Lab Matters Spring 2017 - Page 6

environmental health Nationwide Drinking Water Study Detects Contaminants of Emerging Concern Susan Glassmeyer, PhD, research chemist in the US Environmental Protection Agency's (EPA) National Exposure Research Laboratory recently sat down with Michaela Burns, writer for EPA's science communication team, to discuss a recent collaboration between EPA and the US Geological Survey (USGS). Graphic credit: EPA What is the EPA-USGS Study: Contaminants of Emerging Concern in Treated & Untreated Drinking Water? Contaminants of emerging concern (CECs) is a term that covers a wide variety of chemical and microbial contaminants that are not regulated but may end up in water. During the course of the day, many of the chemicals people use— from medicines to cleaning products—end up in their household wastewater, which is treated either on-site or at a municipal wastewater plant. Wastewater treatment is not always designed to remove these chemicals, so some persist through treatment and are released into surface or ground water. Another community downstream may use this water as their drinking water source. This study was designed to determine which chemicals and microorganisms persist through drinking water treatment. It was organized in two phases. In the first, nine drinking water treatment plants (DWTPs) were analyzed for 84 chemicals; in the second, 25 DWTPs were analyzed for 247 chemical and microbial CECs. Phase I was sampled in 2007, while Phase II was sampled from 2010-2012. A total of 77 analytes were analyzed in both phases of the study.  astewater treatment is not always designed to remove W these chemicals, so some persist through treatment and are released into surface or ground water. What methods did you use to measure contaminants of emerging concern and evaluate their potential effects on human health and the environment? All of the methods were research-based and most were state-of-the-art with extremely low detection limits. Liquid chromatography tandem mass spectrometry (LC/MS/MS) was often used for chemical analysis to achieve environmentally-relevant detection limits (in the range of 10 nanograms per liter for many chemicals). For the bacteria and viruses, quantitative polymerase chain reaction (qPCR) was used to amplify DNA present in the samples. An estrogen-responsive gene expression bioassay was used to monitor estrogenicity. 4 LAB MATTERS Spring 2017 What were the results of the study? In the larger, second phase of the study, we examined the water for 247 chemical and microbial analytes. Of those, 148 were detected at least once in the source water and 121 were detected at least once in the treated drinking water. Six analytes—copper, aluminum, strontium, lead, uranium, nitrate—occurred at concentrations in the source water which may cause health impacts to aquatic life. Two analytes—silicon and strontium—occurred in treated drinking water at concentrations that will require additional investigation to determine the potential for human health impacts. Two additional analytes—lithium and manganese—occurred at concentrations that will require further investigation because of new health studies that were not considered in the human health assessment. The estrogenicity bioassay measured estrogenic activity not captured by the analytical chemistry method but found levels still below estimated human and ecological effects levels. Are there opportunities for partnership between EPA and state/local public health and environmental laboratories? EPA’s Office of Research and Development is tasked with performing research to solve environmental problems. While we are not capable of acting as a contract laboratory and analyzing unlimited numbers of samples, we do have a Memorandum of Understanding (MOU) with APHL, which enables us to share research. State and local public health laboratories interested in learning more about the opportunities available under this MOU should contact Sarah Wright (sarah.wright@aphl.org). We are also willing to conduct webinars or other outreach activities to inform audiences about our research. What is the next step in research? One of the limitations of the study’s mass spectrometry methods is that it will only monitor the chemicals you specify. In future collaborations, we are including two additional types of techniques, non-targeted analysis and bioassays (like the estrogenicity bioassay), to determine the presence of other chemicals in water. Used together, targeted analyses, non-targeted analyses and bioassays may provide a richer picture of a water sample’s composition than any of the techniques independently. DIGITAL EXTRA: Read an overview of this study in Science of the Total Environment’s open-access article “Nationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States.” PublicHealthLabs @APHL APHL.org