Unsafe Manganese Levels Found in Massachusetts Drinking Water
By BOSTON UNIVERSITY SCHOOL OF
PUBLIC HEALTH
Now, a new study led by researchers at Boston
University School of Public Health (BUSPH) has found that concentrations of
manganese in a Massachusetts community’s drinking water often surpassed the
maximum recommended levels of manganese stated in current guidelines.
Published in the Journal of Exposure Science & Environmental Epidemiology,
a Nature publication, the findings also suggest that
the observed manganese levels may be high enough to pose a risk to children and
other vulnerable communities who are exposed.
Manganese is a naturally occurring component
of soil and rock, and it is both an essential nutrient and a toxic
substance—so, too little or too much exposure can be harmful to health. Despite
the fact that manganese is found in many communities’ drinking water across the
US, it is not federally regulated.
The US Environmental Protection Agency has
developed guidelines that identify a maximum level of daily exposure to
manganese for “aesthetic” purposes (i.e. color and taste), as well as for the
overall health and safety of the general population. But these guidelines are
only recommendations; they cannot be enforced in the way that established
primary standards can.
“Some level of manganese is needed for
health, but growing evidence suggests that excess levels of manganese can harm
children’s brains,” says study lead and corresponding author Alexa Friedman, a
doctoral student at BUSPH at the time of the study.
“Our findings suggest that the level of
manganese that is present in public drinking water exceeded, on average, the
aesthetic guidelines 40 percent of the time, and health-based guidelines 9
percent of the time. These data support the need for a legally
enforceable primary drinking water standard for manganese in order to
better protect children’s health.”
EDITOR'S NOTE: Iron and manganese are common in Charlestown's well water, sometimes causing discoloration and staining if not filtered. CLICK HERE for a URI fact sheet on the problem. - Will Collette
The new study is among the first to examine manganese concentrations in drinking water across time and location in the United States.
For the study, Friedman and colleagues
examined residential tap water samples collected between September 2018 to December
2019 in the suburban community of Holliston, Mass., as part of a
community-initiated pilot study called ACHIEVE (Assessing Children’s
Environmental Exposures).
Holliston residents had reported concerns about the quality of their drinking water and the safety of children in the community after noticing that their tap water turned black or brown occasionally.
Communities that receive tap water from shallow aquifers are
especially vulnerable to being exposed to high levels of manganese, and
Holliston residents rely on this source for almost all of their drinking water.
“Although average water
manganese concentrations in Holliston were relatively low, our work showed that
levels nonetheless often exceed the current aesthetic and health-based
guidelines,” says study senior author Birgit Claus Henn, associate professor of
environmental health at BUSPH.
“While the existing guidelines may be helpful
benchmarks, without an enforceable standard in place, there is a limit to what
will be done to ensure the water is safe to drink and/or meets these
guidelines.”
The researchers also compared their
community-level manganese samples to public data on state-wide manganese
levels. They found comparable ranges, suggesting that overexposure to manganese
is not an isolated issue within the Holliston community.
To better understand the health risks of
exposure to manganese in drinking water, Claus Henn and Friedman recommend that
policymakers and other researchers increase monitoring of manganese in water,
conduct health studies on this exposure in communities, and consider an
enforceable standard.
“If residents are concerned about the level
of manganese in their drinking water, they should refer to these resources online from
Massachusetts Department of Environmental Protection,” Friedman says.
“It is also important to know that manganese
cannot be removed by boiling the water, and many household filters are not
effective for removing manganese from water,” she adds. “Residents should only
use filters that are capable of removing manganese, and the filtration units
should clearly state this capability.”
Reference: “Manganese in residential drinking
water from a community-initiated case study in Massachusetts” by Alexa
Friedman, Elena Boselli, Yelena Ogneva-Himmelberger, Wendy Heiger-Bernays,
Paige Brochu, Mayah Burgess, Samantha Schildroth, Allegra Denehy, Timothy
Downs, Ian Papautsky and Birgit Clauss Henn, 10 June 2023, Journal of
Exposure Science & Environmental Epidemiology.
DOI: 10.1038/s41370-023-00563-9
