MSU Extension PFAS Contamination in Agriculture

PFAS, or per- and polyfluoroalkyl substances, are a large group of chemicals (~12,000) sometimes referred to as “forever chemicals” because of the strong fluorine-carbon bond that persists in the environment. PFAS are used to make products water-resistant, heat-resistant or grease-resistant. These chemicals are found in all types of household products such as Teflon-brand cookware, cosmetics, cleaners, fabric treatments, waxes, etc. A common characteristic of PFAS is that they build up in the environment, animals and people, which can lead to serious health impacts such as an increased risk of cancers, decreased fertility, and weakened immune response, among other negative impacts. 

PFAS have been detected globally in surface and groundwater, resulting in drinking water contamination. Nationally, there is limited information on drinking-water PFAS concentrations in public-supply and especially in private wells. A 2023 paper published in Environment International by Smalling et al. estimated that at least one PFAS is detected in about 45% of U.S. drinking water samples and that small public supplies and private wells may be disproportionately affected by PFAS contamination.

PFAS move easily through the ground and can get into groundwater used for some water supplies or for private drinking water wells. When PFAS are released into lakes or rivers, into the air, or through PFAS-containing rainfall-contaminated water, it can get into drinking water supplies. By the end of Fiscal Year 2024, the Michigan PFAS Action Response Team (MPART) identified approximately 330 sites in Michigan where groundwater was above Michigan’s PFAS drinking water criteria. These sites include military bases, landfills, paper mills, tannery waste, airports, wastewater treatment plants, chemical plants, chrome plating plants and other industrial sites. PFAS can get into drinking water when products or wastes containing them are disposed of, used or spilled onto the ground or into lakes and rivers. 

Michigan’s public drinking water supply

Beginning in April 2018, the Michigan Department of Environment, Great Lakes and Energy (EGLE) implemented a statewide survey to test Michigan's public water supplies in several phases of sampling. EGLE developed Maximum Contaminant Levels (MCLs) for seven PFAS compounds in Michigan, which took effect in August 2020.

Michigan Drinking Water Maximum Contaminant Limit

Following the initial compliance monitoring period (August 2020 - February 2021), all municipal water suppliers have been required to conduct ongoing compliance monitoring under the Safe Drinking Water Act and follow a sampling schedule based on whether they can demonstrate their PFAS detections are consistently and reliably below the MCLs. For more information on EGLE’s compliance monitoring of PFAS on public drinking water supplies in Michigan, see the Michigan PFAS Action Response Team’s Compliance Monitoring in Public Water Supplies website. To check the results PFAS testing in public drinking water in your area, check your local municipality's annual Consumer Confidence Report or the MPART interactive map.

Private wells

Approximately 25% of Michigan residents get water from a private residential well. Private well owners are responsible for their own well testing and maintenance. If you do not get a water bill, you likely have a well. Checking your well for the presence of PFAS is very important and not included in standard water testing. If your drinking water supply is contaminated with PFAS, there are ways to remove PFAS from your water such as reverse osmosis (RO) or granular activated carbon (GAC) filters. A list of recommended filters is available on Michigan’s PFAS website.

Home water sampling

It is possible to collect drinking water samples yourself using a home self-test kit provided by a testing lab. Most laboratories will provide their own drinking water sample collection instructions and it is very important to follow the directions carefully. Some instructions may not give explicit instructions on avoiding cross-contamination, but it is still important to ensure you get accurate results. Because PFAS can be found in clothing, cosmetics, dust, food packaging, latex gloves, etc., there is a risk of cross-contamination. PFAS compounds are detected in very small quantities (parts per trillion), so even the smallest cross-contamination could contribute to a false positive sample. Testing for PFAS is not cheap (~$80-$500/sample), therefore, it is important that you take precautions to avoid contamination when collecting a water sample. A list of laboratories certified to analyze for PFAS in drinking water and their fees can be found on the MPART website.

Prepare

After deciding which testing laboratory to use, you must decide where in your home to take the water sample from. It is recommended that samples be taken as close to the well as possible to identify if the water source itself is contaminated without interference from plumbing infrastructure or water treatments, however some consumers prefer to test water coming from their main source of use, such as the kitchen sink. If sampling from an outside spigot, be sure to remove any garden hose or attachments prior to water collection.

PFAS contamination during sampling can occur from a number of common sources such as air fresheners, food packaging, synthetic water-resistant or stain-resistant clothing, dust, personal care products, and certain foods and beverages. Before opening the sample vessel, ensure there has been no recent application of cosmetics, moisturizers, hand creams, sunscreen, bug repellent or related products or use of permanent markers (other than a Fine or Ultra-Fine point Sharpie) that may contain PFAS. Make sure no activities that will cause dust to be airborne are occurring such as dusting,vacuuming or cooking, at the time of sampling.

Wash and dry hands then put on powderless nitrile gloves, taking care not to contact anything that may contain PFAS. Turn the faucet to cold and flush for 2-3 minutes until the water temperature stabilizes to ensure sampling occurs from water recently drawn from the well. If this is not done and there is PFAS leaching from the plumbing infrastructure (for example Teflon plumbing tape), the sample results could be artificially high.

Collect your sample

When removing the lid or cap of the sampling vessel, avoid any contact with the inside. Fill the vessel as instructed by the laboratory and immediately cap. Typically, laboratories will instruct that the water sample be chilled and shipped promptly. Do not ship with gel-type ice packs.

If you are using a test kit that uses absorbent material to contain the PFAS, follow instructions carefully. The water will drain through the absorbent material that will be used for analysis. You then ship back the container of absorbent material, not the water. Best practice is to cover the sample vial while draining to avoid cross-contamination with airborne PFAS, although this could cause a vacuum in the vessel, leading to slower drainage. If the sample does not drain all the way out in the allotted time, either allow more time or, using a Fine or Ultra-Fine point Sharpie, mark the water level on the vessel and dump the remaining water. Recap the sample collection vessel and promptly ship it back to the lab.

Ensure you fill out any paperwork completely and legibly to get meaningful sample results back. If you have questions or concerns about your samples, contact the lab.

Interpreting your results

Typically, the laboratory will send a report with a guide to interpreting your results. It is important to note that laboratories may have different detection limits. Just because a result comes back as ‘non-detect’ does not mean that there are zero PFAS in the water, but that it is at a low enough concentration that the laboratory methods cannot quantify it. Lab methods are improving rapidly, so in the future, labs may be able to provide detections at lower limits. Michigan State University Extension has a guide for more information on interpreting your lab results.

While there is no enforceable standard for PFAS concentrations in private well water, Michigan’s Drinking Water Maximum Contaminant Levels are a good guide to compare your results to. If the well water sample tests higher than the state MCLs, a certified filter for your home drinking water can remove PFAS to protect your health.