Monday, November 5, 2007
93-5

The Fate and Environmental Impact of Antibacterial Agents Triclosan and Triclocarban in Soil Receiving Long Term Biosolids Application.

Kang Xia1, Lakhwinder Hundal2, Mark A. Williams3, Kusum Verma1, Albert Cox2, Kuldip Kumar2, Thomas Granato2, Richard Lanyon2, and Kevin Armbrust1. (1) PO Box Cr, Mississippi State University, Mississippi State University, 3316 Hand Lab, Morrill Rd., Mississippi State, MS 39759, (2) Illinois, State of, 6001 W Pershing Road, Lue-Hing R&D Complex Section 123, Cicero, IL 60804-4112, (3) Plant and Soil Sciences, Mississippi State University, Rm 117 Dorman Hall, Stone Bldvd, MSU, MS State, MS 39762

Farmland application of biosolids is the most sensible and cost-effective option for many municipalities and it provides tremendous savings in fertilizer costs to the farmers. However, environmentalists continue to raise concerns about the safety of this practice because biosolids may contain traces of organic compounds, such as pharmaceuticals and personal care products (PPCPs).  Triclosan and triclocarban, both are widely used antibacterial agents in a variety of personal care products, are of particular interest because of concerns about their accumulation in soil receiving biosolids application may result in increased antibiotic resistance population of microorganisms in the environment. We investigated concentrations of triclosan and triclocarban in biosolids collected from 16 wastewater treatment plants in five U.S. states. We also evaluated their levels and populations of antibiotic resistance microorganisms in soil samples from our long-term plots that have been receiving annual applications of biosolids since 1973. The transformation mechanisms of the two compounds in soils were studied. At the end of 2002, the cumulative biosolids loadings were 0 (control), 504, 1008, and 2016 Mg dry biosolids per hectare in the plots. The average levels of triclosan and triclocarban were 52 ppb and 1035 ppb, respectively, in the topsoil samples (0 – 6 in) from plots receiving the highest biosolids application. The levels of triclocarban and triclosan increased with increasing biosolids application rate. Their levels decreased significantly with soil depth. For plots receiving the highest biosolids application, concentrations of triclocarban and triclosan decreased to 23 ppb and 19 ppb, respectively, at a depth of 24 - 48 in. Our results indicated that the levels of triclocarban detected in the soils receiving long-term biosolids application did not increase the population of microorganisms that are resistance to antibiotics.

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