Abstract

Different methods to quantify soil porewater concentrations of contaminants will provide different types of information. Passive sampling measurements give freely dissolved porewater concentrations (C-pw,C-free), while leaching tests provide information on the mobile concentration (C-pw,C-leach), including contaminants associated with dissolved organic carbon (DOC) and particles/colloids in the porewater. This study presents a novel combination of these two measurements, to study the sorption and mobility of polycyclic aromatic compounds (PACs) to DOC and particulate organic carbon (POC) in 10 historically contaminated soils. The PACs investigated were polycyclic aromatic hydrocarbons (PAHs), oxygenated-PAHs, and nitrogen containing heterocyclic PACs. Observed C-pw,C-leach was up to 5 orders of magnitude higher than C-pw,C-free; implying large biases when C-pw,C-leach is used to assess bioavailability or soil partitioning. Sorption of PACs to DOC and POC was important for the mobility of compounds with log K-OW > 4. Average DOC/water-partitioning coefficients (K-DOC) correlated well with KOW (log K-DOC = 0.89 x log K-OW +1.03 (r(2) = 0.89)). This relationship is likely more accurate for historically contaminated soils than previously published data, which suffer from artifacts caused by problems in measuring C-pw,C-free correctly or not using historically contaminated soils. POC/water-partitioning coefficients (K-POC) were orders of magnitude larger than corresponding K-DOC, suggesting sorption to mobile particles/colloids is the dominant mechanism for PAC mobility.

Published in

Environmental Science and Technology
2016, Volume: 50, number: 21, pages: 11797-11805
Publisher: AMER CHEMICAL SOC

SLU Authors

• Josefsson, Sarah

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Geological Survey of Sweden (SGU)

• Berggren Kleja, Dan

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • Swedish Geotechnical Institute (SGI)

UKÄ Subject classification

Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1021/acs.est.6b02774

Permanent link to this page (URI)

https://res.slu.se/id/publ/83250