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Progressive Increase in Disinfection By-products and Mutagenicity from Source to Tap to Swimming Pool and Spa Water: Impact of Human Use
Citation:
DeMarini, D. Progressive Increase in Disinfection By-products and Mutagenicity from Source to Tap to Swimming Pool and Spa Water: Impact of Human Use. 10th Congress of the Latin American Society of Mutagenesis, Teratogenesis, and Carcinogenesis, Montevideo, URUGUAY, October 13 - 16, 2016.
Impact/Purpose:
This is an abstract of a paper that is now in press in ES&T on the disinfection by-product concentrations and mutagenic potencies of a set of waters collected from 7 sites around the U.S., several of which form a series going from source, to finished, to tap, to swimming pool, to spa (hot tub). The results are of interest to the Office of Water and will provide information to them on the progressive increase in disinfection by-product concentration and mutagenicity along this series of water samples.
Description:
Pools and spas are enjoyed throughout the world for exercise and relaxation. However, there are no previous studies on mutagenicity of disinfected spa (hot tub) waters or comprehensive identification of disinfection byproducts (DBPs) formed in spas. Using 28 water samples from 7 sites, we report the first integrated mutagenicity and comprehensive analytical chemistry of spas treated with chlorine, bromine, or ozone, along with pools treated with these same disinfectants. Gas chromatography with high-resolution mass spectrometry and membrane-introduction mass spectrometry were used to comprehensively identify and quantify DBPs and other contaminants. Mutagenicity was assessed by the Salmonella mutagenicity assay. More than 100 DBPs were identified, including a new class of DBPs, bromoimidazoles. XAD/ethyl acetate extracts of brominated pool/spa waters were 1.8X more mutagenic than chlorinated ones; spa waters were 1.7X more mutagenic than pools. Pool and spa samples were 2.4 and 4.1X more mutagenic, respectively, than corresponding tap waters. The concentration of the sum of 21 DBPs measured quantitatively increased from finished to tap to pool to spa; and mutagenic potency increased from finished/tap to pools to spas. Mutagenic potencies of samples from a chlorinated site correlated best with brominated haloacetic acid concentrations (Br-HAAs) (r = 0.98) and nitrogen-containing DBPs (N-DBPs) (r = 0.97) and the least with Br-trihalomethanes (r = 0.29) and Br-N-DBPs (r = 0.04). The mutagenic potencies of samples from a brominated site correlated best (r = 0.82) with the concentrations of the 9 HAAs, Br-HAAs, and Br-DBPs. Human use increased significantly the DBP concentrations and mutagenic potencies for most pools and spas. These data provide evidence that human precursors can increase mutagenic potencies of pools and spas and that this increase is associated with increased DBP concentrations. [Abstract does not necessarily reflect the policy of the US EPA.]