On 25 October, NILU scientist Helene Lunder Halvorsen defended her doctoral thesis “Sources and processes controlling the occurrence of legacy POPs and organic contaminants of emerging concern in European air”.
Dr. Lunder Halvorsen is a scientist at NILU’s department of environmental chemistry and health effects, and has focused on Persistent Organic Pollutants (POPs) in her doctoral work.
POPs are chemicals that have harmful impact on human health and the environment. POPs are now regulated but were previously widely used in different applications as additives in products and as pesticides. Despite emission reductions, possible unintentional emissions may persist. Also, alternative chemicals have been introduced, which may have similar properties to POPs.
Lunder Halvorsen used European air samples from 2016 to investigate the occurrence, distribution and sources of POPs and the replacement chemical dechlorane plus. The emphasis was on Norway and the Arctic. The investigation was done by combining analysis data from a national and regional sampling campaign with data from source-receptor models.
The study showed higher concentrations of most POPs and dechlorane plus in densely populated regions in Europe, than in the more remote regions. The occurrence of POPs in remote regions supports their potential to travel far from their source of origin. Re-emissions from previously contaminated surface media were shown to affect the concentrations of most POPs across the region, while ongoing emissions were indicated for dechlorane plus and the byproduct PCB-11 (3,3’-dichlorobiphenyl). Hexachlorobenzene differed from the other POPs with higher concentrations at northern latitudes than southern-, and with higher concentrations compared to a similar campaign from 2006.
Helene Lunder Halvorsen’s doctorate was completed at the Department of Chemistry, University of Oslo. Her supervisors were Professor Knut Breivik, University of Oslo, Research Director Pernilla Bohlin-Nizzetto, NILU and Dr. Martin Schlabach (formerly NILU).