Brief Summary of Minutes of Annual Meeting

Objective 1: Identify, develop, and/or validate trace residue analytical methods, immunological procedures, and biomarkers. Cyromazine is used as an additive in poultry feed to inhibit the development of fly larvae in chicken manure. U.S. Environmental Protection Agency (EPA) method AG-555, modified from method AG-376, has been the standard method for cyromazine analysis in poultry feed. However, these methods are time-consuming (3 h) and require large volumes (200 mL) of solvent. Scientists at Mississippi State University developed an extraction procedure using the QuEChERS method that is faster (30 min) and uses 20 times less solvent than the AG-555 method. After extraction using the QuEChERS method, the extractant was subjected to cleanup using a C-18 solid phase extraction (SPE) followed by filtering through a 0.45 ¼m syringe Teflon filter before liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Recovery of 75.0 ± 6.2% was achieved. The method detection limit (MDL) and the limit of quantitation (LOQ) were 0.028 and 0.094 ppm, respectively. Analyses of commercial poultry feed samples using the QuEChERS method yielded results similar to those obtained via EPA method AG-555. Organochlorine pesticides (OCPs) are of concern due to their contamination in foods. Scientists from the University of Hawaii (Honolulu) measured quantities of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), chlordane and hexachlorobenzene (HCB) in 38 honeys labeled from different geographic regions using gas chromatography/ion trap mass spectrometry after accelerated solvent extraction. Mean concentrations (ranges) of HCHs, DDTs, chlordane, and HCB in tested honeys were 2.23 (0.21-8.70), 1.14 (0.10-4.35), 0.45 (0.02-3.75), and 0.17 (nd-1.16) ng g-1, respectively. Concentration ranges of total HCHs (SHCHs), SDDTs, and Schlordane and HCB were 0.21-8.70, 0.10-4.35, 0.02-3.75, and nd-1.16 ng g-1, respectively, in the 38 honeys. Honey samples from developing countries generally contained higher concentrations of SHCHs, SDDTs, Schlordane, and HCB than those from developed countries. Comparison of the ratios of highest and lowest concentrations of SHCHs, SDDTs, Schlordane, and HCB in honeys from developing and developed countries showed relatively similar concentrations of the OCPs in honeys from developing countries and large variation in honeys from developed countries. Scientists from Kansas State University evaluated the expression of two chitin synthase genes, AgCHS1 and AgCHS2, to determine if they would be repressed by the chitosan/AgCHS double-stranded RNA (dsRNA)-based nanoparticles through larval feeding in Anopheles gambiae. The AgCHS1 mRNA level and chitin content were reduced by 62.8 and 33.8%, respectively, in the larvae fed on the chitosan/AgCHS1 dsRNA nanoparticles compared with those of the control larvae fed on the chitosan/green fluorescent protein (GFP) dsRNA nanoparticles. The study demonstrated the larvae that fed on the nanoparticles had increased susceptibility to diflubenzuron, and calcofluor white or dithiothreitol, respectively. These results suggest a great potential of using such a nanoparticle-based RNAi technology for developing novel strategies for insect pest management. Objective 2: Characterize abiotic and biotic reaction mechanisms, transformation rates, and fate in agricultural and natural ecosystems. Minimizing atmospheric emissions of soil fumigants is critical for protecting human and environmental health. Covering the soil surface with a plastic tarp is a common approach to restrict fumigant emissions. The mass transfer of the fumigant vapors through the tarp is often the rate-limiting factor in fumigant emissions. Scientists from Morris, MN, developed an approach for standardizing measurements of film permeability based upon determining the resistance (R) of films to diffusion of fumigants. Using this approach, R values were determined for more than 200 film-chemical combinations under a range of temperature, relative humidity, and film handling conditions. Resistance to diffusion was specific for each fumigant/film combination with the largest range of values observed for the fumigant chloropicrin. For each fumigant, R decreased with increasing temperature. Changes in film permeability due to increases in temperature or field installation were generally less than a factor of five. For one film, R values determined under conditions of very high relative humidity (~100%) were at least 100 times lower than when humidity was very low (~2%). This approach simplifies the selection of appropriate films for soil fumigation by providing rapid, reproducible, and precise measurements of their permeability to specific fumigants and application conditions. Scientists from the Oregon Agricultural Experiment Station (Corvallis) evaluated the effectiveness of adapted and native woody plant species as drift barriers between cherry orchards and surface water resources in Wasco County (Middle Columbia-Hood Subbasin), Oregon. Wasco County contains nearly 9,000 acres of cherry orchards. Pest management includes the use of organophosphate insecticides, applied by airblast ground sprayers. A site along Mill Creek was chosen based on prevailing wind direction and riparian vegetation. Two sampling areas along the creek were selected - an area with riparian vegetation between the orchard and the creek and an area without riparian vegetation. Spray deposition samplers consisted of nylon screens (23 x 26 cm), attached to rectangular aluminum frames. At each location a sampler was positioned horizontally at a height just above the orchard tree canopy, at approximately 5 meters. Four samplers were located along two transects extending from within the orchard towards the creek. For one transect the sampler at the creek was intercepted by riparian vegetation and the other was not. The ground trials were conducted in a simulated creek scenario approximately 5 meters from Mill Creek. The distance between the edge of the simulated creek and the pear orchard was 20 meters. Two types of sprayers were evaluated: the Accutech Orchard Tower sprayer (Blueline Manufacturing Company Inc, Moxee, WA) and the standard air blast sprayer (Air-O-Fan, Reedley, CA). In addition, the air blast sprayer was operated both normally and modified with a plywood doughnut affixed to the rear of the sprayer. The doughnut restricts air intake (cut to reduce the area of the fan by half) to reduce airflow through the sprayer, resulting in a reduction in drift. Deposition data suggest that riparian vegetation was generally effective in reducing deposition near the creek for applications using the Accutech sprayer. Results for the Air-O-fan were inconclusive. Constructed wetlands (CWs), along with other vegetative systems, are increasingly being promoted as a mitigation practice to treat non-point source runoff to rid contaminants such as pesticides. However, studies so far have mostly focused on demonstrating contaminant removal efficiency. In this study, using two operational CWs located in the Central Valley of California, we explored the mechanisms underlying the removal of pyrethroids and chlorpyrifos from agricultural runoff water, and further evaluated the likelihood for the retained pesticides to accumulate within the CWs over time. In the runoff water passing through the CWs, pyrethroids were associated overwhelmingly with suspended solids >0.7 ¼m, and the sorbed fraction accounted for 62-93% of the total concentrations. The derived Kd values for the suspended solids were in the order of 104-105, substantially greater than those reported for bulk soils and sediments. Distribution of pyrethroids in the wetland sediments was found to mimic organic carbon distribution, and was enriched in large particles that were partially decomposed plant materials, and clay-size particles (<2 ¼m). Retention of suspended particles, especially the very large particles (>53 ¼m) and the very fine particles, is thus essential in removing pyrethroids and chlorpyrifos in CWs. Under flooded and anaerobic conditions, most pyrethroids and chlorpyrifos showed moderate persistence. However, the retained pyrethroids were very stable in dry and aerobic sediments between irrigation seasons, suggesting a possibility for accumulation over time. Therefore, the long-term ecological risks of CWs should be further understood before their wide adoption. Scientists in Beltsville, MD, evaluated water quality in the Choptank River estuary, a tributary of the Chesapeake Bay that since 1998 has been classified as impaired waters under the Federal Clean Water Act. Multiple water quality parameters (salinity, temperature, dissolved oxygen, chlorophyll a) and analyte concentrations (nutrients, herbicide and herbicide degradation products, arsenic, and copper) were measured at seven sampling stations in the Choptank River estuary. Samples were collected under base flow conditions in the basin on thirteen dates between March 2005 and April 2008. As commonly observed, results indicate that agriculture is a primary source of nitrate in the estuary and that both agriculture and wastewater treatment plants are important sources of phosphorus. Concentrations of copper in the lower estuary consistently exceeded both chronic and acute water quality criteria, possibly due to use of copper in antifouling boat paint. Concentrations of copper in the upstream watersheds were low, indicating that agriculture is not a significant source of copper loading to the estuary. Concentrations of herbicides (atrazine, simazine, and metolachlor) peaked during early-summer, indicating a rapid surface-transport delivery pathway from agricultural areas, while their degradation products (CIAT, CEAT, MESA, and MOA) appeared to be delivered via groundwater transport. Some in-river processing of CEAT occurred, whereas MESA was conservative. This work provides a baseline against which to compare future changes in water quality and may be used to design future monitoring programs needed to assess restoration strategy efficacy. The anodic Fenton treatment method (AFT) has been successfully applied to the removal of Ciprofloxacin (CIP), a widely used fluoroquinolone antibiotic, from aqueous solution. Degradation kinetics were found to be species dependent. At initial pH 3.2, CIP remained in its cationic form and the kinetics followed a previously developed AFT model. At an initial near-neutral pH, CIP speciation changed during the degradation, due to pH changes over the process, and no obvious model fit the data. Density functional theory (DFT) calculations indicated a protonated species-dependent reaction affinity toward hydroxyl radicals. Scientists from Cornell University (Ithaca, NY) derived a new model based on the AFT model with the addition of species distribution during the degradation, and it was shown to describe the degradation kinetics successfully. Degradation of reference compounds further confirmed that the free carboxylic acid group, which contributes to the species changes, plays a key role in the observed degradation pattern. Furthermore, degradation of reference CIP-metal complexes confirmed that the formation of these complexes does not have a major effect on the degradation pattern. By the end of the AFT treatment, neither CIP nor its degradation products were detected, indicating successful removal of antibacterial properties. Objective 3: Determine adverse impacts from agrochemical exposure to cells, organisms, and ecosystems. Proteomics has gained popularity in the field of ecotoxicology as a holistic tool for unraveling novel mechanisms of toxicity. The holo-artic amphipod Diporeia spp. is declining at precipitous rates in the Great Lakes. Scientists from Purdue University (West Lafayette, Indiana) evaluated the use of the well studied amphipod model Hyalella azteca as a surrogate for Diporeia. A proteomics approach determined whether these two species of amphipods responded similarly to the same chemicals (atrazine, ATZ, and one of its metabolites, desethylatrazine, DEA) and enhanced the understanding of the mechanisms of toxicity of ATZ and DEA in aquatic invertebrates. Disruption in energy production and mitochondrial function was observed. Proteins associated with hormonal disruptions in vertebrates were identified, suggesting potential endocrine disruption. In addition, H. azteca and Diporeia spp. responded with similar proteomic profiles after ATZ and DEA exposure suggesting that H. azteca may be used as a surrogate model organism for Diporeia spp. The impact of non-lethal agrochemical/environmental exposures on non-target avian species are difficult to access particularly in terms of developing Natural Resource Damage Assessments (NRDA). Scientists from the University of Neveda (Reno) used a homing pigeon model developed at UNR for assessing the impact of environmental exposures of methylmercury on flight time of avian species. During the control and dosed flight studies, water consumption, temperature and humidity were monitored on a daily basis in order to determine the relationship between these parameters. The data show that flight activity, temperature and humidity impact water consumption rates in these birds and need to be considered when developing NRDAs. Flight time effects from methylmercury exposure are currently being assessed. Objective 4: Develop technologies that mitigate adverse human and environmental impacts. Pesticides associated with the turfgrass industry have been detected in storm runoff and surface waters of urban watersheds; invoking concern of their potential environmental effects and a desire to reduce their transport to non-target locations. Scientists from St. Paul, MN, quantified levels of chlorpyrifos, dicamba, dimethylamine salt of 2,4-dichlorophenoxyacetic acid (2,4-D), flutolanil, and mecoprop-p (MCPP) transported in runoff from bentgrass (Agrostis palustris) fairway turf managed with solid tine (ST) or hollow tine (HT) core cultivation to determine which cultivation practice is more efficient at mitigating environmental risk. Plots receiving HT core cultivation showed a 10% and 55% reduction in runoff volume and a 15 to 57% reduction in pesticide transport with runoff at 63 d and 2 d following core cultivation. Estimated environmental concentrations of the pesticides in a surface water receiving runoff from turf managed with ST core cultivation exceeded the median lethal concentration (LC50) or median effective concentration (EC50) of nine aquatic organisms evaluated. Replacing ST core cultivation with HT core cultivation reduced surface water concentrations of the pesticides to levels below the LC50 and EC50 for most these aquatic organisms. Results of this research provide quantitative information that will allow for informed decisions on cultural practices that can maximize pesticide retention at their site of application; improving pest control in turf while minimizing environmental contamination and adverse effects associated with the off-site tranpsort of pesticides. The north shore of Lake Apopka, located near Orlando, FL, is heavily contaminated with various agrochemicals. These muck soils are roughly 40% organic matter and 40% water with a large capacity for storing nutrients and pesticides. Some of the organochlorine compounds such as DDT and its metabolites, DDD and DDE, have contaminated the soil from the last time DDT was applied over thirty years ago. Scientists from the University of Florida (Gainesville) discovered that two wood-rot fungi, Phenarochaete chrysosporium and an indigenous Nectrai species, are equally effective in remediating the soil, once the proper conditions are met. In four months, the concentration of p,p-DDT for the 0 3 inch (0 - 8 cm) depth declined by 65.3, 57.8% and 53.3% when the surface of the mesocosm soil was sprinkled weekly with 3.3 liters of P. chrysosporium rinse, or Nectria sp.rinse or tap water only, respectively. The tap water treatment was hypothesized to be effective due to a >50% reduction in soil nitrate, a known inhibitor of extracellular enzyme production by wood-rot fungi. The extracellular enzymes allowed the indigenous Nectria species to actively remediate DDT, DDE, and DDD in situ. The United States has been using pyridostigmine bromide (PB) as a prophylactic to the toxic effects of soman, a potent chemical warfare agent, since the first Gulf War. Scientists from the University of California (Davis) and colleagues showed that PB protected a significant percentage of human intercostal muscle AChE in vitro. They reported that inhibition of bovine red blood cell (RBC) AChE is similarly protected by PB from several organophosphates (OP) pesticides including chlorpyrifos oxon, diazinon oxon, paraoxon and DFP but AChE inhibition from malaoxon was not given the conditions of the study. Even though bovine RBC AChE is similar in its properties to human AChE, further study is needed of the extent of protective effect of PB on pesticides and human AChE. The findings suggest that pretreatment with PB might be of use in protecting growers and farmworkers from the effects of selected pesticides in the absence of protective clothing and to the public, in general, in the event of terrorist attacks. Biofuel crops can potentially be grown on arid lands that do not compete with other food and feed crops. Grindelia squarrosa, commonly known as gumweed, is a flowering plant species common to Nevada that is found in many areas of the inter-mountain west, particularly along roadsides where increased precipitation is available from runoff. A preliminary analysis of numerous desert plants by Lemaire in 1982 (unpublished) singled out gumweed as a strong candidate for crude oil production. High oil yield per acre, along with minimal watering requirements, makes gumweed a strong crop for biodiesel production in the western United States. Scientists from the University of Nevada (Reno) reported that processed gumweed provides an average of 12-23 % crude oil by dry weight, depending on the plant stand collected and the method of sample drying. While the majority of hydrocarbons present in the extracts are at the heavy end of diesel fuel, a derivatized B20 blended biodiesel was shown to meet ASTM standards for flash point, kinematic viscosity, and sulfur content. Gumweed biodiesel blends offer a useful source of additional fuel that can be produced from crops grown in arid environments with minimal irrigation needs, while reducing the competition between food and biofuel crops. No additional engine modifications are needed for the use of B5 or B20 biofuels.