Using Model Ecosystems to Predict the Environmental Behavior of Pesticides

Abstract

WO OF THE QUESTIONS about environmental pollution that students of biology most frequently ask are: (1) How many pounds of pesticides are being put into the environment yearly? (2) Do we know where they go and what harm they do once they are applied? The first question on the use of pesticides is complicated because a number of variables affect our understanding and evaluation of use. Which chemical? Which pest? Who applies? For what purpose? Where, when, how often? Despite these uncertainties, the most recent data shows that the annual domestic use of pesticides in the United States lies between 800 million and 1 billion pounds (National Academy of Sciences 1975). Agricultural use accounts for about 60% of all applications. Table 1 shows the quantities of pesticides used by farmers in 1966 and 1971. The increases are staggering. Particularly noteworthy is the apparent increase in the relative importance of herbicides, from 33% of the total poundage in 1966 to 46% in 1971. This drastic increase reflects the need for herbicides to replace hand labor and machine cultivation. This trend is expected to continue. The second question is the more difficult. A monitoring program in the field would be one way to determine the fate and effect of these ubiquitous chemicals. However, the National Academy of Sciences (1975) has expressed concern about monitoring procedures.