Bioenrichment of potentially toxic elements in fishes and shrimps of Sepetiba Bay (RJ, SE Brazil)

Abstract

The main objectives of this study are to analyze the presence of potentially toxic chemical elements (PTEs) in fish and shrimp from Sepetiba Bay (coastal region of the State of Rio de Janeiro, SE Brazil), compared to results obtained in previous studies and to discuss the risks of consuming contaminated food for humans. Sepetiba Bay is a coastal system heavily contaminated by PTEs. Concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, Se, and Zn were analyzed in tissues and organs of crustaceans (shrimp, Farfantepenaeus subtilis) and bony fishes (Cynoscion leiarchus, Cynoscion acoupa, Centropomus undecimalis, Plagioscion squamosissimus, Selene setapinnis, and Caranx hippos) using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Copper was the element that reached the highest levels among the analyzed species/tissues/organs, followed by Zn > Se > As>Cd > Pb > Cr > Ni > Co. Still, Zn, Cu, and Cr were present in all analyzed samples. For most species, the organs with the highest levels of PTEs were the heart and liver. The statistical results showed positive and significant correlations between the PTE concentrations of the analyzed species/tissues/organs. The Bioenrichment Factors (BF: the ratio between the levels of PTEs in the analyzed tissues/organs and the limits defined by the regulatory agencies) show that there are higher levels of PTEs than those allowed by law in the analyzed species/tissues/organs (descending order number of times higher): Cr (71), Se (35), Pb (32), Cu (23), As (13), Cd (10), Zn (7), and Co (5). For example, Cr showed relatively high BF values: C. acoupa (heart: 70 times; gills 9 times), C. undecimalis (heart 17 times), C. leiarchus (gills 13 times; heart 11 times; liver 9 times); gonads 8 times), C. undecimalis (gills 12 times), P. squamosissimus (gills 10 times) and F. subtilis (cephalothorax 9 times; carapace 7 times; muscle 7 times). The heart of S. setapinnis (35 times), the liver of P. squamosissimus (23 times), and the muscle of F. subtilis (4 times) showed Se enrichment higher than the amount authorized by Brazilian legislation (Anvisa). The gills of P. squamosissimus (32 times) and the gonads of C. leiarchus (5 times) and C. acoupa (4 times) indicated considerable bioaccumulation values for Pb enrichment, above the FAO/WHO (Food and Agriculture Organization/World Health Organization) limit. Therefore, this study shows a potential risk of metal contamination in the population that eats fish in the Sepetiba region. Fish is part of the traditional diet of the population living around Sepetiba Bay, primarily among low-income families who dominate the area. The results of this study suggest the need to monitor seafood contamination in this region.