2 research outputs found
Enhanced Accessibility of Polycyclic Aromatic Hydrocarbons (PAHs) and Heterocyclic PAHs in Industrially Contaminated Soil after Passive Dosing of a Competitive Sorbate
To
assess the exposure to polycyclic aromatic hydrocarbons (PAHs) it
is important to understand the binding mechanisms between specific
soil constituents and the organic pollutant. In this study, sorptive
bioaccessibility extraction (SBE) was applied to quantify the accessible
PAH fraction in industrially contaminated soil with and without passive
dosing of a competitive sorbate. SBE experiments revealed an accessible
PAH fraction of 41 ± 1% (∑16 US EPA PAHs + 5 further PAHs).
The passive dosing of toluene below its saturation level revealed
competitive binding and resulted in an average increase of the accessible
fraction to 49 ± 2%, whereby primarily the accessibility of higher
molecular weight PAHs (log <i>K</i><sub>ow</sub> > 6)
was affected. Competitive binding was verified using the same soil
with only desorption-resistant PAHs present. In this experiment, passive
dosing of toluene resulted in desorption of 13 ± 0.4% PAH. We
explain increased PAH desorption after addition of toluene by competitive
adsorption to high-affinity sorption sites while acknowledging that
toluene could additionally have increased PAH mobility within the
soil matrix. Findings suggest that the presence of copollutants at
contaminated sites deserves specific considerations as these may increase
accessibility and thereby exposure and mobility of PAHs