Pesticides have played a significant role in increasing food production, and in view of growing worldwide food demand we can expect the use of these chemicals to increase. However, some of them have found their way into the biosphere and have been classi fied as persistent toxic chemicals. This has resulted in serious concern about environmental contamination. Since we are going to continue using chemicals, we should learn more about such aspects as their transport in the environment, the relationship of their physical-chemical properties to transport, their persistence in the biosphere,...