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.

The prevalence of arsenicosis was quite high and males were more vulnerable to arsenic contamination. Using skin manifestations, especially keratosis on the soles, as useful markers to detect and evaluate arsenicosis, it is clear that there is an urgent need to assess the exact prevalence and severity of arsenicosis in the population of Bangladesh in order to take measures to treat and control this problem.

Two surveys, one in winter the other in summer time, examined the skin problems of the entire manual workers (N=148) from 11 small-to-medium sized fiber-glass reinforced plastics (FRP) factories located in Kyushu, Japan. The workers were exposed to unsaturated polyester resin, including styrene and auxiliary agents such as cobalt naphthenate, hardeners such as methyl ethyl ketone peroxides, glass fiber and dust including shortened glass fiber and plastic particles. Eightyseven workers (58.8%) reported having skin problems (mainly itching or dermatitis) since they started to work in FRP manufacturing and 25 workers had consulted a physician because of their skin problems; one worker was forced to take sick leave because of his severe dermatitis. History of allergic diseases and shorter occupational period (duration of employment) in a FRP factory were associated with greater probability of having a history of work-related skin symptoms. Workers in factories where dust-generating and lamination sites were located in different buildings were significantly less likely to have a history of skin problems than those in factories where the two sites were located in the same building. Of the 67 workers examined in both seasons closed to double the prevalence of dermatitis was found in summer (23.3%) than winter (13.4%).

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.