The purpose of the study was to consider the environmental risks posed by the contamination of outlet water and sediments from stormwater ponds by both heavy metals and hydrocarbons. It also sought to relate the levels of contamination to characteristics of each pond’s catchment.
The results showed that concentrations in both outlet water and sediment sometimes exceeded guideline values, with zinc and lead being the most critical contaminants. No correlations were found between contaminant concentrations and catchment characteristics, including impervious area, pond area, pond age and traffic intensity. However, the sources of Zn, Cu and Pb appear to be similar as all concentrations were correlated. In addition, sediment color and texture were indicative of contamination, with loose black sediments found to be more contaminated than sticky, grey sediments, possibly due to differences in particle sources.
The study was carried out in collaboration with Laholmsbuktens VA, the utility company responsible for drinking water and sewer systems in Halmstad and Laholm, Sweden. It was supervised by Kelsey Flanagan and examined by Lian Lundy from the Urban Water Engineering group at Luleå University of Technology.