Submitted to: Annual International SWAT Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/17/2010
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The impact of anthropogenic chemicals on water quality, wildlife, and human health has received increasing attention in recent years. One potential source of anthropogenic compounds is land-based recycling programs which apply municipal wastes (biosolids) to large tracts of agricultural land in lieu of chemical fertilizers. Fertilizing with biosolids may increase the risk of soil and water pollution by excess nutrients, metals, endocrine disrupting chemicals (EDCs), and other organic contaminants. It is also unclear how these compounds move through soils to enter natural waters and how different land-based recycling management strategies could be used to minimize chemical movement and transport. We used the USDA-ARS’s Soil and Water Assessment Tool (SWAT) pesticide submodel to simulate potential movement of 17ß-estradiol through soils at a municipally-operated beneficial reuse site in central Texas that surface applies biosolids to agricultural land for commercial forage production. Specifically, we were interested in the effects of cropping system affects EDC movement, as well as the effects of uncommon, large rainfall events that could potentially flush EDCs from biosolids-applied areas. Two simulations were run (1980-2006, 1980-2007) in which one simulation included a historically high 2007 rainfall year. SWAT simulations showed that the perennial biofuel crop switchgrass reduced leaching of 17ß-estradiol through surface soils (A horizon) by 21-23% compared to the current coastal Bermudagrass forage crop. No leaching of 17ß-estradiol was simulated to occur through the bottom of the soil profile (1.5 m), but leaching through surface soils (A horizon) increased by 90% with the inclusion of the 2007 rainfall year. Our results suggest that anomalous rainfall events may trigger flushes of EDCs through the soil. The results from this study will be used to aid the development of an emerging contaminants sub-model in SWAT for predicting transport and fate of EDCs and other biosolids-derived organic pollutants. Ultimately, our research findings will assist the development of more sustainable, economically and ecologically sound land-based biosolids recycling management plans.