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.