Polycyclic aromatic hydrocarbons in stormwater runoff from sealcoated pavements.
Coal-tar based sealcoat has been identified as a source of polycyclic aromatic hydrocarbons (PAHs) in the environment. This study measured the long-term release of PAHs in parking lot runoff and found that the presence of coal tar sealant increased the mass of PAHs released in runoff by over an order of magnitude. PAH concentrations in stormwater from two coal tar sealed parking lots and one unsealed parking lot (control) were monitored over a two-year period. The measured flow volume and concentrations were used to calculate a mass of 9.8-10.8 kg total Σ16 PAHs per hectare exported in stormwater runoff from the two sealed parking lots and 0.34 kg total Σ16 PAHs per hectare from the unsealed control. The study also measured sediment PAH concentration changes in a receiving drainage and found that even partial coverage of a drainage area by coal tar sealant resulted in measurable increases in PAH sediment concentrations; PAH concentrations in sediment in a stormwater swale receiving runoff from both sealed and unsealed lots increased near the outfall from less than 4 mg/kg prior to sealing to 95.7 mg/kg after sealing. Compound ratio plots and principal components analysis were examined and were able to clearly differentiate between pre- and postsealant samples.
University of New Hampshire, 35 Colovos Road, Durham, New Hampshire 03856, United States. alison.watts@unh.edu
Alison W
AW
Watts
Thomas P
TP
Ballestero
Robert M
RM
Roseen
James P
JP
Houle
D003033:Coal Tar / Q000032:analysis*; D003252:Construction Materials; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D011891:Rain / Q000737:chemistry*; D014186:Transportation; D014874:Water Pollutants, Chemical / Q000032:analysis*
D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D003033:Coal Tar