At this time, we do not have enough research to predict how much PFAS will end up in a specific crop, and there are not federal standards for PFAS levels in plants. Plant uptake of PFAS appears to vary according to a number of factors, such as: a) the concentration of PFAS in the soil and water; b) the type of soil; c) the type of plant being grown; d) the plant part that is used for food or feed; and e) other nutrients and components in the soil.
More research is needed to quantify the amount of PFAS that could accumulate in plants grown in soils or irrigated with water contaminated with PFAS, and to determine standards for safe levels. Since people eat a variety of foods, the risk from the occasional consumption of produce grown in soil or irrigated with water contaminated with PFAS is thought to be low. However, because these chemicals can accumulate in the body and people can be exposed from a variety of sources, it is recommended to avoid or minimize known PFAS exposures whenever possible.
If you are concerned that your water may contain PFAS and you are on municipal water (meaning, you receive a water bill), view the results of the Michigan Department of Environment, Great Lakes, and Energy (EGLE's) 2018 statewide public water supply sampling effort. (This site also contains results from sampling of schools on their own wells, and many child care centers and Head Start Programs). If you are concerned that your water may contain PFAS and you are on a private well, visit our Home Sampling Guidance page to learn how you can take and analyze your own residential water sample. For other questions, contact the State of Michigan Department of Health and Human Services Environmental Health Hotline at 800-648-6942.
In the meantime, use rainwater, filtered water, or water from another safe source for your garden. Another option is to plant a garden in raised beds that contain new, clean soil, while using clean water for seedlings and garden plants for the entire growing season. Wash the produce in clean water after harvesting. It is recommended that you peel and wash root vegetables before eating them.
In summary, we are not able to determine a "safe" level of PFAS in soil, irrigation water, or groundwater for gardening at this time. The best we can do is identify ways to decrease the exposure of garden plants to PFAS, which would include the following:
- If the irrigation water contains PFAS switch to rainwater, filtered water, or water from another safe source for your garden.
- If the soil contains PFAS create raised beds with clean soil, underlaid with heavy-duty landscape fabric (polypropylene is a good choice). Ensure the roots of your plants do not extend past the clean soil.
- If the groundwater contains PFAS ensure the roots of your plants do not extend into the groundwater.
- Add clean organic matter to the soil (uncontaminated peat, manure, or compost). Studies have shown that as soil organic matter increases plant accumulation of PFAS decreases.