continuous-instream-monitoring-nutrients-sediment-agricultural

Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in ...

Oak Ridge Institute of Science and Education (ORISE)

United States Department of Agriculture, Agriculture Research Unit USDA-ARS

Triclocarban and triclosan, two antimicrobials widely used in consumer products, can adversely affect ecosystems and potentially impact human health. The application of biosolids to agricultural fields introduces triclocarban and triclosan to soil and water resources. This research examined the phytoaccumulation of antimicrobials, effects of plant growth on migration of antimicrobials to water resources, and relevance of phytoaccumulation in human exposure to antimicrobials. Pumpkin, zucchini, and switch grass were grown in soil columns to which biosolids were applied. Leachate from soil columns was assessed every other week for triclocarban and triclosan. At the end of the trial, concentrations of triclocarban and triclosan were determined for soil, roots, stems, and leaves. Results indicated that plants can reduce leaching of antimicrobials to water resources. Pumpkin and zucchini growth significantly reduced soil concentrations of triclosan to less than 0.001 mg/kg, while zucchini significantly reduced soil concentrations of triclocarban to 0.04 mg/kg. Pumpkin, zucchini, and switch grass accumulated triclocarban and triclosan in mg per kg (dry) concentrations. Potential human exposure to triclocarban from consumption of pumpkin or zucchini was substantially less than exposure from product use, but was greater than exposure from drinking water consumption. Consequently, research indicated that pumpkin and zucchini may beneficially impact the fate of antimicrobials in agricultural fields, while presenting minimal acute risk to human health.

Phytoaccumulation of antimicrobials from biosolids: impacts on environmental fate and relevance to human exposure.

Consumer use of antimicrobial-containing products continuously introduces triclocarban and triclosan into the environment. Triclocarban and triclosan adversely affect plants and animals and have the potential to affect human health. Research examined the phytoaccumulation of triclocarban and triclosan by pumpkin (Cucurbita pepo cultivar Howden) and zucchini (Cucurbita pepo cultivar Gold Rush) grown hydroponically. Pumpkin and zucchini were grown in nutrient solution spiked with 0.315 microg/mL triclocarban and 0.289 microg/mL triclosan for two months. Concentrations of triclocarban and triclosan in nutrient solutions were monitored weekly. At the end of the trial, roots and shoots were analyzed for triclocarban and triclosan. Research demonstrated that pumpkin and zucchini accumulated triclocarban and triclosan. Root accumulation factors were 1.78 and 0.64 and translocation factors were 0.001 and 0.082 for triclocarban and triclosan, respectively. The results of this experiment were compared with a previous soil column study that represented environmentally relevant exposure of antimicrobials from biosolids and had similar root mass. Plants were not as efficient in removing triclocarban and triclosan in hydroponic systems as in soil systems. Shoot concentrations of antimicrobials were the same or lower in hydroponic systems than in soil columns, indicating that hydroponic system does not overpredict the concentrations of antimicrobials.

Niroj Aryal

Oak Ridge Institute of Science and Education (ORISE)

Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds