Mercury and methylmercury content, fatty acids profile, and proximate composition of consumed fish in Cananéia, São Paulo, Brazil

Abstract

Fifty three individuals of four most commonly consumed fi sh species by the Cananéia city population, in São Paulo, Brazil, were analyzed to determine total mercury (Total Hg) and methylmercury (MeHg) levels, as well as, proximate composition and fatty acid profi le. The muscle of three carnivorous species Centropomus parallelus (Fat snook), Macrodon ancylodon (King weakfi sh) and Micropogonias furnieri (Whitemouth croaker), and one planktivorous species Mugil platanus (Mullet) were analyzed. MeHg and Total Hg determinations were performed by Cold Vapour Atomic Absorption Spectrometry (CV AAS). Fatty acid profi le was determined by gas chromatography (GC) whilst AOAC methods were used for proximate analysis. The total Hg results (interval) in wet weight basis were: Whitemouth croaker (114–442 μg kg-1), Fat snook (15-178 μg kg-1), King weakfi sh (12-100 μg kg-1) and Mullet (<10–25 μg kg-1), and none of the fi sh species exceeded the Brazilian legislation limits. MeHg values were below FAO/WHO (2007) recommendations. In nutritional terms, the results for proximate composition for all four fi sh species proved to be an excellent protein source with very low lipid content as was expected. Fatty acids of all fi sh species were adequate. Total polyunsaturated fatty acid contents varied from 21.9% (Micropogonias furnieri) to 26.4% (Mugil platanus). For the n-3 family, Macrodon ancylodon presented the highest value (20.9%) and Micropogonias furnieri the lowest one (15.8%). Mugil platanus (Mullet) species also showed good levels for all parameters analyzed and very low concentrations of contaminants, indicating it as a good nutritional choice in terms of risks and benefi ts.