Most scientists agree that the water
quality in Narragansett Bay and the waters that flow into it is quite good and
getting better. But that’s not true by every measure. In fact, a University of
Rhode Island oceanographer who studies chemical pollutants in the oceans found
that a New Jersey river designated a Superfund site is actually much cleaner
than some water bodies in Rhode Island when it comes to a recently banned group
of pollutants called perfluorinated compounds.
According to URI Professor Rainer Lohmann, perfluorinated compounds have long been used in the production of
Teflon and the non-stick coatings on pizza boxes and popcorn bags, as well as
in the waterproof coating added to some clothing.
“Everyone
has the stuff in them at low concentrations,” Lohmann said.
The
compounds are also very good at extinguishing fires fueled by gasoline and
other fuels, so the foams that airports use to fight airplane fires contain the
chemicals. While few such fires occur each year, the foams are used regularly
during fire training exercises at every U.S. airport, where the chemicals
percolate through the ground and run off into nearby streams, ponds and bays.
“The problem with these compounds is
that they don’t break down,” Lohmann said. “They bioaccumulate, so they aren’t
good for our health. They increase in concentration as they go up the food
chain – and people are at the top of the food chain, along with polar bears,
bald eagles and other large animals.”
Lohmann said that the Environmental
Protection Agency required that production of the worst perfluorinated
compounds be phased out by 2015. But many manufacturers of the compounds have
gotten around the ban by making minor changes to their chemical composition,
which makes them only slightly better than the banned versions.
“And just because production stops
doesn’t mean the compounds go away,” Lohmann added. “They continue to leach
into our groundwater and all kinds of other things. So we will continue to have
the legacy of them, probably for decades to come.”
Lohmann and colleagues at Harvard
University analyzed water samples from 28 water bodies in Rhode Island and nine
sites along New Jersey’s Passaic River and published their results last month
in the scientific journal Environmental Science and Technology Letters. The Rhode Island samples were collected by
volunteers participating in the URI Watershed Watch program, which monitors
water quality at 200 sites around the state.
“I’ve taken water samples from
Narragansett Bay for years, and we’ve always found these compounds in the 1 to
5 nanoliter range, which isn’t huge but also isn’t trivial,” he said. “I was
curious about why we’re still finding them.”
While his analysis of the latest
water samples did not detect the compounds at some sites, like the Narrow River
and several rural locations, concentrations were high in some samples collected
from northern Rhode Island and in Warwick. Lohmann said all of the samples with
high concentrations of perfluorinated compounds were associated with airports,
textile mills, wastewater treatment facilities, and industrial metal plating
operations, the latter of which use solvents containing the compounds.
The samples from New Jersey all
contained low levels of the chemicals.
“That was a big surprise to us,
because most of the time, Narragansett Bay is a fairly clean water body.
Normally when we compare it to the Passaic River, we’re cleaner by an order of
magnitude or two. But not in this case,” Lohmann said.
The EPA has set a maximum threshold for
perfluorinated compounds of 70 nanograms per liter in drinking water. And while
none of the Rhode Island sites exceeded that value – the highest was 47 near
T.F. Green Airport – Lohmann said that many states and countries have set lower
limits, and several of his colleagues think that “70 is far too high” to be
safe.
The concern is that exposure to the
compounds, especially high exposure over long periods of time, can lead to
several kinds of cancer. Epidemiology studies suggest that exposure can also
lead to immune system deficiencies and contribute to obesity via a decline in
liver function.
The good news, according to Lohmann,
is that since the compounds were not detected in several samples, then “clearly
you can get to almost zero. It means that Rhode Island has a number of point
sources that potentially could be targeted for reduction,” he said. “If DEM
wanted to, they could probably identify where those compounds are coming from
and maybe try to reduce their emissions. That would be a good thing for the
bay.”
This article first appeared in EcoRI.org on October 7, 2016.
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