A survey of indoor radon in kanchanaburi province.

ABSTRACT

A study of indoor radon was carried out on 287 different buildings in four districts (Amphur Muang, A. Tha Muang, A. Tha Maka and A. Phanomthuan) of Kanchanaburi Province, Thailand, using an activated charcoal canister for sample collection and a gamma spectrometer for analysis of the samples. The survey revealed the presence of radon gas inside all the buildings investigated, with overall concentrations being 125.38 + 145.43 Bq.m-3 and the prevalence rate of elevated values being 31.70 percent. Concentrations of 131.14 + 116.36 Bq.m-3 with a 32.39 percent prevalence rate were obtained in Amphur Muang (71 buildings) ; 98.31 + 91.36 Bq.m-3 with a 22.41 percent prevalence rate in Amphur Tha Muang (58 buildings) ; 160.35 + 95.30 Bq.m-3 with a 56.66 percent prevalence rate in Amphur Tha Maka (60 buildings) ; 115.82 + 202.10 Bq.m-3 with a 21.24 percent prevalence rate in Amphur Phanomthuan (98 buildings). The higher prevalence at Amphur Tha Maka differs statistically from the prevalence encountered in the three other districts. In considering buildings constructed less than five years previously and those five or more years old, there were no statistically significant differences with regard to both the radon concentrations and the prevalence rate of elevated concentrations. There was evidence suggesting that sources of indoor radon are both the soil and construction materials. Buildings with good ventilation (e.g., houses built on high posts, and those with doors and windows frequently opened) showed somewhat less accumulation of indoor gas, without statistically significant difference (P>0.05).