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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

CORNHUSKER ARMY AMMUNITION PLANT
GRAND ISLAND, HALL COUNTY, NEBRASKA

APPENDIX A: DEMOGRAPHIC INFORMATION

Nebraska:

1980 Total Population: 1,569,825

Percent Black: 3.1%
Percent Spanish Origin: 1.8%
Percent less than 18 years old: 28.5%
Percent greater than 6 years old: 13.1%

1990 Total Population: 1,578,385

Hall County:

1980 Total Population: 47,690

Percent Black: 0.3%
Percent Spanish Origin: 2.8%
Percent less than 18 years old: 30.1%
Percent Greater than 6 years old: 12.5%

1990 Total Population: 48,925

Grand Island:

1980 Total Population: 33,180

Pecent White: 97.8% (32,457 persons)
Percent Black: 0.3% (102 persons)
Percent Spanish Origin: 3.2% (1,066 persons)
Percent less than 18 years old: 27.8%
Percent greater than 6 years old: 14.5%

1980 Population by Age Groups:

Less than 5 years: 2,664
5 to 9 years: 2,539
10 to 14 years: 2,428
15 to 19 years: 2,670
20 to 24 years: 3,130
25 to 29 years: 2,960
30 to 34 years: 2,548
3 to 39 years: 1,750
40 to 44 years: 1,420
45 to 49 years: 1,437
50 to 54 years: 1,640
55 to 59 years: 1,665
60 to 64 years: 1,511
Greater than 64 years: 4,818

1990 Total Population: 39,386

Grand Island Employment and Income:

1980 Occupations of Employed Persons:

Employed persons 16 years and over: 16,138
Managerial & Professional 3,449
Technical, Sales, & Administrative Support: 4,797
Service Occupations: 2,620
Farming, Forestry, & Fishing: 248
Precision Production, Craft, & Repair: 2,205
Operators, Fabricators, & Laborers: 2,819

1980 Persons with Work Disability:

Males aged 16 to 64 years: 9,674
Number with Work Disability: 885

Females aged 16 to 64 years: 10,350
Number with Work Disability: 749

1980 Income in Grand Island:

Per Capita Income for Individuals: $7,291
Percent below Poverty Level: 6.9%

Cornhusker Army Ammunition Plant and City of Grand Island. Shaded area denotes source of census information demographic data

Demographic Information for Populations Around Cornhusker Army Ammunition Plant

APPENDIX B: HEALTH STATISTICS

Birth Statistics for the Area:

Death Statistics for the Area:

1988 Causes of Death

Rates are age adjusted per 100,000 population

1989 Causes of Death

Rates are Age-adjusted per 100,000 population

Nebraska Cancer Registry, 1988
Malignant Cases only

* Crude Rates per 1000 population

APPENDIX C: COMMENTS ON CORNHUSKER ARMY AMMUNITION PLANT PUBLIC HEALTH ASSESSMENT

The following responses were received during the public comment period. This list of comments does not include editorial comments concerning word spellings, sentence syntax, etc. It does not include comments on accuracy of stated facts. If the accuracy of a statement was questioned, the statement was verified or corrected. The portions of the comments below that are in parentheses were paraphrased by ATSDR for brevity or clarity. If the same comments were received from more than one source, only one comment and response is listed.

Comment 1: The value of child body weight 10 Kg was used in Table 3 concerning soil contamination. According to EPA standard default exposure factors, child body weight should be 15 Kg for age 0 to 6 year group.

Response to Comment 1: ATSDR uses 10 Kg as a child body weight to calculate comparison values. Using this lower weight results in a more conservative comparison value for protection of public health.

Comment 2: Page 16, Paragraph 2. The paragraph is very biased. Grab samples are appropriate when used in conjunction with aerial photography, ground truthing, surveying of discharge pipes and waste water. Many of the grabs were taken at key locations that would provide the worst case contamination, such as discharge ditches. If contamination is found in the ditch then further areal delineation would occur.

Response to Comment 2: The first sentence of the section on page 15 states: The stated purpose of previous sampling, including samples taken in Fall 1990, was not to define the extent of contamination, but to delineate areas requiring further study (1). The paragraph on sampling is presented to simply describe different types of sampling that have occurred. The next paragraph describes the approach that will follow after the initial sampling. That sampling provides more extensive determinations of contamination and uses the earlier sampling as a starting point.

Comment 3: The various target excavation levels were set for the explosives. The reference should also be provided on these target levels.

Response to Comment 3: The reference was listed later in the paragraph. It has now been added after the sentence in question.

Comment 4: Lead contamination has been found in the North Magazine Area. Consider further sampling to detect lead contamination in on-post soil.

Response to Comment 4: The phase one field-screening analysis will include 2,4,6 TNT, cadmium, chromium, and lead. This is mentioned in the Proposed Analytes During RI/FS section on page 18.

Comment 5: Pages 18, 19, and 48. At this point in time it is not technically feasible to analyze samples for many of the breakdown products of TNT and RDX. This is due primarily to the fact that most of those analytes can only be detected by laboratory research methods which are not yet commercially available. In those cases where the products will be detected via the commercial methods, the product concentrations will be reported by the Army. For example, the TNT breakdown products 2,4,6-trinitrobenzaldehyde, 3,5-dinitroaniline, and 4,6-dinitrobenzoic acid can and will be reported as tentatively identified compounds if their concentration is at least 10% higher than the equipment calibration standards.

There are other compounds that can be detected commercially by specific laboratories, but which weren't included in the workplans submitted for ATSDR review prior to field work. Examples would include hydrazine, formaldehyde, methanol, and tetranitromethane. However the need for such testing must be identified prior to the implementation of field work so that the appropriate sampling preservation, and laboratory arrangements can be made. If ATSDR has some reason to believe these compounds may pose a potentially significant health threat at the site, we can attempt to ensure that these compounds are addressed in the next phase of the investigation. Sampling for many of the TNT and RDX breakdown products can only be accomplished at significant expense and effort, and with questionable results. In that light, we do have questions regarding how any information which might be obtained by sampling for TNT and RDX breakdown products will be evaluated. Based on our understanding, there is no current health effects information which exists on those breakdown products. If ATSDR is aware of such information, we would appreciate being informed of such so that we can take that information into account during our evaluation of future workplans for this and other sites.

Response to Comment 5: Choosing specific chemicals to add to an analyte list based on potential health effects is difficult when little toxicological information is available. Little information is available about health effects of long term exposure to low concentrations of even the primary compounds. Additionally, predictions are difficult to make about relative concentrations of the breakdown products possibly remaining in the groundwater. Because, in general, health effects to various compounds are related to some extent to concentrations, it may be of value to obtain information about the relative amounts of some of the breakdown products in the groundwater. As mentioned in Comment 5, several of the chemicals not listed on the proposed analyte list will be detected during the routine analysis if their concentrations are significant. That information has been added to the text of the public health assessment. Of the remaining chemicals that can be analyzed for commercially but were not proposed for analysis, consideration should be given to sampling for hydrazine and 1,1-dimethylnitrosamine. Literature is available on the possible adverse health effects of these compounds. References have been added to the text of the public health assessment.

Defining the extent of contamination of groundwater with specific chemicals will be of value in designing health studies to determine whether or not adverse health effects have occurred in the population because of past exposure to the contaminants. The most important aspects of the investigations occuring at CAAP for the protection of public health are activities aimed at identifying the potential for exposure to contaminants in drinking water and prevention of that exposure. That process is being carried out in ongoing RI/FS investigations.

Comment 6: Page 22, Paragraph 2, Subsection 4. It should be noted that the reason well construction data is not available is that the high number of wells that the Army has been monitoring are domestic irrigation and drinking water wells. These wells were not installed by the Army and the construction data is not normally retained by the owner.

Response to Comment 6: This has been added.

Comment 7: The ATSDR defines the completed exposure pathways as a situation in which five elements must be present to provide evidence that exposure to a contaminant has occurred, is occurring, or will occur. A potential pathway is defined as a situation in which at least one of the five elements is missing, but could exist. All potential pathways presented in Table 9 on page 34 are not missing any of the five elements. In addition, the on-site surface soil pathway could also be a completed pathway because exposure to a contaminant soil has occurred, is occurring, or will occur.

Response to Comment 7. The most important completed pathway of public health interest at CAAP is the private well pathway described in Table 8. Sampling of private wells indicated the presence of contaminants in drinking water. Exposure through the route of ingestion may have occurred for several years. Current environmental data also indicates the presence of contaminants in groundwater. Some people currently are using private wells, and as the contaminated plume extends, the exposure pathway would also be complete.

Table 9 lists potential pathways. For an ATSDR exposure pathway to be considered complete, information must be available for each of the five elements of the pathway. Substantial environmental information is not available for Sediment, Ambient Air and Food Chain pathways. Although some sampling information is available for sediment, additional data is needed to substantiate the extent of contamination, especially off post in areas where people might be exposed. No sampling data was available for ambient air. In addition, no information was available about the relation between the past open burning and the location of the nearest residences at that time. Limited sampling was available for vegetables in the food chain pathway, however no contamination was found. On-Site Surface Soil is considered presently as a potential pathway. Some sampling data is available from many different sites on the installation. If CAAP were an active installation with workers and visitors entering the installation daily, some of the sites might be considered as sources for complete exposure pathways. However, due to the isolated status of the installation, people do not come in contact with the contaminated soil for extended (if any) time periods to substantiate a completed exposure pathway. Presently the exposed population element of the pathway is missing. On the other hand, the soils represent a very important potential pathway. Further investigation is ongoing in the RI/FS. This additional information must be considered with respect to the future land use of the CAAP. If changes in activities such as commercial or residential use of the land are proposed, then the potential for public health concern will increase. ATSDR will reevaluate the information with regard to soil pathways at that time.

Comment 8: "Recommendations" Number 1, regarding public access to magazines would require Headquarters, U.S. Army Armament, Munitions and Chemical Command (AMCCOM) to provide physical security support, since the Plant does not have gate guards or patrols during business hours.

Response to Comment 8: Because of the potential for ingestion of contaminated soil, ATSDR recommends limiting the public's access (especially children) to the areas (magazine) until the extent of contamination is further characterized during the RI/FS. Limiting access to children can be performed by a variety of means. If people were reminded to not bring children to the area, most would comply and thus access of children would be limited. Furthermore, the Army is continuing to reduce the number of storage magazines that are leased for public use.

Comment 9: "Recommendations" Number 2, second paragraph; soil contamination concentration will impact the extensive leasing of agricultural land on CAAP. Any changes in leases would require a careful approach by the Army, due to the legal, economic and public relations factors involved.

Comment 10: The discontinuance of on-site crop irrigation would have a severe impact on agricultural leases.

Response to Comments 9 and 10: Recommendation number 2 in the second paragraph is directed at further evaluation of contamination levels in soils at specific sites where people may be exposed if the land use changes. If new public use of lands were proposed, further evaluation would be necessary. This does not refer to major changes in agricultural land use. CAAP has recently discontinued agricultural leases in areas of suspected high explosives contamination of the soil. Other areas, however may be using irrigation water that has high levels of explosives. Studies as part of the RI/FS are underway to evaluate the potential of these concentrations of explosives to be incorporated into the crops. In addition, use of irrigation water in 1992 has been low. This also reduces the potential of contaminant uptake by crops. Because the use of irrigation water has been low, crop uptake studies have been postponed to facilitate a study that will allow a more valid estimate of contamination uptake by crops irrigated with contaminated water. These studies will also bear on the questions of private well water usage for vegetable gardens.

Comment 11: Since residential gardens, as well as soil from yards (may have been) irrigated with RDX and TNT-contaminated water, vegetable sampling from the gardens should also be tested for TNT. Although no RDX was found in concentrations greater than the detection limits of the assays, TNT may be found above the detection limit. Plants may uptake more TNT than RDX from soil and irrigated water.

Comment 12: The level of 0.19 ppm in vegetables was developed as the health risk level by using EPA guidances. Is this level for RDX only in the vegetables? Are there any health risk levels of other explosives in the vegetables?

Response to Comments 11 and 12: Measurement of RDX and TNT in plant tissues is not a routine, commercially available laboratory assay. To simplify the evaluation, as well as to speed the initial sampling in vegetable gardens, RDX was used as the indicator contaminant. This choice is supported by the fact that, in general, TNT levels in the groundwater were lower than those of RDX, and that laboratory plant studies showed that TNT was more likely to remain in the roots of the plants that was RDX. RDX was also shown more likely to remain intact and not be metabolically broken down as much as TNT (see references 22 and 23).

Comment 13: The detection limits of RDX, TNT, and HMX concentrations in soil were presented in this section (section B, page 20). Are these limits background levels? Was EPA guidance used to develop these detected limits?

Response to Comment 13: The referenced detection limits are those for EPA approved methodologies for measuring those contaminants in soil. The detection limits are below ATSDR comparison levels used to determine concentrations of contaminants that may cause adverse health effects.

Comment 14: Page 24, Paragraph 2. The discussion of the regional nitrate levels did not reference the document "Nitrogen and Irrigation Management, Hall County Water Quality Special Report", dated February 1984. This report summarized that 67-79 percent of the Hall County wells exceeded 10 ppm for nitrates, which would seem to support the regional nitrate concerns.

Response to Comment 14: The report has been reviewed and included in the discussion.

Comment 15: No references were made (page 2, page 20, page 31, and page 46) to the report entitled "Calculation of TNT and RDX Concentration Limits for Feedlot Water Supplies" dated August 1984. The recommendation that the feedlot use city water should not be based solely on the idea that city water is available and adjacent to the feedlots.

Response to Comment 15: The feedlot study was discussed and referenced in the public health assessment in the Public Health concerns section. That study is an article written to calculate TNT and RDX concentration limits for feedlot water supplies. It uses risk assessment methods to determine safe water contaminant levels for the health of the cattle as well as to estimate safe water contaminant levels that would not result in accumulation of TNT and RDX in meat of the cattle. To make calculations of that type, assumptions must be made. Some assumptions must estimate mathematical safety factors to be included which account for differences in duration of exposure, the species of animal for which experimental data exists, physiologic processes of contaminant concentrations in different animal tissues and others. Most of the biological data from which these assumptions are made come from a minimum number of studies in animal species other than cattle. Thus, the necessary assumptions have room for error.

Calculations using those studies do indeed suggest that TNT and RDX are not likely to accumulate in meat of cattle (drinking concentrations of explosives found in the groundwater around CAAP) to the extent that adverse health effects in humans consuming that meat would result. Because of the previously mentioned assumptions that must be made to make conclusions based on such calculations, other ways to confirm the safety of meat for consumption may be more reliable. The recommendation was made to use the city water supply for watering cattle until suitable animal studies (sampling of feedlot cattle or other experimental cattle studies) could be carried out to answer the questions. This conservative approach will give direct information to be certain that explosives are not detectable at concentrations of concern in meat consumed by the public.

Comment 16: We moved out in the afflicted area 6 years ago when the cleanup was all taken care of. We have had our water checked numerous times and for some unknown reason they tell us everything is fine. I question the validity of the Army and the testing facility. I know that they are drilling new test sites around our area which leads me to believe that there is more to the story than we are being told.

Response to Comment 16: The initial cleanup of CAAP included removal of explosives-contaminated soil that was a source for contamination of groundwater. Further sampling of both soil and groundwater is being carried out during the current Remedial Investigation phase of the work at CAAP. This includes drilling new monitoring wells in the area to determine the width and depth of the contaminated area in the groundwater. This will lead to a decision about the best means to clean up the contamination. All testing during the investigation is performed under specific laboratory criteria. Laboratory results are reviewed by both the Army and EPA to ensure that the analyses were performed properly. As an independent agency, ATSDR also reviews laboratory quality control information during preparation of public health assessments.

Comment 17: I question why there has not been a health study on humans, animals and plants. We hear that there are going to be things done but that is as far as it goes.

Response to Comment 17: Design of a health study that will address potential health effects resulting from exposure to contaminants in the groundwater around CAAP requires information about potential routes of exposure of the population to the contaminants. Continuing groundwater sampling studies are defining the extent of groundwater contamination. In addition, sampling studies have been carried out on vegetables from gardens watered with contaminated water. No contaminants were found. That represented a possible point of exposure to people.

The ATSDR Division of Health Studies will perform health studies in the community surrounding CAAP. This is listed under Actions Planned in the Public Health Actions section of this public health assessment. A preliminary site visit for planning purposes to the area is scheduled for October, 1992.

Comment 18: I have concerns about our livestock, our water tanks have a red oily film when they set for a few days and inside our house we have had a lot of problems with our well, hot water heater, water softener, reversed osmosis system and dishwasher which are all related to water.

Response to Comment 18: The physical appearance of water can be related to a number of different causes. It can be influenced by bacterial, mineral or chemical contents. The only way to assess the potential chemical content of water is to analyze the water for specific chemicals.

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