Key Scottish Environment Statistics 2013

Activity Concentrations in Milk: 1966-2012³

Activity concentrations

Exposures to ionising radiation from radioactive substances can have an impact on human health. For this reason a number of foodstuffs are monitored each year to assess that the public has been adequately protected from ionising radiation.

Cows' milk is a widely consumed foodstuff that can provide a valuable indicator of changes over time. Samples are bulked from a number of farms to provide an extensive surveillance area. From 1966 until 1980, there were gradual falls in the concentrations of Caesium-137 (¹³⁷Cs) and Strontium-90 (⁹⁰Sr) until the concentration was so low it was difficult to detect. This reflects a decline in atmospheric radioactive fall-out, following the ban on above-ground nuclear weapons testing under the 1963 Partial Test Ban Treaty between the UK, USA and former USSR.

Following the Chernobyl reactor incident in 1986, concentrations of ¹³⁷Cs in milk peaked in 1987 and then began to fall again and are now below pre-Chernobyl levels.⁴ In 2012, the concentration of ¹³⁷Cs was <0.041 Bq/litre and ⁹⁰Sr was <0.055 Bq/gram of calcium. However, even at its peak the ¹³⁷Cs concentration in milk was still below the Community Food Intervention Levels, defined by Euratom Regulations EC/3954/87 and EC/2218/89, which were derived to ensure the protection of the public. At its peak concentration following the Chernobyl accident the levels of ¹³⁷Cs in milk were around 100 times lower than the intervention level.

Source: Scottish Environment Protection Agency / Metadata