RADON IN HOUSES OF CHIHUAHUA, CHIH. MEXICO. RISK FOR HEALTH

Radon-222 contributes 40% of the total effective dose to the population. This radioisotope depends of: geology of the area, the type of material used in built the houses, environmental and climatic conditions, and the particular characteristics of the house. Radon was measured in 86 houses in the city of Chihuahua, Chihuahua, Mexico. This city is surrounded by some uranium deposits, the best known is Peña Blanca, located 50 km north of the city. AlphaGuard PQ2000 Pro meter was used to measure the radon concentrations. Measure time was over 72 hours.

Was selected homes built with all types of materials: Brick (39 houses), adobe (13 houses), block (18 houses), concrete (4 houses) and other materials (12 houses).

After snuff, radon is the second leading cause of lung cancer. The EPA has set a limit of concentration indoors, called Intervention Level of 148 Bq/m³.

The aim of this study was to measure the radon-222 indoors concentration and calculate the annual effective dose to the population, during the time spent in the room.

The overall average of all households was 70.5 Bq/m³, range was 10-764 Bq/m³. By type of material: Brick, 85.4, adobe, 99.6, block, 36.7; concrete, 61.8 and other materials, 44.3, in Bq/m³.

The average annual effective dose for the whole city was 0.74 mSv. The 15% of the houses have average higher than the value recommended by the EPA. By type of material, we found that the annual effective dose was 0.89 for brick, 1.04 for adobe, 0.39 for the block, 0.65 for concrete and 0.47 for other materials, in mSv.

Higher values of radon concentration and high doses in the brick and adobe houses are a problem that must be attend, because there is a health risk. This values are due to surrounding uranium deposits.