ABSTRACT
Brown et al. (1972) defined pollution as the ‘addition of chemical, physical or biological substances or of heat, which causes deterioration in the natural quality, generally through the action of man or animals or any other kind of activity.’ More specifically, Walker (1969) defined pollution as ‘an impairment of water quality by chemicals, heat, or bacteria to a degree that does not necessarily create an actual public health hazard, but that does adversely affect such waters for normal, domestic, farm, municipal or industrial use.’ On the other hand, Walker used the term contamination to denote ‘impairment of water quality by chemical or bacterial pollution to a degree that creates an actual hazard to public health.’
