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Arsenic: An Abundant Natural Poison
(Released March 2009)

 
  by Andreas Saldivar & Vicki Soto  

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  1. [Chemical treatment and decomposition technique of the chemical warfare agents containing arsenicals]

    Toshikazu Kaise and Kenji Kinoshita.

    Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, Vol. 129, No. 1, Jan 2009, pp. 45-51.

    The old Japanese army developed several chemical warfare agents on Ohkuno Island in Seto inland sea, Hiroshima Japan, during the period between 1919 and 1944. These chemical agents including yperite (mustard; irritating agent), lewisite (irritating agent), diphenylchloroarsine (DA; vomiting agent), diphenylcyanoarsine (DC; vomiting agent) and other poisonous gases were manufactured to be used in China. After World War II, the old Japanese army abandoned or dumped these agents into seas inside or outside of Japan and interior of China. Rather than being used for terrorism, these chemical warfare agents containing arsenicals may cause injury to some workers at the digging site of abandoned chemical weapons. Moreover, the leakage of chemical agents or an explosion of the bomb may result in environmental pollution, as a result, it is highly possible to cause serious health damage to the residents. There are still many abandoned or dumped warfare agents in Japan and China, therefore chemical agents containing arsenic are needed to be treated with alkaline for decomposition or to decompose with oxidizing agent. Presently, a large quantity of chemical agents and the contaminated soil are processed by combustion, and industrial waste is treated with sulfur compounds as the insoluble sulfur arsenic complex. This report describes the methods for the disposal of these organic arsenic agents that have been implemented until present and examines the future prospects.

  2. Arsenic and cardiovascular disease

    J. Christopher States, Sanjay Srivastava, Yu Chen and Aaron Barchowsky.

    Toxicological sciences : an official journal of the Society of Toxicology, Vol. 107, No. 2, Feb 2009, pp. 312-323.

    Chronic arsenic exposure is a worldwide health problem. Although arsenic-induced cancer has been widely studied, comparatively little attention has been paid to arsenic-induced vascular disease. Epidemiological studies have shown that chronic arsenic exposure is associated with increased morbidity and mortality from cardiovascular disease. In addition, studies suggest that susceptibility to arsenic-induced vascular disease may be modified by nutritional factors in addition to genetic factors. Recently, animal models for arsenic-induced atherosclerosis and liver sinusoidal endothelial cell dysfunction have been developed. Initial studies in these models show that arsenic exposure accelerates and exacerbates atherosclerosis in apolipoprotein E-knockout mice. Microarray studies of liver mRNA and micro-RNA abundance in mice exposed in utero suggest that a permanent state of stress is induced by the arsenic exposure. Furthermore, the livers of the arsenic-exposed mice have activated pathways involved in immune responses suggesting a pro-hyperinflammatory state. Arsenic exposure of mice after weaning shows a clear dose-response in the extent of disease exacerbation. In addition, increased inflammation in arterial wall is evident. In response to arsenic-stimulated oxidative signaling, liver sinusoidal endothelium differentiates into a continuous endothelium that limits nutrient exchange and waste elimination. Data suggest that nicotinamide adenine dinucleotide phosphate oxidase-derived superoxide or its derivatives are essential second messengers in the signaling pathway for arsenic-stimulated vessel remodeling. The recent findings provide future directions for research into the cardiovascular effects of arsenic exposure.

  3. Arsenic contamination of groundwater in the Terai region of Nepal: an overview of health concerns and treatment options

    D. Pokhrel, B. S. Bhandari and T. Viraraghavan.

    Environment international, Vol. 35, No. 1, Jan 2009, pp. 157-161.

    A review of published information on the arsenic contamination of groundwater in the Terai regions of Nepal showed that the source was mainly geogenic due to the dissolution of the arsenic-bearing minerals. Clinical observations of patients in the arsenic affected districts revealed chronic arsenic poisoning from drinking water. Half a million people inhabiting the region are believed to have been exposed to arsenic levels greater than 50 microg/L in their drinking water. Thirty-one percent of the population (3.5 million) in the region are estimated to have been exposed to arsenic levels between 10 and 50 microg/L. Iron assisted biosand filters currently distributed and in operation are a suitable alternative to mitigate the interim arsenic standard of 50 microg/L, as set by the Nepal Government. Arsenic biosand filters were also effective in removing bacteria and viruses from drinking water in laboratory and field tests. However, groundwater treatment targeting cluster communities in the Terai region is the sustainable way of mitigating the arsenic problem.

  4. Arsenic exposure during pregnancy and size at birth: a prospective cohort study in Bangladesh

    Anisur Rahman, Marie Vahter, Allan H. Smith, et al.

    American Journal of Epidemiology, Vol. 169, No. 3, Feb 1 2009, pp. 304-312.

    The authors evaluated the association of prenatal arsenic exposure with size at birth (birth weight, birth length, head and chest circumferences). This prospective cohort study, based on 1,578 mother-infant pairs, was conducted in Matlab, Bangladesh, in 2002-2003. Arsenic exposure was assessed by analysis of arsenic in urine collected at around gestational weeks 8 and 30. The association of arsenic exposure with size at birth was assessed by linear regression analyses. In analysis over the full range of exposure (6-978 microg/L), no dose-effect association was found with birth size. However, significant negative dose effects were found with birth weight and head and chest circumferences at a low level of arsenic exposure (<100 microg/L in urine). In this range of exposure, birth weight decreased by 1.68 (standard error (SE), 0.62) g for each 1-microg/L increase of arsenic in urine. For head and chest circumferences, the corresponding reductions were 0.05 (SE, 0.03) mm and 0.14 (SE, 0.03) mm per 1 microg/L, respectively. No further negative effects were shown at higher levels of arsenic exposure. The indicated negative effect on birth size at a low level of arsenic exposure warrants further investigation.

  5. Arsenic stability and mobilization in soil at an amenity grassland overlying chemical waste (St. Helens, UK)

    W. Hartley, N. M. Dickinson, R. Clemente, et al.

    Environmental Pollution, Vol. 157, No. 3, Mar 2009, pp. 847-856.

    A 6.6 ha grassland, established on a former chemical waste site adjacent to a residential area, contains arsenic (As) in surface soil at concentrations 200 times higher than UK Soil Guideline Values. The site is not recognized as statutory contaminated land, partly on the assumption that mobility of the metalloid presents a negligible threat to human health, groundwater and ecological receptors. Evidence for this is evaluated, based on studies of the effect of organic (green waste compost) and inorganic (iron oxides, lime and phosphate) amendments on As fractionation, mobility, plant uptake and earthworm communities. Arsenic mobility in soil was low but significantly related to dissolved organic matter and phosphate, with immobilization associated with iron oxides. Plant uptake was low and there was little apparent impact on earthworms. The existing vegetation cover reduces re-entrainment of dust-blown particulates and pathways of As exposure via this route. Minimizing risks to receptors requires avoidance of soil exposure, and no compost or phosphate application.

  6. Association between Morphological Changes of Nail and Nail Arsenic Level in Patients with Arsenicosis

    M. Shafiquzzaman, M. K. Jahan, M. M. Rahman, et al.

    Mymensingh medical journal : MMJ, Vol. 18, No. 1, Jan 2009, pp. 27-30.

    This case-control type of analytical study was conducted in the Department of Dermatology and Venereology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh to find out the association between morphological changes of nail and nail arsenic level in arsenicosis patients. Majority of arsenicosis patients were male (56.67%). The mean age of the cases was 43.07+/-13.73 years. Nail changes were found in 26.67% of cases, most were nail dystrophy (23.33%) and rest were Mee's line (3.34%). There was significant difference between cases with or without nail changes and nail arsenic level. But cases with or with out nail changes had a significant difference between duration of intake of arsenic contaminated water. There was no correlation between nail changes and nail arsenic level for nail dystrophy and Mee's line. The study result failed to establish association between the morphological changes of nail and nail arsenic level.

  7. Bhattacharya P., Mukherjee A. B., Bundschuh J., Zevenhoven R., and Loeppert R.H. (ed): Arsenic in Soil and Groundwater Environment. Biochemical Interactions, Health Effects and Remediation; Volume 9: Trace Metals in the Environment. Series edited by J. Nriagu

    Alina Kabata-Pendias.

    Environmental Geochemistry and Health, Vol. 31, No. 1, Feb 2009, pp. 159-160.

  8. The correlation of arsenic levels in drinking water with the biological samples of skin disorders

    Tasneem Gul Kazi, Muhammad Balal Arain, Jameel Ahmed Baig, et al.

    The Science of the total environment, Vol. 407, No. 3, Jan 15 2009, pp. 1019-1026.

    Arsenic (As) poisoning has become a worldwide public health concern. The skin is quite sensitive to As and skin lesions are the most common and earliest nonmalignant effects associated to chronic As exposure. In 2005-2007, a survey was carried out on surface and groundwater arsenic contamination and relationships between As exposure via the drinking water and related adverse health effects (melanosis and keratosis) on villagers resides on the banks of Manchar lake, southern part of Sindh, Pakistan. We screened the population from arsenic-affected villages, 61 to 73% population were identified patients suffering from chronic arsenic toxicity. The effects of As toxicity via drinking water were estimated by biological samples (scalp hair and blood) of adults (males and females), have or have not skin problem (n=187). The referent samples of both genders were also collected from the areas having low level of As (<10 microg/L) in drinking water (n=121). Arsenic concentration in drinking water and biological samples were analyzed using electrothermal atomic absorption spectrometry. The range of arsenic concentrations in lake surface water was 35.2-158 microg/L, which is 3-15 folds higher than World Health Organization [WHO, 2004. Guidelines for drinking-water quality third ed., WHO Geneva Switzerland.]. It was observed that As concentration in the scalp hair and blood samples were above the range of permissible values 0.034-0.319 microg As/g for hair and <0.5-4.2 microg/L for blood. The linear regressions showed good correlations between arsenic concentrations in water versus hair and blood samples of exposed skin diseased subjects (R2=0.852 and 0.718) as compared to non-diseased subjects (R2=0.573 and 0.351), respectively.

  9. Determination of arsenic levels in lake water, sediment, and foodstuff from selected area of Sindh, Pakistan: Estimation of daily dietary intake

    M. B. Arain, T. G. Kazi, J. A. Baig, et al.

    Food and Chemical Toxicology, Vol. 47, No. 1, Jan 2009, pp. 242-248.

    The aim of present study was to develop a database of arsenic (As) in lake water, ground water, sediment, soil, vegetables, grain crops and fish to evaluate the potential human health risks posed by higher level of As, in south east part of Sindh, Pakistan during 2005-2007. The total concentration of As in various samples under study was determined by electrothermal atomic absorption spectrophotometry (ETAAS). The reliability and accuracy of technique was checked by different certified reference materials. The concentration of As in lake and ground water samples exceeded the WHO guideline values. The concentration of As in lake sediment and agricultural soil samples ranged between 11.3-55.8 and 8.7-46.2mg/kg while acid soluble As (acetic acid 0.11mol/L) was observed in the range of 1.48-3.54 and 0.34-3.78mg/kg, respectively. It was observed that the leafy vegetables (spinach, coriander and peppermint) contain higher As levels (0.90-1.20mg/kg) as compared to ground vegetables (0.048-0.25) and grain crops (0.248-0.367mg/kg) on dried weight basis. The estimated daily intake of total As in the diet was 9.7-12.2 mu g/kg body weight/day.

  10. Determination of toxic trace elements in foodstuffs, soils and sediments of bangladesh using instrumental neutron activation analysis technique

    Shaikh Abdul Latif, D. Afroj, S. M. Hossain, et al.

    Bulletin of environmental contamination and toxicology, Vol. 82, No. 3, Mar 2009, pp. 384-388.

    The concentrations of arsenic (As), chromium (Cr) and iron (Fe) were determined in the foodstuffs, soils and sediments from various areas in Bangladesh and new data for these toxic trace elements were given. The arsenic pollution problems in the most of the areas of Bangladesh are of geological origin. The high level of As in foodstuffs, soils and sediments, except for tannery sediments is probably positively correlated to the Fe concentration. An excessive amount of chromium was found in the sediments from the tannery area of Bangladesh.

  11. Developmental mechanisms of arsenite toxicity in zebrafish (Danio rerio) embryos

    Dan Li, Cailing Lu, Ju Wang, et al.

    Aquatic Toxicology (Amsterdam, Netherlands), Vol. 91, No. 3, Feb 19 2009, pp. 229-237.

    Arsenic usually accumulates in soil, water and airborne particles, from which it is taken up by various organisms. Exposure to arsenic through food and drinking water is a major public health problem affecting some countries. At present there are limited laboratory data on the effects of arsenic exposure on early embryonic development and the mechanisms behind its toxicity. In this study, we used zebrafish as a model system to investigate the effects of arsenite on early development. Zebrafish embryos were exposed to a range of sodium arsenite concentrations (0-10.0mM) between 4 and 120h post-fertilization (hpf). Survival and early development of the embryos were not obviously influenced by arsenite concentrations below 0.5mM. However, embryos exposed to higher concentrations (0.5-10.0mM) displayed reduced survival and abnormal development including delayed hatching, retarded growth and changed morphology. Alterations in neural development included weak tactile responses to light (2.0-5.0mM, 30hpf), malformation of the spinal cord and disordered motor axon projections (2.0mM, 48hpf). Abnormal cardiac function was observed as bradycardia (0.5-2.0mM, 60hpf) and altered ventricular shape (2.0mM, 48hpf). Furthermore, altered cell proliferation (2.0mM, 24hpf) and apoptosis status (2.0mM, 24 and 48hpf), as well as abnormal genomic DNA methylation patterning (2.0mM, 24 and 48hpf) were detected in the arsenite-treated embryos. All of these indicate a possible relationship between arsenic exposure and developmental failure in early embryogenesis. Our studies suggest that the negative effects of arsenic on vertebrate embryogenesis are substantial.

  12. Dietary intake of methionine, cysteine, and protein and urinary arsenic excretion in Bangladesh

    Julia E. Heck, Jeri W. Nieves, Yu Chen, et al.

    Environmental health perspectives, Vol. 117, No. 1, Jan 2009, pp. 99-104.

    BACKGROUND: In Bangladesh, millions of people are exposed to arsenic in drinking water; arsenic is associated with increased risk of cancer. Once ingested, arsenic is metabolized via methylation and excreted in urine. Knowledge about nutritional factors affecting individual variation in methylation is limited. OBJECTIVES: The purpose of this study was to examine associations between intakes of protein, methionine, and cysteine total urinary arsenic in a large population-based sample. METHODS: The study subjects were 10,402 disease-free residents of Araihazar, Bangladesh, who participated in the Health Effects of Arsenic Longitudinal Study (HEALS). Food intakes were assessed using a validated food frequency questionnaire developed for the study population. Nutrient composition was determined by using the U.S. Department of Agriculture National Nutrient Database for Standard Reference. Generalized estimating equations were used to examine association between total urinary arsenic across quintiles of nutrient intakes while controlling for arsenic exposure from drinking water and other predictors of urinary arsenic. RESULTS: Greater intakes of protein, methionine, and cysteine were associated with 10-15% greater total urinary arsenic excretion, after controlling for total energy intake, body weight, sex, age, tobacco use, and intake of some other nutrients. CONCLUSIONS: Given previously reported risks between lower rates of arsenic excretion and increased rates of cancer, these findings support the role of nutrition in preventing arsenic-related disease.

  13. Effect of rice-cooking water to the daily arsenic intake in Bangladesh: results of field surveys and rice-cooking experiments

    K. Ohno, Y. Matsuo, T. Kimura, et al.

    Water science and technology : a journal of the International Association on Water Pollution Research, Vol. 59, No. 2, 2009, pp. 195-201.

    The effect of rice-cooking water to the daily arsenic intake of Bangladeshi people was investigated. At the first field survey, uncooked rice and cooked rice of 29 families were collected. Their arsenic concentrations were 0.22+/-0.11 and 0.26+/-0.15 mg/kg dry wt, respectively. In 15 families, arsenic concentration in rice increased after cooking. Good correlation (R(2)=0.89) was observed between arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. In the second survey, we collected one-day duplicated food of 18 families. As a result, we estimated that six of 18 families likely used the arsenic contaminated water for cooking rice even they drank less arsenic-contaminated water for drinking purpose. We also conducted rice-cooking experiments in the laboratory, changing arsenic concentration in rice-cooking water. Clear linear relationships were obtained between the arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. Factors that affect arsenic concentration in cooked rice are suggested as follows: (1) arsenic concentration in uncooked rice, (2) that in rice-cooking water, (3) difference in water content of rice before and after cooking, and (4) types of rice, especially, the difference between parboiled and non-parboiled rice.

  14. Effect of rice-cooking water to the daily arsenic intake in Bangladesh: results of field surveys and rice-cooking experiments

    K. Ohno, Y. Matsuo, T. Kimura, et al.

    Water.science and technology : a.journal of the International Association on Water.Pollution Research, Vol. 59, No. 2, 2009, pp. 195-201.

    The effect of rice-cooking water to the daily arsenic intake of Bangladeshi people was investigated. At the first field survey, uncooked rice and cooked rice of 29 families were collected. Their arsenic concentrations were 0.22+/-0.11 and 0.26+/-0.15 mg/kg dry wt, respectively. In 15 families, arsenic concentration in rice increased after cooking. Good correlation (R(2)=0.89) was observed between arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. In the second survey, we collected one-day duplicated food of 18 families. As a result, we estimated that six of 18 families likely used the arsenic contaminated water for cooking rice even they drank less arsenic-contaminated water for drinking purpose. We also conducted rice-cooking experiments in the laboratory, changing arsenic concentration in rice-cooking water. Clear linear relationships were obtained between the arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. Factors that affect arsenic concentration in cooked rice are suggested as follows: (1) arsenic concentration in uncooked rice, (2) that in rice-cooking water, (3) difference in water content of rice before and after cooking, and (4) types of rice, especially, the difference between parboiled and non-parboiled rice.

  15. Electrolyte conditioning-enhanced electrokinetic remediation of arsenic-contaminated mine tailing

    Kitae Baek, Do-Hyung Kim, Sung-Woo Park, Byung-Gon Ryu, Tserennyam Bajargal and Jung-Seok Yang.

    Journal of hazardous materials, Vol. 161, No. 1, Jan 15 2009, pp. 457-462.

    Feasibility of electrolyte conditioning with strong acidic or alkaline solution on electrokinetic remediation of arsenic-contaminated mine tailing was investigated in the laboratory. The mine tailing contained calcium oxide of more than 50%. At alkaline condition, arsenic was precipitated with calcium, and formed calcium arsenate which is very stable solid. Catholyte conditioning with strong acidic solution and anolyte conditioning with strong alkaline solution showed similar efficiency to remove arsenic. At 4mAcm(-2) of current density, the removal efficiency of arsenic was 62% after 28 days operation with catholyte conditioning with 0.1M nitric acid.

  16. Genes involved in arsenic transformation and resistance associated with different levels of arsenic-contaminated soils

    Lin Cai, Guanghui Liu, Christopher Rensing and Gejiao Wang.

    BMC microbiology, Vol. 9, 2009, pp. 4.

    BACKGROUND: Arsenic is known as a toxic metalloid, which primarily exists in inorganic form [As(III) and As(V)] and can be transformed by microbial redox processes in the natural environment. As(III) is much more toxic and mobile than As(V), hence microbial arsenic redox transformation has a major impact on arsenic toxicity and mobility which can greatly influence the human health. Our main purpose was to investigate the distribution and diversity of microbial arsenite-resistant species in three different arsenic-contaminated soils, and further study the As(III) resistance levels and related functional genes of these species. RESULTS: A total of 58 arsenite-resistant bacteria were identified from soils with three different arsenic-contaminated levels. Highly arsenite-resistant bacteria (MIC > 20 mM) were only isolated from the highly arsenic-contaminated site and belonged to Acinetobacter, Agrobacterium, Arthrobacter, Comamonas, Rhodococcus, Stenotrophomonas and Pseudomonas. Five arsenite-oxidizing bacteria that belonged to Achromobacter, Agrobacterium and Pseudomonas were identified and displayed a higher average arsenite resistance level than the non-arsenite oxidizers. 5 aoxB genes encoding arsenite oxidase and 51 arsenite transporter genes [18 arsB, 12 ACR3(1) and 21 ACR3(2)] were successfully amplified from these strains using PCR with degenerate primers. The aoxB genes were specific for the arsenite-oxidizing bacteria. Strains containing both an arsenite oxidase gene (aoxB) and an arsenite transporter gene (ACR3 or arsB) displayed a higher average arsenite resistance level than those possessing an arsenite transporter gene only. Horizontal transfer of ACR3(2) and arsB appeared to have occurred in strains that were primarily isolated from the highly arsenic-contaminated soil. CONCLUSION: Soils with long-term arsenic contamination may result in the evolution of highly diverse arsenite-resistant bacteria and such diversity was probably caused in part by horizontal gene transfer events. Bacteria capable of both arsenite oxidation and arsenite efflux mechanisms had an elevated arsenite resistance level.

  17. Influence of groundwater recharge and well characteristics on dissolved arsenic concentrations in southeastern Michigan groundwater

    Jaymie R. Meliker, Melissa J. Slotnick, Gillian A. Avruskin, Sheridan K. Haack and Jerome O. Nriagu.

    Environmental Geochemistry and Health, Vol. 31, No. 1, Feb 2009, pp. 147-157.

    Arsenic concentrations exceeding 10 microg/l, the United States maximum contaminant level and the World Health Organization guideline value, are frequently reported in groundwater from bedrock and unconsolidated aquifers of southeastern Michigan. Although arsenic-bearing minerals (including arsenian pyrite and oxide/hydroxide phases) have been identified in Marshall Sandstone bedrock of the Mississippian aquifer system and in tills of the unconsolidated aquifer system, mechanisms responsible for arsenic mobilization and subsequent transport in groundwater are equivocal. Recent evidence has begun to suggest that groundwater recharge and characteristics of well construction may affect arsenic mobilization and transport. Therefore, we investigated the relationship between dissolved arsenic concentrations, reported groundwater recharge rates, well construction characteristics, and geology in unconsolidated and bedrock aquifers. Results of multiple linear regression analyses indicate that arsenic contamination is more prevalent in bedrock wells that are cased in proximity to the bedrock-unconsolidated interface; no other factors were associated with arsenic contamination in water drawn from bedrock or unconsolidated aquifers. Conditions appropriate for arsenic mobilization may be found along the bedrock-unconsolidated interface, including changes in reduction/oxidation potential and enhanced biogeochemical activity because of differences between geologic strata. These results are valuable for understanding arsenic mobilization and guiding well construction practices in southeastern Michigan, and may also provide insights for other regions faced with groundwater arsenic contamination.

  18. Levels of urinary total and speciated arsenic in the US population: National Health and Nutrition Examination Survey 2003-2004

    Kathleen L. Caldwell, Robert L. Jones, Carl P. Verdon, Jeffery M. Jarrett, Samuel P. Caudill and John D. Osterloh.

    Journal of exposure science & environmental epidemiology, Vol. 19, No. 1, Jan 2009, pp. 59-68.

    OBJECTIVE: To provide levels of total and speciated urinary arsenic in a representative sample of the US population. METHODS: For the first time, total arsenic and seven inorganic and organic arsenic species were measured in the urine of participants (n=2557) for the 2003-2004 National Health and Nutrition Examination Survey (NHANES). Data were compiled as geometric means and selected percentiles of urinary arsenic concentrations (microg/l) and creatinine-corrected urinary arsenic (microg/g creatinine) for total arsenic, dimethylarsinic acid, arsenobetaine, and a sum of the inorganic related species.Results:Arsenic acid, arsenous acid, arsenocholine, and trimethylarsine oxide were detected in 7.6%, 4.6%, 1.8%, and 0.3% of the participants, respectively (the limits of detection of 0.6-1.2 microg/l). Monomethylarsonic acid was detected in 35% of the overall population. For all participants aged > or =6 years, dimethylarsinic acid (geometric mean of 3.71 microg/l) and arsenobetaine (geometric mean of 1.55 microg/l) had the greatest contribution to the total urinary arsenic levels. A relatively greater percentage contribution from arsenobetaine is seen at higher total urinary arsenic levels and from dimethylarsinic acid at lower total urinary arsenic levels. For all participants aged > or =6 years, the 95th percentiles for total urinary arsenic and the sum of inorganic-related arsenic (arsenic acid, arsenous acid, dimethylarsinic acid, and monomethylarsonic acid) were 65.4 and 18.9 microg/l, respectively. For total arsenic and dimethylarsinic acid, covariate-adjusted geometric means demonstrated several slight differences due to age, gender, and race/ethnicity.Conclusions:The data reflect relative background contributions of inorganic and seafood-related arsenic exposures in the US population. Arsenobetaine and dimethylarsinic acid are the major arsenic species present with arsenobetaine, accounting for a greater proportion of total arsenic as total arsenic levels increase.

  19. Mechanism of arsenate mobilization from goethite by aliphatic carboxylic acid

    Rong Shi, Yongfeng Jia, Chengzhi Wang and Shuhua Yao.

    Journal of hazardous materials, Vol. 163, No. 2-3, Apr 30 2009, pp. 1129-1133.

    Arsenic is highly toxic and therefore represents a potential threat to the environment and human health. The mobility and fixation of arsenic in natural environment is significantly affected by co-occurring dissolved natural organic acids, which are widely present in soils and sediments due to the decomposition of natural organic matters and the metabolism of plant roots and microorganisms. It was reported recently that at lower pH, citrate decreased arsenate adsorption on metal oxides as the result of competitive adsorption. This study examined the relationship between citrate-promoted goethite dissolution and citrate-suppressed arsenate adsorption in the equilibrated goethite-arsenate-citrate systems with different contact orders. The results indicated that there is obvious correlation between the suppression of arsenate adsorption and dissolution of goethite. Arsenate adsorption and goethite dissolution in the presence of citrate (1.0mM), oxalate (1.5mM) and acetate (3.0mM) were compared. The results showed that arsenate adsorption was most significantly inhibited by citrate among the three organic acids. Although oxalate dissolved goethite more significantly, it inhibited arsenate adsorption much less than citrate. Hence it is proposed that the competition for binding sites rather than citrate-promoted goethite dissolution played a key role in the reduction of arsenate adsorption by citrate at lower pH.

  20. Performance of a small-scale RO desalinator for arsenic removal

    T. Geucke, S. A. Deowan, J. Hoinkis and Ch Patzold.

    Desalination, Vol. 239, No. 1-3, Apr 2009, pp. 198-206.

    Arsenic poisoning in drinking water is a health issue in many Asian countries including Bangladesh, India, China and Vietnam. In areas where the drinking water supply contains unsafe levels of arsenic, technologies to remove arsenic are of prime importance. Many technologies have been developed for the removal of arsenic. Among those reverse osmosis (RO) and nanofiltration (NF) are very promising techniques because they have the advantage of removing dissolved arsenic along with other dissolved and particulate compounds. So far, however, this kind of membrane filtration has needed bulky and sophisticated units, which are not suitable for application in the rural areas of developing and newly industrializing countries. Therefore the purpose of this work was to test a small-scale, commercially available marine RO desalinator with three different membrane modules on arsenic removal. The experiments were conducted with arsenic-spiked local tap water, using As(III) and As(V) up to feed concentrations of 2400 mu g/L. The As(V) rejection was generally much better than the retention of As(III). With two of the tested membranes As(V) rejection was so high, that the permeate water quality complied with the WHO recommended maximum contaminant level (MCL) of 10 mu g/L even at a feed concentration of 2400 mg/L. In the case of As(III) only feed concentrations below 350 mu g/L resulted in permeate concentration lower than the MCL. The experiments should provide a basis for field tests on the ground in Bangladesh using natural arsenic contaminated groundwater. These field tests are currently running.

  21. Phytoremediation trials on metal- and arsenic-contaminated pyrite wastes (Torviscosa, Italy)

    T. Vamerali, M. Bandiera, L. Coletto, F. Zanetti, N. M. Dickinson and G. Mosca.

    Environmental Pollution, Vol. 157, No. 3, Mar 2009, pp. 887-894.

    At a site in Udine, Italy, a 0.7m layer of As, Co, Cu, Pb and Zn contaminated wastes derived from mineral roasting for sulphur extraction had been covered with an unpolluted 0.15m layer of gravelly soil. This study investigates whether woody biomass phytoremediation is a realistic management option. Comparing ploughing and subsoiling (0.35m depth), the growth of Populus and Salix and trace element uptake were investigated in both pot and field trials. Species differences were marginal and species selection was not critical. Impaired above-ground productivity and low translocation of trace elements showed that bioavailable contaminant stripping was not feasible. The most significant finding was of coarse and fine roots proliferation in surface layers that provided a significant sink for trace elements. We conclude that phytostabilisation and effective immobilisation of metals and As could be achieved at the site by soil amelioration combined with woody species establishment. Confidence to achieve a long-term and sustainable remediation requires a more complete quantification of root dynamics and a better understanding of rhizosphere processes.

  22. Relationship of urinary arsenic metabolites to intake estimates in residents of the Red River Delta, Vietnam

    Tetsuro Agusa, Takashi Kunito, Tu Binh Minh, et al.

    Environmental pollution (Barking, Essex : 1987), Vol. 157, No. 2, Feb 2009, pp. 396-403.

    This study investigated the status of arsenic (As) exposure from groundwater and rice, and its methylation capacity in residents from the Red River Delta, Vietnam. Arsenic levels in groundwater ranged from <1.8 to 486 microg/L. Remarkably, 86% of groundwater samples exceeded WHO drinking water guideline of 10 microg/L. Also, estimated inorganic As intake from groundwater and rice were over Provisional Tolerable Weekly Intake (15 microg/week/kg body wt.) by FAO/WHO for 92% of the residents examined. Inorganic As and its metabolite (monomethylarsonic acid and dimethylarsinic acid) concentrations in human urine were positively correlated with estimated inorganic As intake. These results suggest that residents in these areas are exposed to As through consumption of groundwater and rice, and potential health risk of As is of great concern for these people. Urinary concentration ratios of dimethylarsinic acid to monomethylarsonic acid in children were higher than those in adults, especially among men, indicating greater As methylation capacity in children.

  23. Simple and selective determination of arsenite and arsenate by electrospray ionization mass spectrometry

    Kayoko Minakata, Masako Suzuki and Osamu Suzuki.

    Analytica Chimica Acta, Vol. 631, No. 1, Jan 5 2009, pp. 87-90.

    Arsenic pollution of public water supplies has been reported in various regions of the world. Recently, some cancer patients are treated with arsenite (As(III)); most Japanese people consume seafoods containing large amounts of negligibly toxic arsenic compounds. Some of these arsenic species are metabolized, but some remain intact. For the determination of toxic As(III), a simple, rapid and sensitive method has been developed using electrospray ionization mass spectrometry (ESI-MS). As(III) was reacted with a chelating agent, pyrrolidinedithiocarbamate (PDC, C(4)H(8)NCSS(-)) and tripyrrolidinedithiocarbamate-arsine, As(PDC)(3), extracted with methyl isobutyl ketone (MIBK). A 1 microL aliquot of MIBK layer was directly injected into ESI-MS instrument without chromatographic separation, and was detected within 1 min. Arsenate (As(V)) was reduced to As(III) with thiosulfate, and then the total inorganic As was quantified as As(III). This method was validated for the analysis of urine samples. The limit of detection of As was 0.22 microg L(-1) using 10 microL of sample solution, and it is far below the permissible limit of As in drinking water, 10 microg L(-1), recommended by the WHO. Results were obtained in <10 min with a linear calibration range of 1-100 microg L(-1). Several organic arsenic compounds in urine did not interfere with As(III) detection, and the inorganic As in the reference materials SRM 2670a and 1643e were quantified after the reduction of As(V) to As(III).

  24. Slurry bioreactor modeling using a dissimilatory arsenate-reducing bacterium for remediation of arsenic-contaminated soil

    Satoshi Soda, Masaya Kanzaki, Shigeki Yamamuara, Masami Kashiwa, Masanori Fujita and Michihiko Ike.

    Journal of bioscience and bioengineering, Vol. 107, No. 2, Feb 2009, pp. 130-137.

    A slurry bioreactor using a dissimilatory arsenate (As(V))-reducing bacterium is proposed for remediation of arsenic-contaminated soils. Bacterial As(V) reduction can cause arsenic extraction from the solid to the liquid phase because arsenite, As(III), is much less adsorptive than As(V). A mathematical model was developed incorporating the reversible sorption process of arsenic as well as bacterial growth and decay via As(V) reduction. A linear isotherm equation expressed the sorption process. The model included Haldane kinetics with high As(V) concentrations and cell inactivation by toxicity due to As(III). Extraction experiments used synthetic contaminated soils (forest soil, Soil SF, 1100 mg kg(-1); paddy soil, Soil SP, 1100 mg kg(-1)) and actual contaminated soils (Soil AH 2200 mg kg(-1) and Soil AL, 220 mg kg(-1)) at 5% w/v slurry concentration. Simulation results matched the observed changes of arsenic concentrations in the liquid phase. The respective extraction efficiencies of arsenic were 63%, 41%, 20%, and 55% for SF, SP, AH, and AL soils. Sensitivity analyses showed that the rate-limiting step was the desorption rate of As(V) from the solid to the liquid phase, rather than the As(V)-reducing rate. The proposed model provides a useful framework for understanding and predicting the extraction of arsenic from soil.

  25. Speciation and enrichment of arsenic in strongly reducing shallow aquifers at western Hetao Plain, northern China

    Yamin Deng, Yanxin Wang, Teng Ma and Yiqun Gan.

    Environmental Geology, Vol. 56, No. 7, Feb 2009, pp. 1467-1477.

    High arsenic (As) groundwater is widely distributed in northwestern Hetao Plain, an arid region with sluggish groundwater flow. Observed As concentration in groundwater from wells ranges from 76 to 1,093 ?g/l. Most water samples have high total dissolved solids, with Cl and HCOv(3) as the dominant anions and Na as the dominant cation. The major hydrochemical types of most saline groundwaters are Na-Mg-Cl-HCOv(3) and Na-Mg-Cl. By contrast, fresh groundwaters generally belong to the Na-Mg-HCOv(3) type. High concentrations of arsenic in shallow aquifers are associated with strongly reducing conditions, as evidenced by high concentrations of dissolved organic carbon, ammonium, as well as dissolved sulfide and Fe, dominance of arsenite, relatively low concentrations of nitrate and sulfate, and occasionally high content of dissolved methane (CHv(4)). High As groundwaters from different places at Hetao Plain experienced different redox processes. Fluoride is also present in high As groundwater, ranging between 0.40 and 3.36 mg/l. Although fluorosis poses an additional health problem in the region, it does not correlate well with As in spatial distribution. Geochemical analysis indicates that evapotranspiration is an important process controlling the enrichment of Na and Cl, as well as trace elements such as As, B, and Br in groundwater.

  26. Acute toxicity and bioaccumulation of arsenic in freshwater clam Corbicula fluminea

    Chung-Min Liao, Sheng-Feng Jau, Wei-Yu Chen, et al.

    Environmental toxicology, Vol. 23, No. 6, Dec 2008, pp. 702-711.

    Arsenic is a potent human carcinogen of skin, lung, and urinary bladder. Freshwater clam Corbicula fluminea is a commercially important native species in Taiwan. C. fluminea is also a suitable biomonitoring test organism. Little is known, however, about the actual effects of arsenic on C. fluminea. The objectives of this study were to provide information on the acute toxicity and bioaccumulation kinetics of arsenic in C. fluminea. We carried out a 14-day exposure experiment to obtain bioaccumulation parameters. Uptake was very rapid when C. fluminea was first exposed and then slightly decayed during the uptake phase of the experiment and an uptake rate constant of 1.718 +/- 6.70 (mean +/- SE) mL g(-1) d(-1) was estimated. The elimination of arsenic from C. fluminea obeyed first-order depuration kinetics (r(2) = 0.85, p < 0.05) with a calculated half-life of 6.80 days. The derived bioaccumulation factor of 16.84 suggests that arsenic has a high potential for bioaccumulation in C. fluminea. This had important implications for dietary exposure of arsenic to humans who eat contaminated clams, because the soft tissue usually constitutes the majority of tissue consumed. The 96-h LC50 value was estimated to be 20.74 (95% CI: 11.74-30.79) mg L(-1) obtained from a 7-day acute toxicity bioassay. We also kinetically linked an acute toxicity model and a Hill sigmoid model to reconstruct an internal effect concentration based dose-response profile to assess the effect of soft tissue arsenic burden on the C. fluminea mortality. This result could be used to support the establishment of an ecological risk assessment to prevent possible ecosystem and human health consequences. (2008 Wiley Periodicals, Inc.)

  27. Acute toxicity and bioaccumulation of arsenic in freshwater clam Corbicula fluminea

    Chung-Min Liao, Sheng-Feng Jau, Wei-Yu Chen, et al.

    Environmental toxicology, 2008 Dec, Vol. 23, No. 6, 2008, pp. 702-711.

    Arsenic is a potent human carcinogen of skin, lung, and urinary bladder. Freshwater clam Corbicula fluminea is a commercially important native species in Taiwan. C. fluminea is also a suitable biomonitoring test organism. Little is known, however, about the actual effects of arsenic on C. fluminea. The objectives of this study were to provide information on the acute toxicity and bioaccumulation kinetics of arsenic in C. fluminea. We carried out a 14-day exposure experiment to obtain bioaccumulation parameters. Uptake was very rapid when C. fluminea was first exposed and then slightly decayed during the uptake phase of the experiment and an uptake rate constant of 1.718 +/- 6.70 (mean +/- SE) mL g(-1) d(-1) was estimated. The elimination of arsenic from C. fluminea obeyed first-order depuration kinetics (r(2) = 0.85, p < 0.05) with a calculated half-life of 6.80 days. The derived bioaccumulation factor of 16.84 suggests that arsenic has a high potential for bioaccumulation in C. fluminea. This had important implications for dietary exposure of arsenic to humans who eat contaminated clams, because the soft tissue usually constitutes the majority of tissue consumed. The 96-h LC50 value was estimated to be 20.74 (95% CI: 11.74-30.79) mg L(-1) obtained from a 7-day acute toxicity bioassay. We also kinetically linked an acute toxicity model and a Hill sigmoid model to reconstruct an internal effect concentration based dose-response profile to assess the effect of soft tissue arsenic burden on the C. fluminea mortality. This result could be used to support the establishment of an ecological risk assessment to prevent possible ecosystem and human health consequences. (2008 Wiley Periodicals, Inc.)

  28. Application of arsenic baselines in the assessment of soil contamination in Finland

    Jaana Jarva, Timo Tarvainen and Jussi Reinikainen.

    Environmental Geochemistry and Health, Vol. 30, No. 6, Dec 2008, pp. 613-621.

    In Finland, a new Government Decree on the Assessment of Soil Contamination and Remediation Needs (214/2007) came into force on 1 June 2007. According to the Decree, natural baseline concentration levels should be taken into account when assessing potential soil contamination and the need for remediation. This applies particularly in the case of toxic metallic elements, since baseline concentrations may naturally be rather high. The new decree prescribes soil screening values for 52 substances or groups of substances. The natural baseline concentrations have been taken into account in the definition of the screening values for inorganic pollutants. The Geological Survey of Finland (GTK) carried out a nation-wide geochemical mapping of till on a reconnaissance scale in 1983 and on a regional scale during 1984-1992. These surveys have provided information on natural elemental distribution in subsoils of the glacial till. However, some important trace elements in regional mapping such as arsenic are missing from the analysis, and subsoil samples do not reflect the diffuse anthropogenic input. Thus, GTK has continued the survey work by determining geochemical baselines around suburban areas. Samples have been taken from humus, topsoil and subsoil layers, and the soil parent material has covered sandy soils, glacial tills and fine-grained sediments. According to the studies, a regional difference in the levels of arsenic and some other trace elements can be clearly seen, especially in minerogenic soils. The results illustrate the importance of information on regional baseline concentrations while assessing potential soil contamination.

  29. Arsenic in hair and nails of individuals exposed to arsenic-rich groundwaters in Kandal province, Cambodia

    A. G. Gault, HelenA L. Rowland, J. M. Charnock, et al.

    Science of the Total Environment, Vol. 393, No. 1, 1 Apr 2008, pp. 168-176.

    The health implications of the consumption of high arsenic groundwater in Bangladesh and West Bengal are well-documented, however, little is known about the level of arsenic exposure elsewhere in Southeast Asia, where widespread exploitation of groundwater resources is less well established. We measured the arsenic concentrations of nail and hair samples collected from residents of Kandal province, Cambodia, an area recently identified to host arsenic-rich groundwaters, in order to evaluate the extent of arsenic exposure. Nail and hair arsenic concentrations ranged from 0.20 to 6.50 mu g g super(-) super(1) (n=70) and 0.10 to 7.95 mu g g super(-) super(1) (n=40), respectively, in many cases exceeding typical baseline levels. The arsenic content of the groundwater used for drinking water purposes (0.21-943 mu g L super(-) super(1) (n=31)) was positively correlated with both nail (r=0.74, p<0.0001) and hair (r=0.86, p<0.0001) arsenic concentrations. In addition, the nail and hair samples collected from inhabitants using groundwater that exceeded the Cambodian drinking water legal limit of 50 mu g L super(-) super(1) arsenic contained significantly more arsenic than those of individuals using groundwater containing <50 mu g L super(-) super(1) arsenic. X-ray absorption near edge structure (XANES) spectroscopy suggested that sulfur-coordinated arsenic was the dominant species in the bulk of the samples analysed, with additional varying degrees of As(III)-O character. Tentative linear least squares fitting of the XANES data pointed towards differences in the pattern of arsenic speciation between the nail and hair samples analysed, however, mismatches in sample and standard absorption peak intensity prevented us from unambiguously determining the arsenic species distribution. The good correlation with the groundwater arsenic concentration, allied with the relative ease of sampling such tissues, indicate that the arsenic content of hair and nail samples may be used as an effective biomarker of arsenic intake in this relatively recently exposed population.

  30. Arsenic trioxide and low-dose cytarabine in older patients with untreated acute myeloid leukemia, excluding acute promyelocytic leukemia

    Gail J. Roboz, Ellen K. Ritchie, Tania Curcio, et al.

    Cancer, Vol. 113, No. 9, Nov 1 2008, pp. 2504-2511.

    BACKGROUND: Acute myeloid leukemia (AML) carries a dismal prognosis in older patients. In this study, the authors evaluated the safety and efficacy of arsenic trioxide combined with low-dose cytarabine in untreated patients aged >or=60 years with AML. METHODS: In a phase 1/2 design, arsenic trioxide was administered intravenously at a dose of 0.25 mg/kg on Days 1 through 5 and on Days 8 through 12, and low-dose cytarabine was given subcutaneously twice daily on Days 1 through 14 in escalating doses to a target of 10 mg/m(2) per dose. Of 64 patients who had pathologically confirmed AML, excluding patients with acute promyelocytic leukemia and using World Health Organization criteria, the median age was 71 years, 10 patients (16%) had treatment-related AML, 40 patients (63%) had an antecedent myelodysplastic syndrome or myeloproliferative disorder, and 35 patients (55%) had unfavorable cytogenetics. Thirty-four patients (53%) had an Eastern Cooperative Oncology Group performance status of 2 or 3. RESULTS: Complete remission was achieved in 21 of 61 patients (34%), including 15 of 50 patients (30%) who had secondary or treatment-related AML, 10 of 33 patients (30%) who had unfavorable cytogenetics, and 6 of 34 patients (18%) who had a poor baseline performance status. The mortality rate within the first 4 weeks was 8%. Neutropenic fever was observed in >80% of patients, and 41% of patients had bacteremia. Nonhematologic toxicity generally was mild and reversible and included fatigue, nausea, diarrhea, rash, peripheral edema, and elevated transaminases. There were no clinically significant cardiac arrhythmias. CONCLUSIONS: The addition of arsenic trioxide to low-dose cytarabine appeared to improve responses in elderly patients who had AML compared with either agent alone, and a randomized trial of the combination versus single-agent low-dose cytarabine is ongoing.

  31. Arsenicosis in Cambodia: Case studies and policy response

    M. L. Sampson, B. Bostick, Hannah Chiew, J. M. Hagan and A. Shantz.

    Applied Geochemistry, Vol. 23, No. 11, Nov 2008, pp. 2976-2985.

    Naturally occurring As found in groundwaters has been identified to be a problem in at least 10 provinces of Cambodia with Kandal being one of the most heavily impacted. Estimates, using groundwater quality and population data for Kandal Province of Cambodia, suggest that over 100,000 people are at high risk of chronic As exposure. Levels in some areas approach 3500 mu g/L, against the Cambodian Standard of 50 mu g/L. Considerable work remains to adequately characterize the extent of As hazard and its possible health effects in Cambodia and the region. It is likely that additional populations will develop health problems attributed to As, of particular concern is arsenicosis. The symptoms of arsenicosis have been generally assumed to develop after 8-10 years of consumption of water with elevated As levels, however, new cases discovered in Cambodia have been identified with exposure times as short as 3 years. The rapid onset of arsenicosis may be attributed to contributing risk factors related to socioeconomic status, including malnutrition. It is thus imperative to develop strategies to rapidly identify possible regions of enrichment, to minimize exposure to As-rich waters, and to educate affected populations. To date the response to the As hazard has been led by the Ministry of Rural Development in cooperation with international organizations and NGOs, to identify at risk areas, and educate communities of the risk of As-rich water. However better coordination between government bodies, NGOs and donor agencies active in the field of water supply and treatment is essential to minimize future As exposure.

  32. Arsenicosis in Cambodia; case studies and policy response; Arsenic in ground waters of Southeast Asia; with emphasis on Cambodia and Vietnam

    M. L. Sampson, B. Bostick, H. Chiew, J. M. Hagan and A. Shantz.

    Applied Geochemistry, Vol. 23, No. 11, Nov 2008, pp. 2977-2986.

    Naturally occurring As found in groundwaters has been identified to be a problem in at least 10 provinces of Cambodia with Kandal being one of the most heavily impacted. Estimates, using groundwater quality and population data for Kandal Province of Cambodia, suggest that over 100,000 people are at high risk of chronic As exposure. Levels in some areas approach 3500mu g/L, against the Cambodian Standard of 50mu g/L. Considerable work remains to adequately characterize the extent of As hazard and its possible health effects in Cambodia and the region. It is likely that additional populations will develop health problems attributed to As, of particular concern is arsenicosis. The symptoms of arsenicosis have been generally assumed to develop after 8-10years of consumption of water with elevated As levels, however, new cases discovered in Cambodia have been identified with exposure times as short as 3years. The rapid onset of arsenicosis may be attributed to contributing risk factors related to socioeconomic status, including malnutrition. It is thus imperative to develop strategies to rapidly identify possible regions of enrichment, to minimize exposure to As-rich waters, and to educate affected populations. To date the response to the As hazard has been led by the Ministry of Rural Development in cooperation with international organizations and NGOs, to identify at risk areas, and educate communities of the risk of As-rich water. However better coordination between government bodies, NGOs and donor agencies active in the field of water supply and treatment is essential to minimize future As exposure.

  33. Bangladesh and Vietnam: different groundwater compositions require different approaches to arsenic mitigation

    Stephan J. Hug, Olivier X. Leupin and Michael Berg.

    Environmental science & technology, Vol. 42, No. 17, Sep 1 2008, pp. 6318-6323.

  34. Collateral benefits and hidden hazards of soil arsenic during abatement assessment of residential lead hazards

    M. P. Elless, B. W. Ferguson, C. A. Bray, S. Patch, H. Mielke and M. J. Blaylock.

    Environmental pollution (Barking, Essex : 1987), Vol. 156, No. 1, Nov 2008, pp. 20-28.

    Abatement of soil-lead hazards may also reduce human exposure to other soil toxins, thereby achieving significant collateral benefits that are not accounted for today. This proposition was tested with the specific case of soil-arsenic, where 1726 residential soil samples were collected and analyzed for lead and arsenic. The study found that these two toxins coexisted in most samples, but their concentrations were weakly correlated, reflecting the differing sources for each toxin. Collateral benefits of 9% would be achieved during abatement of the lead-contaminated soils having elevated arsenic concentrations. However, a hidden hazard of 16% was observed by overlooking elevated arsenic concentrations in soils having lead concentrations not requiring abatement. This study recommends that soil samples collected under HUD programs should be collected from areas of lead and arsenic deposition and tested for arsenic as well as lead, and that soil abatement decisions consider soil-arsenic as well as soil-lead guidelines.

  35. A comparison of two techniques for calculating ground water arsenic-related lung, bladder and liver cancer disease burden using data from Chakdha block, West Bengal; Arsenic in ground waters of Southeast Asia; with emphasis on Cambodia and Vietnam

    D. Mondal, G. C. D. Adamson, R. Nickson and D. A. Polya.

    Applied Geochemistry, Vol. 23, No. 11, Nov 2008, pp. 2999-3009.

    Calculation of excess disease burden for As exposed populations is becoming increasingly important to enable quantitative estimation of the impacts of various As mitigation options. There are several methods by which such calculations may be carried out. In this study, two methods, recently applied to estimating groundwater As-related health risks in southern Asia, to estimate disease burden arising from lung, bladder and liver cancer from As exposure for an As-effected area of West Bengal have been compared. Both utilized calculated distributions of exposure of the studied population to As from groundwater. Method (I) then entailed calculating disease burden by combining published background rates for death and disability adjusted life years (DALYs) and standard mortality ratios (SMRs) for excess health impacts related to As exposure, whilst for Method (II), disease burden from As exposure was estimated using the basic DALY formula, combined with incidence rates based on the NRC multistage Weibull model. Dose-response data for both methods were based on studies in Taiwan. When the same dose-response model was used for both methods, the two methods were broadly comparable, agreeing to within a factor of 4 for both deaths and DALYs. Much larger differences, up to a factor of 40, were noted when SMRs from different previous studies were utilized by Method (I). Thus, the death and DALYs calculations are most sensitive to the choice of dose-response model and less so to the calculation method. The differences are also partly ascribed to different background (i.e. for As non-exposed populations) rates for lung, bladder and liver cancers between Chakdha block and Taiwan. However, the differences also highlight some of systematic uncertainties in the application of epidemiological studies in one part of the world to another, emphasizing that accurate health risk estimates are likely to be better obtained by large scale systematic surveys of health outcomes in the study population. Irrespective of the comparability of the results of the two methods, it is noted that the lack of detailed consideration of confounding factors such as genetic polymorphisms, smoking and dietary habits, and, in particular, exposure to As through other routes, notably ingestion of As-bearing rice, may significantly impact on the accuracy of the results obtained by either method.

  36. A comparison of two techniques for calculating groundwater arsenic- related lung, bladder and liver cancer disease burden using data from Chakdha block, West Bengal

    Debapriya Mondal, George C. D. Adamson, Ross Nickson and David A. Polya.

    Applied Geochemistry, Vol. 23, No. 11, Nov 2008, pp. 2998-3008.

    Calculation of excess disease burden for As exposed populations is becoming increasingly important to enable quantitative estimation of the impacts of various As mitigation options. There are several methods by which such calculations may be carried out. In this study, two methods, recently applied to estimating groundwater As-related health risks in southern Asia, to estimate disease burden arising from lung, bladder and liver cancer from As exposure for an As-effected area of West Bengal have been compared. Both utilized calculated distributions of exposure of the studied population to As from groundwater. Method (I) then entailed calculating disease burden by combining published background rates for death and disability adjusted life years (DALYs) and standard mortality ratios (SMRs) for excess health impacts related to As exposure, whilst for Method (II), disease burden from As exposure was estimated using the basic DALY formula, combined with incidence rates based on the NRC multistage Weibull model. Dose-response data for both methods were based on studies in Taiwan. When the same dose-response model was used for both methods, the two methods were broadly comparable, agreeing to within a factor of 4 for both deaths and DALYs. Much larger differences, up to a factor of 40, were noted when SMRs from different previous studies were utilized by Method (I). Thus, the death and DALYs calculations are most sensitive to the choice of dose-response model and less so to the calculation method. The differences are also partly ascribed to different background (i.e. for As non-exposed populations) rates for lung, bladder and liver cancers between Chakdha block and Taiwan. However, the differences also highlight some of systematic uncertainties in the application of epidemiological studies in one part of the world to another, emphasizing that accurate health risk estimates are likely to be better obtained by large scale systematic surveys of health outcomes in the study population. Irrespective of the comparability of the results of the two methods, it is noted that the lack of detailed consideration of confounding factors such as genetic polymorphisms, smoking and dietary habits, and, in particular, exposure to As through other routes, notably ingestion of As-bearing rice, may significantly impact on the accuracy of the results obtained by either method.

  37. Dietary intake of arsenic, cadmium, mercury, and lead by the population of Catalonia, Spain

    Roser MartÝ-Cid, Juan M. Llobet, Victoria Castell and JosÚ L. Domingo.

    Biological trace element research, Vol. 125, No. 2, Nov 2008, pp. 120-132.

    The concentrations of arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) were determined in samples of food items widely consumed by the population of Catalonia, Spain. All samples were randomly acquired in 12 cities of Catalonia between March and June of 2006 and analyzed by inductively coupled plasma mass spectrometry. The dietary intake of these elements was estimated for various age-gender groups of population: children, adolescents, adults, and seniors. In order to determine the temporal trend on the dietary exposure to As, Cd, Hg, and Pb, the current results were compared with those of a previous survey (2000). In the present market basket study, for a standard male adult of 70-kg body weight living in Catalonia, the dietary intakes of As, Cd, Hg, and Pb were 261.01, 9.80, 12.61, and 45.13 microg/day, respectively, while in the 2000 survey, these intakes were 223.59, 15.73, 21.22, and 28.37 microg/day, for As, Cd, Hg, and Pb, respectively. For As, the only food groups currently contributing with measurable amounts to intake of total As were fish and shellfish and cereals, while for Cd the highest contribution to total intake corresponded to pulses, tubers, and cereals. For Hg, the contribution was only due to fish and shellfish, while cereals were the group with the highest contribution to total Pb intake. The estimated intakes of As, Cd, Hg, and Pb are notably lower than the respective provisional tolerable weekly intakes, which indicate that these intakes should not mean additional health risks for the consumers.

  38. Ecotoxicology of arsenic in the hydrosphere: Implications for public health

    B. C. Gbaruko, G. R. E. E. Ana and J. K. Nwachukwu.

    African Journal of Biotechnology, Vol. 7, No. 25, 29 Dec 2008, pp. 4737-4742.

    Arsenic is a naturally occurring metalloid element that is found in soil, air and water. Environmental arsenic exists in both organic and inorganic states. Organic arsenicals are generally considered non toxic, whereas inorganic forms are toxic. The most acutely toxic form is arsine gas. Inorganic arsenic exists predominantly in trivalent (As super(3+)) and pentavalent (As super(5+)) forms, where trivalent compounds are more toxic than pentavalent ones. Human activities have also intensified arsenic accumulation in the environment. Organs most susceptible to arsenic toxicity are those involved with absorption, accumulation or excretion, including the skin, circulatory system, gastrointestinal tract, liver and kidney. Arsenic is associated with multiple health effects, including Blackfoot diseases, diabetes, hypertension, peripheral neuropathy and multiple vascular diseases. Other effects include anemia, liver damage, portal cirrhosis, hematopoietic depression, anhydremia, sensory disturbance and weight loss. In addition to acute toxicity, long-term exposure to inorganic arsenic is associated with certain forms of cancer of the skin, lung, colon, bladder, liver and breast. Understanding the ecotoxicological effects of arsenic in the environment is paramount to mitigating its deleterious effects on ecological and human health. This paper is therefore a review of the ecotoxicological effects of arsenic on human and ecological health.

  39. Effect of in situ soil amendments on arsenic uptake in successive harvests of ryegrass (Lolium perenne cv Elka) grown in amended As-polluted soils

    William Hartley and Nicholas W. Lepp.

    Environmental pollution (Barking, Essex : 1987), Vol. 156, No. 3, Dec 2008, pp. 1030-1040.

    Several iron-bearing additives, selected for their potential ability to adsorb anions, were evaluated for their effectiveness in attenuation of arsenic (As) in three soils with different sources of contamination. Amendments used were lime, goethite (alpha-FeOOH) (crystallised iron oxide) and three iron-bearing additives, iron grit, Fe(II) and Fe(III) sulphates plus lime, applied at 1% w/w. Sequential extraction schemes conducted on amended soils determined As, Cu, Zn and Ni fractionation. Plant growth trials using perennial ryegrass (Lolium perenne var. Elka) assessed shoot As uptake. This was grown in the contaminated soils for 4 months, during which time grass shoots were successively harvested every 3 weeks. Goethite increased biomass yields, but clear differences were observed in As transfer rates with the various iron oxides. In conclusion, whilst Fe-oxides may be effective in situ amendments, reducing As bioavailability, their effects on plant growth require careful consideration. Soil-plant transfer of As was not completely halted by any amendment.

  40. Four years of development and field-testing of IHE arsenic removal family filter in rural Bangladesh

    B. Petrusevski, S. Sharma, WG van der Meer, et al.

    2008, 53-58

    UNESCO-IHE has been developing an arsenic removal family filter with a capacity of 100L/day based on arsenic adsorption onto iron oxide coated sand, a by-product of iron removal plants. The longer term and field conditions performance of the third generation of eleven family filters prototypes were tested in rural Bangladesh for 30 months. All filters achieved initially highly effective arsenic removal irrespective of arsenic concentration and groundwater composition. Arsenic level in filtrate reached 10 mu g/l after 50 days of operation at one testing site and after 18 months of continuous operation at other 3 testing sites. Arsenic level at other 7 sites remained below the WHO guideline value till the end of study. Positive correlation was found between arsenic removal capacity of the filter and iron concentration in groundwater. In addition to arsenic, iron present in groundwater at all testing sites was also removed highly effectively. Manganese removal with IHE family filter was effective only when treating groundwater with low ammonia. A simple polishing sand filter, after IHE family filter, resulted in consistent and effective removal of manganese. IHE family filters were easy to operate and were well accepted by the local population.

  41. Geochemistry of aquifer sediments and arsenic-rich groundwaters from Kandal Province, Cambodia

    Helen A. L. Rowland, Andrew G. Gault, Paul Lythgoe and David A. Polya.

    Applied Geochemistry, Vol. 23, No. 11, Nov 2008, pp. 3029-3046.

    Elevated As is well known to be present in aquifers utilised for drinking water and irrigation in West Bengal and Bangladesh. This problem has also more recently been discovered in other parts of Asia, including Vietnam, Cambodia, Inner Mongolia and the Middle Ganges Plain. Analysis of groundwaters in Kandal Province of Cambodia found waters with comparable geochemistry to the As-rich groundwaters of the West Bengali Delta. Similarities included high but heterogeneous As distributions, predominantly in the form As(III), high Fe, moderate to high [View the MathML source], circumneutral pH, low [View the MathML source] and geochemical components indicative of reducing conditions. Good positive correlations between As, Fe, [View the MathML source] and [View the MathML source], and dissolved organic C is consistent with As release predominantly via microbially mediated reductive dissolution of As bearing Fe(III) oxides. Further evidence for such a process is found from correlations between As, Fe and organic matter from analysis of aquifer sediments, by the presence of goethite in the finer fractions and from the association of As with amorphous, poorly crystalline and well crystallised hydrous Fe oxides. The presence of several high As, but low Fe, wells implies that microbes could have a more direct role in mediating As release via the direct utilisation of Fe(III) or As(V) as electron acceptors. The presence of elevated As in waters with short aquifer residence times (as indicated by their geochemical signature) highlights the possible vulnerability of these aquifers to the influx of surface derived waters, providing an additional source of labile organic C that could exacerbate As release by stimulating microbial activity.

  42. Geomorphic controls on groundwater arsenic distribution in the Mekong River delta, Cambodia

    Nicholas C. Papacostas, Benjamin C. Bostick, Andrew N. Quicksall, Joshua D. Landis and Michael Sampson.

    Geology (Boulder), Vol. 36, No. 11, Nov 2008, pp. 891-894.

    Natural arsenic contamination of groundwater is a severe public health crisis affecting nearly 60 million people in South Asia and Southeast Asia alone. Contamination is spatially heterogeneous and results from the coupled microbial decomposition of organic matter and reductive dissolution of arsenic-bearing iron minerals. Here we demonstrate that elevated arsenic concentrations arise in regions of recent organic matter deposition and thus are controlled by fluvial geomorphic processes. Arsenic contamination is best expressed within recent geomorphic features such as docked islands, scroll bars, and avulsions. Within these features, the deposition of rapidly buried reactive organic matter facilitates microbial iron reduction and arsenic release. Ultimately, the organic matter supply is exhausted and the conditions necessary for soluble arsenic to persist diminish.

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

    K. Kurosawa, K. Egashira, M. Tani, M. Jahiruddin, A. Z. Moslehuddin and Z. Md Rahman.

    Environmental Pollution, Vol. 156, No. 2, Nov 2008, pp. 563-565.

    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.

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

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

    Environmental pollution (Barking, Essex : 1987), Vol. 156, No. 2, Nov 2008, pp. 563-565.

    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.

  45. How can biologically-based modeling of arsenic kinetics and dynamics inform the risk assessment process? - A workshop review

    E. M. Kenyon, W. T. Klimecki, H. El-Masri, R. B. Conolly, H. J. Clewell and B. D. Beck.

    Toxicology and applied pharmacology, Vol. 232, No. 3, 1 Nov 2008, pp. 359-368.

    Quantitative biologically-based models describing key events in the continuum from arsenic exposure to the development of adverse health effects provide a framework to integrate information obtained across diverse research areas. For example, genetic polymorphisms in arsenic metabolizing enzymes can lead to differences in target tissue dosimetry for key metabolites causative in toxic and carcinogenic response. This type of variation can be quantitatively incorporated into pharmacokinetic (PK) models and used together with population-based modeling approaches to evaluate the impact of genetic variation in methylation capacity on dose of key metabolites to target tissue. The PK model is an essential bridge to the pharmacodynamic (PD) models. A particular benefit of PD modeling for arsenic is that alternative models can be constructed for multiple proposed modes of action for arsenicals. Genomics data will prove useful for identifying the key pathways involved in particular responses and aid in determining other types of data needed for quantitative modeling. These models, when linked with PK models, can be used to better understand and explain dose- and time-response behaviors. This in turn assists in prioritizing modes of action with respect to their risk assessment relevance and future research. This type of integrated modeling approach can form the basis for a highly informative mode-of-action directed risk assessment for inorganic arsenic (iAs). This paper will address both practical and theoretical aspects of integrating PK and PD data in a modeling framework, including practical barriers to its application.

  46. How can biologically-based modeling of arsenic kinetics and dynamics inform the risk assessment process? - A workshop review

    Elaina M. Kenyon, Walter T. Klimecki, Hisham El-Masri, Rory B. Conolly, Harvey J. Clewell and Barbara D. Beck.

    Toxicology and applied pharmacology, 2008 Nov 1, Vol. 232, No. 3, 2008, pp. 359-368.

    Quantitative biologically-based models describing key events in the continuum from arsenic exposure to the development of adverse health effects provide a framework to integrate information obtained across diverse research areas. For example, genetic polymorphisms in arsenic metabolizing enzymes can lead to differences in target tissue dosimetry for key metabolites causative in toxic and carcinogenic response. This type of variation can be quantitatively incorporated into pharmacokinetic (PK) models and used together with population-based modeling approaches to evaluate the impact of genetic variation in methylation capacity on dose of key metabolites to target tissue. The PK model is an essential bridge to the pharmacodynamic (PD) models. A particular benefit of PD modeling for arsenic is that alternative models can be constructed for multiple proposed modes of action for arsenicals. Genomics data will prove useful for identifying the key pathways involved in particular responses and aid in determining other types of data needed for quantitative modeling. These models, when linked with PK models, can be used to better understand and explain dose- and time-response behaviors. This in turn assists in prioritizing modes of action with respect to their risk assessment relevance and future research. This type of integrated modeling approach can form the basis for a highly informative mode-of-action directed risk assessment for inorganic arsenic (iAs). This paper will address both practical and theoretical aspects of integrating PK and PD data in a modeling framework, including practical barriers to its application.

  47. Phytostabilisation of arsenical gold mine tailings using four Eucalyptus species: Growth, arsenic uptake and availability after five years

    D. J. King, A. I. Doronila, C. Feenstra, A. J. M. Baker and I. E. Woodrow.

    Science of the Total Environment, Vol. 406, No. 1-2, 15 Nov 2008, pp. 35-42.

    Arsenic (As) contamination is a worldwide problem. Where arsenic is highly concentrated and confined within a limited area, such as in many mine tailings facilities, phytostabilisation is an attractive technology for long-term remediation. Important characteristics of a plant to be useful for phytostabilisation include As tolerance and low levels of As accumulation, as well as the ability to limit As availability. Performance needs to be monitored over the long term to ensure an ongoing vegetation community, though this is rarely done. In this study, the suitability of four Eucalyptus species (E. cladocalyx, E. melliodora, E. polybractea, E. viridis) for the phytostabilisation of arsenical, sulphidic gold mine tailings was assessed after five years. All four species accumulated low As concentrations, the highest being recorded in mature leaves, ranging from 0.29 to 5.14 mu g g super(-) super(1) As. E. polybractea had significantly higher foliar As than the other three species but there was also great variation within the species. Between 5-10 times lower concentrations were recorded in stem samples and no As was detected in young leaf tips. There was also significant variation in the growth of trees upon the site. Eucalyptus cladocalyx grew significantly taller than other species although greater variation was detected within the species than between. The variation in tree heights was not correlated with As concentrations in either stems or leaves. Arsenic availability was determined to depths of 2.2 m and found to be low when compared to total As in the tailings. Importantly, no effect of trees on As availability or soil pH was detected. We conclude that E. cladocalyx, in particular is an ideal candidate for the long-term phytostabilisation of As-contaminated land and mine tailings. The variation detected in both As accumulation and growth is also promising for the selection of desirable traits.

  48. Rice is a major exposure route for arsenic in Chakdaha block, Nadia district, West Bengal, India; a probabilistic risk assessment; Arsenic in ground waters of Southeast Asia; with emphasis on Cambodia and Vietnam

    D. Mondal and D. A. Polya.

    Applied Geochemistry, Vol. 23, No. 11, Nov 2008, pp. 2987-2998.

    The importance or otherwise of rice as an exposure pathway for As ingestion by people living in Bengal and other areas impacted by hazardous As-bearing groundwaters is currently a matter of some debate. Here this issue is addressed by determining the overall increased cancer risk due to ingestion of rice in an As-impacted district of West Bengal. Human target cancer health risks have been estimated through the intake of As-bearing rice by using combined field, laboratory and computational methods. Monte Carlo simulations were run following fitting of model probability curves to measured distributions of (i) As concentration in rice and drinking water and (ii) inorganic As content of rice and fitting distributions to published data on (i) ingestion rates and (ii) body weight and point estimates on bioconcentration factors, exposure duration and other input variables. The distribution of As in drinking water was found to be substantially lower than that reported by previous authors for As in tube wells in the same area, indicating that the use of tube well water as a proxy for drinking water is likely to result in human health risks being somewhat overestimated. The calculated median increased lifetime cancer risk due to cooked rice intake was 7.62x10 (super -4) , higher than the 10 (super -4) -10 (super -6) range typically used by the USEPA as a threshold to guide determination of regulatory values and similar to the equivalent risk from water intake. The median total risk from combined rice and water intake was 1.48x10 (super -3) . The contributions to this median risk from drinking water, rice and cooking of rice were found to be 48%, 44% and 8%, respectively. Thus, rice is a major potential source of As exposure in the As-affected study areas in West Bengal and the most important exposure pathway for groups exposed to low or no As in drinking water.

  49. Spatial variability of arsenic concentration in soils and plants, and its relationship with iron, manganese and phosphorus

    M. B. Hossain, M. Jahiruddin, G. M. Panaullah, R. H. Loeppert, M. R. Islam and J. M. Duxbury.

    Environmental Pollution, Vol. 156, No. 3, Dec 2008, pp. 739-744.

    Spatial distribution of arsenic (As) concentrations of irrigation water, soil and plant (rice) in a shallow tube-well (STW) command area (8ha), and their relationship with Fe, Mn and P were studied. Arsenic concentrations of water in the 110m long irrigation channel clearly decreased with distance from the STW point, the range being 68-136 mu gL super(-) super(1). Such decreasing trend was also noticed with Fe and P concentrations, but the trend for Mn concentrations was not remarkable. Concerning soil As, the concentration showed a decreasing tendency with distance from the pump. The NH sub(4)-oxalate extractable As contributed 36% of total As and this amount of As was associated with poorly crystalline Fe-oxides. Furthermore only 22% of total As was phosphate extractable so that most of the As was tightly retained by soil constituents and was not readily exchangeable by phosphate. Soil As (both total and extractable As) was significantly and positively correlated with rice grain As (0.296+/-0.063 mu gg super(-) super(1), n=56). Next to drinking water, rice could be a potential source of As exposure of the people living in the As affected areas of Bangladesh.

  50. Arsenic mitigation in Bangladesh: National screening data and case studies in three upazilas

    Richard B. Johnston and Motaleb H. Sarker.

    Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances & Environmental Engineering, Vol. 42, No. 12, Oct 2007, pp. 1889-1896.

    Since 2000, nearly 5 million wells in Bangladesh have been tested for arsenic. Results of this survey are presented, and it is estimated that approximately 20% of tube wells nationwide contain arsenic above the drinking water limit of 50 parts per billion, with approximately 20 million people at risk of consuming water above this limit. Three case studies in arsenic mitigation are presented, which indicate that substantial progress has been made in raising awareness about arsenic. Substantial differences were found in tubewell surveys made in 2001 and 2005, with 17% of tubewells painted green in 2001 showing arsenic above 50 ppb in 2005, and 12% of tubewells painted red in 2001 showing 50 ppb arsenic or less in 2005. In 38% of households having red tubewells, household water was found to contain 50 ppb arsenic or less, indicating substantial behaviour change. In two upazilas where safe alternatives (primarily safe shallow tubewells and newly installed deep tubewells) are available, 52% and 75% of people at risk were found to have arsenic-safe water in the household, indicating that they have changed their drinking water sources. In a third upazila where safe alternatives are scarce, less than 10% of people at risk were found to have safe water in the home. The greatest challenges remain in areas where contamination is high but installation of new safe water points is constrained for technical reasons (e.g. unsuitability of the deep aquifer).