RESPONSE TO COMMENTS FOR
THE ILLINOIS CENTRAL SPRING SITE
BLOOMINGTON, INDIANA

July 8, 1999

This document responds to arguments, assertions, and concerns received by the United States Environmental Protection Agency (U.S. EPA) from CBS Corporation (CBS). These comments were originally submitted to the U. S. District Court for the Southern District of Indiana in the form of a "status report," filed with the Court on or about July 8, 1999. CBS provided U.S. EPA with a copy of this status report. The status report was prepared and filed with the Court after U.S. EPA issued its June 22, 1999, Action Memorandum for the Illinois Central Spring removal action site. The June 22, 1999, Action Memorandum served to modify the scope of the removal action as originally described in the first Action memorandum for the site issued on September 28. 1998. The June 22, 1999, Action Memorandum also authorized a ceiling increase to reflect increased costs in the removal action resulting from the changed scope of the removal action.

The majority of CBS's comments consist of criticism of major design components and other design related issues, and reflect CBS's disagreement with U.S. EPA's overall response approach. The differences between the U.S. EPA and CBS were previously highlighted in CBS's May 12, 1999 correspondence to U.S. EPA, and U.S. EPA's response dated June 21, 1999. Indeed, in the July 8, 1999, status report CBS for the most part repeats concerns and makes arguments that CBS brought to U.S. EPA after the issuance of the initial September 28, 1998, Action Memorandum. Accordingly, U. S. EPA was aware of CBS's concerns and arguments when the June 22, 1999, Action Memorandum was issued. At that time, however, U. S. EPA did not prepare a formal response to comments, because U. S. EPA is not required to. To ensure a clear record in this matter, U.S. EPA has determined that it is appropriate to prepare this memorandum responding to specific concerns of CBS.

COMMENT: CBS expresses a general concern regarding the increase in costs between the original Action Memorandum dated September 28, 1998, and the Action Memorandum dated June 22, 1999. CBS's comment regarding concern over the increased costs is closely tied to its comments regarding what it perceives to be an enlarged scope of the removal action. According to CBS, the changed scope is demonstrated by, for example, U.S. EPA's determination to design the plant in a manner to ensure that it is capable of addressing storm water flows from a 25-year storm event.

RESPONSE: The June 22, 1999, Action Memorandum listed reasons why the project, and hence the cost, differed from the September 28, 1998, Action Memorandum. These items are again listed and a more detailed explanation is presented as to why the design changes were deemed necessary, and how they affected the project costs. .. . . As an initial matter, in considering the differences in both the scope of the project and the costs between the remedial contractor (Tetra Tech) and the removal contractor (Earth Tech), it must be noted that the primary purpose of the remedial contractor (who assisted U. S. EPA in developing the conceptual outline of this removal action) was not to provide an engineers estimate of the cost of the project, but was simply to compare the cost of the various removal action options being considered and to assist in identifying a cost effective alternative. Once the project was assigned to Earth Tech, the removal contractor, the engineering and design was initiated. This work took a full four months at a cost of $413,000 to produce an engineers estimate and to date is the only true estimate of the projects costs.

The conceptual system and the system as designed are consistent in approach - both call for a plan capable of treating up to 1,000 g.p.m, and both call for storage of additional flow. The Illinois Central Spring water treatment plant is intended to address PCB releases from the Spring during storm events when the water is at its highest flows. The logic for designing and constructing a plant capable of addressing high flow storm water events is that it is during those events that high PCB-mass concentrations are released from the Lemon Lane system and found in the water emerging at the Spring. This is in contrast to the substantially lower PCB-mass concentrations found during the more-typical low flow periods. In the system as designed, however, storage capability has been revised from two-acre feet to four-acre feet. Further, during the course of the design process issues came into focus that had not been previously considered during the conceptual phase, but that none-the-less needed to be addressed. Other issues that were generally considered during the conceptual phase came into sharp focus requiring, in some instances, a re- evaluation of (and in some instances changes to) the conceptual approach.

Thus, the flexible design as approved by U.S. EPA has combined the initial guidelines of 1,000 g.p.m. of water treatment using basic water treatment technology and a storage of 2 acre feet, with the addition of more storage capacity. Outside of adding the 2 acre feet of storage, the U. S. EPA has adhered to the initial guidelines. U. S. EPA has determined that by designing the Illinois Central Spring (ICS) plant to address a 25 year storm event by simply adding 2 acre-feet of storage capacity and additional assorted pumps and miscellaneous equipment, is protective of Clear Creek. In the 1998 action memorandum, U. S. EPA did determine that a two-acre feet storage system would be sufficient for storm water flows. However, U. S. EPA in part founded its decision in this regard based on data regarding one isolated year of storm data. Earth Tech reviewed charts and data from CBS, and considered generally accepted design criteria described in engineering manuals, and determined that it is more appropriate to design a system capable of addressing storm water flows during a 25-year storm event. A 25-year storm event is a common event to design to and has been used by other government agencies. The treatment plant and associated storage capacity are part of a flexible, interim design. Final decisions regarding water treatment needs at the Spring will be made as part of the Lemon Lane remedial action. Based on additional data that may develop in coming years, EPA will make determinations r~o~rAino discharge limits, and any additional treatment and storage requirements.

CBS raises as a specific example U.S. EPA's decision to amend its removal action to allow for design and construction of a system capable of addressing storm water flows from a 25-year storm event (defined as a 3.7" rain in a 6 hour period by the National Engineering Handbook). This differed from the conceptual approach of a plant capable of treating contaminated water at a rate of 1,000 8pm and with the ability to store up to two acre-feet of water pending treatment. As an initial matter, the risks posed by the Illinois Central Spring discharge include the discharge of PCBs from the Spring. The amount of PCBs on a mass basis found in the discharged ICS storm water increases during large storm events. The PCBs are discharged as part of the suspended solids, or sediment, coming out ofthe spring during high-flow events. U.S. EPA's decision to design the plant to handle the total gallons per minute of a 25-year storm event, together with a removal efficiency of 1 micron of contaminated sediment, was driven, in part, by the fact that for this relatively small investment of approximately $350,000 for additional storage capacity, an added degree of protection for Clear Creek can be achieved, which will reduce PCB concentrations to a range of 0.1 to 0.3 ppb (parts per billion) of PCBs. As part of the interim design, however, U. S. EPA, based on a consensus of opinions by Earth Tech's design team, agreed with the recommendation that it was appropriate to design the treatment plant to address a 25-year storm event. It was understood that the added costs associated with the addition of an extra two acre-feet of storage would be in the range of $350,000 (including adding extra pumps). by employing four acre feet of storage, the treatment plan is capable of capturing and treating 70 percent of a 25-year storm event's water flow, as opposed to only 48 percent of the same storm event using two acre-feet of storage. Thus, for a relatively small incremental cost increase when considering the overall project and cost, a significant additional measure of protectiveness is achieved.

EPA did not prepare a "particle size study" as part of its design of the interim treatment system. This was due, largely, because of time constraints, driven by a Court Order that requires the start of the clean-up of the Lemon Lane Superfund Site (which is hydraulically connected to the spring and the source of the PCBs emerging from the spring) by the spring of the year 2000. To enable the Project to be more cost effective and in lieu of a particle size study, U. S. EPA instructed Earth Tech to design the plant to be capable of removing storm water total sediment down to a particle size of 1 micron. Below 1 micron, any suspended sediment is considered colloidal and to remove a colloid from the spring water would involve flocculation and coagulation and this technology would be considered "ultra filtration." It was roughly estimated that to add a flocculation and coagulation system to the treatment train would add an additional $1,000,000 to the project costs. Absent specific the information regarding particle size, there was insufficient information on which to base a design for a plant capable of adequately addressing site risks using as a general design parameter the ability to treat 1,000 g.p.m. of storm water and capable of 2 acre-feet of storage. U.S. EPA could have employed chemical floculation or ultra-filtration to capture particles smaller than 1 micron without performing any additional study, but EPA elected to defer a decision regarding how to address particles smaller than 1 micron until after completion of a treatability study. EPA's decision to wait for the results of a treatability study will help ensure that the treatment approach used in the design of the final treatment system is best suited, and most cost-effective, for addressing particles smaller than 1 micron. Addressing colloids and the use of ultra-filtration will be considered in the final remedy selection process.

U.S. EPA's decision to design the plant to address the risks from storm water flows during a 25- year storm event (as opposed to the conceptual 1,000 g.p.m with 2 acre feet of storage approach) results in the plant's ability to increase its PCB percentage recovery from an estimated 40% ofthe PCB mass released during such an event to 70% of the PCB mass released during a 25-year storm event. This level of"protectiveness" to Clear Creek was deemed appropriate and necessary by the U. S. EPA. In response to CBS's claim that the 25 year storm event is not appropriate to design to, it should be noted that Earth Tech's Project Manager recommended that a 25 year storm event is a common event to design to and in his experience, has been used by other government agencies, and is consistent with design parameters described in generally accepted engineering manuals.

COMMENT: CBS expresses concern over U.S. EPA's decision to switch from the conceptual plan contemplated in the September 28, 1998, Action Memorandum to design and construct an open lagoon capable of storing up to 2 acre-feet of storm water flow, to instead using two above- ground storage tanks capable of storing up to 4 acre feet of water.

RESPONSE: During the conceptual phase in the Tetra Tech report, a lagoon capable of two acre- feet of storage water storage was to be located in line within the bed of Clear Creek. This "basin" would be used for both storage of storm water pending treatment, as well the settling of the suspended solids. During the design phase of the plant, U. S. EPA determined that the use of a lagoon in the type situation presented at Illinois Central Spring would not perform either the storage or the settling features very well, and that significant risks would be posed if a lagoon were relied on based on the topography of the area.

During the design phase, U. S. EPA abandoned the lagoon concept primarily because of the instability of the Karst topography present throughout boundaries of the site. Because of the Karst topography, and the various cracks, vugs and "swallow holes," at the Site, U. S. EPA determined that significant risks of release of contaminated materials was presented by reliance on a synthetic liner system placed on this type of subsurface. Ensuring liner integrity was determined to be too problematic to warrant proceeding. Among the other problems identified with the use of a lagoon system are the following: A limited ability to remove from the lagoon sediment and foreign material such as leaves, twigs and other debris without risking the integrity of the liner; extended periods of time where there lagoon could not be used (unless the lagoon is compartmentalized) during maintenance work or during sediment removal, thus placing the stream at risk; concern over attractive nuisance issues; concern over wildlife exposure to contaminated sediment accumulated in the lagoon; and, finally, concern over the ability to detect for rips or tears in the liner of the lagoon, an item that a double walled bottom of a storage tank would eliminate. Abandonment of the lagoon concept (and instead using a storage tank system) also resolved problems associated with housing, mounting, and protecting the pumps and assorted electrical components needed to transport the contaminated water to the treatment plant. By constructing a spring water receiving sump and an accompanying small building, this important function now falls into place.

Although CBS is critical of U. S. EPA's decision to abandon the lagoon concept in favor of a sounder above-ground storage tank system, CBS has not presented U.S. EPA with any geophysical work of its own regarding the site that contradicts U. S. EPA's work.

COMMENT: CBS is critical of U.S. EPA's decision, in the 1999 Action Memorandum, to address handling of solids and sediments. In particular, CBS is critical of U.S. EPA's decision to provide for a filter press in the interim system.

RESPONSE: EPA's decision to address solids in the design ofthe interim treatment plant (which is scheduled to be operational in March of 2000) recognizes the potential for large amounts of sediment to be released from Lemon Lane during the Lemon Lane remediation, scheduled to begin in the spring of 2000. Thus, as part of the design of the interim treatment system, U. S. EPA determined that there was a need to handle sediments collected during the capture and treatment process. Earth Tech completed a flow diagram showing how the sediment will be managed by the plant once captured. By use of a thickener and a filter press, the PCB laden sediment can be dewatered and shipped off site for disposal. U.S. EPA's use of a filter press, and providing a means for dealing with sediments that will result from treatment does not make this system any less of an interim system. Rather, it provides for the ability to address the anticipated risks and types of materials that need to be addressed as part of the treatment process in a cost-effective manner. De-watering the collected sludge and sediment prior to off-site disposal is cost-effective, because the resulting "dry" material weighs less and, therefore, costs less to transport. De- watering the materials also reduces risk, because the risk of releases during transport through liquid leakage are significantly reduced.

COMMENT: CBS is critical of U.S. EPA's decision making regarding the treatment system treatment capacity, which is a matter of storm water management. CBS continues to advocate the use of its proposed "interim system" of carbon filled bags placed in the stream bed.

RESPONSE: The Illinois Central Spring water treatment plant is intended to address PCB releases from the Spring during storm events when the water is at its highest flows. The logic for designing and constructing explant capable of addressing high flow storm water events is that it is during those events that high PCB-mass concentrations are released from the Lemon Lane system and found in the water emerging at the Spring. This is in contrast to the substantially lower PCB- mass concentrations found during the more-typical low flow periods. Designing a plant to treat spring water only during low-flow periods would, however, allow releases of extraordinarily large amounts of PCBs to be released into the environment during high-flow storm events. More than only low flows need to be addressed to protect Clear Creek and neither the carbon filled bag approach, nor a portable system could handle high flows. The carbon bag approach would be overwhelmed during a storm event, and likely washed out of place in a high-flow environment. Sedimentation is also likely to prevent the carbon bag approach from being effective even in the short term. A portable plant of the kind CBS suggested in its June 1, 1999, proposal, cannot adequately protect Clear Creek. A portable system might remove PCBs coming from the spring curing low slow, out low flow is not the concern. Rather the concern is addressing the release of PCBs that occurs during storm events. The approaches of CBS do not adeouatelv addressstorm flows, and fail to adequately address the matter of storage of water pending treatment. The turbidity of the spring water increases as the severity of storm events increase, thus increasing PCB concentrations during high flow. This is the period where the operation of the plant is most critical from the standpoint of protecting Clear Creek. U. S. EPA's "flexible design" plant will handle high flow where a portable plant cannot.

To maximize the amount of PCB sediment laden water that can be treated during a storm event, U.S. EPA decided to partition off the surface runoff from the spring runoff et the site of the spring emergence. Since the spring is located in a valley, this can be simply done by constructing a storm water separation wall which will greatly reduce the amount of clean surface runoff that otherwise would be mixing with the contaminated runoff during a storm event. The clean surface water will be routed untreated to Clear Creek at a location down stream from the plant, via a 24" bypass, while the water containing the PCB sediment will proceed to the plant via its own 24" pipeline. Accordingly, U. S. EPA has considered the matter of capacity and has taken those steps that are cost effective to reduce the total volume of water that needs to be treated.

COMMENT: CBS is critical of U.S. EPA's decision to construct a building to house equipment and machinery associated with the interim system. CBS is also critical of EPA's decision to size both the building, and the piping associated with the treatment system, in a way that they can be used in and expanded system without modification or additional cost.

RESPONSE: A building is necessary to house the PCB treatment process equipment to protect the equipment from the elements and to ensure the systems ability to operate. CBS's suggestion that no building at all is necessary therefore makes no sense. Regarding cost, at the conceptual stage, building costs were estimated at $45,000. Using a low hypothetical cost of $50 per sq. ft., the space afforded at the conceptual stage would be in a 30'x 30' building. This size building would be far too small even for the treatment process that was being considered at the conceptual stage. U.S. EPA's building, as designed will cost approximately $400,000 range, but will be able to house the added thickener and filter press along with space to house on office, and a small laboratory with lavatory.

The building also contains 40% added space above and beyond what will be used by the Earth Tech process. This added floor space is projected to be used in the "final remedy" phase perhaps to house the "ultra filtration" equipment and is part of the "flexible remedy" that U. S. EPA has designed for in its project. The cost of the building "as built" is approximately $2,048,500. The cost ofthe additional 40% space is approximately $281,700, or approximately 14% incremental additional cost. By sizing the building today with additional space for expansion, U. S. EPA saves the costs associated with tearing out walls and re-working HVAC. In addition, the costs of re- mobilizing construction crews (including the need for additional foundation and concrete work) are avoided. Finally, by having the space for expansion already available, with the ability to add treatment capacity simply by placing additional treatment equipment into the existing building and tying the equipment into an existing treatment system, will minimize disruption to plan operation.

COMMENT: CBS is critical of U. S. EPA's decision to provide the interim system with utilities, an access road, and the expense of clearing and grubbing, and landscaping, and asserts that these "new" expense items are inappropriate and show that the interim system is really a "final" system.

RESPONSE: U.S. EPA's conceptual approach estimated $24,000 for the access road and $13,000 for clearing and grubbing of the site. The actual clearing and grubbing cost for an "8-A" firm was $62,000. The all weather access road's cost was $71,000. At the conceptual stage U.S. EPA did not consider power and utilities, such as natural gas and telephone, and had no provision for emergency power ($150,000 for a diesel generator). These expense are for the most part not new, but the were estimated incorrectly before the design was prepared. In addition, while these elements are durable, they do not transform this interim system into a final system. Rather, these are components that are compatible with both.

COMMENT: CBS continues to advocate its "interim approach" of a Cavity fed treatment qvq~m consisting of carbon filter bags placed in the stream bed. CBS also argues in favor of a "portable system" consisting of skid mounted treatment vessels. Alternatively, CBS appears to say that U.S. EPA's initial interim system as described conceptually in the 1998 Action Memorandum, is a workable solution.

RESPONSE: CBS's approach of"carbon sacks lying in the stream bed" is not workable, given U.S. EPA's objective of ensuring a protective interim removal action. The gravity fed system proposed by CBS would, by it's own admission, only be able to at best be able to treat the PCB contaminated water flowing from the stream at low flow levels. CBS's proposal also does not appear to make any provision for clogging of the carbon filter bag system (which would occur over time at low flow, and would be most acute during high flow events when sediment and PCB releases are greatest and PCB capture is most important), and completely ignores the higher mass levels of PCBs that are discharged during storm events and that pose the greatest human health and ecological risk to Clear Creek. The second proposal presented to the U. S. EPA on June 1, 1999, again continues to show an indifference toward the level of protectiveness toward the Clear Creek ecosystem. It is unlikely that the skid mounted system suggested by CBS would be able to address the threats posed by high levels of PCBS that could be released during storm events while the remediation of Lemon Lane is underway, or thereafter. This is because the system proposed by CBS is not adequately sized because it does not inadequate provision for capture and storage of PCB contaminated spring water during high-flow storm events. Thus, large quantities of PCB would continue to be released to the environment and eventually into Clear Creek.

COMMENT: CBS criticizes U.S. EPA's "flexible design" and compares U.S. EPA's interim design approach as favorable to the flexible design adopted in the 1999 Action Memorandum. The flexible design as approved by EPA, has combined the initial guidelines of the project which were "1,000 g.p.m. of water treatment using basic water treatment technology and a storage of 2 acre feet." Outside of adding 2 acre feet of storage for the reasons of the "protectiveness of Clear Creek" as outlined above, U. S. EPA has stuck to those initial guidelines.

RESPONSE: A final design will be approved as part ofthe final treatment system. The final treatment decisions will be made as part of the second operable unit for the Lemon Lane remedial action. As part of the remedial action decision making, all applicable, or relevant and appropriate requirements (ARARs) (clean up laws, rules, and regulations) establishing, among other things, discharge criteria will need to be considered and satisfied (or waived) in connection with selection of the final water treatment approach. The current system is an interim "flexible" approach intended to address the most pressing problems of minimizing risks during the source control measures at Lemon Lane, and controlling releases that occur during storm events. The final water treatment approach may include various water treatment technologies that can be best described as "ultra filtration." This technology, will involve either (or both) reverse osmosis or flocculation/coagulation, in addition to the processes that will be in place. It is anticipated that such additional measure may be necessary to achieve ARARs. For any new technology to be implemented, certain piping, power, and building requirements will have to be met. It makes sense design and build to those requirements now where significant costs savings will be realized and the cost of retro-fit avoided. The capital cost of a 10" pipeline does not differ significantly from that of a 12" pipeline. This also holds true for added electrical capacity and also square feet of building space. These three items demonstrate that the Illinois Central Spring water treatment plant will be able to transition from a "flexible to a final" plant with little or no impact on its operation and with little additional costs.

COMMENT: CBS argues that a portable system, one contained on either flat-bed trucks, or enclosed in self contained trucks would be more suited to a interim plant, as the system can be picked up and moved to a more desirable location; i.e. Quarry Springs or Lemon Lane Landfill.

RESPONSE: It is true that U.S. EPA's system cannot be readily moved en masse to a new location. However, all of the equipment in the process was designed with portability in mind, as witnessed by the many pipe connections which were selected for easy disassembly and reassembly if so desired. Furthermore, the storage tanks are bolted steel tanks that also can be moved, as can the actual building itself. Further, CBS has not provided any engineering work on its version of a portable system. Accordingly, it is unclear whether this "system" will even meet the "low flow" discharge standards. Absent a more defined system, it is not even apparent whether the "system" will work in winter. Emergency power also is not provided for.

COMMENT: CBS states that the Illinois Central Spring location might not be the location where the final remedy will be located. CBS asks why U.S. EPA building its "flexible remedy" at that location pending CBS's final Groundwater and conduit study.

RESPONSE: The location of the Illinois Central Springs plant is not at the location of Illinois Central Spring. Rather, the water is being pumped from the Illinois Central Spring to the location of the plant. The same scenario can be applied to any water that might emerge at Quarry Spring or even at the site of Lemon Lane Landfill - it can be conveyed to the treatment plant and treated there. A simple receiving sump or receiving sumps, just like the one to be constructed at Illinois Central Spring can address this issue. Further, the availability of the selected plant site was propitious. The fact that the City of Bloomington owned a piece of property that it was willing to make available without cost to U. S. EPA, that was isolated, the right size, and that was easily accessible for construction, are among the reason for the plant's location. The quarry Spring location advocated by CBS property is private property. Thus, long acquisition negotiations and/or condemnation proceedings could be anticipated. Further, given the area and nature of the Quarry Spring location it is likely that the City and/or the residents might not want either the plant or the construction traffic there.

COMMENT: CBS argues that its claim that only low flow discharges standards should be met does not necessarily indicate a lack of confidence in their portable system. It suggests that a portable system simply would not be able to handle a high flow, much less be able to conform to the strict discharge standards being enforced.

RESPONSE: Contrary to CBS's claim, CBS's assertion that only low flows need be addressed demonstrates that its portable system simply would not be able to handle a high flows, much less be able to conform to the strict discharge standards being enforced. A portable plant of the kind CBS suggested in its June 1, 1999 proposal, is not the right application where the protection of Clear Creek is the goal. CBS's portable system might remove PCBs coming from the spring during low flow, but low flow is not the concern. The turbidity of the spring water increases as the severity of storm events increase, thus increasing PCB concentrations during high flow. This is the period where the operation of the plant is most critical from the standpoint of protecting Clear Creek. U.S. EPA's "flexible design" plant will handle high flow where CBS's portable plant cannot. That is why CBS will not agree to a high flow standard. It appears to be a simple matter of CBS not wanting to incur the expense associated with treating high flow.

The 1,000 g.p.m. treatment capacity of the CBS portable plant is the same 1,000 g.p.m. that the EPA plant will treat. The difference is that the EPA plant will be able to concurrently send an additional 5,000 g.p.m. to storage for treatment after the storm surge diminishes (thus capturing and treating 70 percent of a 25-year storm event). The CBS plant merely by-passes to Clear Creek and, thus, all of the PCBs contained in the suspended sediment that is known to emanate from the spring during a storm, goes untreated to Clear Creek. To stop the treatment process at 1,000 g.p.m. without a storage and settlement train in the treatment process will allow more PCB sediment to enter Clear Creek during one storm event than CBS's low flow portable plant could capture in many months of operation at low flow.

Protection of Clear Creek is essential from en ecological and human health standpoint. Water samples collected by CBS in November 1997 at ICS, Quarry Springs and Clear Creek at Country Club Road was found to have PCBs, respectively, 11,000, 44, and 23 times the 0.79 parts per trillion PCB ambient water quality criteria. In the latest sampling event for fish on August 19, 1997 in Clear Creek show elevated levels of PCBs in fish. The August 19, 1997, analysis of rock bass, largemouth bass, and suckers from Clear Creek revealed that PCB fish tissue levels averaged, respectively, 18, 33, and 65 times those derived (0.025 ppm) from state ambient water quality criteria. Edible-sized fish tissue results from the August 19, 1997 analysis show rock bass with a mean concentration of 446 ppb PCBs, spotted sucker with a mean concentration of PCBs of 1620 ppb and largemouth bass with a mean PCB concentration of 872 ppb. The Indiana Department of Environmental Management and the Indiana State Department of Health have placed a fish consumption advisory on Clear Creek for PCBs. Clear Creek is one of only ten waterways out of a total of 104 in Indiana in which all fish from the waterway are under the most serious classification of advisory, a Level 5, which states that fish caught in these water should not be eaten in any quantity at any time because of high levels of PCBs (greater than 1.9 ppm) within the fish. Creek chub, a major food item for wildlife, have PCBs ranging from 0.4 to 42 ppm PCBs, considerably above levels associated with reproductive effects in fish eating mammals such as mink, otter, and racoons.

Given what is known about the pattern of high PCB mass discharges occurring during high flow events, i.e. storms, it is critical that any treatment system be able to continue to operate even if there is a power outage. Accordingly, U. S. EPA's design provides that standby emergency power is included in the plant. CBSis not willing to be held to a high flow discharge and, accordingly, isn't concerned about by-passing their system at 1000 g.p.m. Standby power is not considered or included by CBS.

The major point of contention between the U.S. EPA and CBS systems revolves around whether to treat the spring emergence to high flow or to low flow. U. S. EPA has concluded that to achieve the maximum protection to the Clear Creek ecosystem, you have to treat to high flow. CBS contends that with the limited data that is available, it makes sense to only treat low flow. The U. S. EPA responds with the reasoning, that to spend $1 or $2,000,000 (the Tetra Tech number that CBS has used over and over) to treat low flow, doesn't make any sense, because the main reason to build the plant in the first place, is to reduce the PCB threat that only occurs at high flow. This concept was accepted early in the design phase by U. S. EPA, after which it was a simple matter of how to best achieve that goal. U.S. EPA's approach from the start of engineering activities is that the operational plant should be designed with the flexibility to be able to accept any "ultra filtration" technology with minimal interruption to the operational plant.