En man i ett laboratorium.
Photo: Malin Arnesson

Our groundwater is threatened by many different contaminants


Access to clean water is something we often take for granted in Sweden. But our groundwater is being threatened by different types of contaminants. In Sweden alone, 82,000 contaminated sites have been identified. Philipp Wanner is a hydrogeologist, who investigates how contaminants infiltrate groundwater.

OUR GROUNDWATER IS  an invaluable natural resource, comprising 99% of all available fresh water. This is because most of the Earth’s fresh water is stored in polar ice and glaciers, and is therefore not available to us. But there are also major threats to groundwater caused by contaminants that seep down through the soil and adversely affect groundwater. Some contaminants come from a specific source – some form of activity that has taken place on the site – but there is also diffuse dispersion from agricultural activities or through the air. And since many contaminants remain in the ground for decades, or even centuries, many of the contaminants in our soil today come from activities that were closed down long ago. 

PHILIPP WANNER HAS BEEN an associate senior lecturer at the University of Gothenburg for a number of years. Born and raised in Switzerland, he became interested in hydrogeology early in his studies. He studied geology at the University of Bern, and in his Master’s thesis he investigated the impact of mining on the groundwater in Oman. Since then, he has continued in the same field, and in the midst of the pandemic, he and his family moved to Gothenburg.
   “I was looking for a position that would take me further in my career and found this job. Scandinavia seemed like a good place to bring my family to, and we are all very happy here,” says Philipp Wanner.

AS A HYDROGEOLOGIST specialising in contaminants, he studies dispersion patterns to predict how contaminants will affect groundwater and what measures need to be taken. Contaminants can be of different types. In one of his research projects which is funded by the Swedish Research Council, Philipp Wanner is investigating how plastic particles affect the dispersion of pesticides from agriculture.
  “When plastic particles and pesticides coexist in agricultural land, we can expect an interaction between the plastic and the pesticides. This could potentially increase the transport of pesticides into the groundwater systems,” he says. 

En hand håller i provburkar.
Philipp Wanner investigates how plastic particles can affect the spread of pesticides from agriculture.
Photo: Malin Arnesson

Other contaminants that Philipp Wanner is studying are per- and polyfluoroalkyl substances (PFAS). PFAS is an umbrella term for over 10,000 different substances, all of which are difficult to break down and some of which can have harmful effects on both humans and the environment. All PFAS are synthetically produced and do not occur naturally in the environment. Many repel dirt and grease and are used, for example, in functional apparel, detergents and cosmetics. Others are used in firefighting foam for their ability to rapidly form a film between the foam and the burning liquid. In a project funded by Formas, he is investigating how PFAS behave when we artificially infiltrate surface water into the groundwater. This is often done in Sweden to ensure sufficient groundwater for our drinking water supply.
   “Surface water usually has a high concentration of PFAS, so it is important to investigate what happens when you take surface water and infiltrate it into groundwater,” says Philipp Wanner.

CLEAN DRINKING WATER is taken for granted in Sweden, and not everyone is aware that our groundwater can actually be contaminated. For example, there are 800,000 private wells in Sweden and in these wells there is no regular monitoring of water quality. Philipp Wanner often points this out to his students.
    “If you have your own well, check the water at least twice a year! You never know what might have affected the water quality, so don’t rely on old results,” he says.

He himself lives in a house with access to its own well. When the vendor was asked if the water quality had been checked, the answer was yes – 12 years ago.

PROVIDING CLEAN DRINKING WATER in the future is one of the great challenges of our time. And although the public may not be very familiar with the problem, Philipp Wanner still feels that there is interest in the community in doing something about it. For example, the EU has lowered the limit value for the PFAS content in drinking water, with the result that Sweden is lowering its threshold value from 90 nanograms per litre to 4 ng/l from 2026. However, there is much left to be done. 
    “There is a risk that our drinking water will become increasingly contaminated, and if we don’t solve the problem, it will have a major impact on human health.” 

Text: Camilla Persson
Photo: Malin Arnesson

Philip Wanner
Philip Wanner
Photo: Malin Arnesson

Philipp Wanner

Age: 36 år.

Originally from: Switzerland

Family: Wife and three children aged 2, 5 and 7

In his spare time: Being with his family and playing floorball.

Contaminated groundwater

THEN: In the 1970s, chlorinated solvents were used widely, including in the engineering industry. 20,000 tonnes a year were used in Sweden alone. The substances were found to have a negative impact on the environment, and since then some solvents have been completely phased out through restrictions and bans.

NOW: An inventory of existing contaminants
is continuing, and researchers are investigating how they get dispersed in the ground. There is a lot of talk today about PFAS, as PFAS are present everywhere in the environment, including in groundwater, and have negative effects on human health even at low concentrations. It is also currently unclear how all PFAS-contaminated sites can be decontaminated.

IN THE FUTURE: It is hoped
that in the future we will have such good knowledge about which substances adversely affect the environment that we will have replaced hazardous substances with substances that do not affect our groundwater. It is also hoped that we will find new ways of decontaminating contaminated sites and cleaning the groundwater.