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PUBLIC HEALTH ASSESSMENT

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


ENVIRONMENTAL PATHWAYS, ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS


Introduction

The release of contaminants into the environment from WSOW has been documented. To determine whether people are exposed to on-site contaminants or to contaminants migrating from the site, ATSDR evaluates the environmental and human components that lead to human exposure. This pathways analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. The release of contaminants into the environment does not always result in exposure. For adverse health effects to occur, two principle criteria must be met. The exposure pathway must be completed, and the exposure dose must be sufficient to cause adverse health effects.

WSOW Environmental Pathways

Chemicals routinely manufactured, handled, and stored at WSOW during its operation have been detected in WSTA soil, and in offsite groundwater, surface water and, to a lesser extent, in biota. For the purpose of this public health assessment, three areas are evaluated for hazardous chemicals from WSOW ordnance operations. These are; WSTA, the portion of the original WSOW which is currently controlled by the Army; the "conservation areas", including the Busch Conservation Area, the Weldon Spring Conservation Area, and the University of Missouri Research Park; and the adjacent off-site areas that are not a part of the former WSOW, but which may have received contamination (See Figure 2).

The WSOW and WSTA Remedial Investigation (RI) environmental sampling programs provide information about the extent of contamination from the ordnance works (1,18, 30). Contamination resulting from past ordnance production activities at WSOW has been detected in groundwater and soil onsite. Soil contamination has been found in restricted portions of the conservation areas. Very limited amounts of contamination have been found in surface water in the conservation areas and in the groundwater offsite. The main potential public health issues evaluated in this document are; groundwater contamination offsite, possible biota contamination in the conservation areas, and localized soil contamination within the WSTA and in limited and isolated areas of the conservation areas. People who may have been exposed include, respectively; users of private wells, hunters and anglers using the conservation areas, and site workers, army personnel or trespassers at WSTA. As the following sections will show, although groundwater has been contaminated, current institutional controls have eliminated this as a medium of concern for a completed pathway. Also, soil onsite, and in restricted conservation area locations, is contaminated. Institutional controls have also eliminated soils as a medium of concern for a completed pathway. Fish and game are potentially exposed to contaminants from past ordnance production activities. The potential exposure of wildlife to these chemicals is at a level low enough that consumption of biota from the WSOW and vicinity is not a significant concern. Table 1 presents a summarized evaluation of the environmental pathways that may be of concern. The following sections describe the potential for contact with contaminants resulting from activities at WSOW. Issues related to contaminants in environmental pathways associated with operations at the DOE NPL facilities will be evaluated in a future public health assessment.

Nature and Extent of Contamination

Introduction

The contaminants discussed in the public health assessment are evaluated based on known or possible human exposure, and whether exposure to the contaminants has public health significance. ATSDR and other agencies have developed comparison values (CVs) to provide guidelines for estimating the media concentrations of a contaminant that are unlikely to cause adverse health effects, given a standard exposure rate and standard body weights. These CVs are developed to address health effects resulting from long-term (life-time) exposures. As a result, the use of these levels in discussing short-term, infrequent exposures provides an extremely conservative, (ie. protective) evaluation of the potential health hazard. As will be discussed in the following sections, the potential exposures to contaminants related to former WSOW activities will be short-term and infrequent. Comparison values used in the evaluation of these contaminants are described in Appendix B. The following briefly describes the pathways evaluated for contaminants related to U.S. Army operations at the Weldon Spring Former Ordnance Works.

Localized areas of soil contamination have been documented in former production, storage or waste disposal areas, on WSTA and within the conservation areas. Access to contamionated areas within WSTA is restricted to remediation personnel. There is also limited access provided to the U.S. Army Reserve and other military units for training purposes. Training exercises are restricted to areas away from contaminated soil (17). Figure 5 shows the locations of existing training areas and those proposed for 1994, and their relationship to contaminated areas within WSTA. Areas considered for training activities are evaluated for potential contamination exposure to troops. Use for training in these areas is considered only after the areas have been determined safe by the Army and regulators (7). Portions of the conservation areas with extensive localized soil contamination have been fenced. The principal potential receptors of contamination in soils within former WSOW would be trespassers. These individuals would be exposed infrequently for short time periods.

Contaminants have been found in groundwater on WSTA and, to a limited extent, within the conservation areas and offsite. During and after the operational life of the former WSOW, drinking water has been provided by the WSOW (now St. Charles County) Wellfield. Use of onsite groundwater as a drinking water source is currently prohibited. Offsite, public water supplies were provided at the single location where groundwater wells were observed to be contaminated, even though contaminants detected were not at levels of concern (11). Although potential exposures prior to 1988 can not be determined, there is currently no evidence of groundwater contamination in private wells offsite which are monitored by Missouri Department of Health (MDOH) (13, 34).

Very low levels of explosives and metals have been observed in some surface water bodies and sediment. The potential exists for local biota to be exposed to contamination from surface water and sediment or from contaminated soil, although sample data supports that no contamination at levels of concern has been detected in biota collected from the former WSOW (9,45,46). The potential receptors would be hunters or anglers who frequently consume fish and game that could contain contaminants.

Weldon Spring Training Area (WSTA)

The area currently designated as WSTA comprises about 1700 acres of the original 17,00 acres of WSOW. With exceptions which will be described in the following sections, almost all fo the waste areas are located in this 1700 acres. At the peak of operations, during WW II, WSOW consisted of 18 TNT and two DNT plants. Each TNT plant consisted of mono-, bi- and tri-nitration houses, where toluene was nitrated in three stages. Additional processing occurred in the wash houses, where crude TNT was purified with a "sellite" (sodium sulfite) solution. Two sellite production facilities were located in the southern portion of WSTA. Melting, dewatering and recrystallization of TNT occurred in grainer houses. DNT was produced in nitrating houses and sweating houses, where the product was heated in a "sweat pan" to drive off impurities. After purification, molten DNT was cooled to a granular form. The granulated product was screened and packed for shipment. Figure 6 shows the locations of the various former production and waste management facilities at WSTA.

Primary waste products of explosives production process are red and yellow water. Red water is produced during the TNT purification process and consists of water, ash, inorganic salts, dyes and relatively small amounts of TNT. Yellow water is essentially a more dilute form of this waste. Approximately 83,300 feet of buried (2-5 feet deep) wooden pipeline remain at WSTA. Three pipeline systems conveyed red and yellow water from settling tanks at the TNT and DNT production lines to wastewater treatment plants along the southern boundary of the site. A fourth pipeline subsystem carried treated and untreated wastewater from the treatment plants to a final discharge point off site to the southeast, ultimately reaching the Missouri River by surface flow (1).

There are 22 buildings remaining on the WSTA. Of these, 16 are still in use, leaving 6 abandoned buildings (1, 7). There are also extensive remains of partially demolished structures, building foundations, some with open basements, and cisterns, some partially filled with water, throughout the site. The concentrations of soil contaminants occur in and around the remains of the explosives production structures.

The burning grounds at WSOW were used to dispose of TNT products during site decontamination activities. The burning ground on WSTA is designated burning ground five/six. It is located in the extreme southwestern portion of WSTA. All burning grounds are fenced, and are overgrown with brush.

The landfill, located in the north central portion of WSTA, is a 550 by 250 foot area. The landfill is not currently in use. No evidence of recent disposal activity was found during RI activities. It has reportedly been used for Army earth-moving equipment training exercises (1). It is generally flat, with several small, soil-covered piles. The site is vegetated with scrub brush.

The dumps are located in the northeastern and south central portions of WSTA. They are about 12,000 square feet and 34,000 square feet, respectively. Both are vegetated with scrub brush. The southern site was excavated out, re-closed and capped with clay, while the northern site was left uncovered with visible piles of building material and scrap metal.

Seven lagoons were constructed for waste water storage prior to construction of treatment facilities (Figure 7). Of these seven, the four were filled with soil by December 1943, when treatment facilities became operational. Also, two were incompletely filled and still contain variable amounts of runoff water. There were four lagoons on WSTA and three outside WSTA. Lagoon One, to the east of WSTA was earth filled. Lagoon Two, within WSTA was also earth filled. Lagoon Three, located outside WSTA was never filled and contains runoff rainwater. Lagoons Four and Five, on WSTA, were reported to be filled. But, apparently due to settling and erosion, these two lagoons impound variable amounts of runoff rainwater. Lagoons Six and Seven were not filled. Lagoon Six seasonally holds small amounts of water (8). Lagoon Seven to the north of WSTA is currently water-filled and is designated Lake 16.

The contamination of groundwater by ordnance production activities has been known since the first investigation of contamination at WSOW was conducted by the Army in 1943. Contaminated groundwater was traced from the facility to offsite springs. Local springs and surface water tributaries were observed to be contaminated. Five demolition and cleanup actions have been undertaken since the 1940's. These occurred in 1944, 1945-46, 1950-57, 1961-62 and 1967. These actions were undertaken to mitigate the sources of contamination and did not involve activities aimed at cleanup of water contamination (3). In 1976, the Army conducted environmental studies to estimate contamination and contaminant migration, focusing on groundwater pathways. In 1987, The COE was tasked with developing a Remedial Investigation/Feasibility Study (RI/FS) for WSTA (18, 30).

Generally, the highest detected concentrations of contaminants were measured in samples collected from soils and sediment onsite, and groundwater onsite (18, 30). The WSTA RI sampling activities consisted of three phases, conducted from Fall 1988 through Fall of 1989. The first phase assessed surface soil contamination within the TNT and DNT production facilities, wastewater treatment plants, the sellite and acid production plant areas, laboratory buildings, and stream beds exiting the perimeter of WSTA. The second phase assessed surface soil contamination in the troop training facilities, including training areas, firing ranges, access roads, air strip and helipad areas, bivouac areas, office buildings, parking areas and garages. The third phase concentrated on assessing the extent of lead contamination in the production facilities and administration areas (18, 30). A total of 5700 TNT screening samples were collected. More than 1900 soil samples were collected for detailed analyses (18, 30).

RI sampling and analytical activities were conducted for WSTA in 1988 and 1989. RI sampling and analyses were conducted for the remainder of the non-DOE controlled WSOW in 1990 and 1991 (3). During these RI sampling and analysis activities, the primary contaminants discovered were nitroaromatics (2,4,6-TNT, 2,4-DNT, 2,6-DNT, 1,3,5-TNB, and 1,3-DNB), metals, including lead and arsenic, Polychlorinated Biphenyls (PCBs)s, polycyclic aromatic hydrocarbons (PAHs) and asbestos. All soil contaminants appear to be residual contamination from the production or disposal activities. Contaminants are generally limited to the surface and shallow subsurface. The exception to this is the extensive wooden pipeline constructed to transport wastewater to treatment plants (3, 18, 30). Although explosives contaminants were not found in soil samples surveys from pipeline locations, it is anticipated that such contamination will be found during remedial excavation (3).

Surface Soil

Access to contaminated areas onsite is limited to government and contractor personnel involved in remediation-related activities. Occupational Safety and Health Administration (OSHA) and EPA regulations require that remediation workers follow strict safety procedures at NPL sites. It is expected that remediation workers will follow required safety procedures thereby preventing exposure to contaminants during their activities. The U.S. Army Reserve maintains a training program on WSTA. Training activities are currently limited to 200 acres located away from contaminated sites. As areas are determined to be free of contamination, it is anticipated that additional areas will be added for training (36). The remaining possible receptor population would be trespassers who ignore safety measures at WSTA. Exposure of trespassers to these soil contaminants is expected to be infrequent and short-term.

As stated above, access to WSTA is restricted to authorized personnel. The site is fenced to prevent trespassing. For these reasons, contact with environmental media onsite is limited primarily to remediation workers, and secondarily to trespassers who ignore and evade the security and warning measures. Based on information reviewed to date, health risks from nitroaromatics and other contaminants in the onsite soil are minimal. In the conservation areas, soil contamination is concentrated in the burning grounds which are fenced. Contact with contaminated soil in these areas is limited to infrequent incidental contact by trespassers. Health risks associated with incidental contact with contaminated soil in these areas is also regarded as minimal.

The Proposed Plan for remediation for Operable Unit One at WSOW envisions incineration for treatment for much of the soil contamination at the site. Incineration is a remedial alternative which is a concern to members of the public in terms of its safety. ATSDR will review the proposed plans for the remedial alternative chosen. Appendix D presents the ATSDR preliminary evaluation of the incineration alternative.

- Nitroaromatics

Surface soil in production and storage areas is contaminated primarily with nitroaromatics and metals. There are also multiple areas where discarded TNT was burned. Residue from this activity remains in the soil in these areas. Figure 8 shows the location of the various contaminated areas within WSTA (18, 30).

Surface soil samples collected during Remedial Investigation TNT screening surveys in the vicinity of the production plants showed widespread 2,4,6-TNT contamination with concentrations ranging as high as 63,621 mg/kg. The higher concentrations found were associated with the grainer houses and settling tanks. Sampling for other nitroaromatics found more moderate levels of DNT (maximum of 160.0 mg/kg for 2,4-DNT and 8.1 mg/kg for 2,6-DNT), associated with the wash house and grainer house areas. The maximum 1,3,5-TNB (trinitrobenzene) concentration was detected in wash house settling tanks areas at 130.0 mg/kg (18, 30).

The detected levels of 2,4,6-TNT far exceed any ATSDR comparison values (CVs) for soil (20.0 ppm - ATSDR Cancer Risk Evaluation Guides, or "CREG"). The detected levels of 1,3,5-TNB also exceed ATSDR soil CVs (40.0 ppm - ATSDR adult Reference Media Evaluation Guide, or "RMEG"). The levels of 2,4-DNT, 2,6-DNT are below the ATSDR soil CVs for adults (1,000 ppm - ATSDR adult chronic Environmental Media Evaluation Guides, or "EMEG"; and 1,000 ppm - adult RMEG). It must be noted that the comparison values used are extremely conservative and protective of health, in that they are based on the assumption of long-term exposure. The exposures which would occur as described above are short-term and infrequent.

- Metals

Heavy metals and common metals are present throughout the nitration houses and wash houses. Arsenic, cadmium, zinc and thallium were detected above background. However, none were detected at concentrations of concern.

Lead was detected in thirteen of the nitration houses, ranging to 7300 mg/kg. The lead is believed to be residual product of acid reaction with the spark proof lead flooring and cladding used in many of the production facilities. Lead contamination at these levels is an issue in terms of chronic, repeated exposure (20). However, the fencing and warning signs in place at WSTA are sufficient to prevent access by the general public to the areas with lead-contaminated soils. As a result, the lead contaminated soil in these areas is not considered a threat to public health, based on current land use.

- Polychlorinated Biphenyls

Polychlorinated biphenyls (PCBs) were detected in three of the nitration houses, three wash houses, and a waste water treatment area. The maximum concentration for PCBs was 42.0 ppm, in the waste water treatment area. The ATSDR CV for PCBs is 0.09 ppm, based on the ATSDR CREG derived from the EPA cancer slope factor. (The EPA slope factor is a numerical value used in estimating cancer risks in humans.) Exposures which might cause significant negative health effects would need to be greater than the infrequent and incidental exposures which trespassers may experience at WSTA. Therefore, exposures of trespassers to the concentrations of PCBs in soil are not of public health concern, and are not expected to result in adverse health effects.

- Asbestos

Asbestos was observed on the surface of the burning ground and in derelict and razed building sites (1). Surveys were made of numerous sites and the suspected presence of asbestos was noted in a number of derelict structures. No concentrations were presented in RI material. However, within the restricted areas of WSTA, there may be concentrations of asbestos that are health hazards to individuals who may be directly exposed, such as trespassers.

- Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) were also detected in low levels in numerous samples associated with the wash house areas (See Appendix C). Because of the expected infrequency of exposure at WSTA, the acute exposure is the only potential hazard. PAHs generally have low acute toxicity to humans. The CVs which were exceeded in onsite soils are those relating to cancer risk from life-time exposures. Additionally, adverse noncancer health effects associated with non-occupational (short-term, incidental) PAH exposure generally have not been observed in people. Therefore, exposures of trespassers to PAHs in soil are not expected to result in adverse health effects and for this reason are not of public health concern (22).

- Semi-Volatile Organics

Several semi-volatile organics (SVOCs) were found in low concentrations in samples from various areas associated with the production facilities. These contaminants (bis(2-ethylhexyl)phthalate, 1,2-dicarboxylic acid, dibutyl ester (dibutyl phthalate), N-nitrosodiphenylamine) were generally at or below detection levels. The SVOC contaminants were identified in the RI as laboratory contaminants and, as such, are obviously not considered a threat to public health.

Groundwater

The first evaluation of the extent of groundwater contamination was made by Fishel and Williams (1944) (28). Contamination of the groundwater was discovered to be widespread under WSTA and in the surrounding vicinity. Later environmental assessments during the 1950s and 1960s determined that the groundwater in the vicinity of WSTA was still contaminated, but no groundwater quality information was obtained (33). Since the start-up of WSOW and continuing today, drinking water for WSTA has been obtained from what is currently the county well field, located adjacent to the Missouri river south of WSTA. This well field is strongly influenced by water infiltrating from the river. From the well field, the water passes through the county water treatment facility before being distributed to local users, including WSTA (29). Historically, the use of groundwater for consumption on WSTA has been prohibited, and there are no production wells, so that groundwater contamination is not considered a public health threat.

A total of 34 wells in 20 locations within WSTA were constructed to perform the RI sampling activities. Samples were collected from the overburden and shallow bedrock aquifer. As stated in sections above, the delineation of discrete contaminant plumes is precluded by the karstic nature of the aquifers. Sampling and analyses serve to determine the existence of groundwater contamination in the aquifers underlying WSTA and to define the range of concentrations present.

Contaminants associated with the production processes at WSOW were detected in the overburden and in two zones within the shallow bedrock aquifer. Nitroaromatics were detected frequently in the overburden and shallow bedrock aquifers. 2,4,6 TNT was observed at levels ranging up to 51 ppb (31). 2,4 DNT and 2,6 DNT ranged from 0.75 to 69.0 ppb (31). 1,3,5 TNB ranged from 0.75 to 7.3 ppb. The higher concentrations were generally found in the overburden wells. Lower levels and less frequent detections were recorded for the deeper zone of the shallow bedrock aquifer. Cadmium was also detected at levels above EPA's Maximum Contaminant Level (MCL) in samples from all three zones. Cadmium, was also detected at levels above ATSDR CVs. Appendix F presents a summary of the WSTA groundwater contaminants which exceeded ATSDR CVs. Institutional controls enacted by the Army prohibit the use of groundwater on WSTA, so that at present, there are no receptor populations for these contaminants. Offsite wells were sampled as a part of the RI process. Maximum cadmium levels in these wells (0.3 ppb) did not exceed ATSDR CVs (18, 30). Monitoring programs for the St. Charles County Wellfield are in place to monitor for hazardous chemicals (including military-specific compounds) in that water supply (32).

Physical Hazards

TNT and DNT are comparatively insensitive to physical shock, and can even be burned in small quantities without danger of detonation. As a result of these characteristics, it is unlikely that TNT or DNT contaminated soils represent a physical hazard. However, high levels of contamination in large quantities are present in the WSTA wooden sewer pipe system. By-product wastes were piped through 83,300 feet of wooden sewer pipe. During the early production period wastewater was stored in lagoons (3). The pipelines are contaminated with encrusted nitroaromatics in large enough quantities to represent a risk of explosion if they were to be improperly disturbed during remediation.

Additional physical hazards onsite include derelict structures, foundations, basements and cisterns. These derelict structures should be considered to be physical hazards, primarily to site remediation workers. Derelict structures which remain in troop training areas may be considered physical hazards to troops engaged in training on WSTA. It should be noted, however, that the training and missions of both remediation workers and military personnel are such that they are likely to both be aware of these types of hazards and prepared to deal with them. Access to WSTA is restricted to authorized personnel, so that the only members of the public exposed to possible physical hazards would be trespassers. In the case of trespassers, warning signs and fencing are in place to restrict access to protect the public from contact with these and other hazards. Although specific plans are not detailed, the WSOW Final Feasibility Study (FS) mentions clearing of these potential hazards as a part of the remediation process (6).

Conservation Areas

As stated previously, "the conservation areas" in this document are defined as portions of the original ordnance production facility not now controlled by the Army or DOE. Visitors to the conservation areas are the most likely people to be exposed in the these portions of former WSOW. As the following information shows, the possibility for a completed pathway is extremely limited in the conservation areas. Additionally, visitors are usually in these areas infrequently and generally for only a short period of time, so that any exposures which might occur would be limited.

A number of the remaining structures in the former WSOW outside DOD and DOE controlled areas are currently operated by MDOC and St. Charles County Water Department. No contaminants were detected in RI analyses from samples taken in the vicinity of these structures (See Figure 6)(1).

There are also a number of derelict structures remaining on conservation areas. The majority of these are former storage bunkers, located in the Busch Area. The three production areas outside the Army and DOE areas were dismantled and the foundations covered with soil to eliminate physical hazards (1).

Mechanical City, the construction and maintenance center for WSOW is located just south of WSTA. The area once contained 10 buildings. These have been demolished, leaving only foundations and fire hydrants. A large amount of construction debris remains in this area (1).

Several former disposal facilities for WSOW are located outside the present boundaries of DOD and DOE controlled areas. These include six burning grounds, three wastewater lagoons, and a dump. The dump is not a formal WSOW disposal area, but reportedly contains a small amount of construction debris. The burning grounds show variable amounts of burned debris. Lagoon 7 (Lake 16) is currently filled with water and is used for catch and release fishing. Lagoon 6 is seasonally filled with ponded water and is not frequently used for recreational purposes.

Springs sampled within WSOW have been shown to be contaminated with nitroaromatics. However, groundwater and groundwater-fed springs are not used as a drinking water source for the conservation areas. Contact with contaminated spring water is a possible pathway of concern, although such contact is not a frequent occurrence. Institutional controls placed on groundwater use in the conservation areas have eliminated it as a source for drinking water, so that at present groundwater does not represent a completed pathway.

Access to soil-contaminated areas in the WSOW is restricted. Contaminated areas are fenced, posted. Maps delineating contaminated areas on conservation lands are available at the Conservation Area Information Center.

One possible pathway to be evaluated is the former explosives wastewater lagoon #7, which is now a stocked fishing pond on the August Busch Memorial Conservation Area. For fisheries management purposes, the state of Missouri has placed catch-and-release restrictions on use of this lake, effectively minimizing exposure through the consumption of any potentially contaminated fish from this source.

Consumption of contaminated game is a very limited issue in the conservation areas. Contamination of soil and surface water is very limited and the potential for exposure of game animals is also very limited. However, since there is even the limited potential that these animals may be exposed to contamination within WSTA and then could move into the conservation areas and offsite, this document evaluates this potential pathway. Also, some degree of bioaccumulation in game animals could occur through consumption of onsite contaminated water. However, the most contaminated areas are not vegetated and are not attractive grazing areas. Therefore it is not likely that they would be sources of exposure for deer. Limited evaluations have been made regarding contamination of fish and game at WSOW. However, more detailed work at similar sites is available for comparison. This information is discussed in later sections.

Surface Soil

The existence of former production, storage and waste disposal facilities within WSOW but outside the Army and DOE controlled areas (See Figure 6) necessitated extensive environmental sampling and analyses in the former WSOW. Access to these areas is restricted by fencing and therefore contact is unlikely. Contamination localized in these areas has been documented in RI sampling and analytical activities. Similar to WSTA, the contaminants of interest are nitroaromatics and metals. The following sections summarize the evaluation of data collected from specified areas.

- Nitroaromatics

More than 2100 surface soil samples were collected and analyzed during TNT screening activities. Sampling activities were concentrated on the burning grounds, around bunkers and at former sites of the three regraining facilities. A detection limit of 5.0 ppm was established for these samples (1). ATSDR has established a CREG comparison value for TNT of 20.0 ppm based on EPA lifetime cancer risk slope factor calculations. The ATSDR EMEG for ingestion of soil by a child is 30 ppm. This comparison value accounts for daily human exposure to a chemical that is likely to be without noncarcinogenic effects over a specified duration of exposure to include acute, intermediate, and chronic exposures. Based on these criteria, the 5.0 ppm detection limit should be sufficient to detect TNT concentrations which might be a human health threat. The WSOW RI depicted the screening test results in incremental categories of <5 ppm, 5 to 10 ppm, 11 to 100 ppm 101 to 1000 ppm and >1000 ppm. For the purposes of this evaluation any detections in the 11 to 100 ppm range or greater are considered to be of possible concern.

The burning grounds were the only facilities screened in which contaminants were found. Many of the detections were sufficiently high to be of concern. Figure 9 depicts the locations of the burning grounds. Burning ground 1, with a total of 200 samples collected had 30 samples with TNT concentrations of 11.0 ppm or greater. The highest concentration was 510,632 ppm. Burning ground 2, with 170 total samples, had five samples with greater than 11.0 ppm TNT. The maximum concentration was 3,513 ppm. Burning ground 3, with 146 total samples, had seven samples above 11.0 ppm TNT. Here, the maximum concentration for TNT was 2,966 ppm. Burning ground 4 had 25 samples, with none exceeding 11 ppm. Burning ground 7, with 110 samples collected, had eight which exceeded 11 ppm. The maximum concentration in this area was 11,414 ppm of TNT. Burning ground 8 had 72 samples collected, with none above the detection limit. The dump had a total of 106 samples collected, with one in excess of 11 ppm TNT concentration. That sample measured a TNT concentration of 30 ppm (1).

At present, institutional controls in the form of fencing and warning signs restrict public access to the burning grounds, and serve to prevent exposure to any members of the public except for determined trespassers. Burning ground 1 presents the most substantial risk both in terms of the number of detections at levels of concern, and in terms of the high concentrations of TNT present. Burning ground 1 also contained one sample in which 2,4 DNT was measured at a concentration of 7,100 ppm, well above the ATSDR comparison values. The remaining three areas, burning grounds 2,3, and 7 had proportionally fewer samples in excess of levels of concern. However, the maximum concentrations were high enough that these areas should be evaluated to determine the extent of the hotspots.

- Metals

The metals sampled for during WSOW RI activities are arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver. As with nitroaromatics, sampling activities concentrated on the areas surrounding former WSOW facilities (1). Lead was the single metal detected at levels of concern. ATSDR is currently using a level of 500 ppm as the comparison value (CV) for lead in soils (20). Isolated soil samples at bunkers designated B24-03 and B50-3 exceeded the ATSDR CV (667 and 949 ppm, respectively) (1). These samples were collected from small areas (about one foot in radius) surrounding drains at these bunkers. The drain lines originate inside the bunkers, and serve to collect seepwater and condensation from the bunkers. The source of the lead is unknown, but it is believed to be from accumulations of trash and debris as well as expended recreational firearm rounds (21). Samples collected from burning ground 1 exceeded the ATSDR CV in several instances. Where concentrations exceed 500 ppm, the EPA Proposed Plan for Soils calls for stabilization and landfilling (31).

Groundwater

The karstic nature of the subsurface geology is such that it is not possible to trace groundwater contaminant plumes off of WSTA with any accuracy. However, in general terms, groundwater flow can be roughly correlated to surface water drainages. The surface water drainage divide runs approximately east-west through the center of WSOW. In the northern half, surface water flows north. In the southern portion of the site, the flow is generally to the south. Detection of low levels of nitroaromatic contaminants are seen in analyses of groundwater within the WSOW boundaries (10). The levels found are below ATSDR CVs. Additionally, as is the case with WSTA, drinking water has been and is currently supplied by the St. Charles County Wellfield, so that consumption of contaminated groundwater is not generally a concern.

Springs sampled within the former WSOW have been shown to be contaminated with nitroaromatics, although at concentrations generally below ATSDR comparison values (18, 30). Contact with contaminated spring water is a possible pathway of concern, although such contact is not a frequent occurrence.

Isolated springs were sampled during the spring of 1989 in which 2,4,6 TNT exceeded ATSDR CREG CV of 1.0 ppb. The five springs had 2,4,6 TNT concentrations ranging from 1.6 to 3.0 ppb. Concentrations of contaminants detected during low flow periods did not exceed ATSDR CVs (18, 30). The EPA has issued a Health Advisory for TNT. The recommended drinking water equivalent level for the per-day lifetime (70 year) exposure for a 10 kilogram child is 0.02 mg/L, or 20 ppb (19). In view of the low probability that people would drink the water from these springs, and the greater improbability that any one person would frequently drink this water, these springs should not be considered a threat to human health.

Biota/Foodchain

Land-use restrictions and health and safety requirements for site workers have minimized the potential for human exposure to contaminants onsite. However, under current conditions, biota may be exposed to contamination in soils, sediments, and surface water. Although access by the general public to WSTA is restricted, it is possible for game and waterfowl to move through contaminated onsite areas as part of their ranging territories. Game animals may consume site-related contaminants through ingestion of contaminated soil, plant material that has taken up contaminants from the soil, from ingestion of contaminated surface water, and possibly, from contaminated dust on forage. Additionally, fish may be exposed to and take up contaminants from affected surface water or sediment.

Comprehensive game and fish take information is not currently available for the Busch Conservation Area. However, such information is available for the adjacent Weldon Spring Conservation Area. If the per-person usage is similar between the two areas, assumptions can be made concerning the numbers of game and fish collected by the public.

The Missouri Department of Conservation estimates that, based on surveys, in a one-year period of 1989-1990 558 squirrels, 283 rabbits, 89 deer, 93 doves, 146 ducks, 8 quail and 1 turkey were taken by hunters from the Weldon Spring Conservation Area. Weldon Spring anglers kept a total of 7,232 fish. Of this total there were 2,702 catfish, 1,970 buffalo, 722 freshwater drum, and 527 bluegill. The remainder were carp, largemouth bass, crappie, walleye, striped bass, and sunfish. According to the Missouri Department of Conservation, these fish were caught by a total of 3,603 anglers (26). Creel surveys are available for Lakes 34 and 35 at Busch Conservation Areas. The 1993 survey of Lake 34 depict a similar diversity of species, with a total of 2,871 fish, caught and kept by 4,686 anglers. The total estimated weight of these fish is 1,380 pounds (lbs), or approximately 0.29 lbs per angler. The 1992 survey for Lake 35 estimated a total of 5,376 fish caught by 9,186 anglers. The total weight of this catch is estimated at 2,316 lbs. The average weight of catch per angler for this lake is about 0.25 lbs (25). It is probable that these totals are representative of the catches that occur at other lakes in this area, and that the average amount of fish per angler is similar for the other fishing lakes. What is implied from this information and from informal observations by state officials (27), is that there is little or no subsistence fishing occurring in the conservation areas. Therefore, fish from these lakes are apparently not consumed by the public on a regular and frequent basis.

Food chain exposure pathways include the consumption of animals that have been exposed to and could have bioaccumulated contaminants. Chemicals such as metals can accumulate in tissues of certain organisms at levels higher than the chemicals' concentrations in water, sediment, soil, or vegetation. An evaluation of the effect on fish and game is important, since, as the following information suggests, exposure of biota to contaminants may be occurring.

- Fish

Low levels of explosives contamination have been documented for several surface water bodies in the Busch and Weldon Spring Conservation Areas (1). Contaminant levels are depicted in Table 2.

Water samples were collected from 18 lakes and two (former) lagoons in the conservation areas. Sediment samples and/or cores were collected from each of the lakes and three lagoons (#1, #6, and #7). Of the 18 lakes sampled, six (Lakes 10, 23, 32, 35, 36) had detectable levels of nitroaromatics in surface water (1). Detections are listed in Table 2. Lakes in which no nitroaromatic contaminants were found include; 2, 4, 7, 8, 10, 20-22, 24, 32-34, and the unnamed lake south of Hampton Lake. Locations of the conservation area lakes and lagoons are shown in Figure 10.

Lagoon 6 was the only one of the lagoons with water samples that had detectable levels of nitroaromatics (0.07 ppb o-nitrotoluene). No nitroaromatic contaminants were detected in lagoon 7 (Lake 16). Sediment sample analyses revealed no nitroaromatics at the detection levels (1). Numerous metals were detected in sediments at varying levels. Lake 4 had the only water sample in which state of Missouri drinking water standards were exceeded. The metal of concern in Lake 4 was selenium, with a concentration of 0.11 ppm. Of sediment samples, only Lake 16 had metals in excess of state sediment standards (arsenic at 0.053 ppm) (1). Additionally, sediment samples collected from streams exiting WSTA documented very low, localized concentrations of nitroaromatics, metals and SVOCs(18, 30). The contaminant levels found are well below levels which might be of concern in terms of human consumption or contact.

Although exposure via consumption of surface water is not a threat, the effect of these levels of contaminants on fish is a concern expressed by the public (See Community Health Concerns section). Consumption of nitroaromatic-contaminated fish is a concern if the fish contain relatively high levels of contaminant or as the result of long periods of frequent consumption of contaminated fish. Studies have been conducted to determine the extent to which fish bioconcentrate nitroaromatic contaminants (41,42). From these studies, it is possible to use the levels of contaminants found in water to roughly estimate the amount of fish which would have to be consumed to pose a potential threat. At the levels of contaminants found in the area lakes, using the most protective assumptions, it is projected that consumption of contaminated fish would have to occur on a daily basis for a period of years (43). To date, fish taken from these lakes have not been analyzed for nitroaromatics contamination. However, based on the low levels of nitroaromatic contaminants detected in water it is unlikely that fish would be contaminated at levels of concern.

In 1988 DOE contractors collected fish from lakes 34-36 in the Busch Conservation Area, and lake 37, an offsite lake considered to represent background. Whole, cleaned fish (scaled, beheaded and eviscerated) and fillets were composited and analyzed. These samples were prepared to represent the edible portions of the species collected. These samples were then analyzed for metals.

The analyses were reviewed by ATSDR in 1989. ATSDR Emergency Response Branch wrote a health consultation at the request of EPA Region VII on "Fish Data, Weldon Spring Site, St. Charles County, Missouri" (45). The consultation evaluated the potential public health hazard of contaminants present in the composite fish samples. Metals of concern were mercury, lead and arsenic. Mercury was detected in fish samples from all four lakes at levels ranging from 0.16 to 0.27 ug/g (ppm). Fish from lake 37 contained 0.23 ug/g of mercury. Lead was found in fish at 4.0 ug/g in lake 34 and 4.2 ug/g in lake 36. Arsenic was detected in fish at 13.9 ug/g in lake 35 and 13.6 ug/g in lake 37.

Lead in fish taken from lakes 34 and 36 presents an increased potential for adverse lead exposure to children and pregnant women who regularly and frequently consume the contaminated fish. However, the lead in these composite fish samples is not a public health threat to area residents who have occasional fish meals from locally caught fish. Arsenic found in fish is usually in an essentially nontoxic, organic form. Without speciating the metals it is not possible to determine conclusively the toxicity of the arsenic in these fish. In any event, the possible adverse effect would be greatly reduced if consumption of fish from this lake is limited.

EPA contractors collected and analyzed additional fish samples from Lake 36 in June and November of 1992 (46). Whole fish and fillet samples were analyzed for lead, mercury and arsenic, with detection limits of 0.1 mg/kg (ppm). Arsenic was not detected. Lead was detected in whole fish samples at a maximum concentration of 0.176 mg/kg. Mercury was detected in fillet samples at a maximum concentration of 0.212 mg/kg. The lead level is noticeably lower than those detected in the 1988 study. The level for mercury was similar to those found in the 1988 study. ATSDR evaluated the results of this study in 1993. The consultation concluded that these levels were not a concern for either infrequent or subsistence consumption (49). Additionally, the MDOH considers lead levels above 0.3 ppm to justify a no-consumption fishing advisory. Based on the decrease in lead levels from the 1988 analyses to the 1992 analyses, the MDOH does not feel that an advisory is necessary for these lakes (50).

- Game

Little information has been collected regarding bioaccumulation of contaminants in animals commonly hunted in the conservation areas. However, a 1988 study by DOE contractors did evaluate the possible extent of radionuclide and metal contamination in squirrels and rabbits (9). Analyses of these samples found no significant accumulation of contaminants (9). This and subsequent DOE studies will be evaluated in the public health assessment being completed for the DOE site. As stated earlier, the areas heavily contaminated by nitroaromatics are not vegetated and are not attractive to grazing animals. For this reason, the opportunity for exposure to game animals is lessened.

A recent study, undertaken by the U.S. Army Environmental Hygiene Agency at the Joliet Army Ammunition Plant, Wills County Illinois, evaluated the bioaccumulation of chemical contaminants in deer (38). This study focused on explosives contaminants present at a munitions production facility and is therefore useful in the assessment of the effect on these contaminants at WSOW. Contaminants of concern in the Joliet study were; metals, PCBs, and explosives, including TNT, DNT, DNB and TNB. Concentrations of these chemicals in environmental media varied widely across the site. However, because of the similarity of production facilities and products, the ranges of concentrations found at Joliet were comparable with those found at WSTA.

Samples were collected of deer muscle, liver, kidney, bone and fat. The study found that there did not appear to be any appreciable bioaccumulation of nitroaromatics in these tissues. There was, however, an accumulation of low levels of arsenic thought to come from natural background levels in the soil.

The Joliet study also cited two other Army studies on bioaccumulation of nitroaromatics in game animals. Evaluations were performed on samples collected at the Alabama Army Ammunition Plant, Childersburg, Alabama (40), and the Badger Army Ammunition Plant, Baraboo, Wisconsin (44).

The study conducted at the Alabama facility assessed the bioaccumulation of TNT in deer, rabbit and quail. It was found that TNT did not accumulate at a level above the 0.2 mg/kg detection level (40). The study conducted at the Wisconsin facility assessed bioaccumulation of DNT in deer tissue. It was found that DNT did not accumulate in the animals sampled above the 0.1 mg/kg detection level (44). For comparison, ATSDR CVs for TNT, 2,4-DNT, and 2,6-DNT in drinking water are 1.0 mg/kg, 20.0 mg/kg, and 400.0 mg/kg. Based on the information provided by these three studies, and assuming that former explosives production are similar in their relevant characteristics, consumption of game animals from the conservation areas is not a public health threat.

Physical Hazards

A number of derelict structures remain on the former WSOW outside Army and DOE controlled areas. The majority of the remaining structures are former storage bunkers, located in the Busch Area. Of the 100 total bunkers existing on the site, nine are used by the state for storage and are locked. A total of 76 of the bunkers are empty and have been sealed by the state. Fifteen remain open but are empty.

Additionally, a large amount of construction debris was found in Mechanical City, the construction and maintenance center for the former WSOW located just south of WSTA. Although it is recognized that the general public seldom visits the southern portion of the former WSOW, this debris may still constitute a physical hazard.

Offsite

The primary concern regarding contaminants emanating from the WSTA is that of groundwater contamination. The following is an evaluation of the probable extent of contamination in this medium.

Groundwater

The predominant source of drinking water for the residents in the vicinity is the St. Charles County Wellfield, located in the Missouri River floodplain to the south of WSTA. Water is obtained from Missouri River alluvium and from the bedrock aquifers. Based on the proximity of the wellfield to the Missouri, a major source of water is infiltration from the river. Residents to the northeast of the former WSOW receive water from St. Charles County Water Supply District #2.

The karstic nature of the subsurface geology is such that it is not possible to trace groundwater contaminant plumes into offsite areas with any accuracy. However, as stated earlier across the northern portion of the WSOW and adjacent area, surface water flows north. In the southern area, the flow is generally to the south. RI environmental sampling and analysis document that contaminants in trace amounts in groundwater have migrated offsite as described below.

According to information provided by army and state investigations, the only location where any occurrence of explosives contaminants has been found in drinking water is the Twin Island Lake Resort (4, 18, 30, 13, 34, 35). Established in the 1950's, today the resort has about 175 trailer campsites and about 50 sites for tent camping. About half of the trailer sites are occupied year round. The average daily population at the resort varies for about 250 to about 675 over the course of a year. A fishing lake is supplied by springs within the lake (4). In 1988, five of the six wells at the resort were found to be contaminated with explosives (see Table 4). Until 1989, drinking water, as well as water for the swimming lake, were provided by groundwater wells. There was no treatment for any of the water sources. People were exposed to very low levels of explosives via ingestion, inhalation and dermal contact with contaminated well water. The duration of exposure is unknown. The well water was not tested for nitroaromatics until the state of Missouri developed the technology and procedures for accurate testing in 1988. As a precaution to protect the health of resort visitors, the COE began providing drinking water in 1989. In April of 1991, water lines were installed and water is currently provided by the local water district. Subsequent to the initial sampling for nitroaromatics in 1988, nitroaromatic contaminants have not been detected (10). Table 3 summarizes the groundwater usage at Twin Island Lake Resort.

The state of Missouri tested the Twin Island Lake wells for explosives in 1988. The Kansas City District Army COE sampled in 1989. Five of the six wells used for drinking water were sampled. The state of Missouri sampling revealed trace levels of 2,4-DNT and 0.17 - 0.19 ppb of 2,6-DNT, well below the ATSDR CV. COE sampling revealed explosives contaminants in 3 of 4 wells sampled (4). See Table 4 for a summary of the analyses. ATSDR comparison values were exceeded in samples from Wells #1, #3 and #61 for 1,3,5-TNB. Well #3 is the supply well located closest to Weldon Spring. Wells #1 and #61 are connected and located adjacent to each other north of #3, on the western portion of the resort. The levels of TNB found in these wells during this sampling round exceed ATSDR's RMEG CV of 0.5 ppb. The RMEG is derived by ATSDR from the EPA oral Reference Dose. It is a very conservative estimate of the concentration in water or soil at which daily long-term human exposure is unlikely to result in adverse noncancerous effects. Additional discussion of the health effects of TNB can be found in Appendix E.

In 1989 the drinking water pathway was eliminated when the resort began receiving bottled water from the U.S. Army. The resort is currently supplied by a water line from the St. Charles County Public Water Supply District #2, installed by the Army in April of 1991 (36). More recent sampling has not detected the presence of nitroaromatic contaminants in these wells (10). Additionally, incidental dermal contact and inhalation of water from the swimming lake and goldfish pond is not a problem, since no contaminants have been detected in recent sampling.

Thus far, no other occurrence of nitroaromatics have been found in any other drinking water wells in the vicinity of WSOW. The Missouri Department of Health continued to monitor private wells for nitroaromatics until 1992. Since that time wells have been monitored on a quarterly basis for other contaminants, with the emphasis being on radionuclides from the DOE sites and on metals (13, 34). No contaminants have been detected at levels of concern. These data will be thoroughly evaluated in the public health assessment being completed for the DOE facilities at Weldon Spring. The St. Charles County Water Department monitors municipal wells south of the Quarry for site-related contaminants (37).

Quality Assurance and Quality Control (QA/QC)

The contaminant values recorded in this public health assessment are based upon the data developed for and provided by the Department of the Army and the EPA. The most recent RI reports (1,18, 30) describe quality assurance/control measures consistent with usual and acceptable standards in effect at the time the reports were prepared. Documents prepared by EPA, the Department of the Army or their agents reflect, as stated or implied, such standards and practices.

Sampling and analytical procedures used by the state of Missouri followed EPA Contract Laboratory Procedures (CLP) requirements (39). The data provided by state of Missouri also meets acceptable quality control standards and practices.

PUBLIC HEALTH IMPLICATIONS

Toxicological Evaluation

A person is exposed to a contaminant only if the person breathes, eats, or drinks a substance containing the contaminant or by skin contact with a substance containing the contaminant. Several factors determine the health effects of an exposure. These factors include the concentration of the contaminant, the frequency or duration of exposure, the route or pathway of exposure, and the possibility of exposure to a combination of contaminants. Once exposure takes place, characteristics such as age, sex, nutritional status, genetics, lifestyle, and health status influence how the individual absorbs, distributes, metabolizes, and excretes the contaminant. The combination of these factors determines the health effects that could result. Once these factors have been evaluated, it is possible to decide whether there is truly a completed environmental pathway which could result in significant public health concern.

No current completed pathways have been found for contaminants resulting from past ordnance production at the former WSOW. No evidence exists of any public health problems from any potential past exposures. Although exposure levels prior to 1988 can not be determined, the nitroaromatics detected in the Twin Island Lake wells were not at levels high enough to present a hazard to public health. However, for information purposes Appendix E provides brief toxicological evaluations of the contaminants discussed.

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 since 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-supported 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). As a part of the public health assessment for the DOE facilities, additional evaluations will be made of health outcome data to further define occurrence of specific cancer incidence.

Community Health Concerns

The following concerns have been identified by ATSDR through meetings, correspondence, and telephone conversations. The sources of these concerns include citizen groups, governmental agencies, and individual residents. Concerns include those which relate to the specifically to the Army NPL site or which may be overall concerns related to both NPL sites. Concerns specifically related to the DOE portion of the Weldon Spring facilities are not addressed here, but will be addressed in a separate public health assessment. The following concerns are not listed in any order of frequency or significance.

  • Past and current exposure to areas of WSOW outside WSTA soil contamination by hunters, campers, and hikers in the adjacent conservation areas;

    As summarized in the Environmental Contamination section above, offsite soil contamination is not a serious hazard to visitors to the conservation areas. Soil sampling and analyses have confirmed that contamination at levels of concern in the conservation areas are limited to fenced areas that are not accessible to visitors to the recreation areas. During the soil surveys, TNT was reported in several of the samples collected in the bunker areas. Isolated samples from the Busch area and in the vicinity of the school/box factory were also found to have low levels of TNT contamination (1). In all cases these, detections do not represent contamination at levels which would be a threat to public health.

  • Ingestion of contaminants that have bioaccumulated in fish and game from the conservation areas and the Little Femme Osage Slough;

    This issue is addressed in some detail in this document. The reported and projected contaminant levels in fish from the conservation areas is low enough that occasional consumption should not be considered a public health hazard. Currently, water and fish sample analyses information for Little Femme Osage does not exist. DOE is undertaking an analysis at present. Information from this analysis will be incorporated in the upcoming public health assessment addressing the DOE facilities. Additionally, ATSDR is recommending that additional fish samples be collected for analysis of metals contamination.

  • Contamination of private wells by toxic substances migrating from the Weldon Spring Training Area and Chemical Plant Sites;

    The only offsite wells that have been documented to be affected are those at the Twin Island Lake Resort. The wells in the resort are only minimally affected and public water is provided as an additional safety measure. Current monitoring by the state of Missouri did not reveal the presence of contaminants at levels high enough to be considered a public health hazard. The most recent sampling has not detected nitroaromatics in well water at Twin Island Lake Resort.

  • Potential releases of toxic substances from the Weldon Spring waste storage cell as a result of earthquakes or karst dissolution and collapse in underlying limestone terrain;

    The CERCLA Feasibility Study (FS) describes the remedial procedures considered for a "Superfund" site (6). These procedures are subjected to critical engineering and environmental review to ensure suitability. The review process should include an examination of the suitability of these facilities based on the expected local and regional geological stability. RCRA hazardous waste landfill requirements specify that construction take into account the geologic character of the proposed site. At present the location has not been delineated for a landfill. ATSDR will review the documentation provided to evaluate the effect on public health that might occur as a result of the remedial activities. The geotechnical stability of any hazardous material landfill facility at WSOW will be a consideration.

  • Potential remedial worker exposures to asbestos and other hazardous materials due to insufficient worker training;

    EPA requires that the remediation Health and Safety Plan assure that Occupational Safety and Health Administration (OSHA) regulations be followed for the protection of remedial workers. Remedial coordinators will be onsite to monitor remediation activities to assure that safety standards are followed.

  • Potential site hazards due to localized concentrations of explosives materials at the Former Ordnance Works;

    This document addresses the concerns related to explosives contamination. Institutional controls have restricted (if not totally eliminated) access by the public to areas within the conservation areas and on the WSTA which have significant levels of contamination. Localized high concentrations are not a danger in terms of accidental detonation, since even the pure product is extremely insensitive to physical shock. The contamination in the waste system pipelines is a concern in terms of accidental detonation only if improper removal techniques are used. Additionally, the Remedial Investigation provides extensive information regarding the locations of explosives materials at WSOW. With this information EPA, the Army and the state of Missouri provide measures which are protective against hazards posed by such contaminants.

  • Construction of an on-site incinerator to dispose of hazardous materials;

    ATSDR will review the incineration activity plans to determine the extent to which these activities address protection of public health. Additionally, the EPA remedial process at NPL sites provides for the evaluation of remedial technologies being considered. At the time alternatives are presented, the opportunity is given to review and comment. During the operation of any chosen technology, monitoring activities are required by law to ensure that the process is safely conducted. ATSDR has reviewed the Feasibility Study and Proposed Plan for soil remediation procedures. This evaluation is provided in Appendix D of this document.

  • There is specific concern over the number of childhood leukemia cases in the Weldon Spring area;

    In the "Report on Childhood Leukemia in St. Charles County (1970-1983)"(14), the Missouri Department of Health determined that there was no geographic clustering of leukemia in St. Charles County. The study did not find any environmental commonalities, such as water supplies, among the occurrences of leukemia. It is further noted that the reported cases did not appear to have any specific common cause or causes. In view of these findings, and since there have been no documented exposures, no causal link can be determined between contamination resulting from ordnance production activities at WSOW and the occurrences of childhood leukemia in the area. Further evaluation of leukemia will be conducted for the DOE facilities public health assessment.

    A fact sheet on St. Charles County Childhood Leukemia published by the Missouri Department of Health (April, 1994) indicated that total childhood leukemia incidence and mortality rates for St. Charles County are not significantly elevated relative to (or - "greater than") state-wide rates. ATSDR is currently conducting discussions with the Missouri Department of Health to conduct a comprehensive analysis of WSSRAP site-related contaminant distribution and occurrence of specific cancer incidence.

  • Some crops are grown on areas adjacent to site owned by University of Missouri and there is some concern that these crops may be contaminated by site-related hazardous materials and consumed by people;

    The crops in question are those in the conservation areas, planted largely for wildlife or livestock consumption. Soil contamination outside the restricted areas is not a problem. Additionally, groundwater is not used for irrigation of these crops, so contaminants would not be introduced by that means.

  • During the July 1994 Public Availability Sessions, the question was asked whether cases of childhood alopecia might be the result of exposure to chemical contaminants present at WSOW.

    No completed exposure pathways to WSTA contaminants have been documented, including the area in which the alopecia occurred. Additionally, no causal links are known to exist between explosive ordnance chemicals and alopecia (47,48).

DOE Site-related Questions

Questions relating to contaminants potentially resulting from operations at the DOE facilities at Weldon Spring will be addressed in a separate public health assessment.


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