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JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH Dr. Shahamat U. Khan JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH, Part A Dr. Shahamat Khan is a world renowned authority on humic materials and bound residues. His research interest pertaining to CCWST is described as follows. Pesticides in Sediments and Water. Shahamat U. Khan About one billion pounds of pesticides are used each year in the United States to control weeds, insects, and other organisms. About 80 % of this quantity is used in agriculture. Although the use of pesticides has resulted in increased crop production and other benefits, it has raised concerns about the potential adverse effects on the environment and human health. In many respect, the greatest potential for unintended adverse effects of pesticides is through contamination of the hydrologic system. Water is one of the primary pathways by which pesticides are transported from their application areas to other parts of the environment. There is considerable information in the literature on pesticides in bed sediments and aquatic biota in rivers and estuaries. However, still there are gaps in our standing of the distribution and trend in pesticide contamination in bed sediments and aquatic biota. There is little known on the extent of contamination of currently used pesticides, including the few organochlorine insecticides still permitted for use in agriculture as well as certain pesticides that are moderately hydrophobic and moderately persistent. Although large scale monitoring of these compounds in stream sediments and aquatic biota may not be warranted, it may be reasonable to monitor such pesticides in areas of known high or repeated use, or in association with specific land use or crops. There is much to be learned about the biological significance of pesticide residues in hydrologic systems. Some research areas are particularly compelling: for example, the effects of chemical mixtures and potential adverse effects on aquatic life, wildlife, human health due to endocrine disruption. It is hoped that in the new center a multidisciplinary research efforts that combine chemistry, hydrology, and ecotoxicology will provide a more complete perspective of the occurrence, distribution and significance of pesticides in bed sediments and biota of rivers and lakes which support aquatic life and related food chains and is used for recreation, drinking water, irrigation, and many other purposes.
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