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Occurrence of Contaminants of Emerging Concern During De Facto Reuse
Citation:
Glassmeyer, S. Occurrence of Contaminants of Emerging Concern During De Facto Reuse. To be Presented at Emerging Contaminants Short Course, Milwaukee, WI, October 22 - 23, 2019.
Impact/Purpose:
Samples were collected from upstream of a wastewater treatment plant (WWTP), the WWTP effluent, downstream , and at the intake of a drinking water treatment plant, along with the treated water. These samples were analyzed for 236 contaminants of emerging concern. The data showed some chemicals have a wastewater source, while others did not. The number of chemicals found in the treated drinking water was significantly lower than that in the wastewater effluent.
Description:
The drinking water and wastewater cycles are integrally linked. Chemicals that are present in commercial, industrial, and household wastewater may be sufficiently mobile and recalcitrant to pass through on-site or municipal wastewater treatment and survive natural environmental attenuation processes (e.g. sorption, degradation, etc.). Such persistent compounds have the potential to reach surface and ground waters that may be a source of drinking water. The US Environmental Protection Agency and US Geological Survey are collaborating on a series of projects to examine the sources, fates, and potential effects of contaminants of emerging concern (CECs) during de facto water reuse which occurs when treated wastewater is discharged to a source of drinking water. The first project involved applying the De Facto Reuse in our Nation's Consumable Supply (DRINCS) geospatial watershed model to source water data. This analysis determined that the concentrations of some classes of chemicals, such as pharmaceuticals, tended to be more closely related to the de facto reuse percentage of the source water, while others, such as per- and polyfluoroalkyl substances (PFAS), did not show a similar relation. The second project sought to directly investigate the persistence of chemicals downstream of wastewater treatment. The sampling design followed the surface flow path, with the collection of grab water samples from upstream of a wastewater treatment plant outfall and downstream to a drinking water treatment plant intake and through the plant to a finished water sample. The study used an integrated approach that includes a comprehensive analysis of over 200 specific organic chemicals (e.g. pharmaceuticals, PFAS); high resolution mass spectrometry to identify non-targeted (unknown) chemicals; in vitro bioassays (e.g. estrogenicity, androgenicity); rapid whole organism screens to assess cumulative bioactivity; and in vivo tests to address specific exposure and response endpoints. A rigorous quality assurance/quality control protocol was consistently applied from field to laboratory to ensure comparability of results from different techniques. This consistent, integrated approach combines the strength of each technique and builds upon the traditional CEC research approach by including environmental and toxicity endpoint assessments to more fully explore the potential effects to human health and the environment from chemical exposures. This presentation will provide an overview of both studies and results from the analysis for organic and inorganic chemicals from the samples collected during the second project.