Elements of environmental science and how the science is related to the more traditionally established disciplines are explored in this supplementary text. Two aspects of environmental science are considered--subject matter and decision making. Relevant background material in the physical sciences is presented under the following topics: ecology, agricultural environments, pesticides, radioactive wastes, air pollution, water pollution, solid wastes, growth of human populations, thermal pollution, and noise. Study problems are given in each chapter with numerical answers provided for those requiring computations or mathematical reasoning. The second aspect deals with the decisions people make about environmental problems. A discussion of social problems and issues is offered to show how various scientific and economic factors must be taken into account so that final judgements do not lead to unwanted results. Bibliographic references appear at the end of each chapter with the appendix giving information on units of measurement and chemical formulas. The text would be useful for students in an introductory environmental science course as well as supplement a standard course in biology or chemistry. (BL)