Water Study Detects
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
Graphic credit: EPA
What is the EPA-USGS Study: Contaminants of
Emerging Concern in Treated & Untreated Drinking
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
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
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
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
([email protected]). 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.
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.”