**3.1 Bioaccumulation factor**

The bioaccumulation factor for aquatic species was tested [33]. The ratio between metal concentrations in organism to that of environment is referred as bioaccumulation factor. When metal concentrations in organism exceed those in aquatic environment this is referred as bioaccumulation. Thus, the bioaccumulation is recognized for value lower than 1.

> metal concentration in organism Bioaccumulation factor = metal concentration in sediment
