The contribution of particles washed from rooftops to contaminant loading to urban streams

Abstract

Rooftops are both a source of and a pathway for contaminated runoff in urban environments. To investigate the importance of particle-associated contamination in rooftop runoff, particles washed from asphalt shingle and galvanized metal roofs at two distances from a major expressway were analyzed for major and trace elements and PAHs. Concentrations and yields from rooftops were compared between locations and roofing material types to evaluate rooftop sources and their potential contribution to stream loading. Concentrations of zinc, lead, pyrene, and chrysene on a mass per mass basis exceeded established sediment quality guidelines for probable toxicity to benthic biota. Yields of all contaminants investigated were greater from sites nearer to the expressway, although some concentrations were lower. Yields of particle-bound zinc, cadmium, and nickel were significantly greater from metal roofs, and yields of lead were significantly greater from asphalt shingle roofs. RÉSUMÉ Dans les environnements urbains, les toits sont à la fois une source et un chemin pour le ruissellement contaminé. Pour mieux comprendre l'importance de la contamination associée aux particules dans le ruissellement des toits, nous avons analysé les particules provenant de deux sortes de toits, à deux distances d'une autoroute, en termes d' éléments majeurs, mineurs et de HAPs. Les concentrations de zinc, plomb, pyrène et chrysène, associés aux particules, ont excédé les recommandations établiees pour la toxicité probable à la faune benthique. Pour tous les contaminants la masse superficielle spécifique à été plus importante pour les toits plus proches de l'autoroute, même dans les cas où les concentrations ont été moins importantes. La masse superficielle spécifique de zinc, cadmium et nickel associés aux particules, étaient plus importante pour les toits en métal que pour les toits en asbestos shingle, tandis que pour le plomb c'était plutôt l'inverse.

Land cover controls on summer discharge and runoff solution chemistry of semi-arid urban catchments

“…Solutes clustering in R1 (Cd, Cu, Zn and V) are associated with rooftops, as well as industrial, commercial and road land uses (Chebbo and Gromaire, 2004;Davis et al, 2001;Gromaire et al, 2001;Pitt et al, 1995;Tiefenthaler et al, 2008;Van Metre and Mahler, 2003). We expected the highest concentrations of R1 solutes in catchments with high commercial land uses, road density and imperviousness.…”

Runoff Reduction Effects of Green Roofs in Vancouver, BC, Kelowna, BC, and Shanghai, P.R. China

“…By applying green roofs to buildings, the quantity of stormwater runoff can be reduced and the quality of runoff improved (Peck et al, 1999;Van Metre and Mahler, 2003). Research from Europe and North America has shown that green roofs can significantly reduce stormwater runoff volume and peak flow runoff by retaining rainwater in the growing medium (Köhler et al, 2001;Dunnett and Kingsbury, 2004;Liu, 2004;Moran et al, 2004;Bengtsson et al, 2005;Connelly, 2006).…”

Contamination of Detained Sediment in Sustainable Urban Drainage Systems

“…The average CF values for the monitored SuDS assets are presented in Table 8. Key urban contaminants illustrating enrichment relative to background soil concentrations within the monitored SuDS are Zn, Pb, Mn, Cu and Sn; primarily vehicle residuals (from engine wear, combustion, tyre and break material wear), urban road dust, urban waste and industrial emissions or processes [17,45,46]. High enrichment values of a contaminant may occur as a result of greater detainment of the contaminant within the specific SuDS asset, the enrichment of sediment by that contaminant due to a phyto-or chemical processes within the asset, or the lack or limited remediation of the contaminant by the specific SuDS asset.…”