Total tin (TSn) biomagnification: Evaluating organotin trophic flow and dispersion using hepatic TSn concentrations and stable isotope (C, N) data of nektonic organisms from Brazil

A previous investigation of our research team has demonstrated the suitability of using hepatic total tin (Sigma Sn) concentrations for evaluating dolphin exposure to organotins (OTs). The present study develops the previous technique into three different approaches that comprise data: (1) on hepatic Sigma Sn concentrations of 121 Guiana dolphins (Sotalia guianensis) from five different coastal areas (CAs): (2) on Sigma Sn, delta C-13 and delta N-15 for 40 dolphins from Rio de Janeiro state (RJ), including ten different delphinid species; as well as (3) on hepatic Sigma Sn concentrations and delta N-15 values on 31 individuals from five different fish species from Sepetiba Bay (SB, Rio de Janeiro-RJ, Brazil). Hepatic Sigma Sn concentrations of Guiana dolphins from Guanabara Bay (GB, RJ) were significantly higher than those found in other four CAs from S and SE Brazilian regions. Significant positive correlations were found between Sigma Sn concentrations and delta C-13 data in delphinid species, demonstrating a coast-ocean gradient in dolphin exposure to OTs in RI state. Significant and positive correlations were observed between Sigma Sn concentrations and both delta N-15 and Trophic Position (TP) values of fish, as well as high values were found for Tmphic Magnification Factor (TMF = 3.03) and Trophic Magnification Slope (TMS = 0.14), demonstrating OT biomagnification in SB ichthyofauna.