Pikul, Gretchen M (DEC) <This email address is being protected from spambots. You need JavaScript enabled to view it.> Jun 12 at 2:15 PM
Attachments: Hawk Inlet TMDL Public Notice Response to Comments Final.pdf
Good afternoon,
The U.S. Environmental Protection Agency has approved the Total Maximum Daily Load (TMDL) for the waters of Hawk Inlet. The TMDL summarizes available water quality data in Hawk Inlet, and provides recommendations to address metal-contaminated marine sediments at the Greens Creek Mine Loading Dock and an area in the north end of Hawk Inlet. The TMDL can be found at http://dec.alaska.gov/water/tmdl/approvedtmdls.htm. Thank you to those who provided comments, as well as additional data for the Hawk Inlet area. Your input helped make this a more comprehensive and useful document. The agency Response to Comments document is attached. Please share this plan with others who may have interest.
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Gretchen Pikul Environmental Program Specialist Alaska Dept. of Environmental Conservation Division of Water, Non-Point Source Section http://www.dec.alaska.gov/water/wqsar/index.htm |
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The final document can be found at: http://dec.alaska.gov/water/tmdl/approvedtmdls.htm EPA made responses to comments by Tom Price, Electronic Review for the Environment, Inc., identified as commenter #21 below:
5. General: Editorial (Incorporates individual comments from comment numbers 4, 6, 7, 19, and 21.) Comment Summary: There were 42 editorial comments submitted regarding issues related to report format, typographical errors, grammar, and figure legibility.
Response: All of these editorial comments have been addressed in the TMDL report, unless it was determined that the report need not be changed. Changes to the TMDL have been made based on these comments
7. General: TMDL Process (Incorporates individual comments from comment number 21.) Comment Summary: There is no signature block on the document. The Seasonal Variation and Critical Conditions section should be deleted because the information is inadequately supported and contradictory.
Response: A signed DEC transmittal letter and a signed EPA approval letter will accompany the final TMDL. The statute and regulations require that a TMDL be established with consideration of seasonal variations. The TMDL must describe the method chosen for including seasonal variations. (CWA §303(d)(1)(C), 40 C.F.R. §130.7(c)(1) ). Of the required elements of TMDLs, Alaska must consider seasonal variation to ensure that a waterbody under a TMDL will meet water quality standards during all seasons of the year (40 CFR 130.33(b)(8)). Additionally, TMDLs must take into account critical conditions for steam flow, loading, and water quality parameters as part of the analysis of loading capacity. (40 C.F.R. §130.7(c)(1)). TMDLs should define applicable critical conditions and describe their approach to estimating both point and nonpoint source loadings under such critical conditions.(Guidelines for Reviewing TMDLs under Existing Regulations issued in 1992, US EPA, May 20, 2002). While the Seasonal Variation and Critical Conditions section must remain in the TMDL report, the report does state that there is no statistical significance to seasonality in the data; therefore, the numeric targets apply at all times (year round). TMDLs use the best available information and can be revised if new information impacting the TMDL becomes available. No changes have been made to the TMDL based on these comments.
16.Implementation: Clean Up Spill (Incorporates individual comments from comment numbers 16 and 21.) Comment Summary: All spilled debris should be cleaned up.
Response: Kennecott Greens Mining Company (Kennecott) attempted to clean up all spilled concentrate in 1994. Divers used suction dredges to remove approximately 550 cubic yards of material from the spill site over the course of 20 days. The work was slowed by large amounts of debris from historic cannery operations in Hawk Inlet. According to the final report submitted by Kennecott on the spill clean-up (Ship Loader Dredging Project, 1995), both sediment sampling and visual assessments of the site indicated that the concentrate had been removed. As stated in the report: The Dredge and Spoils sample…indicates a fairly even mix of lead and zinc with similar values to the shiploader grab and composite analytes. This would indicate that further dredging would be of little value in trying to further reduce existing metals contained in the bottom sediment. Visual assessment of the ocean floor under the shiploader area following dredging, confirmed full removal of spilled concentrate materials. DEC believes that more dredging is unlikely to be successful in reducing metals concentrations and risks compromising any natural remediation that has already taken place at the spill site. DEC will continue to evaluate this conclusion as the TMDL is implemented, and will consider targeted removal if necessary. No changes have been made to the TMDL based on these comments.
18.Implementation: Conclusions (Incorporates individual comments from comment numbers 7 and 21.) Comment Summary: Table 2-1 lists designated uses that are not met due to contaminated sediments; shouldn’t a plan be developed to restore these uses?
Response: The goal of a TMDL is to allocate pollutant loads. Although highly recommended, states are not required by federal statute or regulation to develop TMDL Implementation Plans that define a set of actions such that water quality standards will be achieved. Section 6 contains the implementation and monitoring recommendations that may be included in a project plan. No changes have been made to the TMDL based on these comments. Comment Summary: Recommendations 2 and 4 of additional characterization is inconsistent with the TMDL findings of no impairments to water quality or marine species tissue, and should be removed from the recommendations. Response: The freshwater sampling program is part of the APDES permit, and since there have been no persistent exceedances, no impairment has been concluded. Recommendation 2 has been removed, and Recommendation 4 has been revised to include an assessment of overall background conditions for all media in the Hawk Inlet area (including freshwater). Changes have been made to the TMDL based on these comments.
20.Implementation: Remedial Action (Incorporates individual comments from comment numbers 2, 6, 8, 9, 11, 12, 13, 14, 18, 19, and 21.) Comment Summary: The draft TMDL does not provide a timeline for recovery or cleanup. Natural recovery has not improved water quality and allows for continued exposure to metal-contaminated sediments. Are the sediment transport processes and re-suspending of sediments understood? The remedial actions should be presented in a separate alternative evaluation section, and consider capping of the contaminated areas. Removal of metal-contaminated sediments using targeted suction dredging is requested. Shouldn’t an adequate cleanup in the loading dock area be required to address the anti-degradation policy? Is there a budget to complete this plan?
Response: The TMDL process gathers all available data and is a planning tool. The TMDL doesn’t provide a detailed feasibility study, a sediment transport study, or a comprehensive monitoring plan. As additional data is obtained, more defined remedial actions and monitoring plans can be developed outside of the TMDL process. Capping is a considered alternative and discussed in Section 6 Implementation and Monitoring Recommendations. The delineation of the contaminated sediment within the loading dock area and the option of a targeted removal of contaminated sediment also have been included in Section 6. Alaska applies its anti-degradation policy as a part of the process of providing a discharge authorization under an APDES permit. DEC currently has no dedicated funding for implementation of this TMDL. Changes have been made to the TMDL based on these comments.
Comment Summary: What can be done to reduce the exceedances in water and sediment at sampling stations 9, 60, 54 and 61, in sediment at Empire Mine, in tissue at sampling stations S-2, S-3, S-4, STN-1, STN-2 and STN-3? Shouldn’t biological samples be collected within the designated spill area? Enforceable regulations to prevent future pollutant releases are requested.
Response: Section 6 outlines the implementation and monitoring recommendations of this TMDL throughout Hawk Inlet. In addition, the best management practices are provided in the Hecla Greens Creek Mining Company Best Management Plan (revised December 2015), and the Hecla Greens Creek Mining Company Annual Best Management Practices and Storm Water Monitoring Report for year 2015 activities (dated March 2016). The implementation and monitoring recommendations and the best management practices should continue to reduce water quality exceedances. Biological sample collection is recommended in Section 6 Implementation and Monitoring Recommendations. The required best management practices contained in the permit have facilitated safe practices and avoided pollutant releases since the 1989 ore concentrate spill. Hawk Inlet TMDL: Public Notice Response to Comments May 2017 15 No changes have been made to the TMDL based on these comments.
Comment Summary: The references section cites Sediment Quality Guidelines. Technical Memorandum, January 2013, which in turn cites the Technical Resource Document on Monitored Natural Recovery (USEPA/600/R-14/083) dated April 2014. The resource document contained topics that were not addressed in the TMDL.
Response: The technical resource document provides detailed information on field-scale methodologies and approaches that can be used to measure and/or predict natural processes that contribute to the reduction of risks to human and ecological receptors at contaminated sediment sites. The TMDL document is not the mechanism to address all these facets, and future studies could be designed to address these topics. Changes have been made to the TMDL based on these comments.
Comment Summary: The decision not to clean up the ore concentrate spill until 1995, and continued elevated metals in current sediment samples is a concern.
Response: An ore concentrate spill occurred in May 1989. Routine sediment monitoring in September 1990 indicated a decrease in metal concentrations, but persistent elevated metals warranted the removal of the contaminated sediment. Preliminary testing in the summer of 1993 indicated the need for a commercial scale suction dredge to effectively cleanup the resident ore concentrates. In February 1994, the scope of work and bids were offered, and in April 1994 all required permits were obtained. In September 1994 dredging was conducted, and during the dredging process grab samples were collected by the divers. The confirmation samples showed that metal concentrations were at or close to pre-spill conditions. A total of 550 cubic yards of material was removed. The current sediment samples still have elevated concentrations, but orders of magnitude lower than the samples collected following the ore concentrate spill. DEC notes the concern expressed in the comment and has included a summary of the spill cleanup in the TMDL. Changes to the TMDL have been made based on these comments.
Comment Summary: Clarify whether station S-3 would be considered a candidate for targeted removal along with stations S-4, S-5S, and S-5N. The source of metals at station S-3 is currently unknown and elevated metals concentrations may be naturally occurring (non-anthropogenic source). Delineation of station S-3 would need to be accomplished before targeted removal could be implemented. Response: The delineation of station S-3 and evaluation of ambient conditions would need to be accomplished before targeted removal would be considered. This language has been added to the Implementation section. Changes to the TMDL have been made based on these comments.
22.Implementation: Responsibility (Incorporates individual comments from comment numbers 7 and 21.) Comment Summary: Is the spill site on public land, and if so, what is the process for placing a deed on public land?
Response: As noted in Section 6, the spill site is on private property, owned by HGCMC. Based on Department of Natural Resources files, HGCMC owns both the inter-tidal and sub-tidal land at the 303(d) listed area of concern. Changes to the TMDL have been made based on these comments.
Comment Summary: Does DEC have the authority to establish a TMDL at station S-3 without listing the site on the 303(d) list?
Response: Impaired waters only are added to a state’s list every two years. Between cycles, a state can develop TMDLs on impaired waters or areas discovered during the TMDL process if those waters would have been listed as impaired if information was known at the time the list was established (known as unlisted but impaired waters). Language regarding this process has been included in the TMDL report. Changes to the TMDL have been made based on these comments.
Comment Summary: More information is requested on the implementation plan and funding mechanism for the S-3 area and Empire Mine.
Response: The TMDL process gathers all available data and is a planning tool. TMDLs do not provide a detailed feasibility study, a sediment transport study, or a comprehensive monitoring plan. As additional data is obtained, more defined remedial actions and monitoring plans can be developed outside the TMDL process. Funding and responsible parties are not components of a TMDL document. Changes to the TMDL report have been made based on this comment.
26.Monitoring: Delineation of Impaired Area (Incorporates individual comments from comment numbers 9, 15, 17, 18, and 21.) Comment Summary: There were several comments asking that future monitoring allow for analysis of the impact of the removal of the 1989 ore concentrate spill including expansion of the sampling outward from the current delineated impaired area to sediment free of contamination. In addition, commenters asked that a monitoring plan be provided with specific research recommendations, including a plan to evaluate bioaccumulation of toxic metals that pose a risk to all trophic animals, including humans.
Response: The TMDL study evaluated all readily available data to identify impaired areas in which to provide load allocations. In the optional section on monitoring and implementation recommendations, the TMDL document recommends additional monitoring to further delineate the extent of the area(s) of impairment (see Section 6.2). Future monitoring should be conducted under a Quality Assurance Project Plan (QAPP). The QAPP would outline the specific goals of the sampling. The State of Alaska can provide assistance by analyzing fish tissue samples for any private entities collecting samples. Contact Christoff Furin: This email address is being protected from spambots. You need JavaScript enabled to view it., (907) 375-8211 or Dr. Robert Gerlach: This email address is being protected from spambots. You need JavaScript enabled to view it. for additional information. No changes have been made to the TMDL based on these comments.
30.Sediment Data: Available Data (Incorporates individual comments from comment number 21.) Comment Summary: Page 9 table at the bottom of the page - The sediment data for cadmium copper, lead, mercury and zinc is characterized as needing reductions in concentrations up to 92.3% to meet total maximum daily loads (TMDLs or sediment concentration equivalents based on the National Oceanographic and Atmospheric Administration “NOAA” Screening Quick Reference Tables “SQuiRT” benchmarks); however, the number of samples in the spill “delineated area” is inadequate to statistically support this statement. If the dock spill area was homogeneous over its 1.12 acre size, a minimal data set for USEPA ProUCL software which would generate statistical upper confidence limit (UCL) calculations for the average and upper bound value (for a data set at a 95% confidence level for example) may require 8-10 samples. However, this area is not homogeneous and only 2 sample locations within the spill “delineated area” were collected. Other aspects of heterogeneity at this location include that pockets of concentrated ore are located around spill area and there is historical debris at this underwater location related to a cannery fire. Other uncertainties include that vertical and horizontal accuracy and precision of the sample locations was not discussed. Other issues which were not addressed are related to sediment transport processes (e.g. erosion, transport, deposition, and tidal variations is large, 25 feet), physical properties (e.g. grain size, bulk density, cohesiveness, and bioturbation). The deficiencies are so numerous and significant that high variability in the data is can be expected. Therefore, the approach and plans presented in this document are technically unsound.
Response: The percent reduction is shown in the TMDL summary tables on pages 9 and 10 (now pages 1 and 2) to help show the extent of the necessary reductions based on the maximum metals concentrations found in the sediment. The target of the TMDL is actually the load allocation (LA), which is equivalent to the NOAA sediment ERLs minus a 10 % margin of safety (MOS). The allocations apply to the entire impaired area. No changes have been made to the TMDL based on this portion of the comment. Future sediment, water quality and tissue sampling in Hawk Inlet should be designed to add statistical strength to the data. This recommendation has been added to Section 6.2 of the TMDL. Changes to the TMDL have been made based on this comment.
31.Sediment Data: Data Presentation (Incorporates individual comments from comment number 21.) Comment Summary: Page 85 Figure 3-10, Page 86 Figure 3-19, Page 88 Figure 3-14, Page 89 Figure 3-15, Page 91 Figure 3- 18, Page 92 Figure 3-19, Page 94 Figure 3-22 and Page 95 Figure 3-23 - – these figures should be deleted. The presentation of the sediment data on a time scale portrays that the values are time dependent. However, as discussed above (see comment 3 above), the number of uncertainties associated with the data are significant so this presentation of the data misleading.
Response: A TMDL must use the best available data at the time of development. All available data were used and were shown over time to observe any trends in the data at each monitoring station. TMDLs also require that seasonality be considered; therefore, the metals data were analyzed based on the two seasons that data were available, spring and summer. The TMDL can be revised if additional information indicates that the assumptions underlying the TMDL are incorrect or that the loading capacity or allocations need to be revised. No changes have been made to the TMDL based on these comments.
33.Sources: Editorial (Incorporates individual comments from comment numbers 7 and 21.) Comment Summary: One comment asked why the ore concentrate spill isn’t treated as a point source since it’s a known source of metals to the inlet.
Response: A point source is defined in 18 AAC 83.990(48) as a source that generally applies to a discharge through a conveyance such as a channel or pipe. TMDLs define point sources requiring waste load allocations as sources that are or should be under a NPDES (APDES in Alaska) permit. The ore concentrate spill does not meet either definition and therefore it must be considered a nonpoint source. No changes have been made to the TMDL based on this comment.
Comment Summary: Comments also indicated that the ore concentrate spill is not the only known source to the impaired area near the loading dock. The previous fish cannery is an additional source. Response: Language has been added to the report to indicate that the fish cannery as well as the ore concentrate spill are the known sources to the impaired in the 303(d) listed area. Changes to the TMDL have been made based on these comments.
Comment Summary: Comments also asked to include the description of the inlet floor before and after the dredging project to clean up the spill site in 1994. Response: Language has been updated in the report to indicate what divers saw on the inlet floor before and after the 1989 spill based on the Kennecott Greens Creek Mining Company’s 1994 dredging report. Changes to the TMDL have been made based on these comments. Hawk Inlet TMDL: Public Notice Response to Comments May 2017 26 Comment Summary: In addition, there were several recommended editorial changes to help clarify existing information in the TMDL.
Response: There were several changes made throughout the TMDL to address additional minor editorial comments on sources of the metals impairment. Changes to the TMDL have been made based on these comments.
36.Sources: Prop Wash (Incorporates individual comments from comment numbers 9, 14, 19, and 21.)
Comment Summary: TMDL should require a study of prop wash and should include sampling during ship loading.
Response: The TMDL recommends sediment, tissue, and water quality sampling to delineate and monitor the impaired area around the ship loader. Those who implement the monitoring recommendations in the TMDL will have information on whether natural recovery of the impaired area is occurring. Marine Taxonomic Services, Ltd. (MTS), an independent contractor, is responsible for sediment sampling, tissue chemistry, and port inspections at the Greens Creek Mine. During the development of the TMDL, MTS provided DEC with a letter summarizing its observations related to contaminated sediment and sediment transport in Hawk Inlet. An excerpt from the letter states: In over 30 years of working at the Mine, usually twice per year, MTS staff have not noticed any increases in turbidity associated with ore-loading operations…tug boat propeller wash is only directed toward shore to any significant degree when ships are departing. During departure tugs pull concentrate ships from the facility which is oriented shore parallel. However, depths drop off quickly from the facility such that tug generated currents travel a significant distance before being able to contact the bottom. Additionally, the orientation of tugs to the ore ship being maneuvered is such that the ship acts to block the generated currents from reaching shallower waters on the lee side of the ship. MTS cannot make any guarantee that contaminated sediments have not been dispersed somewhat since the loss of containment in 1989…However, it is unlikely that berthing operations for ore shipments have any significant transport effects on sediments. No changes have been made to the TMDL based on these comments. Hawk Inlet TMDL: Public Notice Response to Comments May 2017 28
Comment Summary: Add a recommendation to obtain supporting data to show that prop wash from tug boats is not stirring up contaminants from the ore concentrate spill area.
Response: Water quality sampling under various environmental conditions for the loading dock area is included within Section 6.2 Monitoring Recommendations, and is recommended to provide data to evaluate contaminant disturbance from the areas of concern. Changes have been made to the TMDL based on these comments.
Comment Summary: Natural remediation cannot succeed because of prop wash from concentrate ships.
Response: Documentation received during the development of the TMDL indicates that prop wash does not have a scouring effect on bottom sediments. References to prop wash scour made in previous reports (e.g., Review of Essential Fish Habitat in Hawk Inlet Subsequent to Mining Operations [Ridgway 2003]) were made in error. No changes have been made to the TMDL based on these comments.
Comment Summary: Claims that prop wash scour is not occurring are unsubstantiated.
Response: Dive observations collected over 30 years of underwater sampling and facility inspections in Hawk Inlet (see the response to Comment 30.) indicate that no increase in turbidity associated with ore-loading operations has been observed. Lacking contrary data, diver observation is accepted as an accurate description of underwater conditions in the ship loading area. The TMDL can be revised if additional information indicates that the assumptions underlying the TMDL are incorrect or that the loading capacity or allocations need to be revised. No changes have been made to the TMDL based on these comments.
Comments Provided to the Department of Environmental Conservation, Hawk Inlet near Juneau, Alaska; Draft Total Maximum Daily Load Summary, Metals in Marine Sediments dated September 2016
From: Thomas Price <This email address is being protected from spambots. You need JavaScript enabled to view it.>
To: "Pikul Gretchen M (DEC)" <This email address is being protected from spambots. You need JavaScript enabled to view it.>
CC:
Gretchen Pikul
Alaska Department of Environmental Conservation
410 Willoughby Avenue, Suite 303
Juneau, Alaska 99811
Dear Ms. Pikul:
Electronic Review for the Environment, Inc. has reviewed the document dated September 2016 and has the following comments:
1) There is no signature block on the document; shouldn’t the preparer be identified and sign and stamp the document under professional certification?
2) On page 2 the 2nd bullet discusses that a deed restriction will be placed on the spill area, isn’t that public land? If yes what is the process for placing a deed on public land?
3) Page 9 table at the bottom of the page and page 12 paragraph 3 – the sediment data for cadmium copper, lead, mercury and zinc is characterized as needing reductions in concentrations up to 92.3% to meet total maximum daily loads (TMDLs or sediment concentration equivalents based on the National Oceanographic and Atmospheric Administration “NOAA” Screening Quick Reference Tables “SQuiRT” benchmarks) however the number of samples in the spill “delineated area” is inadequate to statistically support this statement. If the dock spill area was homogeneous over its 1.12 acre size, a minimal data set for USEPA ProUCL software which would generate statistical upper confidence limit (UCL) calculations for the average and upper bound value (for a data set at a 95% confidence level for example) may require 8-10 samples. However this area is not homogeneous and only 2 sample locations within the spill “delineated area” were collected. An aspect of heterogeneity at this location is that pockets of concentrated ore are located around spill area and there is debris at this underwater location related to a historical cannery fire. Other uncertainties include that vertical and horizontal accuracy and precision of the sample locations was not discussed. Other issues which were not addressed are related to sediment transport processes (e.g. erosion, transport, deposition, and tidal variations are large, 25 feet), physical properties (e.g. grain size, bulk density, cohesiveness, and bioturbation). The deficiencies are so numerous and significant that high variability in the data can be expected. Therefore, the approach and plans presented in this document are technically unsound.
4) Page 12 last paragraph second sentence refers to the ore spill as a “known source” however on page 114 last paragraph refers to Hawk Inlet as having only “non-point sources”; shouldn’t the spill area be considered a point source?
5) Page 12 last sentence on the page – how is the statement that the contaminated sediments will be buried by “clean sediments” being documented? Are the sediment transport processes (e.g. erosion, transport, deposition) understood enough to make such a general statement?
6) Page 14 Table 1-1 discusses that “prop-wash from tug boats maneuvering barges and ore ships during loading operations continues to re-suspend and mix concentrate with natural sediment in the vicinity of the spill” however at the bottom of page 107 and continuing onto page 108 the scouring of sediments is discussed as “unlikely” and that increased turbidity during tug boat operations was not observed. Apparently this issue is still not settled, a study should be conducted to find out if scouring of sediments occurs by the tug boat propeller(s).
7) Page 23 – The designated spill area is described as being located on a narrow (20-30 feet wide) shelf at a depth of 37 feet at the dock and dropping off steeply to 200 feet. If the sediment in the spill area has been scoured by the tug boat operations (from the time of the spill in 1989 until cleanup in 1995) and residual contaminated sediments continued to be scoured for 21 additional years to the present, the sediment may reasonable be expected to have settled down the slope and along both sides of the shelf. So shouldn’t that sediment be sampled down the slope and along the shelf to delineate the migration?
8) Page 25 Table 2-1 – The table lists designated uses which failed due to contaminated sediments so shouldn’t a reasonable plan be developed which restores these uses?
9) Page 26 Table 2-2 – The table shows water quality criteria on a 1-hour average. Shouldn’t water be sampled during periods when the tug boats are causing sediment scour from the propellers?
10) Page 30 section 2.2 Antidegradation – Shouldn’t a reasoned and adequate cleanup occur in the dock area consistent with the anti-degradation policy (18 AAC 70.015)?
11) Page 35 Figure 3-1 – The figure is not legible.
12) Page 37 Figure 3-3 shows sampling stations 9, 60, 54, and 61 which show exceedences of screening levels for cadmium, copper, lead, mercury, and zinc in water and sediment; can anything be done to reduce these exceedences?
13) Page 54 Table 3-11 – The table shows exceedences screening values for cadmium, copper, lead, and mercury in sediments at Empire Mine; can anything be done to reduce these exceedences?
14) Page 55 section 3.2.3.1 - The first paragraph discusses water quality at stations 106, 107, and 108; shouldn’t those samples be collected during conditions when the tug boat propeller scour of sediments is occurring?
15) Page 59 Table 3-13 – The water quality data near the loading dock shows exceedences of screening levels for copper; can anything be done to reduce these exceedences?
16) Page 61 Table 3-14- the samples at S-2, S-3, S-4, STN-1, STN-2, STN-3 show exceedences of the recommended screening values; can anything be done to reduce these exceedences? The sample location for S-4 is located near but outside of the designated spill area. Shouldn’t biological samples be collected within the designated spill area?
17) Page 85 Figure 3-10, Page 88 Figure 3-14, Page 91 Figure 3-18, Page 94 Figure 3-22 - – These figures should be deleted. The presentation of the sediment data on a time scale portrays that the values are time dependent. However, as discussed above (see comment 3 above), the number of uncertainties associated with the data are significant so this presentation of the data is misleading.
18) Page 86 Figure 3-19, Page 89 Figure 3-15, Page 92 Figure 3-19, Page 95 Figure 3-23– These figures should be deleted. The portrayal of the sediment data on a time scale portrays that the values are time dependent. However, as discussed above (see comment 3 above), the number of uncertainties associated with the data are significant so this presentation of the data is misleading.
19) Page 113 section 5.6 Seasonal Variation and Critical Conditions – Delete this section, the information is inadequately supported and contradictory (e.g. page 114 second full paragraph states that “there is no statistical significance to seasonality in the data” and the next paragraph discusses that “spring through early fall months reflect the critical period”). The data set is not robust enough to draw conclusions about seasonal variations.
20) Page 115 Implementation – The first paragraph discusses the possibility of dredging in the spill area however that type of discussion should be presented in a cleanup alternatives evaluation section. Later in the paragraph the discussion of dredging could suspend sediments and kill organisms; a more detailed handling of alternatives is needed (e.g. engineering controls might mitigate that those concerns). Any cleanup alternatives evaluation should consider capping the contaminated areas.
21) Page 115 Implementation – The second paragraph discusses the debris at the designated spill area complicates the cleanup, the possibility of removing the debris should be considered.
22) The references section cites DEC 2013 Sediment Quality Guidelines which in turn cite the Technical Resource Document on Monitored Natural Recovery (USEPA/600/R-14/083) dated April 2014. This guideline document contains the following topics which were not addressed and which should be considered:
a) Natural sediment, physical processes, chemical, and biological processes
b) Risk reduction processes including isolation/burial, dispersion, sequestration, contaminant transformation.
c) Source history and control, lines of evidence, conceptual site model.
d) Sediment transport processes (erosion, transport, deposition)
e) Physical properties (grain size, bulk density, cohesiveness, bioturbation).
f) Measurements: (core analysis, surface, bathymetry, watershed mass balance)
g) Uncertainties in determining reductions in surface sediment contamination
h) Predicting sediment erosion and transport (tidal influences too)
i) Fate of inorganic contaminants in sediments
j) Biogeochemical processes that affect metal behavior
k) Biogeochemical process affecting speciation and bioavailability of metals in water and sediment
l) Metal specific behavior for cadmium copper, lead, mercury and zinc.
m) Sediment sampling for metals: methods of collection and analytical considerations.
n) Analytical approaches to metal speciation in sediments.
o) Long-term monitoring and site forecasting with predictive models.
p) Metrics for long term monitoring
q) Predicting long-term recovery.
Sincerely yours,
ELECTRONIC REVIEW FOR THE ENVIRONMENT, INC.
By: Tom Price, Director
P.O. Box 2756
Berkeley, CA 94702