Over the past several weeks, I have routed a number of questions to DTSC. Below are the questions and responses:
Question 1: As stated at the last City Council meeting, this offsite contamination will increase with sea level rise, as the salinity of the Bay water will chemically alter the toxics to make them more mobile, to be carried by the existing underground water into the surrounding properties and adjacent marsh and San Francisco Bay.
Summary Response 1: DTSC is unsure what chemical reaction/mechanism is being referred to as it is not specified in the comment. However, it is unlikely that groundwater with increased salinity or saltwater intrusion will result in the migration of contaminants above levels of concern past the biologically active permeable barrier (BAPB) because we expect the BAPB to continue treating metals in groundwater. Also, DTSC will require on-going groundwater monitoring to assess the adequacy of treatment and to make any potential changes needed to assure groundwater is treated to comply with required cleanup standards.
Detailed Response 1: Impacts as a result of sea level rise may be first felt at the biologically active permeable barrier (BAPB) as it is closest to San Francisco Bay. As stated in the draft Feasibility Study/Remedial Action Plan, Section 4.7.2 (Potential Impact of Future Sea Level Rise on the BAPB), increasing sea levels could potentially cause an increase in salinity in the deeper regions of the biologically active permeable barrier (BAPB), as saltwater intrusion increases in the near-shore area. The BAPB creates a reducing condition (sulfate-reducing bacteria helps to remove dissolved metals from the groundwater in the BAPB), resulting in a decrease in the concentration of dissolved metals and volatile organic compounds as groundwater flows through it. Sulfate-reducing bacteria are also found in marine aquatic environments, and thus should acclimate to potential future increases in the salinity of groundwater in the BAPB. Also, an increase in the salinity in the near-shore groundwater may also result in upland groundwater with lower salinity migrating above the higher-density water with elevated salinity (fresher water will pass over saltier water), thus the upland water will pass through the BAPB with limited increases in salinity.
In the short-term, the draft FS/RAP proposes to treat groundwater containing metals and volatile organic compounds. In the longer-term, sea level rise may reduce the groundwater gradient at the Site (so that groundwater would flow slower). This could occur as the groundwater elevation adjacent to San Francisco Bay rises a similar magnitude as the sea level increases, while the groundwater elevation further inland remains relatively unchanged (assuming conditions upland remain similar). The reduced groundwater gradient would tend to slow the groundwater migration rate, potentially providing a longer residence time within the BAPB.
The actual impacts of climate change and potential increases in sea level rise on the performance of the BAPB will be evaluated by monitoring the groundwater within, upgradient and downgradient of the BAPB
Question 2: I want to hear if implementation of the Zeneca cleanup alternative 3a (to leave the vast majority of existing toxics in place on the Zeneca site) could result in the City having to take over the O&M and future remediation costs of that site as well. In particular, I would like the response to address these questions with the possibility in mind that the implemented cleanup alternative at the Zeneca site is found to have failed post-implementation. I would also like confirmation of who is legally responsible for paying for the corrective actions to implement a revised cleanup.
Response 2: Based on the current facts known to DTSC about the Zeneca Site, the City of Richmond has not owned and is not a current owner of the Zeneca Site. DTSC may enforce remediation orders against Responsible Parties. Responsible Parties may include entities who have caused the pollution at the site and those who have ownership interest in a property. At the Marina Bay Site, the City of Richmond has a current ownership interest, therefore has Operation and Maintenance responsibilities to protect the remedy.
Question 3: Also, what would be DTSC’s part in restitution to the City and members of the public harmed by a failed cleanup, especially as the community has more than made it clear for over 13 years now that it wants the full dig-and-haul cleanup (alternative 6) implemented at the Zeneca site?
Response 3: If monitoring or other activities identify an aspect of the cleanup that is not performing as required to prevent exposure or treat contamination, DTSC would require responsible parties to investigate and address the problem to ensure the remedy operates as required by state law.
Question 4: The cover page indicates it was “prepared for Zeneca, Inc.” by Terrphase Engineering, Inc., and page xi indicates that the responsible authors are Andrew Romolo and Wendy Bellah. So, the recommendations in the report are those of Romolo and Bellah? Are you available to take questions from the media about your report and your recommendations? I understand that DTSC has yet to actually adopt a RAP, but does DTSC have any oversight over the preparation of the Draft FS/RAP or endorse any of its content, findings or recommendations? Or, is the Draft FS/RAP simply a product of Zeneca and its consultant, Terraphase, with all credibility falling on Terraphase?
Response 4: DTSC approved the issuance of the Draft Feasibility Study and Remedial Action Plan (FS/RAP) in July 2018. DTSC also approved the FS/RAP’s preferred remedial alternative 3a. DTSC worked with the City of Richmond staff for almost two years to update the FS/RAP to ensure the preferred remedial alternative allowed the site to be used consistent with the City of Richmond’s land use plan after the cleanup. Under state law, DTSC oversees the development of the Draft FS/RAP, which was paid for by Zeneca, Inc. because they are responsible for paying to investigate and cleanup the site. These actions occur subject to DTSC oversight. DTSC uses state and federal laws and guidance to ensure the selected cleanup protects public health and the environment.