PUBLIC HEALTH ASSESSMENT
LAKE CITY ARMY AMMUNITION PLANT
[(a/k/a LAKE CITY ARMY AMMUNITION PLANT (NORTHWEST LAGOON)]
INDEPENDENCE, JACKSON COUNTY, MISSOURI
APPENDIX A. LIST OF COMPARISON VALUES
Comparison values represent media-specific contaminant concentrations that are used to select contaminants for further evaluation to determine the possibility of adverse public health effects. The conclusion that a contaminant exceeds the comparison value does not mean that it will cause adverse health effects.
Cancer Risk Evaluation Guides (CREGs)
CREGS are estimated contaminant concentrations that would be expected
to cause no more than one excess cancer in a million (10-6) persons
exposed over their lifetime. ATSDR's CREGs are calculated from EPA's cancer
potency factors (CPFs).
Maximum Contaminant Level (MCL)
The MCL is the drinking water standard established by EPA. It is the
maximum permissible level of a contaminant in water that is delivered to the
free-flowing outlet. MCLs are considered protective of public health over a
lifetime (70 years) for individuals consuming 2 liters of water per day.
Environmental Media Evaluation Guides (EMEGs)
EMEGs are based on ATSDR minimal risk levels (MRLs) that consider body
weight and ingestion rates. An EMEG is an estimate of daily human exposure to
a chemical (in mg/kg/day) that is likely to be without noncarcinogenic health
effects over a specified duration of exposure to include acute, intermediate,
and chronic exposures.
Reference Media Evaluation Guides (RMEGs)
ATSDR derives RMEGs from EPA's oral reference doses. The RMEG represents
the concentration in water or soil at which daily human exposure is unlikely
to result in adverse noncarcinogenic effects.
APPENDIX C. ESTIMATED EXPOSURE AND HEALTH EFFECTS
Estimates of Human Exposure Doses and Determination of Health Effects
Deriving Exposures Doses
The Agency for Toxic Substances and Disease Registry (ATSDR) typically evaluates the public health implications of exposure by considering the contaminant's chemical class, concentration of the contaminants to which people may have been exposed, and how often and how long exposure to these contaminants occurred. Together, these factors help influence the individual's response to chemical exposure and potential noncancer and cancer outcomes. ATSDR estimated the human exposure doses from ingestion of water containing volatile organic compounds (VOCs) from the supply wells at LCAAP and from off-site private wells north of LCAAP. In the absence of complete exposure-specific information, ATSDR applied several conservative exposure assumptions to define site-specific exposures as accurately as possible for workers and visitors to the plant, the small number of adults and children living at the housing area, and individuals who drink water from off-site private wells.
Evaluating Potential Health Hazards
The estimated exposure doses are used to evaluate potential noncancer and cancer effects associated with chemicals of concern. When evaluating noncancer effects, ATSDR uses standard toxicity values, including ATSDR's minimal risk levels (MRLs) and EPA's reference doses (RfDs) to determine whether adverse effects are likely to occur. The chronic MRLs and RfDs are estimates of daily human exposure to a substance that are unlikely to result in adverse noncancer effects over a specified duration. To be very protective of human health, MRLs and RfDs have built in "uncertainty" or "safety" factors that make them much lower than levels at which health effects have been observed. Therefore, if an exposure dose is much higher than the MRL or RfD, it does not necessarily follow that adverse health effects will occur.
When evaluating cancer effects, ATSDR sometimes uses cancer potency factors (CPFs) that define the relationship between oral exposure doses and the increased likelihood of developing cancer over a lifetime. The CPFs are developed using data from animal or human studies and often require extrapolation from high exposure doses administered in animal studies to the lower exposure levels typical of human exposure to environmental contaminants. CPFs represent the upper-bound estimate of the probability of developing cancer at a defined level of exposure; therefore, they tend to be very conservative (i.e., overestimate the actual risk) in order to account for a number of uncertainties in the data used in the extrapolation. ATSDR estimated the potential for cancer to occur using the following equation (The estimated exposure doses and CPF values for the contaminants of concern are incorporated into the equation):
Lifetime Cancer Risk = Estimated exposure dose (mg/kg/day) x CPF (mg/kg/day)-1
Although no risk of cancer is considered acceptable, it is impossible to achieve a zero cancer risk. Consequently, ATSDR often uses a range of 10-4 to 10-6 estimated lifetime cancer risk (or 1 new case in 10,000 to 1,000,000 exposed persons), based on conservative assumptions about exposure, to determine the likelihood of excess cancer resulting from this exposure.
In addition to estimating the likelihood of noncancer and cancer effects, ATSDR reviewed the literature to evaluate possible health effects associated with exposure at the doses/concentrations estimated for the pathway described below.
Estimated Exposure Dose for Consumption of VOCs in Drinking Water
In estimating to what extent people might be exposed to VOCs, ATSDR used the following equation and applied "conservative" or safe assumptions about possible human exposure. ATSDR assumed that a person drank the most contaminated well water. ATSDR also used conservative assumptions about how often people drink water and how much they drink. These assumptions allow ATSDR to estimate the highest possible exposure dose and determine the corresponding health effects. Although ATSDR expects that few individuals, if any, were exposed to the highest levels of contamination, the "conservative" estimates are used to protect public health. The following describes the equation and assumptions used to estimate the exposure:
where:
Conc.: Maximum concentration of VOCs in the well water (ppb) CF: Conversion factor to convert ppb to parts per million (1/1,000) IR: Ingestion rate: adult=2 liters per day; child=1 liter per day EF: Exposure frequency or number of exposure events per year of exposure: 7 days/week x 52 weeks/year ED: Exposure duration or the duration over which exposure occurs: adult=30 years; child=6 years BW: Body weight: adult=70 kg (154 pounds); child=10 kg (22 pounds) AT: Averaging time or the period over which cumulative exposures are averaged (6 or 30 years x 365 days/year for noncancer effects or 70 years for cancer)
The estimated exposure doses are expected to be very conservative values because they are based on the following assumptions.
Past Exposures from the On-Site Drinking Water Supply at LCAAP
VOCs in four supply wells (17-AA, 17-FF [no longer used for drinking water], 17-K, and 17-P) at LCAAP exceeded ATSDR's health-based comparison values (CVs) for drinking water in the past. To determine whether past exposure to these contaminants in the plant's drinking water supply may have caused adverse health effects, ATSDR estimated exposure doses for people consuming water containing the highest measured concentrations detected in the wells. The estimated exposure doses were then used to evaluate potential noncancer and cancer outcomes.
Noncancer: ATSDR estimated exposure doses from ingestion of water from the LCAAP supply wells containing trichloroethylene (TCE), tetrachloroethylene (PCE), 1,2-dichloroethene, and vinyl chloride (see Table C-1). No chronic (365 days and longer) oral MRL or RfD is currently available for TCE. ATSDR also recently withdrew the intermediate (15-364 days) MRL for TCE. The study on which the intermediate MRL was based has been questioned because it contains certain flaws and limitations (e.g., the exact amount of TCE-contaminated water consumed by laboratory animals in the study is uncertain) (ATSDR 1997c).
In the absence of health-based guidelines, ATSDR reviewed the available toxicological literature to determine possible adverse effects associated with exposure at doses estimated for this pathway. On the basis of this review, the exposure doses estimated for TCE by ATSDR are several orders of magnitude lower than the lowest doses reported in the toxicological literature capable of producing noncancer effects in animals administered oral doses of TCE (ATSDR 1997c). Therefore, drinking water containing the highest detected levels of TCE reported in on-site supply wells at LCAAP is not likely to result in adverse noncancer effects.
The resulting estimated exposure dose for PCE (adults and children) and the exposure dose for 1,2-DCE (adults) are lower than their RfD. Exposures to these two chemicals at the levels detected should not be associated with adverse health effects. The exposure dose for 1,2-DCE for children is slightly higher than its RfD of 0.02 mg/kg/day, but the slightly higher dose is not of health consequence because the exposure doses estimated for 1,2-DCE by ATSDR are several orders of magnitude lower than the lowest doses reported in the toxicological literature capable of producing noncancer effects in animals administered oral doses of 1,2-DCE.
The estimated exposure dose for vinyl chloride, for both adults and children, is higher than its MRL of 0.00002 mg/kg/day. A review of the literature shows that the lowest dose of vinyl chloride in which noncancer effects were observed involved a chronic exposure animal study. This study found slight changes in cellular structure after animals were fed 0.02 mg/kg/day of polyvinylchloride powder for approximately 3 years. For most other studies, the lowest observed adverse effect level (LOAEL) was two orders of magnitude (i.e., 2.0 mg/kg/day) greater than the 0.02 mg/kg/day dose (ATSDR 1997d). Using the most conservative assumptions, the maximum estimated dose for a child was 0.03 mg/kg/day, which is in the range of the LOAEL reviewed in the literature.
Although the estimated dose for vinyl chloride (adult and child) exceeded ATSDR's MRL, it is unlikely that individuals who consumed the drinking water from LCAAP were exposed to harmful levels of this contaminant. The estimated doses of vinyl chloride were based on the maximum concentration detected (270 ppb) in one supply well, but it is not expected that anyone drank water containing that concentration. (The average level of vinyl chloride from this supply well was much lower [125 ppb] (Dames & Moore 1999). This supply well was one of 13 wells used to supply LCAAP with drinking water. Vinyl chloride was only detected in three of 13 supply wells. It is also important to note that water from the 13 supply wells is mixed and blended in a large (500,000 gallon) holding tank and no one at LCAAP is drinking water from one supply well. Therefore, it is almost certain that levels of vinyl chloride and 1,2-DCE in the finished water supply would have been much lower than the maximum concentrations used to estimate doses.
In addition, ATSDR assumed that individuals at LCAAP were drinking water from LCAAP 365 days a year. However, it is unlikely that any individual obtained their drinking water exclusively from one source. According to LCAAP representatives, individuals who have lived in the on-site housing area usually only do so for a short time, perhaps 3 or 4 years. The estimated dose calculated assumed that individuals were being exposed for 30 years.
For the reasons described above, ATSDR concludes that ingestion of TCE, PCE, 1,2-DCE, and vinyl chloride, from the LCAAP water supply in the past is not expected to have resulted in adverse health effects.
Cancer: TCE and PCE have been shown to cause cancer in laboratory animals given large doses. The link between TCE and cancer in humans is uncertain, however. Available studies are inconclusive and the data are inadequate to establish a link. For screening purposes ATSDR used a previously derived CPF for TCE of 0.011 (mg/kg/day)-1 and for PCE of 0.052 (mg/kg/day)-1. The slope factors for these chemicals are under review. ATSDR derived cancer risk estimates for exposure to TCE and PCE that fall within the range (less than 10-5) considered acceptable. On the basis of these results, ATSDR concludes that ingestion of either TCE or PCE at the levels detected in the on-site well water is not likely to result in an increased risk of developing cancer (see Table C-2).
No studies were identified regarding cancer in humans following oral exposure to vinyl chloride. There currently is no CPF for vinyl chloride based on human studies, however, there is strong evidence from inhalation studies in humans and inhalation and oral studies in animals to suggest that it is a carcinogen. EPA has concluded that sufficient evidence of carcinogenicity exists in humans and has classified vinyl chloride as a Group A (human) carcinogen. A large number of studies have reported a greater than expected incidence of a rare type of cancer, angiosarcoma of the liver, among workers exposed to vinyl chloride (ATSDR 1997d). Chronic oral studies found an increase in liver angiosarcoma in animals fed 0.3 mg/kg/day (ATSDR 1997d). The maximum exposure dose estimated for an adult consuming water from LCAAP is about two orders of magnitude lower than that found to increase liver tumors in animals. Based on this information and the very conservative exposure assumptions used, ATSDR does not expect that ingestion of vinyl chloride from the LCAAP water supply would result in an increased likelihood of developing cancer.
Off-Site Private Wells
Three VOCs were detected above CVs during LCAAP's monitoring of 12 residential wells conducted from July 1988 through September 1993. Benzene (1.1 ppb), TCE (6.4 ppb), and 1,1-DCE (2 ppb) were detected at levels slightly above their CVs. With the exception of TCE, which was detected twice above its CV, the other two chemicals were only detected one time above their CVs during the entire monitoring period.
Noncancer: ATSDR estimated exposure doses from ingestion of water from the off-site private wells for benzene, TCE, and 1,1-DCE (see Table C-3). An RfD or MRL was available for 1,1-DCE, but was not available for benzene and TCE.
ATSDR's review of the literature shows that the lowest no observed adverse effect level for benzene in animal studies was 1 mg/kg/day (ATSDR 1997a). The maximum estimated exposure for benzene for a child in private wells was about four orders of magnitude lower than what was observed in any of the studies identified. The exposure doses estimated for TCE by ATSDR are five orders of magnitude lower than the lowest doses reported in the toxicological literature capable of producing noncancer effects in animals administered oral doses of TCE (ATSDR 1997c). For 1,1-DCE, the estimated dose was lower than the RfD reported in Table C-3. Based on the maximum estimated dose and a review of the toxicologic literature, ATSDR concludes that ingestion of benzene, TCE, or 1,1-DCE at the levels detected in off-site private wells is not expected to result in adverse health effects.
Cancer: ATSDR derived cancer risk estimates for exposure to benzene, 1,1-DCE, and TCE that fall within the range (less than 10-5) considered acceptable by ATSDR. ATSDR concludes that cancer effects are unlikely to be experienced as a result of drinking water drawn from the off-site wells (see Table C-4).
Source:
Agency for Toxic Substances and Disease Registry (ATSDR). 1994. Toxicological Profile for 1,1-dichloroethene. Update. May 1994.
ATSDR. 1996. Toxicological Profile for 1,2-dichloroethene. Update. August 1996.
ATSDR. 1997a. Toxicological Profile for Benzene. Update. September 1997.
ATSDR. 1997b. Toxicological Profile for Tetrachloroethylene. Update. September 1997.
ATSDR. 1997c. Toxicological Profile for Trichloroethylene. Update. September 1997.
ATSDR. 1997d. Toxicological Profile for Vinyl Chloride. Update. September 1997.
Dames & Moore. 1999. 1998 Annual Report for LCAAP Comprehensive Groundwater Monitoring Program. August 1999.
Table C-1. Estimated Exposure Doses--Noncancer Effects
Ingestion of Drinking Water at LCAAP
| Contaminant |
Maximum Detected Contaminant Concentration (ppb) |
Estimated Exposure Dose (mg/kg/day)a | Health Guideline (mg/kg/day) |
Basis for Health Guideline | |
| Adult | Child | ||||
| 1,2-Dichloroethene |
380
|
0.01 | 0.04 | 0.02 | RfD |
| Tetrachloroethylene |
1.7
|
0.00005 | 0.0002 | 0.01 | RfD |
| Trichloroethylene
|
52
|
0.001 | 0.005 | not available | ---- |
| Vinyl chloride |
270
|
0.008 | 0.03 | 0.00002 | MRL |
Conc. = Maximum contaminant concentration in on-site supply
wells (ppb).
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: adult = 2 liters per day; child
= 1 liter per day
EF = Exposure frequency or the number of exposure events
(7 days x 52 weeks or 365 days per year)
ED = Exposure duration or the duration over which exposure
occurs: adults = 30 years; child = 6 years
BW = Body weight (kg): adult = 70 kg (154 pounds); child
= 10 kg (22 pounds)
AT = Average time or the period over which cumulative
exposures are averaged (6 or 30 years x 365 days)
Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day; MRL = ATSDR's minimal risk level; RfD= EPA's reference dose.
Table C-2. Estimated Exposure Doses--Cancer Effects
Ingestion of Drinking Water at LCAAP
| Contaminant |
Maximum Contaminant Concentration (ppb) |
Estimated Exposure Dose (mg/kg/day) a | Cancer Potency Factor (mg/kg/day)-1 |
Lifetime Cancer Risk |
| Tetrachloroethylene | 1.7 | 0.00002 | 0.052b | 1 x 10 -6 |
| Trichloroethylene | 52 | 0.0006 | 0.011b | 7 x 10 -6 |
| Vinyl chloride | 270 | 0.003 | not available | ----- |
b These cancer potency factors are currently under review by EPA.
Conc. = Maximum contaminant concentration in the on-site supply
wells (ppb)
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: 2 liters per day
EF = Exposure frequency, or the number of exposure events
( 365 days per year)
ED = Exposure duration, or the duration over which exposure
occurs = 30 years
BW = Body weight (kg): 70 kg (154 pounds)
AT = Average time or the time over which cumulative exposures
are averaged (70 years x 365 days)
Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day.
Table C-3. Estimated Exposure Doses--Noncancer Effects
Ingestion of Drinking Water From Private Wells
| Contaminant |
Maximum Detected Contaminant Concentration (ppb) |
Estimated Exposure Dose (mg/kg/day)a | Health Guideline (mg/kg/day) |
Basis for Health Guideline | |
| Adult | Child | ||||
| Benzene |
1.1
|
0.00003 | 0.0001 | not available | ---- |
| 1,1-Dichloroethene |
2
|
0.00006 | 0.0002 | 0.02 | RfD |
| Trichloroethylene (TCE)
|
6.4
|
0.0002 | 0.0006 | not available | ---- |
Conc. = Maximum contaminant concentration in off-site private
wells (ppb)
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: adult = 2 liters per day; child
= 1 liter per day
EF = Exposure frequency or the number of exposure events
(365 days per year)
ED = Exposure duration or the duration over which exposure
occurs: adults = 30 years; child = 6 years
BW = Body weight (kg): adult = 70 kg (154 pounds); child
= 10 kg (22 pounds)
AT = Average time or the period over which cumulative
exposures are averaged (6 or 30 years x 365 days)
Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day.
Table C-4. Estimated Exposure Doses--Cancer Effects
Ingestion of Drinking Water From Private Wells
| Contaminant |
Maximum Contaminant Concentration (ppb) |
Estimated Exposure Dose (mg/kg/day) a | Cancer Potency Factor (mg/kg/day)-1 |
Lifetime Cancer Risk |
| Benzene |
1.1
|
0.00001 | 0.029 | 4 x 10 -7 |
| 1,1-Dichloroethene
|
2
|
0.00002 | 0.6 | 1 x 10 -5 |
| Trichloroethylene |
6.4
|
0.00008 | 0.011b | 8 x 10 -7 |
b These cancer potency factors are currently under review by EPA.
Conc. = Maximum contaminant concentration in off-site private
wells (ppb)
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: 2 liters per day
EF = Exposure frequency, or the number of exposure events
(1 event x 7 days x 52 weeks or 365 days per year)
ED = Exposure duration, or the duration over which exposure
occurs = 30 years
BW = Body weight (kg): 70 kg (154 pounds)
AT = Average time or the time over which cumulative exposures
are averaged (70 years x 365 days)
Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day.
APPENDIX D: RESPONSE TO PUBLIC COMMENTS
The Public Health Assessment (PHA) for Lake City Army Ammunition Plant (LCAAP) was available for public review and comment from October 3, 2000 through November 22, 2000. The public comment period was announced in a press release on October 4, 2000. Copies of the public health assessment were made available for review at the Mid-continent Public Library, Blue Springs, Missouri and the LCAAP information repository. The PHA was also sent to state and federal agencies for review. Upon request from LCAAP officials, ATSDR extended the public comment period until July 26, 2001 so that comments received from the July 26, 2001 public availability session could be incorporated into the final release document.
The following are responses to EPAs comments pertaining to ATSDRs Public Comment Release.
Comment 1: In general, we disagree with your conclusions regarding the prospects of public health hazards associated with past, current, or future exposures to releases of hazardous substances from the LCAAP. Regarding past exposures, we do not believe sufficient data is available to determine whether potentially negative health impacts associated with past exposures may have occurred. Further, we do not agree that conditions at the site are currently adequately controlled such that potential exposures (and associated health impacts) will likely not occur in the future. Given site conditions, in the absence of further response actions by the Army, we believe it highly possible that significant exposures to hazardous substances could occur. We also believe that land use at the LCAAP may be subject to significant changes in the short term, based on what the Army terms its' "facilities use" approach. Such changes in land use could dramatically alter the nature of potential exposures and subsequent health risks.
Response: ATSDR acknowledges EPAs difference in opinion regarding the conclusions contained in the PHA. In the process of conducting a public health assessment (PHA), ATSDR evaluates whether a completed exposure pathway has occurred in the past, is occurring currently, or is likely to occur in the future. When a completed pathway has been identified, ATSDR evaluates whether exposures are at levels that would contribute to adverse health effects. ATSDR recognizes that some hazardous contamination generated from activities at LCAAP continues to be present on site. However, ATSDR bases its public health conclusions not only on whether contamination is present, but also on whether it is likely that people will come in contact with levels of contaminants that may be harmful. Based on the available data that was provided to ATSDR, there is no evidence of past, current, or future public health hazards. ATSDR agrees that continued monitoring of groundwater plumes beneath LCAAP is necessary to make sure that off-site migration is not taking place.
Comment 2: Page 1, Summary, Paragraph 5 - We suggest you consult with the Army/LCAAP regarding the schedule for completing a ROD for the Installation-Wide OU. It may be appropriate to provide more specific information regarding the anticipated ROD date for this OU.
Response: According to information provided by LCAAP representatives, an Interim Remedial Action ROD for metals contaminated soil for the Installation-wide OU is scheduled to be signed in the Fall 2001. LCAAP is still working on a schedule for releasing a final ROD for the Installation-wide OU, which will include both remediation of non-metal contaminants in soil and groundwater.
Comment 3: Page 2, Summary, Paragraph 4 - The PHA should indicate the basis for concluding that exposures to contaminants in private wells pose no apparent past, current, or future public health threat. In the absence of continued and/or additional response actions by the Army, the prospects for exposures and health threats are quite likely in the future.
Response: In evaluating the potential for past, current, and future health effects from drinking water, ATSDR estimated the lifetime exposure dose for both an adult and a child who drink water containing the maximum concentration of the chemical detected in either on-site supply wells at LCAAP or off-site private drinking water wells located north of LCAAP. Appendix C in the PHA provides a complete description of the methods and assumptions ATSDR used to estimate exposure. As explained in Appendix C, the dose estimates calculated are based on very conservative assumptions that have built in safety factors. ATSDR recognizes that there may be some exposure to contaminants in drinking water, however, the concentrations that have been detected in off-site private wells and in the LCAAP drinking water supply wells are not at levels considered to pose a health hazard. This evaluation is based on toxicological profiles of the chemicals detected in the drinking water.
ATSDR has recommended that LCAAP resume routine monitoring of private wells north of the Area 18 and Northeast Corner OU. According to LCAAP representatives, this monitoring is scheduled to be resumed in the spring/summer 2001 (personal communication with Garth Anderson, March 5, 2001).
Comment 4: Page 2, Summary, Paragraph 5 - The PHA should indicate the basis for the conclusions presented here, to clarify the assumptions regarding possible land use at LCAAP.
Response: ATSDR concluded that on-site soil and surface water contamination did not pose a past or does not pose a current or future public health hazard because access to LCAAP is restricted and sampling has indicated that most soil and surface water contamination is generally confined to areas near the source with no evidence of migration off site. Under LCAAP's "facility use" plan, any new land use must be reviewed by LCAAP and the Operations Support Command. Any proposed reuse of land must meet existing legal agreements and conditions , including land use restrictions and institutional controls agreed upon by LCAAP.
Comment 5: Page 3, Summary, Paragraph 2 - We believe this paragraph accurately states that "...there are not data to evaluate whether contaminants released into the air were present at levels that were harmful...". Based on this statement, it is unclear how you conclude that past exposures presented minimal health threats when insufficient data is available to support this conclusion.
Response: ATSDR must often rely on limited information when evaluating past public health hazards. When activities or operations at a site are known to have resulted in some past environmental contamination (e.g., groundwater or air), ATSDR first identifies and reviews whatever historical monitoring data is available. In cases where no monitoring data is available, ATSDR collects as much information about the nature and extent of releases into the environment.
Based on correspondence with LCAAP officials, open burning activities took place at designated open burn areas, primarily in the northeastern portion of the plant, approximately once a week as long as certain weather conditions were met. Open burns were conducted under certain weather conditions to prevent or minimize smoke and air particulates from impacting off-site residents.
According to historical information from LCAAP, approximately 300 pounds of primarily propellant and wet explosive scrap were burned per week. This amount was significantly below the LCAAP permit allowing for up to 240 pounds per day or a maximum of 1,440 pounds per week. Open burning activities were significantly reduced after the explosive waste incinerator was brought up to incinerator standards in 1989. Open burning activities were no longer conducted at LCAAP after 1993.
Based on the relative infrequency of open burns, the precautionary measures taken to prevent smoke and air particulates from impacting residents, and the very small number of residences north of LCAAP, ATSDR concludes that past exposures would not likely pose a health hazard. Although monitoring data is not available for these past activities, ATSDR has based this public health conclusion on the best available information.
Comment 6: Page 5, Background, Paragraph 2 - Alliant Techsystems is the current operating contractor for the LCAAP, assuming operations from Olin in April 2000. We suggest you confer with the LCAAP to ensure accurate information in this paragraph.
Response: ATSDR has confirmed with LCAAP that Alliant Techsystems is the current operating contractor and this will be reflected in the final PHA.
Comment 7: Page 7, Background, Paragraph 2 - Suggest that the text be revised to reflect that the Remedial Investigation for the Northeast Corner OU is still in progress. Suggest that a more specific date for the Installation-Wide OU ROD be provided.
Response: ATSDR has received updated information concerning the status of the remedial investigation for the Northeast Corner OU and this will be reflected in the final PHA. According to an LCAAP representative, the release date for the Installation-Wide OU ROD is still under negotiation.
Comment 8: Page 10, QA/QC - Suggest you briefly discuss the evaluation process employed to determine the adequacy of the available data for making public health decisions.
Response: As noted in the PHA, reports that are prepared for the Comprehensive Environmental Response, Compensation, and Liability Act and the Resource Conservation and Recovery Act programs must meet specific standards for quality assurance and quality control. In addition to this, ATSDR reviews data from site-related reports and evaluates whether detection limits are set at levels that are protective of public health. ATSDR also notes any inconsistencies or problems with data collection or reporting and evaluates whether the information is adequate to be used for making public health decisions. ATSDR will make the suggested changes noted above.
Comment 9: Page 12, Conclusions - We believe insufficient information is available to determine the nature of possible past exposures/health hazards associated with groundwater at/from LCAAP.
The PHA should clarify that the presence of drinking water of acceptable quality at LCAAP is predicated on the continued operations, maintenance, and monitoring of existing water treatment operations.
The PHA should clarify that the prevention of future exposures to contaminants in groundwater beyond LCAAP boundaries is predicated on continued operations, maintenance, and monitoring of existing response actions, and the implementation of additional actions to control releases of hazardous substances at the LCAAP.
Please correct the last paragraph to indicate that contaminants are present in groundwater at the northern plant boundary at levels above (order of magnitude) that which would pose a health threat if consumed regularly. It should be clarified that this contamination has likely migrated beyond the plant boundary, but that the nature and extent of the off-plant contamination has not been completely defined. Also, please note the presence of a groundwater contaminant plume in the western part of LCAAP, which has potential to migrate off-plant.
Response: As noted above, ATSDR estimated the dose, for both an adult and a child, of chemicals detected in drinking water wells above ATSDRs CVs. ATSDR used the maximum concentration detected in supply wells at LCAAP in order to provide a worst case scenario. Appendix C in the PHA explains the assumptions used in calculating an individual's exposure dose.
ATSDR will modify the text of the PHA to include a statement that clarifies that the safety of individuals consuming drinking water at LCAAP relies on continued water treatment and routine monitoring of the drinking water supply.
In response to the last paragraph of comment # 9, the statement on page 12 of the PHA specifically refers to contaminants detected in off-site drinking water wells. Although VOCs and metals were detected in some of these wells, the concentrations were not at levels that pose a public health hazard. VOCs were detected in untreated LCAAP drinking water supply wells [17KK (TCE-3.6 ppb) and 17K (TCE-1.5 ppb)] and in monitoring wells [16-18 (1,2-Dichloroethene-10.7 ppb); TCE-13.9 ppb)] near the northern plant boundary during 1999. However, groundwater sampling of supply wells and monitoring wells near the northern boundary showed a declining trend in VOC concentrations compared to 1998 data. ATSDR will clarify that contamination has the potential to migrate beyond the plant boundary and that it is important for LCAAP to characterize the nature and extent of contamination north of LCAAP. ATSDR will also clarify that the nature and extent of the groundwater plume in the western portion of the plant should also be characterized due to the potential for it to migrate off site.
Comment 10: Page 13, Physical Characteristics - The notion of "hydrostratigraphic units" is not truly a physical feature, but one defined for purposes of modeling, primarily. It may be appropriate to edit or simplify much of this discussion.
Response: ATSDR will note in the text that hydrostratigraphic units are not actual physical hydrogeological features, but were developed to help conceptualize how groundwater flows underneath LCAAP. ATSDR will consider clarifying or simplifying any discussion in this section where appropriate.
Comment 11: Page 15, On-Site Groundwater Contamination, Paragraph 1 - The PHA should consider that results of sampling from water supply wells may not be representative of aquifer/groundwater conditions. Given the dilution that will occur in a water supply well, unlike in a groundwater monitoring well, groundwater contamination may be much more significant than the sampling results indicate.
Response: As noted previously, ATSDR identifies whether a completed exposure pathway exists. If a completed pathway is identified, ATSDR evaluates whether this exposure is likely to cause adverse health outcomes using very conservative assumptions (e.g., estimating dose using the maximum concentration detected in drinking water supply wells).
Regardless of the levels of contamination detected in groundwater or any other environmental media, it is important to emphasize that a public health hazard exists only if people come in contact with or are exposed to harmful levels of contaminants. ATSDR evaluated the potential for treated drinking water at LCAAP to contain harmful levels of chemicals. Routine monitoring of the LCAAP drinking water supply has confirmed that the treated water that is used for drinking at LCAAP meets state and federal drinking water standards. ATSDR has not identified any individuals at LCAAP that are drinking water from untreated groundwater sources and, therefore, people are not being exposed to levels of contamination that would be harmful.
Comment 12: Page 16, On-Site Groundwater Contamination, Paragraph 2 - The PHA should indicate that groundwater contamination extends to, and likely beyond, the northern boundary of the LCAAP.
Response: ATSDR will add that the nature and extent of contamination beyond the northern plant boundary has yet to be determined and it is possible that groundwater contamination has migrated off site.
Comment 13: Page 18, Off-Site Groundwater Contamination, Paragraph 1 - The PHA states, based on a personal communication, that LCAAP groundwater extraction wells prevent most off-site migration. In terms of protectiveness, there could be a significant difference between preventing most and all off-site contaminant migration. We suggest that you supplement this personal communication with evaluation of existing records or assessments which address the effectiveness of the extraction wells in containing groundwater contamination, and that you clarify what is meant by the statement that most off-site migration is prevented.
Response: Although there may be some migration of the Area 18 and Northeast Corner OU contaminant plume, according to the 1999 Annual Report for LCAAP Groundwater Monitoring Program, which presents data from 1988 through 1999, the monitoring wells located on the northern perimeter have generally shown decreasing trends in contaminant levels. For example, in Monitoring Well 16-17, TCE levels in groundwater have decreased from 57 ppb in 1996 to 13.9 ppb in 1999.
ATSDR cannot definitively say that all off-site contaminant migration has been prevented since the nature and extent of the plume needs to be further delineated. However, based on toxicological profiles of TCE and other contaminants identified in these monitoring wells, even if people were currently exposed to the maximum concentrations that are present in northern boundary monitoring wells, such exposures would not be harmful.ATSDR expects that site-related contaminants would either not be detected or detected at much lower concentrations in the closest private wells north of LCAAP. Because the plume needs to be better defined, however, ATSDR has recommended that quarterly monitoring of private wells north of LCAAP be reinstated.
Comment 14: Page 18, Off-Site Groundwater Contamination, Paragraph 2 - The PHA states, based on a personal communication, that the presence of lead and cadmium may have been an "artifact". Since the notion of the contamination being an "artifact" is interpretive and not necessarily supported by facts, we suggest you remove this statement.
Response: This statement has been removed and the paragraph has been revised.
Comment 15: Page 20, Current and Future Exposures, On-site - The PHA should clarify that the water supply (i.e. aquifer) has not necessarily met drinking water standards, but that the treated water, prior to consumption, has met drinking water standards. It is important to highlight that a continuing treatment process is required for drinking water at the LCAAP to meet protective standards.
Response: This distinction will be clarified in the text of the PHA.
Comment 16: Page 20, Current and Future Exposures, Off-site - While the operation of the groundwater extraction well at the northern LCAAP boundary may prevent further migration of contaminants in groundwater off-plant, the nature and potential impacts of contamination which may have migrated off-plant prior to the installation of the extraction well is unknown.
Response: Because of the uncertainty regarding the nature and extent of groundwater contamination north of LCAAPs Area 18 and the Northeast Corner OU, ATSDR has recommended in the PHA that quarterly monitoring of private wells be reinstated.
Comment 17: Page 22, Evaluation of the Soil Exposure Pathway, Conclusion - Remedial actions have not yet been planned or implemented which will address all areas of contamination which may pose an unacceptable risk at the LCAAP.
Response: ATSDR will confirm with LCAAP which areas of soil contamination at LCAAP have not been addressed, either through planned or past remediation or through other interim measures.
Comment 18: Page 23, Northeast Corner OU, Paragraph 1 - The PHA refers to a "final ROD for Interim Remedial Action...". We suggest you eliminate the term "final" in describing the interim action, as it may be confusing to some readers.
Response: ATSDR will edit the text accordingly.
Comment 19: Page 23, Area 18 OU - The Army has proposed, based on data collected subsequent to the Area 18 ROD, that the Area 18 ROD be amended or revised, and that the multi-phase vapor extraction system may not be effective in addressing site contaminants. EPA, the Missouri Department of Natural Resources, and the Army are currently in the process of evaluating the Army proposal regarding the Area 18 Remedial Action. Suggest that you may want to reflect some uncertainty in the status of Area 18 to reflect that VOC contamination may be more widespread than was anticipated at the time of the ROD and that the Army and regulators are considering the most appropriate manner in which to proceed.
Response: This information for the Area 18 OU will be reflected in the final release of the PHA.
Comment 20: Page 23, Installation-Wide OU - Suggest that you indicate that additional data collection and site evaluation is warranted to better define the nature and extent of contamination, and thus potential remedies, for a number of the 31 areas referenced.
Response: This suggestion will be incorporated into the final PHA.
Comment 21: Page 34, Public Health Action Plan, Actions Ongoing or Planned - In #4, we are uncertain of the nature of any formal (enforceable) land-use restrictions which have been implemented at the LCAAP as part of any CERCLA response actions. Please clarify the nature of these restrictions.
In #5, we suggest you note that monitoring of off-plant groundwater contamination, downgradient of the Area 18 extraction system is planned/necessary.
Response: According to the ROD for Remedial Action at the Area 18 OU released in February 1998, part of the selected remedy for Area 18 OU is to prohibit agricultural (e.g., cattle grazing) and other non-industrial uses. In addition, as part of the remedial measures defined in the Final ROD for interim remedial action at the Northeast Corner OU, LCAAP is to restrict on-site worker's access to contaminated soil.
Regarding the suggestion for planned action (#5). In 1992 eight groundwater monitoring wells were installed just off site to the north of the Area 18 and the Northeast Corner OU. According to data presented in the Annual Report for LCAAP Comprehensive Groundwater Monitoring Program, these monitoring wells have not contained levels of VOCs that exceed EPA's maximum contaminant levels. The following clarification will be incorporated into the final PHA: ATSDR recommends continued routine monitoring of off-site groundwater contamination, downgradient of the Area 18 extraction system. New monitoring wells should be installed off site in any locations where data gaps may be occurring.
Comment 22: Page 35, Public Health Action Plan, Recommendations - In #2, we agree that surface water sampling at LCAAP is appropriate, but suggest that regular surface water monitoring (rather than a one-time sampling event) should be conducted over a limited number of rounds, perhaps quarterly for 2-5 years (depending on results), to better evaluate possible releases of contaminants to surface water.
Response: ATSDR agrees that routine monitoring of surface water for a specified time period is appropriate and the text will be revised accordingly.
The following are ATSDRs responses to a list of questions provided by a representative of LCAAPs Restoration Advisory Board. The questions listed below are those that pertain specifically to ATSDRs Public Comment Release. Some of the questions were directed to LCAAP and responded to by LCAAP and are not listed below (the numbers in parentheses correspond to the actual number on the original list provided).
Questions submitted to ATSDR January 23, 2001.
Comment (#1): What is the actual date of the compiled information in the recent public health assessment report by the ATSDR?
Response: ATSDR relied on the most currently available information at the time of the release of the public health assessment (Public Comment Draft) to base its public health conclusions. Environmental sampling data for LCAAP was collected as part of a preliminary assessment/site investigation released in January 1989 and remedial investigations for the Installation-Wide Operable Unit (OU) (February 1994), Area 18 OU (January 1995), and the Northeast Corner OU (March 1995). The on-site drinking water supply monitoring data was obtained for 1999, which was the most recent sampling period available. The drinking water monitoring data from the City of Independence and the Missouri Department of Health were collected in1998, the most recent time periods available prior to the release of the Public Comment Draft. ATSDR will continue to evaluate new information as it becomes available and will revise its public health conclusions and recommendations accordingly.
Comment (#3): Please provide me with a map of LCAAP indicating all the areas in the ATSDR report that state access to this area is restricted.
Response: ATSDR has not identified a site map that indicates areas at LCAAP that have restricted access. However, ATSDR has corresponded with LCAAP regarding access restrictions to the plant. According to LCAAP officials, the entire plant perimeter is fenced with several gated entry points around the plant. These entry points are either locked or have a guard posted. There is no evidence that trespassing onto LCAAP property has been a problem in the past. In addition to the perimeter fence, there is an inner fence that runs along and just south of Buckner Road. This fence encompasses about two-thirds of the plant, including the entire industrial area. There is also a fence around the firing range and special permission is required to access this area. Although most of the designated areas of contamination on site are not fenced, they are contained within the plant perimeter and public access is restricted.
Comment (#6): Why is the ATSDR public health assessment report titled Northwest Lagoon which is Area #12 paint shop?
Response: This area is responsible for LCAAP being placed on EPAs National Priorities List (NPL). LCAAP was first logged into ATSDR's tracking system in reference to Area 12, as the "LCAAP Northwest Lagoon". Even though the PHA covers the entire facility, to ensure consistent record-keeping the formal title of the PHA is "Lake City Army Ammunition Plant (Northwest Lagoon).
Comment (#10): Please explain uranium metallic compounds as stated in Area #3 sand pits.
Response: In the February 1994 RI report for LCAAP it was stated that some uranium metallic compounds were reportedly disposed of by the Department of Energy's Kansas City (Bendix) operations. However, investigations at Area 3 did not identify any radiological sources. According to this report, slightly elevated beta activities compared with background in soil were detected (range = 5 - 6.4 pCi/kg) during the source characterization. Two groundwater monitoring well locations in Area #3 out of a total of 20 were found to have alpha activities that exceeded ATSDR's comparison values (CVs). The maximum alpha level detected was 41 pCi/L (CV = 15 pCi/L).
Comment (#11): Please provide complete explanation ATSDR report page #27 (evaluation of air exposure pathway)- conclusion.
Response: As stated in the Nature and Extent section of the PHA, the primary sources of air emissions from LCAAP in the past were the sealing operations units, open burning/open detonation of wet pyrotechnics and propellant powder, and the Explosives Waste Incinerator.
Sealing Operations Units -
In the past, the sealing operations units did release some VOCs and ozone depleting chemicals. These chemicals were specifically used in the case mouth waterproofing areas and primer insert operations. According to LCAAP officials, solvents used in these areas include ethyl acetate, methyl chloroform, ethyl alcohol, methyl ethyl ketone, and toluene. The sealing operations units are located in the industrial area near the center of the plant. These VOCs would not have resulted in harm to individuals who reside near LCAAP because releases were near the center of the plant, the quantities of solvents used were relatively small, and VOCs are rapidly dispersed once released into the atmosphere.Open Burning/Open Detonation -
The burning grounds were constructed in the middle 1950's. LCAAP operated the burning ground area for the open burning/open detonation of waste explosives, mixes, and powders. Burning activities were generally conducted once a week as long as specific weather conditions were met. Based on historical information, approximately 300 pounds of materials per week were burned at LCAAP. The most common materials burned were propellant and wet explosive scrap (e.g., calcium resinate, magnesium, barium peroxide, polyvinyl chloride, and propellant powder). The permitted burn rate for these wastes could not exceed 240 pounds per day, every day for a maximum of 1,440 pounds per week. Based on historical information, LCAAP was well under the permitted rates averaging about 60 pounds per day. According to LCAAP officials, open burning/open detonation activities were stopped in1993 (correspondence with Paul Anthamatten, March 2001). LCAAP did not conduct ambient air monitoring during burning activities and based on correspondence with Plant officials, no unusual burn events or incidents took place and ATSDR is not aware of any complaints from residents living near LCAAP during the time period that open burning /open detonation occurred.Explosives Waste Incinerator (EWI) -
According to LCAAP officials the EWI meets all current emissions standards and has not received any notice of violations during its period of operation. The EWI was brought up to incinerator standards in 1989. Prior to 1989, it was operated as a popping furnace to incinerate small quantities of materials.Air Pathway Public Health Hazard Determination -
Since actual air monitoring data was not available, ATSDR based its public health conclusion on historical information (e.g., types of materials, quantities, and frequency with which operations or activities occurred). ATSDR's designation of "no apparent public health hazard" recognizes that some past exposures were possible from the sealing operations units and open burning/open detonation activities, however, it is unlikely that these exposures were at levels that would pose a public health hazard.Comment (#12): The ATSDR public health assessment report is based on available information, and due to the fact that all is not known about the LCAAP site, would this report not be considered inconclusive and not construed as no "public health hazard"?
Response: When evaluating whether exposure has occurred, ATSDR considers how people might come into contact with, or be exposed to, contaminated media, and also considers the likely length (duration) and frequency of the exposure. If exposure was or is possible, ATSDR then considers whether chemicals were or are present at levels that might be harmful to people. It is important to emphasize that a public health hazard exists only if people come in contact with, or are otherwise exposed to, harmful levels of contaminated media.
ATSDR does not always have historical monitoring data to make conclusive statements regarding the potential for past exposures. However, if past monitoring data is not available, ATSDR identifies the best available information in which to base its conclusions (e.g., potential receptor populations, current monitoring data, complaints filed or other community concerns) and decides whether it is likely that public health hazards may have existed in the past, may currently exist, or are likely to exist in the future.
When there is no information or very limited information available about a specific exposure pathway at a site, ATSDR may decide that additional data needs to be collected and evaluated to determine whether a public health hazard has existed in the past or currently exists. Depending on the hazard potential of the site and the feasibility of collecting additional data, the pathway may be designated an indeterminate public health hazard. Based on correspondence with LCAAP officials and given what is known about the types and extent of chemicals used at the plant, ATSDR has concluded that the overall Public Health Hazard Category for LCAAP is "No Apparent Public Health Hazard." This classification recognizes that for certain pathways at LCAAP exposure to contaminants has occurred in the past or may be occurring at levels that are not likely to cause adverse health effects. ATSDR's assessment process is ongoing and ATSDR will reevaluate its conclusions as new information becomes available.
Comment (# 13): The ATSDR public health assessment report states several times and consequently in several areas that no public health hazard exists due to the supposed fact that access to the plant and or certain areas are restricted. However, one of the main objectives seems to be to increase the occupancy at LCAAP, therefore how can this be safely achieved?
Response: One of the recommendations made by ATSDR in the Public Health Action Plan of the LCAAP PHA (p35) is that any area(s) of the plant that is/are leased out undergo a final evaluation for environmental contaminants to meet the standards of safety and public health of the intended use. According to LCAAP officials, any designated area at LCAAP that is considered for a new use must be suitable for the type of activities that will be conducted. Any new facilities use request at LCAAP must follow a formal evaluation and approval process. Any proposed reuse of land at LCAAP must be reviewed by LCAAP and Operations Support Command. Any proposed plan must meet the existing legal agreements and conditions put forth by regulatory agencies regarding land use restrictions and institutional controls.
Comment (#14): It is stated several times in the ATSDR report pertaining to several different areas that there are no drinking water supply wells located in this area. However, what is the likelihood that these identified contaminants could leach into the water supply and or migrate from the site by other means, such as becoming airborne or surface water runoff and consequently in the water supply?
Response: ATSDR evaluates all potential exposure pathways and considers worst case exposure scenarios when evaluating whether a public health hazard exists. Environmental studies have shown that, in certain locations, the groundwater underneath LCAAP is contaminated. However, off-site monitoring wells and private well sampling data have not identified any contamination that would pose a public health hazard. A few of the off-site private wells have contained very low levels of metals and VOCs and ATSDR recommends that these wells be routinely monitored in the future to ensure that the water remains safe for drinking. Surface water has been sampled at LCAAP and there is no evidence that contamination is migrating off site at levels that would be of concern. ATSDRs evaluation of groundwater, surface water, sediment, and air exposure pathways has not identified any contamination migrating off site that would pose a public health hazard.
Comment (# 15): The ATSDR report states that for area #25, there were no tests conducted in this area due to the stated fact that this area contains predominantly asbestos related materials and access is restricted. Why were no tests conducted of this area and why is air sample monitoring not necessary?
Response: According to LCAAP officials, this landfill is covered with soil and vegetation. There is no completed air pathway since construction debris and asbestos related materials are not accessible.
Comment (#16): The ATSDR report - area #21 specifically, building 3A and 12A, were used for machining and assembly of depleted uranium (DU) and also states "no public health hazard exists." Was this area tested for DU contamination?
Response: Both of these buildings have been tested for DU. Initial inspections by the Nuclear Regulatory Commission (NRC) indicated that building 3A required some additional cleanup of radiological contamination. Specifically, the floors of the southeast wing of building 3A were found to be contaminated with DU. LCAAP has conducted additional decontamination and is waiting final inspection by NRC. Any surface areas or soil samples which do not meet the established cleanup standards will undergo further remediation as required. Cleanup activities are expected to be completed by the end of September, 2001. According to the Environmental Baseline Survey (USCHPPM), Building 12A does not require any additional clean up measures to be taken.
Comment (#17): The ATSDR report, specifically area #27A and #27B, contain DU and it was further stated that removal of the DU was to be completed by the end of 2000. Was this completed?
Response: According to LCAAP officials, the cleanup of Area 27A is scheduled to be completed by the end of September 2001. For Area 27B, the NRC has setup an agreement with the EPA to transfer regulatory oversight to the EPA CERCLA program. The firing range continues to be used by LCAAP and the area is restricted by an interior fence and only authorized personnel are allowed inside the area.
Comment (# 18): ATSDR report area #28 refers to a pipeline leak that occurred in the 1950's and that there were no indications of contamination, and yet the report also states that there are no sampling data available and that no public health hazard exists due to the age of the spill. Why were no samples taken and would this leach into a water source?
Response: During the preliminary site investigations at LCAAP, investigators attempted to identify the pipeline spill. According to correspondence with LCAAP, investigators were unable to find the spill or any residual contamination. Sampling was not deemed necessary because it was unlikely that any residual contamination would be identified in soil or groundwater samples.
Comment (# 19): Was the ATSDR public health assessment report conclusion, page #67, regarding off-site private drinking wells released in the year 2000 based only on testing that occurred between 1987 to 1993 seven years prior to the release of this report?
Response: In March 1998, the Missouri Department of Health conducted additional off-site sampling of 6 residential wells to the north of the plant (northwest quadrant). The drinking water in these wells met state and federal drinking water standards. Although LCAAP stopped the monitoring of private wells in 1993, off-site monitoring wells just north of LCAAP have not indicated that contaminants are migrating off site. ATSDR does recommend that routine private well monitoring be reinstated to ensure that drinking water continues to met safe drinking water standards. Based on this information, the hazard designation for off-site groundwater contamination was "no apparent public health hazard." ATSDR will continue to evaluate new information and modify conclusions accordingly.
Comment (# 20): ATSDR report page #70 (summary of potential pathways at LCAAP) - air - states that ambient air sampling was not conducted in the past and other than the explosives waste incinerator; site specific ambient air sampling of contaminated sites are to date still not taking place. Why? Please explain.
Response: According to LCAAP officials, open burning/open detonation no longer takes place at LCAAP. New technologies have substantially reduced or eliminated the use of solvents and ozone depleting chemicals in the sealing operations units. Besides the Explosives Waste Incinerator, which is closely monitored by LCAAP, there are no other significant air emissions occurring at LCAAP.
Comment (# 21): ATSDR report area #22 states that exposure to radioactive sources would be of very short duration. Please explain.
Response: Area # 22 is accessed infrequently by plant personnel and the amount of exposure from radionuclides in soil would be very minimal. Access to LCAAP is restricted and only visitors or the occasional trespasser may be present on site property. It is unlikely that visitors or trespassers will come in contact with Area # 22 and any exposures from infrequent contact with soil would note pose a health hazard.
Additional comments sent to ATSDR July 17, 2001
Comment 1: Based on ATSDR parameters pertaining to exposure to contaminants and of sufficient magnitude and duration for a health hazard to exist, what are or could become health hazards on or off LCAAP if one or more current safeguards at LCAAP were to fail and shouldn't this be included in the public health assessment?
Response: At present the environmental safeguards consist of access restriction, which includes a gate and security around the perimeter of LCAAP and an inner fence around the industrial area. In addition to restricting access to unauthorized individuals, other safeguard measures that have been implemented include soil removal actions at source areas of contamination and groundwater remediation such as pump-and-treatment systems and air strippers for the removal of VOCs. Failure of access restriction would only likely be in the form of a breach in fencing, which would be temporary. Levels of contamination in most source areas at LCAAP are not high enough to present a public health hazard for reasonable, short-term exposure for any scenarios which might occur. Failure of the groundwater containment system or of air strippers would be detected by monitoring systems, with repairs being initiated in a reasonably short time. Groundwater contamination levels are not high enough to present a public health hazard for short-term exposures.
Comment 2: What are the potential health hazards to the residents, employees, and community regarding any contaminants leaching into the groundwater supply due to the known fact that all contaminants exist, and to the unknown fact that all contaminants are being 100 percent contained on and off LCAAP property and in addition that the magnitude of contamination of all known areas is not completely certain and/or that all contaminanted areas conclusively have been discovered?
Response: This public health assessment describes in detail the potential exposures of the community to environmental contaminants from LCAAP. Extensive environmental studies have been conducted under the oversight of state and federal regulators. It is very unlikely that unidentified areas of contamination exist at LCAAP since preliminary assessments and site investigations have sampled suspected areas of contamination throughout LCAAP. Groundwater underneath LCAAP has been extensively monitored and the drinking water on site is closely monitored for the presence of contamination. Off- site monitoring wells to the north of the plant have thus far not detected contaminants that would pose a public health hazard to residents who obtain their drinking water from shallow or intermediate wells. ATSDR recommends that LCAAP continue quarterly off site monitoring of groundwater to ensure that it continues to meet safe drinking water standards.
Comment 3: Has and will ATSDR's public health assessment report take into consideration the various types of hazardous waste permits now in effect at LCAAP?
Response: The purpose of the ATSDR public health assessment is to evaluate the potential public health effects of hazardous chemicals in the event that they are released into the environment. Oversight of the waste permitting process is the responsibility and mission of state and federal regulators. ATSDR is confident that the oversight by these regulators of the waste permits is sufficient to assure safe handling of these materials.
Comment 4: What are the potential health hazards to the community regarding any contaminated groundwater run-off flowing into Fire Prairie Creek and consequently off LCAAP property?
Response: The potential exposures to contaminants is described in preceding sections of this PHA. Surface water sampling conducted off site has not identified any contaminants that would pose a public health hazard. As a precautionary measure, ATSDR has recommended that surface water and sediment sampling at Fire Prairie Creek be routinely sampled to ensure that surface water is not contaminated.
Comment 5: Due to the uncertainty of types, areas, and magnitude of contamination, is it responsible to make a conclusive public health assessment statement that no public health hazard exists?
Response: As described above, there have been extensive studies conducted to define the extent of contamination in the environment at LCAAP. Based on an evaluation of these studies, ATSDR has concluded that the contamination in soil, water, and air at LCAAP has not resulted in a past, current, or future public health hazard.
Comment 6: What are the potential health hazards to the residents, employees, and community in regards to various types of hazardous waste stored and/or treated at LCAAP?
Response: As discussed in #3 above, waste treatment and storage are regulated and monitored by state and federal agencies. Current hazardous waste management practices at LCAAP are closely monitored and harmful environmental releases are not expected to occur in the future. Although past releases of contaminants into the environment has occurred and monitoring of contaminants generally began during the 1980's, ATSDR's public health assessment did not identify practices or conditions at LCAAP that would have likely resulted in a public health hazard. If any future releases are of sufficient magnitude that additional public health evaluation is believed to be necessary ATSDR can conduct additional evaluations.
Comment 7: Due to the various types of contamination/hazardous waste at LCAAP, isn't it prudent to take random air samples at set intervals at various sites on and off LCAAP property?
Response: The nature and extent of releases to the air are discussed in this public health assessment. These consist of low level past releases of solvents from the sealing operations unit at LCAAP during normal operations; smoke from open burning of relatively small amounts of ordnance; and regulated and monitored normal operational emissions from the on-site incinerator. Based on discussions with plant personnel and reviews of site documents, ATSDR has concluded that these emissions were not likely harmful in the past. Additional measures to reduce VOC air emissions have been taken at LCAAP in an effort to phase out ozone depleting chemicals used in the manufacturing process. These actions have further reduced the likelihood of any potential exposures and, therefore, current and future air emissions are not expected to present a public health hazard.
Comment 8: What are or could be potential health hazards in regards to contaminants and/or stored hazardous waste pertaining to non-facility municipal firefighters or utility workers om LCAAP property?
Response: Standard operating procedures involving coordination between LCAAP and fire-fighting personnel are required by law and are monitored by OSHA. Such procedures are standard for any fire-fighting activity. OSHA also controls the activities of utility workers accessing any industrial area, including any which might contain hazardous waste.
