Gas Chromatography-Mass Spectrometry, Metals - analysis, Hydrocarbons - toxicity, Metals - toxicity, Brachyura - metabolism, Brachyura - drug effects, Geologic Sediments - chemistry, Water Pollution, Chemical - adverse effects, Seasons, Spectrum Analysis, Tunisia, Quality Control, Biomarkers - metabolism, Oceans and Seas, Ecotoxicology - methods, Digestive S...