Exploring the relationship between social deprivation and domestic radon levels in the East Midlands, UK.

The natural radioactive gas radon is widely present in the built environment and at high concentrations is associated with enhanced risk of lung-cancer. This risk is significantly enhanced for habitual smokers. Although populations with higher degrees of social deprivation are frequently exposed to higher levels of many health-impacting pollutants, a recent study suggests that social deprivation in the UK is associated with lower radon concentrations. The analysis reported here, based on published data on social deprivation and domestic radon in urban and rural settings in the English East Midlands, identifies a weak association between increasing deprivation and lower radon areas. This is attributed to the evolution of the major urban centres on low-permeability, clay-rich alluvial soils of low radon potential. In addition, the predominance of high-rise dwellings in towns and cities will further reduce average exposure to radon in populations in those areas.

Radium dial watches, a potentially hazardous legacy?

This study re-examines the risk to health from radium ((226)Ra) dial watches. Ambient dose equivalent rates have been measured for fifteen pocket watches giving results of up to 30 µSv h(-1) at a distance of 2 cm taken with a series 1000 mini-rad from the front face (arithmetic mean ambient dose equivalent for pocket watches being 13.2 µSv h(-1)). A pocket compass gave rise to a similar ambient dose equivalent rate, of 20 µSv h(-1), to the pocket watches, with its cover open. Eighteen wristwatches have also been assessed, but their dose rates are generally much lower (the arithmetic mean being 3.0 µSv h(-1)), although the highest ambient dose equivalent rate noted was 20 µSv h(-1). A phantom experiment using a TLD suggested an effective dose equivalent of 2.2 mSv/y from a 1 µCi (37 kBq) radium dial worn for 16 h/day throughout the year (dose rate 0.375 µSv h(-1)). For this condition we estimated maximum skin dose for our pocket watches as 16 mSv per year, with effective doses of 5.1 mSv and 1.169 mSv when worn in vest and trouser pockets respectively. This assumes exposure from the back of the watch which is generally around 60-67% of that from the front. The maximum skin dose from a wristwatch was 14 mSv, with 4.2 mSv effective dose in vest pocket. Radium ((226)Ra) decays to the radioactive gas radon ((222)Rn), and atmospheric radon concentration measurements taken around a pocket watch in a small sealed glass sphere recorded 18,728 B qm(-3). All watches were placed in a room with a RAD7 real-time radon detector. Radon concentration average was 259±9 Bq m(-3) over 16 h, compared to background average over 24h of 1.02 Bq m(-3). Over 6 weeks highs of the order of 2000 Bq m(-3) were routinely recorded when the heating/ventilation system in the room was operating at reduced rates, peaking at over 3000 Bq m(-3) on several occasions. Estimates of the activity of (226)Ra in the watches ranged from 0.063 to 1.063 µCi (2.31 to 39.31 kBq) for pocket watches and from 0.013 to 0.875 µCi (0.46 to 32.38 kBq) for wrist watches. The risk from old watches containing radium appears to have been largely forgotten today. This paper indicates a health risk, particular to collectors, but with knowledge and appropriate precautions the potential risks can be reduced.

The effects of geology and the impact of seasonal correction factors on indoor radon levels: a case study approach.

Geology has been highlighted by a number of authors as a key factor in high indoor radon levels. In the light of this, this study examines the application of seasonal correction factors to indoor radon concentrations in the UK. This practice is based on an extensive database gathered by the National Radiological Protection Board over the years (small-scale surveys began in 1976 and continued with a larger scale survey in 1988) and reflects well known seasonal variations observed in indoor radon levels. However, due to the complexity of underlying geology (the UK arguably has the world's most complex solid and surficial geology over the shortest distances) and considerable variations in permeability of underlying materials it is clear that there are a significant number of occurrences where the application of a seasonal correction factor may give rise to over-estimated or under-estimated radon levels. Therefore, the practice of applying a seasonal correction should be one that is undertaken with caution, or not at all. This work is based on case studies taken from the Northamptonshire region and comparisons made to other permeable geologies in the UK.

A critical comparison of the cost-effectiveness of domestic radon remediation programmes in three counties of England.

Radon remediation programmes in domestic dwellings were carried out in five areas, from three counties of England, and the total costs obtained. A single company, which abided by the Code of Practice of the Radon Council of Great Britain, carried out the remediation. The dose savings from the programmes were calculated and used to estimate the number of lung cancers averted. The data obtained allowed the cost-effectiveness of the remediation programmes in each area to be calculated. The remediation programmes in three areas (Northants 2, 3 and North Oxfordshire) were cost-effective whereas those in two areas (Northants 1 and North Somerset) were not. To be cost-effective, the Northants I and North Somerset areas would need to increase the number of householders that carried out remediation, if they were over the UK Action Level. Health policy makers should concentrate their resources on communities in areas where there is a significant proportion of dwellings above the UK Action Level and where the number of properties being remediated is low.