In a study published in the Proceedings of the National Academy of Sciences, lead author Jake T. Thompson and colleagues outline a solution to agricultural soil pollution. Millions of hectares of cropland worldwide are contaminated by synthetic per- and polyfluoroalkyl substances, known as forever chemicals, due to decades of biosolids application. These toxic compounds accumulate in soil, migrate into groundwater, and enter the food supply, posing severe health risks. Traditional cleanup methods, such as excavation or high-temperature soil burning, are extremely costly, destroy topsoil, and release massive amounts of greenhouse gases.

The research team presents an integrated strategy combining phytoremediationThis is a technique that uses plants to clean up contaminated soil or water. Biochar can enhance phytoremediation by improving soil conditions and promoting plant growth, allowing plants to absorb and break down pollutants more effectively.   More, soil acidity management, and biochar conversion. By applying crushed alkaline rocks like basalt to farmland, managers can raise soil pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More. This adjustment increases the mobility and bioavailability of toxic compounds like perfluorooctane sulfonate, enabling crops such as hemp and red fescue to absorb contaminants rapidly. Stochastic modeling demonstrates that soil pH management accelerates contaminant uptake, cutting remediation timelines by more than a decade under typical field conditions.

Harvesting crop biomass removes toxic chemicals from the field. The harvested plants then undergo high-temperature pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More, breaking down synthetic chemical bonds and destroying trapped pollutants to produce contaminant-free biochar. Reapplying this biochar to soil creates a protective matrix that binds residual chemicals, reducing leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More into groundwater by over ninety-five percent. This dual extraction and immobilization approach stabilizes heavily polluted farmland while keeping food chains safe.

Beyond environmental cleanup, the framework delivers significant climate benefits. Simulations across one million hectares of impacted United States cropland show a carbon dioxide removal potential of eleven million metric tons annually. Biochar production contributes nearly ten million tons of durable carbon storage, while rock weathering provides the remainder. Over twenty years, the approach can remove over two hundred million tons of carbon dioxide, helping achieve national climate targets while avoiding hundreds of millions of tons of emissions from soil excavation.

The economic analysis highlights substantial savings compared to traditional technologies. Conventional excavation costs up to one point six million dollars per hectare, creating prohibitive financial burdens. Without carbon offsets, the proposed framework costs forty-two hundred dollars per hectare annually. Incorporating carbon removal credits at a social carbon price of one hundred ninety dollars per ton reduces the net cost to fourteen hundred sixty dollars per hectare. This strategy provides farmers with an affordable pathway to restore land independently.

Source: Thompson, J. T., Dobson, M., Suhrhoff, T. J., Kanzaki, Y., Kent, C., Bryce, L., Milliken, E., Reinhard, C. T., Yao, Y., & Planavsky, N. (2026). Integrated thermal and phytoremediation of agricultural soils impacted by PFAS. Proceedings of the National Academy of Sciences, 123(30), e2600786123.