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PETITIONED PUBLIC HEALTH ASSESSMENT

HANSEN CONTAINERS
GRAND JUNCTION, MESA COUNTY, COLORADO

APPENDICES

APPENDIX A: FIGURES

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APPENDIX B: DATA - PUBLIC COMMENT VERSION

SUMMARY

The Hansen Container Company Site (also known as the Layton Brothers Drum Company andthe Rock Mountain Drum Company) was an 11-acre drum recycling facility located on thesouthern edge of the Grand Junction city limits, Mesa County, Colorado. The facilityreconditioned structurally sound drums used to transport chemicals and other materialsfrom the mid-1950's until January 1991 (ATSDR, 1991a). InMarch 1991, two Grand Junction residents petitioned the Agency for Toxic Substances andDisease Registry (ATSDR) to conduct a Petitioned Public Health Assessment of the RiversideCommunity (CCRA,1991).

ATSDR prepared this Petitioned Public Health Assessment and classified the HansenContainer Company site (Hansen Containers) as a past public health hazard. Thisclassification was based on the fact that: in the past, children had unrestricted accessto the lead contaminated soil on the Hansen site. Currently, Hansen Containers isclassified as a no public health hazard because: 1) operations at the facility ceased in1991; 2) site access was restricted; and, 3) remedial activities were completed at thesite in 1996. The site was remediated under a joint effort by the Environmental ProtectionAgency (EPA) and the Department of Energy (DOE). The EPA removed drums and debris thatremained on the site after site closure and stabilized and immobilized the contaminatedon-site soil. DOE removed the stabilized soil and buildings from the site with a programthey manage called the Uranium Mill Tailing Remedial Action (UMTRA) program. These actionseliminated the contaminants at the site. Therefore, exposures to contaminants at the sitewere eliminated.

After ATSDR's initial site scoping in 1991, a Public Health Advisory was issued toinform the community and local and federal agencies about conditions that indicated thatthe facility may pose an urgent health hazard. The health advisory documented that thesite was unrestricted and ATSDR had concerns about potential health effects associatedwith exposures to lead. As a result of the issuance of the Health Advisory, the ColoradoDepartment of Public Health and Environment (CDPHE), in cooperation with ATSDR and otherfederal and local agencies conducted blood lead screening for children and adults in thearea. The information was needed to better characterize potential health effects from leadexposures. The screening identified six children under 6 years old with slightly elevatedblood lead levels. CDPHE interviewed the families of the six children and identifiedseveral factors that could have resulted in exposures: peeling paint in the home,remodeling in the home, pica behavior, possible occupational exposures of a parent, andrecent residence in Mexico. Each family received a written report of their test resultsand health and prevention information in spanish and english. CDPHE also contacted thephysicians of the children with elevated blood lead levels and provided them witheducational materials regarding was to reduce exposures. Two of the children with elevatedblood lead levels were re-tested 11 and 14 months after the initial blood testing and hadno elevated blood lead levels. Since October 1993, CDPHE has had a full-time childhoodblood lead surveillance coordinator in the Disease Control and Environmental EpidemiologyDivision; 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 notidentify elevated blood lead levels.

Contaminants of concern identified at the site included: lead, polychlorinatedbiphenyls (PCBs), polyaromatic hydrocarbons (PHAs), pesticides, radionuclides, and variousvolatile and semi-volatile organic compounds. Lead was considered the primary contaminantof concern to the community. Direct contact with lead contaminated soil or dust (throughincidental ingestion and/or inhalation) were the most likely routes of exposure. Ingestionof lead contaminated soil at the levels detected in the past could result in reducedkidney function, gastrointestinal problems, neurological, reproductive, and hematologicaleffects.

ATSDR identified a past completed exposure pathway for the site while it was operableand unrestricted. Children and adults who accessed the site for recreational purposesand/or site workers may have been exposed to soil and airborne contaminants throughinhalation and incidental ingestion of the contaminated media. Potential exposure pathwaysinclude: 1) secondary exposure through inhalation to lead and other contaminants that thesite workers may have transported on their clothes to their homes; 2) the potential forchildren and adults to be exposed to radioactive material found at the site prior to thesite remedial activities; and, 3) exposures through inhalation of soil gas contaminantsthat migrated from the site to the Riverside neighborhood.

The community expressed concerns about health effects associated with exposures tosire-related contaminants. Specifically, they were concerned about: 1) the health effectsassociated with exposures through incidental ingestion, inhalation, or dermal contact withon-site and off-site contaminants; 2) lead exposures to site workers during working hoursand the potential for exposures to family members due to lead transport on the worker'sclothes; 3) transport of contaminants from the facility to neighboring houses throughrunoff from the site resulting in dermal or inhalation exposures to the dusts carriedoff-site; 4) inhalation of particulates and gases from the incinerator and from smolderingdrums 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 tocontaminants through ingestion of contaminated garden produce. One resident also expressedconcern about the incidence of cancer.

While preparing this Petitioned Public Health Assessment (PPHA), ATSDR made thefollowing recommendations: 1) locate former site workers who were exposed to lead forfollow-up health activities; 2) evaluate the potential migration of soil-gas from thesite; 3) educate the community and health professionals about the contaminants of concernidentified at the site and potential health effects associated with exposures throughinhalation, dermal contact, and ingestion of the contaminated media; and, 4) ensure theprotection of people on and off the site during the remediation process.

Since the remediation process was completed in the spring of 1996, ATSDR requested thedata from the remedial actions. We will evaluate the data to ensure that the removal iscomplete and no contaminants remain on the site and provide appropriate recommendations.

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

ATSDR evaluated the contaminants in the subsequent sections of this document anddetermined whether exposures had public health significance. ATSDR selected and discussedthe contaminants based on the following factors:

  1. Concentrations of contaminants on and off the site.

  2. Field data quality, laboratory data quality, and sample design.

  3. Comparison of on-site and off-site concentrations with public health assessment comparison values for (1) non-carcinogenic and (2) carcinogenic endpoints.

  4. Community health concerns.

The presentation of a contaminant in the data tables in Appendix D indicates which contaminants were evaluatedfurther in this document, not that they resulted in adverse health effects from exposuresat the levels detected. These data are representative of the samples collected in thedifferent media prior to the completion of the removal actions at the site.

Comparison values for ATSDR public health assessments are contaminant concentrations inspecific media that are used to select contaminants for further evaluation. ATSDR andother agencies develop the values to provide guidelines for estimating the mediaconcentrations of a contaminant that are unlikely to cause adverse health effects, given astandard daily ingestion rate and standard body weight (see Appendix D for a description of the comparison valuesused in this public health assessment).

After the completion of the removal actions at the site, ATSDR evaluated the datacollected from the different media. The removal activities were completed in 1996 andthese actions eliminated the exposures to contaminants previously detected at the site.Currently, there are no known routes of human exposures and future exposures tocontaminated media were eliminated during the removal activities at the site. Therefore,no public health actions are recommended because no human exposures are occurring or arelikely to occur in the future. In the following subsections, ATSDR presents data analysisconducted 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 weresent to CDPHE/Organic Chemistry Laboratory on September 5, 1989 and analyzed forpesticides and volatile organic compounds (CDPHE, 1989). OnFebruary 8, 1990, CDPHE/Inorganic Chemistry Laboratory analyzed the samples for theirmetal content (CDPHE, 1990b). A blank sample was submittedwith the soil samples. Pesticide and total arochlor(1)levels were all below detection levels in the blank sample; pesticides below detectionlimits 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 describedabove 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. Thesamples were analyzed for total metals and volatile organic compounds (VOCs). In additionto these analyses, one of the samples was examined for pesticides and was found to bebelow the laboratory's analytical detection limit. On June 5, 1990, EPA's SpecialEnvironmental Analysis Section analyzed the samples for VOCs and pesticides (EPA, 1990). On August 20, 1990, CDPHE/Inorganic ChemistryLaboratory 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, aportable detector was used to screen for lead contamination in surface soil. Lead wasdetected 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 metalcontamination. However, due to the drum stacks, metal debris, and crushed car body partson the site, it was difficult to grid those areas and impossible to collect samples atthose locations (Ecology and Environment, 1991c). Soil coreswere collected for confirmation at 10% intervals. At the locations where contamination wasdetected, a 36 inch soil core was collected with a Shelby tube inserted by a Geoprobe. Thebottom of the soil core was taken as a grab sample for VOCs and the rest of the core wascomposited and analyzed for semi-volatile organic compounds, pesticides, PCBs, and metals(Ecology and Environment, 1991c). The data are summarized inTables 1, 2, and 3 in Appendix C.

From October 14 - 16, 1991, subsurface soil samples were collected with a backhoe atapproximate depths of 7 feet and 15-20 feet (Ecology andEnvironment, 1991b). After digging the trench, grab samples were taken from the middleof the backhoe bucket. During the sampling efforts 10 trenches were excavated and 20sample sets were collected. The grab samples were analyzed for volatile and semi-volatileorganic compounds, pesticides, PCBs, and metals. As part of this process, workers noteddebris present at the excavated depths, possibly indicating previous excavation at thesite. Exposure to on-site contaminants at the depths sampled (sampling depths ranged from3 to 20 feet) is considered improbable.

On-site Soil Gas

From July 16 - 18, 1991 organic soil gas samples were collected from the gridded areasusing an organic vapor analyzer (Ecology and Environment, 1991c).A geoprobe was used to install 2-foot deep soil gas screening holes to detect organic gascontamination and collect soil cores for confirmation samples. Confirmation samples werecollected at 10% intervals. Confirmation samples consisted of 36 inch soil cores collectedwith a shelby tube inserted by a geoprobe. The bottom of the soil core was composited andanalyzed for semi-volatile organic compounds, pesticides, PCBs, and metals. The samplingidentified organic vapor levels ranging from 0 to 100 ppm with an average of 5.5 ppm and amedian 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 Divisionanalyzed 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 theburner; the burner pit; an ash collection drum; a drain area; and, an oily sump (Ecology and Environment, 1991c). The results are summarized inTables 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 formedin the milling of uranium ores. During the August 21, 1987 sampling at the site, radiationlevels 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 siteperformed during June 5-7, 1984. The apparent source of the radiation were 12 drums foundon the premises (EPA/NEIC/DENVER, undated). The drums wereremoved from the site during the site remediation. In addition, thirty drums containingyellow-cake were stored in a semi-trailer located next to an occupied house (ATSDR, 1991a); these drums were also removed as part of theremediation process.

During the collection of an on-site ash sample, the radiation reading at the ash pilewas 10 times above background (Ecology and Environment, 1991c);however, EPA's on-site coordinator (EPA/OSC) noted that the instruments were not readcorrectly and subsequent field radiation readings showed that the initial measurementswere 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, sourcesof low level radiation, primarily in the form of beta and gamma emitters, were detected invarious drums containing an ash-like material. Low level radioactive drums were set asideand were disposed of as part of the uranium mill tailings cleanup efforts in GrandJunction (Ecology and Environment, 1993).

On-Site Ambient Air

From September 12 - 15, 1989, airborne contaminant data were collected from the parkinglot area and from approximately 100 meters downwind from the incinerator (UNC Geotech, 1990a). The samples were analyzed for volatileorganic compounds, semi-volatile organic compounds and endosulfan and endosulfan I. Duringthe 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 125locations throughout the Riverside community; 115 residents agreed to have their soilsampled and composite samples were collected from each home (Figure 7).The samples were analyzed for metals, polyaromatic hydrocarbons (PAHs), chlorinatedpesticides and polychlorinated biphenyls (PCBs). Thirty-three of the samples were alsoanalyzed for dioxins and furans and an additional 11 grab samples were collected fromareas near the site and analyzed for metals and PAHs (Ecology andEnvironment, 1992a). Sampling locations were determined on a property-by-propertybasis, 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 samplingprogram. Off-site lead contamination was further characterized because of concerns aboutexposures 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 propertiesand analyzed for metals including lead (Ecology and Environment,1992a). Off-site lead contamination was further characterized, because of concernswith exposure of area children to lead. The results of the lead analysis are summarized inTable 11 and 12, Appendix C.

Approximately 94% of the residential samples collected showed lead levels equal to orbelow 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 detectedat 21 ppm. In addition, lead was detected at 55.4 ppm in samples collected from the vacantlot on Crawford Avenue.

The mean concentration of lead in the western United States is 17 ppm with an observedrange of approximately 10 to 700 ppm (ATSDR, PHAGM, 1992). Inthe Riverside neighborhood, three values were noted above 700 ppm; with an averageconcentration of 158 ppm. However, due to the considerably uneven distribution (asymmetry)of the lead levels detected, the median(2) is a betterrepresentative of the levels detected. The median of the soil lead values from theRiverside community is 113.0 ppm.

Off-site Radioactive Material

As part of the September 24 - 26, 1991 residential soil sampling rounds, elevatedradiation readings were detected at three locations on West Main Street. The highestreading encountered was 0.15 mR/hr above background (Ecology andEnvironment, 1992a). An association of these readings with potential releases from theHansen 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 mainentrances to the Riverside neighborhood.

The Department of Energy (DOE) performed gamma radiation scans in the Riversideneighborhood and completed the remediation process for the properties that were eligibleunder the Uranium Mill Tailings Remedial Action (UMTRA) program. DOE sent certificationletters to the property owners indicating that their properties were remediated underUMTRA in accordance with EPA criteria.

C. Quality Assurance and Quality Control

In preparing this Public Health Assessment, ATSDR relies on the information provided inthe referenced documents. The Agency assumes that adequate quality assurance and qualitycontrol measures were followed with regard to chain-of-custody, laboratory procedures, anddata reporting. The validity of the analysis and conclusions drawn for this document isdetermined 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 onthe site, the staff encountered difficulty in gridding and were unable to obtain samplesin some locations. They also discovered a subsurface obstruction at location EP-9 duringthe screening and were unable to collect soil gas or surface soil samples from thislocation. Additionally, during the collection of the grab samples in the main building thestaff noted that the sample from the oily pit was two-phased and the laboratory could notanalyze the sample due to the fact that two-phased analyses were not covered under theircontract.

On May 2, 1990, three soil grab samples were collected. Analyses of the samples foundpesticides at levels below the laboratory's analytical detection limit. However, some ofthe analytical detection limits are above our comparison values; therefore, this pesticideanalysis is not adequate to enable us to evaluate the potential health impact fromexposures.

The data collected from May 24 to July 9, 1989 (Tables 1,2, and 3) representonly 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 concentrationsidentified were found in surface or subsurface soil. If the concentrations were confinedto the surface, the reported values would underestimate the concentrations actually foundin surface soil. In addition, if the contaminants were confined to subsurface soil, thepotential for exposures would be greatly reduced or eliminated (given the history ofpractices at the facility, this is a likely scenario).

From July 16-18, 1991, organic soil gas samples were collected from the gridded areasof the site. The sampling identified organic vapor levels ranging from 1 - 100 ppm with anaverage of 5.5 ppm and a median of 1.8 ppm; however, the organic gas or gases could not beidentified.

PATHWAYS ANALYSES

To determine whether nearby residents were exposed to contaminants migrating from thesite, ATSDR evaluated the environmental and human components that lead to human exposure.The pathways analysis consists of five elements: a source of contamination, transportthrough an environmental medium, a medium of exposure, a route of human exposure, and anexposed population.

ATSDR categorizes an exposure pathway as a completed or a potential exposure pathway ifthe exposure pathway cannot be eliminated. Completed pathways require all five elementsexist and indicate that exposure to the contaminant has occurred, is occurring, or mayoccur. Potential pathways are those in which one of the five elements is missing, butcould exist. Potential pathways indicate that exposure to a contaminant could haveoccurred, could be occurring, or could occur. An exposure pathway may be eliminated if atleast one of the five elements is missing and will never be present. The discussion thatfollows incorporates the pathways that were relevant to the site prior to the removalactions that were completed in 1996 (Table 13).Currently, there are no known routes of human exposures and future exposures tocontaminated media were eliminated during the removal activities at the site. Thetoxicological significance and public health implication of exposure to the contaminantconcentrations detected prior to the removal actions at the site are discussed in thePublic 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 tohave occurred at the site and the Riverside neighborhood. Exposures could have occurred toon-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-siteworkers 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 surfacesoil could have also been contaminated through surface water runoff from the site and/orthrough air/wind.

On-site: Surface soil samples collected in 1991 indicated the presenceof one pesticide, PCBs, and three metals. Children and adults who gained access to thesite for recreation were exposed to the on-site surface soil contaminants throughinhalation, dermal contact, or incidental ingestion. In addition, youths and adults whoworked 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 soilconcentrations exceeded 10,000 ppm and children were at greater risk of exposures to leadcontaminated soil through ingestion because of their frequent hand/mouth actions.

The Occupational Safety and Health Administration (OSHA) issued several citations thatindicated that site employees were exposed to lead at levels above the PermissibleExposure Limit (PEL) (OSHA, 1989). Workers were exposed tolead through inhalation, dermal contact, and ingestion during the bead blasting operationsand while cleaning their clothes with a vacuum that lacked a HEPA filter required to avoiddispersing lead dust into the air. In addition, the worker's change area (where theyvacuumed their clothes) doubled as a lunchroom. Employees entering the lunchroomfacilities 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 Hansenemployees fluctuated from approximately 9 to 15 at one time. According to the OSHA Denverofficial, five employees were involved in the OSHA citations against Hansen Containers. Itis not known whether these employees were residents of the Riverside community.

Off-site: Residential soil sampling revealed the presence ofpesticides, PCBs, semi-volatile organic compounds, PAHs, metals, and dioxins and furans.Children and adults may have been exposed through inhalation, dermal contact, orincidental ingestion of soil. The practices for vacuuming clothes and eating in the samearea at the facility resulted in direct and indirect exposures to site workers. It is alsopossible that these occupational exposures resulted in secondary exposures to other adultsand children in the community if the employee transported contaminants on their clothes totheir homes. In general, with the exception of metals, the off-site contaminants wereidentified 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 oron-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 haveresulted from the incineration process or from the wind carrying contaminants identifiedin soil. On-site air monitoring was limited to two days of sampling in 1989; collectedfrom the parking lot and from an area approximately 100 meters downwind from theincinerator. Sampling analyses identified the presence of ethylbenzene and xylene.

Additionally, gaseous and particulate airborne contaminants identified on-site may havemigrated off-site through the air pathway from the incineration process and this couldhave resulted in inhalation exposures. Exposures to gaseous and particulate airbornecontaminants 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 theRiverside community existed in the past; however, we cannot evaluate this possibility dueto the lack of data. Figure 5, Appendix A,shows the organic soil gas "hot spots" that were detected on-site in 1991. Thetwo 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 oforganic soil gas; however, the organic gas or gases could not be identified. Potentialexposures 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 beenexposed to on-site radiation. In addition, youths and adults who worked on-site may havealso been exposed to on-site radiation levels. The toxicological significance of exposureto the levels detected on-site will be discussed in the Public Health ImplicationsSection.

C. Eliminated Exposure Pathways

Waste Material

ATSDR believes that past exposures to waste material on-site were unlikely. Thesoil at the site was removed as part of the remedial process and the ash that wascontained in drums at the site prior to the remediation activities were removed as part ofthe removal actions; therefore, this pathway is eliminated.

On-site Subsurface Soil

Exposures to soil at the depths sampled are very improbable; therefore, this pathway iseliminated. The samples were collected with a backhoe at approximately 7 and 15-20 feetdepths, with actual sampling depths from 3 - 20 feet (Ecology andEnvironment, 1991b).

Groundwater

The Riverside Community is served by municipal water and there are no known privatedrinking water wells in the community; therefore, this pathway is eliminated.

PUBLIC HEALTH IMPLICATIONS

ATSDR classifies the Hansen Containers Site as a past Public Health Hazard because ofexposures to contaminants detected at the site. For people who live in the Riversidecommunity, 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) surfacesoil, and (3) breathing airborne on-site and off-site substances. The public healthimplications of these exposures are discussed in this section:

A. Toxicological Evaluation

The toxicological implications of contaminants of concern identified in theenvironmental contamination section of this document are evaluated by: (1) considering thetypes and concentrations of contaminants detected in the environmental media (air, waterand/or soil); (2) the routes (i.e., inhalation, ingestion, or dermal contact) by whichhumans 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 andthe severity of those effects are related to the amount (dose) of a contaminant that aperson may be exposed to on a daily basis and to the frequency and duration of theexposures.

Public health concern is greater for people exposed to contaminants at levels aboveestablished health guidelines for a critical length of time. Health-based guidelinesvalues are developed for contaminants commonly found at hazardous waste sites (see Appendix C). Examples of health guidelines are theATSDR's Minimal Risk Levels (MRLs) and the EPA's Reference Doses (RfDs). The MRLs and RfDsare estimates of daily dose of a contaminant below which is unlikely to produce adversehealth effects. MRLs are usually developed for ingestion and inhalation, and also foracute exposures (those less than or equal to 14 days), intermediate exposures (those of 15to 364 days), and chronic exposures (those of 365 days or more). ATSDR presents many ofthe health guidelines in Toxicological Profiles, that provide chemical-specificinformation on health effects, environmental transport, and human exposure to theparticular contaminant.

ATSDR also uses Environmental Media Evaluation Guides (EMEGs) and Cancer RiskEvaluation Guides (CREGs) as comparison values that correspond to a 1 X 10-6level of cancer risk. ATSDR's comparison values are media specific concentrations used byhealth assessors to select environmental contaminants for further evaluation; they are notused as predictors of adverse health effects or for setting cleanup levels. Mediaconcentrations below a comparison value are unlikely to pose a health threat; however, itdoes not necessarily follow that a media concentration above a comparison value representsa health threat. The potential for adverse health effects is related to the magnitude andduration 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'scrust. It has not characteristic taste or smell. Its most important use is in theproduction of some types of batteries, it is also used to make ammunition, some kinds ofmetal products (i.e. pipes, solder, sheet lead), and in ceramic glazes. Until 1991, leadwas 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 surfacesoil; most notably from homes with flaking lead-based paint and the use of leaded gasolinein vehicles (ATSDR, 1992f). Soil concentrations are typicallyexpressed in mg/kg, also known as parts per million (ppm). Soils next to houses withexterior lead-based paints may have lead levels as high as 10,000 ppm (ATSDR, 1990). The levels of lead in soil next to well traveledroadways may range from 30 to 2,000 ppm. The background levels of lead in soil in theEastern U.S. range from less than 10 ppm to 300 ppm and average 17 ppm; in the WesternU.S. they range from <10 ppm to 700 ppm and average 20 ppm (ATSDR,PHAGM, 1992).

Tables 11 and 12present the concentrations of lead detected in residential soil samples. The distributionand concentration of lead in off-site soils suggest that there is no widespread leadcontamination in the Riverside community and the Hansen site may not be the major sourceof the lead in the neighborhood soils. Almost 94% of all samples (120 of 128) containedless than 300 ppm lead, which places them within the range of most U.S. residential soils(Mielke, 1993). Five samples contained between 301 and 600ppm lead, which is still within the normal range for soils in the Western U.S. (from lessthan 10 to 700 ppm). Only 3 of the 128 soil samples were detected at concentration beyondthe normal range for this part of the country, and none of these samples were in areasfrequented by local children. Both the distribution and the relative scarcity of these"warm spots" greatly reduce the potential for high-level lead exposure in localchildren. (Note: A relatively high concentration may pose no more risk than a lowerconcentration if the potential for exposure is proportionately less). The soil lead levelswere low in the areas that local children most frequent, such as the Headstart Center andthe empty lot on Crawford Avenue. Therefore, the available soil data suggest that theconcentrations of lead detected in the residential soils do not pose a health hazard tosensitive members of the community.

No ATSDR Minimal Risk Level, EPA Reference Dose, or any other comparison value has beenestablished for lead; nor has any biological need for this metal been identified. Theprincipal route of exposure is food, but excess exposure and toxic effects are usually theresult of other, presumably preventable, environmental exposures (R.A.Goyer, 1991). Lead toxicity is usually the result of occupational exposure viainhalation for adults, and ingestion of contaminated soil, dust, or paint chips forchildren.

Public health efforts to minimize environmental exposures to lead are steadilyincreasing. The concerns with environmental exposures to lead stem from evidence thatchildren and developing fetuses are especially sensitive to lead (CDC,1991; ATSDR, 1992f; Rothenberget al., 1992). The results of some studies suggest that lead detected in the blood atlow levels (10 to 25 micrograms per deciliter or µg/dL) may be relatedto delayed mental development, reduced intelligence quotient (I.Q.) scores, poor attentionspan, speech and language handicaps, and impaired hearing (CDC,1991; ATSDR, 1992f); however, the evidence for such arelationship is mixed. Other studies suggest that, when all variables are properlycontrolled, there is no statistically significant association between blood lead levelsbelow 30 µg/dL and I.Q. deficits or academic performance (M.A. Smith et al., 1983; McMichael etal., 1988). In children, blood lead levels of 40 to 60 µg/dL are associatedwith peripheral neuropathy, while levels of 80 to 100 µg/dL may be associatedwith acute nephropathy, anemia, and overt encephalopathy (Goyer,R.A.1991). In adults, overt encephalopathy may also be seen, but at higher blood-leadlevels (100-120 µg/dL); at lower levels, hypertension (30 µg/dL) andchronic kidney damage (60 µg/dL) may occur. The health effect from lead toxicitywill depend upon the form of lead, the magnitude and duration of exposure, and thesensitivity of the individual. The greatest determinants of sensitivity to lead toxicityare age and sex.

Exposures to high levels of lead in soil can result in elevated concentrations of leadin the blood. However, blood lead levels will not correspond to soil lead unless: (1) thelead 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, themeasures of environmental contamination are not indicators of human exposure. In fact, itis possible for blood lead levels to be in the "normal" range in spite unusuallyhigh levels detected in soil if the contaminated soil is not consumed or ingested or thelead is not in a bioavailable form. Therefore, blood lead screening is the only indicatorof whether exposures are occurring at levels of health concern.

During September 23-27, 1991, ATSDR, in collaboration with the Mesa County HealthDepartment, EPA Region VIII, Grand Junction Fire Department, Concerned Citizens ResourceAssociation, and the petitioners conducted blood-lead screenings for the residents of theRiverside Community and other people living outside of the neighborhood who wereinterested in the screening. A total of 287 blood samples were collected and analyzed. Theresults support the conclusion that residents are not being exposed to lead at levels ofhealth concern. The correlation between the levels of lead detected in the blood of thechildren and residential soil is very poor. The actual blood lead levels in children weregenerally quite low. The majority of the young children (5 yrs old or younger) living inthis community had blood lead levels that were well below the national average of 16 µg/dL(NHANES II, 1984). Approximately 90% of the Riversidechildren tested had levels below 10 µg/dL, and none had blood levels exceeding17 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 agegroup had blood lead levels at or below 10 µg/dL, while approximately 35% hadblood leads exceeding 17 µg/dL. Fully half of the national sample had bloodleads in the range of 11-19 µg/dL, compared to less than 12% of the children inthe Riverside community. Thus, we do not believe that children in the Riverside Communitywere or will be adversely affected by existing soil lead levels.

Of the 41 young children for whom matching soil lead data are available, only threelived where the level of lead in soil exceeded 292 ppm. The blood lead levels of thesechildren (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 wereavailable for the highest blood lead value measured. All of the people living outsideRiverside who participated in the blood lead screening program had blood lead levels below10 µg/dL. Only eight of the out-of-town participants were 5-years old oryounger, 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, andzinc (Table 7, Appendix B).In general, the range of concentrations found in Riverside residential soil samples wastypical of normal soils in the Western U.S. (ATSDR, PHAGM, 1992).With the possible exception of arsenic, even the highest reported levels of these metalsis not expected to result in any adverse health effects in children or adults.

If young children (especially those exhibiting pica-soil behavior) regularly ingestsoil 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. ThisRfD corresponds to an estimated daily arsenic intake of 3 µg/day for a 10-kgchild and 21 µg/day for a 70-kg adult. The average daily intake in the U.S. wasestimated at 5 µg/day (HSDB).

Although the RfD is a dose level considered to be "safe", it does notnecessarily follow that any dose that exceeds the RfD is considered to be unsafe. The RfDis based on a lifetime (70 years) of exposure, contains built-in safety factors, and mustbe 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 5000mg/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 thewest 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, manypresumably "uncontaminated" soils in the U.S. would contain too much arsenic toqualify as "safe" for a pica child. Such apparent inconsistencies are notuncommon when a series of highly conservative assumptions are compounded in a singlenumerical estimate; therefore, the numbers must be interpreted in a practical contextbefore they are applied to real life situations.

In the case of arsenic a classical threshold of toxicity exists for non-carcinogenicand carcinogenic effects; therefore, these effects would be expected to occur only whenthe dose exceeds a given level. When considering these threshold effects, a daily arsenicintake 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 ofarsenic detected in residential soil would be only 40 µg/day (one tenth the safedose of 400 µg/day). However, the actual potential for exposure is much lessbecause 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 thatexceeded the normal range found in soils of the Western U.S. Over 96% (125 of 128) of allthe 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 soilsis comparable to that of other towns used as controls in arsenic contamination studies (NRC, 1991, pg. 211). Most importantly, the samples collected atthe Headstart Center and the empty lot on Crawford street (where children may be expectedto 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 polychlorinatedbiphenyls (PCBs), various pesticides, polyaromatic hydrocarbons (PAHs) and dioxins.Sampling analyses identified the presence of PAHs, pesticides, and dioxins at very lowlevels (Tables 8, 9,and 10). Human and animal studies indicate thatexposures to the contaminant concentrations detected in residential soils are severalorders 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 eliminatedthe potential for present and future exposures to the contaminants identified in on-sitesoil prior to the remediation. Due to the lack of data from the past, we cannot evaluatepast exposures to site-related contaminants and potential health effects. Theconcentrations of arsenic detected in on-site surface soil were within the normal rangefor 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; thisnumber 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 samplesat levels exceeding 10,000 ppm (Table 3, Appendix B). However, in the absence of data from the past, it isnot 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 leadscreening conducted in 1991 indicated that the levels of lead in children were within thenational norm; however, this information does not enable us to evaluate the likelihood orpossible extent of exposures in the past. The most important finding was that soil leadlevels were low in the areas that local children most frequent, such as the HeadstartCenter and the empty lot on Crawford Avenue. Therefore, the available data suggest thatthe concentrations of lead detected in residential soils do not pose a health hazard tothe community. Additionally, the remedial actions finalized on the site eliminated thepotential 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 nothreshold of effect). However, neither of these assumptions apply to these compounds atthe site because the site operated less than 40 years. Chlordane and PCBs inhibitintercellular communication in cell culture and enhance the production of hepatocellularcarcinomas in mice through an epigenetic mechanism that apparently involves promotingeffect on preexisting abnormal cells (Williams and Weisburger,1991). However, the mechanisms involved would imply a threshold of effect for bothchemicals.

High doses of PCB exposures may have immunosuppressive effects in humans and animals (Dean and Murray, 1991). A 15-yr study did not reveal excessmortality or cancer incidence in 142 Swedish capacitor manufacturing workers (Ellenhorn and Barcelloux, 1988b, p. 955). While the study may beconsidered too small to detect subtle changes in cancer rates, there is no othercompelling evidence that PCBs cause cancer in humans. Jaundice has been reported to occurin residents of homes recently treated with chlordane, but occupationally-exposed workersappear to be free of chlordane-related adverse health effects (Santolucitoand Nauman, 1992). In the opinion of ATSDR, the levels of chlordane and PCBs inon-site soils do not represent a health hazard to Riverside residents in the past. Theremedial 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 scanidentified releases of ethyl benzene and xylene. However, the facility ceased operationsin 1991, this prevented further exposures from the site operations. The toxicological datado not indicate adverse health effects associated with exposures to ethyl benzene andxylene. Analyses of the residential soil data did not identify elevated levels of organiccompounds (i.e. PCBs, PAHs, or pesticides); therefore, the airborne contaminants did notaccumulate to the extent that adverse health effects would have resulted.

Site workers may have been exposed through inhalation of lead and other chemicalsduring the bead blasting operation and while cleaning their clothes when the facility wasoperable (OSHA, 1989). However, no data are available fromthe past to better characterize this pathway; therefore, we cannot evaluate health effectsthat may have been associated with exposures.

As part of the September 1992 remedial actions, the EPA/OSC who was working at the sitenoted strong mercaptan odors. Similar odors were reported by Riverside residents. Themercaptan odors appear to be associated with the removal activities at the site. Methylmercaptan is a colorless gas with a smell similar to a rotten cabbage. It is a naturalsubstance present in human and animal tissues. It occurs in small quantities in a varietyof 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 presentin the natural gas from certain regions of the United States. Methyl mercaptan is alsomanufactured for use as a food additive, in pesticides, in jet fuel, in the plasticsindustry, and in making poultry feed (ATSDR, 1992h). Littleis known about what happens to methyl mercaptan after it is released to the environment orabout the potential health effects from exposures (specifically: human health effectsthrough inhalation). If gaseous methyl mercaptan is released on land, it adsorbs stronglyto the soil. In the atmosphere, methyl mercaptan will be oxidized by photochemicallygenerated 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 beenreported by workers exposed to mercaptans in general. Measurements in occupationalsettings such as wood-pulp mills have revealed methyl mercaptan levels below 4 ppm. Theonly human evidence of neurological and hematological effects of occupational exposure tomethyl mercaptans comes from a study of a 53 year-old black male who died after one weekof emptying methyl mercaptan tanks (exposure levels not known). The man was hospitalizedin a coma and died 28 days after admission. This study was based on an occupationalexposure 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 ofrats 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 atlevels 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 occasionallydetected at six on-site stations at levels ranging from 0.1 to 3.0 ppm with an average of0.4 ppm. It is, therefore, possible to say that the exposures of those people who actuallysmelled the mercaptans on other occasions may have been as high as 3.0 ppm. This is aconservative scenario for two reasons: 1) the maximum value, 3.0 ppm, was detected on-sitein a drum removal area, not in the residential area of the Riverside community. We have nodata on the methyl mercaptan levels in the residential areas; however, one would expectthe methyl mercaptan levels in the community to be much lower than 3.0 ppm; and, 2) whilethe average of the detections is 0.4 ppm, half of all detections are equal to 0.2 ppm orless.

Given the short duration and the expectedly low levels of methyl mercaptan exposures toRiverside residents, no adverse health effects are anticipated from the discussedexposures.

External exposure to radioactive material

Hansen Containers was permitted to store low-level radioactive waste. During theinitial stages of the remediation process, sources of low level radiation, primarily inthe form of beta and gamma emitters, were detected in various drums containing an ash-likematerial. Health concerns associated with exposure to those contaminants are related tothe risk of cancer (such as leukemia in children). Thirty drums containing yellow cakewere 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 havebeen exposed to on-site radiation. However, the radiation sources were confined to areasof 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 wereremoved as part of the remedial activities at the site and the potential for present andfuture exposures were eliminated.

As part of the 1991 off-site soil sampling, elevated radiation readings were noted atthree locations on West Main Street. The highest reading encountered was 0.15 mR/hr abovebackground (Ecology and Environment, 1992a), which would beof public health concern for exposure over the long term. An association of off-siteradiation levels with potential releases from the site are unlikely due to the distancefrom the facility. DOE remediated off-site areas under the Uranium Mill Tailings RemedialAction (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 agenciesand the community of concerns noted as part of the scoping visit for the site. The groundsfor 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 withlead-contaminated soils due to the fact that the site was unrestricted and the concernthat site-related contaminants may have migrated off-site; (3) the probability of adversehealth effects due to exposure to on-site lead; and, (4) that no actions (such asrestricting site access) were in progress to reduce or eliminate exposures to sitecontaminants (ATSDR, 1991f).

As a result of the recommendations made in the ATSDR Public Health Advisory, CDPHE, incooperation with ATSDR and the Mesa County Health Department (MCHD), conducted a communitycensus 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 toprovide information and personal contact was not achieved at seven homes; we distributedfact sheets providing information about the blood-lead screening program to theseresidences. Conversations with neighbors revealed that no children lived in thoseresidences. Based on the census information, we identified and scheduled for blood testing73 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 childrenin the area (Table 14, AppendixB). Of the blood samples taken, six children (11.3%) under 6 years of age and twochildren (2.3%) 6 to 18 years old had blood lead levels at or above 10 micrograms of lead perdeciliter of blood (µg/dL). The current Centers for Disease Control andPrevention (CDC) guidelines recommend that children with blood lead levels ranging from10-14 µg/dL be screened every 3-4 months until consecutive blood lead levels areacceptable (CDC, 1991). The results of this screening wereconsistent 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 leadsurveillance program and conducted follow-up actions of these individuals 11 and 14 monthsafter the initial testing and again in September 1994 - the results indicated that theblood lead levels were not a public health concern.

Lead deposited in dust and soil becomes a long-term source of lead exposure in childrenbecause it does not readily dissipate, biodegrade, or decay in the environment (ATSDR, 1988; ATSDR, 1992f). On theother hand, lead is cleared from blood to bone, other tissues, and urine in a fairly shortperiod of time. The half-life(3) of lead in human blood isabout 30 days. This means that a lead level detected in people's blood is an indicator ofrecent exposure. In other words, the blood lead screening conducted in 1991 does notreflect lead exposures that may have occurred several years before, as was the case forworkers on site.

Currently, there are no routes of exposure because the contaminants were eliminated aspart of the removal actions at the site. Therefore, no current or future exposures orhealth effects are anticipated.

State and Local Health Data

To address one community member's concern about cancer, ATSDR researched the availablearea data for cancer prevalence in the area. The data for Grand Junction are availabledown 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 codelevel. Therefore, we cannot evaluate data appropriate for the Riverside community.

We also contacted the local health departments for data pertaining to health outcomesrelated to the Hansen Containers facility. These agencies did not have site-specifichealth data to report.

C. Community Health Concerns Evaluation

The EPA conducted Community relations programs throughout the removal actions at theHansen Site. The removal actions were intended to stabilize or clean up the site. Thecommunity were informed of the removal actions as they occurred and the final CommunityRelations Plan was completed in May 1993. The document provided education to the communityabout the objectives and techniques used during the remaining investigation and clean upof the site. The EPA on scene coordinator also interacted individually with the localresidents and officials and distributed a fact sheet during the site clean up.

As part of the Public Health Assessment Process, ATSDR releases the health assessmentto the community for review and comments. This period also serves the community to provideadditional concerns related to the site. The PPHA was released for public comment inOctober 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 responseimmediately following the concern. However, these were concerns that were presented toATSDR prior to the completion of the removal actions. With the successful completion ofthe removal actions, we have not received or anticipate any community health concernsrelated to the site.

In the remainder of this section, ATSDR addressed the community concerns expressed aspart of the petition process (in bold) with a response immediately following the concern:

What are the health effects from dermal, ingestion, and inhalation exposure ofchildren to lead, pesticides, volatile organic compounds, and other on-site contaminants?

Adverse health effects associated with exposures to lead in children are not expectedbased on the available environmental data and the results of blood lead screening ofRiverside residents. However, it is not possible to rule out the possibility of adversehealth effects occurring for children who may have frequented the facility prior to itsclosure in 1991 and the site restriction. Any possible health effects depend on the degreeof individual exposures and those cannot be reliably estimated.

What are the health consequences of lead transport on worker's clothes from thefacility to their respective homes with the potential exposure to other family members?

Workers were exposed to lead dust during the bead blasting operations and probablytransported lead to their homes on their clothing. However, lack of data from the pastmakes it impossible for us to adequately evaluate this concern. Young children anddeveloping fetuses are especially sensitive to lead. The results of some studies suggestthat lead detected in the blood at low levels (10 - 25 micrograms per deciliteror µg/dL) may be related to delayed mental development, reduced intelligencequotient (I.Q.) scores, poor attention span, speech and language handicaps, and impairedhearing. 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 exposuresof workers to lead in the occupational setting of the facility? In addition, it has beenreported 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 onthe amount (dose), frequency, and duration of exposure of the particular substance. Thesedata are needed to evaluate potential health effects from exposures. Unfortunately, noexposure data from the past were available for ATSDR to review; therefore, we cannotevaluate past occupational exposures.

The following are general comments related to health effects associated with leadexposure: Acute toxicity is unusual, since lead is a relatively insoluble, cumulativesubstance. However, chronic exposure to high levels of lead may result in kidney damage,anemia, peripheral neuropathy, and encephalopathy. There is also evidence that exposuresto high levels of lead may reduce sperm count and increase the probability of spontaneousabortion. Increased blood pressure (hypertension) is the most sensitive adverse healtheffect in adults, especially in middle aged men. Fetuses and young children (6 years oldor 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 asresistant as adults.

What are the health consequences of the transport of contaminants from thefacility to neighboring houses through runoff water used to flush trucks and trailerson-site?

The soil sampling data collected from the neighborhood yards do not indicateaccumulation of rinse water contaminants. In addition, on-site soil samples collected froman 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 andgases from the incinerator operations; 2) dermal exposure to particulates (separateparticles) 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 ofairborne contaminants during the incineration process at the site; however, we cannotidentify the likely hazards associated with this concern because we do not know thechemical makeup of the emissions. Some community members reported episodes of nausea,headaches, general fatigue, nosebleeds, allergies, and burning eyes and nose. While theseconditions are biologically plausible responses of exposure to airborne contaminants, wecannot issue a statement about the extent/severity of actual or potential adverse healtheffects.

What health effects, if any, can be expected from exposures to contaminantsthrough ingestion of contaminated garden produce?

No adverse health effects are currently anticipated from eating garden vegetables grownin 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 theincineration process at the facility. However, there is no information available from thatperiod that would allow ATSDR tp evaluate exposure or the possibility of adverse healtheffects. Since the facility closed in 1991, contamination from site operations ceased.

A small number of residential soil samples contained slightly elevated levels ofmetals. Lead uptake from soil in plants is highly unlikely because it is typicallyimmobilized 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 somemetals may be considerable in lettuce, spinach, and other leafy vegetables, but has beenreported to be low in tomatoes.

Is there an association between the past episodes of nausea, headaches, generalfatigue, nosebleeds, allergies, burning eyes and nose among some Riverside residents andthe operation of the Hansen container facility?

The association is possible but it can not be determined with certainty because of thelack of data to indicate the amount of airborne contamination in the past. The healthconditions outlined above are biologically plausible responses of exposure to airbornecontaminants; however, they are also non-specific symptoms that could have a number ofother causes unrelated to Hansen Containers.

Is there a connection between the cancer cases in the Riverside community andthe operation of the Hansen container facility?

We cannot accurately evaluate this community health concern because: 1) the data forGrand Junction are available only at the ZIP code level and Riverside is a small componentof Grand Junction's ZIP code (81505); and, 2) the Colorado Central Cancer Registry doesnot report precise information down to that level. The available data indicate that theidentified site-related contaminants were not present at levels that would represent acancer hazard.

CONCLUSIONS

ATSDR classified the Hansen Containers site as a past public health hazard. Thisclassification was based on the fact that: in the past, children and adults hadunrestricted access to the lead contaminated soil on the Hansen site and former siteworkers were exposed to lead from the bead blasting operations at levels that exceededOSHA's permissible exposure limits. However, ATSDR was unable to evaluate past exposuresor adverse health effects in workers or Riverside residents which may have resulted duringthe operation of the facility because there were no data that adequately characterizedthose exposures. Currently, Hansen Containers is classified as a no public health hazardbecause: 1) facility operations ceased in 1991; 2) site access was restricted in January1992; and, 3) removal activities were completed in 1996.

Contaminants previously identified as being of concern included: lead, polychlorinatedbiphenyls (PCBs), aldrin, dieldrin, and various volatile and semi-organic compounds. Lead was considered the primary contaminant of concern from the Hansen Containersfacility due to the fact that the site was unrestricted and children and adults could havebeen exposed to lead at levels of health concern. ATSDR reviewed the data collected duringand after the removal activities. The removal activities eliminated the contaminants ofconcern; 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 toinform the community and local and federal agencies about conditions that may pose anurgent public health hazard. The health advisory focused on the fact that the site wasunrestricted, 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 andlocal agencies conducted blood lead screening for children and adults in the area. Thisinformation was needed to enable us to better characterize potential health effects fromlead exposures. The screening identified a small number of children under 6 years old withslightly elevated blood lead levels. CDPHE incorporated the people with slightly elevatedblood lead into a blood lead surveillance program. After follow-up of these individuals 11and 14 months after the initial testing and again in September 1994, the results indicatedthat the blood lead levels were not a public health concern. Additionally,off-site residential soil samples were collected and analyzed; the results indicated thatexposures to these soils did not present a public health hazard.

The community expressed concerns about health effects associated with exposures tosite-related contaminants. Specifically, they were concerned about: 1) health effects thatchildren and adults may experience from exposures through incidental ingestion,inhalation, or dermal contact with on-site and off-site contaminants; 2) lead exposures tosite workers and the potential for exposures to family members due to lead transport onthe worker's clothes; 3) transport of contaminants from the facility to neighboring housesthrough runoff from the site; 4) dermal and inhalation exposures to dust carried off-siteby surface runoff; 5) inhalation of particulates and gases from the incinerator and fromsmoldering 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) exposureto contaminants through ingestion of contaminated garden produce. In addition, oneresident 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 wouldadequately enable us to characterize potential past exposures. We evaluated the healtheffects from exposures to lead at the site and the Riverside community and conducted bloodlead screening for 287 individuals in 1991. The blood lead screening identified a smallnumber of people with slightly elevated blood lead levels. CDPHE, in cooperation withATSDR, conducted follow-up actions with the individuals with slightly elevated bloodlevels and the results indicated that no adverse health effects occurred. The siteremediation was completed; therefore, present and future exposures were eliminated.

Data inadequacies discovered during the preparation of this document include: 1) no airmonitoring data from the past are available to enable us to estimate exposures,specifically, during site operation of the incinerator; 2) the potential migration of soilgases from the site to residential areas was not been addressed; and 3) while organic soilgas sampling revealed on-site organic vapor levels ranging from 0 to 100 ppm, the identityof the organic gas or gases was not reported.

RECOMMENDATIONS

Cease or Reduce Exposure Recommendations

1. Review the remediation data to ensure that the site remedial actions were completedand the present and future exposures were eliminated or minimized.

PUBLIC HEALTH ACTIONS

Health Activities Recommendation Panel (HARP) Recommendations

In accordance with the Comprehensive Environmental Response Compensation, and LiabilityAct (CERCLA) of 1980, as amended, ATSDR evaluated the Hansen Containers Site, GrandJunction, Colorado, for appropriate health follow-up actions. The panel offered thefollowing recommendations:

HARP determined that the Riverside community residents needed assistance inunderstanding the pathways by which they have or may have been exposed, the potential forsuch exposures, and the potential adverse health effects of such exposures. Therefore,HARP recommended community and health professionals education. CDPHE under a cooperativeagreement with ATSDR, implemented the community and health professionals education in thisarea. ATSDR will evaluate additional remedial actions data for further public healthactions as needed.

Public Health Action Plan

Currently, there are no known routes of human exposures and future exposures tocontaminated media were eliminated during the removal activities a the site. Therefore, nopublic health actions are recommended because no human exposures are occurring or arelikely to occur in the future.

In order to respond to community concerns, and based on the HARP recommendations, thefollowing 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 Riversideresidential community. The program for the health care providers was designed to informthem of the current Centers for Disease Control and Prevention (CDC) guidelines, PreventingLead Poisoning in Young Children. CDC guidelines recommend that children withelevated blood lead values be screened every 3-4 months until consecutive blood leadlevels are acceptable. The program also provided advise to the public health professionalsand the local medical community of the nature and possible consequences of exposure tocontaminants at the Hansen Containers site. The value of obtaining a complete and accurateexposure history was emphasized. The community health education program providedinformation about the contaminants of concern at the site.



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