On the university campus in Luleå, a number of miniature houses have raised curiosity and speculations about beehives or dog houses. Alexandra Andersson Wikström, PhD-student in Urban Water Engineering at Luleå University of Technology, is working on the project where a number of building materials are being tested to gain knowledge on which may contribute with pollutants from the urban environment to stormwater.
Results from a previous laboratory study showed that many commonly used roofing materials are potential contributors of metals and organic compounds to stormwater. For example, bitumen shingle showed potential to release metals and the organic compounds nonylphenols to stormwater, while a PVC sheet showed potential to release the organic compounds nonylphenols as well as phthalates. These results were part of the basis of selecting the building materials that are now to be studied in the outdoor environment – in reality.
"With this knowledge we can prevent some of these pollutants ending up in stormwater, by, for example, avoiding using the materials that are the cause. The information could for example be used by municipalities to make estimates of the concentrations that could be expected in the stormwater from given areas, but also in environmental certification programs for buildings and neighbourhoods", says Alexandra Andersson Wikström.
The building materials on the miniature houses that are now built and standing outdoors will be exposed to natural weathering and wearing, in order to be able to investigate how time and material age will affect the release of pollutants. Other factors that can affect the release of pollutants from the materials, for example the outside air temperature and rain intensity, will also be studied.
"In cases where the release of pollutants to stormwater cannot be prevented, stormwater may instead need to be treated. More knowledge is needed to be able to develop treatment facilities that are suitable to deal with the targeted groups of pollutants", says Alexandra Andersson Wikström.
The materials being tested are: PVC sheets, bitumen shingle, bitumen felt roof, copper sheet, zinc sheet, galvanised steel, corten steel (weathering steel), stainless steel and coated, corrugated steel. This project is a continuation of another project with laboratory tests in the same field that we wrote about last year, see the link below: