Cyanuric Acid Levels and Related Factors in Swimming Pools in a District of Beijing

Objectives To determine the level of cyanuric acid in swimming pools and related factors in the water quality of swimming pools in a certain area, and to provide scientific data for the development of relevant sanitary standards.

Methods From April to August in 2018, swimming pools using chlorinated isocyanurate disinfectants were selected to collect pool water, and analyzed six indicators including pool water temperature, turbidity, urea, pH value, free residual chlorine and cyanuric acid. Relevant basic information were collected and the cyanuric acid content and related factors in swimming pool water quality were analyzed by partial correlation test.

Results The median cyanuric acid was 23.0 mg/L, and the qualifed rate was 70.6%. Different swimming places, different structure design, forced shower, and different disinfectant dosing method had an effect on the qualified rate of cyanuric acid. The school pool had the highest qualified rate of cyanuric acid, followed by hotels and restaurants, and the lowest was social for-profit swimming pools. For the open-air swimming pool cyanuric acid, the pass rate was the highest, and the qualified rate of cyanuric acid in the indoor window swimming pool was higher than the cyanuric acid qualified rate in the indoor windowless swimming pool, and the qualified rate of cyanuric acid in the swimming pool with forced shower and automatic machine dosing was higher than that of the compulsory uric acid in the artificial dosing pool. The qualified rate was statistically significant (P < 0.05). Pool temperature and urea were positively correlated with cyanuric acid content.

Conclusions The qualified rate of cyanuric acid in the swimming pool of a certain area was not high. The temperature of the swimming pool and the content of urea and cyanuric acid were positively correlated. It is recommended that the manager choose the type of disinfectant reasonably. The cyanuric acid content in the swimming pool should be continuously paid attention to, and the swimming pool water should be replaced in time to protect the swimmers' health.