Remediation personnel conducting on-post soil cleanup activities stand the greatest risk of potential exposure. However, previous remediation efforts and the planned final cleanup activities conducted under the Offpost and Onpost RODs (HLA, 1995; Foster Wheeler, 1996) have been and will continue to be governed by comprehensive site safety plans. Those safety plans and the activity coordination measures already in use are designed to ensure that all remediation activities are conducted so that the health and well being of workers, site-visitors, and residents of nearby communities is not jeopardized.

Environmental data for surface soils show that the highest chemical concentrations cluster in the center of the Arsenal and decrease in a gradient fashion to levels of insignificant health concentrations at the boundaries of RMA. Therefore, a future soil pathway is not expected to extend to off-site residents (EBASCO, 1992). Although it is feasible that during soil excavation, onpost transportation, and landfilling activities soil could be windblown engineering measures will be taken to minimize that possibility and project supervision and environmental monitoring will further assure that the accidental release of contaminants is minimized or eliminated.

The public health of the nearby neighborhoods will be further safeguarded by the activities undertaken under Component 18 of the Conceptual Agreement (Colorado, 1995). That component, incorporated in the RODs, provides that a plan will be developed to monitor any off-post impacts on human health due to the remediation and to provide mechanisms for evaluation of human health on an individual and community basis, until such time as the soil remedy is complete.

At present, visitors to the refuge are denied access to areas containing soils that are contaminated at levels that could result in adverse health effects (EPA, 1989a). Final site cleanup activities will remove the potential for exposure of refuge visitors to contaminants at levels that would cause adverse health effects. During the site cleanup activities there may be times that refuge visitation levels or available areas may be restricted because of activity coordination or safety reasons.

What are the possible off-post health effects from the Submerged Quench Incinerator (SQI) emissions?

Basin F liquid was destroyed on site where it was produced. The incinerator posed no significant risk to nearby residents. The incinerator startup began in March 1993 and all incineration activities were completed in 1995. The incinerator treated the liquid wastes more safely and efficiently than predicted. Prior to full operation, the incinerator underwent testing to verify the system design. During testing, representatives of the Arsenal staff, the SQI operations staff, its transportation facilities, and the RMA Fire Department participated in a successful emergency drill. A laboratory was established with equipment and staff for analyzing brine samples and scrubber water from the incinerator's quench and air pollution control equipment throughout SQI operations. Performance testing of stack continuous emissions monitoring and air pollution control equipment began before the startup of SQI. Automatic emergency shutdown controls tested under operating conditions functioned properly, operating systems performed as designed, and equipment was adjusted to meet operating standards.

The Final Human Health Risk Assessment was completed in March 1994. The multipathway human health risk assessment, based on the SQI emission rates measured during the trial burn of Basin F liquid, documented that the facility did not pose unacceptable carcinogenic risk or non-carcinogenic health effects to sensitive populations (Resident-A, Resident-B, Farmer, and Worker), as defined by EPA guidance (EPA, 1989b) and the Final Decision Document (Woodward-Clyde, 1990b). Refer to The Final Human Health Risk Assessment for detailed descriptions of these populations. ATSDR reviewed the SQI emissions data and the results of ambient air monitoring and agreed that the operation of SQI was not of public health concern to off-post residents or people who work or visit RMA (Weston, 1994, p. 11-10, 11-11).

Will RMA remediation activities result in adverse health effects from diminished air quality in the Montbello neighborhood, directly south of RMA?

Air monitoring at RMA is an ongoing function of the Comprehensive Monitoring Program (CMP). The CMP has the following objectives: 1) identify and evaluate potential air quality health hazards; 2) monitor progress made in removing air contaminants from previous RMA activities; 3) provide baseline data to evaluate the progress that will be made in future remedial activities; and 4) develop real-time guidelines and standards with which to evaluate the effects of ongoing remedial actions.

To achieve those objectives, the air monitoring element of the CMP utilizes a combination of about 12 fixed-point RMA interior and perimeter air monitoring stations, strategically placed with respect to possible contamination sources and prevailing wind directions, and about 24 portable air monitoring stations. Those 24 portable monitoring stations detect and monitor possible effects relating to ongoing remedial actions or other activities of special concern (Stollar, 1991a, p. 1).

In addition, the data and information compiled from the CMP provides a valuable historical baseline from which future activities can be planned, mitigation measures identified, and potential future effects forecast and measured.

The Medical Monitoring Program established by the Conceptual Agreement (Colorado, 1995) and the RODs (HLA, 1995; Foster Wheeler, 1996) will evaluate the environmental monitoring needs (including air monitoring) during the final site cleanup and will recommend the adoption of an air monitoring plan designed to help ensure the protection of the public health of the nearby neighborhoods.

The data compiled thus far by the CMP indicate that the concentration of airborne contaminants generated by previous RMA remediation activities declined rapidly with distance from the source. At the RMA boundaries, the measured concentrations of total suspended particulate (TSP), metals, and volatile and semi-volatile organic compounds (VOCs, SVOCs) had declined to levels below health concern (Stollar, 1991a, p. 11-14). Monitoring data further indicate that the air quality of the Arsenal and areas such as Montbello is affected by particulate, VOCs, and SVOCs resulting from the industrial activity and vehicle use within the Denver Metropolitan Area. From windrose data, it appears that the wind blows primarily from RMA to the north and northeast, away from Montbello.

Evaluation of the human health risk associated with remediation activities, such as SQI, and future actions have been and will be completed before the actions are implemented. Actions that may potentially affect the Montbello Area and other off-post areas will be carefully monitored to assure that actual air contamination levels do not exceed the levels judged to be protective of public health. The Conceptual Agreement (Colorado, 1995) specifically provides that technologies to control emissions and odors from material handling operations will be determined in the design of the remediation actions and implemented, as necessary, throughout the remediation phase.

Was SQI used for non-RMA hazardous wastes?

SQI was approved by EPA and the state of Colorado only for incineration of Basin F associated wastes. Non-Basin F wastes were not approved for this incinerator. The SQI incinerated the organics in the 10.5 million gallons of liquid that was stored in three steel tanks and a covered, double-lined pond filled with wastes formerly disposed of in Basin F (Weston, 1994). SQI successfully completed it function in 1995 and was dismantled.

Specific Health Concerns:

Introduction

In this portion of the assessment, specific health concerns are addressed in the context of exposure pathways to RMA and non-RMA contaminants, known risk factors related to the development of specific health conditions or diseases, previous health studies and investigations conducted in the communities adjacent to RMA, and additional information (such as, medical history, occupation, and location of residence) gathered from discussions with residents who attended the Public Availability Sessions and had health concerns.

The majority of concerns expressed by residents near RMA were for whether specific health conditions or diseases, such as cancers, occur at excess rates in the communities adjacent to RMA. ATSDR attempted to gather as much information as possible from those who had specific health concerns and attended the Sessions, since a variety of health conditions or diseases may share similar risk factors and certain risk factors may contribute more heavily to the occurrence of a particular disease or condition. For instance, when residents near RMA expressed specific health concerns, ATSDR inquired about such information as personal and family medical history, occupation, smoking status, place (s) and duration of residence, private well use and duration, and other exposure factors that might be related to the development of cancer or other health conditions and diseases.

In addition to the information and responses appearing here, Appendix C has additional discussion on the risk factors and a summary of important health information on each of these specific health conditions for people who may want to know more about these conditions or places to contact locally for more information. Also, if people reading this report suspect or have a concern about cancer or some other type of health condition, they should contact their personal physician or a local physician in their community.

Is there an excess of lupus in the Montbello community?

Unfortunately, there are no local or national databases that would allow us to determine whether an excess of lupus exists in the Montbello community. However, the following information specific to the causes of lupus and actions taken to address this concern are provided below.

Mortality rates for lupus exist for the nation, state and counties of Colorado, but the information is not collected such that Montbello is broken down separately from Denver County rates (Wonder, 1991). Furthermore, the mortality rates available only show the number of deaths attributed to lupus. Unlike incidence or prevalence rates, mortality rates do not have information that would allow us to address whether an excess exists for those who are currently diagnosed with lupus. Incidence rates or prevalence rates are needed for the Montbello area or that general area in order for us to address this concern.

The Lupus Foundation of Colorado was consulted about whether a local database containing incidence rates for lupus existed for communities near Denver. They indicated that only national incidence rates are available for the U.S. Individual state information is not available (ATSDR, 1994e).

Local physicians were also contacted for their personal impressions as to whether they were aware of concerns for an excess of lupus cases or personally had seen more cases of lupus than normally observed. None of the doctors in the Montbello area had heard of or seen an usually large number of cases of lupus (ATSDR, 1993c and 1993d).

In addition to contacting the local lupus chapter and physicians in the Montbello area, the possibility for exposure to RMA contaminants and the causes of lupus were investigated. Windblown contaminants have been occasionally deposited on the surface soils of the southern portion of RMA near the Montbello community. However, the environmental data show that the soil contamination on RMA decreases progressively from the location of the RMA sources to the southern boundary of RMA. The very low levels of surface soil contaminants that have been detected in the southern part of RMA are not expected to harm people's health. Because the groundwater contaminants have migrated to the north and northwest, residents in the Montbello area have not been exposed to those contaminants through drinking water. Because exposure to RMA contaminants at levels of public health concern has not occurred to Montbello residents, it is unlikely that cases of lupus in the Montbello community are related to RMA contaminants.

Lupus is more prevalent among blacks, especially black women. According to the demographic makeup of Montbello, blacks comprise almost 60% of Montbello's population (see Table 3). Therefore, it is likely that more cases of lupus would be observed in the Montbello area as compared to the surrounding communities near RMA, because the percentage of blacks in Montbello is considerably higher than in surrounding communities.

We do not know what causes lupus. Some evidence supports a genetic link; however, there is no proof that those with the genetic predisposition will develop lupus. Certain influences, including viral infections, exposure to ultraviolet light, certain drugs (further discussed in Appendix C), chemicals, and other stressors seem to trigger the onset of a flareup of symptoms (Lupus Foundation of America, Inc., 1992, p. 1).

There are two main types of lupus: systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE). Patients may have one or both (Lupus Foundation of America, Inc., 1992, p. 1). In lupus, the immune system forms antibodies to the body's own tissue and attacks the organs and body systems. Effects on joints, lymph glands, heart and lungs, kidneys, abdominal organs, and the brain are well documented (Aladjem, 1992, p. 1). Clinical signs and symptoms can be characterized as general, non-specific illness (systemic symptoms include fatigue, malaise, fever, anorexia, weight loss, and nausea); non-life-threatening clinical manifestations (skin rashes, mouth ulcers, arthritis, and serositis); and potentially serious involvement of major organs: heart, lungs, kidneys, or the brain (Aladjem, 1992, p. 2-3). Serositis is an inflammation of the membranes that line the lungs, heart, and abdomen.

Refer to Appendix C for more information on lupus.

Is there an excess of cancer in the Montbello neighborhood?

The Colorado Department of Public Health & Environment (CDPHE) used data from the Colorado Cancer Registry to perform a review of cancer incidence rates for the Montbello area from 1985 to 1993 (CDPHE, 1993b). The types of cancers and the methods of analysis were consistent with those presented in the cancer incidence study for the Northeast Denver Metro area that CDPHE also conducted and released in August 1993. No statistically significant rates of cancer were observed for the Montbello area as compared to the 1986-1988 race-, sex-, and age-specific rates for the Denver Metropolitan Area.

Is it safe to eat vegetables grown in gardens irrigated by private well water in Commerce City or north of RMA?

Municipal water supply systems are subject to rigorous periodic testing requirements to ensure the safety of the water of human consumption and uses such as irrigation of garden produce.

In order to assure the safety of the private well water for garden produce irrigation, the Army gathered new data in 1995 on DIMP concentrations in vegetables grown in the area. That data strongly supports the findings of the previously completed Endangerment Assessment (HLA, 1992b) and indicates that it is safe to eat vegetables irrigated with well water drawn from the Alluvial Aquifer north of RMA. The information that supports this conclusion is given below.

In 1990, a wide variety of vegetables and raw milk from farms and gardens offpost to the far north and northeast were collected by CDPHE and sampled for DIMP, which was not detected. Raw milk, cabbage, corn, onions, romaine lettuce, red leaf lettuce, green curly leaf lettuce, broccoli, turnips and greens, mustard greens, bok choy, and black-eyed peas were collected. Soil and groundwater sampling were not conducted in conjunction with this study. Therefore, even though DIMP was not detected in the vegetables, it was not certain that samples were obtained from an area that contained enough DIMP in soils or groundwater to be expected to be taken up into the vegetables.

As reported in the Offpost RI Addendum in 1992, cattle, chicken, several different fish species, and milk were collected and analyzed for a broad range of target analytes (see Table 13). None were detected at levels of public health concern (HLA, 1992a).

The Endangerment Assessment prepared for the Offpost Operable Unit (HLA, 1992b) evaluated the risk associated with the consumption of vegetables irrigated with Offpost groundwater and grown in Offpost soils. That assessment concluded that consumption of those vegetables would not result in any adverse health effects. Subsequent to the completion of the Endangerment Assessment data has been developed on DIMP contaminant levels in garden vegetables grown in the area of potential concern. The Army asked Tri-County Health Department to obtain samples of garden vegetables from Offpost sites to determine what concentrations of DIMP, if any, are in Offpost vegetables. The samples were collected from the garden of private residence north of RMA on October 12, 1995 and from two large vegetable farms on November 10, 1995. The private garden was selected by the Army because it is irrigated only with water from well 1178B which has higher concentrations of DIMP remaining than any other Offpost area well. The concentration of DIMP in that well have ranged from about 150 to 950 ppb. The commercial farms were selected because they utilize a combination of groundwater (DIMP <20 ppb) and surface water (uncontaminated by DIMP).

The vegetables were analyzed using a recently developed method to determine DIMP concentrations in vegetables (detection limit, 20 ppb). The concentrations of DIMP detected in the private garden cucumbers ranged from 340 to 920 ppb and the tomatoes from that garden contained DIMP at an unquantifiable level below the detection limit. The vegetable samples (corn, onion, chile pepper) taken from the large vegetable farms contained no detectable DIMP.

Comparison of this 1995 garden vegetable data with the calculation of potential risk given in the Offpost Endangerment Assessment (HLA, 1992b) indicates that even under a "worst-case " exposure scenario, the consumption of vegetables irrigated with DIMP-contaminated groundwater is not expected to result in adverse health effects. This conclusion is based upon the estimation of the potential DIMP concentration in lettuce. Lettuce was selected to evaluate the potential risk associated with consumption of Offpost-grown vegetables because studies have shown that plant leaves have the highest potential to accumulate DIMP.

Are there elevated levels of learning disabilities in the children residing in Commerce City, near the western boundary of RMA?

To address this concern, ATSDR contacted the Department of Education, Colorado Department of Health, to determine whether any local databases existed on rates of learning disabilities for communities surrounding RMA, particularly Commerce City (ATSDR, 1994a and 1994b). ATSDR learned that while they establish education guidelines for the state, they were unaware of any database that would contain the type of information requested. There are nine learning disabilities that have been defined by the state, but no information exists on the rates of those disabilities.

As of June 11, 1992, the Colorado Department of Education issued the Rules for Administration of the Exceptional Children's Educational Act to establish special education guidelines for the state. There are nine learning disabilities defined according to state guidelines: dyslexia; hearing impaired; vision impaired; emotionally impaired; physically impaired; speech and language impaired; emotionally disturbed; mentally impaired; and multiply impaired, a term used to describe a person with more than one of these disabilities.

Parents concerned about learning disabilities should contact their local school boards or the Colorado Department of Education for information about testing and what type of help exists locally for children with learning disabilities.

Has Diabetes been linked to the chemicals detected in private wells north, northwest, or west of RMA? Could it be linked to prenatal exposure to those chemicals?

The individual who voiced this concern resided a little more than 2 miles north of the northwesternmost boundary of RMA. His family lived at this residence in Henderson from 1979 until 1985, when they moved away. In their family, there are five children, and one child has been diagnosed with insulin-dependent diabetes, or Type I diabetes mellitus. The family first lived at this residence in Henderson in 1979; the son was born during January of 1983, and they began to suspect diabetes in 1985 when he was 2½ years old. This individual asked whether diabetes has ever been associated with prenatal exposure to DIMP in his private well. He reported that a maximum level of 425 ppb DIMP had been previously detected in the water from his private well. This individual shared water sampling data with ATSDR and his address and designated well number such that the well could be investigated by ATSDR staff.

This individual's private well taps into the Arapahoe, one of the deeper aquifers. The drinking water well was used for drinking, bathing, showering, gardening, and other household uses. At the time of the November 1993 Public Availability Sessions when this concern was raised, the children were 12, 10, 8, 7, and 1½ years old; the three oldest are boys and the two youngest are girls. The ten-year old was the child diagnosed with diabetes. The two oldest children were potentially exposed to drinking water with multiple chemicals (e.g., Tables 5A and 5B) since they used their private well. The third oldest child born in 1985, may have been exposed to prenatal and minor environmental exposure before the family moved in May 1985. From our conversations, it appears that the other siblings are in good health.

Recent sampling of this Arapahoe Aquifer well (494A) did not detect any contamination. Database queries to TCHD and the RMAED found that this residence and well are now owned by another family. Well number 494A, an Arapahoe well, has been replaced with bottled water. In addition to this well, two other wells have been utilized. Well number 494B is an Alluvial well used to water stock, and well number 494C is an Alluvial irrigation well used to water crops. The 425 ppb of DIMP detected came from a 1985 sampling effort conducted by ESE, and this level is not expected to result in adverse health effects. Environmental data show that the DIMP value of 425 ppb was probably found in either the 494B or 494C well, not the 494A well. Subsequent testing of 494A has never shown high DIMP values as high as 425 ppb (ATSDR, 1994f). A query of the RMAED disclosed that, in 1993, no reportable quantity of DIMP was detected in well 494A and 16.5 ppb DIMP was found in irrigation well 494C (ATSDR, 1994g). All of these levels of DIMP detected at this location in both the Alluvial and Arapahoe Aquifers are below the EPA LTHA of 600 ppb, therefore, adverse health effects are not expected. Although the available data for the wells in question do not indicate the presence of contaminants at levels of concern, such as those listed in Tables 13 or 14, even if those chemicals were present, they have not been found to be associated with the risk of developing diabetes.

Historically, the North Plume Group of the Alluvial Aquifer in the vicinity of these wells have been characterized by varying concentrations of the VOCs, SVOCs, and metals given in Table 5A of this Assessment. However, the most recent sampling of the underlying Arapahoe Aquifer indicates only scattered detections of DIMP, arsenic, lead, and nitrates (see Tables 5B and 14). The known risk factors for developing diabetes do not include exposure to any of the chemicals associated with RMA.

Literature reviews were conducted (ATSDR 1994j) and various groups were contacted to determine if exposure to environmental chemicals, such as the ones found at RMA, had been associated with the risk factors for developing diabetes. None of the chemicals typically found at RMA has been associated with the risk factors for diabetes (ATSDR 1994c, 1994d, and 1994i).

Refer to Appendix C for more information on diabetes.

Has Multiple Chemical Sensitivity (MCS) been associated with exposure to Arsenal chemicals?

The person who voiced this concern resided less than 3 miles southwest of RMA prior to being diagnosed with MCS and was using a private well for drinking water and other household uses. He is a landscape architect, spends a lot of his time outside at job sites, and, from our discussions, appeared to be particularly aware of the ammonia odor associated with the printing working with blueprints in his office.

If this person residing southwest of RMA was using water from his private well for drinking water and other domestic purposes, it is possible that this person may have been exposed to groundwater contaminants from the multiple industrial sources in that area. Sampling data on the well water from his well was not provided to ATSDR, so it is unknown what he might have been exposed to through ingestion of water from his well.

The causes of MCS and the biochemical mechanisms involved with it are not well understood, and there are significant differences of opinion on it's causes: some physicians believe it is caused by exposure to chemicals while others think it is a psychological phenomena. Although MCS is poorly understood, it is unlikely that, in this case, MCS would be attributed to RMA chemicals, because groundwater flow direction is to the north and northwest and prevailing winds blow predominantly to the north and northeast. It is unlikely that this particular individual would have been exposed to RMA chemicals in the groundwater or air at levels of health concern. It seems more likely that there might be chemicals in his work environment, possibly his office or outdoor work sites, that he has become sensitive to.

ATSDR is aware that this individual is working with his personal physician to identify which chemicals he is particularly sensitized to. This type of dialogue with his physician is appropriate to identify and possibly avoid the sensitizing agent or agents.

In 1992, ATSDR sponsored a conference on MCS to highlight the research currently being done in this area, especially research investigating symptoms and possible causes. Because MCS is not well understood, ATSDR is working toward establishing an interagency working group, to study the issue of MCS possibly in 1995 (Environmental Health Perspectives, 1994).

Refer to Appendix C for more information on MCS.

Have respiratory conditions such as asthma, particularly in Montbello, been associated with exposure to Arsenal chemicals?

This concern has been voiced mainly by people residing in the Montbello area south of RMA. Wind rose data indicate that the predominant wind direction is from the south to the north and northeast; groundwater flows to the north and northwest. Air monitoring performed on RMA, including data gathered from monitoring stations along the RMA boundary, has not found contaminants from RMA at levels of concern. The data does indicate that air pollution from the Denver metro area has affected air quality in areas offsite of RMA (Stollar, 1991).

Asthma is a common illness caused by a wide variety of irritants (see Appendix C for more information). Because allergic hypersensitivity is the leading cause of asthma, most cases are related to a food or allergens frequently found in homes, which may include animal danders, house dust mites, and cigarette smoke.

Although remediation during the Basin F episode in 1988 might have temporarily increased or aggravated symptoms of an asthma patient, it's unlikely that it would have caused a chronic case of asthma for people who resided north of RMA and were potentially exposed to airborne contaminants. Asthma is caused by a wide variety of irritants, so it would be difficult to pinpoint one exposure as the causal agent.

Refer to Appendix C for more information on asthma.

Has breast cancer been associated with Arsenal chemicals?

The persons expressing this concern resided about three miles northeast of RMA on a street where several residents had recently been diagnosed with breast cancer. Because they live northeast of RMA, it is unlikely that they were exposed RMA contaminants at levels of public health concern. Chemicals have migrated in the groundwater and air to the north and northwest; however, breast cancer is not caused by exposure to chemicals historically detected at RMA. The risk factors that are associated with the development of breast cancer are discussed further below.

A review of the literature was conducted to determine whether exposure to the types of chemicals at RMA have been associated with the development of breast cancer. Epidemiological studies have been conducted to investigate the possibility that DDT or its major metabolite, DDE are responsible for the development of breast cancer. One study, published in 1993, found a positive relationship between breast cancer risk and serum levels of DDE (Wolff et al., 1993, p., 648). Another study, published in 1994 found no such relationship (Krieger N. et al., 1994, p. 589). Both studies found no association between polychlorinated biphenyls (PCBs) and risk of developing breast cancer. (These studies were not related to the CDPHE exposure studies that were conducted in the communities north and northwest of RMA.) Most researchers agree that more studies are required before an association between DDE (and subsequently DDT) and breast cancer can be made. No significant exposure to these chemicals is occurring from RMA. Low levels of DDT and DDE have been found in groundwater, surface soils, and biota at levels below health-based comparison values or FDA Action Levels.

The Colorado Department of Public Health & Environment recently conducted a study to investigate cancer incidence to the north, northwest, and west of RMA for the years 1978 to 1989 and to the south for the years 1985 to 1989 (CDPHE, 1993a and CDPHE, 1993b). The study found no statistically significant excess of breast cancer.

Refer to Appendix C for more information on breast cancer.

Has throat cancer been associated with Arsenal chemicals?

The persons expressing this concern resided a little less than 3 miles northeast of RMA. Because they lived northeast of RMA, it is unlikely that they were exposed to RMA contaminants at levels of public health concern. Chemicals have migrated in the groundwater and air to the north and northwest; however, throat cancer is not caused by exposure to chemicals historically detected at RMA. The risk factors that are associated with the development of throat cancer are discussed in Appendix C.

The Colorado Department of Public Health & Environment recently conducted a study to investigate cancer incidence to the north, northwest, and west of RMA for the years 1978 to 1989 and to the south for the years 1985 to 1989 (CDPHE, 1993a and CDPHE, 1993b). The study did not find a statistically significant excess of throat cancer. However, in Area 2 (west of RMA), the lung cancer rate was elevated among both males and females during the 10-year study period. Males in the area also had a slightly higher, but not significantly higher, rate of cancer of the larynx. The lung and larynx are located further down the respiratory tract than the throat. CDPHE concluded that the pattern of lung and laryngeal cancer has several possible causes. The most significant risk factor is smoking, and others include exposure to airborne environmental contaminants, exposure to radon and occupational dusts and fumes, diets low in vitamins A and C, and alcohol consumption (CDPHE, 1993a).

Refer to Appendix C for more information on throat cancer.

Has stomach cancer been associated with chemicals that have been detected in wells north, northwest, or west of RMA?

The person who voiced this concern lives north of RMA in Henderson and worked as a furniture finisher for 40 years. He put himself on bottled water in 1967; therefore, this person has not been exposed through ingestion of groundwater for nearly 30 years. Stomach cancer has not been associated with exposure to RMA-sourced contaminants found in Offpost Study Area private wells or from any other RMA-sourced contaminants that people may have been exposed to via the air or groundwater. The Colorado Department of Public Health & Environment conducted a study to investigate cancer incidence to the north, northwest, and west of RMA for the years 1978 to 1989 and to the south for the years 1985 to 1989 (CDPHE, 1993a and CDPHE, 1993b). The study did not find a statistically significant excess of stomach cancer. The risk factors that are associated with the development of stomach cancer are discussed in Appendix C.

A relationship between the incidence of gastric cancer (stomach cancer) and concentration of nitrate in drinking water has been shown in a few studies. Two epidemiological studies found an increased incidence of gastric cancer in populations drinking water with nitrate levels of 90,000 ppb and 110,000 ppb when compared with control populations not drinking those high levels (The National Research Council, 1988, p.422-423). Those levels are much higher than the levels of nitrate typically detected in the Offpost Study Area private wells. In 1994 the level of nitrate detected in Offpost Study Area private wells typically ranged from 10,000 ppb (the MCL) to 26,000 ppb. and have decreased since that time. It should also be noted that these studies, while suggestive, do not firmly establish an association between incidence of stomach cancer and high intake of nitrate. They do indicate a need for continued intensive study on the metabolism and effects of nitrate in humans, because the series of reactions whereby nitrate in water may be converted to N-nitroso compounds (the direct carcinogenic agent) in humans is not well understood (The National Research Council, 1988, p. 421-422).

Nitrate, a non-RMA sourced contaminant commonly found in rural farming areas, has been detected in Offpost Study Area private wells (see Tables 5A, 5B, 13, 14, and 17), generally north of RMA. The most likely source of nitrates in those wells would be, not from RMA, but from the farms, stockyards, and septic sewer systems north of RMA (ATSDR, 1991, p. 2).

The earliest sampling for nitrates in the Offpost Study Area was in 1985 (ATSDR, 1994g). The levels of nitrates detected in the samples collected from 1985 into the early 1990's have been comparable to the levels given in Tables 13, 14, and 17. We do know that nitrate levels have been declining during the 1990's but, we do not know how high the levels of nitrate might have been before 1985. If the elevated levels of nitrate found in the past in well water of some wells in the Offpost Study Area were chronically ingested, non-cancerous health effects might result for certain groups of the population. Please refer to the Toxicological Evaluation section for further discussion on nitrates.

Refer to Appendix C for more information on stomach cancer.

Is there an excess of kidney cancer north, northwest, or west of RMA?

Reply:        There was no excess incidence of kidney cancer found in studies conducted for the off-post communities to the north, northwest, west, and south of RMA. The known risk factors for kidney cancer do not include RMA chemicals that have been measured in environmental media and to which people were exposed.

The Colorado Department of Public Health & Environment recently conducted a study to investigate cancer incidence to the north, northwest, and west of RMA for the years 1978 to 1989 and to the south for the years 1985-1989 (CDPHE, 1993a and CDPHE, 1993b). No statistically significant excess of kidney cancer was found. However, the study concluded that there was an excess of bladder cancer cases, as compared to "expected state rates," in males 45 to 49 years old residing north of RMA. There was no excess incidence of bladder cancer found in women.

Since CDPHE investigators observed this excess only in males, they doubt that the findings are linked to environmental exposure to RMA chemicals, because excess incidence would also be expected in women if environmental exposure was the cause of bladder cancer. CSU is completing a study that follows up on CDPHE's findings. Cancer incidence data from the Colorado Central Registry, maintained by CDPHE, will be used, and the study will also evaluate such factors as occupation, smoking status, and groundwater usage. That study is not yet completed.

The kidneys and bladder are part of the urinary tract, but they are separate organs. The kidneys remove waste products from the blood to produce urine. Urine then drains from the kidney through a long tube, the ureter, to the bladder where it is stored.

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