Heavy metal accumulation in fishes of different ecological groups from Kairiai landfill regional aquatic ecosystem

Abstract

The main purpose of this study was to determine heavy metal (HM) accumulation in body tissues (gills, liver and muscle) of different ecological group fishes [bentophagous (gibel carp and roach) and predatory (pike and perch)] from Kairiai landfill regional aquatic ecosystem. Test fish were collected during experimental fishing. Heavy metal analysis was performed in accordance with ISO 11047:2004, and Hg analysis - according to ISO 16772:2004 standard procedures. The following HMs were found in fish body tissues: Cr, Cu, Ni, Zn and Hg, while Pb and Cd content was below the instrument detection limit. The highest amounts were found of Zn, while the lowest of Ni. Nickel and Cr concentration in bentophagous and liver and muscle as well as Zn and Cu concentration in the gills and liver of predatory fish (in mg/kg of raw mass) exceeded Lithuanian hygiene standard [maximum-allowable-amount (MAA)] for human consumption. Correlation (Pearson r) between HM content and their concentration in water and bottom sediments as well as various physico-chemical parameters have been also investigated. Very strong and averagely strong relationship has been established between Ni content in bentophagous fish liver and HM concentration in the water and bottom sediments as well as Cl¯, HCO3¯, Na+, K+, NH4+; between Zn content in predatory fish gills and Cl¯, HCO3¯, Na+, K+, NH4+, Mg2+; between Cr content in bentophagous fish liver and HM concentration in the water as well as Cl¯, HCO3¯, Na+, K+, NH4+, Mg2+, CO2; between Cu content in bentophagous gills and HM concentration in the bottom sediments, and weak relationship between Hg content in both bentophagous and predatory fish tissues and HM concentration in the water, bottom sediments as well as other physico-chemical parameters. Summarizing the obtained results it could be concluded that Kairiai landfill still remains a serious source of permanent environmental pollution, although it is already closed.