Article Text
Abstract
Trichloramine is a disinfection by-product formed when chlorine reacts with nitrogen-containing contaminants in the pool water. Trichloramine can then evaporate from water to indoor air. Exposure to trichloramine can cause irritation in the airways, eyes, nose and throat of workers and swimmers. There is yet no Occupational Exposure Limit for trichloramine in Sweden.
Air levels of trichloramine were measured in altogether 41 indoor swimming pools located in different parts of Sweden. All swimming pools used sodium hypochlorite for water disinfection. The majority of the swimming pools (N = 30) were traditional public swimming pools with a 25 m pool and often also an instruction pool for children. Measurements were also performed in 7 adventure swimming pools and 12 rehabilitation pools.
Stationary air sampling was carried out next to the pool at about 1.3 m above the floor. Air was pumped (1 L/min) through a filter impregnated with sodium carbonate and arsenic trioxide, and the filters were analysed using ion chromatography. The sampling time was usually 2–3 hours, but varied from 1 up to 8 hours. The number of samples per swimming pool as well as the number of sampling days varied (from 1 up to 6 days), however in most of the pools sampling was performed on at least two different days. In total, about 400 air samples of trichloramine were collected.
For the traditional public swimming pools, the geometric mean (GM) concentration of trichloramine was 0.13 mg/m3. In the swimming pool with the highest levels GM was 0.29 mg/m3, and in the pool with the lowest levels GM was 0.02 mg/m3. In the adventure swimming pools air levels of trichloramine were generally higher, GM 0.20 mg/m3, with a highest individual GM of 0.40 mg/m3. For the rehabilitation pools, the levels were considerably lower, with a GM of 0.03 mg/m3.