PUBLIC HEALTH ASSESSMENT
TINKER AIR FORCE (SOLDIER CR/BUILDING 3001)
MIDWEST CITY, OKLAHOMA COUNTY, OKLAHOMA
Contaminants disposed (released) into the environment are a public health concern if exposuresto the contamination could result in adverse health effects. However, for adverse health effectsto occur from contamination, two principle criteria must be met: The exposure pathway must becompleted, and the exposure concentration must be sufficient to cause adverse health effects. Arelease of a contaminant to the environment does not always result in exposure. People areexposed to a contaminant only if they come in contact with it. For example, exposure may occurby breathing, eating, or drinking a substance containing the contaminant, or by having skincontact with a contaminant or a substance containing the contaminant. Several factors determinethe type and severity of health effects associated with exposure to a contaminant: exposureconcentration (how much); the frequency and/or duration of exposure (how long); the route orpathway of exposure (breathing, eating, drinking, or skin contact); and the multiplicity ofexposure (combination of contaminants). Once exposure takes place, characteristics such as age,sex, nutritional status, genetics, lifestyle, and health status of the exposed individual influencehow the individual absorbs, distributes, metabolizes (processes), and excretes (eliminates) thecontaminant. Together, those factors and characteristics determine the health effects that mayresult from exposure to a contaminant. ATSDR considers the previously described physical andbiologic characteristics when evaluating site-specific exposures.
Toxicological profiles prepared by ATSDR summarize chemical-specific toxicologic and adversehealth effects information. Health guidelines, such as ATSDR's minimal risk level (MRL) andEPA's reference dose (RfD) and cancer slope factor are included in the toxicological profiles. Those guidelines are used by ATSDR public health professionals to determine an individual'spotential for developing adverse health effects from exposure to a hazardous substance.
Health guidelines, such as MRLs and RfDs, provide a basis for comparing estimated exposureswith concentrations of contaminants in different environmental media (soil, air, water, and food)to which people might be exposed. Health guidelines are generally considered to have a degreeof uncertainty; the values are calculated from scientific studies using standardized uncertaintyfactors. Therefore, health guidelines should not be considered strict scientific boundariesbetween toxic and nontoxic levels.
An MRL is defined as an estimate of the daily human exposure to a contaminant that is likely tobe without an appreciable risk of adverse noncancerous health effects over a specified duration ofexposure (acute, 1-14 days; intermediate, 15-365 days; chronic, more than 365 days). Currently,MRLs are not derived for dermal exposure. EPA's RfD and RfC are estimates of the dailyexposure of the human population, including sensitive subpopulations, that is likely to be withoutappreciable risk of adverse noncancerous health effects during a lifetime (70 years). Themethods used to derive MRLs and RfDs do not consider information about cancer; therefore,these guidelines do not imply anything about the presence, absence, or level of cancer risk. Theavailable guidelines for cancer-causing substances include the weight-of-evidence ofcarcinogenicity and the cancer slope factor. The weight-of-evidence classification reflects ajudgement of the likelihood that a chemical is a human carcinogen. EPA's cancer slope factor isused to determine the number of excess cancers expected from exposure to a contaminant.
Using the available health guidelines and scientific information, ATSDR determines thelikelihood that an adverse health effect, cancerous and/or noncancerous, will occur as a result ofexposure to contamination. Cancerous and noncancerous health effects occur via differentbiological mechanisms, and therefore, are evaluated separately using different health guidelinesand scientific information. If either cancerous or noncancerous health outcomes are expected tooccur as a result of exposure to contaminants, the exposure is determined to be of public healthconcern.
To link a site's exposure potential with health effects that may occur under site-specificconditions, ATSDR estimates exposure to site contaminants from ingestion and inhalation ofdifferent environmental media.48 The following relationship is used to determine the estimatedexposure to a site contaminant:
- ED = (C x IR x EF) / BW
ED = exposure dose (mg/kg/day)
C = contaminant concentration
IR = intake rate
EF = exposure factor/frequency
BW = body weight
Routes of exposure identified by ATSDR's public health evaluation are through private drinkingwater wells, base supply wells, the sediment and surface waters of East Soldier Creek, thesediment of West Soldier Creek and Crutcho Creek, and air in the vicinity of the IWTP.
To estimate exposures to contaminated drinking water, ATSDR used standard intake rates of 2liters (L)/day for adults and 1 L/day for children. Past exposures through ingestion wereestimated assuming a 40 year exposure period (based on when the base was first established). This is a very conservative exposure duration and is protective of people who have lived in thisneighborhood since the 1950s. To estimate exposures to contaminated sediment and soil,ATSDR used standard soil ingestion rates of 50 mg/day for adults and 100 mg/day for children. Standard body weights for adults and children are 70 kg and 10 kg, respectively. The maximumcontaminant concentration detected in a specific medium at the point of exposure was used todetermine the estimated exposure; using the maximum concentration results in an evaluationmost protective of public health. When unknown, the biologic absorption from an environmentalmedium, such as water, is assumed to be 100%.
To evaluate environmental exposures to contaminated surface water and sediment, on- and off-site exposure scenarios were developed. ATSDR assumed that children come in contact with thecreeks (play/wade/swim) 90 days a year [five days a week during the summer (June-August) andonce a week during the fall and spring]. Standard ingestion rates do not exist for incidentalingestion of surface water while playing in streams. An ingestion rate of 50 ml/day for childrenwas used to estimate incidental ingestion of surface water while playing in the creeks.78 Thisvalue is representative of incidental ingestion of water during swimming activities.
ATSDR assumed workers on base were exposed to contaminated sediments and surface watersvia ingestion and dermal contact 5 days a week, 50 weeks a year for 20 years (common workerscenario). This scenario is conservative for most workers on base, most will actually be exposedless frequently. ATSDR has identified no job on base that would result in daily exposure tosediments. However, this approach includes any future scenario for workers.
People have been exposed to multiple contaminants as a result of exposure to contaminatedwater, sediments, and air. However, few data are available on the health effects of exposure tomultiple contaminants. Effects of exposure to multiple contaminants can be additive, synergistic(greater than the sum of single contaminant exposures), or antagonistic (less than the sum ofsingle contaminant exposures). Because of the many uncertainties surrounding exposure tomultiple contaminants, ATSDR's evaluation of multiple exposure is limited.
Site-specific contaminant exposures for each pathway are discussed below. Additionaltoxicologic information is provided in Appendix H for contaminants that are determined to be ofpublic health concern.
In September - November 1983, VOCs were detected in base supply wells 18 and 19. Concentrations in well 18 were significantly elevated (Table 2). In response to the samplingresults, the Air Force removed the wells from the base supply system in 1984. Therefore, on-base exposure to VOCs occurred prior to 1984. Contaminants detected includedtrichloroethylene, tetrachloroethylene, 1,1,2-trichloroethane, 1,1-dichloroethane, and 1,2-dichloroethane.
ATSDR was unable to determine the concentrations people were exposed to, duration of theexposure, or population that was exposed. It is likely that the concentrations that people wereexposed to were less that those detected in well 18 (1642 ppb, TCE). Water is pumped into thedistribution system with holding tanks positioned along the system. Therefore, the addition ofuncontaminated water from other base supply wells would dilute the concentrations ofcontaminants in the water delivered at the taps. However, it is likely that even following dilutionpeople were exposed to concentrations of TCE above the MCL of 5 ppb. An estimate of howlong base wells 18 and 19 were contaminated prior to closure in 1984 is difficult to determine. Sampling was not required prior January 1988 (Safe Drinking Water Act). Therefore, samplingresults are not available to determine when the wells became contaminated. Water usage withinthe system is somewhat localized, water pumped into the distribution system from a supply wellis largely used by patrons within close proximity of the holding tank for that well.79 Therefore,people working on base in areas near well 18 are the persons with the highest potential for pastexposure. Persons in these areas would have been exposed through ingestion of water, inhalationof the volatilized contaminants, and dermal contact with the water. ATSDR considers this pastexposure to be of public health concern because the concentrations in well 18 were significantlyelevated above drinking water standards and the contaminants detected are classified as probablecarcinogens. These exposures are discussed in the 1988 Public Health Assessment (Appendix A). Since 1984, VOCs above drinking water standards have not been detected in the base supplywells that have been in use.
Lead, arsenic, and selenium were detected (1986-1990) above ATSDR health guidelines forchronic exposure in base supply wells 13 and 14 (Table 3). The base was not out of compliancewith regulatory values at the time of analysis. But with new available scientific information,exposures to these concentrations are potentially of concern today. Therefore, the metals wereincluded as contaminants of concern in Table 3. However, based on a worker exposure scenario,adverse health effects are not expected to occur as a result of exposure to the concentrations oflead, arsenic, or selenium detected in the base supply wells. Children, the most sensitivepopulation, are not expected to be exposed to water from these supply wells. The drinking waterat the on-base Child Development Center is provided by the base distribution system and is amixture of municipal and base water. Current sampling has shown that the mixture of municipaland base water supplied to the Child Development Center is in compliance with the SafeDrinking Water Act.
Exposure to contaminants in private well water occurred via ingestion, inhalation, and dermalcontact. VOCs detected in private wells at concentrations above health comparison valuesinclude TCE, PCE, benzene, and 1,2-DCA. Barium, was also detected in a private well abovethe health comparison value. This sampling data is presented in Table 4. The ingestion route ofexposure ceased when residents were supplied bottled water for drinking and cooking. However,because well water was used for other household purposes, such as showers and laundry,exposures through inhalation of the volatilized contaminants and dermal contact continued untilthe homes were provided municipal water.
Exposure via inhalation of VOCs volatilized from domestic use of water (showering, washing,cooking, etc) is expected to be at least equivalent to that from ingestion.80 Dermal absorption ofVOCs vapor through the skin is negligible. However, absorption of VOCs solubilized in watermay be significant.81 Therefore, total daily exposure (ingestion, inhalation, and dermal contact)is expected to be approximately two to three times the estimated daily ingestion exposure.
- Trichloroethylene (TCE)
TCE was detected at a maximum concentration of 13.8 ppb in private wells. Using themaximum detected concentration, the daily estimated exposure to TCE from past ingestion ofcontaminated well water is 0.0004 mg/kg/day for adults and 0.0014 mg/kg/day for children. Assuming a total exposure (ingestion, inhalation, and dermal contact) of three times the dailyestimated exposure from ingestion (most conservative estimate), total exposure was 0.0012mg/kg/day for adults and 0.0042 mg/kg/day for children. The MRL for intermediate exposure(daily exposures of less than one year's duration) is 0.7 mg/kg/day.82 A health guideline forchronic TCE exposure has not been developed.
The estimated exposure for children and adults is less than the intermediate-MRL. Therefore,adverse noncancerous health effects are not expected to result from intermediate exposures toTCE-contaminated drinking water in neighborhoods near Tinker. It is unlikely that chronicexposures to contaminated water near Tinker would result in adverse noncancerous healtheffects. Studies of animals have indicated that chronic TCE exposure may result in adversedevelopmental, heart, kidney, or liver effects.82 However, exposures in those studies werethousands of times greater than the expected exposures of people living near Tinker.
Populations that may be susceptible to chronic TCE exposure include people who consumealcohol, people treated with disulfiram, and people who have liver dysfunction or heartconditions. Fetuses in the first trimester (first three months of pregnancy) may be a population ofparticular concern. Epidemiologic studies have associated chronic exposure to TCE-contaminated drinking water (6-239 ppb) with congenital heart defects.83 The significance ofthis finding is questionable because of the possibility that the women were exposed to multiplechemicals. Congenital heart defects resulting from TCE exposure also have been reported inanimals.84,85
There is some uncertainty as to the carcinogenicity of TCE. EPA has classified TCE as aprobable human carcinogen by way of ingestion.55,82 However, the cancer classification andslope factor are currently being reviewed by EPA. The National Toxicology Program does notconsider TCE a carcinogen.82 Therefore, the evaluation of cancer risk as a result of exposure toTCE is questionable. Using the cancer slope factor, a small increase in cancer risk may beexpected as a result of exposure to TCE-contaminated water. Only people who were exposed forover five years at the maximum concentrations detected are expected to have an increased risk ofdeveloping cancer as a result of the exposure. Therefore, an increase in cancer rates due to TCEexposure would be undetected in the population near Tinker because only a small number ofpeople were exposed to the maximum concentrations, the increased cancer risk is small, andbecause the average cancer incidence in an area has a number of causes.
- Tetrachloroethylene (PCE)
PCE was detected in private wells at a maximum concentration of 20.1 ppb. Assuming a totalexposure of three times the daily estimated exposure from ingestion (most conservativeestimate), total exposure would be 0.002 mg/kg/day for adults and 0.006 mg/kg/day for children. The chronic RfD for PCE is 0.01 mg/kg/day which is greater than the estimated exposures.86 Therefore, adverse noncancerous health effects in children or adults as a result of exposure toPCE-contaminated water are not expected to occur.
The EPA has classified tetrachloroethylene as a probable human carcinogen through ingestionand inhalation based on epidemiological studies of workers exposed to PCE and animals studies. The National Toxicological Program considers PCE to be a reasonably anticipated carcinogen. Based on risk calculations, there is no increased cancer risk from exposure to PCE at theconcentrations detected.
Benzene was detected at a maximum concentration of 21 ppb (October 8, 1991) in one of twosupply wells at the Evergreen Trailer Park. However, the contaminated well was not being usedas a potable source of water when the contamination was detected.87 The well may have beenused for other nonpotable purposes, however, and people may have been exposed by dermalcontact and inhalation of volatilized contaminants. Three days after the contamination wasdetected, bottled water was provided as a preventive measure to the trailer park. The length oftime that people were exposed at the trailer park cannot accurately be determined. However, the exposure duration was less than 16 months because contamination was not detected duringanalysis of samples collected from both wells in June 1990.87
The MCL (long term exposure) for benzene is 5 ppb. This regulation is based on preventingleukemia.88 The maximum concentration detected in the supply well was greater than the MCL. However, the people were not using the water as the potable source for the trailer park. The level for short-term exposure (ten days) is 235 ppb for children.
Using the maximum concentration detected and assuming that people were drinking the water(the worst-case scenario), the estimated exposures from ingestion of water are 0.002 mg/kg/dayfor children and 0.0006 mg/kg/day for adults. Total estimated exposures are 0.006 mg/kg/dayand 0.0018 mg/kg/day for children and adults, respectively. Animal studies have reported a no-observed-adverse effect level (NOAEL) at 1 mg/kg/day. The NOAEL is more than a hundred-fold greater than the estimated exposures of a worst-case scenario. Therefore, it is unlikely thatnoncancerous adverse health effects would occur as a result of exposures to benzene in the trailerpark well.
Benzene can enter your body through the skin. However, studies regarding human dermalexposure to benzene were not reported.88 Adverse dermal effects have been observed inlaboratory animals following skin contact with undiluted benzene. However, dermal contactwith benzene similar to the concentrations detected in private wells near Tinker should not be ofpublic health concern.
EPA estimates that exposure to 10 ppb benzene in drinking water over a lifetime could increasethe risk of cancer by one case for every 100,000 exposed persons.89 The DHHS, IARC, ACGIH, OSHA, and WHO also consider benzene to be a human carcinogen. People at the Evergreen Trailer Park were not using the water as a potable source of water and nonpotable exposures were less than 16 months in duration. Therefore, adverse cancerous health effects are not expected tooccur as a result of the exposures. Benzene was detected at 9.8 ppb in one private well beingused for drinking water. The exposure duration for this well was not determined. Longtermexposure to benzene at this concentration in drinking water may increase the risk of developingcancer. Benzene was detected at 1.8 ppb in one additional private well, but adverse health effectsare not expected as a result of the exposure.
- 1,2-Dichloroethane (1,2-DCA)
A maximum concentration of 46 ppb of 1,2-dichloroethane (1,2-DCA) was detected in a privatewell northeast of Tinker. 1,2-DCA was detected in three other wells but, the concentrations weremuch lower; 8.54 ppb, 2.38 ppb, and < 1 ppb. The concentrations of 1,2-DCA that causeparticular non-cancerous adverse health effects in humans are unknown.91 Most of the effectsseen in humans have occurred after accidental ingestion of large amounts or after exposure viainhalation to unknown levels of 1,2-DCA.
Health-based drinking water advisory levels are available. For children, the longer-term healthadvisory (CLHA) value is 740 ppb and for adults it is 2600 ppb. Since the maximumconcentration of 1,2-DCA detected is considerably less than the health advisories, past exposuresto 1,2-DCA via ingestion are not expected to result in noncancerous adverse health effects.
People can be exposed to 1,2-DCA through the skin. Dermatitis may result from prolonged skincontact with 1,2-DCA; however, concentrations at which this occurred were not reported.90 Also, skin lesions in animals have resulted from dermal exposure to 1,2-DCA and it is likely thathighly concentrated solutions of 1,2-DCA would have this effect on humans, too.91 Becausehighly concentrated 1,2-DCA levels are not expected to come from private well water nearTinker, no adverse dermal effects are expected.
Based on animal studies, the EPA has classified 1,2-DCA as a probable human carcinogen viainhalation and ingestion.89 Using the EPA cancer slope factor, an increased risk of developingcancer is expected as a result of exposure to the maximum concentration of 1,2-DCA detected. However, adverse cancerous health effects are not expected as a result of exposure to theconcentrations detected in the other three wells.
Barium was detected in a private well at a maximum concentration of 1220 ppb. Bariumconcentrations in groundwater supplies sometimes will exceed EPA's MCL of 1000 ppb; thismay be due to leaching and erosion of barium from sedimentary rocks.92
The estimated exposure through ingestion is 0.034 mg/kg/day for adults and 0.122 mg/kg/day forchildren. The estimated dose for children exceeds the oral RfD of 0.07 mg/kg/day. However,barium is poorly absorbed by the gastrointestinal (GI) tract and it is estimated that the GIabsorption of barium is less than five percent.92
Adverse health effects have not been reported following exposure to barium concentrationssimilar to those detected in the private well. Most of the data on health effects of barium comefrom studies in which a small number of people were exposed to fairly large amounts of bariumfor a short time.92 Information is currently being collected to find out if long-term exposure tolow levels of this metal causes any health problems.92
Barium is not expected to volatilize from water during household use. Thus, adverse healtheffects are not expected to result from inhalation of barium from private wells near Tinker.Health effects have been shown to occur from occupational exposure to high but unknownbarium levels in air.92 However, these exposures occur in occupational settings with extremetemperatures. Barium has a vapor pressure of 10 mmHg at 1049 degrees Fahrenheit.
At pH levels of 9.3 or below (pH range for private well water was 6.0 - 7.0), the barium ion (Ba2)is the predominant species.66 Often the water will contain enough sulfate that a barium ionconcentration of more than 1,000 - 1,500 ppb is not maintained in solution. Most bariumcompounds are highly polar (dissociates to form ions in water); polar compounds are generallypoorly absorbed through the skin.93 Therefore, exposure to barium at the concentrationsdetected at Tinker is not expected to result in significant dermal uptake of the chemical. Noadverse health effects are expected to result from skin contact with barium in private well water.
Barium is not known to cause cancer in humans through any route of exposure.
There were several sampling locations of sediment along East Soldier Creek. ATSDR focusedon locations E09, E10, and E11 because of the potential for human exposure in those areas(Figure 7). Contaminants detected above health comparisons values at the above locations areevaluated in relationship to the exposure expected at that location. The public health significanceof exposure to the maximum concentration detected is also reported. The location and maximumconcentration detected in sediments in East Soldier Creek are listed in Table 6.
Cadmium was detected at a concentration of 10.5 ppm in sediment in the area behind theEvergreen Trailer Park (sample E11). Based on the most likely exposure scenario describedpreviously, the estimated exposure for children playing along the creek is 0.000004 mg/kg/dayfrom incidental ingestion of sediment. This value is one hundred-fold less than the oral MRL forcadmium, a daily lifetime exposure guideline. Even daily exposure to the concentrations ofcadmium detected in sediment would not result in exposures greater than the MRL. Moreover,most ingested cadmium passes through the GI tract without being absorbed.94 Therefore,exposure to cadmium in the sediments of East Soldier Creek in this area are not expected toresult in adverse health effects.
Cadmium was detected at 324 ppm at sampling site E09, an outfall of Building 3001. This wasthe maximum detected concentration in East Soldier Creek. Assuming on-base workers areexposed five days a week, the estimated exposure is ten fold less than the MRL. Therefore, oralexposure to cadmium in the sediments near the outfalls are not expected to result in adversehealth effects.
Daily exposure of children to the maximum concentration of 324 ppm may result in a slightincreased risk for adverse health effects. However, it is very unlikely that children would beexposed daily to the maximum concentration because the location is not accessible to childrenand children are not expected to play in the creek on a daily basis.
Very little cadmium enters the body through skin, so dermal contact with cadmium contaminatedsediments at the above sites is not expected to result in adverse health effects.94
Guidelines to estimate cancer risk from oral exposure to cadmium are not available becausestudies of human ingestion of cadmium are inadequate to assess carcinogenicity.55 A few studiesof cancer rates among people exposed to cadmium orally have been reported. No significantincrease in cancer rates was found. Overall, there is little evidence of an association between oralexposure to cadmium and increased cancer rates in people. However, the studies areinconclusive. The EPA has classified cadmium as a probable human carcinogen by inhalationbased on limited evidence from occupational epidemiologic and laboratory animal studies. However, exposure to cadmium by inhalation was not identified as a route of exposure for thissite.
In the laboratory analysis for beryllium, the sample detection limit was greater than the CREG. Beryllium concentrations were, therefore, reported as the detection limit. This means the preciseconcentrations in the samples are unknown, but the actual concentrations are less than or equal tothe reported value. The reported values were 0.62 ppm at E09, 0.31 ppm at E10 (DouglasBoulevard bridge), and 0.68 ppm at E11 (Evergreen Trailer Park). The maximum concentrationreported was 0.77 ppm at E12.
Using the reported value (a conservative estimate), no increased cancer risk is expected fromexposure to beryllium via incidental ingestion of sediment in East Soldier Creek. The estimatedexposures are also below health guidelines for noncancerous adverse health effects. Therefore,adverse health effects are not expected to result from incidental ingestion of sediments containingberyllium.
Very little beryllium is expected to enter the body from skin contact with contaminated soil. Thus, dermal contact with beryllium at the above sites is not expected to result in adverse healtheffects.95
Several PAHs, both carcinogenic and noncarcinogenic, were detected in East Soldier Creeksediment above health comparison values. Carcinogenic PAHs detected include:benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene,pyrene, and indeno(1,2,3-cd)pyrene. Noncarcinogenic PAHs detected include: acenaphthene,phenanthrene, and benzo(g,h,i)perylene.
All noncarcinogenic PAHs detected in the sediments at E09, E10, and E11 are over a thousand-fold less than risk-based concentrations for residential soil.96 From all the sampling locations onEast Soldier Creek, E03 had the maximum concentration of noncarcinogenic PAHs. However,concentrations at E03 were more than 300-fold less than the risk-based concentrations. Therefore, noncancerous adverse health effects are not expected as a result of exposure to sediments in East Soldier Creek.
A method using toxicity equivalency factors (TEFs) has been developed for evaluatingcarcinogenic PAHs. Benzo(a)pyrene is the more carcinogenic of the PAHs and is used as thereference compound in this type of evaluation. The method is based on each compounds relativepotency to the potency of benzo(a)pyrene. The other carcinogenic PAH concentrations are madeequivalent to the reference compound, benzo(a)pyrene.97
The TEF adjusted total concentrations of carcinogenic PAHs are 1.7 ppm at E09, 2.9 ppm at E10,and 0.2 ppm at E11. Based on a cancer slope factor of 5.8 (mg/kg/day)-1, cancerous health effectsfrom incidental ingestion exposure to sediment at locations E09, E10, and E11 are not of publichealth concern. Daily exposure to sediments at location E03 (location with maximum adjustedconcentration of 16.6 ppm) may result in a slight increase in cancerous effects. However, dailyexposure is not expected at this location and infrequent exposure is not a concern.
Chronic dermatitis and hyperkeratosis have been seen in workers exposed chronically tosubstances that contain PAHs. However, those exposures have been at much greaterconcentrations than those at Tinker. Absorption of PAHs from dermal contact with soil isexpected to be minimal. Studies using human skin reported only 3% permeation of an applied dose of benzo(a)pyrene after 24 hours.98 Thus, skin contact with PAH-contaminatedsediment at Tinker is not expected to cause adverse noncancerous health effects.
- Other contaminants
The maximum concentration of lead detected in sediment was 586 ppm at location E09.Exposure to sediment with this concentration of lead is not of public health concern for workers. Daily exposure of children to sediment at this location in the creek may be of slight concern. However, in general, children are not expected to be exposed to sediments in the creek on a dailybasis. In addition, exposure of children at this location is not expected to occur.
Chromium was detected at 1190 ppm at E09 (maximum detected in East Solider Creek). Thechromium was not speciated (chromium III vs. chromium VI). The EPA Region III residentialsoil risk-based concentration is 390 ppm and 78000 ppm for chromium VI and III, respectively.96 Even if the contaminant is 100% chromium VI, the more toxic form, this level is not a concernfor exposure to workers or infrequent exposure of children. However, daily exposure of childrenmay be of public health concern if the contaminant is 100% chromium VI. The typical ratio ofchromium discharged from the IWTP is one part chromium VI to five parts chromium III.67 Inaddition, chromium VI can be reduced to chromium III by organic matter in water.99 Therefore,it is unlikely that adverse health effects would result from daily exposure of children to thesediment.
Some contaminants were detected at locations other than E09, E10, and E11. Thesecontaminants and location of maximum detection include the following: tetrachloroethylene(E03), dibenzofuran (E03), DI-n-butylphthalate (E08), magnesium (E02), and manganese (E02). These contaminants were detected in locations that were determined not to be primary points ofexposure. Exposures at these locations would be infrequent and the levels are not elevated. Therefore, adverse health effects are not expected from exposure to these chemicals.
The majority of water in East Soldier Creek is released from the IWTP [900,000 gallons per day(gpd) flow generated by IWTP].5 Therefore, ATSDR assumes that water quality in East SoldierCreek downstream from the IWTP is similar to effluent from the plant. Unlike the evaluation ofsediment, surface water in East Soldier Creek is not evaluated specific to the location since thewater will flow from the IWTP and downstream to all locations. Maximum concentrationsdetected in the Soldier Creek RI/FS (presented in Table 5) are used to evaluate exposure. Theavailable health guidelines cited in Table 5 are drinking water standards and are based on intakerates greater than those expected for a nonpotable surface water source. These guidelines arevery conservative when used as nonpotable water standards. Inhalation was not considered as aroute of exposure for metals because metals are not expected to volatilize from the creeks. Theconcentrations detected in the RI/FS study are considered to be representative of surface water,except during times of NPDES noncompliance discharges. Exposure as a result of NPDESnoncompliance discharges are discussed separately. The NPDES data is presented in Table 7.
Bromodichloromethane was detected in surface water at a maximum concentration of 6 ppb. Estimated exposure by incidental ingestion is 1000-fold less than the oral RfD forbromodichloromethane.55 Dermal and inhalation exposures at the reported concentrations wouldnot be significant. Also, no increased cancer risk from exposure to bromodichloromethane isexpected. Thus, neither cancerous or noncancerous adverse health effects are expected to resultfrom exposure to this contaminant in East Soldier Creek surface water.
- Tetrachloroethylene (PCE)
PCE was detected in surface water at a maximum concentration of 3 ppb. Estimated ingestiondoses are tenfold below the oral RfD for PCE. Dermal and inhalation exposures at the reportedconcentrations would not be significant. Also, there is no increased cancer risk from exposure toPCE. Thus, both cancerous and noncancerous adverse health effects are not expected to resultfrom exposure to this contaminant in East Soldier Creek surface waters.
There are three major species of chromium: chromium VI, chromium III, and chromium 0. Chromium VI is irritating and short-term high-level exposure may result in adverse health effectsat the site of contact.99 Chromium III does not result in these effects and is thought to be anessential food nutrient when taken in small amounts, although large amounts may be harmful.99 Exposure to chromium 0 is less common and is not well characterized in terms of exposurelevels or potential health effects.
Chromium was not speciated during analysis of East Soldier Creek surface water samples. Therefore, ATSDR used health guidelines for chromium VI, the more toxic species, to evaluatepotential toxicity from exposure. ATSDR used the more conservative values because chromiumVI is being used in industrial operations at Tinker. However, the typical ratio of chromiumdischarged from the IWTP is one part chromium VI to five parts chromium III.67 In addition,chromium VI can be reduced to chromium III by organic matter present in water.55 Therefore, itis unlikely that the chromium detected is 100% chromium VI.
Chromium was detected in the surface water at a maximum of 156 ppb. The estimated oralexposures are tenfold below the oral RfD for chromium VI. In addition, the estimated exposureis much less than the upper range of the estimated safe and adequate daily dietary intake of 0.2mg/day.99 Thus, noncancerous adverse health effects are not expected to result from oralexposure to chromium in East Soldier Creek surface waters.
It is unlikely that exposures to chromium in the sediment of East Soldier Creek would increasethe risk of cancer. The EPA classifies chromium VI as a known human carcinogen via inhalationbased on occupational epidemiologic studies of chromium-exposed workers. Inhalation andintratracheal studies with chromium (VI) compounds in animals also support the carcinogenicfindings in humans.99 However, exposure to chromium VI by inhalation was not identified as aroute of exposure for this site. There are no long-term studies that suggest that cancer isassociated with ingestion of chromium VI.55,99
Manganese was detected in East Soldier Creek surface waters at a maximum concentration of493 ppb. The estimated oral exposure dose is tenfold less than the RfD for manganese. Verylittle manganese will enter your body through your skin, so dermal contact is not of concern.100 Therefore, noncancerous adverse health effects are not expected to result from contact withmanganese in East Soldier Creek surface waters.
Existing studies, both human and animal, are inadequate to assess the carcinogenicity ofmanganese.55
Arsenic was reported at a maximum concentration of 6.4 ppb in surface water. The reportedvalue is the detection limit for the analysis. Therefore, concentrations are equal to or less thanthe value reported. Using the maximum value as a conservative estimate, the estimated ingestionis tenfold less than the RfD for arsenic. Small amounts of arsenic may enter the body through theskin, but this is not usually an important consideration.101 Also, no increased cancer risk isexpected to result from arsenic contaminated surface water based on calculations using thecancer slope factor for arsenic. Therefore, noncancerous and cancerous adverse health effects arenot expected to result from oral exposure to arsenic in East Soldier Creek surface waters.
- NPDES Permit Violations - Potential Exposures
The IWTP has a NPDES permit to discharge treated industrial wastewater to East Soldier Creek. Approximately 900,000 gallons of treated effluent are generated per day; this discharge createsthe majority of water flow in the creek.5 Therefore, ATSDR assumes the water qualitydownstream from the IWTP is similar to effluent from the plant.
The Clean Water Act controls the direct discharge of pollutants to surface waters through theNPDES program.102 NPDES requires permits for direct discharges to surface waters, such asEast Soldier Creek. The permit contains limits based upon either effluent standards, or, if theyare more stringent, ambient water quality standards. NPDES permit limits are set according tothe best available technology economically achievable. The permit limits are often lower thandrinking water standards. Therefore, in general, adverse health effects from exposures to thetreated water discharged to East Soldier Creek are not expected. However, during permitviolations, it would be possible for concentrations in the surface water to reach levels that are ofpublic health concern. Therefore, ATSDR reviewed NPDES reports from September 1988through January 1994. The maximum concentrations released during noncompliance dischargesare reported in Table 7. ATSDR evaluated these NPDES discharges as possible short-termexposures to persons who come in contact with water in East Soldier Creek following a NPDESviolation.
Chemicals released to the creek and reported at concentrations in violation of the NPDES permitincluded: copper, total chromium, chromium VI, cyanide, zinc, phenol, cadmium, lead, andphosphorus. The average monthly and maximum effluent concentrations from 1988 to 1994 foreach of those chemicals are graphically presented in Appendix I. The graphs show therelationship of the NPDES permit limit, the health guideline, and the monthly effluentconcentrations (average and maximum) for each chemical.
The maximum reported NPDES violation for copper (1.0 ppm) is less than the MCLG (1.3 ppm). The ten-day health advisory for total chromium and chromium VI (1.4 ppm) is similar to themaximum reported NPDES violation (1.8 ppm). The LTHA for cyanide (0.15 ppm) is 2-foldgreater than the maximum permit violation (0.08 ppm). The MCLG, ten-day health advisory,and LTHA are drinking water guidelines. Incidental ingestion while playing or working near thecreek would be much less than the intake rate for a drinking water source.
The maximum reported NPDES violations for zinc, phenol, and cadmium are 18 ppm, 12 ppm,and 0.03 ppm, respectively. Using a daily intake rate of 50 milliliters (mls), the estimatedexposure to zinc (0.03 mg/kg/day) is 3-fold less than the RfD, the exposure to phenol (0.06mg/kg/day) is 10-fold less than the RfD, and the exposure to cadmium (0.0002 mg/kg/day) is 2.5-fold less than the RfD.
An appropriate health standard is not available for evaluating the exposure to lead in surfacewater. The maximum NPDES violation was 1.0 ppm. Only two violations of the permit for leadoccurred during the six years of reports that were reviewed. Adverse health effects are notexpected from an acute exposure to these concentrations in surface water.
The maximum NPDES discharge of phosphorus was 9.30 ppm. The NPDES permit analysis ofphosphorus includes both inorganic and organic phosphates.67 Phosphorus, in the form ofphosphate, is common to most foods. The average daily intake of phosphorus in the UnitedStates is approximately 1,500 mg. The Recommended Dietary Allowance (RDA) is 800 mg forchildren aged 1 to 10 and adults 19 years or more. Children between 11 and 18 and pregnant andnursing women should consume 1,200 mg daily.103
Assuming a daily consumption of 50 mls water/day via incidental ingestion of surface water fromEast Soldier Creek, the estimated exposure is less than 1 mg/day of phosphorus. This exposure is significantly less than the RDA for both children and adults.
The health standards used in the evaluation above are highly conservative when used to evaluatesurface water. In addition, the concentration reported during the NPDES violation does notrepresent daily concentrations in the surface water. Exposures to these elevated concentrationswould be infrequent.
In summary, evaluation of the NPDES violations from 1988 to 1994 determined thatconcentrations of chemicals released to the creek were not of public health concern. People mayhave been exposed to concentrations of contaminants similar to the concentrations dischargedduring a NPDES excursion. Those exposures are expected to be of short-term duration and arenot considered representative of chronic exposure. Exposures would occur by incidentalingestion of and dermal contact with the water.
Children may play in West Soldier Creek and could be exposed to contaminants in the sediments. ATSDR assumed that children come in contact with the creek (play/wade/swim) 90 days a year[five days a week during the summer (June-August) and once a week during the fall and spring]and ingest 100 mg of sediment and 50 ml of creek water each time they play. Of the samplinglocations, W07, near a trailer park, is the one where children would most likely play. Based onthe scenario above, children are not expected to have adverse health effects from exposure toWest Soldier Creek sediment.
Workers may be exposed to contaminated sediments in West Soldier Creek. Sampling locationsW03 and W04 are near outfalls of building 3001 where employees might be working. Uponevaluation of this pathway and the contaminants detected that have health comparison values (see Table 9), arsenic, beryllium, cadmium, chromium, manganese, and nickel do not pose a publichealth threat to workers. Polycyclic aromatic hydrocarbons, cobalt, and lead do not have healthcomparison values and are evaluated below.
- Polycyclic aromatic hydrocarbons (PAHs)
Using the TEF approach to evaluate the carcinogenic PAHs, the adjusted total PAHconcentration is 6.0 ppm. Daily exposure is not expected at this location and infrequent exposureis not a health concern.
Several PAHs, both carcinogenic and noncarcinogenic, were detected in West Soldier Creeksediment. Carcinogenic PAHs detected include: benz(a)anthracene, chrysene,benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene. Phenanthrene is the onlynoncarcinogenic PAH detected.
Benzo(b)fluoranthene and benzo(a)pyrene were detected in the sediments greater than dailyexposure risk-based concentrations for residential soil.96 However, people are not expected to beexposed daily to sediments in West Soldier Creek. Therefore, because people would be exposedinfrequently these contaminants do not pose a health concern.
Chronic dermatitis and hyperkeratosis have been seen in workers exposed chronically tosubstances that contain PAHs. However, those exposures have been at much greaterconcentrations than those at Tinker. Absorption of PAHs from dermal contact with soil isexpected to be minimal. Studies using human skin reported only 3% permeation of an applieddose of benzo(a)pyrene after 24 hours.98 Thus, skin contact with PAH-contaminated sediment inWest Soldier Creek is not expected to cause adverse noncancerous health effects.
Exposures of workers to cobalt in West Soldier Creek sediments are not expected to result inadverse health effects. Cobalt was detected at a maximum of 52.1 ppm in the sediment atsampling location W03 (next to Building 3001). The primary target organs for the effects ofcobalt in humans are the respiratory system following inhalation and the cardiac and bloodsystems following oral exposure.104 Effects of cobalt ingestion (cobalt sulfate in beer or cobaltchloride as treatment for anemia) that have been observed in humans include cardiomyopathy,gastrointestinal effects, visual disturbances, and thyroid effects. However, these adverse effectshave been observed following exposures to significantly higher (1000 fold) concentrations thanthose detected at Tinker.104 Cobalt has not been shown to cause cancer in humans by anyexposure route.
Exposure to the maximum concentration of lead in sediments of West Soldier Creek is not ofpublic health concern for workers or children. The maximum concentration of lead detected insediment was 243 ppm at location W03.
Children who play in and around West Soldier Creek could be exposed to contaminants in thesurface water. Sampling location, W07, is near a trailer park where children are most likely toplay in the stream. However, based on the concentrations detected no adverse health effects areexpected to result from exposures to surface water at this location.
Workers may be exposed to contaminated surface water in West Soldier Creek. Upon evaluation of this pathway and the contaminant concentrations detected (see Table 8), there is no apparent risk to the health of workers.
There were several sampling locations for sediment along Crutcho and Kuhlman Creeks. ATSDR focused on sampling locations 6-15 for Crutcho Creek and location 1 for KuhlmanCreek since they are in or near on-base neighborhoods and there is the potential for humanexposure, especially for children, in these areas. Evaluation of this pathway determined that thecontaminants detected with health comparison values (see Table 10), barium, beryllium,chromium, manganese, 4,4-DDD, and Aroclor-1260, do not pose a public health threat tochildren or adults. Arsenic is a Class A carcinogen and was detected at high levels off base andlead does not have any comparison values. Thus they are evaluated below.
For the sampling locations along Crutcho Creek in the areas where children might be exposed,arsenic was detected at a maximum concentration of 6.4 ppm at sampling location SD15E. Noadverse health effects are expected to result from exposures to arsenic at this concentration.
Arsenic was detected at a maximum concentration of 22.3 ppm at sampling location SDB1 whichis upstream of the base. This concentration represents concentrations coming onto the base andcannot be attributed to Tinker. Also, children are not expected to be in the area where thissample was taken. Thus, the arsenic levels detected in Crutcho Creek sediment do not pose apublic health threat.
Lead was detected at a concentration of 87 ppm at sampling location SD15E in the area wherechildren might be exposed. However, exposure to sediment with these concentrations of lead isnot of public health concern for children. The maximum concentration of lead detected was 309ppm at location SD26. Daily exposure of children to sediment at location SD26 in the creek maybe of slight concern. However, in general, children are not expected to be exposed to sedimentsin the creek on a daily basis. In addition, exposure of children at location SD26 is not expectedto occur.
Ambient air in the vicinity of the IWTP was identified as a completed pathway. In March 1994,ATSDR issued a Health Consultation based on the results of the 1993 air sampling program. The consultation is included in Appendix G.
In the consultation, ATSDR concluded that adverse health effects are not expected as a result ofexposure to ambient air concentrations detected in the 1993 IWTP ambient air study. However,current emissions of hydrogen sulfide may result in odors that are perceived as a nuisance to thelocal community. Emissions in the past may have been greater than the concentrations detectedin the 1993 IWTP study. However, based on the available data, past exposures cannot beadequately determined to evaluate those past exposures. ATSDR recommended that ambient airmonitoring stations be established in the vicinity of the IWTP and that the Air Force continue tomodify the IWTP to better control emissions from the facility.
Phenol was detected above the Oklahoma MAAC (Maximum Ambient Air Concentration) in theinitial ambient air sampling at the IWTP. The source of the contamination is believed to bevolatilization of VOCs from tanks D1/D2 and holding tanks at the IWTP.
The community is concerned about ambient air exposures in the past. In an effort to address pastexposure, ATSDR reviewed available influent phenol concentrations (January 1992 throughFebruary 1994) to the D1/D2 holding tanks at the IWTP.105 Influent concentrations of phenolpeak when stripping processes occur in Building 3001. The data show that the plant receivedsimilar peak concentrations of phenol over the two year period. One unusual influent peakoccurred during May 1993. The concentrations were about 2-fold greater than other peaks duringthe two year period. Ambient air concentrations of phenol were detected above the OklahomaMAAC during this month (the initial ambient air sampling). The ambient air samples collectedduring the air sampling program (discussed in the consultation) were taken during a month whenthe influent concentrations were similar to other months in 1992 and 1993. Therefore, the datashould be representative of exposures over this time period. Data is not available to addresspotential exposure prior to 1992.
The health outcome data available was reviewed by ATSDR and was determined as insufficientfor evaluation. The available statistics are reported at the county level and are not specific for theexposed population.
Mortality and death certificate data is available for Oklahoma County through the Center forDisease Control and Prevention's WONDER (Wide-ranging ONline Data for EpidemiologicResearch) database. WONDER is a computerized information system that provides on-lineaccess to epidemiologic and public health data sets. Those data are not site-specific, they arereported at the county level. Because the information is not community specific, it does notprovide the data necessary to adequately draw conclusions concerning health issues as they relateto the site.
Riggin's Mortality Tapes
Riggin's Mortality Tapes provide information on deaths by county, state, and the U.S.; it does notprovide site-specific information. Because the information is not specific for the community ofconcern, it does not provide the data necessary to adequately draw conclusions concerning healthissues as they relate to the community.
Oklahoma is currently designing a tumor registry. Once the registry begins collectinginformation, several years of data collection will be necessary before the registry may be used fordetermining if and where high cancer rates exist.
Following are health concerns the community has raised and ATSDR's response:
|1.||How extensive and harmful is the contamination of the Garber-Wellington aquifer? What about future water use?|
To ensure no future impact on drinking water sources, Tinker has installed a series of monitoringwells. Tinker has 66 monitoring wells in the northeast quadrant of the base that are sampled onan annual basis. These wells have been sampled annually since 1992. Twelve well clusters (36wells) have been installed under the existing off-base investigation. These new wells are in thevicinity of off-base private wells. Samples from these additional wells will be representative ofgroundwater contamination in the area. Sampling of these wells began in early 1995.
ATSDR recommends that people not use private well water in the Kimsey Addition or the areanear the intersection of Douglas Boulevard and S.E. 29th Street (areas 1 and 2 on Figure 4b).
|2.||How safe are the drinking water supplies?|
The other drinking water source is groundwater. Community (well serves several homes, i.e.,trailer park well) and private wells are located in neighborhoods near Tinker. Some wells havebeen found to be contaminated while others are currently free of chemical contamination. However, the potential does exist for contaminants to migrate to those wells locateddowngradient from the several potential sources of contamination. Therefore, we recommendthat the water from private and community wells in the Kimsey Addition, Evergreen Trailer Park,and neighborhoods near the intersection of 29th Street and Douglas Boulevard not be used forany purpose.
Groundwater is also used by the base for drinking water (base supply wells). Contamination hasbeen detected in two wells near Building 3001. These wells were immediately taken out ofservice. The wells that are currently in use are monitored according to the Safe Drinking WaterAct.
|3.|| Is the drinking water in Building 3001 and coffee made with it safe to consume?|
|4.|| Is our well water safe for laundry and showering -- it has black particles in it and is greasy?|
The black particles and the greasy film on the water may be a result of high mineral content ofthe water. The water in the Tinker area has a high mineral content and is considered hard water. Hard water often forms scaly deposits on the inner surfaces of cooking utensils and pipes thatcarry hot water. Mineral salts in hard water can precipitate the fatty acids from soap (i.e., laundrydetergents and bath soap) in the form of a scum or jelly-like particles.106
|5.||Could washing a convenience store parking lot with well water cause rashes and sores on legs?|
The rashes and sores may be a result of exposure to spilled gasoline. Appropriate protectiveclothing and knee length boots should be worn while washing down parking lots to protectworkers from splashed gasoline.
|6.||Could past exposures to contaminated groundwater cause heart defects or chronic diarrhea in my daughter? |
Short-term exposures to trichloroethylene (TCE) and 1,2-DCA at high concentrations have beenassociated with irregular heartbeats (cardiac arrhythmias). For example, the use of TCE as ananesthetic (i.e., concentrated TCE) has been linked with cardiac arrhythmias. However, based onthe data provided to ATSDR, the concentrations of VOCs detected in the wells around Tinker aremuch lower and exposure is not expected to cause cardiac arrhythmias.
Although fetuses in the first three months of pregnancy may be especially sensitive to TCE, theconcentrations of TCE detected at Tinker (5.2-13.8 ppb) are much less than the concentrationsassociated with birth defects. Epidemiologic studies have found an association between pregnantwomen's chronic exposure to TCE-contaminated drinking water and congenital heart defects intheir children.83 However, these studies were concerned with exposures of 6-239 ppb; thus, theupper limit of exposure in these studies is much higher than the exposure at Tinker. Further, thesignificance of this finding is questionable because of the possibility that the women wereexposed to multiple chemicals, so it is not possible to be sure that the birth defects were notcaused by one of the other chemicals or by all the chemicals together.
Although 1,2-dichloroethane, TCE, and antimony can cause diarrhea, they are not expected tocause it at the concentrations detected in private wells. Thus, based on the information reviewedby ATSDR, it is not likely that diarrhea or heart defects could result from past exposures tocontaminated groundwater.
|7.||I live near the base. Is my fetus safe from groundwater contamination?|
|8.||Is there an unusually high cancer rate in the communities surrounding Tinker?|
Evaluation of data in this public health assessment determined that an increase in cancer risk isunlikely from exposures to current ambient air emissions from the IWTP or from exposures tocontaminated private well water.
|9.||Could lupus be related to base contamination?|
Systemic lupus erythematosus is a chronic multisystem inflammatory disorder. In lupus, theimmune system forms antibodies to the body's own tissue and attacks the organs and bodysystems. The exact cause of lupus is unknown. However, certain drugs and chemicals caninduce a lupus-like syndrome.107 The chemicals associated with lupus can be divided into fourclasses: aromatic amines, hydrazines, sulfur containing drugs, and the hydralazine anti-convulsants.
|10.||How can the volatilization of jet fuel from fuel spills affect our health?|
Jet fuels are composed of a complex mixture of hydrocarbons (benzene, toluene, xylenes, andPAHs). Because jet fuel is a mixture of several components, limited toxicity information isavailable on their combined health effects.
The association between jet fuel and cancer was evaluated by the International Agency forResearch on Cancer Working Group on the Evaluation of Carcinogenic Risks to Humans. TheWorking Group concluded that there is insufficient evidence to determine that jet fuel causescancer in animals or humans.108
|11.|| Can children wading in Soldier Creek develop chloracne? |
The Oklahoma City/County Health Department maintains a log of complaints by residents. Complaints about children developing skin irritations/rashes after wading in Soldier Creek areincluded in the log. Citizens can report complaints and have them included in the log by callingthe Oklahoma City/County Health Department.
|12.|| Is it unsafe for children to play in or around Soldier Creek due to the environmental contamination?|
|13.||Two children developed skin irritations after playing in East Soldier Creek downstream of the IWTP last August (1993). Could chemicals from Tinker have caused their skin irritations?|
The IWTP is required to report any discharge above its NPDES permit limit. We reviewed allthese reports from September 1988 through January 1994. No violations were determined to beof public health concern.
Three violations of water quality standards occurred during August 1993: 1) on 1 August 93 thechemical oxygen demand was 1248 lbs/day versus the permit limit of 1126 lbs/day; 2) on 3August 93 biochemical oxygen demand was 24 mg/L versus the permit limit of 15 mg/L; and 3)on 24 August 93 the total suspended solids was 56 mg/L versus the permit limit of 50 mg/L. Skin irritations (rashes) would not be expected from exposure to the water in East Soldierfollowing these types of violations.
|14.||When wastewater from the base overflows into Crutcho and Soldier Creeks, can contaminants that are harmful enter these water systems?|
Treated sanitary and industrial wastewaters are discharged into East Soldier Creek. Occasionally, during periods of heavy rainfall the final clarifiers of the wastewater treatmentplant will overflow. This would result in the effluent being higher in suspended solids thandesired. However, the overflow is further treated by going through a final filtration stage. Dataare not available on the quality of the treated water during one of these rain events.
|15.||Are the fish caught in Soldier Creek safe to eat?|
One environmental concern is that metals can bioconcentrate in fish tissue. The metalscadmium, beryllium, antimony, chromium, and manganese were detected in Soldier Creeksediments at levels above soil comparison values. The metals chromium, manganese, cadmium,and arsenic were detected in Soldier Creek surface waters at levels above drinking watercomparison values. However, the concentrations were relatively low and were not a healthconcern for people who have come into contact with creek water or sediments. Although thesemetals can bioconcentrate in fish, it is unlikely that at the concentrations detected in the creekthey would pose a health concern for fish consumption.
|16.||Is it possible that contaminants have entered yards adjacent to Soldier Creek and would garden vegetables from those yards be harmful if consumed?|
It is possible that contaminants could bioaccumulate if contaminated water from the creek is usedto water yards and gardens. However, levels of contamination detected in Soldier Creek surfacewater are not expected to result in contaminant concentrations in vegetables that would be ofpublic health concern.
|17.||Our garden vegetables and plants have black, oily particles on them? What could it be and is it safe?|
ATSDR recommends that the fruits and vegetables be thoroughly washed and peeled, if possible,to remove the substance before preparing the food.
|18.||Is the air safe in the vicinity of the IWTP?|
ATSDR concluded that emissions of hydrogen sulfide were at concentrations that may beperceived as a nuisance to the community. ATSDR recommended that the Air Force develop anon-going air monitoring program at the IWTP. The Air Force has developed such a program andhas begun implementation of the program.
|19.|| I live adjacent to the base and experience sinus problems and a tight chest periodically. Could this be caused by air pollution and contaminated water from the IWTP?|
People could be exposed to contaminants that evaporate from the wastewater while it is held intanks at the IWTP prior to treatment. However, ATSDR issued a health consultation in March1994 that concluded that current emissions from the IWTP were not a health concern for childrenor adults in the nearby residential area or for workers at the IWTP.
|20.||I live adjacent to the base and have experienced dermal reactions such as dry and itchy scalp, rashes, open sores, and skin growths. Could this be caused by air pollution and contaminated water from the IWTP?|
Phenols were detected in the air in the vicinity of the IWTP during the initial investigations ofambient air at the IWTP. Although the association between skin irritation (dermatitis) andexposure to airborne phenol has not been established, it is suspected that dermatitis is associatedwith exposure to phenol.109
Phenol was detected at 140 ppb in May of 1993, a concentration above the Oklahoma MaximumAmbient Air Concentration of 100 ppb. After the base reviewed their records, it determined thatthe peak occurred during a time of unusually high use of phenol in an industrial process atTinker. The Air Force is monitoring the use of phenol to avoid these short-term peaks. ATSDR's review of the phenol influent to the IWTP from January 1993 through February 1994showed that May 1993 was the only period when the phenol was unusually elevated duringnormal industrial activity.
Treated wastewater from the IWTP is discharged to East Soldier Creek. During the remedialinvestigation, no contamination was detected in the surface water or sediments of the creek thatwas of public health concern.
|21.||Will children enrolled at the Childhood Development Center be safe from contamination?|
|22.||Is it safe for employees to work near the hazardous waste sites? |
Current air emissions at the IWTP were determined as no apparent health hazard for workers. On May 31, 1995, air samples were collected at the Chemical Cleaning Subunit in Building3001.111 The samples were analyzed for TCE. TCE was not detected above the detection limitof 0.28 mg/m3. The TLV is 269 mg/m3.
ATSDR is only authorized to address worker safety as it relates to the hazardous waste sites onbase. Worker safety concerns about normal operations should be referred to the OccupationalSafety and Health Administration who regulates worker safety for current work procedures.
|23.||Is it safe to hunt? Is the wildlife safe to consume?|
There is no evidence that the on-base fishing pond is contaminated.