Tin and lead compounds in fish and crustacean from aquaculture ponds in Zhejiang Province of East China: Accumulation and health risk assessment

mu Aquaculture industries supply half of the global production, leading to an increasing concern about health risk of the aquaculture products because of widespread distribution of heavy metals in the environment. Considering high dependence of toxicity and bioaccumulation of one metal not merely upon total content but mainly upon its chemical forms, recent investigations into risk assessment of aquaculture products based on total contents of heavy metals may be unreasonable and unfair. In this study, we conducted reasonable assessment to bioaccumulation and health risk of aquaculture fish and crustacean collected from eight aquaculture ponds in Zhejiang Province of East China in terms of chemical forms of two model heavy metals (Sn(II), Pb(II), four organotin compounds, trimethyl lead -TML and triethyl lead -TEL). Although all metal compounds were presented below 0.2-4.1 mu g kg(-1) in aquatic food, they were at moderate contents in environmental matrices following an order of sediment > feedstuff > aquatic food > water for most of the target compounds (i.e. 54-376 mu g kg(-1) Pb(II) in sediment, 14-94 mu g kg(-1) Pb(II) in feedstuff and organotin compounds at pg L-1 levels in water), indicating feedstuff as an important exposure source apart from water adsorption. Bioaccumulation factors, biota-sediment accumulation factors and biomagnification factors demonstrated low bioaccumulation probability although the bioaccumulation level followed an order of organotin and organolead > inorganic forms > total metal. In addition, estimated daily intakes, target hazard quotients and cancer risk demonstrated no health risk for all tin compounds and no carcinogenic risks for all lead compounds but moderate non-carcinogenic risks for TML and TEL. Overall, the accumulation level and health risk were in a closer relationship with the chemical forms of Sn and Pb than their total contents, demonstrating a high necessity to risk assessment in terms of chemical forms.