The health risk from radioactivity in food in Norway is low for most people. Individuals with high consumption of reindeer meat from highly contaminated areas, and those consuming drinking water from wells containing radon are most exposed.
This is the key message in the risk assessment on radioactivity in food, conducted by the Scientific Committee for Food Safety (VKM) on request from the National Food Safety Authority (NFSA).
The background for the request is NFSA’s review of the maximum levels for radioactive substances in drinking water, food and feed, and revision of procedures for reducing radioactivity in food.
All food products in the human diet contain radioactive elements. Although some of these elements are due to human activity, most radioactive elements present in our diet are of natural origin.
However, contamination from the Chernobyl disaster in 1986 is still present in some parts of Norway. Relatively high concentrations of caesium-137 may still be present in reindeer, sheep and mushrooms in the most contaminated districts.
Exposure to radioactive elements increase the risk of cancer. This is likely to occur also at the low doses present in food and beverages. The risk is dose-dependent.
The VKM has estimated the cancer risk at different exposure levels in food. The estimations are based on radiation risk estimates from international radiation protection agencies Estimating cancer risk associated with the low exposure levels from food, is highly uncertain. As defined in the report, the estimated risks have been categorised as extremely low, very low, low or moderat.
The assessment shows that the cancer risk from exposure to naturally occurring radioactive elements in food in Norway is low. The risk from exposure to anthropogenic radioactive elements in food is very low. This is valid for all age groups assessed.
For high consumers of the most contaminated reindeer meat, the excess cancer risks from caesium-137 varies from low to moderate, depending on the consumption level.
For high consumers of the most contaminated sheep meat, the excess cancer risk is low, whereas the risk for people with high consumptions of game, mushrooms and berries from areas contaminated after the Chernobyl disaster, is very low.
Seafood contains relatively high levels of the naturally occurring polonium-210 compared to other food groups. For high consumers of fish and shellfish, the risks from polonium-210 were low and very low, respectively.
Drinking water from groundwater supplies contain varying levels of radon-222. Some wells drilled in bedrock may contain especially high levels. The excess risk for consumers using this drinking water, is estimated as low to moderate depending on the radon-222 levels.
- More than 80 percent of the Norwegian population is supplied by surface water, which does not contain radon-222, says Jan Alexander, chair of VKM’s Scientific Steering Committee.
Ever since the Chernobyl accident, the Norwegian government has implemented various measures to reduce the amount of caesium-137 in food from contaminated areas. One important measure has been to feed reindeer and sheep non-contaminated food before slaughter, as caesium-137 is excreted quite quickly from the body as soon as the intake stops. The Government has also followed up on reindeer herders, who are high consumers of reindeer meat.
The assessment shows that without countermeasures, todays mean level of caesium-137 in reindeer meat could increase with five percent. For reindeer meat from the most contaminated animals, the increase in caesium-137 levels could be about 20 percent.
For sheep meat, today’s mean level of caesium-137 could have increased with 30 percent. For high consumers of the most contaminated sheep meat, the risk would increase by about seven times from low to moderate.
Jan Alexander emphasises that some of the scenarios are based on worst-case assumptions.
-The VKM notes that the risk estimates are indications of risks at the population level and should not be used to calculate any incidences of cancer.
It is likely that the actual risks are lower than those estimated, says Alexander.
In Norway, the maximum level for radioactive caesium in reindeer meat is 3,000 becquerel per kilo (Bq/kg). The VKM has estimated hypothetical health risks provided the maximum level was reduced to 1,500 or 600 Bq/kg. Today’s maximum level for other foods is 600 Bq/kg.
The calculations showed that reducing the maximum level to 1,500 Bq/kg would reduce the national mean level of caesium-137 in reindeer meat by about 5 percent. In the most contaminated animals, the caesium-137 level would be reduced by 30 percent.
If the maximum level were reduced to 600 Bq/kg, the mean level of radioactivity in reindeer meat would be reduced by 20 percent.
-A reduction of the maximum level from 3,000 Bq/kg to 600 Bq/kg would reduce the concentration in meat from the most contaminated animals by 70 percent, and the risk would be reduced from moderate to low for very high consumers of this reindeer meat, says Jan Alexander. However, he points out that indiviuals with a high consumption of reindeer meat from these districts already receive dietary advice to reduce exposure.
The EU has laid down maximum permitted levels on radioactive contamination of foodstuffs and feedstuffs following a nuclear accident. Norway has not established a set of maximum limits in the event of a nuclear emergency.
The VKM has assessed that EU’s maximum permitted levels for emergency situations when it comes to food would provide approximately the same level of protection in Norway as in the EU. These values are therefore considered appropriate for managing such situations in Norway. It is noted, however, that the EU’s maximum permitted levels for feed might result in meat contamination levels exceeding the maximum permitted levels in Norway.
The Scientific Steering Committee of the VKM is responsible for this risk assessment.