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PUBLIC HEALTH ASSESSMENT

SUNFLOWER ARMY AMMUNITION PLANT
DESOTO, JOHNSON COUNTY, KANSAS


SUMMARY

Sunflower Army Ammunition Plant (SFAAP) is a government-owned, contractor-operated installation that began operation in 1942. It is located near the small town of DeSoto, Kansas, in Johnson County. The plant occupies approximately 9,065 acres in the shape of a north-south rectangle about 6 miles long by 3 miles wide. The plant's primary mission was to manufacture smokeless gunpowder and munition propellants for World War II, the Korean Conflict, and the Vietnam Conflict. Three explosives compounds (nitroglycerine, nitrocellulose, and nitroguanidine), as well as sulfuric and nitric acids, were manufactured. Munitions testing was also conducted at the site. Since 1992, SFAAP has been in inactive status. The major activities have been maintenance, environmental stabilization, and remediation. In early 1998, the U.S. Department of the Army (Army) declared that it no longer needed SFAAP and is in the process of selling the site.

During SFAAP's operations, various hazardous substances were inadvertently or intentionally released into the environment during standard disposal practices from production line areas, magazine storage areas, and solid waste management units (SWMUs). Inorganics, explosives, and nitrate compounds located in on-site soil, sediment, and groundwater are the primary contaminants.

In 1995, the U.S. Environmental Protection Agency (EPA) proposed SFAAP for the National Priorities List; however, the site was never listed. Under the Resource Conservation and Recovery Act (RCRA) Corrective Action Program a total of 65 SWMUs and 22 Areas of Concern have been identified at SFAAP and are in varying stages of investigation and remediation. Both EPA and Kansas Department of Health and Environment (KDHE) provide oversight to the program.

In September 1995, Agency for Toxic Substances and Disease Registry (ATSDR) staff conducted an initial site visit to SFAAP and in January 2000, returned to begin the data collection process for the public health assessment. During the second site visit, ATSDR met with SFAAP, EPA, and KDHE representatives and a local community group, Taxpayers Opposed to Oz (TOTO).

The pathways discussed in this public health assessment were chosen based on evaluations made during the site visits, an examination of environmental data, and concerns raised by local citizens. Based on a thorough review of the available data, ATSDR has reached the following conclusions.

Air Pathway. Under the Environmental Stabilization Project many explosive-contaminated buildings are being destroyed via open burning. Specific meteorological conditions must be met before a scheduled burn can occur. In addition, control measures are used to contain the amount of asbestos fibers and lead that are released into the air. In 1997, SFAAP conducted air sampling during three test burns to determine the levels of asbestos and lead being released by the smoke plume. Based upon the information collected during the test burns and a thorough review of the toxicological and epidemiological literature, ATSDR does not expect that people who live around SFAAP are being exposed to harmful levels of airborne asbestos or lead generated during the open burning when proper burning procedures are followed.

Surface Water and Sediment Pathway. Kill Creek, Spoon Creek, and Captain Creek are located along SFAAP's northeast, southeast, and southwest borders, respectively. Each creek drains several contaminated areas at SFAAP. Because children may play in these creeks downstream from the site, ATSDR evaluated the potential exposure to recreational users. Surface water and sediment sampling were conducted in 1994 and 1995--the detected concentrations were below levels of health concern. Therefore, recreational exposure to the surface water and sediment in Kill Creek, Spoon Creek, and Captain Creek are not expected to cause adverse health effects in children who may play in the creeks.

Kill Creek, Spoon Creek, and Captain Creek eventually discharge into the Kansas River, a designated state drinking water source. However, contamination from SFAAP is not expected to negatively affect the water quality since the levels of chemicals detected are also too low to be of health concern for anyone who may drink untreated water from these creeks on a daily basis.

Soil Pathway. The soil in many areas of SFAAP is contaminated as a result of various site activities. However, access to SFAAP is restricted by fences, and visitors are required to sign in with the guard at the entrance gate. Only the occasional trespasser might potentially come in contact with contaminated soils. This type of infrequent exposure is not expected to cause adverse health effects. SFAAP is in the process of being sold. At this time, the future use of SFAAP is uncertain. To be protective of public health, continued soil sampling and appropriate remediation would be required before the general public has access to the soils at SFAAP.

Groundwater Pathway. The groundwater at SFAAP is contaminated; however, this water is not used as a drinking water source. Therefore, no exposures are occurring and no public health hazards exist from on-site groundwater. Twenty-two off-site private groundwater wells within one mile of SFAAP are being used to supply water to households. Hydrogeologic and sampling data suggests that groundwater contamination at SFAAP is not negatively influencing the quality of drinking water at 13 of these private wells. ATSDR cannot determine the impact to nine of the private drinking water wells because data at potential sources of contamination and data from the private wells themselves are not available. This does not imply that these wells are being negatively affected, simply that additional sampling may be necessary before a determination can be made.


BACKGROUND

Site Description

Sunflower Army Ammunition Plant (SFAAP) encompasses approximately 9,065 acres near the small town of DeSoto, Kansas, in the northwest corner of Johnson County--about 28 miles southwest of Kansas City, Missouri (Figure 1, Burns 2000, Burns & McDonnell 1997a, 2002). The shape is rectangular (6 miles long by 3 miles wide) with a north-south orientation. Historically, SFAAP had 71 miles of railroad--including storage capacity for 200 cars, 79 miles of paved roads, and 35 miles of patrol roads. A total of 2,296 facilities were located on site, including 1,803 production facilities, 334 administrative buildings, and various storage structures (Aguirre 1998).

Since 1992, the majority of the site has been in standby. In 1998, SFAAP was listed as excess by the U.S. Department of the Army (Army). Negotiations for selling the site are ongoing. As of October 1, 2001, the Army changed to a maintenance contractor and reduced the number of buildings used to an office building, an environmental laboratory, the old guard headquarters as a records repository, and the guard shack at the main gate.

For the purposes of investigating the site to determine the extent of environmental contamination, SFAAP was divided into nine segments, based on major industrial processes (Figure 2, Aguirre 1998). These segments are described below.

  • Segment 1 is located in the northeastern corner of SFAAP and was used mainly for support activities, with the exception of the North Acid Area. In 1998, the land was being leased for cattle grazing. The Former and Current Administration Areas, River Intake Area, River Water Treatment Plant/Filtration Area, Water Treatment Plant, Midway Relay Station, Main Sewage Treatment Plant, Office Paper Burning Grounds, Decontamination Oven, Salvage Yard, Power Area, Classification Yard, Shop Area, North Acid Area, Industrial Wastewater Treatment Plant , Pond A, and Pond B are located within Segment 1. Very few of the facilities in this segment were removed under the Environmental Stabilization Program (please see a description of this program under Remedial and Regulatory History).

  • Segment 2 is located along the eastern border of SFAAP and includes areas that manufactured and machined solventless double-based propellant, the ballistics proving ground, and land leased by the Kansas State Horticulture Center. Most of the facilities in this segment were removed under the Environmental Stabilization Program.

  • Segment 3 is located in the east-central part of SFAAP and was the area used to manufacture concentrated nitric and sulfuric acid. It is generally referred to as the South Acid Area and contains the Nitric Acid Concentrator, Sulfuric Acid Production, Sulfuric Acid Concentrator, Liquid Waste Treatment Plant, and Pyott's Pond. Only one of the facilities in this segment was removed under the Environmental Stabilization Program.

  • Segment 4 is located in the south end of SFAAP and was originally used to store finished propellant products. Recently, a portion of the magazines (i.e., buildings where ammunition is stored) were converted to store hazardous waste. Currently, 110 storage magazines exist in the segment--15 are igloo type and 95 are above ground nonstandard type. None of the facilities in this segment were removed under the Environmental Stabilization Program.

  • Segment 5 is located in the west-central section of SFAAP. It includes areas used for the production of single-based propellant and production, glazing, blending, and packing of triple-based propellant. It contains four tunnel dryers for calcium carbonate cake and forced and passive air dryers for paste drying. Many of the facilities in this segment were removed under the Environmental Stabilization Program.

  • Segment 6 is located along the western border of SFAAP. It contains landfills, waste incinerators, explosives burning grounds, and the Lead Decontamination and Recovery Unit. The majority of the land is undeveloped and has not been used for SFAAP operations. Only one of the facilities in this segment was removed under the Environmental Stabilization Program.

  • Segment 7 is located in the center of SFAAP and contains the Nitroglycerine Area, Paste Area, and Hazard Analysis and Ballistics Laboratory. Most of the facilities in this segment were removed under the Environmental Stabilization Program.

  • Segment 8 is located in the north-central section of SFAAP and contains the Nitrocellulose Production Area, Laboratory Support, Propellant Mixing/Forming Area, Nitroguanidine Support Area, and Tank Farms. Almost all of the facilities in this segment were removed under the Environmental Stabilization Program.

  • Segment 9 is located in the northwestern corner of SFAAP and is the area that used to manufacture nitroguanidine. It contains the Calcium Cyanamide Facility, Wet and Dry Guanidine Nitrate Facilities, Wet and Dry Nitroguanidine Facilities, Pack House, Tank Farm, Sulfuric Acid Concentration Plant, Nitrogen House, and Operations Support Facilities. None of the facilities in this segment were removed under the Environmental Stabilization Program.

Operational History

SFAAP began operation in 1942 as a government-owned, contractor-operated installation called Sunflower Ordnance Works (Aguirre 1998, Burns & McDonnell 1997b). At that time, SFAAP was the world's largest powder and propellant plant, employing over 10,000 workers (Burns 2000, Johnson County 1998). During World War II, the time of peak operations, SFAAP employed over 12,000 workers (GSA 1999). The number of employees decreased as operations at SFAAP were reduced. In December 1996, SFAAP employed only 107 people (79 Alliant Techsystems employees, 21 Koch employees, 6 Army personnel, and 1 Kansas State employee) [Burns & McDonnell 1997b, Law 1997]. As of October 1, 2001, SpecPro, Inc. is the current maintenance contractor.

In 1963, the site was renamed Sunflower Army Ammunition Plant (Aguirre 1998). The plant's primary mission was to manufacture smokeless gunpowder and munitions propellants for World War II, the Korean Conflict, and the Vietnam Conflict. Two explosives compounds were manufactured for use as propellants: nitroglycerine and nitrocellulose. SFAAP has also been used to manufacture and regenerate nitric and sulfuric acids and to conduct munitions testing. The majority of the plant was put in standby, inactive status in 1971 (ATSDR 1995, EPA 1995a). In 1980, nitroguanidine production began, but ceased in 1992 (EPA 2000a). Since 1992, the major activities have been maintenance, environmental stabilization, and remediation. In early 1998, the Army declared that it no longer needed SFAAP; therefore, the General Services Administration is in the process of selling the site.

During SFAAP's operations various hazardous substances were inadvertently and intentionally released into the environment during standard disposal practices from production line areas, magazine storage areas, and solid waste management units (SWMUs). Inorganics, explosives, and nitrate compounds located in on-site soil and sediment, and groundwater beneath the site are the primary contaminants.

Remedial and Regulatory History

In 1976, Congress passed the Resource Conservation and Recovery Act (RCRA) to regulate hazardous waste practices that may have adverse effects on human health and the environment. SFAAP was issued a RCRA permit in September 1991 that authorizes SFAAP to store certain hazardous wastes for greater than 90 days and requires investigation and cleanup of releases of hazardous wastes from the SWMUs and Areas of Concern (AOCs) [EPA 2000a]. In 1995, the U.S. Environmental Protection Agency (EPA) proposed SFAAP for the National Priorities List; however, to date, the site has not been listed. Under the RCRA Corrective Action program SFAAP is working with EPA and the Kansas Department of Health and Environment (KDHE) to remediate the property. SFAAP has an active Restoration Advisory Board (RAB) that discusses restoration activities and gathers community input.

To date, 65 SWMUs and 22 AOCs have been identified at SFAAP and are in varying stages of RCRA evaluation (Figure 3). All have undergone the initial phase, called a RCRA Facility Assessment, which involves identifying sites that may affect human or environmental health. Some SWMUs are involved with more than one RCRA phase. Two SWMUs received clean closure from EPA and KDHE, and have been omitted from the RCRA evaluation. Two SWMUs were found to pose an immediate threat to human health or to the environment; therefore, interim measures were conducted to remediate the sites. Currently, RCRA Facility Investigations are being conducted on 44 SWMUs to identify the type of contaminants present. At twelve SWMUs, the contaminants have been identified and Corrective Measures Studies will be conducted to assess various cleanup options for the sites. After reviewing the public's comments on the proposed remedy, EPA, KDHE, Army Corps of Engineers, and SFAAP will adopt and follow through with a remediation plan during the Corrective Measures Implementation phase. Currently, corrective measures are ongoing at four of the SWMUs that were found to contain contamination. At the end of fiscal year 1999, one SWMU's RCRA evaluation was complete and three required long-term monitoring (Burns 2000). Investigations are planned to begin in 2003 to identify whether contamination is present at levels of concern at the 22 AOCs.

The Environmental Stabilization Program was initiated to decontaminate facilities on SFAAP and to stabilize the environment. Many of the facilities on the site were physically unsafe because of structural problems or explosive contamination. In addition, many of these facilities contained lead- and/or asbestos-containing material, however, because of the risk of explosion some of the facilities were burned prior to removal of the lead- and/or asbestos-containing material. Asbestos-containing material was removed from 455 accounts.

Through the Environmental Stabilization Program, open burning was conducted on 186 days over the past six years (this number includes building burns, reflash burns, and grass burns). Alliant Techsystems conducted a total of 228 burns, including reflash and grass burns (sometimes more than one burn occurred on the same day). A total of 1,463 accounts (i.e., numbered structures) that previously manufactured nitrocellulose, nitroglycerine, multi-based propellant, or were support facilities for propellant manufacture were included in this project. There are an additional 200 to 300 buildings that need to be demolished. However, they all contain explosive contamination that is not friction sensitive, so the asbestos siding and shingles can be removed before burning. SFAAP does not know when the funds will become available to continue the burns (KDHE 2001c).

ATSDR Activities

As part of the public health assessment process, ATSDR conducted an initial site visit to SFAAP in September 1995. The intent of the visit was to determine if immediate public health actions were needed and to prioritize the site for a public health assessment. Two documents resulted from that visit: 1) a site summary, dated December 1995, that describes SFAAP conditions and 2) a public health consultation, dated February 1996, that addresses cattle gazing on SFAAP. These documents are provided in Appendix A.

In January 2000, ATSDR returned to SFAAP to begin the data collection process for the public health assessment. They met SFAAP, EPA, and KDHE representatives, and a local community group, Taxpayers Opposed to Oz (TOTO), in order to gain an understanding of site conditions and remedial actions, and to identify community concerns. In order to monitor community concerns as they develop, ATSDR has maintained contact with regulators and members of TOTO during the public health assessment process.

Demographics and Land Use

ATSDR examines demographic information (i.e., population information) to identify the presence of sensitive populations, such as young children and the elderly in the vicinity of a site. Demographics also provide details about residential history in a particular area--information that helps ATSDR assess time frames of potential human exposure to contaminants. Demographic and land use information for SFAAP and the residential areas surrounding SFAAP are presented in this section.

Demographics

Johnson County lies in the eastern section of Kansas and is bordered by the Kansas River (also known as the KAW River) to the north and the Missouri state line to the east. The county population was estimated to be 375,000 in 1998 (DeSoto 1999). It occupies approximately 476 square miles and is home to 21 cities (Burns & McDonnell 1997a).

There are no residences on SFAAP and the area surrounding SFAAP is privately owned, sparsely populated rural land, primarily used for agriculture. The three closest towns are: Clearview City, DeSoto, and Eudora.

  • Clearview City is a retirement community located 100 feet north of SFAAP. It is located on a 65-acre parcel of private property in an unincorporated section of Johnson County. It consists of 230 multi-family units that were built during World War II to house SFAAP workers. The population is between 300-350 people (Burns & McDonnell 1997a).

  • The city of DeSoto is approximately 3 miles northeast of SFAAP and is located on 1.5 square miles along the south bank of the Kansas River (Burns & McDonnell 1997a, 2002). It was estimated to have a population of about 3,000 in 1998 (DeSoto 1999).

  • Eudora is about 4 miles northwest of SFAAP and is located on 1.2 square miles between the Wakarusa and Kansas Rivers in Douglas County (Burns & McDonnell 1997a, 2002). In 1990, the population was about 3,000 (Burns & McDonnell 1997a).

The closest school is Countryside Elementary which is located approximately 650 feet north of the SFAAP boundary. About 300 first to fourth grade students are enrolled at the school (Burns & McDonnell 1997a).

Current Land Use at SFAAP

Access to SFAAP is limited by a 6-foot high fence that surrounds the entire site. An armed security guard is positioned at the main entrance located on the main road linking DeSoto and Eudora. In addition, there is another internal fence that surrounds the manufacturing areas where most of the SWMUs and AOCs are located. A security gate is located at the entrance to this area, as well. There is no through traffic at SFAAP (Law 1997). The perimeter fence is periodically damaged, however, and occasional trespassing has been known to occur.

A few private companies lease areas of SFAAP under the Facilities Re-use Program. Currently, Southwestern Bell and Sprint operate a communication tower and Kansas State University leases over 300 acres in the southwest corner of SFAAP for agricultural research (Johnson County 1998). About 5,500 acres of undeveloped land is leased for agriculture and grazing cattle (ATSDR 1996a; Burns & McDonnell 1997b). Until their contract ended on September 30, 2001, Kansas Wastewater, Inc. leased the Industrial Wastewater Plant to treat non-hazardous wastewater from off-site facilities.

Current Land Use Surrounding SFAAP

Primarily, agricultural farmland that produces soybeans, corn, sorghum, alfalfa, and wheat surrounds SFAAP. Low density residences with large land holdings, an apartment complex, Sunflower Park (40 acres), light industry, warehouse operations, and a tire repair shop are located to the north of SFAAP. Kill Creek Park (850 acres), low density residences, and Hunt Midwest Quarry are off the eastern boundary. DeSoto Park (50 acres) and the Lexington Township cemetery are to the southwest. Land to the west is primarily agricultural with a few low density residences (Johnson County Planning Department 1998).

Proposed Future Land Use at SFAAP

Johnson County has developed a conceptual land use plan for future development at SFAAP. Future development depends on the cooperation of Kansas State, Johnson County, and the U.S. General Services Administration, and is contingent upon the transfer of sale from the federal government. To date, SFAAP has not been sold and no definitive plans have been made. Proposed re-use plans include the following (Johnson County Planning Department 1998):

  • Public park land will be established along the east, south, and west boundaries to provide a green belt buffer zone to the surrounding properties.

  • About 3,000 acres will be used for residences. Urban design criteria would allow for three to four houses an acre, as well as multi-family units in a buffer zone.

  • Near the center of the development, light industry related to high technology would encompass approximately 400 acres. It would include existing facilities such as the water treatment plant and sewage plant.

  • A town center with schools, churches, government offices, medical facilities, and downtown retail and small office establishments would cover approximately 600 acres.

  • The remaining 2,000 plus acres will be designated for a business center at the northern boundary, a research and technology center, and highway commercial zones.

Quality Assurance and Quality Control

To prepare this public health assessment, ATSDR reviewed and evaluated information which is provided in the referenced documents. Documents prepared for the RCRA programs must meet specific standards for adequate quality assurance and control measures for chain-of-custody procedures, laboratory procedures, and data reporting. The environmental data presented in this public health assessment are from reports produced by the U.S. Army Center for Health Promotion and Preventive Medicine (CHPPM), and the Army Corps of Engineers.The limitations of these data have been identified in the associated reports.

Intertek Testing Services Environmental Laboratories, Inc. (ITS) was a laboratory used by one of the Army contractors, Burns and McDonnell, to analyze samples taken from SWMUs at SFAAP. In 1999, EPA informed SFAAP that data generated by ITS at the laboratories in Richardson and Houston, Texas, are unreliable and cannot be used for decision-making at 26 SWMUs (7, 8, 9, 15, 16, 17, 20, 25, 26, 30, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 49, 51, and 52) [EPA 1999]. Because of the unreliability of the data, ATSDR did not base any health decisions upon results generated by ITS laboratories in Richardson or Houston, Texas.


EVALUATION OF ENVIRONMENTAL CONTAMINATION AND POTENTIAL EXPOSURE PATHWAYS

Introduction

What is meant by exposure?

ATSDR's public health assessment evaluations are exposure, or contact, driven. Chemical contaminants disposed or released into the environment do not always result in exposure. People can only be exposed to a contaminant if they come in contact with that contaminant. Exposure may occur by breathing, eating, or drinking a substance containing the contaminant or by skin contact with a substance containing the contaminant. Exposure does not always result in harmful effects. The sections below describe the conditions under which harmful effects might be expected to occur. Table 1 lists the potential sources of contamination at SFAAP.

How does ATSDR determine which exposure pathways to evaluate?

ATSDR scientists evaluate site conditions to determine if people could have been (a past scenario), are (a current scenario), or could be (a future scenario) exposed to site-related contaminants. When evaluating exposure pathways, ATSDR identifies whether exposure to contaminated media (soil, water, air, waste, or biota) has occurred, is occurring, or will occur through ingestion, dermal (skin) contact, or inhalation.

If exposure was, is, or could be possible, ATSDR scientists then consider whether contamination is present at levels that might affect public health. ATSDR scientists select contaminants for further evaluation by comparing them against health-based comparison values. Comparison values are developed by ATSDR from scientific literature available on exposure and health effects. These comparison values are derived for each of the different media and reflect an estimated contaminant concentration that is not expected to cause adverse health effects for a given chemical, assuming a standard daily contact rate (e.g., amount of water or soil consumed or amount of air breathed) and body weight.

Comparison values are not thresholds for adverse health effects. ATSDR comparison values establish contaminant concentrations many times lower than levels at which no effects were observed in experimental animals or human epidemiologic studies. If contaminant concentrations are above comparison values, ATSDR further analyzes exposure variables (for example, duration and frequency), the toxicology of the contaminant, other epidemiology studies, and the weight of evidence for health effects.

Some of the comparison values used by ATSDR scientists include ATSDR's environmental media evaluation guides (EMEG), reference dose media guides (RMEG), cancer risk evaluation guides (CREG), and EPA's maximum contaminant levels (MCL). MCLs are enforceable drinking water regulations developed to protect public health. CREGs, EMEGs, and RMEGs are non enforceable, health-based comparison values developed by ATSDR for screening environmental contamination for further evaluation. Appendix B describes the comparison values used in this public health assessment.

More information about the ATSDR evaluation process can be found in ATSDR's Public Health Assessment Guidance Manual at http://www.atsdr.cdc.gov/HAC/HAGM/ or by contacting ATSDR at 1-888-42ATSDR.

If someone is exposed, will they get sick?

Exposure does not always result in harmful health effects. The type and severity of health effects that occur in an individual from contact with a contaminant depend on the exposure concentration (how much), the frequency and/or duration of exposure (how long), the route or pathway of exposure (breathing, eating, drinking, or skin contact), and the multiplicity of exposure (combination of contaminants). Once exposure occurs, characteristics such as age, sex, nutritional status, genetics, lifestyle, and health status of the exposed individual influence how the individual absorbs, distributes, metabolizes, and excretes the contaminant. Together, these factors and characteristics determine the health effects that may occur as a result of exposure to a contaminant in the environment.

There is considerable uncertainty about the true level of exposure to environmental contamination. To account for the uncertainty and to be protective of public health, ATSDR scientists typically use high-end, worst-case exposure level estimates as the basis for determining whether adverse health effects are possible. These estimated exposure levels usually are much higher than the levels that people are really exposed to. If the exposure levels indicate that adverse health effects are possible, then a more detailed review of exposure combined with scientific information from the toxicological and epidemiologic literature about the health effects from exposure to hazardous substances is performed.

Figure 4 provides an overview of ATSDR's exposure evaluation process and Appendix C defines some of the technical terms used in this report.

What exposure pathways were evaluated for SFAAP?

ATSDR identified four exposure pathways at and near SFAAP for further evaluation: inhalation of particles in the air, contact with contaminated surface water and sediment, contact with contaminated surface soil, and use of contaminated groundwater. Table 2 provides a summary of the exposure pathways at SFAAP that were evaluated in this public health assessment.

  1. Pathway: Air

Are people who live near SFAAP being exposed to harmful levels of asbestos and lead during the open burnings?

Conclusions

ATSDR expects that when proper burning procedures are followed, the people who live around SFAAP are not being exposed to harmful levels of airborne asbestos or lead generated during the open burning. Asbestos was never detected and the levels that could be present, if more sensitive methods of detection were used, would not be expected to produce adverse health effects. The concentrations of lead that were detected and modeled at the fenceline were not at levels of health concern.

Discussion

Air Emissions at SFAAP

Over the past several years, Alliant Techsystems demolished hundreds of buildings (over 1,400 accounts) that were contaminated with explosives through the Environmental Stabilization Project. These buildings were removed because they were in various states of disrepair, and without removal could have posed a physical threat. The Army and the United States Army Industrial Operations Command, under the advisement of EPA and KDHE, made the decision to demolish these buildings through open burning because any friction, heat, or vibration during the removal could have caused explosions in buildings with this kind of contamination (Stutz 1997). Throughout this project, explosions occurred at about 80% of the buildings being burned (personal communication with Alliant Techsystems representative, 8/1/01).

The Environmental Stabilization Plan outlines specific measures that were taken to minimize the impact the open burning had on the surrounding communities. In buildings that did not pose an unacceptably high safety risk, asbestos siding and shingles were removed prior to burning. In addition, control systems (e.g., the use of water curtains, a fire retardant, and close monitoring by personnel) were implemented to contain fugitive material. Moreover, SFAAP was required to adhere to strict guidelines (e.g., wind speed and direction) during an open burn. Following these guidelines minimized the amount of contamination that migrated past SFAAP property (Stutz 1997).

Nature and Extent of Contamination

Some of the buildings that were burned contained asbestos and lead. To confirm that airborne levels were below concentrations of concern, SFAAP monitored air emissions during three test burns--one time critical and two non-time critical test burns. The sampling projects followed procedures established by the American National Standards, Specifications, and Guidelines for Quality System for Environmental Data Collection and Environmental Technology Programs (EnviroVisions 1997). Based on the conditions and results of the time critical test burn, CHPPM helped SFAAP develop a ground and aerial sampling plan to monitor plume air emissions during the non-time critical test burns. EPA and KDHE reviewed the plan and offered advice.

The time critical test burn was conducted on January 7, 1997. CHPPM conducted the sampling to obtain ambient air samples at a breathable height under the plume at the fenceline. Asbestos was not detected above detection limits of 0.0017 and 0.0032 fibers per cubic centimeter (f/cc). Lead was detected between 0.00858 and 0.0293 micrograms per cubic meter (µg/m3) [See Table 3, CHPPM 1997, EnviroVisions 1997]. However, due to changes in wind direction, the plume shifted and was not adequately covered by all samplers. The sampling strategy for the two non-time critical test burns were modified to account for the possibility of shifting wind direction.

During the first non-time critical sampling event on February 13, 1997, the levels of lead and asbestos were monitored at the fenceline, downwind from the burn site. As Table 3 shows, neither lead nor asbestos was detected during this event. The detection limits were between 0.46 and 0.39 µg/m3 for lead and between 0.0466 and 0.0906 f/cc for asbestos.

The second non-time critical test burn was conducted on June 26, 1997, to further evaluate potential exposures to lead and asbestos. During this event, samples were taken from within the plume while it was still on site, approximately 1,900 feet from the burn site. The one sample analyzed for asbestos did not detect the contaminant, with a detection limit of 0.0846 f/cc. Lead, on the other hand, was detected in all three samples at concentrations of 50.20, 60.59, and 60.63 µg/m3 (See Table 3, CHPPM 1997, EnviroVisions 1997).

Since lead was detected in the on-site plume, a dispersion modeling analysis was conducted to determine what the level of lead would be once the plume reached the fenceline. The analysis found that the highest lead concentration at the fenceline would not likely be higher than 0.1 µg/m3, which is well below EPA's health-based National Ambient Air Quality Standard for lead (a quarterly-average concentration of 1.5 µg/m3) [CHPPM 1997].

Evaluation of Potential Public Health Hazards

Asbestos

Even though asbestos was never detected in air samples, ATSDR reviewed the available toxicological literature for asbestos to evaluate if, as a hypothetical scenario, asbestos might have been detected had the detection limits been lower--and if asbestos was detected at a level between zero and 0.0906 f/cc, would this potential concentration cause any adverse health effects. Because the highest detection limit for these samples was 0.0906 f/cc, ATSDR reasons that ambient air concentrations of asbestos could not be greater than this level during the test burns. No information is available on the size, shape, or composition of asbestos fibers released during the SFAAP test burns because asbestos has yet to be detected in any air sample.

Prolonged inhalation exposure to elevated levels of asbestos has been found to cause many adverse health effects, especially to the lung (e.g., asbestosis and mesothelioma) [ATSDR 1999b]. However, ATSDR does not believe any such effects have or will occur among residents who live near SFAAP for two reasons.

  • First, the results of many health studies have confirmed that the likelihood for developing asbestos-related diseases is largely a function of the duration of exposures: those who have been exposed the longest (e.g., workers in asbestos mines or long-term residents near facilities that process asbestos) are the most likely to have adverse health effects. However, the duration of exposure to asbestos at SFAAP, if any, is assumed to be rather short (burning only occurred on 186 days over the last six years, with 72 days being the maximum in a single year).

  • Researchers typically characterize exposure to asbestos as 'cumulative exposures,' or the product of the exposure concentration and the duration of exposure.Second, the concentrations of asbestos in the air at SFAAP, if asbestos is indeed present, are clearly much lower than those that are known to cause adverse health effects. More specifically, based on the information presented above, cumulative exposure to asbestos among residents near SFAAP from the burning structures is probably no greater than 0.54 fiber-year/cm3 (or fiber-year/ml). ATSDR calculated this by multiplying the highest detection limit for asbestos (0.0906 f/cc) by an assumed 6-year duration of exposure. Actual exposures are probably much less, because we know that ambient air concentrations were lower than the reported detection limit, and buildings are not burned continuously throughout the entire six years.

Nonetheless, the available data suggest that these exposure levels, over the short term, are not associated with any adverse health effects:

  • Non-cancer effects. Several studies of people exposed to asbestos at levels between 2.6 and 90 fiber-year/cm3--levels much higher than exposures at SFAAP--did not suffer from increased incidence of several specific non-cancer respiratory diseases and conditions [ATSDR 1999b]. This suggests that even if exposures to 0.54 fiber-year/cm3 occurred among residents near SFAAP, such exposures would not be associated with adverse non-cancer respiratory health effects.

  • Cancer effects. Numerous studies have linked exposure to asbestos to different types of lung cancer (ATSDR 1999b). Most of these studies found cancer effects occurring among workers who are frequently exposed to asbestos, and some have found cancer effects in communities around industrial facilities that process asbestos. ATSDR has found no evidence of increased cancer risk in residential populations with brief and intermittent exposures to very low levels of asbestos, as might occur in the community surrounding SFAAP.

In summary, asbestos has not been detected in the air surrounding SFAAP when on-site buildings have been burned. Therefore, the exposure concentrations in the area cannot exceed the reported detection limits for the air sampling projects. Though ATSDR would have preferred that the air sampling had been conducted using more sensitive methods, the available data suggest that no adverse health effects have occurred as a result of the open burning of buildings at SFAAP. Inhalation exposures to asbestos at SFAAP, if any have occurred, clearly were not at levels that are known to cause adverse health effects.

Lead

Even though lead was detected in the on-site plume, the test burns, supported by the dispersion modeling analysis, suggests that ambient air concentrations of lead are not at levels of health concern at off-site locations because concentrations at the fenceline are below EPA's National Ambient Air Quality Standards. In addition, following the guidelines during an open burn minimizes the amount of lead that migrates off site. Based on these observations, inhalation exposure to lead during the burnings would not be expected to cause adverse health effects.

Additionally, ATSDR examined the potential for downwind deposition of lead by comparison with large-scale lead smelting operations (ATSDR 1994, ATSDR 1997, ATSDR 1999a). Based on evaluations made at these types of sites, that process large amounts of lead for long periods of time, deposition of lead decreases below the action level (400 ppm) within approximately 1,000 feet from the source. As a result of this finding, it is not likely that enough lead would reach off site to pose a public health hazard. Future use decisions for SFAAP should take the potential for on-site deposition into account.

Smoke

Sensitive populations (e.g., children, elderly, and people with respiratory conditions or heart disease) may experience lung irritation and other acute respiratory health effects if they inhale large quantities of smoke from the open burnings. If these health effects occur, they are typically reversible and subside after the fires are extinguished. SFAAP should continue to notify residents, especially sensitive populations, when the open burning are scheduled, so that they can take measures to reduce their exposure.

  1. Pathway: Surface Water and Sediment

Is the general public being exposed to harmful levels of chemicals detected in the surface water and sediment of Kill Creek, Spoon Creek, and Captain Creek?

Conclusions

No. The public is supplied with treated drinking water from the Kansas River and associated alluvium. While Kill Creek, Spoon Creek, and Captain Creek flow into the Kansas River, the chemicals that were detected in these creeks are not likely to influence the public water supply three miles away because, based on toxicological and epidemiological evaluations, the potential exposure that could result from the concentrations found are below levels of health concern. Additionally, recreational exposure to the surface water and sediment were also below levels of health concern.

Discussion

Hydrology

There are three perennial streams (Captain Creek, Spoon Creek, and Kill Creek), one ephemeral stream (Hansen's Creek), two lakes (Robert's Lake and an unnamed oxbow lake), and three ponds (Pond A, Pond B, and Pyott's Pond) at SFAAP. The majority of the surface drainage from SFAAP runs into the three perennial streams that flow north and discharge into the Kansas River (Aguirre 1998, Burns & McDonnell 1997a, 2002).

  • Kill Creek drains the northeast corner of SFAAP, including Pond A, Pond B, Pyott's Pond, and Hansen's Creek. It receives surface water run-off from the munitions production area (F-Line), the nitroglycerine areas, the former Koch area, the potable water treatment plant, the nitrocellulose production area, the photography lab, the sewage treatment plant, boiler blowdowns, the north acid/chromate area, and the calcium carbide storage area.

  • Spoon Creek receives run-off from the southeastern section of SFAAP, including part of the munitions storage area, the hazardous waste storage magazines, the munitions production area (F-Line and N-Line), the paste area, the ballistics/proving grounds, the mechanized roll area, and 13 square miles of off-site agricultural land.

  • Captain Creek drains the western section of SFAAP, including Robert's Lake and an unnamed oxbow lake, located in the west-south central section of SFAAP. It receives surface water run-off from part of the munitions storage and production areas, the burning grounds, the solvent area, the lead recovery area, the south part of the nitroguanidine production area, the contaminated waste processor, and the landfill area.

Surface Water Use

Alluvium is defined as sediments deposited by flowing water.The Kansas River is located about 3 miles north of SFAAP's northern boundary and is a state designated drinking water supply. The cities of DeSoto and Eudora receive their public water supply from groundwater wells located to the north and south of the Kansas River, in the Kansas River Valley alluvium. SFAAP obtains its water supply from 11 groundwater wells that are considered to be under the influence of the Kansas River. Five wells are located south of the Kansas River and six wells are located north of the river. Currently, only three of the wells in the North well field are being used (Aguirre 1998; City of DeSoto 2000). Clearview City purchases its water supply from SFAAP.

Kill Creek, Captain Creek, and Hansen's Creek are designated by the state of Kansas for expected aquatic life use, domestic water supply, food procurement (e.g., fishing), groundwater recharge, industrial water supply, irrigation, and livestock watering (Law 1997). Downstream of SFAAP, Kill Creek is a designated fishery (EPA 2000a). Spoon Creek is only designated for expected aquatic life use. Robert's Lake is used for recreational purposes by SFAAP employees.

Nature and Extent of Contamination

Kill Creek. Twenty-six SWMUs (1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 20, 24, 25, 30, 33, 34, 35, 37, 38, 39, 40, 46, 50, 51, and 52) are located within the Kill Creek watershed, which also receives flow from Spoon Creek. Surface water and sediment from Kill Creek were sampled for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), metals, explosives, pesticides, sulfate/sulfide, nitrate/nitrite, fluoride, and total dissolved solids in 1994 and 1995. Twelve metals, one VOC, one SVOC, one pesticide, sulfate, nitrate/nitrite, and fluoride were detected in the surface water. Twenty metals, three VOCs, three SVOCs, one pesticide, nitrate/nitrite, and fluoride were detected in the sediment (Law 1998).

Spoon Creek. SWMUs 10, 11, 13, 14, 15, 16, 36, and 43 are within the Spoon Creek watershed. In 1994 and 1995 surface water and sediment in Spoon Creek were sampled for VOCs, SVOCs, metals, explosives, pesticides, sulfate/sulfide, nitrate/nitrite, fluoride, and total dissolved solids. Eleven metals, one VOC, four SVOCs, ammonia, sulfate, nitrate/nitrite, and fluoride were detected in the surface water. Twenty-one metals, two VOCs, four SVOCs, one pesticide, nitrocellulose, and nitroglycerine were detected in the sediment (Law 1998).

Captain Creek. Sixteen SWMUs (17, 18, 19, 21, 22, 23, 26, 27, 31, 32, 40, 41, 42, 43, 44, and 47) are located within the Captain Creek watershed. Surface water and sediment from Captain Creek were sampled for VOCs, SVOCs, metals, explosives, sulfate/sulfide, nitrate/nitrite, fluoride, and total dissolved solids in 1994 and 1995. Ten metals, one VOC, one SVOC, sulfate, nitrate/nitrite, and fluoride were detected in the surface water. Nineteen metals, two VOCs, four SVOCs, two pesticides, and sulfate were detected in the sediment (Law 1998).

Evaluation of Potential Public Health Hazards

Of the chemicals detected in the surface water and sediment, many were below ATSDR's comparison values and were not considered to be of health concern. While concentrations at or below the relevant comparison values may reasonably be considered safe, it does not automatically follow that any environmental concentration that exceeds a comparison value would be expected to produce adverse health effects. It cannot be emphasized strongly enough that comparison values are not thresholds of toxicity. The likelihood that adverse health outcomes will actually occur depends on site-specific exposure conditions, not an environmental concentration alone. Those chemicals that were detected in Kill Creek, Spoon Creek, and Captain Creek above comparison values are listed in Table 4, Table 5, and Table 6, respectively.

Exposure from drinking surface water

After leaving SFAAP, Kill Creek, Spoon Creek, and Captain Creek travel for 3 linear miles and eventually drain into the Kansas River, a state designated water supply. Even though contamination is present on site, it is improbable that surface water from SFAAP would adversely affect drinking water supplies. First, this type of contamination is not expected to travel this distance. VOCs tend to quickly volatilize out of surface water and metals tend to settle into the sediment. Second, the water is treated prior to its use and must meet specific drinking water quality standards set by EPA. Under the authorization of the Safe Drinking Water Act, EPA has set national health-based standards to protect drinking water and its sources. Each city has its own water treatment plant and KDHE monitors the public water supply from the Kansas River and associated alluvium.

An exposure dose is the amount of chemical a person is exposed to over time. When estimating exposure doses, health assessors evaluate contaminant concentrations to which people may have been exposed and length of time and the frequency of exposure. Together, these factors influence an individual's physiological response to chemical contaminant exposure and potential outcomes. Where possible, ATSDR used site-specific information about the frequency and duration of exposures. In cases where site-specific information was not available, ATSDR applied several conservative exposure assumptions to estimate exposure doses.It should be emphasized that the water in the creeks that flows through SFAAP is not representative of water quality people are using at the tap. As mentioned above, drinking water is treated prior to being used. Typical water treatment systems use processes such as filtration, flocculation, sedimentation, and disinfection to provide safe drinking water to the public. More information concerning the Safe Drinking Water Act and drinking water treatment can be found in Appendix D, by visiting EPA's website at http://www.epa.gov/safewater , or by calling EPA's Safe Drinking Water Hotline at 1-800-426-4791.

However, to address the improbable scenario that water from Kill Creek, Spoon Creek, and Captain Creek is being consumed (without treatment prior to drinking), ATSDR calculated exposure doses (please see the box for an explanation) for the chemicals detected above comparison values. Adults were assumed to drink 2 liters of water a day and children 1 liter of water a day. The resulting exposure doses were below levels of health concern when compared to values documented in the toxicological and epidemiological literature. Therefore, no adverse health effects are expected from drinking the surface water from Kill Creek, Spoon Creek, and Captain Creek.

Recreational exposure from incidentally ingesting surface water and sediment

Even though Kill Creek, Spoon Creek, and Captain Creek are not specifically designated for recreational use, it is possible that children may play in the creeks during the summer. Therefore, ATSDR calculated recreational exposure doses assuming adults and children incidentally ingested 0.15 liters of water a day and 50 milligrams (mg) [for adults] to 100 mg (for children) of sediments a day for 130 days of the year. Based on these conservative assumptions, no one is being exposed to harmful levels of chemicals in the surface water and sediments in Kill Creek, Spoon Creek, and Captain Creek.

Recreational exposure from dermal contact with surface water and sediment

Again, Kill Creek, Spoon Creek, and Captain Creek are not specifically designated for recreational use, however, it is possible that children may play in the creeks during the summer. Therefore, ATSDR calculated recreational dermal exposure doses assuming total body exposure to the surface water and sediment for 3 hours a day for 130 days a year. The permeability of the skin to a chemical is influenced by the physicochemical properties of the substance, including its molecular weight (size and shape), electrostatic charge, hydrophobicity, and solubility in aqueous and lipid media. Taking these chemical-specific factors and exposure assumptions into consideration, no one is being exposed to harmful levels of chemicals in the surface water and sediments in Kill Creek, Spoon Creek, and Captain Creek from dermal contact.

Exposure from eating fish from Kill Creek or Captain Creek

Kill Creek and Captain Creek are designated by the state of Kansas for food procurement, such as fishing. Fish from Kill Creek (approximately 1.25 river miles downstream from SFAAP) were collected and analyzed for metals, pesticides, polychlorinated biphenyls (PCBs), and organic compounds in 1989-1996 (EPA 1989-1996; see Table 7). ATSDR calculated exposure doses for the chemicals that were detected in the fish. Adults and children were assumed to eat seven meals of fish from Kill Creek each month (adults were estimated to eat 8 ounces of fish every meal and children were estimated to eat 4 ounces of fish every meal). The resulting exposure doses were below levels of health concern when compared to values documented in the toxicological and epidemiological literature. Therefore, no adverse health effects are expected from eating fish from Kill Creek.

At this time, ATSDR is unaware of any fish surveys or sampling that has occurred in Captain Creek. Therefore, to address this issue, ATSDR carefully evaluated the available surface water and sediment data to determine if the chemicals present were detected at concentrations that could potentially accumulate in fish tissue at harmful levels. ATSDR determined that the nature and concentrations of the chemicals found in Captain Creek do not indicate that eating fish from these creeks would pose any health hazards. However, without evaluating fish sampling data, no definitive analysis can be made.

  1. Pathway: Surface Soil

Is the general public being exposed to harmful levels of chemicals detected in the soils at SFAAP?

Conclusions

No. Access to SFAAP has always been and is still restricted. Without exposure, no adverse health effects can be expected to occur. Even the occasional trespasser is not coming in contact with contaminated soils often enough or in high enough doses to be a cause for health concern. The future use of SFAAP is undetermined at this time. Continued sampling and remediation appropriate for the type of future use would be required prior to allowing people access to the soils at SFAAP.

Discussion

Geology

SFAAP is underlain by unconsolidated overburden and bedrock. Except where disturbed, a thin, organic-rich layer of topsoil exists throughout the site.

  • The unconsolidated overburden consists of clays, silts, and sands in the upland overburden and clays, silty clays, and sands in the alluvial deposits along the creeks. The upland overburden can range from 1 foot thick on the side slopes of the ridges and ravines on the eastern and western edges of the plant to 46.5 feet thick in the relatively flat upland portions of the plant. The alluvial deposits are about 8.5 to 12 feet thick along Kill Creek and Spoon Creek and range from 13 to 15 feet thick along Captain Creek (Burns & McDonnell 1997b).

  • Underneath the unconsolidated overburden lies the bedrock. The near surface bedrock beneath SFAAP consists of approximately 500 feet of limestones, shales, and sandstones. A north-south trending ridge runs through the center portion of SFAAP, which causes the bedrock surface to dip away to the east and west. The overall slope of the bedrock is to the west (Burns & McDonnell 1997b).

Land Use

In the past, processing facilities produced nitrocellulose, nitroglycerine, nitroguanidine, various propellant end products, nitric acid, and sulfuric acid. Administrative, maintenance, and logistic support facilities were also part of the operation. Since 1992, SFAAP has been in standby status. Currently, the majority of land (about 5,500 acres) is used for hay production and cattle grazing. Also, a few tenants (Southwestern Bell and Sprint and Kansas State University) lease areas on SFAAP under the Facilities Re-use Program. Historically, housing for SFAAP workers was, and still is, off site (Burns & McDonnell 1997b). The future use of SFAAP is undetermined at this time.

Access to SFAAP is limited by a 6-foot high fence that surrounds the entire site and an internal fence that surrounds the manufacturing areas where most of the SWMUs and AOCs are located. An armed security guard is positioned at the main entrance (Law 1997). The perimeter fence is not well maintained; however, and occasional trespassing has been known to occur.

Nature and Extent of Contamination

Table 1 contains chemicals in surface soil that were detected above comparison values in the SWMUs with data available. A site-wide summary of the available data is compiled in Table 8. Seven metals (antimony, arsenic, cadmium, copper, iron, lead, and manganese) were detected above comparison values at various SWMUs across SFAAP. Six SVOCs [benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, bis(2-ethylhexyl)phthalate, dibenz(a,h)anthracene, and indeno(1,2,3-cd)pyrene] were also detected above comparison values. An additional three SVOCs [acenaphthylene, benzo(g,h,i)perylene, and phenanthrene] were detected in the surface soil, but did not have comparison values. Three pesticides (aldrin, chlordane, and dieldrin) were detected above their CREGs and one pesticide (endrin ketone) did not have a comparison value. Only one PCB, Aroclor-1260, was detected above comparison values at SWMU 3. Dioxins/furans were detected at elevated levels at five of the SWMUs. One explosive, nitroglycerine, was detected above its comparison value. However, three others (guanidine nitrate, nitrocellulose, and pentaerythritol tetranitrate) were detected in the surface soil but did not have comparison values.

An additional source of site-wide soil contamination is the asbestos-insulated steam pipes that run throughout SFAAP. The wrap that keeps the asbestos on the steam pipes is not maintained in many areas. In addition, cattle have rubbed against the pipes and inadvertently dislodged asbestos. No soil sampling has been conducted underneath the steam pipes to quantify the extent of contamination.

Evaluation of Potential Public Health Hazards

Again, environmental concentrations that exceed comparison values would not automatically be expected to produce adverse health effects. It cannot be emphasized strongly enough that comparison values are not thresholds of toxicity. The likelihood that adverse health outcomes will actually occur depends on site-specific exposure conditions, not an environmental concentration alone.

Past and Current Exposures

Access to SFAAP has always been limited to the general public by fences and guards. Visitors must sign in at the security gate prior to entry. Therefore, because there is not access, the public is not being exposed to contamination located in the surface soil on site. Even though the occasional trespasser may gain access to SFAAP through a breach in the perimeter fence, that person would not be expected to be exposed to high levels of contamination for any length of time nor on a regular basis. Additionally, the trespasser is probably not a young child and would not be as predisposed to incidentally consume or come in contact with contaminated soil as a child might. For the substances present in soil at SFAAP, adverse health effects are not expected to occur from this kind of infrequent and occasional exposure to contaminated surface soil.

Future Exposure

It is difficult for ATSDR to address future health hazards from contact with contaminated soil because the future use of the land has not yet been determined. It is apparent from the available sampling data that certain SWMUs will require remediation before unrestricted access can be granted. To add to the difficulty, many of the SWMUs were previously evaluated using data from ITS in which their conclusions are no longer valid (please see the Quality Assurance and Quality Control section). The Army has plans to resample many of the SWMUs affected by this situation. However, currently many of the SWMUs do not have usable data upon which to make a public health decision concerning the potential future use of the site. Contamination at these SWMUs should be defined, evaluated and, if necessary, remediated before people have access to the site. In addition, breathing in airborne asbestos fibers is a health concern that should be considered if and when the public is allowed open access to SFAAP. If definite plans are made for SFAAP to be opened to the public and after sampling data are available, ATSDR can assist with determining appropriate health-based cleanup levels specific to the chosen future use.

  1. Pathway: Groundwater

Is the general public being exposed to harmful levels of chemicals detected in the groundwater at SFAAP?

Conclusions

The groundwater at SFAAP is not used to supply drinking water. Since no one is drinking contaminated groundwater, no one is being exposed to harmful levels of chemicals. Within one mile of SFAAP there are twenty-two off-site private groundwater wells used to supply water to the household. Hydrogeologic and sampling data suggest that groundwater contamination at SFAAP is not affecting the quality of drinking water at 13 of these private wells. ATSDR cannot determine the possible impact to nine of the private drinking water wells because data at some of the SWMUs and AOCs located on the western and northern borders are not available.

Discussion

Hydrogeology

Groundwater under SFAAP can be found within two aquifers: the unconsolidated aquifer and the bedrock aquifers. Groundwater mixing can occur between the unconsolidated aquifer and the bedrock aquifers. However, due to a permeability difference that exists between the two aquifers, groundwater mixing is most likely limited (Burns & McDonnell 1997b).

  • The unconsolidated aquifer reaches a maximum depth ranging from 70 to 100 feet below ground surface, with a water depth at 0 to 40 feet below ground surface. Groundwater in the unconsolidated aquifer exists within two regimes: the upland overburden and the tributary alluvium. Groundwater in the upland overburden can be found in the soil that extends from the ground surface to the bedrock, consisting of clays, sand, and gravelly sand. However, groundwater is not always present, especially in areas where the bedrock is near the surface. Generally, groundwater in the upland overburden flows east and west away from a centrally located north-south ridge. However, in the northwest half of the north end of SFAAP, groundwater flow is towards the north (KDHE 2001). Groundwater in the tributary alluvium is located in silt, clay, limestone, and gravel along the tributary creeks (i.e., Kill Creek, Spoon Creek, and Captain Creek). Unlike the Kansas River Valley alluvium, the tributary alluvium does not generally yield large quantities of water (i.e., about 1 to 10 gallons per minute for Spoon Creek and Kill Creek and up to 25 gallons per minute for Captain Creek) [Burns & McDonnell 1997b, Law 1997].

  • Groundwater aquifers at SFAAP can be found in shale and limestone formations of the bedrock. Water yields in the bedrock are generally low (i.e., below 10 gallons per minute). Groundwater in the shallow bedrock tends to flow to the west-southwest in the northern portion of the plant and to the west-northwest in the southern portion of the plant (Burns & McDonnell 1997b, Law 1997).

Precipitation is the primary source of recharge to the regional water table. Drainage from streams, ponds, and subsurface sources contribute considerably less. Recharge to the groundwater is seasonal with the greatest influx during the spring. Groundwater from the unconsolidated aquifer eventually discharges to surface water or migrates into the bedrock.

Groundwater Use

SFAAP and the surrounding areas obtain their public water supplies from wells located to the north and south of the Kansas River in the Kansas River Valley alluvium. Clearview City attains its water from SFAAP. DeSoto and Eudora receive their public water from the groundwater wells in the Kansas River Valley alluvium (Aguirre 1998, Law 1997).

Prior to the existence of SFAAP, former residents used private wells to provide water. Some of these wells still exist on the site, however, these wells are not in working condition to provide water. Groundwater under SFAAP is not currently used to provide drinking water; and there are no plans for the groundwater to be used to supply drinking water in the future.

Private groundwater wells are used in the area surrounding SFAAP. From 1998 through 1999, a contractor for the Army conducted a comprehensive inventory of water supply wells within one mile of SFAAP. Record searches of the KDHE database and the Kansas Geological Survey database were performed in November 1998. In addition, mailings were sent and telephone calls were placed to local parcel owners from December 1998 to May 1999. From these efforts, 83 private groundwater wells were identified. Most wells were not in use; 30 wells were being used to supply water to the household, to irrigate lawns and gardens, or to water livestock. Three additional wells were planned to be used in the future. Of the 33 wells in use or planned for use, 11 were not being used to supply drinking water; twenty-two wells were being used for household/domestic purposes (e.g., drinking). These domestic drinking water wells are located to the north, west, and south of SFAAP. None of the wells to the east of SFAAP were being used to supply water to the household (Burns & McDonnell 1999).

Nature and Extent of Contamination

A comprehensive overview of groundwater contamination at SFAAP was conducted by one of the Army contractors. It included available data from 1994 through 1996. However, some of these data were generated by ITS and were later determined to be unreliable by EPA (please see Quality Assurance and Quality Control discussion). ATSDR did not use data that were generated by ITS.

Table 1 contains chemicals in groundwater that were detected above comparison values for SWMUs where data are available. A site-wide summary of the available data are compiled in Table 9. Eight metals (antimony, arsenic, barium, cadmium, manganese, nickel, thallium, and vanadium) were detected above comparison values at various SWMUs across SFAAP. Only one SVOC, bis(2-ethylhexyl)phthalate, was detected at an elevated level at SWMU 24. Two explosives (nitroglycerine and nitroguanidine), ammonia, fluoride, nitrate/nitrite, and sulfate were also detected above comparison values at various SWMUs. Guanidine nitrate and sulfide did not have comparison values, but were each detected in groundwater at two SWMUs.

Evaluation of Potential Public Health Hazards

Again, environmental concentrations that exceed comparison values would not automatically be expected to produce adverse health effects. It cannot be emphasized strongly enough that comparison values are not thresholds of toxicity. The likelihood that adverse health outcomes will actually occur depends on site-specific exposure conditions, not an environmental concentration alone.

Past and Current Exposures

No one in the past or currently is being exposed to contaminated groundwater at SFAAP because no one has/is drinking water from on-site wells. SFAAP and the surrounding cities are supplied with treated public water from groundwater wells within the Kansas River Valley alluvium. KDHE monitors the public water supply to ensure that it meets specific drinking water quality standards set by EPA.

People using water from private groundwater wells outside of SFAAP might be exposed if contaminated groundwater from SFAAP migrates off site. The groundwater in the upland overburden tends to flow to the east and west and the groundwater in the bedrock aquifers tends to flow to the west. In the northwest half of the north end of SFAAP, groundwater flow is towards the north. Therefore, based upon the movement of groundwater, wells to the south are cross-gradient from the groundwater flow, making contaminant migration into these wells improbable. Wells that are potentially downgradient from SFAAP are located to the north, west and east. While there were no drinking water wells identified to the east of SFAAP, there were six wells to the north and nine wells to the west identified as being in use. These 15 wells could be affected if contamination in the groundwater from the north or west side of SFAAP flowed off site.

Several SWMUs (2, 18, 19, 21, 22, 27, 31, 32, 44, 45, 47, 49, 57, and 59) and AOCs (14 and 17) are located along the north and west border of SFAAP. Of these, there is sampling at nine SWMUs (2, 18, 19, 21, 22, 27, 31, 32, and 47) and sampling is planned for three others (44, 45, and 49). Even though SWMU 49 and AOC 17 have not been sampled directly, data is available for SWMUs 18, 19, 27, and 47, which are located in the same general areas as SWMU 49 and AOC 17. Leaving the possible contamination at four SWMUs (44, 45, 57, and 59) and AOC 14 unknown at this time.

Of the 15 private wells located to the north and west of SFAAP, data were available for areas upgradient from six private wells located to the west of SFAAP; therefore, a determination about the potential health effects from groundwater moving off site could be made for these six wells. ATSDR evaluated the available data and determined that the chemical concentrations were either too low to be of health concern for adults drinking 2 liters of water and children drinking 1 liter of water every day or their concentrations were too low to be of health concern by the time the groundwater reached SFAAP's border.

There is not enough data to evaluate whether the remaining nine off-site, drinking water wells (six to the north and three to the west) are being influenced by SFAAP because groundwater data is not available at some of the potential sources of contamination (SWMUs 44, 45, 57, and 59 and AOC 14) that are located upgradient from them. Additionally, data is not available from the nine private wells themselves. Therefore, at this time, ATSDR is unable to determine whether chemicals potentially found in the groundwater are migrating to these nine wells at a harmful level. The potential does exist for contaminants to follow the groundwater flow and migrate into these wells, however, that does not imply that there is currently a health hazard, simply that more data is needed before an evaluation can be made.

In conclusion, of the 22 wells being used (or planning to be used) to supply drinking water to the household, 13 are not being negatively influenced by chemicals at SFAAP. In order to help evaluate the potential for contaminated groundwater at SFAAP to migrate into off-site wells, ATSDR concurs with the planned evaluation of SWMUs 44, 45, and 49 and encourages plans be made to sample SWMUs 57 and 59 and AOCs 14 and 17.

Future Exposure

At this time there are no plans to use the currently existing wells or to install new drinking water wells on SFAAP property. The aquifers do not seem to be very productive (i.e., do not yield high volumes of water). However, because future use of the site may include residential areas, private groundwater wells may be installed or the old ones utilized. To be protective of public health, additional sampling to determine the full extent of groundwater contamination at SFAAP would also be essential. Based on the results of this work, remediation might be necessary prior to groundwater being used as a source of drinking water.

Potential future exposure of people to drinking water from private groundwater wells near SFAAP is the same as past and current exposures. Thirteen of the 22 wells being used to supply water to households are not being influenced by SFAAP now and are not expected to be influenced in the future because further contamination is not expected to occur. There is uncertainty about groundwater contamination in nine private, off-site wells downgradient from sites without data. Future exposure from these wells is uncertain until sampling data can be evaluated.



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