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Feeding the Waste Cycle: How PFAS ‘Disposal’ Perpetuates Contamination

Tuesday, August 18, 2020

Current methods of managing waste from toxic “forever chemicals” don’t work – and in fact, perpetuate the cycle of contamination, according to peer-reviewed research by scientists from the Environmental Working Group.

In a study recently published in the journal Chemosphere, EWG scientists concluded that burning, discarding and flushing materials containing the toxic fluorinated chemicals known as PFAS do not effectively contain or destroy them but rather end up just returning either the same chemicals or their byproducts back into the environment. In other words, PFAS “disposal” is really just another step in the contamination cycle.

PFAS are used in hundreds of products, such as food packaging, clothing, carpets and cookware, for their waterproofing or grease-proofing properties. They are called “forever chemicals” because they never break down in the environment, which means they could move through the waste cycle indefinitely. PFAS chemicals suppress the immune system and are associated with cancer, reproductive and developmental harms, and reduced effectiveness of vaccines.

Thousands of U.S. communities with PFAS contamination are urgently looking for treatment options, but every technology currently in use produces PFAS-laden waste. These disposal practices move PFAS among waste management sites and contaminate air, soil and water along the way.

With current disposal options, the concentrated PFAS waste likely returns to the environment, to require costly removal once more. This toxic circle makes it clear that reducing or eliminating the production and discharge of PFAS is the most effective way of tackling the difficult issue of disposal of chemicals that do not break down.

The EWG study examines the state of the science of three standard practices for PFAS waste management – incineration, landfilling and wastewater treatment – and makes recommendations for improved treatment practices and additional research.

Health Effects of PFAS

Hundreds of different PFAS are used today. This table details the health effects associated with 12 of the most-studied members of the chemical family.

Table 1. Harm to Human Health From 12 PFAS Chemicals

Chemical

Harm to the Immune System

Harm to Development and Reproduction

Harm to the Endocrine System

Metabolic Changes

Changes in the Liver

Increased Risk of Cancer

 

Weaker immune response; lower antibody production in response to vaccination; increased allergic response; increased risk of asthma; changes in spleen and thymus

Reduced birth weight; pregnancy-induced hypertension; preeclampsia; reduced fertility; reduced duration of breastfeeding; altered mammary gland development; harm to the male reproductive system

Changes in hormone levels, including thyroid and reproductive hormones; thyroid disease; hormone receptor activation

Increased cholesterol and lipids; weight gain; diabetes

Increased liver weight; changes in liver enzymes

Increased risk of testicular, kidney or breast cancer; increased tumors in laboratory animals; evidence for one or more of the key characteristics of carcinogens

PFOA*#

PFOS*#

PFNA*#

PFHxS*#

PFDA*#

PFDoA#

PFHxA*#

GenX*

PFBS*#

PFBA*#

PFHpA*#

PFUA#

* PFAS chemicals detected by EWG in U.S. public drinking water supplies (https://www.ewg.org/research/national-pfas-testing/)

# PFAS included in ATSDR toxicological profile

■ Strong evidence of health effect documented in people or in laboratory animal studies

● Moderate evidence of health effect documented in people or in laboratory animal studies

▲ Not studied or no reported association in available studies

Sources: The Agency for Toxic Substances and Disease Registry; the National Toxicology Program; Environmental Protection Toxicity Assessments for PFBS and GenX; and other sources from the peer-reviewed scientific literature.

Incineration

The carbon-fluorine bonds in PFAS are among the strongest chemical structures on the planet.1,2 This makes PFAS incredibly difficult to destroy.

Laboratory-scale studies have shown that, when incinerated, PFAS can break down to toxic, volatile chemicals such as carbon tetrafluoride and hexafluoroethane, as well as trifluoroacetic acid and hydrogen fluoride. However, there are no peer-reviewed studies on PFAS emissions in commercial incineration facilities that burn different types of waste.3

Currently published research is not sufficient to address the extent to which PFAS can be completely destroyed and the contaminants that are created in the process. An EPA technical brief on PFAS incineration, published in February 2020, noted that “the effectiveness of incineration to destroy PFAS ... is not well understood.”4

Incomplete destruction of PFAS is dangerous because it can result in the formation of smaller PFAS chemicals and breakdown products.5,6 The incinerators can then emit those undetected PFAS and other toxic chemicals, contaminating air, soil and water in nearby communities.7 Some compounds that could be emitted during PFAS incineration are also potent greenhouse gases.

Research shows that airborne PFAS can travel several miles from facilities emitting PFAS, like incinerators and industrial sites.8 Eventually, airborne PFAS are deposited in soil and water in nearby communities, increasing exposure for people in the area. A group of researchers from Bennington University, in Vermont, found elevated levels of PFAS in soil and water samples taken from neighborhoods near the Norlite incinerator in Cohoes, N.Y.9

PFAS incineration has been happening, either directly, for PFAS-based materials such as firefighting foam, or indirectly, through incineration of waste containing PFAS, such as textiles or biosolids and sewage sludge incineration. The incineration of old stocks of PFAS-based firefighting foam – aqueous film-forming foam, or AFFF – is a large source of highly concentrated PFAS waste and has great potential to harm human health and the environment.10

For more than 50 years, the U.S. military has used firefighting foam made with PFAS. In recent years, the military has moved away from AFFF with eight carbon atoms to newer formulations, made with PFAS of six carbon molecules or fewer, despite evidence that these PFAS pose many of the same health risks.11,12 Military and firefighting departments nationwide store large stockpiles of legacy AFFF, for which there is no obvious, environmentally acceptable solution, either for disposal or destruction.

The military has contracts with incinerators to burn this legacy AFFF, even though the Pentagon acknowledges that the risks of incinerating AFFF are not well understood. For example, in April 2017, the Air Force requested proposals for the study of AFFF disposal because “no satisfactory disposal method” had been identified.13

Several community groups near the incineration facilities authorized to burn AFFF are suing the Department of Defense for its failure to protect them from toxic PFAS emissions.14 The groups, represented by Earthjustice, say the Department of Defense has failed to comply with both the National Environmental Policy Act and the new disposal requirements in the FY2020 National Defense Authorization Act, or NDAA.

In May 2020, the Department of Defense moved to dismiss the case brought by these community groups,15 arguing that it has no obligation to stop incinerating AFFF, because the contracts for incineration were made before the passage of the NDAA.

Recommendations

The fate of PFAS under commercial incinerators’ current operating conditions is largely unknown. This data gap must be addressed, and studies should be conducted on PFAS combustion in various types of incinerator facilities, from those handling municipal solid waste or biosolids to those processing hazardous waste. Research is essential on the optimal temperatures and incinerator residence times for complete PFAS destruction in commercially run incinerators.

Landfills

The use of PFAS-based products and materials produces a large quantity of PFAS-laden waste, and the disposal of this waste can cause further contamination. Municipal solid waste includes a mixture of PFAS-containing consumer items, such as food packaging materials, food wares, stain- and water-resistant upholstery, textiles, clothes and carpets either treated or manufactured with PFAS. PFAS are also present in construction and demolition wastes.

The long-term safety of landfill disposal for PFAS is questionable, as PFAS from discarded products and materials end up in landfill leachate and/or groundwater near the landfill. Some older, inactive landfills may release PFAS from materials and wastes discarded decades ago. There are also concerns about landfill stability, due to the potential for greater precipitation and heavier storms associated with global climate change. PFAS can also volatilize into the air. Although studies of PFAS in air above landfills have been conducted in other countries, this research still needs to be done in the U.S.16

Table 2: Studies of PFAS in Landfill Leachate

Country

Number of Landfills in the Study

Number of PFAS Tested

Total PFAS Concentration Reported for Untreated Landfill Leachate, Rounded

United States

(Solo-Gabriele et al., 2020)17

5

11

2.8–18 µg/L

United States

(Lang et al., 2017)18

18

70

0.3–66 µg/L

Germany

(Busch et al., 2010)19

22

43

0.03–13 µg/L

China (Yan et al., 2015)20

5

14

7.3–292 µg/L

China (Wang et al., 2020)21

3

29

22–39 µg/L

Australia

(Gallen et al., 2017)22

27

9

0.2–46 µg/L

Source: Adapted, with modifications, from Stoiber, T., Evans, S., Naidenko, O.V. 2020. Disposal of products and materials containing per- and polyfluoroalkyl substances (PFAS): A cyclical problem. Chemosphere 260: 127659.

In the U.S., landfill leachate is commonly collected and transferred to wastewater treatment plants, whereby PFAS and other contaminants in the leachate end up in wastewater effluent and in treated sewage sludge, also called biosolids. In turn, sewage sludge from wastewater treatment, if not applied on agricultural fields, is either transferred to landfills or incinerated. PFAS contaminants thus cycle between landfills and wastewater treatment, causing food and water pollution in the process.

Recommendations

The practice of transferring landfill leachate to wastewater treatment facilities does not solve the contamination problem. Capturing, treating and retaining PFAS at the landfill site stops the problem from moving further afield. The same approach should be used for all other liquid sources of PFAS pollution.

Wastewater and Biosolids

Wastewater treatment plants receive PFAS from multiple sources, including:

  • Degraded PFAS-based consumer and industrial products that leach into wastewater
  • Industrial facility discharges
  • Landfill leachate transferred to wastewater treatment plants
  • PFAS ingested and eliminated by humans

Conventional wastewater treatment processes cannot destroy or remove PFAS.23,24 Following wastewater treatment, PFAS end up either in wastewater effluent or in sewage sludge, and therefore wastewater treatment plants are one of the focal points in the environmental cycling of PFAS compounds.25

Table 3. Studies Reporting PFAS Measurements in Wastewater

Country

Number of Wastewater Facilities in the Study

Number of PFAS Tested

Sum of PFAS Concentration in the Influent, Rounded

Sum of PFAS Concentration in the Effluent, Rounded

United States

(Schultz et al., 2006)26

1

15

39-132 ng/L

38–124 ng/L

United States

(Masoner et al., 2020)27

5

73

1030–3360 ng/L

330–2110 ng/L

Sweden (Eriksson et al., 2017)28

3

44

41–97 ng/L

31–78 ng/L

European Union (Loos et al., 2013)29

90

7

Not analyzed

Average: 812 ng/L

Maximum: 50,107 ng/L

China (Zhang et al., 2013)30

28

16

0.04–91 ng/L

0.01–107 ng/L

Australia (Nguyen et al., 2019)31

2

17

31–219 ng/L

Not analyzed

Australia (Coggan et al., 2019)32

19

21

9–412 ng/L

34–517 ng/L

Source: Adapted, with modifications, from Stoiber, T., Evans, S., Naidenko, O.V. 2020. Disposal of products and materials containing per- and polyfluoroalkyl substances (PFAS): A cyclical problem. Chemosphere 260: 127659.

PFAS discharged with wastewater effluent into surface water contaminate drinking water for water systems and communities downstream. PFAS contamination also negatively affects other uses of wastewater effluent, such as irrigation and groundwater aquifer recharge.33 The practice of transferring landfill leachate to wastewater plants contributes to the overall PFAS load in wastewater treatment plants.27,32

Longer-chain PFAS are more likely to concentrate in the sludge, whereas short-chain PFAS are more likely to remain in the effluent.32 A study in Germany reported that about one-tenth of the load of PFOA and about half of PFOS arriving with the influent to the wastewater treatment plant ends up in sludge.34

From wastewater treatment plants, treated sewage sludge is applied to agricultural fields, sent to the landfill or incinerated. Some states now require the testing of biosolids for PFAS prior to land application to avoid contamination of crops or animals. Heat treatment, commonly applied to sewage sludge to inactivate pathogenic organisms, increases measurable PFAS concentrations in biosolids.35

Table 4. Studies Reporting PFAS in Biosolids

Study

Number of PFAS Tested

Sum of PFAS Concentrations, Rounded

Where PFAS Were Measured

United States

Samples from 4 wastewater treatment plants

(Kim Lazcano et al., 2019)35

17

18–49 ng/g

Sewage sludge, prior to treatment

8–123 ng/g

Biosolids, after treatment (heat, composting, blending, hydrolysis)

United States

Samples from 1 wastewater treatment plant

(Armstrong et al. 2016)36

12

98 ng/g*

Limed biosolids, dry weight

2–601 ng/g**

Limed biosolids, range of individual PFAS detections, dry weight

United States

Samples from a nationwide sewage sludge inventory

(Venkatesan and Halden, 2013)37

13

539 ng/g*

Sewage sludge, dry weight (air dried prior to extraction)

1.2–618 ng/g**

Sewage sludge, range of individual PFAS detections, dry weight (air dried prior to extraction)

United States

Samples from 2 different sites

(Yoo et al., 2009)38

10

98–682 ng/g

Sewage sludge, dry weight

United States

Samples from 1 wastewater treatment plant

(Schultz et al., 2006)26

15

120–488 ng/g***

Sewage sludge (primary, thickened, or activated)

Canada

Samples from 20 wastewater treatment plants

(Letcher et al. 2020)39

22

5–93 ng/g

Biosolids, dry weight (air dried prior to extraction)

Australia

Samples from 12 wastewater treatment plants

(Sleep & Juhasz, 2020)40

28

5–145 ng/g

Biosolids (air dried)

Australia

Samples from 14 wastewater treatment plants

(Gallen et al., 2018)41

9

5–150 ng/g

Biosolids

Spain

Samples from 16 wastewater treatment plants

(Navarro et al. 2016)42

20

Up to 119 ng/g

Municipal solid waste compost or wastewater treatment plant biosolids, dry weight

China

Samples from 12 wastewater treatment plants

(Chen et al. 2012)24

2

PFOS: 0.5–20 ng/g

PFOA: 0.5–158 ng/g

Sewage sludge

* Average total concentration of PFAS.

** Range of detections for individual compounds detected in biosolids.

*** Sum of averages for individual PFAS detected primary, thickened, or activated sludge samples.

Source: EWG analysis of data from the peer-reviewed scientific literature.

Measuring PFAS concentrations in biosolids prior to field application is crucial, because PFAS are taken up by crops and can end up in food. In addition to PFAS from biosolids, agricultural crops and produce can become polluted by PFAS-contaminated water used for irrigation.43

PFAS uptake and accumulation in edible plants depends on the concentration of PFAS in soil, the amount of organic carbon in soil, the length of PFAS and the type of plants grown.44,45 A 2013 study conducted by scientists from the Colorado School of Mines reported that two PFAS chemicals, 4-carbon perfluorobutanoic acid, or PFBA, and 5-carbon perfluoropentanoic acid, or PFPeA, accumulated in lettuce and tomatoes grown in soil where biosolids were applied.46 Shorter-chain PFAS, which have four to six fluorinated carbons, tend to transfer into the leafy parts of plants, as well as into fruits,47 whereas longer-chain PFAS accumulate in the roots.48

PFAS contamination of produce and other food items poses a public health risk that must be addressed. There are no federal standards, guidelines, or health benchmarks for PFAS in biosolids. In the absence of national requirements, states are starting to develop their own guidelines to address this source of PFAS contamination. The state of Maine now requires that biosolids be tested prior to field application and has set screening levels of 2.5 nanogram per gram, or ng/g, for PFOA; 5.2 ng/g for PFOS; and 1900 ng/g for PFBA.49 New Hampshire is in the process of developing screening standards for PFAS in biosolids,50 and Massachusetts requires testing biosolids for PFAS.51

Recommendations

  • Monitoring PFAS at all wastewater treatment facilities and making those data publicly available.
  • Monitoring PFAS in treated sewage sludge prior to any agricultural application and making those data publicly available.
  • Developing human health-based benchmarks for PFAS in biosolids used for application on agricultural fields.
  • Additional research on advanced PFAS destruction and remediation technologies, specifically for PFAS in sewage sludge and wastewater effluent.

References

1 Kwiatkowski, C.F., Andrews, D.Q., Birnbaum, L.S., Bruton, T.A., DeWitt, J.C., Knappe, D.R.U., Maffini, M.V., Miller, M.F., Pelch, K.E., Reade, A., Soehl, A., Trier, X., Venier, M., Wagner, C.C., Wang, Z., and Blum, A. (2020). Scientific Basis for Managing PFAS as a Chemical Class. Environmental Science & Technology Letters. https://doi.org/10.1021/acs.estlett.0c00255

2 Cousins, I.T., Goldenman, G., Herzke, D., Lohmann, R., Miller, M., Ng, C.A., Patton, S., Scheringer, M., Trier, X., Vierke, L., Wang, Z., and DeWitt, J. C. (2019). The concept of essential use for determining when uses of PFASs can be phased out Environmental Science: Processes & Impacts, 21(11), 1803-1815. https://doi.org/10.1039/C9EM00163H

3 Reviewed in Stoiber, T., Evans, S., and Naidenko, O.V. (2020). Disposal of products and materials containing per- and polyfluoroalkyl substances (PFAS): A cyclical problem, Chemosphere. https://doi.org/10.1016/j.chemosphere.2020.127659

4 United States Environmental Protection Agency. February 2020. Per- and Polyfluoroalkyl Substances (PFAS): Incineration to Manage PFAS Waste Streams. Technical BRIEF: Innovative Research for a Sustainable Future, Issue. https://www.epa.gov/sites/production/files/2019-09/documents/technical_brief_pfas_incineration_ioaa_approved_final_july_2019.pdf

5 California Department of Toxic Substances Control. 2019. Product - Chemical Profile for Carpets and Rugs Containing Perfluoroalkyl or Polyfluoroalkyl Substances. https://dtsc.ca.gov/wp-content/uploads/sites/31/2020/02/Final_Product-Chemical_Profile_Carpets_Rugs_PFASs_a.pdf

6 Feng, M., Qu, R., Wei, Z., Wang, L., Sun, P., and Wang, Z. (2015). Characterization of the thermolysis products of Nafion membrane: A potential source of perfluorinated compounds in the environment. Sci Rep, 5, 9859. https://doi.org/10.1038/srep09859

7 Lerner, S. (2020). Toxic PFAS Fallout Found Near Incinerator in Upstate New York. https://theintercept.com/2020/04/28/toxic-pfas-afff-upstate-new-york/

8 Galloway, J.E., Moreno, A.V.P., Lindstrom, A.B., Strynar, M.J., Newton, S., May, A.A., and Weavers, L.K. (2020). Evidence of Air Dispersion: HFPO–DA and PFOA in Ohio and West Virginia Surface Water and Soil near a Fluoropolymer Production Facility. Environmental Science & Technology, 54(12), 7175-7184. https://doi.org/10.1021/acs.est.9b07384

9 Therrien, J. April 2020. Bennington College team finds elevated levels of PFAS around NY plant. https://www.benningtonbanner.com/stories/bennington-college-teamfinds-elevated-levelsof-pfas-around-ny-plant,603396

10 Hogue, C. February 2020. Groups sue US military to stop PFAS incineration. Chemical & Engineering News. https://cen.acs.org/environment/persistent-pollutants/Groups-sue-US-military-stop/98/web/2020/02

11 Hogue, C. August 2019. Short-chain and long-chain PFAS show similar toxicity, US National Toxicology Program says. https://cen.acs.org/environment/persistent-pollutants/Short-chain-long-chain-PFAS/97/i33

12 Lerner, S. February 2018. The U.S. Military is Spending Millions to Replace Toxic Firefighting Foam with Toxic Firefighting Foam. https://theintercept.com/2018/02/10/firefighting-foam-afff-pfos-pfoa-epa/

13 The Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) program. 2017. Funding Topic Details: AFFF Disposal. https://www.sbir.gov/sbirsearch/detail/1254657

14 Earthjustice. February 2020. Department of Defense Illegally Burning Stockpiles of Toxic “Forever Chemicals”. https://earthjustice.org/news/press/2020/department-of-defense-illegally-burning-stockpiles-of-toxic-forever-chemicals

15 Inside EPA. May 2020. DOD fights suit seeking to block PFAS incineration. https://insideepa.com/daily-feed/dod-fights-suit-seeking-block-pfas-incineration?s=em1

16 Barlaz, M.A., Field, J., Staci, S. Characterization and Quantification of per- and polyfluoroalkyl substances in landfill gas and estimate of emissions from U.S. Landfills. EPA Grant Number: RD839600. https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/10990

17 Solo-Gabriele, H.M., Jones, A.S., Lindstrom, A.B., and Lang, J.R. (2020). Waste type, incineration, and aeration are associated with per- and polyfluoroalkyl levels in landfill leachates. Waste

Management, 107, 191-200. https://doi.org/10.1016/j.wasman.2020.03.034. This study sampled leachate from construction and demolition (C&D), municipal solid waste (MSW), combined C&D and MSW, and combined MSW and waste incineration ash landfills.

18 Lang, J.R., Allred, B.M., Field, J.A., Levis, J.W., and Barlaz, M.A. (2017). National Estimate of Per and Polyfluoroalkyl Substance (PFAS) Release to U.S. Municipal Landfill Leachate. Environ Sci Technol, 51(4), 2197-2205. https://doi.org/10.1021/acs.est.6b05005

19 Busch, J., Ahrens, L., Sturm, R., and Ebinghaus, R. (2010). Polyfluoroalkyl compounds in landfill leachates. Environmental Pollution 158, 1467-1471. https://doi.org/10.1016/j.envpol.2009.12.031

20 Yan, H., Cousins, I.T., Zhang, C., and Zhou, Q. (2015). Perfluoroalkyl acids in municipal landfill leachates from China: Occurrence, fate during leachate treatment and potential impact on groundwater. Science of The Total Environment, 524-525, 23-31. https://doi.org/https://doi.org/10.1016/j.scitotenv.2015.03.111

21 Wang, B., Yao, Y., Chen, H., Chang, S., Tian, Y., and Sun, H. (2020). Per- and polyfluoroalkyl substances and the contribution of unknown precursors and short-chain (C2-C3) perfluoroalkyl carboxylic acids at solid waste disposal facilities. Sci Total Environ, 705, 135832. https://doi.org/10.1016/j.scitotenv.2019.135832. This study also reported PFAS levels in leachate from two municipal solid waste transfer stations and two incinerators.

22 Gallen, C., Drage, D., Eaglesham, G., Grant, S., Bowman, M., and Mueller, J. F. (2017). Australia-wide assessment of perfluoroalkyl substances (PFASs) in landfill leachates. J Hazard Mater, 331, 132-141. https://doi.org/10.1016/j.jhazmat.2017.02.006

23 Arvaniti, O.S., and Stasinakis, A.S. (2015). Review on the occurrence, fate and removal of perfluorinated compounds during wastewater treatment. Science of The Total Environment, 524-525, 81-92. https://doi.org/10.1016/j.scitotenv.2015.04.023

24 Chen, S., Zhou, Y., Meng, J., and Wang, T. (2018). Seasonal and annual variations in removal efficiency of perfluoroalkyl substances by different wastewater treatment processes. Environ Pollut, 242(Pt B), 2059-2067. https://doi.org/10.1016/j.envpol.2018.06.078

25 Hamid H and Li LY. (2016). Role of wastewater treatment plant in environmental cycling of poly- and perfluoroalkyl substances. Ecocycles 2(2): 43-53. https://doi.org/10.19040/ecocycles.v2i2.62

26 Schultz, M.M., Higgens, C.P., Huset, C.A., Luthy, R.G., Barofsky, D.F., and Field, J.A. (2006). Fluorochemical mass flows in a municipal wastewater treatment facility. Environ Sci Technol 40(23): 7350-7357. https://doi.org/10.1021/es061025m

27 Masoner, J.R., Kolpin, D.W., Cozzarelli, I.M., Smalling, K.L., Bolyard, S.C., Field, J.A., et al. (2020). Landfill leachate contributes per-/poly-fluoroalkyl substances (PFAS) and pharmaceuticals to municipal wastewater. Environmental Science: Water Research & Technology. http://dx.doi.org/10.1039/D0EW00045K

28 Eriksson, U., Haglund, P., Karrman, A. (2017). Contribution of precursor compounds to the release of per- and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs). J Environ Sci (China) 61: 80-90. https://doi.org/10.1016/j.jes.2017.05.004

29 Loos, R., Carvalho, R., Antonio, D.C., Comero, S., Locoro, G., Tavazzi, S., et al. (2013). EU-wide monitoring survey on emerging polar organic contaminants in wastewater treatment plant effluents. Water Research 47(17): 6475-6487. https://doi.org/10.1016/j.watres.2013.08.024

30 Zhang, W., Zhang, Y., Taniyasu, S., Yeung, L.W., Lam, P. K., Wang, J. et al. (2013). Distribution and fate of perfluoroalkyl substances in municipal wastewater treatment plants in economically developed areas of China. Environ Pollut 176: 10-17. https://doi.org/10.1016/j.envpol.2012.12.019

31 Nguyen, H.T., Kaserzon, S. L., Thai, P.K., Vijayasarathy, S., Braunig, J., Crosbie, N.D., et al. (2019). Temporal trends of per- and polyfluoroalkyl substances (PFAS) in the influent of two of the largest wastewater treatment plants in Australia. Emerging Contaminants 5: 211-218. https://doi.org/10.1016/j.emcon.2019.05.006

32 Coggan, T.L., Moodie, D., Kolobaric, A., Szabo, D., Shimeta, J., Crosbie, N.D., Lee, E., Fernandes, M., and Clarke, B. O. (2019). An investigation into per- and polyfluoroalkyl substances (PFAS) in nineteen Australian wastewater treatment plants (WWTPs). Heliyon, 5(8), e02316. https://doi.org/10.1016/j.heliyon.2019.e02316

33 Page, D., Vanderzalm, J., Kumar, A., Cheng, K.Y., Kaksonen, A.H., and Simpson, S. (2019). Risks of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) for Sustainable Water Recycling via Aquifers. Water, 11(8), 1737. https://doi.org/10.3390/w11081737

34 Becker, A.M., Gerstmann, S., and Frank, H. (2008). Perfluorooctane surfactants in waste waters, the major source of river pollution. Chemosphere, 72(1), 115-121. https://doi.org/10.1016/j.chemosphere.2008.01.009

35 Kim Lazcano, R., de Perre, C., Mashtare, M.L, and Lee, L.S. (2019)."Per- and polyfluoroalkyl substances in commercially available biosolid-based products: The effect of treatment processes. Water Environ Res 91(12): 1669-1677. https://doi.org/10.1002/wer.1174

36 Armstrong, D. L., Lozano, N., Rice, C.P., Ramirez, M., and Torrents, A. (2016). Temporal trends of perfluoroalkyl substances in limed biosolids from a large municipal water resource recovery facility. Journal of Environmental Management 165: 88-95. https://doi.org/10.1016/j.jenvman.2015.09.023

37 Venkatesan, A. K. and R. U. Halden (2013). National inventory of perfluoroalkyl substances in archived U.S. biosolids from the 2001 EPA National Sewage Sludge Survey. Journal of Hazardous Materials 252-253: 413-418. https://doi.org/10.1016/j.jhazmat.2013.03.016.

38 Yoo, H., Washington, J.W., Jenkins, T.M., and Laurence Libelo, E. (2009). Analysis of perfluorinated chemicals in sludge: Method development and initial results. Journal of Chromatography A 1216(45): 7831-7839. https://doi.org/10.1016/j.chroma.2009.09.051

39 Letcher, R. J., Chu, S., and Smyth, S.A. (2020). Side-chain fluorinated polymer surfactants in biosolids from wastewater treatment plants. J Hazard Mater 388: 122044. https://doi.org/10.1016/j.jhazmat.2020.122044

40 Sleep, J.A. and Juhasz A.L. (2020). Perfluoroalkyl, fluorotelomer sulfonate, and perfluorooctane sulfonamide contamination in biosolids: Composition, co-contamination and re-use implications. Environmental Pollution. In Press. https://www.sciencedirect.com/science/article/abs/pii/S0269749120324003

41 Gallen, C., Eaglesham, G., Drage, D., Nguyen, T. H., and Mueller, J.F. (2018). A mass estimate of perfluoroalkyl substance (PFAS) release from Australian wastewater treatment plants. Chemosphere 208: 975-983. https://doi.org/10.1016/j.chemosphere.2018.06.024

42 Navarro, I., de la Torre, A., Sanz, P., Pro, J., Carbonell, G., and Martinez, M. (2016). Bioaccumulation of emerging organic compounds (perfluoroalkyl substances and halogenated flame retardants) by earthworm in biosolid amended soils. Environmental Research 149: 32-39. https://doi.org/10.1016/j.envres.2016.05.004

43 Scher, D.P., Kelly, J.E., Huset, C.A., Barry, K.M., Hoffbeck, R.W., Yingling, V.L., and Messing, R.B. (2018). Occurrence of perfluoroalkyl substances (PFAS) in garden produce at homes with a history of PFAS-contaminated drinking water. Chemosphere 196: 548-555. https://doi.org/10.1016/j.chemosphere.2017.12.179

44 Ghisi, R., Vamerali, T., and Manzetti, S. (2019). Accumulation of perfluorinated alkyl substances (PFAS) in agricultural plants: A review. Environ Res, 169, 326-341. https://doi.org/10.1016/j.envres.2018.10.023

45 Lechner, M. and H. Knapp (2011). Carryover of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) from Soil to Plant and Distribution to the Different Plant Compartments Studied in Cultures of Carrots (Daucus carota ssp. Sativus), Potatoes (Solanum tuberosum), and Cucumbers (Cucumis Sativus). Journal of Agricultural and Food Chemistry 59(20): 11011-11018. https://doi.org/10.1021/jf201355y

46 Blaine, A.C., Rich, C.D., Hundal, L.S., Lau, C., Mills, M.A., Harris, K.M., Higgins, C.P. (2013). Uptake of perfluoroalkyl acids into edible crops via land applied biosolids: field and greenhouse studies. Environ. Sci. Technol. 47 (24), 14062-14069. https://doi.org/10.1021/es403094q

47 Blaine, A.C., Rich, C.D., Hundal, L. S., Lau, C., Mills, M.A., Harris, K. M., and Higgens, C.P. (2013). Uptake of Perfluoroalkyl Acids into Edible Crops via Land Applied Biosolids: Field and Greenhouse Studies. Environmental Science & Technology 47(24): 14062-14069.

48 Blaine, A.C., Rich, C.D., Sedlacko, E.M., Hundal, L.S., Kumar, K., Lau, C., et al., (2014). Perfluoroalkyl acid distribution in various plant compartments of edible crops grown in biosolids-amended soils. Environ. Sci. Technol. 48 (14), 7858-7865.

49 Maine Department of Environmental Protection. (2019). Memorandum - Requirement to analyze for PFAS compounds. https://www1.maine.gov/dep/spills/topics/pfas/03222019_Sludge_Memorandum.pdf

50 New Hampshire Department of Environmental Services. 2019. Interim best practices for emerging contaminants in certified biosolids. https://www.des.nh.gov/organization/commissioner/pip/factsheets/wwt/documents/web-29.pdf

51 Massachusetts Department of Environmental Protection. PFAS in Wastewater. https://www.mass.gov/info-details/per-and-polyfluoroalkyl-substances-pfas

 

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