Risk Assessment for Bangladeshis due to Arsenic Exposure from Consumption of Vegetables Grown with Natural Arsenic Contaminated Groundwater

Background/Objectives: In the context of increasing uses of arsenic contaminated groundwater for irrigation in Bangladesh and observed health related problems, we evaluated potential health risk for Bangladeshis due to arsenic exposure from consumption of both aboveground and belowground vegetables. Method/Statistical Analysis: Eight vegetable plants (Amaranth, Arum, Carrot, Eggplant, Indian Spinach, Okra, Potato and Radish) were grown in open field and irrigated with natural as contaminated water (0.005-0.903 mg L^-1) for 80-90 days. We established linear regression equation of fitted model for water–vegetable as concentration (n=54, measured by GF-AAS) relationship. Statistical analyses with r value (0.767), P value (<0.05) of ANOVA table, Durbin-Watson Statistic and Lack-of-Fit test strongly validated the model. Merging British Geological Survey’s groundwater datasets (n=3,534) to the model led to estimation of as contents in vegetables district wise. We followed USEPA Guidelines for Exposure Assessment for evaluation of health risk. Risk, defined as ‘Hazard Quotient’ (HQ), was mapped for three vulnerable population sub-groups: Highly Exposed Child, Average Person and Senior. Findings: The average As concentrations in the vegetables were 0.431, 0.719, 0.928, 1.574 and 2.287 mg kg^-1 (ww.) corresponding to irrigation water as concentrations of 0.005 (control), 0.044, 0.103, 0.507 and 0.903 mg L^-1 respectively. All the Highly Exposed Children (0-6 years) were at health risk, whereas 98% of seniors and 76% of Average Persons (i.e., adults) were safe in consuming vegetables. The eight administrative division wise HQ values for Average Persons were as follows: Rangpur (0.760) < Rajshahi (0.775) < Mymensingh (0.805) < Barisal (0.815) < Sylhet (0.820) < Khulna (0.990) < Dhaka (0.996) < Chittagong (1.147). The worst affected district was Chandpur. Generally the extent of such health risk is less in northern Bangladesh and more in southern Bangladesh. Application/Improvements: This study explored the extent of non-carcinogenic risk for Children (0-6 years), Adults and seniors of Bangladesh from consumption of both aboveground and belowground vegetables. Since the aquifer groundwater of Bangladesh (also contaminated with Co, Mn, Mo, Rb, Sr, U, etc.) is moving under hydraulic gradient, this study highlights the importance of sight-specific risk assessment considering more pollutant parameters.