The problems of environmental hazardous substances: an overview

It was decided to present an overview of problems of environmental hazardous substances by selecting three areas of concern which represent different aspects of the overall subject. All three are topics of great interest at the present time. They provide examples of different causes of the hazards and different approaches to their resolution or containment. Aerial and water contamination by radon gas are a natural hazard only recently recognized. Radon can be contained, but it will require cooperative action and expenditure. Herbicides are a continuing problem demanding increased research activity to establish risk-benefit decisions. Pollution of estuaries and oceans require new development of models for establishing safe levels of some pollutants and prohibition of others.