Complete Report for Printing

Comments on the Draft Feasibility Study Lower Fox River and Green Bay PCB Cleanup Submitted 14 January 2002  To Clean Water Action Council of N E Wisconsin By Donna Boreck Geologist Highlights Human Health The 1-ppm target level is not protective of human or ecologic health. An assumption is made that the remaining PCB concentrations will be managed by natural recovery -- an uncertain gamble. Capping in the Lower Fox River Capping in conjunction with natural recovery has been proposed as an alternative. There are a number of weaknesses in the proposal: 1.  WDNR (Technical Corner--Capping, July 2000) presented guidance on when to cap. The guidance included capping in an area where currents are no greater than 0.15 feet/sec. Average current velocities in all reaches of the river vary from 0.25 to 1.23 feet/sec. 2.  WDNR guidance included that capping should be done in areas where the maximum 100-year flood current is no greater than 0.7 feet/sec. Based on average current velocities for the different reaches of the river, the 100-year flood current may exceed the 0.7 feet/sec in all reaches of the river. Actual values for the 100-year flood current for each reach need to be determined.  3.  The proposed capping project has been described as the …"biggest ever attempted in the U.S.". Anytime an engineering design is sized larger; there are new challenges and risks associated with increasing the size and level of complexity of the design. Large scale PCB cleanup requires the best available proven technology--dredging and removal of PCBs. 4.  Capping requires long-term monitoring and maintenance. It may only take less than ten years to place the cap, but the proposed capping will require significant time, expense and man-hours to monitor and maintain the effectiveness of the cap--longer than the 60 year time frame proposed by the panel to dredge the river and bay. Modeling Many conclusions in the RI/FS are based more on modeling and less on empirical results from monitoring, data gathering, etc. Each model has its limitations. Making a decision based on model results is appropriate if the limitations are taken into account in the final decision. With what is empirically known about PCB contamination in both the river and the bay, deciding not to act, based on modeling results (i.e. leaving the PCBs in the River or Bay to natural recovery) is inappropriate. The method used to determine the 1-ppm extraction level is not appropriate for a contaminant like PCB. The method, similar to what is done to determine in-place reserves for mineral commodities, seems to focus more on minimizing volume of sediment extracted or cost of remediation and less on what needs to be recovered to protect human health.  Recovery of PCB contaminated sediment will not be 100%. Using the recovery factor from Deposit N (20%), recovery of the 1ppm sediment would be approximately 79%, not the 99% modeled for Zone 1. To maximize recovery, remediation efforts need to focus on dredging and removing as much of the deposit as possible--not limiting recovery to sediment at a modeled 1-ppm action level. Average Values Quoting average values for parameters such as current velocity and wind speed gives a false sense of security in visualizing sediment transport and deposition in the river and bay. PCBs and other contaminants move in the system by events that are not 'average'. 1.  Quoted in the RI/FS, "…Based on the seasonal variations in PCB concentrations, it is estimated that more than 60% of the PCBs transported over the DePere Dam occurs during 20% of the year, when discharge is at it's greatest." 2.  The average velocity for Zone 1 is 0.25 feet per second. The velocity pegged for erosion of sediments in the Lower Fox River is 0.3 feet/sec. Below that point, sediments can be deposited. Above that point, resuspension of sediments can occur. Velocities recorded at USGS Stream Gage along the Lower Fox River revealed that actual velocities can vary significantly from the 0.25 feet/sec average and the 0.3 feet/sec erosion velocity-- hourly, daily and over periods of weeks.  Green Bay -- Remediation: Green Bay is not quiet water. It is a dynamic system where, based on the present footprint of PCB contamination, suspension and resuspension is ongoing.  Green Bay has a diverse bottom-dwelling community that will both negatively affect burial of PCB-contaminated sediment and will continue to provide a contaminated food source to fish and other wildlife. Worm species reported in Zones 2 and 3a in Green Bay can effectively churn and expose to the water column up to 6 cm of sediment on the Bay floor.          Green Bay is now a rich resource of PCBs and an independent source of contamination to both Lake Michigan, the surrounding land, and, via volatilization followed by deposition, to locations far from the bay area. Without remediation, Green Bay will be a source of PCBs for years. Ironically, if Green Bay is not remediated, it can help to re-pollute Zone 1 of the Lower Fox River, limiting efforts and wasting remediation dollars.  General Comments The 1PPM 'Knee' Area of concern: The 1ppm PCB target extraction level is not protective to human or ecologic health. The 1 ppm 'knee' has no health-based rationale to it. An assumption is made that the remaining PCB concentrations will be managed by natural recovery, an uncertain gamble. Discussion: See the comments of Dr. Foran on www.foxriverwatch.com.  Is it ethical to use the 1 ppm (1000 ppb) 'knee' philosophy to clean up a substance that poses risk to human health and to a wide range of wildlife both in and out of the Lower Fox River and Green Bay?  Capping in Lower Fox River Area of Concern: The capping, as proposed, does not effectively address the problem of PCB contamination in the Lower Fox River. Even if it is done right, capping is a high-maintenance temporary fix for a long-term problem. Discussion: Capping in conjunction with natural recovery has been proposed as an alternative to the remediation actions proposed in the RI/FS. There are a number of weaknesses to using capping in the Lower Fox River. The following comments are based on what is presented in an article posted in the Green Bay Gazette on December 5th, 2001: The article noted that several designs would be incorporated into the cap to be used in the river. From a WDNR publication on Capping dated July 2000, the requirements for capping include an area where "currents are no greater than 0.15 feet/second". Average current velocity for Zone 1 is reported at 0.25 feet/second. Other reaches of the river reportedly have a higher average velocity (0.37-1.23 feet /sec).   WDNR (2000) also noted that capping should be done in areas where the maximum 100-year flood current is no greater than 0.7 feet/sec. I do not know what the 100-year flood current is for Zone 1, but average is 0.25 feet/sec (approximately 1/3 of the proposed 100-year maximum). If a 100-year discharge is 5-6X greater than the average discharge (as is true at the Rapide Croche gauging station) for Zone 1 (or any reach along the Lower Fox River), I question if Zone 1 or other reaches along the Lower Fox River meet the 0.7 feet/sec flood current requirement.    According to Dr. Reible, an expert on capping of contaminated sediment, the technique…"has never been tried in the United States on a scale like that proposed for the Fox River. I don't think there is any doubt this would be the biggest…". If this capping project is the biggest ever attempted in the United States, it is in the area of 'unproven technology'. There are risks and complications that may come up with 'super-sizing' any engineering technique and that is a risk that ultimately is handed to the people of Northeastern Wisconsin. Remediation of the large volume of PCBs present in the river and Bay requires the use of the Best Available Technology -- dredging and removal of the contaminated sediment.   Capping requires maintenance and long-term monitoring. This is especially true in a riverine environment where the cap is exposed to failure from erosion or other river dynamics. Monitoring includes measurement of cap thickness, sediment chemistry, and observations of biological recolonization. Monitoring must include evaluation of zones in the cap that may need rebuilding. PCBs do not break down quickly. Cap monitoring would require significant expense and man-hours for an extended period of time (greater than 40-60 years projected by the panel) to guarantee the effectiveness of the cap. Removal of the PCBs from the river and bay is the most cost-effective means of improving health of future generations.    Capping ties the hands of residents and elected officials in a number of areas including land-planning, economics, and recreation. The action will continue to limit use for over 100 years or more.   The study recommends that capping be constructed to a standard that would enable it to withstand water forces three-times what would occur in a flood so severe it would only happen on an average of once per century. A 100-year-flood (a confusing term) is a flood that has a 1% chance of occurring every year. There is nothing magic about a flood event that happens to us only every 100 years. The same flood event could occur multiple times in five years. A larger flood event (250- to 500-year) could also occur in that same five years. Use of a term like a 100-year flood event gives a false sense of security.  Modeling Area of Concern: Many of the findings in the RI/FS are based on modeling. Each step in the modeling process has its limitations. Making a decision to act based on model results is appropriate only if the decision takes into account the known limitations of the model. Making a decision not to act (i.e. proposed natural recovery and monitoring) based on model results is inappropriate.  Discussion: The draft RI/FS is based mainly on the results of a chain of models run to determine potential levels or effects of different parameters. Even the best modeling has its weaknesses. For the draft RI/FS, each step in the modeling process has its limitations. The following are examples:   MODEL UNCERTAINTY Lower Fox River Sediment Bed Properties-Inverse Distance Weight Method. The results are sensitive to what value is used for the radius of influence. A larger radius gives more coverage, but a smaller radius may show more accuracy for specific deposits. There may be an increase (or possible decrease?) in estimated PCB concentrations with the larger radius of influence.  GB-SED Green Bay Sediment Transport Model The model does not include data to assess the impact of individual storm events or tributary loading. There is some uncertainty in specification of the settling velocity function, resuspension potential parameters and shoreline erosion. Settling function may not be applicable to all sites. Rususpension potential parameters were obtained from shaker studies on only one core. GB SED does not account for internal production of solids, an important component of the sediment mass balance in the bay.  Computation of Internal Solids Loads in Green Bay and Lower Fox River. Listed areas of uncertainty include scarcity of data, representativeness of data, scaling of data, uncertainty in conversions and uncertainty in constants. Other areas of uncertainty include uncertainty in extrapolating data and in phosphorus loads. "Monte Carlo simulations show that parameter uncertainty and sample variability together imply a normal standard error of about 25% in predicted BIC (biotic carbon loading) for Green Bay and a normalized standard error of about 62% and 64% for predicted BSS (biotic suspended solids) in the Lower Fox River, above and below DePere Dam, respectively (Tech Memo 2c, 1999, p 26)".  Each step in the modeling process brings in a level of uncertainty. It is important to bring into focus the uncertainty when evaluating the results and making a decision to take action. But, with what is empirically known about PCB contamination in both the River and the Bay, deciding not to act based on any modeling results, is inappropriate.  Modeling Area of concern: In principal, the method used to determine the 1 ppm extraction level is not appropriate for a high risk contaminant like PCB. PCBs biomagnify in the environment and threaten human health and our ecology. Lower levels of PCBs (below the 1ppm "knee") do not equate to acceptable risk. The 1 ppm recovery goal seems more focused on minimizing volume or cost and less focused on what needs to be recovered to minimize risk to human health. Discussion In the RI/FS, a method was used to determine the volume of in-place PCB contaminated sediment and the percentage of the total deposit that would be extracted . According to the modeling, in many stretches of the river, a large volume of the PCB contaminated sediment will be recovered at the 1000 ppb (1 ppm) level. The work leads to the assumption that trying to extract the remaining in-place PCB contaminated sediment is not worthwhile. The 1 ppm value is what has been called the `knee' in recovering PCB. Below this knee, recovery of smaller amounts of PCBs would require digging out more volume of sediment in the river. The action will be more costly per pound or kilogram of PCB recovered and processed.  The method is similar to a standard reserve study that would be done for industrial minerals, metals, and other materials that are to be extracted from the earth. A reserve study is cost-based and cost-driven and focuses on how much you can get per pound or ton of the commodity. You extract what you can for a profit and leave the remaining lower grade material in-place, either for future extraction when the mineral's price goes up or as waste I see many parallels to how the PCBs have been handled. But, in this case. we are not dealing with a material that is beneficial to mankind. We are dealing with a pollutant that, even at lower levels, can biomagnify in the system. Despite its "lower volatility", PCBs can be mobile within the environment for a long time. The 1 ppm recovery goal seems more focused on minimizing volume or cost and less on what needs to be recovered for human health. Modeling Area of Concern: Recovery of any material or mineral is never 100%--Recovery of the PCB contaminated sediment will not be 100%. The recovery of minerals from a deposit can be 60% or less of the volume of mineral in-place. In Deposit N, approximately 80% of the PCBs were recovered and 20% remained in-place. Successful dredging of any reach in the river does not guarantee that all of the PCBs calculated to be in-place are taken out. To maximize recovery, remediation efforts need to focus on dredging and removing as much of the deposit as possible. Cutting off recovery at a set target level will further lower recovery of in-place PCBs. Discussion: Recovery of any in-place substance in the earth is never 100%. A recovery factor for minerals can be 60% or lower. In Deposit N, approximately 80% of the mass of PCB (calculated to be in-place) was removed during dredging. Approximately 20% remained. The dredging operation hit hard rock at the base of the soft sediment which prevented them from digging further. The remaining PCBs are believed to be tied-up in sediment that has filled fractures in the rock. In Deposit 56/57, a total of 6600 lbs of PCB were projected to be in-place. During the 1999 demonstration project and 2000 demobilization project, an estimated 1,441 pounds or 22% of the PCB sediment was recovered. The project was plagued by weather, large debris in the river and a number of other factors.  Based on modeling, if contractors recover the 1000 ppb (1 ppm) sediment at the De Pere to Green Bay reach, they project they would recover 99 percent of the PCBs calculated to be in the reach. Yet, projected recovery may still be lower. If we use Deposit N's recovery factor, the actual recovery may be closer to 79%.  They are planning to over-dredge the deposit as a safety. But, setting PCB recovery on the '1ppm knee' target concentration is aiming too high. Even if contractors over-dredge, the over-dredging may not be sufficient to actually recover the volume necessary to remove contamination at the 1 ppm target level.  The presence of PCB is a human health and ecological health issue. We need to be conservative and shoot lower than the 1ppm target level to maximize both recovery of in-place PCBs and the long term benefit to human health and the environment. PCBs Don't Move by What is Average Area of Concern: Using average values in the RI/FS gives a false sense of security in visualizing PCB sediment transport or sediment deposition into Green Bay. Discussion: In the report, average values were often quoted for wind speeds, currents, etc. Use of average values is scientifically valid in looking at modeling for steady state conditions. But steady state does not always reflect what is actually going on, sometimes daily.  In the draft RI, the findings of Fitzgerald and Steuer (1996, RI p 2-5) were quoted. "…Based on the seasonal variations in PCB concentrations, it is estimated that more than 60% of the PCBs transported over the DePere Dam occurs during 20 percent of the year, when discharge is at its greatest."  Average values for different parameters in Zone 1 are given below: Zone 1- Lower Fox River -- average discharge. 4,300 cubic feet/sec (122 cu m/sec). Zone 1-Lower Fox River -- average velocity. 0.25 ft/sec (0.08 m/sec).  The velocity pegged for erosion of sediments in the Lower Fox River is 0.3 feet per second. On October 14th, real-time discharge varied from -5000 to +11,000 cfs at USGS Stream Gage 040851385 (Oil Tank Depot at Green Bay). The real-time data was taken over a time period from 1200 am to 830 am. During that same period, velocity varied from -0.62 to +1.07 feet/sec. The velocities recorded on the two Acoustic Velocity Meters (AVMs) exceeded 0.30 ft/sec 65% of the time during that 8 1/2 hour period. Higher flow levels were sustained for up to 2 hours and 45 minutes. Over a 14 day period from Oct 28th through November 10th 2001, the velocity varied significantly with an average of 0.61 feet/sec recorded at the lower AVM. Discharge also varied significantly with an average discharge of greater than 6000 cu ft/ sec. On October 29th, both upper and lower AVMs pegged near +2.0 and -2.0 feet/sec. Discharge reached 20,000 cu ft/sec. Reportedly, there was a significant wind storm during that time that affected the flow velocity during this late October-early November time period.  The data sets are real-time and considered provisional, which means the values may have to be adjusted for some errors in equipment or other conditions. The data does reflect how much values can vary from 'average'. With both data sets, the value of 0.3 feet per second was surpassed often. During a 14 day time period, the average value for the lower AVM was 0.61 feet/sec which surpasses the erosion limit of 0.3 feet/sec in the Fox River.  We cannot define the risk from PCBs by using average values. PCBs and other contaminants move in the system by events that are not 'average'. Green Bay -- Remediation Area of concern: Green Bay must be remediated and not left to natural recovery -- Green Bay is a dynamic system. Green Bay is not quiet water. Suspension and resuspension of sediments is possible and ongoing. Discussion: From the RI/FS, leaving the PCBs in-place and allowing the Bay to recover naturally would eventually allow for dilution or breakdown of the PCBs to a level where they would no longer affect wildlife. Natural recovery also would include burying the PCBs with clean sediment sources from riverine and bank erosion and input from Lake Michigan. The theory only takes into account a part of the natural processes active in Green Bay. Green Bay is a dynamic system--it is not quiet.  Currents -- Information on currents for Green Bay was limited. From the RI/FS: Green Bay --- Current velocity east of Chambers Island to 1.1 ft/sec (0.35 m/sec) Current velocity west of Chambers Island 0.4 -0.8 ft/sec (0.12-0.24 m/sec) Current velocity Inner Bay to 0.4 ft/sec (0.12 m/sec) Barry M. Lesht and Nathan Hausley (1987) conducted a study of Near Bottom Currents and Suspended Sediment Concentration in Southeastern Lake Michigan. Their findings were: Currents near the bottom were well correlated with surface winds.   At a 28 meter depth, they inferred from their results that local resuspension could occur approximately 20% of the time.   The critical mean flow speed for resuspension at 0.7 meters (2.3 feet) above the bottom was approximately 0.18 m/sec (~0.6 ft/sec). This value was for a bottom of silty sand.  It is not known how closely Green Bay would match the findings of Lesht and Hausely. But, currents east and west of Chambers Island can exceed the 0.6 feet/sec flow speed for resuspension. It is not known what bottom currents would be in a major storm. Wind speeds -- Average wind speeds reported in the RI are at or below 19 mph . (specifically, wind velocity S-SW 37% of time 6-19 mph (10-30 km/hr)) These values agree well with other published sources. Again, `average' does not define risk of remobilizing PCBs into the water column. According to ESRI hazard maps (www.esri.com/hazards) for the Green Bay area, wind speeds in the area of 60-80 miles per hour have been reported to occur post 1970. On the Door Peninsula, one value has been reported within the 120-140 mph range. In the RI on page 3-43, the following research finding was quoted: "… Moderate to strong winds are the most important factor for bay sediment resuspension and occur, on average, every seven days on the Great Lakes. "  Sediments -- In the Bay, sediments have a greater chance to settle and compact than in the Lower Fox River. PCB-bearing sediments are often very fine particles that tend to be cohesive once they settle in-place. Yet, once the fine sediments are resuspended, the particles can be transported by currents for a long distance before they settle again. According to research, even when fine particles flocculate, the flocs can be light, unstable and break apart easily, keeping the particles in suspension and transportable for long distances.  Green Bay is a dynamic system that will continue to transport sediments and ultimately PCBs within the Bay, out to Lake Michigan, and back up the Lower Fox River. Natural recovery requires a quiet environment that will allow for continual burial of the contaminated sediments undisturbed by other factors. Green Bay does not offer that environment. As much as we would like the PCB contaminated sediment to 'stay put', it may not oblige.  References ESRI, Inc. Online Hazards Map -- Wind Hazards. Green Bay, WI area. 2001. At www.esri.com/hazards. Lesht, Barry M. and Nathan Hausley. 1987. Near Bottom Currents and Suspended Sediment Concentration in SE Lake Michigan. Journal of Great Lakes Research ,13(3): 375-386). Tsai, Cheng-Han, Sam Iacobellis and William Lick.1987. Flocculation of Fine-Grained Lake Sediments Due to a Uniform Shear Stress. Journal of Great Lakes Research 13 (2): 135-146. Reineck and Singh, Depositional Sedimentary Environments. 2nd Edition, Springer Verlag, 1980, 549pp. Green Bay -- Remediation Area of concern: Green Bay has a diverse bottom-dwelling community that will be affected by the PCBs. The RI reported a benthic community in Green Bay which included unidentified species of worms. A characteristic of worms as well as other bottom dwelling creatures is their tendency to burrow. The burrowing can turn over and disrupt the PCB contaminated layers. If the contaminated sediment is buried, bioturbation may bring buried contaminants to the surface. Lastly, the burrowers are a food source and can continue to bring PCB into the food chain long after the contaminated sediment is buried. Discussion: If the currents don't stir up the bottom sediments, other factors may. The RI reported a benthic community of oligochaetes among other organisms. The oligochaetes were described as unidentified species of worm. According to Lauritsen and others (1985), in Green Bay, tubificids were the dominant oligochaetes found (usually >80%) at shallow depths of <40 m. The tubificid Limnodrilus hoffmeisteri --a eutrophic species abundant in Green Bay -- was suggested as an indicator for pollution.  Another article by White and others (1987), quoted a maximum feeding depth of 3-6 cm for tubificids, although the organisms in densely populated areas may burrow deeper to compensate for lack of room.  Even in quiet water, the presence of burrowers can turn over and disrupt the sediment (bioturbation) or otherwise provide access to lower buried layers of PCB contaminated sediment. The burrowers are a food source and can continue to bring PCB into the food chain long after the contaminated sediment is buried by clean sediment.  The worms, especially Limnodrilus hoffmeisteri, maintain themselves in a high carbon contaminated environment. The most effective way of preventing spread of PCB contamination from sediment reworking and/or through consumption of the worms as a food source is to remove the source of the PCBs.  References: Lauritsen, Diane D, Samuel C, Mozley, and David S. White. 1985. Distribution of Oligochaetes in Lake Michigan and Comments on Their Use as Indices of Pollution. Journal of Great Lakes Research 11 (1):67-76 White, David S., Patricia C. Klahr and John A. Robbins. 1987. Effects of Temperature and Density on Sediment Reworking by Stylodrilus Heringianus (Oligochaeta: Lumbriculidae). Journal of Great Lakes Research 13 (2): 147-156 Green Bay -- Remediation Area of concern: Green Bay has a large volume of PCB in-place. The Bay will continue to be a source of contamination for an undetermined amount of time. The contamination includes exposure to wildlife and humans in the general area of Green Bay, transport of PCBs to Lake Michigan, and volatilization of PCBs into the atmosphere. Once in the atmosphere, the PCBs can be redeposited onto land and water far from Green Bay. Although the PCBs are in lower concentrations in the Bay, they are recoverable. If they are not recovered, the PCB contamination will spread. Discussion: Although the Green Bay sediments are not as contaminated with PCBs as the Fox River, the sediments are and will continue to be a source of PCBs to Green Bay, Lake Michigan, and to Wisconsin and adjacent states. The sediments may be lower in PCBs than those slated for removal from the Lower Fox River. But, the sediments have enough PCBs in them to be a concern to wildlife in the area. The safe drinking water level for wildlife is 0.12 nannograms per liter (ng/L, 0.00012 ppb). Filtered water samples taken in Zone 3B (39 filtered water samples) varied from 0.5 ng/L to near 4 ng/L. All 39 samples exceeded the safe drinking water level for wildlife. These are low values when you compare with the higher values coming over DePere Dam, but they are still valid and they are still above the level of safety for wildlife. Analysis of the particulates filtered from the sampled water also resulted in values lower than the highest values reported in the Fox River. The values range to 7 ng/L. But, they still represent a mobile source of PCBs available for uptake or for transport.  From the RI (Section 7.4, page 7-16), Green Bay gives away more PCBs than it receives from other sources. Green Bay transports an estimated 270 lbs of PCB annually into Lake Michigan. Green Bay's annual PCB contribution to the atmosphere through volatilization is estimated at from 287 to over 1000 lbs. According to USEPA (2001), PCB is recycled through the environment through volatilization from ground surfaces (water and soil) into the atmosphere followed by removal from the atmosphere by precipitation or by sedimentation. According to Atkinson (1996), the estimated residence time for particles in the atmosphere may be from ~5-15 days with more highly chlorinated arochlors in the atmosphere for up to ~30 days.  The Lower Fox River supplied Green Bay with a substantial reserve of PCBs. But Green Bay is now an independent source of pollution. Contamination can be spread to Lake Michigan, via volatilization to distant areas and back to the area near the mouth of the Lower Fox River. Leaving Green Bay to natural recovery would be costly in terms of human health, local and regional environment and the future. References: USEPA. EPA Fact Sheet on PCB--Technical Drinking Water and Health Contaminant Specific Fact Sheet. Updated 12 April 2001. From www.epa.gov/OGWDW/dwh/t-soc/pcbs.html. Atkinson, Roger. Atmospheric Chemistry of PCBs, PCDDs, and PCDFs in Chlorinated Organic Micropollutants. Ed.s R.E. Hester and R.M. Harrison Issues in Environmental Science and Technology No. 6. The Royal Society of Chemistry,. 1996, pp 53-72. Comments on the Draft Remedial Investigation Executive Summary   PAGE COMMENTS xx Almost half the total PCB mass in Green Bay is found in Zone 2. There have been questions on this finding. Even if the amount present in Zone 2 is less than the initial estimates, it does not dismiss the site from requiring remediation. Zone 2 is still at the interface between present development and the contaminated body in both the Green Bay and Lower Fox River.  xxii PCB concentration trends… generally appear to be decreasing over time as more PCB is transported downstream. As summarized in the RI (7-17), "In tissue sample, decreasing concentration trends have been observed but the rate of decrease has slowed significantly since the 1980s. Also, some fish species show stable or increasing tissue concentration trends. Therefore, the analysis completed as part of this effort are not suitable for predicting future trends". The above comment on decreasing PCB levels is not validated by the findings in the RI. xxii Soil eroded from the watershed mixes with and may further dilute PCB concentrations in the sediment. Implies a solution that may not occur and is not protective of human or ecologic health. PCBs in the sediments and water are at levels that exceed protective levels for both wildlife (specifically bethic life) and ultimately human health. The benthic fauna will continue to be at risk and can pass on contamination up the food chain for generations. General comments on Body of Remedial Investigation   PAGE COMMENTS 2-5, 3-26 PCB migration --Storm events. It was estimated that more than 60% of the PCBs transported over the DePere dam occur during 20% of the year when discharge is at its greatest (Fitzgerald and Steuer, 1996). On page 3-26, the results of three storms were summarized with flows over 25,000 cfs recorded. The RI also noted seiche events that can affect the river up to 7 miles upstream from the mouth. These events and other input reported in the RI/FS cast doubt on the notion that the Fox River/Green Bay environment is a viable location for natural recovery.  The cohesive nature of the fine-grained PCB sediments and armouring may not be enough to keep the sediments in-place during these or even lesser events. Effective capping in the river may also be difficult to implement and maintain. 3-40 Rework PCB migration--Non-storm events. It was noted by Velleux and Endicott (1994) that although the TSS load decreased in Zone 1, the overall PCB load in the river increased by up to 50%. In Sec. 5.5.2.1, …"Approximately 70-75% of the detected PCBs are particulate phase while the remaining 25-30% are in the dissolved phase". The finer grained cohesive sediments may take more sheer stress to get them into suspension, especially in a lake environment. But, once they are resuspended, they may travel a long way before being redeposited. Flocculation was given as a means of dropping PCBs out of the water column. But, because of how flocs form and act, the density of the floc may be close to water and settling velocity would be low. The flocs may be fragile, depending on how they are formed. The flocs may break apart easily.  Storm events can cause significant movement of PCB contaminated sediment. But after the event, the movement of PCBs in the water column may continue for a long period of time.  Given natural recovery, we may be diluting our problem, but we are sending the contamination over a widespread area. At present levels of contamination in Green Bay and the Lower Fox River, we cannot guarantee that the levels of contamination transferring to the surrounding areas are at levels that are protective of human and ecologic health. 3-42,43 Sediment consolidation. From the RI…"the upper-most layer of sediment was found to have consolidated in 7 to 14 days, … Moderate to strong winds are the most important factor for bay sediment resuspension and occur, on average, every seven days on the Great Lakes". With natural recovery--this may help dilution, but it does not say much for burial of the contaminated sediment.  As above, Green Bay may not be an appropriate environment to implement natural recovery based on the dynamics of the Bay and the level of PCB contamination in the Bay. Figure 3-3 Lack of information on currents in Green Bay. The information on Green Bay currents provided in the RI is limited to readings taken over a short period of time. The number of actual measurements also seems to be sparse. Before any decision is made on remediating Green Bay (and that includes natural recovery of the contaminants), it is recommended that more work be done to verify actual conditions.  To assume that the sediment will settle and be buried by clean sediment discounts other factors of nature that, at times, may dominate over sedimentation. As noted above, to allow for unnecessary spread of contaminants to surrounding areas can also be considered inappropriate.  4-3 Land Use. From the RI-- "Open agricultural land and forests/woodlands comprise between 65% and 94% of land use outside of Brown County". The section continued to discuss that the area is sparsely developed. Land use can change significantly in < 100 years--sometimes in < 10 years. PCBs are projected to be around > 100 years. Although development is presently sparse along the shores of the Bay, the land use and development around the Bay could increase significantly. What is now a low population area could have a much larger population in 50 years.  Decisions on remediation along the River and Bay need to take into account a possible increase in human development over the next 40-50 years minimum.  4-3 Bioturbation. One of the significant wildlife invertebrates listed are oligochaetes that inhabit the Lower Fox River and Green Bay . Specific species of worms were not identified in the RI/FS. A publication reporting research on oligochaetes occurrences in Lake Michigan/Green Bay (circa sampling in 1977) noted that the most abundant species at that time were Tubificids which made up > 80% of the total oligochaetes population in the Bay at depths < 40 m. From other research on oligochaetes, the burrowing depth for identified species of tubificids in Green Bay was between 3-6 cm. If the population increases, the worms reportedly compensate by burrowing deeper. Many of these species are attracted by the eutrophic conditions and higher TOC present in Green Bay, specifically Zones 2 and 3.  Assuming the worms identified in 1977 still predominate in Green Bay, bioturbation depth may be from 3 to 6 cm, possibly more depending on the density of the worm population in the area.  The PCB content of the sediment is from <100 to >1000 ppb. The TEL for benthic fauna has been set at 31.6 ppb (HH&ERA Table 7-11). The level of contamination is high enough to continue to adversely affect the benthic community for an unknown number of years. Natural recovery will be difficult--bioturbation can continue to bring buried contaminated sediments to the surface.  7-2 The 1ppm target level. The Risk Assessment conducted by ThermoRetec (2001) identified total PCB concentrations in sediments above 250 m/kg as a potential concern for at least 50% of all potential receptors. Yet, a 1000 m/kg target concentration has been pinpointed as appropriate. Because of potential effects on all communities, it is requested that the 1ppm recovery target be lowered to be more protective of health. 7-5 Gradual mixing/accumulating over PCB sediments. In the RI, "…more recent sediment loading is gradually mixing with and accumulating over PCB impacted deposits". First, from the results of the time trend analysis, the analysis completed as part of this effort are not suitable for predicting future trends. Second, the decrease in PCB content is reported for the upper 4 cm. Areas in the river reportedly have been eroded to 11-18 cm depth.  The 'gradual mixing/accumulating over PCB sediments' comment is not justified given the technical findings presented in the RI/FS.  7-11 1 ppm target for recovery in Green Bay. "Considering only sediments with PCB concentrations greater than 1000 mg/kg reduces the mass and volume estimates…" As noted above, at 250 mg/kg, there is a potential concern for over 50% of potential receptors. The 1ppm level will leave approximately 70% of the projected contamination in place. The 1 ppm target for recovery in Green Bay is not based on health. 7-16 Green Bay as source of PCB contamination. The overall PCB flux through the Lower Fox River and Green Bay system includes estimate losses of 270 lbs per year into Lake Michigan and volatilization of PCBs from Green Bay surface waters at from 287 pounds to 1100 pounds.  Green Bay is now an independent source of PCB to the surrounding area. It is requested that the regulators reconsider taking action (over and above natural recovery) to remove PCBs from the Green Bay. Comments on the Draft Feasibility Study Executive Summary   PAGE COMMENTS 3 Monitored Natural Recovery. From the FS, " A long term monitoring program would be implemented to ensure that sediment, water, and fish tissue PCBs would decline over time". A question--if PCB levels do not show improvement over a time of ten to twenty years--what then?  If the situation does not improve, what action will be implemented to speed up recovery? If actions are required at a later date, they will most likely be more expensive than if removal were conducted now.  Figure 4 Comparison of Human Health Protectiveness by Action Level--All Reaches. The results show that the 10- or 30-year criteria are reached with remediating to the 125 to 250 action levels. In some cases, these action levels are being considered. In others they are not.  The reason for the cutoff seems to be based more on limiting the volume being extracted and less on concern for human health.  General Comments on the Feasibility Study   PAGE COMMENTS 2-39 Large Mass of PCBs in Fox River and Green Bay. Given the losses to the surrounding area either to Lake Michigan or through volatilization, the " PCB mass located between the DePere Dam and Chambers Island is so large, that, at these lower rates of loss, a large mass of PCBs will remain in these sediments far into the future"(2-39). It was also reported that the surface area for Green Bay is a significant volatilization pathway. Modeling results show that RAOs will not be reached given the time constraints and 500ppb and 1000 ppb action levels.  Because of human and ecological health, it is requested that the EPA reconsider removal of sediments to safe action levels from all reaches including Green Bay. 2-48 Time Trend Analyses. In the Executive Summary and other parts of the report, it is reported that sediment PCB levels and levels in fish are declining. The analysts record in a number of areas in Section 2.6 that there is uncertainty to the hypothesis. From the FS …"the river, its sediment, and its species may be experiencing an arrest or reversal of such a decline."  The text in the executive summary does not reflect the uncertainty noted by the analyst. The decrease in sediment levels are reportedly for the upper 4" of sediment. PCB levels below have not shown a trend toward decreasing PCB levels. In some cases, the trend is for increasing PCB levels in the subsurface sediments.  Sediments at 4" and below are susceptible to erosion, which would reverse the decline in the eroded area and allow for re-exposure of benthic organisms, fish, and wildlife to higher concentrations of PCBs. 5-1 Surface Weighted Average Concentrations rely on natural processes. From the report--cleanup to a higher concentration may be protective if natural processes can be relied upon to return sediment COC concentrations to protective levels in a reasonable time frame.  They are relying on sedimentation to bury or dilute PCB levels in sediments. Sedimentation is only one of several processes that is ongoing in both the river and the bay. Erosion, resuspension, bioturbation, disturbance by plant growth, human activity can all re-expose contaminated sediments to the water and species.  Relying on natural processes to bring the sediments to protective levels requires that the sediments support a concentration that is close to protective levels. In the Bay--where natural recovery is expected to handle the 1 ppm plus PCB levels--the difference between the 1ppm level and what is safe for aquatic species is significant. Natural recovery is not warranted for Green Bay and any other reach where the remaining levels are significantly above protective levels. A reasonable time frame--What is reasonable? Given the contamination levels, natural recovery may be a process that requires a century or more before protective levels are reached. In human terms, the time relates to five or six generations that will be adversely affected by PCB contamination. 5-6 PCB mass sensitive to action levels. They are proposing to base their removal on an action level -- maximize the weight and concentration of PCB to mass removed. In considering costs and available landfill space, this theory may seem valid. But the actual risk to humans and the environment seems to be lost in the calculations.  PCB removal is a protective issue. Although recovery to action levels may be considered proactive, there are a lot of ethical questions involving what remains and what it will do to both human and animal over time.  The method used to determine action levels and recovery of a mass parallels a time-honored method used by engineers to determine what will be extracted from the earth at what cost or given what equipment. The material handled often does not pose long term risk to humans and the environment. Here we are dealing with a man-made substance that is known to cause problems to man and the environment. At this time, it is affecting communities in-and-around Green Bay and the Lower Fox River. The principle of the FS should be to remove PCBs from the river and bay to a level that is protective --not remove what we want to remove and hope nature will take care of the rest. 6-6 Limited utility of MNR. On page 6-6, "…it (MNR) may have limited utility for the Fox River and Green Bay to be protective in a reasonable time frame because of : 1) limitations of natural dechlorination; 2) slow time trend decrease in PCB concentrations in fish and sediment; and 3) substantial fluctuations in sediment bed elevations that preclude long-term burial by cleaner sediment". MNR was retained for use only in combination with other methods. For Green Bay, MNR is being considered as the sole method for remediation. In the Appleton Capping proposal, MNR is being considered a main alternative for large reaches of river. Based on the comments in the FS, it is requested that MNR not be the sole or a major remediation alternative for either the Lower Fox River or Green Bay. 6-7 Dredging as an alternative. A review of case studies on dredging shows that dredging is the most tried-and-true method for PCB impacted sediment. Based on concerns of too-much-volume, dredging is being replaced by MNR, a method that is not proven to be protective of human and ecologic receptors at the level of contamination present in the Lower Fox River and Green Bay. Superfund requires Best Available Technology. In this case, dredging is proven and is the BAT. 6-10 Effectiveness of Institutional Controls. The effectiveness of institutional controls is only as good as the effectiveness of the communication and the willingness of the citizens involved to follow the advisories and restrictions. Language barriers and cultural issues can make implementing institutional controls difficult. As with MNR, institutional controls may not be as effective as we would like.  6-17 Uncertainty in the wLFRM model. It is noted that the model underpredicts the shear stresses and that higher erosional events may occur.  As the magnitude and temporal dynamics of settling and resuspension may be higher than modeled, uncertainty in the modeling needs to be taken into account in choosing technology and designing a remediation effort. 7-5 125-250 ppb Action Levels dropped from Green Bay. The action levels were dropped from consideration because "the large volumes of sediment precluded practical disposal options". The 250 ppm action level is still not considered protective for species.  It is requested that the decisionmakers reinstate, at least, the 250 ppm action level. 8-29 Higher Action Levels in Green Bay. As noted above, the lower action levels of 125 and 250 ppb were dropped from modeling and from consideration in Green Bay. At the 500 ppb or 1000 ppb, almost all of the RAOs were not met in the given time period. Under a complete technical analysis, it is important to include the 125 and 250 ppb action level to determine if the RAOs would be met at either of these action levels. Prematurely dropping the 125 and 250 action levels from analysis was inappropriate. Evaluation of only the 500 and 1000 ppb results does not give a complete data set to judge the effectiveness of different technologies. The decision was made to retain Green Bay for monitored natural recovery based on an incomplete analysis. It is requested that modeling be conducted at the 125 to 250 ppb level to complete the data set for review. Even without modeling, Green Bay, as a long term PCB source, needs to be remediated. It is requested that regulators reconsider the negative long-term impacts of leaving Green Bay PCB contaminated sediment to MNR. References Atkinson, Roger. Atmospheric Chemistry of PCBs, PCDDs, and PCDFs in Chlorinated Organic Micropollutants. Ed.s R.E. Hester and R.M. Harrison Issues in Environmental Science and Technology No. 6. The Royal Society of Chemistry,. 1996, pp 53-72. ESRI, Inc. Online Hazards Map -- Wind Hazards. Green Bay, WI area. 2001. At www.esri.com/hazards. Journal of Great Lakes Research 11 (1):67-76 Lauritsen, Diane D, Samuel C, Mozley, and David S. White. 1985. Distribution of Oligochaetes in Lake Michigan and Comments on Their Use as Indices of Pollution. Lesht, Barry M. and Nathan Hausley. 1987. Near Bottom Currents and Suspended Sediment Concentration in SE Lake Michigan. Journal of Great Lakes Research ,13(3): 375-386). Reineck and Singh, Depositional Sedimentary Environments. 2nd Edition, Springer Verlag, 1980, 549pp. Tsai, Cheng-Han, Sam Iacobellis and William Lick.1987. Flocculation of Fine-Grained Lake Sediments Due to a Uniform Shear Stress. Journal of Great Lakes Research 13 (2): 135-146. USEPA. EPA Fact Sheet on PCB--Technical Drinking Water and Health Contaminant Specific Fact Sheet. Updated 12 April 2001. From www.epa.gov/OGWDW/dwh/t-soc/pcbs.html. White, David S., Patricia C. Klahr and John A. Robbins. 1987. Effects of Temperature and Density on Sediment Reworking by Stylodrilus Heringianus (Oligochaeta: Lumbriculidae). Journal of Great Lakes Research 13 (2): 147-156. back to top

	Fox River Watch is a project of Clean Water Action Council 1270 Main Street, Suite 120, Green Bay, WI 54302  Phone: 920-437-7304, Fax: 920-437-7326  E-mail:  CleanWater@cwac.net

	CONTENT BY: Rebecca Leighton Katers WEB DESIGN BY:  DataScouts WEB HOSTING BY: Doteasy