Fate of Pesticides in Aquatic Environments

Abstract

In the short time available it is obvious justice cannot be done to the subject of this presentation and that a high degree of selectivity combined with a great deal of ability to compress and summarize data will be required. For this reason it will be assumed that the pesticide has already been transported to aquatic ecosystems from direct application, from runoff waters, or from the atmosphere. Once it is in the aquatic system, it may be rapidly degraded by a variety of mechanisms or persist for a period of time. Its persistence and, therefore, its potential for biomagnification will be determined by a variety of factors. Perhaps the most important single factor is the ability to partition into lipid-rich pools. Fat-soluble, water-insoluble materials, e.g., DDT, PCBs, accumulate into “environmental sinks” and, by virtue of their water insolubility, resist the usual transformation and detoxification mechanisms and provide a virtually constant input source of material. These are the environmental “bad guys” and one must be careful not to include all pesticides in this category.