Trophic transfer of heavy metals in a wetland food web from an abandoned e-waste recycling site in South China

In order to understand the pollution status and trophic transfer of heavy metals across wetland food web organisms, four invertebrate species, six fish species, one snake species, and one bird species were collected from an abandoned e-waste site in South China for analysis of toxic elements (Ni, Zn, Cu, Cr, Cd, and Pb). The concentrations of Ni, Zn, Cu, Cr, Cd, and Pb were 0.16-15.6, 24.9-850, 1.49-645, 0.11-64.6, 0.01-4.53 and 0.41-40.4 mg/kg dry weight, respectively. The results demonstrated that the concentrations of six studied heavy metals decreased throughout the whole food web, but Cu and Zn concentrations increased along the bird and reptile food chains, respectively. The trophic transfer of metals for the key species should be of special attention, as the trophic biomagnification factor (TMF) in a food web may overlook the ecological risks of metals for certain species, especially those at high trophic levels. The estimated daily intake (EDI) and the target hazard quotient (THQ) results showed that Cu, Cd, and Pb posed the main risks on human health, especially through the consumption of snail and crab species.