Occurrence and distribution of PAHs in rainwater and urban runoff

Abstract

Sixteen polycyclic aromatic hydrocarbons (PAHs) were measured in dissolved and particulate phases of Singapore rainwater and stormwater for the first time. The extraction of dissolved PAHs was performed using solid-phase microextraction (SPME), while that of particulate bound PAHs was done by microwave assisted extraction (MAE). The quantification of PAHs in aqueous samples was performed using the GC-MS technique. In the rainwater, more PAHs were associated with dissolved phase, while in the stormwater PAHs were mainly associated in particulate phase. The I#PAH concentrations in rainwater (dissolved and particulate phases) were 2,408 A? 899 ng/l, 1,847 A? 414 ng/l respectively, while those in stormwater were 1,143 A? 498 ng/l, 8,164 A? 3,063 ng/l, respectively. A temporal variability in PAHs concentrations in rainwater was noticed with higher concentrations in October, coinciding with the largest precipitation intensity. The statistical analysis of PAHs signatures in rainwater and stormwater indicates that traffic related activities are the main source of PAHs found in the water samples.