Concentration of selected metals in muscle of various fish species

The purpose of this study was to assess concentration of selected metals (Fe, Mn, Zn, Cu, Ni, Co, Cr, Pb, Cd, and Hg) in the muscle of four common Slovak fish species (chub--Leuciscus cephalus, barbel--Barbus barbus, roach--Rutilus rutilus, and perch--Perca fluviatilis). Furthermore, correlations among the selected metals and order of metal accumulation in the fish muscle were determined. An electrofishing technique was used for collecting the fish from the Nitra River (Slovakia) in September 2003. Concentrations of selected metals were measured using an atomic absorption spectrophotometer Pye Unicam SP9. The concentrations of metals (mg/kg wet weight basis) ranged as follows: Fe 3.41-15.14; Mn 0.20-0.81; Zn 3.51-15.64; Cu 0.25-0.78; Ni 0.07-0.25; Co 0.05-0.19; Cr 0.11-0.42; Pb 0.20-5.81; Cd 0.06-0.56, and Hg 1.35-6.52. Significant correlations (P < 0.05) between Fe-Cu, Fe-Ni, Fe-Cr, Mn-Ni, Mn-Cr, Mn-Cr, Cu-Ni, and Ni-Cr were observed. The level of lead exceeded the maximum allowable concentration in Slovakia by Codex Alimentarius for safe human consumption (0.2 mg/kg) in the majority of samples (97.2%). Content of Cd (0.23 +/- 0.13 mg/kg wet weight) and Hg (2.85 +/- 1.22 mg/kg wet weight) in the fish muscle exceeded maximum allowed levels in all samples. On average, the order of metal concentrations in the fish muscle was: Fe > Zn > Hg > Pb > Cu > Mn > Cd > Cr > Ni > Co.