W082: Reducing the Potential for Environmental Contamination by Pesticides and Other Organic Chemicals
Statement of Issues and Justification
STATEMENT OF PROBLEM: Agricultural activity while essential in meeting the dietary needs of the world can result in the contamination of soil, air, and water resources. Identifying and adequately quantifying the chemical and biological processes that control the behavior of organic chemicals in the environment is imperative towards improving pesticide management, minimizing contamination of our natural resources, and remediating contaminated environments.JUSTIFICATION: Use of organic chemicals by all sectors of the economy has resulted in widespread contamination of soil, air, and water. Because chemical technology is generally recognized as having great societal benefit compared to the risks, it is critical that approaches and tools for managing chemical use are developed in order to minimize future contamination and to remediate contaminated environments. Evaluating and quantifying the environmental behavior of organic chemicals is vital towards the development of sound strategies for ensuring sustainable agriculture and protecting natural resource systems. A major societal concern regarding chemical contamination is pesticide residues in our environment and food. Pesticide use will continue to decline as a result of improved integrated pest management (IPM) systems and development of sustainable, integrated farming systems. Nevertheless, use of pesticides will remain a mainstay within production systems, especially for the many crops for which IPM systems have not been developed. Research is needed on identifying efficient pesticide use practices with minimal environmental impacts. Newly developed pesticides, many of which are applied at rates one-tenth or less of conventional pesticides, are often highly toxic to nontarget crops or aquatic organisms; thus, knowledge is needed of the transport and fate of these substances. In addition to pesticides, the environmental fate of pharmaceutically active substances is a rising concern. Pharmaceutical substances, which are designed to cause a biological effect and are usually organic in nature, have a high potential for being a major player in endocrine disruption. Almost half of the fifty million pounds of antibiotics produced annually in the United States is used for agriculture, with the majority being used as feed additives for growth promotion. With increases in the intensive use of antibiotics in concentrated animal feeding operations and land application of manure, there are concerns that excreted pharmaceuticals will migrate in the environment with potential impacts on water supplies and the production of antibiotic-resistant microbial populations. Recent research has shown a high percentage of multiple-antibiotic resistant microbial populations in litter from broiler houses. In large animal feeding operations antibiotics could be highly concentrated in animal wastes and associated lagoons. Little effort to date has been put forth with regards to the potential of these organic substances impacting ground and surface waters, their impact on soil microbial communities, and their overall persistence in the environment. A better understanding of the environmental fate of antibiotics is needed to assess the environmental risk involved in exposing animal wastes to the environment. Organic chemicals not necessarily identified with the agricultural industry are also of interest. For example, petroleum products or "inert" materials (e.g. solvents, emulsifiers) are present in pesticide formulations and are commonly used on farms. Also, as areas of urban and rural land use increasingly overlap, these often conflicting communities impact one another through their chemical use patterns. The principles governing the behavior of organic chemicals in the environment are the same regardless of how these chemicals are used. Therefore, both urban and rural sectors of the economy can benefit from basic and applied studies of all organic chemicals whether they are used in agro-ecosystems or are associated with hazardous waste sites. Over the last several decades, the agricultural science community has conducted most of the research on the environmental behavior of organic chemicals regardless of their source. Much of the current research on the environmental behavior of industrial chemicals is dependent on basic principles originally derived in the study of pesticides, some of which resulted from research by W-82 members. The fate and accumulation of organic compound residues are mediated by various, often tightly coupled, processes including advection and diffusion, sorption and desorption, biodegradation, and chemical reactions. These processes occur within and between intimately associated environmental compartments (soil, water, air, and biota). For example, chemical interactions with the soil controls chemical persistence, release into water and air, and bioavailability, which impact pesticide efficacy, degradation, and off-site transport. Because of the complexity of interactions among chemical properties, environmental compartments, and spatial and temporal scales, research involving environmental pollution requires a multi-disciplinary approach. A unique strength of the W-82 committee is the close research collaboration among its members from different scientific disciplines who, outside the committee, do not have sufficient opportunity to communicate with one another. W-82 provides a forum where specialists in mechanisms of chemical behavior, microbial ecology, transport behavior, mathematical modeling, and field assessment techniques can come together, and exchange information gleaned from individual or cooperative research efforts. Such cooperative efforts between research groups representing different expertise and diverse geographical areas are imperative developing appropriate management techniques for minimizing environmental contamination and thus risk. The goal of W-82 research is to minimize environmental contamination from pesticides and other organic chemicals. W-82 proposes to carry out a cooperative and interdependent research program that elucidates fundamental mechanisms of chemical behavior and applies this knowledge to different spatial and temporal scales. In combination with mechanistic models, the principles of chemical behavior will be integrated to form management models and propose and assess best management techniques. Research carried out by W-82 will be useful in the continued development of best management practices for minimizing environmental contamination, as well as, the development of efficient and comparatively inexpensive strategies for remediating contaminated environments. Results of the research proposed by W-82 will be applicable to agro-ecosystems in addition to urban systems, and will fulfill USDA needs with regards to protection of water quality and development of integrated agricultural systems as well as the USDA mission for serving the dominant urban sector of our economy. By developing better management techniques the risks of adverse environmental and health effects of our chemical technology will be greatly minimized.
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