundwater pumped from this site, is predicted and compared with a similar estimate based upon pump-and-treat exposure intervention. The predicted reduction in risk in the remediation scenario is not an equitable one-that is, it is not uniform to all individuals within a population and varies according to the level of uncertainty in prediction. The importance of understanding the detailed hydrogeologic connections that are established in the heterogeneous geologic regime between the contaminated source, municipal receptors, and remediation wells, and its relationship to this uncertainty is demonstrated. Using two alternative pumping rates, we develop cost-benefit curves based upon reduced exposure and risk to different individuals within the population, under the presence of uncertainty

Groundwater Molybdenum from Emerging Industries in Taiwan.

Science.gov (United States)

Tsai, Kuo-Sheng; Chang, Yu-Min; Kao, Jimmy C M; Lin, Kae-Long

2016-01-01

This study determined the influence of emerging industries development on molybdenum (Mo) groundwater contamination. A total of 537 groundwater samples were collected for Mo determination, including 295 samples from potentially contaminated areas of 3 industrial parks in Taiwan and 242 samples from non-potentially contaminated areas during 2008-2014. Most of the high Mo samples are located downstream from a thin film transistor-liquid crystal display (TFT-LCD) panel factory. Mean groundwater Mo concentrations from potentially contaminated areas (0.0058 mg/L) were significantly higher (p industry and following wastewater batch treatment were 0.788 and 0.0326 mg/L, respectively. This indicates that wastewater containing Mo is a possible source of both groundwater and surface water contamination. Nine samples of groundwater exceed the World Health Organization's suggested drinking water guideline of 0.07 mg/L. A non-carcinogenic risk assessment for Mo in adults and children using the Mo concentration of 0.07 mg/L yielded risks of 0.546 and 0.215, respectively. These results indicate the importance of the development of a national drinking water quality standard for Mo in Taiwan to ensure safe groundwater for use. According to the human health risk calculation, the groundwater Mo standard is suggested as 0.07 mg/L. Reduction the discharge of Mo-contaminated wastewater from factories in the industrial parks is also the important task in the future.

Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

Science.gov (United States)

Lin, Tzu-Yu; Wei, Chia-Cheng; Huang, Chi-Wei; Chang, Chun-Han; Hsu, Fu-Lan; Liao, Vivian Hsiu-Chuan

2016-03-23

Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

Bioremediation Of Groundwater Contaminated Wtih Gasoline Hydrocarbons And Oxygenates Using A Membrane-Based Reactor

Science.gov (United States)

The objective of this study was to operate a novel, field-scale, aerobic bioreactor and assess its performance in the ex situ treatment of groundwater contaminated with gasoline from a leaking underground storage tank in Pascoag, RI. The groundwater contained elevated concentrat...

Management of Ground and Groundwater Contamination on a Compact Site Constrained by Ongoing Activities

International Nuclear Information System (INIS)

Eilbeck, K.E.; Reeve, P.

2009-01-01

Sellafield Site is a compact and complex site which since the 1940's has been home to a range of facilities associated with the production and reprocessing of fissile material. The site contains the UK equivalent of the Chicago Pile-1 reactor, Hanford B Reactor, Rocky Flats Buildings 771 and 774, West Valley Main Process Plant Building, Savannah River Vitrification Plant, Savannah River MOX Plant, Savannah River F Canyon, Hanford 222 Analytical Laboratory, Savannah River K-, L-, and P-Basins, and the Fort St. Vrain Reactor all in an area of approximately 1000 acres. Spent fuel reprocessing is still undertaken on site; however waste management and decommissioning activities are of increasing importance. These include the emptying and removal of fragile ponds and silos containing significant radioactive inventories, the decommissioning of reactors (including the world's first commercial reactor for power generation and the Windscale Piles, the site of a reactor fire in the late 1950's) and the construction of a new generation of vitrification and encapsulation plants. Leaks, spills and on-site disposals during the site's industrial lifetime have resulted in a legacy of fission products and other radionuclides in the ground and groundwater. Volumes of contaminated ground have been estimated as being as much as 18 million m 3 and an estimated below ground inventory of approximately 1.8 E16 Bq. These have all occurred within close proximity to a range of receptors including farm land and the sea. The cramped nature of the facilities on site, overlapping source terms and ongoing decommissioning, waste management and operating activities all raise significant challenges in the management and remediation of contaminated land and groundwater. The strategy to address these challenges includes: 1. Data collection, management and interpretation. The congested nature of the site and the age of some of the monitoring facilities has resulted in particular difficulties. For

Source Water Protection Contaminant Sources

Data.gov (United States)

Iowa State University GIS Support and Research Facility — Simplified aggregation of potential contaminant sources used for Source Water Assessment and Protection. The data is derived from IDNR, IDALS, and US EPA program...

Hydrodynamic analysis of potential groundwater extraction capacity increase: case study of 'Nelt' groundwater source at Dobanovci

Directory of Open Access Journals (Sweden)

Bajić Dragoljub I.

2017-01-01

Full Text Available A comprehensive hydrodynamic analysis of the groundwater regime undertaken to assess the potential for expanding the 'Nelt' groundwater source at Dobanovci, or developing a new groundwater source for a future baby food factory, including the quantification of the impact on the production wells of the nearby 'Pepsi' groundwater source, is presented in the paper. The existing Nelt source is comprised of three active production wells that tap a subartesian aquifer formed in sands and gravelly sands; however, the analysis considers only the two nearest wells. A long-term group pumping test was con-ducted of production wells N-1 and N2 (Nelt source and production wells B-1 and B-2 (Pepsi source, while the piezometric head in the vicinity of these wells was monitored at observation well P-1, which is located in the area considered for Nelt source expansion. Data were collected at maximum pumping capacity of all the production wells. A hydrodynamic model of groundwater flow in the extended area of the Nelt source was generated for the purposes of the comprehensive hydrodynamic analysis. Hydrodynamic prognostic calculations addressed two solution alternatives for the capacity increase over a period of ten years. Licensed Visual MODFLOW Pro software, deemed to be at the very top in this field, was used for the calculations.

An integrated model for assessing the risk of TCE groundwater contamination to human receptors and surface water ecosystems

DEFF Research Database (Denmark)

McKnight, Ursula S.; Funder, S.G.; Rasmussen, J.J.

2010-01-01

The practical implementation of the European Water Framework Directive has resulted in an increased focus on the hyporheic zone. In this paper, an integrated model was developed for evaluating the impact of point sources in groundwater on human health and surface water ecosystems....... This was accomplished by coupling the system dynamics-based decision support system CARO-PLUS to the aquatic ecosystem model AQUATOX using an analytical volatilization model for the stream. The model was applied to a case study where a TCE contaminated groundwater plume is discharging to a stream. The TCE source...... will not be depleted for many decades, however measured and predicted TCE concentrations in surface water were found to be below human health risk management targets. Volatilization rapidly attenuates TCE concentrations in surface water. Thus, only a 300 m stream reach fails to meet surface water quality criteria...

Identification of groundwater nitrate sources in pre-alpine catchments: a multi-tracer approach

Science.gov (United States)

Stoewer, Myriam; Stumpp, Christine

2014-05-01

well as continuously release of nitrogen stored in agricultural soils due to mineralization processes. In all groundwater and river water samples a seasonal variation of nitrate sources and concentration is absent but nitrate in precipitation shows a clear seasonal variation with peaks in spring and fall according to agricultural activity. This points to dilution effects of high nitrate inputs due to the large groundwater volume and mean residence time and highlights the function of soil as initial sink for nitrogen compounds delivered by fertilizer. Even though nitrate contamination was low in the study area, the results emphasize the importance of reducing additional nitrate sources in pre-alpine oxic aquifers. This will maintain the good water quality status of the aquifers and enable its use for drinking water supply.

Source apportionment of groundwater pollution around landfill site in Nagpur, India.

Science.gov (United States)

Pujari, Paras R; Deshpande, Vijaya

2005-12-01

The present work attempts statistical analysis of groundwater quality near a Landfill site in Nagpur, India. The objective of the present work is to figure out the impact of different factors on the quality of groundwater in the study area. Statistical analysis of the data has been attempted by applying Factor Analysis concept. The analysis brings out the effect of five different factors governing the groundwater quality in the study area. Based on the contribution of the different parameters present in the extracted factors, the latter are linked to the geological setting, the leaching from the host rock, leachate of heavy metals from the landfill as well as the bacterial contamination from landfill site and other anthropogenic activities. The analysis brings out the vulnerability of the unconfined aquifer to contamination.

Hydraulic performance of permeable barriers for in situ treatment of contaminated groundwater

International Nuclear Information System (INIS)

Smyth, D.J.A.; Shikaze, S.G.; Cherry, J.A.

1997-01-01

The passive interception and in situ treatment of dissolved contaminants in groundwater by permeable reactive barriers has recently gained favor at an increasing number of sites as an alternative to conventional approaches to groundwater remediation such as the pump-and-treat method. Permeable reactive barriers have two essential functions. The first is that the barriers must be installed in a position such that all of the plume passes through the reactive system. The second function is to achieve acceptable treatment of the contamination by physical, chemical or biological means within or downgradient of the barrier. In this paper, issues associated with the hydraulic performance of permeable reaction barriers are evaluated using a three-dimensional groundwater flow model. The efficiency of plume capture by permeable wall and funnel-and-gate systems is examined for some generic and for site-specific hydrogeologic systems. The results have important implications to decisions pertaining to the selection, design and installation of permeable reactive barrier systems

Dual wall reverse circulation drilling with multi-level groundwater sampling for groundwater contaminant plume delineation at Paducah Gaseous Diffusion Plant, Paducah, Kentucky

International Nuclear Information System (INIS)

Smuin, D.R.; Morti, E.E.; Zutman, J.L.; Pickering, D.A.

1995-01-01

Dual wall reverse circulation (DWRC) drilling was used to drill 48 borings during a groundwater contaminant investigation at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky. This method was selected as an alternative to conventional hollow stem auger drilling for a number of reasons, including the expectation of minimizing waste, increasing the drilling rate, and reducing the potential for cross contamination of aquifers. Groundwater samples were collected from several water-bearing zones during drilling of each borehole. The samples were analyzed for volatile organic compounds using a field gas chromatograph. This approach allowed the investigation to be directed using near-real-time data. Use of downhole geophysical logging, in conjunction with lithologic descriptions of borehole cuttings, resulted in excellent correlation of the geology in the vicinity of the contaminant plume. The total volume of cuttings generated using the DWRC drilling method was less than half of what would have been produced by hollow stem augering; however, the cuttings were recovered in slurry form and had to be dewatered prior to disposal. The drilling rate was very rapid, often approaching 10 ft/min; however, frequent breaks to perform groundwater sampling resulted in an average drilling rate of < 1 ft/min. The time required for groundwater sampling could be shortened by changing the sampling methodology. Analytical results indicated that the drilling method successfully isolated the various water bearing zones and no cross contamination resulted from the investigation

Y-12 Groundwater Protection Program Groundwater Monitoring Data Compendium, Revision 1

Energy Technology Data Exchange (ETDEWEB)

None

2006-12-01

This document is a compendium of water quality and hydrologic characterization data obtained through December 2005 from the network of groundwater monitoring wells and surface water sampling stations (including springs and building sumps) at the U.S. Department of Energy (DOE) Y-12 National Security Complex (Y-12) in Oak Ridge, Tennessee that have been sampled since January 2003. The primary objectives of this document, hereafter referenced as the Y-12 Groundwater Protection Program (GWPP) Compendium, are to: (1) Serve as a single-source reference for monitoring data that meet the requirements of the Y-12 GWPP, as defined in the Y-12 GWPP Management Plan (BWXT Y-12 L.L.C. [BWXT] 2004); (2) Maintain a detailed analysis and evaluation of the monitoring data for each applicable well, spring, and surface water sampling station, with a focus on results for the primary inorganic, organic, and radiological contaminants in groundwater and surface water at Y-12; and (3) Ensure retention of ''institutional knowledge'' obtained over the long-term (>20-year) history of groundwater and surface water monitoring at Y-12 and the related sources of groundwater and surface water contamination. To achieve these goals, the Y-12 GWPP Compendium brings together salient hydrologic, geologic, geochemical, water-quality, and environmental compliance information that is otherwise disseminated throughout numerous technical documents and reports prepared in support of completed and ongoing environmental contamination assessment, remediation, and monitoring activities performed at Y-12. The following subsections provide background information regarding the overall scope and format of the Y-12 GWPP Compendium and the planned approach for distribution and revision (i.e., administration) of this ''living'' document.

Screening of French groundwater for regulated and emerging contaminants.

Science.gov (United States)

Lopez, Benjamin; Ollivier, Patrick; Togola, Anne; Baran, Nicole; Ghestem, Jean-Philippe

2015-06-15

Nationwide screening of 411 emerging contaminants and other regulated compounds, including parent molecules and transformation products (TPs) having various uses and origins, was done at 494 groundwater sites throughout France during two sampling campaigns in the Spring and the Fall of 2011. One hundred and eighty substances (44% of the targeted compounds) were quantified in at least one sampling point. These included pharmaceuticals, industrial products, pesticides, their transformation products and other emerging compounds. Fifty-five compounds were quantified in more than 1% of the samples. Both regulated and emerging compounds were found. Among the unregulated compounds, acetaminophen, carbamazepine, perfluorinated compounds, dioxins/furans, tolyltriazole, bisphenol A, triazine transformation products, and caffeine were quantified in more than 10% of the samples analyzed. Concentrations exceeding the threshold of toxicological concern of 0.1 μg/L were found for tolyltriazole, bisphenol A and some of the triazine transformation products (DEDIA). These new results should help the water resource managers and environmental regulators develop sound policies regarding the occurrence and distribution of regulated and emerging contaminants in groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing regional groundwater stress for nations using multiple data sources with the groundwater footprint

International Nuclear Information System (INIS)

Gleeson, Tom; Wada, Yoshihide

2013-01-01

Groundwater is a critical resource for agricultural production, ecosystems, drinking water and industry, yet groundwater depletion is accelerating, especially in a number of agriculturally important regions. Assessing the stress of groundwater resources is crucial for science-based policy and management, yet water stress assessments have often neglected groundwater and used single data sources, which may underestimate the uncertainty of the assessment. We consistently analyze and interpret groundwater stress across whole nations using multiple data sources for the first time. We focus on two nations with the highest national groundwater abstraction rates in the world, the United States and India, and use the recently developed groundwater footprint and multiple datasets of groundwater recharge and withdrawal derived from hydrologic models and data synthesis. A minority of aquifers, mostly with known groundwater depletion, show groundwater stress regardless of the input dataset. The majority of aquifers are not stressed with any input data while less than a third are stressed for some input data. In both countries groundwater stress affects agriculturally important regions. In the United States, groundwater stress impacts a lower proportion of the national area and population, and is focused in regions with lower population and water well density compared to India. Importantly, the results indicate that the uncertainty is generally greater between datasets than within datasets and that much of the uncertainty is due to recharge estimates. Assessment of groundwater stress consistently across a nation and assessment of uncertainty using multiple datasets are critical for the development of a science-based rationale for policy and management, especially with regard to where and to what extent to focus limited research and management resources. (letter)

Case studies illustrating in-situ remediation methods for soil and groundwater contaminated with petrochemicals

Energy Technology Data Exchange (ETDEWEB)

Dixon, Robert A; Lance, P E; Downs, A; Kier, Brian P [EMCON Northwest Inc., Portland, OR (United States)

1994-12-31

Four case studies of successful in-situ remediation are summarized illustrating cost-effective methods to remediate soil and groundwater contaminated with volatile and non-volatile petrochemicals. Each site is in a different geologic environment with varying soil types and with and without groundwater impact. The methods described include vadose zone vapor extraction, high-vacuum vapor extraction combined with groundwater tab.le depression, air sparging with groundwater recovery and vapor extraction, and bio remediation of saturated zone soils using inorganic nutrient and oxygen addition

Case studies illustrating in-situ remediation methods for soil and groundwater contaminated with petrochemicals

Energy Technology Data Exchange (ETDEWEB)

Dixon, Robert A.; Lance, P.E.; Downs, A.; Kier, Brian P. [EMCON Northwest Inc., Portland, OR (United States)

1993-12-31

Four case studies of successful in-situ remediation are summarized illustrating cost-effective methods to remediate soil and groundwater contaminated with volatile and non-volatile petrochemicals. Each site is in a different geologic environment with varying soil types and with and without groundwater impact. The methods described include vadose zone vapor extraction, high-vacuum vapor extraction combined with groundwater tab.le depression, air sparging with groundwater recovery and vapor extraction, and bio remediation of saturated zone soils using inorganic nutrient and oxygen addition

Characterization of arsenite-oxidizing bacteria isolated from arsenic-contaminated groundwater of West Bengal.

Science.gov (United States)

Paul, Dhiraj; Poddar, Soumya; Sar, Pinaki

2014-01-01

Nine arsenic (As)-resistant bacterial strains isolated from As-rich groundwater samples of West Bengal were characterized to elucidate their potential in geomicrobial transformation and bioremediation aspects. The 16S rRNA gene-based phylogenetic analysis revealed that the strains were affiliated with genera Actinobacteria, Microbacterium, Pseudomonas and Rhizobium. The strains exhibited high resistance to As [Minimum inhibitory concentration (MIC) ≥ 10 mM As(3+) and MIC ≥ 450 mM As(5+)] and other heavy metals, e.g., Cu(2+), Cr(2+), Ni(2+), etc. (MIC ≥ 2 mM) as well as As transformation (As(3+) oxidation and As(5+) reduction) capabilities. Their ability to utilize diverse carbon source(s) including hydrocarbons and different alternative electron acceptor(s) (As(5+), SO4(2-), S2O3(2-), etc.) during anaerobic growth was noted. Growth at wide range of pH, temperature and salinity, production of siderophore and biofilm were observed. Together with these, growth pattern and transformation kinetics indicated a high As(3+) oxidation activity of the isolates Rhizobium sp. CAS934i, Microbacterium sp. CAS905i and Pseudomonas sp. CAS912i. A positive relation between high As(3+) resistance and As(3+) oxidation and the supportive role of As(3+) in bacterial growth was noted. The results highlighted As(3+) oxidation process and metabolic repertory of strains indigenous to contaminated groundwater and indicates their potential in As(3+) detoxification. Thus, such metabolically well equipped bacterial strains with highest As(3+) oxidation activities may be used for bioremediation of As contaminated water and effluents in the near future.

Impacts of physical and chemical aquifer heterogeneity on basin-scale solute transport: Vulnerability of deep groundwater to arsenic contamination in Bangladesh

Science.gov (United States)

Michael, Holly A.; Khan, Mahfuzur R.

2016-12-01

Aquifer heterogeneity presents a primary challenge in predicting the movement of solutes in groundwater systems. The problem is particularly difficult on very large scales, across which permeability, chemical properties, and pumping rates may vary by many orders of magnitude and data are often sparse. An example is the fluvio-deltaic aquifer system of Bangladesh, where naturally-occurring arsenic (As) exists over tens of thousands of square kilometers in shallow groundwater. Millions of people in As-affected regions rely on deep (≥150 m) groundwater as a safe source of drinking water. The sustainability of this resource has been evaluated with models using effective properties appropriate for a basin-scale contamination problem, but the extent to which preferential flow affects the timescale of downward migration of As-contaminated shallow groundwater is unknown. Here we embed detailed, heterogeneous representations of hydraulic conductivity (K), pumping rates, and sorptive properties (Kd) within a basin-scale numerical groundwater flow and solute transport model to evaluate their effects on vulnerability and deviations from simulations with homogeneous representations in two areas with different flow systems. Advective particle tracking shows that heterogeneity in K does not affect average travel times from shallow zones to 150 m depth, but the travel times of the fastest 10% of particles decreases by a factor of ∼2. Pumping distributions do not strongly affect travel times if irrigation remains shallow, but increases in the deep pumping rate substantially reduce travel times. Simulation of advective-dispersive transport with sorption shows that deep groundwater is protected from contamination over a sustainable timeframe (>1000 y) if the spatial distribution of Kd is uniform. However, if only low-K sediments sorb As, 30% of the aquifer is not protected. Results indicate that sustainable management strategies in the Bengal Basin should consider impacts of both

Monitoring for Pesticides in Groundwater and Surface Water in Nevada, 2008

Science.gov (United States)

Thodal, Carl E.; Carpenter, Jon; Moses, Charles W.

2009-01-01

Commercial pesticide applicators, farmers, and homeowners apply about 1 billion pounds of pesticides annually to agricultural land, non-crop land, and urban areas throughout the United States (Gilliom and others, 2006, p. 1). The U.S. Environmental Protection Agency (USEPA) defines a pesticide as any substance used to kill or control insects, weeds, plant diseases, and other pest organisms. Although there are important benefits from the proper use of pesticides, like crop protection and prevention of human disease outbreaks, there are also risks. One risk is the contamination of groundwater and surface-water resources. Data collected during 1992-2001 from 51 major hydrologic systems across the United States indicate that one or more pesticide or pesticide breakdown product was detected in more than 50 percent of 5,057 shallow (less than 20 feet below land surface) wells and in all of the 186 stream sites that were sampled in agricultural and urban areas (Gilliom and others, 2006, p. 2-4). Pesticides can contaminate surface water and groundwater from both point sources and non-point sources. Point sources are from specific locations such as spill sites, disposal sites, pesticide drift during application, and application of pesticides to control aquatic pests. Non-point sources represent the dominant source of surface water and groundwater contamination and may include agricultural and urban runoff, erosion, leaching from application sites, and precipitation that has become contaminated by upwind applications. Pesticides typically enter surface water when rainfall or irrigation exceeds the infiltration capacity of soil and resulting runoff then transports pesticides to streams, rivers, and other surface-water bodies. Contamination of groundwater may result directly from spills near poorly sealed well heads and from pesticide applications through improperly designed or malfunctioning irrigation systems that also are used to apply pesticides (chemigation; Carpenter and

Use of Short Chained Alkylphenols (SCAP in Analysis of Transport Behaviour of Oil Contaminated Groundwater

Directory of Open Access Journals (Sweden)

M. Sauter

2002-06-01

Full Text Available Shortchained alkylphenols (SCAP represent a main constituent of crude oil and coal liquefaction products. Due to their specific oil/water partitioning behaviour and high aqueous solubility they can be detected in oil exploitation waters and groundwaters affected by various spills near oil pipelines, oil exploitation sites and coal liquefaction plants. New efficient and powerful analytical techniques have been developed that allow the identification of all 34 individual compounds (C0-C3 without derivatisation and in complex matrices. Due to the different physico-chemical properties of the SCAP, differential transport behaviour in groundwater can be observed, changing the relative concentrations of SCAP downgradient in space and time. These characteristic ratios can be employed to derive information on migration direction and the ageing of the source of contamination. A case study is presented to illustrate the use of this new tool.

Groundwater-soil-crop relationship with respect to arsenic contamination in farming villages of Bangladesh - A preliminary study

International Nuclear Information System (INIS)

Kurosawa, Kiyoshi; Egashira, Kazuhiko; Tani, Masakazu; Jahiruddin, M.; Moslehuddin, Abu Zofar Md.; Rahman, Zulfikar Md.

2008-01-01

To clarify the groundwater-soil-crop relationship with respect to arsenic (As) contamination, As concentration was measured in tubewell (TW) water, surface soil from farmyards and paddy fields, and fresh taro (Colocasia esculenta) leaves from farmyards in the farming villages of Bangladesh. The As concentration in TW water from farmyards was at least four times higher than the Bangladesh drinking water standard, and the concentration in fresh taro leaves was equal to or higher than those reported previously for leafy vegetables in Bangladesh. As concentration of surface soils in both farmyards and paddy fields was positively correlated with that of the TW water. Further, the concentration in surface soil was positively correlated with levels in fresh taro leaves in the farmyard. This study, therefore, clarified the groundwater-soil-crop relationship in farmyards and the relationship between groundwater-soil in paddy fields to assess the extent of As contamination in Bangladeshi villages. - By extracting arsenic contaminated groundwater from a well, surface soil surrounding the well and crops planted in the surface soil became contaminated with arsenic

In situ disinfection of sewage contaminated shallow groundwater: a feasibility study.

Science.gov (United States)

Bailey, Morgan M; Cooper, William J; Grant, Stanley B

2011-11-01

Sewage-contaminated shallow groundwater is a potential cause of beach closures and water quality impairment in marine coastal communities. In this study we set out to evaluate the feasibility of several strategies for disinfecting sewage-contaminated shallow groundwater before it reaches the coastline. The disinfection rates of Escherichia coli (EC) and enterococci bacteria (ENT) were measured in mixtures of raw sewage and brackish shallow groundwater collected from a coastal community in southern California. Different disinfection strategies were explored, ranging from benign (aeration alone, and aeration with addition of brine) to aggressive (chemical disinfectants peracetic acid (PAA) or peroxymonosulfate (Oxone)). Aeration alone and aeration with brine did not significantly reduce the concentration of EC and ENT after 6 h of exposure, while 4-5 mg L(-1) of PAA or Oxone achieved >3 log reduction after 15 min of exposure. Oxone disinfection was more rapid at higher salinities, most likely due to the formation of secondary oxidants (e.g., bromine and chlorine) that make this disinfectant inappropriate for marine applications. Using a Lagrangian modeling framework, we identify several factors that could influence the performance of in-situ disinfection with PAA, including the potential for bacterial regrowth, and the non-linear dependence of disinfection rate upon the residence time of water in the shallow groundwater. The data and analysis presented in this paper provide a framework for evaluating the feasibility of in-situ disinfection of shallow groundwater, and elucidate several topics that warrant further investigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Assessment of ground-water contamination from a leaking underground storage tank at a defense supply center near Richmond, Virginia

International Nuclear Information System (INIS)

Powell, J.D.; Wright, W.G.

1990-01-01

During 1988-89, 24 wells were installed in the vicinity of the post-exchange gasoline station on the Defense General Supply Center, near Richmond, Virginia, to collect and analyze groundwater samples for the presence of gasoline contamination from a leaking underground storage tank. Concentrations of total petroleum hydrocarbons and benzene were as high as 8.2 mg/L and 9,000 microg/L, respectively, in water from wells in the immediate vicinity of the former leaking tank, and benzene concentrations were as high as 2,300 microg/L in a well 600 ft down gradient from the gasoline station. Groundwater flow rate are estimated to be about 60 to 80 ft/yr; on the basis of these flow rates, the contaminants may have been introduced into the groundwater as long as 7-10 yrs ago. Groundwater might infiltrate a subsurface storm sewer, where the sewer is below the water table, and discharge into a nearby stream. Preliminary risk assessment for the site identified no potential human receptors to the groundwater contamination because there were no groundwater users identified in the area. Remediation might be appropriate if exposure of future potential users is concern. Alternatives discussed for remediation of groundwater contamination in the upper aquifer at the PX Service Station include no-action, soil vapor extraction, and groundwater pumping and treatment alternatives

Analysis of BTEX groundwater concentrations from surface spills associated with hydraulic fracturing operations.

Science.gov (United States)

Gross, Sherilyn A; Avens, Heather J; Banducci, Amber M; Sahmel, Jennifer; Panko, Julie M; Tvermoes, Brooke E

2013-04-01

Concerns have arisen among the public regarding the potentialfor drinking-water contamination from the migration of methane gas and hazardous chemicals associated with hydraulic fracturing and horizontal drilling. However, little attention has been paid to the potentialfor groundwater contamination resulting from surface spills from storage and production facilities at active well sites. We performed a search for publically available data regarding groundwater contamination from spills at ULS. drilling sites. The Colorado Oil and Gas Conservation Commission (COGCC) database was selected for further analysis because it was the most detailed. The majority ofspills were in Weld County, Colorado, which has the highest density of wells that used hydraulic fracturing for completion, many producing both methane gas and crude oil. We analyzed publically available data reported by operators to the COGCC regarding surface spills that impacted groundwater From July 2010 to July 2011, we noted 77 reported surface spills impacting the groundwater in Weld County, which resulted in surface spills associated with less than 0.5% of the active wells. The reported data included groundwater samples that were analyzed for benzene, toluene, ethylbenzene, andxylene (BTEX) components of crude oil. For groundwater samples taken both within the spill excavation area and on the first reported date of sampling, the BTEX measurements exceeded National Drinking Water maximum contaminant levels (MCLs) in 90, 30, 12, and 8% of the samples, respectively. However, actions taken to remediate the spills were effective at reducing BJTEX levels, with at least 84% of the spills reportedly achieving remediation as of May 2012. Our analysis demonstrates that surface spills are an important route of potential groundwater contamination from hydraulic fracturing activities and should be a focus of programs to protect groundwater While benzene can occur naturally in groundwater sources, spills and migration

Modelling tools for integrating geological, geophysical and contamination data for characterization of groundwater plumes

DEFF Research Database (Denmark)

Balbarini, Nicola

the contaminant plume in a shallow and a deep plume. These plumes have different chemical characteristics and different migration paths to the stream. This has implications for the risk assessment of the stream and groundwater in the area. The difficulty of determining groundwater flow paths means that it is also...... receptors, including streams. Key risk assessment parameters, such as contaminant mass discharge estimates, and tools are then used to evaluate the risk. The cost of drilling often makes investigations of large and/or deep contaminant plumes unfeasible. For this reason, it is important to develop cost...... organic compounds, including pharmaceutical compounds and chlorinated ethenes. The correlation between DCIP and organic compounds is indirect and depends on the chemical composition of the contaminant plume and the transport processes. Thus, the correlations are site specific and may change between...

Functional gene array-based analysis of microbial community structure in groundwaters with a gradient of contaminant levels

Energy Technology Data Exchange (ETDEWEB)

Waldron, P.J.; Wu, L.; Van Nostrand, J.D.; Schadt, C.W.; Watson, D.B.; Jardine, P.M.; Palumbo, A.V.; Hazen, T.C.; Zhou, J.

2009-06-15

To understand how contaminants affect microbial community diversity, heterogeneity, and functional structure, six groundwater monitoring wells from the Field Research Center of the U.S. Department of Energy Environmental Remediation Science Program (ERSP; Oak Ridge, TN), with a wide range of pH, nitrate, and heavy metal contamination were investigated. DNA from the groundwater community was analyzed with a functional gene array containing 2006 probes to detect genes involved in metal resistance, sulfate reduction, organic contaminant degradation, and carbon and nitrogen cycling. Microbial diversity decreased in relation to the contamination levels of the wells. Highly contaminated wells had lower gene diversity but greater signal intensity than the pristine well. The microbial composition was heterogeneous, with 17-70% overlap between different wells. Metal-resistant and metal-reducing microorganisms were detected in both contaminated and pristine wells, suggesting the potential for successful bioremediation of metal-contaminated groundwaters. In addition, results of Mantel tests and canonical correspondence analysis indicate that nitrate, sulfate, pH, uranium, and technetium have a significant (p < 0.05) effect on microbial community structure. This study provides an overall picture of microbial community structure in contaminated environments with functional gene arrays by showing that diversity and heterogeneity can vary greatly in relation to contamination.

Laboratory evaluation of the potential for in situ treatment of chromate-contaminated groundwater by chemical precipitation

International Nuclear Information System (INIS)

Thornton, E.C.; Beck, M.A.; Jurgensmeier, C.A.

1995-03-01

The objective of this paper is to present the results of a series of small-scale batch tests performed to assess the effectiveness of chemical precipitation in the remediation of chromate-contaminated groundwater. These tests involved treatment of chromate solutions with ferrous and sulfide ions. In addition, tests were conducted that involved treatment of mixtures of chromate-contaminated groundwater and uncontaminated soil with the ferrous ion. A combination of ferrous sulfate and sodium sulfide was also tested in the groundwater treatment tests, since this approach has been shown to be an efficient method for treating electroplating wastewaters

Transport of contaminated groundwater to a river

International Nuclear Information System (INIS)

Zeevaert, T.

1990-09-01

Scenario B7 deals with the discharges of Cs-137, Sr-90, Pu-239 and Np-237 with the groundwater from an aquifer into a river, through the river sediment. The contamination of agricultural soil, brought about through the dredging of top sediment from the river, was also considered. Four models participated in this exercise, providing best estimate values. Only one model supplied uncertainty estimates. Brief descriptions of the models and their aims are given. the modelling of the processes taken into account for the computation of the radionuclide concentrations in river and soil compartments are described and the input parameter values are given. The model results are discussed and the reasons for the differences between the models are explained. Important discrepancies were observed. As far as the steady-state concentrations are concerned they were due to differences in the parameter values and transfer processes considered. The time-dependent concentration values depended strongly on the approach adopted for the modelling of the migration of the nuclides through the deep sediment in the source region. The major source of uncertainty pointed out by the model which performed an uncertainty analysis, was the distribution coefficient in the deep sediment. The conclusions and recommendations for improvement of the models, given at the end of the report, accentuate the lack of understanding of the phenomena occurring at the geosphere-biosphere interface and the importance of good communications between scientists of different disciplines. (au)

Tracing the factors responsible for arsenic enrichment in groundwater of the middle Gangetic Plain, India: a source identification perspective.

Science.gov (United States)

Kumar, Pankaj; Kumar, Manish; Ramanathan, A L; Tsujimura, Maki

2010-04-01

Arsenic contamination in groundwater is of increasing concern because of its high toxicity and widespread occurrence. This study is an effort to trace the factors responsible for arsenic enrichment in groundwater of the middle Gangetic Plain of India through major ion chemistry, arsenic speciation, sediment grain-size analyses, and multivariate statistical techniques. The study focuses on the distinction between the contributions of natural weathering and anthropogenic inputs of arsenic with its spatial distribution and seasonal variations in the plain of the state Bihar of India. Thirty-six groundwater and one sediment core samples were collected in the pre-monsoon and post-monsoon seasons. Various graphical plots and statistical analysis were carried out using chemical data to enable hydrochemical evaluation of the aquifer system based on the ionic constituents, water types, hydrochemical facies, and factors controlling groundwater quality. Results suggest that the groundwater is characterized by slightly alkaline pH with moderate to strong reducing nature. The general trend of various ions was found to be Ca(2+) > Na(+) > Mg(2+) > K(+) > NH(4) (+); and HCO(3) (-) > Cl(-) > SO(4) (2-) > NO(3) (-) > PO(4) (3-) > F(-) in both seasons. Spatial and temporal variations showed a slightly higher arsenic concentration in the pre-monsoon period (118 microg/L) than in the post-monsoon period (114 microg/L). Results of correlation analyses indicate that arsenic contamination is strongly associated with high concentrations of Fe, PO(4) (3-), and NH(4) (+) but relatively low Mn concentrations. Further, the enrichment of arsenic is more prevalent in the proximity of the Ganges River, indicating that fluvial input is the main source of arsenic. Grain size analyses of sediment core samples revealed clay (fine-grained) strata between 4.5 and 7.5 m deep that govern the vertical distribution of arsenic. The weathering of carbonate and silicate minerals along with surface-groundwater

PERMEABLE REACTIVE BARRIERS FOR IN-SITU TREATMENT OF ARSENIC-CONTAMINATED GROUNDWATER

Science.gov (United States)

Laboratory and field research has shown that permeable reactive barriers (PRBs) containing a variety of materials can treat arsenic (As) contaminated groundwater. Sites where these PRBs are located include a mine tailings facility, fertilizer and chemical manufacturing sites, a...

Studies Related to the Role of Colloids on the Transport of Some Radio Contaminants in Groundwater

International Nuclear Information System (INIS)

Mekhemar, H.S.A.

2012-01-01

The safety of a radioactive waste repository is related to its capacity to confine radioactivity and isolate it from biosphere. The most likely process that can lead to the release of radionuclides from a repository to the geosphere is transport by groundwater. The transport and distribution of radionuclides in groundwater or through geologic media depend on the radioactive source, the physicochemical forms of radionuclides and interactions of radionuclides with other components present in the groundwater. Colloids naturally exist in groundwater aquifers and can significantly impact contaminant migration rate. The presence of colloids affects contaminant transport in aquifers either by facilitation or retardation. The effect of the presence of colloid (Al 2 O 3 ) on the sorption characteristics of Co 2+ and Cs + , as two of the most important radionuclides commonly encountered in the Egyptian waste streams, onto yellow sand and clay taken from Inshas site was studied. Based on the obtained results, the maximum sorption capacity of Cs + and Co 2+ in presence of colloid was higher than sorption in absence of colloid but the sorption capacity of clay was found to be greater than that of yellow sand for both ions in absence and presence of colloid. Sorption capacity (q) increased by increasing initial metal ion concentration. The increasing temperature from 25 to 65 degree C leads to slight decrease in the sorption of Cs ions while lead to increase in sorption of Co ions. The kinetic data could be successfully interpreted by simplified second order kinetic expression. The rate constants and the theoretical equilibrium Sorption capacities were calculated for studied cases. It was demonstrated from column experiments that colloid presence influences radionuclides transport through fixed bed yellow sand column. Al 2 O 3 and Fe 2 O 3 colloids reduce the migration of Cs + and Co 2+ ions in all studied cases. From the results of desorption experiments it can be concluded

Screening tool to evaluate the vulnerability of down-gradient receptors to groundwater contaminants from uncapped landfills

Energy Technology Data Exchange (ETDEWEB)

Baker, Ronald J.; Reilly, Timothy J. [U.S. Geological Survey, 3450 Princeton Pike, Suite 110, Lawrenceville, NJ 08648 (United States); Lopez, Anthony [Bayer-Risse Engineering, Inc., 78 Route 173 West, Suite 6, Hampton, NJ 08827 (United States); Romanok, Kristin [U.S. Geological Survey, 3450 Princeton Pike, Suite 110, Lawrenceville, NJ 08648 (United States); Wengrowski, Edward W. [New Jersey Pinelands Commission, 15 Springfield Road, New Lisbon, NJ 08064 (United States)

2015-09-15

Highlights: • A spreadsheet-based risk screening tool for groundwater affected by landfills is presented. • Domenico solute transport equations are used to estimate downgradient contaminant concentrations. • Landfills are categorized as presenting high, moderate or low risks. • Analysis of parameter sensitivity and examples of the method’s application are given. • The method has value to regulators and those considering redeveloping closed landfills. - Abstract: A screening tool for quantifying levels of concern for contaminants detected in monitoring wells on or near landfills to down-gradient receptors (streams, wetlands and residential lots) was developed and evaluated. The tool uses Quick Domenico Multi-scenario (QDM), a spreadsheet implementation of Domenico-based solute transport, to estimate concentrations of contaminants reaching receptors under steady-state conditions from a constant-strength source. Unlike most other available Domenico-based model applications, QDM calculates the time for down-gradient contaminant concentrations to approach steady state and appropriate dispersivity values, and allows for up to fifty simulations on a single spreadsheet. Sensitivity of QDM solutions to critical model parameters was quantified. The screening tool uses QDM results to categorize landfills as having high, moderate and low levels of concern, based on contaminant concentrations reaching receptors relative to regulatory concentrations. The application of this tool was demonstrated by assessing levels of concern (as defined by the New Jersey Pinelands Commission) for thirty closed, uncapped landfills in the New Jersey Pinelands National Reserve, using historic water-quality data from monitoring wells on and near landfills and hydraulic parameters from regional flow models. Twelve of these landfills are categorized as having high levels of concern, indicating a need for further assessment. This tool is not a replacement for conventional numerically

Monitoring priority substances, other organic contaminants and heavy metals in a volcanic aquifer from different sources and hydrological processes.

Science.gov (United States)

Estevez, Esmeralda; Cabrera, María del Carmen; Fernández-Vera, Juan Ramón; Molina-Díaz, Antonio; Robles-Molina, José; Palacios-Díaz, María del Pino

2016-05-01

Irrigation with reclaimed water (R) is necessary to guarantee the sustainability of semi-arid areas. Results obtained during a two years monitoring network (2009-2011) in Gran Canaria are presented, including the analysis of chemical parameters, N and S isotopes, priority substances (2008/105/EC, 2013/39/EU), other organic contaminants and heavy metals in groundwater and R used to irrigate a golf course. The aims of this work are to evaluate the contamination in a volcanic aquifer, relate the presence of organic contaminants and heavy metals with the hydrogeochemistry and identify pollution sources in the area. No priority substance exceeded the EU thresholds for surface water, although seventeen were detected in R. The most frequent compounds were hexachlorobenzene, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. These compounds were detected at low concentration, except chlorpyrifos. Chlorpyrifos ethyl, terbuthylazine, diuron, terbutryn, procymidone, atrazine and propazine exceeded the European threshold concentration for pesticides in groundwater (100ngL(-1)). Therefore, the priority substances chlorpyrifos ethyl and diuron must be included in monitoring studies. The priority pesticides chlorfenvinphos and diazinon were always detected in R but rarely in groundwater. Besides, the existence of contaminants not related to the current R irrigation has been identified. Absence of environmental problems related to heavy metals can be expected. The relationship among contaminant presence, hydrogeochemistry, including the stable isotopic prints of δ(18)O, δ(15)N and δ(34)S and preferential recharge paths has been described. The coastal well shows high values of EC, nitrate, a variable chemistry, and 50% of organic contaminants detected above 100ngL(-1). The well located in the recharge area presents a stable hydrochemistry, the lowest value of δ(15)N and the lowest contaminants occurrence. The area is an example of a complex volcanic media with several

Assessing the impact of dairy waste lagoons on groundwater quality using a spatial analysis of vadose zone and groundwater information in a coastal phreatic aquifer.

Science.gov (United States)