Pine needles tell the story of PFAS in North Carolina

Date:
February 22, 2022
Source:
North Carolina State University
Summary:
The humble pine tree is more than just a common sight in North
Carolina - - it's also a handy tool for monitoring the proliferation
of per- and polyfluoroalkyl substances (PFAS) in our state over
time.



FULL STORY ==========================================================================
The humble pine tree is more than just a common sight in North Carolina
-- it's also a handy tool for monitoring the proliferation of per-
and polyfluoroalkyl substances (PFAS) in our state over time.


========================================================================== Researchers from North Carolina State University used historical and
current pine needle samples to trace the presence and concentrations of
over 70 different types of PFAS in six N.C. counties from 1961 to the
present. The findings are a snapshot of the evolution of PFAS in the
state over a 50-year period.

Why pine needles? "They're everywhere in the state and free, so it's
very easy to sample numerous locations and time points without having
to build and retrieve expensive sampling equipment," says Erin Baker,
associate professor of chemistry at NC State and co-corresponding author
of the work.

As for the needles themselves, the waxy coating that protects them from
the elements also acts as an efficient trap for airborne contaminants
such as PFAS.

And since pine trees drop their needles on an annual schedule, researchers
can be certain about the points in time they're looking at when they
take samples.

Baker, NC State colleague Scott Belcher, and Ph.D. candidate and lead
author Kaylie Kirkwood obtained 60 pine needle samples from sites in
Durham, Wayne, Cumberland, Robeson, Onslow and Brunswick counties.



==========================================================================
For historical comparison, they used 15 pine needle samples from the NC
State and Duke University herbaria, looking specifically at samples from
those same counties dated from 1961 to the present.

"We were focused primarily on locations we have modern data for,
as well as locations that are associated with PFAS, like airports,
firefighter training sites and chemical plants like the Chemours
facility," says Belcher, an associate professor of biology at NC
State and co-corresponding author of the research. "We took samples
at those sites and at sites three to 11 miles away for comparison."
The researchers analyzed the samples by performing liquid chromatography,
mass spectrometry, ion mobility spectrometry and fragmentation studies
on each one.

This multi-dimensional approach ensured accuracy when distinguishing
between molecular structures of the different chemicals.

The results are a snapshot history of a half century of PFAS in central
and eastern North Carolina.

"We were able to see when the new, shorter chain chemicals were
introduced, when old ones were phased out, and where specific PFAS were
being used -- we could trace actual, real-time changes in contamination," Kirkwood says. "And we were able to see the exposure gradients for
these chemicals -- how the concentrations fell off from high levels at
the source of the contamination versus lower levels farther away."
The researchers hope that this work will pave the way for other
researchers to use passive sampling to monitor the spatial and temporal distribution of PFAS.

"This is way bigger than North Carolina -- it's applicable to sites all
over the world," Baker says. "Beyond N.C. and beyond pine needles, this
shows the capability of plants with waxy coatings to serve as sentinels
of environmental contamination." The research appears in Environmental
Science & Technology and was supported by the National Institutes of
Health under grant numbers T32 GM00876, P30 ES025128, P42 ES027704 and
P42 ES031009, and the U.S. Environmental Protection Agency under grant
STAR RD 8400320.1. NC State professor of biological sciences David Reif,
Ph.D. student Jonathon Fleming, and former undergraduate student Helen
Nguyen, also contributed to the work.

========================================================================== Story Source: Materials provided by
North_Carolina_State_University. Original written by Tracey Peake. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kaylie I. Kirkwood, Jonathon Fleming, Helen Nguyen, David M. Reif,
Erin
S. Baker, Scott M. Belcher. Utilizing Pine Needles to Temporally
and Spatially Profile Per- and Polyfluoroalkyl Substances (PFAS).

Environmental Science & Technology, 2022; DOI:
10.1021/acs.est.1c06483 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220222135200.htm

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