Lead, Cadmium, Gastropod, Bivalve, Metal gradient, Zinc, Metals - pharmacokinetics, Metals - analysis, Mytilidae - drug effects, Water Pollutants, Chemical - pharmacokinetics, Biological Availability, Gastrointestinal Tract - drug effects, Gills - chemistry, Metals - toxicity, Tissue Distribution, Gills - drug effects, Animals, Water Pollutants, Chemical - t...