Heavy metals (Co, Ni, Cr, Pb, Cd) content in tissues of Nitra river fishes

Abstract

In this study the heavy metal (Co, Ni, Cr, Pb, Cd) content in muscle, liver and kidney of totally 53 fish individuals, belonging to eight species (chub Leuciscus cephalus, common carp Cyprinus carpio, Prussian carp Carassius gibelio, common bream Abramis brama, sneep Chondrostoma nasus, European perch Perca fluviatilis, zander Sander lucioperca and Wels catfish Silurus glanis) was determined. The samples were collected from the river Nitra at 53th–54th r.km (in the city district Nitra–Krškany) in September 2003. Samples of fish muscle, liver and kidney were obtained at weight 2–3 g (in the case of European perch three samples of kidney were merged together, due to a small quantity of tissue). Heavy metal contents in the fish tissues were analysed by an atomic absorption spectrophotometer (AAS) using nitrid acid HNO3 (results are presented in milligram per kilogram wet weight basis). For statistical analysis, the anova one-way test, Kruskal–Wallis test and Kolmogorov–Smirnov two-sample test were used with computer program Statgraphics Plus version 5.1. In the selected tissues following concentrations of monitored metals were detected: muscle liver kidney Co 0.07 – 0.24 0.03 – 0.87 0.08 – 2.16 Ni 0.06 – 0.19 0.00 – 0.85 0.08 – 0.83 Cr 0.03 – 0.13 0.07 – 0.51 0.00 – 0.51 Pb 0.11 – 0.59 0.00 – 1.29 0.00 – 2.15 Cd 0.03 – 0.30 0.03 – 0.58 0.00 – 6.79 Monitored metals in the majority of cases are cumulated in kidney and liver, then in muscle, as follows: Co kidney > liver > muscle Ni kidney > muscle > liver Cr liver > kidney > muscle Pb kidney > muscle > liver Cd kidney > liver > muscle Significant differences between metals accumulation in tissues of predatory and non–predatory fish species were observed (without cobalt, nickel, lead and cadmium in liver, as well as nickel, chromium, lead and cadmium in kidney). Non-predatory fish species contain significantly more cobalt, nickel, chromium, lead and cadmium in muscle, chromium in liver, as well as cobalt in kidney.