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Chemical fate and transport in a domestic septic system: Sorption and transport of anionic and cationic surfactants
Author(s) -
McAvoy D.C.,
White C.E.,
Moore B.L.,
Rapaport R.A.
Publication year - 1994
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620130205
Subject(s) - sorption , ammonium , aquifer , environmental chemistry , chemistry , total organic carbon , ammonium chloride , groundwater , environmental science , geology , geotechnical engineering , organic chemistry , adsorption
The sorption and transport of linear alkylbenzene sulfonate (LAS) and dialkyl quaternary ammonium compounds [ditallow dimethyl ammonium chloride (DTDMAC) and distearyl dimethyl ammonium chloride (DSDMAC)] were determined within the upper soil horizons and in the aquifer below a septic tank tile field at a study site in Ontario. Sorption of LAS was greatest immediately below the tile field ( K d = 17 L/kg) within the upper unsaturated soil horizons and lowest in the aquifer ( K d = 1 L/kg). LAS sorption appeared to be controlled by a hydrophobic mechanism and was positively correlated with the organic carbon ( r = 0.9) and the clay content ( r = 0.9) in the subsurface environment. The sorption of DTDMAC/DSDMAC ( K d = 25‐62 L/kg) was an order of magnitude higher than LAS but showed no trend throughout the subsurface environment. The retention of DTDMAC/DSDMAC was believed to be by ion exchange within the clay interlayer basal spaces. Samples collected from the field showed concentrations of DTDMAC to range from approximately 60 mg/kg in the tile field gravel to <2 mg/kg within 10 cm of soil below the tile field gravel. Concentrations of LAS were approximately 20 mg/kg in the tile field gravel and diminished to < 1 mg/kg within 5 cm of soil below the tile field gravel. Soil solution and aquifer concentrations of LAS were always <50 μg/L and usually below the detection limit of 10 μg/L in the aquifer. Concentrations of DTDMAC in the aquifer were below the limit of detection (4 μg/L). Mathematical calculations illustrated the importance of biodegradation and sorption as removal mechanisms of these materials in subsurface environments.