Can green roof act as a sink for contaminants? A methodological study to evaluate runoff quality from green roofs
Highlights
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- This study investigated the potential of green roofs to act as sink for pollutants.
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- Experiments were conducted using pilot-scale green roof assemblies.
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- Different physico-chemical parameters were assessed for green roof runoff quality.
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- Portulaca grandiflora planted green roofs showed potential to act as a sink for pollutants.
Abstract
The present study examines whether green roofs act as a sink or source of contaminants based on various physico-chemical parameters (pH, conductivity and total dissolved solids) and metals (Na, K, Ca, Mg, Al, Fe, Cr, Cu, Ni, Zn, Cd and Pb). The performance of green roof substrate prepared using perlite, vermiculite, sand, crushed brick, and coco-peat, was compared with local garden soil based on improvement of runoff quality.Portulaca grandiflora was used as green roof vegetation. Four different green roof configurations, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). In general, the vegetated green roof assemblies generated better-quality runoff with less conductivity and total metal ion concentration compared to un-vegetated assemblies. Of the different green roof configurations examined, P. grandiflora planted on green roof substrate acted as sink for various metals and showed the potential to generate better runoff.
Graphical abstract
Keywords
- Green roofs;
- Water quality;
- Metals;
- Bioremediation;
- Biosorption;
- Runoff quality
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