Author: Stanley

PFAS Discovery

Reenactment of the 1938 discovery of Teflon. Left to right: Jack Rebok, Robert McHarness, and Roy Plunkett
Reenactment of the 1938 discovery of Teflon. Left to right: Jack Rebok, Robert McHarness, and Roy Plunkett Photo courtesy of Hagley Museum and Library

Per- and polyfluoroalkyl substances (PFAS) are a widely used class of chemicals. You’re probably familiar with some of the popular brand names employing these chemicals such as Teflon, Gortex, and Dockers Stain Defender. As our understanding of PFAS has evolved it is becoming an emergent public health threat. This article is the first in a series serving to provide information on PFAS and it will cover their discovery. Other articles in the series will cover concern, regulation, treatment, environmental fate, contaminated sites, consumer protection, uses and provide sources for further information.

Introduction

Per- and polyfluoroalkyls substances (PFAS) are a family of synthetic substances covering over 4,700 chemicals which have a number of deleterious health effects attributed to them. As of 7 June 2020 California, Connecticut, Colorado, Minnesota, North Carolina, New Hampshire, New Jersey, and Vermont all have state health guidelines for some PFAS. New Jersey’s limits just recently started on 1 June 2020. The US Environmental Protection Agency (EPA) has established a health advisory of 70 parts per trillion of combined PFAS.  While PFAS is not directly regulated under the Toxic Substances Control Act (TSCA) it is monitored under the Significant New Use Rule (SNUR). On 20 February 2020 the EPA proposed a supplemental SNUR for PFAS.

Like most things, an exact beginning is hard to quantify. PFAS’ story could start in a letter dated 26 August 1812 when André-Marie Ampère wrote to Humphry Davy postulating the existence of fluorine, or in 1869 when Dmitri Mendelvee positioned fluorine in the periodic table. An equally rational choice would be 1886 when Henri Moissan first isolated elemental fluorine in France leading to his award of the 1906 Nobel Prize in chemistry. Another serious contender would be Thomas Midgley and A. L. Henne’s 1928 invention of Freon and other chlorofluorocarbons (CFCs) in their Fridgidaire laboratory, which at the time was a General Motor’s subsidiary. I am choosing to start PFAS’ story with Roy Plunkett’s 1938 discovery of Teflon and the birth of fluoropolymers.  

Discovery

On 6 April 1938 at the Chemours Jackson Laboratory in New Jersey Dr. Roy Plunkett discovered polytetrafluoroethylene (PTFE) by accident while researching new CFC refrigerants. While CFCs are now banned for their deleterious atmospheric effects under the Montreal Protocol, at the time they were used to replace ammonia and sulfur dioxide refrigerants which killed dozens of workers annually. PTFE is better known by its brand name: Teflon. Although CFCs are perfluorinated compounds, PTFE was the first discovered chemical in the class of Per- and polyfluoroalkyl substances.

After work on 5 April 1938, Dr. Plunkett and his assistant Jack Rebok reacted tetrafluoroethylene (TFE) with hydrochloric acid then compressed the mixture into metal cylinders and froze it overnight. The next morning on the 6th of April, Jack Rebok placed one of the cylinders onto a balance then opened the stop valve. Only 990 grams of TFE came out of a supposedly 1 kg container. Puzzled by the mass balance, Dr. Plunkett tipped the cylinder over and a white powder fell out. Then Dr. Plunkett stuck a metal wire to try and get more of the substance out. He was unable to get much out that way so eventually Jack Rebok suggested to cut the flask open.

Photo of lab notebook page where Plunkett recorded the discovery of PTFE
Photo of lab notebook page where Plunkett recorded the discovery of PTFE from Kinnane, A. (2002). DuPont: From the banks of the Brandywine to miracles of science.

In Dr. Plunkett’s article The History of Polytetrafluoroethylene: Discovery and Development he wrote:

On the morning of April 6, 1938, Jack Rebok, my assistant, selected one of the TFE (tetrafluoroethylene) cylinders that we had been using the previous day and set up the apparatus ready to go. When he opened the valve — to let the TFE gas flow under its own pressure from the cylinder — nothing happened…We were in a quandary. I couldn’t think of anything else to do under the circumstances, so we unscrewed the valve from the cylinder. By this time it was pretty clear that there wasn’t any gas left. I carefully tipped the cylinder upside down, and out came a whitish powder down onto the lab bench. We scraped around some with the wire inside the cylinder…to get some more of the powder. What I got out that way certainly didn’t add up, so I knew there must be more, inside. Finally…we decided to cut open the cylinder. When we did, we found more of the powder packed onto the bottom and lower sides of the cylinder.

Instead of ignoring the powder Dr. Plunkett started experimenting on it and discovered PTFE is highly resistant to corrosive acids, has excellent performance in extreme temperatures, and does not dissolve in solvents. This along with its slippery nature lead to DuPont sending PTFE to its central research department. However, no real commercially viable use was found for PTFE.

Ironically, World War II saved Teflon from oblivion. On its own PTFE, what Dr. Plunkett discovered, is a relatively useless polymer. It melts at around 327°C (≈620°F) and under that temperature sits in a ball of nonflowing gel. PTFE does not dissolve in anything and does not react with acids, bases, or solvents and at the time cost about $100 per pound (about $1,820 per pound or $4.02 per gram in 2020 dollars) to manufacture.

The Manhattan Project was the US effort to develop the atomic bomb and the savior of PTFE. The Manhattan Project needed corrosion resistant materials to separate U-235 from U-238 using differential diffusion of UF6. After Lieutenant General Leslie Groves heard of PTFE’s inertness, he verified it could separate U-235 from U-238. Then following LTG Groves’ request, the US Patent Office placed PTFE under a “Secrecy Order” and it was referred to only as “K-416.” Following military interest, DuPont patented PTFE in 1941 and registered the trade name Teflon in 1944.  The secrecy order lasted until 1946; by that time the Manhattan Project had paid for a great deal of research that otherwise would not have been carried out on the polymer and its manufacturing cost dropped tremendously.

Dr. Plunkett is also famous for leading DuPont’s team which added tetraethyllead (CH3CH2)4Pb to gasoline (which was phased out under the Clean Air Act) and for significant improvements to freon (a CFC refrigerant).

Brief PFAS Use Examples

The examples of PFAS extend across all facets of human life, from everyday household cookware to aerospace and electronics. PFAS’ widespread use takes advantage of its beneficial properties: chemical resistance, thermal stability, cryogenic properties, low friction coefficients, low surface energies, low dielectric constants, high volume and surface resistivities, and flame resistance. Once it was used to separate U-235 from U-238, the Manhattan Project immediately started finding other uses for PTFE. For example, PTFE was also used in the Manhattan Project in the antenna cap of proximity fuses thanks to its electrical insulating property and invisibility to Doppler radar. Fuel tank coatings used PTFE because of its resistance to low temperatures. After World War II, Teflon was turned to human well-being and started being used in catheters because of its low friction coefficient. PTFE was also used as insulation for wires and cables. It was even used during the Statue of Liberty’s renovations.  PTFE often serves as a precursor for other PFAS chemicals which were ubiquitous until their dangers were realized. PFAS are used in fire fighting foams, ski wax, stain-resistant materials (rugs, clothing, furniture, sprayable stain protectors), cookware, outdoor gear, cosmetics, shaving cream, sunscreen, shampoo, and myriad other applications.

Conclusion

While it may seem easy to villainize Dr. Plunkett for his discovery’s degradation of the environment and damage to human health it is critical to remember Dr. Plunkett in the context of this time. Early refrigerants included sulfur dioxide and ammonia; both regularly poisoned people. His contributions to tetraethyllead boosted octane levels enabling, among other things, advanced plane flight and jets. His work introduced numerous new products and processes which are widely used in medicine, refrigeration, aerosol, electronic, plastics, and aerospace. Several of his innovations are of critical importance to national defense.  There was also less awareness of the dangers of persistent chemicals to humans and the environment.

Further References

The EPA has designated Lahne Mattas-Curry as a point of contact and can be reached at mattas-curry.lahne@epa.gov

For more on the history and discovery of PFAS:

Other articles in the series include PFAS Structure

The EPA’s PFAS website is https://www.epa.gov/pfas

The EPA Long-Chain Perfluoroalkyl Carboxylate and Perfluoroalkyl Sulfonate Chemical Substances; Significant New Use Rule; Supplemental Proposal

PFAS SNUR on regulations.gov

NJ’s new PFAS rule

PFASproject.com – a group of faculty, post-doctoral scholars, graduate students, and undergraduates affiliated with the Social Science Environmental Health Research Institute at Northeastern University operating on an NSF grant

Cross Connection Control and Community Gardens

An Englewood Chicago Community Garden. Photo by Wendell Hutson
Englewood Chicago community gardens photo by Wendell Hutson

It’s not everyday cross-connection control and backflow makes community news. Recently, The Block Club Chicago indirectly wrote an article on cross-connection control and backflow prevention here which can serve to illustrate some interesting points.

The Block Club’s article is on how small community gardens are folding because Chicago recently changed some rules. The rule changes caused an increase in operational and capital expenditure for these gardens.

Since industrialization, communal gardens subdivided into individual plots have been a popular past time that help reconnect urban dwellers with food sources or escape the city for hobby gardening. In Europe these have been around for centuries. These are called “kolonihaver” in Denmark, “Schrebergarten” in Germany, “Volkstuinen” in the Netherlands, and by other names elsewhere. Some of Chicago’s lower income communities use communal gardens for increased food and nutritional security. In Chicago, the communal gardens also help to maintain city owned land that would otherwise be vacant.

Overview:

Chicago recently updated their cross-connection backflow prevention program requirements mandating reduced pressure zone device instead of the previously required atmospheric vacuum breakers. This change had two distinct consequences. The Block Club article focused on one; the dramatic increase in expenses for community gardens potentially causing several to fold. The second point not emphasized in the article was that this change also protects against backpressure instead of just back-siphonage. The existence of the Block Club’s article seems to point to poor understanding on the part of various stakeholders.

Topical Definitions:

A cross-connection is where the potable water system meets contamination which could affect the quality of the water. Various plumbing codes define cross-connections in different ways but they all generally follow the same pattern. The Uniform Plumbing Code of 2006 defines a cross-connection as:

Any physical connection or arrangement between two otherwise separate piping systems, one of which contains potable water and the other either water of unknown or questionable safety or steam, gas or chemical, whereby there exists the possibility for flow from one system to the other, with the direction offlow depending on the pressure differential between the two systems.

The American Water Works Association (AWWA) acknowledges that a cross-connection can occur between the potable water system and an environment as opposed to a piping system.

Backflow is essentially the reversal of the hydraulic gradient causing water to flow into the opposite direction. There are two chief kinds of backflow: back siphonage and backpressure. Back siphonage occurs when the potable water system experiences a pressure drop. This causes it to fall below atmospheric pressure and brings water into the system. An example of back siphonage would be a utility/janitor sink that is filled with a non-potable solution and having a main break or similar event compromise system pressure. Back pressure occurs when downstream pressure exceeds supply pressure causing water to reverse flow. Backpressure requires an external force to push back on the water supply as is the case with elevated piping. The American Water Works Association has provided two helpful diagrams to differentiate these two situations:

An example of back siphonage from AWWA
Back siphonage example from AWWA Manual 14: Backflow Prevention and Cross Connection Control Recommended Practices
An example of back pressure from AWWA
Back pressure example from AWWA Manual 14: Backflow Prevention and Cross Connection Control Recommended Practices

Backflow Prevention Devices/Assemblies are specifically manufactured plumbing designed to prohibit backflow. The term ‘device’ is typically used for non-testable backflow prevention fittings while ‘assembly’ normally refers to testable fittings. The American Society of Sanitary Engineering, the American Water Works Association, and the University of Southern California’s Foundation for Cross-Connection Control and Hydraulic Research are the main certifying agencies. It is important to note that devices and assemblies must be installed along a specific orientation; some are only allowed to be installed vertically, others only horizontally, and some in various orientations. Incorrect instillation can preclude the proper function of the assembly. There are six basic types of backflow prevention assemblies: air gaps, barometric loops, vacuum breakers (both atmospheric and pressure), double check valve assemblies, double check with intermediate atmospheric vent assemblies, and reduced pressure principle devices. The type of assembly used is based upon the degree of hazard posed by the type of cross-connection. Atmospheric vacuum breakers for instance are only effective against back siphonage and cannot prevent backflow from backpressure.

Legislative Framework:

The Safe Drinking Water Act allows the federal government to grant primacy to local authorities for the administration and enforcement of federal drinking water rules and regulations. Agencies that have primacy must have cross-connection control rules. State requirements for cross connection control programs are highly inconsistent, and state oversight is also varied.  States should have a cross connection control program that includes a process for hazard assessment, the selection of appropriate backflow devices, certification and training of backflow device installers, and certification and training of backflow device inspectors.

Discussion and Conclusions:

Recently, Chicago changed requirements for tapping fire hydrants. Previously, atmospheric vacuum breaker devices were required; now reduced pressure zone devices are.

The Block Club article allows some inferences to be made. For instance, the water used in Chicago’s gardens is unmetered and unpaid for through directly tapping fire hydrants. This water would be considered an “apparent loss” as opposed to a “physical loss” on a water audit. The article further goes onto mention that each growing season costs the garden operators about $400. This represents money which could be used to help maintain Chicago’s decaying water infrastructure. Formerly, there was an environmental department in Chicago that helped to offset these costs for low income communities. This department was cut as part of cost conservation measures. This department did not provide some sort of cost accounting metric for Chicago’s Water Utility Board.

It is surprising that Chicago ever allowed atmospheric vacuum breakers to be used for this purpose as areas which could have pesticides or fertilizers applied to it are high risk. This type of situation is one of the most common causes of backflows in the United States. Transient events such as these are notoriously difficult to determine exact societal burdens for. Acute gastrointestinal issues caused by transient events may or may not be widespread enough to be captured. However, even if acutely deleterious health effects are not apparent introduction of organic matter to chlorinated water causes chronically damaging disinfection byproducts and small amounts of pesticides which over time can lead to a dramatic disease burden. It seems that Chicago did not adequately communicate how the backflow device change serves to protect the health of those served by the water system.

However, typical backflow prevention assemblies normally cost around $300-400 for installation and about $60 for annual testing. The cost in Chicago however is $1,700 for installation and $150 for annual testing. 

In addition to benefits in the form of food and nutritional security, communal gardens also represent private citizens taking care of public lands without seeking renumeration from the state for their labor or tools. Free maintenance is a clear benefit for Chicago, although without further detailed cost benefit analysis the cost effectiveness of the strategy cannot be determined. However, the roughly $550 per year ($400 in water costs and $150 for annual testing) seems a reasonable amount for the upgrade and maintenance of communal garden-sized city plots.

Overall, the situation is at best a mixed bag. One of the key issues caused by Chicago’s action is that it removed a key source of food and nutrition from low income communities. An issue unresolved by this change is that Chicago’s water utility was not compensated for the water used. An urgent issue fixed through this change was securing the water quality provided by the utility. While greater stakeholder engagement is unlikely to have resolved these issues it could have helped assuage various stakeholder groups or opened a cost benefit dialogue accounting for the free maintenance the city received for the maintenance of these plots.

Further References:

America’s Water Infrastructure Act of 2018 Risk and Resiliency Requirements

The purpose of this article is to outline America’s Water Infrastructure Act of 2018 (AWIA 2018) Title II Drinking Water System Improvement Section 2013: Community Water System Risk and Resilience. The AWIA 2018 addresses the evaluation and reporting for many facets of infrastructure encompassing various forms of water and energy as well as providing funding. The Act was sponsored by Senator Amy Klobuchar (D-MN) and unanimously passed by the US House of Representatives and US Senate then signed into law by President Trump on October 23, 2018. The focus of this article is Section 2013 Community Water System Risk and Resilience.

Overview

Section 2013 of America’s Water Infrastructure Act of 2018 (AWIA 2018) amended Section 1433 of the Safe Drinking Water Act (SDWA) which added requirements on community water systems that serve 3,300 or more people to complete a risk and resilience assessment then develop an emergency response plan (ERP). Additionally, these must be updated whenever there is a major change in the water system or every five years, whichever is first. The full text of the law may be found here and the Federal Register Notice for New Risk Assessments and Emergency Response Plans for Community Water Systems is available here. Revised Section 1433(a) requires the risk and resiliency assessments, and Revised Section 1433(b) requires the ERPs.

History

In the United States, water system resilience to natural and manmade incidents and emergency response preparedness first became a national priority following the terrorist attacks of September 11th, 2001. Section 401 of the Public Health Security and Bioterrorism Preparedness and Response Act of 2002 (Bioterrorism Act of 2002) amended the Safe Drinking Water Act (SDWA) inserting section 1433-1435. Section 1433 of the SDWA required all community water systems serving a population greater than 3,300 to conduct a water system vulnerability assessment. The assessment was meant to look specifically at terrorism or other intentional acts intended to substantially disrupt the provision of a safe and reliable drinking water supply and develop or revise emergency response plans. The act specifically required the following six areas:

  1. A review of pipes and constructed conveyances
  2. Physical barriers
  3. Water collection, pretreatment, treatment, storage, and distribution facilities
  4. Electronic, computer, or other automated systems which are utilized by the public water system
  5. The use, storage, or handling of various chemicals
  6. The operations and maintenance of the system

New Requirements

AWIA has similar requirements for the risk assessment. The risk assessment shall include an assessment of:

  1. The risk to the system from malevolent acts and natural hazards
  2. The resilience of the pipes and constructed conveyances, physical barriers, source water, water collection and intake, pretreatment, treatment, storage and distribution facilities, electronic, computer, or other automated systems (including the security of such systems) which are utilized by the systems
  3. The monitoring practices of the system
  4. The financial infrastructure of the system
  5. The use, storage, or handling of various chemicals by the system
  6. The operations and maintenance of the system

And may include an evaluation of capital and operational needs for risk and resilience management for the system.

Comparison

The biggest differences between these two laws are the revelation that natural hazards can be as bad as terrorist incidents for an unprepared water systems, an ongoing review/update requirement recognizing the iterative nature of risk, inclusion of the financial infrastructure of the water system, and a copy of the assessment and plan are not required to be forwarded to the United States Environmental Protection Agency (USEPA).

Upcoming Assistance

The law also requires the USEPA to publish Baseline Information on Malevolent Acts Relevant to Community Water Systems. This publication will be available by August 2019 and no water system is able to certify completion of their risk assessment or ERP until this is published because utilities are meant to integrate that framework into their risk assessments. The USEPA administrator is required to consult with “appropriate departments and agencies of the Federal Government and with State and local governments” to provide baseline information on malevolent acts of relevance including any acts which may:

  1. Substantially disrupt the ability of the water system to provide a safe and reliable supply of drinking water
  2. Otherwise present significant public health or economic concerns to the community served by the system

Certification, Requirements, and Deadlines

The USEPA requires each utility to submit certification of the risk and resilience assessment and emergency response plan. Submissions must include: utility name, date, and a statement that the utility has completed, reviewed, or revised the assessment. The USEPA has developed an optional certification template which will be available in August 2019. The risk assessment and ERP may be self-certified by the utility. Certifications maybe submitted by regular mail, email, or an online portal. The online submission portal will provide drinking water systems with a receipt of submittal. The online portal is the favored and recommended method. All certification systems will be available in August 2019. The AWIA 2018 also states that no local, state, or regional government entities must receive copies of this certification.

Regardless, water systems serving greater than 100,000 people must submit the risk assessment by 31 March 2020; water systems serving between 50,000 and 99,999 by 31 December 2020; water systems serving between 3,301 and 49,999 by 30 June 2021.

Similarly, the utility must certify to the USEPA that it has reviewed and, if necessary, revised its ERP. The ERP is required no later than 6 months after the risk assessment. This means that a water utility serving greater than 100,000 people is required to have developed an updated ERP by 30 September 2020, a system serving between 50,000 and 99,999 is required by 30 June 2021, and a system serving 3,301 to 49,999 is required by 30 December 2021.

The ERPs are required to include:

  1. Strategies and resources to improve the resilience of the system, including the physical and cybersecurity of the system
  2. Plans and procedures that can be implemented and identification of equipment that can be utilized in the event of a malevolent or natural hazard that threatens the ability of the community water system to provide safe drinking water
  3. Actions, procedures, and equipment which can obviate or significantly lessen the impact of a malevolent act or natural hazard on the public health and the safety and supply of drinking water provided to communities and individuals, including the development of alternative source water options, relocation of water intakes, and construction of flood protection barriers
  4. Strategies that can be used to aid in the detection of malevolent acts or natural hazards that threaten the security or resilience of the system

The AWIA 2018 does not require the use of any standards, methods, or tools for the risk and resilience assessment or emergency response plan. AWIA 2018 only requires utilities to ensure that all criteria in AWIA Section 2013(a) and (b) are met. The USEPA however, recommends the use of AWWAJ100-10 Risk and Resilience Management of Water and Wastewater System. The USEPA also provides some tools to facilitate sound risk and resilience assessments and ERPs.

Disposition of Bioterrorism Act Assessments

Title IV of the Bioterrorism Act of 2002 required submittal of a written copy of the risk assessment and ERP to be forwarded to the USEPA. The USEPA intends to destroy these records however, under AWIA 2018 section 2013(B)(2) utilities may request their assessments and plans in lieu of destruction by emailing WSD-Outreach@epa.gov on their utility letterhead then in the request include the utility name, address, point of contact, and public water system identification before the date by which the water system is required to certify a risk and resilience assessment to the USEPA under section 1433(A) of the SDWA as amended by section 2013 of the AWIA 2018.

Further Resources

The USEPA Water Security Division can be reached for more help at dwresiliencehelp@epa.gov.

In April 2019, The USEPA Office of Water published a factsheet about the AWIA EPA-817-F-19-004 to help answer some questions about the AWIA requirements. This is available here.

The USEPA is offering in person training on these topics which you can register for here.

Other information on water system resilience is available here.

Finally, Nushat Dyson was listed as a point of contact and can be reached at dyson.nushat@epa.gov or (202) 564-4674.