EMERGING CONTAMINANTS POLY- AND PERFLUOROALKYL SUBSTANCES (PFAS)

Transcription

1 EMERGING CONTAMINANTS POLY- AND PERFLUOROALKYL SUBSTANCES (PFAS) February 22, 2017 Presented by Mark A Travers, P.G. Executive Vice President and Principal Site Solutions

2 WHY THE INTEREST IN PFAS Being found widely distributed in the environment and attracting increasing attention over the past decade Persistent and resistant to degradation Potential human toxicity Wide range of industrial and commercial applications and potential for exposure Non-stick cookware Fabric protectors Paints and coatings Ski wax Microwave popcorn bags and pizza boxes Aqueous Film Forming Foam (AFFF)

3 WHAT ARE PFAS? 1 PFAS is generic term for a large subclass of fluorinated chemicals 2 Used in a wide range of industrial applications, commercial products, and fire fighting foams 3 Unique because of their ability to repel oil, grease and water 4 Exceptionally stable, non-reactive chemicals, resistant to degradation naturally and heat resistant 5 Relatively mobile in the environment, moderately soluble 6 May be subject to long-range transport F F F F F F O F C C C C C C C C OH F F F F F F F F PFOA perfluorooctanoic acid F F F F F F F F F C C C C C C C C SO 3 H F F F F F F F F PFOS perfluorooctanesulfonic acid

4 PFAS: A PERSPECTIVE FROM THE US s Synthetic fluorinated chemicals developed as oil and water repellent 1950s-70s 3M disposed of PFC waste in Oakdale, Woodbury, Cottage Grove and Washington County, Minnesota M stopped production of Scotchgard and ceased PFOS production at Cottage Grove plant 2005 $235Mil lawsuit brought against DuPont over PFC contamination in the Ohio river 2009 EPA established drinking water health advisories of 0.4 ppb for PFOA and 0.2 ppb for PFOS 2016 EPA revises drinking water health advisory to 0.07 ppb for combined PFOA and PFOS 1966 AFFF was patented as a method for extinguishing liquid hydrocarbon fires and implemented by the DoD in s EPA receives information on PFOS and PFOA blood levels in general population 2004 PFCs found to have contaminated drinking water supplies in Minnesota 2006 EPA launches PFOA Stewardship Program 2013 EPA initiates requirement for public drinking water supply monitoring of 6 unregulated perfluorinated compounds 2017 DuPont settles toxic exposure law suit for $671Mil

5 PFAS: A PERSPECTIVE FROM THE US Still considered an Emerging Contaminant Pose a real or perceived threat to human health or to the environment Not currently regulated or have regulations pending New source has been identified or a new exposure pathway to humans has been discovered New detection method or a new water treatment technology has been developed

6 2006 EPA PFOA STEWARDSHIP PROGRAM The last time PFOS manufacture was reported to EPA was 2002 The manufacture and import of PFOA has also been phased out in US as part of the PFOA Stewardship program. Commit to achieve a 95 percent reduction in emissions and product content no later than 2010 PFOA Precursor chemicals Related higher homologues 2014 EPA Progress Report US Operations (all 8 manufacturers reporting) %Reduction, PFOA Emissions: >91% %Reduction, PFOA Product Content: >94% PFAS LEVELS IN THE US POPULATION OVER TIME GEOMETIC MEAN SERUM CONC (UG/L) PFOS PFOA Eliminate by 2015 NHANES SURVEY YEARS

7 CONTINUING CONCERNS Detected Not detected No data From Hu et. al Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. ES&T Letters. July.

8 CONTINUING CONCERNS Detected Not detected No data From Hu et. al Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. ES&T Letters. July.

9 WHAT ARE THE SOURCES OF PFAS? PFAS are man-made chemicals, not naturally occurring PFOA Historical Uses AFFF Food packaging Dyes, polishes, adhesives, lubricants Photolithographic industry Insecticides, herbicides Teflon production PFOS Historical Uses AFFF Food packaging Textile, carpets, furniture, outdoor clothing (e.g., Stainmaster, Scotchguard and Goretex) Oil and gas industry Polishes, ink, paint, varnishes Metal and plastic coatings Coating of photographic films, printing plates Detergents, carpet cleaners Insecticides Cleaning fluids, shampoos, hand creams Hydraulic fluids

10 RELEASE MECHANISMS PRIMARY WIND DIRECTION AIR EMISSIONS MANUFACTURING FACILITY AQUEOUS DISCHARGE RIVER LEAK/SPILL WELL WELL From Davis et al Chemosphere 67:

11 KEY EXPOSURE SCENARIOS Primary human exposure is via drinking water (ingestion) PFAS are readily absorbed after ingestion and accumulate primarily in the serum, kidney and liver. Toxicological studies on animals indicate potential developmental, reproductive and systemic effects.

12 TOXICOLOGY Readily absorbed Not metabolized Distributed predominantly to the liver and blood (serum) Leaves the body through urine and feces Reabsorbed to the body to an extent after excretion into urine and bile Can cross the placenta and be present in breast milk Median elimination half life for exposed community = 840 days (2.3 years)

13 DEVELOPMENT OF REGULATORY STANDARDS Although it is recognized that data from various animal species are not known to apply to people, regulatory policy dictates that data from such studies are to be used for standard setting and other regulatory policies. The only exception is when the scientific evidence is developed to show convincingly that the biological processes by which a particular effect is caused in an animal does not or could not operate in humans.

14 PFOA DRINKING WATER STANDARDS IN THE UNITED STATES

15 PFOA DRINKING WATER STANDARDS IN THE UNITED STATES PFOA USEPA New Jersey Vermont Current d Proposed h Study Lau et al Sibinski 1987 Loveless et al Lau et al a Effect Developmental (reduced ossification, accelerated puberty) Decreased body weight gain, hematological changes Increased liver weight Developmental (reduced ossification, accelerated puberty) Species Mice Rat (female) Mouse (male) Mice Dose or Serum PFOA Value LOAEL: 1 mg/kg/day or 38 mg/l serum modeled LOAEL: 1.6 mg/kg/day or 1800 ppb serum modeled e 4.35 mg/l BMDL 10 LOAEL: 1 mg/kg/day or 38 mg/l serum modeled Human Equivalent Dose b 5.3 x 10-3 mg/kg/day NA NA 5.3 x 10-3 mg/kg/day Reference Dose 2x 10-5 mg/kg/day NA 2 x 10-6 mg/kg/day i 2x 10-5 mg/kg/day Target Human Blood Level NA 18 ppb f 14.5 ng/ml NA Total Uncertainty Factor j 300 Consumption rate L/kg/day c NA 0.03 L/kg/day k L/kg/day l Relative source contr Drinking Water Conc ug/l 0.04 ug/l g ug/l 0.02 ug/l

16 INTERNATIONAL REGULATORY THRESHOLD VALUES

17 TREATMENT OPTIONS Challenges Extremely stable Do not hydrolyze, photolyze, or biodegrade under typical environmental conditions Are extremely persistent in the environment For example the half-life (at 25º C) in water for PFOA and PFOS is > 92 years and > 41 years, respectively High potential to absorb to substrates Migration depends upon groundwater flow and the charge of the substrateexisting treatment processes ineffective / limited Waste disposal costs Unintended (and unknown) end products Currently in use Adsorptive Media GAC proven for water, but expensive and may not be broadly applicable to treat full suite Ion Exchange - expensive Thermal requires high temp, expensive Excavation & Landfill prohibited or require pre-treatment Emerging? Biological not proven Chemical emerging, but efficacy not proven Fixation -

18 TREATMENT OPTIONS DRINKING WATER Granular activated carbon (GAC) is most preferred & implemented technology Other adorptive media available Ion exchange resins or reverse osmosis (RO) can also be utilized Treatment option Activated carbon RECOMMENDATION ON PERFLUORINATED COMPOUND TREATMENT OPTIONS FOR DRINKING WATER. NEW JERSEY DRINKING WATER QUALITY INSTITUTE TREATMENT SUBCOMMITTEE, JUNE 2016 Notes Granulated GAC is the most common treatment method for long-chain PFC removal. Competition for adsorption with other contaminants can reduce effectiveness. Thermal regeneration of GAC is effective. Powdered High concentrations of PAC necessary. PAC may be useful in responding to spills but the required high concentrations may make this an infeasible option. PAC combined with waste residuals may create a challenge for disposal of waste products. Removal rates PFNA PFOA PFOS >90% >90% >90% Membrane filtration Multi-contaminant removal. Rejection rate can be high. Waste/byproducts must be managed. Mineral addition may be necessary. >90% >90% >90% Anion exchange Single-use systems do not produce contaminant-containing brine but required replacement and proper disposal. Regenerable systems produce brine that must be disposed of responsibly; such systems are automated, have small footprints and high regeneration efficiencies. Competition with common ions for binding sites on resins can impact effectiveness. >67% 10-90% >90% Advanced oxidation Low removal rate. Can destroy pollutants to produce less complex compounds. Other organic contaminants will compete for hydroxyl radicals and reduce efficiency. <10% <10% <10-50% Sources: Hohenstein, Gary. Overview of Remediation Technologies. Presentation at Emerging Contaminants Summit. Denver, CO. March NJDEP, Recommendation on Perfluorinated Compound Treatment Options for Drinking Water, New Jersey Drinking Water Quality Institute Treatment Subcommittee, June 2015.

19 TREATMENT OPTIONS EMERGING TECHNOLOGIES Oxidation via conventional methods is difficult due to strength of the C-F bond and may lead to higher PFCA / PFSA levels as a result of precursor breakdown using oxidants Approaches being evaluated include Persulfate under acidic conditions + high temperature Ozonation Activated Persulfate Oxidation of Perfluorooctanoic Acid (PFOA) in Groundwater under Acidic Conditions. P. Yin, et al. 2016

20 REMEDIATION TECHNOLOGY SUMMARY Technology P&T, with GAC P&T, with synthetic resin (ion exchange) Status Soil Media Groundwater In- Situ?? Ex- Situ Treatment Type A A Precursor Concerns Cost Efficiency Other Secondary treatment/disposal required for adsorptive media, not as efficient for PFOA and other PFAS? Media can be regenerated on-site, still in research stage Advanced Chemical Oxidation Sonochemical Decomposition D D? Conditions to destroy PFAS are difficult to apply at full scale for in-situ remediation 28% PFOS decomposition achieved in studies, still in early stages of research Air Separation Filtration, Reverse Osmosis Nanofiltration? S S S?? Secondary treatment/disposal required for separated concentrate Pretreatment required to increase filtration efficiency, still experimental Pretreatment required to increase filtration efficiency, limited in total processing capacity Excavation and Incineration Stabilization D? A? High temperature incinerators required to completely destroy PFOS and PFOA RemBind and matcare are emerging PFAS in-situ treatment options A=Adsorption D=Destructive S=Separation

21 SOME TAKEAWAYS 1 Unique properties stable, mobile, and degradation resistant Found in GW mostly in areas where used in manufacturing or at fire training sites Exposure predominantly via food or in drinking water in areas with impacted drinking water supplies Not metabolized in body, can remain in body for longer periods of time Standards are changing different Agencies making different science-policy choices 6 Proven treatment technologies are limited

22 THANK YOU