PUBLIC HEALTH ASSESSMENT
LONE STAR ARMY AMMUNITION PLANT
TEXARKANA, BOWIE COUNTY, TEXAS
Exposure to or contact with chemical contaminants drive the ATSDR public health assessmentprocess. The release or disposal of chemical contaminants into the environment does not alwaysresult in exposure or contact and chemicals only have the potential to cause adverse health effects ifpeople actually come into contact with them. People may be exposed to chemicals by breathing,eating, or drinking a substance containing the contaminant or by skin (dermal) contact with asubstance containing the contaminant.
When people are exposed to chemicals, the exposure does not always result in adverse health effects. The type and severity of health effects that may occur in an individual from contact withcontaminants depend on the toxicologic properties of the contaminants; how much of thecontaminant to which the individual is exposed; how often and/or how long exposure is allowed tooccur; the manner in which the contaminant enters or contacts the body (breathing, eating, drinking,or skin/eye contact); and the number of contaminants to which an individual is exposed(combinations of contaminants). Once exposure occurs, characteristics such as age, sex, nutritionalstatus, genetics, life style, and health status of the exposed individual influence how the individualabsorbs, distributes, metabolizes, and excretes the contaminant. These factors and characteristicsinfluence whether exposure to a contaminant could or would result in adverse health effects.
To assess the potential health risks associated with contaminants at this site we comparedcontaminant concentrations to health assessment comparison (HAC) values. HAC values are mediaspecific contaminant concentrations that are used to screen contaminants for further evaluation. Non-cancer HAC values are called environmental media evaluation guides (EMEGs) or referencedose media evaluation guides (RMEGS) and are respectively based on ATSDR's minimal risklevels (MRLs) or EPA's references doses (RfDs). MRLs and RfDs are estimates of a daily humanexposure to a contaminant that is unlikely to cause adverse non-cancer health effects. Cancer riskevaluation guides (CREGs) are based on EPA's chemical specific cancer slope factors. CREGsestimate an excess lifetime cancer risk of one-in-one-million for an exposed population. We usedstandard assumptions to calculate appropriate HAC values . Exceeding a HAC value does notimply that a contaminant represents a public health threat, but suggests that the contaminantwarrants further consideration. In some instances, we compared contaminant concentrations inwater to EPA's maximum contaminant levels (MCLs), EPA's lifetime health advisory levels(LTHA), or EPA secondary drinking water standards. MCLs are chemical specific maximumconcentrations allowed in water delivered to the users of a public water system; they are consideredprotective of public health over a lifetime (70 years) of exposure at an ingestion rate of two liters perday. MCLs may be based on available technology and economic feasibility. Although MCLs onlyapply to public water supply systems, we often use them to help assess the potential public healthimplications of contaminants found in water from other sources. LTHAs represent contaminantconcentrations that EPA considers to be protective of noncarcinogenic health effects during alifetime (70 years) of exposure. Secondary drinking water standards control contaminants thataffect the aesthetic qualities of water.
In preparing this Public Health Assessment, ATSDR/TDH relied on the information provided in thereferenced documents. The Agency assumed that adequate quality assurance and quality controlmeasures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analyses and the conclusions drawn in this document are determined by theavailability and reliability of the referenced information.
The majority of the environmental sampling data discussed in this document were collected for theUnited States Department of the Army by their contractor AGEISS Environmental, Inc during thePhase IV Remedial Investigation of the ODA. Data collection and analysis were conducted underthe regulatory oversight of, and in cooperation with, EPA and the TNRCC. These data werecollected between November 1995 through August 1996 . The EPA has approved qualityassurance and quality control (QA/QC) criteria contained in the referenced site investigationdocuments. The EPA also has overseen all aspects of the remedial investigation to ensure that allQA/QC standards were met.
Table 1 lists the types of compounds tested for in the ODA. Table 2 lists the maximum detected concentration of each contaminant found in each of the media sampled. Contaminants reported below their respective detection limits are not listed in the table. ATSDR comparison values for each of the contaminants also are listed in the table. When ATSDR comparison values are not available, EPA's screening values or other comparison values are referenced. Inclusion of a contaminant in the table or the fact that a contaminant exceeds a comparison value does not imply that a contaminant represents a threat to public health.
| Surface |
| Source |
|Volatile Organics |
| || |
|Contaminated Media||Potential Contaminants of Concern||Maximum Detected Concentration||ATSDR Comparison Value*|
|6,240 mg/kg |
|700 - 100,000 mg/kg Background |
4000 mg/kg RMEGchild1
300 mg/kg RMEGchild
1,000 mg/kg RMEGchild
200 mg/kg intEMEGchild2
20,000 mg/kg RMEGchild
20 mg/kg EMEGchild3
400 mg/kg EPA Screening level
100 mg/kg EMEGchild
100 mg/kg intEMEGchild
|230 mg/kg |
|Not available |
30 mg/kg RMEGchild; 400 mg/kg RMEGadult4
700 - 100,000 mg/kg Background
4000 mg/kg RMEGchild
300 mg/kg RMEGchild
50 mg/kg RMEGchild
300 mg/kg RMEGchild
50 mg/kg Background
300 mg/kg RMEGchild
300 mg/kg RMEGchild
1,000 mg/kg RMEGchild
300 mg/kg RMEGchild
5 mg/kg RMEGchild; 60 mg/kg RMEGadult
200 mg/kg intEMEGchild
20,000 mg/kg RMEGchild
20 mg/kg EMEGchild
400 mg/kg EPA Screening level
100 mg/kg EMEGchild
100 mg/kg intEMEGchild
|Source material||2,4,6-Trinitrotoluene |
|80,500 mg/kg |
30 mg/kg RMEGchild; 400 mg/kg RMEGadult
|Surface water |
(all concentrations were below background metals concentrations)
|373 µg/L |
|50-200 µg/L Secondary Drinking Water Standard |
2,000 µg/L MCL5
300 µg/L Secondary Drinking Water Standard
50 µg/L Secondary Drinking Water Standard
100 µg/L MCL
(metals concentrations were all above background concentrations)
|Carbon disulfide |
|0.63 µg/L |
|1,000 µg/L RMEGchild |
100 µg/L MCLproposed
5 µg/L MCL
6 µg/L MCL; 200 µg/L RMEGchild
5 µg/L LTHA6
100 µg/L CLTHA7
5 µg/L RMEGchild
50-200 µg/L Secondary drinking water standard
2,000 µg/L MCL; 700 µg/L RMEGchild
100 µg/L MCL
1,300 µg/L MCL
300 µg/L CLTHA
50 µg/L CLTHA
100 µg/L MCL
30 µg/L intEMEGchild; 100 µg/L intEMEGadult8
5,000 µg/L CLTHA
2 µg/L MCL
15 µg/L EPA action level
50 µg/L MCL
50 µg/L MCL
1RMEGchild - Reference Dose Based Media Evaluation Guide for a child
2intEMEGchild - Intermediate Environmental Media Evaluation Guide for a child
3EMEGchild - Environmental Media Evaluation Guide for a child
4RMEGadult- Reference Dose Based Media Evaluation Guide for an adult
5MCL - Maximum Contaminant Level
6LTHA - Lifetime Health Advisory
7CLTHA - Child Longer Term Health Advisory
8intEMEGadult - Intermediate Environmental Media Evaluation Guide for an adult
In this section we evaluated the possible pathways for exposure to contamination at Lone Star. Weexamined these possible exposure pathways to determine whether people in the community can beexposed to (or come into contact with) contaminants from the site. Exposure pathways consist offive elements; 1) a source of contamination, 2) transport through an environmental medium, 3) apoint of exposure, 4) a plausible manner (route) for the contaminant to get into the body, and 5) anidentifiable exposed population. Exposure pathways can be completed, potential, or eliminated. Fora person to be exposed to a contaminant, the exposure pathway must be complete. An exposurepathway is considered complete when all five elements in the pathway are present and exposure hasoccurred, is occurring, or will plausibly occur in the future. A potential pathway is missing at leastone of the five elements but may possibly be completed in the future as more data become availableor site conditions change. Eliminated pathways are missing one or more of the five elements andwill never be completed. Table 3 summarizes the exposure pathways considered in our evaluationof this site.
As a result of our site visit observations, and a review of the available data, we concluded thatthere are no plausible exposure situations associated with the ODA that could pose a publichealth hazard at this time. Although chemical contaminants have been found on site in surfacewater, groundwater, sediment, soil, and source material, the current or likely future potential forthe public to be exposed to site contaminants at levels which would present a threat to publichealth is low. An evaluation of each of the pathways that were considered in this assessment is presented below.
Based on available information, sediment from the drainage area south of the ODA does notpresent a hazard to public health. Contaminants were reported below detection limits, belowlevels of health concern or at concentrations similar to background.
Two sediment samples were collected from one location south of the ODA in May and August of1996. This drainage carries surface water from the area south of the ODA to the East Fork of ElliottCreek. Samples collected from surface sediment (0 feet) and subsurface sediment (0.5 feet), wereanalyzed for volatile organic compounds, semivolatile organic compounds, explosives, and metals(Table 1).
With the exception of the detection of acetone at a concentration of 0.22 mg/kg in one 0.5 foot sample, volatile organic compounds were reported to be below their respective detection limits. Semivolatile organic compounds and explosive constituents also were reported to be below their respective detection limits. In general, concentrations of metals in the sediment were low with the exception of aluminum and iron; however, these elements are abundant in the earth's crust (Table 2). For instance natural concentrations of aluminum range from about 700 mg/kg to over 100,000 mg/kg .
CONTAMINANTS OF CONCERN
|E X P O S U R E P A T H W A Y S E L E M E N T S||TIME||COMMENTS|
|POINT OF |
|ROUTE OF |
|Sediment||Volatile and semivolatile organic compounds, and explosives* were reported at concentrations below their respective detection limits. Metals reported at low concentrations, similar to background levels.||Old Demolition Area||Sediment||Drainage area south of the Old Demolition Area||Dermal Contact||Trespassers |
|Based on available information, sediment does not present a public health hazard.|
|Various site activities/ |
|Soil||On-site soil||Ingestion |
|Based on available information, soil at the ODA does not pose a public health hazard.|
|Ordnance debris||Explosives* |
|Lone Star Operations/ODA||Debris||On-site||Ingestion||Trespassers |
|No apparent public health hazard since access to this area is restricted and workers working in this area should be adequately trained and protected.|
|Surface Water||Volatile and semivolatile organic compounds and explosives* were reported at concentrations below their respective detection limits. Metals reported at low concentrations, below levels of health concern.||Old Demolition Area||Surface Water||Surface water from drainage area south of the Old Demolition Area||Dermal Contact||Trespassers |
|Based on available information, surface water does not present a public health hazard.|
|Groundwater||The explosive nitroglycerine, |
the volatile organic compound bis(2-ethylhexyl)phthalate,
|Lone Star Operations||Groundwater|| Residential drinking/ |
|Incidental Ingestion, Inhalation, Dermal Contact||Local area residents using groundwater for domestic purposes||Future||No public health hazard since contaminants have not migrated towards public water supply wells and the groundwater below the site is not used for drinking or other domestic purposes.|
** Volatile organic compounds were analyzed for at the ODA but did not exceed health assessment comparison values.
Based on available information, soil from the ODA does not present a hazard to public health. Contaminants were reported below detection limits, below levels of health concern or atconcentrations similar to background concentrations reported in the literature.
During the Phase IV Remedial Investigation, the nature and extent of chemical contamination in surfacesoil was defined by 50 surface soil samples; 42 composite surface soil (0-6 inches) samples and eightsurface soil samples from hand auger borings. Each composite surface soil sample was collected bycombining soil from four randomly selected locations within a one-acre area. Sampling locations withineach one-acre area were selected by generating random number pairs for x and y coordinates in one-footincrements. Samples were analyzed for explosives and metals. Nitroglycerine, tetryl, and 2,4,6-trinitrotoluene (TNT) were the only explosive compounds detected (Table 2). Nitroglycerine was detectedin six of the 50 samples with concentrations ranging from 6.7 mg/kg to 230 mg/kg. Tetryl was detected inthree of 12 samples at concentrations ranging from 1.95 mg/kg to 6.06 mg/kg. TNT was detected only inone of 12 samples. Contaminated soil at this location does not represent a hazard to the public since publicaccess to this area is not permitted and institutional restrictions such as fences, signs, locked and guardedentrances maintain this restriction. State and federal regulations require that remedial workers beadequately protected and trained in the hazards of working with contaminated soil so that remedialactivities on the site will not present an unreasonable hazard. Additionally, the levels of thesecontaminants detected in the ODA do not currently represent a health hazard from the type of incidentaldermal contact or dust inhalation/ingestion that remedial workers might experience. Metals were reported at concentrations below levels of concern (Table 2).
Based on available information, at present, the contaminants found in the ordnance debris at this sitedo not present a hazard to public health since access to the site is restricted and remedial workersshould be adequately protected and trained in the hazards associated with the debris. In the future, ifaccess to the site changes, the potential public health hazards associated with contaminants in theordnance debris, should it remain on the site, should be reevaluated.
During the Phase IV Remedial Investigation four source material samples were collected in the ODA andanalyzed for explosives and metals . Source material was collected primarily to characterize the typesof chemicals that would be expected to be present in the ODA. To collect the source material, foursparsely vegetated one-acre areas were selected. Within each area, four random locations were chosenusing the x and y coordinate procedure described above. At each sample location, an area with a five-footradius was examined for ordnance debris. A sample of the collected material from each area was analyzedfor metals and explosives. Tetryl was detected in all four of the composite debris samples atconcentrations ranging from 15.9 to 17.8 percent (by weight). 2,4,6-Trinitrotoluene was detected only inone of the four composite debris samples at 8.05 percent (by weight). Various metals such as lead (6,290mg/kg), thallium (30 mg/kg), arsenic (31 mg/kg), manganese (4,360 mg/kg) and zinc (223,000 mg/kg)also were found at elevated levels in the ordnance debris (Table 2). Although several of the contaminantswere reported at concentrations above health assessment comparison values, the ordnance debris is notlikely to present a public health hazard to the community since access to this area is restricted. If theordnance debris were not removed and access to the site was not restricted, the ordnance debris couldpresent a public health hazard if children were tempted to play with and/or collect it. Remedial workersshould be adequately protected and trained in the hazards of the ordnance debris so that remedial activities on the site will not present an unreasonable hazard.
Based on available information surface water from the drainage area south of the ODA, includingEast Fork Elliott Creek, does not present a hazard to public health. Contaminants were reportedbelow detection limits, below levels of health concern or at concentrations similar to background.
The Lone Star facility is situated on a ridge, causing drainage to the north and to the south but theeasternmost edge drains eastward and the westernmost edge drains westward. The ODA is within thesouth-central part of the Lone Star facility. Elevations range from 334 feet above mean sea level along thewest-central side of the ODA to 312 feet above mean sea level at the east-central side. The average slopeis to the south-southeast at about 3 percent . Contamination of surface water is a potential concern atLone Star because water runoff from the site and/or transport of contaminants from other contaminatedareas to surface water may be possible. The surface water bodies which may receive drainage from LoneStar include East Fork Elliott Creek and Lake Wright Patman.
Surface water in the ODA, originating from rainfall, storm water runoff, and from a seep on the southwestpart of the site, collects along two intermittent drainages on the site; one to the south and one to the east. The east drainage discharges into the south drainage which continues for about 1,500 feet before joiningwith East Fork Elliott Creek.
Although water flow in East Fork Elliott Creek is now year-round due to discharge from Lone Star'swastewater treatment plant, possible migration of contaminants via surface water to the Creek would beinfrequent. Surface water flows to the Creek through the south and east drainages or overland only during,or immediately following, a rainfall of greater than 0.6 inches per day (which occurs less than 30 days peryear). During dry periods the extent of surface water is limited to stagnant pools in the southdrainage/seep area. These pools are sustained by groundwater discharge .
During the Phase IV Remedial Investigation, surface water samples were collected from one location inthe south drainage way of the ODA. Samples were collected on May 1, 1996 and August 16, 1996. Twosamples collected from one location were analyzed for volatile organic compounds, explosives, and metals. Another sample, collected from the same location, was analyzed for semivolatile organic compounds. Allvolatile organic compounds, semivolatile organic compounds, and explosives were reported to be belowtheir respective detection limits. Metals were reported at concentrations either below detection limits orbelow levels of concern (Table 2). Iron and aluminum were detected at concentrations above theirrespective secondary drinking water standards. These standards were established to control the aestheticqualities of water and are not health based. Exceeding these secondary drinking water standards by theamounts observed at this site could affect the public's acceptance of the water but would not be expected topresent a public health hazard even if people were using the water.
Based on available data, the public water supplies in the vicinity of Lone Star currently do not containcontaminants associated with the site. Thus, off-site groundwater does not present a public healthhazard. Contaminated shallow groundwater beneath the ODA currently does not present a publichealth hazard since it is not used for potable purposes. If additional on-site groundwater developmentis included in future use plans, it would be prudent to determine the suitability of the water for theproposed uses.
General Hydrogeology and Public Water Supply Wells
The hydrogeologic system associated with Lone Star is the Wilcox Group. This is the water-bearing zoneunder the ODA . The Wilcox Group consists of sand units, silts, clays and lignites. Water transmissiveunits in the Wilcox Group are discontinuous both vertically and laterally; therefore, the water-bearingzones in the Wilcox cannot be classified as a single, homogeneous water-bearing zone. Groundwater,confined in some areas, and unconfined in others, flows south to southeast. The ODA receives very littlegroundwater flow from other areas of Lone Star.
In an earlier remedial investigation , approximately 200 water wells were identified within 2 miles ofthe Lone Star boundary. The report states that most are privately owned wells used for domestic supplyand most are deep aquifer wells installed below the Midway Group to depths of 500 to 800 feet. Shallowwells are generally in alluvial soils near the Red River; and in fact, wells near the northeast corner of LoneStar were installed in Red River alluvial terrace deposits overlying the Midway group. Unlike the deeperwells that are isolated from shallow groundwater, these shallow domestic wells could potentially beinfluenced by shallow groundwater. There are several RCRA regulated sites in the northern half of LoneStar. The potential for contaminants to migrate to off-site wells from these RCRA sites is low.
Lone Star purchases drinking water from the City of Texarkana; the source of this water is primarily LakeWright Patman. Small public water supplies in the vicinity of Lone Star include the City of Redwater andthe City of Maud and mobile home parks. The closest public water supply wells are greater than one milesoutheast of the ODA. These two wells, which supply water to approximately 90 people living in Cody'sMobile Home Park, are 42 and 44 feet deep, drilled in the Midway group. Based on available data, thepublic water supplies in the vicinity of Lone Star currently do not contain contaminants associated with thesite.
On-site Old Demolition Area Monitoring Wells
A total of 18 wells were installed at the ODA at Lone Star; the wells range in depth from approximatelyeight to 44 feet. During the Phase IV Remedial Investigation, 38 shallow groundwater samples collectedfrom these monitoring wells were analyzed for explosives. Ten groundwater samples collected from fourof the monitoring wells were analyzed for volatile organic compounds. Fifty-six groundwater sampleswere collected from 13 monitoring wells and analyzed for metals; 28 of the samples were unfiltered and28 were filtered with metal concentrations reported as dissolved. Maximum reported concentrations wereobtained from the unfiltered samples (Table 2).
Volatile organic compounds, semivolatile organic compounds, and explosives were detected in thegroundwater samples below levels of public health concern. Nitroglycerine was detected at a maximumconcentration of 108 µg/L, a concentration greater than the recommended lifetime health advisoryconcentration for this contaminant. The maximum concentrations of aluminum, iron, and manganesedetected in the groundwater were greater than background concentrations and greater than EPA'ssecondary drinking water standards for these contaminants; however, these standards are set for aestheticreasons and are not necessarily health based. Manganese is an essential dietary nutrient; the World HealthOrganization (WHO) has estimated the average dietary intake of manganese to range from approximately2,000 to 8,800 micrograms per day. The Food and Nutrition Board of the National Research Council hasestablished "estimated safe and adequate daily dietary intake levels" for this nutrient that range from 300micrograms per day for infants to 5,000 micrograms per day for adults. The WHO has concluded that8,000 to 9,000 micrograms per day is "perfectly safe" for adults. We would not anticipate the levels ofmanganese in the water to pose a threat to public health; particularly since the water is not used for potablepurposes.
Vanadium was detected in nine of the 28 unfiltered groundwater samples at concentrations ranging from9.46 micrograms per liter to 144 micrograms per liter. The maximum detected value (144 microgramsper liter) exceeds the health based screening value for this contaminant derived using ATSDR'sintermediate oral minimal risk level (MRL). Assuming a 70 kg adult consumption of 2 liters per day, themaximum concentration of 144 µg/L is equivalent to a daily dose of 0.004 milligrams vanadium perkilogram body weight (0.004 mg/kg/day). The MRL for this contaminant (0.003 mg/kg/day) is based ona study in which selected concentrations of vanadium were administered to rats in their drinking water forthree months. The animals showed mild histological changes in kidneys, lungs, and spleen that becomeprogressively more severe with increased dosages. A No Observable Adverse Effects Level (NOAEL) wasidentified and used to establish the MRL for humans. To establish the MRL the NOAEL was divided byan uncertainty factor of 100 (10 for extrapolation from animals to humans, and 10 for human variability). Vanadium only was detected in 25% of the samples; most of the samples had reported concentrationsbelow the health based screening level. Although the maximum concentration of vanadium detected in thegroundwater exceeded the health based screening level, we would not expect the vanadium in this water toresult in observable adverse health effects. Additionally, this water is not currently being used for drinkingor other domestic purposes. The maximum concentration of lead detected in the groundwater (310 µg/L)exceeded background concentrations of lead in groundwater and the EPA action level for this contaminant(15 µg/L). If this water were regularly consumed by children the presence of lead in the water could posea health threat. Since this water is not currently being used for drinking or other domestic purposes, thelead and other constituents in the groundwater currently do not present a public health hazard.