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PUBLIC HEALTH ASSESSMENT

LOUISIANA ARMY AMMUNITION PLANT
DOYLINE, WEBSTER PARISH, LOUISIANA


SUMMARY

The Agency for Toxic Substances and Disease Registry (ATSDR) has prepared this public health assessment to evaluate the potential for contamination from the Louisiana Army Ammunition Plant (LAAP) site to cause harm to people working at or living near the facility. Following a detailed review, ATSDR finds that the LAAP site poses no threat to public health.

The LAAP site occupies approximately 14,974 acres in Doyline, Webster Parish, Louisiana. The government-owned, contractor-operated facility was activated in 1941-1942 for loading, assembling, and packing military munitions for the U.S. Army (Army) in support of national wartime efforts. All production and loading of ammunition operations ended in October 1994. Valentec Systems, Inc., currently oversees/operates the facility under modified caretaker/partial standby status, and several tenants occupy portions of the plant's property.

As a result of former operations, chemicals have inadvertently been released to the environment. LAAP began investigating areas suspected of soil contamination in the early 1980s under the Department of Defense's Installation Restoration Program. Some contamination also migrated through the soil to the underlying shallow groundwater or drained into nearby surface water. Principal site contaminants are explosive compounds associated with munition production and volatile organic compounds (VOCs). The U.S. Environmental Protection Agency (EPA) added LAAP to the National Priorities List (NPL) of sites to be investigated on March 31, 1989, primarily due to concerns about groundwater contamination from the Area P pink water lagoons . The NPL is part of EPA's Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as "Superfund."

Through its public health assessment (PHA) process, ATSDR conducted a site visit and met with representatives from LAAP and the Army. At the time of the visit, ATSDR did not identify any hazards posing immediate threats to public health. ATSDR determined, however, that additional information was needed for a more complete evaluation of ways in which people could have been exposed, or could be exposed, to contaminated media and to explosive compounds and VOCs in the groundwater and nearby streams. ATSDR addresses these issues in this document.

After evaluating environmental monitoring data and key potential exposure situations, ATSDR determined that potential exposures associated with groundwater, surface soil, surface water/sediment, and biota at LAAP do not pose past, current, or future public health hazards:

Contamination in groundwater poses no public health hazard. The shallow groundwater beneath certain areas of LAAP has become contaminated with explosive compounds. No exposure to groundwater contaminants has occurred or is expected to occur in the future because the contaminated shallow groundwater underlying LAAP has never been used as a source of drinking water for the plant, nor is it intended for public use in the future. LAAP has received its water from the deep, uncontaminated aquifer, which is routinely tested to ensure that it safely meets federal and state drinking water standards. Most people at the plant, however, currently drink bottled water. Low levels of explosive compounds were detected one time in drinking water wells for Doyline and the Community of Goodwill in 1989. Residents possibly exposed to the low levels of explosive compounds from ingesting drinking water are not expected to develop ill effects. Explosive contamination has not been reported during regular repeat testing (1989-1993, 1999, and 2001) of the affected wells. LAAP will continue to monitor groundwater movement from the site and off-site groundwater quality to identify and diminish the threat of potential health hazards. No information is available for private wells possibly located in areas where trace levels of contamination migrated beyond the site's southern boundary. Any exposure at trace levels is expected to be below levels of health concern.

Contamination in surface soil poses no public health hazard. Certain areas of LAAP contain high levels of explosive compounds and chromium in surface soil. A patrolled perimeter fence and gated entrance largely prevents public access to these contaminated areas. Although workers or trespassers (such as non-authorized hunters) may have come in contact with contaminants in surface soil, contact was likely infrequent and brief. Intermittent contact with surface soil contaminants, even at the highest levels reported, is not expected to pose a health concern. Access restrictions and land use controls will help to prevent potential future exposures to soil contaminants.

Contamination in surface water and sediment of the local streams poses no public health hazard. Contaminants from LAAP's former operations migrate in groundwater toward and discharge into local streams, such as Boone Creek, Caney Creek, and an unnamed ditch. Some contamination also may have reached the streams in surface water runoff. Public access to the streams is limited at best. Although there is no evidence of people wading or playing in or near the streams, any exposure is likely to be infrequent and of short duration. Such limited exposure with contamination in the waterways is not expected to pose a health concern. Contaminant levels are expected to further decrease by natural degradation processes and with distance from the former source areas.

Consumption of locally caught fish and deer poses no public health hazard. Local residents fish along Bayou Dorcheat and Clarke Bayou, which border the LAAP property to the east and west. Fish from the bayous have not been tested for possible uptake of site-related contamination. Despite this data gap, bayou fish probably have not accumulated unhealthy levels of LAAP-related compounds because only low levels of surface water contaminants have entered the bayous and explosive compounds do not typically accumulate to high levels in fish. Seasonal deer hunting is permitted at LAAP. Information suggests that explosive compounds, such as those concentrated in areas of LAAP, do not typically accumulate to harmful levels in deer tissue, or in other wildlife. Considering this information, ATSDR concludes that fish from Clarke Bayou or Bayou Dorcheat and venison from the LAAP should be safe foods to eat.


BACKGROUND

Site Description and Operational History

The Louisiana Army Ammunition Plant (LAAP) is a government-owned, contractor-operated facility located on 14,974 acres in Doyline near Shreveport, Webster Parish, Louisiana. LAAP is bordered on the north by Interstate 20 and U.S. 80 and by Route 164 to the south. The Dorcheat Bayou, a perennial body of water, forms the eastern boundary, and Clarke Bayou, a small stream, borders the plant to the west (see Figure 1).

LAAP was activated during 1941-1942 when the Silas Mason Company built eight ammunition lines and one ammonium nitrate graining plant at the property for loading, assembling, and packing military munitions. The site was also used to manufacture metal ammunition parts for the U.S. Army (Army). Production at the facility ended in August 1945 at the conclusion of World War II, at which time the site was placed on standby status (Woodward-Clyde 1994).

Under contract with the U.S. government, Remington Rand, Inc., reactivated the facility in 1953 to support the Korean Conflict. After the conflict ended in 1958, the facility was once again placed on standby status. With Sperry Rand as the operating contractor, the site was reactivated to support munitions needs for the Vietnam Conflict in 1962-1974. The Thiokol Corporation then operated the facility until 1996, after closing all production and loading of ammunition operations in October 1994. Valentec Systems, Inc., currently oversees/operates the facility under modified caretaker/partial standby status and several tenants occupy portions of the depot property (ETA 2000).

Remedial and Regulatory History

The Army began environmental investigations at LAAP in 1978 under the Department of Defense's Installation Restoration Program (IRP). Most of the investigations focused on releases from former ammunition lines and lagoons to determine if they posed any threats to public health or the environment. A preliminary assessment/site investigation (PA/SI) of LAAP by the U.S. Army Toxic and Hazardous Materials Agency (USATHAMA) completed in May 1978, confirmed the presence of explosive contamination in the plant loading and disposal area from former site operations (LAAP 2002, EPA 2001).

As a result of the contamination detected at LAAP, on March 31, 1989, the U.S. Environmental Protection Agency (EPA) added LAAP to the National Priorities List (NPL) of sites to be investigated primarily due to groundwater contamination from the Area P pink water lagoons. The NPL is part of EPA's Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as "Superfund." The Army signed a Federal Facility Agreement (FFA) with EPA and the Louisiana Department of Environmental Quality (LDEQ) to outline a comprehensive strategy for conducting environmental investigations and completing remedial actions on LAAP property where hazardous materials may have been disposed, spilled, or stored (EPA 2002).

Environmental investigations to date have helped identify 23 potential areas of concern (AOCs) at LAAP where groundwater, soil, and/or surface water are contaminated or suspected to be contaminated with metals and explosive compounds, such as trinitrotoluene (TNT), dinitrotoluene (DNT), 4-DNT, and tetryl (EPA 2001).

The Army grouped certain AOCs containing significant contamination into four operable units (OUs) based on the type of site, the potential threat to groundwater from source area contamination, and the level of effort required to complete a remedial investigation (RI). Table 1 lists the OUs and other AOCs and describes past investigations and completed or planned remedial investigations. The table also provides an evaluation of potential public health hazards associated with each site. Key AOCs at LAAP are shown in Figure 2.

The OUs consist of:

OU for Soils/Source Area. This OU includes the first seven AOCs identified through the PA/SI in 1978 and remedial investigations and feasibility studies (RI/FS) in 1985. The AOCs are:

  • Area P (16 pink water lagoons),
  • Burning Ground 8 Landfill (BG-8),
  • BG-8 Lagoon,
  • Burning Ground 5 (BG-5),
  • Oily Waste Landfill,
  • M-4 Lagoon, and
  • Landfill 3 (LF-3).

OU for Groundwater. This OU consists of the contaminated shallow groundwater beneath each of the AOCs at LAAP. The groundwater is primarily contaminated with explosive wastes.

OU for Y-Line Etching Facility. Additional site investigations in 1993-1994 indicated that soil at the Y-Line Etching Facility AOC was contaminated with chromium and solvents. RI activities began at this AOC in 1994-1995.

OU Nine Load Lines and Three Test Areas. This OU includes Areas C, D, E, F, G, H, J, K, and S, located primarily on the west side of the installation. Areas C, D, E, F, and S produced large item explosive devices, while Area H, G, J, and K produced mostly small caliber ammunition. These areas were investigated through RI activities, the results of which were presented in a draft in September 2001 (LAAP 2002b).

In response to detecting high levels of contamination at Area P, the Army has completed interim remedial actions that included excavating and incinerating 100,000 tons of explosives-contaminated soil and treating over 50 million gallons of wastewater from the lagoons. The excavated lagoons were backfilled with the treated soil, capped, and revegetated under the Resource Conservation and Recovery Act (RCRA). The Army installed a barbed-wire fence around the Area P lagoon cap and regularly monitors the cap to ensure its integrity. Signs posted around the lagoons read "Area P Decontamination Area" (EPA 2001).

The Army has completed most investigations and prepared records of decisions (RODs) for the Soil OU and the Y-line Etching Facility OU. The RODs establish required remedial actions, if any, for each of the areas under investigation and the groundwater plumes. No remedial actions under CERCLA were deemed necessary at either of these OUs because the Army found that exposure to soils posed no current risks (ETA 2000). If the land-use changes from industrial, or if the Army relinquishes control of or ceases to restrict access to LAAP, this determination will be re-evaluated.

Twelve additional study areas, which include nine load-assemble-pack (LAP) lines (Lines C, D, E, F, G, H, J, K, and S) and three test areas (Test Areas 6 and 7 and the Central Proving Ground), are at different stages of investigations to characterize soil contamination. The Army collected data about soil contamination at these areas through a 1996 soil investigation and a 1999 follow-on RI. The results of these studies will be used by the Army in preparing a risk assessment and identifying ways to limit potential exposure and/or contaminant migration. The report for the follow-on study (2001) contains recommendations for no further action with respect to soil at 9 of these 12 study areas. The three remaining study areas (DA-9, the Victory Road Landfill, and the Detrex Lagoon Northeast) are being followed for groundwater contamination under the groundwater OU.

ATSDR Activities

Through the public health assessment (PHA) process, ATSDR assesses site conditions from a public health perspective to determine whether people can be exposed to site-related contaminants through contact with the groundwater/drinking water, surface water, soil, biota, or air. As part of the PHA process, ATSDR prepared a preliminary PHA for the LAAP site on April 10, 1989. ATSDR's preliminary review found no exposure situations requiring immediate attention, but did indicate that more information was needed to fully evaluate several potential exposure situations at LAAP. ATSDR conducted a site scoping visit on February 25-26, 1991. ATSDR recommended further characterization of environmental media on and off site to better address potential human exposure pathways.

Since 1991, additional data about environmental conditions at LAAP have become available. ATSDR revisited the LAAP site on December 10-11, 2001 to collect additional information necessary to identify public health issues related to environmental contamination at the facility. During the visit, ATSDR staff toured the facility, reviewed installation files, and met with Army and LAAP representatives. ATSDR again did not identify any exposure situations requiring immediate attention. ATSDR did note four exposure pathways that required further evaluation, including the consumption of groundwater/drinking water, contact with soil, contact with surface water/sediment, and consumption of local fish and game. ATSDR's evaluation of these exposure pathways is presented in the Evaluation of Environmental Contamination and Exposure Pathways and in the Community Health Concerns sections of this document.

Demographics and Land Use

ATSDR examines demographic data (i.e., population information) to determine the number of people potentially exposed to environmental chemicals and to determine the presence of sensitive populations, such as children (age 6 and younger), women of childbearing age (age 15-44), and the elderly (age 65 and older). Demographic data also provide details on population mobility which, in turn, helps ATSDR evaluate how long residents might have been exposed to environmental chemicals.

In addition to demographic information, ATSDR examines the many ways that the people near LAAP might use the land and its natural resources. ATSDR does this to determine what activities might put people at risk for exposure. This information is important because land use affects people's exposures to contamination by controlling the types and frequencies of activities in those areas. ATSDR uses this information as part of the evaluation of contamination and exposure in this document. Below, we provide both demographic and land use information used in our analysis.

During peak operation, the number of workers at LAAP exceeded 7,000 persons. Some workers also lived in staff housing located on installation property. Less than 100 workers are currently employed at LAAP, which includes military personnel, contractor personnel, and Army civilian workers. The installation is surrounded by a perimeter fence and access to LAAP was and still is restricted to military personnel and civilian employees. Authorized visitors may enter by passing a security guard station, registering their vehicle, and obtaining a pass. Access to contaminated areas is not limited once within the LAAP boundaries, except for those fenced-off areas.

LAAP is located in northwestern Louisiana in the town of Doyline (population 896). Doyline's business center and residential area are located more than 2/3 miles southeast of Area P, across State highway 164. The community of Goodwill is located about 3/4 miles northeast of Line C, across State Highway 80. Some people might also live in a group of buildings (believed to be residences) located about 1 mile northwest of Test Area 6 (IT Corporation 1999a). As indicated in Figure 3, about 2,467 people live within a 1 mile buffer of the site boundary, within this predominantly agricultural area, including 206 children 6 years of age and younger and 345 adults age 65 and older (ATSDR 2002). The city of Minden (population 14,697) is 2 miles northeast of LAAP. Other nearby cities include Shreveport (population 198,525) and Bossier City (population 52,721), which are located about 22 miles west of the plant.

LAAP contains vast (11,390 acres) woodland, much of which serves as a buffer zone between the industrial operations areas and the surrounding communities. The remaining acreage is divided between production lines and mission support (2,970 aces) and administrative and staff support buildings (74 acres). A portion of the administrative area houses a National Guard Youth Challenge Camp. The Webster Parish Sheriff's Office has also leased a portion of Area B, a non-industrial property formerly used as a maintenance area, for use as a minimum-to-medium security prison (PSI 2000a, 2000b, Williams 2002b).

Permitted hunters using shot guns are also allowed to access the site between 5:30 am to noon and 2 pm to dusk during hunting season (roughly October-January). Up to eight hunters may occupy a 600-acre area at any one time. Recreational activities such as swimming or fishing are not allowed at the creeks/streams that traverse LAAP. Some people may fish at Clarke Bayou or Bayou Dorcheat, that border LAAP, and at Lake Bistineau south of LAAP.

Quality Assurance and Quality Control

In preparing this PHA, ATSDR reviewed and evaluated information provided in the referenced documents. Documents prepared for the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) program must meet standards for quality assurance and quality control measures for chain-of-custody, laboratory procedures, and data reporting. The environmental data presented in this PHA are from Army site and remedial investigations. Based on our evaluation, ATSDR determined that the quality of environmental data available for LAAP is adequate for making public health decisions.


EVALUATION OF ENVIRONMENTAL CONTAMINATION AND EXPOSURE PATHWAYS

Introduction

Defining Exposure

ATSDR's PHAs are exposure (or contact) driven. Given sufficient exposure levels, chemical contaminants disposed of or released into the environment have the potential to cause adverse health effects. However, a release does 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.

Selecting Exposure Situations for Evaluation

ATSDR evaluates 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. ATSDR also identifies an exposure pathway as completed or potential, or eliminates the pathway from further evaluation. Completed exposure pathways exist if all elements of a human exposure are present. (See Appendix B for a description of the elements of a completed exposure pathway.) A potential pathway is one that ATSDR cannot rule out, because one or more of the pathway elements can not be definitely proved or disproved. A pathway is eliminated if one or more of the elements is definitely absent.

If exposure was, is, or could be possible, ATSDR then considers 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 (CVs). CVs are developed by ATSDR from scientific literature available on exposure and health effects. These CVs 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.

CVs are not thresholds for adverse health effects. In order to be conservative and protective of public health, ATSDR CVs are generally based on 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 CVs, ATSDR further analyzes exposure variables (for example, duration and frequency), the toxicology of the contaminant, other epidemiology studies, and the weight of evidence for possible health effects.

Some of the CVs used by ATSDR scientists include ATSDR's environmental media evaluation guides (EMEG), reference dose media evaluation guides (RMEG), and 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 CVs developed by ATSDR for screening environmental contamination for further evaluation.

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.

Determining Health Impacts of Exposures

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 can be 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 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 actually 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.

Exposure Situations at LAAP

ATSDR analyzed data for LAAP's AOCs to determine if they are associated with past, current, or future public health hazards. Table 1 provides a description of each site and a summary of our evaluation. Our review indicated that most sites at LAAP are not associated with any known public health hazards because: (1) contaminant concentrations detected are too low to pose a health hazard, or (2) past or current exposure to the general public has been prevented.

From this review, however, ATSDR did identify four exposure pathways at LAAP for further evaluation. These pathways are:

  • Consumption of contaminated groundwater/drinking water

  • Contact with contaminated surface soil

  • Contact with contaminants in surface water and sediment of local waterways

  • Consumption of locally-caught fish and deer

Our evaluation on exposure pathways is summarized in Table 2 and discussed in greater detail in the following discussion. In response to community concern, ATSDR also addressed potential exposure to explosive compounds and pesticides used at LAAP and breast cancer occurrence in areas near LAAP; low birth weights reported for communities near LAAP; exposure of permitted hunters to contaminants in soil while visiting the site; and exposures associated with the use of portions of the LAAP for a minimum-to-medium security prison.

To acquaint the reader with terminology and methods used in this PHA, Appendix A provides a glossary of environmental and health terms presented in the discussion, and Appendix B outlines the assessment methodology and lists the comparison values used in this PHA. Appendix C contains comments received during the period public comment period for the PHA (January 23 to February 23, 2003) and ATSDR's responses to those comments.

Evaluation of the Groundwater/Drinking Water Pathway

Discussion

Hydrogeology and Groundwater Use

Water beneath LAAP exists in two primary groundwater systems known as the shallow aquifer and the deep aquifer. The shallow aquifer is made up of the inter-connected Upper Terrace Sand and the Lower Terrace Sand/Sparta Sand groundwater systems. Groundwater flow in the Terrace Sand portion of the shallow aquifer is primarily influenced by local surface features and surface water drainage, such as Boone and Caney Creeks. Groundwater in the Sparta Sand appears to follow a northeasterly flow (Woodward-Clyde 1994, ESE 1996). The shallow aquifer is not used as a source of drinking water by LAAP or by neighboring municipal sources. The Sparta Sand unit is regionally an extensive aquifer east and northeast of LAAP. In these areas, the Sparta Sand portion of the shallow aquifer is the primary source of drinking water (PMC 2001a).

The deep aquifer known as the Wilcox-Carrizo Sand aquifer ranges in depth from 130 to 225 feet below ground surface and averages about 475 feet in thickness. The deeper aquifer has been and still is used by LAAP, Doyline, and Goodwill as a source of drinking water. A confining layer known as the Cane River Formation lies between the shallow aquifer and the deeper aquifer. The formation is encountered about 30 to 70 feet below the ground surface beneath the LAAP seven study areas and at the LAAP water supply wells (ESE 1996). Soils and clay in the confining layer are packed so tightly that water cannot easily travel through this layer from the shallow aquifer to the underlying deeper aquifer. Recent RI results, however, indicate that the Cane River Formation pinches out west of Area P near Caney Creek, creating a situation where the shallow Terrace Deposits lie directly on top of the Wilcox unit. If this is the case, contaminants could possibly move from the contaminated shallow aquifer to the deeper aquifer in the portion of the site west of Area P. Despite RI findings, the Army contends that a U.S. Army Corp of Engineer study provides evidence that the shallow (Terrace deposits) and deeper aquifers are not connected in the area in question but are separated by a substantial clay layer associated with the Wilcox formation (EPA 2001).

Nature and Extent of Contamination at LAAP

Environmental investigations since the late 1970s have identified explosive compounds, metals, and volatile organic compounds (VOCs) in the shallow aquifer beneath LAAP. Contaminants have primarily originated from explosive-laden wastewater that was generated from former site operations and disposed of in unlined surface impoundments or lagoons. The contaminants in the lagoons eventually seeped through the soil and into the underlying shallow groundwater. Some of the highest levels of contaminants were detected in groundwater beneath Area P, BG-5, and BG-8. Groundwater contamination at Area P, BG-5, and BG-8 is described in greater detail in the following discussion and summarized in Table 3 of this document.

Area of Concern: Area P

Environmental investigations at LAAP in the early 1980s identified contaminants, primarily explosive compounds and to a lesser extent metals, in groundwater samples collected from the Upper Terrace portion of the shallow aquifer beneath Area P. The highest concentrations of explosive contaminants were found in the Upper Terrace directly beneath the former lagoons, where research and development explosive (RDX, or cyclotrimethylenetrinitriamine) and TNT reached high levels up to 27,000 parts per billion (ppb) and 25,000 ppb, respectively. Explosive contaminants migrating in the Upper and Lower Terraces reached LAAP's southern boundary by 1984 and 1986, respectively, thus marking the first time that contaminants had potentially migrated beyond the site boundary. By 1988, explosive contaminants, mainly levels of RDX (2.6 ppb-63 ppb), had migrated about 2,500 feet from the former lagoons at Area P to off-post monitoring wells south of the lagoons (PMC 2001a). Subsequent sampling by the U.S. Army's Corp of Engineers in October 1988 failed to detect RDX in the same off-post monitoring wells, but found small amounts of 1,3,5-trinitrobenzene (1,3,5-TNB) (1.23 ppb-1.71 ppb) (USATHAMA 1989).

The Army conducted an interim removal action in 1989-1990, removing explosives- contaminated soil from Area P and covering the area with a cap. Following the removal action, sampling indicated that the explosive compounds had not migrated a substantial amount since 1986. Later reports in 1994 also confirmed that the groundwater quality had also improved, and that concentrations of explosive compounds were gradually declining (PMC 2001a).

A 1996 study showed that the contaminants in the Lower Terrace Deposits of the shallow aquifer were now migrating toward the northeast. Army scientists believed that the groundwater flow pattern shifted following the removal of the former pink water lagoons at Area P. Pink water is the waste water produced from explosive manufacturing operations. The water is pink or red as a result of the presence of explosive chemicals, such as RDX, HMX, or TNT. Sixteen pink water lagoons were active in Area P from the 1940s until March 1981. Groundwater flow in other directions appeared to be minimal.

Most recently the Army tested groundwater monitoring wells at and near Area P in 1998 for explosive compounds, VOCs, metals, semi-volatile organic compounds (SVOCs), and pesticides. These results confirmed that explosive compounds were still present beneath Area P (RDX at levels up to 19,800 ppb) in similar concentrations and distribution to previous investigations, but no longer along the site boundary. These data continued to suggest that groundwater flow beneath Area P is still toward the northeast in the Lower Terrace and to the west-southwest in the Upper Terrace. VOCs and SVOCs were not detected in any wells at levels of concern. One sample near the site boundary contained arsenic at 19.4 ppb and above ATSDR's CV for drinking water of 0.02 ppb.

Area of Concern: BG-5

Several rounds of groundwater monitoring between 1979 and 1990 tested the shallow aquifer (specifically the Lower Terrace/Sparta Sand portion) beneath BG-5. Samples were analyzed for explosive compounds, metals, VOCs, and/or pesticides. Results indicated that explosive compounds, such as RDX and TNT, were present most frequently and in the highest concentrations. Other compounds were detected sporadically and generally at levels below ATSDR CVs.

Some of the highest levels of explosive compounds were detected in the deeper portions of the Lower Terrace /Sparta Sand deposits and in wells west and southwest of BG-5. For example, RDX was detected in the shallow groundwater at levels up to 707 ppb in 1986, 760 ppb in 1986, and up to 3,231 ppb in 1990. Groundwater flow from BG-5 moves westward toward and discharges into Boone Creek. Groundwater immediately east of Boone Creek was found to contain RDX levels up to 364 ppb in 1990 sampling. Groundwater wells north and east of the BG-5 site were not found to contain any explosive contaminants, nor were wells on the western side of Boone Creek.

Most recent investigations in 1998 confirmed earlier findings that the highest levels of explosive contaminants exist along the western boundary of BG-5, near Boone Creek. However, no contaminants had migrated beneath and to the western side of Boone Creek, or toward drinking water wells (PMC 2001a).

Area of Concern: BG-8

Groundwater from the shallow aquifer (specifically the Lower Terrace/ Sparta Sand portions) beneath BG-8 was monitored over several sampling events between 1979 and 1995. More than 30 wells make up the monitoring network, including several wells along the southern boundary of LAAP to track possible contaminant movement beyond the site property. Collected samples were tested for the presence of explosive compounds, VOCs, metals, and/or pesticides.

Explosives were again the primary contaminant of concern, with detections throughout the central portion of BG-8. With the exception of arsenic, other compounds were detected sporadically and generally at levels below ATSDR CVs.

By 1986, explosive compounds were believed to be discharging into Boone Creek and moving south beyond the LAAP boundary. By one account, the explosive contaminant, RDX (25.0-31.0 ppb), was reportedly identified in 1987 in two monitoring wells located 300 feet beyond LAAP's southern boundary, directly south of BG-8. The detections were later considered anomalies because no contamination had been identified in wells lying between BG-8 and the perimeter fence line, and RDX was not found during 1988 retests of the two wells (PMC 2001a). The explosive compound, 1,3,5-TNB (0.3 ppb), was detected in one well, but at trace levels (USATHAMA 1989).

Maximum concentrations of explosive contaminants in groundwater have decreased over time to 531 ppb in 1998 at a location downgradient of the sewage treatment plant. Over time, the actual size and orientation of the relatively low levels of BG-8 explosive compounds in groundwater along the southern boundary has also changed from sampling round to sampling round. Sampling in 1991, 1995, and 1998 found explosive compounds in wells along the southern fence line, but not in any off-site wells. Also, some of the contaminants from BG-8 had crossed beneath Boone Creek, though for only a short distance (PMC 2001a).

Potential Public Health Hazards

ATSDR next examined whether anyone who lives/works at or near the LAAP facility has been or could be exposed to the contaminants in groundwater. ATSDR did this by identifying potential points of exposure–that is, drinking water wells–located on the LAAP property or in proximity to the site. ATSDR identified three area drinking water supplies that draw from groundwater sources: the public water supply for Doyline, Goodwill, and the city of Minden; drinking water supply wells at LAAP; and area private wells (see Figure 5). The following discussion evaluates information for these water supplies and possible exposures to site-related contaminants.

Public Water Use: Past, Current, and Future

The Community of Doyline

Most residents of the community of Doyline located along the southern site boundary receive their water from the Doyline community water supply which operates five wells south of LAAP. All Doyline drinking water wells, which were installed in 1985 and placed on-line in 1986, draw water from the deep Wilcox aquifer. The closest Doyline drinking water well (WWELL1) to LAAP is located over 1,000 feet from the site's southern boundary.

Public water supplies are routinely tested for bacterial, chemical, and radiological parameters to ensure that the water meets enforceable drinking water standards considered protective of public health by the U.S. Environmental Protection Agency (EPA). EPA-required routine monitoring does not, however, test for explosive compounds, such as TNT, RDX, and HMX.  As a precautionary measure, the Army samples the public wells near LAAP for explosive compounds. Initial tests of the public wells in 1989 showed low levels far below levels of health concern. No LAAP- related contaminants have been detected during routine follow-up testing.LAAP's contractor (Morthon Thiokol) tested water from wells 1 and 4 (WWELL 1 and WELL 4) of the Doyline community drinking water supply for explosive compounds in 1988 as part of the USATHAMA's RI investigations. Concentrations of explosive compounds, including HMX, RDX, and TNT, were below detection limits. It should be noted, however, that the detection limit of the method used in the analysis for RDX of 4.73 ppb was above ATSDR's CV for RDX of 0.3 ppb.

The Army further sampled the Doyline water supply in July, September, October, November, and December of 1989, and January 1990 after determining through groundwater monitoring that contaminants had migrated with the shallow groundwater beyond the site's southern boundary. The sampling served as a precautionary measure since drinking water wells draw from the deeper "uncontaminated" Wilcox aquifer and are not in the predominant direction of groundwater flow from LAAP. Water samples were collected from the three Doyline public water supply wells (1 [WWELL 1], 2 [WWELL 2], and 3 [WWELL 3]) located closest to the site. The results indicated that contaminants were only detected in the December 1989 sampling event. During that sampling event, high melting explosive (HMX-or cyclotetramethylenetetra-nitriamine) (1.68-3.37 ppb) and tetryl (0.54-0.55 ppb) were detected in the drinking supply wells, but at levels below ATSDR's CVs of 500 ppb and 370 ppb, respectively. RDX was also detected (0.7-3.53 ppb) in December, with levels above ATSDR's CV (CREG) of 0.3 ppb. Through the data validation process, however, the December sampling results were deemed to be of questionable quality. Because the majority of sampling events indicated levels below ATSDR's CVs, exposure, if any, to explosive compounds would have been for a short period of time. Considering this information, exposure, even to the maximum concentration detected in the wells, for the short duration that it may have been present is not likely to result in harmful effects.

The affected wells were immediately resampled and the analytical results were below ATSDR CVs. Subsequent sampling in 1991 and semi-annual sampling in 1993 indicated levels below detection (Woodward-Clyde 1994, ESE 1997). The well field was most recently sampled in 1997 and 2001, at which time no explosive compounds were detected (PMC 2001a). LAAP will continue to monitor groundwater movement from the site boundary and off-site groundwater quality to identify and diminish the threat of potential health hazards. The U.S. Army Corps of Engineers will also continue to sample Doyline's drinking water supply every year or every other year for at least another 10 years, in accordance with CERCLA guidance (Williams 2002).

The Community of Goodwill

Residents of the unincorporated community of Goodwill, located about 3/4 miles northeast of Line C at LAAP, rely on drinking water provided by the Village Water Supply. The Village water supply operates four wells located across State Highway 80, just north of LAAP. The Army tested water from the four wells (8 [WB384], 9 [WB385], 10 [WB374], and 11 [WB407]) in 1989, even though groundwater flow is away from this area and contaminants have not been detected beyond the northern site boundary. With the exception of 1,3,5 trinitrobenzene at 0.81 ppb (well below ATSDR's CV of 300 ppb) in the Village Water Supply Well 8, no other contaminants were detected (Woodward-Clyde 1994). Any exposure to the explosive compound at the detected concentration for the short duration that it may have been present is not likely to pose a health hazard. Follow-up testing of the wells indicated that explosive compounds were below ATSDR CVs. Monthly testing of the wells between July 1989 and January 1990 showed either non-detects or negligible levels of explosive compounds, as did subsequent sampling in 1991 and semi-annual sampling in 1993 (Woodward-Clyde 1994, ESE 1997). The Village Water Supply wells were most recently sampled in 1997 and 2001, at which time no explosive compounds were detected (PMC 2001a). The U.S. Army Corps of Engineers will continue to sample the Village Water Supply along with the Doyline wells into the future (Williams 2002a).

The City of Minden

The city of Minden, about 2 miles northeast of the LAAP's eastern boundary, relies on water from 10 wells that draw from the Sparta Sand portion of the shallow aquifer as their principal source of drinking water. Bayou Dorcheat, located between Minden and LAAP, serves as a boundary to groundwater flow in the Upper Terrace deposits and, to some extent, for groundwater in the Lower Terrace and Sparta Sand Aquifer (ESE 1996, IT 1999b). Groundwater from LAAP flows into the bayou, gets diluted, and, therefore, never reaches the Minden community wells (ESE 1996, Minden 2002).

On-Site Drinking Water: Past, Current, and Future

Although the shallow groundwater beneath LAAP contains high concentrations of explosive compounds, it has never been used for drinking water. Over its years of operation, LAAP has supplied its employees and few residents with drinking water drawn from nine water wells (4A, 6, 12, 14, 18, 19, 20, 21, and 22) that drew water from the deep Wilcox-Carrizo Sand aquifer beneath the facility. Collectively, the nine water wells were capable of drawing up to 2.75 million gallons per day (USAEHA 1990).

The water wells were operated on a rotational basis by co-activating two wells for two to three days until about 2 million gallons of combined water flow had been pumped. (Each well was fitted with automatic chlorination equipment.) Water from operating wells would then enter a closed-loop distribution system that serviced all production, maintenance, administration, and staff housing via two feeder lines. Excess water from the wells was stored in one of five elevated on-site storage tanks. At various times, any one well might have been removed from service for maintenance. For example, well 14 was often inactive due to excessive hydrogen sulfide concentrations. By 1993, most wells had been converted to standby status. Today, two deep wells still actively supply the plant with drinking and production water. Most plant employees, however, prefer to drink bottled water (Williams 2002a).

Sampling has not detected contaminants in the deeper aquifer beneath LAAP.(1) The Cane River Formation (confining layer) present below each of the seven LAAP AOCs and at the LAAP water supply wells restricts groundwater and contaminant flow from the shallow to the deeper aquifer. At various points over time, total dissolved solid (TDS) levels have exceeded EPA's secondary MCL of 500 parts per million (ppm) in the plant's drinking water supply. TDS at levels above the MCL can impart an undesirable taste to the water, but are not expected to pose a health concern. Future exposure to contaminated groundwater is unlikely to occur because LAAP does not anticipate using the contaminated groundwater for drinking or other domestic uses and the plant will continue to provide its employees with bottled water (USAEHA 1990). Considering this information, ATSDR concludes that LAAP employees and residents have not, nor are they likely to, come in contact with contaminated groundwater.

Private Wells: Past, Current, and Future

Many people in the area get their drinking water from private wells. According to EPA, as many as 1,300 private wells may exist in a 3-mile buffer around LAAP boundaries (EPA 1989). ATSDR has limited information on private well use in the area and therefore discusses potential impacts to these wells in the discussion that follows.

Private well use beyond LAAP's southern boundary

Certain Doyline residents south of LAAP reportedly use private wells that draw from the upper- most layer (Upper Terrace Deposit) of the shallow aquifer, but the exact number and location of each well are not known. LAAP detected explosive compound concentrations in boundary wells and off-site monitoring wells during 1984-1989 sampling south of Area P and BG-8. Levels were generally low and far below ATSDR CVs. Off-post contaminant migration to the south (and toward Doyline) had been substantially reduced by 1994.

Within the area of off-site contamination, there may be private wells. Residents who receive their drinking water from private wells are, however, not required to test their well water. No other private well sampling data exists. Without sampling data, ATSDR does not know whether or to what extent LAAP-related contamination has entered these private wells. Tests indicate that contaminants at levels below ATSDR CVs reached areas beyond the LAAP southern site boundary. Unidentified private wells in the area of contamination may have likewise been impacted by explosive compounds, but at similar low levels. Exposures to such low levels of explosive compounds are not expected to be of health concern. LAAP will continue to monitor groundwater movement from the site boundary and off-site groundwater quality to identify and diminish potential threats to private wells close by.

Private well use beyond LAAP's northern, eastern, and western boundaries

Information reviewed by ATSDR suggests that groundwater contaminants are not migrating beyond site boundaries north, west, or east of LAAP that could threaten potential private well use in the area. Additionally, no private wells have been identified within the community of Goodwill, located just beyond the northern boundary of LAAP.

Measures to Reduce Potential Future Exposures

Several measures are in place to ensure that the groundwater contamination currently at the plant will not affect local water supplies in the future. These measures include:

  • Ongoing groundwater monitoring. LAAP will continue to monitor the groundwater to track possible off-site contaminant migration at LAAP. LAAP is studying site conditions to determine whether natural attenuation is effectively reducing the existing levels of environmental contamination.

  • Routine testing of public water supplies. The Safe Drinking Water Act requires every public water supply system to test drinking water routinely for contamination. Compliance with the Safe Drinking Water Act will help ensure that authorities detect and promptly address environmental contamination that may enter drinking water supplies, thus reducing any exposures that might occur in the future. The Army has regularly tested the Doyline and Village Water Supplies for explosive compounds, which are not part of the Safe Drinking Water Act's required parameters.

  • Land use restriction. Industrial portions of LAAP will most likely remain zoned for industrial use. As such, groundwater will not be used as drinking water supplies for the public.

Collectively, these measures will help ensure that contamination does not reach drinking water supplies, thus preventing health hazards from happening in the future.

Evaluation of the Surface Soil Pathway

Discussion

Nature and Extent of Contamination

The Army has investigated soil at 20 of the 23 AOCs. Their investigations have revealed that soil at some of these areas is contaminated with explosive compounds, primarily TNT, HMX, and RDX. Associated by-products of TNT are also concentrated in the soil at LAAP. Data collected through these investigations indicated that the contaminated soil tended to be found near processing buildings that handled large amounts of explosive compounds or other chemicals. Contamination was not found near other buildings, such as administrative or process-support buildings, also located in the production area. Results of soil sampling are described below by OU/study areas and summarized in Table 1 of this document.

Soils associated with the OU for the Soils/Source Area

This OU includes Area P, BG-8 Landfill, BG-8 Lagoon, BG-5, Oily Waste Landfill, M-4 Lagoon, and LF-3. Numerous investigations have been performed on these areas to determine if specific chemicals remain in soil after past operations. Soil samples were collected from areas most likely to contain the highest concentrations of explosive compounds and VOCs. Results indicated that RDX was present at the highest concentrations at the Area P (above 100 ppm), BG-8 Landfill/Lagoon (up to 48.32 ppm) and the BG-5 Landfill former burning ground (up to 100 ppm). Other explosive compounds of concern detected at these AOCs include 1,3-dinitrobenzene, 1,3,5-trinitrobenzene, and/or 2,4,6 trinitrotoluene (ESE 1996). These compounds represent the most mobile, toxic, and frequently detected chemicals in surface soil at LAAP. Explosive chemicals were not found in surface soil samples collected from the M-4 Lagoon.

The Army completed interim remedial actions at Area P in 1987-1990 that excavated and incinerated 100,000 tons of explosives-contaminated soil and treated over 50 million gallons of wastewater from the lagoons. Sampling of the excavated area confirmed that the soil with HMX and RDX above 100 ppm had been removed. The excavated lagoons were backfilled with the treated soil, capped, and revegetated under RCRA. The Army installed a barbed-wire fence around the Area P lagoon cap and regularly monitors the cap to ensure its integrity. Signs posted around the lagoons read "Area P Decontamination Area" (ESE 1996).

LAAP will remain industrial and will not be used for residential or agricultural uses in the future. Existing Army regulations make the sale of the LAAP property unlikely. Furthermore, Superfund guidance requires that if the property is sold or transferred, each deed must contain language specifying actions necessary to protect public health and the environment that will be completed before the date of property transfer (ESE 1996). Given these conditions, a ROD signed in March 1997 recommended no further action for soil at the AOCs (ETA 2000).

Soils associated with the OU for the Y-Line Etching Facility

Site investigations in 1993-1996 indicated that soil at the Y-Line Etching Facility AOC was contaminated, primarily with chromium and solvents, possibly the result of chromic acid spills near the northwest corner of Building 2600. Chromic acid probably leaked or spilled from the etch bath, contaminating surrounding soil. Limited amounts of metals in the soil may have also been the result of wind dispersion of metals emitted from the high velocity fans on top of Building 2600. Results of the RI at the Y-line indicated that chromium concentrations in samples ranged from 11.5 to 1,800 ppm. Excluding the chromium concentration of 1,800 ppm, the mean concentration in the samples was 29.6 ppm and just slightly above the mean background concentration of 22.3 ppm. Soil concentrations of other heavy metals were not significantly above background concentrations (ETA 2000).

Previous investigations of the Etch Facility by the U.S. Army Environmental Hygiene Agency (USAEHA) in 1991 found chromium in surface soil at levels between 11.5 and 5,300 ppm, with a mean concentration of 236 ppm. The highest concentrations were detected in soil near the chromic acid bath. The difference between the concentrations reported by the USAEHA investigation and the RI may be due to different sampling strategies. The USAEHA selectively sampled hot spots, while the RI performed grid point sampling to evaluate possible wind dispersion of metals at the site (ETA 2000). It should also be noted that metals were not found at levels above background in the subsurface layers, indicating that the subsurface soil at the site may not be a key source of metals in groundwater. Contaminated soil at the Y-line is not expected to become airborne (as a result of wind erosion) largely because the site is paved or highly vegetated (ETA 2000).

As stated above, LAAP will remain industrial and will not be developed for residential or agricultural uses in the future. Existing Army regulations make the sale of the LAAP property unlikely. Furthermore, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Section 120 requires that if the property is sold or transferred, each deed must contain language stating specific actions necessary to protect public health and the environment have been taken before the date of property transfer (ETA 2000). Given these conditions, a ROD signed in February 2000 recommended no further action at the Y-Line.

Soils at other AOCs

In addition to soil at the seven AOCs and the Y Line, 12 remaining AOCs (including load, assembly, and pack [LAP] lines, test areas, and others) required additional investigations. Soil at the remaining AOCs was sampled as part of a 1996 investigation and/or the 1999 follow-on RI. Surface soil samples were analyzed for explosive compounds, VOCs, SVOCs, and metals (PMC 2001a).(2)

Most impacts to soil were primarily from explosive compounds. Concentrated areas of explosive contamination above ATSDR CVs were confined to small areas near buildings that handled or managed materials. Explosive compounds were generally found in the highest concentrations and frequency at Line C. Arsenic was also determined to be in soil at the various AOCs at levels above CVs. There is no known process-related source of arsenic. Rather, arsenic is suspected to be residual contamination from former approved pesticide applications (PMC 2001a). The explosive compounds at most of the LAP lines and test areas, however, do not appear to be significant enough in terms of concentrations or frequency to adversely affect groundwater or surface water at LAAP (PMC 2001a).

Potential Public Health Hazards

Contaminated surface soils at LAAP were inaccessible to the general public because a perimeter fence with gated entrances limited unauthorized access to LAAP. ATSDR looked at whether anyone with access to the site could be exposed to the contaminants in surface soil, either now or in the past. ATSDR determined that people falling into this category include: site workers, hunters, and youth attending the National Guard Youth Challenge Camp. ATSDR also assessed possible exposure of family members of staff who also lived on the grounds of the plant in the past.

ATSDR's review of the data indicated that people allowed on LAAP property were and are not likely to come into contact with harmful levels of soil contaminants for several reasons, including:

  • Explosive compounds were detected at various AOCs located at LAAP. Most AOCs are, however, not associated with any known public health hazard because 1) contaminant concentrations detected are too low to pose a health hazard or 2) the operational area was surrounded by perimeter fencing and/or covered surfaces (e.g., vegetative growth, paved areas). Furthermore, interim remedial actions at Area P have successfully removed contaminated soil. Table 1 provides a summary of potential public health hazards associated with soil contamination at each AOC.

  • Any exposure of workers, residents, hunters, or youth campers to contaminated soil would have been intermittent and brief. Such minimal, infrequent exposure to on-site contaminants, if it had occurred at all, would not be expected to result in adverse health impacts. ATSDR bases it's conclusion on the following:
  • Workers: Workers at any time over LAAP's operational history were not expected to contact contaminated soil for extended periods during their routine responsibilities. Moreover, workers entering these areas must wear protective clothing, which would have further reduced exposure and any associated health effects.

    Residents: At one time, a small number of staff lived on the grounds of LAAP with their families. The living quarters were located outside the industrial area of LAAP so residents would not have had access to contaminated areas.

    Hunters: Permitted hunting, which occurs only a few months a year (roughly October-January), is reportedly limited to LAAP personnel or retirees. While hunting, these individuals are required to stay in a designated area located away from the AOCs. These restrictions greatly limit the number of potentially exposed persons as well as the extent to which any one hunter could actually come in contact with contaminated soil. Unauthorized hunters have attempted to hunt along the boundary of the LAAP but are usually evicted by security that patrols the fence by car.

    National Guard Youth Campers: Campers attending the National Guard Camp are not likely to contact contaminated soil. The camp is located in an administrative portion of the plant which the Army never used to store, process, or dispose of hazardous materials.

ATSDR does not anticipate any harmful exposures to soil contamination in the future. With oversight by EPA and LDEQ, the Army has removed contaminated soil from Area P and determined no further actions are needed for site soil with the understanding that the area will not be used in a way that could endanger human health and the environment. As outlined in the RODs for soil, the industrial portions of LAAP will remain industrial and will not be used for residential or agricultural uses in the future. The Army will retain control of LAAP and restrict access to the property in the future. LAAP is completely fenced in and there are also fences around certain parts of the production areas. Existing Army regulations make the sale of the LAAP industrial property unlikely. Furthermore, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Section 120, requires that if the property is sold or transferred, each deed must contain language ensuring that specific actions necessary to protect public health and the environment will be taken before the date of property transfer. The Webster Parish Sheriff's Office leases a portion of Area B for use as a minimum-to-medium security prison. Please see the Community Health Concern section for a more detailed discussion of this land use arrangement.

In evaluating available monitoring data and proposed remedial actions, ATSDR has identified no current or future public health hazards associated with contaminated soil. ATSDR concludes that contaminants in surface soil pose no apparent current or future public health hazard.

Evaluation of the Surface Water and Sediment Pathway

Discussion

Surface Hydrology and Use

Surface water at LAAP is associated with one of five main water bodies that originate north of the site. Two of the water bodies, Bayou Dorcheat and Clarke Bayou, form much of the eastern and western boundaries of the installation, respectively. The perennial flowing Boone Creek and Caney Branch are the primary streams within LAAP. Boone Creek is located about 3 miles inside LAAP's eastern boundary and drains much of LAAP. Boone Creek was modified during the construction of LAAP to encourage drainage from facility operations. Caney Branch flows 1-2 miles within LAAP's western boundary and discharges to Clarke Bayou. Clarke Bayou, which forms most of LAAP's western boundary, eventually drains into Lake Bistineau 15 miles south of the installation. Clarke Bayou and Bayou Dorcheat serve as effective barriers to groundwater flow in the Upper Deposits of the shallow aquifer and, to some extent, also for the Lower Terrace/Sparta Sand Aquifer, to off-site areas.

The Unnamed Ditch is a modified tributary of Caney Branch developed to drain processing areas located east of Caney Branch. This intermittent flowing stream originates north of Line C and flows south, joining a westerly flowing ditch before intersecting Caney Branch (PMC 2001b). Several smaller intermittent tributaries are located throughout the installation, but each flows into one of the larger streams.

Many of the processing areas drained or released wastewater into the on-site water bodies. Permitted wastewater discharges under the National Pollution Discharge Elimination System (NPDES) were released to Boone Creek from Y-Line, Landfill DA-9, Line S, and the sewage treatment plant at BG-8. Surface water/groundwater from BG-5, oily waste landfarm (OWL), LF-3, BG-8 Landfill, and BG-8 Lagoon were also drained into Boone Creek when the site was operational. Caney Branch received permitted discharges from Area P (via a ditch), M-4, Lines C and D (via the Unnamed Ditch), and Lines G, H, J, and K. Although the site is no longer active, surface water bodies may still receive contaminant discharges from the shallow aquifer or with surface water runoff.

Nature and Extent of Contamination

Between 1979 and 1993, surface water and sediment samples were collected to characterize environmental conditions of Boone Creek, Caney Branch, and the Unnamed Ditch. The Army selected these water bodies for sampling because any surface water releases at LAAP would have eventually flowed toward and into these waterways. Samples were analyzed for explosive compounds; select samples were also analyzed for metals or chlorinated organic compounds. The results of the sampling are discussed below. Bayou Dorcheat and Clarke Bayou, located along the western and eastern boundaries of LAAP, are far from industrial areas and areas of known contamination at LAAP and, therefore, unlikely receptors of surface water runoff or contaminated groundwater (PMC 2001b). For this reason, neither Bayou Dorcheat or Clarke Bayous were monitored for surface water or sediment quality.

Caney Branch

During the plant's operation history, Caney Branch received permitted discharges of waste water under an NPDES permit from Area M-4 via a tributary. The stream also received discharges from Area P via a ditch and Lines C and D via the Unnamed Ditch, and from Lines G, H, J, and K. Samples were collected from Caney Branch between 1981 and 1990. RDX (12.3 ppb), HMX (2.4 ppb), and 1,3,5-TNB (2.2 ppb) were detected in Caney Branch surface water during the 1990 sampling event, primarily near Area M-4. With the exception of RDX, explosive concentrations were well below ATSDR CVs for drinking water. Sediment collected during the 1981 sampling also contained the explosive compound 2,4-DNT (0.03 ppb), but at levels below ATSDR's CV for soil. These past investigations also demonstrated that there is limited groundwater contamination entering Caney Branch.

As would be expected, historical sampling data for Caney Branch may reflect conditions during the operating period, when the stream was impacted from legally permitted discharges. Contamination detected since the permit has expired (and operations have ceased) may reflect contributions from groundwater discharges, if any, or from surface water runoff.

Boone Creek

Several AOCs are located along Boone Creek. These areas include T-7, CPG, BG-5, and BG-8 Landfill/Lagoon. It is expected that surface water and perhaps groundwater from these areas drained into Boone Creek when the site was operational. Sampling between 1984 and 1993 identified explosive compounds and chlorinated organic compounds in surface water of Boone Creek, with increasing concentrations with proximity to and immediately downstream of BG-5 and the BG-8 areas. For example, a sample immediately downstream of BG-5 contained some of the highest detected concentrations of explosives, with a maximum detection of RDX at 16.5 ppb and 2,4-DNT at 3.2 ppb. The concentration for RDX exceeds ATSDR's CV (CREG) for RDX in drinking water. (Higher concentrations of RDX, up to 76.7 ppb, were observed in a sample collected from a surface drainage that drained directly from BG-5 into Boone Creek.) Explosive compounds were detected sporadically and at low concentrations in sediment samples collected in 1981 and 1993 (ESE 1992).

During the plant's operation history, Boone Creek received permitted discharges of waste water under an NPDES permit from Y Line, Landfill DA-9, LAP Line S, and the sewage treatment plant at BG-8. The permit has since expired. As for other on-site streams, historical sampling data for Boone Creek may reflect conditions during the operating periods, showing impacts from legally permitted discharges. Contamination detected since the permit has expired (and operations have ceased) may reflect contributions from groundwater discharges or from surface water runoff.

Unnamed Ditch

Explosive compounds were detected in surface water samples collected from the ditch in 1981, 1988, and 1990 at locations south of Line D and near Area P. Process-related chemicals such as chromium, lead, and nitrate were detected in sediment south of Line D in 1981; explosives were not detected in any sample.

Additional field work proposed for fall 2001/spring 2002 will collect surface water and sediment data to supplement the RI for the Site-Wide Groundwater Operable Unit. Specifically, the data will be used to determine whether source areas and groundwater are contributing explosive compounds and/or other contaminants to the surface water and/or sediment of Boone Creek or Caney Branch.

Potential Public Health Hazards

Explosive compounds have been detected in surface water and sediment of waterways that traverse LAAP. People are not, however, expected to come in contact with harmful levels of contaminants. Fencing bordering the LAAP site restricts the public's access to the on-site portions of the streams and ditch. Some low level contamination may be exiting the site in these streams. There are no indications that people use or will use the water in ways that would result in appreciable skin contact with contaminated surface water or sediment. Any skin contact with explosive compounds in sediment and surface water is therefore expected to be limited in frequency and duration, and not at levels of health concern. ATSDR concludes that incidental exposure to primarily low levels of contaminants in sediment and surface water of Caney Branch, Boone Creek, and the unnamed ditch is not expected to pose a public health hazard.

Evaluation of the Biota Consumption Pathway

Contaminants released from LAAP may accumulate in plants and animals, which are collectively known as biota. LAAP is home to a broad range of wildlife, including several species of fish inhabiting the bayous as well as deer and small game. Many of these plants and animals are important sources of food, but people who consume them may potentially be exposed to contaminants. ATSDR assesses potential environmental impacts on the local fish and resident deer population and any associated health hazards in the discussion that follows.

Consumption of Fish

ATSDR's review of site data suggest that consumption of fish from surface water at LAAP is not a plausible pathway for exposure to site-related contaminants. The water bodies on site are generally small and shallow and not capable of supporting a sustainable fish population (IT Corporation 1999a). Furthermore, access to LAAP is restricted and the public is not permitted to fish in any of the streams or ditches on site.

Fishing occurs at select locations along Bayou Dorcheat and Clarke Bayou that form much of the eastern and western boundaries of the installation, respectively. Fish species caught from these waters include largemouth bass, smallmouth bass, and sunfish. Some of the processing areas at LAAP drained or released wastewater into on-site waterways that ultimately discharge into Bayou Dorcheat and Clarke Bayou. Fish sampling data are not available to indicate whether fish have accumulated levels of contaminants from LAAP. Based on a review of surface water conditions at LAAP, only low levels of contamination, if any, should eventually reach either of these bayous.

ATSDR reviewed available information on the chemical and physical properties of site-related explosive compounds to gain a better understanding of possible effects of explosives in surface water on the local fish population. Available information suggests that explosive compounds, such as RDX, 2,4,6-TNT, and 2,4-DNT that were detected in Caney Branch or Boone Creek, are not known to remain in surface water for a long time or to accumulate to high levels (that is 1,000 times the surface water concentration) in fish that people eat. No data are available on typical levels of HMX in fish, but based on data for RDX, 2,4,6-TNT, and 2,4-DNT, bioaccumulation of HMX in fish is equally unlikely (ATSDR 1995a, b; ATSDR 1997, 1998).

The LDEQ tests fish from Louisiana water bodies to determine whether unhealthy levels of contaminants are accumulating in edible fish populations. The LDEQ primarily tests fish for evidence of mercury contamination. Information through this program is available for Lake Bistineau, into which Clarke Bayou and Bayou Dorcheat empty about 15 miles south of LAAP. Mercury levels in Lake Bistineau fish are within an acceptable range indicating that the fish are safe to eat. Mercury is the most common contaminant in freshwater fish nationwide (LDEQ 2002). While mercury is not a contaminant of concern at LAAP, this information provides some insight into the general quality of the local fish population.

Consumption of Venison

Although LAAP land is inhabited by a substantial deer population which attracts permitted deer hunters during hunting season, privileges are limited to LAAP employees and retirees (IT Corporation 1999a). The permitted hunters using shot guns are allowed to access to the site between 5:30 am to noon and 2 pm to dusk during the hunting season from October to January. Up to eight hunters may occupy a 600-acre area at any one time. Exposure is therefore limited to a small group of people over a short specified time period each year.

Data are not available to indicate whether deer at LAAP have accumulated harmful levels of explosive compounds. Available information suggest, however, that explosive compounds typically are not found in deer meat, nor in other wildlife. Studies conducted at the Alabama Army Ammunition Plant in Childersburg, Alabama, and Joliet Army Ammunition Plant in Joliet, Illinois, analyzed deer tissue for residue levels of explosive compounds, including TNT, HMX, RDX, 2,4-DNT, and/or 2,6-DNT. (U.S.AEHA 1994; Shugart et al. 1991). No detectable levels of explosive compounds were found in either test even though high levels of contaminants may have been present in soil, surface water, or waste water. A human health risk assessment at the Joliet Plant concluded no significant explosive-related risks were associated with eating the deer meat (IT Corporation 1999a). Considering this information, ATSDR does not expect consumption of venison from the LAAP site to cause ill effects for hunters or other consumers.


COMMUNITY HEALTH CONCERNS

LAAP has a community relations plan (CRP) that provides guidance for involving the community and other interested parties in the remediation decision-making process and for distributing information to these parties. As part of its community relations activities, LAAP formed a technical review committee (TRC). The TRC, which is represented largely by local community members, meets periodically to review site documents and comment on actions and proposed actions taken by LAAP. Through the PHA process, ATSDR has gathered information about health concerns identified in the CRP or voiced by community members at TRC meetings. The following is a summary of the community health concerns that have come to ATSDR's attention.

  • Concern about the occurrence of breast cancer and exposure to explosive compounds and pesticides used at LAAP.

It is not likely that breast cancer occurrence can be attributed to environmental releases at LAAP. In a review of the data and possible exposure scenarios, ATSDR did not identify any exposure situations that pose a public health threat or detected levels of chemicals that could be plausibly linked with cancer in the community.

Overall cancer rates for all types of cancer in Louisiana are high. Cancer mortality in Louisiana (215 per 100,000 people) is occurring more often than expected when compared to the nationwide rate (201.6 in 100,000 people), placing Louisiana as the second leading state in the nation for deaths from cancer. The cancer death rate in Webster Parish (284 in 100,000 people) is even higher (American Cancer Society 2001, LDHH 1999). However, cancer occurrence in Webster Parish may not be explained simply by random variation over time. It is important to recognize that cancer is a very common disease, much more common than many people realize. The occurrence of cancer may vary by race/ethnicity, gender, cancer type, geographic distribution, study population, and a variety of other factors. Scientific studies have identified a number of factors that may influence an individual's risk of developing specific types of cancer. Some of these factors include genetics, diet, age (cancer risk increases with age), family history, viruses, exposure to certain chemicals or substances (e.g., benzene, asbestos, vinyl chloride, arsenic, aflatoxin), radiation (ionizing radiation and ultraviolet radiation), alcohol, and tobacco smoke.

Citizens with concerns about breast cancer rates in the communities surrounding LAAP should contact the Louisiana Department of Health and Hospitals at 504-568-5337 or statsweb@dhh.state.la.us.

  • Concern about a perceived increase of low birth weight babies in communities near LAAP.

Low birth weight babies are those who weigh less than 5 pounds, 8 ounces at birth and are often born prematurely (at 37 weeks or less compared to a full term pregnancy of 38-42 weeks). Statistics compiled by the Louisiana Department of Health and Hospital's Office of Public Health for 1996-2000 suggests that the percent of low birth weight in Louisiana (10.18%) is among the highest in the nation (LDHH 2002; CDC 2000). The percent of low birth weights among babies born in Webster Parish from 1996-2000 is 11.7%, and slightly higher than the statewide value (LDHH 2002). It is difficult to interpret the meaning of the Webster Parish value because the percent of low birth weights has not steadily increased from 1996 to 2000, but rather fluctuated year-to-year. For example, the percent of low birth weight babies in Webster Parish rose from 10.1% in 1996 to 13% in 1997, before dropping to 9.8% in 1998.

Many factors may influence risks that lead to low birth weights. Most health professionals agree that the likely causes of low birth weights can be tied to maternal health/behavioral factors, such as inadequate weight gain and smoking history. The increase in multiple births over the past couple of decades has also greatly contributed to the growing number of low birth weight babies. Additional contributing factors included the quality of healthcare during the mothers pregnancy. Some medical researchers suspect that environmental factors may influence the health of an unborn child. None of the explosive compounds at levels detected at or beyond LAAP site boundaries, however, have been linked to low birth weight outcomes.

  • Concern about permitted hunters coming in contact with contaminated soil while visiting the site.

Soil in some areas of LAAP contains explosive compounds and metals left over from former site operations. High levels of contaminants concentrated in certain areas exceed appropriate health-based comparison values established for soil. Frequent contact with soil or eating or breathing in the soil particles in these areas could possibly harm people, including hunters. Hunters who gain permitted access will most likely avoid the areas with the most contaminated soil during their time on site because site access is controlled and contact with soil is restricted due to fencing and vegetation. Any unlikely contact with exposed contaminated soil would be infrequent, of short duration, and not of health concern.

  • Concern about people at the new prison coming in contact with site-related contaminants in the future.

The Webster Parish Sheriff's Office, the primary law enforcement agency for Webster Parish, completed a new minimum security prison facility on about 3.5 acres in Area B of LAAP in the fall of 2001. (The Louisiana Army National Guard occupies a majority of Area B.) Specifically, the Sheriff's Office uses four buildings located in Area B that were last used by LAAP in 1996.

  • Building 1455, a former inert materials warehouse used for storage of various equipment parts, tools, maintenance supplies, and administrative functions, is now used for prison offices, a one-level dormitory, and a 1,200-meal per-day cafeteria/kitchen.

  • Building 1452, a former shop for construction of wood pallets and shipping crates, is used by the prison for storage and a motor pool.

  • Building 1450, a former carpentry shop, is used for an inmate crafts shop.

  • Building 1464, a former laundry, is retained as the prison's laundry (which will not be equipped for dry cleaning).

ATSDR reviewed available site information to determine whether contaminants from former site operations at these buildings exist in environmental media, such as groundwater, soil, or air, at levels that could pose harm to the occupants of the property. Our review of data gathered through Phase I and II environmental site investigations indicated that a 1999 soil gas survey (performed prior to the construction of the prison in 1999) showed two areas of shallow groundwater contamination within the prison boundaries. These areas were: (1): groundwater contamination located about 200 feet northwest, and upgradient, of Building 1455 and (2) groundwater contamination surrounding portions of Buildings 1450 and 1464. The areas of groundwater contamination and any likelihood of human exposure are discussed below.

Building 1455: Contaminants associated with the plume near Building 1455, primarily petroleum hydrocarbons, are believed to be coming from two buildings northwest of the prison area; a former petroleum storage building, Building 1469, and a former gas station, Building 1424 (PSI 2000a). Further investigations indicated that groundwater, at least along the prison boundary closest to the area of contamination, has been affected by petroleum hydrocarbons. One sample of groundwater collected northwest of the prison lease line showed the presence of 1,1-dichloroethane (1,1-DCA) at 139 ppb and cis-1,2-dichloroethene (cis-1,2-DCE) at 13.8 ppb. No other contaminants were detected in groundwater.

Even though the shallow groundwater underlying the prison property is not used for drinking water, ATSDR compared the detected levels of contaminants to our health-based comparison values for drinking water. This comparison suggested that the detected levels of 1,1-DCA and cis-1,2-DCE are not likely to cause adverse health effects even if people were to drink water containing the contaminants at those levels.

Certain volatile organic compounds, such as 1,1-DCA, are able to evaporate from subsurface areas and release to the ambient air. Due to the possibility of this type of contaminant movement, a soil boring was collected from the same location as was the groundwater sample and screened against the Louisiana Department of Environmental Quality (LDEQ's) Risk Evaluation/Corrective Action Program standards (RECAP). These screening standards are considered protective of public health and account for exposure pathways relating to ingestion and dermal contact, as well as inhalation of the emissions of volatile compounds from soil to ambient air. The soil boring contained 1,1-DCA at 0.0184 parts per million (ppm), which is far below LDEQ's RECAP standard for commercial/industrial setting of 470 ppm, thus suggesting that corrective actions to protect public health from exposures to VOCs in soil–or released from soil to ambient air–would not be required. (Note that commercial/industrial standards were deemed appropriate for this screening evaluation since the population in the minimum security prison would reside there for only a short period of time.)

Buildings 1450 and 1464: The second area of groundwater contamination surrounds portions of Buildings 1450 and 1464, and was initially believed to originate from beneath the buildings. Sampling in the area of the second plume failed to identify unacceptable levels of contaminants (contaminants were below laboratory reporting limits) in either groundwater or subsurface soil beneath either of the buildings. The sampling also confirmed that the contaminant source was not within or beneath the buildings. As a result, no further assessment of the property around these buildings was deemed necessary (PSI 2000b). In light of these findings, and given that the shallow groundwater is not used as a source of drinking water, ATSDR finds that the barely detectable quantities of contaminants in the groundwater beneath Buildings 1450 and 1464 are not likely to harm people occupying either building.

ATSDR does not expect that harmful levels of site-related contaminants exist in exposed surface soil around the buildings or that unauthorized persons could gain access to the area. The portion of Area B occupied by the prison was never used for storage nor production of chemicals or munitions. Furthermore, each building is isolated from other portions of Area B and is enclosed within a 12-foot-high chain link fence topped with razor wire (PSI 2000a, PSI 2000b).


ATSDR CHILD HEALTH CONSIDERATIONS

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and children demand special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at greater risk than adults from certain kinds of exposures to hazardous substances emitted from waste sites and emergency events. In general, children are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. They are shorter than adults, which means they breathe dust, soil, and heavy vapors close to the ground. Children are also smaller, so they receive higher doses of chemical exposure proportional to their body weight. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care.

ATSDR has attempted to identify populations of children in the vicinity of LAAP. Approximately 200 children age 6 years and under live within a 1 mile buffer surrounding LAAP, most within the community of Doyline. More than 700 school age children live in Doyline and attend either the elementary school (328 students, pre-kindergarten to grade 5) or the combined middle school-high school (385-400 students, grades 6 to 12) (Doyline 2002). Some children also lived at the LAAP facility in the past.

Like other people living or working at or in the vicinity of LAAP, children may inadvertently come in contact with low levels of explosive compounds. Following a careful evaluation of these pathways as they relate to children, ATSDR determined that harmful exposures unique to children are not expected to occur, because children cannot access the site or locations of contamination at LAAP and no harmful exposures associated with the site are specific to children in the vicinity of the site. Potential exposure pathways are discussed in the Evaluation of Environmental Contamination and Exposure Pathways and Community Health Concerns sections of this PHA.


1 Thiokol Corporation personnel sampled LAAP supply wells for explosive compounds five times between July 1989 and January 1990. Explosive compounds were detected only during the December 1989 sampling event. Data validation of the December 1989 sampling event indicated that the results were at best questionable. No explosive compounds have been detected in any other sampling of the plant's water supply (ESE 1992).
2 Surface soil for this investigation was referred to as the top 0-3 feet below ground surface.


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