title: Metal and nutrient dynamics on an aged intensive green roof.
abstract: Runoff and rainfall quality was compared between an aged intensive green roof and an adjacent conventional roof surface. Nutrient concentrations in the runoff were generally below Environmental Quality Standard (EQS) values and the green roof exhibited NO3(-) retention. Cu, Pb and Zn concentrations were in excess of EQS values for the protection of surface water. Green roof runoff was also significantly higher in Fe and Pb than on the bare roof and in rainfall. Input-output fluxes revealed the green roof to be a potential source of Pb. High concentrations of Pb within the green roof soil and bare roof dusts provide a potential source of Pb in runoff. The origin of the Pb is likely from historic urban atmospheric deposition. Aged green roofs may therefore act as a source of legacy metal pollution. This needs to be considered when constructing green roofs with the aim of improving pollution remediation.
authors.affiliation: Geography, School of Environment and Development, The University of Manchester, Arthur Lewis Building, Oxford Road, Manchester M13 9PL, UK. Electronic address: andrew.speak@postgrad.manchester.ac.uk.
authors.forename: A F
authors.initials: AF
authors.lastname: Speak
authors.forename: J J
authors.initials: JJ
authors.lastname: Rothwell
authors.forename: S J
authors.initials: SJ
authors.lastname: Lindley
authors.forename: C L
authors.initials: CL
authors.lastname: Smith
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D003247:Conservation of Natural Resources; D004391:Dust; D004784:Environmental Monitoring / Q000379:methods*; D006798:Housing; D006801:Humans; D008670:Metals / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D004391:Dust; D008670:Metals
keywords: Green roofs; Lead; Urban runoff; Water pollution