El. Fisher et al., OCCUPATIONAL EXPOSURE OF WATER-PLANT OPERATORS TO HIGH-CONCENTRATIONSOF RN-222 GAS, Journal of occupational and environmental medicine, 38(8), 1996, pp. 759-764
Water-plant operators may be exposed to high airborne radon-222 (Rn-22
2) concentrations created when Rn-222 gas transfers from water to air
during the water treatment processes. To evaluate this hazard, we plac
ed yearlong alpha-track radon detectors in 31 water plants. The geomet
ric mean of the annual average airborne Rn-222 concentrations was 3.4
pCi L(-1) (126 Bq m(-3)), with a maximum of 133 pCi L(-1) (4921 Bq m(-
3)). We assessed the short-term temporal variability of Rn-222 by moni
toring four water plants continuously for a 3- to 6-day period. Cumula
tive working level months were estimated for the time workers were in
the water plants. Because airborne Rn-222 concentrations in water plan
ts can reach levels considered unsafe for underground miners, it would
be prudent to monitor airborne Rn-222 concentrations in water plants
which aerate water as part of their treatment process.