Kiefer, Robyn V CIV USARMY CENWK (US) Hooper, Charles A ...Recommend that 2nd sentence be clarified...

From: Kiefer, Robyn V CIV USARMY CENWK (US)To: Hooper, Charles A.; Phillips, ToddCc: Juett, Lynn; Jump, Christine; Young, Scott E CIV USARMY CENWK (US); Leibbert, Jason M CIV USARMY CENWK

(US)Subject: USACE Comments - BLRADate: Tuesday, December 12, 2017 7:56:59 AMAttachments: USACE Comments - Final #2 BLRA Nov 2017 and Backcheck of Previous versions.pdf

West Lake- USACE Comment Backcheck of Nov 2017 BLRA MASTER 12-12-17.xlsx

Chuck/Todd:

See attached USACE comments on the BLRA dated Nov 2017. The attached includes backcheck of commentsmade on the Oct 2016 and June 2017 versions of the BLRA. Comments that were not addressed are highlighted inyellow.

We will plan to discuss some of these after the RIA conference call on Wednesday. If you have any questions in theinterim, please let me know.

Thanks,

Robyn

Robyn KieferProject ManagerUS Army Corps of EngineersKansas City District

Phone: 816-389-3615
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]

DEPARTMENT OF THE ARMY CORPS OF ENGINEERS, KANSAS CITY DISTRICT

635 FEDERAL BUILDING 601 E 12TH STREET

KANSAS CITY MO 64106-2824

Printed on Recycled Paper

December 12, 2017 Mr. Chuck Hooper, Radiation Safety Officer U.S. Environmental Protection Agency Region 7 11201 Renner Boulevard Lenexa, KS 66219 Dear Mr. Hooper: The U.S. Army Corps of Engineers (USACE) has completed a review of the “Updated Baseline Risk Assessment, West Lake Landfill Operable Unit-1” dated November 2017 and prepared by Auxier & Associates, Inc. of Knoxville, Tennessee for Engineering Management Support, Inc. of Lakewood Colorado. Comments for this second “Draft” Baseline Risk Assessment are attached. USACE has also completed back-check of comments provided for the “Updated Baseline Risk Assessment, West Lake Landfill Operable Unit-1 dated October 2016 and June 2017. Backcheck of comments made on these “Draft” Baseline Risk Assessment reports are also attached.

USACE is available to participate in a comment resolution meeting upon request. Respectfully, Robyn V. Kiefer Project Manager CC: Scott Young-CENWK-PM-E Jason Leibbert-CENWK-ED-E PDT

1

West Lake Landfill Superfund SiteBLRA - Summary of comments on Oct 2016 BLRA Review and subsequent backchecks.

Comment #Reference: Section/ Paragraph/ Appendix

Commentor Comment (October 2016 BLRA) Discussion with EPA on 4/12/17 regarding how EPA will address the BLRA comments with PRPs

USACE Backcheck of comments against Draft Final BLRA report dated June 2017 USACE Backcheck of comments against Draft Final #2 BLRA report dated

11-13-2017

1 Table of Contents Twigg Attachments do not appear in the Table of Contents. Please revise accordingly. EPA concurs Not Addressed. EDITORIAL COMMENT - DEFER TO EPA ON INCORPORATION

2 Executive Summary and rest of report

Kiefer

Editorial Comment : Recommend the words theoretical and hypothetical be replaced with words like potential or "assumed". The terms "theoretical" and "hypothetical" can sometimes be misconstrued as not a realistic possibility and can also be received by the public as being dismissive, especially when they are used so much. You should make one statement early on to clarify that these are hypothetical or assumed, and then recommend removal from the rest of the report

Generally agree, try to keep comments toward key issues - is significantly changes meaning, then agree. Wholesale removal not an issue. USACE has no issue with not including. USACE looking at it from public perception

Not passed along to PRPs, therefore no backcheck required. Closed NO BACKCHECK REQUIRED

3 Executive Summary Paragraph 2

KieferThird sentence: "and compares those risk estimates to mandated CERCLA criteria." Please clarify - do you mean compares those risk estimates to the upper end of the CERCLA acceptable risk range? If so, please use that specific language as "mandated CERCLA criteria" is vague.

4 Executive Summary Paragraph 4

Kiefer

First sentence states "…that exceed CERCLA risk criteria for on-property Landfill workers….". Please clarify that is does not exceed the CERCLA acceptable risk range to remove any ambiguity. Similarly with the last sentence: "there is a chance that CERCLA risks may exceed the programmatic threshold criteria set by EPA's CERCLA program". Please clarify that you are referring to the CERCLA acceptable risk range. Consistency in use of terms is important for the public to understand what you are referring to and use of various terms when you are simply referring to the CERCLA acceptable risk range can be confusing.

5 Executive Summary, ES 1. Last Bullet

KieferEditorial Comment: Recommend it read "This final step combines the results of the first three steps to identify the largest sources of potential risk that may be posed by COPCs in OU1 and determines whether these potential risks exceed the CERCLA acceptable risk range."

6 Executive Summary ES-1 pg. 10 (pdf)

J. Donakowski

The statement is made "Following EPA directives for radiological sites, the future scenario evaluated radioactivity 1,000 years in the future…". Please cite/reference this directive. In Section 3.2.1, footnote 11 indicates this is driven by 10 CFR 61 and 40 CFR 192 (UMTRCA). The time frame for required evaluation may be ARAR driven, given that peak Ra-226 concentration will occur ~9,000 years in the future. Per OSWER 9285.6-20 "In cases where decay products have greater radiotoxicity than the original radionuclide, the potential radiation dose and health risk may increase over time; in such cases, the exposure assessment should consider the change in concentrations of all decay products over time to determine the time of maximum potential impact."; defer to EPA on whether 1,000 years is an appropriate evaluation time period given the above cited potential ARARs and OSWER language.

The best written form for this issue. EPA will likely use most of this. Will direct PRPs to appropriately address how 1000 years is appropriate for evaluation in this BLRA. Ex: Certain pieces of UMTRCA, cerntain OSWER guidance that speaks to 1000 years. This is a sensitive issue to public. EPA will tell RPs to do calc of how much ingrowth will occur and when it occurs. Strategy is to hide nothing and have this all on record in BLRA. USACE is good with this.

This is addressed as footnore 7 on Page 63. It may be better served appearing in the text body itself, and earlier in the document.

EDITORIAL SUGGESTION ON BACKCHECK, DEFER TO EPA WHERE IT IS LOACED. COMMENT CLOSED.

7Executive Summary

ES 1. 2nd to last paragraph

Kiefer Recommend removal of term "CERCLA risks" and just use "risks" or "human health risks". same as 3-5. USACE is good with this. EPA comment VII . RPs using ILCR. Closed NO BACKCHECK REQUIRED

8 Executive Summary ES 1. Last Paragraph

Kiefer

radioactivity 1,000 years in the future." recommend removal of "in order to provide a conservative assessment of potential future exposures" because ingrowth continues for up to 9,000 years, therefore, calling it "conservative" does not seem appropriate.

same as 6. USACE is good with this. Closed NO BACKCHECK REQUIRED

9 Executive Summary ES 2. 1st paragraph

Kiefer Editorial Comment: Recommend removal of "Among other risks,". Also recommend intro stating that BRA assesses Cancer and Non-Cancer Risks. Then go into Cancer Risk discussion then Non-Cancer Risk Discussion

EPA not providing editorial comments. EPA is considering adding comment related to this because it does change meaning.

Not passed along to PRPs, therefore no backcheck required. Closed NO BACKCHECK REQUIRED

10 Executive Summary ES 2. 1st paragraph

Kiefer

Recommend that 2nd sentence be clarified that the risk calculated as a result of the anticipated exposure due to the landfill is the incremental risk to the exposure to specific carcinogens that people receive on a daily basis. Also, the sentence that states that 1x10-4 , or a 0.01% risk increase to the hypothetical receptor are acceptable for purposes of CERCLA risk assessment could be stated more clearly, possibly by stating EPA considers an acceptable incremental risk range to be between 1x 10-4 and 1x 10-6

EPA wants them to clean this up and address Closed - language removed NO BACKCHECK REQUIRED


J. Donakowski

The statement is made a 0.01% chance increase - to the hypothetical receptor are acceptable for purposes of CERCLA risk assessment." Consider qualifying as "generally acceptable" as, per OSWER 9285.6-20 "Consistent with existing Agency guidance for the CERCLA remedial program, while the upper end of the risk range is not a discrete line at 1 x 10-4, EPA generally uses 1 x 10-4 in making risk management decisions. A specific risk estimate around 10-4 may be considered acceptable based on site-specific circumstances. For further discussion of these points and how EPA uses the risk range see OSWER Directive 9355 0 30 Role of the Baseline Risk Assessment in Superfund Remedy Selection

EPA wants them to clean this up and address While somewhat addressed on Page 110 it may be helpful to directly cite the OSWER guidance.BACKCHECK SUGGESTION IS EDITORIAL TO PROMOTE CLARITY. DEFER TO EPA ON INCORPORATION. OTHERWISE, COMMENT CLOSED.

12 Executive Summary ES 3. 2nd paragraph

Kiefer Last Sentence: "…about current and reasonably anticipated future conditions at the Landfill were used to select representative human receptors…" Should this state "future land use scenarios were used to select……receptors...."?

Terminology is confusing - they need to be consistant with RAGS and guidance on anticipated future site uses. Wont' be exactly this, but comment will addrses terminology

Closed - language removed NO BACKCHECK REQUIRED

13 Executive Summary ES 3. 3rd paragraph

Kiefer States "CERCLA risk" throughout. Seems like "human health risk" is more accurate. Will ask PRPs to incorporate Closed - using ILCR NO BACKCHECK REQUIRED

14 Executive Summary ES 3. 3rd paragraph

Kiefer

Editorial comment: last sentence: Recommend removing the "...even taking into account 1000 years of decay and in-growth " and replacing it with "...assuming no remedial actions are taken and accounting for a period of 1,000 years of decay and in-growth." While guideance says to take into account 1000 years of in-growth and decay, levels will continue to rise for 9,000 years. Use of the word "even" can be construed as deminishing the importance.

Same as 1000 year. Closed NO BACKCHECK REQUIRED

15 Executive Summary ES 3. last paragraph

Kiefer For clarity, recommend adding "remedial" to the"….potential of possible future remedial alternatives as part of…." Will ask them to add. Closed NO BACKCHECK REQUIRED

16

Executive Summary ES 3 - 2nd to last

paragraph and Table ES-1

KieferThe distinction between on-site vs. on-property gets further confusing by the reference to "on the Landfill property itself". I think these definitions are most clearly stated in Section 3.1. Please consider including simple definitions of these terms in the Executive Summary.

Adding this comment - asking them to define it in Exec summary.


ADDRESSED, COMMENT CLOSED.EPA comment VII, others? - RPs are now using Incremental lifetime cancer risk. ILCR. Recommed that acceptable ILCR be defined. ILCR is not defined until Section 2.3 of the report Otherwise, acceptable.

Speaks to cavalier language used by Risk Range. EPA taking a careful look at wording in Section 1. EPA agrees with comments 3-5. Will add a comment similar to this and may be more directive.

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17 Table ES 1 Kiefer

Aren't there current on site construction worker scenarios (cap installation, isolation barrier installation, investigative work)? Recommend this be addressed as a footnote (it is addressed elsewhere in the report, but it draws questions in the Executive Summary). What about the on-site commercial worker (the guy who reads the gas meter that is within the OU1 Area 1 fenced near the landfill entry building?). Granted the exposure for the on-site commercial worker is extremely limited; however, it is still an exposure.

EPA wants to pass on part of it. EPA doesn't typically throw into risk assessments work done specific to the CERCLA work. EPA agrees about the OU1 Area - its not a gas meter, it's a septic tank. They installed a soft pipe so they don't have to go on Area 1. Still need acknowledgement of that.

Reference Section 3.1.5.1 - states there is electrical workers on panels inside Area 2. It is acknowledged as is the septic tank; however, I'm not sure you can eliminate this as a potential receptor pathway as it has been done in Section 3.1.5.1. Should this potential pathway this be added to table?

NOV 2017 VERSION OF BLRA ADDRESSES WHY THESE UTILITY WORKERS WERE NOT INCLUDED FOR EXPOSURE. COMMENT CLOSED.

18 Table ES 2 Kiefer Recommend highlighting or bolding those receptors that have risk levels outside the acceptable risk range. EPA concurs Table ES-2 has been removed. Levels exceeding the CerCLA acceptable Risk Range have not been bolded.EDITORIAL COMMENT - DEFER TO EPA ON INCORPORATION. COMMENT CLOSED

19 Table ES-2 TwiggFootnotes a and b do not appear anywhere in the table. Also, incidental lifetime cancer risk values are not rounded as indicated in footnote a.

EPA concursFootnotes revised; however, incidental lifetime cancer risk (ILCR) is still presented to three significant digits. Typically, ILCR is presented as one or two significant digits. Defer to EPA on rounding ILCR to one or two significant digits.

EDITORIAL. DEFER TO EPA ON ROUNDING, NO BACKCHECK REQUIRED


J. Donakowski

Given the earlier statement "In order to conservatively evaluate potential risks, the EPA CERCLA assessment process directs that both curent and future scenarios assume that no remediation would occur at OU-1." it seems inappropriate to state here that "... under future conditions, it will be imperative to prevent uncontrolled vegetative growth to maintain the integrity of the landfill cap...". Please reconcile/clarify.

EPA wants to understand impact of comment. It's in Eco risk section. PRPs stating in future, types of conditions now that allow for habitat such as squirrels and small game, in future, they don't have to interpret future eco risk? USACE seems they are trying to jsutify their risk assessment by maintaining vegetative cover. EPA will pass along, but not sure how it will be sent over.

No vegetative cover was assumed for future scenario.

UPDATED BLRA ASSUMES VEGETATIVE COVER WOULD BE MAINTAINED IN A WAY TO REDUCE LARGER ANIMAL HABITAT. GENERAL SCREENING LANGUAGE IN MAIN DOCUMENT SUGGESTS COMMENT WAS ADDRESSED.. CLOSE COMMENT

21 Section 1.1 paragraph 1

Kiefer Recommend referencing the document that was originally prepared (App A of OU1 RI) Will add comment to reference RI addendum Original BLRA not referenced, just states "this update"NOT ADDRESSED; HOWEVER THIS COMMENT WAS FOR CLARITY TO ENSURE FIRST BLRA WAS REFERENCED. IT DOES NOT IMPACT THE RESULTS OF THE BLRA, THEREFORE, THIS COMMENT IS CLOSED.

22 Section 1.1 paragraph 2

Kiefer Recommend identifying the regulated landfill as the Bridgeton Landfill

General descriptions. EPA has already given prescriptive direction on RI Addendum. This should be addressed. Will pass along comment referencing that this guidance has already been given.

Not addressed. This is the only place it refers to the Bridgeton Landfill as the "regulated landfill" throughout the report, it refers to it as "bridgeton Landfill" > recommend this be implemented.

NOT ADDRESSED; HOWEVER THIS COMMENT WAS FOR CLARITY TO ENSURE FIRST BLRA WAS REFERENCED. IT DOES NOT IMPACT THE RESULTS OF THE BLRA, THEREFORE, THIS COMMENT IS CLOSED.

23 Figure 3, pg. 15 Rankins The boundary used to identify the areal extent of the buffer zone is difficult to discern. EPA will ask for exact copy of figure in RI if they plan to put it in BLRA. EPA concurs this is not a good quality figure.

Closed. The revised figure is of much better quality and easier to read. The buffer zone is more easliy discernable. NO BACKCHECK REQUIRED

24 Section 1.2 KieferThere is a reference to "the Remedial Investigation Report". There have been more than one addendum, recommend a thorough reference as to which document contains the detailed descriptions.

Will add holistic comment to ensure that when they ref a specific report that they use full name of the report.

Closed NO BACKCHECK REQUIRED

25 Section 1.2.1 pg. 16 (pdf)

J. Donakowski Given that OU-3, Groundwater, has now been added, consider revising to include mention that groundwater will be addressed separately from OU1 and isn't included in this BLRA.

EPA concurs. Will turn it into an overarching comment. EPA gave extensive direction to PRPs on RI about GW and OU3 and what's appropriate for OU1. All portions of doc that discuss GW need to consider comments made in RI. Will also list sectios where they talk GW and will give specific direction.

Closed. That groundwater is addressed in more detail as part of OU3 has been clarified. NO BACKCHECK REQUIRED

26 Section 1.2.3 Rankins

The addition of a figure(s) showing the OU-1 areas with locations and areal extent of RIM identified, as well as cross-sectional views of the landfill areas showing layers of interest (for example, non-combustible cover, soil layers, contaminated layers, etc.), would have been helpful for this review. We recognize that the BLRA is part of the RI and that some of these figures may likely be in the RI. If so, they should be referenced.

EPA will expand comment to reference sections of RI where you can find the data that is being used.

Text was added to Sections 1.2.3.1 and 1.2.3.2 for Areas 1 and 2, respectively, that refer to Figure 4-22 of the RI Addendum (RIA). For Area 1, the reference to Figure 4-22 is the 7th sentence of of the second paragraph of Section 1.2.3.1, which reads:"All of the landmarks mentioned above are shown in Figure 4-22...". Perhaps the sentence should be modifed to read: "All of the landmarks mentioned above, including the extent of the non-combustible cover over areas of RIM, are shown in Figure 4-22..." Also, the definition of the pink line in Figure 4-22 in the RIA is confusing. The legend defines it as "Edge of 2 Inch minus Non-Combustible Cover". What does this mean? If this is the extent of the non-combustible cover, what is the signficance of "2 Inch minus Non-Combustible Cover"? Perhaps also refer to Figure 7-1 of the RIA showing cross-sectional view with geostatistical estimate of RIM in both areas.

COMMENT OVERCOME BY CHANGES IN DOCUMENT. FUTURE COMMENTS WILL PICK UP ANY CONTINUED CONCERNS. COMMENT CLOSED.

27 Section 1.2.3.2 KieferRefers to an asphalt-paved area and diesel UST. Recommend this be shown on one of the figures, if not in the BLRA, then in the RI figures.

Used to be asphalt parking lot on top of where high surf conce RIM in OU1. There might have been overburden there. They had to move that to put in parking lot or was working in it. When installed combustible rock , put on top of asphalt. UST is still there. Show approximate location. As part of remedy, still need to fill it if it isn't removed. EPA will make comment with respect to UST. USACE concurs.

Closed - it is shown in the RI figures NO BACKCHECK REQUIRED

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28 Section 1.2.3.3 Kiefer2nd paragraph, last sentence states, "the contamination is generally considered to be located at the top of the ground surface". Has there been sampling to confirm there is no subsurface contamination? If so, recommend more definitive statement rather than use of the words "generally considered".

PRPs didn't do good job of justifying their statements. There has been sampling of xroads and buffer zone. EPA will pass along comment to have PRPs reference that information and state that data is being used in BLRA. Generaly considered at surface in the 1990's. Owners did dirt work and built parking lot over that area where they weren't supposed to. That is why they used "generally considered". USACE feels this should be better explained. EPA will have them reference the data.


29 Section 1.2.4.1 pg. 19 (pdf)

J. Donakowski Although unlikely given the reasons outlined in this paragraph, "trespassing" implies bypassing existing Site security measures; defer to EPA on whether the trespassing/transient scenario is a potentially complete pathway.

EPA agrees currently tresspassing is unlikely. Will ask PRPs to outline justification for why no tresspassing, just don't say because of site security.

Closed. Current trespasser discussed on page 8, trespasser receptor addressed in future transient receptor scenario NO BACKCHECK REQUIRED

30 Section 2.1 first paragraph

Kiefer "and the additional characterization of Areas 1 and 2 performed in 2016." Where is this data presented? Need reference.

EPA will have PRPs reference it. Closed - reference added NO BACKCHECK REQUIRED

31 Section 2.1 2nd Bullet, pg 16

J. DonakowskiWhile "duplicate" data is generally not considered to be "site" data, if there were instances where the duplicate data was considerably higher, it may be preferable/more conservative to utilize the duplicate data rather than the original data. This could be addressed in Table 53; defer to EPA on the inclusion of select duplicate data

EPA concurs. Duplicate data not discussed in BLRA, data usability report not reviewedNO NEED TO ADDRESS (NO SIGNFICANT IMPACT TO RESULTS). COMMENT CLOSED.

32 Section 2.1, Page 17 (report)

Twigg First bullet mentions results from a set of 23 samples that were still undergoing evaluation. Will these data be incorporated at a later date? If not, justification must be provided as to why this data is or is not going to be included.

EPA concurs. There will be rvision to bulilet with explanation why data not being included in analysis. The 23 samples are the ones Cotter decided to do in addition to 2015 work. They got 6 or 7 results for Th230 that were multiple orders of magnitude above any level ever seen at West Lake. They were taken from borings from previous investigations where data existes. Test America was lab that performed analysis. Thes samples were reanalyzed at SWRI lab confirmed earlier results previous to Cotter's sample results. There is a technical response from EPA to PRPS to be transparent and include that information in RI Addendum. It will tell PRPs not to use those samples (Th230) results in BLRA. EPA looked at Level 4 lab results., so that doesn't seem thatt the lab results were hacked. There was oversight from other PRPs while Cotter took samples. Tom saw a part of their sampling, but not all of it.

Closed - text revised, and data usability report in Appendix D-12 of the RI addendum addresses the comment. NO BACKCHECK REQUIRED

33 Section 2.1 4th bullet J. Donakowski It is more conservative to use the MDA, rather than half the MDA, if a result is reported as "null". This could be addressed in Table 53; defer to EPA on how to treat

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37 Section 2.1 pg. 25 (pdf) J. DonakowskiWhile a sample collected from inside a buried paint can may not fit the site conceptual model, if sample results are elevated it may still be a relevant sample (i.e. RIM impacted breached container) and warrant consideration. Results of this sample are not discussed in section 2.5.4.

EPA will ask why they don't use it other than "it was by a paint can". USACE believes that co-located material doesn't preclude it from being used. There are reasons why something may not be used, but co-location is not necessarily a reason. EPA Concurs.

Closed. This sample presented and discussed as footnote b on page 30 NO BACKCHECK REQUIRED

38 Section 2.2, Page 17 (report)

TwiggThird paragraph discusses modification or exclusion of data based on statistical outlier tests. Please provide greater detail on this process. Without additional detail, readers may get the impression that potential hot spots may have been excluded from the risk assessment. The statistical outlier tests could be added as an Attachment.

EPA sees no connection between 2.2 and 2.1. EPA has discussed with PRPs about how they discuss data and why it's rejected and then they go into 2.2 and state procedure that doesn't fall in line with this process. PRPs says there is no other data being rejected. EPA has comments that will heavily edit this section. We can't see how they are using this methodology to reject data.

Detail not provided in text, as text was revised to be much more general. Data usability report was included as Appendix D-12 of the revised RI Addendum.

Data Usability Report (Appendix D-12 in the RI Addendum) adequately addresses this comment COMMENT CLOSED.

39 Section 2.2 pg. 25 (pdf)

J. Donakowski

The statement is made "If the data's fitness of representation was determined to be unsatisfactory, the individual database records involved were annotated to reflect this decision and those individual records were either modified or excluded from subsequent evaluations." It is unclear what type of modifications would have been made, how many data points, if any, were excluded based on this review, and whether this review differs from the discussions presented in Sections 2.1 and 2.4. Please clarify.

Same as 38. EPA concurs. data usability report not reviewed Duplicate comment (as #38 Twigg). CLOSE COMMENT.

40 Section 2.3, Page 17 (report), Footnote 4

Twigg Were samples outside the boundaries of OU-1 included in the calculation of exposure point concentrations (EPCs)? If so, this would likely lead to lower EPCs. If not, please explain.

USACE: As long as long as the EPC definition is clear that's fine, it is not clear as written. It needs to be repreasentative of OU1 and what data is included in it. EPA: is tyring to figure out how to respond - it may be to have PRPs clarify or to give them direction. Not sure of response just yet.

Closed - text revised and additional detail provided in data usability report NO BACKCHECK REQUIRED

41 Section 2.4.3 and Table 5

Rankins

The first paragraph of Section 2.4.3 cites one of EPA's criteria for not including a chemical in a quantitative risk assessment: "(2) present at low concentrations (i.e., only slightly elevated above naturally occurring levels)". Table 5 screens out the following metals based on comparisons with corresponding Region 8 nutrient screening levels which appear to be elevated well-above maximum background (bkgd) levels measured by the USACE for the STL FUSRAP sites: cobalt (max = 2,700 mg/kg; bkgd = 16 mg/kg), copper (max = 33,000 mg/kg; bkgd = 1,660 mg/kg), manganese (max = 4,900 mg/kg; bkgd = 975 mg/kg), and selenium (max = 250 mg/kg; bkgd = 0.96 mg/kg). Please note that the aforementioned maximum background values are site-specific FUSRAP values for the St. Louis Downtown Site. Please provide additional justification for screening out these metals from the risk analysis or include them as constituents of potential concern for quantitative risk evaluations.

EPA will have PRPs compare to RSLs.

Section 2.4.3 of the October 2016 Updated BLRA, which was initially the subject of this comment, is now Section 2.3.1 in the June 2017 version. The original comment has not been addressed. The last paragraph of the section states that: "Calcium, copper, fluoride, iron, manganese, magnesium, potassium, selenium, sodium, and zinc were screened out based on the UTLDI comparison." Typically, the use of values such as UTLDIs, or even U.S. FDA recommended daily allownces (RDAs) is applied to the screening of macronutrients (e.g., calcium, magnesium, potassium, and sodium). The macronutrients are usually present naturally in the environment at high concentrations and exert low toxicities. Becasue of their high abundance and low toxicities, there are no cancer/non-cancer toxicity criteria available from EPA for assessing risks/HIs. The other inorganics mentioned in the last paragraph of Section 2.3.1 of the June 2017 BLRA are micronutrients and naturally present at low concentrations in the environment. Becasue of their higher toxicities (i.e., relative to the macronutrients), EPA has developed RSLs for most of these elements. In order to eliminate these elements from quantitative risk evaluations, it should be proven that they are within background levels and are not site-related. Otherwise, the screening of these elements should be conducted based on RSL comparisons. Please rescreen all micronutrients listed by Region 8 (chromium, cobalt, iron, manganese, molybdenum, phosphorus, selenium, and zinc) based on RSL comparisons, and not not based on nutrient screening values, if the cannot be proven to be non-site-related and within background. Also, it should be noted that based on the nutrient UTLDI-based screening levels provided in Table 5, the maximum screening concentrations of chromium and cobalt exceed the respective nutrient screening levels.


42 Section 2.4.4 4th paragraph

Kiefer For composite worker, why not look at inhalation because soils is the source medium? To be conservative, you would want to include inhalation.

USACE concern is that PRPs rule out inhalation without appropriate justification. EPA concurs and will ask for clarification.


43 Section 2.5.1 J. Donakowski

The statement is made "uranium-235 concentrations are commonly overestimated when samples are assayed for uranium isotopes by alpha spectroscopy." Is this due to interference from U-234 taildown or some other analysis interference/mechanism? Please provide a reference/citation for this statement.

If U-235 is quantified via the 185.7 keV line via gamma spectroscopy, interference from the 186.2 keV line from Ra-226 may be a significant factor in overestimating U-235 when assayed via gamma spectroscopy.

EPA concurs and is pasing along a comment similar to this.

Closed: U-235 isoptopic data discussed in more detail on page 17 NO BACKCHECK REQUIRED

44 Table 1 (and in general)

J. Donakowski It is helpful for readability if values greater than 1,000 utilize a comma to delineate the "thousands" place, "millions" place, etc.

Editorial - not passing editorial along. USACE is fine with that.

Not passed along to PRPs, therefore no backcheck required NO BACKCHECK REQUIRED

45 Section 2 Tables J. DonakowskiTables are provided for "surface" and "all soil depths". It would be helpful for evaluation to also include tables for "subsurface only"

surface - samples within top 12" . All soil depth includes all samples. EPA wants to understand what USACE feels will be gained from a subsurface only data. When do current risk, surface drives risk. All soil EPC isn't used for determination. Trash data is not being used at all to come up with Radon source terms. PRPs are using flux measurements. USACE -typically wants to see more thorough breakout. Ok if EPA decides this isn't necessary and doesn't want to have data broken out based upon EPA's determination on how PRPs ahve used data.

No subsurface only breakout, all data used for future risk evaluations. COMMENT NOTES THAT IT IS HELPFUL FOR CLARITY/REVIEW, BUT THIS DOES NOT CHANGE THE BLRA RESULTS. CLOSE COMMENTS.

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46 Section 3.1.2.2 2nd Paragraph

Kiefer Could erosion or subsidence cause potential exposure to non degredated VOCs?

MDHSS has lots of comments regarding this pathway. Explain why they are/are not risks. USACE just wants it to be clear why these are eliminated as pathways.

Does not address any erosion/subsidence potential to release VOCs from non degraded VOCs.ADDRESSES THAT VOLATILE GAS MEASUREMENTS DURING DRILLING DID NOT IDENTIFY VOCS IN SUBSURFACE. WHILE THIS DOESN'T NECESSARILY JUSTIFY ELIMINATING VOCS AS A PATHWAY, THE PRIMARY CONCERN IS RIM, NOT VOCS. THEREFORE, THIS COMMENT WILL BE CLOSED.

47 Section 3.1.2.4 Kiefer Radionuclides are addressed, what about non radionuclides? EPA - passing along, but will be addressed in OU3. Closed NO BACKCHECK REQUIRED

48 Section 3.1.2.4 pg. 40 (pdf)

J. DonakowskiWhy is uranium leaching not also considered given that uranium concentrations up to ~1,800 pCi/g of Unat are present at depth in Area 2? The associated distribution coefficient for uranium can be lower than for those of radium, thorium, and protactinium depending on site conditions.

EPA is asking for major revisions to Section 3.1.2.4. Will also be part of OU3 discussion.

Closed: Uranium evaluated as part of this assessment NO BACKCHECK REQUIRED

49 Section 3.1.2.4 KieferRecommend that if leaching from soil to groundwater is not considered as part of OU1, it should be stated that any leaching will be evaluated as part of OU3.

EPA - passing along, but will be addressed in OU3. Closed NO BACKCHECK REQUIRED

50 Section 3.1.2.5 pg. 40 J. Donakowski

While runoff of contaminated material in surface water may no longer be an applicable release mechanism, if no remedial action is taken, there is the potential for surface erosion over the course of 1,000 years to expose material which would otherwise be considered "subsurface" material, and for a reduction in the amount of cover material present. If erosion occurs at a rate of 0.1 cm/year, after a 1,000 year period, up to 1 m of cover may be removed and cover material will be relatively "shallower" compared to initial site conditions.

EPA agrees that site needs to be considered like no cap is being placed. How consider surf water runoff exposure pathway given soil contamination in future? USACE: we don't think this is a viable exposure pathway, but removing soil and over time, could be big risk driver. USACE considers loss of some surface cover in future. EPA: How do they evalute this? USACE: chop off all data < 1m. Does USACE have reference? USACE: Resrad default erosion rate.

Closed: Runoff further discussed on Page 54 NO BACKCHECK REQUIRED

51 Section 3.1.4 Kiefer

Last paragraph states that a systematic process was followed to select a target receptor. Later in the paragraph, it states the hypothetical receptor with the greatest exposure potential was identified and this receptor scenario was then selected for quantitative exposure assessment. Is this hypothetical receptor the same as the target receptor? If so, please use the same terms because the use of different terms can be confusing.

EPA Concurs. Closed NO BACKCHECK REQUIRED

52 Section 3.1.4.1 Kiefer Last sentence: "…..then between these two receptors, the farmer would be selected for quantification." suggest exchanging "would be" for "was" so tense is consistent.


53Section 3.1.4.2 Kiefer

Recommend exchanging "would be" and 'would still" with "was" and "was still" so tense is consistent Closed NO BACKCHECK REQUIRED

54 Section 3.1.4.3 Kiefer Recommend exchanging "will be" for "was" so tense is consistent. Closed NO BACKCHECK REQUIRED

55 Section 3.1.5.1 Kiefer States that the only current plausible on-property receptors include a remediation worker. Table ES-1 and Table 13 don't list a remediation worker. Please add to Table ES-1 and Table 13.

EPA will have PRPS explain why current on site exposure scenario and not add remediation worker to Tables. USACE concurs.

States electrical panel is within area 2 and electricitan periodically visit. Agree this is minor exposure; however, shouldn't it be addressed? Paragraph 5 states only OU1 plausible receptors are remediation workers.

NOV 2017 VERSION OF BLRA ADDRESSES WHY THESE UTILITY WORKERS WERE NOT INCLUDED FOR EXPOSURE. COMMENT CLOSED.

56 Section 3.1.5.1 KieferFirst paragraph, last sentence: "and deed restricted". In the previous section, the term "land use restrictions" is used. These are different terms for the same thing. Recommend clarifying that what land use restrictions are stated in the deed.

EPA Concurs (not just editorial). EPA to talk to EPA OC before responding.


57 Section 3.1.5.1.1 Speckin Under the Current Grounds Keeper Scenario there is no mention of inhalation of radon being an exposure route. EPA concurs Closed NO BACKCHECK REQUIRED

58 Section 3.1.5.1.1 Kiefer What is the three maintenance events per year based upon? Please state. EPA concurs. Closed NO BACKCHECK REQUIRED

59 Section 3.1.5.1.1 Twigg

The exposure times may not be conservative enough for a baseline risk assessment without further details. For example, provide details on any interviews with the actual four-person crew that maintains the 130 acres outside if OU-1. If a member of the crew uses a line trimmer (e.g., weedeater) along the entire fenceline surrounding Areas 1 and 2 (approximately 7,000 linear feet of fence), that person would spend much more than 2-3 minutes within 2 meters of the fence. Also, if the crew mows parallel to the fence, the person mowing right along the fence would spend more than 2-3 minutes within 2 meters of the fence, unless a large tractor was used.

EPA concurs better justification is needed. All of these EPCs are from on site data from Area 1. When plug into PRG, it doesn't allow you to have a receptor adjacent to the gamma source. When plug in, it simulates 2-3 min on top of source. It makes sense, but it needs to be added to text. EPA belives this is not representative. Not sure how EPA will respond yet - will discuss with Stuart.

Closed - exposure time revised in accordance with comment. NO BACKCHECK REQUIRED

60 Section 3.1.5.1.2 Kiefer

Why not just assume exposure 1 hr/day adjacent to the fence so that you have a conservative scenario? I'm not sure that the ratio of exposure and area for a commercial building user is as applicable as it is to a grounds keeper. For a current commercial worker, wouldn't the most plausible current exposure scenario be standing outside by the fence to smoke during a 1-hr lunch break or several small breaks throughout the day?

EPA concurs that exposure times are not repreasentatives and justified. EPA believes how they are using PRGs overestimate risk.

Closed - addressed in 3.1.5.2.1 NO BACKCHECK REQUIRED

61 Section 3.1.5.2, 3rd paragraph

KieferThe gas utility worker that reads the gas meter that is within the fenced area of OU1 Area 1 is also a receptor. Even though the exposure is minimal, the utility worker is not monitored like the remediation workers and recommend this scenario be discussed in this risk assessment.

same as #17. Closed NO BACKCHECK REQUIRED

62 Section 3.1.5.2.1 pg. 54 (pdf)

J. Donakowski Typo: assume "Future grounds keepers at Landfill" should be "Future grounds keepers at the Landfill"Editorial - not passing editorial along. USACE is fine with that.


63 Section 3.1.5.2.2 Kiefer 3rd paragraph: Recommend removing the word "hypothetical" from the first sentence and change last sentence to "All current potential off-property exposure scenarios……"

Comment Withdrawn. Withdrawn NO BACKCHECK REQUIRED

64 Section 3.1.5.2.1 Kiefer Recommend you state what the maintenance event frequency and hours is based upon. EPA Concurs Closed NO BACKCHECK REQUIRED

As written, it sounds like they are still doing this work. Tense is important because they have already done this.

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65 Section 3.1.5.3, pg. 47 RankinsA future off-property farmer is not evaluated for consumption of homegrown produce or meat/milk. Assuming that over time, there could be an accumulation of contaminants in soil from continuous air deposition over time, it may be prudent to demonstrate that this will not result in health risks to the off-property farmer over the course of a lifetime.

EPA concurs that off property famer has potential for homegrown produce would be impacted. USACE: Resrad can do this. Expect exposure would be small.

In the June 2017 BLRA, 1,000-year future landfill and off-property scenarios have been added for evaluation that were not evaluated in the October 2016 BLRA. According to Section 3.1 of the revised document, the difference between the future and 1,000-year future scenarios seems to be that land use controls are maintained under the future scenarios, but that controls could be lost under the 1,000-year future scenario. It is reasonable to assume that off-property resident farmers could be exposed via to dust inhalation, radon inhalation, and direct radiation from submersion under the 1,000-year future scenario, as shown in Table 13, due to the assumed loss of controls (e.g., breakdown/degradation of the non-combustible covers in Areas 1 and 2). These off-property exposures are evaluated in the June 2017 BLRA and were previously evaluated in the October 2016 BLRA for the future farmer, though not under the 1,000-year future scenario, which was only developd for the June 2017 BLRA. However, in the June 2017 BLRA, off-property farmer exposures via soil ingestion and consumption of homegrown produce and beef/milk pathways potentially affected by aerial deposition of windblown dust resulting from the wind erosion of potentially exposed RIM at OU1 over time, are still not addressed, even under the 1,000-year scenario. Pathways and EPA PRG equations are presented in Appendix C (see "Farmer Soil") for numerous food sources potentially contaminated by soil. It is believed that at minimum, that future soil concentrations from air deposition of non-radon COPCs could be modeled to downwind, off-property areas, which in turn could be used to determine EPCs for the off-property farmer soil ingestion pathway. Even without soil ingestion, Tables 44 and 47 show that the off-property North and West areas, respectively, are exhibiting cancer risks greater than 1E-04 for the farmer. Perhaps once calculated, at a minimum, the soil ingestion results could be used to make qualitative inferences regarding off-property farmer exposures via the homegrown food consumption pathways, though it would best that the latter also be quantitiatively modeled and assessed. Off-property soil ingestion and homegrown food consumption should be added as potentially complete pathways for the farmer in Table 13 and addressed. If the pathways are not going to be evaluated, then rationale should be provided in Table 13 and the associated text, and/or in the Uncertainty Assessment (Section 6). Evaluation of soil ingestion and homegrown food consumption by off-property farmers under the 1,000-year scenarios, could yield results/information that could be useful in facilitating decision-making amongst the stakeholders.


66

DATA SOURCES FOR CONSTITUENT

CONCENTRATIONS, pg. 16, Section 3.2

EPC's, pf. 47

Rankins

It is not clear what data set(s) have been used to generate the UCL95 EPC values. Comparison of the BLRA data tables vs. database data reveal the removal of some data points when calculating UCL95 EPC values. Further clarification of why some of the maximum values were not used would be helpful. For example, Table 10 list the Th-230 range of detection, Area 2 for all soil depths of "0.182-57300 pCi/g" yet there are 4 other Th-230 at higher values and a max value of 1,470,000 pCi/g although they are "J+" flagged but no "R" marker for data validation. Are these part of the 23 that were still undergoing evaluation and excluded from the data set?

addressed in comment xxxx

Previous comments were made regarding the need for transparency relative to data sets used. A better explanation of the data used in the June 2017 BLRA has been provided in Section 2.1 and Appendix D. Table D-1 shows all of the data for each COPC, for each area (i.e., Area 1, Area 2, and Buffer Zone), sorted from highest to lowest concentrations, for surface and subsurface soils. Also included are the ProUCL calculations for EPC determinations. In the case cited by the comment regarding the range of concentrations reported for Th-230 in Area 2, Table 9 now shows the range of surface detections to be 0.82 - 29,200 pCi/g, and Table 10 shows the range of detections from all depths to be 0.18 - 38,300 pCi/g. Checking against Appendix D, Table D-1 shows surface soil Th-230 in Area 2 to range from 0.82 - 29,200 pCi/g. Table D-1 also shows Area 2 Th-230 from all depths to range from 0.18 - 38,300 pCi/g. Therefore, at least for Th-230, Appendix D data seem to agree with the summary statistics tables (Tables 9 and 10) in the text. The elimination of four higher Th-230 results cited by the comment, which were collected recently in January 2016 (per the available spreadsheets not included in the document), as well as the exclusion of data for other COPCs prior to EPC calculations, does not seem to be addressed in specific case by case detail in the June 2017 BLRA. Generally though, Section 2.1 discusses the use of data usability evaluations and eliminations of statistical outliers as reasons for data exclusions. This section does state: "If specific data were not considered to be representative of OU1, the individual database records involved were annotated to reflect this decision and those individual records were either modified or labeled as unused in the final RI database. Details of this evaluation process and its findings are described in more detail in the revised RI Addendum (2017), Appendix D-12." However, upon review of Appendix D of the June BLRA version provided, no Appendix D-12 could be found. Only the


67 Section 3.2.1 KieferParagraph 5 states that Table 17 contains the same information for material that has aged 100 years or longer. Shouldn't we be looking at the equilibrium of the radionuclides that are expected to be in equilibrium with the original radionuclide for a period of 1000 years or longer, since that is the assessment period? or is it the same?

EPA Concurs it needs to be corrected. Closed - it has been corrected NO BACKCHECK REQUIRED

68 Section 3.2.3 Kiefer 2nd Sentence - please state sentence clearly - as written, it is hard to understand what is trying to be conveyed. EPA Concurs - needs clarity. Closed NO BACKCHECK REQUIRED

69 Section 3.2.5 KieferFirst paragraph, recommend deleting the first paragraph and revising second paragraph to state, "Air exposure point concentrations were determined using Lake Environmental's AERMOD-View….." First paragraph doesn't appear to have any bearing on the need to do this calculation.

EPA Concurs Closed NO BACKCHECK REQUIRED

70Section 3.2.5 1st

bullet Kiefer This area is also applicable to current and future on-site utility workers (ex: gas utility meter reader) Withdraw comment. Withdrawn NO BACKCHECK REQUIRED

71 Section 3.2.5 Kiefer First paragraph after bullets: PM 2.5 please spell out "particulate matter" and label the 2.5 micrometers.Editorial - not passing editorial along. USACE is fine with that.


72 Section 3.2.5, last 3 paragraphs

Kiefer Should these 3 paragraphs be included in the Uncertainties section and not here?

EPA Concurs. Will also want them to have more discussion earlier on so it's clear from beginning where radon risks are coming from. EPA has other issues with these paragraphs, so looking more into them.

Last paragraph is about uncertainties. Recommend it removed as this dicsussion is also included in the uncertainties sectionCOMMENT IS EDITORIAL AND WHILE IT WOULD LEND ITSELF TO A MORE STRUCTURED REPORT, IT DOES NOT CHANGE THE OUTCOME, THEREFORE, THIS COMMENT IS CLOSED.

73 Tables 14 & 15, pgs. 55 - 58 (report)

Rankins

The unit presented for inhalation rate (m3/h) does not reflect the value of 60 presented for the commercial building user and the grounds keeper. An inhalation rate of 60 m3/h is too high for any human receptor. Footnote k indicates that the value is based on the default worker inhalation rate of 2.5 m3/h found in EPA's online PRG Calculator. The actual inhalation rate should be 60 m3/day if based on the following conversion: IRA (m 3 /day) = 2.5 m 3 /h x 24 h/day . Therefore, the value of 60 should be in units of m3/day. The correct units for this value should be presented in the table or as part of footnote k.

EPA Concurs. Closed. The suggested units change for the inhalation rates presented in in Tables 14 and 15, from m3/hr to m3/day, has been

made.NO BACKCHECK REQUIRED

74 Tables 22 & 23 Kiefer ND readings have a footnote "b", which states "no data available". ND is typically used as an abbreviation for "non-detect". Were there truly no data available or is this data non detect?

EPA Concurs. Will get clarifiction.Some info in these tables is listed as ND, which is now defined below the table as Non Detect. However, some of these ND's also have footnote d associated with them, which indicates there is no data. How can the data be Non Detect if there is no data?

THE GENERAL COMMENT HAS BEEN CORRECTED. COMMENT CLOSED.

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75 Table 24 KieferRecommend adding reference to Figure 5 so locations can be easily identified. Also, text in section 3.2.5 states Table 24 includes future exposure point concentrations for particulate and radon. Table 24 is labeled as future particulate air concentrations. Recommend changing either text or table title to be consistent.

EPA Concurs Closed. Reference to Figure 6 added to text in 3.2.5, Appropriate reference in Section 3.2.5 has been fixed. NO BACKCHECK REQUIRED

76 Table 25 pg.74 (pdf) J. DonakowskiThe footenote to this table states the average annual windspeed is 4.6 m/s. In Appendix A this value is given as 4.1 m/s. Please clarify/justify

EPA Concurs Closed: Footnote updated to 4.1 m/s NO BACKCHECK REQUIRED

77 Figure 4, p.67 (report) SpeckinThe conceptual model is not very legible due to a combination of text size and quality. It is recommended it be enlarged to make it more legible.

EPA Concurs Closed. NO BACKCHECK REQUIRED

78 Figure 5, page 68 (report)

Speckin Recommend this figure be flipped 180 degrees USACE withdraws comment. (Birdseye view from north to show offsite receptor properties).

Withdrawn NO BACKCHECK REQUIRED

79 Section 4.2 Kiefer States these chemicals are most prevalent in OU1. Are these chemicals included because they were prevalent or because of their concentration? Please clarify.

EPA concurs - not sure why some chemicals have been cited and others arent. Most of the text in 4.2 may not belong.

Closed. There is no more section 4.2 in report. NO BACKCHECK REQUIRED

80 Section 4.2.19, Page 92 (pdf)

J. Donakowski

The statement is made "The RfD for soluble uranium salts, 0.003 mg/kg/d, is used, although soluble forms of uranium are not expected to be found at the Landfill."Per the RSL user's guide -"Uranium Soluble Salts" uses the IRIS oral RfD of 3E-03 mg/kg-day. For the insoluble salts of Uranium, the oral RfD of 6E-04 mg/kg-day may be used from the Federal Register (PDF), Thursday December 7, 2000. Part II, Environmental Protection Agency. 40 CFR Parts 9, 141, and 142 - National Primary Drinking Water Regulations; Radionuclides; Final Rule. p 76713.

Recommend the RPs consider the use of an oral RfD of 6E-4 mg/kg/day for insoluble salts of uranium, or discuss why this value is not appropriate for use in this risk assessment."

EPA will pass along comment, but it will be a memo from HQUSEPA to use MRLs.

Discussed on page 167, defer to EPA on whether this is handled appropriatlyDUPLICATE COMMENT (RANKINS COMMENT #80). CLOSE THIS COMMENT.

81 Table 26 pg. 94 (pdf) J. Donakowski In "Note" add the date the website was accessed, as slope factors values are subject to revision and updates EPA Concur: Closed: PRG calculator accessed dates added NO BACKCHECK REQUIRED

82 5.1.1.1 pg. 98 (pdf) J. DonakowskiIn Equations 5-1, 5-2, and 5-3 it appears that "·" is used to denote multiplication, while in Equation 5-4 an "x" is used. Please ensure that the document is consistent in use of symbols for operations.



83 Section 5.2 Risk Calculations

Rankins

Recommend consideration be given to including the assumption that land use restrictions will fail in the future and to including exposure scenarios where a commercial worker and resident will have direct exposure on Area 1 and 2. Failure of a land use restriction over a 1000 year period is a reasonable assumption. USACE utilized RESRAD model (Version 7.2) to estimate of on-site incremental cancer risks to hypothetical receptors assumed to be in Area 2. The purpose of this effort was to maximize information that could be useful for future decision-making when including the assumption that land use restrictions will fail in the future. The scenarios evaluated by USACE included the future landfill groundskeeper, a future commercial building user, and a hypothetical resident. All scenarios were evaluated under assumed conditions that included both the presence and absence of the non-combustible cover. Depending on the cover scenario, exposure routes generally included soil ingestion, dust inhalation, external radiation, and radon. When selecting RESRAD model inputs for the evaluations, USACE attempted to use similar exposure assumptions used in the BLRA (Table 15); however, other inputs, such as assumptions regarding the cover and hydrological parameters were based on estimates and USACE experience with the St. Louis FUSRAP sites. The RESRAD results showed that all receptor scenarios exceeded the upper limit of EPA's target risk range, with the maximum total risks occurring in 1,000 years; however, the key result seems to be that radon is the predominant pathway driving the cancer risks for all scenarios. When the radon pathway is activated in RESRAD, the radon pathway contributes most of the risk. When the radon pathway is suppressed in RESRAD, the risk is driven by external radiation, with Rn-222 as the main risk contributor (~90% or more of the risk) from among all radionuclides (i.e., parents and daughters). In contrast, the BLRA results generated using EPA’s web-based radiological PRG calculator show Ra-226 (+8 daughters) and Th-230 to be the primary and secondary risk contributors respectively, due to the external radiation pathway, with radon being an insignificant risk contributor (per Tables 37, 39, and 40). Differences in the model inputs, along with calculation methods used to estimate radon flux could be significant factors contributing to the differences in results, but perhaps the information provided could be useful for future considerations. Attached are the RESRAD risk and dose outputs (MS Word files), from which the summary table (RESRAD Risk and Dose Summary sheet) is generated. Please note that the scenario numbers corresponding to those in the summary table are indicated immediately after the receptor in each filename. Also, the graphics are included on the last pages of each of the attached outputs. At the end of each dose output is the following plot: Dose for All Nuclides Summed and All Pathways Summed. At the end of each risk output are the following plots: Excess Cancer Risk for All Nuclides Summed and All Pathways Summed, Excess Cancer Risk for Th-230 with Ingrowth Progeny and All Pathways Summed, Excess Cancer Risk for Th-230 Component Pathways Excess Cancer Risk for Ra-226 with Ingrowth Progeny and All


84 Risk Calculations Rankins

Recommend consideration be given to utilizing RESRAD model (Version 7.2) either in place of or as supplemental verification of the EPA PRG calculator results. As a separate check of the risk characterization conducted in the BLRA, USACE applied the RESRAD model (Version 7.2) to estimate incremental cancer risks to future off-site receptors utilizing similar inputs. The results indicated similar results to the PRG calculator results in the BLRA for the future groundskeeper, future commercial building user, and future resident receptors. Use of RESRAD could provide the verification of PRG calculator results on all exposure scenarios and provides more transparency on what goes into those calculations. Additionally, it would allow for a singular government approach to how radiation contamination is addressed in the St. Louis area.


85 Risk Calculations Rankins Recommend risk and air modeling calculations presented in one location as an appendix to the BLRA Report. Editorial - not passing editorial along. USACE is fine with that. EPA is ok with separate air modeling from risk. USACE is ok with this.


EPA has to use PRGs. Issues with PRG. Recommendation to use Resrad and one-gov't approach is not lost on EPA. Would USACE run this in resrad as separate deliverable to resrad as separate deliverable to EPA? USACE: yes, recommend USACE do this as a sanity check. We've run some and had similar results, which is positive. This is a second check since the risk numbers drive remediation. EPA concern : Does USACE feel they can comfortably set up RME scenarios so this is this an apples to apples comparison? USACE: biggest difference is how resrad and PRG calculator treat radon. EPA wants to continue to discuss possibly using resrad as check. EPA will not ask PRPs to do this. USACE concurs. Note that these runs will need to be done again. USACE suggests future utility and resident scenarios be done so PRPs have data to help evaluate a partial removal remedy and if the site could ever be delisted. EPA guidance doesnt require full evaluation of this receptor because there shouldn't be a resident on this site ever again. Therefore the value it brings is not worthwhile. Even if removal all RIM, it is not appropriate to build a house on the property. EPA considering to qualitativey discuss this. EPA considering this further and will send out once response crafted and we can discuss further.

The June 2017 BLRA does still not evaluate this receptor scenario. The suggestion by USACE to use RESRAD as a sanity check of the calculations performed using the EPA's PRG calculator, is being considered by EPA as a separate deliverableand has been discussed, but at this point, it still seems to be undecided. Also, given that the June 2017 BLRA has now added the 1,000-year future scenarios, it seems reasonable to evaluate an on-site suburban resident living on the Buffer Area (Areas 1 and 2 not likely to be rezoned residential in the near term), assuming that controls have been lost. This could simply help to maximize the information avaialble to decision-makers regarding a preferred/selected remedy.

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86 Section 5.2.1 J. Donakowski

Are there currently activities occurring at the Buffer Zone property? It appears that no risk evaluation for current receptors was performed for this area, and there does not appear to be any information regarding whether or not non-combustible cover was placed in this area. Given that, could resuspension of material from the Buffer zone property contribute to inhalation dose to current On Property , On Site, or Off Property receptors?

Closed: Buffer zone receptor risks evaluated NO BACKCHECK REQUIRED

87 Section 5.2.1 and 5.3.1 and subsections

Kiefer Please remove "Hypothetical" from the title of each subsection. Also, please remove "CERCLA" from the term "CERCLA risks". It's a calculated risk that is compared to the CERCLA acceptable risk range.

Editorial for hypothetical - but will pass along CERCLA risk part.

Closed. NO BACKCHECK REQUIRED

88 Section 5.2.1.2 pg. 102 J. DonakowskiThe statement is made "The calculated risk from all COPCs is 2.31E-6. This risk is below the EPA target risk range of 10E-6 to 10E-4." Please clarify to state "within the risk range"

Closed. NO BACKCHECK REQUIRED

89 Table 14, pg. 55 Rankins Recommend that incidental ingestion be considered a pathway

EPA sending comment to put in RAGS table format so it will be clear what is being done. Wont' be passing comment for PRPs to consider current incidental ingestion not being covered because Non combustible cover (NCC) is there. USACE is ok with that. Tell PRPs to qualitatively evaluatae this. RESRAD is one way we coould quantitatively check that.

With the addition of the 1,000-year future scenarios, incidental soil ingestion has been evaluated for the future (1,000 years) outdoor storage yard worker and groundskeeper scenarios based on Sections 3.1.5.3.1 and 3.1.5.3.2, Table 15, Table 37 - 43, in the June 2017 BLRA, and the RAGS Part D tables provided. However, a future (1,000 years) on-site resident should still be consideredhe (at least for the Buffer Area) in the event controls are lost, even though current and expected near-term land use is industrial/commercial. This could be useful for evaluating remedies in the FFS and provide a broader range of information for decision-making. If a quantitative evaluation is not performed, then a qualitative discussion based on the future (1,000 years) outdoor storage yard worker, the risks for whom exceeds 1E-04 in both Areas 1 and 2, could be added. Essentially, it would be expected that the more health/radiosensitive on-site resident scenario would result in even higher cancer/non-cancer risks.


90 Slope Factors, Table 26, pg. 86

Rankins

Recommend consideration be given to evaluating the RESRAD SF's, which are used for USACE's FUSRAP sites in St. Louis. While the SFs do not differ significantly, this would provide a singular government approach to how radiation contamination is addressed in the St. Louis area. See attached comparisons of updated EPA SF's vs. RESRAD SF's utilized on St. Louis FUSRAP sites. The use of RESRAD also provides more transparency on how calculations are derived than the PRG calculator. See attached comparisons of EPA SF's vs RESRAD SF's used for USACE's FUSRAP sites in St. Louis.

EPA has to use SF's in PRGs. Same as 83/84 - tabled, not passing to PRPs as comment. More discussion to follow.

EPA uses radiological slope factors in the PRG calculator based on the most recent updates presented in the attachment to ORNL's 2014 document entitled Calculation of Slope Factors and Dose Coefficients (ORNL/TM-2013/00). These in turn apply decay chain and energy information provided in ICRP 107. The RESRAD model applies the same factors; however, only the radiological SFs and DCFs in the DCFPAK3.02 (Adult) library are currently used for the SLS. Use of the adult factors primarily pertains to the soil ingestion SFs and DCFs. Factors for the other pathways are non-age-specific. Based on Table 26 of the June 2017 BLRA, adult SFs were applied as well. The main difference between the SFs used in the BLRA and those used in DCFPAK3.02 is that in the latter, the RESRAD model applies food ingestion SFs to the soil ingestion pathway, which the USACE has evaluated (in response to a DHSS comment on the Third Five-Year Review) as not being significantly different from application of soil ingestion factors to the soil ingestion pathway. However, applying soil ingestion factors to the soil ingestion pathway in RESRAD requires that a user-modified library be developed. It could be that EPA risk assessors are aware of this minor discrepancy and is more comfortable with using the SFs applied in the PRG calculator, which uses soil ingestion SFs for evaluating the soil ingestion pathway.


91 Tables 30 - 50 Kiefer Recommend spelling out ILCR (Incremental Lifetime Cancer Risk) in title, as applicable Not spelled out anywhere - need to spell out. EPA will send to PRPS.

Closed - acronym removed. NO BACKCHECK REQUIRED

92 Section 6.3 pg. 138 J. Donakowski

While true that the availability of a municipal water supply would likely preclude direct consumption of impacted well water, given than one of the scenarios evaluated was an off-site farmer, it may be reasonable that a farmer would use impacted groundwater to irrigate (and consume) crops grown on site; defer to EPA on whether groundwater use for crop irrigation is a potentially complete pathway, or whether this would be more appropriately evaluated as part of OU 3.

Future groundwater impacts and groundwater use will be addressed in OU 3 documents. EPA has made significant comments on groundwater in the initial RI.

Groundwater restrictions and further detail as part of OU3 discussed. Still some questions over whether crop ingestion is considered a viable pathway for this OU.

93 Section 6.4 pg. 140 J. Donakowski

Recommend revising/clarifying the statement regarding radon flux or providing additional information. While true median radon flux rates reported in the 2000 RI are below 1.0 pCi/m2/s, values in the hundreds of pCi/m2/s were observed in discrete areas, and simple averaging suggests that site wide values may be somewhat higher than "a few pCi/m2/s". This seems to differ from the flux measurements discussed in Section A.2.3. The measurements reported in Table A.2 appear considerably lower than historic data. Are the radon flux values from 2000 RI (See RI Section 7.1.1.1.1 and Table 7-1) now no longer being used? Please clarify.

Flux data has been recollected since installation of the non-combustable cover. What data is being used will be clarified. EPA does not believe "credit" should be taken for the non-combustible cover. One consideration would be to use an area weighted average of the previous data set.

Closed: Clarification provided NO BACKCHECK REQUIRED

94 Appendix A.2.3 pg. 159 J. Donakowski

MARLAP is a guidance document and not a form of laboratory accreditation. Indeed, much of the MARLAP DQOs are predicated on determining acceptable errors at established DCGLs, which commercial labs generally cannot do without significant project specific involvement. Please clarify how a lab demonstrates compliance with MARLAP and/or consider rewording/revising/removing.

Concur, MARLAP is not accredidation. This section will be expanded and clarified.

Closed: Revision made on page 6 of appendix A NO BACKCHECK REQUIRED

95 Table A.3 pg. 162 J. Donakowski In previous assessments, the RAECOM model has been used to model projected radon flux, resulting predicted flux values above those presented here; defer to EPA on whether the proposed interpolation/scaling is appropriate.

Given that it is reasonable to assume that radon flux will scale with Ra-226, interpolation is reasonable. This comment will not be passed on.


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96 A2.14 pg 184 (pdf) J. Donakowski

The radon progeny ingrowth appears to assume that radon daughters in grow and that the radon flight time from the source of release is the same as the bulk velocity of air, stated here as 4.1 m/s (see comment re: Table 25 value of 4.6 m/s). EPA's CAP-88 code utilizes higher equilibrium factor assumptions for near site receptors (see Cap88 User's Guide Section 12.1.9). Given that the calculated Rn-222:Bi-214/Pi-214 equilibrium fractions provided in this section do not begin to approach those presented in Cap88 until a distance of about 5,000 m. Indeed, the caulcated tables provided show radon in 100% equilibrium with it's progeny after about four hours. Radon is nearly never seen in 100% equilibrium in outdoor air, suggesting that the Batemay decay approach utilized in this analysis may be over simplifying radon transport and daughter ingrowth in nature; defer to EPA on whether Cap88 provided equilibrium values may be better suited for analyze risk for near site receptors than the simple Bateman decay equations presented in this section.

Jon: Is EPA going to utilize CAP 88 model? EPA not sure if wil use CAP 88 but wants to discuss this bc its not clear in BLRA what PRPs have done. USACE thinks CAP-88 is better suited to determine near site receptors than what PRPs have presented. CAP 88 more realistic environment because how radon and particulates are transported. Jough and Tom to continue discussion.

A comment regarding explaining the airspeed of radon gas vs. soil, limitations of Aermod in regard to gas transport, and the conservatism of uncertainty associated with the equilibrium fractions will be passed on.

Closed: Use of CO as surrogate for radon in AERMOD provided. NO BACKCHECK REQUIRED

97 Entire Document TwiggUse of punctuation in bullet lists is inconsistent throughout report (e.g., some bullets end with a semicolon, some end with a period, and some don't end with any punctuation). Please revise accordingly.



10

Draft Final Baseline Risk Assessment Report June 22, 2017

Comment #Reference: Section/

Paragraph/ AppendixCommentor Comment

EPA Comment Letted for the Jun 2017 BLRA (comments dated

10/10/17)Backcheck against Nov 2017 BLRA

1 General J. DonakowskiMany editorial comments are related to a lack of spacing between words. Specific examples are given as additional comments, but these comments do not capture every instance of this issue.

Editorial - Not passed PRPs (per previous EPA discussions)

NO BACKCHECK REQUIRED

2Executive Summary

Page 1J. Donakowski For discussion - Does calling out the fractional contribution of radon-222 to risk add value here and elsewhere?

EPA thought there was some value added by leaving the % radon contribution in the table so the comment wasn't passed on. (email from Hooper to Kiefer 12/8/17)


3 Figure 3 RankinsThere are two figure numbers on this figure - "Figure 3-5" appears in the figure, and "Figure 3" appears below the figure. It should be just "Figure 3".

General Comment #7All changes have been made to the figures in the text where needed; therefore, this comment has been addressed in the Nov 2017 BLRA.

4 Section 1.1.1 TwiggIdentifying any existing data gaps is stated as one of the specific objectives (4th bullet) of the Baseline Risk Assessment; however, the report does not discuss this issue further. Please clarify whether or not any data gaps were identified, and if they were, please elaborate any data gap(s) and potential impacts to the risk assessment.

Sect 1, Comment #6Data gaps discussed in Secs. 3.1.5.3, 3.3.2, 3.2.4, 4, and 6. COMPONENT INCORPORATED. CLOSED

5 Section 2.1 Page 14 J. DonakowskiIt would be helpful to include a brief discussion of how many data points were modified or removed as part of this analysis (i.e. less than 1%, less than 5%, etc.)

Sect 2, Comment #8Helpful, but not required. Does not technically change BLRA or outcome. CLOSE Comment.

6 Section 2.3.1 Rankins

The last paragraph of the section states that: "Calcium, copper, fluoride, iron, manganese, magnesium, potassium, selenium, sodium, and zinc were screened out based on the UTLDI comparison." Typically, the use of values such as UTLDIs, or even U.S. FDA recommended daily allownces (RDAs) is applied to the screening of macronutrients (e.g., calcium, magnesium, potassium, and sodium). The macronutrients are usually present naturally in the environment at high concentrations and exert low toxicities. Becasue of their high abundance and low toxicities, there are no cancer/non-cancer toxicity criteria available from EPA for assessing risks/HIs. The other inorganics mentioned in the last paragraph of Section 2.3.1 are micronutrients and naturally present at low concentrations in the environment. Becasue of their higher toxicities (i.e., relative to the macronutrients), EPA has developed RSLs for most of these elements. In order to eliminate these elements from quantitative risk evaluations, it should be proven that they are within background levels and are not site-related. Otherwise, the screening of these elements should be conducted based on RSL comparisons. Please rescreen all micronutrients listed by Region 8 (chromium, cobalt, iron, manganese, molybdenum, phosphorus, selenium, and zinc) based on RSL comparisons, if they cannot be proven to be non-site-related and within background.

Sect 2, Comment #10 (?)

Section 2, Comment 10 of the EPA RTCs seems to cover this comment in more general terms. In Table 5 of the November 2017 BLRA, micro- and macronutrients were compared to EPA's route-specific SLs and RSLs, when available, in addition to the nutrient screening levels that were derived based on FDA UTLDIs. However, the BLRA continues to apply the nutrient screening levels as the primary screening for the nutrients. Table 5 shows that for copper, iron, and manganese, the maximum screening concentrations exceed the corresponding RSLs, but are less than the nutrient screening level. All three metals were screened out because they were less than the nutrient screening levels, even though they exceeded the risk/toxicity-based RSLs. Also, there are no background values/comparisons presented in Table 5. Therefore, this comment has not been addressed. (COMMENT NOT ADDRESSED, STILL RELIES ON UTLDIs)

West Lake Landfill Superfund Site

USACE Comments as of 8/16/17 and backcheck

11

7Sections 2.3.1 and

2.3.2Rankins

The last sentence of the second paragraph of Section 2.3.1 states that the May 2016 RSLs were used in the screening process, when availalble. Since Section 2.3.1 discusses nutrients, it was presumed that RSLs were used in Table 6. Please refer to the RSLs being in Table 5 for better clarity. Second, please note that the most recent RSL tables were published by EPA in June 2017. Relevent to the RSL discussion, Section 2.3.2 discusses exosure route-specific "screening values" for EPA's "default worker" scenario. This entire discussion needs clarification. First please indicate that the route-specific screening values are actually the route-specific "screening levels" (SL) that are presented in EPA's RSL tables. The term "SL" is consistent with terminology used in EPA's RSL tables and should be applied throughout the text. Also, please clarify that "EPA's default worker" is actually the composite worker who is a long-term employee who mainly spends most of the work day performing outdoor maintenance activities (e.g., moderlate-level digging, landscaping, etc.). The route-specific SLs are presented in Table 5, but there is no reference to Table 5 in Section 2.3.2. Please add a reference to Table 5 in this section. Finally, in the Table 5 column headers, replace Ingestion Screening Value with Ingestion Screening Level (or SL), for consistency with EPA's RSL tables. Likewise, replace Dermal Screening Value with Dermal SL and Inhalation Screening Value with Inhalation SL. These requested changes are meant to bring a better understanding and perspective to the reader as to the source and underlying exposure assumptions that are the basis of the SLs.

Sect 2, Comment #11

First & second sentences of comment: the statement regarding the May 2016 RSLs has been removed from the paragraph/section. Third sentence: The date citations of the RSLs has been replaced with the "EPA 2017a" reference citation. The changes suggested through the remainder of the comment have not been incorprated into the Nov 2017 BLRA.

8 Tables 1 - 12 J. Donakowski

Values for some radionuclides appear suspect or highly suspect based on their short half lives and the reported parent concentrations. For example, the average value of 200 pCi/g for Ra-224 given in Table 7 is highly suspect given that its parent is present at a concentartion ~150 times lower and no other thorium series nuclides appear to be present at concentrations approaching this level (with the possible exception of a Th-232 upper range value of 515 pCi/g given). Please clarify if this data is believed to be accurate, whether it was included for completness but qualified or rejected, and whether or not this data has any impact on the risk assessment as a significant contributer to risk. Specific examples are given as additional comments, but these comments may not capture every instance of this potential issue.

EPA believes a lot of the apparent inconsistencies regarding detection range, averages and UCLs have been corrected and addressed in the Response to Comments (RTC) document; specifically response #3, #8 and #23 which affected many of the tables, for example Tables 7-10. (email from Hooper to Kiefer 12/8/17)

COMMENT NOT ADDRESSED.

9 Tables 1 - 12 J. Donakowski

Many constituents have reported arithemtic means that are outside of the reported range of detections. It is unclear if this is an artifact of the way artithmetic means are being reported in this report, an artifact of the way ProUCL calculates an arithmetic mean, or an error. Please clarify why these instances occur. Specific examples are given as additional comments, but these comments may not capture every instance of this postential issue.

Given that the provided RAGS Part D tables do not cite an artihemtic mean or 95% UCL within the table, but rather reference tables within the BRA document, it is critical to ensure that these values are correct and that appropriate values are being used for the risk assessment.

General Comment #8 ADDRESSED BY FOOTNOTE, COMMENT CLOSED.

10 Table 4 Page 27 J. DonakowskiThe average value of 9.51 for Ra-223 given in Table 4 is suspect given that its parent Ac-227 is present at a concentration ~20 times lower. This may be an artifact of averaging, given the range of detected values cited in Table 7?

Not passed to PRPs. Per Sect 2 Comment 20 of EPA's comments, Table 4 is to be deleted, background concentration column is to be added to Table 1.


11 Tables 4 and 5 RankinsPlease modify the titles of Tables 4 and 5 to indicate that the screenings of radiological and non-radiological constituents, respectively, are applicable to constituents detected across OU1.

Table 4 to be deleted per Sect 2 Comment 20. Table 5 addressed in Sect 2, Comment 21

ADDRESSED, COMMENT CLOSED.

12 Table 5 RankinsIt should be noted that based on the nutrient UTLDI-based screening levels provided in Table 5, the maximum screening concentrations of chromium and cobalt exceed the respective nutrient screening levels.

Sect 2, Comment 21 COMMENT NOT ADDRESSED.

13 Table 5 RankinsThe industrial worker ingestion screening value of 350 mg/kg for uranium (based on a THQ of 0.1) should be updated to EPA's updated (June 2017) ingestion SL of 23 mg/kg (also based on a THQ of 0.1).

Sect 2, Comment 21 ADDRESSED, COMMENT CLOSED.

14 Figure 4 Rankins The X- and Y-axis labels are difficult to read in this figure. Please use larger or clearer graphics for this figure. ---Comment addressed in the Nov 2017 BLRA. COMMENT CLOSED.

15 Table 6 RankinsPlease reword footnote 'b'. The equation shown in the footnote converts the UTLDI from an intake in mg/d to a screening concentration (value) in mg/kg. The nutrient soil screening value is not an intake rate, as is implied by the footnote as currently written.

Comment remains open and needs to be discussed (email from Hooper to Kiefer 12/8/17)

Comment not addressed in the Nov 2017 BLRA. Has comment been addressed in footnote c?

12

16 Table 7 Page 32 J. DonakowskiThe average value of 123 pCi/g for Ra-223 given in Table 7 is suspect given that its parent Ac-227 is present at a concentration ~10 times lower. This may be an artifact of averaging given the range of detectied values cited in this table?

Section 2, Comment 23 (?) no explanantion provided

17 Table 7 Page 32 J. DonakowskiThe average value of 200 pCi/g for Ra-224 given in Table 7 is highly suspect given that its parent is present at a concentartion ~150 times lower and no other thorium series nuclides appear to be present at concentrations approaching this level (with the possible exception of a Th-232 upper range value of 515 given)


18 Table 7 Page 33 J. DonakowskiThe artimetic mean for berylium is higher than the given range of values. The arithmetic mean of mercury, thalium, and 1,4-Dichlorbenze is lower than the given range of values. Please clarify if this is an artifact of the way averages are being evluated/report, an artifact of ProUCL, or an error.

Section 2, Comment 23 (?) comment addressed in footnote. COMMENT CLOSED.

19 Table 8 Page 35 J. DonakowskiThe averave value of Th-227 and Ra-223 given in Table 8 is suspected given that its parent Ac-227 is present at a concentration ~5 - 10 times lower. This may be an artifact of averaging given the ranged of detected values cited in this table?


20 Table 8 Page 35 J. DonakowskiThe average value of 121 pCi/g for Ra-224 given in Table 8 is highly suspect given that its parent is present at a concentartion ~20 times lower and no other thorium series nuclides appear to be present. Section 2, Comment 23 (?) no explanantion provided

21 Table 8 Page 36 J. DonakowskiThe artithmetic mean of dichlorobenze and bezene appear impossible given the range of detetions for the anlaytes listed. Please clarify if this is an artifact of the way averages are being evluated/report, an artifact of ProUCL, or an error.

Section 2, Comment 23 (?) comment addressed in footnote. COMMENT CLOSED.

22 Table 9 Page 38 J. DonakowskiThe averave value of 645 pCi/g Ra-223 given in Table 9 is suspected given that its parent Ac-227 is present at a concentration ~30 times lower. This may be an artifact of averaging given the ranged of detected values cited in this table?


23 Table 9 Page 38 J. DonakowskiThe average value of 913 pCi/g for Ra-224 given in Table 9 is highly suspect given that its parent Th-232 is present at a concentartion ~340 times lower and no other thorium series nuclides appear to be present at concentrations approaching this level


24 Table 9 Page 38 J. DonakowskiThe average value of 221 pCi/g for Ra-224 given in Table 10 is highly suspect given that its parent Th-232 is present at a concentartion ~30 times lower and no other thorium series nuclides appear to be present at concentrations approaching this level (with the possible exception of a Th-232 upper range value of 180 given)


25Table 9 Page 38 and

39J. Donakowski

The artithmetic mean of nearly all non-radionuclides appear impossible given the range of detetions for the anlaytes listed. Many are higher than the range of values, or different when a single value appears to be present within the range. Please clarify if this is an artifact of the way averages are being evluated/report, an artifact of ProUCL, or an error.

Section 2, Comment 23 (?)data appears to have been corrected and addressed in footnote. COMMENT CLOSED.

26 Table 10 Page 41 J. Donakowski Table 10 - See previous comments regarding Ra-223, Ra-224, and Th-227

EPA believes a lot of the apparent inconsistencies regarding detection range, averages and UCLs have been corrected and addressed in the Response to Comments (RTC) document; specifically response #3, #8 and #23 which affected many of the tables, for example Tables 7-10. (email f

Kiefer, Robyn V CIV USARMY CENWK (US) Hooper, Charles A ...Recommend that 2nd sentence be clarified...

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