The contextual components of ecotoxicology

Abstract

* Thought processes are contextual, so humans assimilate new information and ideas best when they can be associated with familiar contexts. In graduate school I studied freshwater protozoans, and my first professional position (summer 1948) in the Department of Limnology at the Academy of Natural Sciences in Philadelphia required that I gather information on pollution effects in aquatic communities in the Conestoga River basin ecosystem. Two river survey teams studied everything from bacteria to fish, plus water chemistry. Sampling areas were both above and below point source water discharges so that effects upon aquatic life could be compared. Occasionally, both teams would sample the same area at different times during the same day so that variability (e.g., splitters vs lumpers) could be determined. In fall 1948, a single permanent river survey team was formed, and I continued studies of freshwater protozoan communities in North America and other parts of the world (e.g., headwaters of the Amazon River). Consequently, early in my career I viewed pollutional effects in a systems context. Freshwater protozoan samples are highly perishable (also bacterial and water chemistry samples), but