Environmental pollution and toxic substances: Cellular apoptosis as a key parameter in a sensible model like fish

•High level of metals act as apoptotic process inductor on several key tissues.•HSP70 and metalloprotein are able scarcely to block the apoptosis process.•BKPME, POPs and PAH induce in fish high levels of apoptosis.•Insecticides are in grade to provoked apoptosis in liver, gonads, kidney and blood.•Biological compounds, like bacterial-lypopolysaccaride are able to induce apoptosis.