PUBLIC HEALTH ASSESSMENT
STATE ROAD 114 GROUNDWATER PLUME
LEVELLAND, HOCKLEY COUNTY, TEXAS
- In the past 1,2-dichloroethane and other contaminants of concern posed a public health hazard to those using contaminated well water.
- Currently the plume of contaminated groundwater poses no apparent public health hazard either because wells are on individual treatment systems or exposure to the contaminants of concern in wells without a treatment system is not high enough to result in health problems.
- In the future, contaminants in the groundwater could migrate toward additional wells and pose a public health hazard if left untreated.
- EPA/TNRCC are developing a remedial action plan for the State Road 114 GroundwaterPlume NPL site.
- TDH/ATSDR will review additional groundwater monitoring data for this site as theybecome available.
- The agencies will work with individuals whose wells have been affected to minimizeexposure.
- TNRCC/EPA should continue to provide an alternate water source for drinking/bathing/showering to individuals whose wells contain contaminants at levels ofpublic health concern.
PREPARERS OF THE REPORT
Susan L. Prosperie, M.S., R.S.
Environmental Epidemiology and Toxicology Division
John F. Villanacci, Ph.D.
Environmental Epidemiology and Toxicology Division
Health Assessment Technician
Environmental Epidemiology and Toxicology Division
ATSDR Regional Representative
Senior Regional Representative
ATSDR - Region 6
This State Road 114 Groundwater Plume Public Health Assessment was prepared by the TexasDepartment of Health under a cooperative agreement with the Agency for Toxic Substances andDisease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was initiated.
Alan W. Yarbrough
Technical Project Officer, SPS, SSAB, DHAC, ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health Assessment and concurs with its findings.
Lisa C. Hayes
for Chief, State Programs Section, SSAB, DHAC, ATSDR
- Environmental Protection Agency. State Road 114 Groundwater Plume Texas EPA ID#TXSFN0605177. Site Description at Listing. July, 1999.
- HRS Documentation Record. State Road 114 Groundwater Plume National Priorities Listsite, Hockley County, Texas. TXS FN0 605 177. Prepared by the Texas Natural ResourceConservation Commission Site Evaluation/Remediation/Restoration Section Superfund SiteDiscovery and Assessment Staff in cooperation with the U.S. Environmental ProtectionAgency Region VI. July 1999.
- Texas Natural Resource Conservation Commission. Expanded Site Inspection Report forMotor Fuels Corporation site, TX0001093152, Levelland, Hockley County, Texas. Prepared in cooperation with the U.S. Environmental Protection Agency. September 1997.
- Texas Natural Resource Conservation Commission. Screening Site Inspection Report,Addendum to Preliminary Assessment Report for Motor Fuels Corporation siteTX0001093152, Levelland, Hockley County, Texas. Prepared in cooperation with the U.S.Environmental Protection Agency. October 1996.
- U.S. Environmental Protection Agency. Superfund Site Strategy Recommendation-Region6. Motor Fuels Corporation. CERCLIS ID # TX0 001 093 152. August 19, 1997.
- Agency for Toxic Substances and Disease Registry. Health Consultation. Motor FuelsCorporation, Levelland, Hockley County, Texas. CERCLIS No. TX0001093152. December 11, 1997.
- Agency for Toxic Substances and Disease Registry. Health Consultation, Residential Well I, Motor Fuels Corporation Levelland, Hockley County, Texas. CERCLIS No.TX0001093152. September 30, 1998.
- Agency for Toxic Substances and Disease Registry. Health Consultation, Residential Well II, Motor Fuels Corporation Levelland, Hockley County, Texas. CERCLIS No.TX0001093152. September 30, 1998.
- Agency for Toxic Substances and Disease Registry. Health Consultation, Residential Well III, Motor Fuels Corporation Levelland, Hockley County, Texas. CERCLIS No.TX0001093152. September 30, 1998.
- Agency for Toxic Substances and Disease Registry. Health Consultation, State Highway114 Groundwater Plume (a/k/a Motor Fuels Corporation), Levelland, Hockley County, Texas. CERCLIS No. TXSFN0605177. September 29, 1999.
- Federal Register / Vol. 64, No. 204 / Friday, October 22, 1999 / Rules and Regulations pp 56966 - 56973.
- Texas Department of Health. Record to the File. Site Visit Notes to State Road 114Groundwater Plume NPL site. Susan L. Prosperie. November 19, 1999.
- 1990 U.S. Census Data Database C90STF3BandC90STF1A, Summary Level State-Place.
- County Population Estimates for July 1, 1999. Population Estimates Program, Population Division, U.S. Census Bureau, Washington, DC 20233.
- Texas Department of Health. Record of Communication. Susan L. Prosperie, TDH toFarmer's Co-op regarding current number of employees. June 22, 2000.
- Agency for Toxic Substances and Disease Registry. Public Health Assessment GuidanceManual. 1992.
- Daniel B. Stephens & Associates, Inc. Groundwater Monitoring Report prepared forTNRCC Superfund Site Discovery and Assessment Team. State Road 114 Groundwater Plume. Levelland, Texas. August 30, 1999.
- Daniel B. Stephens & Associates, Inc. State Road 114 Groundwater Plume Second Quarter Fiscal Year 2000 Water quality Sampling. Volume 1. Prepared for Texas NaturalResource Conservation Commission. April 26, 2000.
- City of Levelland, 1998 Drinking Water Quality Report, http://www.ci.levelland.tx.us/water_quality.htm 11/18/99.
- Agency for Toxic Substances and Disease Registry (ATSDR). May 1994. Toxicologicalprofile for 1,2-dichloroethane. Atlanta, GA: U.S. Department of Health and HumanServices, Public Health Service.
- Smith, AH., Hopenhayn-Rich, C., Bates, MN., Goeden, HM., Hertz-Picciotto, I., Duggan,HM., Wood, R., Kosnett, MJ., Smith, MT. 1992. Cancer risk from arsenic in drinkingwater. Environ. Health Perspect. 97:259-267.
- U.S. Environmental Protection Agency. 1984. Health assessment document for inorganicarsenic. Final Report. Research Triangle Park, NC: U.S. Environmental ProtectionAgency. EPA-6008/83-021F.
- Tseng, WP., Chu, HM., How, SW., Fong, JM., Lin, CS., Yeh, S. 1968. Prevalence of skin cancer in an endemic area of chronic arsenism in Taiwan. J. Natl. Cancer Inst. 40:453-463.
- Tseng, WP. 1977. Effects and dose-response relationships of skin cancer and Blackfootdisease with arsenic. Environ. Health Perspect. 19:109-119.
- U.S. Environmental Protection Agency. 1988. Special report on ingested inorganic arsenic: Skin cancer; nutritional essentiality. Washington, DC: U.S. Environmental Protection Agency, Risk Assessment Forum. EPA/625/3-87/013.
- Agency for Toxic Substances and Disease Registry (ATSDR). February 1996.Toxicological profile for manganese. Atlanta, GA: U.S. Department of Health and HumanServices, Public Health Service.
- IRIS, 1996. Integrated Risk Information System. U.S. Environmental Protection Agency, Office of Health and Environmental Assessment, Environmental Criteria andAssessment Office. Cincinnati, OH.
- Dimond EG, Caravaca J, Benchimol A. 1963. Vanadium: Excretion, toxicity, lipid effect in man. Am J Clin Nutr 12:49-53.
- Agency for Toxic Substances and Disease Registry (ATSDR). July 1992. Toxicologicalprofile for vanadium. Atlanta, GA: U.S. Department of Health and Human Services, PublicHealth Service.
- Domino JL, Llobet JM, Tomas JM et al. 1985. Short-term toxicity studies of vanadium in rats. J Appl Toxicol 5:418-421.
- Agency for Toxic Substances and Disease Registry (ATSDR). August 1995. Toxicologicalprofile for benzene. Atlanta, GA: U.S. Department of Health and Human Services, PublicHealth Service.
|ATSDR||Agency for Toxic Substances and Disease Registry|
|CERCLA||Comprehensive Environmental Response, Compensation and Liability Act of 1980|
|CLHA||Child Longer-term Health Advisory|
|CREG||Carcinogenic Risk Evaluation Guide|
|EMEG||Environmental Media Evaluation Guide|
|EPA||U.S. Environmental Protection Agency|
|ESI||Expanded Site Investigation|
|HAC||Health Assessment Comparison Value|
|HOD||Health Outcome Data|
|LOAEL||Low Observable Adverse Effects Level|
|LTHA||Lifetime Health Advisory|
|MCL||Maximum Contaminant Level|
|MCLG||Maximum Contaminant Level Goal|
|µg/L||Micrograms per Liter equals ppb or Parts per Billion|
|mg/kg||Milligrams per Kilogram|
|MRL||Minimal Risk Level|
|NOAEL||No Observable Adverse Effects Level|
|NPL||National Priorities List|
|PHA||Public Health Assessment|
|ppb||Parts per Billion|
|RMEG||Reference Dose-based Media Evaluation Guide|
|SARA||1986 Superfund Amendments and Reauthorization Act|
|TDH||Texas Department of Health|
|TWC||Texas Water Commission|
|TNRCC||Texas Natural Resource Conservation Commission|
Range of Concentrations Measured (µg/L)
|Health Assessment Comparison Values (µg/L)|
|Private/Individual Water Wells||Business Water Wells||Municipal Water Wells|
|Volatile Organic Compounds|
|1 CREG A; 5 MCL |
0.4 CREG B2; 2000/7000 intEMEG; 700 CLHA; 5 MCL
100 MCL Total Trihalomethanes
|30/10 chronic EMEG; 0.02 CREG A; 50 MCL |
B2; 15 EPA Action Level
30/100 intermediate EMEG
Long term exposure to low doses of 1,2-dichloroethane has caused kidney disease and multiple tumortypes in animals. Based on sufficient animal studies but inadequate human studies, 1,2-dichloroethanehas been classified as a probable (Group B2) human carcinogen . The concentration of 1,2-dichloroethane in water from both residential and business wells exceeded the CREG value for thiscontaminant. The highest measured concentration in the residential wells was 23 µg/L, while the highestmeasured concentration in the business wells was 69 µg/L.
Based on these data (assuming the levels do not increase) and on EPA's cancer slope factor for 1,2-dichloroethane, we estimate that chronic ingestion (30 years) of two (2) liters of this water each day (350days per year) would not result in any apparent increased lifetime risk for the development of cancer. Insome of the residences the theoretical excess lifetime risk for developing cancer could have been highersince people also could have been exposed through inhalation and dermal contact. The actual magnitudeof this increase would depend upon the actual concentrations in the air and water as well as the length oftime over which the exposures occurred. Using a worst case scenario, exposure to this contaminantthrough all pathways combined would result in a low increased lifetime risk for developing cancer. TNRCC has installed individual treatment systems on each of the residential wells in which contaminants were found above the MCL.
A large number of epidemiologic studies and case reports provide evidence that ingestion of arsenicincreases the risk of developing cancer. The most common effect is an increased risk of multiple skincancers. Some of the skin cancers develop from hyperkeratotic warts or corns characteristic of chronicarsenic exposure. Multiple basal cell carcinomas also may occur, usually from cells not associated withhyperkeratinization. In most cases, skin cancer develops only after prolonged exposure; however, severalstudies have reported skin cancer in people exposed for less than one year. Liver, bladder, kidney, andlung cancer also have been associated with oral exposure to arsenic , but these associations are lesswell established and currently not suitable for inclusion in risk estimates.
Based on epidemiological studies, the EPA has classified arsenic as a Group A "known human"carcinogen. This classification is based on consistent evidence of increased risk of lung cancer in workersexposed to airborne arsenic-contaminated dust  and on the clear dose-dependent relationship betweeningested arsenic and skin cancer [23, 24].
Arsenic was detected above its carcinogenic risk evaluation guide both in residential wells and in one ofthe business wells. Based the current data (assuming the levels do not increase) and on EPA's cancerslope factor for arsenic, we estimate that chronic ingestion (30 years) of two (2) liters of this water eachday (350 days per year) could result in a theoretical low to moderate increased lifetime risk for thedevelopment of cancer.
There is some evidence that the body may detoxify arsenic suggesting that the dose-response curve forarsenic may be non-linear at low doses. Since EPA derived the cancer slope factor for arsenic using amodel that assumes that the dose-response curve is linear at low doses, the slope factor based on the linearmodel may over estimate cancer risks at low doses. The EPA has concluded that although the currentslope factor might over estimate low dose risk, data are too limited to permit a quantitative adjustment of the slope factor .
Excess exposure to manganese can be harmful to human health. A combination of symptoms resulting ina disease known as manganism has been observed in mining and steel workers after long-term exposure tohigh levels of manganese dust in the air. These symptoms include weakness, abnormal gait, ataxia,muscular hypotonicity, and a fixed facial expression. Manganism occurs when too much manganeseadversely affects the brain. Although some of the symptoms of manganism can be treated, the damagethat occurs to the brain is permanent .
It is not known whether eating or drinking too much manganese can cause manganism. There is onestudy indicating a statistically significant difference in neurologic test scores between people from an areawith high levels of manganese in well water compared with people from another area with low levels ofmanganese in well water. The concentration of manganese in the water from the high concentration arearanged from 1,600 to 2,300 µg/L; however, because of other limitations this study could not be used todetermine a quantitative dose response relationship for the toxicity of manganese in humans .
Manganese is an essential dietary nutrient; the World Health Organization (WHO) has estimated theaverage dietary intake of manganese to range from approximately 2,000 to 8,800 µg/day. The Food andNutrition Board of the National Research Council has established "estimated safe and adequate dailydietary intake levels" for this nutrient that range from 300 µg per day for infants to 5,000 µg/day foradults. The WHO had concluded that 8,000 to 9,000 µg/day is "perfectly safe" for adults . Based onestimates of what is considered safe the EPA has established a RfD for manganese of 0.14 mg/kg/daywhich equates to approximately 10,000 µg/day for adults and 2,100 µg/day for a 15 kg child. Using themost recent data, we conclude that drinking two liters of water each day from the potable water wells likely would not result in excess manganese exposure.
There are very few studies regarding adverse effects in humans after oral exposure to vanadium. Humanvolunteers given 0.47 to 1.3 mg-vanadium per kilogram body weight as ammonium vanadyl tartrate for45 to 68 days had intestinal cramping and diarrhea. It could not be determined whether this effect wascaused by the vanadium . The same volunteers showed no hematological abnormalities (as measuredby white blood cell count, differential count, platelets, and reticulocytes), hepatic effects (no changes inoxaloacetic transferase, cholesterol, triglyceride, or phospholipid levels), or renal effects (normal bloodurea nitrogen levels and no changes in urinalysis for albumin or hemoglobin). A no observable adverseeffect level (NOAEL) of 1.3 mg-vanadium/kg-body weight for hepatic, hematologic, and renal effects wasidentified. No documentation of human health effects from ingestion of drinking water were located andno other significant health effects from oral exposure to vanadium have been found in humans .
The Agency for Toxic Substances and Disease Registry (ATSDR) has developed an intermediate-durationoral Minimal Risk Level (MRLi) for vanadium of 0.003 mg-vanadium/kg-body weight/day (mg/kg/day). The MRLi is based on a study in which rats were given selected concentrations (1, 5, 10, or 50 mg/L) ofvanadium (as sodium metavanadate) for three months . Serum cholesterol and glucose levels, liverfunction, organ weights, weight gain, and water consumption were unaffected at all exposure levels;however, the treated animals did show mild histological changes in kidneys, lungs, and spleen that becameprogressively more severe with increased dosages. ATSDR identified a No Observable Adverse EffectsLevel (NOAEL) of 5 mg/L (0.3 mg/kg/day). The MRLi of 0.003 mg/kg/day was derived by dividingthe NOAEL by an uncertainty factor of 100 (10 for extrapolation from animals to humans and 10 toaccount for human variability).
The maximum concentration of vanadium found in the groundwater was found in water from a residentialwell (50 µg/L). Although a child using this water, theoretically, slightly could exceed the MRL, theestimated dose would be over 400 times lower than the NOAEL (1.3 mg/kg/day) for actual effects observed in humans exposed to vanadium in drinking water for 45 to 60 days.
Eating or drinking benzene contaminated food or water can cause gastrointestinal irritation, dizziness, anemia, and suppression of the immune system. Based on an increased incidence of lymphoma and leukemia in people, EPA has classified benzene as a known human carcinogen. EPA used cancer risk data from human epidemiological studies of workers exposed by inhalation to derive risk factors associated with oral exposure to benzene. EPA has set the MCL of benzene in drinking water at 5 µg/L . The Farmers Co-op well contained a benzene level of 680 µg/L; however, water from this well was used for non-potable purposes in a restroom. Water from this well currently is treated prior to use.