There are approximately 500,000 abandoned mines across the U.S., which pose a considerable, pervasive risk to human health and the environment due to possible exposure to the residuals of heavy metal extraction. Historically, a variety of chemical and biological methods have been used to reduce the bioavailability of the metals at abandoned mine sites. Biochar is emerging as a novel soil amendment for agriculture and environmental applications that can be used to increase soil carbon, adjust soil pH, supply and retain nutrients, reduce heavy metal bioavailability, improve soil water holding and infiltration, sequester carbon, and provide refugia for soil organisms.

Biochar is a charcoal-like, carbon-rich, porous byproduct of thermal pyrolysis or gasification. What makes biochar unique is that its properties are tunable, meaning that they can be manipulated or adjusted to optimize the benefits of using it as a soil amendment. It has the potential to complex and immobilize heavy metals to reduce bioavailability in situ. Simultaneously, biochar can improve soil conditions for plant growth and promote the establishment of a soil-stabilizing native plant community to reduce offsite movement of metal-laden waste materials.

Because biochar properties depend upon feedstock selection, pyrolysis production conditions, and the activation procedures used, they can be designed to meet specific remediation needs and specific soil remediation situations. However, techniques are needed to optimally match biochar characteristics with metals contaminated soils to effectively reduce metal bioavailability Ongoing research at Formosa Mine in Oregon and other sites to immobilize heavy metals from tailings and revegetate the soil will be presented."

Presenter:

Mark G. Johnson, Ph.D., U.S. EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Western Ecology Division (johnson.markg@epa.gov or 541-754-4696)
Mark Johnson has a Ph.D. in Soil Chemistry from Cornell University (1985) and has worked at EPA since 1985. The goal of Dr. Johnson’s work as an EPA Research Soil Scientist is to conduct world-class, state-of-the-science research in support of the mission of the EPA. His research at EPA has covered a wide range of topics including the effects of acid rain on soil, managing soil carbon, understanding the belowground effects of climate change, nanoparticles in the environment, and biochar as a soil amendment. He is the author/co-author of more than 100 peer-reviewed articles and reports.

In 2009, EPA launched an initiative to explore the use of bio-energy to combat greenhouse gas emissions from fossil fuels and as a potentially sustainable and renewable source of energy. To support this Agency need Dr. Johnson began investigating pyrolysis (heating biomass in the absence of oxygen), using waste biomass, as one such energy source and as a potential source of very stable carbon (i.e., biochar) that could be used for carbon sequestration. This led to research on producing and characterizing biochar to improve the fertility and water holding capacity of well-used, sandy, coastal plain soils in the southeastern U.S. that have been in agriculture for more than 150 years.

Dr. Johnson’s current biochar research is on designing and evaluating biochars for use as a soil amendment for improving soil quality, preventing water pollution, sequestering carbon and for soil restoration, revitalization and remediation. He also conducts research on the effects, fate and movement of manufactured nanoparticles in the environment.

Moderators:

Michele Mahoney, U.S. EPA Technology Innovation and Field Services Division (mahoney.michele@epa.gov or 703-603-9057)
Michele Mahoney is a Soil Scientist working on issues related to remediation and reuse of contaminated sites within EPA's Superfund program. In order to support practitioners, she researches and reports on knowledge related to treatment technologies for mining sites, use of soil amendments for remediation and redevelopment/reuse, ecological revitalization, ecosystem services, phytotechnologies, and urban gardening. Michele develops and delivers training for the world-renown EPA Clean-Up Information Network (www.cluin.org), particularly a Mining Webinar Series, and topics related to Superfund Redevelopment, Ecological Revitalization, Ecosystem Services, and Phytotechnologies. She also creates and manages content development for the EcoTools and Mining pages on CLU-IN.org.

Michele has worked with EPA for over 20 years. Prior to her current responsibilities, Michele served the Agency as the lead for food waste composting issues and as an environmental fate and ecological risk assessor for pesticide registration. Michele also has experience as a Contractor for EPA and a Laboratory and Field Researcher.

Michele earned a M.S. in Soil Science from the Washington State University, and a B.S. in Agronomy & Environmental Science from Delaware Valley University.

Jean Balent, U.S. EPA Technology Innovation and Field Services Division (balent.jean@epa.gov or 202-566-0832)
Ms Balent is on the staff of the EPA's Technology Innovation and Field Services Division where she has worked to collect and disseminate hazardous waste remediation and characterization information since 2003. Ms Balent manages the Clean Up Information Network website and actively supports online communication and collaboration resources available to EPA. She formerly worked with the US Army Corps of Engineers Environmental Engineering Division in the Buffalo District. Ms Balent was also a member of the SUNY-Buffalo Groundwater Research Group where she constructed and tested large scale models of groundwater flow. Ms Balent has also conducted research relating to the Great Lakes, environmental remediation, and brownfields re-development. She holds a Bachelor's degree in environmental engineering from SUNY-Buffalo and a Master's degree in Information Technology from AIU.

Webinar Slides and References:

• 1st Slide Presentation for Mark G. Johnson, Ph.D. U.S. EPA, ORD, NHEERL, WED (5.11MB/PDF)
• 2nd Slide Presentation for Mark G. Johnson, Ph.D. U.S. EPA, ORD, NHEERL, WED (10.9MB/PDF)
• 3rd Slide Presentation for Mark G. Johnson, Ph.D. U.S. EPA, ORD, NHEERL, WED (4.05MB/PDF)

Webinar Slides and References:

• 1st Slide Presentation for Mark G. Johnson, Ph.D. U.S. EPA, ORD, NHEERL, WED (5.11MB/PDF)
• 2nd Slide Presentation for Mark G. Johnson, Ph.D. U.S. EPA, ORD, NHEERL, WED (10.9MB/PDF)
• 3rd Slide Presentation for Mark G. Johnson, Ph.D. U.S. EPA, ORD, NHEERL, WED (4.05MB/PDF)

Additional Resources:

• SEM Images of Douglas-fir Wood Feedstock and Biochar Produced at Different Pyrolysis Temperatures (1MB/1pg/PDF)