Evaluating the Physical and Biological Availability of Pesticides and Contaminants in Agricultural Ecosystems

Non-Technical Summary:<br/>
Land application of biosolids and reclaimed water irrigation are quite popular practices worldwide, the former in both humid/dry regions and the latter in semi-arid/arid areas. Both practices offer numerous benefits (reliable water supply from reclaimed water; nutrients + organic matter inputs) that could enable agricultural production to be more sustainable, an important consideration given increasing global food demand and erratic rainfall patterns. However, the presence of certain constituents could impose restrictions and create serious environmental risks. Specifically, pharmaceuticals and personal care products (PPCPs), a subset of chemicals of emerging concern (CEC), deserve serious attention as wastewater treatment processes are not effective in their removal and they have been detected in wastewater effluents, biosolids and biosolid-applied soils, besides surface and ground waters. These CECs can be taken up by crop plants and there is a paucity of information on polar/ionogenic CECs (characteristics of PPCPs) and underlying mechanisms for CEC translocation to different plant components are poorly understood. We will systematically evaluate the bioaccumulation of CECs with contrasting chemical characteristics by crop plants differing in their edible parts (tomato, carrot, and spinach). Specific objectives are to: a) determine the role played by soils and biosolids on the bioaccumulation potential of CECs, and b) elucidate the influence of CEC chemical characteristics on plant uptake. Project results will increase our understanding of the fate of wastewater-derived chemicals (in biosolids and treated effluents) in agricultural systems.
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Approach:<br/>
The proposed project will investigate the bioaccumulation of different (and chemically distinct) chemicals of emerging concern (CECs) by three types of agricultural crops under controlled-environmental conditions. Greenhouse hydroponic experiments will be conducted in the absence (soil-less) and presence of soils and with and without biosolids amendment. In addition, batch experiments will be performed to quantify sorption of CECs to soils and biosolids-derived dissolved organic matter. Thirteen CECs have been selected based on their occurrence in treated wastewater or biosolids. We intend to use Brassica rapa (Wisconsin fast plants) for initial screening of plant uptake of CECs (all 13 CECs will be tested) in soil-less hydroponic systems. Fast plants can be easily grown hydroponically. We will investigate uptake of all target CECs in fast plants. From the CECs that are efficiently taken up by Brassica rapa, we anticipate choosing 4-5 compounds for further investigation of uptake by spinach, carrot and tomato in hydroponic (soil-less) systems. To determine the influence of soils and organic matter (from biosolids) on CEC bioaccumulation, counterpart greenhouse studies will be conducted. These experiments represent flow-through irrigation systems with reclaimed wastewater in the presence and absence of biosolids. From the hydroponic studies, three CEC compounds with highest plant uptake potential with varying chemical characteristics will be chosen for subsequent pot experiments. Greenhouse pot experiments will involve three CEC compounds, two soil types (silt loam and loamy sand), three plants (+ one plant-free control). Experiments will be conducted with and without biosolids amendment. Results will be used to determine influence of CEC chemical characteristics on their accumulation in different plant components. We plan to extract CECs from water, soils, biosolids and plant tissues and analyze them by LC-MS. Targeted audiences of the proposed work include agricultural producers, environmental research community, environmental consultants, regulatory agencies, and coordinators of biosolids land application program. The project will result in accelerated solvent extraction and LC-MS/MS methods optimized to recover and measure selected CECs in plant matrices, rigorous quantification of the extent of CEC uptake by food crops (in the presence and absence of soils and biosolids), and improved understanding of the influence of physico-chemical properties on CEC uptake by plants. Project results will increase our understanding of the fate of wastewater-derived chemicals (in biosolids and treated effluents) in agricultural systems. Deliverables include annual reports and research articles. Results will be disseminated at the Tri-Societies (ASA-SSSA-CSA) meetings, ACS, SETAC, and published in peer-reviewed journals.
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Progress:<br/>
2012/01 TO 2012/12<br/>
OUTPUTS: Land application of biosolids and reclaimed water irrigation are quite popular practices worldwide, the former in both humid/dry regions and the latter in semi-arid/arid areas. Both practices offer numerous benefits (reliable water supply from reclaimed water; nutrients + organic matter inputs) that could enable agricultural production to be more sustainable, an important consideration given increasing global food demand and erratic rainfall patterns. However, the presence of certain constituents could impose restrictions and create serious environmental risks. Specifically, pharmaceuticals and personal care products (PPCPs), a subset of chemicals of emerging concern (CEC), deserve serious attention as wastewater treatment processes are not effective in their removal and they have been detected in wastewater effluents, biosolids and biosolid-applied soils, besides surface and ground waters. These CECs can be taken up by crop plants and there is a paucity of information on polar/ionogenic CECs (characteristics of PPCPs) and underlying mechanisms for CEC translocation to different plant components are poorly understood. To address these knowledge gaps, we will systematically evaluate the bioaccumulation of CECs with contrasting chemical characteristics by crop plants differing in their edible parts (tomato, carrot, and spinach).
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Specific project objectives are to: a) determine the role played by soils and biosolids on the bioaccumulation potential of CECs, and b) elucidate the influence of CEC chemical characteristics on plant uptake. Project results will increase our understanding of the fate of wastewater-derived chemicals (in biosolids and treated effluents) in agricultural systems. Targeted audiences of the proposed work include agricultural producers, environmental research community, environmental consultants, regulatory agencies, and coordinators of biosolids land application program. The project will result in accelerated solvent extraction and LC-MS/MS methods optimized to recover and measure selected CECs in plant matrices, rigorous quantification of the extent of CEC uptake by food crops (in the presence and absence of soils and biosolids), and improved understanding of the influence of physico-chemical properties on CEC uptake by plants. Deliverables include annual reports and research articles. Results will be disseminated at the Tri-Societies (ASA-SSSA-CSA) meetings, ACS, SETAC, and published in peer-reviewed journals.
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PARTICIPANTS: 1) Ms. Sara Nason - Ph.D. student (Environmental Chemistry & Technology), University of Wisconsin-Madison. 2) Ms. Elizabeth Miller - Ph.D. student (Molecular and Environmental Toxicology), University of Wisconsin-Madison. 3) K.G. Karthikeyan - project PI. 4) Joel Pedersen - project PI. 5) Curtis Hedman - Wisconsin State Laboratory of Hygiene.
<br/>TARGET AUDIENCES: Targeted audiences of the proposed work include agricultural producers, environmental research community, environmental consultants, regulatory agencies, and coordinators of biosolids land application program.
<br/>PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
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IMPACT: The proposed project will investigate the bioaccumulation of different (and chemically distinct) chemicals of emerging concern (CECs) by three types of agricultural crops under controlled-environmental conditions. Greenhouse hydroponic experiments will be conducted in the absence (soil-less) and presence of soils and with and without biosolids amendment. In addition, batch experiments will be performed to quantify sorption of CECs to soils and biosolids-derived dissolved organic matter. Thirteen CECs have been selected based on their occurrence in treated wastewater or biosolids. We will use Arabidopsis Thaliana for initial screening of plant uptake of CECs (all 13 CECs will be tested) in soil-less hydroponic systems. We will investigate uptake of all target CECs by Arabidopsis. From the CECs that are efficiently taken up by Arabidopsis, we anticipate choosing 4-5 compounds for further investigation of uptake by spinach, carrot and tomato in hydroponic (soil-less) systems. To determine the influence of soils and organic matter (from biosolids) on CEC bioaccumulation counterpart greenhouse studies will be conducted. These experiments represent flow-through irrigation systems with reclaimed wastewater in the presence and absence of biosolids. From the hydroponic studies, three CEC compounds with highest plant uptake potential with varying chemical characteristics will be chosen for subsequent pot experiments. Greenhouse pot experiments will involve three CEC compounds, two soil types (silt loam and loamy sand), three plants (+ one plant-free control). Experiments will be conducted with and without biosolids amendment. Results will be used to determine influence of CEC chemical characteristics on their accumulation in different plant components. We plan to extract CECs from water, soils, biosolids and plant tissues and analyze them by LC-MS. This project commenced only in Sep. 2012 and relevant activities conducted to date (4 months) include: (a) Recruitment of 2 Ph.D. level graduate students (Ms. Sara Nason and Ms. Elizabeth Miller) to work on this project, (b) Selection of Arabidopsis thaliana as the initial test plant including investigation of previous work and availability of mutants that can be used to isolate CEC transport pathways, (c) Final selection of test CEC compounds including compilation of essential physic-chemical properties, (d) Design of hydroponic system for growing Arabidopsis Thaliana, (e) Investigation of specialized methods to grow carrots hydroponically, (f) Optimization of LC-MS/MS methods for detection of selected CECs including initial training of graduate students to use this instrument, and (g) Initial testing of accelerated solvent extraction methods for plant samples.