Monthly Meeting Summary Thursday, February 8, 2018

Transcription

1 Monthly Meeting Summary This meeting summary was prepared by the CAG Facilitator, to capture the key points, questions, and comments made at the CAG meeting. It is not verbatim, and should not be used as a source of official technical information, individual or agency quotes, or CAG statements or positions. Documents and presentation materials referenced in this summary are posted to ourpassic.org. Lower 8.3 Mile Alice Yeh provided this update. The project is in the remedial design phase to determine details of how to conduct the cleanup. A comprehensive sampling program is being conducted by Tetratech. The actual sampling was completed at the end of January at 804 sediment sampling locations each collecting several cores that were split and sent for analysis. Over next few months, labs will run tests, data will be validated and then be available for use. EPA will invite Tetratech back to a future CAG meeting to explain the data in the late spring or early summer. Sampling went smoothly up until the cold weather of January, when the frozen river and docks made it difficult, but we persevered and continued to collect samples as much as possible. They really demonstrated a commitment to getting the work done to stay on schedule. The work plan does say that we expected 958 sampling locations, the lower number is mostly due to the areas where utilities cross the Passaic as we could not drill too close to those pipes and cables. It was a problem for sampling and will also be a problem for dredging. We will look at this during the design phase to determine how to deal with this during construction. We are now moving to water sampling, biota and habitat studies. We expect to approve those workplans later this month and post them on ourpassaic.org. We will describe those processes at a future CAG meeting. Conceptual Site Model Jen LaPoma presented the conceptual site model. We want to give you an overview for the site, the different components of the site include the lower 8 miles, upper 9 miles (up to the Dundee Dam). EPA conducted early sampling for the remedial investigation/feasibility study (RI/FS), and the CPG took over in 2007 and sampled through 2014, Since then have been working on the RI report.

2 Jen presented a visual depiction of the conceptual site model, an important tool used in the Superfund process to look at sources, pathways, and receptors to support site decisions. CAG: Why is the mean concentration in upper 9 miles higher than overall? EPA It is skewed by the River Mile 10.9 data as there is a very high concentration of sample locations with the removal area at We have learned some key points from the sampling. Concentrations are largely driven by sediment type and deposition and erosion history. The highest concentrations are generally found in fine-grained sediments. The chart in the presentation shows a much lower percentage of fines in the samples from the upper 9 miles of the river, which in turn have lower concentrations of contaminants. CAG: Quite a few of the locations of the finer particles are near parks. CAG: Where do you start measuring the river? The Army Corps and EPA don t have the same starting point for the 0 mile mark. EPA: We are using EPA s starting point. The Corps and EPA starts are about 0.3 miles difference, so it would not make much different in scale. Contaminants remain at high concentrations because of legacy sources. The highest concentrations are found at the inner bends of the river where the fine materials concentrate. We have conducted bathymetry surveys, and now have a fairly good understanding of the erosional and depositional nature of the river. Higher salinity water moves into the river from Newark Bay. This moves below the fresh water flowing from upstream and pushes contaminants upstream. Contaminated sediments may serve as a source to the water column. The human health risk assessment Is driven largely by the ingestion of dioxin and PCBs through eating fish and crabs. The Reasonable Maximum Exposure is a risk of 4x10-3 which is above EPA s acceptable risk range of 1x10-4 to 1x10-6. The noncancer hazard index ranking is 200 which exceeds the EPA target of 1. 2

3 Proposal for an Interim Remedy for the Upper Nine Miles Michael Sivak presented this information. EPA created an operable unit (OU) for the lower 8 miles because that is where the highest levels of contamination were found, and this allowed us to accelerate this part of the cleanup. We also identified a high concentration source area at River Mile 10.9 and decided to remove that under a quick removal action. It is a very complicated water system to understand and we are still learning about how the system behaves and the full nature and extent of contamination in the upper nine miles. The Remedial investigation (RI) is a very important part of the Superfund process. It helps us to understand where the contamination is located and how it moves throughout the system. When contamination moves around and becomes available to environmental and human receptors, we consider that a source of contamination. Our goal is to remove these sources and help to control the risks. We will discuss two key questions: Does an Interim action for the upper nine miles make sense? What key concepts from the CPG proposal make sense to consider in creating additional alternatives for interim actions? CAG: Is the concentration in the upper nine miles significantly lower than Newark Bay? EPA Not so, dioxin and PCBs are the biggest risk drivers and upper nine has significantly higher concentrations than the bay, other contaminants are about the same. Why EPA is considering an interim action: could get source area contamination removed faster should expedite risk reduction by minimizing ongoing threats to people s health and the environment should be consistent with the final remedy builds in monitoring after each phase to determine effectiveness allows for additional cleanup as necessary. CAG: what typically triggers an interim action and what does EPA consider? EPA: Can come from internal conversations to drive us to get quicker reductions in risk. As soon as we saw the data for the removal at RM10.9 we knew that was a source, and the same with the lower 8 miles. Now that we are looking at the upper nine we see concentrations in some locations at a higher level, largely concentrated in fine materials. As we have been reviewing the data and writing the RI, we have started to understand what the data is telling us and that is why we are thinking about can we get it out sooner. CAG: Why an interim and not just do a final remedy? 3

4 EPA: We don t have all of our models completed yet, they will take quite a bit more time as this is a complex system with lots of different types of sediments. Models can take months to run and there are a number of different models that need to be run. We do think we have enough information to conduct an interim action because we do understand where a lot of these contaminants are located at this point. EPA s 2005 Sediment Guidance says that early or interim actions must be followed by monitoring before deciding on a final remedy. EPA uses adaptive management at complex sediments sites to test hypotheses and evaluate assumptions as new information is gathered. We will phase in remedy selection where fate and transport is not well understood and consider separating management of source areas from other areas. CPG s proposed Interim Action Approach includes the following actions: Remove source material in the upper nine miles quickly Identify material for removal based on the conceptual site model of how the contamination in the river moves Coordinate remedial action activities with the lower 8.3 miles for economies of scale Begin post action monitoring early. Remedial Action Level (RAL): A chemical-specific sediment concentrations that is used to delineate areas where active remedial measures (e.g., dredging or capping) will be undertaken under a given remedial alternative. This is the level that will determine what contamination gets removed from the river. Surface Weighted Average Concentration (SWAC): The measure of the average surface concentration of the top six inches of a given area of sediment. This is how we will calculate what is left. Removing high concentration areas will help the river to recover by preventing recontamination and allow cleaner sediments to redeposit. Steps in the proposed interim remedial process would be: 1) Record of Decision (ROD) 1 For the upper nine miles, address sediment posing the greatest risks or preventing the rest of the river from recovering 2,3,7,8-TCDD Sediment SWAC reduced by ~90% following interim action Total PCBs reduced below background 2) Then, monitor fish, crab, water and sediment to confirm contamination levels in the river are going down 3) ROD 2 Conduct additional removal if needed or set final cleanup levels if risks calculated for new conditions are within acceptable levels. CAG: How would the 90% be determined? 4

5 EPA: Looked at data based on sampling available and would use a RAL that would result in a 90% removal of the contamination. More sampling would be conducted before the final decision of a RAL. CAG: Would the models be assessed as part of the final ROD? EPA: We will look at the samples collected in the upper 9 miles during the RI and more sampling before the first ROD which we hope to fill in a lot of the gaps and refine the modelling. This would be used post remedy to look at how actions were impacting the river. CAG: What would be the extent of pre-design investigation sampling, would it go beyond what is currently known as hotspots? EPA: Yes, it would look at the whole river and could result in expanded areas for removal. CPG s proposed approach: Phased approach to address the upper nine miles Proposed Remedial Action Level ( RAL ) of 300 ppt (ng/kg) 2,3,7,8-TCDD and 1 ppm (mg/kg) of Total PCBs Dredge and cap approximately 80 acres from RM 8.3 to RM 14.7 Remedial footprint will be reassessed after a Pre-Design Investigation Remedial Design will include refined modeling projections for sediment and tissue recovery Performance Monitoring will be used to determine if additional actions are needed to achieve acceptable risk levels as part of a final Record of Decision (ROD). CAG: How did you come up with 300 ppt number? EPA: When you look at surface sediments recently deposited, they are in the ballpark of 300 ppt, and the particles moving around the system in the surface water range from 200 to 400 ppt. If you remove everything above 300, it would dramatically reduce the overall recontamination levels. CAG: When would this work actually be able to take place? EPA: Currently would not get to a ROD until 2027 and begin construction in Under the expedited approach we would have a ROD in 2020 and finished with the remedial action in EPA still considering: Single RAL vs. spatially varying RALs Impact of alternate RALs on SWACs and risk Ecological risk estimates need to be revised using species/location-specific exposure concentrations Performance monitoring plan must be robust and agreed upon before the start of remedy implementation. 5

6 The CAG and other stakeholders invited to present on the morning of the March 1 st meeting of the EPA s Contaminated Sediment Technical Advisory Group (CSTAG). The purpose of CSTAG is: To help appropriately investigate and manage EPA sites in accordance with the 2005 Contaminated Sediment Remediation Guidance for Hazardous Waste Sites, and other relevant EPA guidance and policies appropriate for sediment sites. To encourage the use of state-of-the-science tools and methods to complete an adequate and timely characterization of the nature and extent of contamination and to help ensure the selection of a cost-effective remedy that will control sources and achieve long-term risk reduction while minimizing short-term impacts. To encourage national consistency in the characterization and management of sediment sites by providing a forum for exchange of technical information among the CSTAG members. After the CSTAG meeting, EPA will be available to continue to answer questions and will participate in further discussion at the March 8 CAG meeting. CSTAG reviews take several months to complete. Once we get feedback, we will share with the CAG. The CPG proposal may be further assessed as part of a full Feasibility Study. EPA suggests enhanced outreach to communities along the upper nine miles of the river. CAG: You can get a lot of valuable information with a good model for the upper nine miles, are you considering a model for the upper nine miles to help pick the RAL? EPA: We do not have a good data set for historical concentrations, so we have to use assumptions and this does not give us as good a result as for the lower 8 where we had better data. We also don t have high enough concentration of data to give us fine results. We hope the pre-investigation data will help us Does the CAG think this makes sense in general? CAG: Do we feel confident that the data that is driving this potential decision is giving us enough confidence to make this decision. Are there hotspots? EPA: In the lower 8, we saw that everywhere we looked, we had fines. In the upper 9 miles, we are seeing a very different type of system and there are not fines everywhere so we have some confidence that we are going to find the contamination where we find the fines. In any interim remedy we will still have to go back and refine our understanding and confirm results. 6

7 CAG: What is the process and timing of EPA s analysis of the interim action? EPA: Looking for feedback from the CSTAG and then develop alternatives, perhaps considering different RALs. This would likely happen over the summer of CAG: Why is this different than from when this was proposed for the lower 8? EPA: The sediments in the upper nine are very different from the lower 8. A hot spot approach in the lower 8 just wouldn t work. But it does potentially work in the upper 9. CAG: Are you really getting it out, not really as you are only removing surface sediments and capping? EPA: Yes, we are removing contaminants in the biologically active zone that would be susceptible for recontamination. CAG: Will this be a true ROD with a feasibility study? EPA: Yes, full Superfund process leading to an interim ROD in 2020/2021. The meeting adjourned at 8:10 PM 7