Sources and trophic transfer of trace metals in wild fish from coastal areas in the South China Sea

Abstract

Context Wild fish is a good source of minerals and other high-quality nutrition; however, many wild fish species potentially accumulate hazardous metals, making them a threat to human health. Aims The aim was to study characteristics and the source of metals in wild fish in the South China Sea by using, for the first time, the correlation of trace metals and stable isotopes. Methods Analytical instruments and statistical methods were respectively used to determine elements and the relative correlations. Key results Lead (Pb) and manganese (Mn) tended to accumulate in bluespot mullet and Macao tonguesole. Variation among fish species and spatial differences might be two important factors influencing both the metal concentrations and the selenium (Se):mercury (Hg) molar ratios in biota. Hg, Mn, Pb and tin (Sn) tended to be biomagnified with an increasing trophic level, whereas chromium (Cr) and copper (Cu) showed a trend of biodilution. Conclusions The Se:Hg molar ratios exhibited noticeable species and spatial variation for the wild fish, whereas the main sources of Sn and Pb contamination might be antifouling reagents and surface applications. Implications The speciation of the elements is worth investigating next, so as to obtain valuable insight into the state of the wild environment and the impacts to human wellbeing.