Barr Engineering Company 8300 Norman Center Drive Minneapolis. MN 55437-1026 Phone: (612)832-2600 Fax: (612)835-0186 June 30, 1993 Mr. William Bolen U.S. Environmental Protection Agency Region V Waste Management Division IL/IN Remedial Response Branch HSRL-6J 77 West Jackson Boulevard Chicago, XL 60604 Re: Waukegan Manufactured Gas and Coke Plant (WCP) Site Response to Comments on the April 1993 Phase I Technical Memorandum Dear Mr. Bolen: On behalf of Mr. Patrick Doyle of North Shore Gas Company, we are submitting this response to your letter of May 21, 1993, which transmitted U.S. Environmental Protection Agency (U.S. EPA) and Illinois Environmental Protection Agency (IEPA) comments on the April 1993 RI/FS Phase I Technical Memorandum, Waukegan Manufactured Gas and Coke Plant Site, Waukegan, Illinois. This letter is the complete response to the comments in your letter of May 21, 1993, and is considered to amend and modify the April 1993 Phase I Technical Memorandum. As you stated, we will not need to republish and resubmit the Phase I Technical Memorandum. In addition to addressing specific comments, this letter proposes modifications to some elements of the Phase II work plan. The modifications consist of updating the Site Health and Safety Plan so that it addresses new Phase II tasks and reflects the current knowledge of the site; ensuring the success of the pumping test by building more flexibility into the pumping test design in the event that actual site conditions are not as expected; modifying the locations and construction of the piezometers to optimize information collection during the pumping test and to benefit from existing piezometers on Outboard Marine Corporation (OMC) property; modifying the standard operating procedure for field soil pH; correcting the parameter list for groundwater samples; and correcting the project schedule to resolve conflicts. RESPONSE TO U.S. EPA COMMENTS Comment 1: We understand this comment is related to the water level information available for wells near the OMC Plant No. 2 facility north of the WCP site. The water level data, well construction information, and boring logs shown in the Warzyn reports supplied to us by the U.S. EPA (Subsurface Mr. William Bolen June 30, 1993 Page 2 Investigation, North Ditch Area [C-9177] and Hydrogeologic Investigation (C-8342]) and the JRB report (Technical and Witnessing Case Support, Hydrogeology Study of Groundwater - Final Report, 1981) will be further reviewed and evaluated prior to drafting the Remedial Investigation Report. This information has been used to select water level monitoring points for the Phase II investigation program to select water level monitoring points. Changes made to the investigation program are detailed below under "Piezometer Location and Construction." Comment 2: This comment refers to a misstatement in the Phase I Technical Memorandum. The second sentence in the fifth paragraph of Section 2.4.2.2, Hydrogeologic Model Development, will be changed to read as follows: This pattern of flow differs from that inferred from the water table elevation contour interpretations shown on Figures 2.2-5 through 2.2-8, which indicate flow toward the southwest from the northeast corner of the site. Comment 3: The three references cited in Table 2.4-6 were chosen from the list of references in Attachment 1 because they reported naturally occurring concentration ranges for the greatest number of inorganic compounds in soils and because they summarized much of the data reported by other authors. Other references considered, but not selected, included mineral exploration guides or agricultural studies that reported concentrations for only certain elements of interest, references that reported only an average concentration instead of a range of values, references that reported values for specific geographic areas unrelated to the site, and references that were summarized in other references. We would appreciate any additional information the U.S. EPA may have on other references that should be considered. In Section 2.4.4.2, Other Compounds, the following will be added following the first sentence in the second paragraph: The concentration ranges were selected from widely recognized references which incorporate data from a number of studies and provide a relatively comprehensive list of compounds. Comment 4: In the discussion of the horizontal distribution of phenol in Section 2.4.5.1, Distribution of MGP/Coking and Creosote Compounds, the last sentence will be changed to read as follows: The source of phenol in the sample from Well MW-3D is unknown at this time and will be investigated during Phase II sampling. Comment 5: In the discussion of the horizontal distribution of arsenic in Section 2.4.5.1, Distribution of MGP/Coking and Creosote Compounds, the following sentence will be added to the end of the paragraph: The potential source of arsenic in samples from Wells MW-5D and MW-6D will be investigated during Phase II sampling. Mr. William Bolen June 30, 1993 Page 3 Comment 6: The last sentence before the semicolon in the first paragraph of Section 2.4.5.3, Identification of Phase II Analytical Parameters for Groundwater, will be changed to read as follows: The second round of Phase II groundwater samples, to be collected from all the Phase I and Phase II monitoring wells, will be analyzed for the chemical parameters listed below: ... Comment 7: The words "at the" will be deleted from the first sentence of the first paragraph in Section 2.4.6, Ecological Survey. Comment 8: The second to last sentence of the third paragraph of Section 3.3.1, Monitoring and Pumping Well Installation, will be changed to read as follows: If shallow soils in the immediate vicinity of the MW-9 well nest are contaminated with oil or tar, the MW-9 well nest will be deleted from the investigation program. The last sentence of the third paragraph of Section 3.3.1, Monitoring and Pumping Well Installation, will be deleted. Sampling of oil or dense nonaqueous-phase liquids (DNAPL) from wells is discussed in Item 10 of the IEPA comment responses presented below. Comment 9: After the first sentence in the second paragraph of Section 3.3.4, Permeability Testing, the following sentence will be added: The proposed locations for the collection of these three samples are shown on Figure 3.2-1. Comment 10: The first sentence of the fourth paragraph in Section 3.3.4, Permeability Testing, will be changed to read as follows: The water pumped from Well PW-1 during the pumping test will be pumped into a storage tank on site and stored in the tank for the entire duration of the pumping test. Comment 11: The last two sentences of the eighth bullet under Section 3.5.1, General Remediation Evaluation Parameters, will be replaced with the following sentence: TCLP samples will be placed in a stainless steel bowl, objects larger than 1/2 inch in size will be removed, and the samples will be promptly packaged in laboratory containers. Comment 12: Revised Tables 3.6-1 and 3.6-2 are in Attachment 2. The tables have been revised to include the following: risk assessment and concurrent ecological assessment duration of ten weeks; risk assessment and ecological assessment to begin after U.S. EPA approval of the Preliminary Characterization Summary; and agency review periods of 30 days for all comments or approvals. Exceedence of the schedules for U.S. EPA activities will result in equal extensions of the total project time. The critical links are illustrated on enclosed Table 3.6.2. The schedule has been corrected to resolve schedule conflicts, as described below under "Schedule." Mr. William Bolen June 30, 1993 Page 4 It is understood that PRC Environmental Management, Inc. (the U.S. EPA oversight contractor) will be conducting the ecological assessment. To assist PRC in collection of relevant ecological assessment information, a copy of the January 1992 draft Waukegan Area of Concern Remedial Action Plan (RAP) is enclosed in Attachment 3. The draft RAP summarizes the recent water quality sampling, sediment sampling, and fish flesh sampling results for the area, summarizes the major pollutants of concern for the area, and identifies uses of the area that have been impaired. Comment 13 In Table 2.4-7, the results for methylene chloride and carbon disulfide for the background soil samples were inadvertently switched. The table will be corrected to read as follows: FREQUENCY OF DETECTION (Maximum Concentration in fjg/kg) Parameter BS Methylene chloride ND Carbon disulfide 3/9 (4) This correction does not affect the text in Sections 2.4.3, Background Soil Quality Summary, and 2.4.4.4, Identification of Phase II Analytical Parameters for Soil. Comment 14: General water quality parameters will be analyzed in order to assess potential treatability alternatives. In the August 1992 Phase I Technical Memorandum, a short list of parameters (BOD/COD, oil and grease, total suspended solids) for assessing treatability alternatives was to be run on the second round of groundwater samples from all the wells. The April 1993 Phase I Technical Memorandum moved the sampling up to the first sampling event and expanded the parameter list to include sulfate, sulfide, chloride, acidity, alkalinity, total hardness, total dissolved solids, and total organic carbon. The wells for which this longer list of parameters will be analyzed were selected to be representative of the various areas around the site: MW-9S and MW-9D for the gas plant/coke plant process area; MW-7S and MW-7D for the northeast pond area; MW-12S and MW-12D for the area east of the plant process area; MW-10S and MW-10D for the area south and southwest of the process area; and MW-6S and MW-6D for the former creosote plant area.