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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 healtheffects if people actually come into contact with them. People may be exposed to chemicals bybreathing, eating, or drinking a substance containing the contaminant or by skin (dermal) contactwith a substance containing the contaminant.

When people are exposed to chemicals, the exposure does not always result in adverse healtheffects. 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 allowedto occur; 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,nutritional status, genetics, life style, and health status of the exposed individual influence how theindividual absorbs, distributes, metabolizes, and excretes the contaminant. These factors andcharacteristics influence whether exposure to a contaminant could or would result in adverse health effects.

Environmental Contamination

In preparing this public health assessment, we relied on the information provided in the referenceddocuments. The Agency assumed that adequate quality assurance and quality control measureswere followed with regard to chain-of-custody, laboratory procedures, and data reporting. Thevalidity of the analyses and the conclusions drawn in this document are determined by theavailability and reliability of the referenced information.

Groundwater and surface soil sampling data were collected at each of the three facilities todetermine the extent that chromium contamination has spread off of the site. Drinking watersamples and soil samples collected were reviewed and validated by EPA Region 6 according to allappropriate guidelines (the USEPA Contract Laboratory Program Statement of Work forInorganic Analysis, Organic Analysis, and National Functional Guidelines for Organic DataReview and Inorganic Analyses).

Tables listing available environmental sampling data for each of the three facilities associated withthis NPL site are available in Appendix D. The most recent groundwater sampling data for totalchromium and hexavalent chromium was completed by EPA in August of 1996 (Appendix D,Table 1). During this sampling event, samples were collected from monitoring wells, residentialwells, and industrial water wells in the vicinity of the three facilities. Additional groundwater data(for volatile organic compounds, semi-volatile organic compounds, and metals) are available foreach of the three facilities (Appendix D, Table 2). Surface soil sampling data are presented inAppendix D, Tables 3 (Leigh Metal Plating), 4 (National Chromium Corporation), and 5(Machine and Casting, Inc.).

Table 2 through 5 present the maximum concentrations reported for each of the contaminantsdetected. ATSDR comparison values for each of the contaminants also are listed in the tables. Comparison values are media specific contaminant concentrations used to select contaminants forfurther evaluation. Inclusion of a contaminant in a table or the fact that a contaminant exceeds acomparison value does not imply that the contaminant represents a threat to public health. Ageneral explanation of comparison values is provided in the box below.

Explanation of Comparison Values








The maximum permissible level of a contaminant in a public water system.

The Cancer Risk Evaluation Guide is an estimated contaminant concentration that would result in no more than one excess cancer in a million (10E-6) persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors (CSFs).

Environmental Media Evaluation Guides are based on ATSDR's minimal risk levels (MRLs). An MRL is an estimate of a daily human exposure to a chemical that is likely to be without an appreciable risk for noncarcinogenic effects over a specified duration of exposure (acute, intermediate, chronic).

Similar to the EMEG but derived from EPA's reference dose. It is the concentration in a specific media at which daily human exposure is unlikely to result in adverse noncancerous effects.

The Lifetime Health Advisory represents a contaminant concentration that EPA considers to be protective of noncarcinogenic health effects during a lifetime (70 years) of exposure.

A subscript child adjacent to the EMEG or RMEG indicate that the comparison value was determined using a child exposure scenario. Child EMEGs and RMEGs are lower for children.

Levels reported to exist in an uncontaminated environment. In this document background represents sampling data in the northwest Odessa area.

Table 1.

Health Hazard Situation-Sprague Road Groundwater Plume Site


Leigh Metal Plating Groundwater Off-site residences Ingestion Local area residents using well water for domestic purposes.
People who used to work at Leigh Metal, National Chromium, and Machine and Casting.
In the past, workers and local residents used groundwater from the vicinity of these facilities for potable and other domestic purposes. The majority of the people have been switched to city water; however, at least one resident and possibly others still use the water. We estimate the current exposed population to be less than 10 persons. Additional people could be at risk for exposure to the contaminated groundwater if the existing groundwater contamination is not remediated.
National Chromium Corporation
Machine and Casting, Inc.
Surface Soil Chromium Leigh Metal Plating Surface Soil On-site Ingestion
Dermal contact
On-site workers
In the past workers on the site may have been exposed to chromium contaminated soil. An unknown number of trespassers on these sites also may be exposed to contaminated soil.
National Chromium Corporation On-site

Exposure Pathways

In this section we evaluated the possible pathways for exposure to contamination at SpragueRoad Groundwater Plume site. We examined these possible exposure pathways to determinewhether people in the community can be exposed to (or come into contact with) contaminantsfrom the site. Exposure pathways consist of five elements; 1) a source of contamination, 2)transport through an environmental medium, 3) a point of exposure, 4) a plausible manner (route)for the contaminant to get into the body, and 5) an identifiable exposed population. Exposurepathways can be complete, potential, or eliminated. For a person to be exposed to a contaminant,the exposure pathway must be complete. An exposure pathway is considered completed when allfive elements in the pathway are present and exposure has occurred, is occurring, or will plausiblyoccur in the future. A potential pathway is missing at least one of the five elements but maypossibly be complete in the future as more data become available or site conditions change. Eliminated pathways are missing one of more of the five elements and will never be complete. The exposure pathways considered in our evaluation of this site are summarized in Table 1

Evaluation of Possible Groundwater Exposure Pathways

Summary: As a result of our site visit observations, and a review of the available data, weconcluded that chromium in the groundwater presents a public health hazard. In the past, on-site workers and local residents used contaminated groundwater for drinking and other domesticpurposes. At present, we have identified at least one residence that continues to use thegroundwater as a source of drinking water. In the absence of remediation the groundwaterplume could extend towards other residences where groundwater continues to be a source ofdrinking water. A review of the groundwater pathway considered in this assessment is presentedbelow.

    General Hydrogeology and Public Water Supply Wells

The major hydrologic units which contain potable water in the vicinity of the Sprague RoadGroundwater Plume NPL site are the Ogallala Formation and the Trinity Sand. In general theOgallala is hydrologically connected with the underlying Trinity but has little saturated thickness. Water in the Ogallala Aquifer flows to the south and southeast, except in areas where there isheavy pumping of the wells, then the direction of flow is toward the area of withdrawal. Generally, the depth to the water table is about 85 feet below the ground surface and the base ofthis aquifer is about 145 feet below ground surface. Within the site area, the Ogallala Aquifer hasa saturated thickness of 60 feet [4]. The hydraulic characteristics of the Ogallala are moreimportant than the amount of water it holds since it may potentially act as a medium throughwhich contaminants may enter the underlying Trinity aquifer. The Trinity sand underlying theOgallala is the major aquifer in the vicinity of this NPL site. Up to 70 feet of saturation may bepresent in these sands, sandstones, and gravel. The city of Odessa has wells which penetrate theentire Trinity section. These wells average a yield of 167 gallons per minute.

Until September 1993 numerous business and residences all were on individual private water wells(Appendix C). Following discovery of chromium in residential and individual wells atconcentrations above the MCL, the City/County extended water service to the area affected bythe chromium plume; however, some residents still obtain water from individual wells. TheTNRCC and the EPA have done extensive work to identify water well use in the vicinity of thesite and the extent of chromium contamination at levels above the MCL. In addition, the cityclosed some public water supply wells within 4 miles of the site in response to low water outputand concern about the chromium problem.

The City of Odessa receives its public water supply from combined surface and groundwatersources. On a yearly average, surface water supply from Lake O.H. Ivie provides approximately90 percent of the total water volume. The rest is provided by groundwater. The twenty-fiveactive public supply wells which supply this groundwater all are within four miles of the SpragueRoad Groundwater Plume Site.

    Contamination and Public Health Implications

Bis(2-ethylhexyl)phthalate (BEHP), 1,2-dichloroethane (1,2-DCA), and 1,1-dichloroethene (1,1-DCE) all were detected in groundwater at maximum concentrations above their respectivecomparison values. BEHP was detected above its CREG in groundwater below LMP and M&C;1,2-DCA was detected above its CREG in groundwater below LMP; and 1,1-DCE was detectedabove its CREG in groundwater below NCC . Although these contaminants were detected atconcentrations above their respective CREGs, based on EPA's substance specific cancer potencyvalues and a maximum exposure scenario (drinking two-liters of water per day for 70 years) wewould estimate there to be no apparent increased lifetime risk for cancer associated with these contaminants.

Chromium was the main contaminant detected in groundwater at concentrations of potentialpublic health concern. The highest reported concentration of chromium (17.4 mg/L ) wasmeasured in groundwater from an on-site monitoring well on the National Chromium site duringthe August 1996 EPA sampling event. Concentrations of chromium above EPA's MCL (0.1mg/L) were measured in 19 of the water wells sampled (Appendix D, Table 1; Appendix B, Figure 2b).

Chromium exists in the environment primarily in two forms. Trivalent chromium (chromium [III])occurs naturally in the environment and is an essential nutrient that helps the body use sugar,protein, and fat. An intake of 50 to 200 micrograms (g) per day is recommended for adults. Hexavalent chromium (chromium [VI]) generally comes from industrial processes. Based onEPA's reference dose(RfD) of 0.005 mg/kg/day, chromium [VI] is about 200 times more toxicthan chromium [III]; however, confidence in the RfD is low, because it is based on an animalstudy in which there was a lack of toxic effect even at the highest dose. The reference dose forchromium [VI] was derived by dividing the highest observed NOAEL (2.4 mg-Cr[VI]/kg/day forone year) by an uncertainty factor of 500.

Ingesting a small amount of chromium [VI] generally is not harmful; however, accidental orintentional ingestion of large amounts can cause upset stomach, ulcers, kidney and liver damage,and even death. Ingestion of chromium has not been shown to cause cancer, although inhalationof chromium [VI] has been demonstrated to cause lung cancer. Dermal exposure to chromiumcan cause skin rashes in sensitive persons [8]. For acute exposure in humans LOAELs for seriouseffects (gastrointestinal, hepatic, renal, and death) range from approximately 4.1 to 29 mg/kg/day. Many of these effects were reported after a single dose. Less serious effects (enhancement ofdermatitis) have been reported after acute exposure to doses as low as 0.036 mg/kg/day. Forchronic-duration exposure an oral LOAEL for gastrointestinal and hematological effects of 0.57mg/kg/day has been reported for humans [8]. If an adult were to drink water containing 17.4 mgchromium/L (the highest concentration measured at this site) that person would be exposed tojust slightly less than the concentration which is known to cause gastrointestinal andhematological effects; a child would be exposed to more than 0.57 mg/kg/day.

Much of the data provided did not specify the type of chromium detected; however, during theAugust 1996 sampling event both total chromium and hexavalent chromium were measured and inmost instances hexavalent chromium accounted for over 90 percent of the total chromium. In theinterest of protecting public health, when not specified, we assumed the reported concentrationsto be chromium [VI].

At this site, at least two households continue to use well water for drinking and other householdpurposes even though they are aware that the chromium concentrations exceed the maximumcontaminant level of 0.1 mg/L. The measured concentration of chromium in one of thehouseholds was 0.3 mg/L; the concentration of chromium measured in August 1996 in the otherhousehold was 0.358 mg/L. The concentration of 0.3 mg/L is equal to a dose of 0.02 mg/kg/day. This is four times greater than the reference dose of 0.005 mg/kg/day. One householdimmediately south of the National Chromium plume is using one well for drinking and otherhousehold uses; in August of 1996, the concentration of chromium in this well that was 0.049mg/L. A second well, not currently supplying the household with drinking water had a chromiumconcentration of 0.165 mg/L. The resident had considered connecting the second well to the first;however, EPA recommended against this until the chromium concentration in the groundwater was reduced.

Accidental or intentional swallowing of large amounts of chromium (VI) can cause stomachupsets, ulcers, convulsions, kidney and liver damage, and even death. In a cross sectional studyconducted in 1965 of 155 people whose well water contained 20 mg chromium (VI)/L (pollutionfrom an alloy plant in the People's Republic of China), associations were found between drinkingthe contaminated water and oral ulcer, diarrhea, abdominal pain, indigestion, and vomiting,leukocytosis and immature neutrophils. The 20 mg chromium (VI)/L concentration wasestimated to be equivalent to a dose of 0.57 mg chromium (VI)/ kg body weight/ day.

Liver damage, evidenced by jaundice, increased bilirubin, and increased serum lacticdehydrogenase, were described from cases of people ingesting chromium (VI) compounds. Acuterenal failure, characterized by proteinuria, hematuria, followed by anuria also has been reported. An expert panel recently concluded that chromium concentrations below 35 mg/L in water are notlikely to cause dermatitis.

Based on the maximum concentration of chromium identified in the groundwater (17.4 mg/L), itwould be possible for a person drinking this water to exceed the dose associated withgastrointestinal effects ([17.4 mg/L * 1 L/day] 35 kg-BW) and based on the concentrationsreported in wells currently used for drinking water, the reference dose could be exceeded both bychildren and adults. At this time, groundwater contamination associated with the Sprague RoadGroundwater Plume site presents a public health hazard.

Evaluation of Possible Soil Exposure Pathways

Summary: As a result of our site visit observations, and a review of the available data, weconcluded that contaminated soil associated at LMP presents a potential public health hazard. Chromium levels in the soil are high and there is evidence of trespassing on the site; however,we could not determine with any degree of certainty whether people were frequenting thecontaminated area. A review of the soil pathway considered in this assessment is presented below.

On-site and offsite surface soil (0-4 inches) were collected from each of the facilities associatedwith the Sprague Road Groundwater Plume site. Samples were analyzed for volatile organiccompounds, semi-volatile organic compounds, pesticides, and metals. Although severalcontaminants were reported at concentrations above their respective CREGs, we would notexpect exposure to these compounds at the reported concentrations to result an a significantincreased lifetime risk for cancer. In 1995 at NCC, lead was detected at a maximumconcentration of 1,300 mg/kg east of the building. While 1,300 mg/kg exceeds the comparisonvalue for this contaminant, exposure possible to soil at this site would be infrequent and wouldnot be likely to present a threat to public health. In addition, the EPA removed more than 2,600tons of contaminated soil from NCC in 1996.

Chromium was detected at concentrations well above the chromium (VI) noncarcinogeniccomparison value both at LMP (36,500 mg/kg) and NCC (42,400); however, in 1996, the EPAremoved approximately 2,600 tons of contaminated soil from NCC. We are not aware of anyremoval actions at LMP. In most soils chromium is present in the chromium (III) state; however,since speciation was not available we assumed the chromium at this site to be the more toxicchromium (VI). There was evidence of trespassing at LMP; thus, access to the contaminatedareas by trespassers is possible. Although in a typical trespasser scenario, contact with the soilwould be short-term and infrequent, we estimate that a 35 kg child (approximately 12 years old)ingesting as little as 35 milligrams of soil per week would exceed the reference dose. Of coursethis estimate is based on an exposure point concentration of 36,500 mg/kg a single point value;the actual exposure point concentration most likely is lower.

On-site air data were not available for our review; although windblown soils may have been aconcern in the past when contaminated soils were piled up at Leigh Metal Plating. The August1995 Site Screening Inspection (SSI) Report for Leigh Metal Plating reported that although airsamples were not taken at the site, results of surface soil samples collected from the site (1995)were used to assess potential for releases to occur to air [5]. This SSI also states that there are noknown observed releases of hazardous substances to the air from Leigh Metal Plating [5].


Community Health Concerns

In an attempt to collect community health concerns related to the Sprague Road GroundwaterPlume site, we contacted several different agencies and individuals by telephone, including theregional offices of both the Texas Department of Health (TDH Region 9) and the Texas NaturalResource Conservation Commission. In addition to state agencies we contacted local healthdepartment staff and local citizens. EPA and the Texas Department of Health held two OpenHouse meetings for community members in March and July of 1998. Approximately 15 peopleattended each of the meetings. Community concerns were compiled from those attending themeetings and from those individuals we spoke with while going door to door in the neighborhood.We received the following health concerns. Several concerns were received pertaining to theOdessa Drum site; these concerns will be addressed as a separate health consultation.

  1. Is my water safe to drink?

    If your water has been tested for chromium concentration and it is below the maximum contaminant level of 0.1 milligrams chromium per liter of water, it should be safe to drink with respect to the chromium concentration. If your water has not been tested and you live close to the contaminated areas (see figure 2b), you should have your water tested.

  2. If I use my well water to irrigate will chromium build up in the vegetables?

    Generally root crops may take up some chromium from highly contaminated soils; however, most of the chromium is retained in the roots with only a fraction moving to the above parts of edible plants. Thus, based on available information, leafy vegetables and above ground fruits and vegetables are not likely to take up chromium in concentrations that would cause health problems to people eating those fruits and vegetables.

  3. Is it safe to eat vegetables from my garden?

    Although the only way to definitively answer this question would be to have your vegetables tested, based on available information it does not appear likely that leafy vegetables and above ground fruits and vegetables will take up chromium from the soil in sufficient quantities to cause health problems.

  4. If I use my well water to irrigate will chromium build up in the dirt in my yard?

    Irrigating soil with water contaminated with chromium can cause chromium to be added to the soil. The amount of chromium that accumulates in the soil depends upon several factors: 1) the concentration of chromium in the water, 2) how often the water is added, 3) how much water is used during each watering cycle, 4) the size of the area over which the water is added, and 5) how deeply the water penetrates into the soil (the deeper the penetration the lower the accumulated concentration). The public health implications of chromium added to the soil depend upon the concentration of the chromium in the soil, the type of chromium (III or VI), and the amount of that soil that you ingest. Using the following assumptions:

    Weight of soil = 35 kg per cubic foot

    Area watered

    = 100 square feet


    = 1 foot

    Frequency of watering

    = 3 times per week 50 weeks per year

    Amount of water per event

    = 100 gallons

    Chromium conc. in water

    = 300 g/L (0.3 mg/L)

    Type of chromium

    = (VI)

    We estimate that it would take over 60 years for the chromium concentration in the soil to exceed the soil screening value for children. It would take over 800 years to exceed the soil screening level for adults. If all of the above conditions were the same, but the chromium concentration in the water was 0.9 mg/L, then we estimate that it would take 20 years for the chromium concentration in the soil to exceed the screening value for children. It would take 267 years to exceed the soil screening level for adults.

  5. We don't know how long the water was contaminated before they told us to stop using it and put us on city water; since I only have one kidney, I want to know if my health could be affected by having used the contaminated water for so long.

    Short-term exposure to large amounts of chromium through ingestion has caused kidney damage both in humans and animals; however, long-term exposure to low levels of chromium has not. Based on the maximum values reported in the groundwater, it is not likely that the chromium in the water would effect your kidney; however, we cannot say this with absolute certainty. Long-term exposure to other metals such as cadmium can result in kidney toxicity and smoking is a significant source of cadmium.

  6. I was diagnosed with breast cancer could this be due to the site?

    Chromium has not been associated with breast cancer; other risks factors such as high fat diets have.

  7. None of us have noticed health problems but we thought it made the dogs sick; one dog had a blood disease and hair loss.

    Exposure to chromium (VI) compounds has been reported to affect the blood of humans. Blood effects were not observed in rats fed varying amounts of chromium in their diets. At this time it would be difficult if not impossible to determine if exposure to chromium was responsible for the dogs' past illnesses.

  8. Could my diabetes be related to the site?

    Not likely. In fact, a deficiency of chromium (III) in the diet can impair the body's ability to use sugars and other nutrients properly and could lead to a diabetic like condition. Exposure to chromium (VI) has not been associated with diabetes.

  9. Could my bronchial asthma be related to the site?

    Not likely. Although air data were not available, based on available information it does not appear that air levels would be sufficient to cause adverse health conditions.

Child Health Initiative

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. They 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, resulting in higher doses of chemical exposure per 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 decision, and access to medical care.

ATSDR evaluated the likelihood for children living in the vicinity of the Sprague Road Groundwater Plume site to be exposed to site contaminants at levels of health concern. ATSDR identified situations in the past in which children were likely to have been exposed to chromium contamination in groundwater. Children currently are not likely to be exposed to chromium in groundwater unless the extent of the contamination spreads to water wells which are being used by families with children. The maximum reported concentration of chromium in soil at LMP was very high and access to the site by children is possible. If children were to frequently trespass on this site they could be at risk. The five foot pit on the National Chromium Corporation site presents a physical hazard to small children who may trespass on the site.

Health Outcome Data

Health outcome data (HOD) record certain health conditions that occur in populations. These data can provide information on the general health of communities living near a hazardous waste site. It also can provide information on patterns of specified health conditions. Some examples of health outcome databases are tumor registries, birth defects registries, and vital statistics. Information from local hospitals and other health care providers also may be used to investigate patterns of disease in a specific population. Other than routinely collected birth and death data, no additional information pertaining to health outcome data for residents living in the vicinity of the site was available.

We checked the Bureau of Epidemiology files, Health Studies Program Files and checked with both the local and regional public health departments. No special studies have been conducted other than the collection of routine birth and death records.

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