Location: Hydrology and Remote Sensing Laboratory2013 Annual Report
1a. Objectives (from AD-416):
Discern the chemical nature, fate, and transport of critical agricultural pollutants emitted to the atmosphere and consider the potential risks posed by reactivity and/or deposition of these chemicals to sensitive ecosystems. Disseminate results to customers concerning the effects of atmospheric agricultural pollutants on environmental quality.
1b. Approach (from AD-416):
Measure ambient concentrations of agricultural pollutants in soil and in air across the agriculture-urban transect of the Chesapeake Bay watershed. Compare volatile organic compound and particulate matter emissions from poultry production under different ammonia management practices. Test novel approaches to fingerprint particulate matter sources chemically and evaluate the fate and transport of critical agricultural pollutants for estimating potential risks using regional-scale atmospheric transport and deposition modeling tools.
3. Progress Report:
Progress on this project has been enhanced through collaborations established via the ARS Air Quality Workgroup and competitive grants. Under Sub-objective 1, three air quality stations spanning the agriculture-urban interface have been established at the Beltsville Agricultural Research Center (BARC) (urban); the Smithsonian Environmental Research Center (SERC) (Chesapeake Bay/forested); and at a poultry farm in the Choptank River watershed (agricultural). Samplers for the BARC site were installed at the Natural Resources Conservation Service Plant Materials Center (1265-12610-001-10N). Under Sub-objective 2, a USDA-NRCS Conservation Innovation Grant (University of Delaware, PI) was written and funded entitled, “Innovative Approaches to Capture Nitrogen and Air Pollutant Emissions from Poultry Operations: Demonstrating and Quantifying the Effectiveness of Vegetative Environmental Buffers (VEBs) Combined with Acid Scrubbers”. This project is being carried out in collaboration with the University of Delaware, University of Maryland, Penn State University, Oklahoma State University (1245-12610-001-03S), ARS-Fayetteville (6226-63000-003-00D), and ARS-Lubbock (6208-66000-003-00D). Other ARS Air Quality Workgroup members from ARS-Ames (3625-11610-001-00D) and from University of Iowa participated using advanced LiDAR and meteorological equipment. In separate experiments to examine gas-phase pollutant mitigation, a combination of NH3 and CH4 were released and monitored downwind of the buffer. Scientists from ARS-Florence (6657-13630-005-00D) participated by providing expertise and tunable diode laser equipment. Also, under Sub-objective 2, development and refinement of an atmospheric particulate fingerprinting methodology using Raman microscopy was completed. Originally, this work was to be conducted using particles captured at poultry facilities, but particles from a large cattle feedlot were utilized instead. Samples were collected in a collaborative study with Kansas State University, ARS-Ames, IA, and ARS-Florence, SC, which was partially funded by an Agriculture and Food Research Initiative grant (1245-12610-001-01R). A key personnel change resulted in loss of expertise in Raman spectroscopy needed to continue along this line of research. Since a critical vacancy has also removed the atmospheric modeling expertise from this project, the focus of Sub-objective 3 has changed from the development soil emission potential to the bioavailability of pollutants to soil-borne organisms. A novel and inexpensive method has been successfully tested and shown to simulate the bioavailability of hydrophobic organic pollutants in soil to earthworms. This effort has been bolstered by collaboration with the University of Maryland (1245-12000-040-20S) and where a former orchard contaminated with the pesticides DDT and dieldrin has been utilized. This approach is being further tested through collaboration with the District of Columbia Water and Sewer authority and University of Maryland (1245-12610-001-02S) to examine the bioavailability of brominated flame retardants associated with biosolids that has been applied to agricultural soils.
1. Innovative method developed to determine the bioavailability of legacy pesticides in soil. DDT and dieldrin are pesticides that were banned in the 1970s due to toxic effects on wildlife like eagles, yet some agricultural soils like orchards still contain high levels of these compounds. To protect ecosystem and human health, improved approaches are needed to assess the bioavailability of these compounds rapidly, accurately, and inexpensively. ARS researchers at Beltsville, Maryland in collaboration with University of Maryland have developed a new approach to determine the bioavailability of these highly toxic compounds in soils without using earthworm testing. The thin-film-solid phase extraction method (TF-SPE) was shown to be highly correlated with the much more laborious and expensive earthworm bioassay. This new procedure will greatly enhance the ability of land managers and regulatory agencies to manage soils that are highly contaminated with legacy pesticides such as former orchards.
2. Insecticide concentrations in rain exceed toxicity thresholds in South Florida. The environmental health of the fragile ecosystems in South Florida is declining, much of it due to increased nutrient inputs from agricultural activities and urban encroachment. Recent work has indicated that the frequent use of pesticides, high humidity and temperatures, frequent rainfall and irrigation, soil type and structure enhance the release of applied pesticides to the atmosphere. ARS researchers from Beltsville, Maryland and Tifton, Georgia in collaboration with University of Florida examined the fate of the insecticide endosulfan, a major hazard potential to aquatic organisms in this region, in the air and the extent of its deposition via rainfall to the Homestead agricultural area and Everglades and Biscayne National Parks. During the growing season, endosulfan concentrations frequently exceed the concentrations for aquatic life toxicity thresholds at all sites, indicating that endosulfan volatilization and subsequent wet deposition are of ecotoxicological concern to the region. These data will be useful for regulators, extension specialists, and decision-makers in modifying agricultural management practices to protect sensitive ecosystems.
Bradford, D.F., Stanley, K.A., Tallent-Halsell, N.G., Sparling, D.W., Nash, M.S., Knapp, R.A., Simonich, S.M., Mcconnell, L.L. 2013. Temporal and spatial variation of atmospherically deposited organic contaminants at high elevation in Yosemite National Park, California, USA. Environmental Toxicology and Chemistry. 32:517-525.