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PUBLIC HEALTH ASSESSMENT

WELDON SPRING ORDNANCE WORKS
WELDON SPRING, ST. CHARLES COUNTY, MISSOURI


SUMMARY

The Weldon Spring Ordnance Works (WSOW), an explosives production facility, was operated by the Atlas Powder Company from October 1940 through August 1945. The plant was built on a 17,232 acre tract of Army property in St. Charles County, Missouri.

For regulatory and remedial purposes, the original Weldon Spring Ordnance Works is divided into two National Priority List (NPL) sites. One NPL site is the responsibility of the U.S. Army. The other is the responsibility of the U.S. Department of Energy (DOE). The formal definition of the Army WSOW NPL site includes Weldon Spring Training Area (WSTA), Missouri Department of Conservation areas (August A. Busch Memorial Conservation Area and Weldon Spring Conservation Area) and numerous other small properties within the original facility boundaries. The DOE NPL site includes the Weldon Spring Chemical Plant (WSCP), Raffinate Pits and the Quarry.

This public health assessment is an evaluation of the possible public health effects of hazardous materials from U.S. Army portions of the former ordnance works. A future public health assessment will evaluate the DOE facilities.

The Weldon Spring NPL sites are in eastern Missouri between the Mississippi and Missouri Rivers, approximately 30 miles west of St. Louis. The WSOW Site was placed on the National Priority List (NPL) in 1990. Since World War II, much of the original WSOW land has been leased or sold as surplus property. Of the property sold, about 15,000 acres has been converted into two conservation areas maintained by the Missouri Department of Conservation.

Past operations have resulted in the contamination of the environment with a variety of explosives-related compounds, including TNT, DNT, and various metals. In the past, wastewaters were discharged into lagoons where the settling of explosives occurred. From the lagoons, wastewater overflow then discharged to the facility wastewater treatment plant and from there to surface water. Contaminants also migrated into soil and the groundwater (i.e., water within the earth that supplies wells and springs) via spills and operational releases from the wastewater piping systems.

The contamination of groundwater by WSOW wastewater has been known since the 1940's. Off-site groundwater contamination by nitroaromatics was documented in 1988, north of WSTA in private wells serving the Twin Island Lake Resort campground. The U.S. Army began providing drinking water to the resort in 1989. Bottled water was provided until public water supply lines were installed.

Offsite groundwater use (now prevented by alternate water sources use), consumption of possibly contaminated game and fish from the conservation areas adjacent to WSTA, and contact with contaminated soil areas are the only possible routes through which the public may come into contact with contaminants from past ordnance production activities at WSOW.

ATSDR considers present groundwater and onsite soil contamination to be categorized as No Apparent Public Health Hazard, as exposure to contaminants could occur, but institutional controls have mitigated the potential for exposure to levels that might be a health hazard. Based upon the available data, in the past, private wells may have contained contaminated groundwater and workers may have been exposed to contaminated soil. Therefore, for the time prior to institutional controls, ATSDR classifies WSOW in the category of an Indeterminate Public Health Hazard. Institutional practices initiated in 1988 and since, have reduced or eliminated this potential exposure pathway. Data is insufficient to determine potential contamination in wildlife. However, existing levels of contaminants in other environmental media are low enough that even in the event that wildlife were to bioaccumulate contaminants, the levels would not likely be high enough to result in harmful exposures to people. Also, informal observations by Missouri Department of Conservation report that fish consumption in the conservation areas is generally not subsistence in nature. ATSDR considers consumption of potentially contaminated game and fish associated with WSOW to be categorized as No Apparent Public Health Hazard.

Additional data concerning contamination outside the Weldon Spring Training Areas is being gathered and other sampling studies are being conducted to better define the source and migration of contaminants. ATSDR recommends continuing the evaluation of potential contamination in fish and groundwater. ATSDR is continuing the development of a public health assessment for public health issues regarding the DOE NPL facilities at Weldon Spring.

There is a limited potential for completed environmental pathways resulting from activities at the former WSOW, therefore extensive review of health outcome data would not provide useful information for this health assessment. However, based on the concern expressed by local members of the public about leukemia incidence, information provided by the Missouri Department of Health was reviewed. This information indicated that total childhood leukemia incidence and mortality rates within St. Charles County are not significantly elevated relative to state-wide rates. The concern regarding childhood leukemia, with general concerns about the safety of remedial activities comprised the dominant community health concerns for this site.

BACKGROUND

Site Description

The former Weldon Spring Ordnance Works (WSOW), an explosives production facility, was operated by the Atlas Powder Company from October 1940 through August 1945. The plant was built on a 17,232 acre tract of Army property in St. Charles County, Missouri (1). WSOW is located in eastern Missouri between the Mississippi and Missouri Rivers, approximately 30 miles west of St. Louis (See Figure 1).

The Weldon Spring Ordnance Works Site was placed on the National Priority List (NPL) in 1990. As currently defined for regulatory and remedial purposes, the Weldon Spring Ordnance Works (WSOW) includes the U.S. Army Weldon Spring Training Area (WSTA), Missouri Department of Conservation Busch and Weldon Spring Conservation Areas and several smaller properties within the original WSOW area (See Figure 2). This public health assessment considers the effect on public health of hazardous materials resulting from activities which occurred at the Department of Defense (DOD) WSOW Site.

The WSOW Site does not include the Department of Energy (DOE) Weldon Spring Site which is composed of the Chemical Plant (WSCP), Raffinate pits and Quarry areas. These DOE areas are grouped into the DOE Weldon Spring Site which is located within the Weldon Spring Ordnance Works Site. The DOE Quarry was placed on the NPL in July 1987 and the Chemical Plant Area was added to this listing in March 1989. The evaluation of public health effects related to the DOE sites will be made in a separate public health assessment.

The facility manufactured trinitrotoluene (TNT) and dinitrotoluene (DNT) from October 1941 through August 1945. (Note: For reference purposes, Appendix A is a glossary of abbreviations and acronyms for use throughout this document.) The facility ceased operation shortly after World War II (WW II). The plant was decommissioned in 1946 and portions of the former WSOW currently are owned by several organizations, including; the village of Weldon Spring Heights, Francis Howell School District, University of Missouri, Missouri Department of Conservation, Missouri Department of Highways, U.S. Army and the U.S. Department of Energy. At present 1,655 acres remain in Army control under the U.S. Army Engineer Center and Fort Leonard Wood, as the Weldon Spring Training Area (WSTA) of the U.S. Army Reserve (Figure 2).

Tracts totalling about 61 acres are currently property of the Francis Howell School District. The remaining 15,000 acres of the original WSOW land is now two conservation areas maintained by the Missouri Department of Conservation. The August A. Busch Memorial Conservation Area is about 8,000 acres and the Weldon Spring Conservation Area encompasses 7,000 acres (See Figure 2).

In 1954, the Army transferred 205 acres of land to the Atomic Energy Commission (AEC). The AEC property is now controlled by the DOE and is designated as the Weldon Spring Quarry, Weldon Spring Chemical Plant (WSCP) and Weldon Spring Raffinate Pits. The DOE facilities are now termed the Weldon Spring Site Remedial Action Project (WSSRAP) (See Figure 2).

Areas of Consideration

For the purpose of this public health assessment, three separate areas will be evaluated. The first is the WSTA, the portion of the original WSOW which is currently controlled by the Army. The second area is the remainder of original WSOW (including the Busch Conservation Area, Weldon Spring Conservation Area and the University of Missouri - Missouri Research Park). The portion of the original WSOW outside of Army or DOE administration will be referred to here as "the conservation areas". The third area consists of the adjacent properties outside the original boundaries of the ordnance facility. (See Figure 2)

As stated previously, the purpose of this public health assessment is to consider the public health effects of contaminants resulting from U.S. Army operations in the former WSOW site. The effects of contaminants resulting from DOE operations at the WSCP, Raffinate Pits and Quarry areas are to be considered in a separate document.

WSTA includes 16 former TNT and DNT production lines and portions of two other TNT production lines. Although the majority of the production facility structures were razed by bulldozer and burning in 1956 and 1957 (2), much of the underground pipeline used to transport explosives-contaminated wastewater remain in place on the WSTA.

Several areas now within the conservation areas were used for disposal of waste and debris. These include one dump, six burning grounds and three wastewater lagoons (3).

The offsite area evaluated consists of property outside the boundaries of WSOW. The principal medium of concern for offsite area is groundwater. Environmental sampling offsite has revealed trace amounts of contaminants from WSOW sources in some offsite private wells north and northeast of WSOW facilities.

Site Visit

ATSDR staff have made several visits to the Weldon Spring area to meet with site personnel, local, state, and federal officials, and concerned citizens. The first visit was a tour of the Weldon Spring Training Area and Former Ordnance Works facility on February 6-8, 1991. ATSDR staff met with representatives of the Army and the Missouri Departments of Health and Conservation. A site visit was made to the DOE Weldon Spring Site on June 8-12, 1992. This visit included a tour of the DOE facility and meetings with representatives of federal and state regulatory agencies, the St. Charles County School Administration, and the St. Charles Countians Against Hazardous Waste.

ATSDR staff also attended a public meeting sponsored by the U.S. Army Corp of Engineers (COE), November 20, 1992, and a public hearing sponsored by the DOE and the EPA (December 16, 1992). Concenrs regarding cancer were presented at the November 1992 meeting. The public hearing was attended by approximately 150 concerned residents with 25 people presenting specific comments regarding the "Proposed Plan for Remedial Action at the Chemical Plant Area of the Weldon Spring Site." Other individuals or groups indicated that they would provide the DOE and EPA with written comments. Community health concerns were collected at this meeting. The specific concerns are addressed later, in the Community Health Concerns section of this public health assessment.

ATSDR staff attended an EPA-sponsored demonstration for ex-situ bioremediation of explosives contaminants during a trip to the site on April 5 - 8, 1994. ATSDR staff met with representatives of EPA, the Army and the Missouri Departments of Health and Conservation. During that visit ATSDR staff also met with members of the public and medical community to discuss concerns. As a result of these meetings, follow-up public availability sessions were planned. These public availability sessions were held July 11 - 12, 1994, at two public schools in the vicinity of the Weldon Spring NPL sites. Approximately 24 members of the public participated.

Demographics

The Weldon Spring sites are located in a sparsely populated rural area of St. Charles County approximately 30 miles west of downtown St. Louis. St. Charles County had a population increase of 48 percent from 1980 to 1990 (from 162,000 to over 212,000) and has more than doubled in population since 1970; most of this rapid growth is due to people moving out from the city of St. Louis to the suburbs.

The site is located in Census Tract 3122.01 and 3122.02 (see Figure 3). These tracts are relatively large and is very sparsely populated (less than 30 persons per square mile); much of the land is devoted to agricultural use. The percentages for sex, race, Hispanic origin, age, and housing are generally comparable with those for the county, except that there is a somewhat lower percentage of children under age 10 and a much higher median value for owner occupied housing. Many of the homes in this area are large two-story single family homes on large lots (as noted on the site visit), which would account for much of the increased value.

The August A. Busch Memorial Conservation Area occupies the northern portion of WSOW and covers much of Block Group 3 in Census Tract 3122.02 (see Figure 3). The only population or housing variable for this area which differs considerably from the county averages is percent of households which are mobile homes (over 55 percent).

Extensive private well monitoring is conducted in Census Tract 3111.04. This area is much more densely populated than the other two tracts. Both persons per household and percent of children under age 10 are higher than the county averages, while percent age 65 and over is relatively low; these figures suggest that a number of young families have moved into this area, which is consistent with the "suburbanization" of recent years. Both median housing value and monthly rent are relatively high.

Land Use

Most of the property is wooded, with low shrubs and trees. Open grassy areas exist in the northern areas of the Busch Conservation Area and the Missouri Research Park. Portions of the Busch Conservation Area are used as leased cropland by local farmers. The southern and eastern portions of the conservation areas are comprised of more rugged terrain and are heavily wooded. There is reportedly very little public usage of this area (1).

In the northern portion of WSOW the topography is characterized as rolling hills. The southern portion of the site is characterized by a rugged topography, consisting of narrow, irregular drainage systems with short, steep gradient streams. The transition between these hydrologic regimes occurs in the southern portion of the WSTA and corresponds with a primary drainage basin and groundwater divide; north to the Mississippi River, south to the Missouri River (5).

Annual precipitation for this area averages approximately 37 inches/year with more than half occurring as rainfall between March and July. Annual evaporation, based on average free water surface evaporation (1956-1980 data) is approximately the same as precipitation (~37 inches/year). Prevailing winds are from the south during summer and fall, and from the northwest and west-northwest during winter and spring. Average wind speeds are about 8.7 mph for May through November and 10 mph for December through April (1).

Of the original 17,232 acre tract of Army property, approximately 8,000 acres to the north are now the August A. Busch Memorial Conservation Area, and approximately 7,000 acres to the south are now the Weldon Spring Conservation Area. Both of these areas are maintained and administered by the Missouri Department of Conservation (MDOC). The MDOC's multiple-use philosophy of land management includes: use of the land as forest and area for a wide variety of wildlife and birds; 32 stocked fishing lakes; and land leased for farming (grains and forage crops) on approximately 1000 acres south of the quarry along the Missouri River floodplain. No livestock are raised on the leased areas.

Seasonal hunting for squirrel, groundhog, dove, rabbit, white-tailed deer and wild turkey occurs by special permit. Hunting dog field trials take place on portions of the conservation management areas, and there is a practice shooting range on the August A. Busch area. Other recreational use of the land includes hiking trails, bird-watching, and a variety of educational conservation activities. The Katy Trail, a Missouri Department of Natural Resources (MODNR) park, is a major east-west hiking and bicycling trail along the former Missouri-Kansas-Texas railroad right-of-way; the trail passes within ¼ mile of the WSSRAP quarry. Edible aquatic species in the lakes in the August A. Busch area include black bass, white bass, channel catfish, flathead catfish, blue catfish, crappie, bluegill, carp, sunfish, and crayfish.

The WSOW cover two physiographic provinces: the northern portion of the site is within a dissected glacial till plain which is characterized by moderately undulating, northward dipping topography comprised of thin glacial deposits overlying limestone bedrock. The southern portion of former WSOW was not glaciated during the Pleistocene. The surficial sediments consist of alluvium and residuum overlying the limestone bedrock (5).

The unconsolidated overburden consists of silty, sandy and gravelly clays and silts, which coarsen in grain size downward. Underlying these sediments is a series of consolidated sedimentary units, predominantly limestones. Deeper units are interbedded with sandstones and shales. Geologic studies have determined these formations to be highly fractured. Over time, as groundwater moves through these fractured limestones, it dissolves the rock along the cracks and fractures, and in the naturally occurring pore spaces. This dissolution results in extremely porous formations in which groundwater flows are difficult to discern in detail. These types of geologic formations are termed "karstic". Because of the extreme porosity and fracturing, groundwater flow can vary greatly across slight geographic distances as well as varying across short vertical distances. As a result, it is often difficult or impossible to accurately determine groundwater flow patterns within an aquifer system (a water-bearing layer of rock, sand or gravel). Also, surface water and groundwater systems are often interconnected in karstic areas, with both losing streams and springs, adding to the complexity of the groundwater flow regime. It is therefore difficult to trace contaminant plume pathways in karstic environments. For the former WSOW and vicinity, the best that can be said is that groundwater flow across the area generally follows the pattern of surface water flow (1) (See Figure 4).

Three aquifer systems have been defined for the area surrounding the former WSOW. The shallowest systems are the sand and gravel alluvial aquifers of the Mississippi and Missouri Rivers, and tributaries. There are also the shallow and deep bedrock aquifers, separated by a leaky confining layer, termed an aquitard. Public water supplies in the area are predominantly supplied from the alluvial and deep bedrock aquifers (1).

St. Charles County currently owns and operates the former ordnance works wellfield which is located along the Missouri River approximately one half mile south of the Quarry site. Eight wells pump an average of 12 million gallons per day (MGD) (22 MGD maximum) from the alluvial aquifer of the Missouri River. Well depths vary from 100 to 130 feet. Water from the wellfield is sold to the St. Charles County Public Water District #2 and the Missouri Cities Water Company, serving about 60,000 people throughout St. Charles County. There are also approximately 60 private wells in the vicinity of the Weldon Spring Ordnance Works being monitored by the state of Missouri Department of Health (11).

Health Outcome Data

Health outcome data (HOD) document health effects that occur in populations. The data can provide information on the general health status of the community living near a hazardous waste site. It can also provide information on patterns of specified outcomes. Some examples of health outcome databases are tumor registries, birth defects registries, and vital statistics.

Because of the likelihood that no exposures occurred, and considering that the contaminants resulting from ordnance production are not likely to cause leukemia, extensive review of these data would not provide useful information for this health assessment. However, based on the concern expressed by local members of the public about leukemia incidence, information provided by the Missouri Department of Health was reviewed (14,15). This information indicated that total childhood leukemia incidence and mortality rates for St. Charles County are not significantly elevated relative to state-wide rates. This issue is discussed in more detail in the "Community Health Concerns" section of this document. ATSDR investigations of hospital release data and mortality records for the area have not revealed any health problems which could be related to either of the Weldon Spring sites (16). Additional evaluations of specific cancer incidence will be made of health outcome data as a part of the public health assessment for the DOE facilities.


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