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Toose L.,LTEC | Warren C.,ExxonMobil | Mackay D.,Trent University | Parkerton T.,ExxonMobil | And 6 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015

Components of emulsifiable concentrates (ECs) used in pesticide formulations may be emitted to air following application in agricultural use and contribute to ozone formation. A key consideration is the fraction of the ECs that is volatilized. This study is designed to provide a mechanistic model framework for estimating emissions of an aromatic hydrocarbon fluid used in ECs based on the results of spray chamber experiments that simulate fate as the fluids become subject to volatilization, sorption to soil, and biodegradation. The results indicate the need to treat the volatilization losses in three stages: (i) losses during spraying, (ii) losses up to 12 h after spraying in which the soil is coated with the ECs, and (iii) subsequent longer term losses in which the ECs become increasingly sorbed and subject to biodegradation. A mass balance model, the agrochemical derived volatile organic compound air transfer evaluation (ADVOCATE) tool, is developed, treating the ECs as seven hydrocarbon component groups, to estimate the volatilization and biodegradation losses using parameters fitted to empirical data. This enables losses to be estimated for each hydrocarbon component under field conditions, thereby providing a basis for improved estimation of ozone formation potential and for designing ECs that have lower emissions. © 2015 American Chemical Society. Source


Redman A.D.,ExxonMobil | Parkerton T.F.,ExxonMobil | Paumen M.L.,ExxonMobil | Mcgrath J.A.,HDR | And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2014

Substance risk assessments require estimation of predicted no-effect concentrations (PNECs) in soil and sediment. The present study applies the target lipid model (TLM) and equilibrium partitioning (EqP) model to toxicity data to evaluate the extrapolation of the TLM-derived aquatic PNECs to these compartments. This extrapolation assumes that the sensitivity of aquatic species is similar to that of terrestrial and benthic species. The acute species sensitivity distribution, expressed in terms of species-specific critical target lipid body burdens, was computed using the TLM-EqP framework and found to span a similar range as the aquatic organism species sensitivity distribution but with a slightly lower median value (less than 2 times). The species sensitivity distribution for acute-to-chronic ratios also exhibited a similar range and distribution across species, suggesting similar mechanisms of action. This hypothesis was further tested by comparing empirical soil/sediment chronic effect levels to the calculated PNEC derived using TLM-EqP. The results showed that 95% of the compiled chronic effects data fell above the PNEC, confirming an adequate protection level. These findings support the conclusion that TLM-derived aquatic PNECs can be successfully extrapolated to derive credible PNECs for soil and sediment compartments. © 2014 SETAC. Source


Leonards P.E.,VU University Amsterdam | Postma J.F.,Grontmij AquaSense | Comber M.,ExxonMobil | Whale G.,Royal Dutch Shell | Stalter G.,CONCAWE
Environmental Toxicology and Chemistry | Year: 2011

Whole effluent assessments (WEA) are being investigated as potential tools for controlling aqueous industrial discharges and minimizing environmental impact. The present study investigated how toxicity and the presence of potentially bioaccumulative substances altered when refinery effluents were subjected to biodegradation tests. Three petrochemical effluents were assessed, two freshwater and one saline, and subjected to two different types of biodegradation tests, resembling either a ready style (dissolved organic carbon (DOC)-die away) or an inherent style (Zahn-Wellens) test and the toxicity and potential to bioaccumulate parameters were re-analysed during and after biodegradation. A high proportion of the potentially bioaccumulative substances (PBS) in these effluents was easily biodegradable. Biodegradation not only lowered the PBS concentration but also toxicity. Appropriate controls are required however, as some increases in toxicity were observed after 4h. In the present study, six other petrochemical effluents were also assessed for their PBS content and toxicity to increase the understanding of the relationship between PBS and toxicity. The results showed that the PBS concentrations in these samples were lower than the estimated benchmarks of acute toxicity for algae, fish and crustacean, although two samples were above the critical PBS values for chronic narcotic toxicity for Daphnia magna, which support the assumption that narcotic effects are mainly responsible for the observed toxicity in refinery effluents. It can be concluded that for facilities processing petroleum products that the measurement of PBS is a suitable surrogate for toxicity tests at the screening stage. Finally, the combination of persistency, bioaccumulation, and toxicity tests was shown to have additional value compared to an approach using only toxicity tests. © 2011 SETAC. Source


Daines K.,Arcadis | Dow R.,Arcadis | Lethbridge G.,Royal Dutch Shell | Smith J.W.N.,Royal Dutch Shell | And 2 more authors.
Quarterly Journal of Engineering Geology and Hydrogeology | Year: 2011

Releases of hydrocarbon-based fuels at retail filling stations have the potential to affect soil and groundwater and are listed by the European Commission as a potential pressure on achievement of the Water Framework Directive's water quality objectives. This paper presents an analysis of the environmental sensitivity of retail filling station locations across Europe, with regard to proximity to groundwater, surface water and ecological receptors. A geographic information system-based approach was used to map the location of nearly 86 000 retail filling station sites to zones of differing environmental sensitivity. The results indicate that the environmental sensitivity of retail filling stations is highly variable, and that only a relatively small proportion has the potential to cause impact on groundwater abstractions, surface water or to designated ecological receptors. Accordingly, a sitespecific risk-based approach to the design and operation of retail filling stations provides the most proportionate and sustainable basis for their management. In addition, the research provides a tool for both single retail filling station operators and the oil industry as a whole to identify areas of higher environmental sensitivity, encouraging the focusing of investment in preventive measures where it is most needed. © 2011 Geological Society of London. Source


Redman A.D.,ExxonMobil | Parkerton T.F.,ExxonMobil | Paumen M.L.,ExxonMobil | Eadsforth C.V.,Royal Dutch Shell | And 4 more authors.
Integrated Environmental Assessment and Management | Year: 2014

PETRORISK is a modeling framework used to evaluate environmental risk of petroleum substances and human exposure through these routes due to emissions under typical use conditions as required by the European regulation for the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Petroleum substances are often complex substances comprised of hundreds to thousands of individual hydrocarbons. The physicochemical, fate, and effects properties of the individual constituents within a petroleum substance can vary over several orders of magnitude, complicating risk assessment. PETRORISK combines the risk assessment strategies used on single chemicals with the hydrocarbon block approach to model complex substances. Blocks are usually defined by available analytical characterization data on substances that are expressed in terms of mass fractions for different structural chemical classes that are specified as a function of C number or boiling point range. The physicochemical and degradation properties of the blocks are determined by the properties of representative constituents in that block. Emissions and predicted exposure concentrations (PEC) are then modeled using mass-weighted individual representative constituents. Overall risk for various environmental compartments at the regional and local level is evaluated by comparing the PECs for individual representative constituents to corresponding predicted no-effect concentrations (PNEC) derived using the Target Lipid Model. Risks to human health are evaluated using the overall predicted human dose resulting from multimedia environmental exposure to a substance-specific derived no-effect level (DNEL). A case study is provided to illustrate how this modeling approach has been applied to assess the risks of kerosene manufacture and use as a fuel. © 2014 SETAC. Source

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