DEVELOPMENT OF A USER FRIENDLY FRAMEWORK FOR GEOSPATIAL - - PowerPoint PPT Presentation

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DEVELOPMENT OF A USER FRIENDLY FRAMEWORK FOR GEOSPATIAL - - PowerPoint PPT Presentation

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DEVELOPMENT OF A USER FRIENDLY FRAMEWORK FOR GEOSPATIAL IDENTIFICATION OF POTENTIAL PFAS SOURCE ZONES Jennifer Guelfo, PhD June 12, 2017 1 PRESENTATION OVERVIEW PFAS PFAS in U.S. Source Zone Overview Drinking H 2 O EvaluaJon

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DEVELOPMENT OF A USER FRIENDLY FRAMEWORK FOR GEOSPATIAL IDENTIFICATION OF POTENTIAL PFAS SOURCE ZONES

Jennifer Guelfo, PhD June 12, 2017

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PRESENTATION OVERVIEW PFAS Overview Source Zone EvaluaJon PFAS in U.S. Drinking H2O

  • Terminology/

chemistry

  • Uses/regulaJon
  • UCMR3 data
  • Knowledge

gaps

  • Key PFAS sources
  • GeospaJal eval.

framework

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PFAS OVERVIEW: TERMINOLOGY & STRUCTURE Perfluoroalkyl carboxylates:

Examples: m=2 PFBA m=4 PFHxA

m=6 PFOA

Perfluoroalkane sulfonates:

Examples: m=3 PFBS m=5 PFHxS

m=7 PFOS

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Per = fully fluorinated alkyl tail.

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Perfluoroalkyl carboxylates:

Examples: m=2 PFBA m=4 PFHxA

m=6 PFOA

Perfluoroalkane sulfonates:

Examples: m=3 PFBS m=5 PFHxS

m=7 PFOS

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Polyfluoroalkyl substances:

m=5 6:2 FtS m=7 8:2 FtS

F F F F F m H H 2 S O O O-

Poly = parJally fluorinated alkyl tail.

PFAS OVERVIEW: TERMINOLOGY & STRUCTURE

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Perfluoroalkyl carboxylates:

Examples: m=2 PFBA m=4 PFHxA

m=6 PFOA

Perfluoroalkane sulfonates:

Examples: m=3 PFBS m=5 PFHxS

m=7 PFOS

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Polyfluoroalkyl substances:

m=5 6:2 FtS m=7 8:2 FtS

F F F F F m H H 2 S O O O-

Per

+

Poly = Per & polyfluoro alkyl substances (PFAS) PFAS OVERVIEW: TERMINOLOGY & STRUCTURE

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PFAS OVERVIEW: TERMINOLOGY & STRUCTURE

Buck, Robert C., et al. "Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classificaJon, and origins." Integrated environmental assessment and management 7.4 (2011): 513-541.

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PFAS OVERVIEW: TERMINOLOGY & STRUCTURE

3000 + new PFASs+ transformaJon products = relevant PFASs

Buck, Robert C., et al. "Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classificaJon, and origins." Integrated environmental assessment and management 7.4 (2011): 513-541.

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ElectronegaJvity = strong, polar covalent bond

ResulJng PFAS properJes:

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Small size of fluorine = F shields C

  • Strong acidity (low pKa)
  • Thermal stability
  • Chemical stability
  • Hydrophobic & lipophobic
  • Surfactant

PFAS OVERVIEW: CHEMISTRY & USES

Kissa, Erik, ed. Fluorinated surfactants and repellents. Vol. 97. CRC Press, 2001. Banks, Ronald Eric, Bruce E. Smart, and J. C. Tatlow, eds. Organofluorine chemistry: principles and commercial applica:ons. Springer Science & Business Media, 2013.

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ElectronegaJvity = strong, polar covalent bond

ResulJng PFAS properJes:

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Small size of fluorine = F shields C

  • Strong acidity (low pKa)
  • Thermal stability
  • Chemical stability
  • Hydrophobic & lipophobic
  • Surfactant

PFAS OVERVIEW: CHEMISTRY & USES

Kissa, Erik, ed. Fluorinated surfactants and repellents. Vol. 97. CRC Press, 2001. Banks, Ronald Eric, Bruce E. Smart, and J. C. Tatlow, eds. Organofluorine chemistry: principles and commercial applica:ons. Springer Science & Business Media, 2013.

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Advisory or standard Source

70 ng/L ∑ PFOA, PFOS

USEPA LHA

20 ng/L ∑ PFOA, PFOS Vermont

14 ng/L PFOA, 10 ng/L PFNA New Jersey

Why the differences?

  • VT: same RfD as EPA, different

DW ingesJon

  • NJ: different RfD based

different endpoint- liver weight

  • vs. developmental delay.

RfD * Body Wt. DW ingesJon RelaJve Source ContribuJon * = Water Quality Standard 70 ng/L: individually or in combinaJon

Drinking Water Health Advisories for PFOA, PFOS

PFAS OVERVIEW: REGULATION

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Informa:on courtesy of Dr. David Klein

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PFAS IN THE U.S.: UCMR3 DATA

EPA UCMR Data 2013-2015:

  • 4120 Systems > 10,000
  • 800 systems ≤ 10,000
  • No private systems
  • MulJple PFAAs/sample
  • 4% detecJon rate (~200);

which are ‘impacted’?

  • 64 systems > LHA
  • 122 systems > NJ (but

MRL=20 ng/L)

  • 151 systems > VT

Data reflect only samples with PFAA detec:ons

Hu, Xindi C., et al. "DetecJon of poly-and perfluoroalkyl substances (PFASs) in US drinking water linked to industrial sites, military fire training areas, and wastewater treatment plants." Environmental science & technology leCers3.10 (2016): 344-350.

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EPA UCMR Data 2013-2015:

  • [PFAAs] 10-7000 ng/L
  • [PFOS] = max overall
  • PFOA most frequent detect
  • Groundwater in ~80% of

detects

  • 2818 GW/GU systems,

2691 SW systems

  • Average GW [PFAA]tot > SW

[PFAA]tot

  • Overall: GW % detect > SW

% detect

PFAS IN THE U.S.: UCMR3 DATA

G = groundwater S = Surface water O = DetecJon rate (right axis)

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Is UCMR representa]ve?

  • No UCMR detects in VT, including

Bennington, Pownal but impacts present

  • Impacts present in areas not sampled

(e.g. Hoosick Falls, NY)

  • 0.5% of small systems in U.S. sampled

(Hu, 2016)

  • [PFAA]S > [PFAA]L but S = small sample

size

PFAS IN THE U.S.: UCMR3 DATA

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Data warrant targeted screening of community, private groundwater wells; need efficient, effec]ve design of well screening programs.

PFAS IN THE U.S.: UCMR3 DATA

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Finding sources:

  • Numerous uses/applicaJons =

numerous potenJal sources

  • Low target concentraJons =

small releases, indirect sources relevant

  • Unconsolidated or missing

informaJon on current, historical sources

May cause: inefficient sampling plans, failure to ID all relevant sources, inability to determine source, increased Jme required to reduce risks to human health, environment

PFAS IN THE U.S.: KEY CHALLENGES

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Data Sources:

  • Landfills
  • Fire staJons
  • Fire Training Areas
  • Airports
  • Manufacturing faciliJes

1960-2012

  • IdenJfied industrial codes

known to use or produce PFAS

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Hazard = (Release Prob.) * (Years of OperaJon)

PFAS SOURCE ZONES: GEOSPATIAL FRAMEWORK

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Raster Grid and Points PFAS Hazard Map

City of Providence

How do hazards compare to groundwater vulnerability?

PFAS SOURCE ZONES: GEOSPATIAL FRAMEWORK

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Risk = Hazard * Vulnerability

Vulnerability based on proximity to:

  • Drinking water aquifers
  • Wellhead protecJon areas

GW Recharge

Hazard vs. Risk:

  • ↑ Hazard in pop. centers but…
  • GW not classified for drinking
  • ↑ Risk in rural areas for

small, community scale systems

PFAS SOURCE ZONES: GEOSPATIAL FRAMEWORK

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Wells = exposure potenJal

PFAS SOURCE ZONES: GEOSPATIAL FRAMEWORK

Buffered community wells

GeospaJal future work:

  • Assist in sample point

selecJon, sampling, analysis

  • Ground truth geospaJal

analysis

  • Pending source data

availability, implement in regions w/GW data

  • Key quesJons:
  • Can we evaluate based on

potenJal for release vs. known use/release?

  • RelaJve importance of locaJon

info for each source type

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Brown University Superfund Research Program

  • Dr. Sco{ Frickel
  • Thomas Marlow
  • Amy Parmenter, RIDOH
  • Dr. Eric Suuberg
  • Suuberg lab group
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QuesJons?