PUBLIC HEALTH ASSESSMENT
PADUCAH GASEOUS DIFFUSION PLANT (U.S. DOE)
PADUCAH, MCCRACKEN COUNTY, KENTUCKY
ATSDR received comments on the Paducah Gaseous Diffusion Plant (USDOE) Public HealthAssessment, Public Comment Release (March 30, 2001), from 18 individuals, organizations, andagencies. We thank all of those who took the time to comment. We also received additionalcomments at our public meeting. This appendix includes a listing of the public comments and our responses to them.
The comments covered many topics. There are two major topics that are repeated in different ways.First: Are the data adequate to support the conclusions that we reached? Second: What is the impactif an individual is receiving exposure from multiple contaminants at the same time? Both questionsunderlie the public health determination that we made.
Our brief response to the first question is that we have adequate data to address most potentialpathways. We recommend that more soil sampling be performed to better characterize the areaaround the site. The soil sampling which has been done appears to focus on the areas off site that arepotentially the most contaminated. Using these data, we made a health determination; however, to beassured that there is not off-site soil contamination in areas not predicted, a better off-sitecharacterization should be performed. We also concluded that groundwater exposure to vinylchloride (a degradation product of TCE) was an indeterminate public health hazard for past andpotential future exposures, since, in most cases, the detection limits in the analyses were above ourhealth-based comparison values. During our review of over 800,000 data results and multiplewritten reports, we compared results from DOE, the DOE Investigative Teams, the KentuckyRadiation Control Program, the Kentucky Department for Environmental Protection, the U.S. ArmyCorp of Engineers, and other organizations to make this determination.
For the second question, ATSDR considered interactive (cumulative, additive, synergistic, andantagonistic) effects of substances following exposure to multiple substances to the extent ofscientific knowledge in this area. Cumulative effects (the effects associated with concurrentexposures by all relevant pathways and routes of exposure to a group of substances that share acommon mechanism of toxicity) are addressed on pages 91 and 92 and in Table 24 of the publichealth assessment (PHA). Additive effects (the combined effects of two substances equal to the sumof the effects of each substance given alone) are considered for exposure to radioactive substances.For radioactive materials, potential adverse health effects to critical organs are considered fromexposure to each radionuclide (or multiple radionuclides if the critical organs are the same), and thepotential for adverse health effects to the whole body are considered from total radiation doses to off-site individuals from exposure to all radioactive materials. We know that some substances actsynergistically (when the combined effect of two substances is much greater than the sum of theeffect of each substance given alone), such as those associated with cigarette smoke and radon orasbestos. The interaction of some contaminants is antagonistic (when two substances interfere witheach other's actions or one substance interferes with the action of the other substance), such asconcurrent exposure to selenium and several metals including arsenic, cadmium, and mercury, orconcurrent exposure to nickel and magnesium or zinc. These interactions are considered in thepublic health implications section of the PHA.
At ATSDR, we bring together the collective education and experience of public health scientists,health physicists, toxicologists, epidemiologists, environmental health scientists, physicians, andothers, in the assessment process. In this environment, we keep abreast of current scientific andsocial issues and discuss, both internally and externally, different approaches to the assessmentprocess. As described in greater detail at the end of this appendix, this PHA was peer reviewedoutside ATSDR during the public comment period. Nevertheless, we recognize that not all peoplewill interpret the information the same way we did, and we respect others who may have opinionsdifferent from ours.
The comments received are addressed in the following section. Please note that we used the term"concern" previously in the document to refer to questions and statements collected during ourinformation gathering process. In this appendix we use the term "comment" for questions andstatements about the Paducah Gaseous Diffusion Plant (USDOE) Public Health Assessment, PublicComment Release (March 30, 2001). Statements received which did not concern this PHA or thePHA process and require no response are not included.
The comments are stated as received. Some comments contain page numbers that refer to the publiccomment release and not to the final document. The comments are printed in bold type with ATSDRresponses after each comment or group of comments. (Some of the comments are very similar;therefore, only one response is provided after the grouping.)
PGDP PHA'S QUESTIONS AND COMMENTS RECEIVED BY MAIL DURING AND AFTERTHE COMMENT PERIOD
- The document is well written and contains a great amount of information in atechnical sense about the activities and areas surrounding the plant. Theconclusions drawn appear to be well founded and supported by references tofindings and regulations.
- I am pleased that your assessment found that the plant poses no apparentpublic health hazard for the surrounding community and found no evidencethat previous operations caused any health effects on the neighbors. However,when such findings, no matter how well based on facts and science, contradictthe beliefs of ill people, the findings will be disputed. This is especially truewhen the local newspaper's headlines intimate hazards where none exist.
Response: Thank you.
Response: We acknowledge this comment.
- To the technical reader the report is quite understandable, but to the personwho lives in the area and does not have a technical background the report willnot be understood and therefore questioned. I do think that this could beimproved if a comparison table with the chemicals of concern could be crosscompared to other industries. Examples being power plants, chemicalmanufacturing plants, auto manufacturers, coal mines, etc. This data whenshown in comparison would be more understandable. The data concerningradioactive chemicals and compounds should also show a comparison tablewith other plants: Oak Ridge, Portsmouth, Hanford, Savannah River, AlliedSignal in Metropolis, Cameco, etc.
- Plume Crossing the Ohio River: I agree this is a concern. But should not alsopollution from the UF6 manufacturing plant at Metropolis be a concern?Would it not be prudent to do some well testing in that area?
- The Kentucky Ordnance Works (KOW), a superfund site, and the TVA PowerPlant with its fly ash and coal storage are adjacent to PGDP. How can ATSDRseparate out the effects of one without considering all?
Response: The Superfund law (CERCLA) requires that ATSDR conduct a public healthassessment for all sites proposed for EPA's National Priorities List (NPL). This PHAspecially addresses the chemicals and radioactive materials that are being released or havebeen released from PGDP, which was added to the NPL on May 31, 1994. However, theenvironmental sampling data evaluated in this PHA will necessarily include contaminantsfrom other sources as well as from PGDP. Consequently, the resulting exposure doses basedon environmental sampling data do include exposure from other potential contaminationsources.
- Page EX-2: In the next to last paragraph a statement that the accident wouldhave to generate heat should be included for the paragraph to be credible.
- Page 85: The concern for a major release of material from the depletedcylinder storage yards without a heat source is overstated. There have beenseveral occurrences of cylinders developing openings while in storage with nonoticeable or little impact. Refer to Portsmouth Plant cylinder yard inspectionfindings.
Response: If the leak is small, crystals of UO2F2 will form to seal the opening and prevent orminimize the release of HF. Theoretically, if a large crack breaches the containment in amoist environment, the reaction of UF6 with moisture in the air would produce a white fogconsisting of UO2F2, HF, and heat. The heat and continued interaction of moisture with theUF6 will result in a continuous airborne release. However, this was not the situation duringan incident at Portsmouth Gaseous Diffusion Plant in 1978, when a cylinder containingliquid depleted UF6 was dropped and cracked open. Because of cold weather the UF6dispersion was limited and the reaction with moisture in the air was slow. No one wasinjured, and no off-site hazard existed. Once the cylinders are cooled, most of the UF6becomes a solid. If the UF6 was solid during the Portsmouth incident, the release would havebeen much slower. Heat generated by an external source (e.g., fire) would make the situationmuch worse, increasing the likelihood that the UF6 would be in a liquid or gaseous statereacting much more quickly. If there was significant physical damage to one or more of thedepleted uranium cylinders during transportation or on-site storage and the incident includeda fire, then an off-site temporary public health hazard could exist from exposure to hydrogen fluoride. We have included clarifying statements in the PHA.
- Page 1: The UF6 is heated to form a gas rather than a compressed gas would be more correct. The gas becomes compressed due to the increasing temperature. Thecompression of the gas is related to the compressors used in the process.
Response: This correction has been made in the document.
- Page 1: Large quantities of water are also involved and its final disposal is a concern in the document.
Response: This addition has been made in the document.
- Page 1: It is true that TVA and EEI Joppa were built to supply power but today the power may come from a wide area using the power grid associated with plantsmentioned.
Response: This addition has been made in the document.
- Page 1(last paragraph): There are 6 main process buildings. (This includes C-310 & C-315).
Response: The number of process buildings has been corrected on page 1.
- Page 3: Why is C-331 not cross-hatched? Why is C-315 not shown?
Response: This figure has been removed from the document.
- Page 4: The plant also became fully operational in 1954.
Response: This addition has been made in the document.
- Page 4: In the bottom highlighted item, change metals to metal.
Response: This change has been made.
- Page 73 (paragraph 2): It may be prudent to mention the past use of the areaby the Kentucky Ordnance Works as a source of Hg (mercury). I don't knowif this is the case or not.
Response: The main contaminants from the Kentucky Ordnance Works (KOW) aretrinitrotoluene, toluene, sulfates, metals, nitrates, ammonia, chlorine, nitroaromatics,acids, and hydrocarbons. The U.S. Army Corps of Engineers found elevated levels ofmercury in Ponds 1 & 2, the East Acid Area, and the West Gravel Pit Area of theKOW. The source of the mercury was not identified.
- Page 9, last paragraph: What was the source of the mercury discovered in theponds? What was the source(s) of the mercury and PCBs in Metropolis Lake?
Response: The source of the mercury in the WKWMA ponds is unknown. The source of the mercury and PCBs in Metropolis Lake is unknown. For further information on this subject, contact the Kentucky Department of Fish and Wildlife Resources or the Kentucky Department for Environmental Protection.
- What was the highest environmental concentration of mercury detected off-site? Where is the site location?
Response: The highest concentration of mercury found off site was in a fish samplefrom the Gravel Pit Pond (9.2 ppm) on the former Kentucky Ordnance Worksproperty. The average of the maximums for each type of fish sampled in the PGDParea was 0.45 ppm. The reviewed data included results from DOE and theircontractors, the Kentucky Department for Environmental Protection, and theKentucky Department of Fish and Wildlife Resources. For more information refer tothe Environmental Contamination, Exposure Pathways, and Potentially Exposed Populations section.
- Page 87: Some statement here should be tempered. The release of a liquidfrom an accumulator is one of the major credible accidents determined for aGDP. The only worse case scenario with more impact would be a liquidcylinder rupture outside a building. This type accident has happened on twooccasions that I know of, one at Kerr McGee and one at Portsmouth. In bothcases approximately 2/3s of the UF6 was released due to the cooling effect ofthe UF6 vaporizing. The point being that the total contents of a rupturedcontainer will not be released. I am not saying this to reduce the impact of arupture since a major event would and has occurred.
- Page 86 (bottom) and page 87 (top): This section makes reference to liquidUF6 accumulators used by USEC as part of the ongoing production process.There is not a relationship between the storage of solid UF6 tails cylinders andthese liquid UF6 accumulators. This should not be included in a discussionabout Storage of Depleted Uranium Cylinders.
Response: We agree that the liquid UF6 accumulators should not be discussed under the topic of Storage of Depleted Uranium Cylinders. The earthquake discussion has been modified.
- Page 90: The suggestion to transfer the UF6 from old storage cylinders to new onesshould be reconsidered. This is another potential liquidification step which has somedanger involved. I would suggest concentrating on the overpack issue. In the pastDOE has asked the DOT for permission for one time shipment of the thin wallcylinders - this should be discouraged in the future. No event has occurred with thesethin wall cylinders on over the road movements and in fact the first cylinders used ona routine basis by the Allied Plant in Metropolis were thin walled and passed rigoroustesting. It should be mentioned that there are also a few special cylinders which arenot certified but contain depleted UF6. Special handling of these cylinders will berequired, they will in all probability fail if the contents are liquified.
Response: We agree with these comments and clarified our recommendation on this page.
- The cylinder release in the C-333 building is mentioned many times. The referenceused maximizes the impact but in fact this occurred near the center of the building.The building ventilation system was placed on emergency to maximize air changeswhich would have directed the release to 12 individual exhaust stacks around thebuilding. Most of the released material was drawn through the process motors whichtrapped a lot of the particulate forms so the bottom line is that the impact on theenvironment was probably much less than indicated or implied, maybe by orders ofmagnitude.
Response: ATSDR's evaluation of this accidental release used the NRC RASCAL 3.0 airdispersion model. This model includes explicit reference to the C-333 building and assumesthat the release occurs via the building ventilation. The accident reports also state that 38%of the released material was retained within the building. Consequently our release scenario (Table F-1) assumes only 62% of the UF6 was released from the building.
- The steel used to manufacture cylinders was changed from 285 grade to 516 grade inthe 70 or 80 time frame. The first 516 steel exhibited laminar failure due to includedsulfur so the steel had to be changed to a low sulfur. Some of these high sulfur steelcylinders may be at ORGDP.
Response: Yes, these statements are correct. Precautions will need to be taken with all the old cylinders; in particular, those cylinders made with higher sulfur-content 516 steel.
- Page 45 (top): The report indicates that the C-726 sandblast facility was notupgraded. A dust collection and filter system was installed following a citation by theKDAQ. The facility has been used since this time, but infrequently.
Response: This correction has been made to the report.
- Page 85 (top): The third sentence indicates the number of UF6 tails cylinders storedonsite at Paducah. I checked with the USEC cylinder manager and, as of 5-1-01,USEC has 7,285 cylinders stored at Paducah as compared to the 12,000 in the report.The number of DOE cylinders would need to be checked with DOE or BechtelJacobs.
Response: The number of cylinders in the report included 28,351 generated by DOE andabout 12,000 generated by USEC. However, these numbers change. In May and June 1998,DOE assumed management responsibility for approximately 11,400 cylinders generated byUSEC. According to this comment, USEC had responsibility for 7,285 cylinders on May 1,2001. As of September 25, 2001, DOE indicated that they were responsible for 37,826cylinders. These numbers were used in the report to give the reader an idea of the magnitudeof the depleted uranium cylinder program at PGDP. The wording in this paragraph has beenchanged to reflect the changing nature of these numbers.
- I take exception to the conclusions cited in paragraphs five and six on page EX-2 ofthe Executive Summary. These paragraphs describe the consequences of variousevents, including transportation accidents, fires, plane crashes, severe weather ornatural disasters, and conclude that "It is very unlikely that such accident(s) willhappen". Several events that would lead to very serious and extensive releases of HF(hydrogen fluoride gas) have never been adequately addressed in the various DOEreports during the past four or five years....
The course of action that would responsibly address these concerns would be to beginthe much delayed initiation of efforts to convert the DUF6 into a stable form. Tominimize the HF risk as portrayed in the ATSDR report only gives support to thosein responsible positions who believe that the degraded, rusty cylinders are not asafety concern and plan to begin the conversion in about ten years and complete theconversion in forty or fifty years.
Response: We agree with the above concerns. Even the most unexpected incidents canhappen. Should a major accident occur at the site, we would expect fatalities on site andsignificant injuries off site. The earthquake section of the report, which has been rewritten,addresses one of the concerns more thoroughly. DOE had announced that a contract torecycle the depleted uranium hexafluoride at PGDP would be awarded on January 15, 2002;however, there has been a delay in the announcement. There also will be a delay before the facilities are constructed and the cylinder inventory reduced.
- Page EX-2, line 8: For clarity, change "low enough" to "sensitive enough."
Response: We agree, and this change has been made in the assessment.
- Page 38, line 18: The PGDP Steam Plant does not generate electricity. Itsupplies industrial steam.
- Pages 38 and 41 of the report are incorrect, as the PGDP plant coal firedboilers do not generate electricity as stated in the report. The plant onlygenerates steam for process operations and heating.
Response: We have made these changes in the document.
- Pages 47 and 52: The calculated dose of 340 mrem/year for 1956 appears high. TheCAP88 assessment package must use the maximum of each contributing factor. Itdoes not allow for the buoyancy provided by the plant heat. While most of the 2000megawatt heat load is dissipated by the cooling towers, a significant fraction heats theair on the plant site and affects the micrometeorology of the site. I think somecomment should be included to indicate that the 340 mrem/yr probably overestimatesthe maximum exposure because of this buoyancy effect.
Response: Assumptions used to model past off-site exposures to a "maximally exposedindividual" are very conservative for several reasons as discussed on pages 44 and 45. Thedose estimate of 340 mrem/yr may be an overestimate for several reasons, and a few of thesereasons are discussed in the PHA. However, the buoyancy created by a plant-wide heatingeffect of a few degrees Centigrade is unlikely to significantly affect off-site dispersion ofPGDP air releases and may actually decrease dispersion due to plume rise. Plume rise whichaffects overall dispersion is based on the temperature differential between the stack releaseand the ambient air. An increase in the ambient air temperature will reduce the temperature differential and could lead to decreased plume rise.
- Page 89, 4th paragraph: Uranyl fluoride in air is a particulate aerosol. As aparticulate, concentration values should not be expressed as "ppm." (Does it meanmg/kg? Certainly not vol/vol.) Also in assessing uranyl fluoride exposures, reference(108) is used. Apparently this is a review report, not experimental data. Referenceslike (160) should have been used. Experimentally and epidemiologically they are"doses at which no adverse effects were seen." In the last sentence of the paragraph,the words "It is unlikely that" are not needed.
Response: In the PHA, air concentrations were reported in terms of parts per million of asubstance in air by volume (ppm). Air concentrations can be converted in terms ofmilligrams of a substance per cubic meter of air (mg/m3). The conversion is based on 760 torr barometric pressure at 25 C, and where 24.45 equals the molar volume of air in liters.
The reference used in the cited paragraph and the following paragraph has been changed totwo references written by the researchers. The commentor appears to have misquoted the lastsentence of this paragraph. It reads "It is likely that exposure to uranyl fluoride during an accident will occur over a shorter (acute) duration."
- I thought the ATSDR Assessment for Paducah fell short of it's goal....Ithought it had a lot of good information in it, but the information fell short inmany cases. For instance I would have liked to have seen more information ofthe accidental releases in 1960, 1963, 1969 and two in 1970.
Response: There are specific references to these releases in Appendices E and F. Evaluation of the larger releases in 1960 and 1962 indicates that the smaller releases such as those in 1969 and 1970 would not cause adverse health effects off site. It is unclear what additional information the commentor would like to have for these accidental releases.
- I also would like to have seen a lot more information on the 20 dead deerfound dead in the ditch.
Response: Community members reported that 20 deer were found dead in a ditch;however, no details were given, and no written reports concerning this incident werefound. If more information becomes available, we will evaluate the situation and anyimpact it may have had on the neighboring community.
- ...there is a lot of contamination in this neighborhood. All I want you to do is just keep your research going. Don't give up on us. We need your help.
Response: We are continuing to review information as it becomes available and will reviseor append the conclusions of this assessment if necessary. Also, we will continue to beinvolved with the community through health education efforts and as a resource forinformation, if the community desires.
- I take issue with the finding that there are no current health threats from the PGDP.In September 2000, the DOE held a public meeting in which it was revealed that thereis off-site contamination of plutonium in soils and sediments surrounding the plant.When it was determined that a hit of plutonium was present on his property, agentleman from the audience stood up and asked DOE if the level of plutonium on hisproperty was instead found at the PGDP, whether the area would be roped off as ahealth threat. The DOE officials responded that an area with that concentration ofplutonium would indeed be roped off at the plant. How can plutonium that would be ahealth threat to workers based on a potential eight-hour per day exposure time not bea health threat based on a 24-hour per day exposure time?
Response: We have specifically evaluated exposure doses and potential health effects fromall available plutonium data including those data presented at the September 2000 publicmeeting. The results are included in this PHA.
- By the way, the ATSDR report says that the highest off-site concentration ofplutonium in soils or sediments is 31 pCi/g while the documents released by the DOEat the September 2000 meeting revealed that the highest concentration in soils orsediments was 33.4 pCi/g.
Response: The maximum plutonium 239 concentrations listed in Table 14B of the PHA are31 pCi/g for soil and 53 pCi/g for sediment. Both of these values were used in our exposure estimates.
- The ATSDR report also cavalierly and unscientifically states that off-site plutoniumand other transuranics do not pose a public health threat because they comprise lessthan 10% of the potential off-site releases (pg. 119). Where's the science behind thatstatement?
Response: The commentor misquoted the statement from our document. ATSDR's PublicHealth Assessment states on page 117 (formerly page 119), "Other radioactive contaminants(e.g., thorium 230, plutonium 239, neptunium 237)...contributed approximately 10% or lessto the exposure doses." "Exposure doses" and "potential off-site releases" are not the same.Releases are reported in total quantity (curies or becquerels) or in concentrations (e.g., curiesper liter or becquerels per kilogram). The releases of plutonium and other transuranics arereported in the "Environmental Contamination, Exposure Pathways, and PotentiallyExposed Populations" section of the report and are much less than 10% of the release ofuranium and technetium 99. Refer to the technical experts review comments at the end ofthis appendix in response to the question concerning the scientific basis of our report.
- Also, incredulously, the ATSDR acts throughout the entire document as if a mrem ofexposure from transuranics is equivalent to a mrem of exposure from uranium ortechnetium 99. Interesting? That cuts against everything I have ever heard abouthealth threats from transuranics.
Response: A millirem (mrem) is numerically equal to the absorbed dose in milliradsmultiplied by a quality factor (a linear-energy-transfer-dependent factor). A millirad is equalto 0.1 ergs of energy absorbed per gram of material (or 0.00001 joules per kilogram). Amillirem from exposure to a transuranic produces equivalent biological damage as amillirem from exposure from other radioactive materials. A millisievert is equal to 100 millirem; both are units used to describe the amount of energy absorbed by material.
For each radioactive material the quantity (millicuries or becquerels) required to produce a millirem (or a millisievert) and how the substance behaves in the body are different.
- The ATSDR does acknowledge that data gaps from 1969 and 1970 reveal that it islikely that more radioactivity was released to the atmosphere from the plant thanmonitoring data suggest, yet the agency does not even try to correlate that withreports that houses were blackened and trees were killed during that time period(pgs. E3-4). It is reasonable, given the acknowledged data gaps, that nearby residentsare neither lying or exaggerating when they speak of the effects of the releases fromthe PGDP during this time period, and some effort should be made to correlate whattype, concentration, and amount of emissions would have had to have occurred inorder to blacked houses and kill trees and what the health effects from such a releasewould have been or still might be. Without quantifying or qualitatively stating whatthe health effects might have been from release(s) able to blacken houses and killtrees, the ATSDR reaches the shocking conclusion that no emissions from the plantcould have resulted in birth defects, mental retardation, or cancer clusters (pgs. 144-5).
Response: ATSDR reviewed incident reports, release information, air monitoring data, andother environmental sampling data for the time period mentioned. As stated on pages E-3and E-4, weekly air monitoring data indicated that there were periods of elevated grossalpha and gross beta during 1969 and 1970, but there was no explanation of the cause(from incident or release reports). When air monitoring data in different directions from theplant were elevated above the normal pattern, a search was done to see if there was acorrelation with any reported incident and any other sampling data. For the 1969 and 1970period, there was no incident report and no monitoring data that would have suggested alarge enough release to blacken houses or kill trees. The house in question was more than amile from the site. If the house was blackened and the trees were killed by a release from theplant, other houses and trees between this location and the plant would have experienced thesame or worse conditions, but no other reports were received. After extensive review ofmonitoring and release data, we could not identify a release from PGDP that would havecaused this effect.
- Moreover, the agency misleadingly states that there are no reports to indicatewhether residents near the PGDP have suffered adverse health effects from the plant(pg. 144). How come no mention is made of the EPA-commissioned report done by(name redacted) of Tri-State Consulting that documents adverse health effects inthese neighborhoods? While the (name redacted) report is not an epidemiologicalstudy, certainly the data merits some attention by the ATSDR.
Response: On page 142 (formerly page 144), the report states "the areas for which cancerstatistics are gathered are too large to let us pinpoint any specific neighborhood". On page130 (formerly page 132), it states "ATSDR representatives also reviewed informationcollected in January 2000 by Tri-State Consulting of Independence, Kentucky...."
- Also ignored by the ATSDR are the potential lasting effects from the presumedreleases in 1969/1970. Children, infants, toddlers, and those still in their mothers'wombs are now of child rearing age. It is erroneous to state that these peoples'offspring are free of risk when you acknowledge that you do not know how muchexposure occurred in 1969/1970.
Response: One of our conclusions is that past accidental airborne releases of uraniumhexafluoride and the resulting exposures are indeteriminate, because total release quantitiesand completed exposure pathways during these incidences are uncertain. However, we havenot seen data that would suggest that there was a large release of chemicals and/orradioactive materials in 1969/1970. Radiation exposure that causes birth defects and mentalretardation must be much higher than the potential off-site exposures near PGDP. Theexpected adverse health effects from a large uranium hexafluoride release would beprimarily respiratory problems from the hydrogen fluoride gas with an increase in the risk of lung cancer and nephrotoxicity (kidney problems) from the uranyl fluoride.
- I also find fault with some of the terminology used in the report. The reportextensively uses MCLs to gauge whether there is a public threat from contaminatedgroundwater; however, as you undoubtedly know, MCLs take into considerationeconomic considerations and are thus not truly health-based criteria. It is much moretruthful to gauge health risks by comparing contamination levels to actual orproposed MCLGs, where they exist. Even though MCLGs are not enforceable bygovernmental agencies, they, nonetheless, are EPA's best guesstimate on what are"safe" levels of chemicals like TCE and PCBs in drinking water.
Response: Appendix C of the Public Health Assessment describes health guidelines,comparison values, and exposure factors. On page C-2 we state that MCLs are regulatorystandards set as close to health goals as is feasible and are based on treatment technologies,costs, and other factors. We normally do not use MCLs; however, they were used as ascreening level for sulfate, sulfide, thallium, bis(2-ethylhexyl)phthalate,bromodichloromethane, and trichloroethylene (TCE). Please refer to the Public HealthImplications section of this document for discussions regarding thallium, TCE, and PCBs.
- The ATSDR report also occasionally throws out undefined or exceedingly ill-definedterms and acronyms such as "action levels" and "Chr. EMEGcs." I am reasonablywell informed on the terminology associated with these issues and I know of two typesof action levels used by the EPA - drinking water and body level - yet the report doesnot identify what actions levels are being referenced. Moreover, I have never evenseen the acronym "Chr. EMEGc" before. Terms used in the report should be definedand explained why they are of value in the report.
Response: In the PHA, the term "action level" has been used to refer to several action levels.EPA's drinking water action level for lead is used in Table 3 and on page 25. The "actionlevel" of 10 µg/dL of lead in blood is the related to adverse health effects in children. (Seethe discussion of lead in the Public Health Implications section of the document.) We haveadded clarification or references for these terms. The U.S. Nuclear Regulatory Commissionaction level for response during an emergency was also used when discussing accidentalreleases of UF6 and was explained in parentheses. EPA's action level for radon in homes was also used in the discussion of radon gas and was referenced in the document.
The key to Table 3 defines Chr.EMEGc as a Chronic Environmental Media EvaluationGuide for Children. As stated in Appendix C, the Environmental Media Evaluation Guides(EMEGs) are derived from Minimal Risk Levels (MRLs) and apply only to specificdurations of exposure. They also depend upon the amount of contaminant inhaled oringested and thus are determined separately for children and adults, as well as for various durations of exposure.
- ...the report fails to acknowledge that the DOE has not committed, in writing, tocontinue supplying drinking water to residents until their groundwater is deemedsafe. DOE renews its water policy every 5 years and the residents in the area wouldhave little recourse should DOE decide to prematurely pull the plug.
Response: This is correct, and we have clarified this in the report. However, the health of thecommunity will be protected as long as residents continue to use the municipal water.Whether DOE continues to pay for the municipal water service is a separate issue.
- In general, the document uses the dose quantities published in InternationalCommission on Radiological Protection Publication 60 (e.g., committed effectivedose, equivalent dose). Recent DOE publications regarding the Paducah site use thedose quantities (e.g., committed effective dose equivalent, dose equivalent) specifiedin radiation protection requirements published in the United States Code of FederalRegulations (i.e., those published in U.S. Environmental Protection Agency FederalGuidance Report Numbers 11 and 12). To avoid confusion, a discussion of the use ofthe newer quantities and comparison with the regulatory quantities needs to beincluded.
- In the second paragraph, last sentence of the document (note), it implies that therewere no regulations or mandatory standards prior to 1997. We suggest that this berevised to read: Before the plant was privatized, the facility was subject to DOEregulations and standards.
Response: The statement in the second paragraph of Document Note has been modified.
- Table 6: Need to define type of dose listed (e.g., annual committed effective dose).
Response: "Committed effective dose" has been added in Table 6 for U 234 and 238, as well as Table 5 for Tc 99.
- Table 25, footnote 5: For air exposure pathway, it indicates the values are based on1956 concentrations. Page 47 discusses a 1960 accident resulting in the acute doseslisted in the table.
Response: A correction has been made to footnote 5, Table 28 (formerly Table 25) toindicate that 1956 concentrations were used to estimate chronic exposure and 1960accidental release concentration was used to estimate acute exposure.
- Appendix I: Need to define the following terms used in the document or in thedefinition of other terms: equivalent dose, effective dose, and rad.
Response: These definitions have been added.
- Did you explore the cumulative impacts of metals, of chemicals, ofradionuclides, of metals and chemicals, metals and radionuclides, chemicalsand radionuclides, and of chemicals, radionuclides, and metals?
- ... the report glaringly fails to consider cumulative and synergistic effects ofthe different contaminants. Some effort should at least be made to try to gaugewhat are the total effects of the different chemicals present in the areassurrounding the PGDP.
- How can the agency just ignore the fact that potential receptors are receiving multiple contaminants at the same time? What is the impact of that? What are the simultaneous loads which a MEI could receive?
- Given the same dosage, is the health effect(s) of multiple toxicants greaterthan the health effect of a single toxicant?
- Are there possible synergistic effects of the pollutants from these three sites (PGDP, the Kentucky Ordnance Works, and TVA Power Plant)?
- Did you use any "special rules" when reviewing chemicals that have similarhealth effects? Do you believe the limits should be lowered for those types ofchemicals in combination?
- The Paducah Gaseous Diffusion Plant Citizens Advisory (Board) feels theAgency for Toxic Substances and Disease Registry's recent Public HealthAssessment is incomplete. At its May 17, 2001 meeting, board membersacknowledged the difficulty of cumulative analysis, but concurred that thedocument should have considered the cumulative and synergistic effect ofexposure to various chemical and radioactive agents on the health of peopleworking at or living near the facility.
- Is it your contention that the chemicals, metals, and radionuclides that werenot selected as "contaminants of concern," present no adverse health impactat their current levels in the environment?
Response: This public health assessment addresses off-site exposures to radioactive and non-radioactive substances released from PGDP. Other agencies and projects are addressingexposures to people working at the facility.
ATSDR considered interactive (cumulative, additive, synergistic, and antagonistic) effects ofsubstances following exposure to multiple substances to the extent of scientific knowledge inthis area. Cumulative effects (the effects associated with concurrent exposures by all relevantpathways and routes of exposure to a group of substances that share a common mechanismof toxicity) are addressed on pages 91 and 92 and in Table 24 of the PHA. Additive effects(the combined effects of two substances equal to the sum of the effects of each agent givenalone) are considered for exposure to radioactive substances on pages 117 through 119 inthe PHA. For radioactive materials, potential adverse health effects to critical organs areconsidered from exposure to each radionuclide (or multiple radionuclides if the criticalorgans were the same), and the potential for adverse health effects to the whole body areconsidered from total radiation doses to off-site individuals from exposure to all radioactivematerials. We know that some substances act synergistically (when the combined effect oftwo substances is much greater than the sum of the effect of each substance given alone),such as those associated with cigarette smoke and radon or asbestos. The interaction of somecontaminants is antagonistic (when two substances interfere with each other's actions or onesubstance interferes with the action of the other substance), such as concurrent exposure toselenium and several metals including arsenic, cadmium, and mercury, or concurrentexposure to nickel and magnesium or zinc. These interactions are considered in the public health implications section of the PHA.
ATSDR has reviewed the scientific literature surrounding chemical interactions and notedthat if the estimated exposure doses for individual contaminants detected at the site are belowdoses shown to cause adverse effects (No Observed Adverse Effect Level (NOAEL)), thenATSDR considers that the combined effect of multiple chemicals will not result in adversehealth effects. Several animal and human studies [1,2,3,4] have reported thresholds forinteractions. Studies have shown that exposure to a mixture of chemicals is unlikely toproduce adverse health effects as long as components of that mixture are detected at levelsbelow the NOAEL for individual compounds [5,6]. Additionally, the absence of interactionsat doses 10-fold or more below effect thresholds have been demonstrated [7,8]. Specifically,in two separate subacute toxicity studies in rats [9,10], adverse effects disappearedaltogether as the dose was decreased to below the threshold level. For carcinogens, theinteractions are more difficult to quantify at environmental doses because at the lower dosesobserved from environmental exposure a large study group (humans or animals) is neededfor statistical significance. In an animal study, Takayama et al. (1989) reported that 40substances tested in combination at 1/50 of their cancer effect level (CEL) resulted in anincrease in cancer . However, Hasegawa et al. (1994) reported no increase in cancerwhen dosing animals at 1/100 of the CEL for 10 compounds . It should be noted thattypical environmental exposures to chemicals (non-carcinogens and carcinogens) are greater than 1000 times below thresholds.
- The board also would like to request a detailed study be made of the residents ofBradford Road to determine if there is a cluster of cancers known to be caused by orlinked to certain contaminants known to have been released by the PGDP.
Response: During discussions with local citizens early in the health assessment process, wewere made aware of their concerns for the people on Bradford Road. However, ATSDRcannot recommend a detailed health study for the residents of Bradford Road in the PGDPpublic health assessment, since completed exposure pathways do not exist for site relatedchemicals to the citizens living on Bradford Road.
- Finally, it should be noted that there appears to be a higher-than-expected incidenceof bladder cancer among patients at Western Baptist Hospital in Paducah. The boardfeels this should bear additional examination by ATSDR to determine if this isassociated with in any way known or suspected elevated levels of bladder cancers inPGDP workers.
Response: This public health assessment addresses potential off-site exposures to radioactiveand non-radioactive substances released from the Paducah Gaseous Diffusion Plant. It doesnot address on-site exposures of the PGDP workers. The U.S. Department of Health andHuman Services, National Institute for Occupational Safety and Health (NIOSH) isresponsible for researching potential health hazards experienced in the workplace and hasperformed worker studies that included the PGDP employees. For further information aboutthese studies, contact the NIOSH Division of Surveillance, Hazard Evaluations, and FieldStudies in Cincinnati, Ohio at (513) 841-4400.
As stated in the public health assessment, ATSDR evaluated statistical data from theKentucky Cancer Registry using age-adjusted rates for nine general types of cancer from1991 through 1998. The types of cancer included brain/central nervous system, bladder,female breast, Hodgkin's lymphoma, kidney, leukemia, liver, lung, and non-Hodgkin'slymphoma. Bladder cancer in Ballard County may warrant further investigation; however,we are not able to determine any association between the occurrence of bladder cancer inBallard County and exposure to environmental contamination from PGDP.
Following this request by the Citizens' Advisory Board, ATSDR evaluated the age-adjustedtotal cancer and bladder cancer rates from 1991 through 1999 for McCracken and Ballardcounties by comparison to State age-adjusted rates, Purchase Area Development Districtage-adjusted rates, and rates for other counties in Western Kentucky including Calloway,Calisle, Fulton, Graves, Hickman, Livingston, and Marshall. The following table gives theresults:
|State or Area in State||All Cancers||Bladder Cancer|
|Commonwealth of Kentucky||413.76||15.56|
|Purchase Area Development District||406.73||15.42|
|1Kentucky Cancer Registry's website http://web.kcr.uky.edu|
Based on this additional information, bladder cancer rates appear elevated in Ballard Countyand in other counties in Western Kentucky that are not affected by releases from PGDP.ATSDR cannot determine the cause of this disease based on existing data. There are anumber of factors (e.g. age, cigarette smoking and industrial exposure to knowncarcinogens) that have been shown to be related to the incidence of bladder cancer. Onepossible explanation for the higher than expected number of cases in the area may be thelarge percentage of persons 65 years of age and older. (Refer to Appendix A in the PHA.)Bladder cancer rarely occurs in people under 40 years of age.
- I have read your Public Health Assessment and it is clear to me this is an attempt to mislead the public about what went on at the plant. It has no basis in fact and assumes things that is not true. It does not address the releases that happened by accident or on purpose. It is part of a desperate attempt to cover up what went on at the plant. It doesn't address the dumping of hazardous material. The whole place is so contaminated that it cannot be cleaned up in a million years. This is called public misinformation. I would be glad to put things straight, but it would take a month's work and volumes of information. I would like to say to those who ran the plant "Have you no shame for what you have done to the people who live and work at the plant? You have made the people who live near the site sick and many have died as a result of what you have done. To do this to innocent people is equal to the holocaust. You have no right to live among descent people."
Response: This public health assessment is a technical review of an enormous volume of data concerning potential contamination, exposure, and health effects. It also specifically addresses comments, concerns, and questions related to PGDP operations and potential contaminant exposure.
- We (name redacted) think that the fact that your report was based upon existing DOE data instead of ATSDR taking its own independent data makes the report useless from the very beginning. In fact, the DOE's ESH investigative team found numerous problems with the DOE's data when they investigated the site after the Washington Post story of Aug. 8, 1999 ran disclosing that there was significantly more transuranic contamination at the facility than DOE had previously admitted. In the face of these admissions, the ESH team's findings, and the reports that the media has put forth since that time regarding the situation at the plant, we just can't accept the skewed conclusions of the ATSDR that the plant is 4th on a list of 5 levels of risk to the public.
Response: ATSDR did not use only DOE data. During our review, we compared results from DOE, DOE's ESH Investigative Teams, the Kentucky Radiation Control Program, the Kentucky Department for Environmental Protection, the U.S. Army Corps of Engineers, and other organizations. DOE's ESH Investigative Teams for the Phase I and Phase II independent investigative reports found various deficiencies in the historical and current radiological protection program; however, their conclusions did not find "numerous problems with the DOE's data." ATSDR found problems with some aspects of the environmental sampling data as noted in the PHA; however, the data available provided an adequate basis for the public health conclusions.
- First off, the agency uses a contaminant by contaminant analysis to try and determine any risks. It conveniently finds that for each contaminant, while there are detectable levels off site, that each is somehow below an action level. But, DOE has released contamination maps of areas on and off the site based upon the figures in the Phase I and Phase II site studies, and these maps show such things as soil contamination of plutonium some 40 times greater than background on private property off the site. At the same time, neptunium, uranium, technetium, thorium, and other contaminants are also found at significantly above background levels in the same locales.
Response: The concentrations and assumptions used for our potential dose estimates are described in the Environmental Contamination, Exposure Pathways, and Potentially Exposed Populations section. A description of our health guidelines, comparison values, and exposure factors can be found in Appendix C. When a concentration of a chemical or radioactive material exceeds background levels, it does not mean that the concentration will or will not cause adverse health effects. The potential dose, whether from background concentrations or above, determines the potential health effect. We used a total potential dose from all radioactive materials without subtracting background values.
- In addition, organic contaminants have been found offsite also, and some of them, such as PCBs are persistent and highly toxic.
Response: Organic compounds were evaluated in this PHA; however, they were not at a level off site to cause adverse health effects. The concentrations and the assumptions we used for ingestion of PCBs, etc. are described in the Environmental Contamination, Exposure Pathways, and Potentially Exposed Populations section of the PHA.
- Did you look at dioxin?
There is also significant dioxin contamination on site, and that isn't even addressed at all by the study.
Response: As stated in the Document Note, this PHA addresses potential off-site exposures to radioactive and non-radioactive substances. Dioxin has been found on site. ATSDR evaluated potential off-site dioxin exposures and determined that it was not a contaminant of concern.
- The big flaw in the agency's analysis is that it doesn't properly take into account past releases, and, how long the half-lives for many of these contaminants. For example, many curies of Tc99 were released into the environment. This chemical has a half life of many, many thousands of years. Therefore, any of it released within the last 40 years is still there at almost full strength. The same is true of the other persistent chemicals and radionuclides released at the site. It isn't like they are going anywhere. Yet this isn't addressed at all in the document.
Response: The PHA addresses Tc 99 released to the environment (past and present) in theEnvironmental Contamination, Exposure Pathways, and Potentially Exposed Populationsection. The statement that any of the Tc 99 released in the past 40 years is still there iserroneous. Although Tc 99 has a long half-life, it is very mobile in the environment. Eachchemical and radionuclide behaves in the environment differently, which was taken intoconsideration in our evaluation.
- Every place that there has been samples taken to document bioaccumulation ofcontaminants in various life forms around the plant, they have been detected?
Response: Bioaccumulation is more than the detection of a substance in a biologicalspecimen. Bioaccumulation is the increase in concentration of a contaminant from theenvironment to the first organism in the food chain. Biomagnification is the increase inconcentration of a contaminant from one link in a food chain to another. In order forbiomagnification to occur, the contaminant must be long-lived, mobile, soluble in fats but not in water, and biologically active.
Biota samples were collected from areas in all directions from the site with the largestpercentage collected northeast, north and northwest of the PGDP site. Not all samplesshowed bioaccumulation or biomagnification of potential contaminants. For example, lessthan 10% of the crop sample analyses detected Tc 99. The concentrations of potentialcontaminants used in the ATSDR public health assessment to determine potential exposureswere maximum values or average of the maximum values for the type of biota.
- What is the average body burden of uranium, technetium, plutonium, lead,etc. in the residents around the facility? How can you establish any kind ofbaseline if this information isn't included in the analysis?
- Did you ever quantify the actual dose any resident received of any metal,chemical, or radionuclide?
Response: A public health assessment is an evaluation of relevant environmental data, healthoutcome data, and community concerns associated with a site where hazardous substanceshave been released. The health assessment identifies populations living or working near thesite for which more extensive public health actions or studies may be needed. Estimatedexposures and radiation doses were calculated for the hypothetical maximally exposedindividuals. Refer to the section "Environmental Contamination, Exposure Pathways, andPotentially Exposed Populations" for estimated values and assumptions used in ourevaluation.
- We think that a more detailed study of the distribution and effects of Chromium 6contamination of the area. For decades chrome 6 went out the cooling towers. Thestudy says that it was only distributed 1500 feet, but there is no credible sciencebacking this up, and it defies common sense. What studies have been done todocument whether or not this is true? Chrome 6 is the contaminant in the famousErin Brockovich movie, one which is very toxic and which the citizens in the moviereceived a settlement for contamination of their groundwater by the substance. If it isthat bad, then shouldn't a little extra effort be made to find out where it has dispersedto and whether its having any impact. Instead, the agency is relying on unreliable datato make generalized conclusions, and this is the big flaw with the document.
Response: The distribution of hexavalent chromium was evaluated using the EPA IndustrialSource Complex air dispersion model and measured distribution of hexavalent chromium insoil samples. The measured distributions are consistent with the estimated concentrationsfrom the model and provide an adequate basis for the public health conclusions. We alsoevaluated chromium (in particular, hexavalent chromium) in surface water andgroundwater. Refer to the Environmental Contamination, Exposure Pathways, andPotentially Exposed Population section and the articles referenced in the PHA. Also, refer toour discussions of chromium in Appendix H, the Public Health Implication section underSpecific Substances, and ATSDR's Toxicological Profile for Chromium which is acompilation of the results from many animal and human studies.
- The agency stated at the public meeting that it was safe to consume vegetables withdetectable levels of Technetium in them. I asked at the meeting for documentation ofthis, and the agency agreed to provide it, but hasn't. Therefore, I repeat my requestfor any and all scientific documentation that proves or supports the assertion that itis safe to eat vegetables containing detectable levels of technetium 99.
Response: This information has been sent to this commentor.
- Your main authority at the public meeting, Mark Evans, is not an epidemiologist. Infact, according to news accounts, he is a geologist. How can he have any expertopinions on the toxicology effects of the contaminants on the people in the region.
Response: Dr. Mark Evans is an environmental geologist. The person who talked at thepublic meeting about toxicologic effects of contaminants was Dr. Karl Markiewicz, who is a senior toxicologist with ATSDR.
- The fact that the agency took so many years to complete the draft also detracts fromthe credibility of the agency. It appears that the delay was political in nature, and,when added to lack of credibility of the key findings, i.e., that there is nothing toworry about in terms of the exposures to contamination from the facility, is nothingmore than a convenient agency position to help DOE and the corporate contractorsto escape responsibility for their careless handling of these very toxic substances.This is not what Congress intended when they created the agency. Your mission is toprotect the public from such hazards, not make it easier for them to be or continue tobe exposed.
Response: ATSDR's mission is to provide a science-based public health evaluation of thepotential community exposure and health effects at hazardous waste sites. The public healthconclusions in this document are well supported by scientific knowledge of hazardoussubstance exposures and health effects. ATSDR reviewed approximately 800,000 samplingdata points and hundreds of documents and research papers, used several methods to gathercommunity concerns, and researched databases for past and present information on PGDPand related topics.
- We support at a bare minimum the recommendations of the PGDP SSAB, but reallybelieve that a full blown Health Study is both wise and required. We also believe thisshould be based upon independent, current, in the field sampling and studies and notjust a rehash of unreliable data. We urge you to relook at this situation and rethinkthe finding that no further health studies are necessary.
Response: This evaluation of potential off-site contamination does not indicate potential exposures capable of producing adverse health effects.
- Did you detect deficiencies in groundwater sampling procedures from 1990through 2000? If so, briefly discuss those deficiencies.
- Did you detect deficiencies in air sampling data from 1990 through 2000? Ifso, briefly discuss those deficiencies.
- Did you detect deficiencies in soil sampling data from 1990 through 2000? Ifso, briefly discuss those deficiencies.
Response: Deficiencies in environmental data are noted in each applicable section of the PHA.
- Page 156 - #4: Was any business within 4 km of PGDP using contaminated wellwater? Has DOE provided an alternate source of water to any business(es)?
Response: No businesses used contaminated well water above health-based comparisonvalues. However, there are some businesses within the Water Policy Area who have beenprovided with an alternate source of water.
- Page 156 - #8: Are you referring to new monitoring wells, previously sampled wells, or a combination of both?
Response: Any of the above that could adequately be used to determine possible migration ofcontaminants from the RGA to the McNairy Aquifer as long as they do not create a conduitfor vertical migration.
- Was waste oil from transformers and capacitors land farmed? If so, how manygallons?
Response: Yes, waste oil was land farmed on the southwest corner of the site. (Refer to Table 1 in the PHA.) At least 5,000 gallons of waste oil were applied.
- How close is the nearest residential well to the former PGDP oil land farm?
Response: The C-747-C oil land farm is approximately 2000 meters from the nearest residential well.
- Were residential wells sampled for Iodine 131 and/or Iodine 129?
Response: Iodine 131 (I 131) and iodine 129 (I 129) are beta emitters. Although residentialwells were not specifically analyzed for I 131 or I 129, they have been analyzed for betaemitting radionuclides. We reviewed the KRCP's residential well sampling data fromJanuary 1, 1989 through June 30, 1999. All residential well samples were analyzed for betaemitters and technetium 99 as well as other radionuclides. The four wells with elevated beta emitting materials were elevated due to technetium 99.
- Page 156 - #4: As part of DOE Water Policy (1993-94) $380,929 was spent on capping and locking residential wells.
Response: Capping and locking residential wells do not always prevent future use. Werecommend disconnecting water pipes to the home or business and plugging or dismantlingthe wells.
- Page 156, Recommendation Number 5: "Encourage residents who are concernedabout lead in their drinking water to have their water tested. (Lead did not appear tobe related to groundwater plumes.)" Based on current groundwatercharacterizations and groundwater analytical data, there does not appear to be aconcern with lead emanating from the PGDP in groundwater.
Page 156 - #5: Residents are also concerned about other contaminants in their well water; why did you single out lead?
Response: Sixty-seven off-site samples were analyzed for lead with 16 analyses above ourhealth-based comparison value. The location of these samples did not indicate that the sourceof the lead was from PGDP. Three samples from residential wells no longer in use wereabove the comparison value, but not all residential wells were tested for lead. There arepotentially other sources of lead such as plumbing; however, the problem does not appear tobe widespread. If people are concerned, they should have their water tested for lead or any other potential contaminant that they may be concerned about.
- What was the source of the contamination in the residential wells located in the 1994 Bethel Church Road Extension, DOE Water Policy Area?
Response: There was no contamination originating from PGDP in the residential wells located on the Bethel Church Road Extension of the DOE Water Policy Area.
- Page EX-1: Define "under normal operating conditions".
Response: Anything that is not unexpected and was considered during review of the designand operation of the facility. We have changed the wording on page EX-1 to read "underexisting conditions and normal operations."
- Page 167-169, #65: Did the Annual Environmental Reports listed include calculationsof radiation doses to off-site populations? Did the Annual Environmental Reportsconsistently monitor the same radionuclides?
Response: Release and monitoring information was in these reports, but usually calculationsof radiation doses to off-site populations were not. The annual environmental reports hadinformation on monitoring for uranium or uranium isotopes and usually technetium 99;however, other radionuclides were not included until more recently. For further details, referto the Environmental Contamination, Exposure Pathways, and Potentially ExposedPopulations section.
- Did you review USEC Air Emissions...1997, 1998, 1999, 2000?
Response: No. Since March 3, 1997, USEC has been regulated by the U.S. NuclearRegulatory Commission for the operation of the plant and has been subject to therequirements of 40 CFR 61, Subpart H separate from DOE. This PHA reflects DOE's andits predecessors' activities at this site. The air emissions considered in the air pathway section for 1997 forward were from DOE activities.
- A chromate-zinc-phosphate compound was used as a corrosion inhibitor until 1993; after 1993 what was used as a corrosion inhibitor?
Response: One cooling tower complex was converted to a phosphate-based corrosioninhibitor (with no chromium) in 1992. The others were converted to the new corrosioninhibitor in 1993.
- The highest annual quantity of hexavalent chromium was released in 1992. Howmuch was released and into what media? Was more hexavalent chromium released in1992 than was released in 1962 (? As to exact year) when all the water in the coolingtower pits was used to extinguish a fire?
Response: In 1992 the largest amount of airborne hexavalent chromium (2,015 kg) wasreleased. (Refer to Table 8B.) For surface water releases we evaluated the concentrationsof hexavalent chromium (not the total amount released). The highest concentration releasedto Little Bayou Creek occurred in 1959 before a change was made in corrosion control forthe cooling towers. Although the total amount of chromium released may have been higherin 1962, the concentration of hexavalent chromium in surface water releases to Little Bayou Creek were lower probably due to dilution with larger volumes of water.
- Page 44: "Since 1993,..., DOE has not reported process release information or off-site air monitoring data." Since 1993 who has gathered and reported this data?
Response: USEC. For this report, we reviewed USEC's emissions data from 1993 to 1997 aswell as air monitoring data reported by USEC and the Kentucky Radiation Control Program.
- What was the highest concentration of PCBs detected off-site? Where is this site located?
Response: The maximum concentrations of PCBs detected off site are described in theEnvironmental Contamination, Exposure Pathways, and Potentially Exposed Populationssection. Most of these are found near Outfall 011 and Little Bayou Creek.
- Page 7: "US Route 60 (Figure 1)...." Page2: Figure 1 does not identify US Route 60.
Response: We changed the narrative to refer to Hinkleville Road (the old US Route 60).
- Page 139, #6: The Fort Massac Water District wells are in NE Massac County; theiroffice is in Eddyville (Pope County), Illinois. The source of this well water is the Ohioand Cache River Valley Aquifer.
Response: This comment is correct, and the correction has been made.
- Pages 4 and 5: As of this date, is United States Enrichment Corporation agovernment-owned corporation? Is USEC licensed by the U.S. Nuclear RegulatoryCommission?
Response: USEC began operating as a private-sector corporation on July 28, 1998 and islicensed by the U.S. Nuclear Regulatory Commission. A clarification has been added to page 4.
- Page 9, last paragraph: Did you review any U.S. Army Corp of Engineers samplingdata and/or reports from the former Kentucky Ordnance Works remedialinvestigation and cleanup? If so, did you compare that information with remedial andcleanup data gathered for PGDP?
- Page 8, figure 3 [ ] green, DOE property boundary: Are there any PGDP wasteburial sites outside the DOE property boundary? [ ] gold, WKWMA: Are there anyPGDP waste burial sites outside the WKWMA?
Response: If you are referring to permitted waste burial sites, the answer to both questions is"no". If you are referring to waste released from the site, such as the rubble and debrisreleased off site and discussed in documents for the Waste Area Grouping 17, then "yes" to both questions.
- TCE is linked to speech impairments and hearing impairments in children.Were children in the Water Policy Area evaluated for those adverse healthconditions?
- TCE is linked to anemia in adult males and urinary tract disorders in adultfemales. Were adults in the Water Policy Area evaluated for those respectiveadverse health conditions?
Response: Not all children in the Water Policy Area were exposed to elevated levels of TCE.There were four residential wells with elevated concentrations of TCE before the residentswere given an alternative water supply. The individuals (including children) using thesewells were included in a health survey performed by the Occupational Health Clinic,University Occupational Medicine Group of Cincinnati, which included among other tests aphysical exam covering vital signs and heart, lung, abdominal, neurological, skin andlymphatic evaluations. (One family declined.) The survey began in December 1988. Follow-ups were performed until March 1990; however, only three individuals continued with thefollow-ups. No evidence of any disease associated with TCE was found in these individuals.
- Do the vital statistic registries of Western Kentucky include a secondary cause orcontributing cause of death? If a person living in McCracken County, Kentucky isdiagnosed and treated for cancer in another state (IL, MO, TN), would that case be ina registry for McCracken County, a registry in another state, or not recorded at all?
Response: Yes to the first question. No to the second question; the case would be recorded inthe state were it occurred according to that state registry. For further information on vitalstatistic registries in Kentucky, contact the Office of Vital Statistics, 275 East Main Street - 1E-A, Frankfurt, KY 40621, phone (502)564-4212.
- Page 132 - Statistics: What is an "area development district"? What areadevelopment districts are in Western Kentucky?
Response: Kentucky counties are grouped into 15 "area development districts", or ADDs.ADDs are not public bodies established under Kentucky law but are similar to a partnershipof the local government units. The boards of directors are comprised of locally-electedofficials and citizens. Paducah is in the Purchase ADD. For further information contactHenry Hodges, Executive Director, 1002 Medical Drive, Mayfield, KY 42066, phone(270)247-7171.
- Was there any incidence of cylinder leaks or ruptures from 1990 through 2000?
Response: There were no cylinder ruptures, but there were leaks associated with the cylinder connections. None of the releases affected the off-site community.
- Can a gaseous effluent contain suspended, inhaled particulate?
Response: Yes. If a gas is released, it can change chemically in the atmosphere and can staya gas, change to a particulate, or adhere to a particulate in the air. If a person breathes thisair, the particles may or may not be inhaled depending on the particle size.
- Page E-2: "According to our modeling of this accident...." May I have a copy of those calculations?
Response: These calculations were performed using the U.S. Nuclear RegulatoryCommission's (NRC's) RASCAL 3.0, Beta 2 computer program. We can provide the endresults, but if the commentor wants to understand the calculations, he/she will need to obtainthis computer program and the NRC's NUREG-1741, "RASCAL 3.0: Description ofModels and Methods." NRC publications from the NUREG series can be ordered from oneof two sources:
- Page 10: On average, how many times a year does Big Bayou Creek overflow itsbanks into people's fields? Does this occur the entire length of Big Bayou Creek?
Response: The number of times a year and the length of time that Bayou Creek overflows itsbanks vary significantly with the amount of rainfall in the area and flooding of the OhioRiver. The average annual rainfall for this area is 44 to 48 inches with the heaviest rains inthe winter and spring; however, there was a 10-inch rainfall deficit in 1999 and a majorflood in 1997. The overflow does not normally occur the entire length of the creek.
- Elevated cancer rates are NOT the only health concern in the communitysurrounding PGDP.
Response: We agree. However, the largest group of concerns were about a variety ofcancers. In Appendix B, we also discuss concerns about non-cancer effects, environmentalexposures, and procedural concerns.
- Are PCBs linked to brain cancer?
Response: One study by Loomis et al  reported that electric utility workers exposed toPCBs had significantly increased mortality from malignant melanoma and brain cancer.However, a more recent study by Kimbrough et al  reported no excess cancers of theliver or any other cancer. These studies are currently being reviewed and reassessed.
- Page 134 - #2: Does (did) the water vapor released from cooling towers contain hexavalent chromium?
- Page 141 - 142, #1: Why should you remove the fat before eating a turtle?
Response: PCBs accumulate in the fat of animals, and the fat is easily removed.
- Page 147: What was the function of the Federal Facilities Oversight Unit? Why doesit no longer exist? What took its place? Did you review the data collected by this unit?
Response: The Federal Facilities Oversight Unit (FFOU) was created by the University ofKentucky Water Resources Research Institute as part of a contract with the KentuckyNatural Resources and Environmental Protection Cabinet in order to provide oversight andcoordination of PGDP activities. For more information about the oversight unit, contact theKentucky Department for Environmental Protection, Division of Waste Management. Yes,we reviewed the data collected by this unit.
- What biomarkers did you use to assess a residents exposure to any metal,chemical, or radionuclide?
- What common degenerative diseases (e.g., Parkinson's, Alzheimer's) wereassessed in this health assessment?
- What autoimmune diseases (e.g., rheumatoid arthritis, Lupus) were assessedin this health assessment?
Response: None; ATSDR used measured or modeled environmental concentrations to assessexposure to inorganic compounds, organic compounds, and radionuclides. ATSDR does notrecommend human sampling unless there is a completed exposure pathway at sufficientexposure concentrations to cause potential adverse health effects. ATSDR did not assesscommon degenerative or autoimmune diseases in the PHA.
- Forward: If ATSDR is primarily an advisory agency are the 11recommendations the only advice you are giving the community/DOE/USECas the result of this study?
- Page 156: Most of the 11 recommendations are simply extensions of programsthat are currently in place or proposals that have already been made by otheragencies. Suggestions and recommendations for alternative chemical use,waste minimization processes, innovative cleanup technologies, and so forthwould have been worthwhile.
Response: The recommendations made in the report covered areas that may be in progressbut not completed. As ATSDR worked on this project and noted a concern, we discussedthose concerns with the appropriate agencies. If an appropriate action was taken and/oradditional work was done in that area before our report was drafted, a recommendation wasnot put in the PHA. Suggestions and recommendations for alternative chemical use, wasteminimization processes, and innovative cleanup technologies would not be appropriate inthis document. Most of the contaminants affecting the off-site community were generatedfrom historical uses and practices, and several innovative cleanup technologies are beinginvestigated for this site. Early in this process we passed on information and contacts for thesite to technical persons with experience regarding innovative groundwater clean-uptechnologies.
- Who paid for this Health Assessment and how much did it cost?
Response: Although ATSDR paid for this report, ATSDR receives funds through aMemorandum of Understanding with DOE for work at DOE sites. The question concerningthe cost cannot be addressed until the public health assessment is complete.
- Pentachlorophenol contains 3 dioxins and 3 furans. Dioxin should have been included in this health assessment.
Response: We evaluated pentachlorophenol (with and without dioxin) at PGDP. Refer to ourdiscussion for pentachlorophenol under specific substances in the Public Health Implications section of the report. We evaluated off-site environmental data for dioxin.
- In the past, what media posed the greatest health risk to this community?
- Currently, what media poses the greatest health risk to this community?
- What metal currently poses the greatest health risk to this community?
- What chemical currently poses the greatest health risk to this community?
- What radionuclide currently poses the greatest health risk to this community?
Response: Refer to "Environmental Contamination, Exposure Pathways, and PotentiallyExposed Populations" and "Public Health Implications" in the PHA.
- Did you identify any gene-damaging substances in any media? What are they?
Response: Yes, of the six known human carcinogens identified as contaminants ofconcern, three (arsenic, benzene, and cadmium) are considered to have "gene-damaging" properties.
- Did you identify any reproductive toxin in any media? What are they?
Response: Yes, there were seven reproductive toxins (arsenic, benzene, cadmium,lead, mercury, nickel, and polychlorinated biphenyls (PCBs)) identified ascontaminants of concern in the PHA.
- Did you identify any known carcinogen in any media? What are they?
Response: Yes, there were six known human carcinogens (arsenic, benzene,cadmium, chromium, radon, and vinyl chloride) identified as contaminants ofconcern in the PHA.
- How many PGDP/USEC employees also reside in the study area?
Response: As stated in the Document Notes, we were evaluating potential exposure to theoff-site community. None of the "maximally exposed individuals" discussed in thedocument were PGDP/USEC employees; however, we do realize that several employees livein the neighboring area.
- Has the United States Environmental Protection Agency authorized a set of airemission standards for USEC operations?
Response: This report concerns the DOE and its predecessors activities at this site.
- Where is the McNairy Aquifer monitored in Illinois?
Response: The McNairy Aquifer was not monitored in Illinois; it may not extend across theriver into Illinois. We looked at results of water sampling from a drinking water supply on the Illinois side of the Ohio River, but those samples did not come from the McNairyAquifer.
- Page 151: In conclusion you held that this investigation had determined thedistribution and concentrations of specific chemical and radioactive substancesreleased from PGDP "poses no apparent public health hazard." On page 18 you stateonly a few chemicals were tested for in residential well samples and that you"assumed" what other contaminants could have been in those wells. Is that goodscience? Page 19: For example if certain chemicals were found above comparisonvalues in monitoring wells, near untested residential, why weren't the residential wellstested too in order to form a more complete assessment of human exposure?
Response: Monitoring wells are much better sources for groundwater samples due tospecified construction and design. Residential wells may offer a better measure of potentialexposure; however, some of the residential wells in the Water Policy Area were never testedfor some potential contaminants and are no longer being used. Some residential wells havebeen converted to monitoring wells and may have been tested for additional potentialcontaminants after residents were no longer drinking the water. We used well samplingresults from monitoring wells that had been residential wells or monitoring wells closest tothe unused residential wells and samples collected closest to the time when residents were drinking well water.
- Page 12: "...releases from...process facilities...have dramatically decreased; releases from other sources...have increased." Was there a net gain or a net loss of releases to the environment during the 1990's?
Response: Net loss. The main increase was seen in the groundwater plumes. The maindecreases were seen in airborne and surface water releases. Refer to the section"Environmental Contamination, Exposure Pathways, and Potentially Exposed Populations"for more details.
- Page EX-2: "Currently, we have no reports of health effects related to this accident...." What 1960-1964 health data did you review, who did you interview, and do you believe latent health effects could have occurred? "...however, if data become available...." Forty years later where do you expect that data to come from?
Response: We discussed this time frame with several people in the area representing different professions and community members; however, it was thirty-five to forty years ago and we realize that some people may no longer be in the area. The most immediate adverse health effect to a person maximally exposed off-site during this incident would have been respiratory irritation from the hydrogen fluoride exposure followed by detectable, non-permanent kidney damage from uranyl fluoride exposure. Also, this person may have a slight increased lifetime risk for lung cancer.