Arsenic groundwater contamination and its health effects in the state of Uttar Pradesh (UP) in upper and middle Ganga plain, India: a severe danger

This communication presents results of our 2-year survey on groundwater arsenic contamination in three districts Ballia, Varanasi and Gazipur of Uttar Pradesh (UP) in the upper and middle Ganga plain, India. Analyses of 4,780 tubewell water samples revealed that arsenic concentrations in 46.5% exceeded 10 microg/L, in 26.7%, 50 microg/L and in 10% 300 microg/L limits. Arsenic concentrations up to 3,192 microg//L were observed. The age of tubewells (n=1,881) ranged from less than a year to 32 years, with an average of 6.5 years. Our study shows that older tubewells had a greater chance of contamination. Depth of tubewells (n=3,810) varied from 6 to 60.5 m with a mean of 25.75 m. A detailed study in three administrative units within Ballia district, i.e. block, Gram Panchayet, and village was carried out to assess the magnitude of the contamination. Before our survey the affected villagers were not aware that they were suffering from arsenical toxicity through contaminated drinking water. A preliminary clinical examination in 11 affected villages (10 from Ballia and 1 from Gazipur district) revealed typical arsenical skin lesions ranging from melanosis, keratosis to Bowens (suspected). Out of 989 villagers (691 adults, and 298 children) screened, 137 (19.8%) of the adults and 17 (5.7%) of the children were diagnosed to have typical arsenical skin lesions. Arsenical neuropathy and adverse obstetric outcome were also observed, indicating severity of exposure. The range of arsenic concentrations in hair, nail and urine was 137-10,900, 764-19,700 microg/kg, and 23-4,030 microg/L, respectively. The urine, hair and nail concentrations of arsenic correlated significantly (r=0.76, 0.61, and 0.55, respectively) with drinking water arsenic concentrations. The similarity to previous studies on arsenic contamination in West Bengal, Bihar and Bangladesh indicates that people from a significant part of the surveyed areas in UP are suffering and this will spread unless drives to raise awareness of arsenic toxicity are undertaken and an arsenic safe water supply is immediately introduced.     

Magnitude of arsenic pollution in the Mekong and Red River Deltas--Cambodia and Vietnam

Large alluvial deltas of the Mekong River in southern Vietnam and Cambodia and the Red River in northern Vietnam have groundwaters that are exploited for drinking water by private tube-wells, which are of increasing demand since the mid-1990s. This paper presents an overview of groundwater arsenic pollution in the Mekong delta: arsenic concentrations ranged from 1-1610 microg/L in Cambodia (average 217 microg/L) and 1-845 microg/L in southern Vietnam (average 39 microg/L), respectively. It also evaluates the situation in Red River delta where groundwater arsenic concentrations vary from 1-3050 microg/L (average 159 microg/L). In addition to rural areas, the drinking water supply of the city of Hanoi has elevated arsenic concentrations. The sediments of 12-40 m deep cores from the Red River delta contain arsenic levels of 2-33 microg/g (average 7 microg/g, dry weight) and show a remarkable correlation with sediment-bound iron. In all three areas, the groundwater arsenic pollution seem to be of natural origin and caused by reductive dissolution of arsenic-bearing iron phases buried in aquifers. The population at risk of chronic arsenic poisoning is estimated to be 10 million in the Red River delta and 0.5-1 million in the Mekong delta. A subset of hair samples collected in Vietnam and Cambodia from residents drinking groundwater with arsenic levels >50 microg/L have a significantly higher arsenic content than control groups (<50 microg/L). Few cases of arsenic related health problems are recognized in the study areas compared to Bangladesh and West Bengal. This difference probably relates to arsenic contaminated tube-well water only being used substantially over the past 7 to 10 years in Vietnam and Cambodia. Because symptoms of chronic arsenic poisoning usually take more than 10 years to develop, the number of future arsenic related ailments in Cambodia and Vietnam is likely to increase. Early mitigation measures should be a high priority.     

High exposure to arsenic from drinking water at several localities in eastern Croatia

This study investigated the relationship between arsenic concentrations in drinking water in four towns/villages in eastern Croatia and corresponding hair arsenic concentrations of residents. The mean arsenic concentrations in community drinking water samples were 0.14, 37.88, 171.60, and 611.89 microg/l. The corresponding mean concentrations of the element in hair samples of subjects residing in each of the localities were 0.07 (n=11), 0.26 (n=17), 1.74 (n=11), and 4.31 microg/g (n=23). Chronic exposures to arsenic levels estimated in three investigated locations could present a serious health threat to around 3% of Croatian population.     

Effects of time and point-of-use devices on arsenic levels in Southeastern Michigan drinking water, USA

Health effects associated with chronic, low-level exposures to arsenic in drinking water (<100 microg/L) remain unclear, in part due to uncertainties in assessing exposure. Drinking water concentrations have been used to assess past exposure to arsenic in epidemiological studies, under the assumption that a single measurement can be used to estimate historical exposure. This study aims to better understand (1) temporal variability in arsenic concentrations in drinking water and (2) the impact of point-of-use (POU) treatment devices on arsenic exposure measurements, and on reliability of the exposure measurement for population-level studies. Multiple drinking water samples were collected at two points in time (an average of fourteen months apart) for 261 individuals enrolled in a case-control study of arsenic exposure and bladder cancer in Michigan. Sources of drinking water included private wells (n = 221), public water supplies (n = 33), and bottled water (n = 7); mean arsenic concentration was highest in private wells (7.28 microg/L) and lowest in bottled water samples (0.28 microg/L). Arsenic concentrations in primary drinking water samples were highly correlated (r = 0.88, p < 0.0001, n = 196), with 3% of the water sources exceeding the United States Environmental Protection Agency's Maximum Contaminant Level (MCL) in one sample but not in the other sample. Measurement reproducibility did not vary by type of POU device (e.g., softener, filter, reverse osmosis system). Arsenic concentrations did differ, however, between samples treated with POU devices and untreated samples taken on the same day. Substantial differences in arsenic concentrations were consistently observed for reverse osmosis systems; other POU devices had variable effects on arsenic concentrations. These results indicate that while a single residential arsenic measurement may be used to represent exposure in this region, researchers must obtain information on changes in water source and POU treatment devices to better characterize population exposures over time.     

Impact of irrigating rice paddies with groundwater containing arsenic in Bangladesh

Soil and soil-water As profiles were obtained from 4 rice paddies in Bangladesh during the wet growing season (May-November), when surface water with little arsenic is used for irrigation, or during the dry season (January-May), when groundwater elevated in arsenic is used instead. In the upper 5 cm of paddy soil, accumulation of 13+/-12 mg/kg acid-leachable As (n=11) was observed in soil from 3 sites irrigated with groundwater containing 80-180 microg/L As, whereas only 3+/-2 mg/kg acid-leachable As (n=8) was measured at a control site. Dissolved As concentrations averaged 370+/-340 microg/L (n=7) in the upper 5 cm of the soil at the 3 sites irrigated with groundwater containing 80-180 microg/L As, contrasting with soil water As concentrations of only 18+/-7 microg/L (n=4) over the same depth interval at the control site. Despite the accumulation of As in soil and in soil water attributable to irrigation with groundwater containing elevated As levels, there is no evidence of a proportional transfer to rice grains collected from the same sites. Digestion and analysis of individual grains of boro winter rice from the 2 sites irrigated with groundwater containing 150 and 180 microg/L As yielded concentrations of 0.28+/-0.13 mg/kg (n=12) and 0.44+/-0.25 mg/kg (n=12), respectively. The As content of winter rice from the control site was not significantly different though less variable (0.30+/-0.07; n=12). The observations suggest that exposure of the Bangladesh population to As contained in rice is less of an immediate concern than the continued use of groundwater containing elevated As levels for drinking or cooking, or other potential consequences of As accumulation in soil and soil-water.     

The magnitude of arsenic contamination in groundwater and its health effects to the inhabitants of the Jalangi--one of the 85 arsenic affected blocks in West Bengal, India

To better understand the magnitude of arsenic contamination in groundwater and its effects on human beings, a detailed study was carried out in Jalangi, one of the 85 arsenic affected blocks in West Bengal, India. Jalangi block is approximately 122 km2 in size and has a population of 215538. Of the 1916 water samples analyzed (about 31% of the total hand tubewells) from the Jalangi block, 77.8% were found to have arsenic above 10 microg l(-1) [the World Health Organization (WHO)-recommended level of arsenic in drinking water], 51% had arsenic above 50 microg l(-1) (the Indian standard of permissible limit of arsenic in drinking water) and 17% had arsenic at above 300 microg l(-1) (the concentration predicting overt arsenical skin lesions). From our preliminary medical screening, 1488 of the 7221 people examined in the 44 villages of Jalangi block exhibit definite arsenical skin lesions. An estimation of probable population that may suffer from arsenical skin lesions and cancer in the Jalangi block has been evaluated comparing along with international data. A total of 1600 biologic samples including hair, nail and urine have been analyzed from the affected villages of Jalangi block and on an average 88% of the biologic samples contain arsenic above the normal level. Thus, a vast population of the block may have arsenic body burden. Cases of Bowen's disease and cancer have been identified among adults who also show arsenical skin lesions and children in this block are also seriously affected. Obstetric examinations were also carried out in this block.     

Field and laboratory arsenic speciation methods and their application to natural-water analysis

The toxic and carcinogenic properties of inorganic and organic arsenic species make their determination in natural water vitally important. Determination of individual inorganic and organic arsenic species is critical because the toxicology, mobility, and adsorptivity vary substantially. Several methods for the speciation of arsenic in groundwater, surface-water, and acid mine drainage sample matrices using field and laboratory techniques are presented. The methods provide quantitative determination of arsenite [As(III)], arsenate [As(V)], monomethylarsonate (MMA), dimethylarsinate (DMA), and roxarsone in 2-8 min at detection limits of less than 1 microg arsenic per liter (microg As L(-1)). All the methods use anion exchange chromatography to separate the arsenic species and inductively coupled plasma-mass spectrometry as an arsenic-specific detector. Different methods were needed because some sample matrices did not have all arsenic species present or were incompatible with particular high-performance liquid chromatography (HPLC) mobile phases. The bias and variability of the methods were evaluated using total arsenic, As(III), As(V), DMA, and MMA results from more than 100 surface-water, groundwater, and acid mine drainage samples, and reference materials. Concentrations in test samples were as much as 13,000 microg As L(-1) for As(III) and 3700 microg As L(-1) for As(V). Methylated arsenic species were less than 100 microg As L(-1) and were found only in certain surface-water samples, and roxarsone was not detected in any of the water samples tested. The distribution of inorganic arsenic species in the test samples ranged from 0% to 90% As(III). Laboratory-speciation method variability for As(III), As(V), MMA, and DMA in reagent water at 0.5 microg As L(-1) was 8-13% (n=7). Field-speciation method variability for As(III) and As(V) at 1 microg As L(-1) in reagent water was 3-4% (n=3).     

Arsenic speciation and uranium concentrations in drinking water supply wells in Northern Greece: correlations with redox indicative parameters and implications for groundwater treatment

The cities in the Aksios and Kalikratia areas in Northern Greece rely on arsenic contaminated groundwater for their municipal water supply. As remedial action strongly depends on arsenic speciation, the presence of other possible contaminants, and on the general water composition, a detailed study with samples from 21 representative locations was undertaken. Arsenic concentrations were typically 10-70 microg/L. In the groundwaters of the Aksios area with lower Eh values (87-172 mV), pH 7.5-8.2 and 4-6 mM HCO(3) alkalinity, As(III) predominated. Manganese concentrations were mostly above the EC standard of 0.05 mg/L (0.1-0.7 mg/L). In groundwaters of the Kalikratia area with higher Eh values (272-352 mV), pH 6.7-7.5 and 6-12 mM HCO(3) alkalinity, As(V) was the main species. Uranium in the groundwaters was also investigated and correlations with total arsenic concentrations and speciation were examined to understand more of the redox chemistry of the examined groundwaters. Uranium concentrations were in the range 0.01-10 microg/L, with the higher concentrations to occur in the oxidizing groundwaters of the Kalikratia area. Uranium and total arsenic concentrations showed no correlation, whereas uranium concentrations correlated strongly with As(III)/As(tot) ratios, depicting their use as a possible indicator of groundwater redox conditions. Finally, boron was found to exceed the EC drinking water standard of 1 mg/L in some wells in the Kalikratia area and its removal should also be considered in the design of a remedial action.     

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

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 μg/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 μg/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 μg As/g for hair and < 0.5-4.2 μg/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.     

Respiratory effects in people exposed to arsenic via the drinking water and tobacco smoking in southern part of Pakistan

In this study, a survey has been conducted during 2005-2007 on surface and groundwater arsenic (As) contamination and its impact on the health of local population, of villages located on the banks of Manchar lake, southern part of Sindh, Pakistan. We have also assessed the relationship between arsenic exposure through respiratory disorders in male subjects with drinking water and smoking cigarettes made from tobacco grown in agricultural land irrigated with As contaminated lake water. The biological samples (blood and scalp hair) were collected from As exposed subjects (100% smokers) and age matched healthy male subjects (40.2% smoker and 59.8% non smokers) belong to unexposed areas for comparison purposes. The As concentration in drinking water (surface and underground water), agricultural soil, cigarette tobacco and biological samples were determined by electrothermal atomic absorption spectrometry. The range of As concentrations in lake water was 35.2-158 µg/L (average 97.5 µg/L), which is 3-15 folds higher than permissible limit of World Health Organization (WHO, 2004). While the As level in local cigarette tobacco was found to be 3-6 folds higher than branded cigarettes (0.37-0.79 µg/g). Arsenic exposed subjects (with and without RD) had significantly elevated levels of As in their biological samples as compared to referent male subject of unexposed area. These respiratory effects were more pronounced in individuals who had also As induced skin lesions. The linear regressions showed good correlations between As concentrations in water versus hair and blood samples of exposed subjects with and without respiratory problems.     

Evaluation of potential health risk of arsenic-affected groundwater using indicator kriging and dose response model

This study analyzed the potential health risk associated with the ingestion of arsenic-affected groundwater in the arseniasis-endemic Lanyang plain of northeastern Taiwan. Indicator kriging was used to estimate arsenic concentrations in groundwater. Target cancer risk (TR) and dose response functions were adopted to evaluate the potential health risk based on the estimated arsenic concentration distributions. The estimated arsenic concentrations in groundwater reveal that arsenic concentrations (>50 microg/L) in well water are high in six townships - JiaoSi, YiLan, JhungWei, WuJie, DonShan and LouDon. Highest arsenic concentrations (70.32 microg/L) are in the YiLan and the JhungWei townships. The estimated TR values at the arsenic-affected townships are ten times more than an acceptable standard (10(-6)). The largest TR values are 145.5 and 91.2 times higher than an acceptable standard for males and females, respectively. The estimated annual mortalities by arsenic-induced internal cancers occur in the YiLan township (ten cases), LouDon (five cases), WuJie (three cases), JhungWei (two cases) and DonShan (one case). The highest number of mortalities per year in the study area is 24. Residents of the six townships with high arsenic-affected groundwater should use tap water as drinking water and use groundwater only for other purpose. The well water in other townships in the Lanyang plain has no adverse effects on human health.     

Health risk assessment of inorganic arsenic intake of Cambodia residents through groundwater drinking pathway

In order to compare the magnitudes and health impacts of arsenic and other toxic trace elements in well water, groundwater and hair samples were collected from three areas with different arsenic exposure scenarios in the Mekong River basin of Cambodia. Ampil commune in Kampong Cham province was selected as an uncontaminated area, Khsarch Andaet commune in Kratie province was selected as a moderately contaminated area, and Kampong Kong commune in Kandal Province was selected as an extremely contaminated area. Results of ICP-MS analyses of the groundwater samples revealed that As, Mn, Fe and Ba concentrations were significantly different among the three study areas (Kruskal-Wallis test, p < 0.0001). Out of 46 observed wells in the Kandal province study area, 100% detected As > 50 μg L⁻¹ and Fe > 300 μg L⁻¹; 52.17% had Mn > 400 μg L⁻¹ and 73.91% found Ba > 700 μg L⁻¹. In the Kratie province study area (n = 12), 25% of wells showed elevated arsenic levels above 10 μg L⁻¹ and 25% had Mn > 400 μg L⁻¹, whereas samples from Kampong Cham province study area (n = 18) were relatively clean, with As < 10 μg L⁻¹. A health risk assessment model derived from the USEPA was applied to calculate individual risks resulting from drinking groundwater. Computational results indicated that residents from Kandal Province study area (n = 297) confronted significantly higher non-carcinogenic and carcinogenic risks than those in Kratie (n = 89) and Kampong Cham (n = 184) province study areas (Kruskal-Wallis test, p < 0.0001). 98.65% of respondents from the Kandal province study area were at risk for the potential non-cancer effect and an average cancer risk index was found to be 5 in 1000 exposure. The calculations also indicated that, in the Kratie province study area, 13.48% of respondents were affected by non-cancer health risks and 33.71% were threatened by cancer, whereas none of respondents in the Kampong Cham province study area appeared to have non-carcinogenic effect. Positively significant correlations of the arsenic content in scalp hair (As_h) with both arsenic levels in groundwater (As_w) (r_s (304) = 0.757, p < 0.0001) and individual average daily doses (ADD) of arsenic (r_s (304) = 0.763, p < 0.0001) undoubtedly indicated that arsenic accumulation in the bodies of Cambodia residents in the Mekong River basin was mainly through a groundwater drinking pathway. To the best of our knowledge, this is the first comprehensive report comparing individual health risk assessments of arsenic exposure through a groundwater drinking pathway to enriched arsenic levels from groundwater in the Mekong River basin, Cambodia. This study indicates that elevated arsenic concentrations in groundwater may lead to thousands of cases of arsenicosis in the near future if mitigating actions are not taken.     

A Weibull-PBPK model for assessing risk of arsenic-induced skin lesions in children

Chronic arsenic exposure and skin lesions (keratosis and hyperpigmentation) are inextricably linked. This paper was to quantify the children skin lesions risks and to further recommend safe drinking water arsenic standard based on reported arsenic epidemiological data. We linked the Weibull dose-response function and a physiologically based pharmacokinetic (PBPK) model to estimate safe drinking water arsenic concentrations and to perform the risk characterization. We calculated odds ratios (ORs) to assess the relative magnitude of the effect of the arsenic exposure on the likelihood of the prevalence of children skin lesions by calculating proposed Weibull-based prevalence ratios of exposed to control groups associated with the age group-specific PBPK model predicted dimethylarsinite (MMA(III)) levels in urine. Positive relationships between arsenic exposures and cumulative prevalence ratios of skin lesions were found using Weibull dose-response model (r2=0.91-0.96). We reported that the safe drinking water arsenic standards were recommended to be 2.2 and 1 microg/L for male and 6 and 2.8 microg/L for female in 0-6 and 7-18 years age groups, respectively, based on hyperpigmentation with an excess risk of 10(-3) for a 75 years lifetime exposure. Risk predictions indicate that estimated ORs have 95% confidence intervals of 1.33-5.12, 1.74-19.15, and 2.81-19.27 based on mean drinking water arsenic contents of 283.19, 282.65, and 468.81 microg/L, respectively, in West Bengal, India, Bangladesh, and southwestern Taiwan. Our findings also suggest that increasing urinary monomethylarsonic acid (MMA) levels are associated with an increase in risks of arsenic-induced children skin lesions.     

Arsenic intake via water and food by a population living in an arsenic-affected area of Bangladesh

More and more people in Bangladesh have recently become aware of the risk of drinking arsenic-contaminated groundwater, and have been trying to obtain drinking water from less arsenic-contaminated sources. In this study, arsenic intakes of 18 families living in one block of a rural village in an arsenic-affected district of Bangladesh were evaluated to investigate their actual arsenic intake via food, including from cooking water, and to estimate the contribution of each food category and of drinking water to the total arsenic intake. Water consumption rates were estimated by the self-reporting method. The mean drinking water intake was estimated as about 3 L/d without gender difference. Arsenic intakes from food were evaluated by the duplicate portion sampling method. The duplicated foods from each family were divided into four categories (cooked rice, solid food, cereals for breakfast, and liquid food), and the arsenic concentrations of each food category and of the drinking water were measured. The mean arsenic intake from water and food by all 18 respondents was 0.15 +/-0.11 mg/d (range, 0.043 - 0.49), that by male subjects was 0.18 +/- 0.13 mg/d (n = 12) and that by female subjects was 0.096 +/- 0.007 mg/d (n = 6). The average contributions to the total arsenic intake were, from drinking water, 13%; liquid food, 4.4%; cooked rice, 56%; solid food, 11%; and cereals, 16%. Arsenic intake via drinking water was not high despite the highly contaminated groundwater in the survey area because many families had changed their drinking water sources to less-contaminated ones. Instead, cooked rice contributed most to the daily arsenic intake. Use of contaminated water for cooking by several families was suspected based on comparisons of arsenic concentrations between drinking water and liquid food, and between rice before and after cooking. Detailed investigation suggested that six households used contaminated water for cooking but not drinking, leading to an increase of arsenic intake via arsenic-contaminated cooking water.     

Human exposure to mercury in San Jorge river basin,Colombia (South America)

During May-September 1999 human hair samples were collected from the village of Caimito, a fishing community of the state of Sucre (Colombia), in the San Jorge River basin area, and analyzed for total mercury (t-Hg) by cold vapor atomic absorption spectroscopy. T-Hg was measured in both male and female people aged 15-65 years, whose diet mainly consists of fish collected in nearby marshes. Average hair t-Hg concentration in people from Caimito was 4.91 +/- 0.55 microg/g (n = 94), similar to the value previously detected in fishermen living in the gold mining area, 50 km east. Males had similar t-Hg concentrations (4.31 +/- 0.42 microg/g; n = 56) to females (5.78 +/- 1.21 microg/g; n = 38) and there was no difference in t-Hg levels between groups of different age. Mercury content in hair was weakly but significantly associated (R = 0.20, P = 0.05) with fish consumption.     

Arsenic speciation study in some spring waters of Guam, Western Pacific Ocean

A survey of the different forms of arsenic species: inorganic arsenic (As), As(III), As(V) and organic As(III) and (V) was carried out on spring waters located along Tumon Bay in Guam. The results show that total arsenic concentrations in the spring water samples ranged from <0.3-1.2 microg/L. Inorganic arsenate, As(V), appears to be the dominant species in the spring water samples tested. The concentrations are much lower than previously reported, probably due to a much more rigorous methodological approach and requires further investigations on the status of As contamination in groundwater on the island.     

Application of biological processes for the removal of arsenic from groundwaters

Bacteria are widespread, abundant, geochemically reactive components of aquatic environments. In particular, iron-oxidizing bacteria, are involved in the oxidation and subsequent precipitation of ferrous ions. Due to this property, they have been applied in drinking water treatment processes, in order to accelerate the removal of ferrous iron from groundwaters. Iron also exerts a strong influence on arsenic concentrations in groundwater sources, while iron oxides are efficient adsorbents in arsenic removal processes. In the present study, the removal of arsenic (III and V), during biological iron oxidation has been investigated. The results showed that both inorganic forms of arsenic could be efficiently treated, for the concentration range of interest in drinking water (50-200microg/L). In addition, the oxidation of trivalent arsenic was found to be catalyzed by bacteria, leading to enhanced overall arsenic removal, because arsenic in the form of arsenites cannot be efficiently sorbed onto iron oxides. This method comprises a cost competitive technology, which can find application in treatment of groundwaters with elevated concentrations of iron and arsenic.     

Arsenic and other elements in hair, nails, and skin-scales of arsenic victims in West Bengal, India

For the first time, biological tissues (hair, nails, and skin-scales) of arsenic victims from an arsenic affected area of West Bengal (WB), India were analyzed for trace elements. Analysis was carried out by inductively coupled plasma-mass spectrometry (ICP-MS) for 10 elements (As, Se, Hg, Zn, Pb, Ni, Cd, Mn, Cu, and Fe). A microwave digester was used for digestion of the tissue samples. To validate the method, certified reference materials--human hair (GBW 07601) and bovine muscle (CRM 8414)--were analyzed for all elements. The W test was used to study the normal/log normal distribution for each element in the tissue samples. For hair (n=44) and nails (n=33), all elements show log-normal distribution. For skin-scale samples (n=11), data are not sufficient to provide the information about the trend. Geometric mean, standard error, and range for each element were presented and compared with literature values for other populations. This study reveals the higher levels of toxic elements As, Mn, Pb, and Ni in the tissue samples compared with available values in the literature. The elevated levels of these toxic metals in the tissues may be due to exposure of these elements through drinking water and food. The correlations of Mn and Ni with other essential elements, e.g. Fe, Cu, Zn, suggest that Mn and Ni may substitute for those elements in hair, nails, and skin-scales. However, correlation represents the relation between two elements only and does not take into consideration of the presence of other elements. Principle component analysis was applied to explain the behavior among the elements present in hair and nails. This study reveals that in the arsenic-affected areas of WB, the concentrations of other toxic elements in drinking water and foodstuff should be monitored to evaluate the arsenic poisoning.     

Interaction between chronic arsenic exposure via drinking water and plasma lactate dehydrogenase activity

Arsenic is a potent environmental pollutant that has caused one of the largest public health poisonings in the history of human civilization, affecting tens of millions of people worldwide especially in Bangladesh. Lactate dehydrogenase (LDH) in blood plays an important role in predicting cell or organ damage and as an important clue to the diagnosis of a variety of cancers. However, effect of chronic arsenic exposure on the LDH level in blood has not yet been documented. Since the chronic arsenic exposure is associated with organ damages and multi-site cancers, this research aimed at assaying the plasma level of LDH activity in the population who were exposed to arsenic chronically in Bangladesh. A total of 185 individuals living in arsenic-exposed areas and 121 individuals living in non-exposed area in Bangladesh were recruited as study subjects. Arsenic content in drinking water, hair and nails were estimated by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) and LDH activity was assayed by a spectrophotometer. Significant increase in LDH activity was observed with increasing concentrations of arsenic in water, hair and nails. Further, the study subjects were split into four groups based on the three ways of each exposure metrics (water, hair and nail arsenic concentrations) where the study subjects in the non-exposed area were used as a reference (lowest exposure) group. LDH activity was found to be increased in the higher exposure groups of water and hair arsenic concentrations. LDH activity was also increased at low to medium exposure groups of nail arsenic concentrations.Thus, the elevated plasma LDH activity might be helpful for the early prognosis of organ or tissue damage in the individuals who were exposed to arsenic chronically.     

Treatment of arsenic in Bangladesh well water using a household co-precipitation and filtration system

Laboratory and field tests were conducted to evaluate the effectiveness of a household filtration process and investigate the effects of phosphate and silicate on the removal of arsenic from Bangladesh groundwater by ferric hydroxides. Fe/As ratios of greater than 40 (mg/mg) were required to reduce arsenic to less than 50 microg/L in Bangladesh well water due to the presence of elevated phosphate and silicate concentrations. The household filtration process included co-precipitation of arsenic by adding a packet (approximately 2 g) of ferric and hypochlorite salts to 20 L of well water and subsequent filtration of the water through a bucket sand filter. A field demonstration study was performed to test the treatment system in seven households in Bangladesh in March and April 2000. Experimental results obtained from the participating families proved that the household treatment process removed arsenic from approximately 300 microg/L in the well water to less than 50 microg/L. The participating families liked this simple and affordable process and used it to prepare clean water for drinking and cooking. A larger scale field test is currently underway.