The U.S. EPA has estimated that almost 1.0 billion pounds of conventional agrochemicals (active ingredient) were used annually in the US in 1995. Use on agricultural cropland accounts for over three-quarters of the agrochemicals used annually in this country, with herbicides representing the largest (83%) percentage used in crop production. Use in the home and garden is ca. 9% of all agrochemicals used (Aspelin, 1997). Agrochemicals are initially distributed in the environment at application, with the intent of maximizing efficacy while minimizing off-site movement. The Food Quality Protection Act (FQPA) has de-emphasized efficacy and set stricter standards for acceptable risks to human and environmental health. Consequently, a better understanding of initial distribution and redistribution via airborne loss, run-off and leaching is necessary to adequately characterize both human occupational and non-occupational exposure, and assess risks to biota in surrounding ecosystems.

     Responsible use of soil, air and water resources for the production of food, feed and fiber must be balanced with the need to minimize impacts on human health, and preserve natural ecosystems and the biodiversity they support. As agrochemicals remain a cornerstone of pest management in U.S. agriculture, there is a continuing need to critically evaluate environmental transport processes and factors influencing fate in assessing risk and in the development of mitigation strategies. Research is needed which provides a mechanistic understanding of fate and effects, beginning at the molecular level, and including systems analysis of agroecosystems. Such efforts will allow to a greater degree science-based decision making as a basis for policy regarding the use of agrochemicals in U. S. agriculture.

     As no production system will be appropriate for every situation, farmers need a variety of sustainable production options. The ecological risks associated with the use of agrochemicals must be evaluated. The adoption of risk assessment and risk management strategies by state and federal regulatory agencies has resulted in more general recognition of the reality of unintentional and unavoidable agrochemical exposures by handlers, harvesters, and bystanders. Measurement of the extent of human agrochemical exposure is critical to evaluation of work practices, handling and application technologies, personal protective equipment, clothing, and strategies to reduce or minimize human exposure.

     Available models for the estimation of human exposure rely almost exclusively upon environmental monitoring data and human passive dosimetry. Those data are woefully inadequate due to the number of default assumptions which must be invoked to estimate or index absorbed dosage for improved risk management and risk communication.