PUBLIC HEALTH ASSESSMENT
STATE ROAD 114 GROUNDWATER PLUME
LEVELLAND, HOCKLEY COUNTY, TEXAS
The State Road 114 Groundwater Plume site consists of a contaminated groundwater plume in the Ogallala aquifer along the western boundary of the City of Levelland, Hockley County, Texas. Water wells along State Highway 114 (SH 114) and Farm to Market 1490 (FM 1490) have been affected, and additional water wells are in the migration path of the contaminated groundwater plume.
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 are not high enough to result in health problems. In the future, contaminants could migrate toward additional wells. Ongoing sampling has been initiated by the Texas Natural Resource Conservation Commission to track the migration of the groundwater plume.
The U.S. Environmental Protection Agency is working with state agencies and local representatives to develop a plan for treating the contaminated groundwater plume. The Texas Department of Health and the Agency for Toxic Substances and Disease Registry will evaluate additional well water data as they become available.
ATSDR PUBLIC HEALTH CONCLUSION CATEGORIES
| CATEGORY A. URGENT PUBLIC HEALTH HAZARD 1
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CATEGORY B. PUBLIC HEALTH HAZARD 1
Criteria: |
CATEGORY C. INDETERMINATE PUBLIC HEALTH HAZARD This category is used for sites in which "critical" data are insufficient with regard to extent of exposure and/or toxicologic properties at estimated exposure levels.
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CATEGORY D. NO APPARENT PUBLIC HEALTH HAZARD 1 This category is used for sites where human exposure to contaminated media may be occurring, may have occurred in the past, and/or may occur in the future, but the exposure is not expected to cause any adverse health effects. Criteria: |
CATEGORY E. NO PUBLIC HEALTH HAZARD This category is used for sites that, because of the absence of exposure, do NOT pose a public health hazard.
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The Agency for Toxic Substances and Disease Registry (ATSDR) was established under the mandate of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980. This act, also known as the "Superfund" law, authorized the U.S. Environmental Protection Agency (EPA) to conduct clean up activities at hazardous waste sites. EPA was directed to compile a list of sites considered hazardous to public health. This list is called the National Priorities List (NPL). The 1986 Superfund Amendments and Reauthorization Act (SARA) directed ATSDR to prepare a Public Health Assessment (PHA) for each NPL site. (Note: Appendix A provides a listing of abbreviations and acronyms used in this report.)
In conducting the PHA, three types of information are used: environmental data, community health concerns, and health outcome data. The environmental data are reviewed to determine whether people in the community might be exposed to hazardous materials from the NPL facility. If people are being exposed to these chemicals, ATSDR will determine whether the exposure is at levels which might cause harm. Community health concerns are collected to determine whether health concerns expressed by community members could be related to exposure to chemicals released from the NPL site. If citizens raise concerns about specific diseases in the community, health outcome data (information from state and local databases or health care providers) can be used to address the community concerns. Also, if ATSDR finds that harmful exposures have occurred, health outcome data can be used to determine if illnesses are occurring which could be associated with the hazardous chemicals released from the NPL site.
In accordance with the Interagency Cooperative Agreement between ATSDR and the Texas Department of Health (TDH), ATSDR and TDH have prepared this PHA for the State Road 114 Groundwater Plume site. This PHA presents conclusions about whether exposures are occurring, and whether a health threat is present. In some cases, it is possible to determine whether exposures occurred in the past; however, often a lack of appropriate historical data makes it difficult to quantify past exposures. If it is found that a threat to public health exists, recommendations are made to stop or reduce the threat to public health.
The State Road 114 Groundwater Plume site consists of a contaminated groundwater plume in the Ogallala aquifer along the western boundary of the City of Levelland, Hockley County, Texas (Figure 1) [1]. The plume extends west to east for approximately 1.5 miles along State Highway 114 (SH 114) from the former Motor Fuels Corporation property west of Evening Tower Road, to the City of Levelland municipal park (Figure 2). The plume is approximately one mile wide, bounded roughly by Ellis Road to the north and Houston Avenue to the south [1, 2]. Water wells along SH 114 and Farm to Market Road 1490 (FM 1490) have been affected and additional water wells are in the migration path of the contaminated groundwater plume.
In June 1990, the Texas Department of Health (TDH) first detected groundwater contamination in well water at the Farmer's Co-op Elevator Association. Benzene was measured at 77 micrograms per liter (µg/L) and 1,2-dichloroethane was measured at 11 µg/L. Subsequent sampling of this well by the Texas Water Commission (TWC) in 1991 and by the Texas Natural Resource Conservation Commission (TNRCC) in 1995 indicated that concentrations of benzene, 1,2-dichloroethane, and other contaminants in the water were increasing [3]. As a result, the use of water from this well was restricted.
Investigations conducted by the TNRCC and the U.S. Environmental Protection Agency (EPA) between 1997 and the present (2000) identified contamination in 28 area water wells (19 residential wells, five business wells, an irrigation well, and three City of Levelland municipal wells) [1, 2, 3, 4].
Several potential sources of the contaminated groundwater plume have been investigated by the TNRCC. Among them are the former Motor Fuels Corporation facility, the Farmers Co-op Elevator Association, and oil field service related businesses along the south side of SH 114 [2].
The Motor Fuels Corporation site was a former petroleum products refinery that operated from mid-1939 to 1954. The site consisted of approximately 64 acres. The refinery and aboveground storage tanks were demolished and removed and in 1958 the land was sold off in parcels [5]. Among the current owners of this property are the Farmer's Co-op Elevator Association, Edward's Transport, Inc., and Well-Co Oil Service, Inc. The TNRCC documented contamination in soil at the former Motor Fuels Corporation property and in off- site well water during investigations conducted in October 1995 and March 1997 [3].
At the request of the TNRCC, TDH completed several health consultations for the site [6,7,8, 9, 10]. The TNRCC notified individual well owners of the groundwater contamination and TDH provided written information about the contaminants of concern and how exposure could be minimized. The TNRCC and the EPA have temporarily addressed the hazard posed by the use of the contaminated well water by installing and maintaining groundwater filtration systems for these wells [1]. The wells continue to be sampled quarterly and maintenance of the wells' filtration systems is ongoing as EPA and TNRCC work to develop a plan to address the groundwater contamination.
The State Road 114 Groundwater Plume site was proposed to the National Priorities List of Superfund Sites on July 22, 1999, and was added to the National Priorities List on October 22, 1999 [11].
We (TDH) visited the State Road 114 Groundwater Plume site on November 19, 1999 [12] and met with the EPA Project Manager and representatives of the Farmer's Co-op both to brief them on the ATSDR public health assessment process and obtain current site information. We spent about one and one-half hours examining the area over the plume and the surrounding properties. We visited the Farmer's Elevator Co-op Association property, the neighborhood along FM 1490 where private water wells have been affected, the area around the nearest municipal water wells, and the former Motor Fuels Corporation property.
Some of the businesses along SH 114 were fenced, thus limiting access to the former Motor Fuels Corporation property. However, the former Motor Fuels Corporation property was not fenced and was accessible from SH 114 via the Edwards Transport property and from Evening Tower Road via the Farmer's Co-op Association property (Figure 2).
We saw a 900 by 900-foot playa basin on the northwest part of the former Motor Fuels property, five tarry pits east and south of the playa, and two long excavated areas near the pits (Figure 3). The surface of the playa was dry and crusted over. Dark liquid oozed from the surface of the playa basin as we walked over the surface [12]. We did not see any standing water; however, the two long excavated areas and the tarry pits contained dark-stained soil and liquid. There was tall vegetation surrounding the dry playa basin, but the plants growing around the tarry pits appeared to be stunted.
We did not see any bodies of water (ponds, stock tanks, etc.) or residences on the former Motor Fuels property, but we did see what appeared to be an injection well, south of the playa, on the property.
The area around the site is flat, and there were agricultural crops of cotton and milo, oil wells, and brine injection wells throughout the area [12].
The closest occupied household is north of SH 114 across from the Farmer's Co-op Association. We saw a daycare facility along the north side of SH 114 in the path of the contaminated groundwater plume (Figure 2). There were horses on some of the properties along FM 1490.
Closed City Water Well #18 is near the intersection of SH 114 and FM 1490, and there is an oil well approximately 100 yards south of the city well [12].
The City of Levelland has a population of 13,986, and the population of Hockley County is estimated to be 23,374 [13, 14]. Approximately 320 people live within one mile of the State Road 114 Groundwater Plume site and 37 of them are age 6 years or younger. Two hundred (200) people work in the vicinity of the site [13, 15]. Currently there are 11 full-time workers at the Farmer's Co-op [1, 15]. Within the area of the contaminated groundwater plume, private wells serve 60 people, and the public water supply wells in the migration path of the plume serve 3,007 people [2].
ENVIRONMENTAL CONTAMINATION / PATHWAYS ANALYSIS / PUBLIC HEALTH IMPLICATIONS
Exposure to, or contact with chemical contaminants drives the ATSDR public health assessment process. The release or disposal of chemical contaminants into the environment does not always result in exposure or contact. Chemicals have the potential to cause adverse health effects only if people 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 a substance 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 with contaminants depend on the toxicologic properties of the contaminants, how much of the contaminant to which the individual is exposed, how often and/or how long exposure is allowed to 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 the individual absorbs, distributes, metabolizes, and excretes the contaminant. These factors and characteristics influence 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 compared contaminant concentrations to health assessment comparison (HAC) values. HAC values are media-specific contaminant concentrations that are used to screen contaminants for further evaluation. Non-cancer HAC values are called environmental media evaluation guides (EMEGs) or reference dose media evaluation guides (RMEGs) and are respectively based on ATSDR's minimal risk levels (MRLs) or EPA's reference doses (RfDs). MRLs and RfDs are estimates of a daily human exposure to a contaminant that is unlikely to cause adverse non-cancer health effects. Cancer risk evaluation guides (CREGs) are based on EPA's chemical specific cancer slope factors and an estimated excess lifetime cancer risk of one-in-one-million persons exposed for a lifetime. We used standard assumptions to calculate appropriate HAC values [16].
In some instances, we compare contaminant concentrations in water to EPA's maximum contaminant levels (MCLs). MCLs are chemical-specific maximum concentrations allowed in water delivered to the users of a public water system; they are considered protective of public health over a lifetime (70 years) of exposure at an ingestion rate of two liters per day. The setting of MCLs may also be influenced by available technology and economic feasibility. Although MCLs only apply to public water supply systems, we often use them to help assess the public health implications of contaminants found in water from other sources.
While exceeding a HAC value does not necessarily mean that a contaminant represents a public health threat, it does suggest that the contaminant warrants further consideration. The public health significance of contaminants that exceed HAC values may be assessed by reviewing and integrating relevant toxicological information with plausible exposure scenarios. Estimated exposures may be compared to reported No Observable and Lowest Observable Adverse Effects Levels (NOAELs and LOAELs) and to known effect levels in humans, when available. Contaminants where concentrations were below ATSDR's HAC values were excluded from further consideration.
The TNRCC collected soil samples during the Expanded Site Investigation for the Motor Fuels Corporation site March 10-12, 1997 [3]. Soil samples were analyzed for volatile organic compounds, semivolatile organic compounds, pesticides, PCBs, and metals [3]. Since groundwater contamination had been identified in the water well at the Farmer's Co-op, which is on the former Motor Fuels Corporation property, in August 1998 the TNRCC sampled additional water wells in the vicinity of this property [2]. Samples were analyzed for volatile organic compounds, semivolatile organic compounds, and metals [2]. Water wells were resampled in July and August of 1999. The public health significance of the above mentioned sampling events was addressed in previous health consultations prepared by TDH for ATSDR [6, 7, 8, 9, 10].
Between January and March 2000 by Daniel B. Stephens & Associates, Inc. (DBS&A), a contractor for the TNRCC collected water samples from residential, business, and municipal wells [17, 18]. These samples were analyzed for volatile organic compounds and metals [17, 18]. The public health significance of the results from these samples is addressed in this public health assessment. In reviewing these data, we relied on the information provided in the referenced documents and assumed that adequate Quality Assurance and Quality Control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The conclusions in this public health assessment are valid only if the referenced information is valid and complete.
To determine whether people in the community could be exposed to (or come into contact with) contaminants from the site, we evaluated the possible pathways for exposure to contaminants at the State Road 114 Groundwater Plume National Priorities List 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, potentially exposed population. Exposure pathways 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 all five elements in the pathway are present and exposure has occurred, is occurring, or will plausibly occur in the future. A potential pathway is missing at least one of the five elements but possibly may be complete in the future as more data become available or site conditions change. Eliminated pathways are missing one or more of the five elements and will never be complete. The completed and/or potential exposure pathways considered in our evaluation of this site are summarized in Table 1.
Table 1. Exposure Pathway Evaluation-State Road 114 Groundwater Plume National Priorities List Site
| PATHWAY NAME |
CONTAMINANTS OF CONCERN | EXPOSURE PATHWAY SELEMENTS | TIME | COMMENTS | ||||
| SOURCE | ENVIRONMENTAL MEDIA |
POINT OF EXPOSURE |
ROUTE OF EXPOSURE |
EXPOSED POPULATION |
||||
| Groundwater | 1,2-Dichloroethane Arsenic Manganese Vanadium Benzene |
Unknown source, possibly tarry pits and playa basin that received discharge from the former Motor Fuels Corp. site |
Groundwater |
Residences and businesses using water wells along FM 1490 and SH 114 | Ingestion Inhalation Dermal contact | Individuals using contaminated wells along FM 1490 and SH 114 | Past | There is sufficient evidence indicating that prior to
the installation of individual treatment systems, approximately 60 people
used water from the contaminated groundwater plume. In the past the contaminants
in the groundwater presented a public health hazard.
|
| None | Present | TNRCC has installed individual treatment systems to remove contaminants from the water prior to use. Exposure to contaminants in groundwater currently poses no public health hazard at this time. | ||||||
| 1,2-Dichloroethane Arsenic Manganese Vanadium Benzene |
Future | Future use of groundwater wells west of Levelland, prior to treatment, could pose a public health hazard if water is not treated and/or additional wells become contaminated. | ||||||
| Soil | Petroleum constituents | Motor Fuels Corp. operations |
Soil |
Playa basin, excavated pits, tarry pits on Motor Fuels site | Incidental ingestion Inhalation Dermal contact |
Trespassers Former workers |
Past Present Future |
Because of the low likelihood of exposure we have classified this pathway as posing no apparent public health hazard. |
| Air | Volatile petroleum constituents |
Motor Fuels Corp. operations |
Air |
Motor Fuels Corp. site and vicinity | Inhalation | Workers Nearby residents |
Past | Because of the lack of ambient air data during the time that the MFC facility was operating, the air pathway is an indeterminate public health hazard. |
| Present Future |
Because the MFC is no longer operating this exposure pathway is eliminated. | |||||||
Evaluation of Possible Groundwater Exposure Pathways
The State Road 114 Groundwater Plume site is located over the Ogallala aquifer which provides approximately 20 to 30 percent of the City of Levelland's drinking water and serves as the principal source of drinking water for numerous individual well owners in Hockley County [2,19]. The Ogallala consists of the saturated sediments of the Ogallala Formation and is generally under water table conditions (unconfined). In the area of the contaminated groundwater plume the Ogallala aquifer ranges in thickness from 50 to 300 feet and the depth to groundwater ranges from 120 to 150 feet below ground surface [2, 4]. The water in the aquifer flows toward the east (Figure 2) [2,19]. Area water wells generally are screened between 100 and 260 feet below ground surface [2]. High chlorides and sulfates are commonly found in the alkaline playa basins of Hockley County and affect area water quality. Water quality of the Ogallala ranges from good to slightly salty.
Within four miles of the contaminated groundwater plume there are 60 private wells, 13 business wells, 17 municipal wells, and 47 irrigation wells [2, 3]. Between January 21, 2000 and March 4, 2000, a contractor for the TNRCC sampled 22 residential water wells, nine business wells, and four City of Levelland municipal water supply wells (Figure 2). Samples were analyzed for volatile organic compounds and total metals. Constituents exceeding HAC values are shown in Appendix C; Table 2.
Water from privately owned wells along the length of FM 1490 between Ellis Road and SH 114 contained 1,2-dichloroethane, arsenic, manganese, and vanadium at concentrations exceeding their respective HAC values [18]. Disinfection by-products (bromodichloromethane, bromoform, chloroform, and dibromochloromethane) were detected in one of the wells but were below the maximum concentration level for total trihalomethanes of 100 µg/L (Table 2). Individual water treatment systems designed to remove the contaminants of concern from the water prior to household use have been installed on each well in which contaminants were measured at concentrations of potential public health concern. Prior to the installation of the treatment systems, people using water from these wells could have been exposed to the contaminants of concern through ingestion (1,2-dichloroethane, arsenic, manganese, and vanadium), inhalation (1,2-dichloroethane), and/or dermal contact (1,2-dichloroethane). The public health significance of possible past exposures to site contaminants is addressed in Appendix-D.
Currently, the contaminants measured in water from the residential wells pose no apparent public health hazard either because the wells are on individual treatment systems or exposure to the contaminants of concern in wells without treatment systems would not be expected cause adverse effects. In the future the migration of contaminants in the groundwater could affect additional wells.
Benzene has been detected in water from the well at the Farmer's Co-op at concentrations more than one hundred times higher than EPA's maximum contaminant level of 5 µg/L and over 500 times higher than the CREG value for benzene. Benzene was detected in water from one other business well at a concentration of 2 µg/L; however, the results were questionable since benzene was detected in the sample collected after the water was treated but was not in the sample collected directly from the well [18]. Benzene has not been detected in any of the other wells sampled. Other contaminants (1,2-dichloroethane, arsenic, manganese, and vanadium) were detected at levels at or above their respective HAC values in business wells (Table 2). Individual water treatment systems designed to remove the contaminants of concern from the water prior to use have been installed on each well in which contaminants were measured at concentrations of potential public health concern. Prior to the installation of the treatment systems, individuals using water from these wells could have been exposed to site contaminants through ingestion (benzene, 1,2-dichloroethane, arsenic, manganese, and vanadium), inhalation (benzene, 1,2-dichloroethane), and/or dermal contact (benzene, 1,2-dichloroethane). Currently, the contaminants measured in water from the business wells poses no apparent public health hazard either because the wells are on individual treatment systems or exposure to the contaminants of concern in wells without treatment systems would not be expected cause adverse effects. In the future the migration of contaminants in the groundwater could affect additional wells. The public health significance of possible past exposures to site contaminants is addressed in Appendix-D.
Low concentrations of volatile organic compounds associated with chlorination by-products were measured in City Well #21 but were below the maximum concentration level for total trihalomethanes of 100 µg/L (Table 2). Lead was detected in one sample from City Well #21 at a concentration of 37 µg/L. Manganese was measured at concentrations above its child-based HAC value (500 µg/L) in water from City Wells #15 (1,390 µg/L) and #23 (1,190 µg/L) [18]. Vanadium was measured in water from City Wells #10, #15, and #23 at concentrations at or above its HAC value [18]. Since water from the municipal wells is blended with treated water from Lake Meredith at a ratio of approximately one-third municipal well water to two-thirds treated lake water, the actual concentration of the contaminants delivered to the end users of the municipal water system is much lower than those measured at any one individual well. According to available records, the City of Levelland drinking water supply meets all the standards of the Safe Drinking Water Act. At the present time, we do not consider this to be a significant exposure pathway and have classified it as posing no apparent public health hazard.
Evaluation of Possible Soil Exposure Pathways
In the past, volatile and semi-volatile organic compounds were detected in soil from the Motor Fuels Corporation property at three depths (four, six, and eight feet below ground surface) [3]. The playa basin reportedly received wastewater from the former petroleum refinery. While it is not likely that volatile organic compounds remain in the surface soil, it is possible that other contaminants still may remain in the surface soils. While this pathway could be considered to be an indeterminate public health hazard because of the general lack of surface soil data, the property is somewhat remote. In our professional judgement, the likelihood that people are receiving significant exposures is low. We have therefore classified this pathway as posing no apparent public health hazard.
Evaluation of Possible Air Exposure Pathways
Due to discharges to the playa basin, spills, and other site-related activities, volatilization of petroleum constituents into the air may have occurred during the time that the Motor Fuels Corporation facility was operating. Due to a lack of air sampling data during the time that the facility was operating, we were not able to evaluate this pathway; therefore, past exposure to air in the vicinity of the Motor Fuels Corporation facility is an indeterminate public health hazard. Currently, the Motor Fuels Corporation facility is not operating. Thus, at the present time we do not consider this to be a significant exposure pathway and have eliminated it from further consideration.
CHILD HEALTH INITIATIVE/HEALTH OUTCOME DATA/ COMMUNITY HEALTH CONCERNS
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 important, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care.
ATSDR evaluated the likelihood for children living in the vicinity of the State Road 114 Groundwater Plume site to be exposed to 1,2-dichloroethane and other contaminants at levels of health concern. In the past children may have been exposed to contaminants in the groundwater although data were insufficient to evaluate possible past exposures. Children currently are not exposed to contaminants in the groundwater since individual treatment systems have been installed on each of the affected wells.
The private well at the daycare (Figure 2) had no measurable concentrations of volatile organic compounds. The metal vanadium was measured at 30 µg/L and all other metals were below detection. A child (15kg) drinking water with this concentration of vanadium would not be likely to experience any adverse health effects [10].
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. Examples of health outcome databases are tumor 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.
To collect community health concerns related to the State Road 114 Groundwater Plume site, we contacted several different agencies and individuals including the Texas Department of Health Region 1, the Texas Natural Resource Conservation Commission, and the U.S. EPA Region 6. In addition, we contacted the City Manager for the City of Levelland and representatives from the Farmer's Co-op. We received the following concerns:
Just as in people, many factors will determine whether harmful health effects will occur and what the type and severity of those health effects will be. These factors include the amount and type of contaminant, the dose, the duration and route of exposure and individual characteristics such as age and overall state of health. Generally, the concentrations of 1,2-dichloroethane and vanadium in the groundwater are low; however, we did not find any specific literature with respect to the effects of these contaminants on horses.
We were unable to find any specific toxicological studies evaluating the effects of exposure to the contaminants of concern on the thyroid; however, thyroid disorders are reportedly very common. According to the Thyroid Foundation of America, 13 million people have some form of thyroid dysfunction. Thyroid disease is up to eight times more common in women than in men. There seems to be a genetic component to thyroid disease although other factors such as age and stress also are related. There are some contaminants such as perchlorate which are known to affect the thyroid. To our knowledge, perchlorates have not been associated with this site.
We are not aware of any associations between the contaminants of concern and hysterectomies.
An analysis of incidence and mortality data by the Texas Department of Health Cancer Registry Division did not show an excess of these cancers in Hockley County.
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