ftR500079 · 90% maximum Standard Proctor density. AGI considers it unacceptable to approve of the cap material density based on approximations or overall averages. For the cap to

AMERICAN GEQTECH, INC.fieottthnlcal, Rydrogtolbglcat, Environmental, Structural and Kattrlal Ttttlng1801 rcm Avt, V/cwUiIno Illlt. PA 19609 /T«l. 610 670-9055/Fwts «10 678-Z719SOS Main StrMt. Uoodbrfdb*, «.J. 07095 /T«t. 908 750-1668

Mr. Anthony KollerRemedial Project Manager •EPA, Region XII ; US EPA841 Chestnut Building * Etatern PA RemedialPhiladelphia, PA 19107 Mays, 19 9 5 Section SHW2J8

SUBJECT: EPA SUPERFUND SITE 03-HW-21BERKS LANDFILLREVIEW COMMENTS ON EPA'S RESPONSE ON MAY 1,1995

Reft EPA Response to Chung's Letters (3/11/94, 6/21/94, t3/24/95) dated May 1, 1995

Dear Mr. Kollert •

On behalf of the Concerned Citizens of Western Berks County, I have reviewed your response datedMay 1, 1995 and feel that the letter addresses our concerns on the following issues. However, some ofthe issues raised are not yet folly answered:

1. The Diabase as a Hydraulic Barrier - AGI has concern about the extent and integrity of thediabase as a barrier to contain the contaminants from the landfill. The EPA has dismissed theissue, accepting Qolder's interpretation of the geology. They claim that no data conflicts withthe interpretation that, throughout the site, within a depth of no more man 200 feet, the perme-ability decreases to form a significant barrier. The EPA also accepts the "diabase bowl* inter-pretation, mat around or near the borders of the landfill, the diabase extends to the surface, toform a complete barrier. AOI feels, since few borings were located around the boundary of thebowl and there is no support for that interpretation of the geology, that the analysis is stillquestionable. The "diabase bowl" theory of containing the contaminants within the landfill areamay not be true as explained in the following: •

. In Geologic Cross Section B-B', Figure 3-1 1 (Figures 1 & 2), it indicates that there is a total of210 ft (700* -490') elevation drop from south boundary of the Eastern Landfill to its northboundary. There is a 30 ft elevation drop from the north boundary to the bottom of the Cacoos-ing Creek (El. 460') within 60 ft distance. High permeable rock such as sandstone and lime-stone exists directly beneath the Landfills. A layer of overburden soils with approximateaverage thickness of 20' (20* in G-4 and 21.5' in G-3) was found during well drilling. Theoverburden soils consists of silty clay, silt, and sand. The upper layer of the diabase isweathered and fractured with the permeability value of IxlO*4 cm/sec. According to the drill-hole logs from Appendix B-l of the Draft Remedial Investigation Report, the low permeability(10 •* cm/sec) of diabase hi Holes G4 and G5 could not be achieved until drilling to depths of atleast 185 and 110 feet, respectively.

With the artesian condition found during drilling in G-4 and near the low area in the northwest- -"era landfill, the contaminant transport route may be more vulnerable to follow the overburdensoils and surface fractured rocks to the northwest corner of the site into the creek.

• - ' " ' ' " • ' ' . • . " - • . • • • , ' ; : » *2. The Landfill Cap Integrity - the EPA states that the cap material is, on average, compacted to

approximately 90% of maximum Standard Proctor density for the eastern landfill. The EPA' also claims that the average density for the western landfill cap material is within the range of

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85% to 92%, according to data presented by Colder. However, as mentioned in AGI's June21, 1994 letter, out of 8 Held tests, ranging from 73.6% to 100.9%, 5 of the tests were below90% maximum Standard Proctor density. AGI considers it unacceptable to approve of the capmaterial density based on approximations or overall averages. For the cap to be effective, theweakest point of the cap must be well compacted, with a low permeability. Remediationmeasures must take into account that the cap will only be as effective as its weakest point.

Also, AGI mentions the variation in cap thickness from 36" to less than 2". with more than60% of both landfill areas having thickness less than the specification requirement of 24*. TheEPA mentions the revision of the RI Report, which reads: "More than half of the Site is cov-ered with cap materials exceeding 12 inches in thickness although there remain large areas thathave limited cap thickness. The* placement of additional cap material and a regrading programmay be necessary to increase the thickness of the cap in these areas." The first statement ofthis revision may be a correct assessment of the condition of cap material, however the follow-ing statement regarding remediation is inadequate with respect to the specification require-ments. Remediation measures must be taken to repair any areas that are less than 24* thick-ness.

Modeling of the transportation of contaminants on site and in groundwater flow must also takeinto consideration specific weak points of the cap material. Overall averages for the cap densi-ty and permeability may leave many realistic possibilities undiscovered. Using specific valuesfrom testing of samples in various regions will give modeling a better approximation of the siteconditions. . .

3. The EPA mentions the interpretation of evidence of groundwater contaminants. They claimthat the residential wells have been proven to be sufficient for monitoring groundwater in thatarea. It is also stated that, "The option to install additional monitoring wells along the tributarywest of the site will be evaluated as part of the Feasibility study." AGI feels that additionalmonitoring wells are needed, especially since there Is doubt about the completeness of theevidence for much of Gotder's interpretations. If there are assumptions which have been made,*as has been implied, with no data to. confirm or disprove them, then more data should begathered before a conclusion is accepted.

Another issue made by AGI regarding well monitoring, which needs further consideration, isthe replacement of monitoring wells. In the RI/FS Work Plan from May 1992 (page 75-6), itwas stated that "The bydrogeologic investigation will include decommissioning and retrofittingexisting wells, drill-stem testing of the stratigraphie holes and packer testing.... Additionalupgradient and downgradient monitoring wells will be installed, followed by a second round ofenvironmental sampling.,* In the March 11, 1994 letter from AGI, Comment 6 mentioned highcontent of Vinyl Chloride and Trans-l,2-dichloroethene, from some wells hi a 1986 sampling.Well MP-18D was decommissioned in October 1992 and replaced by GR-18D. The two closestreplacement wells, GR-18D and GR-19D are each more than 100 feet from the original wells;and therefore, are inadequate for sampling for the contaminants that were detected at well MP-18S/D. Because of the complex geology on site, and the possibility for localized changes ingroundwater flow direction, replacements assumed to be downgradient at 100 feet from theoriginal well may not be In the flow path of groundwater from the well. The replacement wellsmay be sampling from a different localized aquifer. AGI believes it may be necessary t<* install

/ additional monitoring wells. All monitoring wells should be tested more frequently (only twosets of results are available for on-site wells since 1992, and only four sets of results are avail-able for evaluation of the residential wells). Monitoring well samples should also be tested for

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chemicals detected by NUS/EPA since 1985, to confirm whether or not any of these contami-nants are still present at any location on site.

4. AGI mentioned in the March 11, 1994 letter, that site history and employee interviews hadrevealed information about the existence and suspected condition of alkali sludge disposal. TheMarch 24, 1995 letter, reviewing EPA's comment 15, points out discrepancies in the informa-tion from employee interviews, about the existence of drums of waste. Since mis issue was notsettled in the May 1, 1995 response, AGI asks mat these issues are investigated further, andmat the results are made clear to all parties.

5. AGI disagrees with the statement mat the "EPA is not aware of any modern sinkhole activity atthe site." It had been mentioned by Walter Wink, one of the previous landfill workers duringthe 6/25192 site interview by Dianne Walker, EPA's Former Project Manager and Randy Whiteof Colder. Walter Wink explained that sinkhole development had occurred during construc-tion. If this sinkhole activity was affecting the site surface at the time of landfill construction,then it is likely that the shallow subsurface has some current sinkhole activity.

6. Finally, AGI finds that Berks Landfill is located within 3 miles from the January 15, 1994Earthquake. Future earthquake(s) might change the fracturing characteristics of the rock underthe landfill and the liner integrity. Colder has not responsed the "Earthquake Issue" whichmight affect the remediation method selection. A copy of my seminar/research material on mistopic is enclosed for your review and use.

Under the Freedom of Information Act, American Geotech requests a copy of the revisions to Draft RIreport, which were submitted to USEPA by Colder on March 13,1995. We also would like to obtain acopy of the outstanding comments on BRA issues discussed during the March 15, 1995 meeting bet-ween EPA and Colder and a copy of Golder's backup information on March 16, 1995 submitted toEPA. We would also remind you mat we have still not received Golder's February 1995 ProgressReport and are awaiting a copy. If you should have any questions, please feel free to contact me at(610)670-9055.

Kin Y C Chung, Ph.D.,P.E.Consultant for CCWBC

End.

CC: Ms. Vivian FaustRon KHmkowsld (PADER)

Cross Roads Center1005 Cross Roads BlvdReading 19605

John Ravert, County EnvironmentalistBerks County AG CenterLeesport, PA 19533

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EARTHQUAKES IN BERKS COUNTYPRESENTED AT OCTOBER READING AREA PROFESSIONALSGROUP (PSPE, ASCE, & PSLS) JOINT DINNER MEETING

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BYKIN Y C CHUNG, Ph.D., P.E.AMERICAN GEOTECH, INC.

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