Per- and Polyfluoroalkyl Substances (PFAS)
By: Steven Lambert | Oct 11, 2021
Per- and polyfluoroalkyl substances (PFAS) refers to a group of synthetic chemicals. There are over 4,700 compounds in this classification, and they are extensively used in the manufacturing of consumer goods due to their non-stick, water-repellant, fire-retardant, and fat-resistance qualities. Many of these substances are used in firefighting and in industrial settings. There is a list of nineteen groups of products that come in direct contact with the consumer, and it is doubtful that this list is complete. Unfortunately, these substances are entering our drinking water and have far-reaching health implications, including:
- Immune system impacts include reduction of antibody response to infection in general and resistance to the benefits of vaccinations
- Cancer of the liver, kidneys, and testicles
- Decreased fertility and hormonal changes
- Growth and learning delays in children
- Elevated cholesterol levels
The United States Environmental Protection Agency (EPA) has set an advisory limit of 70 parts per trillion for these substances, which is under dispute. Some have challenged this limit as inadequate, calling for lower limits. Researchers from governmental and private entities are working on the implications of the health effects, as well as prevention and treatment options. These chemicals have been detected in 49 states and only in recent years has anyone taken the situation seriously.
PFAS pollution is being studied at airports, military installations, and other places where firefighting foam is used. These sources release large quantities of foam during firefighting and training. Foam with considerable concentrations of PFAS was washed off onto the open ground or down storm drains, introducing the pollutant to both surface and well water supplies. This does not account for other shipping or factory spills that may have occurred. One military installation even distributes bottled water to affected communities in its radius due to water analysis results exceeding the EPA advisory limit. The impact on the water supply in Tucson, AZ, for example, forced the shutdown of a drinking water treatment facility serving over 60,000 people. Since then, Tucson has tried to keep the pollutant level down to 18 parts per trillion.
Treatment options are limited and expensive. The EPA has identified several treatment regimens:
- Granular activated carbon (GAC) filtration in which water passes through granular carbon and the pollutant is adsorbed on to the surface of the granules. Problems occur with the cleaning or disposal of the carbon due to the high concentration of PFAS collection. This or any other treatment method will pose the same problem.
- Powdered activated carbon (PAC) is added to the water and the PFAS and other pollutants are adsorbed on the surface of the carbon particles. Again, disposal of spent carbon will pose its own problems.
- Ion exchange is the use of resin beads that act as magnets. The pollutant sticks to the surface of the resin beads as water is filtered through the exchange bed. How to dispose of spent or regenerated material remains a concern.
- Membrane or nano filtration involves passing water through membranes with extremely small pores. This limits any filterable material from being discharged through the filter effluent. Residual treatment or disposal must be done by regulatory instruction. Consult state or federal regulations, as with the previous options presented.
Both GAC and ion exchange beads can be cleaned or “regenerated.” Hopefully, these problems have been addressed, and it is suggested that the reader consults the EPA’s website.
Treatment, however promising, cannot replace prevention and emergency response. There are engineering controls such as spill containment, collection of used material, and proper destruction of the pollutant. PFAS are called “forever chemicals,” in that environmental degradation of the material does not occur. An industrial process, if it does not already exist, for the separation of these compounds into less harmful constituents, should be developed. Closed loop recycling to make use of the material may be an option.
Spills that make it to the soil should be stopped from running off. Contaminated soil should be excavated and replaced immediately with fresh soil to prevent ground and surface water pollution. The spoiled soil will then need to be stored in a contained area for proper disposal.
While some of this may be viewed as opinion, it is in line with established methods of control for other substances.