Radiation report puts increase down to medical breakthroughs

The average amount of harmful ionising radiation Britons are exposed to has risen by almost 4% since 1999 according to a report released by the Health Protection Agency this week.

When ionising radiation passes through the body it has sufficient energy to damage DNA, leading to possible cell death and mutations that can contribute to cancer and genetic defects in offspring.

The report published by the agency’s radiation protection division shows the average annual dose is now 2.7 millisieverts (mSv) compared to 2.6 mSv six years ago when the last study was carried out.

While at 84.5% naturally occurring radiation accounts for the vast majority of exposure medical procedures account for a significant dose at 15% of the total.

The agency put this down to the increase in the use of new techniques such as computed tomography (CT) scans.

The remaining half per cent of the annual dose can be traced to products used, processes in the workplace, fallout and discharges of radioactive waste.

While the dose from waste from the nuclear industry has continued to fall for several years, the overall recorded exposure from discharges has increased since 1999.

The HPA says this is due to changes in the way the category is monitored, as for the first time naturally occurring radioactive substances discharged from the phosphate, oil and gas industries fell into this bracket.

Interestingly, although cosmic radiation at ground level has remained stable the average dose has increased slightly as the nation takes more flights.

Radon remains far and away the biggest source of ionizing radiation people are exposed to, accounting for half the annual total on average.

The actual exposure from radon varies wildly across the country, with individuals receiving as little as 0.3mSv to as much as 100mSv depending on their postcode.

Dr Roger Cox, director of the HPA’s Centre for Radiation, Chemical and Environmental Hazards, said: “Examining sources of radiation exposure is an important part of our work.

“We have assessed the doses people receive from all sources of ionizing radiation.

“There is a slight increase compared to earlier reports but this is not significant.
“What is more important are the large variations in exposures in different parts of the country due almost entirely to radon exposures.

“We welcome the measures being taken to reduce exposures in high radon areas.”

Environmental pressure group Greenpeace said the relatively high doses from radon should not be allowed to mask the exposure from artificial sources.

“We have never dismissed the exposure from radon and think a lot more work needs to be done in badly-affected areas,” said spokesperson for the environmental pressure group Jean McSorley.

“But the fact there are high levels of naturally occurring radiation does not justify the additional impact human activity is having,”
“The 0.1% from industry discharges is 0.1% we could do without.”

She said that while the HPA figures might be accurate across the country, the use of averages could be misleading as they did not highlight potential radiation hotspots.

She also questioned the use of some medical procedures, saying the treatment could on occasion be more damaging than the ailment.

“When they look at radiation exposure from industry or medical treatment the benefit has to outweigh the negative effects,” said Ms McSorley.

“There’s a big question mark around some medical exposures and whether they are always in the best interest of the patient.”

The report does not consider less harmful non-ionising radiation, such as that from mobile phone use and booster stations.

by Sam Bond

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