Transference of heavy metals (Hg, Cu, Pb and Zn) with the trophic structure in a polyculture pond: evidence from nitrogen stable isotope

Concentrations of heavy metals, including Hg, Cu, Pb and Zn, in sediment and different organisms as well as the transference through the food web in a polyculture pond were investigated. The δ15N values of consumers showed a gradual enrichment with increasing trophic positions from the filter‐feeding bivalves (δ15N = 10.93 on average) to the predators (δ15N ≥ 12.59 for all crustacean and fish). Concentrations of heavy metals in sediments followed the decreasing order: Cu ≈ Zn > Pb > Hg, while in organisms, the order was Zn > Cu > Pb > Hg. Concentration of Cu was negatively related to the δ15N values of the animal tissues (P