Quantification of continual anthropogenic pollutants released in swimming pools

• Laboratory pool tank experiments were done to determine sweat and pollutants released during swimming.
• On-site experiments were done to compare laboratory results with actual swimming pool results.
• The pool water temperature is the main parameter to control the sweat and pollutant release.
• The level of exercise is the second parameter to control the release.
• Unhygienic behaviour of bathers leads to the largest portion of the total pollutants released.

Disinfection in swimming pools is often performed by chlorination, However, anthropogenic pollutants from swimmers will react with chlorine and form disinfection by-products (DBPs). DBPs are unwanted from a health point of view, because some are irritating, while others might be carcinogenic. The reduction of anthropogenic pollutants will lead to a reduction in DBPs. This paper investigates the continual release of anthropogenic pollutants by means of controlled sweat experiments in a pool tank during laboratory time-series experiments (LTS experiments) and also during on-site experiments (OS experiments) in a swimming pool. The sweat released during the OS and LTS experiments was very similar. The sweat rate found was 0.1–0.2 L/m2/h at water temperatures below 29 °C and increased linearly with increasing water temperatures to 0.8 L/m2/h at 35 °C. The continual anthropogenic pollutant release (CAPR) not only consisted of sweat, particles (mainly skin fragments and hair) and micro-organisms, but also sebum (skin lipids) has to be considered. The release of most components can be explained by the composition of sweat. The average release during 30 min of exercise is 250 mg/bather non-purgeable organic carbon (NPOC), 77.3 mg/bather total nitrogen (TN), 37.1 mg/bather urea and 10.1 mg/bather ammonium. The release of NPOC cannot be explained by the composition of sweat and is most probably a result of sebum release. The average release of other components was 1.31 × 109 # particles/bather (2–50 μm), 5.2 μg/bather intracellular adenosine triphosphate (cATP) and 9.3 × 106 intact cell count/bather (iCC). The pool water temperature was the main parameter to restrain the CAPR. This study showed that a significant amount of the total anthropogenic pollutants release is due to unhygienic behaviour of bathers.

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