Characterizing the Semi-Volatile Organic Compounds in Runoff from Roads and Other Impervious Surfaces in a Suburban Area of Beijing

Abstract

Stormwater runoff samples were collected from five different land use sites (gas station, city road, campus, park, and residential) in a precipitation event on May 22nd, 2017, from a small suburban area (5 km × 2 km) of the city of Beijing, China. There were 72 types of semi-volatile organic compounds (SVOCs) found in these runoff samples, including 33 types of monocyclic aromatic hydrocarbons (MAHs), 22 types of polycyclic aromatic hydrocarbons (PAHs), 6 types of phthalate esters (PAEs), 9 types of pesticides and 2 types of polychlorinated biphenyls (PCBs). Especially, 26 types of SVOCs (7 MAHs, 9 PAHs, 5 PAEs, and 5 pesticides) were detected in all water samples. SVOCs concentrations were higher in the samples from gas station and city road, and lower in runoff from campus, park and residential sites. The change in the ratio of anthracene to anthracene plus phenanthrene (ANT/(ANT + PHE)) in this study, reflected the importance of PAH source and land use. Di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate, are two of the phthalate esters 100% detected in the runoff samples. The city road runoff DEHP concentrations recorded the highest values (> 6000 ng/L), however, were still less than those wastewater DEHP pollutants measured in developed countries (e.g. UK, Canada, Finland, etc.). One-way ANOVA analysis in this study, showed that land use could significantly influence 23 SVOCs in the runoff samples, whereas the runoff SVOCs in different precipitation period showed no statistical changes in the five sites, and presented a general temporal trends "high (beginning)-low (middle period)-little raising (ending)". The findings in this study could be used in municipal management of wastewater collection and treatment.