PUBLIC HEALTH ASSESSMENT
MEMPHIS DEFENSE DEPOT (DEFENSE LOGISTICS AGENCY)
(a/k/a USA DEFENSE DEPOT MEMPHIS)
MEMPHIS, SHELBY COUNTY, TENNESSEE
APPENDIX A: PARAMETERS TESTED IN THE SCREENING, 1989 AND 1995-1998 REMEDIAL, BACKGROUND, AND BRAC SAMPLING PROGRAMS(23)
1-methyl naphthalene |
chromium, dissolved chrysene cis-1,3-dichloropropene cobalt cobalt, dissolved copper copper, dissolved dalapon DDD DDE DDT decachlorobiphenyl - ss delta BHC di-n-butyl phthalate di-n-octylphthalate dibenz(a,h)anthracene dibenzofuran dibromochloromethane dibromofluoromethane dicamba dichloroprop dieldrin diethyl phthalate dimethyl phthalate dinoseb endosulfan II endosulfan sulfate endosulfan I endrin ketone endrin aldehyde endrin ethyl benzene fluoranthene fluorene fluoride, free fluorobenzene gamma BHC (lindane) gamma-chlordane heptachlor heptachlor epoxide hexachlorobenzene hexachlorobutadiene hexachlorocyclopentadiene hexachloroethane indeno(1,2,3-cd)pyrene iron iron, dissolved isophorone lead lead, dissolved magnesium magnesium, dissolved manganese manganese, dissolved MCPP mercury mercury, dissolved methoxychlor methyl isobutyl ketone methyl ethyl ketone (2-butanone) methylene chloride n-nitrosodiphenylamine n-nitroso-di-n-propylamine naphthalene nickel, dissolved nickel nitrobenzene octachlorodibenzo-p-dioxin octachlorodibenzofuran PCB, total PCB-1016 (arochlor 1016) PCB-1221 (arochlor 1221) PCB-1232 (arochlor 1232) PCB-1242 (arochlor 1242) PCB-1248 (arochlor 1248) PCB-1254 (arochlor 1254) PCB-1260 (arochlor 1260) pentachlorophenol petroleum hydrocarbons pH phenanthrene phenol potassium, dissolved potassium pyrene selenium selenium, dissolved silver silver, dissolved silvex (2,4,5-TP) sodium, dissolved sodium styrene TCDD equivalence terphenyl-d14 tert-butyl methyl ether tetrachloro-m-xylene - ss tetrachloroethylene (PCE) thallium thallium, dissolved toluene total PAHs total xylenes total fuel hydrocarbon, gasoline total 1,2-dichloroethene total organic carbon (soil/water) toxaphene trans-1,3-dichloropropene trichloroethylene (TCE) vanadium, dissolved vanadium zinc zinc, dissolved |
APPENDIX B: EXPLANATION OF EVALUATION PROCESS
In evaluating these data, ATSDR used comparison values to determine which chemicals to examine more closely. Comparison values are health-based thresholds below which no known or anticipated adverse human health effects occur. Comparison values can be based on cancer or non-cancer health effects. Non-cancer levels are based on the lowest (i.e., most toxic) valid toxicologic study for a chemical and the assumption that a small child (22 lbs.) is exposed every day. Cancer levels are the media concentrations at which there would be a one in a million excess cancer risk for an adult eating contaminated soil every day for 70 years. For chemicals for which both cancer and non-cancer numbers exist, the more toxic (i.e., lower) level is used. A description of the comparison values used in this evaluation can be found in Appendix C. Exceeding a comparison value does not mean that health effects will occur, just that more evaluation is needed.
Further evaluation focuses on identifying which chemicals and exposure situations are likely to be a health hazard. The first step is the calculation of child and adult exposure doses, as described in Appendix D. These are then compared with an appropriate health guideline for a chemical. An exposure dose is the amount of chemical ingested daily per unit of body weight. Health guidelines are the amount of chemical per unit of body weight where health effects very likely do not occur, based on investigations of human exposures to the chemical, or, if human data don't exist or are not valid, of animal experiments. Most health guidelines are based on animal data. The results of these calculations are presented in Tables D1 and D2 starting on page 71. Any exposure situation, where the exposure dose is lower than a health guideline, is eliminated from further evaluation.
The next step in the evaluation process is determining whether the worst case exposure situations used in earlier calculations need to be revised to better fit the actual situation. For example, both Dunn Field and the DDMT Main Facility have reportedly been fenced and guarded since the Depot opened. Except for the area near the 8 base housing units, small children could not have experienced health effects due to exposure to contaminants on-site because they could not enter the site. Thus, exposure situations involving small children (1-2 years old) were dropped from further evaluation except for those that include the base housing area on Main Facility. Likewise, exposure situations for adults on Dunn Field would assume that exposure is less frequent than for adults on the Main Facility because it appears that no one spent every work day on Dunn Field.
The last evaluation step is the comparison of these revised exposure doses with known toxicological values for the chemical of concern. This would include the no observed and lowest observed adverse health effects levels (NOAEL & LOAEL) identified in ATSDR Toxicological Profiles. If the chemical of concern is a carcinogen, the cancer risk is recalculated using the revised exposure dose. These comparisons are the basis for stating whether the exposure might be a health hazard.
APPENDIX C: EXPLANATION OF COMPARISON VALUES
Health Comparison Values
Health Comparison Values (CVs) are the contaminant concentrations found in a specific media (air, soil, or water) and used to select contaminants for further evaluation. The CVs used in this document are listed below.
Environmental Media Evaluation Guides (EMEGs) are estimated contaminant concentrations in a media where no chance exists for non-carcinogenic health effects to occur. The EMEG is derived from U.S. Agency for Toxic Substances and Disease Registry's (ATSDR) minimal risk level (MRL).
Remedial Media Evaluation Guides (RMEGs) are estimated contaminant concentrations in a media where no chance exists for non-carcinogenic health effects to occur. The RMEG is derived from U.S. Environmental Protection Agency's (EPA) reference dose (RfD).
Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations that would be expected to cause no more than one additional excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors (CSF).
Risk-Based Concentrations (RBCs) are the estimated contaminant concentrations in which no chance exists for carcinogenic or noncarcinogenic health effects. The RBCs used in this public health assessment were derived using provisional reference doses or cancer slope factors calculated by toxicologists of EPA's Region III (101).
EPA Action Levels (EPA ALs) are the estimated contaminant concentrations in water of which additional evaluation is needed to determine whether action is required to eliminate or reduce exposure. Action levels can be based on mathematical models.
EPA Soil Screening Levels (EPA SSL) are estimated contaminant concentrations in soil at which additional evaluation is needed to determine if action is required to eliminate or reduce exposure.
APPENDIX D: CALCULATION OF ESTIMATED EXPOSURE DOSES
Calculation of Exposure Dose from Ingestion of Contaminated Soil
The exposure doses for ingestion of contaminated soil were calculated in the following manner. The maximum or mean concentration for a chemical in DDMT soil was multiplied by the soil ingestion rate for adults, 0.0001 Kg/day, or the rate for children, 0.0002 Kg/day. This product was divided by the average weight for an adult, 70 Kg (154 pounds), or for a small child, 10 Kg (22 pounds). For adults, we assumed that only DDMT workers could have been exposed. Thus, exposure could have occurred 5 times a week rather than 7, which resulted in the exposure dose being adjusted by a factor of 5/7ths (0.7). Exposure doses for children were calculated. However, it is unlikely that children, especially small children, could have been exposed except for that area around the eight units of Base Housing on eastern edge of the Main Facility. Regular exposure of children on the rest of the DDMT Main Facility and Dunn Field would not have occurred because they have always been fenced and guarded. Those calculations assume frequent daily exposure to soil contaminated at the specified level. The results of the actual calculations are recorded in Tables D1 - D2 on the following pages.
Calculation of Risk of Carcinogenic Effects
Carcinogenic risks from the ingestion of soil were calculated using the following procedure. The adult exposure doses for ingestion of soil were calculated as described previously, then multiplied by the EPA's Cancer Slope Factor (CSF) for that chemical (102). This result was multiplied by 0.4 because maximum exposure length of 30 years was assumed rather than the 70 years assumed for the CSF. This is because we concluded that only workers could be exposed. Results of the calculation of carcinogenic risk from exposure can be found on Tables D1 and D2 on the following pages.
The actual risk of cancer is probably lower than the calculated number. The method used to calculate EPA's Cancer Slope Factor assumes that high dose animal data can be used to estimate the risk for low dose exposures in humans (103). The method also assumes that there is no safe level for exposure (104). Little experimental evidence exists to confirm or refute those two assumptions. Lastly, the method computes the 95% upper bound for the risk, rather than the average risk, which results in there being a very good chance that the risk is actually lower, perhaps several orders of magnitude (105). One order of magnitude is 10 times greater or lower than the original number, two orders of magnitude are 100 times, and three orders are 1,000 times.
Table D1. Estimated Exposure Doses and Cancer Risk for Dunn Field Soil Contaminants Compared to Health Guidelines for Ingestion 1
Contaminant | Maximum Level in parts per million (ppm) | Estimated Child Exposure Doses in mg/kg/day* | Estimated Adult Exposure Doses in mg/kg/day* | Health Guideline in mg/kg/day* | Source of Guideline | Cancer Risk |
Alpha-chlordane | 1.5 | 0.00003 | 0.000002 | 0.0003 | MRL2 | 1 in 1,000,0003 |
Arsenic | 43.7 | 0.0009 | 0.00006 | 0.0003 | MRL2 | 9 in 100,0004 |
Benzo(a)pyrene | 68 | 0.001 | 0.00007 | none | none | 2 in 10,0005 |
Beryllium | 1.3 | 0.00002 | 0.000002 | 0.002 | RfD6 | 7 in 1,000,0003 |
Dieldrin | 4.8 | 0.0001 | 0.000001 | 0.00005 | MRL2 | 1 in 10,0003 |
Iron | 36,400 | 0.7 | 0.05 | 0.1 | EPA-PV7 | not a carcinogen |
* mg/kg/day = milligrams/kilogram/day
1 An explanation of how these exposure doses and cancer risk were calculated can be found in the preceding page. No health guidelines are available for iron, lead, benzo(a)anthracene, benzo(b)fluoranthene, indeno(1,2,3-c,d)pyrene, benzo(k)fluoranthene, and dibenz(a,h)anthracene. 2 MRL = ATSDR's minimal risk level. For more information on the MRL for arsenic or alpha- chlordane, see the arsenic or chlordane toxicological profiles. 3 Maximum additional lifetime risk of cancer per 1,000,000 individuals. 4 Maximum additional lifetime risk of cancer per 100,000 individuals. 5 Maximum additional lifetime risk of cancer per 10,000 individuals. 6 RfD = EPA's reference dose. For more information on the RfD for beryllium, see EPA's IRIS database. 7 EPA-PV = EPA's provisional reference dose for EPA region III risk-based concentration table. Go to http://www.epa.gov/reg3hwmd/risk/riskmenu.htm . |
Table D2. Estimated Exposure Doses and Cancer Risk for
Soil Contaminants Compared to Health Guidelines for Ingestion 1
Contaminant Level | Level in Parts per Million (ppm) | Estimated Child Exposure Doses in mg/kg/day* | Estimated Adult Exposure Doses in mg/kg/day* | Health Guideline in mg/kg/day* | Source of Guideline | Cancer Risk |
Maximum Arsenic | 84 | 0.002 | 0.0001 | 0.0003 | MRL2 | 2 in 10,0003 |
Mean Arsenic | 15.7 | 0.0003 | 0.00002 | 0.0003 | MRL2 | 3 in 100,004 |
Maximum Benzo(a)Pyrene | 450 | 0.009 | 0.00007 | none | none | 5 in 1,0005 |
Mean Benzo(a)Pyrene | 6.6 | 0.0001 | 0.000009 | none | none | 7 in 100,004 |
Maximum Dieldrin | 10 | 0.0002 | 0.00001 | 0.00005 | MRL2 | 2 in 100,0004 |
Mean Dieldrin | 0.5 | 0.00001 | 0.0000007 | 0.00005 | MRL2 | 1 in 1,000,0007 |
Maximum DDT | 59 | 0.001 | 0.00008 | 0.0005 | RfD6 | 3 in 100,0004 |
Mean DDT | 0.8 | 0.00002 | 0.0000008 | 0.0005 | RfD6 | 0.4 in 1,000,0007 |
Maximum Iron | 242,000 | 4.8 | 0.3 | 0.1 | EPA-PV8 | not a carcinogen |
Mean Iron | 23,409 | 0.5 | 0.03 | 0.1 | EPA-PV8 | not a carcinogen |
* mg/kg/day = milligrams/kilogram/day
1 An explanation of how these exposure doses and cancer risk were calculated can be found in the preceding pages. No health guidelines are available for lead, benzo(a)anthracene, benzo(b)fluoranthene, indeno(1,2,3-c,d)pyrene, and dibenz(a,h)anthracene. 2 MRL = ATSDR's minimal risk level. 3 Maximum additional lifetime risk of cancer per 10,000 individuals. 4 Maximum additional lifetime risk of cancer per 100,000 individuals. 5 Maximum additional lifetime risk of cancer per 1,000 individuals. 6 RfD = EPA's reference dose. 7 Maximum additional lifetime risk of cancer per 1,000,000 individuals. 8 EPA-PV = EPA's provisional reference dose for EPA region III risk-based concentration table. Go to http://www.epa.gov/reg3hwmd/risk/riskmenu.htm . |
APPENDIX E: CONTAMINANT TABLES FOR THE DEFENSE DEPOT - MEMPHIS, TENNESSEE
Table E1. Contaminants in Dunn Field Sediment above Comparison Value*
Contaminant | Range in Sediment in mg/kg1 | Dunn Field Mean in mg/kg | DDMT Area Mean in mg/kg | Samples > DL2 | Samples >CV3 | CV in mg/kg | CV Source4 |
Arsenic | 1.7 - 14.1 | 5.2 | 4.7 | 16/16 | 16/0 | 0.5/20 | CREG/EMEG |
Benzo(a)anthracene | 0.07 - 5.4 | 0.9 | 0.9 | 16/16 | 5 | 0.9 | EPA SSL |
Benzo(a)pyrene | ND - 5.9 | 1.0 | 0.9 | 15/16 | 11 | 0.1 | CREG |
Benzo(b)fluoranthene | 0.1 - 4.9 | 1.5 | 0.9 | 16/16 | 9 | 0.9 | EPA SSL |
Beryllium | ND - 1.2 | 0.8 | 0.2 | 12/16 | 12/05 | 0.2/3006 | CREG/RMEG |
Dibenz(a,h)anthracene | ND - 0.5 | 0.2 | 0.8 | 9/16 | 8 | 0.09 | EPA SSL |
Dieldrin | ND - 0.3 | 0.07 | 0.008 | 14/16 | 9/0 | 0.04/3 | CREG/EMEG |
Indeno(1,2,3-c,d)pyrene | ND - 5.1 | 0.8 | 0.8 | 13/16 | 4 | 0.9 | EPA SSL |
* The source of these data is the 1990 RI
(3), and the 1995, 1998, and 1999 sediment sampling data provided directly
to ATSDR by DDMT. There is a legend for this table following Table E7. |
Table E2. Contaminants in Dunn Field Surface Water above
Comparison Value *
Contaminant | Range in Water in mg/L7 | Samples > DL2 | Samples > CV3 | CV in mg/L** | CV Source4 |
Arsenic | ND - 0.01 | 4/7 | 4/0 | 0.002/0.3 | CREG/EMEG |
* The source of these data is the 1990 RI
(3), and the 1995, 1998, and 1999 sediment sampling data provided directly
to ATSDR by DDMT. ** These comparison values are multiplied by 100 because it is assumed that daily ingestion of surface water for a small child is 10 milliliters (ml) rather than the 1 liter (1,000 ml) used for drinking tap water. There is a legend for this table following Table E7. |
Table E3. Surface Soil Contaminants above a Comparison
Value
Contaminant | Range in mg/kg1 | Samples > DL2 | Samples > CV3 | CV in mg/kg | CV Source4 |
Alpha-chlordane | ND - 4 | 50/243 | 5/15 | 0.5/36 | CREG/RMEG |
Antimony | ND - 2,420 | 114/323 | 8 | 20 | RMEG |
Arsenic | ND - 101 | 352/361 | 351/705 | 0.5/206 | CREG/EMEG |
Barium | 6 - 7,300 | 158/158 | 3 | 4000 | RMEG |
Benzo(a)anthracene | ND - 970 | 167/352 | 59 | 0.9 | EPA SSL |
Benzo(a)pyrene | ND - 450 | 164/349 | 121 | 0.1 | CREG |
Benzo(b)fluoranthene | ND - 540 | 174/359 | 59 | 0.9 | EPA SSL |
Benzo(k)fluoranthene | ND - 450 | 151/338 | 23 | 9 | EPA SSL |
Beta BHC | ND - 2.5 | 11/168 | 2 | 0.4 | CREG |
Bis(2-ethylhexyl) phthalate | ND - 250 | 45/110 | 1/05 | 50/1,0006 | CREG/RMEG |
Cadmium | ND - 159 | 187/347 | 6 | 10 | EMEG |
Chlordane | ND - 1.2 | 9/66 | 1/05 | 0.5/306 | CREG/EMEG |
Chromium | 5 - 16,200 | 370/370 | 17 | 300 | RMEG |
Chrysene | ND - 620 | 178/357 | 2 | 88 | EPA SSL |
Copper | ND - 28,500 | 370/372 | 2 | 3,100 | HEAST |
DDD | ND - 3.6 | 116/316 | 1 | 3 | CREG |
DDE | ND - 39 | 187/333 | 9 | 2 | CREG |
DDT | ND - 59 | 205/334 | 15/15 | 2/306 | CREG/RMEG |
Dibenz(a,h)anthracene | ND - 160 | 21/334 | 15 | 0.09 | EPA SSL |
Dieldrin | ND - 10 | 180/324 | 125/95 | 0.04/36 | CREG/EMEG |
Gamma-chlordane | ND - 4 | 60/310 | 7/05 | 0.5/306 | CREG/EMEG |
Heptachlor | ND - 1.1 | 3/159 | 1/05 | 0.2/306 | CREG/RMEG |
Heptachlor epoxide | ND - 0.3 | 4/161 | 2/05 | 0.08/0.76 | CREG/EMEG |
Indeno(1,2,3-c,d)pyrene | ND - 310 | 132/302 | 48 | 0.9 | EPA SSL |
Iron | 1,360 - 242,000 | 108/108 | 18 | 23,000 | HEAST |
Lead | ND - 17,500 | 371/372 | 42 | 400 | EPA SSL |
PCB-1254 (Arochlor 1254) | ND - 10 | 2/114 | 1 | 1 | RMEG |
PCB-1260 (Arochlor 1260) | ND - 18 | 11/166 | 7 | 0.4 | CREG |
Thallium | ND - 42 | 3/222 | 1 | 5.5 | HEAST |
Zinc | 9 - 28,200 | 378/378 | 3 | 20,000 | EMEG |
Table E4. Contaminants in Sediment Samples above a Comparison
Value
Contaminant | Range in mg/kg1 | Samples > DL2 | Samples >CV3 | CV in mg/kg | CV Source4 |
Arsenic | ND - 14 | 25/37 | 25/05 | 0.5/206 | CREG/EMEG |
Antimony | ND - 56.7 | 4/37 | 1 | 20 | RMEG |
Benzo(a)anthracene | ND - 2.1 | 22/37 | 5 | 0.9 | EPA SSL |
Benzo(b)fluoranthene | ND - 2.3 | 24/37 | 5 | 0.9 | EPA SSL |
Benzo(k)fluoranthene | ND - 25 | 21/37 | 1 | 9 | EPA SSL |
Benzo(a)pyrene | ND - 2 | 24/37 | 18 | 0.1 | CREG |
Beryllium | ND - 0.6 | 31/39 | 19/05 | 0.2/3006 | CREG/RMEG |
Cadmium | ND - 168 | 14/37 | 1 | 10 | EMEG |
Chromium | 9 - 3,400 | 37/37 | 1 | 300 | RMEG |
DDT | ND - 2.9 | 16/37 | 1/05 | 2/306 | CREG/RMEG |
Dibenz(a,h)anthracene | ND - 0.3 | 4/37 | 2 | 0.09 | EPA SSL |
Gamma-chlordane | ND - 0.7 | 7/18 | 1/05 | 0.5/306 | CREG/EMEG |
Iron | ND - 49,300 | 19/29 | 1 | 23,000 | HEAST |
Lead | ND - 7,640 | 31/37 | 2 | 400 | EPA SSL |
Total polynuclear aromatic hydrocarbons | ND - 16.5 | 7/11 | 4 | 0.1 | CREG* |
* This is the CREG for benzo(a)pyrene. There is a legend for this table after Table E7. |
Table E5. Contaminants in Surface Water above a Comparison
Value
Contaminant | Range in Water in mg/L7 | Samples > DL2 | Samples > CV3 | CV in mg/L* | CV Source4 |
Arsenic | ND - 0.08 | 24/43 | 24/05 | 0.002/0.36 | CREG/EMEG |
Dieldrin | ND - 0.0004 | 18/51 | 2/05 | 0.0002/0.056 | CREG/EMEG |
* These comparison values are multiplied by
100 because it is assumed that daily ingestion of surface water for a small
child is 10 milliliters (ml) rather than the 1 liter (1,000 ml) used for
drinking tap water. The legend for this table follows Table E7. |
Table E6. Contaminants in Background Sediment above a Comparison
Value
Contaminant | Range in Sediment (mg/kg)1 | Samples > DL2 | Samples > CV3 | CV in mg/kg | CV Source4 |
Arsenic | ND - 11.1 | 18/22 | 18/05 | 0.5/206 | CREG/EMEG |
Beryllium | ND - 0.8 | 6/22 | 6/05 | 0.2/3006 | CREG/RMEG |
Benzo(a)pyrene | ND - 2.5 | 7/22 | 3 | 0.1 | CREG |
Benzo(b)fluoranthene | ND - 2.6 | 7/22 | 2 | 0.9 | EPA SSL |
Benzo(a)anthracene | ND - 2.9 | 6/22 | 2 | 0.9 | EPA SSL |
Dibenz(a,h)anthracene | ND - 0.7 | 2/22 | 2 | 0.09 | EPA SSL |
Iron | 3,330 - 30,700 | 22/22 | 1 | 23,000 | HEAST |
Indeno(1,2,3-c,d)pyrene | ND - 1.7 | 7/22 | 1 | 0.9 | EPA SSL |
Alpha-chlordane | ND - 2.4 | 5/22 | 1/05 | 0.5/36 | CREG/RMEG |
Gamma-chlordane | ND - 2 | 5/22 | 1/05 | 0.5/306 | CREG/EMEG |
Cadmium | ND - 38 | 4/22 | 1 | 10 | EMEG |
Heptachlor Epoxide | 0.2 | 1/22 | 1/05 | 0.08/0.76 | CREG/EMEG |
The legend for this table can
be found after Table E7.
|
Table E7. Contaminants in Background Surface Water above
a Comparison Value
Contaminant | Range in Surface Water (mg/L)7 | Samples > DL2 | Samples > CV3 | CV in mg/L* | CV Source4 |
Arsenic | ND - 0.01 | 13/22 | 13/05 | 0.002/0.36 | CREG/EMEG |
*
Comparison values for drinking water were multiplied by 100 because it
was assumed that daily ingestion of surface water for a child was 10 ml
rather than the 1,000 ml used for drinking tap water.
The legend for this table can be found after this table. |
Footnotes for Tables E1 - E7
1 - mg/kg = milligrams of chemical per kilogram
of soil. mg/kg = parts per million (ppm)
2 - DL = detection limit
3 - CV = comparison value. See Appendix C for an explanation
of comparison values.
4 - These comparison values are described in Appendix
C starting on page 68.
5 - The samples above a CREG are the first number and
those above an EMEG or RMEG is the second.
6 - The first number is a CREG and the second is an EMEG
or RMEG.
7 - mg/l = milligrams of chemical per liter of water.
APPENDIX F. TOXICOLOGICAL EVALUATION
This appendix is a detailed chemical-by-chemical evaluation of the possible health consequences of exposure to DDMT contaminants. These evaluations are summarized on pages 18 and 19.
Possible Health Consequences of Chemicals found on Dunn Field
When a sample concentration exceeded a CV, the maximum level of that chemical was used to calculate an exposure dose, which was then compared with an appropriate health guideline.
Soil Contaminants
Of the 12 chemicals in soil with concentrations above CVs, five - arsenic, alpha-chlordane, beryllium, dieldrin and iron, had health guidelines for non-carcinogenic health effects. There were health guidelines to identify cancer risk for arsenic, alpha-chlordane, benzo(a)pyrene, beryllium, and dieldrin (69,88,106,107,109). Table D1 on page 71 contains the results for these five chemicals. A qualitative evaluation of the possibility of health consequences was done for the seven chemicals (benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, dibenz(a,h)anthracene, indeno(1,2,3-c,d)pyrene, iron, and lead) for which there were no health guidelines.
Arsenic
Health effects due to exposure to arsenic are not likely to occur. As indicated on Table D1, the adult exposure dose for the maximum concentration is lower than the health guideline for arsenic. The child exposure dose for the maximum level is greater than the health guideline. Additional evaluation indicates that health effects would be very unlikely because the exposure dose is about the same as the no observed adverse effects level for arsenic of 0.0008 mg/kg/day but is 15 times lower than the lowest observed adverse effects level of 0.014 mg/kg/day. In addition, regular exposure of young children to Dunn Field soil was and is extremely unlikely because Dunn Field has always been fenced, making access difficult. The risk of cancer due to exposure to arsenic is not significant even if workers were assumed to be exposed 5 days a week for 30 years.
Alpha-chlordane
Health effects due to alpha-chlordane are not likely to occur. As indicated on Table D1, the child and adult exposure doses for the maximum concentrations found in extensive sampling of Dunn Field are below the health guidelines for alpha-chlordane. The risk of cancer due to exposure to alpha-chlordane is not significant even if workers were assumed to be exposed 5 days a week for 30 years.
Beryllium
Health effects due to beryllium are not likely to occur. As indicated on Table D1, the child and adult exposure doses for the maximum concentrations found in extensive sampling of Dunn Field are below the health guidelines for beryllium. The risk of cancer due to exposure to beryllium is not significant even if workers were assumed to be exposed 5 days a week for 30 years.
Dieldrin
Health effects due to dieldrin are not likely to occur. As indicated on Table D1, the adult exposure dose for the maximum concentration is lower than the health guideline for dieldrin. The child exposure dose for the maximum level is greater than the health guideline. Additional evaluation indicates that health effects would be very unlikely because the exposure dose of 0.0001 is about 45 times lower than the no observed adverse effects level for dieldrin of 0.0045 mg/kg/day. The exposure dose is also 450 times lower than the lowest observed adverse effects level of 0.045 mg/kg/day. In addition, regular exposure of young children to Dunn Field soil was and is extremely unlikely because Dunn Field has always been fenced, making access difficult. The risk of cancer due to exposure to dieldrin is not significant even if workers were assumed to be exposed 5 days a week for 30 years.
PAHs
Six of the substances in Dunn Field soil found above comparison values are members of the chemical group, polycyclic aromatic hydrocarbons [PAHs] (69). These six are benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, dibenz(a,h)anthracene, and indeno(1,2,3-c,d)pyrene. EPA's guidance for the quantitative risk assessment of PAHs was used to identify maximum cancer risk for the 6 PAHs (108). This was done because the other 5 PAHs do not have health guidelines. The additional maximum excess cancer risk for each of the six PAHs is moderate (about 1-2 in 10,000) if someone was exposed 5 days a week for 30 years. The cumulative maximum excess risk for same length of exposure to all six PAHs is elevated (1 in 1,000).
However, although cancer risk is elevated, the actual chance of anyone being harmed is very low or non-existent because regular long-term exposure of any individual was unlikely. This conclusion is based on that fact that all PAH concentrations above background from Dunn Field came from one location. The PAH levels at the other 65 locations were 8.2 PPM or lower and are within the PAH levels of 0.2 - 61 ppm typically found in urban soil (69). The one sampling location with elevated concentrations was an area where petroleum products, food, or other materials were burned (3). PAHs are produced when such materials are burned (69). This area contaminated with PAHs would be a problem only if someone regularly worked at that spot. This appears unlikely (3,5).
Iron
Health effects due to exposure to iron are not likely to occur. As indicated on Table D1, the adult exposure dose for the maximum concentration is lower than the health guideline for iron. While the child exposure dose for the maximum level is greater than the health guideline, regular exposure of young children to Dunn Field soil was and is extremely unlikely. This is because Dunn Field has always been fenced, making access difficult.
Lead
Health effects due to exposure to lead are not likely to occur because regular exposure of young children to Dunn Field soil was and is extremely unlikely. This is because Dunn Field has always been fenced, making access difficult. A review of the ATSDR Toxicological Profile for Lead indicates that none of the lead levels identified on Dunn Field are great enough to cause health effects in adults (90).
Sediment Contaminants
Health effects due to the contaminants in Dunn Field sediment are very unlikely, even if exposure was daily. Daily exposure to contaminated sediment appears unlikely. As indicated on Table E2, the average levels of arsenic, beryllium and PAHs from the 16 locations sampled are similar to the means identified in the background sampling of the DDMT area. In addition, the PAH concentrations are within the levels of 0.2 - 61 ppm typically found in urban soil (69).
The eight chemicals in Dunn Field sediment above comparison values were arsenic, beryllium, benzo(a)anthracene, benzo(b)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, dieldrin, and indeno(1,2,3-c,d)pyrene. Of these eight, arsenic, beryllium, and dieldrin had health guidelines for non-carcinogenic health effects. The highest concentration for arsenic was 1.5 times lower than its health guideline, for beryllium it was 250 times lower, and for dieldrin it was 10 times lower (88,107,109).
Health guidelines exist to identify cancer risk for arsenic, benzo(a)pyrene, beryllium, and dieldrin (69,88,107,109). EPA's guidance for the quantitative risk assessment of PAHs was used to identify maximum cancer risk for the 5 PAHs (108). This was done because the other 4 PAHs do not have health guidelines. The risk of cancer from daily exposure to Dunn Field sediment is not significant as it ranged from 3 in 100,000 for arsenic to 6 in 1,000,000 for benzo(a)pyrene. Daily exposure has and is not occurring because no one worked on Dunn Field on a regular basis and because children could not access the area because it is fenced.
Possible Health Consequences of Chemicals found on DDMT Main Facility
When a sample concentration exceeded a CV, the maximum level of that chemical was used to calculate an exposure dose, which was then compared was an appropriate health guideline.
Soil Contaminants
Of the top 10 chemicals in soil with concentrations above CVs, four (arsenic, beryllium, dieldrin, and DDT) had health guidelines for non-carcinogenic health effects. Health guidelines exist to identify cancer risk for arsenic, benzo(a)pyrene, beryllium, dieldrin, and DDT (69,88,109,110). Table E2 on page 72 contains the results for these 5 chemicals for adult exposure doses. Exposure doses for small children were also calculated because they could have been exposed if they lived in the base housing which is located near the southeast corner of the Main Facility. Access of small children living around the DDMT Main Facility to on-site contaminants appears very unlikely because the Main Facility is and, reportedly, has always been fenced. A qualitative evaluation of the possibility of health consequences was done for the 5 chemicals [benzo(a)anthracene, benzo(b)fluoranthene, dibenz(a,h)anthracene, indeno(1,2,3-c,d)pyrene, and lead] for which no health guidelines exists.
Arsenic
Health effects due to arsenic in on-site soil samples are not likely to occur. The adult exposure doses for the maximum (84 ppm) and mean (15.7 ppm) arsenic concentrations are below the health guideline for non-carcinogenic health effects. The child exposure dose for the maximum arsenic level was above the arsenic health guideline, and for the mean level was below. In Figure G1, the 30 locations are identified where arsenic concentrations are above 20 ppm. Concentrations above 20 ppm result in a child exposure dose that exceeds the health guideline if exposure were all day every day. However, none of these locations appear close enough to base housing for small children to be regularly exposed. The cancer risk for the maximum arsenic level is low and not elevated for the mean level.
Dieldrin
Health effects due to dieldrin in on-site soil samples are not likely to occur. The adult exposure doses for the maximum and mean dieldrin concentrations are below the health guideline for non-carcinogenic health effects. The child exposure dose for the maximum dieldrin level was above its health guideline, and for the mean level, it was below. In Figure G2, the 9 locations are identified where the dieldrin concentration is above 3 ppm. Above 3 ppm results in exceeding the child comparison value if exposure is all day every day. Only one location appears close enough to base housing for daily exposure to be likely. However, the dieldrin level at that spot (5.5 ppm) does not represent a public health hazard. The exposure dose for this level (0.0001 mg/kg/day) is 45 times lower than the no observed adverse health effects level [NOAEL] and 450 times lower than the lowest observed adverse health effects level [LOAEL] seen in the lowest valid animal study (107). No valid human investigation has been done. The cancer risk for the maximum and mean levels is not elevated.
DDT
Health effects due to DDT in on-site soil samples are not likely to occur. The locations were DDT was sampled for are identified on Figure G3. The adult exposure doses for the maximum and mean DDT concentrations are below the health guideline for non-carcinogenic health effects. The child exposure dose for the maximum DDT level of 59 ppm was above its health guideline, but not any other concentration. However, this DDT level does not represent a public health hazard. The exposure dose for this level (0.001 mg/kg/day) is 50 times lower than the NOAEL and 250 times lower than the LOAEL seen in the lowest valid animal study (110). No valid human investigation has been done. The cancer risk for the maximum and mean levels is not elevated.
Iron
Health effects due to exposure to iron are not likely to occur. While, as indicated on Table D2, the adult exposure dose for the maximum concentration is higher than the health guideline for iron, it above the guideline at only two of the 108 locations sampled. It is unlikely that workers would have sufficient contact with the soil at either of these two locations to ingest enough soil to result in harm. In addition, even if there was sufficient contact, the concentrations do not appear high enough to result in health effects given the wide margin of safety between the health guideline and where health effects actually appear to occur.
Health effects due to exposure to iron by small children are unlikely due to the lack of opportunity for exposure. Child exposure doses for the maximum and mean levels are greater than the health guideline. However, regular exposure of young children to soil was and is extremely unlikely because the Main Facility has always been fenced, making access difficult.
Lead
A review of the ATSDR Toxicological Profile for Lead indicates that daily exposure to lead at the locations identified on Figure G4 where lead levels were above 400 ppm, could be a health hazard for children less than 6 years old (90). However, small children probably could not have had enough exposure to result in health effects because none of the locations with lead levels greater than 400 ppm are near the base housing units. Base housing appears to be the only location where small children could regularly contact soil on DDMT. All but 2 of the locations with lead concentrations above 400 ppm are located on the west or north side of DDMT. The 2 locations on the same side of the facility (east) as base housing are about 600 feet away. A child under 6 could not likely travel to these two locations frequently enough to result in harm.
PAHs
Five of the top 10 substances found above comparison values are members of the chemical group, polycyclic aromatic hydrocarbons [PAHs] (69). These 5 are benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, dibenz(a,h)anthracene, and indeno(1,2,3-c,d)pyrene. EPA's guidance for the quantitative risk assessment of PAHs wasused to identify maximum cancer risk for the 5 PAHs (108). This was done because the other 4 PAHs do not have health guidelines. The additional maximum excess cancer risk for each of the 5 PAHs was low (1 in 10,000) to elevated (5 in 1,000) for the maximum levels but was not elevated for the mean levels if someone were exposed 5 days a week for 30 years. The cumulative additional excess risk for exposure to the maximum concentrations of all 5 PAHs is elevated (7 in 1,000).
However, further evaluation of this exposure situation and the carcinogenicity of PAHs indicates that it is unlikely that anyone was harmed by exposure to PAHs at DDMT. Regarding the exposure situation, the elevated PAH levels are focused around the west side of Building 629, the south side of Building 249 and between Buildings 689 and 690. However, as displayed on Figure G5, the nine locations with levels above 10 ppm near Buildings 249, 629, 689, and 690 are surrounded by 61 sampling locations with much lower levels including many non-detects. The mean level for these 61 locations is about 1 ppm which represents a maximum excess cancer risk from long-time exposure of 1 in 100,000. This lower risk is probably more representative of what a worker might experience if he or she had direct daily contact (e.g., touched or dug in the dirt) with the contaminated soil.
However, it appears that few, if any, workers had direct contact with the contaminated soil based on descriptions of the operations that took place in these buildings and the make-up of the areas around the buildings. The work operations at these buildings took place inside the buildings (11). This means that most of a worker's contact with the contaminated soil would be walking over it, not working in it. In addition, it appears that workers would have little opportunity to actually contact contaminated soil even when they were outside. Nearly all the areas around these buildings were either covered with asphalt or gravel (11).
Besides the lack of sufficient exposure to PAH-contaminated soil, the uncertainty about whether exposure to PAHs in soil would actually result in cancer in humans further supports the conclusion that it is unlikely that anyone was harmed by PAHs at DDMT. Coal tars, which have PAHs as their major constituent, are identified as human carcinogens by the U.S. Public Health Service, EPA, and other agencies (69). However, the evidence on coal tars being carcinogenic indicates that cancer is caused through long-term contact with skin and not through ingestion or other routes of exposure. Animal studies support this observation. Since the possible exposures at DDMT were ingestion of PAH-contaminated soil, it is unlikely that these exposures, even if they did occur, could have resulted in cancer.
Risk of cancer does not appear to be elevated for the rest of the DDMT Main Facility because PAH concentrations are considerably lower (see Figure G6). In addition, the PAH levels found at most of the rest of the Main Facility sampling locations are within the PAH levels of 0.2 - 61 ppm typically found in urban soil (69).
Sediment
The 15 chemicals in on-site sediment samples with concentrations above a CV (Table E4), do not currently present a public health hazard. These 15 are arsenic, antimony, benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, beryllium, cadmium, chromium, dibenz(a,h)anthracene, DDT, gamma-chlordane, iron, lead, and total polynuclear aromatic hydrocarbons (PAHs). All the samples with concentrations above CVs, except for gamma-chlordane, were taken from Lake Danielson or the golf course pond. Figures G7 and G8 (pages 93 and 94) display the contaminant levels for arsenic and dieldrin. The sampling locations for the other 13 contaminants are the same as for these 2 chemicals.
It is not plausible that anyone could have been exposed on a regular basis to the sediments in the lake or pond as they would have to ingest the sediment. Indirect exposure to sediment contaminants through ingestion of fish from Lake Danielson or the golf course pond may have occurred before 1986 when fishing was banned because elevated levels of DDT, dieldrin, chlordane, and chlorpyrifos were found in sediment and fish tissue samples (3). The single sample of gamma-chlordane above the CV was found in the drainage for the western side of the Main Facility. For anyone to have regular exposure to sediment from any of these locations does not appear to be plausible because there appears to have been no facility operations at these locations (50).
Surface Water
The chemicals in the on-site surface water samples with concentrations above CVs (Table E5), do not present public health hazards because the risk of cancer and other effects is not significant. Two chemicals, arsenic and dieldrin, were above CVs (Figures G9 & G10). The maximum levels of arsenic and dieldrin are well below the noncarcinogenic health effects comparison values and the additional lifetime cancer risk from exposure to them is not significant (2 in 1,000,000 to 4 in 100,000).
Note:
The 10 maps in this appendix display the sampling locations and concentrations
for the top contaminants at DDMT. These were arsenic, benzo(a)pyrene, dieldrin,
DDT, lead, and PAHs in soil; arsenic and benzo(a)pyrene in sediment; and arsenic
and dieldrin in surface water. The concentration ranges displayed on these maps
are based on the comparison values for each contaminant. The contaminant data
displayed on these maps came from electronic files provided by DDMT through
the Corps of Engineers and their contractor, CH2MHILL. The latitudes and longitudes
for nearly all the sampling locations were also provided electronically to ATSDR
by CH2MHILL. Some sampling locations for the 1990 RI were estimated by ATSDR
using Figure 2-1 in the 1990 RI (3). The streets, creeks, and railroads displayed
on the maps in this appendix come from the TIGER files generated by the U.S.
Census Bureau. The locations of the open drainage ditches and the DDMT site
boundaries were estimated by ATSDR using Figure 3-1 from 1990 RI and Drawings
1 & 2 from the 1995 Generic RI/FS Workplan (3,79).
Figure G5. Benzo(a)pyrene Levels and Possible Worker Exposures
Figure G6. Benzo(a)pyrene in Soil
Figure G7. Arsenic Sediment Level on the Memphis Depot
Figure G8. Benzo(a)pyrene Sediment Levels on the Memphis Depot
Figure G9. Arsenic in Surface Water
Figure G10. Dieldrin in Surface Water
APPENDIX H. ANALYSIS OF SURFACE WATER PATHWAY
Evaluation of Surface Water Drainage around DDMT(24)
(1) Water on the southeast side of the Main Facility flows through concrete-lined ditches to four discharge points near the southeast corner [56]. The water then flows into 4 shallow unlined ditches off-site. These ditches eventually combine and discharge into Nonconnah Creek to the west of the airport. One of these 4 ditches flows through a neighborhood (Muller Road) between Ball and Ketchum Roads [58]. ATSDR staff have observed children playing in this ditch [57].
(2) On the westside of the Main Facility, water flows through pipes and ditches to a discharge point midway between the north and south ends of the Main Facility [56]. This water flows west through the neighborhood west of DDMT in the Tarrent Branch, which is now a lined ditch but earlier was a natural intermittent stream. This branch eventually runs into Nonconnah Creek near the junction of I-240 and I-55.
As displayed on Figure 5, drainage plans for DDMT from 1953 and 1960 identify a second open ditch coming off the west side of DDMT between Tarrent Branch and Dunn Avenue (74,73). This ditch was not displayed on a 1982 map, so it appears that sometime between 1960 and 1982, the on-site drainage was altered so that the water that once left the site in this ditch, was rerouted to Tarrent Branch (7).
(3) Drainage from all of Dunn Field, except the northeast corner, flows to the west side of Dunn Field and exits at three points [56]. Water at the northern most of these points flows in a shallow unlined ditch through that portion of Rozelle Street to the west of Dunn Field. This ditch then discharges into a lined ditch that runs east and west at the south end of this isolated segment of Rozelle Street. This lined ditch also receives the water from several industrial discharge points before it runs by the end of Rozelle Street.
After leaving the Rozelle area, this ditch goes into a pipe, then goes under the Illinois Central railroad line, and then goes northwest [58]. This pipe discharges into Cane Creek between Hamilton High and the Elvis Presley Blvd. Bridge, just downstream from the high school. Therefore, water from the Dunn Field/Rozelle area apparently does not currently flow under Hamilton High. However, long-term residents indicate that an open ditch used to carry water from Dunn Field to Cane Creek so people living in this area could have had contact with water from Dunn Field.
(4) Water from the northeast corner of Dunn Field drains into 2 lined ditches that cross Dunn Field [56]. These ditches drain at least some of the neighborhood south of Person and Hayes. These 2 ditches join before leaving Dunn Field. Another discharge point drains the north end of Dunn Field (Figure 5). These 3 ditches run into Cane Creek north of the Ragan Street Bridge and upstream of Hamilton High School. Thus, water from the northeast corner of Dunn Field does flow under Hamilton High School.
(5) Water from the northern side of the Main Facility moves off-site in a lined ditch at Dunn and Custer Streets or in storm sewers [3,56]. The ditch at Dunn and Custer switches from a lined ditch to a pipe and back to a lined ditch before flowing into a large-lined ditch that runs southeast to northwest to the northeast of the Main Facility [56]. This large ditch flows into Cane Creek to the north of the Ragan Street Bridge [3]. The storm sewers appear to flow directly into Nonconnah Creek [3]. Thus, some of the water from the northern side of the DDMT Main Facility does flow under Hamilton High School, but the rest goes directly to Nonconnah Creek.
(6) Water from the central east portion of the Main Facility, which is the area around the DDMT Administration Building, leaves the site in storm sewers which appear to discharge into Nonconnah Creek [3,5]. Thus, water from around the administration building does not flow under Hamilton High School.
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