The Influence of Contamination from Concrete Materials on the Growth and Accumulation of Metals within an Invasive Weed (Salix spp.)

Urban riparian vegetation is frequently dominated by invasive weeds, whose growth is often attributed to the elevated nitrogen and phosphorous in urban waters and soils. However, less recognition is given to other urban contaminants that may influence riparian vegetation. Previous studies have indicated that the dissolution of concrete modifies water and soil geochemistry and potentially enhances the growth of invasive species. This study investigated the relationship between urban water quality and the growth of an invasive urban riparian weed, willow (Salix spp.), to examine the contribution and influence of concrete materials. The study used water from endangered upland peat wetlands within and adjoining the Greater Blue Mountains World Heritage Area, many of which are in urban catchments and suffer degradation from water pollution and invasive weeds. In this study, willow cuttings were grown in a laboratory using four water treatments: pristine (non-urban), urban, and non-urban water exposed to two different concrete materials. The urban and concrete-exposed water treatments were associated with increased plant growth measures in addition to increased concentrations of barium and strontium that bioaccumulated in plant tissue.