Radioactivity in drinking water

The radioactivity of drinking water is monitored to assess the levels of man-made radiation exposure that humans are exposed to through drinking water.

The Cs-137 and Sr-90 concentrations in drinking water mainly originate from the Chernobyl fallout and the tritium (H-3) concentrations from nuclear weapon tests carried out in the atmosphere. The man-made radioactive materials analyzed from samples as part of the monitoring programme are usually present only in drinking water sourced from surface waters. A more significant radiation exposure in Finland is caused by naturally occurring radioactive materials in domestic water, the maximum concentrations of which in the water distributed by water utilities companies are restricted by Decree of the Ministry of Social Affairs and Health (1352/2015).

Drinking water samples are taken once a year, in spring or autumn, from the tap water in Helsinki, Oulu, Rovaniemi, Tampere and Turku.

The Sr-90 and Cs-137 concentrations in all samples were low in 2019. The H-3 levels in the samples were 1,0 Bq/l or below detection limit (less than 1,0 Bq/l) and thereby significantly below the maximum value of 100 Bq/l for H-3 under the Council Directive (98/83/EC) and Decree of the Ministry of Social Affairs and Health (1352/2015).

The variation in radionuclides between localities are due to both differences in the level of Chernobyl fallout in the region as well as the amounts of surface and ground water used as raw water. The raw water in Tampere consists of both surface and ground water. In Rovaniemi, only ground water is used, while in Helsinki and Oulu, drinking water is almost exclusively surface water. Since autumn 2012, the drinking water in Turku is sourced from artificial recharge.

The radioactivity levels of Cs-137, Sr-90 and H-3 in drinking water samples in 2019 (Bq/l).

Place Date Cs-137 (Bq/l) Sr-90 (Bq/l) H-3 (Bq/l)
Helsinki 3.5.2019 0,011 0,0045 1,0
Oulu 29.4.2019 0,0018 0,0026 <1,0
Rovaniemi 29.4.2019 <0,0002 <0,0001 <1,0
Tampere 17.5.2019 0,0018 0,0042 <1,0
Turku 30.4.2019 <0,0004 <0,0001 <1,0

 

The radioactivity levels of Cs-137, Sr-90 and H-3 in drinking water samples in 2018 (Bq/l).

Place Date Cs-137 (Bq/l) Sr-90 (Bq/l) H-3 (Bq/l)
Helsinki 3.10.2018 0,012 0,0045 <0,94
Oulu 1.10.2018 0,002 0,0030 <0,94
Rovaniemi 10.10.2018 <0,0002 0,0002 <0,94
Tampere 10.10.2018 0,003 0,0039 <0,94
Turku 2.10.2018 <0,0004 <0,0001 <0,94

Contact

Contact

  • Vaaramaa Kaisa
    Head of Laboratory / VAM tel. +358975988521