title: Sorption and leaching of benzalkonium chlorides in agricultural soils.
abstract: The adsorption and leaching characteristics of two commonly used benzalkonium chlorides (BACs), benzyl dimethyl dodecyl ammonium chloride (BDDA) and benzyl dimethyl tetradecyl ammonium chloride (BDTA) using three agricultural soils with varied proportions of silt, sand, clay, and organic matter were determined. BACs are cationic surfactants used in large quantities for sanitary and personal care products and are abundant in environmental samples. Adsorption isotherm data (aqueous concentration in the range of 25-150 mg L-1) fitted the Langmuir model better than the Freundlich model. BDTA with a longer alkyl chain adsorbed more to soil compared to BDDA, and the soil with the highest percentage of clay adsorbed the most. Column tests conducted using soils amended with lime stabilised biosolids and artificial rain water at a flow rate of 0.2 mL min-1indicate very low leaching of BACs. Less than 1% of the available BDDA leached through sandy loam soil column with a depth of 9 cm. Therefore, the possibility of BACs to become bioavailable through leaching is very low at environmentally relevant concentrations.
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON N6A 5B9, Canada.
authors.forename: Adnan Hossain
authors.initials: AH
authors.lastname: Khan
authors.affiliation: Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada.
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Macfie
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON N6A 5B9, Canada. Electronic address: mray@eng.uwo.ca.
authors.forename: Madhumita B
authors.initials: MB
authors.lastname: Ray
mesh_terms: D000327:Adsorption; D000383:Agriculture; D001548:Benzalkonium Compounds; D012987:Soil; D012989:Soil Pollutants
chemical_list: D001548:Benzalkonium Compounds; D012987:Soil; D012989:Soil Pollutants
keywords: Adsorption isotherm models; Adsorption on agricultural soil; Benzalkonium chlorides; Biosolids; Soil column leaching