Health risk as a consequence of exposure to trihalomethanes in swimming pool water

The article presents the formation and toxicity of trihalomethanes (THMs), substances belonging to Disinfection ByProducts (DBP), formed as a result of pool water chlorination. Concentration of THMs in pool water has been standardised in Poland since recently. THMs concentration in pool water depends on multiple factors, mostly the method of water disinfection, including chlorine or organic substance (TOC) concentration. Apart from that, the level of exposure of swimmers to the toxic effect of THMs is affected by their content in the air of swimming pool halls, intensity of swimming as well as time of stay in the indoor swimming pool area. The water and air temperature as well as number of swimmers and time of their staying in pool have also significance influence on THMs concentration. In order to decrease the quantity of THMs in pool water, alternative disinfection agents are applied. Additionally, an efficiently operating pool ventilation system as well as proper water treatment method are also important. Because THMs are produced from organic material under the influence of the chlorination, the users can have an impact on decrease of the THMs concentration in pool water, for instance by taking a shower prior to entering the pool or by wearing a swim cap. The results of studies conducted in 2015 showed that the quantity of THMs in pool water depends on type of the pool (indoor, outdoor), water replacement frequency, water treatment system, chlorine dose and TOC content. In most collected samples, the THMs concentration exceeded the admissible norm (100 μg/L).