2010 Annual Report
1a.Objectives (from AD-416)
The overall goal of this bridging project is to investigate the potential pollutants and agricultural management practices that affect air quality within the Chesapeake Bay region. Agricultural activities in this region have traditionally been production of corn, soybeans, and specialty crops and some confined animal operations; however, production of bioenergy crops including corn, hulless barley, and switch grass are expected to increase as energy costs rise. Urban encroachment has also become a major concern in this region resulting in increased NOx production which can lead to ozone formation in the presence of VOCs. Objective 1: Identify the major emission sources of agricultural pollutants, such as particulate, pesticide active and inert ingredients and other VOCs, and greenhouse gases within the Chesapeake Bay airshed. Objective 2: Determine the predominant fate processes and atmospheric components that influence the fate of agricultural air-borne pollutants. Objective 3: Estimate the spatial and temporal variability of emissions using a combination of field measurements, remotely-sensed, and land use data. Objective 4: Develop a framework to predict the influence of land use changes and agricultural production practices on air quality for use by policy makers, regulators, and natural resource managers.
1b.Approach (from AD-416)
Rapid detection technologies, such as nano and molecular imprinting technologies, will be developed for measuring agricultural pollutants in air. Using newly-developed and traditional techniques, the emission of air-borne pollutants will be measured in selected subwatersheds. Measurements will be taken over several growing seasons in different land use areas and compared to a previously-identified non-urban area where no agricultural activities have occurred for over thirty years. The fate of identified air borne pollutants will be examined in newly-developed chemical fate models. In areas where urban land use is adjacent to agricultural lands, available NOx and meteorological data will be utilized to predict the potential of agricultural pollutants to form ozone. Predictions will be compared to available ozone concentrations. Measured pollutant concentration data will be combined with land use, physical chemical constants, and meteorological data to produce an estimate of total emissions and potential ozone emission as a function of land use. These data will then be extrapolated to consider the effects of land-use changes and agricultural activity on air quality in the Chesapeake Bay region.
This is the final report for this project. In March 2010, this project was combined with 1265-12630-001-00D into a new project 1265-12610-001-00D. This project was a bridging project that utilized the Choptank River Watershed Conservation Effectiveness Assessment Project (CEAP) located on the Delmarva Peninsula as a platform to investigate the potential pollutants and agricultural management practices that affect air and water quality within the Chesapeake Bay region. This region can be viewed as a microcosm of environmental pressures emerging in agricultural regions across the U.S., i.e., bioenergy demand, urban encroachment, natural resource preservation, and increasing regulatory restrictions.
Results provided needed information concerning the influence of landuse, pollutant transport processes, chemistry, and seasonality on the type and extent of pollutants in the Choptank River estuary. Riparian buffers are known to mitigate overland flow and groundwater infiltration from agricultural fields, but these same tree buffers as research has shown can trap pesticide residues which can be washed off during precipitation events and enter streams and water ways. As landuse changes and as fields are brought back into production, emission of banned pesticides becomes an important pollutant source to the Chesapeake Bay and Delaware Bay watersheds. Application of biosolids from municipal waste treatment plants to agricultural lands is a useful disposal method and can condition the soil. However, some chemicals are not removed in the waste treatment process and pose a risk to the agricultural lands. Studies have shown that the flame retardants, polybrominated diphenyl ethers (PBDEs), can persist and may volatilize when the soil is cultivated.
Conclusions from this project also considered results from studies in other areas of the U.S. For example, In the Sierra Nevada Mountains, pesticide residues have been observed in air, water, and biota which have been transported via the air from the adjacent agricultural areas in the San Joaquin Valley. The obvious relationship of concentration to distance from the source, however, does not apply to all pesticides indicating that other processes are involved.
SOIL EMISSIONS ARE A POTENTIAL SOURCE OF ORGANOCHLORINE PESTICIDES TO THE CHESAPEAKE BAY. Restoration of the Chesapeake Bay, a national treasure and the largest estuary in the United States, is a national priority and federal agencies have been tasked to “use their expertise and resources to contribute significantly to improving the health of the Chesapeake Bay” (Executive Order 13508 May 12, 2009). Chlorinated insecticides were used in the Chesapeake Bay region to control termites, mosquitoes, and other insects and were banned in the 1960’s through 1980’s due to their significant toxicity to aquatic organisms, birds, and humans. ARS scientists in Beltsville, Maryland, collected air and rain samples over a four year period from three locations on the Upper Delmarva Peninsula, and overall, the levels were found to be relatively low and slowly declining. However, results also indicated that agricultural soils on the Delmarva may still contain residues of dieldrin, heptachlor, and DDE, the degradation product of DDT that can be emitted to the atmosphere from the soil and be transported. This work suggests that these chemicals in soils are a potential source to aquatic and terrestrial organisms in the Chesapeake Bay and that management strategies are needed to minimize these emissions.
MULTIPLE POLLUTANT SOURCES IDENTIFIED IN CHESAPEAKE BAY TRIBUTARY. The Chesapeake Bay is a dynamic system with pollution entering its waterways from agricultural, urban, and industrial pollution sources. A new national effort is underway to achieve meaningful reductions in the load of pollutants, especially nitrogen, phosphorus, and sediment, entering the Chesapeake Bay. ARS scientists in Beltsville, Maryland, together with state and federal partners, initiated a large detailed study of the Choptank River, tributary of the Chesapeake with heavy agricultural activity. Pollutant sources and some major factors influencing the concentrations of nutrients and other pollutants in this river were examined. Results indicated that agriculture is a primary source of nitrate (a form of nitrogen) in the river and that both agriculture and wastewater treatment plants are important sources of phosphorus. Herbicides used for weed control on crops were found in highest concentrations in the upper river near agricultural areas during the spring after planting. Copper, a metal that is very toxic to some aquatic organisms, was highest in the lower reaches of the river during the winter, possibly due to use of copper in antifouling boat paint. In addition, different types of pollutants were delivered to the river by different processes: groundwater, small streams, and atmospheric deposition. This work provides the needed data to determine the type, location, and timing of management practices that will result in most effective mitigation and improved water quality in the coastal plain areas of the Chesapeake Bay. It also serves a baseline against which to compare future changes in water quality and for the design of future monitoring programs needed to assess restoration strategy efficacy.
Andrade, N.A., Mcconnell, L.L., Torrents, A., Ramirez, M. 2009. Persistence of polybrominated diphenyl ethers in agicultural soils after biosolids applications. Journal of Agriculture and Food Chemistry. 58:3077-3084.
Bradford, D.F., Stanley, K., Mcconnell, L.L., Tallent-Halsell, N.G., Nash, M.S., Simonich, S.M., Sparling, D.W. 2010. Spatial patterns of atmospherically deposited organic contaminants at high elevation in the southern Sierra Nevada mountains, California, USA. Environmental Toxicology and Chemistry. 29:1056-1066.
Hively, W.D., Lang, M.W., McCarty, G.W., Keppler, J., Sadeghi, A.M., McConnell, L.L. 2009. Using satellite remote sensing to estimate winter cover crop nutrient uptake efficiency. Journal of Soil and Water Conservation. 64:303-313.