W2045: AGROCHEMICAL IMPACTS ON HUMAN AND ENVIRONMENTAL HEALTH: MECHANISMS AND MITIGATION
Statement of Issues and Justification
Statement of the Problem. The growing demand for food and fiber places greater strain on agricultural production and environmental stewardship. Agrochemicals will remain fundamental as integrated pest management tools to assure an abundant food supply. Inevitably, a significant portion of the applied agrochemicals will be lost to the surrounding environment, where they can adversely affect human and environmental health. The use of conventional and emerging crop protection chemistries in agricultural and urban pest management will require understanding of the fate and effects of agrochemicals, along with mitigation strategies, to minimize their risks to humans and the environment. Renewal of the W-1045 multistate research project will enable multistate collaborations to more effectively advance and transfer science to agricultural and regulatory stakeholders, who require solutions to complex human and environmental health concerns that are beyond the scope for any individual state AES or USDA-ARS unit.Justification. Over the next quarter century, the world's population is expected to increase by an unprecedented 90 million people per year. The growing demand for food and fiber will place a great pressure on agricultural production and thus growers needs for affordable and efficacious pest management. The need to increase production while reducing associated pressures of agrochemical use on natural ecosystems and human health will pose a difficult challenge for scientists in all areas of basic and applied agricultural research. Although it will be important to provide growers with a variety of biologically based, sustainable production alternatives, the use of agrochemicals will remain essential in pest management. Understanding the effects of agrochemicals on target and non-target species will improve our ability to predict and integrate current and potential pest management strategies, providing environmentally sound and cost effective approaches to pest management. These approaches will also lead to reduced application of pesticides.
Agrochemical use currently exceeds 2 billion kg each year in the United States alone (Aspelin and Grube, 1999). An unquantifiable but considerable portion of this total does not reach or leaves its target; this portion may contaminate air or water, may be transformed in the soil/air/water system, and may come into contact with non-target organisms. The continued responsible use of conventional and emerging crop protection chemistries will require a mechanistic understanding of their fate and effects and integration of this basic knowledge to develop measures to mitigate their adverse effects.
The W-1045 project focuses on building collaborations between land-grant extension specialists, researchers, USDA-ARS scientists, and institution representatives from basic and applied research disciplines to identify and develop research and strategies for understanding and minimizing adverse impacts to humans and the environment resulting from agrochemical use. This multidisciplinary effort enables technology transfer and opportunities for region-wide collaboration on complex environmental fate and effect issues that are beyond the scope of a single state AES or USDA-ARS unit. The outcomes of the W-1045 project are deliverables that can be used by regulatory agencies, growers, agrochemical manufacturers and applicators, and regional agricultural commodity groups for making scientifically sound pesticide management decisions. In partnership with NIFA, other research institutions and agencies, and the Cooperative Extension Service, renewal of the W-1045 multistate research project will further enable meaningful multistate collaborations for problem-solving on high-priority research topics while enhancing environmental stewardship.
A better understanding of off-target movement via volatilization, runoff, and leaching, and the acute and sublethal effects at the ecosystem level is essential for determining risks to biota in the surrounding environment and for characterizing human occupational and non-occupational exposures. Currently, quantifying exposure remains the weak link for evaluating risks associated with human and environmental health. Collaborations between W-1045 scientists at the University of California (Davis and Riverside), Oregon State University, and various state health regulators will have enormous implications in addressing occupational exposures. This work will include environmental and biological monitoring of a variety of work tasks of pesticide handlers and harvesters of treated crops, and residents exposed to pesticides due to indoor exposure. These data will serve to clarify the extent of risk resulting from exposure and provide exposure data for more objective establishment of field entry intervals and the effectiveness of personal protective equipment. Off-target fumigant emissions remain a primary source of non-occupational exposure at the individual and community health level. To reduce non-occupational inhalation exposures, W-1045 members at Washington State University and University of Florida are taking leading roles in developing novel technologies to reduce atmospheric emissions of fumigants while providing adequate dispersion in the root zone to achieve adequate efficacy.
Surface runoff due to irrigation and rain events carries residues of pesticides and other agrochemicals (e. g. , pharmaceuticals used in animal production) into surface aquatic ecosystems, where these compounds may exert acute and sublethal (e. g., endocrine disruption) effects on non-target aquatic organisms, including aquatic species listed as threatened under the Endangered Species Act. Similarly, pesticide residues in soil may induce endocrine disruption effects to soil-dwelling organisms due to the endocrine disruption activity of certain pesticides. Knowledge of the pathways of such exposure is also essential for the development of mitigation strategies to mitigate such nonpoint source contamination. Over the last few years, W-1045 members from University of California Riverside, Kansas State University, Purdue University, Cornell University, University of Hawaii, Oregon State University, and USDA-ARS have greatly expanded their research to address pesticide exposure and effects through non-point source pollution at various levels. The collaboration includes development of sensitive sampling and analytical methods, application of these methods for field monitoring of occurrence of pesticides, pharmaceuticals, and their metabollites, investigation of the ecotoxicological effects using various molecular biology methods, and evaluation of a range of management options to reduce the nonpoint source pollution. The outcomes of this collective effort will provide regulators with information basis for sound regulatory actions, and stakeholders such as growers with options for meeting regulatory requirements and sustaining agricultural practices in environmentally compatible manners.
Turf management (including golf courses, parks and recreation facilities, sports fields, and home residential lawns) typically involves very intensive agrochemical use patterns. Researchers at Mississippi State University will collaborate with USDA-ARS scientists in St. Paul, MN to identify environmental factors and management practices influencing agrochemical losses from turf by runoff and to develop deterministic models to estimate the impact of new and existing chemistries on aquatic systems under suburban management practices. The data gained from this research can be used to identify which compounds exceed the environments natural attenuative capacity and to develop best management practices to reduce pesticide movement to aquatic systems.
There is growing evidence that historical and current use pesticides may undergo atmospheric long-range transport (including trans-Pacific atmospheric transport) and deposition to remote high latitude and high elevation ecosystems in the U. S. These pesticides may originate in North America or may be present in Eurasian air masses. Atmospheric transport may also serve as an important pathway for pesticide distribution in the increasingly intertwined urban and agricultural communities, contributing to pesticide contamination at the watershed or airshed scale. W-1045 members from Oregon State University and USDA-ARS in Beltsville, MD, will measure historical and current use pesticides to study the fate of these compounds in sensitive, high elevation ecosystems as well as in the agricultural-urban ecosystems. The collaborative expertise, together with novel atmospheric reaction vessels and key instrument resources, will strengthen atmospheric research in evaluating and modeling distributional phenomena and gas-phase chemical reactivity, which is required for assessments of human and environmental exposure. The research results will influence regulatory strategies on the use and effects of pesticides and will aid government agencies in managing exposure to pesticides due to atmospheric transport.
Environmental exposures from the improper disposal of unwanted pesticides and rinse water from pesticide containers and application equipment can trigger regulatory actions that have immediate and irreversible consequences for agriculture. In addition, pesticides such as DDT, although banned several decades ago, are still widespread in the environment owing to their extraordinary persistence. W-1045 members at Cornell University and University of Florida are developing chemically and biologically-based remediation technology that can be utilized to remove highly concentrated pesticide wastewater or to restore environmental compartments contaminated with legacy pesticides.
Since its early beginnings, W-1045 has effectively responded to western region grower and stakeholder concerns for understanding the effects of post-application pesticide transport and fate, and the toxicological implications of agrochemical uses. Today, the work of W-1045 scientists extends well beyond the western region boundary. This growing collaboration among chemists, biologists, toxicologists, and ecologists - with expertise in the basic and applied sciences - remains essential for responding to emerging chemical fate and effect issues in accordance with the need for realistic human and environmental exposure information under the provisions of the Endangered Species Act and the Food Quality Protection Act. The strong collaborations among land-grant university scientists and extension specialists together with USDA-ARS scientists provide a unique amalgamation of research and extension capabilities. This project will continue in its goal to advance science-based strategies to prevent or mitigate adverse impacts on humans and the environment while affording joint research, extension, and training opportunities through multistate collaboration and shared use of key research and educational resources.
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