Bob Kerr, 36, a Scottish scientist and mountaineer, set himself a unique challenge in May 2013. Not only would he attempt the ascent of Mount Everest, the world's highest peak, but while doing so he would measure cosmic radiation levels at over 29,000 feet above sea level. Bob reached a height of 26,000 feet on Everest before losing his vision and descending solo. The radiation detectors, however, reached the summit to complete this scientific study, thanks to the Nepalese guide Dorje Khatri, who died tragically in the recent avalanche. The study found that the time a climber spent on the mountain would deliver an extra 1milliSievert (mSv) of radiation dose. That's five times more than the average annual exposure of a worker in the UK nuclear power industry.
Bob, a chartered radiation protection professional based near Thurso, reported his findings on Wednesday 30 April 2014 to the Annual Conference of the Society for Radiological Protection (SRP) at Southport, Merseyside. Climbing Everest, the world's highest mountain, is difficult and dangerous enough in itself. The recent accident with 16 local guides killed or lost by an avalanche, brings the total death toll on expeditions to 265 from almost 7,000 summit attempt. So when every extra gram of weight counts in the thin air of the Himalayas, why complicate matters by carrying and using radiation measuring gear, however lightweight? "I'm often asked by fellow mountaineers about my job" says Bob.
"When chatting about my career in radiation protection I find that climbers, despite participating happily in one of the world's potentially hazardous hobbies, share the general public's emotional fear of radiation. "They don't realise that as they ascend into the heavens their exposure to natural background radiation from outer space (cosmic rays) increases. Safety and risk assessment is paramount on the mountains, just as it is when working with radiation. Why shouldn't they know if there is any significant extra risk from the cosmic radiation?" Statistical assessment of risk is a well established field of mathematics. Participants in extreme sports, while perhaps not aware of the numbers, usually take extra precautions to minimise the dangers. But accidents still happen. Rock climbers in the UK face a death risk of 1 in every 320,000 climbs. Add in all the extra hazards of high altitude ascents and, even before the latest fatalities, an Everest mountaineer's risk of death is 1 for every 28 people that reach the summit.
So just how cosmic radiation does a climber absorb on Everest? Is there a serious risk? "Not one fatality on Everest is due to cosmic radiation" says Bob "1mSv exposure however carries a small 1 in 10,000 risk of developing a fatal cancer some time in later life." Although summit attempts from the Nepalese side may be abandoned for this season out of respect for the victims, there are still mountaineers desperate to achieve a life-time ambition and stand on the top of the world. Bob hopes some time in the future to return to Everest to settle the small matter of the last 3,000 feet. But before then he faces the new challenge of a three-year stint as a member of the national council of the SRP. He will also be taking his finding international when he presents assessments of the radiation dose to the regular high altitude workers on the mountain to a meeting of the International Radiation Protection Association (IRPA) in Geneva.