Individual Monitoring Conducted by the Health Protection Agency in the London Polonium-210 Incident

摘要

Mr. Alexander Litvinenko died on 23 November 2006, having allegedly been poisoned with polonium-210 (~(210)Po) a few weeks earlier. The police investigation identified a number of contaminated locations, includingparts of several hotels, restaurants, offices and transport. An extensive programme of individual monitoring ofpotentially exposed persons was rapidly initiated, based on urine sampling. Methods used for low-levelmeasurement of ~(210)Po in environmental samples were adapted. The Health Protection Agency set a ReportingLevel of 30 mBq d~(–1), results above which indicated likely intake of ~(210)Po from the incident. At each location, riskassessments were undertaken to identify persons with significant risk of contamination with ~(210)Po. Theseindividuals were invited to provide samples, not only to enable a direct assessment to be made of their ownexposures, but also to inform decisions on whether others connected with the location should provide samples, orwhether they could be reassured. Urine samples from 753 people were processed: about 500 during the firstmonth. Of these, 139 measurements were above the Reporting Level, assessed doses for 36 were in the range ≥ 1mSv and <6 mSv, and 17 were ≥ 6 mSv, with the highest at about 100 mSv. Many of the hotel guests wereoverseas visitors. An Overseas Advice Team was set up to encourage authorities abroad to adopt similar strategies.Overall, 664 persons from 52 countries and territories were identified. For 176, results of urine measurementswere provided to the Overseas Advice Team, of which 13 were above the Reporting Level. Assessed doses foreight of these were <1 mSv, and the other five were in the range ≥ 1 mSv and <6 mSv.