Title: Assessment of human exposure to toxic elements and veterinary drug residues from seafood consumption in Bangladesh

Background: Seafood from Bangladesh has been reported to be contaminated with toxic elements and residues of forbidden veterinary drugs, although not all types of fish consumed have been analyzed. Estimation of dietary exposure to these chemicals from total seafood intake in the Bangladeshi population would be an important tool in policy planning and mitigation measures.
Aim: To estimate exposure of the Bangladesh population to toxic elements (arsenic, cadmium, lead and mercury) and banned veterinary drug residues (chloramphenicol and nitrofuran metabolites) due to seafood consumption as well as to assess changes in exposure between the years 2010-11 and 2015-16. Also, to evaluate whether the consumption of seafood is a health concern due to presence of these chemicals by comparing the exposure estimates to health-based guidance values (HBGV).
Methods The concentrations of the chemicals in Bangladesh seafood were obtained from National Residue Control Plan (NRCP) samples analyzed in the Quality Control Laboratory of the Department of Fisheries and the Analytical Chemistry Laboratory of the Atomic Energy Centre in Bangladesh. Additionally, the same chemicals were measured in ten hilsa samples which is a popular fish in Bangladesh. Exposure calculations were based on concentration data and the estimated consumption of seafood as drawn from the Household Income and Expenditure Survey of Bangladesh conducted in 2010. Exposure was estimated per capita, male, female and children, for lower-bound (LB) and upper-bound (UB) scenarios.
Results: The highest exposure was observed in children. In 2015-16 the exposure at 50th percentile of this population to arsenic, cadmium, lead and mercury were 0.116, 0.078, 0.302, 0.115 µg/kg bw/week in LB and 1.116, 0.279, 0.829 ,0.408 µg/kg bw/week in UB estimates, respectively. However, exposure at 95th percentile of the same population to these chemicals were 0.453, 0.234, 2.855, 0.480 µg/kg bw/week in LB and 2.757, 1.082, 3.518, 0.965 µg/kg bw/week in UB estimates, respectively. The exposure of children to chloramphenicol was zero and to the nitrofuran metabolites were very low. Exposure estimates for all chemicals investigated were below the HBGV set for full dietary intake.
Conclusions: The exposure estimates for seafood do not raise a health concern for any of the chemicals investigated. Exposure to chloramphenicol and nitrofuran metabolites was lower in 2015-16 compared to 2010-11, while exposure to arsenic, cadmium and mercury increased. Lead concentration was high in the hilsa samples and 50% of the samples exceeded the EU maximum limits for content in fish for consumption. However, the number of hilsa samples investigated was small and the results need to be confirmed by further studies.