BIOACCUMULATION OF 18 TRACE METALS IN MUSCLE AND EXOSKELETON IN THE NOBLE CRAYFISH (ASTACUS ASTACUS L.) IN THE RIVER ZETA (MONTENEGRO)

This study assessed the level of heavy metals accumulation in abdominal muscle and exoskeleton on of Astacus astacus L. collected from Zeta River in July, with the aim of predicting health risk effect on human consumers. Noble crayfish samples were collected from four different sites along the river. The concentration of metals in the muscle and chitin of the Noble crayfish was determined using atomic absorption spectrophotometer. The exoskeleton showed a decidedly higher content of most analysed trace elements with respect to muscles (two- to fourfold higher for Al, Ca; two-to eightfold for Fe and ten times higher for Sn and Mn). Hg, K, Mg and Zn were found in higher concentrations in the abdominal muscle in Noble crayfish from the River Zeta. Nonsignificant differences were found between muscles and exoskeleton for As, Cu, K, Na, Ni, and Si (except first locality). Muscle content analysis had indicated that sampling point I (first) had the lowest concentration and sampling point IV (the last) had the highest concentration of accumulated heavy metals. It was believed that domestic activities around the river the major contributing factor to the accumulation of toxic heavy metals in muscle and carapace sample analysed, it is recommended that intervention relevant authorities are needed to curtail chemical degradation of the aquatic biota over a period of time. The most of trace element concentrations found in crayfish tissues were in the range considered harmful to human health (except for Na, Ni, Sn and Cr). We hypothesize that A. astacus in the Zeta River aquatic communities can act as a vector of pollutants, as crayfish can transfer their relatively high amount of heavy metals to higher trophic levels.