Assessment of adaptation capability of the bivalves<i> Modiolus modiolus</i> (Linnaeus, 1758) and<i> Crenomytilus grayanus</i> (Dunker, 1853) under increased levels of heavy metals in the environment
The active biomonitoring method was used to examine the change in heavy metal (Fe, Zn, Cu, Cd, Mn, Pb, Ni) contents in organs (muscle, gonads, mantle, gills, digestive gland, kidney) of the bivalves Crenomytilus grayanus and Modiolus modiolus. The dynamics of concentration of trace elements in organs of mollusks during the experiment was compared with their subcellular distribution. The defense strategy of M. modiolus consisted in threshold accumulation of toxic metals in all organs followed by their excretion, whereas the strategy of C. grayanus involved a short-term isolation from adverse environmental influence. In C. grayanus, under chronic pollution, the digestive gland and kidney experienced the greatest toxic effect. At acute changes in environmental conditions, the processes of regulation (detoxification/excretion) of Fe, Mn, and Pb in this species were impaired substantially.