INTRODUCTION
The quality of the water and the air of swimming-pools is currently a topic of interest in occupational and environmental health. Even though the beneficial effects of swimming on increasing physical activity, cardiopulmonary fitness and improving lung function are undeniable1, concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming-pools.
The World Health Organization (WHO) highlights the need of adequate water disinfection of swimming-pools to prevent microbial proliferation. Disinfectants are the principal management-derived chemicals added to minimize the risk of microbial contaminants, and although several options are available (bromine, ozone, copper-silver, UV irradiation, electrochemically generated mixed oxidants, UV/hydrogen peroxide, etc) chlorine-based products have been typically preferred due to their effectiveness and lower overall relative cost, in spite of possibly leading to unwanted effects.
Indoor swimming-pools are of particular concern since they are used regularly all year round, and volatile chlorination by-products (CBPs) can become trapped within the swimming-pool complexes indoor air. The higher the concentration of these volatile CBPs in the water, the higher their concentration in the air above the pool2. Besides inhalation of volatile or aerosolized solutes, there are two other main routes of exposure to chemicals in swimming-pools: water ingestion, and skin absorption (which may represent a source of muco-cutaneous symptoms). These several routes add to the individual “exposome”, which comprises all environmental exposures that a person experiences from conception throughout the lifespan3.
CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated-pools as customers, particularly children, may also be affected has been a matter of debate. We aimed to review this topic, by describing the chemical and toxicity of these compounds given the types of exposure and reviewing health effects of such exposures in different populations considering also personal and environmental risk factors, in order to propose recommendations and to identify unmet needs in this area.