title: Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.
abstract: Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference.
authors.affiliation: Department of Chemistry, University of Otago , Dunedin 9016, New Zealand.
authors.forename: Cleo L
authors.initials: CL
authors.lastname: Davie-Martin
authors.affiliation: Department of Chemistry, University of Otago , Dunedin 9016, New Zealand.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Hageman
authors.affiliation: School of Earth Sciences, The Ohio State University , Columbus, Ohio 43210, United States.
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Chin
authors.affiliation: Department of Chemistry, University of Otago , Dunedin 9016, New Zealand.
authors.forename: Valentin
authors.initials: V
authors.lastname: Rougé
authors.affiliation: Department of Mathematics and Statistics, University of Otago , Dunedin 9016, New Zealand.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Fujita
mesh_terms: D000388:Air; D006813:Humidity; D007753:Laboratories; D016014:Linear Models; D008962:Models, Theoretical; D010575:Pesticides / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis; D013696:Temperature; D014835:Volatilization
chemical_list: D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants