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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

ASARCO INCORPORATED (GLOBE PLANT)
DENVER, DENVER COUNTY, COLORADO

APPENDICES

Appendix A -- Figures
Appendix B -- Air Data
Appendix C -- Soil Data
Appendix D -- Exposure Pathways
Appendix E -- Estimated Exposure Doses
Appendix F -- Public Comments

APPENDIX A

FIGURES 1-4

Figure 1. Site Location

Figure 2. Globe Plant Plan

The following figure was not available in electronic format for conversin to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services
Branch, E-56
1600 Clifton Road NE, Atlanta, Georgia 30333

Figure 3.


Figure 4. Priority Sample Population

APPENDIX B

AIR DATA

APPENDIX C

SOIL DATA

APPENDIX D -- EXPOSURE PATHWAYS TABLES

TABLE 7. COMPLETED EXPOSURE PATHWAY
PATHWAY	SOURCE	ENVIRONMENTAL MEDIA	POINT OF EXPOSURE	ROUTE OF EXPOSURE	EXPOSED POPULATION*	TIME
Air	Plant emissions and re-entrained dust	air	ASARCO plant site and residential areas	Inhalation and ingestion	Workers on-site (200) and off-site residents in the area (4878)	past future (dust)
Off-site surface soil	Direct deposits from industrial stack emissions and wind-blown dust	surface soil and wind-blown dust	Residential areas particularly North/North-east and south/south-west of site	Inhalation and incidental ingestion	Residential population north/north-east and south/south-east of the site (1563), emphasis on children under six years of age (578)	past, present and future (until soil remediation)
On-site surface soil	Plant emissions and wind-blown dust	surface soil and wind-blown dust	workers on-site	inhalation and incidental ingestion	on-site workers (unknown)	past present future
On-site indoor air	Industrial metal processes	air	Indoor during active on-site industrial metal processes	Incidental inhalation and ingestion when protective equipment not correctly used	On-site workers (18)	past
Garden vegetables	Air-borne deposits and irrigation	surface soil and water	Home gardens	ingestion	Individual eating home-grown vegetables (100)	past

1.^* Estimated total potentially affected receptor population: 4360; Total children 5 years or younger: 693; Total adults 60 years or older: 461; Total females aged 15-44: 897; Number of Blacks: 399; Number Whites: 1891; Number of American Indians: 61; Number of Asians: 54; Number of Hispanics: 2824; Other: 1646.

2.^* Estimated total receptor population for current and past completed pathways: (a). Current - 1055; (b). past - 3305.

TABLE 8. POTENTIAL EXPOSURE PATHWAY
PATHWAY	SOURCE	ENVIRONMENTAL MEDIA	POINT OF EXPOSURE	ROUTE OF EXPOSURE	EXPOSED POPULATION	TIME
groundwater	neutralization pond, plant facilities, and historic deposits on land	groundwater	private wells for drinking or irrigation (currently none known to exist that are in use in contaminated water plume)	ingestion	no known residential or industrial use at present (population unknown)	past present future
surface water/ sediment	contaminated water and sediment in the Industrial Drainage Ditch and the Farmers and Gardeners Ditch	surface water/sediments	open ditch areas	dermal absorption of water and incidental ingestion	children playing in ditch area (population unknown)	past

APPENDIX E -- ESTIMATED EXPOSURE DOSES

APPENDIX F

PUBLIC COMMENTS

APPENDIX F -- RESPONSE TO PUBLIC COMMENTS

The ASARCO, Inc. (Globe Plant) Public Health Assessment was available for public review and comment from approximately November 18, 1994 to January 6, 1995. The comment period was announced in local newspapers. Copies were made available at the public library, and copies were sent to several individuals and organizations. No comments were received from residents. A summary of comments received from the potentially responsible party (PRP) and our responses are presented in this section. We wish to acknowledge that comments received from the Colorado Department of Health and Environment (CDPHE), and the City and County of Denver were useful and have been used to revise the body of the document where appropriate.

Comment 1	In general, the Globe ambient environmental issues should be viewed as being addressed through process change that began in 1983, and continuing program of emission control leading ultimately to cessation entirely of the cadmium production in 1993. In addition, a July 1993 consent order with the state requires the clean up of residential soils as well as soils, sediments and water on site which address potential off site migration. It appears that the risks the Agency for Toxic Substances and Disease Registry (ATSDR) has characterized are based on data generated prior to the change in plant operations and before the consent order. We are concerned that the ATSDR document will cause concern on the part of the public that the remedy agreed to by the state, and with oversight by the Environmental Protection Agency (EPA) is not sufficiently rigorous. We believe that ATSDR should have taken this opportunity to support what is being done.
Response.	The PHA acknowledges the past and continuing efforts of the PRP to address the environmental issues at the site. Past actions taken by the PRP and others are clearly documented on pages three through seven, in the Summary, Conclusions, and in other sections of the document. Since the purpose of the PHA process is to address the entire exposure issues (accounting for human exposures to contaminants in the past, present, and the future), it is imperative to examine the entire available data. In addition, the document acknowledges past actions by the PRP and others, which have succeeded in reducing or preventing human exposures (as stated several times in the Summary, Environmental Contamination, and Conclusions sections of the document). ATSDR is supportive of all positive actions taken by the PRP to reduce and prevent exposure at the site. ATSDR has given its concurrence for the medical monitoring program, and has prepared a health consultation to assist the state in establishing standards for soil cleanup. ATSDR has not received any comments from residents that might be described as alarming as a result of information contained the PHA.
Comment 2	The Colorado Department of Public Health and Environment's (CDPHE) treatment of the data generated through the 1990 ATSDR sponsored Globeville Childhood Metals Exposure study presents an interesting contrast to the draft public health assessment. The CDPHE May 1994 Superfund Bulletin for Health Professionals states that no elevated cadmium and arsenic levels were found (in the metals study) and 14 of the children (11.3%) tested had blood lead levels equal to or greater than 10 µg/dl, the CDC level of concern. In addition, the average lead levels of Globeville children were similar to the comparison neighborhoods.
Response	The PHA states that 37 (about eight percent) of the young children tested from four neighborhoods in Globeville and control areas have blood lead levels equal to or greater than 10 µg/dl. In addition, the PHA states that a Globeville child is more likely than other children to be in the 5-10 µg/dl range for blood lead levels. The statements will be reworded to reflect the number of study areas, a control area, and to indicate that the source of the lead exposure is unknown. However, the information you quoted from the CDPHE bulletin refers only to one of the study areas and not all four neighborhoods and a control area as discussed in the PHA.
Comment 3	We firmly believe the use of the one excess cancer in a million risk criteria as discussed on page 13 is unrealistic because of the lack of a sound basis for using this level, and because of misunderstandings about one in a million risk (see enclosed article that discuss the myth of 10-6).
Response	The Cancer Risk Evaluation Guides (CREGs) used on page 13 are for screening purposes to determine which contaminants should be looked at more closely in the PHA. The selection of a contaminant for further evaluation does not mean that either exposure to the contaminant or adverse health effects has occurred or will occur. However, you are correct that there is some uncertainty associated with using the risk level of 10-6 to describe community exposure at hazardous waste sites. Because of this uncertainty the risk of 10-6 should not be consistently applied in every exposure situation. Although ATSDR recognizes the utility of numerical risk estimates in risk analyses, the Agency considers these estimates in the context of the variables and assumptions involved in their derivation and in the broader context of biomedical opinion, host factors, and actual exposure conditions. For example, ATSDR considers cancer exposure levels (as determined in epidemiological studies), the type and magnitude of contaminant levels as well as the route of exposure. These considerations influenced the cancer risks described in the Public Health Implications section of the PHA.
Comment 4	It should be clear that the exacerbation of childhood respiratory disease concerns as discussed on page 45 are far more likely to be caused by the Denver area general air quality rather than the small amounts of cadmium, tellurium, and antimony as alleged on page 41 in answer to a question regarding respiratory problems. Is it not also true that cadmium, tellurium, and antimony exposures that may have led to respiratory problems in humans were in an occupational setting?
Response	The PHA acknowledges that the Total Suspended Particulate (TSP) problems in the Denver area are due in part to other industries in the area and the main freeway systems. The TSP can exacerbate the respiratory conditions that are commonly observed in the area. It is clearly stated in the Summary, Environmental Contamination, Community Health Concerns Evaluation, and Conclusions sections, that the city-wide problem of TSP levels contributes to the occurrence of respiratory conditions.
Comment 5	If the document truly is a public health assessment, why are continued references made to historical worker exposures and violations (examples are found in paragraph two of the Summary, pages 17 and 18, and paragraph one of the Conclusion).
Response	As stated in the response to your first comment, the purpose of the PHA process is to address indicated exposure scenarios, taking into consideration workers as well as nearby residents. It is necessary to examine all information pertaining to exposure to contaminants at the site.
Comment 6	On page 34, a reference is made to Globe workers eating Globeville grown vegetables. ASARCO knew of only one Globe plant employee that lives in Globeville, and that employee does not have a garden.
Response	That reference in the PHA is made in regard to any past PRP workers who may fall into that exposure category. The document will be changed to reflect the new information.
Comment 7	It should be noted that EPA has not listed Globe on the NPL (page 3).
Response	The statement on page three indicates that the site is proposed for listing on the NPL. The document has not been changed.
Comment 8	The results of the 1982 FIT and EPA NEIC investigations did not demonstrate either air quality or groundwater problems.
Response	The document has been reworded to indicate that the study focused on those contaminants listed on page 4 in the PHA.
Comment 9	On page 6, state year of site visit; and 2nd last line - Globe does not produce thallium.
Response	The document has been corrected.
Comment 10	While ATSDR may have heard some concerns (last two lines on page 8), the enclosed news article from LA VOZ suggests community support for the clean up process.
Response	An exposure study by the Colorado Department of Health indicates that there is concern among some residents about potential health threats posed by the ASARCO plant. However, you are correct that the cleanup process is aimed at addressing this potential threat.
Comment 11	On page 24 paragraph D - reference is made to buildings no longer being used becoming a safety and chemical hazard for the public. However, it should be noted that the site is completely fenced and public access strictly limited.
Response	The PHA acknowledges on pages 7 and 24 that the site is fenced. However, we have altered the last sentence of paragraph D, page 24, to clarify that the unused buildings could only become public hazards if access to the site does not continue to be strictly limited.
Comment 12	On page 26, it should be noted that the PRP consent order requires annual water use surveys to preclude future use of shallow groundwater.
Response	The document will be changed to reflect this comment.
Comment 13	On page 32, the PRP is concerned about unnecessary speculation with regard to arsenic exposure and skin pigmentation.
Response	Epidemiological studies in humans suggest that residents exposed to levels similar to those reported in the PHA experienced hyperkeratosis. The PHA only suggested that children exposed to the levels of arsenic reported in this document might experience similar health effects.
Comment 14	On page 41, the PRP is concerned that ATSDR has not stated that soils below the surface rapidly fall in metal concentration.
Response	The PHA states that contaminant concentrations do decrease with depth. However, the document will be revised to reflect that soils below the surface rapidly fall in metal concentration.

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Agency for Toxic Substances and Disease Registry, 1825 Century Blvd, Atlanta, GA 30345
Contact CDC: 800-232-4636 / TTY: 888-232-6348 

Department of Health and Human Services