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Use of In Vitro Assays to Assess the Contribution of Environmental Contaminants on Water Mutagenicity
Citation:
DeMarini, D. Use of In Vitro Assays to Assess the Contribution of Environmental Contaminants on Water Mutagenicity. Effect-Related Evaluation of Anthropogenic Trace Substances: Concepts for Genotoxicity, Neurotoxicity, and Endocrine Effects, Aachen, GERMANY, October 22 - 23, 2015.
Impact/Purpose:
This conference is on water contaminants, which is an issue of high concern to the Office of Water. The work Dr. DeMarini proposes to present is unpublished research involving water contaminants and their potential health effects.
Description:
Although the formation and associated health effects of disinfection by-products (DBPs) in drinking water have been studied for nearly 40 years, similar research on swimming pool and hot tub (spa) water has begun only recently. Unique to pool and spa waters is the role of human inputs (skin, cosmetics, urine, hair, etc.) to the chemistry and resulting biological effects of the waters. In addition, the presence of pharmaceutical contaminants in source waters is increasingly becoming a concern. To address this cycle of DBP and mutagenicity formation, water samples were collected from public and private pools/spas from six sites in the U.S. where chlorine, bromine, or ozone-chlorine was used for disinfection. Additional samples were collected along the pathway from source to finished to tap to swimming pool/spa before/after intensive use. To evaluate the impact of pharmaceuticals on source waters, 5 different iodinated contrast dyes used for enhanced x-ray imaging were added to source water, which was then treated either by chlorination or chloramination. All of the waters were extracted by ethyl acetate/XAD and analyzed by a variety of analytical methods for DBP concentrations. The extract was concentrated 10,000 x in dimethyl sulfoxide for mutagenicity in Salmonella TA100 –S9. The results of the contrast-dye study showed that chloramination (not chlorination) of the source water containing either iopamidol, diatrizoate, or isohexol (but not iopromide) increased by twofold the mutagenicity of the source water. The results of the source-pathway study showed that there was a high correlation (r2 = 0.68 to 0.83) between the total concentration of the 9 haloacetic acids and the mutagenicity of the waters. Intense use of the swimming pool caused a doubling of the mutagenicity and the DBP concentrations of the water. The water sampled from a hot tub (spa) that had been cleaned 24 h earlier was generally twice as mutagenic as the tap water used to fill it. However, after 3 weeks of use, the spa water was nearly 10 times more mutagenic than the tap water (300 versus 3,000 revertants/liter-equivalent). This is the first demonstration of the impact of human inputs on the mutagenicity and DBP production in swimming pools and hot tubs (spas). Collectively, the results show the potential increase in DBP concentrations and mutagenicity due to pharmaceutical contaminants in source waters prior to disinfection, as well as the impact of human inputs on these outcomes when present in recreational waters such as swimming pools and hot tubs (spas). [Abstract does not necessarily reflect the policies of the U.S. EPA.]