MSU Extension PFAS Contamination in Agriculture

A group of chemicals used in common household products have received increased scrutiny due to environmental concerns.

The chemicals, synthetic perfluorinated chemicals (PFCs) or more specifically per- and polyfluoroalkyl substances (PFAS), have been widely used in both industrial and consumer products to make those products waterproof, stain and grease resistant.  Common products that contain these chemicals include stain-resistant fabrics and carpets, water and oil repellents, foams used in fighting fires, metal spray plating and some types of nonstick cookware. Other products that have been manufactured with forms of PFAS include food packaging paper and cardboard materials, insecticides, paint and plumbing tape.

PFAS chemicals have been used since the 1950s, but has received increased attention in recent years as the environmental footprint gets larger and environmental impact becomes clearer. Several authors have noted global widespread occurrence of PFAS in both wildlife and humans (Giesy and Kannan 2001; Hansen et al. 2001). Two well-studied forms of PFAS are PFOS (perfluorooctane sulfonate) and PFOA (perfluorooctanoate). They are a concern because of the potential health impacts associated with them.

While some of the PFAS chemicals such as PFOA and PFOS were voluntarily phased out of production between 2000 and 2002 in the U.S. and 2006 in other countries, there are thousands of PFAS chemicals still being produced globally (Wang et al. 2017; EPA 2017b). More so, PFAS chemicals still exist in the environment because they are not easily broken down or degraded. They are toxic, persistent (stable) and can bioaccumulate in organisms.

PFAS contamination is often found near sites where it was produced or used by industries and on military bases. PFAS contaminants are water-soluble and easily infiltrate the soil into groundwater (ATSDR 2017) and find their way into adjacent waters.

PFAS chemicals can be ingested by drinking contaminated water, eating contaminated fish or using some consumer products that may still contain the chemical. According to the Agency for Toxic Substances and Disease Registry (ATSDR 2017), PFAS are not readily absorbed through skin and are considered a minor exposure pathway when showering or bathing in PFAS-contaminated water.

When humans and other animals consume water or food containing PFAS, these chemicals can remain in the body for many years after exposure (Bruton and Blum 2017). The ATSDR has reviewed multiple studies and identified possible impacts from exposure to PFAS in water and food, including effects on growth, developmental effects to fetuses, interferences with hormones, increases in cholesterol, immune system effects and an increased risk of liver, kidney and testicular cancer. In animals, potential health effects may include renal and liver toxicity cancer, immune suppression, reproductive and developmental effects and mortality and delayed development of offspring (Bruton and Blum 2017). However, no one can say with certainty that exposure to PFAS chemicals will result in these health effects.

Levels of exposure

The U.S. EPA has set a lifetime health advisory limit (LHAL) for PFOA and PFOS combined at 70 parts per trillion (ppt) (EPA 2017a). However, some studies have suggested even lower levels for each of these chemicals (Grandjean 2015), and some state health departments, such as Vermont and Minnesota, have established lower health advisory and guidance values. A nationwide survey of larger public water supplies (PWS) found that EPA’s lifetime health advisory (70 ppt) for PFOS and PFOA was exceeded in 66 PWS serving 6 million U.S. residents (Hu et al. 2016). 

The LHAL is the level in drinking water below which no harm to human health is expected even after chronic exposure. Advisory limits do not exist for other PFAS chemicals. Michigan recently adopted the same 70 ppt limit for PFOA and PFOS in drinking water. Because these chemicals can bioaccumulate in aquatic ecosystems resulting in higher levels in fish tissue, the health advisory for surface waters is 11 to 12 ppt.

PFAS chemicals have been identified and confirmed in 15 communities at 30 sites in Michigan. A complete list of these PFAS sites and accompanying map can be found at Michigan.gov.

Michigan Response Team

In November 2017, an executive directive was issued by Gov. Rick Snyder to establish a comprehensive approach to dealing with PFAS contamination across the state. The directive established the Michigan PFAS Action Response Team (MPART). The team includes representatives from 10 state agencies and has been tasked with providing a coordinated and comprehensive response to address sites across Michigan that have been contaminated by PFAS. Working with local, state and national partners, the group is focusing on areas impacted by PFAS, communications and mitigation activities. The directive can be viewed at Michigan.gov.

State of Michigan laboratories do not currently have the capability to test for PFAS but are hoping to do so in mid-to-late 2018. Tests for PFAS contaminants in drinking water can cost hundreds of dollars per sample (EPA 2017a). If you have been notified by your local health department that PFAS chemicals have been detected in your water supply, you may be given access to an alternative water supply or in-home filtration at no cost.

Treating your water

For residents treating their own water, there are several ways to reduce some of the PFAS compounds. Drinking water treatment units that are able to reduce PFOS and PFOA to below 70 ppt and that have been certified by NSF International, include point-of-use carbon-based systems, such as activated carbon, reverse osmosis and nanofiltration systems. Conventional treatments utilizing coagulation, flocculation, sedimentation and filtration will not remove PFAS. Oxidants and disinfectants have also been shown to be ineffective in controlling these chemicals in drinking water (NSF International 2017).

The Michigan Department of Environmental Quality (MDEQ) has developed a fact sheet that addresses point of use treatment. A PFAS website has also been developed by the State of Michigan to address questions.

This article was reviewed by

Dr. Courtney Carignan - Department of Food Science and Human Nutrition

Steven Hussey and Megan Sprague - Michigan Department of Agriculture and Rural Development. 

CITED REFERENCES:

ATSDR - Agency for Toxic Substances and Disease Control. 2017. Per- and Polyfluoroalkyl Substances (PFAS) and Your Health. Agency for Toxic Substances and Disease Registry (ATSDR). Online at: https://www.atsdr.cdc.gov/pfas/index.html

Bruton, Thomas A., and Arlene Blum. 2017. Proposal for coordinated health research in PFAS-contaminated communities in the United States. Environmental Health 16:120. Online at: https://doi-org.proxy2.cl.msu.edu/10.1186/s12940-017-0321-6

EPA (Environmental Protection Agency). 2017a. Drinking water health advisories for PFOA and PFOS Online at: https://www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos

EPA. 2017b. Basic Information on PFAS. Accessed online at: https://www.epa.gov/pfas/basic-information-pfas

Giesy, John P. and Kurunthachalam Kannan. 2001. Global Distribution of Perfluorooctane Sulfonate in Wildlife. Environ. Sci. Technol. 35: 1339–1342.

Grandjean, P. and R. Clapp. Perfluorinated Alkyl Substances: Emerging Insights into Health Risks. New Solut. 25(2): 147-163.

Hu, Xindi C. et al. (2016). Detection of Poly-and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. Environmental Science & Technology Letters. 3(10), 344-350.

Hansen, K.J., L.A.Clemen, M.E. Ellefson, and H.O. Johnson. 2001. Compound-specific, quantitative characterization of organic fluorochemicals in biological matrices. Environ. Sci. Technol. 35: 766–770.

NSF International. 2017. PFOA/PFOS in Drinking Water. Online at: http://www.nsf.org/consumer-resources/water-quality/drinking-water/perfluorooctanoic-acid-and-perfluorooctanesulfonic-acid-in-drinking-water

Wang, Zhanyun, Jame DeWitt, Christopher Higgins and Ian Cousins. 2017.  A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)? Environ. Sci. Technol: 51(5): 2508-2518. Accessed at: https://pubs.acs.org/doi/full/10.1021/acs.est.6b04806