However, Stockholm Vatten, responsible for producing and delivery drinking water to a million people in and around the capital, believe the concentrations to be so small that there’s no reason for concern.
Someone would have to drink 5m litres of water in a day to get the equivalent of a daily dose of the tranquilizer Sobril.
Carina Wahlberg, an environmental chemist at Stockholm Vatten, commented:
“The results aren’t unexpected. We’re aware that it’s possible to detect traces of medicines in very low concentrations with the highly sensitive measuring instruments that we have today.”
The substances found come from Sobril; the blood pressure lowering drug, Seloken; the anti-inflammatory agent, Naprosyn; and the painkiller, Dextropropoxifen.
Stockhom Vatten say the problem occurs because some medicines are not particularly degradable. Instead of being completely absorbed by the body, they are secreted in the urine and faeces, thus ending up in the water supply. They support the use of environmentally friendly drugs to prevent it becoming a more serious problem in the future.
“It’s perfectly safe to continue drinking water from the tap in Stockholm,” reassured Wahlberg. “Considering the negligible quantities, we think the safety margins are more than enough.”
Meanwhile, in the town of Piteå on the Norrbotten coast, the council have demanded that something be done about quantities of arsenic in drinking water in the area.
They conducted a survey of ninety privately-owned wells in the region and found that a fifth of them had concentrations above the World Health Organisation’s recommended limit of 10 micrograms per litre. Some wells were found with concentrations of as much as 800 micrograms per litre.
Olle Selenius, a medical expert at the Swedish Geological Survey (SGU), explained the problem:
“Arsenic is found naturally in certain types of soil and rock. In Piteå, it’s released from the bed-rock into the water. This is a particular problem in Bangladesh, where it has led to an increase in various cancers, including skin cancer. A comprehensive survey is currently underway in many parts of the country including Piteå.”
At the moment, the known risk areas for arsenic in the water, apart from Piteå, are Västerbotten, Lappland and the area surrounding Mälaren.
Sources: Göteborgs Posten