Risk assessments of contaminated sites need to be more objective

– In the study we compared two different methods: the Swedish method for inventorying contaminated sites (MIFO) and the German method for individual assessment of contaminated sites (EB)," says Philipp Wanner, researcher at the University of Gothenburg and one of the authors of the study. 

The comparison shows that the Swedish method placed significantly fewer contaminated sites in the highest risk classes. When the German method was applied to the same areas, the proportion of contaminated areas in the highest risk classes increased by 39%. 

The researchers also found that almost half of the original Swedish assessment contained incorrect or incomplete information, and less than a third had a fully completed risk table.

The comparison study shows that the Swedish template documents are more text-intensive than the German ones. The researchers' assessment is that they are therefore more time-consuming to complete and more open to interpretation. The answers given also tend to vary depending on the level of expertise of the assessor. 

The German method, on the other hand, uses a spreadsheet with fewer fields requiring text. The classification is point-based and therefore less open to interpretation. The researchers argue that this method is more objective and advantageous compared to the current Swedish system.

- We recommend that the Swedish method also includes a quantitative method with a scoring or ranking system. This would increase the objectivity of the risk classification of contaminated sites.

A summary of the study's findings is published in 'European Science for Environment Policy' - a European Commission initiative to keep policy makers up to date with the latest results from environmental research. 

Read more about the study results in European Science for Environmental Policy, published on April 14, 2023.