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Publications: 2012

Papers & ReportsIndustrial and Specialty Chemicals2012

TFA FROM HFO-1234yf: ACCUMULATION AND AQUATIC RISK IN TERMINAL WATER BODIES

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A next-generation mobile automobile air-conditioning (MAC) refrigerant, HFO-1234yf (CF3CF¼CH2), is being developed with improved environmental characteristics. In the atmosphere, it ultimately forms trifluoroacetic acid (TFA(A); CF3COOH), which is subsequently scavenged by precipitation and deposited on land and water as trifluoroacetate (TFA; CF3COO-). Trifluoroacetate is environmentally stable and has the potential to accumulate in terminal water bodies, that is, aquatic systems receiving inflow but with little or no outflow and with high rates of evaporation. Previous studies have estimated the emission rates of HFO-1234yf and have modeled the deposition concentrations and rates of TFA across North America. The present study uses multimedia modeling and geographic information system (GIS)-based modeling to assess the potential concentrations of TFA in terminal water bodies over extended periods. After 10 years of emissions, predicted concentrations of TFA in terminal water bodies across North America are estimated to range between current background levels (i.e., 0.01–0.22 mg/L) and 1 to 6 mg/L. After 50 years of continuous emissions, aquatic concentrations of 1 to 15 mg/L are predicted, with extreme concentrations of up to 50 to 200 mg/L in settings such as the Sonoran Desert along the California/Arizona (USA) border. Based on the relative insensitivity of aquatic organisms to TFA, predicted concentrations of TFA in terminal water bodies are not expected to impair aquatic systems, even considering potential emissions over extended periods.

Russell, M. H., Hoogeweg, G., Webster, E. M., Ellis, D. A., Waterland, R. L. and Hoke, R. A. (2012), TFA from HFO-1234yf: Accumulation and aquatic risk in terminal water bodies. Environmental Toxicology and Chemistry, 31: 1957–1965. doi: 10.1002/etc.1925

Papers & ReportsCrop Protection2012

Development of a Spatial-Temporal Co-occurrence Index To Evaluate Relative Pesticide Risks to Threatened and Endangered Species

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A decline in pelagic species has been observed in the San Francisco Bay-Delta, triggering questions as to whether contaminants are contributing to the decline. An index method was developed to evaluate the spatial and temporal co-occurrence of pesticides and threatened and endangered species for this large ecosystem. The co-occurrence index combines monthly species abundance with statistical distributions of pesticide indicator days for 40 widely used pesticides. The frequency of co-occurrence was determined for 12 aquatic and semi-aquatic threatened or endangered species to help guide future research and monitoring priorities, and the placement of best management practices in the study area.

Hoogeweg, C.G., D.L. Denton, R. Breuer, W.M. Williams, and P. TenBrook. 2012. Development of a Spatial-Temporal Co-occurrence Index To Evaluate Relative Pesticide Risks to Threatened and Endangered Species. Pesticide Regulation and the Endangered Species Act. ACS Symposium Series, Vol. 1111, Chapter 22, pp 303–323.

(Chapter reprinted with permission from Pesticide Regulation and the Endangered Species Act. Kenneth D. Racke, Bernalyn D. McGaughey, James L. Cowles, A. Tilghman Hall, Scott H. Jackson, Jeffrey J. Jenkins, John J. Johnston (Editors). Volume 1111. November 6, 2012. DOI: 10.1021/bk-2012-1111. Copyright 2012 American Chemical Society.)

PostersWater/Wastewater Assessments2012

Prioritizing Research Needs for Threatened and Endangered Species in California Watersheds

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A decline in pelagic species in the San Francisco Bay Delta region has led to speculation as to whether contaminants may be playing a role. A weight-of-evidence analysis was conducted to rank the relative risk potential for pesticides to impact threatened or endangered species in the Sacramento River, San Joaquin River, and Bay-Delta estuary watersheds. The study utilized monitoring data, simulation modeling, and GIS to address the co-occurrence of 40 widely used herbicides, fungicides, and insecticides to 12 aquatic and semi-aquatic species, including Chinook Salmon (Oncorhynchus tshawytscha), Central Valley steelhead (O. mykiss), southern North American Green Sturgeon (Acipenser medirostris), Delta smelt (Hypomesus transpacificus), Striped Bass (Morone saxatilis), San Francisco Longfin Smelt (Spirinchus thaleichthys), Threadfin Shad (Dorosoma petenense), California Red-legged Frog (Rana draytonii), and the California Freshwater Shrimp (Syncaris pacifica). Pesticide application sites represented in model simulations included fruit, vegetable, grain, nuts, rice, landscape maintenance, and structural applications. Daily pesticide concentrations were predicted at the PLSS section level from runoff, erosion, and drift sources. An co-occurrence matrix approach was developed to evaluate the spatial and temporal co-occurrence of pesticides and species. Areas of highest potential concern were located along the main branch of the Sacramento River, the northern part of the Delta region, and the southern part of the Delta in San Joaquin County. A few small clusters of high co-occurrence values were predicted along the Sacramento River Deep Water Ship Channel and in southern Butte County along the Feather River. Monitoring is sparse in a number of these and lesser areas of potential concern. The results of this study can be used to support current and future monitoring programs by strategic placement of sampling locations and frequency. Ultimately, it is hoped that this project will improve decision making and optimize resource spending of groups seeking to improve the long-term sustainability of these aquatic habitats.

Breuer, R., D. Denton, W.M. Williams, C.G. Hoogeweg and M. Zhang. Prioritizing Research Needs for Threatened and Endangered Species in California Watersheds.

Papers & ReportsAgriculture and Food2012

TFA From HFO-1234yf: Accumulation and Aquatic Risk in Terminal Water Bodies

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A next-generation mobile automobile air-conditioning (MAC) refrigerant, HFO-1234yf (CF3CF = CH2), is being developed with improved environmental characteristics. In the atmosphere, it ultimately forms trifluoroacetic acid (TFA(A); CF3COOH), which is subsequently scavenged by precipitation and deposited on land and water as trifluoroacetate (TFA; CF3COO-). Trifluoroacetate is environmentally stable and has the potential to accumulate in terminal water bodies, that is, aquatic systems receiving inflow but with little or no outflow and with high rates of evaporation. Previous studies have estimated the emission rates of HFO-1234yf and have modeled the deposition concentrations and rates of TFA across North America. The present study uses multimedia modeling and geographic information system (GIS)-based modeling to assess the potential concentrations of TFA in terminal water bodies over extended periods. After 10 years of emissions, predicted concentrations of TFA in terminal water bodies across North America are estimated to range between current background levels (i.e., 0.01–0.22 µg/L) and 1 to 6 µg/L. After 50 years of continuous emissions, aquatic concentrations of 1 to 15 µg/L are predicted, with extreme concentrations of up to 50 to 200 µg/L in settings such as the Sonoran Desert along the California/Arizona (USA) border. Based on the relative insensitivity of aquatic organisms to TFA, predicted concentrations of TFA in terminal water bodies are not expected to impair aquatic systems, even considering potential emissions over extended periods. Environ. Toxicol. Chem. 2012; 31: 1957–1965. © 2012 SETAC

Russell, M.H., C.G. Hoogeweg, E.M. Webster, D.A. Ellis, R.L. Waterland, and R.A Hoke.. 2012. TFA from HFO-1234yf: Accumulation and aquatic risk in terminal water bodies. Environmental Toxicology and Chemistry. doi: 10.1002/etc.1925.

Papers & ReportsHome and Personal Care Products2012

Estimating Chemical Emissions From Home and Personal Care Products in China

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China’s economy has grown significantly and concomitantly so has the demand for home and personal care (HPC) products. The detection of chemicals used in HPC products is increasing in profile as China strives to improve its environmental management. China is developing robust exposure models for use in regulatory risk-based assessments of chemicals, including those chemicals used in HPC products. Accurate estimates of chemical emissions play an important role within this. A methodology is presented to derive spatially refined emissions from demographic and economic indicators with large variations in emissions calculated, showing product usage being higher in East and South China. The less affordable a product, the greater the influence per capita Gross Domestic Product has on the product distribution. Lastly, more spatially resolved input data highlights greater variation of product use. Linking product sales data with population density increased the observed variability in absolute usage distribution of HPC products at the county > province > regional > country scale.

“Estimating chemical emissions from Home and Personal Care products in China” Environmental Pollution 165: 199-207. 2012. (J. Hodges, C.M. Holmes, R. Vamshi, D. Mao and O. Price)