BALLARD SAND PITS
(a/k/a BRINE SERVICE COMPANY, INCORPORATED CALALLEN PIT)
CORPUS CHRISTI (CALALLEN AREA), NUECES COUNTY, TEXAS
The Texas Department of Health Environmental Epidemiology and Toxicology Division (TDH(1)),under a cooperative agreement with the Agency for Toxic Substances and Disease Registry(ATSDR), reviewed environmental data collected by the Railroad Commission of Texas (RCT)and evaluated the potential for contamination from the waste pits at the Ballard Sand Pits site topose a health hazard to the people living nearby. This health consultation was initiated to addressthe community's concern that flooding may have spread contamination from the waste pits intoresidential yards and water wells. In addition, TDH and Corpus Christi Nueces County HealthDistrict (CCNCHD) surveyed the community members living in subdivisions nearest the wastepits (Riverside, Twin Lakes, and Wade Riverside subdivisions) to document their healthconcerns.
Based on plausible exposure scenarios and using the maximum contaminant concentrations measured in the waste pits, TDH concluded that the exposure to material from the waste pits poses no apparent public health hazard to either workers or trespassers. Under some theoretical conditions, however, the contaminants in the waste pits could pose a health hazard to small children (22 pounds) if they were to regularly trespass on the site. Because it is unlikely that a child of this size would frequent the site, TDH concluded that exposure is unlikely and that the material in the waste pits poses no apparent public health hazard to small children.
The arsenic levels in the residential soil are within those normally found in soil from this part of the United States. Based on conservative exposure estimates, we would not expect the arsenic in the soil to pose a public health hazard. Levels of arsenic and barium, although detected in residential drinking water wells, were below current drinking water standards.
The survey conducted by TDH and CCNCHD documents the community health concerns ofpeople living in the Riverside, Twin Lakes, and Wade Riverside subdivisions. The most commonhealth concerns reported were related to the digestive system. Due to the low survey responserate (40 percent) and small numbers of respondents (160), associations between health concernsexpressed by the community and chemicals found in the waste pits could not be made.
The Ballard Sand Pits property is an active sand and gravel quarry in an unincorporated part ofNueces County off State Highway 73. The property contains two pits, an "East Pit" and a "West Pit,"that may have received drilling mud and possibly refinery waste . The East Pit is immediately tothe west of homes on Nimrod Circle in the Twin Lakes Subdivision (Appendix B; Figure 1). Thereare two other neighborhoods in the vicinity of the pits, the Riverside subdivision to the north and theWade Riverside subdivision to the south (Appendix B; Figure 1). The entire area, consisting of theBallard Sand Pits property and the adjacent residential neighborhoods, is within the 100-yearfloodplain of the Nueces River . According to community members, their homes have floodedfour times between 2001 and 2002.
In the summer and fall of 2002 heavy rains caused the Nueces River to flow over its banks; someof the residential water wells were under water . In October 2002, to test whether the floodingaffected the water quality of the wells near the waste pits, the Railroad Commission of Texas (RCT)tested water from four of the residential wells . The RCT tested the water for total petroleumhydrocarbons (TPH), volatile organic compounds (VOCs), semi-volatile organic compounds(SVOCs), polychlorinated biphenyls (PCBs), pesticides, herbicides, metals, chlorides, coliformbacteria, and total dissolved solids (TDS).
After the floodwaters subsided, the RCT collected additional samples to characterize the contentsof the waste pits to determine whether material from the pits had been transported to residential soil,and to further determine whether contaminants from the pits had been transported into residentialwater wells [6,7]. Material from the pits, residential surface soil, and water from the wells were tested for TPH, VOCs, SVOCs, PCBs, and metals.
In January 2003, at the request of State Representative Jaime Capelo, TDH staff attended acommunity meeting with the RCT, the Texas Commission on Environmental Quality (TCEQ),the CCNCHD, the County Engineer, and an aide to State Representative Juan Hinojosa.Approximately 65 households were invited to the neighborhood meeting. Community membersvoiced concerns that their health problems might be due to chemicals from the waste pits. Manycommunity members expressed concerns about the flooding of their homes. Some communitymembers were concerned that the sand being mined from the property was contaminated.
Following this meeting, at the request of the State Representative's office, TDH and CCNCHDdeveloped a survey tool to document and enumerate the community's health concerns. Thesurvey was delivered to all of the 135 homes located in the subdivisions nearest the waste pits(Appendix B; Figure 1). Fifty-four household surveys (40 percent) were completed and returnedto TDH. Because the survey was specifically designed to document community health concernsand because the response rate of the community was low, no associations between thedocumented health concerns and the chemicals found in the waste pits can or should be made.Fifty-eight percent of the respondents reported their overall health to be Poor or Fair; 42% of therespondents reported their overall health as Very Good or Good.
The survey respondents were asked to list all health concerns (both symptoms and diagnosedillnesses) for each person identified in the survey. Approximately 43% of the 160 people indicatedat least one health concern, while 56.9% did not report a single health concern. The most commonhealth concerns reported were related to the digestive system (Appendix C; Table 1).
There were statistically significant differences in the percent of people reporting digestive systemrelated health concerns by the household's water source. Thirty households identified a private wellas the source of the home's tap water. Fourteen households use a public water supply source; sixidentified the Nueces River as the source for water. Approximately 80% of those returning thesurvey said they drank bottled water instead of the tap water.
Conclusions based on these results must be limited due to the design of the survey, the low responserate, the high number of questions left blank by the participants, and the inability to account forpotential confounding risk factors. The cause of the differences cannot be determined from thissurvey as it was designed only to collect and document the health concerns, not to determine their causes.
The environmental sampling data used in this report includes data collected by the RCT in 2002 and2003 [1-7]. In preparing this report TDH/ATSDR relied on the information provided in thereferenced documents and assumed adequate quality assurance/quality control (QA/QC) procedureswere followed with regard to data collection, chain-of-custody, laboratory procedures, and datareporting.
In considering the potential public health significance of these sample results we recognize that someof the data used in this assessment were not necessarily collected with the goal of assessingexposure. For example, the waste pit samples were collected below the ground surface and for thepurpose of characterizing the contents of the pits. Exactly who may come into contact with thecontaminated waste in the pits, residential soil, or residential well water, how often they may comeinto contact with these media, and how much of the media they may come into contact with is notknown. As such, the exposure estimates used in this consultation are theoretical and in many casesworse case scenarios. They should not be taken to apply to any specific individual.
To assess the potential health risks associated with the contaminants found in the various media(waste pits, residential yard soil, and residential well water), TDH compared each contaminantdetected with its health-based assessment comparison (HAC) values for non-cancer and cancerendpoints. HAC values are guidelines that specify levels of chemicals in specific environmentalmedia (soil, air, and water) that are considered safe for human contact.
TDH used either the Agency for Toxic Substances and Disease Registry's (ATSDR's) minimal risklevels (MRLs) or the U.S. Environmental Protection Agency's (EPA's) reference doses (RfDs) toderive the non-cancer HAC values. MRLs and RfDs are based on the assumption that there is anidentifiable exposure threshold (both for the individual and for populations) below which there areno observed adverse effects. Thus, MRLs and RfDs are estimates of daily exposures to contaminantsthat are unlikely to cause adverse non-cancer health effects even if exposure occurs for a lifetime.The cancer risk comparison values that TDH used in this consultation are based on EPA's chemical-specific cancer slope factors (CSFs), an estimated excess lifetime risk of one cancer in one-million(1 x 10-6) exposed people, and an exposure period of 70 years. TDH used standard assumptions forbody weight (10 kilograms, child; 70 kilograms, adult), soil ingestion (200 milligrams per day, child;100 milligrams per day, adult trespasser; 50 milligrams per day, adult worker), and water ingestion(1 liter per day, child; 2 liters per day, adult) to calculate the HAC values. Since many of theassumptions used to calculate HAC values are conservative with respect to protecting public health,exceeding a HAC value does not necessarily mean that adverse health effects will occur. However,exceeding a HAC value does suggest that potential site-specific exposure to the contaminantwarrants further consideration.
In some instances, we compare contaminant concentrations in water to EPA's maximumcontaminant levels (MCLs). MCLs are chemical-specific maximum concentrations allowed in waterdelivered to the users of a public water system; they are considered protective of public health overa lifetime (70 years) of exposure at an ingestion rate of 2 liters per day. In addition to potential healtheffects, the setting of MCLs also may be influenced by available technology and economicfeasibility. Although MCLs are only enforceable on public water systems, we often use them as aguide to help assess the potential public health implications of contaminants found in water fromother sources.
Contaminants in Material from the Waste Pits
A total of twelve (12) samples, eight (8) from the East Pit and four (4) from the West Pit, werecollected at various depths below the ground surface . TPH was detected in both pits and wasgenerally higher in samples from the West pit. The following individual constituents exceeded theirrespective health-based screening values: benzene, toluene, benzo[a]pyrene, naphthalene, PCBs,arsenic, chromium, and lead (Appendix C; Table 2).
Contaminants in Soil from Residential Yards
Surface soil samples were collected from nineteen (19) residential yards. Arsenic and other metalswere the only contaminants measured at levels above their respective detection limits. Arsenic wasthe only constituent found in the soil at concentrations above one of its health-based screening values(0.5 milligram per kilogram [mg/kg]). The levels of arsenic measured (0.71-3.79 mg/kg) werecomparable to background soil levels reported for the Western United States (range less than [<] 0.1-97 milligrams per kilogram [mg/kg] [; average 7.0 mg/kg) . One sample of oil-coated vegetationcontained TPH (C6-C35) at a concentration of 136,000 mg/kg. TPH was not detected in any of theresidential soil samples.
Contaminants in Water from Residential Wells
In October 2002, arsenic was detected in water from four residential wells near the pits atconcentrations that ranged from 31 to 39 micrograms per liter (µg/L) [6,7]. In December 2002, afterthe floodwaters had subsided, water from 16 residential wells was collected. Arsenic (7.28 µg/L-45.2µg/L) and barium (27.9 µg/L-861 µg/L) were the only constituents detected at levels exceeding theirrespective health-based screening values.
The Waste Pits
Currently, access to the sand quarry property is limited to those people who work at the site;however, because the site is not completely fenced, trespassers (including children and adolescents)could gain access to contaminated areas. Thus, it is possible that workers and/or trespassers couldbe exposed to the material in the waste pits. Using the maximum contaminant concentrations foundin the pits we conservatively estimate that exposure to this material (through incidental ingestion)could result in risk estimates for workers (50 mg/day) and trespassers (100 mg/day) that qualitativelyindicate no apparent increased excess lifetime risk for developing cancer (Figures 2 and 3). Therange of risk estimates presented for workers is based on exposures occurring 1 to5 days per weekfor 5 to 30 years (Figure 2). Similarly the range of risk estimates presented for trespassers is basedon exposures occurring 1 to 5 days per week for 1 to 9 years (Figure 3). Thus, while exposures arepossible, it is unlikely that they would result in adverse cancer health effects. Based on the availableinformation we conclude that the material in the pits poses no apparent public health hazard, eitherto workers or trespassers. Several of the contaminants found in the East and West pits also exceededtheir respective non-cancer screening values for children. These include toluene, naphthalene, PCBs,arsenic, chromium, and lead. These screening values are based on a 10-kilogram child(approximately 22 pounds) regularly ingesting 200 mg of the waste material every day. As it isunlikely that a child of this size would regularly frequent the site unsupervised, the exposureassumptions used to calculate these screening values, as applied to this site, are conservative.
Nearby residents could be exposed to material from the waste pits if it was transported to off-site soilor to residential wells during flood events. TPH, which was found in both of the pits, was not foundin the residential soil or residential water wells. Arsenic, a naturally occurring element in the earth'scrust, was detected in residential soil at concentrations consistent with normal backgroundconcentrations. Arsenic and barium both were detected in residential well water at concentrationsabove their respective screening values. Arsenic is a naturally occurring element in the earth's crustand the concentrations found in the soil were consistent with normal background concentrations.Qualitatively, chronic exposure to the concentrations of arsenic in the soil would result in noapparent increased lifetime risk for developing cancer. This estimate is conservative with respect toprotecting public health as it is based on a person ingesting 200 mg of soil everyday for 70 years.
The highest concentration of arsenic found in the well water (45.2 µg/L), is actually below thecurrent maximum contaminant level for this contaminant (50 µg/L); however, it is above the newMCL (10 µg/L) that will go into effect in 2006. The concentrations of arsenic in many of the wellsalso exceed both the non-cancer and cancer screening values. The most likely route of exposure tothese contaminants in the water is through ingestion, either by drinking it in beverages or by cookingwith it.
The potential effects of ingesting arsenic in drinking water are highly dependent on the dose (howmuch is ingested). The most common effects include gastrointestinal irritation, decreased productionof red and white blood cells, abnormal heart function, blood vessel damage, impaired nerve functioncausing a "pins and needles" sensation in the hands and feet, and a group of skin diseases, includinghyperkeratosis. Most of the non-cancer effects begin to occur at similar oral exposure levels.Ingestion of water with 300 micrograms per liter to 30,000 micrograms per liter of arsenic can causestomach and intestinal irritation. The levels observed in this area (7.28-45.2 µg/L) are orders ofmagnitude lower than the levels normally associated with these types of effects. The minimal doseat which these effects usually are observed in humans after chronic ingestion of arsenic ranges from12 to 100 micrograms of arsenic per kilogram of body weight per day (µg/kg/day). Based on themaximum concentration of arsenic measured in the water a child (10 kg) would have to drinkbetween 3 and 22 liters of water per day to receive such a dose (Appendix C; Table 3). A 70 kg adultwould have to drink between 19 and 155 liters of water per day to receive such a dose. Children andadults typically drink 1 and 2 liters per day, respectively.
Although there are no scientific reports that suggest arsenic can injure pregnant women or theirfetuses, studies of animals show that doses large enough to cause illness in pregnant females alsomay cause low birth weight, fetal malformations, or fetal death. One of the most characteristic effectsof long-term oral exposure to inorganic arsenic is a pattern of skin changes that includes a darkeningof the skin and formation of hyperkeratotic warts or corns on the palms, soles, and torso. Currentlythis end-point is considered the most appropriate basis for establishing a chronic oral Minimal RiskLevel (MRL) or Reference Dose (RfD). However, other end-points (liver injury, vascular disease,and neurological effects) also appear to have similar thresholds .
In one study of a very large population, Tseng (1968) found no adverse effects in any person withan average total daily intake of inorganic arsenic (water plus food) of 0.0008 mg/kg/day . Thisstudy has served as the basis for both ATSDR's MRL and EPA's RfD, both of which are 0.0003mg/kg/day . Both the RfD and the MRL were derived by dividing the 0.0008 mg/kg/day noobserved adverse effects level (NOAEL)(2) by an uncertainty factor of three (3) to account for boththe lack of data on reproductive toxicity and to account for some uncertainty as to whether theNOAEL accounts for all sensitive individuals. The lowest dose, associated with the epidemiologicstudies, at which adverse effects were observed, was 0.014 mg/kg/day.
Based on the concentrations measured in some of the wells from these residences children could be exposed to arsenic at doses up to four times the no observed adverse effects level. Adults could be exposed to arsenic at doses up to two times the no observed adverse effects level. Neither children nor adults would be likely to receive doses approaching those at which adverse effects have been observed. With respect to non-cancer health effects we would consider the levels found in some of these wells to be slightly elevated; however, the likelihood of actually observing adverse effects is low.
EPA also classifies arsenic as a known human carcinogen based on sufficient evidence from human data. An increase in lung cancer mortality was observed in multiple human populations exposed primarily through inhalation. Also, increased mortality from multiple internal organ cancers (liver, kidney, lung, and bladder) and an increased incidence of skin cancer (non-malignant) were observed in populations consuming water high in inorganic arsenic . We Used EPA's cancer slope factor (CSF) for arsenic to estimate the potential increased lifetime cancer risks associated with exposure to arsenic in the water from each of the wells. For people who drink 2 liters of water per day, 350 days per year, for 30 years, there may be a low increased lifetime risk for cancer (Appendix C; Table 4).
The maximum concentration of barium detected in well water (861 µg/L) exceeded the non-cancer screening value for children (700 µg/L). This screening value, derived from EPA's RfD for barium of 0.07 mg/kg/day, is based on hypertension as the health endpoint of concern and a weight-of-evidence approach supported by the finding of hypertensive effects in humans who ingested acutely high doses of barium compounds, in workers who inhaled dusts of barium ores, in animals given barium intravenously, and in rats exposed to barium in drinking water while on restricted diets [13, 14]. Lower dose human studies did not report any significant effects either on blood pressure or kidney function but did identify a NOAEL of 0.21 mg-barium/kg/day. An uncertainty factor of 3 was used to derive the RfD to account for some database differences and potential differences between adults and children.
Based on the concentrations measured in the wells from these residences it is unlikely that either children or adults would be exposed to barium at doses that would result in statistically or biologically significant increases in the frequency or severity of adverse effects. The concentrations of barium measured in these wells also are substantially below the MCL that EPA has promulgated for this contaminant (2,000 µg/L).
Other Constituents Measured in the Wells
Fecal coliform bacteria were not detected in any of the water wells; however, the levels of chlorides (550-2,250 milligrams per liter [mg/L]) and Total Dissolved Solids (1,540-2,930 mg/L) indicate that well water in the area is slightly saline.
TDH and ATSDR recognize that the unique vulnerabilities of infants and children demand specialemphasis. Children are at greater risk than adults from certain kinds of exposures to hazardoussubstances emitted from waste sites and emergency events. Children are more likely to be exposedbecause they play outdoors and often bring food into contaminated areas. They are shorter thanadults and breathe dust, soil, and heavy vapors that are close to the ground. Children are smaller thanadults, resulting in higher doses of chemical exposure per unit of body weight. The developing bodysystems of children can sustain permanent damage if toxic exposures occur during critical growthstages. Consequently, children who drink water contaminated with toxic substances may be atgreater risk for toxic effects than adults who consume the same water. Most importantly, childrendepend completely on adults for risk identification and management decisions, housing decisions,and access to medical care.
In an effort to account for children's unique vulnerabilities, TDH/ATSDR considered the potentialexposure to contaminants that children might receive from contact with waste material, residential soil, and well water.
Based on available information, TDH/ATSDR concluded that:
- The contaminants in the waste pits pose no apparent health hazard to workers or trespassersat the site. Under some theoretical conditions the contaminants could pose a health hazardto small children if they were to regularly come in contact with (play) in the waste pitmaterial. However, because this site is an active quarry, a child of this size is not likely tobe left unattended there; therefore, this exposure situation is not likely to occur.
- Arsenic was the only contaminant detected in residential soil at levels that are above ahealth-based screening value; however, arsenic is a natural element in the earth's crust andthe levels found were well within those normally found in soil from this part of the UnitedStates. Based on conservative exposure estimates we would not expect the arsenic in theresidential soil to pose a public health hazard.
- Other than constituents that contribute to the salinity and aesthetic quality of the water,arsenic and barium were the only contaminants found at levels above their respective health-based screening values. Neither was detected above its current MCL, indicating that therisks that people would incur from exposure to these contaminants in the well water wouldbe the similar to the risks currently deemed acceptable for any public drinking water system.It is important to note that the MCL for arsenic will be lowered to 10µg/L in 2006; thearsenic concentrations measured in 15 of the wells exceed this new standard. While it isunlikely that either children or adults would be exposed to arsenic or barium at doses thatwould result in statistically or biologically significant increases in the frequency or severityof adverse non-cancer effects, the margin of safety above the respective NOAELs is small,particularly for small children. Additionally, we estimate that chronic exposure to the levelsof arsenic in this water could result in a low increased excess lifetime risk for developingcancer.
- Based on the data provided at the time this report was initiated, we could not determine withany degree of certainty the source of the arsenic found in the wells. Arsenic is a naturallyoccurring element and is commonly found in some groundwater. The data did not indicatethe presence of other waste pit constituents in either the well water or the residential soil.
- The RCT sampled residential drinking water wells and provided the sampling results tothe well owners.
- The RCT sampled residential yards that were most likely to be affected by overflow fromthe waste pits during the floods and provided the test results to the occupants of thehouseholds.
- The TDH and CCNCHD surveyed residents of Riverside, Wade Riverside, and TwinLakes subdivisions to gather their health concerns.
- The TCEQ tested sand used for the beach reconstruction project for metals and found noproblems.
- The TCEQ put in six shallow groundwater monitoring wells in and near the waste pitsand sampled them for site contaminants.
- Continue to limit site access to site workers and consider fencing and/or posting warningsigns around the East and West waste pits.
- Individual well owners should consider connecting to an approved potable drinking watersource.
- The flooding issue should be addressed by the appropriate entities.
- The TDH plans to provide this report and survey results to the community andappropriate agencies.
- The TCEQ plans to evaluate monitoring well sampling data to determine appropriateactions.
Report Prepared by
Susan L. Prosperie, MS, RS
Environmental Epidemiology and Toxicology Division
Shari Shanklin, MPH
Environmental Epidemiology and Toxicology Division
John F. Villanacci, PhD
Environmental Epidemiology and Toxicology Division
ATSDR Regional Representative
George Pettigrew, PE
Senior Regional Representative
ATSDR Region 6
Robert Knowles, MS, REHS
Environmental Health Scientist
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
State Programs Section
- HBC Terracon. Ballard Sand Pits Assessment. Prepared for the Railroad Commission ofTexas. March 18, 2003.
- Federal Emergency Management Agency. National Flood Insurance Program. FloodInsurance Rate Map. Nueces County, Texas. Unincorporated areas. Panel 68 of 705. ZoneA9. September 27, 1972.
- Railroad Commission of Texas. Email to Susan Prosperie (TDH) from Heidi Bojes, RCTToxicologist concerning Ballard Pits sampling. September 26, 2002.
- Railroad Commission of Texas. E-mail to Susan Prosperie (TDH) from Heidi Bojes, RCTToxicologist concerning update on the Ballard Pits area sampling results. October 2,2002.
- Railroad Commission of Texas. E-mail to Susan Prosperie (TDH) from Heidi Bojes, RCTToxicologist, regarding Ballard Pits sampling data. January 8, 2002.
- Railroad Commission of Texas. Letters to residents explaining results of residential soiland well water sampling. October 14, 2002; October 23, 2002; January 10, 2003; January22, 2003.
- Railroad Commission of Texas. E-mail to TCEQ from David Cooney, Legal Counsel forRCT regarding environmental sampling analytical results of pit contents and residentialwater well and soil sampling results. January 22, 2003.
- Agency for Toxic Substances and Disease Registry. Public health assessment guidancemanual. Atlanta: U.S. Department of Health and Human Services, 1993.
- Agency for Toxic Substances and Disease Registry. Toxicological profile for arsenic(update). Atlanta: U.S. Department of Health and Human Services, September 2000.
- Tseng, WP, Chu HM, How SW, et al. Prevalence of skin cancer in an endemic area ofchronic arsenicism in Taiwan. J Natl Cancer Inst 1968;40:453-463.
- United States Environmental Protection Agency, Integrated Risk Information System.URL: http://www.epa.gov/iris/index.html . Arsenic. 8 November 1999.
- Smith, AH, et al. Cancer Risks from arsenic in drinking water. Environmental HealthPerspectives. 1992;97:259-267.
- Agency for Toxic Substances and Disease Registry. Toxicological profile for barium.Atlanta: U.S. Department of Health and Human Services, July 1992.
- United States Environmental Protection Agency, Integrated Risk Information System.URL: http://www.epa.gov/iris/index.html . Barium. November 8, 1999.
This Ballard Sand Pits public health consultation as prepared by the Texas Department ofHealth under a cooperative agreement with the Agency for Toxic Substances and DiseaseRegistry (ATSDR). It is in accordance with approved methodology and proceduresexisting at the time the public health consultation was initiated.
Technical Project Officer, SPS, SSAB, DHAC, ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this publichealth consultation and concurs with its findings.
Chief, State Programs Section, SSAB, DHAC, ATSDR
|ATSDR||Agency for Toxic Substances and Disease Registry|
|CCNCHD||Corpus Christi Nueces County Health Department|
|CDI||Chronic Daily Intake|
|CREG||Carcinogenic Risk Evaluation Guide|
|CSF||Cancer Slope Factor|
|EMEG||Environmental Media Evaluation Guide|
|EPA||United States Environmental Protection Agency|
|HAC||Health Assessment Comparison Value|
|MCL||Maximum Contaminant Level|
|MRLs||Minimal Risk Levels|
|NOAEL||No Observed Adverse Effect Level|
|QA/QC||Quality Assurance/Quality Control|
|RMEG||Reference Dose Media Evaluation Guide|
|RCT||Railroad Commission of Texas|
|SVOCs||Semi-volatile Organic Compounds|
|TCEQ||Texas Commission on Environmental Quality|
|TDH||Texas Department of Health|
|TDS||Total Dissolved Solids|
|TNRCC||Texas Natural Resource Conservation Commission|
|TPH||Total Petroleum Hydrocarbons|
|VOCs||Volatile Organic Compounds|
|Health Concern||People with Concern|
|Cancer - Skin (localized)||3||(1.90)|
|Psychiatric - Depression/Anxiety||3||(1.90)|
|Cancer - Blood||1||(0.60)|
|Cancer - Not Specified||1||(0.60)|
N = 160 (Total number of people in survey)
"n"=Number of people with concern
CVD - Cardiovascular disease
|Constituent||East Pit Range (mg/kg)||West Pit Range (mg/kg)||HAC Value (mg/kg)|
|10 CREG1 |
|all nd |
|0.1 CREG |
|PCBs||(<0.115)*-2.93||0.478-17.8||1/10 chrEMEG2; 0.4 CREG|
| Arsenic |
20/200 chrEMEG; 0.5 CREG
400 EPA action level
* none above health-based screening values
** none was the more toxic chromium VI; therefore this constituent was dropped from further evaluation.
J - estimated value
1 Carcinogenic Risk Evaluation Guide
2 Environmental Media Evaluation Guide
3 Reference Dose Media Evaluation Guide
|Arsenic Level (µg/L)||# Liters a 10 kg child would have to drink to exceed the CDI1||# Liters a 70 kg adult would have to drink to exceed the CDI|
|Dose of 12 µg/kg/day2||Dose of 100 µg/kg/day||Dose of 12 µg/kg/day||Dose of 100 µg/kg/day|
1 Chronic Daily Intake
2 Micrograms per kilogram per day
|Arsenic Levels in Residential Water Wells (µg/L)||Calculated Increased Risk of Developing Cancer||Qualitative Increased Risk of Developing Cancer over a Lifetime|
|7.28||1.28E-04||Low increased risk|
|15.8||2.78E-04||Low increased risk|
|16.8||2.96E-04||Low increased risk|
|17.1||3.01E-04||Low increased risk|
|17.8||3.14E-04||Low increased risk|
|21.4||3.77E-04||Low increased risk|
|27.8||4.90E-04||Low increased risk|
|28.1||4.95E-04||Low increased risk|
|32||5.64E-04||Low increased risk|
|33.7||5.94E-04||Low increased risk|
|33.8||5.94E-04||Low increased risk|
|34||5.99E-04||Low increased risk|
|34||5.99E-04||Low increased risk|
|34.7||6.11E-04||Low increased risk|
|39||6.87E-04||Low increased risk|
|45.2||7.96E-04||Low increased risk|
1 Abbreviations and Acronyms are listed and described in Appendix A.
2 The highest exposure level at which there were no statistically or biologically significant increases in the frequency or severity of adverse effects between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered adverse, nor precursors to adverse effects.