Effect of Safe Water on Arsenicosis: A Follow-up Study.

BACKGROUND: Arsenic pollution in groundwater, used for drinking purposes, has been envisaged as a problem of global concern. Treatment options for the management symptoms of chronic arsenicosis are limited. Mitigation option available for dealing with the health problem of ground water arsenic contamination rests mainly on supply of arsenic safe water in arsenic-endemic region of Indo-Bangladesh subcontinent. Limited information is available regarding the long-term effect of chronic arsenic toxicity after stoppage of consumption of arsenic-containing water. OBJECTIVE: The current study was, therefore, done to assess, objectively, the effect of drinking arsenic safe water (<50 µg/L) on disease manifestation of arsenicosis. RESULTS: Manifestations of various skin lesions and systemic diseases associated with chronic arsenic exposure were ascertained initially by carrying on baseline study on 208 participants in Nadia (Cohort-I, with skin lesion and Cohort-II, without skin lesion) using a scoring system, as developed by us, and compared objectively at the end of each year for 3 year follow-up period. All the participants who had arsenic contaminated drinking water source in their houses were supplied with arsenic removal filters for getting arsenic-free water during the follow-up period. In participants belonging to Cohort-I, the skin score was found to improve significantly at the end of each year, and it was found to be reduced significantly from 2.17 ± 1.09 to 1.23 ± 1.17; P < 0.001 at the end of 3 year's intervention study indicating beneficial effect of safe water on skin lesions. The systemic disease symptom score was also found to improve, but less significantly, at the end of 3 years in both the cohorts. Most important observation during the follow-up study was persistence of severe symptoms of chronic lung disease and severe skin lesion including Bowen's disease in spite of taking arsenic-safe water. Further, death could not be prevented to occur because of lung cancer and severe lung disease. CONCLUSION: It is, therefore, an urgent need to make arrangement for availability of safe water source among the arsenic-affected people in the district. Many of the people in the affected villages are not aware of contamination of their home tube wells with arsenic. Awareness generation and motivation of the people for testing their drinking water sources for arsenic and environmental interventions like rain water harvesting, ground water recharge, and restricting excessive use of ground water for domestic and agricultural purposes are also important to prevent further exposure of arsenic to these people.

Seasonal perspective of dietary arsenic consumption and urine arsenic in an endemic population.

Exposure to arsenic in arsenic endemic areas is most remarkable environmental health challenges. Although effects of arsenic contamination are well established, reports are unavailable on probable seasonal variation due to changes of food habit depending on winter and summer seasons, especially for endemic regions of Nadia district, West Bengal. Complete 24-h diets, drinking-cooking water, first morning voided urine samples, and diet history were analyzed on 25 volunteers in arsenic endemic Chakdah block of Nadia district, once in summer followed by once in winter from the same participants. Results depicted no seasonal variation of body weight and body mass index. Arsenic concentration of source drinking and cooking water decreased (p = 0.04) from 26 µg L(-1) in summer to 6 µg L(-1) in winter season. We recorded a seasonal decrease of water intake in male (3.8 and 2.5 L day (-1)) and female (2.6 and 1.2 L day(-1)) participants from summer to winter. Arsenic intake through drinking water decreased (p = 0.04) in winter (29 µg day(-1)) than in summer (100 µg day(-1)), and urinary arsenic concentration decreased (p = 0.018) in winter (41 µg L(-1)) than in summer (69 µg L(-1)). Dietary arsenic intake remained unchanged (p = 0.24) over the seasons. Hence, we can infer that human health risk assessment from arsenic needs an insight over temporal scale.

Dietary arsenic exposure with low level of arsenic in drinking water and biomarker: a study in West Bengal.

The authors investigated association of arsenic intake through water and diet and arsenic level in urine in people living in arsenic endemic region in West Bengal supplied with arsenic-safe water (<50 µg L(-1)). Out of 94 (Group-1A) study participants using water with arsenic level <50 µg L(-1), 72 participants (Group-1B) were taking water with arsenic level <10 µg L(-1). Multiple regressions analysis conducted on the Group-1A participants showed that daily arsenic dose from water and diet were found to be significantly positively associated with urinary arsenic level. However, daily arsenic dose from diet was found to be significantly positively associated with urinary arsenic level in Group-1B participants only, but no significant association was found with arsenic dose from water in this group. In a separate analysis, out of 68 participants with arsenic exposure through diet only, urinary arsenic concentration was found to correlate positively (r = 0.573) with dietary arsenic in 45 participants with skin lesion while this correlation was insignificant (r = 0.007) in 23 participants without skin lesion. Our study suggested that dietary arsenic intake was a potential pathway of arsenic exposure even where arsenic intake through water was reduced significantly in arsenic endemic region in West Bengal. Observation of variation in urinary arsenic excretion in arsenic-exposed subjects with and without skin lesion needed further study.

Dietary arsenic consumption and urine arsenic in an endemic population: response to improvement of drinking water quality in a 2-year consecutive study.

We assessed the association between arsenic intake through water and diet, and arsenic levels in first morning-void urine under variable conditions of water contamination. This was done in a 2-year consecutive study in an endemic population. Exposure of arsenic through water and diet was assessed for participants using arsenic-contaminated water (≥50 µg L(-1)) in a first year (group I) and for participants using water lower in arsenic (<50 µg L(-1)) in the next year (group II). Participants with and without arsenical skin lesions were considered in the statistical analysis. Median dose of arsenic intake through drinking water in groups I and II males was 7.44 and 0.85 µg kg body wt.(-1) day(-1) (p <0.0001). In females, it was 5.3 and 0.63 µg kg body wt.(-1) day(-1) (p <0.0001) for groups I and II, respectively. Arsenic dose through diet was 3.3 and 2.6 µg kg body wt.(-1) day(-1) (p = 0.088) in males and 2.6 and 1.9 µg kg body wt.(-1) day(-1) (p = 0.0081) in females. Median arsenic levels in urine of groups I and II males were 124 and 61 µg L(-1) (p = 0.052) and in females 130 and 52 µg L(-1) (p = 0.0001), respectively. When arsenic levels in the water were reduced to below 50 µg L(-1) (Indian permissible limit), total arsenic intake and arsenic intake through the water significantly decreased, but arsenic uptake through the diet was found to be not significantly affected. Moreover, it was found that drinking water mainly contributed to variations in urine arsenic concentrations. However, differences between male and female participants also indicate that not only arsenic uptake, but also many physiological factors affect arsenic behavior in the body and its excretion. As total median arsenic exposure still often exceeded 3.0 µg kg body wt.(-1) day(-1) (the permissible lower limit established by the Joint Expert Committee on Food Additives) after installation of the drinking water filters, it can be concluded that supplying the filtered water only may not be sufficient to minimize arsenic availability for an already endemic population.

Evaluation of dietary arsenic exposure and its biomarkers: a case study of West Bengal, India.

Few reports are available that characterize daily arsenic exposure through water and diet among people living in groundwater-contaminated regions and correlate it with biomarkers. The present study describes the total individual arsenic exposure and arsenic level in urine and hair of such an arsenic-exposed population in West Bengal. Demographic characteristics and the total daily arsenic intake through water and diet were determined in 167 (Group-1 participants selected from arsenic endemic region) and 69 (Group-2 participants selected from arsenic non-endemic region) in West Bengal. Out of 167 Group-1 participants 78 (Group-1A) had arsenical skin lesions while 89 Group-1B) had no such lesion. Arsenic level in water samples as well as diet, urine and hair samples, collected from all the individual participants, were estimated. The mean value of estimated total arsenic content from water and diet was 349 (range: 20-1615) µg/day in 167 (Group-1) participants living in As endemic region [As in water: mean value 54 (range:BDL-326) µg/L] and 36 (range:12-120) µg/day in 69 (Group-2) participants living in As non-endemic region (As in water: below detection level (BDL), < 0.3 µg/L). Estimated mean arsenic level in urine in these two groups of participants was 116 (range: 6-526) µg/L and 17 (range: BDL-37) µg/L and in hair was 1.0 (range: 0.22-3.98) mg/Kg and 0.16 (range: 0.06-0.37) mg/Kg, respectively. Multiple regressions analysis in Group-1 participants showed that total arsenic intake was associated significantly with urinary and hair arsenic level. The estimated regression coefficient was 0.0022 (95% confidence interval, C.I: 0.0016, 0.0028; P < 0.001) and 0.0024 (95% C.I: 0.0021, 0.003; P < 0.001), respectively. In sub group analysis, higher median urinary arsenic value relative to arsenic intake through water and diet was observed in 78 Group-1A subjects with skin lesion compared to urinary arsenic value in 89 Group-1B subjects without skin lesions, though there was a marginal difference of median total arsenic intake in these two groups. This study showed that significant elevation of arsenic level in urine and hair was associated with elevated arsenic intake through water and diet in people living in arsenic endemic region (Group-1), while these values were low in people living in non-endemic region (Group-2). Those with skin lesions were found to have higher arsenic in urine and hair compared to those without skin lesion with similar arsenic intake through water and diet.

Nutritional deficiency and arsenical manifestations: a perspective study in an arsenic-endemic region of West Bengal, India.

OBJECTIVE: To assess whether nutritional deficiency increases susceptibility to arsenic-related health effects. DESIGN: Assessment of nutrition was based on a 24 h recall method of all dietary constituents. SETTING: Epidemiological cross-sectional study was conducted in an arsenic endemic area of West Bengal with groundwater arsenic contamination. SUBJECTS: The study was composed of two groups ­ Group 1 (cases, n 108) exhibiting skin lesions and Group 2 (exposed controls, n 100) not exhibiting skin lesions ­ age- and sex-matched and having similar arsenic exposure through drinking water and arsenic levels in urine and hair. RESULTS: Both groups belonged to low socio-economic strata (Group 1 significantly poorer, P<0·01) and had low BMI (prevalence of BMI<18·5 kg/m2: in 38% in Group 1 and 27% in Group 2). Energy intake was below the Recommended Daily Allowance (set by the Indian Council of Medical Research) in males and females in both groups. Increased risk of arsenical skin lesions was found for those in the lowest quintile of protein intake (v. highest quintile: OR=4·60, 95% CI 1·36, 15·50 in males; OR=5·62, 95% CI 1·19, 34·57 in females). Significantly lower intakes of energy, protein, thiamin, niacin, Mg, Zn and choline were observed in both males and females of Group 1 compared with Group 2. Significantly lower intakes of carbohydrate, riboflavin, niacin and Cu were also observed in female cases with skin lesions compared with non-cases. CONCLUSIONS: Deficiencies of Zn, Mg and Cu, in addition to protein, B vitamins and choline, are found to be associated with arsenical skin lesions in West Bengal.

Hypertension in chronic arsenic exposure: A case control study in West Bengal.

Various systemic manifestations are reported to be caused by chronic arsenic exposure in the population living in the Indo-Bangladesh subcontinent. This study from West Bengal assesses the likelihood of occurrence of hypertension (HTN) in individuals resident in an area of high groundwater contamination with arsenic (Nadia district) compared to those from a non-contaminated area (Hoogly district) in West Bengal, India. Two hundred and eight study participants (Group 1) were recruited from a cross-sectional study in six villages in the Nadia district and 100 controls (Group 2) from a village in the Hoogly district. The two groups were evenly matched in regard to age and sex. History taking and clinical examination including blood pressure measurement were undertaken in each participant. Water samples from current and previous drinking water sources and hair and urine samples from each participant were collected for estimation of arsenic. The present study shows evidence of increased association of HTN in individuals resident in arsenic endemic region compared to those from a non-endemic region in West Bengal. There were increased odds ratios for HTN [Adjusted Odds Ratio, OR, 2.87 (95 %CI = 1.26-4.83)] in Group- 1 participants compared to Group- 2 people. Within Group 1, there was no difference in prevalence of HTN between those with and without skin lesion. There was a dose-effect relationship seen with increasing cumulative arsenic exposure and arsenic level in hair and HTN in participants living in arsenic endemic region.The findings reported here support an association between arsenic exposure and HTN. More work is needed to characterize the link further.