Radon levels in three fish rearing buildings at Cleghorn Springs State Fish Hatchery, Rapid City, South Dakota, USA

Fish hatchery workers may be exposed to potentially health-threatening radon gas liberated from ground water used during fish rearing. This study surveyed the radon levels in three fish rearing buildings (small tankroom, tankroom, and rearing pavilion) at Cleghorn Springs State Fish Hatchery, Rapid City, South Dakota, USA. Overall radon values ranged from below the detection limit in all three buildings to a high of 2,317.68 Bq/m3 (62.64 pCi/L) in the tankroom. The pavilion had the lowest mean ± SE value of 56.57 ± 40.71 Bq/m3 (1.23 ± 0.11 pCi/L), while the highest mean value of 796.21 ± 54.61 Bq/m3 (23.67 ± 1.34 pCi/L) was in the small tankroom. Maximum radon levels were 1,231.36, 2,317.68, and 365.93 Bq/m3 (33.28, 62.64, and 9.89 pCi/L) in the small tankroom, tankroom, and pavilion, respectively. Radon levels were significantly correlated with the number of tanks receiving water in both the small tankroom and tankroom, but no such correlation was observed in the relatively open-air pavilion. Even though the water at the hatchery was aerated outside, additional aeration from rearing tank spray bars inside the enclosed small tankroom and tankroom resulted in relatively high radon levels.