Guide to Investigating PFAS Risk on Your Farm

April 21, 2022 Version. Content submitted by Rick Kersbergen, Extension Professor University of Maine Cooperative Extension, Sustainable Dairy and Forage Systems (; This guide was created and will be updated by the Maine PFAS Cohort, made up of representatives from Northern Tilth, LLC, Maine Dept. of Agriculture, Conservation and Forestry, Maine Cooperative Extension, Winslow Agricultural, LLC, Maine Organic Farmers and Gardeners Association, Maine Farmland Trust, The Mitchell Center, and Sheepscot Valley Farm. This work is supported by the USDA National Institute of Food and Agriculture, Farm and Ranch Stress Assistance Network (FRSAN) project 2019-70028-30464 and 2020-70028-32729. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S Government determination or policy.

Please Note: this guide is a living document that will be updated regularly. This version was updated on April 21, 2022 and reflects the best available information at this time. Please bookmark this page and check back on a regular basis for the latest version.

Update made July 25, 2022: Maine PFAS Farmer Wellness Fund

Sections of this Guide:

  1. Status of Maine’s Response to PFAS Contamination at Agricultural Sites
  2. Steps to Determine PFAS Risk Specific to Your Farm
  3. Mitigation Options for PFAS on Farms
  4. Additional Resources

1. Status of Maine’s Response to PFAS Contamination at Agricultural Sites

The state of Maine has allocated significant funding for dealing with issues related to PFAS and is dedicated to supporting the landowners who are affected by land application of wastewater sludge and septage, AFFF, Department of Defense sites, landfills or other PFAS sources.  Maine DEP will be conducting soil and groundwater sampling at all sites that were licensed for land application of Class B biosolids (wastewater sludge and septage).  This equates to over 700 sites around the state.  DEP is prioritizing sampling sites based on many factors, including the volume of material applied, whether materials from multiple generators was spread, whether those materials may have been industrially impacted, and the proximity to receptors (such as residences).

The goal is to have Tier 1 sampling completed in 2023, and sampling of all sites completed by 2025. This means that if a property was or is licensed for land application of wastewater sludge or septage (ie, if it shows up on the DEP’s EGAD Site Types map, more info below), DEP will likely test the affected fields and nearby wells at no cost to the landowner at some point over the next 3 years.  DEP is leading the testing; if DEP testing reveals concerning levels of PFAS at a farm, Maine Department of Agricultural, Conservation, and Forestry (DACF) will automatically become involved.  After a farm is identified by DEP as being “PFAS-impacted,” DACF will conduct and pay for testing of milk, surface water, feed, soil, crops, and livestock (post-mortem) as necessary and work with producers to interpret the results and make management recommendations to try and eliminate PFAS contamination.  In addition, DACF can install water filtration systems for farm wells that test above the 20 ppt Interim Drinking Water screening level.  DACF continues to assess how and where it can offer indemnification to producers.  If farms test for PFAS independently and discover elevated levels, the farm would need to share those test results with DEP and DACF in order to trigger the assistance and supports described above.  If farms conduct private testing for PFAS, and find levels of contamination which exceed state standards, there is potential for the farm to be reimbursed for the analysis costs either by the state (DEP or DACF) if certain criteria are met.  Criteria that the state considers for testing reimbursement are detailed below in section 2.B.

For the most up-to-date information on the state of Maine’s response, check under the heading “Updates and Timeline” on the Per- and Polyfluoroalkyl Substances (PFAS) page (Maine Department of Environmental Protection).

A quick note regarding units of concentration:

PFAS concentrations in soils and other solid materials including biosolids are typically reported by labs and in Maine DEP and Maine CDC literature in parts per billion.  PFAS concentrations in liquids (including water and milk) are typically reported in parts per trillion.

Parts per billion (ppb) and parts per trillion (ppt) are extremely small units of measurement.  A part per billion is equivalent to 1 second in nearly 32 years.  A part per trillion is the same as a single drop of water in 20 Olympic-sized swimming pools.  Measuring at the ppt can be difficult for many laboratories, depending on the individual lab’s level of technology.  However, even at very small concentrations PFAS compounds may be harmful to human health.  See Section 4 of this Guide and Maine CDC’s PFAS Fact Sheet in Appendix A for information on the health risks of PFAS exposure.

1 ppb = 1 ng/g = 1 μg/kg = 1 μg/L

1 ppt = 1 ng/kg = 1 ng/L

2. Steps to Determine PFAS Risk Specific to Your Farm

A. Determine the land application history of your farm

The first step to deciding whether PFAS may be a risk on your farm is determining whether there is any history of residuals application on your farm, dating back to the 1980s.  This may be relatively easy if you have owned your farm all that time, but it is more difficult on land that has changed hands one or more times.  Maine DEP has made several resources available to the public that can assist you in learning whether your land was ever licensed as a land application site for residuals, whether any residuals were actually applied, how much was applied, and in what years. An important caveat:  different classes of residuals and biosolids have different licensing requirements; Class A products have met certain quality criteria that are above the requirements for Class B products.  Class B products are required to be land applied only on fields that fall under a site-specific license.  Class A products can be used anywhere, without a site-specific license required.  This means that certain biosolids products could have been legally spread on land that would not appear in the public records because there was not a site-specific license requirement for use of that particular product.  It is also the case that a site that has been licensed to spread biosolids and may therefore show up in public records as a land application site may have been permitted to spread but may not have actually applied materials to the land. Appendix B provides details on how to research Class B land application history for your farm.

B. Determine whether and how to conduct sampling

If you know that residuals were applied to your land, you may want to sample soil, water, animal forage, crops for human consumption, or some combination of those.

It is possible to collect water samples yourself, provided you follow the strict guidelines that are recommended to prevent contamination of the sample (see Appendix C); however, samples of soil, plant tissue, and other media are recommended to be collected by trained field technicians familiar with PFAS sampling requirements.  Additionally, commercial labs are primarily set up to deal with business clients who send samples on a regular basis; recently there have been reports that some labs may not accept samples from one-time individual clients.  It is important to contact the lab first before conducting any testing on your own to determine the lab’s paperwork procedures, shipping requirements, and sampling protocols.  Here are some general considerations for determining what and how to sample specific to PFAS:

Cost: Each sample will cost between $250-450 (in some cases including extra costs for sample process prior to analysis) in lab analysis fees alone.  For this reason, farmers may want to think carefully and prioritize their sampling efforts in tiers of importance.  If the first round of sampling yields levels of PFAS contamination that are concerning, additional sampling may be needed.  DEP will reimburse landowners for initial analytical costs only (not for labor) if the following criteria are met:

  • An approved lab is used
  • Results are above established screening levels
  • Data is of good quality
  • Data is provided in both report form and electronic data deliverable (EDD)
  • Property is in the immediate vicinity of a sludge or septage land application site or other type of remediation site

MOFGA and Maine Farmland Trust administer a program that will cover the upfront costs of testing. Applications are available here: PFAS Testing Program – Application Form (Google Form). Applications are reviewed weekly. Awarded farmers must agree to share their test results with MOFGA, MFT, and state agencies so high results can be reimbursed. Farmers earning at least 50% of their household income from the farm business and testing related to Tier 1 spreading sites will be prioritized. Testing of purchased inputs needs to be approved by the producer of those inputs.

Type of Sample: Soil, water, milk, animal products and forage, and increasingly, produce are the substances most often sampled on farms.  Understanding the pathways of PFAS through the environment can help to prioritize which materials to sample based on the history and current operations on your farm.  See Part 4 of this guide for more information.  It may make sense to begin with testing the farm’s product (whether that is milk, vegetables, beef, hay, or something else), and expanding to testing soil and irrigation water if concerning levels are found in the product.  The problem with this approach, however, is that screening levels have only been set for two farm products at this time:  milk and beef.  Test results that show zero contamination are helpful in assuring the safety of a product, but without screening levels established by Maine CDC, it is difficult to determine what represents a harmful level of contamination. Maine CDC is working to develop more screening levels for other farm products in addition to milk and beef.  In the meantime, farms will have to carefully consider what type of sampling will provide them with actionable information.

Cross Contamination: Remember, PFAS is found in a multitude of hygiene products, clothing, food packaging, and other consumer products.  It’s easy for either you, your clothing, or your sampling equipment to contaminate a sample with PFAS, especially when you consider that the PFAS compounds are being detected at extremely low concentrations (in the parts per billion, ppb and parts per trillion, ppt).

Choosing a Lab: The State of Maine has approved certain labs to analyze a variety of sample media for PFAS compounds.  See Appendix D for a list of approved labs.  If doing the sampling on your own, you will need to contact the lab ahead of sampling to obtain PFAS-free sampling containers and instructions on how to collect and send the sample, pricing, and turn-around-times.  You’ll need to specify which PFAS compounds you would like to include in the analysis; Maine DEP is currently testing for the “Maine suite of 28” PFAS compounds for many environmental media.  For drinking water, it may make sense to ask for just the 6 compounds included in Maine’s drinking water standard (PFOS, PFOA, PFHpA, PFNA, PFHxS, and PFDA).

C.  Evaluate the Lab Results

Maine DEP has published a helpful guide to interpreting PFAS lab results, which is included here as Appendix E.

The first step in evaluating your results is to compare them to the current PFAS screening levels published by the state of Maine.  The most current set of screening levels, as of the writing of this guide, is from June 2021, and is included here as Appendix F.  These screening levels are expected to be updated and added to as more is learned about PFAS toxicity and behavior in agricultural environments.

Maine’s published screening levels currently include standards for a handful of ingested substances (fish tissue, drinking water, milk, beef), and several screening levels for soil, based on the specific use of that soil.  No screening levels have been issued for vegetables, eggs, or other farm products as of January 2022.


If your drinking water tests above the Interim Drinking Water Standard (20 ppt for the sum of 6 PFAS compounds:  PFOS, PFOA, PFHpA, PFNA, PFHxS, PFDA), it is considered a potential health risk and you should take action to reduce the levels in your drinking water (see Section 4:  Mitigation Options).  If PFAS levels are elevated in drinking water, in addition to the mitigation steps below, it is important to switch to bottled drinking water and work with the DEP to determine if neighbors’ wells may also be contaminated.  Activated carbon filtration systems can also be requested through the DEP for drinking water and farm water.  If the well water is used for watering livestock or for irrigation, there is also a risk that the well water has contributed PFAS to milk, meat, eggs, soil and/or crops, through the pathways described above.


Determining the level of concern for soils is more complicated than for water.  Maine has published PFOS soil screening levels for several crop-specific transport pathways related to dairies and milk production.  These screening levels are back-calculated from what are considered acceptable levels in milk.  Although specific to the dairy system, they are the only agriculture-specific soil screening levels published by the state so far, and for the time being provide the best indication of the levels that may cause concern.

Forage and Produce

Evaluating PFAS levels in forage and produce is even more complicated than for soil.  Maine has yet to publish screening levels for any type of plant tissue. If irrigation water and/or soil levels are high, it can be expected that levels in the forage or produce will also be elevated.   However, without screening levels for produce and forage published by toxicologists at the state or federal level, it is difficult to determine at what point “elevated” PFAS levels equate to a real health risk.  The state of Maine is continuing to research the factors affecting transfer of PFAS from soil to crops and continuing to develop screening standards for farm-produced food products.  Maine’s soil screening standards for the agronomic exposure pathways can help determine when milk is likely to have levels of concern.  The Maine CDC (contact information in Appendix G) is working on action levels for some types of forage and produce, and is a good source of information for questions relative to risk levels.


Maine’s current action level for milk is 210 ppt (ng/l) for PFOS, but this level is very likely to be further reduced in the near future.  The state will not allow milk to be shipped that has exceeded the action level for PFOS.  Any producer whose milk tests over this level should contact Nancy McBrady, Bureau Director, Maine Department of Agriculture, for guidance (see contact info in Appendix G).  If your milk is condemned, the USDA Dairy Indemnity Payment Program (DIPP) can provide some funding for the discarded milk for a limited period of time. You would need to contact the Farm Service Agency (FSA) who would work in conjunction with DACF to facilitate payments for milk or depopulated animals.


Maine’s current action level for beef is 3.4 ppb (ng/g) for PFOS.  Like the level for milk, this action level is expected to be further reduced in the near future.  If farms test their beef and find levels exceeding this action level, the farm should take action to determine the source of PFAS, and reduce the intake of PFAS in the herd.

3. Mitigation Options for PFAS on Farms

With the lack of clarity around what level of PFAS is cause for concern in a variety of agriculture products, especially in forage and produce, it can be difficult to know when and how to take action.  This section attempts to provide some guidance, but this guidance is limited by the gaps in current knowledge related to PFAS toxicity and behavior in the environment.  Although there are no legal requirements to self-report PFAS levels that exceed the published screening levels, if levels of concern are detected on your farm, it is prudent to reach out to the Department of Agriculture Conservation and Forestry (DACF), Department of Environmental Protection (DEP), and/or the Maine Center for Disease Control (CDC) to get the most up-to-date information and support available.  A list of contacts for those agencies is provided in Appendix G.  In addition to accessing state resources, you might consider the following mitigation steps for water, soil, and forage/produce.  The exact mitigation steps will vary from farm to farm, but the current range of options may include:


If well water is above the state’s Interim Drinking Water standard which is 20 ppt for the sum of the following six PFAS: PFOA, PFOS, PFDA, PFNA, PFxHS, and PFHpA, you will want to consider installing an activated carbon filtration system.  If the well supplies drinking water and is located near a land application site for recycled materials such as biosolids (wastewater sludge or septage,) or a remediation-type site as verified by the DEP, it is likely that either Maine DEP or Maine DACF will provide financial assistance for installing an activated carbon filtration system, and will also provide bottled drinking water until the filtration system is installed.  These types of systems have proven effective in removing PFAS compounds from water.  See contact information for ME DEP in Appendix G.


At this point, there are no documented means of effectively reducing PFAS levels in agricultural fields.  The options for soil at this point are limited: either switch the crop grown on the field to one with a lower transport factor (such as switching from hay to corn, or from hay to small grains), or stop using the field for crop production.  Before making drastic changes, it is recommended to reach out to University of Maine Cooperative Extension and/or Maine DACF for guidance on changes in cropping that may lessen risks.

Forage and Produce

Elevated PFAS levels in forage and/or produce is likely resultant of contaminated irrigation water, soil, or both.  If initial sampling only involved forage or produce, and PFAS was detected, it would be prudent to follow up with testing of soil and irrigation water to determine the source of the contamination, and then take the mitigation steps appropriate for water and soil as needed.

For forage, another potential strategy is to dilute affected feed with “clean” feed, thereby lowering the overall PFAS concentration that livestock are consuming. Additionally, routine sampling over a period of months may provide the greatest peace of mind, as the results from a single sample are inevitably limited in how well it represents the entire forage supply.  Even the most carefully collected sample only provides a snapshot of the forage in a bunk, or from a group of hay bales.

Contaminated produce is a more serious problem, mainly because there is a direct route to human consumption (as opposed to the forage-animal-human pathway).  At this time there are no guidelines for safe levels of PFAS in produce intended for human consumption.  The Maine CDC is working to develop more guidelines for specific types of produce.


Although PFAS compounds have been dubbed “forever chemicals” because of their persistence in soils and water, they do have a “half-life” in animals.  This means that once the source of the PFAS in animals’ diets has been removed or reduced, the PFAS levels in the animal will gradually reduce over time.  In lactating animals, one of the major routes of excretion is through the milk.  Once lactating cows are on “clean feed,” the levels of PFOS will eventually decline and the herd may at some point return to acceptable levels in the milk.  Since milk is the major route of excretion of PFOS from dairy cows, it is important to check fresh heifers as they enter the milking string, especially if they had been exposed to contaminated feed and water (both forage and milk when they were calves) and will need to be depurated before their milk should be added to the bulk tank.


If soil and/or forage sampling has revealed PFAS contamination on your farm, the best strategy for beef is to segregate the forage harvested from the contaminated fields, and ensure that only “clean feed” is fed to beef cattle during the finishing stage.  Understanding of half-lives and elimination pathways in beef animals is evolving; farms with specific questions should reach out to DACF or University of Maine Cooperative Extension.

4. Additional Resources

Financial Support

Department of Agriculture, Conservation and Forestry Resources

Where PFAS contamination is confirmed at a farm above screening levels, DACF will test products, additional farm field soils, water sources, and feed to determine and monitor levels of contamination. DACF will pay for these sampling efforts and, in some situations, indemnify the producer for the loss of the value of their livestock. In addition, DACF can reimburse some farms for the cost of PFAS testing that the farm conducted and install water treatment systems for impacted farm water sources. DACF may also be able to provide financial assistance to aid impacted farms, including obtaining clean feed for livestock.  Last, DACF will be launching an income replacement program for PFAS contaminated farms in May 2022.  For information regarding DACF’s resources and support programs, please email or visit the Bureau of Agriculture, Food and Rural Resources, Per- and Polyfluoroalkyl Substances (PFAS) page (Maine Department of Agriculture, Conservation and Forestry Resources website).

MOFGA and Maine Farmland Trust
PFAS Emergency Relief Fund

MFT and MOFGA are jointly administering a PFAS emergency relief fund to support any Maine farm dealing with potential per- and polyfluoroalkyl substances (PFAS) contamination.

The fund has three primary purposes at this time:

  • To provide short-term income replacement for farms that the Department of Agriculture, Conservation and Forestry (DACF) has identified as having high test results.
  • To help pay for initial PFAS testing on farms that choose to do their own testing.
  • To support access to mental health services for impacted farmers.

Income Replacement Grants from MFT and MOFGA:

Income replacement: Contact Nancy McBrady at, 207.287.7522 and request a referral that will make you eligible for the Income Replacement Program/PFAS Emergency Relief Fund (MOFGA website) administered by the Maine Organic Farmers and Gardeners Association (MOFGA) and Maine Farmland Trust (MFT).

To enroll in the Income Replacement Program, confirm that you earn at least 50% of your family income from your farm business, you have stopped sales of contaminated products, and we have received a W-9 Request for Taxpayer Identification Number and Certification form (PDF), (IRS website) and a recent Schedule F (or other IRS tax filing form used by your farm business) from you. You will then be enrolled and paid weekly through MOFGA and MFT until the state indemnity program by DACF begins or the fund runs out of money. Participants agree to have their Income Replacement award deducted from the lump sum payment they receive from the Maine indemnity program in order to replenish the emergency fund that will continue to support contaminated farms.


To connect in a confidential space with other farms impacted by PFAS contamination please contact to be added to a Google Group.

Crisis Support

Maine PFAS Farmer Wellness Fund

This fund is intended to holistically support Maine farmers and Maine farm workers impacted by PFAS contamination. The Maine PFAS Farmer Wellness Fund is part of the Maine Organic Farmers and Gardeners Association and Maine Farmland Trust PFAS Emergency Relief Fund. It is being administered in partnership with the Maine Farm and Ranch Stress Assistance Network, which is a project of the University of Maine Cooperative Extension.

Department of Agriculture, Conservation and Forestry Resources

Where PFAS contamination is confirmed at a farm above screening levels, DACF will test products, additional farm field soils, water sources, and feed to determine and monitor levels of contamination. DACF will pay for these sampling efforts and, in some situations, indemnify the producer for the loss of the value of their livestock. In addition, DACF can reimburse some farms for the cost of PFAS testing that the farm conducted and install water treatment systems for impacted farm water sources. DACF may also be able to provide financial assistance to aid impacted farms, including obtaining clean feed for livestock.  Last, DACF will be launching an income replacement program for PFAS contaminated farms in May 2022.  For information regarding DACF’s resources and support programs, please email or visit the Bureau of Agriculture, Food and Rural Resources, Per- and Polyfluoroalkyl Substances (PFAS) page (Maine Department of Agriculture, Conservation and Forestry Resources).

Background Information and Understanding PFAS Pathways

PFAS compounds have been used in numerous consumer products since the 1950s and traces of these compounds have become ubiquitous in the environment.  Because of their chemical structure, these compounds do not readily break down in the environment; consequently, levels accumulate over time in environmental media such as soil and water, and in animals including humans.  According to the National Institute of Environmental Health Sciences (NIEHS), there are more than 4,700 PFAS compounds in existence, and the number is still growing as industry invents new forms within this chemical class.  Scotchguard™ (by 3M) and Teflon™ (by Dupont) are examples of product coatings that contain two of the most common PFAS compounds – PFOA and PFOS.  Aqueous fire-fighting foam (AFFF) is another product containing these compounds.  Companies like 3M and DuPont have phased out a handful of the most commonly used PFAS compounds since the early 2000s, but PFOA and PFOS may still be produced and used in products imported from overseas. Additionally, newer, less-studied compounds continue to be approved for use by the EPA.  The CDC estimates that PFAS can be found in the blood of 97% of Americans, though recent reports indicated that the blood levels of PFOS and PFOA are declining due to the phase out of these two compounds in the US. According to the U.S. Agency for Toxic Substances and Disease Registry, some, but not all, studies have shown that PFOS and PFOA may increase cholesterol levels, decrease how well the body responds to vaccines, increase liver enzymes, increase risk of high blood pressure or pre-eclampsia, decrease infant birth weight, and high PFOA exposure may increase the risk for kidney and testicular cancer. The Maine CDC has published a fact sheet regarding the potential health effects of PFAS chemicals, which is included here as Appendix A.

Although PFAS contamination in other states has been linked, in some cases, to direct discharge from industrial manufacturing facilities, in Maine the contamination is more likely to be either from the site of an AFFF discharge (such as military bases or fire training facilities), closed landfills or is linked to the land application of waste water treatment residuals (including land application of septage).  When waste water is treated, there are two products:  clean water, which is recycled back to rivers and the ocean, and solids (wastewater sludge), which are either landfilled, sent to an incinerator, or further processed into “biosolids” for land application on farm fields.  (Note:  The terms “sludge” and “biosolids” are often used interchangeably.)  Land application of sludge/biosolids has been considered a “beneficial reuse” for decades, because it returns nutrients and organic matter to the soil.  Wastewater treatment facilities may receive residential wastewater, industrial wastewater, or some combination of the two. Industrial wastewater, if coming from a factory that used PFAS compounds in its operations, is likely a greater contributor of PFAS than residential wastewater.  For this reason, the residual materials produced by different wastewater treatment facilities, and at different points in time, may have very different levels of PFAS, depending on the unique mix of wastewater coming into the facility at any given time.  Because of the phase-out of PFOS and PFOA beginning in 2001, more recent biosolids are likely to have significantly lower levels of these compounds than material that was spread in the 1980s and 1990s.  Materials produced at wastewater treatment facilities with industrial wastewater inputs are likely to have higher levels than facilities that receive primarily residential wastewater.   Improvements in modern laboratory techniques means that we can now measure these compounds in soils and other media at the extremely low concentrations in which they may be affecting human health.

Since 2019, Maine DEP has taken many steps to evaluate the levels of PFAS in soil and groundwater resulting from the land application of sludge and septage, which in many cases took place at agricultural sites.  As Maine DEP continues to roll out its soil and groundwater investigation to a statewide program, data obtained to date has indicated that PFAS levels are not uniform at different sites where biosolids were applied. As the investigation continues, the DEP is hoping to learn more about where PFAS is at the highest levels and how it moves within the environment. While there have been some documented cases in Maine where biosolids use has contributed to exceptionally high levels of PFAS in soils and groundwater, there are also many examples where long-term use of biosolids has resulted in mildly elevated, but not extremely high levels in soil and groundwater.

Maine is one of only a few states that has published screening levels for PFAS for soil and milk.  A screening level is a concentration of a chemical in an environmental medium that serves as a threshold to determine if further action (beyond analysis) is needed.  Maine was one of the first states to establish soil screening levels for some PFAS compounds as they apply to sites receiving biosolids (2.5, 5.2 and 1,900 parts per billion for PFOA, PFOS and PFBS, respectively).  Maine, along with six other states (including New Hampshire, Vermont and Massachusetts), has also developed enforceable PFAS drinking water standards that are more restrictive than the EPA’s current guidelines.  Maine’s current drinking water standard is 20 parts per trillion, compared to EPA’s current guideline of 40 parts per trillion to trigger further evaluation and 70 parts per trillion as a remediation goal.  There are still many unknowns related to how PFAS travels through the environment and what represents a “safe” level.  Maine’s guidelines can be expected to continue to be updated as the science of PFAS evolves. This guide is based on the best information available at this time, but it is expected that “safe” levels will ultimately be lower than currently adopted.

Understanding Pathways of Exposure

We are all exposed to PFAS from a variety of sources in everyday life – stain-resistant carpeting, nonstick cookware, grease- and water-proof food packaging, fabric softeners, waterproof clothing, cosmetics, and many other products contain this class of chemicals.  When we wash dishes, clothing, and attend to our own hygiene, all of that wastewater goes either to a septic system or a public wastewater treatment facility.  Industrial factories such as paper mills that use PFAS and other facilities may also contribute their wastewater to public treatment facilities or generate sludge at their own wastewater treatment plants.  The solids that are either pumped from a home septic system, or are left over from the wastewater treatment process, are referred to as sludge, and this sludge is often processed to reduce pathogens. After processing (which may take the form of composting or lime-stabilization), the sludge material is known as “biosolids.”  In Maine and many other states and countries, biosolids are often applied to agricultural fields.

The concentration of PFAS in a field will vary depending on how many times the field was applied, the application rate, and the exact type/source of the biosolids or residual material.  The biosolids produced at different wastewater treatment facilities may have different levels of PFAS contamination, depending on the relative amounts of residential vs. industrial waste streams entering the facility.  The time period in which the material was applied is also a factor; the two most commonly studied PFAS compounds, PFOA and PFOS, were much more widely used in the 1980s and 1990s, and have been mostly phased out beginning in 2001.  Farm fields that were repeatedly spread prior to 2001 may have higher levels of PFOA and PFOS, compared to those that were spread with biosolids after 2001.

A quick note on background levels:

If your land has no history of biosolids use, and is not located adjacent to a parcel with a history of biosolids use, firefighting foam use (often associated with Department of Defense sites) and/or PFAS manufacturing plants, it is unlikely that your soil and well water are highly contaminated.  However, it is still possible that testing for PFAS could still reveal trace levels in soil, which are referred to as background levels.  A study by the University of Vermont which has been widely cited indicates that presumed background levels in soils from Vermont towns and parks have a median concentration of 0.39 ppb for PFOA and 0.68 ppb for PFOS.  Maine is currently working on a similar state-specific study of background concentrations in agricultural soils that the DEP anticipates will be available sometime in early 2022.

Other sources of PFAS to soil include irrigation water, aerial deposition, and potentially even rainwater. If PFAS have found their way to groundwater, irrigation water pumped from a drilled or dug well may be contaminated, and the PFAS from that contaminated water may build up in the irrigated soil over time. There are also a few documented cases of elevated levels of PFAS in soils in the vicinity of manufacturing facilities that used PFAS in their processes in southern New Hampshire, southwestern Vermont, and upstate New York; these elevated levels are believed to be due to deposition of airborne PFAS compounds.  Rainwater can also be a factor contributing to what would be considered “background” levels of PFAS on fields that may have never received any biosolids.  At least one study has documented measurable levels of PFAS in rainwater, but further study is needed to confirm this pathway.  Groundwater can also be impacted by sources other than biosolids, such as leaking residential septic systems.

Once PFAS have accumulated in soil, they tend to stay in the soil, although some also leaches to groundwater. There are two pathways for PFAS in soil to make their way into plants:  through direct uptake by roots, and through physical contamination of the edible portion of the plant (above-ground or below-ground) coming into contact with the soil and adhering to the harvested plant material.  Preliminary research indicates that different parts of plants take up PFAS at different rates, and that vegetative parts of plants (leafy greens, grass forages, etc) take up more PFAS than the fruiting parts of plants (which includes grains).  Initial investigations by Maine CDC and the University of Maine Cooperative Extension indicate that corn silage is less likely to take up PFAS compounds into the plant than is grass, and that transfer to grain corn is minimal to none.  Ongoing research is needed to refine and verify these findings, but for now, these apparent differences in uptake rates by different types of crops provide producers with options on how to mitigate the risks of elevated PFAS levels in their soils, as discussed above in Section 3 of this guide.

If irrigation water and/or wash water is contaminated, then in addition to the pathways described above for soil-to-plant transport, there is the added pathway of contaminated water coming into direct contact with the above-ground portions of the plant.

This work is supported by the USDA National Institute of Food and Agriculture, Farm and Ranch Stress Assistance Network (FRSAN) project 2019-70028-30464 and 2020-70028-32729.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S Government determination or policy.

Appendices A-G

Appendix A:  Maine CDC PFAS Fact Sheet

State of Maine Dirigo seal/logoJanet T. Mills Governor | Jeanne M. Lambrew, Ph.D. Commissioner

Maine Department of Health and Human Services Maine Center for Disease Control and Prevention
11 State House Station 286 Water Street, Augusta, Maine 04333-0011
Tel: 2072878016 | Fax 207.287.9058

PFOS, PFOA and other PFAS Questions and Answers

What are PFOS, PFOA and PFAS?

PFOS and PFOA belong to a family of chemicals referred to as perfluoroalkyl substances or PFAS for short. PFOS (perfluorooctanesulfonic acid) and PFOA (perfluorooctanoic acid) are two chemicals in this family that were made in the largest amounts in the United States. Some other chemicals in this family that have been found in Maine soils and water are:

  • PFNA (perfluorononanoic acid)
  • PFHxS (perfluorohexanesulfonic acid)
  • PFHpA (perfluoroheptanoic acid)

PFOS and PFOA were used for a long time in many household and industrial products. These chemicals were used to make products to repel water and resist stains and grease. PFOS and PFOA were used to make carpet, fabric, clothing, food packaging, pots and pans, and personal care products. They were also used in some factories and were a key ingredient in some fire-fighting foams. Most companies have stopped using these two chemicals.

How might you come into contact with PFOS, PFOA and other PFAS?

Almost everyone has some PFOS or PFOA in their bodies because these chemicals were in so many consumer products and for many years. For most of us, the amount of these chemicals in our bodies have been decreasing as the use of PFAS in consumer products has been phased out.

Low levels of PFOS, PFOA and other PFAS are also present in our environment. Higher levels are sometimes found near airfields that may have used fire-fighting foams, factories that used these chemicals, or land with a history of using certain waste materials or biosolids containing PFOS, PFOA, or other PFAS.

Crops may be grown on soil that has these PFAS, but how much of these chemicals are in the crop depends on the type of crop, what part of the crop is edible, soil properties, and levels in the soil. These chemicals may end up in the milk and meat of animals fed crops like hay containing PFAS. These chemicals can also move from the soil into the ground water and into well water. Consuming contaminated milk, meat, plants, or water are potential ways people can be exposed to these chemicals.

How can PFOS, PFOA and other PFAS affect my health?

Scientists are still learning about the possible health effects from being exposed to PFAS. Most health studies so far have focused on PFOS and PFOA.

According to the U.S. Agency for Toxic Substances and Disease Registry, some, but not all, studies have shown that PFOS and PFOA may:

  • increase cholesterol levels;
  • decrease how well the body responds to vaccines;
  • increase liver enzymes;
  • increase risk of high blood pressure or pre-eclampsia in pregnant women;
  • decrease infant birth weight.

It is unclear if PFAS exposure directly causes cancer. Some studies show people exposed to high levels of PFOA may have an increased risk of kidney cancer or testicular cancer. Fewer studies have found a link between PFOS and increased cancer-risk. The studies on PFAS exposure and cancer all have limitations. For example, not all PFAS studies have made sure that other known risk-factors like smoking are not the cause of cancer. Some studies with laboratory animals, mostly with PFOA, have also shown higher exposures can cause cancer.

Should I test my blood for PFOS, PFOA, or other PFAS?

Blood test results will only tell you the levels of PFOS, PFOA and other PFAS in your blood and whether they are high or low compared to typical levels found in the United States population. Most people in the United States have very low amounts of PFAS in their blood because of the wide-spread use in consumer products. Individuals that are consuming foods or water contaminated with PFOS, PFOA or other PFAS may have higher levels in their bodies.

A blood test will not provide information on whether any PFAS are causing a current health problem, nor will a blood test predict a health problem. There are no health-based screening levels to which your doctor can compare the levels measured in your blood. There are also no treatments that will directly result from having a blood test for PFAS.

Public health officials sometimes perform studies where they collect blood samples from a larger number of individuals to learn if there is community-wide exposure. This helps understand the kinds and amounts of PFAS exposures in a community and how they compare to other populations.

If you are concerned about a known PFAS exposure it is best to talk with your doctor to decide whether to test for these chemicals.

If you have questions about PFOS, PFOA, or other PFAS in the environment, blood testing, or health effects, please contact one of our toxicologists at 866.292.3474 (toll-free in Maine), 207.287.4311, or Maine Relay 711.

Maine Department of Health and Human Services logo
— Updated 09/22/2020

Appendix B:  Historical Spreading Data available from ME DEP

A general note regarding use of the “Maine EGAD Site Types” Online Map:  This mapping tool is under development and is continuing to be updated as more information is gathered.  In some cases, the map shows sites that were licensed for spreading, but which never received any material.  In other cases, sites that were land-applied with residual materials may not be indicated on the map.  The DEP welcomes any information from citizens that can help them continue to improve their data.  Landowners can contact with questions, corrections, or other information related to the map data.

Another important caveat:  This map will only show sites that have been licensed for the land application of Class B biosolids.  Class A biosolids do not require a site-specific license, and therefore could be spread anyway.  The historical information provided by the map is helpful in piecing together the history of a property, but in many cases may not reflect the full history of biosolids application on any given property.

There are two important resources to be used in tandem if you want to find out whether a piece of land has a history as a biosolids land application site:  the EGAD Site Types map, and the DEP’s historical land application records.

1. EGAD Site Types Map: Visit the Maine EGAD Site Types, Environmental and Geographic Analysis Database (EGAD) page.

You can type an address into the search box to go to a specific location and see whether the site is marked with the symbol for “sludge utilization site” or “residuals utilization site”

symbol and text that represent sludge utilization site symbol and text that represent residuals utilization site

If your land has one of these symbols, you click on the symbol to get more information about the site.  The description will give you basic details about the site history, including the source of the material, but will not include details such as how much material was applied.  If you want to learn how much material was applied, the application year, the source, and exactly where it was applied, you’ll need to dig further in the publicly available spreadsheet described below.

Additionally, a separate but related map shows PFAS test results gathered by DEP thus far: Visit the Maine Department of Environmental Protection, PFAS Data Map page.

2.  DEP spreadsheet entitled 2020-11-12-sludge-bioash-land-application (Excel),

Note: This spreadsheet represents the best information DEP had in November 2020. The spreadsheet has continued to be updated with corrections since then, but the most updated version is not publically available at this time.

    1. To find spreading information for your land base, obtain the following data from the Maine EGAD Site Types map:
      1. Site Name(s)
      2. Licensee(s) (the producers of the residual material…usually a municipal wastewater treatment facility)
    2. Open the spreadsheet and click on the tab labeled “All Spreading Activities”.  Use the Find function (CTRL + F) to search for your site name.  Click through all of the entries for the site, taking note of the names of all of the Licensees (treatment facilities) associated with the site.
    3. There is a spreadsheet tab for each licensed producer of biosolids.  For each Licensee associated with your land:
      1. Open the spreadsheet tab for that Licensee.
      2. Under the heading “Licensed Land Application Sites,” find your site name.  Take note of the license #, which can be helpful when requesting records from DEP.  Also double-check that the town is correct.
      3. Scroll down further in the spreadsheet, to the heading “Spreading Activities (as reported in annual reports)”.  Here you’ll find each spreading activity that was reported, including the volume spread.  Again, using the “Find” function is helpful to locate all the records for your site.  Recommend copying and pasting the entries pertinent to your farm into a separate spreadsheet for your records.
      4. Repeat this process for each entity that was licensed to land-apply on your land to determine the total amount applied.  Note that in many cases, a single site may have been further subdivided into smaller fields.  The names of these smaller subsections may or may not be noted on the Maine EGAD Site Types map.  If they are not, it is hard to know exactly how much material was spread and where.  See below for further instructions on obtaining more detailed site maps.

3.  Obtaining Site Maps

It is often necessary to obtain site-specific maps, which include field names that correspond to the spreading records from the spreadsheet mentioned above.  To obtain these specific maps, you can email Maine DEP at to request site-specific info such as maps or the original application file.

Appendix C:  Homeowner Guidance for Sampling Well Water

The state of Michigan has published PFAS sampling protocols in a user-friendly format, which includes a detailed list of prohibited clothing, hygiene products, and other materials that need to be carefully avoided when sampling for PFAS:

Additionally, the state of Maine has provided specific guidance to homeowners on the process of collecting samples and submitting results to DEP.

Appendix D:  Maine DEP-approved PFAS Testing Labs

Maine Laboratory Accreditation Program
Accredited PFAS Laboratories*

There are currently no laboratories in Maine that are accredited to analyze for PFAS. Public Water Systems may wish to contact their regular in-state lab to determine if they have a subcontracting relationship with an out-of-state lab accredited for PFAS analysis.

Laboratory  Name/Address Phone Number Website Address
TestAmerica Laboratories, Inc. (CA)
880 Riverside Parkway West
Sacramento, CA 95605
Eurofins Eaton Analytical, LLC
750 Royal Oaks Drive, Suite 100
Monrovia, CA 91016
Vista Analytical Laboratory, Inc.
1104 Windfield Way
El Dorado Hills, CA 95762
Eurofins Eaton Analytical, LLC
110 South Hill Street
South Bend, IN 46617
Alpha Analytical – Mansfield Laboratory
8 Walkup Drive
Westborough, MA 01581
Batelle Analytical Chemistry Services
141 Longwater Drive, Suite 202
Norwell, MA 02061
Con-test, A Pace Analytical Laboratory
39 Spruce Street
East Longmeadow, MA 01028
SGS North America Inc.
5500 Business Drive
Wilmington, NC 27516
Absolute Resource Associates
124 Heritage Ave, Unit 16
Portsmouth, NH 03801
EMSL Analytical, Inc.
200 Route 130 North
Cinnaminson, NJ 08077
Eurofins Lancaster Laboratories Environment, LLC
2425 New Holland Pike
Lancaster, PA 17601
Pace Analytical Services, LLC
8 E. Tower Circle
Ormond Beach, FL 32174
GEL Laboratories, LLC
P.O. Box 30712
Charleston, SC 29417
ALS Group USA Corp., DBA ALS Environmental (WA)
1317 S 13th Avenue, Kelso, WA 98626

*Note: Accreditation status is subject-to-change (current as of 01/14/2022). Please verify the Maine accreditation status, with the laboratory, prior to ordering sample kits.

Appendix E:  How to Interpret Lab Data Reports

How to Read and Interpret my PFAS Laboratory Data Report

Laboratory data reports may at first seem difficult to read and interpret.  Although required information is included in the report, each laboratory may present the information in differing ways. In general, each laboratory report must include a cover page, a list defining abbreviations used in the report, a summary of issues that the laboratory may have had during sample analysis, a report of sample results including dates and times of sample collection, sample receipt, sample preparation and analysis, several sections summarizing laboratory quality control measurements, and a copy of the chain of custody form and related sample receipt documentation.

Example Report of Sample Results:

(Click on the link in bold for definition/explanation below the chart)

Parameter Result Units Qualifier RL MDL Dilution Factor
Perfluorooctanoic Acid (PFOA) 21.2 ng/L 1.95 0.230 1
Perfluorooctane Sulfonic Acid (PFOS) ND ng/L U 1.95 0.491 1
Result = The concentration of the compound  detected
This number is compared to Maine’s Interim Drinking Water Standard, which is currently 20 parts per trillion
ND = Non-Detect
ND means the compound was not detected at a level high enough for the laboratory equipment to detect
RL = Reporting Limit
The RL is the limit to which the laboratory equipment can reliably report under normal laboratory conditions
MDL = Method Detection Limit
The MDL is the lowest concentration that the laboratory test equipment can detect a contaminant

Note: ng/L = Nanograms per liter or parts per trillion (ppt)

Laboratory Quality Control

A testing laboratory is required to implement a series of practices to ensure that results generated during the testing of samples are accurate and complete. Each laboratory report will include several pages of quality control information. This information can easily be confused with actual sample results. Actual sample results will be labelled as such and include a specific sample identification number, client identification number, and sample location. Quality control data will include terminology such as method blank analysis, batch quality control, lab quality control analysis, matrix spike analysis, and lab duplicate analysis. Each laboratory report is reviewed by qualified DEP staff prior to sending you the data to ensure that the data are of high quality and dependable. If not, DEP staff may ask to repeat the sampling and testing.

Common Laboratory Data Qualifiers

Each laboratory report should include a list defining abbreviations used in the report. Laboratories do not all use the same abbreviations, so it is important to check the list included in the report.  The most common abbreviations, called data qualifiers, used by a laboratory are as follows:

Qualifier Definition
B The compound was detected in a blank sample. This is a quality control measure that defines whether there is uncertainty in the source of contamination. B qualifiers indicate the sample result may be biased high.
U The compound was not detected at a level greater than the laboratory method detection limit (MDL).
J The compound was detected at a level greater than the laboratory MDL and less than the reporting limit. J qualifiers indicate an unknown bias to the sample result.
E The compound was detected at a level that exceeded the laboratory instrument calibration curve. E qualifiers generally indicate a low bias to the sample result. Compounds with an E qualifier will have another result reported for a diluted analysis to bring the compound within the laboratory calibration curve. This result is generally on a subsequent page in the report.
F, Q or I F, Q or I qualifiers generally indicate a high bias to the sample result and the reported result should be considered a maximum concentration.

How is the Sum of 6 Calculated?

In June 2021, the Department began applying an interim standard of 20 ppt (ng/L) for the sum of 6 PFAS in drinking water.  These compounds are PFOA, PFOS, PFNA, PFHpA, PFHxS and PFDA.

Results above the reporting limit are used in the calculation as reported in the laboratory report. Results reported with a “J” qualifier are below the reporting limit and above the laboratory method detection limit (MDL) and are used in the calculation as shown in the laboratory report. Non-detect (ND) results are below the laboratory MDL, and a value of zero is used in the calculation.

The table below illustrates how the Sum of 6 is calculated:

Compound Result from Lab

Report (ng/L

Qualifier Reporting Limit (ng/L) Result used in Calculation


PFOA 170 1.8 170
PFOS 185 B 1.8 185
PFNA 10 1.8 10
PFHpA 142 1.8 142
PFHxS 0.242 J 1.8 0.242
PFDA ND U 1.8 0
Calculated Sum of 6 507

Where can I find more information?

Maine Department of Environmental Protection logo/sealMaine Department of Environmental Protection |

Appendix F:  Maine PFAS Screening Levels

Note: These screening levels are expected to be updated in the coming year.  Check the Maine DEP PFAS website for the most recent version.

Maine PFAS Screening Levels, June 2021

Soil Remedial Action Guidelines1 (mg/kg)
Compound Leaching to Groundwater Residential Commercial Worker Park User Recreator Sediment Construction Worker
PFBS 7.1 1,700 22,000 4,900 5,700 51,000
PFOS 0.0036 1.7 22 4.9 5.7 5.1
PFOA 0.0017 1.7 22 4.9 5.7 5.1

Soil Beneficial Use2 (ng/g, dry weight)
Compound Beneficial Use
PFBS 1,900
PFOS 5.2
PFOA 2.5

Recreational Angler RAGs3 (mg/kg wet weight)
Compound Fish Tissue
PFOS 0.052
PFOA 0.052

Interim Drinking Water Standard4 (ng/l or ppt)
Compound Residential

Milk5 (ng/l or ppt)
Compound Action Level
PFOS 210

Beef6 (ng/g)
Compound Action Level
PFOS 3.4

Dairy7 – PFOS Crop-Specific Soil Screening Levels (ng/g dry weight)
Soil to Hay to Milk Screening Level Soil to Corn-Silage to Milk Screening Level Soil to Hay and Corn-Silage to Milk Screening Level
Grass-Based  Farm 6.8 120.0 6.4
Average Maine Farm 13.8 54.8 11.0

Helpful Conversions: 0.000001 ppm = 0.001 ppb = 1 ppt

Parts Per Million (ppm) Parts Per Billion (ppb) Parts Per Trillion (ppt)
1 milligram/kilogram (mg/kg) = 1 ppm

1 milligram/liter (mg/l) = 1 ppm

1 microgram/gram (μg/g) = 1 ppm

1 microgram/kilogram (μg/kg) = 1 ppb 1 microgram/liter (μg/l) = 1 ppb

1 nanogram/gram (ng/g) = 1 ppb

1 nanogram/kilogram (ng/kg) = 1 ppt

1 nanogram/liter (ng/l) = 1 ppt

1 picogram/gram (pg/g) = 1 ppt

1 — Maine Department of Environmental Protection (Maine DEP), Maine Remedial Action Guidelines (RAGs) for Contaminated Sites (PDF), effective May 1, 2021.

2 — Maine DEP, Maine Solid Waste Management Rules: Beneficial Use of Solid Wastes, 06-096 C.M.R. ch. 418 (Word), Appendix A, last amended July 8, 2018.

3 — Maine DEP, Maine RAGs for Contaminated Sites (PDF), effective May 1, 2021.

4 — Resolve 2021, ch. 82, Resolve, To Protect Consumers of Public Drinking Water by Establishing Maximum Contaminant Levels for Certain, Substances and Contaminants (PDF), Emergency, effective June 21, 2021.

5 — Maine Center for Disease Control and Prevention (CDC), Action levels for PFOS in cow’s milk (PDF), Memorandum to Rachael Fiske, Maine Department of Agriculture, Conservation and Forestry (DACF), from Andrew Smith, SM, ScD and Thomas Simones, Ph.D., Maine CDC, March 28, 2017.

6 — Maine CDC, Action levels for PFOS in beef for use in determining whether beef at a farm is adulterated (PDF), Memorandum to Nancy McBrady, Maine DACF, from Andrew Smith, SM, ScD and Thomas Simones, PhD, Maine CDC, August 4, 2020.

7 — Maine CDC, Derivation of PFOS soil screening levels for a soil-to-fodder-to-cow’s milk agronomic pathway (PDF), September 16, 2020.

Maine Department of Environmental Protection logo/sealMaine Department of Environmental Protection |

Appendix G:  State Resources

State Government Resources

Maine Department of Environmental Protection (DEP) is undertaking a multi-year effort to test soil and water at licensed biosolids land-application sites, and are embarking on this effort in a prioritized fashion.  Priority will go to sites that received the highest volumes, received from multiple generators, received from a generator that processed industrial wastewater inputs, or sites with close proximity to residential wells. To contact Maine DEP regarding any questions related to PFAS, email or call 207.287.5842. You can also visit DEP’s PFAS website on the Per- and Polyfluoroalkyl Substances (PFAS) page.

Maine Department of Agriculture, Conservation, and Forestry is also actively providing support to farmers dealing with PFAS contamination.  DACF works with all types of commercial farms, ranging from dairy to livestock to produce. To contact the Maine Bureau of Agriculture, Food and Rural Resources for PFAS questions and support, email You can also visit the Bureau of Agriculture, Food and Rural Resources, Per- and Polyfluoroalkyl Substances (PFAS) page (’s Maine Department of Agriculture, Conservation, and Forestry website).

Maine Center for Disease Control (CDC) has toxicologists on staff who are deeply involved in assessing PFAS risk by determining screening levels intended to protect human health.  If you have high PFAS test results in your drinking water or produce (or other substances intended for human consumption), you may consider reaching out to State Toxicologist Andy Smith at 207.287.5189 or

Other Resources:

Maine Organic Farmers and Gardeners Association (MOFGA) is providing various forms of support to farmers who are concerned about PFAS risk. Visit the Maine Organic Farmers and Gardeners Association (MOFGA) website.

Maine Farmland Trust (MFT) is also working to support farmers and protect Maine farmland in the face of PFAS.  They have a dedicated PFAS in Maine Agriculture page (Maine Farmland Trust (MFT) website).

This work is supported by the USDA National Institute of Food and Agriculture, Farm and Ranch Stress Assistance Network (FRSAN) project 2019-70028-30464 and 2020-70028-32729.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S Government determination or policy.