Why Doesn’t Melted Cheese Stick to a Food Wrapper?
July 28, 2020
By Dennis Schucker, Ph.D., P.G.
Senior Geologist and Project Manager
This article was originally published in Currents, POWER’s quarterly Environmental newsletter.
The answer can be found in an alphabet soup of acronyms—PFOS, PFOA, PFAAs, PFNA, PFBS—just some of the thousands of per- and polyfluoroalkyl substances commonly referred to as PFAS.
The properties of PFAS include thermal and chemical stability with a strong ability to repel grease, oils and water (think Teflon, Scotchgard and GORE-TEX).
These unique properties make PFAS ideal for developing useful consumer products such as grease-resistant paper used to manufacture food wrappers and microwave popcorn bags. Other items include stain-resistant clothing and carpets, water repellant boots, nonstick frying pans, as well as cleaning and personal care products like dental floss and shampoo.
On a more industrial scale, PFAS have been used at metal-plating facilities, electronic manufacturing facilities, oil recovery operations and, of particular concern, in aqueous film forming foam (AFFF), which is also known as firefighting foam.
AFFF has been used extensively at military bases, airports, oil refineries, chemical manufacturing plants and firefighting training areas.
These chemicals have been used in consumer products and industrial applications since the 1940s, but only recently garnered national interest when PFAS compounds were detected in drinking water supplies throughout the country.
That’s why, even if your business doesn’t manufacture anything or use firefighting foam, you may still need to be concerned with PFAS.
The Effects of PFAS
The potential toxicity and human health effects of PFAS are not completely understood. Findings from human epidemiology studies suggest that increased cholesterol levels, low infant birth weights, immune system issues, cancer and other ailments may be associated with exposure to some PFAS chemicals.
However, potential health effects of one PFAS chemical may be very different from another PFAS chemical. Health effects appear to be a function of the specific PFAS chemical’s composition, and studies show that long-chain PFAS (containing six or more carbon atoms) are more persistent and bioaccumulative (i.e., becomes concentrated inside the body) than shorter-chain PFAS.
For this reason, many long-chain PFAS compounds have been replaced with shorter-chain compounds in manufacturing. This is the case for two of the best-known and arguably most-studied PFAS compounds—perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).
Although many manufacturers have switched from PFOA and PFOS to newer, shorter-chain PFAS, testing methods and toxicity studies are not available for many of these replacement compounds. Their potential presence in the environment and the potential human health effects are unknown.
The Scope of the PFAS Problem
Many questions still exist concerning the magnitude and extent of PFAS in the environment. We really don’t know if PFAS chemicals are everywhere, as recent media coverage may suggest, but it is known that the presence of PFAS in the environment extends beyond manufacturing facilities and other industrial applications that use PFAS and firefighting foam.
Furthermore, some PFAS chemicals are very slow to degrade in nature and the term “forever chemicals” has been coined to describe the presentient nature of these compounds.
Landfill leachate and wastewater treatment plants can be another source of PFAS releases to the environment. Consider the PFAS-coated popcorn bags, fast food wrappers, old carpet and clothing that eventually end up in sanitary landfills or construction and demolition debris landfills.
How many PFAS-containing consumer products and building materials are disposed of in these landfills? How much PFAS will leach from these discarded materials and enter the groundwater? To date, only limited studies have been conducted to investigate these issues.
For a municipal sanitary sewer plant, PFAS enters the plant with the wastewater, but where does it go? PFAS-containing water may be discharged from the plant following treatment; however, PFAS have been detected in biosolids generated from wastewater treatment. These PFAS-containing biosolids are often applied to agricultural land where the chemicals can leach into groundwater.
Long-term application of biosolids in areas containing drinking water supply wells may have the potential to significantly impact drinking water. PFAS may leach from the applied biosolids and enter surface water. Additionally, plants growing in soil where these biosolids have been applied may uptake the PFAS and be directly ingested by humans or livestock.
PFAS bioaccumulates in animals and humans and has been detected in dairy cows and milk products. In fact, long-term studies by the U.S. Agency for Toxic Substances and Disease Registry indicate that most people in the U.S. have been exposed to PFAS and have some level of PFAS compounds in their blood.
Regulations and Guidance: An Ever-Changing Environment
Because of the apparent widespread presence of PFAS in the environment, and the possible health effects, guidance and regulation at both the federal and state level is rapidly evolving.
The U.S. Environmental Protection Agency (EPA) issued a Lifetime Drinking Water Health Advisory of 70 parts per trillion (ppt) and published a screening level of 40 ppt in groundwater for federal clean-up programs.
While EPA continues the regulatory evaluation of PFAS in drinking water, many states have developed more conservative drinking water target levels ranging as low as 10 ppt to 20 ppt. This regulatory patchwork is expected to remain for the foreseeable future.
Although the process of evaluating the science and risk concerning PFAS chemicals will require significant time and effort, and “final” actions for some issues may require years, regulatory drivers are moving forward and PFAS regulation will affect many areas and business practices.
For example, EPA notified Toxic Release Inventory reporters that facilities must begin tracking and collecting data on a list of 172 PFAS chemicals during 2020.
Several states have added specific language to their National Pollutant Discharge Elimination System (NPDES) permitting requirements to address PFAS. Should the regulatory changes concerning PFAS reach the federal or state level, it could affect construction and industrial NPDES permits as well as municipal separate storm sewer systems.
Earlier this year, a major piece of legislation, House Bill 535, was passed by the U.S. House of Representatives. Although now stalled in the Senate, the provisions of this bill touch on many environmental issues centered around PFAS.
These compounds are currently not considered hazardous substances under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA); however, if this bill becomes law, PFOA and PFOS would be designated as hazardous substances.
Designation of these chemicals as CERCLA hazardous substances would affect due diligence investigations conducted under the ASTM standards for property transactions, resulting in potential CERCLA liability and other regulatory issues.
Staying in Compliance
PFAS regulation is a complex and ever-evolving area. EPA continues to implement their PFAS Action Plan and individual states continue to develop unique target levels and guidance. It is prudent to continually monitor the regulatory updates at both the federal and state levels to understand how PFAS regulations may affect your industry and ensure continuing compliance with appropriate laws.
So, now you know why melted cheese doesn’t stick to a food wrapper, and just how sticky the subject of PFAS can be.
About the Author:
Dr. Schucker is a professional geologist and a veteran environmental scientist with a formidable background as an environmental consultant and an academic. His technical responsibilities include management and implementation of geologic and hydrogeologic investigations, regulatory review, environmental assessments, evaluation of groundwater flow and contaminant fate and transport, and preparation of risk assessments including evaluation of migration of volatiles to indoor air. Questions for Dennis? Send him an email at firstname.lastname@example.org.