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- Bhattacharya, Prosun, et al.
(författare)
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Distribution and mobility of arsenic in the Rio Dulce alluvial aquifers in Santiago del Estero Province, Argentina
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 358:1-3, s. 97-120
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Tidskriftsartikel (refereegranskat)abstract
- Factors controlling arsenic (As) mobilization in the aquifers of the Rio Dulce alluvial cone were investigated. Groundwater analyses show severe As contamination (average concentration of 743 mu g/L) from geogenic sources, but spatial variability of As concentration is considerable. Sequential leaching of sediment samples from unsaturated zone using de-ionised water, bicarbonate, acetate, and oxalate extracted As to different extents. Sediment oxalate extraction showed that Al and Mn oxide and hydroxides are more abundant than Fe oxides and hydroxides, in spite of similar total Fe, Mn, and Al concentrations in the sediment. Speciation calculations performed for saturated zone samples indicated that Fe and Al oxides and hydroxides are stable in groundwater, suggesting that As adsorption processes may be to some extent controlled by the presence of Fe and Al mineral phases. Principal Component Analysis (PCA) showed that As is related to F, V, Mo, B, Si, most likely due to their common origin in volcanic ash. This suggests the volcanic ash as the probable source of groundwater As. Locally, elevated pH values linked to carbonate dissolution, cation exchange, and dissolution of silicates promote release of adsorbed As. Another factor contributing to the release of As locally may be the input of organic matter from excessive irrigation. The conceptual model of As release includes: i) As influx from dissolution of volcanic glass in volcanic ash, ii) adsorption of As on the surface of Fe and Al mineral phases in relatively low pH zones, and iii) high mobility of As in high pH zones. Future work should be focused on the determination of mineralogical forms of As in volcanic ash and on detailed investigation on factors controlling As mobility.
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| 2. |
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| 3. |
- Nriagu, J. O., et al.
(författare)
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Arsenic in soil and groundwater : an overview
- 2007. - 9
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Ingår i: Arsenic in Soil and Groundwater Environment. - Amsterdam, The Netherlands : Elsevier. - 9780444518200 ; , s. 3-60
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Contamination of the environment with arsenic (As) from both anthropogenic and natural sources has occurred in many parts of the world and is recognized as a global problem. Principal anthropogenic sources of As include base metal smelters, gold mines, power plants that burn As-rich coals or treated lumber, disposal sites for wastes from As-processing plants, as well as industrial and municipal dump sites. In many areas, the levels of As in the environment have become one of concern and epidemiological studies have documented various adverse health effects on local populations. Arsenic poisoning episodes from exposure to industrial sources have been reported all over the world; for instance, in Japan, where cases have been associated with pollution around As mines and pollution of groundwater around As-using industries and industrial waste burial sites. Other examples of contaminated environments with increased risk for As poisoning include agricultural lands treated with arsenical pesticides, urban areas, war zones defoliated or sprayed with As compounds, and the superfund sites in the United States and other countries. Although a lot of people get exposed, most often, however, it is not possible to associate the exposure to elevated As levels with adverse human health effects. Nevertheless, long-term cumulative exposure to As in these contaminated environments should be a matter of public health concern and scientific interest.
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| 4. |
- Bhattacharya, Prosun, et al.
(författare)
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Arsenic in the environment : Biology and Chemistry
- 2007
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 379:03-feb, s. 109-120
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Forskningsöversikt (refereegranskat)abstract
- Arsenic (As) distribution and toxicology in the environment is a serious issue, with millions of individuals worldwide being affected by As toxicosis. Sources of As contamination are both natural and anthropogenic and the scale of contamination ranges from local to regional. There are many areas of research that are being actively pursued to address the As contamination problem. These include new methods of screening for As in the field, determining the epidemiology of As in humans, and identifying the risk of As uptake in agriculture. Remediation of As-affected water supplies is important and research includes assessing natural remediation potential as well as phytoremediation. Another area of active research is on the microbially mediated biogeochemical interactions of As in the environment. In 2005, a conference was convened to bring together scientists involved in many of the different areas of As research. In this paper, we present a synthesis of the As issues in the light of long-standing research and with regards to the new findings presented at this conference. This contribution provides a backdrop to the issues raised at the conference together with an overview of contemporary and historical issues of As contamination and health impacts. Crown
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| 5. |
- Bhattacharya, Prosun, et al.
(författare)
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Groundwater characteristics in the shallow aquifers of Huhhot region in Inner Mongolia, PR China : Implications on the mobilisation of arsenic
- 2006
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Ingår i: Natural Arsenic in Groundwaters of Latin America. ; , s. 11-12
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Elevated arsenic (As) concentration ingroundwater is becoming a worldwide problem. In Huhhot Alluvial Basin (HAB) in Inner Mongolia, People’s Republic ofChina, a population of over a million isexposed to severe health risk due to theconsumption of groundwater with high Asconcentration. In some arsenic seriouslyaffected areas, As concentration reach 1491µg L-1, 149 times over WHO’s drinkingwater guideline value for As and exceed theChinese drinking water standard by a factorof 30 times. Due to the acute shortage ofsafe water supply and inefficient watermanagement system, people are compelledto drink groundwater with high As concentration. Long period ingestion of water withhigh As concentration have lead to chronicarsenic poisoning among the residents ofthe region. This present work deals with thehydrogeochemical characterisation of thegroundwater of the shallow alluvial aquifers and their implications on the chemistryand its relation to the mechanism of Asmobilization in the HAB.Groundwater samples were collected during October 2003, from 29 sites in the village of Tie Men Jing, located about 100 kmfrom Inner Mongolia’s capital Huhhot. ThepH, redox potential (Eh), temperature andelectrical conductivity were measured atsites while major ions, trace elements including As total and As (III) were analyzedin laboratories at the Royal Institute ofTechnology and Stockholm University inSweden. Groundwater is generally neutralto alkaline and the pH varies from 6.67 to8.7. The redox potential (Eh) lies between74 and 669 mV. The electrical conductivity(EC) range varies from 581 to 5200 µS cm-1. Temperature ranges from 9.1 to 13.5 °C.Depths of wells are from 4 m to 75 m.Groundwater is mostly of Na-Mg-HCO3-Cl-type and dominated by HCO3-and Cl-asthe predominant anions. The concentrationsof SO42-range between 0.3 and 172.8 mg L-1and there is a trend of decreasing sulfateconcentrations with increase in well depth.The levels of NO3-were lower than theWHO´s guideline value of 50 mg L-1in 27wells. These high NO3-concentrations could have been caused by anthropogeniccontamination due to the sanitation practices.The PO43-concentration ranges between 0.04to 2.6 mg L-1.Total As concentration ranged from belowdetect limit (5.2 µg L-1) to 141 µg L-1. In 28of the investigated wells, As levels exceededWHO’s guideline value 10 µg L-1and 17wells exceeded Chinese standard 50 µg L-1.Among the 42 groundwater samples of theshallow aquifers only three complied withthe WHO drinking water guideline value forAs. The dominant species in the groundwaterwas As (III). In the 29 wells of Tie MenJing, the concentration of Fe and Mn –exceeded the WHO’s guideline value by afactor of 10.The aquifers are composed of Quaternary(mainly Holocene) fluvial and lacustrinesediments. High As occurring in anaerobicgroundwater in low-lying areas is associatedwith high concenrations of dissolved Fe andMn. Improved water supply system, employment new water and energy resources,poverty fighting and expertise cooperationare recommended to solve Huhhot basinrural area’s drinking water problem.
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