Evaluation of trace metals (cadmium, chromium, copper and zinc) in tissues of a commercially important fish (Leporinus obtusidens) from Guaíba Lake, Southern Brazil

Abstract

Concentrations of Cd, Cr, Cu and Zn were determined in liver and muscle of Leporinus obtusidens. During 2003, the fishes (N = 54) were sampled from three sites along Guaíba Lake (north, central and south zones). The hypotheses tested assumed that there were differences in the location and date as to levels of contamination, association between the trace metal content in the fishes and size, and that the sex influenced metal accumulation. Possible risks of contaminated fish consumption to human health were also evaluated. The level of mean concentration (µg/g) of metals in tissues was higher in liver than muscle: [Cd] = 2.32♂; [Cr] = 0.08♀; [Cu] = 30.82♀ and [Zn] = 97.77♀. The results showed differences between the local and date sampling for all metals except Cr. Metal content was higher in the warmer than colder seasons and in the central zone than at other points. Significant sexual differences were detected for Cd and Zn and there were positive associations between the size and metal concentrations for Cu and Zn. The concentration levels of metals in muscle tissue showed that the fish samples did not offer risks to human health.