Immune system is the adaptive defense mechanism which is evolved in vertebrates to keep them from invading pathogenic microorganisms and cancer. In immune system consists of some specialized cells like: lymphocytes, neutrophils, NK cells, basophils, macrophages, eiosinophils, mast cells,
etc.Ecotoxicology is a subdisicipline of environmental toxicology concerd with studing the damaging effects of toxicants at the population and nature. Environmental toxicants are simply toxic substances in the nature. Environmental toxicant which is effect on ecosystem very badly.In
this paper we discuss that how environmental toxicant effect on immune system or immune cells.