This dictionary, compiled and judiciously edited in single volume, deals with the term? related to water and marine pollution, their adverse effects on human beings and the environment, as well as various methods of their control. The dictionary includes those terms which are in most common use throughout the world. The definitions are written in clear and simple language that is understandable even to non-specialists but is consistent with the complexity of the term itself. Line dra wings have been included whenever the meaning of a term can be best understood by means of a diagram. The network of cross- references has been kept throughout the dictionary. This dictionary serves the compelling demands of the environmentalist, civil and environmental engineers, operators of water treatment plants, marine engineers, oceanologists, mariners, hydrologists environmental protection agencies, conservationists, law (11 forcement agencies public administrators and such persons who are evolved directly or indirectly with water and marine pollution.