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HEALTH CONSULTATION

BUNKER HILL MINING AND METALLURGICAL
KELLOGG, SHOSHONE COUNTY, IDAHO


DISCUSSION

In this health consultation, ATSDR will review available sampling data for surface soil,household dust, and blood lead to determine if the above site-wide objectives are being met andto determine if the lead is present in these media at levels of public health concern. ATSDR willalso review available air sampling data to evaluated whether the levels of particulates and lead infugitive dust are a public health concern. In order to evaluate the effectiveness of the soilremediation barriers, ATSDR's evaluation will focus on sampling data for the city ofSmelterville because Smelterville is the only site community in which remediation of residentialyards, commercial properties, and ROWs has been completed. In addition, ATSDR will limit itsreview to data collected in Smelterville from 1997 to present because soil remediation activitiesin Smelterville were not completed until 1997. Sampling data for heavy metals other than leadwill not be reviewed or evaluated in this health consultation.

Surface Soil

Lead levels in soil samples from residential yards in Smelterville for the last 3 years are shown inTable 1. Soil samples were collected in two different ways: (1) from yards of homes withchildren who participate in the annual blood lead screening program, and (2) from yards of allcooperating homes in the community (not just those with children). As shown in Table 3, overthe last 3 years, lead levels in both sampling categories met the site RAO goals for residentialsoil of 350 mg/kg as a community wide geometric mean and 1000 mg/kg for any individual yard. In addition, the geometric mean soil concentrations are below the EPA national soil screeninglevel of 400 mg/kg.

Table 1.

Lead Levels in Smelterville Residential Yards
YearSoil Concentration(mg/kg) - Yards withChildren1Soil Concentration(mg/kg) - All Yards2Site Soil Cleanup Goal(RAO) (mg/kg) EPA LeadScreeningLevel(mg/kg)
GeometricMeanMaximumGeometricMeanMaximumGeometricMeanMaximum
1999179627122NR3501000400
1998133616126NR3501000400
1997147766126NR3501000400
1sampling data from yards of homes occupied by children participating in the annual blood lead survey only.
2includes sampling data from yards of homes throughout Smelterville, not just those with children.
NR- not reported or not available

Household Dust

Lead levels in household dust inside Smelterville homes were measured in 1997, 1998, and 1999by both vacuum bag sampling and by dust map sampling. Separate lead dust studies wereconducted by the Idaho Panhandle Health District (PHD) and by TerraGraphics EnvironmentalEngineering, Inc. (TerraGraphics). The PHD studies were generally limited to those homeswhere children resided and had participated in previous blood lead screenings while theTerraGraphics studies included homes with and without children.

As shown in Tables 2a and 2b, the lead levels were generally higher in samples from the dustmats than in samples from the vacuum bags. By 1999, geometric mean dust levels, as measuredby vacuum bag sampling, were below the 500 mg/kg RAO in homes with children and slightlyabove the RAO in homes community-wide. In addition, dust levels in vacuum bags from someindividual homes continued to exceed the maximum RAO of 1000 mg/kg. Dust mat samplesfrom homes with children and from homes community-wide exceeded both the geometric meanRAO and the maximum individual house RAO throughout the last 3 years.

Ingestion of housedust lead has been identified as a major route of lead exposure (especially foryounger children) at the site. According to EPA reports, reducing geometric mean housedust leadconcentrations to 500 mg/kg (the dust lead RAO) or less is required to achieve the site-wide childblood lead RAOs. Even then, some individual children, especially those living in homes withunremediated yards and with housedust levels at or near the maximum ROA (1000 mg/kg), may have a greater than 5% chance of exceeding the blood lead levels of concern (10 ug/dL).

Table 2a.

Smelterville Indoor Dust Lead Levels - Homes with Children1
YearVacuum BagsDust Mats Site Cleanup Goals(RAOs) for Dust Lead (mg/kg)
NumberofSamplesDust Lead Concentration(mg/kg) NumberofSamplesDust Lead Concentration(mg/k)
GeometricMeanMaximumGeometricMeanMaximumGeometricMeanMaximum
1999154592150NRNRNR5001000
19982057011002971526805001000
199762729401365018805001000
bold - concentration exceeds site cleanup goal
1samples collected only at homes with children who participated in blood lead screening program

Table 2b.

Smelterville Indoor Dust Lead Levels - All Homes1
YearVacuum BagsDust Mats Site Cleanup Goals(RAOs) for Dust Lead (mg/kg)
NumberofSamplesDust Lead Concentration(mg/kg)NumberofSamplesDust Lead Concentration(mg/k)
GeometricMeanMaximumGeometricMeanMaximumGeometricMeanMaximum
1999105962000NR568>10005001000
19981543915907792526605001000
1997115751957018180848005001000
bold - concentration exceeds site cleanup goal
1samples collected at homes throughout the community (with or without children)

Blood Lead

Blood lead levels in area children age 9 months to 9 years have been monitored yearly by thePHD since 1988. The most recent blood lead levels for children in Smelterville are shown inTable 3. Blood lead levels in Smelterville children have generally been declining over the pastseveral years as more residential yards, commercial properties, and ROWs are remediated. In1999, the blood lead RAO that requires less than 5% of children to be above 10 ug/dL wasachieved. However, the blood lead RAO that specifies that no child be above 15 ug/dL was not.

Site-wide, one and two year old children generally have the highest average blood lead levels andthe highest incidences of elevated blood lead levels (>10 ug/dL) among all age groups. As such,it is possible that including blood lead data for older children (e.g. 9 year olds) may "dilute" thehigher levels found in younger children. Therefore, the broad age range (9 months-9 years) usedto report blood lead levels may underestimate the site's public health risks for younger children.

Table 3.

Blood lead levels in Smelterville children (age 9 months - 9 years)
YearLead Blood LevelSite Cleanup GoalsCDC Levelof Concernin Children(ug/dL)
Arithmetic Avg.Concentration.(ug/dL)PercentageChildren>10 ug/dLPercentageChildren>15 ug/dLPercentage
Children
> 10 ug/dL
PercentageChildren
> 15 ug/dL
19994.342<5010
19986.4142.3<5010
19975.690<5010
bold - exceeds site cleanup goal; NR - not reported or not available

Ambient Air (Fugitive Dust)

Lead and Total Suspended Particulate (TSP) levels in ambient air have been monitored inKellogg (at the Kellogg Medical Clinic) for many years. Monitoring data from the last 9 years(1990-1998) are shown in Table 4. Lead air levels at the Kellogg station have not exceeded theNational Ambient Air Quality Standard (NAAQS) of 1.5 ug/m3 (quarterly average) since thesmelter shut down in 1981. In addition, long-term (i.e., yearly) TSP levels have not exceeded theNAAQS for particulate matter less than 10 microns (PM10) of 50 ug/m3 (annual average) since1992. In contrast, short-term (i.e, daily) TSP levels have exceeded the NAAQS of 150 ug/m3(24hr average) periodically since 1990. However, no exceedences have occurred in the last fewyears (since 1995).

Ambient air monitoring at sampling stations in other site communities, including Smelterville,was discontinued in 1988. Therefore, no sampling data are available to evaluate ambient levelsof lead or particulates in these communities since remediation of residential yards began in 1989.

Table 4.

Ambient Air Lead and TSP Levels at Kellogg Medical Clinic Station
YearLead (ug/m3)TSP (ug/m3)
MaximumQuarterlyAverage
Concentration
NAAQS(QuarterlyAverage)AnnualAverageConcentrationNAAQSfor PM10
(AnnualAverage)
Maximum
24-hr AverageConcentration
NAAQSfor PM10(24-hrAverage)
19980.151.54750114150
19970.071.5NR50NR150
19960.101.541.450103150
19950.181.546.550210150
19940.101.548.150158150
19930.081.544.050182150
19920.071.557.550355150
19910.111.549.550180150
19900.151.549.450 151150
bold - exceeds applicable NAAQS

Localized air monitoring to evaluate fugitive dust levels during remediation activities conductedby the U.S. Army Corps of Engineers (ACOE) and the Upstream Mining Group (UMG). From1995 to 1999, the ACOE collected approximately 800 samples for TSP around 7 cleanup areas;most of these samples were also analyzed for lead. The data from these samples indicate that theTSP levels exceeded the 24-hour NAAQS standard (150 ug/m3 PM10) 47 times. The majority(39 out of 47) of the exceedences reportedly occurred in 1997 and 1998 around heavy haul-routeareas such as the "Multiplate" (overpass) structure in Smelterville. During the 5 year monitoringperiod, the annual average lead concentrations, which ranged from 0.150 ug/m3 to 0.355 ug/m3, never exceeded the NAAQS (1.5 ug/m3).

The UMG has monitored TSP and lead air concentrations during their yard remediation activitiessince 1994. TSP levels were measured weekly in real time (instantaneously) around the soilcleanup areas, and lead levels were measured daily in the personal breathing zone of remediationworkers. From 1994 to 1999, out of more than 2300 monitoring records, no exceedences of theOccupational Safety and Health Administration (OSHA) standard for TSP (15 mg/m3) wererecorded, while the OSHA permissible exposure level (PEL ) for lead (50 ug/m3) was exceeded 3 times and the OSHA action level (30 ug/m3) was exceeded once in the workers' personalbreathing zone.



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