Comments on the Remedial Investigation for the Anacostia River Sediment Project
Prepared by Ankita Mandelia
May 14, 2018
These comments are submitted on behalf of the DC Chapter of the Sierra Club, the nation's largest and oldest environmental group with more than 3,500 members in DC. Surface water quality is a priority for DC Sierra Club, and our Clean Water Committee is dedicated to the promotion of planning and programs to remediate and protect our rivers and streams. It is commendable that the District of Columbia is rededicated to the cleanup of the Anacostia River. The Remedial Investigation (RI) document appears to be generally complete; however, our review of the document raises some questions. This set of comments focuses the executive summary and the surface water characterization.
From the Executive Summary
Environmental investigation data collected by the potential environmental cleanup site parties (PECSPs) should be accounted for with caution. Quality assurance project plans should be carefully reviewed to determine that data was collected and analyzed in a thorough and conservative manner.
It would be helpful if the executive summary summarized constituent concentrations in fillet and whole fish with respect to local fish consumption advisories.
How are elevated sediment concentrations in Kingman Lake not associated with toxicity? This statement should be followed by a brief explanation.
If turtles can bioaccumulate chemicals from the Anacostia River sediments, surface water, or prey, how is there no risk to them indicated? The same question applies to birds and mammals. A brief explanation should be stated in the executive summary to justify these statements.
From the Surface Water Characterization
In general, the spatial and temporal scope of the surface water sampling would ideally have been double what was actually conducted. The Phase 1 sampling is sparse, and not enough data was collected to discern trends with any substantial level of uncertainty. The Phase 1 and Phase 2 sampling would also have benefited from additional sampling deeper in the water column than 12 inches. Because Phase 1 sampling was so sparse, ideally, another phase of sampling should have been conducted to better discern trends. An uncertainty analysis would be appropriate in light of the sparse data.
What sampling/analysis was conducted such that sample concentrations could be below the detection limit but above the screening criteria? This justifies explanation either in Tables 8.1 and 8.2, or in the text of section 8.1.1.1.
Section 8.1.1.1.1 should include some speculation as to why PCBs were detected where they were detected.
When presenting scientific background, such as the equilibrium concentration of oxygen in water at sea level, it would be helpful to cite the source of this information.
The efforts to report concentrations of PCBs as congeners (as opposed to Aroclors) are noted and appreciated.
To confirm that sampling results from Phase 1 and Phase 2 complement each other, it would have been helpful to present them both as maps or both as line graphs – but to mix the two presentation methods makes it difficult to compare the two. (Section 8.2)
Section 8.2 features quite a lot of background information, but could use increased focus on data analysis.
Section 8.2.1: The statement regarding the similarities of the box plots between Phase 1, and Events 1 and 3 of Phase 2 is true for PCBs and PAHs, could be interpreted as true for lead, but is not true for arsenic.