Disinfection By Products in Swimming Pool Water
- Lothar Erdinger
- Claudia Lehr
For hygienic reasons, disinfection of swimming pool water is indispensable. However, being a strongly oxidizing and halogenating compound chlorine will react readily with inorganic and organic components. Chlorate is probably the most important inorganic DBP and can reach high concentrations in pool water. Main organic Disinfection By Product (DBP) is chloroform, which is formed during reactions of chlorine with natural organics in the water, with human skin and organics released into the water by bathers. Next to chloroform (CCl3) mixed haloforms will be produced if bromide or iodide is present in the water. Concentration of DBPs in the water is mainly influenced by their production rate and their outtake into the air. Main route of exposure is by inhalation, whilst uptake through the skin contributes only about one third. Although chloroform is not degradable by UV radiation due to absorbing effects of nitrate in the water, bromoform is much better removable this way. A method has been developed and patented to chemically shift haloform production to the bromoform side and to remove this product by UV irradiation. However, pathways of haloform production in the water are mostly unknown. For sure, intermediate products will be formed containing chlorine bound in a-position to carboxylic groups. These compounds can cause stronger eye-irritating effects than hypochlorite. Our research targets on the identification of pathways of DBP formation in swimming pools and their evaluation.