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PUBLIC HEALTH ASSESSMENT

NATIONAL ZINC COMPANY
BARTLESVILLE, WASHINGTON COUNTY, OKLAHOMA


APPENDICES

Appendix 1

Figure 1

Figure 1
Appendix 1, Figure 1 - Map of the Proposed National Zinc
Company National Priorities List Site, Bartlesville, OK



Appendix 2
Health Comparison Values

Health comparison values for the Agency for Toxic Substances and Disease Registry (ATSDR)public health assessments are contaminant concentrations that are found in specific media (air,soil, and water) and that are used to select contaminants for further evaluation. The valuesprovide guidelines that are used to estimate a dose at which health effects might be observed. The health comparison values were developed by using the most conservative assumptions (i.e.,worse case). For example, soil health comparison values are developed for children who exhibitpica behavior. Soil ingestion in pica children greatly exceeds the soil ingestion rate for thenormal population. Health comparison values used in the Environmental Contamination andOther Hazards and the Public Health Implications sections of this public health assessment arelisted and described below.

Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations that wouldbe expected to cause no more than one excess cancer in a million (10E-6) persons exposed overa lifetime. CREGs are calculated from EPA's cancer slope factors.

Environmental Media Evaluation Guides (EMEGs) are based on ATSDR's minimal risk levels(MRLs) and factor in body weight and ingestion or inhalation rates. Reference Dose MediaEvaluation Guides (RMEGs) are the same as EMEGs, except that they are based on the U.S.Environmental Protection Agency (EPA) reference doses (RfDs).

An MRL is an estimate of daily human exposure to a chemical (in mg/kg/day) that is likely to bewithout an appreciable risk of deleterious effects (noncarcinogenic) over a specified duration ofexposure. MRLs are based on human and animal studies and are reported in the ATSDRToxicological Profiles for acute (< 14 days), intermediate (15-365 days), and chronic (> 365days) exposures.

EPA's RfD is an estimate of the daily exposure to a contaminant that is unlikely to cause adversehealth effects. However, RfDs do not consider carcinogenic effects.



Tables 1 and 2

Appendix 3.

Environmental Exposure Pathways - Completed Environmental Exposure Pathways at the Proposed National Zinc Company
National Priorities List Site
Pathway
Name
Point of
Exposure
Route of
Exposure
Exposed
Population
Time of
Exposure
Contaminants of
Concern
Estimated
Exposed
Population
Surface SoilThe Smelters
and Surrounding
Residential
Areas
Ingestion
Inhalation
Skin Contact
Smelter
Workers and
Residents near
the Smelter
Past
Present
Future
Cadmium
Lead
Zinc
More Than
5,000
AirThe Smelters
and Surrounding
Residential
Areas
Inhalation
Ingestion
Skin Contact
Smelter
Workers and
Residents near
the Smelter
PastCadmium
Lead
Zinc
Sulfuric Acid
More Than
5,000


Appendix 3.

Table 2 - Potential Environmental Exposure Pathways at the Proposed National Zinc Company National Priorities List Site
Pathway NamePoint of ExposureRoute of ExposureExposed PopulationTime of
Exposure
Contaminants
of Concern
Estimated Exposed
Population
Sediment and
Surface Water
The Smelters and
Ditches off the
Facility
Ingestion
Inhalation
Skin Contact
Smelter Workers
and Residents near
the Smelter Who
Visit the Ditches
Past
Present
Future
Arsenic
Cadmium
Lead
Manganese
Nickel
Zinc
Unknown
Biota
(Plants)
Residential AreasIngestion
Skin Contact
Residents near the
Smelter with
Gardens
Past
Present
Future
Cadmium
Lead
Zinc
Unknown
GroundwaterFormer Wells
within a Three
Mile Radius of the
Smelters and
Wells Beyond the
Radius
Ingestion
Inhalation
Skin Contact
ResidentsPast
Present
Future
Arsenic
Cadmium
Lead
Manganese
Unknown
Residual Piles
and Subsurface
Soils
The Smelter and
Surrounding
Residential Areas
Inhalation
Ingestion
Skin Contact
Smelter Workers
and Residents Near
the Smelter
Present
Future
Arsenic
Cadmium
Lead
Manganese
Nickel
Zinc
Unknown





Appendix 4.

Comparison of Estimated Exposure Doses
to Health Guidelines
TABLE 1 - COMPARISON OF ESTIMATED EXPOSURE DOSE TO HEALTH GUIDELINES FOR INGESTION ORINHALATION*
CONTAMINANTEXPOSURE
PATHWAY
HEALTH
GUIDELINE
SOURCEHEALTH GUIDELINE
EXCEEDED BY
EXPOSURE DOSE
CadmiumResidential Surface
Soil
0.0007 mg/kg/dayMRL#YES
CadmiumAmbient Air 0.0006 µg/m3CREG@YES
ZincResidential Surface
Soil
0.3 mg/kg/dayRfD&YES, but only for
children and pica children
* - An explanation of how exposure doses are calculated can be found after this Table.
# - MRL is Minimal Risk Level (chronic).
@ - CREG is Cancer Risk Evaluation Guides.
& - RfD is reference dose.
mg/kg/day - milligram of contaminant per kilogram of body weight per day.
µg/m3 - micrograms of contaminant per cubic meter of air.

Calculation of Exposure Doses for Soil Ingestion

The exposure doses for soil ingestion were calculated in the following manner. The maximum concentration for a contaminant wasmultiplied by the soil ingestion rate for adults, 0.0001 Kg/day; children, 0.0002 Kg/day; or pica children, 0.005 Kg/day. (The habit ofingesting large amounts of soil is called pica.) This product was divided by the average weight for an adult, 70 Kg (154 pounds) orfor a child, 10 Kg (22 pounds). Those calculations assume that there is frequent daily exposure to soil contaminated at the maximumlevel. A qualitative summary of these results can be found in the table above.


Appendix 5 - Response to Comments Received during the Public
Comment Period for the National Zinc
Company Public Health Assessment

The National Zinc Company (NZC) Public Health Assessment was available for public reviewand comment from September 21, 1994, through November 20, 1994. The Public CommentPeriod was announced in the Tulsa World and the Bartlesville Examiner-Enterprise. Copies ofthe public health assessment were made available for review at the Westside Community Centerand the Bartlesville Public Library. In addition, the public health assessment was sent to ninepersons or organizations. On October 13, 1994, the Agency for Toxic Substances and DiseaseRegistry (ATSDR) held a Public Meeting at the Westside Community Center. The PublicMeeting was arranged so that the public could discuss the findings of the NZC Public HealthAssessment with ATSDR and to permit the public to provide ATSDR with any comments.

During the Public Comment Period, ATSDR received comments from two individuals, twoconsulting firms, the Oklahoma State Department of Health (OSDH), and the OklahomaDepartment of Environmental Quality (ODEQ). Comments and ATSDR responses aresummarized below. The comment letters can be requested from ATSDR through the Freedomof Information Act.

Comment:I would like to request an additional 30 days beyond the October 20, 1994, date tomake a public comment regarding the Health Assessment of NZC.

Response:ATSDR extended the Public Comment Period for the NZC Public HealthAssessment until November 20, 1994.

Comment:Since the Resource Conservation and Recovery Act (RCRA) and Superfund areseparate divisions, but both involved in cleanup recommendations and activities,there needs to be some cooperation within U.S. Environmental Protection Agency(EPA) to co-ordinate (or at least interpret for the public) what their current andfuture recommendations will be for both divisions. Citizens should have someinput on RCRA recommendations as they do with Superfund.

Response:Because ATSDR is an independent non-regulatory agency separate from the EPAand the ODEQ, we can not direct these agencies to coordinate their activities. However, ATSDR will submit your comment and concern to the appropriateindividuals within EPA and ODEQ.

Comment:Footnote 5 on page 29 should be revised to read as follows: "The Maternal andChild Health Service, Oklahoma State Department of Health (OSDH), conductedthe blood lead testing in collaboration with the OSDH environmental unit. TheOSDH environmental unit became a part of the Oklahoma Department ofEnvironmental Quality in 1993. This unit continues to oversee the overallcommunity activities."

Response:The public health assessment has been revised accordingly.

Comment:The response to question 4, "Is Multiple Sclerosis (MS) caused by lead and/orcadmium?", goes into detail that is not pertinent to the issue being discussed. OSDH would like to recommend that a significant portion of this response bedeleted.

Response:The public health assessment has been revised as recommended.

Comment:Change the last sentence of the first full paragraph on page 33 to read as follows:
    Exposure to sulfuric acid air emission could have resulted in irritation tothe eye, nose, throat, and skin at the time of exposure, but does not pose acurrent threat to the health of individuals in this area.
Response:The public health assessment has been revised as recommended.

Comment:Summary, paragraph three, line eight. The ODEQ believes that the use of"National Zinc Site" or " historical smelter operations" should be utilized to avoidconfusion as to the current status of the Zinc Corporation of America facilitywhich is not included in the National Zinc Company CERCLIS site.

Response:The public health assessment has been revised to avoid the confusion.

Comment:Page 3, paragraph five, line four. The use of the word "safe" would appear toinappropriate; we would suggest substitution by "acceptable."

Response:Based upon current scientific information, the blood lead levels detected in theBartlesville children were above levels which are known not to be safe (i.e.,adverse health effects could occur) or acceptable by current guidelines. ATSDRprefers the term "safe" because it not only indicates that health officials havedetermined that these levels are not acceptable but that adverse health effectscould occur.

Comment:Page 5, paragraph two. Dr. Edd Rhoades, chief of Pediatrics, Oklahoma StateDepartment of Health conducted medical education regarding lead exposureduring 1992.

Response:This information has been added to the public health assessment. Thank you forproviding it to ATSDR.

Comment:Page 5, paragraph three. Discussion of actions regarding the "National Zinc Site"under the Comprehensive Environmental Response, Compensation, and LiabilityAct (CERCLA) and actions regarding the Zinc Corporation of America facilityunder RCRA should be separated to avoid confusion.

Response:The public health assessment has been revised as recommended.

Comment:Page 8, paragraph two, last sentence. Appendix 2 contains no listing of the healthcomparison values; these appear in Tables 1, 2, and 3.

Response:The public health assessment has been revised to avoid the confusion.

Comment:Page 21, paragraph one. The value being referred to as "exposure dose" is inactuality an "exposure level" or "estimated chronic intake" rather than a dose. The use of the term "dose" is misleading.

Response:The use of the term "exposure dose" is being used in accordance with the ATSDRPublic Health Assessment Guidance Manual.

Comment:Page 21, paragraph three. The statement that there are no health guidelines forexposure to lead in soil is inaccurate. EPA and ODEQ have set action guidelinesfor interpretation of lead concentrations in soil of 500 ppm in residential areas. The underlying basis for this guideline is the protection of human health.

Response:ATSDR has not been able to establish a minimal risk level (MRL) for leadbecause a threshold has not yet been defined for the most sensitive effects of lead(i.e., neurotoxicity). EPA has not been able to establish a reference dose (RfD)for the same reason. The action level discussed by the commentator wasestablished to help site investigators determine whether additional soil samplingshould be conducted at a site. The guidelines do not establish any healthguidance and should not be used to predict health outcomes.

Comment:Page 22, paragraph one under a. Cadmium, Soil. The soil concentrationpresented as acceptable (non-pica children) for cadmium, 375 parts per million(ppm), is considerably above the risk based level proposed for residential areas bythe ODEQ in the Proposed Plan (100 ppm) which is criticized by ATSDR in theircomments on the ODEQ Proposed Plan, dated October 12, 1994. It would appearthat ATSDR is inconsistent in what is considered to be an acceptable level ofcadmium in soil.

Response:In the latter part of the paragraph cited by the commentator, ATSDR states:
    "For small children who ingest large amounts of soil (i.e., pica children),the lowest effects level is exceeded when the cadmium level exceeds 15mg/kg (sic ppm)."

In ATSDR's comments to ODEQ concerning the Proposed Plan, ATSDR did notrecommend a cleanup level. ATSDR only provided ODEQ with it's opinion onwhat factors should be considered and evaluated when developing a cleanuplevel. Therefore, ATSDR does not believe it is being inconsistent.

Comment:Page 23, paragraph one (Air) and paragraph five (Risk of Cancer). Themaximum air concentration (0.61 micrograms of cadmium per cubic meter of air[µg/m3]) cited was determined to be an invalid sample by EPA and ODEQ. Therefore, the use of an invalid sample point to determine risk of cancer isinappropriate. We would suggest the use of the average air value or presentationof risk by a range based on the range of concentrations measured in the area.

Response:The public health assessment has been revised to correct this misunderstandingand to clarify the agency's opinion

Comment:Page 23, paragraph five (Risk of Cancer). The structure of the paragraph ismisleading. The reference to the cadmium smelter worker study which identifieda two fold increase in the rate of lung cancer could be read to refer to thehistorical smelter operation in Bartlesville. This not the case. The paragraphshould be rewritten to clarify that the data from the study are not reflective of theconcentrations associated with the National Zinc site.

Response:The public health assessment has been revised to avoid the confusion.

Comment:Page 24, c. Sulfuric Acid. The discussion regarding the fact that currentexposures to sulfuric acid are not present in the area and that health consequencesrelated to the 1977 releases would not be occurring in the present needs to bestrengthened here and in the Summary and Conclusions Sections.

Response:This issue was also raised by another commentator. The public health assessmenthas been revised as recommended.

Comment:Information concerning the 1977 through 1979 Environmental ConsultantsLaboratory blood lead study was not included in the public health assessment.

Response:This information has been added to the public health assessment (i.e.,Background and Review of Blood Contaminant Data sections). Thank you forbringing this information to the attention of the Agency.

Comment:Page 32, response to questions 4. The inclusion of the material relating multiplesclerosis and latitude is misleading. It is not clear what significance this materialhas to the question that was posed and the situation in Bartlesville.

Response:This issue was also raised by another commentator. The public health assessmenthas been revised as recommended.

Comment:Page 34, A. Public Health Actions Taken. The commentator provided ATSDRwith information which should be included in this section.

Response:ATSDR appreciates receiving this information and has included it in theappropriate sections of the public health assessment.

Comment:The inclusion of zinc as a contaminant of concern is problematic. In the baselinerisk assessment prepared for EPA by CH2M Hill, the RemedialInvestigation/Feasibility Study (RI/FS) and the proposed plan have all indicatedthat the contaminants of concern at the site included lead, cadmium, and arsenic. Zinc has been determined to be of significance as an ecological concern.

Response:In accordance with the ATSDR Public Health Assessment Guidance Manualhealth comparison values are used to determine which contaminants should belooked at more closely in the public health assessment. As stated in theEnvironmental Contamination and Other Hazards section:

"A contaminant is selected for further evaluation if the contaminant concentrationin a valid environmental sample exceeds comparison values. The presence of acontaminant on the lists in the tables of this section does not mean that eitherexposure to the contaminant or adverse health effects has occurred or will occur. Inclusion in the list indicates only that the potential for human exposures to theselected contaminants and the potential for adverse human health effects as aresult of any exposures to the selected contaminants will be discussed in moredetail in later sections of this Public Health Assessment."

ATSDR evaluates the possible toxicological effects of zinc in the ToxicologicalEvaluation section of the public health assessment. In that section, ATSDR statesthat there is some possibility of noncarcinogenic health effects for childrenexposed to zinc in residential soil. However, it is uncertain that these healtheffects would occur because of the different zinc metabolism between adults andchildren.

Comment:ATSDR has failed to consider the off-site groundwater monitoring data thatindicate groundwater is not a potential exposure pathway. The commentatorprovided ATSDR with copies of their investigation reports.

Response:ATSDR appreciates receiving the off-site groundwater monitoring data. The datawill be included in the public health assessment and the conclusions andrecommendation will be changed as appropriate.

It should be noted that the investigation reports were submitted to EPA justbefore and during the Public Comment Period for the NZC Public HealthAssessment. Therefore, this information was not available to ATSDR in order todevelop the public comment release public health assessment.

Comment:Air monitoring data show that dust from the residue piles is not a threat to publichealth. The commentator provided ATSDR with copies of their investigationreport.

Response:ATSDR appreciates receiving the air monitoring data. The data will be includedin the public health assessment and the conclusions and recommendation will bechanged as appropriate.

It should be noted that the investigation reports were submitted to EPA justbefore and during the Public Comment Period for the NZC Public HealthAssessment. Therefore, this information was not available to ATSDR in order todevelop the public comment release public health assessment.

Comment:ATSDR has overestimated risk, casting doubt on it's conclusions andrecommendations. The commentator made eight specific points.

Response:ATSDR does not believe it has overestimated the possible risk associated with theNZC Site. ATSDR will respond to each of the commentators points.

Comment:Point 1. An overly conservative target risk level for use in evaluating need forremediation.

Response:The target risk levels cited by the commentator are the health comparison valuesin the public health assessment. In accordance with the ATSDR Public HealthAssessment Guidance Manual health comparison values are used to determinewhich contaminants should be looked at more closely in the public healthassessment. As stated in the Environmental Contamination and Other Hazardssection:

"A contaminant is selected for further evaluation if the contaminant concentrationin a valid environmental sample exceeds comparison values. The presence of acontaminant on the lists in the tables of this section does not mean that eitherexposure to the contaminant or adverse health effects has occurred or will occur. Inclusion in the list indicates only that the potential for human exposures to theselected contaminants and the potential for adverse human health effects as aresult of any exposures to the selected contaminants will be discussed in moredetail in later sections of this Public Health Assessment."

ATSDR evaluates the possible toxicological effects for each of the contaminantsselected (i.e., above health comparison values) in the Toxicological Evaluationsection of the public health assessment. In this section, ATSDR discusses thepossible health effects and the uncertainty of the toxicological information.

The ATSDR Minimal Risk Levels (MRLs) and Cancer Risk Evaluation Guides(CREGs) used in this public health assessment come from the chemical specificATSDR Toxicological Profile. Each Toxicological Profile is peer reviewed andreleased for public comment. Each Toxicological Profile describes how eachMRL and CREG is developed.

It is important to note that ATSDR did not base its conclusions andrecommendations solely on the toxicological information. The blood lead studieshave consistently shown that children living near the smelter have blood leadlevels above the Centers for Disease Control and Prevention guidelines.

Comment:Point 2. A flawed RfD for zinc, especially as applied to infants and children.

Response:ATSDR agrees that there is some uncertainty associated with the zinc RfD as itapplies to infants and children. In the toxicological section, ATSDR states thatthere is some possibility of noncarcinogenic health effects for children exposed tozinc in residential soil. However, ATSDR is uncertain whether these healtheffects would occur because of the different zinc metabolism between adults andchildren (page 24 of the public comment release public health assessment).

Comment:Point 3. Use of a single maximum value for a metal in soil to estimate exposure.

Response:ATSDR did not only use a single maximum value for estimating exposure. In theToxicological section, ATSDR indicates at what environmental soil concentrationexposures would exceed an ATSDR Minimal Risk Level (MRL) or EPAReference Dose (RfD). For example, on page 22 of the public comment releasepublic health assessment ATSDR states:

"Soil concentrations of cadmium of 375 mg/kg and greater result in exposuredoses for small children (10 kilograms [Kg]/22 lbs) that exceed the lowestobserved effect level in humans of 0.0075 milligrams of cadmium per kilogrambody weight per day (mg/kg/day). For small children who ingest large amountsof soil (i.e., pica children), the lowest effects level is exceeded when the cadmiumlevel exceeds 15 mg/kg. Cadmium soil levels in the community around the ZincCorporation facility vary from 0.2 - 1,372 mg/kg."

Comment:Point 4. The inclusion of the pica child to evaluate chronic effects.

Response:In accordance with the ATSDR Public Health Assessment Guidance Manual, thepossible toxicological effects for all people living and working at a site, includingsub-populations (i.e., pica children), should be discussed in a public healthassessment. ATSDR agrees that there is some uncertainty as to how much andhow long a child ingests soil. As indicated in the response to sub-commentnumber 3, even non-pica children may be exposed to cadmium in soil at levels ofpublic health concern. Therefore, ATSDR conclusions are not based solely onthe possible exposures to pica children.

Comment:Point 5. Lack of consideration of the bioavailability of metals in soil.

Response:Bioavailability of metals in soils is an issue that needs to be considered whenevaluating the toxicity of metals found in soils. However, bioavailability isdependent upon site-specific conditions (e.g., chemical species of the soils andmetals, the nutritional status of the exposed population, etc.).

ATSDR is familiar with the site-specific bioavailability study conducted by PTIEnvironmental Services. However, this study does have some limitations. Theprimary limitation is that the rodent is not the best model for representingbioavailability in a child. The pig is thought to be a better animal model formetal bioavailability studies (Weis CP and Lavelle JM. Characteristics toconsider when choosing an animal model for the study of lead bioavailability. Chemical Speciation and Bioavailability. 1991;3(3-4):113-119.). In addition, theregimen of introducing the contaminants with the feed may alter bioavailability. A child may ingest soil or dust on an empty stomach. This would result in moremetal uptake. The animal model also does not represent a child or infant withpoor nutrition, a possible situation at the NZC site. Therefore, ATSDR decidedthat there is not any good site-specific bioavailability data.

Most of the toxicological studies cited by ATSDR reported the exposure dose(dose in the feed) given to the animals. In addition, the epidemiologic workerstudies cited by ATSDR reported the environmental concentrations (exposuredoses) that the workers were exposed to. Given the uncertainty surrounding thebioavailability of metals and the differences between animal and human metaluptake, ATSDR compared the exposure dose of the animals and the exposuredose of the workers in the epidemiologic studies to the exposure doses that thepeople near the NZC site may experience. In addition, ATSDR relied upon theresult of the blood lead and blood cadmium studies. These studies indicate thatpeople near the site have higher blood lead and blood cadmium levels than peoplefarther away from the site. ATSDR came to its conclusions by using this weightof evidence approach.

Comment:Point 6. Lack of consideration of antagonistic interactions between cadmium andzinc.

Response:ATSDR has added a new sub-section to the public health assessment whichdiscusses the interaction between cadmium, lead, and zinc. The information isbased upon the ATSDR Toxicological Profiles for cadmium, lead, and zinc.

Comment:Point 7. Failure to incorporate site-specific data on the transfer of metals fromsoil to dust. Specifically, using the default values in the EPA Integrated ExposureUptake Biokinetic Model for lead in children (IEUBK).

Response:ATSDR is very familiar with the IEUBK. ATSDR's believes that the IEUBKshould not be used to predict health outcomes. In addition, ATSDR believes thatthe IEUBK should not be used as the sole basis for selecting the lead cleanuplevel at this site or any other site. The IEUBK is not validated for all sites andsituation and does not take into account all of the health aspects needed to beconsidered when trying to determine possible health outcomes or when selectinga soil cleanup level. For example; the type and variation of soil cover within thearea, the nutritional status of the population within the area, and the possibleinteractions between lead and the other site-related contaminants may allinfluence exposure and need to be considered and evaluated.

Comment:Point 8. No consideration of results from recent studies demonstrating a minimal,if any, impact on blood lead levels after soil removal. The commentatorspecifically cited the EPA's Three-City Lead study.

Response:ATSDR is familiar with the Three-City Lead study. Although the study was verylarge and well conducted, it does have some limitations. The main limitation isthe study did not determine where the study children played and spent their timeoutside. Therefore, the study may have a significant exposure bias. ATSDRbelieves the Three-City Lead study is a significant step in understanding therelationship between lead poisoning and the sources of lead. However, additionalstudies are needed to confirm the Three-City Lead study results.

The results of the Three-City Lead study can not be directly related to thesituation in Bartlesville. As discussed above, various site-specific factorsinfluence the bioavailability of lead and other metals. The specific situations atthe three cities in the EPA study (Baltimore, Boston, and Cincinnati) are differentfrom Bartlesville (e.g., the NZC smelter).

Comment:The draft public health assessment is irrelevant and misleading. The draft publichealth assessment was issued out of sequence to the RI/FS report. Its' conclusionsconflict with those in the Proposed Plan.

Response:ATSDR does not believe the public health assessment is irrelevant andmisleading. As required by the CERCLA, as amended by the SuperfundAmendments and Reauthorization Act (SARA), ATSDR must conduct a publichealth assessment within one year of a site being proposed for listing on theNational Priorities List (NPL) (a.k.a., "Superfund"). In accordance withATSDR's procedures, an initial release public health assessment for the proposedNational Zinc Company site was completed one year after the proposed listing. The initial release was reviewed by EPA and the State of Oklahoma.

ATSDR is not aware of any conflict between the public health assessment and theProposed Plan to clean-up the NZC site. The public health assessment concludesand recommends that the site should be remediated. The Proposed Plan describesremedial action alternatives considered for addressing the elevated metalconcentrations in the soil at the NZC site and identifies the remedial actionselected by the ODEQ. The public health assessment does not recommend howand to what extent the site should be remediated.

Comment:The document should be withdrawn or significantly revised. We stronglyrecommend that the draft public health assessment either be withdrawn or berevised to focus only on the evaluation of epidemiological data in response tocommunity health concerns. The document should simply refer the reader to theEPA baseline risk assessment and the ODEQ Proposed Plan.

Response:ATSDR has revised the NZC Public Health Assessment to include thegroundwater and ambient air monitoring data provided by two commentators. These additional data did not change ATSDR's major conclusion that the NZCsite is a public health hazard.

As required by the CERCLA, as amended by the SARA, an ATSDR public healthassessment is required to evaluate the nature and extent of contamination,pathways of human exposures, and the size and susceptibility of communitieswithin the likely pathways. In order to comply with this congressional mandate,ATSDR must conduct its' own evaluation. ATSDR can not simply refer thereader to other reports. This public health assessment was conducted inaccordance with the ATSDR Public Health Assessment Guidance Manual.

Comment:The draft public health assessment should have been issued before the publiccomment period for the RI/FS and certainly before issuance of the ODEQ'sProposed Plan.

Response:On May 15, 1994, ATSDR issued the initial release public health assessment forthe proposed NZC NPL site. In accordance with ATSDR procedures, the initialrelease completed ATSDR's statutory requirements under CERCLA. Both EPAand ODEQ were provided copies of the initial release prior to the release of theEPA risk assessment or the ODEQ Proposed Plan.

ATSDR would have preferred to have issued the public comment release of thispublic health assessment prior to the draft RI/FS. However, the acceleratedinvestigation and cleanup of this site, which ATSDR fully supports, resulted inthe public comment release being issued sightly after the draft RI/FS wasreleased.

Comment:ATSDR should explain the inconsistencies and errors in the draft public healthassessment to the community. Specific examples were provided by thecommentator.

Response:ATSDR will respond, below, to each of the specific comments.

Comment:Page 1, last paragraph, 2nd bullet. Evaluation of groundwater as a threat tohuman health should not be considered as a recommended action.

Response:Based upon the data submitted by another commentator, ATSDR agrees that thegroundwater monitoring recommendation is not necessary. The public healthassessment has been revised accordingly.

Comment:Page 4, 4th paragraph, last sentence. EPA removed soils from 25 (not 29) highaccess areas and from 10 (not 11) residences.

Response:The NZC Public Health Assessment has been revised accordingly.

Comment:Page 5, 3rd paragraph, 2nd sentence. This sentence regarding finalization of NPLlisting is incorrect.

Response:The sentence has been deleted from the public health assessment.

Comment:Page 5, 5th paragraph, 3rd sentence. Final cleanup levels were not presented inEPA's risk assessment but in the Proposed Plan by ODEQ based on informationpresented in EPA's risk assessment and the RI report.

Response:The public health assessment has been revised accordingly.

Comment:Page 8, 3rd full paragraph, 1st sentence. ATSDR did not evaluate "... allavailable environmental monitoring data (1971 to present)." That is the crux ofthe problem.

Response:ATSDR was not provided a copy of the RI/FS until September 14, 1994. Thepublic health assessment was issued on September 7, 1994. The relevant data inthe RI/FS has been added to the public health assessment.

Comment:Page 17, 1st paragraph, 2 sentence. This sentence is incorrect and indicatescareless interpretation of data. Cadmium and lead could not have beendischarged from the smelter as indicated by the 1977 and 1992 ambient air databecause smelter discharges ceased after 1976.

Response:As required by the Emergency Planning and Community Right-to-Known Act of1986, the owners of the smelter reported to EPA that the Zinc Corporation ofAmerica released to the air an average of 3,429 pounds of lead, 1,474 pounds ofcadmium, and 23,600 pounds of zinc each year for the years 1987 to 1991. Thisinformation is presented and discussed in the public comment release publichealth assessment.

Comment:Page 18, last paragraph, 2nd sentence. This sentence is not correct. The RI dataindicated that garden soils had significant lower concentrations of arsenic,cadmium, lead, and zinc than soils from the same yard.

Response:This information will be incorporated into the public health assessment. This partof the public health assessment discusses the potential exposure pathways. Although this information indicates that the gardens sampled to date do notappear to have significant metal concentrations, it does not preclude that gardensin the past could have had significant metal concentrations which could have beentaken-up by plants.

Comment:Page 19, 1st paragraph. Analysis of soil samples near the Caney River are notparticularly relevant to sediments in the Caney River downstream of Eliza Creek. The facility ditch sediment sample referred to in the draft public healthassessment (Table 1) is not from "... local drainage ditches near the Caney River."

Response:Nowhere in this paragraph does ATSDR refer to the sediment data contained inTable 1. This paragraph discusses the sediment data taken in Eliza Creek and inCaney River. Table 1 clearly states that the environmental data presented wastaken from locations at the Zinc Corporation of America.

This paragraph has been revised to clearly state how the agency came to itsconclusion. The data presented in the RI will also be included in this discussion.

Comment:Page 22, Section 2. The possibility of health consequences. These evaluationsfor cadmium and zinc are preliminary, screening level evaluations that aresuperseded by the more exhaustive, site-specific analysis in the RI.

Response:This part of the public health assessment was developed in accordance with theATSDR Public Health Assessment Guidance Manual.

Comment:Page 23, 5th paragraph. Regarding the cancer risk associated with cadmiuminhalation, it is important to note that no single individual will be exposed to themaximum observed cadmium concentration (0.61 µg/m3) for a lifetime.

Response:This section of the public health assessment has been revised to clarify this issue.

Comment:Page 23, 6th paragraph and page 24, 1st full paragraph. The inclusion of zinc asa contaminant of concern is problematic. A flawed RfD for zinc was used andapplied to infants and children. ATSDR did not consider the antagonisticinteractions between cadmium and zinc.

Response:ATSDR agrees that there is some uncertainty associated with the zinc RfD as itapplies to infants and children. In the toxicological section, ATSDR states thatthere is some possibility of noncarcinogenic health effects for children exposed tozinc in residential soil. However, ATSDR is uncertain that these health effectswould occur because of the different zinc metabolism between adults and children(page 24 of the public comment release public health assessment).

ATSDR has added a new sub-section to the public health assessment whichdiscusses the interaction between cadmium, lead, and zinc. The information isbased upon the ATSDR Toxicological Profiles for cadmium, lead, and zinc.

Comment:Page 28, 4th paragraph. The only recent body tissue data available are for lead,consequently there is no evidence that site-related cadmium exposures areoccurring at the present time. Moreover, the results of a body tissue monitoringstudy recently conducted by ATSDR in Palmerton, Pennsylvania suggests thatsignificant cadmium exposures are not currently occurring in Palmerton. Becauseof the similar histories of the two sites and because the environmental cadmiumexposures would have been significantly less in Bartlesville, the results of theATSDR study in Palmerton strongly indicate that significant cadmium exposuresare not currently occurring in Bartlesville.

Response:The public health assessment has been revised to clearly indicate that there is nobody tissue data for cadmium.

The ATSDR study in Palmerton found significantly higher urine cadmium levelin people from the target area than in the comparison area (ages 40 through 75). ATSDR was not able to determine whether this difference was due to past orcurrent exposures. The results of the Palmerton study can not be directly relatedto the situation in Bartlesville. The demographic make-up of Palmerton isdifferent than Bartlesville. In addition, Bartlesville has a different soil matrixthan Palmerton.

Comment:Page 29, 5th paragraph. In explaining the wide range of increases in blood leadlevels associated with lead in soil, it is important to note that the smallestincreases in blood lead levels were observed in communities with mines orinactive smelters. This observation has been explained by studies demonstratingreduced absorption of lead from these soils.

Response:This information has been added to the public health assessment.

Comment:Page 33, Recommendation No 2 regarding determination of the total extent ofgroundwater contamination. This recommendation is not relevant.

Response:Based upon the data submitted by another commentator, ATSDR agrees that thegroundwater monitoring recommendation is not necessary. The public healthassessment has been revised accordingly.

Comment:Page 33, Recommendation No. 3. Air emissions from the residual piles are beingcontrolled as indicated by the ongoing ambient air monitoring program under theoversight of EPA Region VI. This recommendation is not relevant.

Response:Based upon the data submitted by another commentator, ATSDR agrees. Thisrecommendation has been revised to state that the control of air emissions fromthe residual piles should continue.



FOOTNOTES

1. The National Toxicology Program in its Annual Report onCarcinogens classifies a chemical as a "known human carcinogen"based on sufficient human data. Its classification of a chemicalas being "reasonably anticipated to be a carcinogen" is based onlimited human or sufficient animal data.

2. IARC defines a class 1 carcinogen as a substance whichstudies in humans indicate a causal relationship between the agentand human cancer. Class 2 carcinogens are those reasonablyanticipated to be carcinogens. For a 2A classification, there islimited evidence of carcinogenicity from human studies whichindicate that a causal interpretation is credible, but notconclusive. A classification of 2B indicates that there issufficient evidence of carcinogenicity from studies in experimentalanimals.

3. In EPA's classification scheme, a chemical is considered aclass A or human carcinogen based on sufficient evidence fromstudies of humans. A substance is considered class B1 if there islimited evidence from human studies. B2 is used when evidence forcarcinogenicity is inadequate or non-existent based on humanstudies, but sufficient based on animal studies.

4. Category I: The substance meets the definition of apotential occupational carcinogen in (i) humans, or (ii) in asingle mammalian species.
Category II: The substance (i) meets the definition of a potentialoccupational carcinogen but the evidence is suggestive.

5. The Maternal and Child Health Service, Oklahoma StateDepartment of Health (OSDH), conducted the blood lead testing incollaboration with the OSDH environmental unit. The OSDHenvironmental unit became a part of the Oklahoma Department ofEnvironmental Quality in 1993. The unit continues to oversee thiswork.

6. Personal communication with Monty Elder, Oklahoma Departmentof Environmental Quality.


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