Health Risk Evaluation of Disinfection By-Products (DBPs) for Indoor Swimming Pool Users via Life Cycle Impact Assessment Approach

Abstract

Due to continuous disinfection and constant organic load from swimmers, indoor swimming pools constitute environments with high levels of DBPs in water and air, some of which are linked to human health concerns. The purpose of this study is to customize current global-scale or continental scale life cycle human health impact assessment models to indoor swimming pool applications and subsequently use the model to compare different operation scenarios, which can provide relatively straight forward ideas for possible mitigation strategies. A comparison study is carried out between “baseline” scenario and four specific ‘what-if’ scenarios (using alternative disinfectant, reducing precursors, increasing ventilation, and changing characteristics of the air-water surface). We build the indoor-scale model based on USEtox, the consensus environmental model for characterisation of human and ecotoxicological impacts in Life Cycle Impact Assessment (LCIA). The model estimates the potential health risks for adults and children for 20 years during which age-specific intake factors change over time. The primary results indicated the impact from inhalation dominates the overall human health impact, while the dermal adsorption during swimming also makes significant contribution. The chloroform and trichloramine are identified as major stressors for inhalation human impact, while chloroform for dermal absorption impact. Through the scenario comparison, improving the ventilation of indoor swimming pools is an effect way to reduce the human health impact for all subjects. Another promising method is to control the precursors through increasing freshwater exchange, especially for the heavily-used pools. This study implies the choice of mitigation strategies should depend on the function and operation time of the pool. Through incorporating the proposed life cycle human health impact assessment model to the cradle-to-grave life cycle assessment studies, a systematic and comprehensive environmental profile of indoor swimming usage can be available.