In this paper we studied the bioaccumulation of heavy metals in red
swamp crayfish populations from sites of very different levels of environmental
contamination. The selective bioaccumulation of these contaminants
in the hepatopancreas tissues (important organ of
detoxification) and in the abdominal muscle (edible part of the crayfish)
was clearly related to low or high level of pollution sites.
The proposed Toxic Contamination Index allowed to assess the toxicity
by heavy metals of the freshwater sediments through top-down
approach, measuring the stress level of the detoxification organ of the
crayfish. In fact, TCI formulation dependent only on metal bioaccumulation
data of hepatopancreas and abdominal muscle of the bioindicator
(i.e. P. clarkii) and therefore is particularly easy to be determined. In addition,
TCI is a useful tool, as biological response, in the environmental management to assess the effectiveness of the restoration of contaminated
sites.