Pesticide residues in freshwater and marine zooplankton: a review.
A review of the scientific literature on pesticide residues in freshwater and marine zooplankton indicates that despite the great number of pesticides in current use, only residues of the persistent organochlorine insecticides, many of which have been restricted or removed from general use in North America, have been determined. Much of this information is outdated. In addition, with the exception of the Great Lakes on which limited information is available, reports on residues in freshwater zooplankton are rare. Information on residues of the newer, less persistent but heavily used pesticides is lacking. As an alternative to field sampling and chemical analysis of endemic populations of zooplankton, scientists have modeled the bioaccumulation of pesticides in zooplankton using either laboratory microcosms or mathematical equations. However, the extent and importance of trophic transfer to higher food levels through this intermediary group of organisms is still controversial. In addition, the relationship between accumulation of pesticides and toxicity to zooplankton remains unresolved.