The Aberjona watershed, north of Boston, Massachusetts, has a long industrial history and contains numerous chemical pollutants, many of known or suspected toxicity to humans. Home to over 50,000 people, the Aberjona watershed is the focus for a collaboration of toxicologists, hydrologists, and environmental chemists. Collectively, we seek to reveal the chain(s) of events by which chemical releases into the environment, environmental transport and transformation, human exposure processes, and biochemical/genetic damage, can collectively result in adverse human health effects. This proposal deals with the environmental links of these chains. The emphasis is on understanding how major classes of toxic chemicals, including heavy metals and volatile organic compounds (VOC's), are transported and transformed on the watershed, ultimately reaching human receptors. We have also documented sediment-associated mutagenicity to human cell lines on this watershed. In continued work, we will investigate the mutational spectra caused by these sediments, and will seek the identity of the mutagenically active compound(s) of these complex mixtures.