Metals, Heavy - metabolism, Mutagens - metabolism, Mutagens - toxicity, Zinc - metabolism, Eels - blood, Fresh Water - chemistry, Cadmium - metabolism, Mercury - metabolism, Micronucleus Tests, Kidney - metabolism, Zinc - analysis, Liver - drug effects, Copper - metabolism, Geologic Sediments - chemistry, Metals, Heavy - analysis, Cadmium - analysis, Copper...