Global pesticide use is currently estimated at approximately 2. 5 billion kg per year (Pimentel eta/. , 1998). To be effective, pesticides need to persist for a certain period of time. However, the longer their persistence, the greater the potential for transport of a fraction of the amount applied away from the target area. Pesticides are dispersed in the environment by water currents, wind, or biota. Pesticides can directly contaminate ground and...