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PUBLIC HEALTH ASSESSMENT

ASARCO HAYDEN SMELTER SITE
(a/k/a ASARCO INCORPORATED HAYDEN PLANT)
HAYDEN, GILA COUNTY, ARIZONA


6.0 CONCLUSIONS

  • Exposure to sulfur dioxide levels measured in air from the ASARCO facility occasionally poses a short-term public health hazard to sensitive asthmatics. The levels found do not appear to pose a health hazard to persons without sensitive airways or asthma.

  • Other exposures to contaminants in other environmental media do not appear to pose a public health hazard.

Data Gaps

Because of the lack of data regarding the long-term effects of exposure to low levels of sulfurdioxide, it is unknown whether a long-term health hazard exists in the area.

Although environmental or dietary factors that resulted in urinary arsenic levels in excess of the30 µg/L action level for 5 of the 224 individuals tested for urinary arsenic were reflected in thesurvey, follow-up interviews with the residents suggested that home renovations may havecontributed to the elevated arsenic levels. However, no follow-up sampling was conducted tobetter define the nature of the exposure, nor was paint testing conducted to confirm the theorythat paint was contributing to the exposure.

Note: Further environmental investigation is currently under way. Results of the new data willbe evaluated for public health implications. Conclusions drawn for this public health assessmentwere based on data available at the time the document was released. Conclusions could change if data indicate that exposure has increased or decreased.


7.0 RECOMMENDATIONS

  • Explore the development of a web-based information system that provides daily sulfurdioxide air quality data to the public. This air quality data would allow asthmatics andpersons with sensitive airways who have access to the Internet to view air quality data and limit physical activity on days that may pose respiratory health problems.

  • Distribute health education material to the local population regarding the health effects from exposure to sulfur dioxide and effective methods of preventing health effects, including limiting outdoor exercise when levels are elevated.

8.0 PUBLIC HEALTH ACTION PLAN

The Public Health Action Plan (PHAP) for the ASARCO Hayden Smelter site contains adescription of actions taken, to be taken, or under consideration by the Agency for ToxicSubstances and Disease Registry (ATSDR) and the Arizona Department of Health Services(ADHS) at or near the site. The purpose of the PHAP is to ensure that this public healthassessment not only identifies public health hazards, but also provides a plan of action designedto mitigate and prevent adverse human health effects resulting from exposure to hazardoussubstances in the environment. ADHS and ATSDR will follow-up on this plan to ensure thatactions are carried out.

Actions Completed

  1. On January 7, 1999, ADHS obtained environmental sampleswithin Hayden andWinkelman to determine both background levels of metals and area levels of thesemetals.

  2. On April 5, 1999, ADHS met with community leaders to learn how the communitywanted to provide and receive information.

  3. On April 19, 1999, ADHS presented the proposed study to the Hayden Town Council.

  4. On May 10, 1999, ADHS presented the proposed study to the Winkelman TownCouncil.

  5. On May 17, 1999, ADHS met with the Hayden Town Council and answered questionsat the meeting.

  6. From June to October 1999, the University of Arizona conducted public healthsurveys of the residents of Hayden and Winkelman. Blood lead levels were evaluatedfor children 6 to 36 months and for some children up to 72 months of age and urinaryarsenic levels were checked in adults and children. All test results were presented tothe participants along with recommendations to seek follow-up care if levels wereelevated above the standards used for this study.

  7. On March 8, 2000, a public notice was posted in the Copper Basin News to advise thepublic of the results of the health survey. Notification of public meetings on March 16,2000 are also given.

  8. On March 16, 2000, findings of the health survey were presented during two meetings in Hayden and Winkelman with local residents.

  9. On May 20, 2002, ADHS presented the Public Health Assessment-Draft for PublicComment to the Hayden Town Council.

  10. On June 10, 2002, ADHS presented the Public Health Assessment-Draft for PublicComment to the Winkelman Town Council.

  11. On June 18, 2002, ADHS presented the Public Health Assessment-Draft for PublicComment during a public meeting at the Senior Center in Hayden.

Actions proposed

  1. ADHS plans to meet with residents to discuss the findings of the ASARCO HaydenSmelter Site Public Health Assessment. The goals of the meeting are to provideinformation about sulfur dioxide and to explain ways to minimize exposure.

  2. ADHS will continue to address community concerns as residents request assistance.

  3. ADHS will collaborate with ASARCO and community leaders to evaluate thepossibility of implementing a sulfur dioxide notification program.

PREPARERS OF REPORT

Arizona Department of Health Services, Office of Environmental Health
Brian W. Hasty, M.T.
Will Humble, M.P.H., Chief, Office of Environmental Health, Principal Investigator


ATSDR Technical Project Officer
Gail Godfrey
Environmental Health Scientist
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
State Program Section


ATSDR Regional Representative
William Nelson
Regional Services, Region IX
Office of the Assistant Administrator


REFERENCES

  1. Marsh GM, Stone RA, Esmen NA, Gula MJ, Gause CK, Rodney S, Prybylski D.1995. A Population-Based case-control study of lung cancer mortality in Gila Basin smeltertowns.

  2. USDHHS 1995. U.S. Public Health Service, Agency for Toxic Substances andDisease Registry. A Population-Based case-control study of lung cancer mortality in fourArizona smelter towns.

  3. USDHHS 1998. U.S. Public Health Service, Agency for Toxic Substances andDisease Registry. Draft Toxicological Profile for Arsenic.

  4. Registry of Toxic Effects of Chemical Substances [database online]. Denver, CO:Micromedex, Inc.; 1998.

  5. USDHHS 1997. U.S. Public Health Service, Agency for Toxic Substances andDisease Registry. Draft Toxicological Profile for Lead.

  6. Bolger PM, Carrington CD, Caper SG et al. 1991. Reductions in dietary leadexposure in the Untied States. Chemical Speciation and Bioavailability 3(314):31-36

  7. Eldred RA, Cahill TA, 1994. Trends in elemental concentrations of fine particlesatremote sites in the United States of America. Atmospheric Environ 28:1009-1019

  8. EPA 1986. Air Quality criteria for lead. Research Triangle Park, NC: USEnvironmental Protection Agency, Office of Research and Development, Office of Healthand Environmental Assessment, Environmental Criteria and Assessment Office. EPA 600/8-83-028F.

  9. EPA 1991d. Maximum contaminant level goals and national primary drinking waterregulations for lead and copper. Federal Register 56: 26461-26564

  10. Angle CR, Marcus A, Cheng I-H, et al. 1984. Omaha childhood blood lead andenvironmental lead: A linear total exposure model. Environmental Res 35: 160-170.

  11. Laxen DP, Raab GM, Fulton M 1987. Children's blood lead and exposure to lead inhousehold dust and water-a basis for an environmental standard lead in dust. Sc. TotalEnviron 66: 235-244

  12. Ryu JE, Ziegler EE, Nelson SE, et al. 1983.Dietary intake of lead and blood leadconcentrations in early infancy. Am J Dis Child 137: 986-991.

  13. Shacklette HT, Boerngen JG. 1972. Elemental composition of surficial materials inthe conterminous United States. Washington D.C.: US Department of the Interior,Geological Survey; Geological Survey Professional Paper no. 1270.

  14. Balmes JR, Fine JM, Sheppard D. 1987. Symptomatic bronchoconstriction after short-term inhalation of sulfur dioxide. American Review of Respiratory Diseases. 136:1117.

  15. Gong, Jr., Lachenbruch PA, Harber P., Linn WS. 1995. Comparative short-term healthresponses to sulfur dioxide exposure and other common stressors in a panel of asthmatics. Toxicology and Industrial Health. 11:467-487.

  16. Horstmann DH, Seal E, Folinsbee LJ, et al. 1988. The relationship between exposure durationand sulfur dioxide- induced bronchoconstriction in asthmatic subjects. American Industrial Hygiene Association. 49: 38.

  17. Sheppard D. 1988. Sulfur dioxide and asthma - a double edged sword? Journal of Allergy and Clinical Medicine. 82:961.

  18. USDHHS. 1998. Toxicological Profile for Sulfur Trioxide and Sulfuric Acid. Agency forToxic Substances and Disease Registry. December 1998.

  19. Burgess J., Carter D., O'Rourke M. 1999. Hayden/Winkelman Arsenic and Lead Survey. Occupational and Environmental Health Unit, University of Arizona Prevention Center. March 2000.

  20. Sullivan J., Krieger G. eds. Hazardous Materials Toxicology- Clinical Principles of Environmental Health. Williams & Wilkins Press. Baltimore, MD. p. 818-823.

APPENDIX 1: ATSDR LEAD MODEL AND EXPOSURE DOSE EQUATIONS


ATSDR LEAD MODEL

Numerous longitudinal and cross-sectional studies have attempted to correlate environmental lead levelswith blood lead levels. The studies have provided a number of regression analyses and correspondingslope factors for various media including air, soil, dust, water, and food. In an attempt to use thisvaluable body of data, ATSDR has developed an integrated exposure regression analysis. This approachutilizes slope values from selected studies to integrate all exposures from various pathways, thusproviding a cumulative exposure estimate expressed as total blood lead. The worktable in the text canbe used to calculate a cumulative exposure estimate on a site-specific basis. To use the table,environmental levels for outdoor air, indoor air, food, water, soil, and dust are needed. In the absenceof such data, default values can be used. In most situations, default values will be background levelsunless data are available to indicate otherwise. Based on the US Food and Drug Administration's TotalDiet Study data, lead intake from food for infants and toddlers is about 5 micrograms per day. In somecases, a missing value can be estimated from a known value. For example, EPA has suggested thatindoor air can be considered 0.03 times the level of outdoor air.

Empirically determined or default environmental levels are multiplied by the percentage of time one is exposed to a particular source and then multiplied by an appropriate regression slope factor. Slope factor studies were based upon an assumption that exposure is continuous. The slope factors can be derived from regression analysis studies that determine blood lead levels for a similar route of exposure. Typically, these studies identify standard errors describing the regression line of a particular source of lead exposure. These standard errors can be used to provide an upper and lower confidence limit contribution of each estimate of blood lead. The individual source contributions can then be summed to provide an overall range estimate of blood lead. While it is known that such summing of standard errors can lead to errors of population dynamics, detailed demographic analysis (e.g., Monte Carlo simulations) would likely lead to a model without much utility. As a screening tool, estimates provided by the table have a much greater utility than single value central tendency estimates, yet still provide a simple-to-use model that allows the health assessor an easy means to estimate source contributions to blood lead [5].


EXPOSURE DOSE EQUATIONS

ADHS used the ATSDR exposure assessment documents to quantify exposure doses for persons living in the Hayden and Winkelman area. The doses were calculated using the following equations:

Inhalation of emissions:

CDI = CA times IR times EF times ED divided by BW times AT

CDI: chronic daily intake (mg/kg/day)
CA: concentrations in air (mg/m3)
IR: intake rate (m3/day)
EF: exposure frequency (days/yr)
ED: exposure duration (yrs)
BW: body weight (kg)
AT : Averaging time (days)

Ingestion of chemicals in soil:

CDI = CS times CF times IR times EF times ED divided by BW times AT

CDI: chronic daily intake (mg/kg/day)
CS: concentrations in soil(mg/kg)
CF: conversion factor (10-6 kg/mg)
IR: intake rate (mg/day)
EF: exposure frequency (days/yr)
ED: exposure duration (yrs)
BW: body weight (kg)
AT : Averaging time (days)

Ingestion of chemicals in water:

CDI = CW times IR times EF times ED divided by BW times AT

CDI: chronic daily intake (ug/l/day)
CW: concentration in water (ug/L)
IR: intake rate (l/day)
EF: exposure frequency (days/yr)
ED: exposure duration (yrs)
BW: body weight (kg)
AT : Averaging time (days)

------------------------------------------------------------------

Variable Assumptions
Variable Assumptions Adults Children
IR(inhalation): 20 10
IR(ingestion, soil): 100 200
IR(ingestion, water): 2 1
EF: 350 350
ED: 30 6
BW: 70 15
AT: 10950 2190

Dermal contact with chemicals in soil:

Absorbed dose = CS times CF times SA times AF times ABS times EF times ED divided by BW times AT

Absorbed Dose: daily intake (mg/kg/day)
CS: Chemical concentration in soil (mg/kg)
CF: Conversion factor (10E-6 kg/mg)
SA: Skin surface area available for contact (cm2/event)
AF: Soil to skin adherence factor(mg/cm2)
ABS: Absorption factor (unitless)
EF: Exposure frequency (events/year)
ED: Exposure duration (years)
BW: Body weight (kg)
AT: Averaging time (period over which exposure is averaged in days)


APPENDIX 2: PUBLIC COMMENTS AND RESPONSES

ADHS and ATSDR provided an opportunity for the public to comment on this document. No publiccomments were received before the end of the comment period on July 5, 2001. ADHS and ATSDRdid receive comments from EPA, ADEQ, and ASARCO.

EPA Comments:

Comment
EPA wrote that the MRL for arsenic of 0.0003 mg/kg-day was exceeded for childhood exposure. The commenter recommended discussing the comparison of estimated exposure doses to the NOAEL in more detail.

Response
ADHS agreed with the comment and re-formatted Section 5.1. Additional discussion about the full range of NOAEL values was also included. Additional language was added that compares estimated exposure doses to the LOAEL range.

Comment
EPA wrote that is it unclear in the text how childhood exposures are examined as it relates to the Child Health Initiative.

Response
The exposure dose calculations for children were clarified in Section 5.1. Text was added to the Child Health Initiative section to tie the concepts together.

Comment
EPA expressed concern that cancer risks from arsenic are not identified.

Response
A discussion of cancer risks was included for arsenic exposure.

Comment
EPA wrote that oral MRLs were used to evaluate arsenic inhalation exposure. The commenter suggested using an alternative approach to evaluate inhalation exposure.

Response
The analysis and text were changed so that inhalation exposure is evaluated by comparing estimated doses to inhalation-specific toxicity values.

Comment
EPA wrote that the discussion of arsenic in air is unclear. Concerns were expressed that levels exceed Arizona guidelines for air quality.

Response
The discussion of health risks was changed. Environmental levels are compared with ATSDR CVs, and estimated doses are compared with NOAELs and LOAELs from toxicological studies.

Comment
EPA expressed concern about the reference value used by the University of Arizona in their 1999 study of urinary arsenic levels in residents of Hayden and Winkelman.

Response
Language has been added that discusses the limitations of the study. The study, as conducted, was acceptable as a screening tool to see if arsenic urine levels were considered higher than a reference value selected from studies. Other methods might have been more appropriate if the purpose of the study had been to determine what the sources of exposure might be and whether the arsenic found was inorganic in form.

Comment
EPA commented that three of the residents that had recently renovated their homes in the 1999 University of Arizona study had urinary arsenic levels higher than the study reference value. The commenter suggests that this may indicate that there is excessive airborne arsenic levels in the area.

Response
The text has been modified to indicate that no specific source for the exposure was identified. The possibility of paint contributing to exposure is acknowledged, but no follow-up paint testing has occurred to support the theory.

Comment
EPA asked whether the 1995 study of lung cancer mortality found an association between lung cancer and occupational exposures in residents of Hayden and Winkelman.

Response
The study found no association between occupational exposure and lung cancer in Hayden and Winkelman. Positive associations were found in Superior and Miami, Arizona.

Comment
EPA commented that the sample size for the childhood blood testing was small.

Response
While the sample size is small, the participation rate was high. The small sample size reflects a low population of toddlers in the area.

Comment
EPA suggested that the detection of mercury that exceeded the MCL in water be specifically discussed and well owners notified of the testing result.

Response
The average mercury concentration for the public water systems is 1.2 micrograms per liter, which is less than the MCL of 2 micrograms per liter. The data are from water systems regulated by the federal Safe Drinking Water Act. The water company is required by law to notify the public if concentrations exceed the MCL. Although a discussion of the mercury does not appear in this document because levels were below the MCL, ADHS will review groundwater monitoring data EPA and ASARCO might provide to determine if levels of mercury in the drinking water supply could increase over time.

Comment
EPA questioned whether the fact that urinary arsenic levels were not adjusted for creatinine would influence the accuracy of the study.

Response
For screening purposes, the method used was acceptable. For a better indication of arsenic form and actual exposure information, ATSDR, when conducting exposure investigations, does control for creatinine and uses a lower reference value for comparison.

Comment
EPA commented that community concerns that behavioral changes reported by residents suggests that there may be a public health hazard.

Response
At this point in investigations, ADHS did not find completed exposure pathways that might account for behavioral changes. ADHS will continue to evaluate new data, especially data regarding lead and other heavy metal exposure, for possible exposures that might explain behavioral changes.

Comment
EPA suggested that a map be included in the report.

Response
A map has been included in the report.

Comment
EPA noted that an Expanded Site Investigation (ESI) is currently in progress in the area. The commenter suggested that the final report be withheld until after completion of the ESI.

Response
This report includes public health information regarding the Hayden and Winkelman area that will be useful to people with compromised respiratory systems. For that reason, we believe that releasing the report at this time is in the best interest of the community.

We also recognize the importance of evaluating all new data to be able to provide a morecomprehensive public health evaluation of site conditions. For that reason, we will provide ahealth consultation on the new data as soon as possible.

ADEQ Comments

Comment
ADEQ commenter expressed concern about the reference value used by the University of Arizona in their 1999 study of urinary arsenic levels in residents of Hayden and Winkelman.

Response
The selection of the reference value was based on studies that the investigators reviewed when developing protocols for the screening. Had the protocol been more of an exposure investigation rather than a screening, other methods and a lower reference value might have been appropriate.

Comment
The commenter asked why the range of detections are not included in Table 1.

Response
For this public health assessment, mean concentrations of environmental levels were used to select contaminants of concern because mean levels were considered prudent values to use when evaluating exposures.

Comment
The commenter asked whether there are data to support the statement that arsenic in drinking water is naturally occurring.

Response
The source of arsenic might be the result of ASARCO activities or from natural sources. The table has been changed to reflect that information.

Comment
The commenter expressed concern that acute exposures are not evaluated in the report.

Response
The report addresses acute exposures where appropriate. For example, acute exposure to sulfur dioxide for those with compromised respiratory systems poses a public health hazard. That information has been clarified.

Comment
The commenter asked why dermal exposure is not evaluated in the report.

Response
Dermal exposures from contact with soil and water are included in the quantitative dose calculations. The magnitude of exposure to inorganic compounds from contact with soil and water are negligible compared to ingestion and inhalation exposure.

Comment
The commenter asked why the report does not apply acute MRLs rather than chronic MRLs to select chemicals of concern.

Response
The chronic MRL is a more conservative and appropriate reference value to use when evaluating on-going exposures. In the case of sulfur dioxide, acute exposure is more critical to those people with compromised respiratory systems, and the document text has been changed to reflect that issue.

Comment
The commenter noted there is an inconsistency in the levels reported in water in a table and in the text.

Response
The inconsistency has been corrected.

Comment
The commenter noted there is an inconsistency in the levels reported for arsenic in Table 2 for soil and the text.

Response
The inconsistency has been corrected. The average soil concentration for arsenic is 5 mg/kg.

Comment
The commenter noted that the average annual concentrations for arsenic differ from the discussion in the text.

Response
The inconsistency has been corrected, and the text modified to clarify the means by which comparison values are used.

Comment
The commenter noted that recreational exposure to surface water in the Gila River is not evaluated in the report.

Response
The report does not address recreational exposures to contaminants present in the Gila River. A follow-up health consultation for this potential exposure pathway will be considered when the new data are available.

ASARCO Comments

Comment
The commenter corrected the discussion section as it relates to control devices applied at the smelter.

Response
The changes were incorporated into the final report.


CERTIFICATION

This ASARCO Hayden Smelter Site Public Health Assessment was prepared bythe Arizona Department of Health Services under cooperative agreement with theAgency for Toxic Substances and Disease Registry. It is in accordance withapproved methodology and procedures existing at the time the public healthassessment was begun.

Gail D. Godfrey
Technical Project Officer
SPS, SSAB, DHAC, ATSDR


The Division of Health Assessment and Consultation, ATSDR, has reviewedthis public health assessment and concurs with the findings.

Roberta Erlwein
Chief
SPS, SSAB, DHAC, ATSDR


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