The Hourglass: A Conceptual Framework for the Transport of Biologically Active Compounds from Agricultural Landscapes

Authors

  • Alan S. Kolok,

    Director, Interim Director
    1. Nebraska Watershed Network, Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska
    2. Department of Environmental, Agricultural and Occupational Health, Center for Environmental Health and Toxicology, University of Nebraska-Medical Center, Omaha, Nebraska
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  • Marlo K. Sellin Jeffries,

    Assistant Professor
    1. Department of Biology, Texas Christian University, Fort Worth, Texas
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  • Lindsey Knight,

    MS Student
    1. Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska
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  • Daniel D. Snow,

    Laboratory Director & Research Associate Professor
    1. School of Natural Resources, Nebraska Water Center, a part of the Daugherty Water for Food Institute, University of Nebraska-Lincoln, Lincoln, Nebraska
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  • Shannon L. Bartelt-Hunt

    Associate Professor
    1. Department of Civil Engineering, University of Nebraska-Lincoln, Peter Kiewit Institute, Omaha, Nebraska
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  • Paper No. JAWRA-13-0060-P of the Journal of the American Water Resources Association (JAWRA).
  • Discussions are open until six months from print publication.

Abstract

Recent research has suggested that the fate of biologically active compounds (BACs) originating from point sources such as wastewater treatment plants is fundamentally different from that of similar compounds released from nonpoint sources through runoff from agricultural landscapes. Downstream from wastewater treatment plants, BACs will degrade via a variety of mechanisms; however, their concentration in the water adjacent to the point of discharge may not decrease over time, as the compounds are continually released. In contrast, in agricultural systems, BACs are episodically introduced to surface water during snowmelt and rainstorm events, and under these circumstances, may be found in water for only hours or days after a storm event. Recent research in our laboratories as well as others, has suggested that sediments play an important role in the persistence of herbicides and steroids in watersheds after nonpoint source loading events. Conceptually, the sediment serves as both a sink and a source, equilibrating with BACs during storm events then slowly releasing them back into the water over time, long after the initial pulse of chemicals has moved downstream.

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