Pollutants which are slowly degradable and remain in the environment in an unchanged for many decades, termed as :

Pollutants which are degraded slowly, remain in the environment in an unchanged form for many decades called as non-biodegradable pollutants. E.g., DDT (dichloro di phenyl trichloroethane) Plastic materials, heavy metals nuclear waste etc., and pollutants which are degraded by natural process rapidly called biodegradable pollutants e.g., vegetable wastes and domestic sewage etc.