WELDON SPRING SITE REMEDIAL ACTION PROJECT
(CHEMICAL PLANT, RAFFINATE PITS, QUARRY)
ST. CHARLES, ST. CHARLES COUNTY, MISSOURI
APPENDIX D: GLOSSARY
| Ci | A curie (Ci) is the basic unit used to describe the intensity of radioactivity in a sample of material. The curie is equal to 37 billion disintegrations per second, which is approximately the rate of decay of 1 gram of radium. |
| CREG | Cancer Risk Evaluation Guides (CREGs) are the estimated contaminant concentrations that would result in one excess cancer in a population of a million persons exposed over a lifetime (70 years). CREGs are calculated from the U.S. Environmental Protection Agency's (EPA's) cancer slope factors. |
| Effective Dose | The sum of the products of the dose equivalent to the organ or tissue and the weighing factors applicable to each of the body organs or tissues that are irradiated. |
| EMEG | Environmental Media Evaluation Guides (EMEGs) are values used to select chemical contaminants of potential health concern. The Agency for Toxic Substances and Disease Registry calculates EMEG values using conservative exposure assumptions designed to protect the most sensitive segment of the population. |
| Gy | Gray (Gy) is the unit of absorbed dose (1 Gy = 100 radiation absorbed dose [rad] units) developed by the International System (SI) of weights and measures. |
| Ionization | Ionization is the process of adding one or more electrons to or removing one or more electrons from atoms or molecules, thereby creating ions. High temperatures, electrical discharges, or nuclear radiations can cause ionizations. |
| MCL | Maximum Contaminant Levels (MCLs) are contaminant concentrations that EPA deems protective of public health over a lifetime (70 years) at an exposure rate of 2 liters of water per day. |
| mrem | Millirem, or one-thousandth part of a Roentgen equivalent man (rem) unit. |
| mg/kg | Milligrams per kilogram, equivalent to parts per million (see below). |
| mSv | Millisievert, or one-thousandth part of a sievert. |
| µg/m3 | Microgram per cubic meter. |
| µCi | Microcurie. A microcurie is equivalent to one-thousandth of a curie |
| pica | An abnormal craving to eat substances not fit for food, as clay or paint. |
| pCi | Picocurie (pCi) is equivalent to one trillionth part of a curie. |
| Progeny | Progeny refers to isotopes formed by the radioactive decay of some other isotope. |
| R | Roentgens (R) are units used to measure exposure to ionizing radiation. A roentgen is the amount of gamma rays or X rays required to produce ions carrying one electrostatic unit of electrical charge in one cubic centimeter of dry air under standard conditions. |
| rad | Radiation absorbed dose (rad) is a unit used to measure how much radiation an object absorbs after it is exposed to radiation. |
| rem | Roentgen equivalent man (rem) is a unit used to measure the radiation effectiveness in man. It is a function of the radiation absorbed dose (rad) and the type or quality of radiation. |
| RfD | Reference doses (RfDs) are estimates of the daily exposure to a contaminant unlikely to cause adverse health effects. |
| RMEG | Reference Dose-based Media Evaluation Guide (RMEGs) are values calculated using EPA's Reference Dose (RfD) (see definition above). |
| Sv | Sievert (Sv) is the SI unit of radiation effectiveness in man. The dose equivalent in sieverts is equal to the absorbed dose in gray multiplied by the quality factor (1 Sv = 100 rem). |
PRELIMINARY PUBLIC HEALTH ASSESSMENT
Addendum to Preliminary Public Health Assessment
April 24, 1989, Health Consultation
February 10, 1993, Health Consultation
1993 Letter on Proposed Cleanup Levels
January 20, 1994, Health Consultation
August 30, 1994, Health Consultation
WELDON SPRINGS SITE
ST. CHARLES, MISSOURI
CERCLIS NO.'S
M05210021288
DECEMBER 15, 1988
*AMENDED*
M03210090004 (DOE)
M05210021288 (DOD)
THE ATSDR HEALTH ASSESSMENT: A NOTE OF EXPLANATION
Section 104 (i) (7) (A) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended, states "...the term 'health assessment' shall include preliminary assessments of potential risks to human health posed by individual sites and facilities, based on such factors as the nature and extent of contamination, the existence of potential pathways of human exposure (including ground or surface water contamination, air emissions, and food chain contamination), the size and potential susceptibility of the community within the likely pathways of exposure, the comparison of expected human exposure levels to the short-term and long-term health effects associated with identified hazardous substances and any available recommended exposure or tolerance limits for such hazardous substances, and the comparison of existing morbidity and mortality data on diseases that may be associated with the observed levels of exposure. The Administrator of ATSDR shall use appropriate data, risks assessments, risk evaluations and studies available from the Administrator of EPA."
In accordance with the CERCLA section cited, ATSDR has conducted this preliminary health assessment of the data in the site summary form. Additional health assessments may be conducted for this site as more information becomes available to ATSDR.
The conclusion and recommendations presented in this Health Assessment are the result of site specific analyses and are not to be cited or quoted for other evaluations or Health Assessments.
WELDON SPRING QUARRY
WELDON SPRING, MISSOURI
NOVEMBER 18, 1988
Prepared by:
Office of Health Assessment
Agency for Toxic Substances and Disease Registry (ATSDR)
Background
The Weldon Spring Site (WS) is listed by the U.S. Environmental Protection Agency on the National Priorities List (NPL). The 9-acre site is an abandoned limestone quarry located in Weldon Spring (St. Charles County), Missouri. WS contains approximately 95,000 cubic yards of radiological and chemically contaminated soil, rubble, debris, and equipment. Part of WS, the training area, is controlled by the U.S. Department of Defense (e.g., U.S. Army). The other portion of WS is under control of the U.S. Department of Energy. The site boundaries will be expanded to include the chemical plant and raffinate pits as part of the existing NPL site. The chemical plant was a former ordnance production facility in the late 1940's, and was used for uranium processing in the late 1960's. The raffinate pits are unlined areas used for the disposal of wastes from the production of pure uranium. These pits have been reported to contain silica, uranium, and thorium. Access to the site is restricted. Removal actions have not occurred.
The following documents were reviewed by ATSDR: (1) Radiological Report, September 1985, (2) Research Investigation of Hazardous Waste, February 1987, (3) Chemical Characterization Report, August 1987, (4) Hydrology and Water Quality Report, December 1987, (5) Water Quality Phase I Assessment, December 1987. These documents form the basis of this Preliminary Health Assessment.
Environmental Contamination and Physical Hazards
Preliminary on-site soil sampling results have identified radium-226 (1,200 pCi/g), thorium-230 (6,800 pCi/g), uranium (2,400 pCi/g and 8,350 ppm), 2,4,6 trinitrotoluene TNT) (1,600 ppm), 2,4 dinitrotoluene (DNT) (33 ppm), 2,6 DNT (68 ppm), polynuclear aromatic hydrocarbons (PAHs) (1,000 ppm), polychlorinated byphenyls (PCB's 120 ppm). In addition, uranium was identified in groundwater (8,800 pCi/L) and surface water (2,100 pCi/L).
Preliminary off-site groundwater sampling results have identified uranium (4,692 pCi/L); 2,4,6, TNT (15 to 377 ppb); 2,4 DNT (0.5 ppb); 2,6 DNT (3 ppb), and 1,3,5 trinitrobenzene (TNB) (7 ppb). In addition, uranium was detected in surface water (116 pCi/L). Physical hazards were not reported.
Potential Environmental and Human Exposure Pathways
Potential environmental pathways include contaminated groundwater, surface water, soil and sediment, and volatilization of contaminants or contaminants entrained in ambient air. In addition, bioaccumulation of contaminants in fish, water fowl, livestock, and commercial agricultural products may be another environmental pathway.
Potential human exposures to contaminants include ingestion of and direct contact with groundwater, surface water, soil, and possible ingestion of bioaccumulated contaminants in the food chain. In addition, inhalation of volatilized contaminants or contaminants entrained in air is another potential source for human exposure.
Demographics
It is unknown as to how many people live within a 2-mile radius of the site. The distance from WS to the nearest residence has been estimated to be less than 2 miles. The well field, a water source for 58,000 people, is less than a mile from WS. A high school is located approximately 3 miles from the quarry.
Evaluation and Discussion
Soil surface contamination by explosives and groundwater contamination from the quarry are extensive. There are reportedly areas of radioactive contamination in the army training area. On-site, soil concentrations of Ra-226 exceeds the limits expressed in 40 CFR 192 for uranium by-products by a factor of approximately 1,000. In addition, Radon-222 emanating from this site is assumed to exceed these limits (20 pCi/m2 per second). It is unclear if the Army currently conducts training on-site. Direct contact and possibly inhalation of potentially hazardous materials poses an imminent public health concern to soldiers training on-site. The U.S. Department of Energy (DOE) intends to collect waste materials currently in the Army training area. Moreover, DOE intends to deposit the waste materials with the other radioactive waste currently present in the raffinate pits and quarry area.
Soil sampling information confirms the presence of site-related contaminants off-site. Off-site contamination reportedly is not extensive, but off-site soil sampling information was not reported. Off-site soil sampling information is necessary to determine the extent of exposure of site-related contaminants to area residents. It was reported that on-site exposure is unlikely since the area is fenced. It was also reported that air sampling measurements were performed on-site, but air sampling information was not reported. Entrainment of contaminants in airborne dust may be a possible exposure pathway to area residents as well as persons having authorized access to the site.
Private wells in use within several miles of the site are not reported to be contaminated. The private wells in the vicinity of WS are reported to be in "a separate hydrogeological system". Sampling information confirming the absence of site-related contaminants in area private wells was not reported. Various site-related contaminants (TNT, DNT, TNB, and uranium) were identified in off-site groundwater and there have been unsubstantiated reports that the aquifer of concern may be fractured. Therefore, sampling of area private wells is necessary to rule out exposure and possible health concerns to area residents. Production wells are not contaminated. However, sampling information confirming the absence of site-related contaminants has not been supported. Municipal wells within the vicinity of WS are not contaminated. Public system data have confirmed the absence of site-related contaminants in municipal well water.
A small stream adjacent to WS is reported to be contaminated. The stream flows less than 1 mile to the Missouri River. It has been reported that contamination is migrating downstream to the Missouri, "but probably not migrating in large enough concentrations to impact the quality of the river." Surface water uranium concentrations do not exceed 10 CFR 20 values for the maximum concentration above natural background for the general public. However, surface water values are about twice that normally found in fresh water (usually no more than 70 pCi/L). Sediment sampling information was not reported and is necessary to define the extent of off-site contamination. Moreover, fishing occurs in the adjacent stream and in the Missouri River. Fish flesh sampling (e.g., edible portions) information is also needed to determine the amount of possible exposure to area residents. In addition, hunting occurs in the area and it is reported that deer, pheasant, water fowl, and rabbits are likely to be contaminated. Biota samples have been taken but the sampling results are not currently available.
Conclusions and Recommendations
Based on available information, this site is considered to be of public health concern because of the risk to human health caused by the likelihood of human exposure to hazardous substances. On-site exposure to gamma radiation poses a significant public health risk to persons having access to the site. In addition, areas directly adjacent to the site may pose serious public health concerns because of ingestion of levels of radium in either surface or groundwater. Direct contact with and incidental ingestion of contaminated soil by authorized personnel and area residents are the exposure pathways of concern. Other probable exposure pathways include inhalation of contaminants entrained in air, ingestion of bioaccumulated contaminants in the food chain, and direct contact, ingestion with, and inhalation of off-site soil and sediment. Ingestion of groundwater may also be another possible exposure pathway.
Additional information on contaminants released, populations potentially exposed, and environmental pathways through which the contaminants can reach these populations is necessary. At a minimum, future investigations of this site should include a characterization of the site and site contaminants to include air sampling measurements, area food chain sampling, and off-site soil and sediment sampling, an updated area well survey, and a characterization of the hydrogeology of the area.
Further environmental characterization and sampling of the site and impacted off-site areas
during the Remedial Investigation and Feasibility Study (RI/FS) should be designed to address
the environmental and human exposure pathways discussed above. When additional information
and data such as the completed RI/FS are available, such material will form the basis for further
assessment by ATSDR as warranted by site-specific public health issues.
March 29, 1990
Environmental Health Scientist, Emergency Response and Consultation Branch (ERCB), Division of Health Assessment and Consultation, ATSDR (E32)
Addendum to Preliminary Public Health Assessment:
David A. Parker
ATSDR Regional Services, Region VII
Through: Chief, ERCB, DHAC, ATSDR (E32) ___
Chief, RPB, DHAC, ATSDR (E32) ___
Attached is an Addendum to the Weldon Spring Health Assessment. This should satisfy your request for consultation for the above mentioned site.
Please contact me if you have any questions regarding this Addendum.
ATSDR:DHAC:ERCB:JEABRAHAM:veb:2/29/90:ext. 0615
Doc. WELDON
Weldon Spring, St. Charles County, Missouri
BACKGROUND AND STATEMENT OF ISSUES
The Weldon Spring Chemical Plant Site is listed by the U.S. Environmental Protection Agency (EPA) on the National Priorities List (NPL). The 17,000-acre site is located in Weldon Spring (St. Charles County), Missouri. A portion of the site, 1,700 acres, has been designated a training area for troops in the U.S. Army Reserve. "Approximately 1 year ago, partially in response to ATSDR's and EPA's expression of concern regarding troop training activities in potentially contaminated areas, the Army closed the Weldon Spring Training Area to troop training."
The ATSDR received a request on March 2, 1990 (through Mr. David Parker, ATSDR Regional Representative) from EPA Region VIII Superfund Remedial Branch regarding the resumption of training of U.S. Army Reserve troops on-site. The EPA would like ATSDR to address whether a health threat exists from exposure to lead and trinitrotoluene (TNT), and its related compounds on-site to Army Reservists training in the designated on-site areas.
DOCUMENTS REVIEWED
DISCUSSION
The designed training areas in question are located outside TNT production areas; moreover, based on historical use, these areas have a low probability for contamination. The Army has performed lead and TNT soil sampling within the proposed training area. A subset -- 99 samples -- of the 1,070 soil samples that were considered to be the "most highly contaminated samples" were analyzed (personal communication March 15, 1990, between Dr. Abraham and Mr. Parker, ATSDR, EPA Region VII). The soil samples from the 18 designated training areas were analyzed for 6 explosives (TNT, dinitrotoluene, nitrotoluene, trinitrobenzene, dinitrobenzene, and nitrobenzene).
Analytical results demonstrated TNT levels of less than 10 ppm in over 90 percent of 1,070 samples; however, 13 samples demonstrated TNT levels between 20 to 55 ppm. One soil sample revealed 1,000 ppm of lead; however, the area where sampling occurred is overgrown with vegetation.
The ATSDR is concerned over the possibility of radioactive contamination existing at this site. Weldon Spring Quarry, a different Operable Unit on-site, received radioactive wastes from the St. Louis Airport Storage Site, the Hazelwood Interim Storage Site, and the Futura Coatings Site. These wastes consisted of thorium and radium wastes from uranium processing in the 1940's and 1950's. The U.S. Department of Energy (DOE) only characterized areas where there was reasonable expectations of radioactive contamination. Radioactive contamination is not expected to be present in the areas designated for training according to DOE and EPA (personnel correspondence between Dr. Abraham, ATSDR and Mr. Greg McCabe, RPM, EPA Region VII, March 12, 1990). However, a radiological survey is warranted to rule out an unexpected exposure to possible radioactive contaminants that may exist at the designated training areas. We have discussed our concerns with Dr. Paul Charp, Health Physicist, ATSDR who agrees that a walkover survey is necessary, before troops are allowed access to the site.
The draft Remedial Investigation (ref. 3) mentioned that Building G-24 may contain asbestos. This building is located within the designated training area and currently is not occupied. This building is restricted until sampling reveals the absence of asbestos.
Troops training on-site may be exposed through direct contact, ingestion, and inhalation of contaminants. However, it does not seem likely that such exposure would be significant to warrant concern. The scenarios described (ref. 3) overestimate the opportunity for contact with, inhalation of, and ingestion of contaminated soil from the site; The general population will not have access to the site.
CONCLUSION
Based on the information reviewed, lead and TNT and related compounds from the designated training areas on-site pose minimal health risks to U.S. Army Reservists. Exposure to contaminated soils through direct contact, inhalation, and ingestion is possible but not probable under conditions described.
There is a possibility of radioactive contaminants existing on the designated training areas because of past disposal activities within the nearby vicinity. Moreover, the possible presence of asbestos in Building G-24 may pose a health risk to soldiers or other on-site personnel. Exposure to contaminated soils through direct contact, inhalation, and ingestion is possible but not probable under the conditions described.
The conclusion reached for the exposure scenarios evaluated in the Addendum are reasonable risk estimates. However, the assumptions used probably do not represent actual conditions of risk and may or may not overestimate the risk of chronic exposure to the troops training on-site.
RECOMMENDATIONS
PREPARER OF REPORT
| Environmental and Health Effects Assessor: | John E. Abraham, Ph.D, M.P.H. Environmental Health Scientist Emergency Response and Consultation Branch |
| Regional Representative: | David A. Parker
Public Health Advisor Regional Services Region VII |
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Toxicologist Emergency Response Branch, Office of Health Assessment, ATSDR
April 24, 1989, Health Consultation: Fish Data, Chemical Plant Site St. Charles County, Missouri.
Mr. David Parker
Public Health Advisor
EPA Region VII Kansas City, Missouri
Through: Chief, Emergency Response Branch, OHA, ATSDR
BACROUND
The United States Department of Energy (DOE) has completed a fish survey of lakes and ponds at the Weldon Spring Site (WSS) in St. Charles County, Missouri. The WSS is a DOE surplus facility which was previously operated as an ordnance facility by the Department of the Army and as a uranium processing facility by the Atomic Energy Commission. Several ponds are suspected of having elevated heavy metal contamination resulting from surface water run-off from previous site activity. The Environmental Protection Agency (EPA) has requested the Agency for Toxic Substances and Disease Registry (ATSDR) to evaluate the fish data for human health concerns.
DOCUMENTS REVIEWED
Radiological and Chemical Uptake by Selected Biota at the Weldon Spring Site, Draft, November 1988, Department of Energy, DOE/OR/21548-044,
DISCUSSION
The Food and Drug Administration has estimated the average consumption rate of commercial fish for the typical American is around 19 grams per day. The consumption rate for the upper 95th percentile is estimated to be 27 grams of fish per day. While the typical American will consume commercial fish from a variety of sources, sports fishermen and subsistence fishermen are more likely to consume greater quantities of fish than the average American and to consume fish from a restricted geographic area. Therefore, these two subpopulations may be at increased risk when consuming contaminated fish from a particular area. Studies on sports fishermen in the Great Lakes area have shown that, on average, 32 pounds. of sport caught fish are consumed each year with certain individuals consuming as much as 3 to 5 times this average amount. This average fish consumption rate is equivalent to 1 fish meal per week which approximates 280 grams of fish per week or 39.8 grams per day.
Proportionate, composite, fillet samples of sunfish, bass, and crappie were collected from WSS lakes. Catfish were not included in composite samples. Using 39.8 grams fish per day to approximate the fish intake for sport fishermen, one can calculate daily and weekly intake for mercury (Table 1), lead (Table 2) and arsenic (Table 3).
Sport and subsistence fishermen may have a favorite lake or fishing spot from which they obtain the majority of their fish; therefore, the most conservative approach in this case is to assume that the fish consumed are from the lakes with detectable levels of the metal of concern. A great deal of variation can exist in calculated intakes levels. Because these are average values from composite samples, levels are higher in half the fish sampled. Also, variation in heavy metal content in fish fillets certainly exists both within species (depending upon age) and between species (depending upon feeding habits and pharmacokinetics). The manner in which the fillet is prepared for analysis also affects the quantitative results. Therefore, it would be prudent not to rely strictly upon the quantitative results.
The FDA has calculated the dietary intake of mercury in the typical American diet to be 3.2 ug/day. For the adult who consumes one contaminated fish meal per week, the weekly intake for mercury from lakes 34, 35, 36, and 37 would range from 44 - 75 ug/week or 6 - 11 ug/day (see Table 1). This intake is greater than the acceptable intake from water based upon EPA's Maximum Contaminant Level (MCL) of 2 ug/l and is similar to EPA's Rfd for mercury of 0.158 ug/kg/day which is equivalent to an intake of 11 ug/day for a 70 kg adult male. The World Health Organization has established a maximum tolerable intake of 0.3 ug organic mercury/kg/day for adults. This corresponds to 15 to 21 ug of organic mercury per day for adult females and males. The WHO maximum tolerable level was based upon the observation that the long-term daily ingestion of approximately 250 ug per day of mercury as methyl mercury has been observed to cause the onset of neurological impairment. For individuals consuming 1 fish meal per week from fish caught at the WSS, intake levels appear to be below levels that may cause adverse health effects. This conclusion may not be valid for individuals who are consuming fish from WSS on a more frequent basis.
Table 1. Daily and weekly intake values for mercury are depicted for fish consumption where 39.8 g/day of contaminated fish are consumed. This intake level approximates 1 fish meal per week for sport and subsistence fishermen.
| lake | composite concentration (ug/g) | daily intake (ug/day) | weekly intake (ug/week) |
| 34 | 0.27 | 10.7 | 75.2 |
| 35 | 0.24 | 9.5 | 66.9 |
| 36 | 0.16 | 6.4 | 44.6 |
| 37 | 0.23 | 9.2 | 64.1 |
The FDA has estimated an intake of 57 ug/day of lead for the typical American diet. From lead in fish from lakes 34 and 36, the estimated intake from 1 contaminated fish meal per week is approximately 1100 ug/week or 160 ug/day. This intake exceeds the intake of 100 ug/day using EPA's MCL for lead of 50 ug/l and assuming a 2 l/day water consumption rate for the average adult. Populations at increased risk to lead exposure include children and pregnant women, since lead is capable of crossing the placental barrier. For each 100 ug per liter of oral lead intake, an increase of 4-5 ug of lead per 100 ml of blood is expected. WHO has estimated that this intake level may cause a significant number of children to exceed the recommended blood lead level of 25 ug per 100 ml blood. Lead from fish taken from lakes 34 and 36 has the potential for increasing lead exposure to children and pregnant women who consume the contaminated fish.
Table 2. Daily and weekly intake values for lead are depicted for fish consumption where 39.8 g/day of contaminated fish are consumed. This intake level approximates 1 fish meal per week for sport and subsistence fishermen.
| lake | composite concentration (ug/g) | daily intake (ug/day) | weekly intake (ug/week) |
| 34 | 4.0 | 159 | 1,114 |
| 36 | 4.2 | 167 | 1,170 |
The FDA has calculated that the average American dietary intake for arsenic (As) is 46 ug/day. The predominant food source is seafood which ranges from 2 to 10 ug As/g. It is very unusual for freshwater fish to have higher levels than those found in seafood.
For the adult who consumes 1 contaminated fish meal per week from fish taken from lakes 35 and 37, the weekly intake of arsenic is about 3,800 ug/week or 550 ug/day. This intake is much greater than the intake established by EPA's drinking water MCL of 50 ug/l, which is equivalent to 100 ug/day based upon a 2 l/day water consumption rate. An intake of 550 ug/day would be quite unacceptable were the exposure occurring through drinking water. For subsistence fishermen and sport fishermen who have more than 1 fish meal per week from fish taken from lakes 35 and 37, the intake of arsenic obviously would be greater.
Table 3. Daily and weekly intake values for arsenic are depicted for fish consumption where 39.8 g/day of contaminated fish are consumed. This intake level approximates 1 fish meal per week for sport and subsistence fishermen.
| lake | composite concentration (ug/g) | daily intake (ug/day) | weekly intake (ug/week) |
| 35 | 13.9 | 553 | 3,872 |
| 37 | 13.6 | 541 | 3,788 |
Daily intake from contaminated fish at the WSS site has been calculated from the mean fish consumption rate for sport fishermen. Some sport fishermen will have higher intake than those used in these calculations. Also, it is very likely that subsistence fishermen in the area will consume more locally caught fish when compared to sport fishermen. Therefore, their intake of these metals will be increased thus increasing their risk to adverse health outcome.
A problem does exist in the manner in which the fish were collected. The logic was used that fish are eaten according their proportional population within each lake. This logic does not seem reasonable to me for estimating fish consumption patterns since some residents may have a preference for certain species in their diet. In addition, catfish were not sampled in the survey for heavy metal content. It is very likely that catfish comprise a major portion of fish in the diet of subsistence fishermen. Catfish are also likely to have increased levels of heavy metal because of their close association with sediment feeding, which is the sink for heavy metals in ponds and lakes.
CONCLUSION
All individuals receive some quantity of mercury, arsenic, and lead from both dietary and environmental exposure routes. Quantitation of the environmental exposure route (i.e., air and soil ingestion) is not precise and depends largely upon local conditions.
Quantitation of dietary intake has been made by FDA from food baskets surveys. The intake of heavy metals found in fish at the WSS is in addition to this background exposure.
The occurrence of heavy metals in composite fish samples from the WSS does not present a public health threat to area residents who have occasional fish meals from locally caught fish. However, sport fishermen and subsistence fishermen may be at increased risk to adverse health effects if a major portion of the fish in their diet comes from the lakes with heavy metal contaminated fish. A great deal of variation exists in the fishing and eating habits of these two populations; therefore, it is difficult to quantitate their metal intake with certainty. By using the average consumption rate for sport fishermen from the Great Lakes area, one can obtain some quantitative idea of the potential intake levels. However, because of uncertainty in estimating dietary fish intake, one should not rely strictly upon the quantitative results which tends to indicate a potential problem. The major concern involves those individuals and their families who rely heavily on fish from the WSS. This population has the potential for exceeding the safety factor used in establishing acceptable heavy metal intakes.
RECOMMENDATIONS
1. Collect composite samples of species specific fish from lakes in the WSS. Include catfish as a separate species to be evaluated.
2. Identify subpopulations, like sport fishermen and subsistence fishermen who might use the lakes at the WSS and educate them to the potential hazard.
3. Fish from the WSS should not be consumed more than once per month.
David N. Mellard, Ph.D.
February 10, 1993, Health Consultation
UID #:s j h 0 Date:02/10/93 Time:10:00 am X pm
Site Name: Weldon Spring City:Weldn Sprng Cnty:St Charles State:MO CERCLIS #: Cost Recovery #: 703S Region:07
Site Status (1) X NPL Non-NPL RCRA Non-Site specific Federal
(2) Emergency Response Remedial X Other
Activities
Incoming Call Public Meeting X Health Consult Site Visit
X Outgoing Call Other Meeting Health Referral Info Provided
Conference Call Data Review Written Response Training
X Incoming Mail Other
Requestor and Affiliation:(1 ) Cecilia Tapia EPA Region VII
Phone: (913) 551-7733 Address:
City: Kansas City State: KA Zip Code: 66101
Contacts and Affiliation
(31) Dave Parker ( ) ( ) ( )
| 1-EPA | 2-USCG | 3-OTHER FED | 4-STATE ENV | 5-STATE HLT |
| 6-COUNTY HLTH | 7-CITY HLTH | 8-HOSPITAL | 9-LAW ENFORCE | 10-FIRE DEPT |
| 11-POISON CTR | 12-PRIV CITZ | 13-OTHER | 14-UNKNOWN | 15-DOD |
| 16-DOE | 17-NOAA | 18-OTHR STATE | 19-OTHR COUNTY | 20-OTHR CITY |
| 21-INTL | 22-CITZ GROUP | 23-ELECT. OFF | 24-PRIV. CO | 25-NEWS MEDIA |
| 26-ARMY | 27-NAVY | 28-AIR FORCE | 29-DEF LOG AGCY | 30-NRC |
| 31-ATSDR |
Program Areas
Health Assessment Health Studies Tox Info-profile Worker Hlth
Petition Assessment Health Survellnc Tox Info-Nonprofil Admin
Emergency Response Disease Regstry Subst-Spec Resch Other
X Health Consultation Exposr Regstry Health Education
Narrative Summary: EPA requested that ATSDR comment on the health implications of lead, arsenic, and mercury in fish caught at the Weldon Spring site. Whole fish and fish fillets (edible portion) were analyzed for the three metals using a detection limit of 0.10 mg/kg.
Lead was found in two whole fish samples above the detection limit at a maximum concentration of 0.176 mg/kg. Mercury was found in a fish fillet at a maximum concentration of 0.212 mg/kg. Arsenic was not found in any whole fish or fish fillet samples above the detection limit.
Action Required/Recommendations/Info Provided: I advised EPA that the lead, arsenic, and mercury did not represent a health threat to persons eating the fish. I also advised EPA that, at the reported concentrations, harmful effects from subsistence consumption of fish would not be expected.
cc: Ed Skowronski
RIMB
Dave Parker
1993 Letter on Proposed Cleanup Levels
Mr. Stephen H. McCracken
U.S. Department of Energy
Weldon Spring Site
Remedial Action Project Office
7295 Highway 94 South
St. Charles, Missouri 63304
Dear Mr. McCracken:
The Agency for Toxic Substances and Disease Registry has been asked to provide written comments to you concerning the public health aspects of the "Proposed Plan for Remedial Action at the Chemical Plant Area of the Weldon Spring Site". This document proposes remedial actions for contaminated materials, soil cleanup standards, and identifies a disposal decision for wastes generated during remediation. This letter will address the adequacy of the proposed soil cleanup standards and the potential for human exposures to those waste materials.
The public health concerns of the proposed remedial actions are specifically addressed in an ATSDR Health Consultation, which is currently in internal review. This letter is to insure that ATSDR comments are received during the public comment period for the proposed plan. The Health Consultation will also be forwarded to you as soon as possible.
ATSDR has two primary concerns with the proposed plan. First, the off-site (or vicinity) properties which have been determined to have radiological contamination have not been evaluated for non-radiological contaminants. Although cleanup of radiological contaminants at these sites may remove/remediate non-radiological contamination, these are the sites for which there is current exposure potential and DOE will not retain access restrictions. Additionally, several of the off-site areas may have been subject to prior contamination by Ordnance Works operations, which presents the potential for significant remedial worker exposure and safety hazards. ATSDR recommends, that in the off-site areas, non-radiologic soil contaminant screening be conducted and that site remediation be coordinated with ongoing Ordnance Works site characterization.
The second concern is the proposed cleanup standards (ALARA Goals). The ALARA Goals for arsenic, chromium VI, dinitrobenzene, nitrobenzene, trinitrobenzene, and trinitrotoluene exceed health-based comparison values for ingestion exposures for pica children (assumed soil ingestion rate of 5,000 mg/day). The ALARA Goals for dinitrobenzene, nitrobenzene, and trinitrobenzene are also greater than comparison values for non-pica children (assumed soil ingestion of 200 mg/day). Arsenic, PAHs [benzol(a)pyrene], and PCBs (Aroclor 1248, 1254, and 1260) are known or suspected carcinogens and the proposed ALARA Goals are greater than appropriate comparison values.
Calculation of the comparison values assumes chronic exposure to the contaminated soil. Currently, there are no chronic exposures to Chemical Plant Site soils for the public because site access is restricted. However, the cleanup goals were derived assuming unlimited public access. Under the scenario of residential occupation of the contaminated area, the proposed cleanup goals would not be protective of human health. Thirdly, the proposed plan has not demonstrated that future potential doses due to radioactive materials at the site will be within the recommendations of the International Commission on Radiation Protection (ICRP Publication 60). Calculation of radiation dose includes the accumulation of radioactive materials within the body throughout one's expected life (i.e. 70 years). The proposed plan does not detail how or if that was completed.
Using the Baseline Assessment for the Chemical Plant Area of the Weldon Spring Site (BHA) as an indicator, the BHA included calculations for doses over an individuals working-life-span of 50 years for either 10 year or 30 year exposure scenarios. Those scenarios do not include dose estimates for the pca-child nor are they representative of the public's expected life-span. To determine whether the ALARA Goals for the radioactive soil are protective of public health, exposure scenarios should account for pica-child, child, and adult activities. The doses from those scenarios should be evaluated for the expected life-span of an individual, 70 years, as specified by the ICRP.
Accidental or intermittent exposure to soils remediated to ALARA Goals should not be of public health concern if safety procedures and site access restrictions, as outlined in the "Feasibility Study for Remedial Action at the Chemical Plant Area of the Weldon Spring Site", are maintained.
Respectfully yours,
Sally L. Shaver
Chief
Federal Programs Branch
Division of Health Assessment
and Consultation
January 20, 1994, Health Consultation
Record of Decision for Quarry Bulk Wastes, Weldon Spring Remedial Action Project, (703S)
Federal Programs Branch
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
January 20, 1994
BACKGROUND AND STATEMENT OF ISSUES
The Agency for Toxic Substances and Disease Registry (ATSDR) was requested by the United States Department of Energy (DOE) to evaluate the human health hazards posed by its Interim Remedial Action Plan for removing bulk wastes from the Weldon Spring quarry. As described in the Record of Decision [ROD; 1], the plan calls for bulk wastes to be removed from the quarry, using standard equipment and procedures, and transported to a temporary storage area at the Chemical Plant site using a private road. This ROD does not include information or remedial alternatives for the following: 1) permanent disposal of the bulk wastes, 2) the quarry proper, 3) surface water, or 4) groundwater.
A. Background
The Weldon Spring quarry is a 15-acre area of the Weldon Spring Quarry/Plant/Pits site (220 total acres) that was listed on the EPA National Priorities List (NPL) in July 1987. In March 1989, this listing was expanded to include the chemical plant and raffinate pits. The quarry is about 4 miles south-southwest of the chemical plant area, 5 miles southwest of the city of Weldon Spring, 1 mile west of the Missouri River, and about ½ mile northwest of the St. Charles County wellfield. The quarry is on Missouri Route 94, but public access is restricted by a fence and 24-hour security guard. The quarry is about 1,000 ft. long, 450 ft. wide, covers an area of two acres, and the depth varies from about 30 to more than 100 ft. [2].
Before 1942, the quarry was used as a source of construction limestone. From 1942 to 1957, the Army (or its contractors) used the quarry to dispose of off-specification explosives and explosive-contaminated materials. From 1957 to 1969, the quarry was used to dispose of building rubble, soil, and sludges contaminated with radioactive materials. The Remedial Investigation for Quarry Bulk Wastes [3] summarizes contaminant concentrations and distributions and estimates the total volume of waste within the quarry is 95,000 cubic yards. The Baseline Risk Evaluation [2] identifies specific contaminants of concern, average concentrations, ranges, and estimated waste volumes.
B. Statement of Issues
Several studies, as summarized in the Remedial Investigation [3] and the Baseline Risk Assessment [2], have identified the bulk wastes in the Weldon Spring quarry as hazardous because of radiological and chemical contamination. ATSDR previously identified the quarry as a public health concern because of the potential for on-site radiation exposure, bioaccumulation of contaminants in food chain, and migration of contaminants to the St. Charles County wellfield [4]. Excavating the waste material and transporting it to temporary storage at the chemical plant site is the alternative specified in the ROD [1]. The basic issue addressed in this consultation is whether the proposed activity is protective of public health.
DISCUSSION
Remedial workers may be exposed to quarry bulk wastes during the excavation, transport, and storage processes. The use of dust suppression techniques, site and waste monitoring, worker training, and other standard procedures for minimizing worker exposures as indicated in the Feasibility Study [5] should eliminate the potential for adverse health effects. Mitigative measures to be used for worker protection include: 1) developing an activity-specific environmental, safety, and health plan; 2) monitoring worker health/exposure; 3) monitoring the workplace environment; and 4) making available and using protective equipment, such as respirators, protective clothing, and showers (if necessary). Public and worker exposures during quarry excavation will be mitigated by keeping inactive excavation areas covered, wetting the active excavation area and materials, and covering surfaces and materials.
The waste materials will be transported in closed containers on a private haul road so that public exposures do not occur during transport. Public exposure during excavation is unlikely because there are no residents or businesses adjacent to the quarry. Worker exposure is possible as a result of radon inhalation and transportation accidents; however, mitigative measures to prevent such accidents will include: 1) transport in closed, leakproof trucks (DOT approved for transport of low-specific activity materials), 2) vehicle decontamination before quarry departure, 3) a 20 mph speed limit, 4) personal protective equipment, and 5) pressurized truck cabs.
Public exposure to bulk wastes during temporary storage at the chemical plant is not likely because of access restrictions, site monitoring, and the design characteristics of the storage area [5]. The temporary storage area (TSA) at the chemical plant site is within a patrolled, chain-link/barbed wire fence enclosure. Sludge retention areas within the TSA will be double-lined with stormwater runoff and leachate diverted to lined collection ponds and the water-treatment plant. Areas of the TSA susceptible to wind-erosion will be covered and dust-suppression techniques will be used for the entire area [5]. The TSA contains site monitors for air particulates, radon, and radon-decay products, and groundwater monitoring of chemical and radioactive contaminants.
CONCLUSIONS
The quarry is a public health concern and overall remediation of the site requires excavating and removing bulk wastes. Based on available data, the excavation, transport, and temporary storage of the quarry bulk wastes will not present a potential for public exposures to hazardous wastes. There is a potential, however, for worker exposure, but that can be minimized if existing standard procedures for dust suppression, site monitoring, worker training, and safety procedures are followed. These conclusions are specific to the quarry bulk wastes and should not be considered applicable to quarry surface water, groundwater, or residual contamination after removal of bulk wastes.
RECOMMENDATIONS
ATSDR recommends that the following steps be taken to protect public health:
PREPARER OF REPORT:
August 30, 1994, Health Consultation
Evaluation of Potential Radiation Exposures at the Francis Howell High School from the
Weldon Spring Site, Federal Facilities Assessment Branch
August 30, 1994
BACKGROUND AND STATEMENT OF ISSUES
The St. Charles Countians Against Hazardous Waste have requested the Agency for Toxic
Substances and Disease Registry (ATSDR) to evaluate potential exposure of the Francis Howell
High School students and staff to radioactive materials from the Weldon Spring Site (WSS). The
high school has approximately 2,300 students and staff members and is located approximately
one-half mile east of the WSS [1]. Demolition of buildings contaminated with uranium (U),
thorium (Th), or radium (Ra) is underway and may be a source of airborne particulates.
The WSS is an inactive uranium processing facility that is currently managed by the Department
of Energy (DOE) as a U.S. Environmental Protection Agency (EPA) Superfund site. The site
includes four processing waste lagoons (raffinate pits), the Chemical Plant buildings and
grounds, a nearby quarry used for mixed waste disposal, and other off-site areas containing
radioactively contaminated soils [1]. The WSS was built on part of a 17,000 acre WWII era
ordnance plant (Weldon Spring Former Ordnance Works; WSFOW) that manufactured TNT and
DNT munitions and resulted in widespread chemical contamination [2]. The former ordnance
works is also an EPA Superfund site that is being cleaned up by the U.S. Army.
The WSS is in St. Charles County, Missouri, 30 miles west of St. Louis and about 2 miles west
of the Weldon Spring and Weldon Spring Heights communities [1]. The WSS is bordered by
state-owned wildlife management areas to the north, south and east, and by the Weldon Spring
Training Area (WSTA) to the west. The former ordnance works included all of the wildlife
management areas, the WSS and the WSTA. The WSTA is controlled by the Army and used for
troop training activities. People hunt, fish, and hike in the wildlife management areas, which
include some areas of radioactive and chemical contamination [3]. A state-owned highway
maintenance facility is adjacent to the WSS along the east boundary.
Radioactive and chemical contamination of both on- and off-site soil, sediment, surface water,
and groundwater at the WSS have resulted from past operations of the uranium refining facility
and the ordinance manufacturing facility [2]. However, both surface waters and groundwater
from the site flow north or south and away from the high school, and the resulting contaminated
lake and stream sediments follow the same drainage pattern to the north and south [1].
ATSDR reviewed a 1986 survey of radioactive contamination which indicated that the only
significant sources for airborne releases at WSS and nearby areas lie within the boundaries of the
WSS [4]. The study did not report any data for the high school property; however, Highway 94,
which leads to the high school, was monitored and no elevated gamma readings were found on
Highway 94 near the high school.
DOE has collected the following environmental data which ATSDR reviewed for this
consultation. ATSDR reviewed the annual alpha air monitoring data which are used to monitor
migration of radionuclides which decay through alpha emission (i.e., uranium, thorium, and their
decay products). In 1989 and 1990, WSS reported gross airborne alpha concentrations in a
manner consistent with DOE guidelines at the time: if the measured alpha radioactivity was
below the "lower level of detection" (LLD) of the analyzing instrument, the LLD was reported
instead of the measured activity. These data are preceded by the less than symbol (<) [5,6]. In
1991, WSS, consistent with changing DOE guidelines, stopped the use of LLD values when
reporting gross alpha concentrations [7]. ATSDR reviewed ambient radon concentrations near
the Francis Howell High School and background locations reported by WSS for the years 1989 -
1991. ATSDR also reviewed particulate radionuclide concentrations in air [4]. Isotopic analysis
of air samples collected from the Francis Howell High School and background locations were
performed by WSS from 1990 to 1993. The radionuclides measured by WSS include U-238, U-235, U-234, Th-230, Ra-226, Th-232, Ra-228, and Th-228.
DISCUSSION
ATSDR compared gross3 alpha air concentrations at different locations to determine if alpha-emitting radionuclides are migrating from their source locations. If the measured gross alpha air
concentrations are greater than that of background, then migration of alpha emitting
radionuclides may be occurring from source areas. (Gross alpha data alone are not sufficient for
calculating radionuclide concentrations in air.)
Because WSS reported the gross alpha concentrations with LLDs ("<") prior to 1991, data
reported prior to 1991 can not be compared to data collected subsequently. Therefore, ATSDR
has used 1991, 1992, and 1993 gross alpha data; and their averages are tabulated below in Table
1.
TABLE 1. AVERAGE ANNUAL GROSS CONCENTRATIONS IN AIR (10-15Ci/ml).
µCi/ml - microcurie per milliliter The 1991, 1992, and 1993 average gross alpha concentrations at the perimeter of contaminated
areas are essentially the same as levels at the high school and background locations. This
indicates that no migration above background of alpha-emitting radionuclides in air occurred
from the chemical plant, the raffinate pits, or the quarry towards the high school between 1991
and 1993 [this includes the recent period of building demolition at the site].
ATSDR also compared the range of radon concentrations (alpha track results reported 1989 -
1991) in background areas to the range at the high school. The range of radon concentrations in
background areas is 0.04 - 1.3 picocurie per liter (pCi/L) of air, and the range at the high school
is 0.1 - 0.8 pCi/L. The range of radon concentrations at the high school is within that of
background areas; therefore, radon emissions from the WSS do not appear to impact persons at
the high school. Furthermore, radon levels at both the high school and WSS do not represent a
public health concern.
In 1990, WSS began performing isotopic analyses of particulate air samples [6]. The results of
isotopic analyses are at or near the analytical detection limits, and the uncertainty associated with
the results are large [10]. Therefore, ATSDR did not use these data.
CONCLUSIONS
1) ATSDR concludes that contamination from WSS and building demolition does not pose a
public health concern for persons at the Francis Howell High School. This conclusion is based
on the following information: the characterization study, which indicates that property at the high
school is not contaminated; gross alpha measurements, which show that no airborne migration of
alpha-emitting radionuclides is occurring from the site to the high school; and radon data, which
indicate that radon emissions from WSS do not contribute to radon exposures at the high school.
RECOMMENDATIONS
1) Continue monitoring airborne radionuclides at appropriate locations in order to ensure public
confidence in the waste management processes at the WSS.
Consultation Prepared By:
Mark W. Evans, Ph.D.
William Taylor, Ph.D.
Jack Hanley REFERENCES
APPENDIX F: RESPONSE TO PUBLIC COMMENT
ATSDR released the Public Comment draft of the Public Health Assessment of the Weldon
Spring Quarry/Plant/Pits (USDOE) on September 30, 1996. The comment period ended
November 29, 1996. During that period, we received one comment from the public. A summary
of that comment and our response is provided below.
1. From the National Council on Radiation Protection and Measurements, Report No. 103, p. 5.
1. The annual limit on intake (ALI) of the public is used as the annual amount of a radionuclide a member of the public can inhale or ingest which delivers the annual public dose limit of 100 mrem per year.
2. ATSDR uses the most current ALIs listed in ICRP 61.
3. Gross alpha concentrations = net concentrations due to source + concentrations due to background
Mark W. Evans, Ph.D
Environmental Geologist
Energy Facilities Assessment Section
Federal Programs Branch
Division of Health Assessment and Consultation
Weldon Spring Remedial Action Project, (703S)
Division of Health Assessment and Consultation
Monitoring Location
1991
1992
1993 Chemical Plant & Raffinate
Pits
1.40
1.18
1.14 Quarry
1.52
1.10
1.11 High School
1.36
1.06
1.04 Background
1.37
1.23
1.02 Michael Grayson
Comment: "...There is one area which I believe has been omitted in trying to identify a reason
for the excessive leukemia rate in St. Charles County. As shown in some of the County's wells,
radioactive contamination is a factor due to underlying bedrock in St. Charles County.
Apparently there lies a bed of radioactive rock some 300 feet below the surface, which has
contaminated some wells in the county. Could someone look into the possibility of radon arising
from this deeply buried layer of radioactive materials? At this point, some further studies could
be done by placing radon monitors in many basements and homes in the County where actual
cases of leukemia have occurred. If this proves to identify no radon, then one more cause can be
ruled out...."
Response: Generally, an excessive leukemia rate would not be attributed to radon emanating
from a bedrock 300 feet below the surface for two reasons, (1) radon sources located more than a
few meters (6.5 - 10 feet) below ground are unlikely to increase radon concentrations at the
surface1, and (2) although leukemia has been linked to radiation exposure, specifically elevated
gamma and x-ray exposure, it has not been causally linked to radon exposure.
Agency for Toxic Substances and Disease Registry, 1825 Century Blvd, Atlanta, GA 30345
Contact CDC: 800-232-4636 / TTY: 888-232-6348
