Step 1: Preliminary Assessment/Site Investigation
The Preliminary Assessment is the first phase for any potential Superfund project. The EPA analyzes the site for risk to human health and the environment. At the end of this phase, a site may be recommended for site investigation, which is the next phase of Superfund.
In its preliminary assessment of the Gowanus, the EPA found more than a dozen contaminants along the entire length of the canal, including pesticides, metals, Polycyclic Aromatic Hydrocarbons (PAHs), and Polychlorinated Biphenyls (PCBs).
Step 2: National Priorities Listing Process
A Hazard Ranking System (HRS) score is calculated based on the findings of the preliminary assessment and site investigation. Sites with an HRS score of 28.5 or higher are eligible for listing on the National Priorities List (NPL).
The HRS score for the Gowanus Canal was more than 50.
Step 3: Remedial Investigation/Feasibility Study
After a site is added to the National Priorities List, the EPA begins the remedial investigation/feasibility process. Data is collected to determine the site conditions, nature of the waste, and risk to human health and the environment. Using this data, the EPA develops and evaluates alternative Remedial Action (RA)s.
By December 2009, the EPA began a Remedial Investigation (RI) of the Gowanus Canal. As part of the EPA study, the agency collected Sediment, surface water, air, ground and fish samples, as well as samples from Combined Sewer Overflows (CSO) outfalls. The findings of the RI were released in February 2011. (Click here to view the report.) Based on the characteristics identified during the RI, the EPA initiated a Feasibility Study (FS) in the spring of 2011 to develop and evaluate remedial alternatives. Seven cleanup alternatives were identified and analyzed in a report released in December 2011. In December 2012, the EPA followed up the FS with the Proposed Remedial Action Plan (PRAP) for its preferred remediation plan. (Click here to view the PRAP.)
Step 4: Record of Decision
Issued in September 2013, the Record of Decision (ROD) identified the remediation plan for the Gowanus Canal. (See ROD.) The EPA’s selected remedy includes removing contaminated sediment from the canal via dredging, installing a cap, and restoring the 5th Street basin.
Steps 5-9: Looking Forward
After the Record of Decision (ROD), the cleanup must be designed. The Remedial Design (RD) process will include tests and further investigations to determine the best way to implement the ROD and to address the many challenges posed by this remediation. After the final design is approved, the EPA will work with the responsible parties to develop a construction plan, complete construction, remove the site from the National Priorities List, and ultimately, enable reuse of the canal. This process is expected to last many years – with active construction taking place over a six- to 10-year period.