The problem of pesticide contamination of running waters is one of concern in many different fields of human activity. A critical experimental approach is essential in trying to understand how individual stream fauna react and how integrated aquatic communities respond to these toxic chemicals, both over short periods and in the long term. This book, first published in 1987, deals with three aspects of pesticide contamination. First the origins of the pollutants are considered. Secondly, there follows a consideration of laboratory evaluation techniques, and thirdly, the final section of the book looks in detail at a selection of case studies in which the effects on streams of widely used pesticides are analysed. The account will be of value to freshwater biologists generally but especially to those directly involved in work with pesticides, freshwater fisheries and public health.