In 2014, the United Nations declared December 5^th as World Soil Day to raise awareness of soil as a critical component of the natural system and as a determinant of human and animal health. Sadly, ignorance and disregard that have led to poor soil quality and dangerous soil pollution across the globe. PFAS (per- and polyfluoroalkyl substances) can be found throughout our environment in every community, park, school yard and the soil in which we raise our food.  In this article, we will review mechanisms for soil contamination and remediation.

Our last article in this series discussed PFAS in the water supply. Contaminated water is one of the leading pathways for PFAS to accumulate in the soil. PFAS in water used for plants, lawns or crops repeatedly introduces soil contamination. Likewise, contaminated rainwater contributes to PFAS accumulation in the soil. But contaminated water is not the only source of PFAS soil contamination. PFAS spills, whether accidental and intentional, and leakage of stored PFAS are major industrial contributors to soil contamination.  Everyday consumer trash is just as guilty. Landfill disposal of PFAS-containing products results in the leaching of PFAS into the soil in and around the landfill. The soil not only absorbs the PFAS but, because PFAS chemicals repel water by design, the PFAS becomes embedded in the particles that make up the toxin-laden soil. Wind-blown soil spreads PFAS contamination.

Think you are avoiding PFAS by buying certified organic products? Think again. Agricultural soil around the world is fortified using biomass-derived fertilizers, including animal manure and other biosolids. Certified organic farms make heavy use of these biosolids-based fertilizers. PFAS in the food chain accumulates in plants, animals and people that, in turn, produce the biosolids. When contaminated biosolids are used as organic fertilizer, PFAS soil contamination is compounded with each application. (The challenges of PFAS in the food chain will be discussed in our next article.)

Government agencies, agricultural producers, industrial facilities and environmental organizations have used various technologies in an attempt to remediate PFAS-contaminated land. The field scalable technologies used for decades (soil incineration and solvent washing) have been shown in the scientific literature to be both too costly and generally ineffective. Existing small-scale technologies are promising but have not been successfully scaled to a viable environmental clean-up method.

Nearly every neighborhood, farm, municipality, and nation have some degree of PFAS soil contamination. However, regulatory or legislative mandates for PFAS monitoring or remediation are rare. Not only is there a lack of monitoring for these dangerous contaminants, but there are also no regulatory safe limits for contamination or community exposure to PFAS. Without monitoring of PFAS contamination levels and benchmarks for remediation, it is inevitable that PFAS will continue to accumulate in our air, water, and soil.

As the world celebrates the importance of healthy soil, what can be done to make the soil safe? Public awareness of the PFAS problem and advocating for PFAS regulations are foundational to creating mandates for PFAS remediation. In addition to remediation, PFAS sources must be reduced or eliminated. Consumers have the power and responsibility to force manufacturers to find and use alternatives to PFAS. Finally, environmental groups and environmentally minded companies working for the removal of PFAS need both moral and financial support. Together we are stronger and we can save our natural resources.