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The origin of iodine detected in the air still unclear

The origin of iodine detected in the air still unclear

11 Nov 2016 16:00

Very small concentrations of radioactive iodine were still detected in air in Kotka at the end of October and the beginning of November. However, iodine has no longer been detected elsewhere in Finland. The most recent air collection samples are from Helsinki, taken 3–5 November and 5–7 November. Some of the samples collected at the beginning of November are still being analysed.

The samples collected in Kotka from 27 November to 6 October contained 0.6 microbecquerels of iodine per square metre. The quantity is very small and barely measureable and it does not affect human health or the environment.

Earlier in October iodine was also detected elsewhere in Finland. In addition, iodine was also detected at least in Estonia, Norway and Sweden.

The origin of the iodine is still unknown. As only iodine was detected in the air sample, it was apparently not emitted from a nuclear reactor, for instance. It is more likely that iodine was released from a plant manufacturing or processing iodine. Radioactive iodine is used in hospitals, for instance.

STUK monitors the concentrations of radioactive substances in outdoor air

The Finnish Radiation and Nuclear Safety Authority STUK monitors the levels of radioactive substances outdoors at eight localities in Finland. Air particles are collected with pumps in samplers to a fiberglass filter, and the filters are analyzed in a laboratory. The method can detect very small changes in radiation.

In addition, STUK monitors outdoor radiation in Finland with the help of an automated radiation monitoring network composed of 255 monitoring stations. The monitoring stations give an immediate warning if the radiation level rises above the level of normal background radiation, which is 0.05–0.3 microsieverts per hour. The normal variation that occurs in outdoor radiation is greater than that caused by the measured iodine levels. This is why the monitoring network does not detect the levels that have now been found in outdoor air in laboratory measurements.

Further information:

Director Tarja K. Ikäheimonen, tel. +358 9 759 88 596

Environmental radiation
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