Arsenic in Groundwater in Eastern New England:  Occurrence, Controls, and Human Health Implications

Ayotte, Joseph D.; Montgomery, Denise; Flanagan, Sarah M.; Robinson, Keith

doi:10.1021/es026211g

Cited by 210 publications

(144 citation statements)

References 14 publications

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“…The wider range of total As concentrations on the sediments is consistent with the hypothesis that As not associated with coatings on sediment grains is in the interior of mineral grains and that the range of values reflects heterogeneity in the distribution of these grains in the sediments. Studies of As in drinking water supplies elsewhere in New England 88,89 concluded that, in aquifers where elevated As concentrations were observed, As was ultimately derived from pyrite and other sulfide minerals, which, in contrast to silicate minerals, typically have significant concentrations of As.…”

Section: Origin and Chemical Forms Of Arsenic In The Sedimentsmentioning

confidence: 99%

The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer

Kent

2004

Geochem. Trans.

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We examined the chemical reactions influencing dissolved concentrations, speciation, and transport of naturally occurring arsenic ͑As͒ in a shallow, sand and gravel aquifer with distinct geochemical zones resulting from land disposal of dilute sewage effluent. The principal geochemical zones were: ͑1͒ the uncontaminated zone above the sewage plume ͓350 M dissolved oxygen ͑DO͒, pH 5.9͔; ͑2͒ the suboxic zone ͑5 M DO, pH 6.2, elevated concentrations of sewage-derived phosphate and nitrate͒; and ͑3͒ the anoxic zone ͓dissolved iron͑II͒ 100-300 M, pH 6.5-6.9, elevated concentrations of sewage-derived phosphate͔. Sediments are comprised of greater than 90% quartz but the surfaces of quartz and other mineral grains are coated with nanometer-size iron ͑Fe͒ and aluminum ͑Al͒ oxides and/or silicates, which control the adsorption properties of the sediments. Uncontaminated groundwater with added phosphate ͑620 M͒ was pumped into the uncontaminated zone while samples were collected 0.3 m above the injection point. Concentrations of As͑V͒ increased from below detection ͑0.005 M͒ to a maximum of 0.07 M during breakthrough of phosphate at the sampling port; As͑III͒ concentrations remained below detection. These results are consistent with the hypothesis that naturally occurring As͑V͒ adsorbed to constituents of the coatings on grain surfaces was desorbed by phosphate in the injected groundwater. Also consistent with this hypothesis, vertical profiles of groundwater chemistry measured prior to the tracer test showed that dissolved As͑V͒ concentrations increased along with dissolved phosphate from below detection in the uncontaminated zone to approximately 0.07 and 70 M, respectively, in the suboxic zone. Concentrations of As͑III͒ were below detection in both zones. The anoxic zone had approximately 0.07 M As͑V͒ but also had As͑III͒ concentrations of 0.07-0.14 M, suggesting that release of As bound to sediment grains occurred by desorption by phosphate, reductive dissolution of Fe oxides, and reduction of As͑V͒ to As͑III͒, which adsorbs only weakly to the Fe-oxide-depleted material in the coatings. Results of reductive extractions of the sediments suggest that As associated with the coatings was relatively uniformly distributed at approximately 1 nmol/g of sediment ͑equivalent to 0.075 ppm As͒ and comprised 20%-50% of the total As in the sediments, determined from oxidative extractions. Quartz sand aquifers provide high-quality drinking water but can become contaminated when naturally occurring arsenic bound to Fe and Al oxides or silicates on sediment surfaces is released by desorption and dissolution of Fe oxides in response to changing chemical conditions.

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Section: Origin and Chemical Forms Of Arsenic In The Sedimentsmentioning

confidence: 99%

The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer

Kent

2004

Geochem. Trans.

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“…The heavy metal cadmium (Cd) and the metalloid arsenic (As) are examples of elemental pollutants with a high affinity for thiols (Li et al, 2004). Arsenic pollution is widespread in the environment, and contamination of As in drinking water and food is a significant human health concern (Ayotte et al, 2003;Dhankher, 2005). The oxyanion arsenite (AsO 3 23 ) contains As in its trivalent form (As +3 or As III ) and is highly thiol reactive.…”

Section: Introductionmentioning

confidence: 99%

A -Glutamyl Cyclotransferase Protects Arabidopsis Plants from Heavy Metal Toxicity by Recycling Glutamate to Maintain Glutathione Homeostasis

et al. 2013

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Plants detoxify toxic metals through a GSH-dependent pathway. GSH homeostasis is maintained by the g-glutamyl cycle, which involves GSH synthesis and degradation and the recycling of component amino acids. The enzyme g-glutamyl cyclotransferase (GGCT) is involved in Glu recycling, but the gene(s) encoding GGCT has not been identified in plants. Here, we report that an Arabidopsis thaliana protein with a cation transport regulator-like domain, hereafter referred to as GGCT2;1, functions as g-glutamyl cyclotransferase. Heterologous expression of GGCT2;1 in Saccharomyces cerevisiae produced phenotypes that were consistent with decreased GSH content attributable to either GSH degradation or the diversion of g-glutamyl peptides to produce 5-oxoproline (5-OP). 5-OP levels were further increased by the addition of arsenite and GSH to the medium, indicating that GGCT2;1 participates in the cellular response to arsenic (As) via GSH degradation. Recombinant GGCT2;1 converted both GSH and g-glutamyl Ala to 5-OP in vitro. GGCT2;1 transcripts were upregulated in As-treated Arabidopsis, and ggct2;1 knockout mutants were more tolerant to As and cadmium than the wild type. Overexpression of GGCT2;1 in Arabidopsis resulted in the accumulation of 5-OP. Under As toxicity, the overexpression lines showed minimal changes in de novo Glu synthesis, while the ggct2;1 mutant increased nitrogen assimilation by severalfold, resulting in a very low As/N ratio in tissue. Thus, our results suggest that GGCT2;1 ensures sufficient GSH turnover during abiotic stress by recycling Glu.

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“…The actual valence states and chemical form, however, depend on the redox environments in the water systems including pH, oxidation-reduction potential, and the presence of complexing ions. 7,8 Toxic arsenic compounds have been detected in water supply wells in the United States 9 and abroad. The shallow groundwater, a major source of drinking water for many south and southeast Asian countries like Bangladesh, is contaminated with arsenic.…”

mentioning

confidence: 99%

Magnetic Graphene Nanoplatelet Composites toward Arsenic Removal

Zhu

Sadu

Wei

et al. 2012

ECS J. Solid State Sci. Technol.

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Magnetic graphene nanoplatelet composites (MGNCs) decorated with core-shell Fe-Fe 2 O 3 nanoparticles (NPs) have been synthesized using a facile one-pot thermal decomposition method. The graphene nanoplatelets (GNPs) decorated with uniformly dispersed NPs are observed to exhibit a strong magnetization and can be magnetically separated from the liquid mixture by a permanent magnet. These MGNCs demonstrate an effective and efficient adsorption of arsenic(III) in the polluted water due to the increased adsorption sites in the presence of magnetic NPs. The adsorption behavior is well fitted with both Langmuir and Freundlich models, which show a significantly higher adsorption capacity (11.34 mg/g) than the other adsorption values reported on the conventional iron oxide based adsorbents (∼1 mg/g). The results show a nearly complete As(III) removal within 1 ppb. © 2012 The Electrochemical Society. [DOI: 10.1149/2.010201jss] All rights reserved.Manuscript received March 8, 2012. Published July 17, 2012 Arsenic is known for its toxicity and carcinogenicity to human beings, 1-3 the contaminated water with arsenic is becoming a significantly increasing issue in drinking water throughout the world. Longterm exposure to arsenic can cause cancers of the bladder, lungs, skin, kidney, liver and prostate. 4 Arsenic contaminates include both natural and anthropogenic sources. Anthropogenic arsenic pollutants originate from mining and smelting of non-ferrous metals, burning of fossil fuels, usage of arsenic-containing pesticides in the agriculture 5 and arsenic-containing chemicals in the preservation of timber.6 Arsenic can exit in both inorganic and organic forms. In general, inorganic arsenic compounds are more toxic than organic arsenic compounds, and arsenite [As(III)] is considerably more mobile and toxic than arsenate [As(V)].7 Arsenate (i.e., HAsO 4 2− ) is the primary anion in the aerobic surface water and arsenite (i.e., H 3 AsO 3 or H 2 AsO 3 − ) is the primary species in the ground water. The actual valence states and chemical form, however, depend on the redox environments in the water systems including pH, oxidation-reduction potential, and the presence of complexing ions. There are several requirements that need to be met for arsenic removal such as safe and easy operation, high efficiency and low cost.7 Compared to the conventional water treatment techniques including oxidation/precipitation, 21 membrane/reverse osmosis, coagulation/coprecipitation, 22 and ion exchange, 7 adsorption has the following advantages. For example, it does not need a large volume or additional chemicals for treatment and it is easier to be deployed * Electrochemical Society Active Member.z E-mail: suying.wei@lamar.edu; zhanhu.guo@lamar.edu as a Point of Entry/Point of Use (POE/POU) arsenic removal process. Moreover, adsorption processes produce no sludge as met in the coagulation approach 7 and it does not need a strict control of pH values as met in the oxidation process.23 Adsorption can be dealt with low cost medium, low-tech operatio...

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Arsenic in Groundwater in Eastern New England: Occurrence, Controls, and Human Health Implications

Cited by 210 publications

References 14 publications

The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer

The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer

A -Glutamyl Cyclotransferase Protects Arabidopsis Plants from Heavy Metal Toxicity by Recycling Glutamate to Maintain Glutathione Homeostasis

Magnetic Graphene Nanoplatelet Composites toward Arsenic Removal

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