In analysing animal and environmental samples in and around Oslo, researchers discovered a range of substances that break down very slowly. Chemist Eldbjørg Sofie Heimstad says the long-term effects of being exposed to some of them are poorly understood.

Researchers warn of toxins accumulating in the environment

When researchers took samples of animals and the environment in Norway's capital, they uncovered substances that were phased out of production in the 1980s, as well as substances still in use today. 

"PCBs were banned in 1980, but we're still finding them. It's disconcerting that they remain so stable in the environment that we can still detect them even though they haven't been used or produced for a long time," says Eldbjørg Sofie Heimstad, chemist and research director at the Norwegian Institute for Air Research (NILU).

Every year since 2013, researchers from NILU, the Norwegian Institute for Nature Research (NINA), and the Norwegian Institute for Water Research (NIVA) have analysed animal and environmental samples in and around Norway's capital Oslo. Their samples have included soil, fieldfare (snowbird) eggs, urban rat livers, and earthworms.

Overall, the researchers found a hundred different environmental toxins in the samples.

Among the substances the researchers are most concerned about are those in the PFAS category. The researchers have summarised the insights provided by their analyses of these substances in a research article published this year.

The report on the 2022 results was also recently published.

Many substances break down slowly

Some PFAS compounds have been banned, while others are still used for various purposes, such as in frying pans, ski wax, food packaging, and firefighting foam.

PFAS are also found in plastic food packaging, as reported earlier by

Like PCBs, PFAS compounds break down slowly, meaning they remain in the environment for a long time even after they are discontinued. According to Heimstad, our knowledge about what kind of long-term effects even low amounts have on humans and the environment is limited.

“Their stability increases the potential for them to pose an environmental risk," she says.

In earthworms, the concentration of the PFAS variant PFOS was higher than what Europe considers the tolerance limit in the diets of birds and predators.

Environmental chemist Dorte Herzke says it has been proven that variants of PFAS are carcinogenic and can affect the immune system.

May be carcinogenic

Dorte Herzke is an environmental chemist at NILU and the Norwegian Institute of Public Health.

She points out that when substances enter the environment, people are also exposed to them.

“One of the purposes of the study was to understand what people in a big city might be exposed to. We ingest the same substances as animals through air and drinking water,” she says.

Herzke says that some PFAS variants have been shown to have negative effects on our health.

“We know that they’re carcinogenic and can affect the immune system,” says Herzke.

She also points out that there is much we do not know, especially about newer PFAS variants.

“PFAS are just one of many types of substances we’re exposed to. How they all interact is something we haven't quite figured out yet,” she says.

Uncertain origin

Herzke says it is often not easy to know exactly where PFAS emissions come from.

“What we’ve learned in the past eight years is that we have a combination of specific PFAS point sources, and then places where we find PFAS simply due to so many people and their activities in a big city,” she says.

Point sources include airports and waste disposal sites, which are known to contribute to particularly high concentrations of PFAS. Parks in densely populated areas are an example of where PFAS are found without being linked to specific sources.

Could be banned

The EU is considering a proposal to significantly limit the use of PFAS.

On their website, the Norwegian Environment Agency writes that the proposal involves a total ban on the sale, import, and use of PFAS. The proposed exceptions are for certain specific uses, such as protective equipment for firefighters and certain types of refrigerants.

The proposal does not contain a list of specific PFAS variants. Instead, PFAS is defined by its structural composition, and the restrictions apply to all substances with that structure.

Toxins in dust

Researchers also found other substances in the environment that they believe could be cause for concern.

In their latest report, researchers analysed house dust, and in an article in the Norwegian newspaper Dagsavisen, NILU researcher Maja Nipen states that too little is known about the health risks of such dust.

That's why she recommended vacuuming often.

“Several of our studies suggest that we can ingest some environmental toxins through dust in amounts that may be higher than what the authorities have indicated as ‘safe levels’," Nipen said.

Some of the contaminants that researchers found in house dust include siloxanes, organophosphorus flame retardants, brominated flame retardants, and chlorinated paraffins.


Translated by Ingrid P. Nuse

Read the Norwegian version of this article on

Powered by Labrador CMS