FEATURE
Beginning in the late 20 th Century, PTFE also began turning up in
human blood, with the most heavily exposed populations located
on or near industrial sites, such as chemical manufacturing plants,
and the hundreds of airports, military facilities and fire departments
that store and use PFAS-containing firefighting foams.
Collectively known as per- and
polyfluoroalkyl substances, or PFAS, these
compounds now pervade almost every
aspect of modern life.
“The type of LC/MS/MS instrumentation
for this analysis costs between $250-300K
and a further $140K for the automated
96-well plate technologies for SPE for
serum testing, and a further $40K for the
automated SPE for water testing.”
Polytetrafluoroethylene (PTFE), the first
in this huge family of compounds, was
the basis for Teflon ® non-stick coatings.
Other PFAS repel water, oil and stains in
umbrellas, tents, Gore-Tex ® outerwear,
carpets and upholstery. They repel grease
and moisture in pizza boxes, fast food
wrappers, microwave popcorn bags
and pet food bags. And they have been
incorporated into everything from cell
phones to fabric softeners to Oral-B ® Glide
dental floss.
Beginning in the late 20 th Century,
they also began turning up in human
blood, with the most heavily exposed
populations located on or near industrial
sites, such as chemical manufacturing
plants, and the hundreds of airports,
military facilities and fire departments
that store and use PFAS-containing
firefighting foams.
“People are scared,” said Doug Farquhar,
JD, who analyzes environmental health
legislation for the National Conference
of State Legislators. “That’s putting a lot
of pressure on [government] agencies to
come up with some sort of response.”
PublicHealthLabs
@APHL
A second problem is contamination from
PFAS already in the laboratory. Thus,
sample introduction systems have to be
stripped of Teflon ® degassers, Teflon ® SPE
cartridges, PTFE vial caps and all other
PFAS-containing components.
Blood specimens are collected during community clinic visits
or at local patient service centers. Serum is harvested and
transferred into bar-coded blue top tubes for transport to the
Wadsworth Center for PFAS analysis. Photo: Wadsworth Center
According to the US Centers for Disease
Control and Prevention (CDC), in 2000,
the average US resident had a blood
perfluoroctane sulfonic acid (PFOS) level of
30 µg/L; 3M workers had roughly 500 µg/L.
Human exposure, in turn, has been
associated with a long list of health
problems, notably including kidney
and testicular cancers, thyroid disease,
pre-eclampsia, asthma diagnoses and
decreased antibody response to vaccines,
especially in children.
Older LC/MS/MS systems may be
incapable of detecting PFAS at the low
levels required, on the order of parts per
trillion (ppt).
And that, in turn, has created a
growing—as yet, unmet—demand for
laboratory testing to detect and measure
the chemicals in people and in the
environment.
PFAS testing: costly, complex
But laboratory testing for PFAS isn’t cheap.
Or easy. Patrick Parsons, PhD, head of
environmental health sciences at New
York’s Wadsworth Center—the state
public health laboratory—explained the
hurdles. First is cost.
“Testing for PFAS in aqueous samples
involves an extraction of the analytes
using solid phase extraction (SPE)
techniques and determination using
liquid chromatography coupled to tandem
mass spectrometry (LC/MS/MS),” he said.
APHL.org
Of course, laboratories must also have
staff experienced in mass spectrometry
and assure additional, specialized training
in trace analysis of the compounds.
And because there are few standardized
test methods for these unregulated
chemicals—and literally thousands
of possible analytical targets in a
variety of test matrices—scientists must
often develop and validate their own
testing protocols.
After all these tasks have been
accomplished, laboratories still need
approval from the Centers for Medicare
& Medicaid Services before clinical test
results can be reported to patients. “This
requires a substantial amount of work
to document the validation studies
performed and to develop the protocols
that meet clinical quality standards,”
said Parsons.
Analyzing drinking water for PFAS,
he said, “also requires a substantial
effort to document validation and to
develop the detailed protocols that meet
environmental quality standards.”
Winter 2019 LAB MATTERS
5