Sample Design & Cleanup Verification | Projects

DOE’s cleanup actions in the River Corridor were initiated in 1994 under the Comprehensive Environmental Response, Compensation and Liability Act of 1981 (CERCLA). The regulatory authorization for waste site cleanup actions at source operable units (OUs) in the River Corridor consists of interim action records of decision (IARODs). The selected remedy is waste removal (excavation) and onsite disposal. DOE’s River Corridor Closure Contract (RCCC), awarded to Washington Closure Hanford (WCH) in 2005, focuses on source operable units and has allowed cleanup actions to continue in the 100 and 300 Areas with completion by 2015.

The IARODs set forth remedial action objectives (RAOs) and remedial action goals (RAGs). RAOs define the extent to which waste sites require cleanup to protect human health and the environment. Generally speaking, verification that waste site cleanup efforts have achieved the RAOs is accomplished through sampling of the remediated waste site for contaminants per a sampling and analysis plan that is jointly approved by DOE and the lead regulatory agency (EPA or Ecology). Cleanup verification packages (CVPs) are then prepared to document the verification of interim remedial action at a waste site. The data collected for the cleanup verification reports will also support a quantitative baseline risk assessment for the leading to final cleanup decisions and eventual CERCLA closeout.

CVPs are prepared for individual waste sites that have been remediated, or a group of remediated waste sites, as needed. Each report includes a description of the waste site history, the current waste site condition, the basis for reclassifying a site as “closed” or “interim closed,” and verification sampling results. A description of the remediation activities, the logic for determining the contaminants of concern for verification sampling, and supporting calculations are also included in the CVPs. Regulatory agency review and approval of each CVP is part of reclassification of the waste site from “accepted” to “interim closed out.” Each waste site decision is documented on a Waste Site Reclassification Form, which is jointly approved by DOE and the lead regulatory agency (EPA or Ecology).

The River Corridor also includes a large number of miscellaneous waste disposal sites, burn pits, debris piles, and unplanned releases collectively referred to as “remaining sites.” Some remaining sites are designated for remediation in the IARODs and, after cleanup, are closed out via a Waste Site Reclassification Form with a supporting “Remaining Sites Verification Package” (RSVP) approved by DOE and the lead regulatory agency. Similar to the CVPs, each RSVP includes the waste site history, results of previous sampling (if any), a description of the remediation activities, cleanup verification sampling results, the basis for reclassification and supporting calculations, and the current waste site condition.

The remaining sites have widely varying characteristics and waste disposal histories. Consequently, site-specific cleanup verification sampling strategies to demonstrate compliance with the RAOs, called Work Instructions , are typically developed to help ensure proper characterization. The Work Instruction for a given site undergoes review, revision as needed, and approval by DOE and the lead regulatory agency, prior to implementation. If the resulting verification sampling shows that the RAOs have not been met, then further remedial action is performed followed by additional verification sampling. If evaluation of the cleanup verification samples shows that the RAOs for a remaining site are met, compliance is documented in an RSVP.

Other remaining sites need further evaluation to determine whether remediation is required to meet RAOs. Such sites are examined individually per a decision-making process that includes an evaluation of process knowledge, site history, and previous sampling data. If existing data are insufficient to determine whether remediation is required, then confirmation sampling is conducted at the site per an approved Work Instruction. Confirmation sampling results provide additional data to support decision making. Based on confirmation sampling data, the site is either 1) identified for remediation or 2) reclassified as “no action” in an approved WSRF and RSVP. Sites identified for remediation by confirmatory sampling must be reclassified as “interim closed out” via an approved WSRF and RSVP following remediation.