Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

摘要

The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution of low-molecular weight PAHs (LMW PAHs), middle-molecular weight PAHs (MMWPAHs) and high-molecularweight PAHs (HMWPAHs) among the fractions was also evaluated. The results from the synthetic suspensions showed that the highest concentrations of the PAHs were found in the Filtrated fractions and, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples N50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMWPAHs was highest in the Particulate fractions (particles N 0.7 μm). The highest concentration of PAHs in the Colloidal fraction was found in the sample with occurrence of small nano-sized particles (b10 nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. © 2015 Elsevier B.V. All rights reserved.