health impacts of emerging contaminants: a look at genx ... · health impacts of emerging...

Health Impacts of Emerging Contaminants: A look at GenX and beyond

Jane Hoppin, ScDAssociate Professor, Biological Sciences

Deputy Director, CHHE

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Outline

Emerging ContaminantsWhat are they?

GenX backgroundPotential Health Outcomes

Emerging ContaminantsUsually not “new” chemicals

Newly measured or newly foundNot regulated

Lack of exposure dataWhat are the chemicals?How do people get exposed? Water? air?

Lack of toxicology dataHalf livesPotential health effects

Lack of human health information

No specific limit in environmental regulations.Sparse knowledge about how they behave in the environment.Little known about their effects on human health and environment.

Significant challenge for regulatory agencies.How to prioritize? Research? Minimize impacts? Communicate?

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What do we mean when we say Emerging Compounds?

Unknown Characteristics of “Emerging” Fluorinated Compounds

Actual identities of alternatives unknown in industrial sectors and geographical regions that are not well regulated

Data on environmental and human health effects are incomplete (at best) and more often nonexistent

Data on degradability, bioaccumulation, and toxicity (environmental and human) are incomplete (at best) or completely lacking

Information on production volume and environmental emissions not available

Wang et al. Environment International 2013, 60, 242−248

Largest watershed in NCSupplies ~1.5M people with drinking waterLarge ~25 mile long estuary below WilmingtonLarge amount of industry along portions of the river

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PFAS in River AND Drinking WaterDetlef Knappe,NCSUMark Strynar, USEPAAndy Lindstrom, USEPA

Wilmington Star News, June 7, 2017

Community forums with local scientists, environmental advocates, utility representatives, DEQ / DHHS, academia, and public health experts

Intensive media coverage, including state-wide and national attention

Considerable interest by local, state, and national elected officials

Community Response

PFAS Chemicals

Per- and poly-fluoroalkyl substancesEnvironmentally persistent

Don’t break down

Some of the chemicals are measured in most peoplePFOA and PFOSNew chemicals we don’t know much about

Two types of PFAS have been heavily studied “Legacy Compounds”

Perfluorooctane sulfonate (PFOS)

Perfluorooctanoic acid (PFOA / C8)

Common uses:Goretex, Teflon

Common uses: Firefighting, stain repellent

Presenter

Presentation Notes

PFCs work well as surfactants because of the hydrophilic acid head and hydrophobic carbon-fluorine tail that can not only repel water but also fats and oils. The hydrophobic/hydrophilic characteristic, as well as high water solubility and low volatility, contribute to the presence of PFCs in all aquatic environments and even in rain water.

Non-stick coatings

Grease- and oil-resistant coatings for paper products

Water repellent fabrics

Stain-resistant coatings for fabrics, carpets, and leather

Firefighting foams

PFASs are released into the environment by:

the manufacturing process, and

the use of products containing PFASs

http://www.sixclasses.org/

Presenter

Presentation Notes

Firefighting agents are probably one of the products that contribute the most to PFC emissions because of the direct introduction of PFCs into the environment when extinguishing fires. Coated textiles are another important source since PFCs can be released during cleaning or through wear.

Trends in PFAS Serum Levels in US

Sagiv et al. Environmental Science & Technology 2015, 49, 11849−11858

GenX = C3 Dimer Acid = C6HF11O3

GenX is a trade name for a man-made and unregulated chemical used in manufacturing nonstick coatings and for other purposes.

In a family of chemicals known as per- and poly- fluorinated alkyl substances (PFAS)Produced and emitted by one company in NC – Chemours (formerly Dupont)Has been discharged into the Cape Fear River for 30+ years (since 1980)Until the past couple of years, labs couldn’t measure it.DHHS Public Health Goal = 140 ppt in water

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GenX – Not a Generational Thing

Presenter

Presentation Notes

So.. What is Genx? No, its not just a generational thing. C3 Dimer Acid or C6HF11O3. GenX is a trade name….. EPA monitoring, 2013-2015 via the Third Unregulated Contaminant Monitoring Rule (UCMR) Found 28 chemicals EPA and NCSU, 2014-2016, study PFOA, PFOS and other per- and poly-fluorinated chemicals in the Cape Fear River. Research findings published in Nov. 2016 on PFOA/PFOS, GenX and other related chemicals attributed to the Chemours (formerly DuPont) facility just south of Fayetteville, NC. With growing concerns about the potential public health impacts, 11/14/18, EPA published draft reference doses and draft toxicity assessments for GenX compounds and perfluorobutane sulfonic acid (PFBS).

History of Contamination

1980 - Contamination begins with Dupont – GenX released as a byproduct

Around 2000 - DuPont begins manufacture of Teflon using C8 (PFOA); GenX will be its replacement

2009 Parkersburg consent order requires all wastewater from GenXmanufacture is captured; it’s still being released as a byproduct

Credit: WUNC

GenXFirst, a byproduct of vinyl ether productionNext, an identified ingredient to replace PFOA in Teflon production

Identity originally protected as Confidential Business Information (CBI)

Still persistent, still toxic, but less bioaccumulative than C8

DuPont studies found effects on rats similar to C8, including possible endocrine/immune disruption, enlarged livers and kidneys, and cancer

Approved by the EPA, no further testing required

Sun et al. Environmental Science & Technology Letters 2016, 3, 415−419

Not just GenX:

Family of Per- and PolyfluorinatedChemicals

Legacy PFAS with GenX in Cape Fear River Basin

Sun et al. Environmental Science & Technology Letters 2016, 3, 415−419

Other similar substances occur at much higher concentrations than legacy PFASs and GenX

Sun et al. (2016) ES&T LettersGenX

GenX Emerging PFASs

Presenter

Presentation Notes

Bill, these concentrations are estimated from the GenX response as we do not yet have authentic standards apart from GenX

GenX concentrations after fluorochemical manufacturer announced on 6/21/2017 that it stopped discharging GenX

0

100

200

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500

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800

6/21 6/26 7/1 7/6 7/11 7/16 7/21 7/26 7/31 8/5

Gen

X Co

ncen

trat

ion

(ng/

L)

Finished Water

NC Health Goal140 ng/L

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What are the potential health effects of GenX?

We have some data for humans

We often rely on animal models to inform these…

Once we are exposed to PFASs, some can stay in the body for a long time

Compound Half-life(Human)

Half-life(Female Rat)

Half-life(Male Rat)

PFOA (C8) 3.8 years 4 hours 6 days

GenX ?????? 2.9 days

But animal models don’t

seem to be great predictors here.

Compound PFOA (C8) PFOS PFHxA

(C6)

Half-Life(Human) 3.8 years 5.4 years 32 days

C6 is the most similar to GenX,

and gives us our best guess at

its half-life

Human Health Data Available for Related CompoundsC8 Science Panel Study (Parkersburg, WV)PFOA probably associated with:

Elevated cholesterolUlcerative colitisThyroid diseaseTesticular and kidney cancerPregnancy induced hypertension

Mainly Adults, >45,000 people

PFAS Health EffectsHealth outcomes in children (Rapazzo et al, 2017)

DyslipidemiaImmune function (vaccine response and asthma)Renal functionAge at MenarcheBirth weight (Bach et al, 2015)

Thyroid function (TSH) (Ballesteros et al, 2017)Pregnant WomenBoys

Mainly PFOA and PFOS

December ‘17 – on going

• Analysis continued

July ‘17

• First CommunityMeeting

August ‘17

• Grant Submitted

November ‘17

• Grant Funded• Data Collection

April ‘18

• Water report-back

Designed to answer community questions about GenX and related PFAS exposure

Are PFAS detectable in my body?What predicts PFAS in my body?Are there health effects associated with PFAS?

Funded by NIEHS through their time sensitive grants program.

GenX Exposure Study: Responding to Community Concerns

May ‘18

• New enrollment• Resampling

Oct ‘18

• Clinical report-back letter

Nov ‘18

• PFAS blood report-back

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Home and Clinic VisitHome visit

collected tap water

Clinic visitblood drawurine sample collectionquestionnaireheight and weight measurement

Nov 2017 at New Hanover County Health Department

May 2018 at MLK Center27

Presenter

Presentation Notes

Home visit for tap water collection Clinic visit: Blood draw – PFAS analysis and Lipids, Thyroid Function, Comprehensive Metabolic Panel Urine sample collection Questionnaire Height and Weight Measurement

Who Participated?

Sample Collection inNovember 2017May 2018

344 individuals289 adults55 children (6-17 years)

Racially diverse76% White10% Black9% Hispanic5% Other

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

1-5 6-10 11-19 20+

Years in Cape Fear Region

Children Adults

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What’s in the Water?

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PFAS we tested for

Newly identified“Legacy”11. GenX12. Nafion byproduct 213. PFMOAA14. PFO4DA15. PFO3OA16. PFO2HxA

1. PFBA2. PFPeA3. PFHxA4. PFHpA5. PFOA6. PFNA7. PFDA8. PFBS9. PFHS10. PFOS17. 6:2 FTS

(tinyurl.com/GenXstudy)

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Presenter

Presentation Notes

7 recently identified fluorochemicals Some of which were designed as replacements for the legacy chemicals For example, we know that GenX was created as a replacement for PFOA Some of these are not replacements, but they are byproducts of the fluorochemical manufacturing process We know very little about their behavior and even less about their health effects but it’s thought that GenX is less likely to accumulate in humans because of differences in its chemical structure compared with PFOA These 17 fluorochemicals were chosen based on what other scientific researchers have studied, and based on knowledge of Chemours manufacturing process

Groundwater source

Cape Fear River source

Similar GenX concentrations in Sweeney treated water

NC health value (140 ng/L)

Treated water from Sweeney plant,Oct 2-Dec 5, 2017

GenX(ng/L)

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Presenter

Presentation Notes

A part per trillion is one droplet of water in that pool,” she said. “So 140 parts per trillion would be about 140 droplets.” Extrapolated out to other examples, 140 ppt would be about 0.35 seconds in a lifetime of 78 years. And the health level set for GenX is extremely low. For example, the U.S. Environmental Protection Agency set 10,000 ppt as the acceptable level of concentration for arsenic -- a highly toxic chemical element -- in drinking water. And Brander noted that GenX has a similar makeup to other perfluorinated compounds like C8, the toxic chemical compound GenX replaced. Very low or non-detect GenX levels in groundwater samples GenX levels of all water samples below the action limit Why are there still measurable levels of GenX even after Chemours reported to stop discharging it? Could be surface water recharge from contaminated groundwater These groundwater values are not representative of all groundwater quality, especially private wells surrounding Chemours. We know that GenX has been measured in private wells surrounding Chemours. It could be GenX in sediments is a continuous source for the water

Other fluorochemicals were present

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No pure chemicals were availableAverage mass

spectrometer response

Presenter

Presentation Notes

In addition to GenX, we found other fluorochemicals, including Nafion byproduct 2, perfluoro-2-methoxyacetic acid (PFMOAA), and perfluoro(3,5-dioxahexanoic) acid (PFO2HxA) in water samples. While we are confident of whether each of these chemicals was present or not, the chemical standards were not available to determine an exact value. In addition to GenX, we found other fluorochemicals such as a byproduct of Nafion (Nafion byproduct 2), perfluoro-2-methoxyacetic acid (PFMOAA), and perfluoro(3,5-dioxahexanoic) acid (PFO2HxA) in water samples. Results for these chemicals are considered semi-quantitative estimates (as described below). The average “response” of the laboratory instrument across all samples was higher for these chemicals than GenX’s (see Figure 3). The word average means a result that is typical or “in the middle” of the water results from other homes. There are currently no public health goals for Nafion byproduct 2, PFMOAA, or PFO2HxA. Thinking about Nafion byproduct 2 and PFMOAA While we didn’t have standards for analysis in water, we will have standards for their analysis in blood

What about blood?

Did we find GenX in blood?No, we did NOT find GenX in blood

Method reporting limit: 2 ng/mL GenX

Sampled ~5 half lives after discharge stopped 50 ng/L GenX in water in Nov 2017<10 ng/L GenX in water in May 2018

NC Dept of Health and Human ServicesGenX NOT in blood from 30 people livingnear Chemours plant

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Presenter

Presentation Notes

We did not find GenX in blood Our method reporting limit was 2 ng/mL Which means that if GenX was present in the blood at 2 ng/mL or greater, we would have been able to see it and determine how much was there In retrospect, the fact that we didn’t see GenX was not surprising We sampled blood about 5 months after Chemours stopped discharging GenX to the Cape Fear River There was still GenX in the tap water when we collected blood and urine, but the levels were much lower Five months would be about 5 half lives if the half life for GenX is about 30 days whichw as our best guess In five months, the levels in the blood would have decayed below what our method could measure Our results are consistent with an investigation from NC Dept of Health and Human Services They looked for GenX in the blood of 30 people living near the Chemours Plant who rely on private wells They did not find GenX in the blood These data together suggest that GenX doesn’t stay in the body for long

Newly identified PFAS in Wilmington blood

1. Nafion byproduct 2 (99%)

2. PFO4DA (98%)

3. PFO5DoDA (87%)

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OF

FO

FF

OF

FO

FF

OF

FF

OHS

O

O

F

F

F

F

O FF F

F

F FO F

F FF

OH

OF

FOF F

OF

FOFF

OF

FF

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Presenter

Presentation Notes

We four other Chemours PFAS in the blood of a majority of our participants We found Nafion byproduct 2 in 99% of blood samples PFO4DA in 98% of blood samples PFO5DoDA in 87% of blood samples These were all relatively long chain compounds They have multiple ether linkages

How do we know about legacy PFAS in US residents?

Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES)

PFOA, PFOS, PFHxS, PFNA, PFDA results are publicly-available

1999-2000 survey (higher exposure)2015-2016 survey (lower exposure)

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Presenter

Presentation Notes

But how do we know about legacy PFAS in US residents? The Centers for Disease Control and Prevention has the NHANES survey. They collect blood samples from a group of people in the United States every year. The people they test should be representative of the US population as a whole. They measure for some of the legacy PFAS that we measured for. They make their data publically available. We can look at data from 1999 to show us the levels in blood in the United States back when PFAS exposure was higher We can also look at data from 2015 to show us blood levels in the United States recently.

PFOA in US residents’ blood

50%

75%

95%

25%

5%

US 1999 (n=1,591)

US 2015 (n=2,170)

Wilmington, NC(n=344)

PFOA concentration(ng/mL)

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Presenter

Presentation Notes

These are PFOA concentrations in US residents in 1999 Most of the data is between 2 and 10.5 ng/mL

50%

75%

95%

25%

5%

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PFOA in US residents’ blood

US 1999 (n=1,591)

US 2015 (n=2,170)

Wilmington, NC(n=344)


Presenter

Presentation Notes

There was a push to phase out PFOA production in the US in the early 2000s The levels of PFOA in blood in the US dropped substantially PFOA is not longer produced in the US

50%

75%

95%

25%

5%

Elevated PFOA in Wilmington blood, 2017

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US 1999 (n=1,591)

US 2015 (n=2,170)

Wilmington, NC 2017(n=344)


Presenter

Presentation Notes

Here are the PFOA serum levels for our Wilmington cohort The median PFOA level in Wilmington is similar to the median for the US about 20 years ago, before PFOA was phased out Half of our study participants have more PFOA in their blood than 95% of US residents

Why is there elevated PFOA in Wilmington blood?

Historical exposure to high PFOALimited data in lower Cape Fear, 2002-2009

Continued exposure to low PFOA18 ng/L PFOA in Wilmington tap waterUpstream sources

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Presenter

Presentation Notes

Admittedly, we do not know the answer We are working to figure this out We don’t know but we’re working to figure that out It could be that people in Wilmington were exposed to high levels of PFOA in the past It’s possible we’re seeing that exposure still decaying in the body There is very limited data on PFOA in Wilmington drinking water between 2002 and 2009 2002 is when the Chemours plant in Fayetteville began producing PFOA 2009 is when GenX began replacing PFOA Another possibility is that, instead of a high exposure, there is an ongoing exposure to low levels of PFOA In the tap water samples we collected from our study, across 200 homes, the median was 18 ng/L

PFOA PFHxS PFNA PFDAPFOS

Bloo

d co

ncen

trat

ion(

ng/m

L)

Other elevated legacy PFAS in Wilmington

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Presenter

Presentation Notes

What about the other legacy PFAS? Found higher levels of PFOA, PFOS and PFHxS in Wilmington blood than national averages PFOA and PFOS are in Wilmington drinking water but < 70 ng/L GenX replaced PFOA, still see PFOA but not GenX Some evidence for higher PFAS exposure in the CFR watershed (not just Wilmington)

Nafion byproduct 2

PFO4DA

PFO5DoDA

Median blood concentration for 44 participants (ng/mL)

Nov

embe

r 201

7

May

201

8

Blood concentrations of newly identified PFAS decreased after six months

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Presenter

Presentation Notes

The concentrations of PFO4DA and PFO5DoDA also decreased substantially over six months.

Legacy PFAS levels didn’t change over six months

Median blood concentration for 44 participants (ng/mL)

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PFOS

PFOA

PFHxS

PFNA

PFDANov

embe

r 201

7M

ay 2

018

Presenter

Presentation Notes

The levels of the other chemicals did not change much We expected not to see much change because there’s been more research on these chemicals and they do last for years in the body.

What about the air?

Fayetteville, NC near chemical plant

Emerging Compounds – GenX Case History

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Early-mid 2017: focus on surface water issues

Mid 2017: groundwater issues discovered

Mid-late 2017: air emission contributions

Presenter

Presentation Notes

Davis et al. Chemosphere 67 (2007) 2011–2019


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Private groundwater wells

>140 ppt GenX10-140 ppt GenXND GenX

Emerging CompoundsDAQ’s investigation involving GenX and other PFAS from Chemours

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Department of Environmental Quality

GenX emissions data Started with only estimatesRequired stack testsMethod developmentFirst of its kind measurements

Chemours 2016 emissions estimates as originally reported to

DAQ

Chemours revised 2016 emissions estimates as

of October 2017

Latest calculations of annual emissions,

including stack test measurements

66.6 lb/yr 594 lb/yr 2302.7 lb/yr

Presenter

Presentation Notes

When we first suspected that air emissions might be contributing to the groundwater issues being found near the source of this unique emerging compound, we only had emission estimates. That information – the estimates provided by the facility - steadily increased as additional recalculations were performed. Eventually, DAQ required the company to conduct stack tests to get actual emissions measurements, however, there was no “off-the-shelf” stack test method for this compound. DAQ worked for months with the facility, their stack testing contractor and EPA to get to a point of agreement on the stack testing method and approach. Early this year… in January and February actual stack testing was conducted at the facility… producing emissions measurements of the GenX compounds for the first time. The data presented in the table shows how this situation has evolved… And now, based on a blend of actual emissions measurements from some of the primary emission sources… and estimates from other emission sources that have not been tested… we believe the annual emissions of the GenX compounds are over 2300 pounds per year.


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Air Emissions Testing or “Stack Testing”• Target compound – C3 Dimer Acid (GenX)• Week of:

• January 8 – PPA & Vinyl Ethers (VE) North• January 22 - PPA & VE North• February 26 - PPA & VE South• March 19 - VE North, Polymers,

Semiworks• April 3 – VE South & VE North for HFPO• April 23 – VE North HFPO• May 14 – Polymers for E1• June 11 – PPA & VE North Carbon bed• July 16 – PPA scrubber efficiency

• VE North carbon bed & Scrubber• July 23 – PPA scrubber &

• carbon bed efficiency

Future testing:August 20 & 27 Scrubber efficiency

No agreement on appropriate methods.But, we knew we could measure it in water.Why not collect rainwater samples to get a sense of atmospheric contributions groundwater issues?Purchased temporary rain collection equipment.Used lab protocols to prepare equipment.

What about ambient air measurements???

Presenter

Presentation Notes

How much of this compound is in ambient air? Not much agreement from the experts on methods… but there was one thing we knew for sure… that was we can measure this stuff in water.

Emerging CompoundsDAQ’s investigation involving GenX and other PFAS from Chemours

Summary of facts:

The measured air emissions of GenX compounds are significantly higher than previously understood and reported.

DAQ has measured GenX deposition through rainfall as far as 20 miles from the facility.

The evidence of atmospheric deposition of GenX shows a geographic footprint that is similar to the detection of GenX in groundwater samples.

Presenter

Presentation Notes

…And because GenX is not a naturally occurring compound and there are not other producers or users of GenX in NC, the data demonstrate groundwater violations being caused by air emissions of GenX.

GenX Exposure Study: Fayetteville

Focusing on both air and water exposuresDust samplesWristband samplesWater Samples

Blood and UrineNon-targeted PFAS

Enrolled participants in February 2019Analyses ongoing

Widespread Impacts

Surface water discharge contaminated the drinking water supply for >250,000 people

Airborne pollutants further impact surface water, groundwater, agriculture, fish, and even honey

Well testing to date shows 763 private wells are contaminated

Rainwater contaminated as far away as Wilmington (>70 miles)

Credit: Wilmington Star News

Lingering Questions

How long were people exposed?GenX released to the river since 1980When did Nafion byproduct 2 start being released?What other chemicals?

How can we estimate exposure levels for chemicals with short half lives?Are the chemicals in the air the same as in the river?Now that exposure sources have been controlled, how can we estimate exposures?Exposure is not just to one chemical, but a mixture of chemicals

Next Steps

Analyze collected samplesAre the chemical exposures the same in Wilmington and Fayetteville?

Look at health outcome dataThyroidCholesterolLiver functionBMIRespiratory symptoms and diseaseCytokine response

GenX Exposure Study TeamNC State

Jane Hoppin, PIDetlef KnappeNadine KotlarzKaty MayRob Smart

ECUDavid CollierJamie DeWittSuzanne Lea

EPAAndrew LindstromJames McCordMark Strynar

New Hanover County Health Department

Phillip TarteKatelyn Matney

Cape Fear River WatchKemp BurdetteMadi PoleraAmanda BoomershineLarry Cahoon

Community Science Advisory Panel

Funding: NIEHS R21 R21ES029353CHHE P30ES025128Matching Funds from NC Policy Collaboratory 58

GenX Exposure Study: Responding to Community Concerns

Community wants to know:Is GenX detectable in me?

What factors influence GenX concentration?

Is GenX associated with health effects?

1980: Chemours begins discharging GenX, a perfluoroalkyl substance (PFAS)

2017: GenX detected in Cape Fear River, City of Wilmington’s finished drinking waterNow: Exposure reduced, but community concerned about health impacts

The GenX Exposure StudyPartners: Cape Fear River Watch, New Hanover County Health Dept.Enrolled: >300 residents, ages 6+, November 2017Measuring: GenX in drinking water, blood, urineCommunication: Utilizing Community Science Advisory Panel for report backPI: Hoppin R21 ES029353

Wilmington, NCSun et al. ES&T letters 2016

health impacts of emerging contaminants: a look at genx ... · health impacts of emerging...

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