Multiple changes to the cleanup plan for the Lower Duwamish Waterway Superfund Site have been proposed since early 2021. We are helping our community partners interpret the science driving the changes and their likely repercussions.
Since early 2021, our community partners have been concerned about proposed changes to the plan for the cleanup of the Duwamish River that was finalized in 2014 by the U.S. Environmental Protection Agency (EPA) in their Record of Decision (ROD). As our partners work to understand the implications of the proposed changes, the UW SRP Community Engagement and Research Translation Cores have been providing technical support to help interpret the science underlying the proposed actions.
The first proposed change to be announced by EPA early in 2021 was an Explanation of Significant Difference resulting from a 2017 update to the previously existing toxicological profile for Benzo[a]pyrene (BaP) and carcinogenic polycyclic aromatic hydrocarbons (cPAHs). The new degree of toxicity assigned to these chemicals resulted in a proposed change to increase the levels of allowable carcinogenic polycyclic aromatic hydrocarbons (cPAHs) in the river to seven times the previous limits.
In order to better understand the changes to the toxicological profile for BaP, the UW SRP met with Dr. Diana Rohlman of the Oregon State University (OSU) SRP, which specializes in PAHs and had assisted community groups who work to promote environmental justice near the Portland Harbor Superfund Site. Dr. Rohlman explained that the OSU SRP research group found it problematic that BaP is used as a reference PAH, meaning that the toxicities of other cPAHs are determined relative to BaP. Under this system, changes to the toxicity assigned to BaP are reflected in all other cPAHs. The OSU SRP suggests that the toxicities of each cPAH should instead be evaluated individually.
Next, the UW SRP convened scientific experts who had participated in EPA's most recent review of BaP's toxicity to discuss the reasoning behind which papers were included. Both experts stated that the review had been in accordance with standard EPA protocols. However, as they recalled, their panel of academic advisors had recommended including more than just the two studies (out of 15) that were ultimately used. The two studies included indicated that the toxicity for BaP was lower than the previous standard while most of the other studies considered indicated that it was higher.
The UW SRP CEC and RTC shared these two concerns with our community partners to support their engagement with Region 10 EPA.
In a similar way, the UW SRP has supported community partners by helping to interpret the proposed plan for cleanup of the East Waterway- a Superfund Site that is treated as distinct from the Lower Duwamish Waterway Superfund Site although the two sites are part of the same river. The cleanup plans depend in part on the definition of background levels of pollution, which differs between plans for the two sites. As a result, the proposed cleanup plans for the East Waterway are much less protective of human and ecological health.
Finally, it has been uncovered that sediments at a site known as Jorgenson Forge were not cleaned up to the standards outlined in the 2014 ROD for the Lower Duwamish Waterway. EPA is now putting forth three proposed plans for further cleanup- none of which are as strict as the original.
In each of these cases, UW SRP has helped to interpret the implications of the proposed changes to levels of contaminants remaining in the river and to human health, playing an important role for our community partners who represent environmental justice communities likely to be impacted by the changes.