Spot urine samples were collected from the inhabitants of two rural communities in northwestern Bangladesh. We compared arsenic levels in the urine samples ([As](u); n = 346) with those in water from tube wells ([As](tw); range < 1-535 microg/L; n = 86) on an individual basis. The small variation of [As](u) within subjects and highly positive correlation with [As](tw) indicate that [As](u) is a useful indicator of exposure. Analyses of [As](u) showed that creatinine correction was necessary, that [As](u) only reflected recent exposure, and that there were substantial interindividual differences for a given [As](tw) level. To evaluate the toxic effects of arsenic exposure, we constructed a system for rating skin manifestations, which revealed distinct sex-related differences. Comparison of males and females in the same households confirmed that skin manifestations were more severe in the males, and in the males of one community a dose-response relationship between [As](u) and the degree of skin manifestation was evident. The results of this study indicate that [As](u) in spot urine samples can be used as an exposure indicator for As. They suggest that there might be sex-related, and perhaps community-related, differences in the relationship between [As](u) and skin manifestations, although several confounding factors, including sunlight exposure and smoking habits, might contribute to the observed sex difference. The existence of such differences should be further confirmed and examined in other populations to identify the subpopulations sensitive to chronic arsenic toxicity.
Large-scale human exposure to arsenic through contaminated groundwater is a serious health threat in many Asian and Latin American countries. With the exception of a series of studies in Taiwan (1-5), attention has only recently been given to the epidemiological and human toxicological aspects of this contamination. The tube wells that provide drinking water in rural Bangladesh are contaminated with geologically derived arsenic (6). Consumption of the contaminated water is a likely cause of skin conditions such as keratosis and melanosis, which are sensitive manifestations of chronic arsenic toxicity, in many members of these communities. In this paper, we describe the doseresponse relationship of chronic arsenic exposure and skin problems in rural Bangladeshi communities. Two methodologic features distinguish this investigation from other recently published reports of the arsenic problem in Bangladesh and the nearby region of West Bengal, India (7-13). First, the selected indicator of dose/exposure is urinary arsenic concentration ([As] u). This contrasts with other studies that relied on the arsenic concentration in the water from tube wells ([As] tw) (14,15), or indices derived from it (9,12), as the dose/exposure indicator.
While many reports have outlined the health risk of chronic arsenic exposure on adult populations, relatively little is known about the effects on children. We have examined the effects of chronic arsenic exposure through consumption of contaminated groundwater among 241 children (age 4-15 yr) living in two rural villages in northern Bangladesh. The arsenic concentrations of the tubewell waters ranged from less than detection limit to 535 ng/mL, and in 72 of 241 (30%) tubewells, the water arsenic concentration exceeded 50 ng/mL, the provisional guideline of Bangladesh. Approximately half of the examined children exhibited dermatological symptoms with relatively obscured dose-response relationship; an observation suggesting that the children were no more susceptible to the dermatological effects of arsenic than the adults living in the same communities. Proportion of the children with lower BMI significantly increased with increasing arsenic exposure level; the dose-response relationship was consistently observed among the subgroups. These results suggested that while mild dermatological manifestations, potentially associated with arsenic exposure, could be found as much as half of the children, nutritional status of the children, evaluated by BMI, might be a sensitive endpoint than the dermatological manifestations among children in this area.
Toxicological and metabolic interactions of selenium (Se) with arsenic (As) have been reported in many experimental studies. However, for human populations, possible interactions between As and Se and their toxicological significance have not been established. In this study, we have examined the relationship between Se and As in spot urine samples collected from the inhabitants of two rural communities of northeast Bangladesh. The urinary As (U As ) and Se (U Se ) concentrations were determined by hydride generation atomic absorption spectrometry (HGAAS). Negative correlation between U As and U Se was found in both males and females. Considering the exposure condition in these communities, it is unlikely that the correlation reflected the correlation between the intakes of these elements. This result suggests that As exposure from drinking water or food may change Se metabolism in humans. Possible toxicological significance of the interaction is discussed.
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