A L C O A

Alcoa Remediation Management

State Hwy 35 Building 505 P. O. Box 101 Point Comfort. TX 77978 USA Tel: 1 361 987 6607 Fax: 1 361 987 6804

June 9, 2005

Mr. Dion Novak Remedial Project Manager United States Environmental Protection Agency Region V Superfund Division, Mail Code SR-65 77 West Jackson Boulevard Chicago, Illinois 60604-3590

USEPA RECORDS CENTER REGION 5

431542

Re: North Alcoa Site, East St. Louis, IL, Draft Response to Comments, Baseline Human Health Risk Assessment

Dear Mr. Novak:

We have received the agency comments on the draft Baseline Human Health Risk Assessment Report for the North Alcoa Site, East St. Louis, Illinois. To facilitate the review and discussion process, we have replicated the original comment in bold italics, followed by a draft response, and conclude with the proposed action to address the comment and response.

GENERAL COMMENTS

The particulate inhalation pathway is not quantified in IB-3 (all receptors) and in iB-4 a and e (future industrial/commercial worker and recreational receptor) based on the presence of vegetation and wet soils. This pathway should be quantified for the following reasons:

• It is standard method to evaluate the particulate inhalation pathway in a HHRA, regardless of vegetative cover. Region 3 RBCs, Region 9 PRGs, EPA SSLs, lEPA TACO soil remediation objectives all consider the particulate inhalation pathway. The document does not provide sufficient justification to exclude this exposure route for some areas but not all areas of the Site.

• Several of the metals measured in soil are carcinogenic through the inhalation exposure route.

• It is important to remember that the iB-3 property is owned by various individuals, not by the City.

• Or7e cannot be certain that the vegetative cover will remain on the Site and that the soils will remain wet to exclude this exposure route. The vegetative cover can be accounted for in the PEF model and also discussed in the uncertainty analysis. To exclude this exposure route because of a vegetative cover one would have to ensure that this vegetative cover is maintained.

Mr. Dion Novak June 9, 2005 Page 2

Response: The inhalation of particulates pathway will be included for all soil scenarios per EPA's request. ^ \ I,

Action: The inhalation of particulates pathway will be included for all soil scenarios in the revised BHHRA.

SPECIFIC COMMENTS

1. Page ES-2 last par; Page 1-1 last par; Page 1-3 par 2; Section 1.2. As discussed at our meetings, all references to the presumptive remedy (PR) guidance will be moved to the remedial action objectives section of the RI report and ali current and future risks will be presented in this document, in addition, references to risk will include only that the calculated risks are within or not within EPA's risk range, and exclude any language regarding "acceptable" or "unacceptable" risk.

Response: We plan to remove ali discussion related to the Presumptive Remedy from the BHHRA. Potential and likely future receptor scenarios will include 1) the status quo, 2)

_ ' ' \ ^ l^ - ' industrial and commercial development in developable areas in IB-3b, and 3) recreational \ y ( ^ ^ receptors in areas upon completion of various, yet to be determined, remedial action > ^ ^ -{tA^sn alternatives in IB-1, -2, -4a and -4d. Likewise, we will change language that describes risks as ^c?' , acceptable or unacceptable to indicate whether the calculated risks are within or not within )f a/f EPA's risk range.

Action: The text will be revised accordingly.

2. Page ES-4 top par. Please provide the appropriate citation for the ATSDR report.

Response: We will provide the full citation for the ATSDR report.

Action: The text will be revised accordingly.

3. Page 2-2 par 1. Sediment data from IB-4b should be evaluated separately from IB-4a and 4d because it is not clear whether this area is contemplated for the PR remedy procesTs.

Response: Sediment data from IB-4b were evaluated separately in the BHHRA for future recreational scenario. This receptor was assumed to have contact with IB-4a soil and IB-4b surface water and sediment IB-4b sediment was included with IB-4a and IB-4d sediment for the current trespassing scenario. ,,

/5-4/U^ r (C OJ)p i I (MJ^{y r.4yu , , , Action: None proposed. / : . I . ' • J r ^ ^ . J ^ t ^ / l Y P ' P ^ ' ^ ^

4. Page 3-1 Section 3.1.1. Please note that East St. Louis is an environmental justice community.

Response: While the City of East St. Louis may have attributes similar to environmental justice communities, the site is not listed on EPA's Region V website as an NPL or non-NPL environmental justice site (i.e.,

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Mr. Dion Novak June 9, 2005 Pages

http://vwvw.epa.gov/region5superfund/sfd ej/htm/ei sites list.htm#il, and http://www.epa.gov/region5superfund/sfd ej/htm/nonnpl ei sites.htm#il. respectively). ^ ;r

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Demographic information necessary to perform a complete and accurate baseline risk assessment is provided in Section 3.1.1.

z'Action: None proposed.

5. Page 3-4 par 1. Please include a scenario for industrial exposure to groundwater through results from the Upchurch water well.

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Response: We will include an industrial scenario for a worker incidentally contacting groundwater at the Upchurch well in the BHHRA. ""'/ ^ r--

Action: The text will be revised accordingly. <c t ;\>

6. Page 3-4 par 2. Please add the additional information from East St. Louis on ordinance enforceability that was referenced at our meetings. Please also note that a portion of the site is in Alorton, which is not covered by the ESL groundwater ordinance, and as such, does not have any restrictions on groundwater use.

Response: We are following up on this issue and will provide language in the risk assessment i related to the ordinance enforceability. We will also contact the City of Alorton to determine

whether they have any restrictions on groundwater use and the implication this may have on ]'. exposure to compounds in groundwater. Please note that the only portion of the Site located

A/),. -, '•' within Alorton is the southeast corner of the site. This area is upgradient or cross-gradient from the waste materials on site, in contrast to the City of East St. Louis, which is located downgradient ofthe Site.

Action: The text will be revised accordingly. , r f ' i ) ~ ' y ' / ? ' ' / r f

7. Page 3-5 numbered bullets. Please note that ESL also prohibits the use of potable water supply wells (see #2). Please include the results of the calculations for current and future risks from groundwater here.

Response: The text will be revised according to the comment. See response to Specific Comment #5 for additional information. ^ ,

Action: The text will be revised accordingly.

8. Page 3-9 p a r i . Please provide more justification for the conclusions regarding A I the recreational and sports receptors, and future construction receptors discussed here.

M ^ 0 h ^ P ^ ^ ^ Response: This comment will be addressed as we remove discussion of the Presumptive i

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\ 0 1 y ^ Action: No separate action proposed - the comment will be addressed as part of the revisions ^ A-iJOf ^QuAy f j made per Specific Comment #1. ' ^ ^ M j U v

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Mr. Dion Novak June 9, 2005 Page 4

9. Page 3-13 Section 3.2.1. - The text does not provide a basis for excluding this pathway for some areas and not for others, it only describes why off-site particulate migration is not evaluated for some areas in Section 3.1.4.3.

Response: See response to General Comment #1.

f]fM Action: The text will be modified to indicate that inhalation of particulates pathways, although /. likely not significant in some areas, will be added to all scenarios of contact with soil. ''^-'

10. Page 3-14 Section 3.2.1.1.1. As discussed, please evaluate a trespasser scenario to onsite residue. Please also include in the risk summary a discussion of potential exposure to soil amended with gypsum, particularly with respect to the potential FS technology of soil amendments with onsite gypsum.

Response; The BHHRA does include receptors with the potential to contact residue. These are the current trespasser and future recreational receptors of contacting soil (i.e., predominantly residue) IB-1. The BHHRA also addressed gypsum-amended residue

• concentrations in a qualitative manner in the uncertainty section. , - ' , <= . , . .v^ ''< ' ^&J0

Action: None proposed. pf'^^f ' -...-U - k r ^ ^

11. Page 3-16 p a r i . Please outline potential future recreational risk separately for IB-1 and IB-2.

Response: IB-2 was identified separately from IB-1 in the development of the Work Plan simply to acknowledge the differences in chemicals that may be present. From an exposure standpoint and especially when evaluating a future scenario after re-grading and other improvements have been made, IB-1 and IB-2 will be indistinguishable and, as such, we evaluated future exposure at IBs 1 and 2 together. However, in response to this comment and to differentiate the chemical differences between IB-1 (i.e., residue material) and IB-2 (i.e., gypsum material), IB-2 data will be evaluated for hypothetical future industrial and construction scenarios. These scenarios will have greater exposure potential than a casual recreational scenario. . •.

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Action: Hypothetical industrial worker and construction scenarios will be included in the '-'• BHHRA for IB-2. , ^-

12. Page 3-19 Section 3.2.1.4.3. Please provide additional justification for the revised exposure frequency for baseball.

Response: The City of East St. Louis attorney was the source of the information on the length of the baseball season, and this will be indicated in this section.

Action: The City of East St. Louis attorney will be referenced as the source of site-specific f\ r~ information for modifying the exposure frequency of baseball.

13. Page 3-21 Section 3.2.3. Please move the PR discussion to the RAO section of the RI report.

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Mr. Dion Novak June 9, 2005 Page 5

Response: Comment noted and the text, as discussed in Specific Comment #1, will be ^ - / revised.

Action: The text will be revised accordingly.

14. Page 5-2 Section 5.1.2.1 par 2. Please move the PR discussion to the RAO section of the RI report.

Response: Same as previous comment. ^

Action; The text will be revised accordingly.

15. Page 5-3 Section 5.1.2.2. Please move the discussion on deed restrictions to the Ri report.

Response; The text will be revised as part of the general removal of language specific to the -^ Presumptive Remedy.

Action: None proposed.

16. Page 5-4 par 3. Please see First comment regarding "acceptable" and "unacceptable" risks.

Response; See response to Specific Comment #1.

Action: See action for Specific Comment #1.

17. Page 5-5 last full par. Please move this discussion about these potential RAO's to the RI report.

Response: See eariier response related to this topic.

Action; The text will be revised accordingly.

18. Page 5-7 par 4. Please move the last sentence regarding arsenic to the uncertainties section. ^ r

Response; We believe that it is helpful to have this statement in the text to provide context, which is similar to the approach taken at the end of the risk discussion for IBs-4a, 4b, and 4d on the previous page.

Action; None proposed.

19. Page 5-14 IB-2. Please include calculations for potential future risks in this area.

Response; Page 5-14 discusses the potential for off-site migration of particulates to off-site residential areas. Under current conditions, the gypsum material of IB-2 is cementitious and tends to form a crust on the surface. As such, the surface of IB-2 gypsum is not prone to wind

Mr. Dion Novak ,, ^ June 9,2005 \ i r-\ J ^ ^ I .../.. ,

Page 6 , ^.fi/7^- ^ - M "4. ^ / t.' /'

erosion and dispersion. Under future circumstances without remedy implementation, the same conditions would hold. Therefore, no calculations for future risks of off-site migration of particulates are needed in this section.

Action; A statement will be added to the text that there also would be little potential for wind erosion and dispersion of gypsum material under future conditions without remediation.

20. Page 5-19 p a r i . Please provide the correct ratio of total Cr to hexavalent Cr.

Response; We understand that this comment is referring to the ratio of 1:6 hexavalent to total chromium, as was presented in the Baseline Ecological Risk Assessment (BERA). This value is based on the methods of USEPA Region 6 for deriving a TRV for chromium (total) for human health medium-specific screening values, which assumes that the ratio of Cr VI to Cr III in a given environmental sample is 1:6. CrVI is orders of magnitude more toxic than Cr III and because there is only an assumed 6-fold concentration difference between the valence states in a given environmental sample, the toxicity of Cr VI is the driving factor in the development of the TRV for Cr (total). The TRV for Cr (total) is derived by assuming that Cr VI is 1/7 of the concentration of Cr (total) in a given sample; thus the concentration of Cr VI can be considered diluted by a factor of 7 in the Cr (total) concentration. Therefore, increasing the TRV for Cr VI by a factor of 7 provides a TRV protective of both Cr VI and Cr III toxicity by adjusting for the likely concentration of the more toxic Cr VI in the Cr (total) value. (Ref ID 1179). In this case, the TRV for chromium (total) is equal to 7x the chromium VI TRV This ratio will be added to this section ofthe BHHRA, as well.

Action: A discussion of the ratio of 1:6 hexavalent to total chromium will be added to this section.

21. Page 6-2. Please discuss the results of the Phase 2 sampling on previous risk calculations and risk conclusions.

Response; The Phase 2 sampling was conducted to provide data for ecological risk needs. There were no human health Data Quality Objectives for the Phase 2 sampling effort. Because of this, we did not feel it was appropriate to include them in the BHHRA. We did estimate the exposure point concentrations with and without this data and the significance of including them in our already robust data set was inconsequential. Therefore, we did not include them in the /- :-? BHHRA since including them would not change the risk calculations or conclusions. / » ^

Action; None proposed.

22. Page 6-4 par 3. Please discuss potential exposure issues for contact with soils during fill activities.

Response: We did evaluate a potential future construction worker scenario at IB-3 and 4 (at appropriate sub-IBs such as IB-4e) contacting soils during fill activities.

Action: None proposed. C

Mr. Dion Novak June 9, 2005 Page 7

23. Page 8-1 Section 8.0. Please add the reference to the PR guidance for metals in soils.

Response: Since we are removing the all references to the Presumptive Remedy guidance, we will not address this comment per se. ^

Action: None proposed.

24. Table 3.2-1. The chemical specific absorption factors and Kp values used in quantifying intake must be provided.

Response: Kp and absorption factors will be listed along with the chemical-specific properties and toxicity table.

Action; The tables will be changed accordingly.

25. Appendix C tables. The RME ingestion route for trespasser and recreational receptor are calculated with a different ingestion rate than presented in the workplan. Soil contact, skin adherence and soil ingestion are a function of activity and are generally unrelated to time. Please correct this discrepancy and also include calculations for future risk.

Response: While we agree that soil contact and skin adherence factors can be considered to be functions of activities and not necessarily time, soil ingestion rates are related to time. Soil ingestion rates are typically presented on a daily basis. If a receptor is assumed to be present at a site for only a small proportion of the day (2 hr out of an entire day for both trespasser and recreational RME scenarios), then it is reasonable that the incidental ingestion rate of soil assumed for the time the receptor is at the site be adjusted down from the daily rate. It is very conservative to assume that the entire day's soil ingestion will occur during the 2 hours the receptor is on the site. The BHHRA did not adjust dennal exposure factors for these receptors, but did use an ingestion rate that is equivalent to the residential daily rate divided by 4 to account for the small proportion of the day the receptor is on site. That this adjustment was not reflected in the Work Plan was an oversight. In response to this comment the dose and risk/hazard calculations for the incidental ingestion of soil will be revised using the ingestion rates presented in the Work Plan. However, the conservatism of this approach will be addressed in the uncertainty section, as well.

Action: The risk calculations will be revised to reflect this comment.

While it was not specifically addressed in EPA's comments on the BHHRA, the radionuclide data, collected as part of the RI and based on comments received on the RI, will be included in the chemical of potential concern identification section of the revised BHHRA.

Mr. Dion Novak June 9, 2005 Pages

Please contact me at 361-987-6607 if you have any questions about these responses

Sincerely,

Ronald W. Weddell ^ ^ Remediation Business Group Manager Alcoa Inc.

cc: Greg Pfeifer, Alcoa, Inc. Michael Wagner, Hinshaw and Culbertson Rick Lanham, Illinois EPA (Springfield) Tom Miller, Illinois EPA (Collinsville) Renny DeVille, Harris, DeVille & Associates, Inc. City Manager, City of East St. Louis Bryan McCulley, MFG, Inc.