In this secondary school unit, students investigate the health effects and methods for controlling polychlorinated biphenyls (PCBs). The teacher's manual contains a materials list, objectives, teaching strategies, supplementary information on PCBs, and answers to questions included in the accompanying student workbook. Activities presented include a teacher demonstration of dilution, a study of PCBs in Lake Erie white bass, and a simulation centered around policies for regulating the use of contaminated fish. (Author/WB)