Arsenic contamination in groundwater and its effects on adolescent intelligence and social competence in Bangladesh with special reference to daily drinking/cooking water intake.

OBJECTIVE: The present study aims to investigate the relationship between arsenic (As) exposure and intelligence quotient (IQ) or social competence (SC) of Bangladeshi adolescents (aged 14 or 15 years) in Sonargaon thana. METHODS: Information about socioeconomic status (SES) was collected as confounding factors. To evaluate the relative contribution of As sources to total As intake, the As concentrations in urine and drinking/cooking water, and the amount of water added in cooking, were assessed on site using a food frequency questionnaire (FFQ). RESULTS: The results confirmed that As exposure was essential to lower adolescent IQ or SC because they were negatively associated with As exposure after controlling for SES (particularly household income). Except for cooking water, the amount of drinking water varied with season and appeared to be the major As source because the As concentration in water was generally correlated with the As concentration in urine, and they were related to lower IQ or SC (even after controlling for SES). The FFQ survey revealed that rice was consumed the most frequently (more than once daily), followed by daal (bean) soup and nonleafy vegetables, but fish, meat, and eggs were consumed approximately once a week. Water intake per meal from cooked rice was estimated to be 616 mL/person, followed by bean soup (258 mL/person) and cooked vegetables (82 mL/person). CONCLUSIONS: Our results suggest that water used for cooking might be an important source of As, and the cooking process can affect the amount of As in cooked food.

A consecutive study on arsenic exposure and intelligence quotient (IQ) of children in Bangladesh.

OBJECTIVE: In a recent cross-sectional investigation, we reported the intellectual function of adolescents (aged 14 and 15 years) in Bangladesh who had been exposed to arsenic (As). Here, we report a consecutive investigation on the intelligence quotient (IQ) of 408 children who are living in the Sonargoan Thana of Bangladesh (two age groups: 9 and 10 years; 4 and 5 years) were exposed to high levels of As in the groundwater. METHODS: Urine and water samples were collected to assess As exposure. The IQ of the children was estimated using the Raven's Standard Progressive Matrices and the Kaufman Brief Intelligence Test. Information on parents' socioeconomic status (SES) was collected as confounding factors. RESULTS: The results indicate that As exposure was responsible for a lower IQ. The concentration of urinary As ([As]u) was associated with reduced intellectual function in a dose-response manner. A stronger association was found between reduced intellectual function (IQ) and [As]u than the level of As in the drinking water [As]w. There was no association between verbal IQ scores and [As]u of children in early childhood (aged 4 and 5 years). CONCLUSION: Based on these results, we conclude that current levels of As in the urine ([As]u), which we considered to reflect recent exposure to As from all possible sources, including groundwater, food, among others, were negatively associated to the IQ of the children tested, and that this adverse effect of As may also gradually accumulate over time among the poor.