STP 1007 marks the beginning of the second decade of aquatictoxicology as a mature science. Papers address: Large scalecumulative effects of multiple pollution sources on regionalcommunities and populations; effects of spills, storm runoff, andother non routine exposures with complex temporal dynamics; effectsof variation in organism condition on susceptibility; predictingeffects of new chemicals whose mode of action is unknown;cumulative effects of pollution, harvesting, modifications of thephysical environment, and natural stochastic processes; andbalancing risks and benefits of different levels of testing,monitoring, and waste treatment.