PETITIONED PUBLIC HEALTH ASSESSMENT
HANSEN CONTAINERS
GRAND JUNCTION, MESA COUNTY, COLORADO
The Hansen Container Company Site (also known as the Layton Brothers Drum Company and the Rock Mountain Drum Company) was an 11-acre drum recycling facility located on the southern edge of the Grand Junction city limits, Mesa County, Colorado. The facility reconditioned structurally sound drums used to transport chemicals and other materials from the mid-1950's until January 1991 (ATSDR, 1991a). In March 1991, two Grand Junction residents petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) to conduct a Petitioned Public Health Assessment of the Riverside Community (CCRA,1991).
ATSDR prepared this Petitioned Public Health Assessment and classified the Hansen Container Company site (Hansen Containers) as a past public health hazard. This classification was based on the fact that: in the past, children had unrestricted access to the lead contaminated soil on the Hansen site. Currently, Hansen Containers is classified as a no public health hazard because: 1) operations at the facility ceased in 1991; 2) site access was restricted; and, 3) remedial activities were completed at the site in 1996. The site was remediated under a joint effort by the Environmental Protection Agency (EPA) and the Department of Energy (DOE). The EPA removed drums and debris that remained on the site after site closure and stabilized and immobilized the contaminated on-site soil. DOE removed the stabilized soil and buildings from the site with a program they manage called the Uranium Mill Tailing Remedial Action (UMTRA) program. These actions eliminated the contaminants at the site. Therefore, exposures to contaminants at the site were eliminated.
After ATSDR's initial site scoping in 1991, a Public Health Advisory was issued to inform the community and local and federal agencies about conditions that indicated that the facility may pose an urgent health hazard. The health advisory documented that the site was unrestricted and ATSDR had concerns about potential health effects associated with exposures to lead. As a result of the issuance of the Health Advisory, the Colorado Department of Public Health and Environment (CDPHE), in cooperation with ATSDR and other federal and local agencies conducted blood lead screening for children and adults in the area. The information was needed to better characterize potential health effects from lead exposures. The screening identified six children under 6 years old with slightly elevated blood lead levels. CDPHE interviewed the families of the six children and identified several factors that could have resulted in exposures: peeling paint in the home, remodeling in the home, pica behavior, possible occupational exposures of a parent, and recent residence in Mexico. Each family received a written report of their test results and health and prevention information in spanish and english. CDPHE also contacted the physicians of the children with elevated blood lead levels and provided them with educational materials regarding was to reduce exposures. Two of the children with elevated blood lead levels were re-tested 11 and 14 months after the initial blood testing and had no elevated blood lead levels. Since October 1993, CDPHE has had a full-time childhood blood lead surveillance coordinator in the Disease Control and Environmental Epidemiology Division; this has allowed the agency to actively pursue test results and to collect data. In September 1994, CDPHE conducted additional follow-up on the six children and did not identify elevated blood lead levels.
Contaminants of concern identified at the site included: lead, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PHAs), pesticides, radionuclides, and various volatile and semi-volatile organic compounds. Lead was considered the primary contaminant of concern to the community. Direct contact with lead contaminated soil or dust (through incidental ingestion and/or inhalation) were the most likely routes of exposure. Ingestion of lead contaminated soil at the levels detected in the past could result in reduced kidney function, gastrointestinal problems, neurological, reproductive, and hematological effects.
ATSDR identified a past completed exposure pathway for the site while it was operable and unrestricted. Children and adults who accessed the site for recreational purposes and/or site workers may have been exposed to soil and airborne contaminants through inhalation and incidental ingestion of the contaminated media. Potential exposure pathways include: 1) secondary exposure through inhalation to lead and other contaminants that the site workers may have transported on their clothes to their homes; 2) the potential for children and adults to be exposed to radioactive material found at the site prior to the site remedial activities; and, 3) exposures through inhalation of soil gas contaminants that migrated from the site to the Riverside neighborhood.
The community expressed concerns about health effects associated with exposures to sire-related contaminants. Specifically, they were concerned about: 1) the health effects associated with exposures through incidental ingestion, inhalation, or dermal contact with on-site and off-site contaminants; 2) lead exposures to site workers during working hours and the potential for exposures to family members due to lead transport on the worker's clothes; 3) transport of contaminants from the facility to neighboring houses through runoff from the site resulting in dermal or inhalation exposures to the dusts carried off-site; 4) inhalation of particulates and gases from the incinerator and from smoldering drums leaving the incinerator; 5) dermal exposure to particulates and polymers; 6) exposure to dusts generated during the process of emptying the drums; and, 7) exposure to contaminants through ingestion of contaminated garden produce. One resident also expressed concern about the incidence of cancer.
While preparing this Petitioned Public Health Assessment (PPHA), ATSDR made the following recommendations: 1) locate former site workers who were exposed to lead for follow-up health activities; 2) evaluate the potential migration of soil-gas from the site; 3) educate the community and health professionals about the contaminants of concern identified at the site and potential health effects associated with exposures through inhalation, dermal contact, and ingestion of the contaminated media; and, 4) ensure the protection of people on and off the site during the remediation process.
Since the remediation process was completed in the spring of 1996, ATSDR requested the data from the remedial actions. We will evaluate the data to ensure that the removal is complete and no contaminants remain on the site and provide appropriate recommendations.
ATSDR evaluated the contaminants in the subsequent sections of this document and determined whether exposures had public health significance. ATSDR selected and discussed the contaminants based on the following factors:
The presentation of a contaminant in the data tables in Appendix D indicates which contaminants were evaluated further in this document, not that they resulted in adverse health effects from exposures at the levels detected. These data are representative of the samples collected in the different media prior to the completion of the removal actions at the site.
Comparison values for ATSDR public health assessments are contaminant concentrations in specific media that are used to select contaminants for further evaluation. ATSDR and other agencies develop the values to provide guidelines for estimating the media concentrations of a contaminant that are unlikely to cause adverse health effects, given a standard daily ingestion rate and standard body weight (see Appendix D for a description of the comparison values used in this public health assessment).
After the completion of the removal actions at the site, ATSDR evaluated the data collected from the different media. The removal activities were completed in 1996 and these actions eliminated the exposures to contaminants previously detected at the site. Currently, there are no known routes of human exposures and future exposures to contaminated media were eliminated during the removal activities at the site. Therefore, no public health actions are recommended because no human exposures are occurring or are likely to occur in the future. In the following subsections, ATSDR presents data analysis conducted prior to the site removal activities.
A. On-site Contamination
On-site Surface Soil
On August 31, 1989, CDPHE/Hazardous Material Waste Management Division (HMWMD) collected four on-site grab soil samples from an unspecified depth. These samples were sent to CDPHE/Organic Chemistry Laboratory on September 5, 1989 and analyzed for pesticides and volatile organic compounds (CDPHE, 1989). On February 8, 1990, CDPHE/Inorganic Chemistry Laboratory analyzed the samples for their metal content (CDPHE, 1990b). A blank sample was submitted with the soil samples. Pesticide and total arochlor(1) levels were all below detection levels in the blank sample; pesticides below detection limits were not reported.
On-site soil samples were also collected from May 24 to July 9, 1989 (Figure 6). Sampling depths ranged from 0-36 inches and 0-42 inches (UNC Geotech, 1990b). The results of all the analyses described above are summarized in the Tables 1, 2, and 3 in Appendix C.
On May 2, 1990, three soil grab samples were collected from unidentified depths. The samples were analyzed for total metals and volatile organic compounds (VOCs). In addition to these analyses, one of the samples was examined for pesticides and was found to be below the laboratory's analytical detection limit. On June 5, 1990, EPA's Special Environmental Analysis Section analyzed the samples for VOCs and pesticides (EPA, 1990). On August 20, 1990, CDPHE/Inorganic Chemistry Laboratory analyzed the samples for metals (CDPHE, 1990a).
From July 16 - 18, 1991, additional on-site soil samples were collected (Ecology and Environment, 1991c). During these sampling rounds, a portable detector was used to screen for lead contamination in surface soil. Lead was detected at concentrations ranging from 0 to 10,000 ppm (Figure 4, Appendix A).
On-site Subsurface Soil
As part of the July 16 - 18, 1991 sampling rounds, the site was "gridded" into 50 by 50 feet sections that were sampled for organic soil gas and surface metal contamination. However, due to the drum stacks, metal debris, and crushed car body parts on the site, it was difficult to grid those areas and impossible to collect samples at those locations (Ecology and Environment, 1991c). Soil cores were collected for confirmation at 10% intervals. At the locations where contamination was detected, a 36 inch soil core was collected with a Shelby tube inserted by a Geoprobe. The bottom of the soil core was taken as a grab sample for VOCs and the rest of the core was composited and analyzed for semi-volatile organic compounds, pesticides, PCBs, and metals (Ecology and Environment, 1991c). The data are summarized in Tables 1, 2, and 3 in Appendix C.
From October 14 - 16, 1991, subsurface soil samples were collected with a backhoe at approximate depths of 7 feet and 15-20 feet (Ecology and Environment, 1991b). After digging the trench, grab samples were taken from the middle of the backhoe bucket. During the sampling efforts 10 trenches were excavated and 20 sample sets were collected. The grab samples were analyzed for volatile and semi-volatile organic compounds, pesticides, PCBs, and metals. As part of this process, workers noted debris present at the excavated depths, possibly indicating previous excavation at the site. Exposure to on-site contaminants at the depths sampled (sampling depths ranged from 3 to 20 feet) is considered improbable.
On-site Soil Gas
From July 16 - 18, 1991 organic soil gas samples were collected from the gridded areas using an organic vapor analyzer (Ecology and Environment, 1991c). A geoprobe was used to install 2-foot deep soil gas screening holes to detect organic gas contamination and collect soil cores for confirmation samples. Confirmation samples were collected at 10% intervals. Confirmation samples consisted of 36 inch soil cores collected with a shelby tube inserted by a geoprobe. The bottom of the soil core was composited and analyzed for semi-volatile organic compounds, pesticides, PCBs, and metals. The sampling identified organic vapor levels ranging from 0 to 100 ppm with an average of 5.5 ppm and a median of 1.8 ppm; however, the organic gas or gases could not be identified (Figure 5, Appendix A).
On-site Waste Material
On May 2, 1990, one grab sample was collected from each of two drums found on-site. CDPHE's Inorganic Chemistry Laboratory analyzed one of the samples for total metals
(CDPHE, 1990a). EPA's Environmental Services Division analyzed the samples for volatile organic compounds (EPA, 1990).
As part of the July 16 - 18, 1991 soil sampling rounds, the EPA's on-scene coordinator (OSC) designated grab samples. The samples included: an ash pile; the entrance to the burner; the burner pit; an ash collection drum; a drain area; and, an oily sump (Ecology and Environment, 1991c). The results are summarized in Tables 4 and 5, Appendix C.
On-site Radioactive Material
Inspectors from CDPHE's HMWMD noted 20 to 30 drums identified as containing yellow-cake (CDPHE, undated). Yellow-cake is a final precipitate formed in the milling of uranium ores. During the August 21, 1987 sampling at the site, radiation levels near the incinerator were 1 millirem per hour (mR/hr) (EPA, 1991a).
Radiation levels ranging from 0.1 to 4.2 mR/hr were detected in a survey of the site performed during June 5-7, 1984. The apparent source of the radiation were 12 drums found on the premises (EPA/NEIC/DENVER, undated). The drums were removed from the site during the site remediation. In addition, thirty drums containing yellow-cake were stored in a semi-trailer located next to an occupied house (ATSDR, 1991a); these drums were also removed as part of the remediation process.
During the collection of an on-site ash sample, the radiation reading at the ash pile was 10 times above background (Ecology and Environment, 1991c); however, EPA's on-site coordinator (EPA/OSC) noted that the instruments were not read correctly and subsequent field radiation readings showed that the initial measurements were inaccurate and were reported as ten times higher than those later measured. Therefore, the readings were actually 1 mR/hr with readings of 10 mR/hr at some hot spots (ATSDR, 1993a). As part of the drum removal actions, sources of low level radiation, primarily in the form of beta and gamma emitters, were detected in various drums containing an ash-like material. Low level radioactive drums were set aside and were disposed of as part of the uranium mill tailings cleanup efforts in Grand Junction (Ecology and Environment, 1993).
On-Site Ambient Air
From September 12 - 15, 1989, airborne contaminant data were collected from the parking lot area and from approximately 100 meters downwind from the incinerator (UNC Geotech, 1990a). The samples were analyzed for volatile organic compounds, semi-volatile organic compounds and endosulfan and endosulfan I. During the September 12 sampling rounds, ethyl benzene and xylene were detected (Table 6, Appendix C).
B. Off-site Contamination
Off-site Surface Soil
From September 24 - 26, 1991, residential surface soil samples were collected from 125 locations throughout the Riverside community; 115 residents agreed to have their soil sampled and composite samples were collected from each home (Figure 7). The samples were analyzed for metals, polyaromatic hydrocarbons (PAHs), chlorinated pesticides and polychlorinated biphenyls (PCBs). Thirty-three of the samples were also analyzed for dioxins and furans and an additional 11 grab samples were collected from areas near the site and analyzed for metals and PAHs (Ecology and Environment, 1992a). Sampling locations were determined on a property-by-property basis, generally in high traffic areas - such as walkways and/or play areas (Ecology and Environment, 1992a). Tables 7, 8, 9, and 10 in Appendix C summarize the results for this sampling program. Off-site lead contamination was further characterized because of concerns about exposures to children in the area (discussion is presented in the subsection below).
Lead in Residential Soils
From September 24 - 26, 1991, soil samples were collected from residential properties and analyzed for metals including lead (Ecology and Environment, 1992a). Off-site lead contamination was further characterized, because of concerns with exposure of area children to lead. The results of the lead analysis are summarized in Table 11 and 12, Appendix C.
Approximately 94% of the residential samples collected showed lead levels equal to or below 300 ppm; of the samples in this range, 85% were below 200 ppm (Table 12, Appendix C). Soil samples were also collected from the Headstart Children's Center. Lead was detected at 21 ppm. In addition, lead was detected at 55.4 ppm in samples collected from the vacant lot on Crawford Avenue.
The mean concentration of lead in the western United States is 17 ppm with an observed range of approximately 10 to 700 ppm (ATSDR, PHAGM, 1992). In the Riverside neighborhood, three values were noted above 700 ppm; with an average concentration of 158 ppm. However, due to the considerably uneven distribution (asymmetry) of the lead levels detected, the median(2) is a better representative of the levels detected. The median of the soil lead values from the Riverside community is 113.0 ppm.
Off-site Radioactive Material
As part of the September 24 - 26, 1991 residential soil sampling rounds, elevated radiation readings were detected at three locations on West Main Street. The highest reading encountered was 0.15 mR/hr above background (Ecology and Environment, 1992a). An association of these readings with potential releases from the Hansen Container facility is considered unlikely due to the distance from the facility; however, the three locations are close to each other and close to one of the main entrances to the Riverside neighborhood.
The Department of Energy (DOE) performed gamma radiation scans in the Riverside neighborhood and completed the remediation process for the properties that were eligible under the Uranium Mill Tailings Remedial Action (UMTRA) program. DOE sent certification letters to the property owners indicating that their properties were remediated under UMTRA in accordance with EPA criteria.
C. Quality Assurance and Quality Control
In preparing this Public Health Assessment, ATSDR relies on the information provided in the referenced documents. The Agency assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this document is determined by the reliability of the referenced information.
As part of the site screening process and the sampling conducted from July 16 - 18, 1991, the environmental sampling group attempted to grid the site into 50' X 50' sections; however, due to the large amount of stacked drums, metal debris, and crushed car bodies on the site, the staff encountered difficulty in gridding and were unable to obtain samples in some locations. They also discovered a subsurface obstruction at location EP-9 during the screening and were unable to collect soil gas or surface soil samples from this location. Additionally, during the collection of the grab samples in the main building the staff noted that the sample from the oily pit was two-phased and the laboratory could not analyze the sample due to the fact that two-phased analyses were not covered under their contract.
On May 2, 1990, three soil grab samples were collected. Analyses of the samples found pesticides at levels below the laboratory's analytical detection limit. However, some of the analytical detection limits are above our comparison values; therefore, this pesticide analysis is not adequate to enable us to evaluate the potential health impact from exposures.
The data collected from May 24 to July 9, 1989 (Tables 1, 2, and 3) represent only an average concentration for the bore samples collected from 0-36 inches in depth; from this data, it is impossible to determine whether the contaminant concentrations identified were found in surface or subsurface soil. If the concentrations were confined to the surface, the reported values would underestimate the concentrations actually found in surface soil. In addition, if the contaminants were confined to subsurface soil, the potential for exposures would be greatly reduced or eliminated (given the history of practices at the facility, this is a likely scenario).
From July 16-18, 1991, organic soil gas samples were collected from the gridded areas of the site. The sampling identified organic vapor levels ranging from 1 - 100 ppm with an average of 5.5 ppm and a median of 1.8 ppm; however, the organic gas or gases could not be identified.
To determine whether nearby residents were exposed to contaminants migrating from the site, ATSDR evaluated the environmental and human components that lead to human exposure. The pathways analysis consists of five elements: a source of contamination, transport through an environmental medium, a medium of exposure, a route of human exposure, and an exposed population.
ATSDR categorizes an exposure pathway as a completed or a potential exposure pathway if the exposure pathway cannot be eliminated. Completed pathways require all five elements exist and indicate that exposure to the contaminant has occurred, is occurring, or may occur. Potential pathways are those in which one of the five elements is missing, but could exist. Potential pathways indicate that exposure to a contaminant could have occurred, could be occurring, or could occur. An exposure pathway may be eliminated if at least one of the five elements is missing and will never be present. The discussion that follows incorporates the pathways that were relevant to the site prior to the removal actions that were completed in 1996 (Table 13). Currently, there are no known routes of human exposures and future exposures to contaminated media were eliminated during the removal activities at the site. The toxicological significance and public health implication of exposure to the contaminant concentrations detected prior to the removal actions at the site are discussed in the Public Health Implications Section of this document.
A. Completed Exposure Pathways
Surface Soil Pathways
In the past, exposures to contaminated on-site and off-site surface soil is believed to have occurred at the site and the Riverside neighborhood. Exposures could have occurred to on-site workers, to children and adults who entered the site for recreational purposes, and to residents exposed to contaminated off-site soil. Evidence suggests that on-site workers exposed to lead may have transported the lead on their clothes to their homes; this practice could have resulted in exposures to family members. The off-site surface soil could have also been contaminated through surface water runoff from the site and/or through air/wind.
On-site: Surface soil samples collected in 1991 indicated the presence of one pesticide, PCBs, and three metals. Children and adults who gained access to the site for recreation were exposed to the on-site surface soil contaminants through inhalation, dermal contact, or incidental ingestion. In addition, youths and adults who worked on the site were exposed to the contaminants through the same routes of exposure. Lead exposures were the primary concern for exposures because the on-site soil concentrations exceeded 10,000 ppm and children were at greater risk of exposures to lead contaminated soil through ingestion because of their frequent hand/mouth actions.
The Occupational Safety and Health Administration (OSHA) issued several citations that indicated that site employees were exposed to lead at levels above the Permissible Exposure Limit (PEL) (OSHA, 1989). Workers were exposed to lead through inhalation, dermal contact, and ingestion during the bead blasting operations and while cleaning their clothes with a vacuum that lacked a HEPA filter required to avoid dispersing lead dust into the air. In addition, the worker's change area (where they vacuumed their clothes) doubled as a lunchroom. Employees entering the lunchroom facilities were not required to remove surface lead from their work clothes.
From conversations with OSHA's Area Director in Denver, Colorado (ATSDR, 1992a) and one of the petitioners (ATSDR, 1992b), ATSDR was informed that the number of Hansen employees fluctuated from approximately 9 to 15 at one time. According to the OSHA Denver official, five employees were involved in the OSHA citations against Hansen Containers. It is not known whether these employees were residents of the Riverside community.
Off-site: Residential soil sampling revealed the presence of pesticides, PCBs, semi-volatile organic compounds, PAHs, metals, and dioxins and furans. Children and adults may have been exposed through inhalation, dermal contact, or incidental ingestion of soil. The practices for vacuuming clothes and eating in the same area at the facility resulted in direct and indirect exposures to site workers. It is also possible that these occupational exposures resulted in secondary exposures to other adults and children in the community if the employee transported contaminants on their clothes to their homes. In general, with the exception of metals, the off-site contaminants were identified at considerably lower levels than those identified in on-site samples.
Air Pathways
In the past, children and adults who entered the site for recreational purposes or on-site workers are believed to have been exposed to on-site airborne contaminants. Exposures through inhalation of the contaminants identified in the on-site air could have resulted from the incineration process or from the wind carrying contaminants identified in soil. On-site air monitoring was limited to two days of sampling in 1989; collected from the parking lot and from an area approximately 100 meters downwind from the incinerator. Sampling analyses identified the presence of ethylbenzene and xylene.
Additionally, gaseous and particulate airborne contaminants identified on-site may have migrated off-site through the air pathway from the incineration process and this could have resulted in inhalation exposures. Exposures to gaseous and particulate airborne contaminants from the incineration process ceased in 1991 when the facility closed.
B. Potential Exposure Pathways
Soil Gas contaminants migrating off-site
A potential for migration of organic soil gases from the site to residences in the Riverside community existed in the past; however, we cannot evaluate this possibility due to the lack of data. Figure 5, Appendix A, shows the organic soil gas "hot spots" that were detected on-site in 1991. The two more prominent spots were located at the fence line on the west side of the facility. In these spots, organic soil gas contamination ranged from over 5 ppm to over 50 ppm of organic soil gas; however, the organic gas or gases could not be identified. Potential exposures to soil gases were eliminated when the site remediation was completed.
On-site Radioactive Material
Children and youths, who gained access to the site for recreation, could have been exposed to on-site radiation. In addition, youths and adults who worked on-site may have also been exposed to on-site radiation levels. The toxicological significance of exposure to the levels detected on-site will be discussed in the Public Health Implications Section.
C. Eliminated Exposure Pathways
Waste Material
ATSDR believes that past exposures to waste material on-site were unlikely. The soil at the site was removed as part of the remedial process and the ash that was contained in drums at the site prior to the remediation activities were removed as part of the removal actions; therefore, this pathway is eliminated.
On-site Subsurface Soil
Exposures to soil at the depths sampled are very improbable; therefore, this pathway is eliminated. The samples were collected with a backhoe at approximately 7 and 15-20 feet depths, with actual sampling depths from 3 - 20 feet (Ecology and Environment, 1991b).
Groundwater
The Riverside Community is served by municipal water and there are no known private drinking water wells in the community; therefore, this pathway is eliminated.
ATSDR classifies the Hansen Containers Site as a past Public Health Hazard because of exposures to contaminants detected at the site. For people who live in the Riverside community, the most likely pathways of exposure to contaminants of concern are from: (1) past contact with on-site surface soil, (2) contact with off-site (residential) surface soil, and (3) breathing airborne on-site and off-site substances. The public health implications of these exposures are discussed in this section:
A. Toxicological Evaluation
The toxicological implications of contaminants of concern identified in the environmental contamination section of this document are evaluated by: (1) considering the types and concentrations of contaminants detected in the environmental media (air, water and/or soil); (2) the routes (i.e., inhalation, ingestion, or dermal contact) by which humans may be exposed to those contaminants; and, (3) how often (frequency) and how long (duration) exposure to those contaminants occurred. The toxic effects of a contaminant and the severity of those effects are related to the amount (dose) of a contaminant that a person may be exposed to on a daily basis and to the frequency and duration of the exposures.
Public health concern is greater for people exposed to contaminants at levels above established health guidelines for a critical length of time. Health-based guidelines values are developed for contaminants commonly found at hazardous waste sites (see Appendix C). Examples of health guidelines are the ATSDR's Minimal Risk Levels (MRLs) and the EPA's Reference Doses (RfDs). The MRLs and RfDs are estimates of daily dose of a contaminant below which is unlikely to produce adverse health effects. MRLs are usually developed for ingestion and inhalation, and also for acute exposures (those less than or equal to 14 days), intermediate exposures (those of 15 to 364 days), and chronic exposures (those of 365 days or more). ATSDR presents many of the health guidelines in Toxicological Profiles, that provide chemical-specific information on health effects, environmental transport, and human exposure to the particular contaminant.
ATSDR also uses Environmental Media Evaluation Guides (EMEGs) and Cancer Risk Evaluation Guides (CREGs) as comparison values that correspond to a 1 X 10-6 level of cancer risk. ATSDR's comparison values are media specific concentrations used by health assessors to select environmental contaminants for further evaluation; they are not used as predictors of adverse health effects or for setting cleanup levels. Media concentrations below a comparison value are unlikely to pose a health threat; however, it does not necessarily follow that a media concentration above a comparison value represents a health threat. The potential for adverse health effects is related to the magnitude and duration of exposure, rather than to the environmental concentration alone.
Exposure by ingestion
Lead in residential surface soil
Lead is a naturally occurring bluish-gray metal found in small amounts in the earth's crust. It has not characteristic taste or smell. Its most important use is in the production of some types of batteries, it is also used to make ammunition, some kinds of metal products (i.e. pipes, solder, sheet lead), and in ceramic glazes. Until 1991, lead was used as an additive in gasoline. Lead was also used in lead-based paint in the past. Throughout the United States, lead from a variety of sources has been deposited on surface soil; most notably from homes with flaking lead-based paint and the use of leaded gasoline in vehicles (ATSDR, 1992f). Soil concentrations are typically expressed in mg/kg, also known as parts per million (ppm). Soils next to houses with exterior lead-based paints may have lead levels as high as 10,000 ppm (ATSDR, 1990). The levels of lead in soil next to well traveled roadways may range from 30 to 2,000 ppm. The background levels of lead in soil in the Eastern U.S. range from less than 10 ppm to 300 ppm and average 17 ppm; in the Western U.S. they range from <10 ppm to 700 ppm and average 20 ppm (ATSDR, PHAGM, 1992).
Tables 11 and 12 present the concentrations of lead detected in residential soil samples. The distribution and concentration of lead in off-site soils suggest that there is no widespread lead contamination in the Riverside community and the Hansen site may not be the major source of the lead in the neighborhood soils. Almost 94% of all samples (120 of 128) contained less than 300 ppm lead, which places them within the range of most U.S. residential soils (Mielke, 1993). Five samples contained between 301 and 600 ppm lead, which is still within the normal range for soils in the Western U.S. (from less than 10 to 700 ppm). Only 3 of the 128 soil samples were detected at concentration beyond the normal range for this part of the country, and none of these samples were in areas frequented by local children. Both the distribution and the relative scarcity of these "warm spots" greatly reduce the potential for high-level lead exposure in local children. (Note: A relatively high concentration may pose no more risk than a lower concentration if the potential for exposure is proportionately less). The soil lead levels were low in the areas that local children most frequent, such as the Headstart Center and the empty lot on Crawford Avenue. Therefore, the available soil data suggest that the concentrations of lead detected in the residential soils do not pose a health hazard to sensitive members of the community.
No ATSDR Minimal Risk Level, EPA Reference Dose, or any other comparison value has been established for lead; nor has any biological need for this metal been identified. The principal route of exposure is food, but excess exposure and toxic effects are usually the result of other, presumably preventable, environmental exposures (R.A. Goyer, 1991). Lead toxicity is usually the result of occupational exposure via inhalation for adults, and ingestion of contaminated soil, dust, or paint chips for children.
Public health efforts to minimize environmental exposures to lead are steadily increasing. The concerns with environmental exposures to lead stem from evidence that children and developing fetuses are especially sensitive to lead (CDC, 1991; ATSDR, 1992f; Rothenberg et al., 1992). The results of some studies suggest that lead detected in the blood at low levels (10 to 25 micrograms per deciliter or µg/dL) may be related to delayed mental development, reduced intelligence quotient (I.Q.) scores, poor attention span, speech and language handicaps, and impaired hearing (CDC, 1991; ATSDR, 1992f); however, the evidence for such a relationship is mixed. Other studies suggest that, when all variables are properly controlled, there is no statistically significant association between blood lead levels below 30 µg/dL and I.Q. deficits or academic performance (M.A. Smith et al., 1983; McMichael et al., 1988). In children, blood lead levels of 40 to 60 µg/dL are associated with peripheral neuropathy, while levels of 80 to 100 µg/dL may be associated with acute nephropathy, anemia, and overt encephalopathy (Goyer, R.A.1991). In adults, overt encephalopathy may also be seen, but at higher blood-lead levels (100-120 µg/dL); at lower levels, hypertension (30 µg/dL) and chronic kidney damage (60 µg/dL) may occur. The health effect from lead toxicity will depend upon the form of lead, the magnitude and duration of exposure, and the sensitivity of the individual. The greatest determinants of sensitivity to lead toxicity are age and sex.
Exposures to high levels of lead in soil can result in elevated concentrations of lead in the blood. However, blood lead levels will not correspond to soil lead unless: (1) the lead is present in a bioavailable form at high enough levels (>500-1000 ppm; CDC, 1985); and, (2) the contaminated soil enters the body in sufficient amounts. Thus, the measures of environmental contamination are not indicators of human exposure. In fact, it is possible for blood lead levels to be in the "normal" range in spite unusually high levels detected in soil if the contaminated soil is not consumed or ingested or the lead is not in a bioavailable form. Therefore, blood lead screening is the only indicator of whether exposures are occurring at levels of health concern.
During September 23-27, 1991, ATSDR, in collaboration with the Mesa County Health Department, EPA Region VIII, Grand Junction Fire Department, Concerned Citizens Resource Association, and the petitioners conducted blood-lead screenings for the residents of the Riverside Community and other people living outside of the neighborhood who were interested in the screening. A total of 287 blood samples were collected and analyzed. The results support the conclusion that residents are not being exposed to lead at levels of health concern. The correlation between the levels of lead detected in the blood of the children and residential soil is very poor. The actual blood lead levels in children were generally quite low. The majority of the young children (5 yrs old or younger) living in this community had blood lead levels that were well below the national average of 16 µg/dL (NHANES II, 1984). Approximately 90% of the Riverside children tested had levels below 10 µg/dL, and none had blood levels exceeding 17 µg/dL. By contrast, in a national survey of blood lead levels in the U.S. (NHANES II, 1984), only 25% of children in the 6 mo-5 yr age group had blood lead levels at or below 10 µg/dL, while approximately 35% had blood leads exceeding 17 µg/dL. Fully half of the national sample had blood leads in the range of 11-19 µg/dL, compared to less than 12% of the children in the Riverside community. Thus, we do not believe that children in the Riverside Community were or will be adversely affected by existing soil lead levels.
Of the 41 young children for whom matching soil lead data are available, only three lived where the level of lead in soil exceeded 292 ppm. The blood lead levels of these children (12 µg/dL, 5 µg/dL, and below the detection limit of 4 µg/dL) did not reflect exposure to lead at levels of health concern. No matching soil data were available for the highest blood lead value measured. All of the people living outside Riverside who participated in the blood lead screening program had blood lead levels below 10 µg/dL. Only eight of the out-of-town participants were 5-years old or younger, and only two of these children had detectable levels of lead in their blood (i.e., 4 and 8 µg/dL).
Arsenic and other metals in residential surface soil
Other metals detected in residential soils at the Riverside Community include aluminum, arsenic, barium, cadmium, chromium, copper, magnesium, manganese, mercury, vanadium, and zinc (Table 7, Appendix B). In general, the range of concentrations found in Riverside residential soil samples was typical of normal soils in the Western U.S. (ATSDR, PHAGM, 1992). With the possible exception of arsenic, even the highest reported levels of these metals is not expected to result in any adverse health effects in children or adults.
If young children (especially those exhibiting pica-soil behavior) regularly ingest soil from the residential area containing the highest concentration of arsenic of 222 ppm, exposures would exceed EPA's chronic oral reference dose (RfD) of 0.0003 mg/kg/day. This RfD corresponds to an estimated daily arsenic intake of 3 µg/day for a 10-kg child and 21 µg/day for a 70-kg adult. The average daily intake in the U.S. was estimated at 5 µg/day (HSDB).
Although the RfD is a dose level considered to be "safe", it does not necessarily follow that any dose that exceeds the RfD is considered to be unsafe. The RfD is based on a lifetime (70 years) of exposure, contains built-in safety factors, and must be interpreted in the context of actual or probable exposure scenarios to be practical. For example, based on a chronic oral RfD of 0.0003 mg/kg/day and an ingestion rate of 5000 mg/day, the safe level of soil arsenic for a 10-kg pica child would be 0.6 ppm. However, the concentration of arsenic in soils of the U.S. normally range from 0.1 to 97 ppm in the west and <0.1 to 73 ppm in the east - with averages of 7 ppm and 7.4 ppm, respectively (PHAGM, 1992). Thus, based on EPA's reference dose, many presumably "uncontaminated" soils in the U.S. would contain too much arsenic to qualify as "safe" for a pica child. Such apparent inconsistencies are not uncommon when a series of highly conservative assumptions are compounded in a single numerical estimate; therefore, the numbers must be interpreted in a practical context before they are applied to real life situations.
In the case of arsenic a classical threshold of toxicity exists for non-carcinogenic and carcinogenic effects; therefore, these effects would be expected to occur only when the dose exceeds a given level. When considering these threshold effects, a daily arsenic intake of 400 µg/day may be considered safe (Stohrer, 1991). The maximal dose to a 10-kg child eating 200 mg/day of the highest level of arsenic detected in residential soil would be only 40 µg/day (one tenth the safe dose of 400 µg/day). However, the actual potential for exposure is much less because of the way arsenic concentrations are distributed.
The average concentration of arsenic detected was 15.5 ppm, with a median of 5.4 ppm. Only 5 of 128 residential soil samples contained arsenic at levels from 110-222 ppm that exceeded the normal range found in soils of the Western U.S. Over 96% (125 of 128) of all the Riverside residential soil samples contained less than 100 ppm arsenic, and almost 86% (110 of 128) contained less than 20 ppm. Overall, the arsenic content of Riverside soils is comparable to that of other towns used as controls in arsenic contamination studies (NRC, 1991, pg. 211). Most importantly, the samples collected at the Headstart Center and the empty lot on Crawford street (where children may be expected to play) did not contain arsenic at levels of health concern, even for pica children.
Organic compounds in residential surface soil
Riverside community residential soils were sampled and analyzed for polychlorinated biphenyls (PCBs), various pesticides, polyaromatic hydrocarbons (PAHs) and dioxins. Sampling analyses identified the presence of PAHs, pesticides, and dioxins at very low levels (Tables 8, 9, and 10). Human and animal studies indicate that exposures to the contaminant concentrations detected in residential soils are several orders of magnitude lower than those expected to cause any adverse health effects.
Contaminants in on-site soil
While evaluating exposures, ATSDR estimates that the remediation of the site eliminated the potential for present and future exposures to the contaminants identified in on-site soil prior to the remediation. Due to the lack of data from the past, we cannot evaluate past exposures to site-related contaminants and potential health effects. The concentrations of arsenic detected in on-site surface soil were within the normal range for Western soils. The highest concentration of arsenic detected in on-site soil (40 ppm) was lower than it was in residential soil (222 ppm). The CREG for arsenic is 0.5 ppm; this number reflects the official assumption of a zero-threshold dose-effect relationship; however, the carcinogenic effects of arsenic exhibit a quantifiable threshold (Stohrer, 1991). Based on the data from the 1991 sampling rounds, we do not expect adverse health effects from past exposures.
As part of the 1991 sampling rounds, lead was detected in on-site surface soil samples at levels exceeding 10,000 ppm (Table 3, Appendix B). However, in the absence of data from the past, it is not known whether this level of lead in soil had any adverse effect on the site workers, or on children or adults who entered the site for recreational purposes. The blood lead screening conducted in 1991 indicated that the levels of lead in children were within the national norm; however, this information does not enable us to evaluate the likelihood or possible extent of exposures in the past. The most important finding was that soil lead levels were low in the areas that local children most frequent, such as the Headstart Center and the empty lot on Crawford Avenue. Therefore, the available data suggest that the concentrations of lead detected in residential soils do not pose a health hazard to the community. Additionally, the remedial actions finalized on the site eliminated the potential for present or future exposures to on-site lead at levels of concern.
The levels of chlordane and PCBs detected in on-site surface soils (Table 1) were somewhat higher than the respective CREGs (comparison values that reflect the assumptions of a 70-yr (lifetime) exposure and no threshold of effect). However, neither of these assumptions apply to these compounds at the site because the site operated less than 40 years. Chlordane and PCBs inhibit intercellular communication in cell culture and enhance the production of hepatocellular carcinomas in mice through an epigenetic mechanism that apparently involves promoting effect on preexisting abnormal cells (Williams and Weisburger, 1991). However, the mechanisms involved would imply a threshold of effect for both chemicals.
High doses of PCB exposures may have immunosuppressive effects in humans and animals (Dean and Murray, 1991). A 15-yr study did not reveal excess mortality or cancer incidence in 142 Swedish capacitor manufacturing workers (Ellenhorn and Barcelloux, 1988b, p. 955). While the study may be considered too small to detect subtle changes in cancer rates, there is no other compelling evidence that PCBs cause cancer in humans. Jaundice has been reported to occur in residents of homes recently treated with chlordane, but occupationally-exposed workers appear to be free of chlordane-related adverse health effects (Santolucito and Nauman, 1992). In the opinion of ATSDR, the levels of chlordane and PCBs in on-site soils do not represent a health hazard to Riverside residents in the past. The remedial actions eliminated present and future exposures.
Exposure by inhalation
On-site and off-site airborne contaminants
Air monitoring conducted in 1989 from the incinerator plume and the parking lot scan identified releases of ethyl benzene and xylene. However, the facility ceased operations in 1991, this prevented further exposures from the site operations. The toxicological data do not indicate adverse health effects associated with exposures to ethyl benzene and xylene. Analyses of the residential soil data did not identify elevated levels of organic compounds (i.e. PCBs, PAHs, or pesticides); therefore, the airborne contaminants did not accumulate to the extent that adverse health effects would have resulted.
Site workers may have been exposed through inhalation of lead and other chemicals during the bead blasting operation and while cleaning their clothes when the facility was operable (OSHA, 1989). However, no data are available from the past to better characterize this pathway; therefore, we cannot evaluate health effects that may have been associated with exposures.
As part of the September 1992 remedial actions, the EPA/OSC who was working at the site noted strong mercaptan odors. Similar odors were reported by Riverside residents. The mercaptan odors appear to be associated with the removal activities at the site. Methyl mercaptan is a colorless gas with a smell similar to a rotten cabbage. It is a natural substance present in human and animal tissues. It occurs in small quantities in a variety of vegetables, such as garlic and onion (Clayton, G.D. and F. E. Clayton, 1981). It is released from decaying organic matter in marshes and is present in the natural gas from certain regions of the United States. Methyl mercaptan is also manufactured for use as a food additive, in pesticides, in jet fuel, in the plastics industry, and in making poultry feed (ATSDR, 1992h). Little is known about what happens to methyl mercaptan after it is released to the environment or about the potential health effects from exposures (specifically: human health effects through inhalation). If gaseous methyl mercaptan is released on land, it adsorbs strongly to the soil. In the atmosphere, methyl mercaptan will be oxidized by photochemically generated hydroxyl radicals. The half-life for this reaction is 11.6 hr (ATSDR, 1992h).
Irritation of mucous membranes of the nose, respiratory tract, skin, and eyes have been reported by workers exposed to mercaptans in general. Measurements in occupational settings such as wood-pulp mills have revealed methyl mercaptan levels below 4 ppm. The only human evidence of neurological and hematological effects of occupational exposure to methyl mercaptans comes from a study of a 53 year-old black male who died after one week of emptying methyl mercaptan tanks (exposure levels not known). The man was hospitalized in a coma and died 28 days after admission. This study was based on an occupational exposure and does not necessarily represent environmental exposures to methyl mercaptan. Exposures to methyl mercaptan at 1,200 ppm have not induced coma in rats while exposure of rats to 1,400 ppm for 15 minutes have resulted in lethargy and coma (ATSDR, 1992h).
Methyl mercaptan can be smelled and recognized in air by humans when it is present at levels as low as 1.6 ppb (1.6 parts of methyl mercaptan in one billion parts of air; equivalent to 0.0016 ppm). During sampling at the site, organic vapors were occasionally detected at six on-site stations at levels ranging from 0.1 to 3.0 ppm with an average of 0.4 ppm. It is, therefore, possible to say that the exposures of those people who actually smelled the mercaptans on other occasions may have been as high as 3.0 ppm. This is a conservative scenario for two reasons: 1) the maximum value, 3.0 ppm, was detected on-site in a drum removal area, not in the residential area of the Riverside community. We have no data on the methyl mercaptan levels in the residential areas; however, one would expect the methyl mercaptan levels in the community to be much lower than 3.0 ppm; and, 2) while the average of the detections is 0.4 ppm, half of all detections are equal to 0.2 ppm or less.
Given the short duration and the expectedly low levels of methyl mercaptan exposures to Riverside residents, no adverse health effects are anticipated from the discussed exposures.
External exposure to radioactive material
Hansen Containers was permitted to store low-level radioactive waste. During the initial stages of the remediation process, sources of low level radiation, primarily in the form of beta and gamma emitters, were detected in various drums containing an ash-like material. Health concerns associated with exposure to those contaminants are related to the risk of cancer (such as leukemia in children). Thirty drums containing yellow cake were stored in a semi-trailer next to an occupied house (ATSDR, 1991a). Children and youths who gained access to the site and on-site workers may have been exposed to on-site radiation. However, the radiation sources were confined to areas of the site that were inaccessible and exposures were not expected to be significant; therefore, not of public health concern. In addition, the sources of radiation were removed as part of the remedial activities at the site and the potential for present and future exposures were eliminated.
As part of the 1991 off-site soil sampling, elevated radiation readings were noted at three locations on West Main Street. The highest reading encountered was 0.15 mR/hr above background (Ecology and Environment, 1992a), which would be of public health concern for exposure over the long term. An association of off-site radiation levels with potential releases from the site are unlikely due to the distance from the facility. DOE remediated off-site areas under the Uranium Mill Tailings Remedial Action (UMTRA) program; therefore, the present or future exposures were eliminated.
B. Health Outcome Data Evaluation
Blood-lead screening
On September 9, 1991, ATSDR issued a Public Health Advisory to inform other agencies and the community of concerns noted as part of the scoping visit for the site. The grounds for the advisory were: (1) the presence of lead at levels of concern at the facility (residential soil levels were not known at that time); (2) evidence of contact with lead-contaminated soils due to the fact that the site was unrestricted and the concern that site-related contaminants may have migrated off-site; (3) the probability of adverse health effects due to exposure to on-site lead; and, (4) that no actions (such as restricting site access) were in progress to reduce or eliminate exposures to site contaminants (ATSDR, 1991f).
As a result of the recommendations made in the ATSDR Public Health Advisory, CDPHE, in cooperation with ATSDR and the Mesa County Health Department (MCHD), conducted a community census and blood lead testing program in the Riverside community from September 16-27, 1991. The community census revealed that 148 of 172 home sites in the area were occupied. Census data were obtained from 139 of the 148 occupied homes. Two households refused to provide information and personal contact was not achieved at seven homes; we distributed fact sheets providing information about the blood-lead screening program to these residences. Conversations with neighbors revealed that no children lived in those residences. Based on the census information, we identified and scheduled for blood testing 73 children under 6 years old (9 to 71 months old) (ATSDR, 1991h).
From September 23 - 27, 1991, blood samples were collected from 287 adults and children in the area (Table 14, Appendix B). Of the blood samples taken, six children (11.3%) under 6 years of age and two children (2.3%) 6 to 18 years old had blood lead levels at or above 10 micrograms of lead per deciliter of blood (µg/dL). The current Centers for Disease Control and Prevention (CDC) guidelines recommend that children with blood lead levels ranging from 10-14 µg/dL be screened every 3-4 months until consecutive blood lead levels are acceptable (CDC, 1991). The results of this screening were consistent with the overall low levels of lead found in Riverside neighborhood soils. CDPHE incorporated the people who exhibited slightly elevated blood lead into a blood lead surveillance program and conducted follow-up actions of these individuals 11 and 14 months after the initial testing and again in September 1994 - the results indicated that the blood lead levels were not a public health concern.
Lead deposited in dust and soil becomes a long-term source of lead exposure in children because it does not readily dissipate, biodegrade, or decay in the environment (ATSDR, 1988; ATSDR, 1992f). On the other hand, lead is cleared from blood to bone, other tissues, and urine in a fairly short period of time. The half-life(3) of lead in human blood is about 30 days. This means that a lead level detected in people's blood is an indicator of recent exposure. In other words, the blood lead screening conducted in 1991 does not reflect lead exposures that may have occurred several years before, as was the case for workers on site.
Currently, there are no routes of exposure because the contaminants were eliminated as part of the removal actions at the site. Therefore, no current or future exposures or health effects are anticipated.
State and Local Health Data
To address one community member's concern about cancer, ATSDR researched the available area data for cancer prevalence in the area. The data for Grand Junction are available down to the ZIP code; Riverside is a small component of Grand Junction's ZIP code (81505); however, data specifically for the Riverside community are not available. Additionally, the Colorado Central Cancer Registry does not report precise information at the zip code level. Therefore, we cannot evaluate data appropriate for the Riverside community.
We also contacted the local health departments for data pertaining to health outcomes related to the Hansen Containers facility. These agencies did not have site-specific health data to report.
C. Community Health Concerns Evaluation
The EPA conducted Community relations programs throughout the removal actions at the Hansen Site. The removal actions were intended to stabilize or clean up the site. The community were informed of the removal actions as they occurred and the final Community Relations Plan was completed in May 1993. The document provided education to the community about the objectives and techniques used during the remaining investigation and clean up of the site. The EPA on scene coordinator also interacted individually with the local residents and officials and distributed a fact sheet during the site clean up.
As part of the Public Health Assessment Process, ATSDR releases the health assessment to the community for review and comments. This period also serves the community to provide additional concerns related to the site. The PPHA was released for public comment in October 1996; ATSDR did not receive community health concerns during that time. Therefore, in this subsection, we address each community health concern (in bold) with a response immediately following the concern. However, these were concerns that were presented to ATSDR prior to the completion of the removal actions. With the successful completion of the removal actions, we have not received or anticipate any community health concerns related to the site.
In the remainder of this section, ATSDR addressed the community concerns expressed as part of the petition process (in bold) with a response immediately following the concern:
What are the health effects from dermal, ingestion, and inhalation exposure of children to lead, pesticides, volatile organic compounds, and other on-site contaminants?
Adverse health effects associated with exposures to lead in children are not expected based on the available environmental data and the results of blood lead screening of Riverside residents. However, it is not possible to rule out the possibility of adverse health effects occurring for children who may have frequented the facility prior to its closure in 1991 and the site restriction. Any possible health effects depend on the degree of individual exposures and those cannot be reliably estimated.
What are the health consequences of lead transport on worker's clothes from the facility to their respective homes with the potential exposure to other family members?
Workers were exposed to lead dust during the bead blasting operations and probably transported lead to their homes on their clothing. However, lack of data from the past makes it impossible for us to adequately evaluate this concern. Young children and developing fetuses are especially sensitive to lead. The results of some studies suggest that lead detected in the blood at low levels (10 - 25 micrograms per deciliter or µg/dL) may be related to delayed mental development, reduced intelligence quotient (I.Q.) scores, poor attention span, speech and language handicaps, and impaired hearing. However, other studies show no deficit of I.Q. with blood levels below 30 µg/L, if all variables are controlled.
What are the health consequences of dermal, inhalation, and ingestion exposures of workers to lead in the occupational setting of the facility? In addition, it has been reported that adolescents of 12 and 13 years of age also worked at the Hansen facility (ATSDR, 1991c).
The health consequences of exposures to lead and to other substances are dependent on the amount (dose), frequency, and duration of exposure of the particular substance. These data are needed to evaluate potential health effects from exposures. Unfortunately, no exposure data from the past were available for ATSDR to review; therefore, we cannot evaluate past occupational exposures.
The following are general comments related to health effects associated with lead exposure: Acute toxicity is unusual, since lead is a relatively insoluble, cumulative substance. However, chronic exposure to high levels of lead may result in kidney damage, anemia, peripheral neuropathy, and encephalopathy. There is also evidence that exposures to high levels of lead may reduce sperm count and increase the probability of spontaneous abortion. Increased blood pressure (hypertension) is the most sensitive adverse health effect in adults, especially in middle aged men. Fetuses and young children (6 years old or younger) are especially vulnerable to lead toxicity, due to greater absorption, immature natural defenses, and that lead crosses the placenta in the maternal blood. Adolescents are less susceptible to toxic effects than younger children but not as resistant as adults.
What are the health consequences of the transport of contaminants from the facility to neighboring houses through runoff water used to flush trucks and trailers on-site?
The soil sampling data collected from the neighborhood yards do not indicate accumulation of rinse water contaminants. In addition, on-site soil samples collected from an area closest to the neighborhood did not contain elevated levels of contaminants. Therefore, no adverse health effects from surface water runoff are expected.
What health effects are associated with: 1) inhalation of particulates and gases from the incinerator operations; 2) dermal exposure to particulates (separate particles) and polymers (numerous compounds) from the site and at the site; and, 3) inhalation of dusts generated during the process of emptying the barrels?
Exposures to particulates, polymers, and dust may have occurred from the release of airborne contaminants during the incineration process at the site; however, we cannot identify the likely hazards associated with this concern because we do not know the chemical makeup of the emissions. Some community members reported episodes of nausea, headaches, general fatigue, nosebleeds, allergies, and burning eyes and nose. While these conditions are biologically plausible responses of exposure to airborne contaminants, we cannot issue a statement about the extent/severity of actual or potential adverse health effects.
What health effects, if any, can be expected from exposures to contaminants through ingestion of contaminated garden produce?
No adverse health effects are currently anticipated from eating garden vegetables grown in neighborhood yards. It is possible that produce may have been contaminated in the past, as a result of deposition of contaminated dusts on the surface of vegetation during the incineration process at the facility. However, there is no information available from that period that would allow ATSDR tp evaluate exposure or the possibility of adverse health effects. Since the facility closed in 1991, contamination from site operations ceased.
A small number of residential soil samples contained slightly elevated levels of metals. Lead uptake from soil in plants is highly unlikely because it is typically immobilized or tightly bound in soil. Studies have shown that some metals such as zinc, cadmium, manganese, and selenium are taken up, to some extent, by plants. Uptake of some metals may be considerable in lettuce, spinach, and other leafy vegetables, but has been reported to be low in tomatoes.
Is there an association between the past episodes of nausea, headaches, general fatigue, nosebleeds, allergies, burning eyes and nose among some Riverside residents and the operation of the Hansen container facility?
The association is possible but it can not be determined with certainty because of the lack of data to indicate the amount of airborne contamination in the past. The health conditions outlined above are biologically plausible responses of exposure to airborne contaminants; however, they are also non-specific symptoms that could have a number of other causes unrelated to Hansen Containers.
Is there a connection between the cancer cases in the Riverside community and the operation of the Hansen container facility?
We cannot accurately evaluate this community health concern because: 1) the data for Grand Junction are available only at the ZIP code level and Riverside is a small component of Grand Junction's ZIP code (81505); and, 2) the Colorado Central Cancer Registry does not report precise information down to that level. The available data indicate that the identified site-related contaminants were not present at levels that would represent a cancer hazard.
ATSDR classified the Hansen Containers site as a past public health hazard. This classification was based on the fact that: in the past, children and adults had unrestricted access to the lead contaminated soil on the Hansen site and former site workers were exposed to lead from the bead blasting operations at levels that exceeded OSHA's permissible exposure limits. However, ATSDR was unable to evaluate past exposures or adverse health effects in workers or Riverside residents which may have resulted during the operation of the facility because there were no data that adequately characterized those exposures. Currently, Hansen Containers is classified as a no public health hazard because: 1) facility operations ceased in 1991; 2) site access was restricted in January 1992; and, 3) removal activities were completed in 1996.
Contaminants previously identified as being of concern included: lead, polychlorinated biphenyls (PCBs), aldrin, dieldrin, and various volatile and semi-organic compounds. Lead was considered the primary contaminant of concern from the Hansen Containers facility due to the fact that the site was unrestricted and children and adults could have been exposed to lead at levels of health concern. ATSDR reviewed the data collected during and after the removal activities. The removal activities eliminated the contaminants of concern; therefore, no exposures are occurring or are expected to occur in the future.
After ATSDR's initial site scoping in 1991, a Public Health Advisory was issued to inform the community and local and federal agencies about conditions that may pose an urgent public health hazard. The health advisory focused on the fact that the site was unrestricted, and ATSDR's concern about health effects associated with exposures to lead. As a result of the Health Advisory, CDPHE in cooperation with ATSDR and other federal and local agencies conducted blood lead screening for children and adults in the area. This information was needed to enable us to better characterize potential health effects from lead exposures. The screening identified a small number of children under 6 years old with slightly elevated blood lead levels. CDPHE incorporated the people with slightly elevated blood lead into a blood lead surveillance program. After follow-up of these individuals 11 and 14 months after the initial testing and again in September 1994, the results indicated that the blood lead levels were not a public health concern. Additionally, off-site residential soil samples were collected and analyzed; the results indicated that exposures to these soils did not present a public health hazard.
The community expressed concerns about health effects associated with exposures to site-related contaminants. Specifically, they were concerned about: 1) health effects that children and adults may experience from exposures through incidental ingestion, inhalation, or dermal contact with on-site and off-site contaminants; 2) lead exposures to site workers and the potential for exposures to family members due to lead transport on the worker's clothes; 3) transport of contaminants from the facility to neighboring houses through runoff from the site; 4) dermal and inhalation exposures to dust carried off-site by surface runoff; 5) inhalation of particulates and gases from the incinerator and from smoldering drums leaving the incinerator; 6) dermal exposure to particulates and polymers; 7) exposure to dusts generated during the process of emptying the drums; and, 8) exposure to contaminants through ingestion of contaminated garden produce. In addition, one resident expressed concern about the incidence of cancer in the community.
ATSDR could not evaluate exposures from the past due to the lack of data that would adequately enable us to characterize potential past exposures. We evaluated the health effects from exposures to lead at the site and the Riverside community and conducted blood lead screening for 287 individuals in 1991. The blood lead screening identified a small number of people with slightly elevated blood lead levels. CDPHE, in cooperation with ATSDR, conducted follow-up actions with the individuals with slightly elevated blood levels and the results indicated that no adverse health effects occurred. The site remediation was completed; therefore, present and future exposures were eliminated.
Data inadequacies discovered during the preparation of this document include: 1) no air monitoring data from the past are available to enable us to estimate exposures, specifically, during site operation of the incinerator; 2) the potential migration of soil gases from the site to residential areas was not been addressed; and 3) while organic soil gas sampling revealed on-site organic vapor levels ranging from 0 to 100 ppm, the identity of the organic gas or gases was not reported.
Cease or Reduce Exposure Recommendations
1. Review the remediation data to ensure that the site remedial actions were completed and the present and future exposures were eliminated or minimized.
Health Activities Recommendation Panel (HARP) Recommendations
In accordance with the Comprehensive Environmental Response Compensation, and Liability Act (CERCLA) of 1980, as amended, ATSDR evaluated the Hansen Containers Site, Grand Junction, Colorado, for appropriate health follow-up actions. The panel offered the following recommendations:
HARP determined that the Riverside community residents needed assistance in understanding the pathways by which they have or may have been exposed, the potential for such exposures, and the potential adverse health effects of such exposures. Therefore, HARP recommended community and health professionals education. CDPHE under a cooperative agreement with ATSDR, implemented the community and health professionals education in this area. ATSDR will evaluate additional remedial actions data for further public health actions as needed.
Public Health Action Plan
Currently, there are no known routes of human exposures and future exposures to contaminated media were eliminated during the removal activities a the site. Therefore, no public health actions are recommended because no human exposures are occurring or are likely to occur in the future.
In order to respond to community concerns, and based on the HARP recommendations, the following Public Health Action Plan was proposed:
The Colorado Department of Public Health and Environment, in conjunction with ATSDR, conducted health education programs for area health care providers and for the Riverside residential community. The program for the health care providers was designed to inform them of the current Centers for Disease Control and Prevention (CDC) guidelines, Preventing Lead Poisoning in Young Children. CDC guidelines recommend that children with elevated blood lead values be screened every 3-4 months until consecutive blood lead levels are acceptable. The program also provided advise to the public health professionals and the local medical community of the nature and possible consequences of exposure to contaminants at the Hansen Containers site. The value of obtaining a complete and accurate exposure history was emphasized. The community health education program provided information about the contaminants of concern at the site.
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