Get ready for a deep dive into the report that tries to answer the question, “Did cleanup work?” for Hanford waste sites that were cleaned up under the Superfund law, or CERCLA; the U.S. EPA's CERCLA 5-Year Review!
On September 30, 2021, the U.S. Department of Energy released a draft of Hanford's fifth CERCLA 5-year Review. CERCLA, the Comprehensive Environmental Response Compensation and Liability Act, more commonly known as Superfund, is one of the laws that applies to Hanford cleanup. The Hanford site has four sites that are designated as “Superfund sites.”
What does the CERCLA 5-year Review actually do? Hanford cleanup is a large, unwieldy mission. One way to assess if contamination was adequately removed and/or contained is by checking up on the different waste areas around the site. Each waste site and type of waste requires a special method or technique to remove contaminants. Removing contaminants from groundwater isn't the same process as removing contaminants from a trench in the ground. The CERCLA 5-year Review examines each unique cleanup solution and determines whether the solution protects human health and the environment.
Every Superfund site is under the authority of the U.S. Environmental Protection Agency and a CERCLA 5-year Review is conducted at each site. Hanford is a federal facility overseen by USDOE. Therefore, USDOE conducts the CERCLA 5-year review, prepares the report and submits the report to U.S. EPA for review and comment. USDOE is responsible for ensuring that the recommendations received from U.S. EPA and the follow-up actions in the report are completed. The draft CERCLA 5-year Review is also shared with stakeholders, such as WA Department of Ecology, Tribal Nations, and the Hanford Advisory Board. These stakeholders are invited to comment on the draft review. USDOE must also notify the local community that they are preparing to conduct a 5-year Review by posting a notice in a local newspaper or announcing it on the radio.
Under the Superfund site distinction, Hanford is divided into four different areas called National Priority List sites (NPL) or Superfund sites. Three NPL sites are in the River Corridor area: the 100 Area, 300 Area and 1100 Area, and one NPL site is in the Central Plateau: the 200 Area. Because Hanford is so large, the four NPL sites are further broken down into “operable units” that address a specific area onsite. Thirty operable units are included in the CERCLA 5-year review process, but this number will grow once cleanup solutions are decided upon for additional areas of the Hanford site. The term “operable unit” isn’t very descriptive or intuitive. To make it easier to understand, operable units at Hanford can include: soil, debris, ditches, landfills, tanks, pipelines, structures, and areas of groundwater. The area that includes the operable unit, such as groundwater, is outlined on a map in order to avoid confusion between one area and another.
This map shows the various groundwater operable units at the Hanford site. The operable units are labeled “Groundwater Interest Areas” in the map’s legend.
When USDOE conducts a CERCLA 5-year review, they read technical documents, review and analyze data, inspect each operable unit site, may conduct interviews and finally determine how protective the cleanup solution is. When USDOE is reviewing the information available for each operable unit, it must keep in mind three questions:
Is the cleanup remedy working? For example, is pump and treat still working to treat groundwater and remove contaminants?
Are exposure assumptions still valid? When the cleanup remedy was first chosen, there were certain assumptions made about cleanup levels, toxicity data, etc. Are these assumptions still valid or has something changed over the years?
Is there anything else to consider? For example, a flood, earthquake or wildfire could potentially affect the success of a cleanup remedy.
You may ask, when will the CERCLA 5-year Review process ever end? In general, the goal of cleanup at a Superfund site is to reach a point where the levels of hazardous substances and contaminants are sufficiently lowered in order to allow for "unlimited use and unrestricted exposure". If the site is so thoroughly cleaned up that people can freely and safely return, then the CERCLA 5-year Review process is no longer needed. For the Hanford site, this will be hundreds of years down the road.
Keep an eye out for Hanford's fifth final CERCLA 5-year Review on May 4, 2022.
This material is funded through a Public Participation Grant from the Washington State Department of Ecology. The content was reviewed for grant consistency, but is not necessarily endorsed by the agency.