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April 9,1990consideration and screening of remedial alternatives. Thus, we are recommendingthat a memo or letter be prepared as an interim deliverable which documentstreatability testing methods that may be considered for Tonolli. You will see thiscomment repeated in the section regarding the schedule for the RI/FS. In order tofacilitate the closer phasing of the RI and FS for Tonolli, we strongly recommendthat the bulk of field samples be collected in one initial phase of sampling. Due tothe amount of historical information available regarding sampling at Tonolli, weshould be able to select an adequate group of indicator compounds (TAL metals,semi-volatiles such as PAHs) and proceed with field sampling of a greater scopethan is proposed for "Round 1." The ability to collect more data points for eachmedia of concern in one round of field work will facilitate the closer phasing of theRI/FS, early consideration of treatability testing, and early consideration ofpotential remedial technologies. Since EPA is given an 18-month schedule for thecompletion of the RI/FS (see additional comments on Section 4),the close phasingof these activities is of utmost importance. We would like you to consider revisingthe phased approach to the field sampling work along the following lines: Collectfield data from approximate sampling points described for Rounds 1 and 2 in oneevent; collect majority of samples (distinct number permedia) for limited analysis(i.e., 75% for indicator compounds), and collect limited number of samples permedia ( i.e., 25%) for full TCL/TAL analysis. This approach would involveconstructing all site monitor wells at one time, thus only one mobilization effortwould be needed. Also, having a larger volume of site data at once will facilitate theprocess of defining site "background" conditions, scoping any additional datarequirements (i.e., off-site sampling), reviewing treatability testing methods,remedial technologies, and ARARs. Please note that this is not engraved in stone,and that we would like to discuss this major revision, as well as other options withyou as soon as possible. There are other approaches that we could also consider tomeet this same objective of collecting a large number of data points at one time.For instance, a greater use of the field screening method (XRF) for onsite soilsinvestigation could also be considered to accomplish this time-saving goal. You willalso note comments on latter portions of the work plan that may assist you inconsidering this revised sampling approach.This entire section has been revised to reflect EPA's comments Procurement of access and subcontractors is included in the scheduleand budget for each individual task. The PRPs would like to review the fact sheets and other items for publicdistribution before they are distributed. More activities have been included during Round 1. All wells will beinstalled. The geophysics has been expanded to include inverseMAC/SY071/00013jfR30QQ5i

April 9,1990modeling of EM34-3 conductivity data, EM39 borehole conductivitylogs, seismic reflection profiling, and a metal detector survey. Thetemperature logs have been removed on the basis of input from EPA. Task 5, Treatability Studies, will be initiated much earlier in the RI,due to the large amount of data already collected. Prior to treatabilitytesting, a scoping meeting will be held between EPA and the Tonolli SiteSteering Committee representatives to discuss remedial alternatives.Following the scoping meeting, a memo or letter will be prepared tosummarize the conclusions of this meeting and discuss the scope ofTreatability Studies.All types of sampling activities, with the exception of biota, will be conductedduring Round 1. Round 2 will include second sets of groundwater samples,leachate samples, and surface water and sediment samples. Round 2 willalso include biota sampling, as outlined in the revised work plan, if results ofRound 1 sampling and the environmental assessment show a biotaassessment to be necessary to evaluate the environmental impact of the site.As discussed in the March 21, 1990 meeting, 10 to 15% of the samplescollected during Round 1 will be analyzed for TAL/TCL parameters. Theremainder will be analyzed for the following indicator parameters: arsenic,cadmium, copper, lead, selenium, zinc, mercuiy, and polynuclear aromatichydrocarbons (PAHs).15. Page 3-4 - beginning with Section 3.4.1 - up through the description of eachtask (3.4.4) -The description of work to be completed under each distinct task lacksinformation regarding the objectives of doing the work. It is important for all thework plan readers to be aware of what will be done v/ith the results collected fromeach task. Without a clear description of the objectives for individual tasks, it isdifficult to evaluate the need for the proposed work, and how it will assist thedecision maker during the RI/FS process. The need for this information may bebest reflected in the comments that immediately follow this.The tasks and task descriptions have been revised. Objectives for each taskare explicitly stated.16. Page 3-4, Section 3.4.1 - Also refers to page A. 1-5 (SAP) - Surface geophysics- What type of calibration is needed for these instruments to be able to differentiatebetween "background" (coal refuse) and any site-related contamination? Wouldn'tyou expect a great deal of interference from the metals present in the coal refuse?With the knowledge that coal refuse and alluvium lie beneath the site (up to 100feet), what type of stratigraphy information would you expect to be collected? Towhat depth are these methods effective - keeping in mind any possible interferenceMAC/SY071/000136RR300052

April 9, 1990by the coal refuse? How will the stratigraphic information be used? Will you beable to detect a clearly defined plume? Does this provide quantitative information?What is the objective of using surface geophysics within the limits of the landfill andformer lagoon areas? Do you have information that leads you to suspect thatcontamination or othermetal materials exist outside of the bounds of these disposalunits? How will this information be used? Will additional investigation approachesbe used to support the surface geophysics findings?17. Page 3-9, 1st full para. - Borehole geophysics - Unless you complete loggingin bedrock, what type of stratigraphic information do you expect to gather, and howdo you propose to use this? Do you expect to identify discrete flow zones within thealluvium? Other than describing the site's subsurface stratigraphy, what will be donewith this information? Will this be used to define GW flow and migration pathwaycharacterization?Response to Comments 16 and 17:Additional geophysical methods have been included to aid in determining sitestratigraphy and its influence on conductivity.Seismic reflection profiling is proposed as an additional technique todetermine stratigraphy over wide areas of the site, particularly where theelectrical conductivity (EM34-3) and resistivity (ER) methods are to be used.From seismic and borehole geology and geophysics logs, the site-widestratigraphy can be inferred, including thicknesses of coal refuse.Borehole conductivity (EM-39) in two new PVC-cased wells (which will becontinuously split-spooned) will provide a correlation of conductivity tostratigraphy. These wells are MW-10D and MW-18D which are upgradient ofthe direction in which groundwater from the Tonolli Site has most likelymigrated. One well (MW-18D) will be located in an area which has asignificant thickness of coal refuse and one well (MW-10D) where the refuseis thin or not present. The information from borehole geophysics will be usedto assess conductivity associated with geologic strata (including fill). Thesurface electrical methods, EM34-3 and ER soundings, will be used in thevicinity of the wells to ascertain the influence of varying depths of differentgeological materials on the readings obtained with each instrument. Thisprocedure will be carried out in the vicinity of other gamma-loggedmonitoring wells. The EM34-3 will also be used around the perimeters of thesite, the landfill, and the lagoon, as described in the revised work plan, todelineate zones of high conductivity. The EM34-3 survey will measureconductivity at six cumulative depths at each station location. Site perimetersurveys on the north, east, and west of the site will be run along five linesMAC/SY071/000137&R3G0053

April 9,1990spaced 50 feet apart (from 0 to 200 feet from the perimeter) for eachdirection. Readings will be taken at 50-foot intervals. Along the south, linesand measurement locations will be spaced at 25-foot intervals from thesouthern perimeter to Nesquehoning Creek.High conductivity measurements will be confirmed with electrical resistivitysoundings. Correlation of ER soundings to geology will be provided byinterpretations seismic reflection profiles through the area and comparisonof ER soundings to split spoon logs, natural gamma logs and EM39conductivity logs at new and currently existing wells, as noted above.Information generated is quantitative relative to site conditions. Differentgeologic materials do have characteristic ranges of seismic velocities,conductivity, resistivity, and natural gamma emission; however, many factorsinfluence geophysical data, hence, several techniques are being used toevaluate site conditions.No discrete flow zones are expected to be measured within the alluvium.Seismic reflection may be able to determine waiter table depth, and the depthof any horizontally extensive clay or silt zones, vwth a thickness greater than 3to 6 feet, within the alluvium. All the geophysical information will be used tocharacterize contaminant migration pathways amd groundwater flow.18. Page 3-9,2nd full para. - Soil sampling - As stated previously, we would like tocollect more data points in one round of sampling. In discussing a revision to thesampling approach, we may also re-visit the proposed soil sampling, or at aminimum, your objectives for the proposed scope of soil/waste materials sampling.In order to characterize the extent of contamination in this media, it will be veryimportant to define a site" specific background level for indicator compounds. DoesMW-10 reflect background for Tonolli? Is coal refuse material present at thislocation also? After defining background, how do you plan to separate out thisbackground from site-related contamination?Once again, it would be helpful to have a complete description of the objectivesfor the proposed scope of soil/waste material sampling. For instance, what is theobjective for sampling coal refuse? Since we have little to no native soil at the site,this could be quite a problem, particularly with defining background conditions.Will special analysis be required to accomplish the assumed goal of delineatingareas of contamination within the coal refuse (a.k.a. soils)? Will the chemical andphysical characteristics of the coal refuse alter our evaluation of the fate andtransport mechanism How will the field measurements and tools be used to pinpointsampling locations? Will the field data generated by the XRF be made available toEPA? The 13 waste samples proposed should be defined. What types of wastes(and locations) will be sampled, and for what reason? While sampling in areas ofMAC/SY071/00013&R300Q5U

April 9,1990concern is appropriate, we must also determine the nature and extent ofcontamination across the entire site. At this time, the proposed soil samplingappears to be biased toward the eastern portion of the site. Do to the proximity ofresidents along the western boundary of the site, it is appropriate to offer additionaldata points that will allow us to characterize the entire site. Also, based onhistorical air monitoring information, it is apparent that Tonolli's operationgenerated lead in paniculate form. This offers further impetus to sampling areasnear potential human receptors. This data maybe needed during the riskassessment. We recommend that an inventory of onsite structures be completed,and that this be documented and delivered to EPA for consideration of samplingduring the RI/FS. It will be quite difficult to evaluate remedial alternatives withoutdata regarding the conditions of onsite structure.The work plan has been revised to reflect these comments.19. Page 3-9, 3rd full para. - Sampling of onsite structures - We recommend thatan inventory of onsite structures be completed, and that this be documented anddelivered to EPA for consideration of sampling during the RI/FS. It will be quitedifficult to evaluate remedial alternatives without data regarding the conditions ofonsite structure.This sampling and assessment of on-site situations is now included in thework plan.20. Page 3-9,3rd full para. - Subsurface soil samples Please clarify the type of soilsamples to be collected. At this point and later in the document, the types ofsubsurface soil sampling,and associated methods for collection become confusing.For instance, the soil samples discussed in this paragraph what method/device willbe used to collect them? If you are to screen the samples at two foot intervals, what"is the objective? The samples are already designated to be collected from 0 to 1 footbelow surface, and one at a lower depth interval. On what basis will the sample tobe collected at a lower depth interval be selected? What if the XRF does notdistinguish between the different depths for lead content?This has been clarified in the work plan.21. Page 3-5, Figure 3.2 - There is an unlabeled proposed soil sample near thelagoon. Please label/describe. Bear Creek should be included on this figure andfigure 3.3. Specify the types of waste samples to be collected - i.e., what is W-3 - acoal/culm bank sample? Is this a background sample? Figures should include alllocations for proposed air monitoring.These items have been addressed in the work plan.MAC/SY071/000139&R300055

April 9,199022. Page 3-7, Table 3.1 - GW samples - Analysis must be include for both filteredand unfiltered fractions. Appendix A (SAP) describes the collection of both, butTable 3.1 does not. See comments/attachment from EPA's Bioassessment Groupregarding the recommended parameters for analysis to evaluate impacts to flora andfauna. These parameters should be reflected here. Also, the Bioassessment grouprequires both filtered and unfiltered fractions for surface water samples on metalssites. GW samples - The proposed number of samples for Round 1 does not includesampling of Panther Creek's wells as stated in Section 3.4.The work plan has been revised to reflect these comments.23. Page 3-13, Section 3.4.2 -2nd para. - XRF use to screen soils at five-footintervals, two samples to be selected on this basis for analysis - What if there is noreading on the XRF to assist with this decision? On what basis will the samples becollected? What will triaxial permeability analysis tell us? What are the objectivesfor this? 4th para. -What are the objectives of the slug test? Will this information beused to evaluate the possible interconnection between the shallow and deepaquifers? 5th para. - If you are to use the Panther Creek wells, will you account forthe difference in well construction, screen length, etc. when reporting the datacollected? Since these wells have a long screen length, the water levels will beaverage across several water-bearing zones. We recommend that if these wells areto be used, that caution if used in reporting and using the data.This work plan has been revised to clarify these items.Objectives and method for slug test analysis have been clarified.Panther Creek well data will be used for comparison with new on-sitemonitoring wells, but reporting of data will clearly state the differences inwell construction and the influence that these construction differences haveon the data.24. General comments for Section 3.4.2 - During a site visit in December 1989,two wells were found in the southwest corner of the site. Information should becollected on the construction of these wells, and consideration given to using themto monitor this portion of the site. Once again, the GW section would benefit from amore comprehensive description of the objectives for the work proposed. Forinstance, will a plume diagram be generated, modelling be completed, or what willthe output be from the GW investigation and testing? It is also important to offer, ata minimum, some consideration to the residential arid/or municipal wells in closeproximity to the site. Information should be collected to define the location of anyresidents adjacent to the site who may be onprivate wells, and information regardingthe depth and construction of the wells should be gathered, perhaps via a wellfiR300056

April 9,1990survey. We should also have an account of the locations of municipal water supplywells in the site area.These newly-discovered wells will be inspected to the extent possible duringthe field investigation; however, ES does not recommend sampling wells forwhich no record of installation and construction exists.Groundwater flow modeling may be performed if necessary to assess effects ofpotential remedial measures on groundwater flow characteristics.Contaminant transport will not be modeled because the wide range ofvariables and assumptions make this type of modeling not useful. Thegeologic, hydrogeologic, geophysical, meteorological, and analytical data willbe used to assess contaminant transport.The source of drinking water for local residents will be assessed during theremedial investigation. The municipal water supply wells in the vicinity ofthe site are shown on Figure 2.L The wells for the other water system in thearea, the Summit Hill Water Authority, are topographically isolated from theTonolli site and over two miles away in an adjacent drainage area.25. Page 3-14, Section 3.4.3 - As stated previously, rather that complete thissampling in rounds, it would be more effective to collect all the data points at once.We recommend that a sampling point be added immediately down-stream of theBear Creek inflow to characterize any contribution from this stream. Also, due tothe in-field observation of a pipe leading from the site area into Bear Creek, furtherconsideration should be given to adding sampling points along Bear Creek.These comments have been incorporated into the work plan.26. Page 3-14, Section 3.4.3 - 2nd para. - Manhole sample (L-2) -Do you proposeto use any special sampling equipment or procedures to collect this sample? Healthand safety considerations should be reviewed for this activity. Will any sc

RESPONSES TO U.S. EPA COMMENTS DATED FEBRUARY 28,1990 (Comments appear in regular type; responses are in bold type) Enclosed for your review and consideration are EPA's comments on the RI/FS Work Plan submitted by Engineering Science and the PRP Steering Committee for the Tonolli site. The