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Subscribe to this list via RSS Blog posts tagged in Superfund

Posted by on in Centers of Excellence
Posted on behalf of the author Paul Scott

Environmental Protection Agency (EPA) Administrator Scott Pruitt on May 10, 2017 issued a memorandum revising the existing delegations of authority related to the approval of proposed remedies at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), or “Superfund” sites. In the memorandum, EPA Administrator Pruitt reserved his authority to make the remedy selection at CERCLA cleanup sites whose Record of Decision (ROD) had a proposed cleanup cost exceeding $50 million.   In the past, remedy selection decisions at these sites were performed by the Assistant Administrator for the Office of Land and Emergency Management and the Regional Administrators.  The stated purpose of Administrator Pruitt's delegation of this authority to his office for these sites was to improve the remedy selection process and to involve the Administrator and his office in the remedy selection process more directly.

This change in remedy selection authority will have a direct impact on contaminated sediment sites where the proposed remedy is often in the hundreds of millions of dollars let alone greater than 50 million dollars.  For most of the major contaminated sediment Superfund sites, the selected remedy will have to be approved by the Administrator instead of by a Regional Administrator or Assistant Administrator for the Office of Land and Emergency Management.  For perspective, the proposed costs for the remedies for the following sediment sites from their respective RODs:

  • Hudson River: $460 million 
  • Passaic River: $1.38 billion 
  • Fox River: $390 million
  • Lower Duwamish River: $342 million
  • Portland Harbor: $1.05 billion

The announcement and a link to the memo are located on the EPA website here.
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Posted by on in Health & Environmental Risk Assessment
Posted on behalf of the author, Michael Ierardi

Although asbestos has not been mined in the United States since 2002, the U.S. EPA is currently managing at least five active Superfund sites associated with impacted soil at former asbestos manufacturing facilities. Activity-based sampling at the BoRit site in Ambler, Pennsylvania has shown that asbestos fibers could potentially be released during remediation activities resulting in residential airborne concentrations of up to 0.13 fibers/cc. Therefore, in situ remediation of asbestos-impacted soil has been an active area of soil science research.

While the exact biological mechanism(s) by which asbestos exerts toxic effects is unknown, some studies have found that fiber mineral iron content may be an important factor contributing to asbestos fiber toxicity. In fact, crocidolite—one of the most biologically harmful types of asbestos—can contain up to 29% iron within its crystalline structure. Once inside the body, the iron in asbestos can become toxic, generating hydroxyl radicals, which are highly reactive compounds that are responsible for DNA damage. Yet, recent research points to promising species of soil fungi that may be able to attenuate asbestos toxicity while in the environment.

Researchers in Italy have collectively studied 12 different species of fungi that grow and thrive in serpentine-rich (i.e., asbestos-containing) soils, which are typically inhospitable environments. They found that over half of the sampled species produced iron-chelating compounds called siderophores in the presence of asbestos fibers, effectively encapsulating the fibers within the fungi’s hyphae matrix. The researchers noted that numerous organisms have developed these types of mechanisms in order to collect iron from the mineral-poor soils in which they grow. They concluded that these fungi’s iron-scavenging techniques could prove to be extremely useful in the bioremediation of asbestos-containing soils.

For more information, please visit the link below:

http://pubs.acs.org/doi/pdf/10.1021/es060881v
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