DARPA Ceres remediation program for soil contaminated with explosives and aircraft fuel

Understanding Soil Contamination:

Soil contamination, a consequence of industrial activities, agricultural practices, and improper waste disposal, poses a significant environmental challenge. Common contaminants include petroleum hydrocarbons, pesticides, heavy metals, and explosives such as trinitrotoluene (TNT). Various human activities, including mining, fuel dumping, and fertilizer application, contribute to soil pollution, affecting both terrestrial and aquatic ecosystems.

Health Risks and Environmental Concerns:

Soil contamination presents serious health risks to human populations, primarily through direct contact with contaminated soil or exposure to vapor emissions. Additionally, contamination can lead to the pollution of water sources, exacerbating health hazards. Addressing soil pollution is crucial for safeguarding human health and preserving ecological balance.

Common contaminants like petroleum hydrocarbons, pesticides, and heavy metals threaten human health through direct contact, vapor exposure, and water pollution. Soil remediation offers a solution by purifying contaminated soil, aiming to restore it to a pollution-free state. Traditional methods include soil washing, bioremediation, and thermal desorption, each addressing specific pollutants through chemical or biological processes.

Soil Remediation Techniques:

Soil remediation, aimed at purifying and revitalizing contaminated soil, encompasses several techniques. Traditional methods include soil washing, bioremediation, and thermal desorption. Soil washing employs surfactants and water to remove contaminants, while bioremediation utilizes microorganisms to break down pollutants. Thermal desorption involves heating soil to remove volatile contaminants. These methods, although effective, often require extensive preparation and monitoring, making them laborious and costly for large-scale applications.

Introducing the Ceres Program:

To address the challenges of soil contamination, DARPA launched the Ceres program, focusing on innovative plant-based remediation approaches. UTIA, alongside MIT and PSU, has been awarded a $12 million grant to develop bioengineered solutions for soil contaminated with explosives. Central to the initiative is the bioengineering of switchgrass and associated microbial communities to create a specialized “beacon-cleaner” system.

Bioengineering Solutions:

Genetically modifying switchgrass allows it to serve as a visual indicator of soil contamination, changing color in the presence of explosives like TNT. Concurrently, engineered microbial communities associated with switchgrass actively degrade explosive contaminants, facilitating soil restoration. Safety and sustainability are paramount, with engineered organisms designed to resist explosives’ toxic effects, and stringent measures implemented to prevent unintended environmental consequences.

Timeline, Regulations, and Ethical Considerations

Ceres is a four-and-a-half-year long program divided into two 24-months phases, followed by a final six-month demonstration performed by an independent verification and validation (IV&V) team. Proposers are expected to (1) isolate or assemble functional plant-microbe communities, (2) optimize the communities through biological and ecological engineering into synthetic communities, (3) develop controls so that the synthetic communities can be easily removed post remediation, and (4) generate realistic testbeds that mimic field conditions for synthetic community optimizing and testing.

Ceres aims to engineer modular platforms that demonstrate proof-of-concept capabilities for two specific applications. The “Cleaner” track seeks to develop synthetic plant-root (rhizosphere) microbial communities, where plants, their roots, and microbes act together in a symbiotic way to degrade either TNT or JP-8 down to U.S. Environmental Protection Agency (EPA)-approved levels without dangerous byproducts. The “Beacon” track will develop complementary plant-microbe synthetic communities that provides an overt signal – such as flowers changing color – to indicate that the target contamination has been reduced to similarly safe levels.

Project Duration and Validation:

The Ceres program is a four-and-a-half-year endeavor, divided into distinct phases:

• Two 24-month phases: During this period, researchers will focus on developing the core functionalities of the “cleaner” and “beacon” systems. This involves isolating or assembling functional plant-microbe communities, optimizing them through engineering, and creating realistic testbeds that mimic real-world conditions.
• Final six months: An independent verification and validation (IV&V) team will take over, conducting rigorous testing using soil from diverse U.S. biomes relevant to military bases (Eastern Woodlands, Great Plains, Mediterranean) to ensure the developed systems effectively remediate both explosives and fuel contamination under various environmental conditions.

Compliance and Responsibility:

The project adheres to strict regulations and ethical considerations:

• EPA Compliance: Throughout all phases, researchers must comply with established regulations set forth by the U.S. Environmental Protection Agency (EPA) to ensure the safety and effectiveness of the developed solutions. This includes adhering to guidelines for handling potentially hazardous materials and ensuring the final remediated soil meets EPA’s safety standards.
• Ethical, Legal, and Societal Concerns: The program acknowledges the potential ethical, legal, and societal implications associated with developing and deploying genetically engineered organisms. Therefore, teams working on Ceres are required to collaborate with experts in these domains to proactively address any concerns and ensure responsible development and implementation of the technology.

UTIA Awarded $12 Million Grant for Bioengineered Soil Remediation

Researchers at the University of Tennessee Institute of Agriculture (UTIA) have been awarded a substantial $12 million grant from the Defense Advanced Research Projects Agency (DARPA) to pioneer a groundbreaking solution for remediating soil contaminated with explosives. As part of DARPA’s Ceres program, UTIA will collaborate with experts from the Massachusetts Institute of Technology (MIT) and Pennsylvania State University (PSU) in a four-year project. Their focus will be on bioengineering switchgrass, a native North American plant, and its associated microbial communities to create a specialized “beacon-cleaner” system tailored to address this environmental challenge.

One innovative aspect of the project involves genetically modifying switchgrass to serve as a visual indicator of soil contamination. Through specific genetic alterations, researchers aim to make the plants change color in the presence of explosive trinitrotoluene (TNT), turning red when contaminated and reverting to green once the soil is clean. This approach offers a straightforward and cost-effective means of monitoring the progress of soil remediation efforts.

The other component of the solution entails engineering microbial communities associated with switchgrass to actively degrade explosive contaminants like TNT. These specially designed “cleaner” microbes will possess the genetic tools needed to break down TNT, facilitating the restoration of contaminated ecosystems. Throughout the project, safety and sustainability remain paramount, with the engineered plants and microbes being engineered for increased resistance to explosives’ toxic effects and rigorous safeguards to prevent unintended environmental consequences. This UTIA-led initiative holds great promise for transforming soil remediation practices, offering a sustainable, cost-effective, and visually intuitive approach to addressing lands contaminated with explosives. If successful, this project could set the stage for the development of similar bioengineering strategies to tackle various environmental pollution challenges effectively.

By the end of the program, the IV&V team will perform greenhouse-scale testing using soil from the three major U.S. biomes where U.S. military bases are located – Eastern Woodlands, Great Plains, Mediterranean – for explosive and fuel remediation. Throughout all phases, performers will be expected to conform to U.S. Environmental Protection Agency requirements. Moreover, teams will collaborate with ethical, legal, and societal implications experts to ensure the research addresses any related concerns.

Promising Outcomes and Future Prospects:

Ultimately, the bioremediation platforms developed under Ceres platforms aim to achieve autonomous decontamination and contaminant tracking without the routine addition of power or human intervention.

The UTIA-led initiative holds significant promise for transforming soil remediation practices, offering a sustainable, cost-effective, and visually intuitive approach to addressing lands contaminated with explosives. If successful, this project could pave the way for similar bioengineering strategies to tackle various environmental pollution challenges effectively. Collaborative efforts with an independent verification and validation team will ensure adherence to environmental regulations and ethical considerations, contributing to comprehensive and responsible research practices.

“Biosafety is of utmost importance, and as such a key aspect of this program is building multiple layers of controls for the introduced organisms,” added Sheehan. “That means both controls internal to the organism, using synthetic biology strategies already under development, but also a brand-new class of controls external to the organism using in advances in synthetic ecology.”