Determination if Site Specific Interior Dust Clean-up Levels are Protective of Public Health
HERCULANEUM LEAD SMELTER SITE
HERCULANEUM, JEFFERSON COUNTY, MISSOURI
The Missouri Department of Health and Senior Services (DHSS) and the Agency for ToxicSubstances and Disease Registry (ATSDR), were asked by the U.S. Environmental ProtectionAgency (EPA) to participate in a Herculaneum Lead Smelter Site workgroup. The workgroupconsisted of two consultants (Dr. Scott Clark, Ph.D., PE, CIH and Dr. David Sterling, Ph.D.,CIH), community members, representatives from the Missouri Department of Natural Resources(MDNR), ATSDR, DHSS and EPA. The workgroup was tasked with evaluating interior leaddust clean-up levels for Herculaneum. The workgroup submitted a final report, entitled the"Technical Report for Focus Group Recommendations, Herculaneum, MO" to the CommunityAction Group on October 6, 2003. Site-specific recommendations for establishing lead dustsampling protocols, setting clearance standards, determining if additional clean-up actions arenecessary and developing a model work plan were included in the report.
EPA asked that DHSS, in cooperation with ATSDR, review the submitted report to determine ifthe site-specific interior lead dust clean-up levels that have been recommended by the workgroup, are protective of public health. This Health Consultation will review therecommendations of their report and make a determination if the clean-up levels are protectiveof public health.
The Herculaneum lead smelter is an active facility that has been in operation in this communitysince 1892. The Doe Run Company currently owns and operates the smelter. The facility islocated at 881 Main Street in Herculaneum, Missouri, approximately 25 miles south of St. Louis,Missouri, on the Mississippi River. The smelter abuts residential neighborhoods on the north,west, and south, with the Mississippi River on the east. A lead ore concentrate, consisting ofapproximately 80% lead sulfide, is processed at the smelter. The ore is transported by truckfrom eight lead mines operated by the company near Viburnum, Missouri, approximately 75miles south-southwest of Herculaneum. The 52-acre Herculaneum facility consists of a smelterplant, 24-acre waste slag storage pile, and an onsite sulfuric acid plant (1).
The city of Herculaneum has an estimated population of 2,805 people, according to the 2000 USCensus. Several homes are within 200 feet of the smelter plant, and currently at least threehomes are within 200 feet of the slag pile, one of which is occupied. Figures 1 and 2 display thelocation of the smelter in relationship to the community (2). Three schools are in the city: a highschool, a middle school and a junior high school. The elementary school is approximately twomiles away in Pevely, MO. There are no licensed day-care facilities in the city of Herculaneum.
Environmental sampling has indicated that there is lead contamination throughout thecommunity. For example, lead has been found in yard soils at concentrations up to 33,100 partsper million (ppm) (3) and in ambient air ranging from non-detectable (ND) to 85 micrograms percubic meter (µg/m3) (4). Lead concentrations on streets have been as high as 300,000 ppm (5),with loading levels up to 8.72 milligrams per square foot or mg/ft2 (6). Although multiplesources of lead could be contributing to the overall contamination, an Exposure Investigation(EI) conducted by ATSDR in 2001 indicated that lead in paint and water at the two homesevaluated did not appear to be significant sources of lead exposure in the children who lived inthese homes and had elevated blood lead concentrations (7).
Efforts to address the overall lead contamination in the community have intensified sinceSeptember 2001, when the MDNR and the EPA confirmed that spillage of lead concentrate wasoccurring along transportation routes in the city (8). This information prompted DHSS to alertMDNR that the risks to the public surrounding the site were clear and present and that they werean imminent and substantial endangerment to the health of residents of Herculaneum (8). Subsequently, MDNR and EPA directed the Doe Run Company to expedite activities to clean-upexisting contamination and reduce/eliminate future contamination throughout Herculaneum. The Doe Run Company, with oversight from MDNR and EPA, has implemented severalexposure reduction activities since that time including addressing street lead contamination,controlling fugitive dust and smelter air emissions, soil removal/replacement and cleaning theinterior of homes with elevated lead dust levels (8).
Despite the actions taken to address existing lead contamination in Herculaneum, active sourcesof contamination remain. The smelter is currently operational, and is expected to remainoperational for the foreseeable future. Although many controls have been added to reducefugitive dusts and stack emissions from the smelter, the smelter is still permitted to emit up to858.8 pounds lbs of lead per day (9). Lead concentrate is trucked in for processing on a dailybasis. Improvements have been made in the hauling procedures; however, small concentratespills still occur, and concentrate is tracked out of the facility by the haul trucks. These factorstogether continually contribute to elevated soil lead levels. Elevated soil lead levels increase thelead loading levels at the exterior entry of homes, which in turn increases the interior lead dustlevels in Herculaneum. A speciation study of samples collected from Herculaneum streets, soiland houses concluded that 30% of household dust comes from exterior soil and 50% is fromroad dust (6).
Many of the homes in Herculaneum have lead dust levels that pose a potential health threat tothe residents living in them. As a result, in October of 2002, EPA asked Drs. Clark and Sterling,with input from the workgroup members, to evaluate current clean-up levels, establish lead dustsampling protocols, set acceptable clearance standards, determine if additional clean-up actionsare necessary and develop a model work plan.
In addition to recommending a lead dust clean-up level, the report discusses clean-up strategiesand monitoring plans to ensure that these actions will effectively reduce exposures to anacceptable level (6). For interior clean-ups, the report recommends following the protocol in theHUD Guidelines for the Evaluation and Control of Lead-Based Paint Hazards in Housing (10). The report recommends collecting interior samples before and after cleanup and on a quarterlybasis thereafter to verify the effectiveness of the clean-up. The need for soil removal andreplacement, long term interior and exterior monitoring, and continued health communicationand education were reiterated in the report. The report also suggests the formation of anOversight Board for continuing evaluation of the clean-up process and the establishment of a trust fund to help fund the clean-up of attics and walls as houses are renovated.
In considering an appropriate and protective dust lead clean-up level for this site, Drs. Clark andSterling and the EPA work group members reviewed the available Herculaneum environmentaldata and studies. They concluded that there was not enough existing data (blood lead screeningdata and the corresponding environmental data) to determine a dust lead clean-up level usingonly site-specific data (6). Thus, the available Herculaneum information was combined withstudies conducted at other lead sites to form the basis for the Herculaneum Interior DustTechnical Report and Work Plan. Data from sites other than Herculaneum were considered forthis report because they have similar contaminants and exposure pathways. The TechnicalReport is attached as appendix A and is referenced in this Health Consultation.
In developing a recommendation for a site-specific interior dust lead clean-up level forHerculaneum, scientific evidence was evaluated which indicates that the current EPA lead duststandard, 40 µg/ft2 for floors, may not be protective of public health at this site. The EPAstandard was designed primarily for houses where lead-based paint is the primary lead source(6). However, lead paint is not the only source of lead exposure in Herculaneum. For over 100years, the smelter has released lead in their stack emissions as well as in fugitive dust fromactivities throughout the smelter, which has built-up in soil and other media over time. Althoughlead emissions from the smelter are declining, the smelter is still allowed to release up to 858.8pounds of lead per day into the atmosphere (9). This continuing deposition and the historicalenvironmental burden that has accumulated must be taken into account in the development ofany interior lead dust clean-up level (6).
Additional evidence supporting the need for a site-specific interior lead dust clean-up level lowerthan 40 µg/ft2 can be found at the Big River Mining Site, a nearby lead mining area of Missouri(6). The Big River Mining Site is similar to Herculaneum in that elevated lead concentrationswere present in several site media and people were being exposed to that lead through severalexposure pathways. Because of the multiple exposure pathways present at the site, a site-specific floor clean-up level of 24 µg/ft2 was proposed and determined to be protective of publichealth at the Big River Mining Site (11).
Another factor that must be considered in determining clean-up levels for lead is the relativebioavailability. Relative bioavailability is a measure of how readily lead, or any other chemical,is taken up by the body. In general, the relative bioavailability of lead is approximately 30%. Astudy was conducted to determine the relative bioavailability of lead from Herculaneum. Thestudy concluded that the site-specific relative bioavailability of lead from Herculaneum wasapproximately 36%, which is higher than average (12).
Drs. Clarke and Sterling's review of these scientific studies and other lead site data analysis,were used as the scientific basis to propose an interior lead dust clean-up level of 20 µg/ft2 for Herculaneum residences (6).
Currently, one-half of the houses in Herculaneum that have had interior clean-ups completedhave average floor dust lead levels of less than 20 µg/ft2(6). With additional interior house dustlead removal, lead-based paint stabilization and ongoing street cleaning to remove lead, aninterior lead dust clean-up level of 20 µg/ft2 appears to be attainable (6).
Additional strategies to ensure that the actions taken at Herculaneum are effective and willeffectively reduce exposures to an acceptable level were discussed in the report (6). For interiorclean-ups, the report recommends following the protocol in the HUD Guidelines for theEvaluation and Control of Lead-Based Paint Hazards in Housing (10). These are standardprocedures used in interior lead abatements. The report recommends collecting interior samplesbefore and after cleanup to verify the effectiveness of the cleanup. Quarterly sampling of homeinteriors is recommended in the report to ensure that there is minimal recontamination occurringand to ensure the long-term effectiveness of the cleanup. The need for soil removal andreplacement, long term interior and exterior monitoring, and continued health communicationand education were reiterated in the report. These activities are ongoing, and are expected to continue.
Children and adults are exposed to lead in many of the same ways. However, children are notsmall adults. They differ in the behaviors that lead to their exposures as well as theirsusceptibility to toxic effects from lead exposures. Children are more likely to play outdoors andbring food into contaminated areas. They are also shorter than adults, so are more likely tobreathe dust and soil that are close to the ground. Children are smaller, resulting in higher dosesof chemical exposure per pound of body weight.
Further, children have rapidly developing body systems that can sustain permanent damage iftoxic exposures occur during critical growth stages. Compared to adults, children absorb moreof the lead they take into their bodies, retain more of the lead they take in, and are more sensitiveto its effects.
Children in this community are being exposed to lead inside their homes as well as outside intheir yards, playgrounds, parks, and while attending school. This community is faced withcontinuing widespread environmental contamination that is very different from othercommunities. Therefore, because children depend on adults for risk identification andmanagement decisions, it is prudent that further lead exposure be prevented by such efforts aslowering the interior lead dust clean-up level for this community and controlling other sources of lead in this community.
DHSS and ATSDR concur with the site-specific dust lead clean-up level (20 µg/ft2) in thecontext of related activities (use of the HUD Guidelines, pre- and post-cleanup sampling, long-term quarterly sampling, continued soil replacements, health communication and education)proposed in the "Technical Report for Focus Group Recommendations, Herculaneum, MO."
The lead smelter in Herculaneum has operated for over 100 years, and will continue to operateand be a source of lead in the community for the foreseeable future. Several environmentalmedia have elevated lead concentrations (soil, air, interior dust, road dust). Additionally, thelead present in Herculaneum has a relative bioavailability which is higher than average. Thesefactors combined indicate that a site-specific interior lead dust clearance level lower than 40µg/ft2 is appropriate to create a margin of safety for the residents of Herculaneum. Based on theavailable information about the site and the information reviewed in this report, an interior leaddust clearance level of 20 µg/ft2 offers that margin of safety.
The prudent public health actions outlined in the clean-up protocol and monitoringrecommendations in the report are the logical steps necessary to ensure continuation of a safer environment for the residents of Herculaneum, Missouri.
- EPA and MDNR should provide oversight to assure that procedures are implemented toattain and maintain the interior lead dust clearance levels in residences in Herculaneum asoutlined in the Herculaneum Technical Report and Work Plan. In particular, the regulatoryagencies should ensure that the HUD guidelines are followed for indoor clean-ups, that pre- andpost-clean-up and longer-term quarterly samples are collected and analyzed to ensureeffectiveness of the cleanup and that remedial efforts to decrease lead concentrations in other media should continue.
When additional information becomes available, DHSS will evaluate it thoroughly and, ifappropriate, update existing assessment documents. ATSDR and DHSS will respondappropriately to any request for additional information or action.
The Public Health Action Plan (PHAP) for the Herculaneum Lead Smelter site contains adescription of actions to be taken by the DHSS, ATSDR, and others. The purpose of the PHAPis to ensure that this health consultation not only identifies public health hazards, but alsoprovides an action plan to mitigate and prevent adverse human health effects resulting frompresent and/or future exposure to hazardous substances at or near the site. Implicit in this plan isa commitment from DHSS and/or ATSDR to follow-up on this plan to ensure that it isimplemented. The public health actions to be implemented by DHSS, ATSDR and /orcooperators are as follows:
- DHSS/ATSDR will continue to evaluate any additional data that become availableregarding human exposure or contaminants at the site, including identifying additionalexposure pathways and evaluating health impacts of risk reduction and remediationplans.
- DHSS/ATSDR developed and are implementing a comprehensive health education plan inthis community. Those efforts will continue and will focus on increased childhood leadtesting, awareness of lead poisoning, its adverse health effects, how to reduce exposures,especially for children, as well as residential interior lead dust clean-up and soilreplacement.
- DHSS and the Jefferson County Health Department (JCHD) should continue healtheducation activities for both the people in the community and area health care providers. These activities should focus on awareness of lead poisoning, its adverse health effects,how to reduce exposures, and encourage blood lead testing, especially for children.
- JCHD/DHSS/ATSDR will continue to assure case management of children with elevatedBLLs.
- DHSS/ATSDR are in the preliminary stages of initiating health study activities in thiscommunity.
Rachelle Kuster , Missouri Department of Health & Senior Services
Gale Carlson, Missouri Department of Health & Senior Services
Scott Clardy, Missouri Department of Health & Senior Services
Dennis Jordan-Izaguirre, Agency for Toxic Substances and Disease Registry
Cherri Baysinger, Missouri Department of Health and Senior Services
This health consultation for the Herculaneum Lead Smelter Site was prepared by the MissouriDepartment of Health and Senior Services under a cooperative agreement with the federalAgency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with theapproved methodology and procedures at the time the health consultation was initiated.
Technical Project Officer, SPS, SSAB, DAC
The Division of Health Assessment and Consultation (DHAC), ATSDR, has reviewed this health consultation and concurs with its findings.
Section Chief, SPS, DHAC, ATSDR
- Missouri Department of Natural Resources, Division of Environmental Quality,Hazardous Waste Program. Preliminary Assessment: Herculaneum Lead Smelter Site, JeffersonCounty, Missouri. March 30, 1999.
- Agency for Toxic Substances and Disease Registry. Health Consultation forHerculaneum Lead Smelter Site: Atlanta: US Department of Health and Human Services; 2001Jul 13.
- Environmental Protection Agency. Transmittal from Bruce Morrison to MissouriDepartment of Health and Senior Services, January 8, 2002.
- Missouri Department of Natural Resources. Transmittal from David Mosby to TonyPetruska, Environmental Protection Agency, Sample#A58, November 28, 2001.
- Walker P. Missouri Department of Health and Senior Services. Herculaneum, MissouriLead Contamination Health Threat. September 13, 2001.
- Clark, C. S. and Sterling, D. A. Technical Report for Focus Group Recommendations,Herculaneum, MO. October 6, 2003 Attached
- Agency for Toxic Substances and Disease Registry. Health Consultation on ExposureInvestigation on Herculaneum Lead Smelter Site, Herculaneum, Missouri. Atlanta: USDepartment of Health and Human Services; 2001 September 14.
- Agency for Toxic Substances and Disease Registry. Health Consultation onDetermination if Remedial Actions are Protective of Public Health, Herculaneum Lead Smelter Site, Herculaneum, Missouri. Atlanta: US Department of Health and Human Services, 2002 April 16.
- Missouri Department of Natural Resources. Restriction of Emissions of Lead from Primary Smelter-Refinery Installations. 10 CSR 10.6.120.
- Housing and Urban Development. Guidelines for the Evaluation and Control of Lead-based Paint Hazards in Housing. Washington, DC: U.S. Department of Housing and Urban Development, 1995.
- Sterling, D. A., Roegner, K. C., Lewis, R. D., Luke, D. A., Wilder, L. C. and Burchette, S. M. 1999. Evaluation of Four Sampling Methods for Determining Exposure of Children to Lead-Contaminated Household Dust, Environmental Research, 81(A): 130-141.
- Casteel, Stan W., Evans, Tim E., Bratton, William J. and Hammon, Tracy L. Bioavailability of Lead In Test Materials. Doe Run Experiment 1. Draft. June 2001.
October 6, 2003
C. Scott Clark, Ph.D., PE, CIH
University of Cincinnati
Department of Environmental Health
David A. Sterling, Ph.D., CIH
Saint Louis University
School of Public Health
St. Louis, MO
- Recommended Site-Specific Interior Cleanup Level
- Recommended Site-Specific Interior Cleanup Protocols
- Recommended Site-Specific Interior Sampling Protocol
- Other Action Items
- Other Action Recommendations
- A. Precleaning Monitoring
B. Post Cleaning Evaluation Of Interior Cleaning Performance
C. Follow-up Monitoring
- A. Additional Sampling (other than interior)
B. Long-Term Monitoring
C. Trust Fund
D. Health Communication
E. Task Force
- Focus Group Meeting 2 - November 20, 2002 - Annotated Selected References
- Focus Group Meeting 2 - November 20, 2002 - Comments/Insights On Site-Specific Data and Documents Distributed At October 23, 2002 Herculaneum Focus Meeting # 1
- Focus Group Meeting 2 - November 20, 2002 - Power Point Presentation Slides
- Focus Group Meeting 3 - December 19, 2002 - Recommendations For Herculaneum Draft Report
- Focus Group Meeting 3 - November 20, 2002 - Power Point Presentation Slides
- Focus Group Meeting 4 - May 29, 2003 - Response To Questions Posed By Focus Group Attendees Following December 19, 2003 Meeting
- Focus Group Meeting 5 - September 22, 2003 - Power Point Presentation Slides
- Summary Of Comments By Focus Group Members on Herculaneum Technical Report and Work Plan Submitted July 21, 2003
The Herculaneum Lead Smelter, located approximately 25 miles south of the St. Louis metropolitanarea in Herculaneum, Missouri, is an active lead smelter that began its operations in 1892. Manystudies have been conducted to help characterize the impact the smelter has had, or is currentlyhaving, on the surrounding community of Herculaneum, Missouri. Both past and present studieshave indicated lead levels that exceed the current cleanup level for soil. This soil cleanup level issometimes exceeded by more than 300 times. Current studies have shown that the road dust alonghaul routes contains extremely high concentrations of lead, which are of greatest concentration alongthe routes bringing lead ore to the smelter. These levels decrease in concentration as one movesaway from the smelter along the routes taken by the empty trucks. In some instances, the leadconcentration in road dust exceeded 190,000 milligrams per kilogram (mg/kg).
In addition to high levels of lead found in soil and road dust, several children have exhibitedelevated blood lead levels (EBL). To help reduce the children's risk of exposure to lead, the soilfrom several yards were excavated and replaced with soil with lead levels below 240 mg/kg(mg/kg = ppm). The first groups of yards excavated were those surrounding homes with childrenexhibiting EBL. Eventually, all homes with soil lead concentrations above 400 mg/kg will beexcavated.
For the surrounding community of Herculaneum, Missouri, cleanup or action levels were establishedfor air, soil, and interior floor dust wipe and interior windowsill dust wipe samples. No levels wereestablished for road dust or indoor carpet dust samples. The soil cleanup level of 400 mg/kg wasestablished using the EPA Region 9 Preliminary Remediation Goals. The air action level of 1.5micrograms per cubic meter (µg/m) was established using the National Ambient Air QualityStandards. The interior floor dust wipe cleanup level of 40 micrograms per square foot (µg/ft2)and interior windowsill dust wipe cleanup level of 250 µg/ft2 were established using standardsdeveloped by the Department of Housing and Urban Development (HUD). The HUD standards arebased on protocols established for lead-based paint cleanup. Because these levels do not account forlead arising from sources other than lead-based paint, such as lead smelter activities, Tetra TechSTART was tasked to coordinate the establishment of a proposed set of site-specific, scientifically-based interior lead dust cleanup levels. These proposed levels are to be developed by lead dustexperts, with input from a Focus Group which would consist of members of the community, several federal and state agencies, and the potential responsible party.
EPA will engage members of the community; lead dust experts; and representatives from theMissouri Department of Natural Resources (MDNR), Missouri Department of Health and SeniorServices, (MDHSS), Agency for Toxic Substances and Disease Registry (ATSDR), Jefferson
County Health Department, and the Doe Run Company to participate in the observation of thedevelopment of a site-specific, health-based, cleanup standard and action strategy for lead dustcontamination present in home interiors:
- Identify, provide and review critical and relevant studies on interior lead dust.
- Provide and review site-specific environmental data.
- Recommend site-specific health-based indoor dust cleanup level goals.
- Recommend site-specific sampling protocols.
In developing a recommendation for site-specific, scientifically-based dust lead clean-up levels for Herculaneum, one of the factors to consider is the considerable scientific evidence that the current US EPA standard of 40 µg/ft2 for floors is too high to ensure that less than 5% of the children have a blood level greater than 10 µg/dl (Lanphear et al, 1998). Additional evidence is from the Big River Site, a lead mining area of Missouri (Sterling et al, 1999). Another major consideration is that the EPA standard was designed to deal primarily with houses where lead-based paint (LBP) is the primary lead source. In Herculaneum, in addition to the lead-based paint that has been detected in some of the houses, there is also the additional source associated with the lead smelter activities. A portion of the exposure from smelter-related activities has been through the air for over 100 years. Fallout from these emissions has built-up in the soil and other deposition locations over time. Although lead from smelter emissions is apparently on the decline, Herculaneum has an historical environmental burden that has accumulated when the air lead levels and other emissions were considerably higher than at present.
An additional more recent lead source is spillage from ore concentrate that is now being trucked tothe smelter on haulage roads that pass through residential areas of Herculaneum. We feel this is amajor contribution to indoor dust based on: the lead speciation report by Johnson and Abraham(2002) indicating that the majority of house dust is derived from the soil and road; and thebioavailability report by Casteel et al. (2001) indicating that the ore concentrate was found to be anestimated 71% as bioavailable as the lead in lead acetate. In addition, the available dust lead datafrom the Herculaneum site exhibits a strong correlation of house dust lead with distance fromsmelter. House dust lead loading decreased as distance from smelter increased. For example, levelsat one-half mile were about one-half of those at one-quarter mile; levels at one mile were about one-eighth of those at one-quarter mile. However, exterior dust lead levels were not correlated withdistance from smelter, suggesting that they may be related to spillage from lead ore concentratetrucks that pass through the community.
The available blood lead data and corresponding environmental lead data for Herculaneum do not allow a determination with any certainty of the exact dust lead cleanup level to recommend using only site-specific data. An analysis of the limited amount of blood lead data available did reveal a very strong correlation with distance from the smelter as mentioned in the previous paragraph with house dust lead loading. This suggests house dust is one of the major contributors of lead exposure to children. Floor clean-up levels of less than 24 µg/ft2 determined from the Big River lead mining site (Sterling et al., 1999) in St. Francois, MO, were found to be associated with no more than 5% of the blood lead values above 10 µg/dl. Over 80% of the sites evaluated from the Big River study had soil levels greater than 400 ppm, the soil clean up level presently being used in Herculaneum, and the lead dust is primarily from ore concentrate, also similar to that used in Herculaneum.
Based on the above and similar findings by Lanphear et al. (1998) that the current EPA standard for floors of 40 µg/ft2 is not sufficiently protective, a floor lead clean-up goal that is lower than the current EPA standard for floors is recommended. From a scientific basis, and supported by Sterling et al. (1999), a goal of 20 µg/ft2 is recommended. Using the most recent data available, 12 of the 17 houses in Herculaneum have floor dust lead levels of less than 20 µg/ft2 measured during the last sampling period of each house. With additional interior house dust lead removal, lead-based paint stabilization and repeated exterior lead dust street cleaning, the latter on an expanded area basis, the goal of 20 µg/ft2 appears to be attainable. There is no corresponding literature available for windowsill clean-up goals; however similar reasoning would suggest a goal of 125 µg/ft2. Currently 50% of the houses have windowsill lead levels consistently less than this value at the time of the last sampling period. There is a statistically significant trend for house dust levels to decrease with time, which may be related to long-term impact of soil replacement, street cleaning and cleaning of additional homes.
For 15 of the 17 houses for which data has been presented, the special lead dust removal occurredprior to May 2002, the date that major emission control efforts at the Herculaneum smelter werein place. A communication provided to the Focus Group by Doe Run indicated that this prematurecleaning might be responsible for some houses not meeting the HUD cleanup goal. We suggest thatconsideration be given to cleaning these houses again.
For 4 of these 17 houses, at least one dust wipe sample during the last recontamination sampling forthat house had a lead level that exceeded either the EPA floor or window sill standard. Three of the 17houses in the last sampling period exceeded the EPA floor standard. Four houses exceeded thewindowsill standard, which included the same 3 houses above. Of the 3 exceeding the floor dustsample, 2 had interior lead-based paint present. These findings suggest that the soil removal andreplacement at the house and/or the household cleaning program were generally sufficient to bringdust lead levels below the present EPA health-based standard and to the proposed clean-up level.If houses that were cleaned before completion of the major smelter emission control improvementswere put into place are recleaned, as recommended in this report, levels are likely to further decrease. The excedences of current EPA dust lead limits may be due tohigh levels of lead dust found in street samples, deficiencies in the house cleaning protocol,contamination from neighboring house areas that have not received either soil abatement or houseclean up, contamination dust reservoirs in the house (e.g. attic spaces, basements and wall cavities),the presence of LBP, or continued contamination from the smelter operations or some combinationof these factors.
The results of the carpet cleaning efforts are similar to those reported in Ewers et al. (1994) and Yiin et al., (2002), where the difficulty in cleaning carpets was demonstrated. These data support the recommendation that consideration be given to replacing some of the carpets. Establishing objective criteria involving actual dust lead measurements of individual carpets would be difficult and expensive. It would involve determining the loading (µg/ft), cleaning the carpet, retesting and determining if the cleanup level was met. If not met, replacement would be warranted. It is likely that the cost of this procedure would be at least as high as the cost of replacement. Review of the literature doesn't provide any explicit information as to when a carpet should be replaced when routine or even extensive cleaning fails to adequately reduce lead loading. In the Ewers, et al. (1994) study naturally soiled carpet was taken from homes and vacuumed at a rate of 1 min/m2 using high efficiency vacuums. After four cleaning cycles of the carpets (total of 4 min/m2) the cumulative average amount of lead removed was 74% of total that was removed after a total of 10 min/m2. Ewers, et al. (1994) found that surface lead loading can actually increase after the first one or two vacuum cycles, however, on average lead loading will usually be reduced after the third cleaning. Lewis, et al. (2002) studied various aspects of lead loading, pile density, and wear on removal of lead-contaminated dust using a dry vacuuming process and typical home vacuum cleaners. Using artificially soiled carpets they found that lower initial lead leading did not affect of lead removal effect on removal from high or low-density carpet. At high loading, however, pile density had a major effect on lead removal with 54% more lead removal from low-density carpets. More importantly, at high levels of loading carpet wear has a significant effect on lead removal, particularly with low-density carpets (or possibly inexpensive carpets). In summary, it appears that many carpets may be able to be cleaned to reduce lead loading below HUD action levels. However it may take a number of thorough cleanings and the carpets may not remain clean if the carpet is heavily contaminated or worn. If carpet wipe dust lead levels do not meet the established goal after thorough cleaning, particularly if the carpet shows visible signs of wear, than it be removed from the house. It is recommended that, where feasible, new carpets not be put back into the housing, since it is easier to clean a solid hard surface more effectively than cleaning carpets. Some floors would have to be treated to fill cracks and other repairs made to make them cleanable and smooth enough for walking directly on them.
The carpets of many of the houses have been sampled using both the HUD wipe method and a HEPA sampling method on side-by-side areas. The HEPA method uses the same equipment as is used in the street and exterior entry dust sample collection. The vacuum method produces a sample that can be tested for both lead concentration (ppm) and lead loading (µg/ft2). Statistical analysis has shown that the concentration and loading are correlated (r-squared = 0.75, p <0.0001). The vacuum method sample has an average loading value about 150 times that of the wipe method since it is capable of capturing dust from below the carpet surface.
A brief examination of the X-Ray Fluorescence (XRF) paint lead monitoring results fromHerculaneum revealed that 8 of the 15 houses for which data were available showed lead-based paint(>= 1.0 mg of lead per square centimeter) on interior and/or exterior surfaces. For the houses whereexterior results were not provided, it was not noted whether or not exterior painted surfaces werepresent or tested. It is important that housing units be examined for lead-based paint using theprotocol specified in the HUD Guidelines when elevated blood lead children are present or wheredust lead level goals cannot be met. If the Jefferson County Health Department needs additionalresources to conduct such an expanded testing program, it would be helpful if such resources weremade available. Emergency paint lead stabilization and abatement funds/skills should be madeavailable such as for EBL events or other homes where young children move in and lead dust goal levels have not been achieved.
Ideally, cleaning should be performed in a manner so that residents can re-occupy the home the sameday. In order for this to be accomplished, the analytical method used to determine if the cleanup goalshad been met must be capable of providing results soon after dust wipes are collected, preferablywithin an hour. If floors have to be sealed, an overnight relocation will be required because thesealing material will take some time to dry. Residents should, if possible, not have more than one-overnight relocation. Doe Run and/or the cleanup contractor should be responsible for quicklyreplacing or fixing any items damaged by the cleanup with items of equal or greater replacementvalue. Prior to the initiation of any cleanup activity in a home the resident and the contracted cleanupteam should meet to review a standard cleanup contract outlining the process and specificresponsibilities of those involved. Consideration should be given to documenting pre-cleaningconditions through use of a video camera with the recording to be destroyed after satisfactorycompletion of the cleaning. Any special circumstances or issues associated with the residence and thescheduled cleanup will be noted and incorporated into the contract at that time. At a minimum,cleanup shall be performed following the protocol set forth in HUD Guidelines for the Evaluationand Control of Lead-Based Paint Hazards in Housing. Sampling of lead levels shall be performed inall locations specified in the protocol and any other areas determined to be needed such as because ofuse as a living area or otherwise affecting the living area. If a Herculaneum or house-specific interiorcleanup plan specifies more stringent or more extensive cleanup measures, the plan shall takeprecedence over the HUD Guidelines. A brochure should be developed, probably using an existingbrochure as a starting point, to assist the residents in performing some special lead dust clean-upoperations on their own. If overnight relocation is required, adequate provisions for relocation andlodging should be made.
The lead dust clean-up protocol in the HUD Guidelines for the Evaluation and Control of Lead Based Paint Hazards in Housing (HUD, 1995) should be specifically followed. These guidelinesspecify important details such as the amount of time needed for the cleaning process for bothcarpets (HUD Chapter 11) and hard surface areas. Cleanup shall also include furniture and playarea items. Cleaning should be performed in a manner so that residents can re-occupy the homethe same day whenever feasible. Performing a post clean-up test method that provides immediateresults is needed to facilitate this happening. Re-cleaning should occur in any room, and similarsurfaces in rooms not tested, that exceed the set value for the sampling method used.
Sampling for lead in house dust should be performed prior to all cleaning activities, and shouldoccur no more than seven days prior to cleaning. A modified HUD evaluation protocol should be usedwhich involves the collection of a minimum of seven to nine dust wipe samples taken from aminimum of 4 floors and 3 windows (Galke et al., 1999). Two children's bedrooms should be sampledif there is more than one child under the age of 6 living in the home. Recommended samplinglocations include: floor sampling from the interior entry, doorways to the kitchen, youngest child'splayroom area (may be living room) and bedroom, and second child's bedroom if present; interiorwindow sills from the child's bedrooms, playroom and kitchen. Additional floor samples must becollected in the attic and/or basement if used as a living or play area, or otherwise accessed frequently.
Portable x-ray fluorescence analyzers (NITON, Inc.) are capable of providing rapid analysis of dustwipes as soon as they are collected as has been documented by research of the authors of this report. Readings should be taken for 60 nominal seconds as specified by the manufacturer. Ifresults from floor dust wipe samples are at or above a value determined through site-specificdeveloped calibration curves, the level shall assume to be at or above the clean-up level establishedand cleaning shall be repeated. Evaluation of cleaning should be performed. All testing for lead inhouse dust following cleaning should occur no sooner than one-hour after, and no later than 24 hoursafter cleaning is complete. Subsequent testing of cleaning should consist of samples alternating fromone side to the other of the doorway or window for the first two times. If additional re-cleaning andtesting is needed, samples should be taken from alternate windowsill and floor areas.
If carpet lead dust wipe results are greater than set value, and the carpet is not consideredcleanable (i.e. would be damaged, etc.), then resident is eligible for carpet replacement, whichincludes removal of padding and cleaning of subfloor. Preferable to carpet replacement, asmentioned earlier, is ensuring that the uncarpeted floor is cleanable and otherwise appropriate forresidential use. Otherwise, decisions will be based on post cleaning results. Collection of a wipe froman immediately adjacent area from which a carpet vacuum sample had just been collected may provide useful additional information to be used in the decision-making concerning possiblecarpet replacement. If a carpet test following any cleaning, and particularly re-cleaning, exceedsset point, then resident should be considered for carpet replacement or making the floor cleanable.
An occupant satisfaction survey will be developed and used following the completion of allcleaning activities. The form should be designed to determine the resident satisfaction of theoverall process and allow feedback for modification of the process and procedures as needed.
All homes where cleaning is performed are to be checked on a quarterly basis if resources are available. Sampling will be performed in a similar manner and locations as the pre-cleaning monitoring. If one room exceeds the standard, a cleaning of that room must be offered. If two or more rooms exceed the standard, a cleaning of the entire house must be offered. If levels are found to be greater than or equal to 20 µg/ft2 for two follow-up tests, a more thorough inspection for lead re-contamination sources will be performed. This inspection should include lead-based paint; evidence of dust lead seepage from attics, air ducts and walls and outdoor sources. The results of this inspection will form the basis for the development of a site-specific intervention plan, and corrective measures taken. A complete inspection and determination of potential source such as above should also be performed for all elevated blood lead events. In addition, interim control measures shall be performed/provided, such as walk off doormats for entryways to reduce the tracking of dust, sod for bare yard areas, and so on.
Homes cleaned on one or more occasions prior to the adoption of the Revised Interior Cleanup Planshall be considered part of this plan, and are eligible for home quarterly follow-up based on the sameguidelines. These houses should be considered for additional cleaning if dust lead goals have not beenachieved. Issues associated with difficulty with obtaining initial and follow-up access into homesfor cleaning and monitoring need to be addressed.
Soil Replacement and Monitoring
A significant amount of interior dust comes from exterior sources. This connection has already beenrecognized in the Herculaneum cleanup project, insofar as residents are not eligible for interiorcleaning unless they first have their yard soil tested and replaced where necessary. Yardremediation should be done in the most effective manner possible with the least amount ofinconvenience to residents. Soil contamination poses two risks: residents can be exposed to leaddirectly from soil dust while they are outside their own and neighbors yards, and soil dust (containing lead) can contribute to household dust and hence to interior lead exposure. It is importantthat all residents eligible for soil testing and replacement participate in the program to help reducepotential for recontamination of neighboring areas.
The current US EPA standard of 400 ppm for bare soil in residential areas appears to be appropriatefor Herculaneum. Post intervention soil lead measurements in Herculaneum to check forrecontamination show an overall mean of 87 ppm. An ATSDR Health Consultation noted onehome in Herculaneum that had its soil replaced in 1999 with soil containing 14 ppm lead(ATSDR, 2002), had levels above 400 ppm in testing performed in 2001. This shows thatrecontamination has occurred. Since replacement soil containing only 14 ppm was apparently availablein 1999, we recommend that replacement soils have a lead level less than the current guideline of 100ppm, provided that the soil also meets agronomic requirements.
Using the soil preparation methods practiced at the time of this data collection the field portable XRF(X-ray fluorescence analyzer) device gave lead measurements that tended to underestimate the soillead concentrations. For example as demonstrated in Figure 1, using the pre-replacement availabledata the XRF must give a reading of 170 ppm or less for there to be a 95% certainty that the soil leadconcentration (as measured by atomic absorption (AA) analysis) is in fact less than 400 ppm (Clarkand Sterling, 2002). It may be useful to investigate other methods of preparing soil samples, suchas by a simple sieving process that can be performed in the field, so that the XRF results more closelymatch those obtained with atomic absorption. Another field portable lead-testing method that could be investigated for possible use is Anodic Stripping Voltammetry (ASV).
It is important to increase the participation of residents in the soil sampling and replacement program.Use of sod rather than grass seed could increase the percentage of residents who participate in theprogram. The yard remediation procedure should not take longer than one week; from the timeremoval of old soil begins until the time the sod has been completely installed. In addition this workshould be completed during the workweek (i.e. bare soil should not be left exposed over a weekend).There should be a minimum of six inches of topsoil; the soil should have a low lead content (less than100 ppm and as close as possible to the national average of 40 ppm). However, the replaced soil/sodmust meet the agronomic needs for which it is intended.
Based on a review of the results of the post-intervention soil monitoring protocol, there does notappear to be any evidence that the replaced soil is becoming contaminated during the first year sincesoil replacement. Since soil recontamination would be initiated with the top layers of soilbecoming contaminated from fallout or ground level transport of lead containing particles, the topone-inch soil lead sample would not readily reflect such contamination. Surface scraping samples area more sensitive indicator of contamination of the replaced soil by lead dust and were instituted by theEPA in Herculaneum during 2003. We did not have the opportunity to review the additional surfacesoil sampling data and so cannot comment on those results. If a written protocol is not yet prepared,a protocol for a soil-scraping sample is available in the Protocol from the Three City Urban Soil-Lead Abatement Demonstration Project (EPA 1993).
We suggest that quarterly monitoring include a collection of soil surface-scraping samples. B.
Long-term monitoring is important to evaluate the success of any intervention implementationprograms, to detect needed modifications/changes, and to help determine the need for continuingcorrective actions. This monitoring should be performed at homes that participate in the cleaningprogram and/or soil replacement program, at selected sentinel homes and at selected street samplelocations. Long-term sampling method types should include those for settled dust within homes (wipesand carpet vacuum samples), exterior and interior dust fall, soil scraping and cores, and street andexterior entry dust vacuums. Methods for all sample collections have been previously described hereand/or elsewhere.
Dustfall data would provide another way to monitor the impact of emission control measuresassociated with the smelter and its operations and the neighborhood dust lead removal efforts.Protocols for interior dust fall are available from the Trail, B.C. Task Force and from the US EPAUrban Soil Lead Demonstration Project (EPA/600/AP-93/0010, August 1993). Exterior dust fallmeasure should be obtained at areas that can be kept secured, such as air monitoring stations and/or bythe EPA trailer or school, and that are representative based on distance and typography. Weunderstand that EPA/Tetra Tech are considering and performing a dustfall trial. They shouldreference and/or discuss the dustfall method that they are developing.
We also recommend two exterior dust vacuum samples being added to the house testing protocol:an exterior entry sample and a street sample. These samples can be collected by the procedure that iscurrently being used in Herculaneum to collect street dust samples. At the time of the completion ofthis report, it is our understanding that this additional monitoring had already been added to theHerculaneum sampling protocol.
|Dust Vacuum - Carpet||Quarterly||Quarterly|
|Dust Vacuum - exterior entry||Quarterly||Quarterly||Quarterly|
|Dust Vacuum - street||Quarterly||Quarterly||Quarterly|
|Dust Fall - Interior||Quarterly||Quarterly|
|Dust Fall - Exterior||Quarterly - secure location|
|Soil Sera in -|
It is more cost effective to perform attic and wall cleanup at the same time as home renovations areunderway, or as additional lead-based paint hazard reduction measures are performed. Timing is theissue, and if these activities were going to occur after much of the other lead exposure reductionmeasures were to be implemented, then it would make sense to establish some procedure to make surefunds were still available to support these efforts. The time when ceilings and walls areremoved/replaced/repaired also presents good opportunity for considering whether additionalinsulation is needed for the home. The need for such insulation is independent from the lead issue, butit would be more economical to perform when access to wall space and attics is available. Other activities that might be included in such a fund are:
- Home renovations that will disturb areas not previously sampled and may be contaminated, such as air ducts, wall partitions, attics, ceilings, and basements;
- Further sampling and intervention needed when goals cannot be met - such as house dust levels after two follow-ups, recontamination of yards, and so on;
- Additional investigations and corrective action resulting from EBL events;
- Monitoring and cleaning needed when families are moving into previously untested homes with children;
- Long term relocation during home remediation; and,
- Permanent relocation, such as home buy out. A mechanism/plan is needed to eventually bring these into lead safe housing condition for re-occupancy or to be replaced by new housing.
Implementation of an effective workplan requires that Herculaneum residents believe that the plan iseffective, they must trust the individuals that will be implementing the plan, and they mustparticipate in the plan. Such trust cannot be expected unless the residents are provided sufficientinformation about, and input into, the process. This can be best achieved through some or all of thefollowing educational/communication methods.
Community-specific literature is needed. This information is also needed for painters, remodelers,hardware stores in addition to homeowners and renters. It would also be useful to develop or locateexisting education modules that can be used in the public schools at various grades. If there is avocational school in the area that has home improvement courses, they might be able to disseminate the educational materials.
Educational materials should be prepared for such activities as renovations, attic access and wallinterior remediation. The results of the exploration of Doe Run test and other homes could providesite-specific intervention techniques and photos of situations that occur in Herculaneum.
It is necessary to provide for the disclosure to present and future home occupants and owners onexisting and potential lead hazards. This is important and is required by law when there is informationon lead hazards. This information disclosure also should include real estate agents, financialinstitutions, etc.
The broad representation of the Task Force can help develop appropriate delivery modes foreducational materials. It would be useful to invite others to observe some of the Task Force and otherrelated meeting and/or to hold the Task Force meetings in conjunction with PTO's, and so on. Theremay be a teacher(s) in the school system that is interested in using some aspect of the Task Forceactivities as a class project or for extra credit. The State of California produced a `lead calendar' a coupleof years ago which used drawings by school kids to illustrate a number of points- the effects of lead onchildren, ways lead exposure occurred, ways to reduce lead exposure, etc. There are a number of suchexamples. Maybe some can be developed here.
A focus group could also explore reasons why soil replacement and special home treatment for leadremoval programs do not seem to be acceptable to a number of community members.
All Herculaneum work plan activities shall have an ongoing evaluation such as by a Community Oversight Board.
Such a board could consist of members from the following groups:
- The Herculaneum Community Advisory Group
- US EPA
- Other agencies (DNR, ATSDR, etc.)
- Doe Run Corporation
- Outside experts
The Board could review comments or complaints made by residents. The Board could reportgrievances and recommend courses of action to remedy such grievances to the responsibleparties.
To aid the Board, residents should be given evaluation forms to complete upon conclusion of anyworkplan activities. These evaluation forms should be simple to complete and submit to the Board.
On an annual basis all workplan activities shall be evaluated in order to:
- Assess the effectiveness of the plan. Measures of effectiveness include communityparticipation rates, level of community satisfaction with the decontamination program,efficiency of the protocol, and attainment of lead contamination goals.
- Recommend and implement changes to the plan, if deemed necessary to increase the effectiveness of the cleanup process. The cleanup plan shall maintain its basic structure and function in any revisions, but specifics such as cleanup procedure, lead clearance goal levels, or grievance reporting mechanisms may be modified to better achieve Herculaneum health goals.
Since lead in dust is mobile, it can move from site to site within a community. Such movement varieswith time and varies between communities depending on the sources and activities occurring.Street dust lead has been found to contribute to the loading at the exterior entry to housing, which thenimpacts interior dust lead levels. In Herculaneum, spillage of lead concentrate from haulage activitiescan contribute to high street dust lead levels in some areas. In areas where paint lead is the majorsource, soil and exterior entry dust lead has been contributing to soil lead. Lead levels in variousenvironmental compartments (street dust, other exterior dust, soil and interior dust) are interrelated.Since the sources of the lead can vary, the pathways among the environmental lead variables canalso vary. In the HUD Evaluation (Clark et al., 2003), which involved houses in many areas of thecountry, it was found that in general lead from housing (exterior dust and soil) affected lead levels onstreets. (In Herculaneum the reverse may be true, especially along the haulage routes.) In addition, theHUD evaluation results showed that lead at the exterior entry of the house moved toward the interiorportions of the house. A study of samples in Herculaneum from streets, soil and houses concludedthat 30% of household dust comes from exterior soil and 50% is from road dust (Johnson andAbraham, 2002). Similar conclusions about the contribution of soil to interior dust were reachedin several other studies conducted outside of Herculaneum: One study estimated that 30% ofhousehold dust carne from soil (Calabrese and Stanek, 1992). Another study found that 37% ofhousehold dust came from soil (Sterling et al, 1998). Yet another study estimated that 50% ofhousehold dust originated in soil (Forbes et al, 1986). Monitoring all three locations can help insubsequent corrective actions for homes where re-contamination continues to be a problem.
Dust lead levels on Herculaneum streets are the highest reported (Clark and Sterling 2002),probably due in part to the transport of lead concentrate through the streets in Herculaneum. Areview of the street cleaning data presented at the September 2002 Focus Group Meeting revealed a considerable overlap in lead dust concentration and loading between primary andsecondary lead concentrate haul routes Overall, concentrations and loadings appear to be loweron the secondary haul routes than along primary haul routes. There is, however, a considerableoverlap in the ranges of values with maximum values at sampling locations varying from 5900 to190,000 ppm (mg/Kg) compared to 37,000 to 94,000 for the primary routes. Values at secondaryroute sampling stations ranged from 1,009 to 34,900 ppm (median 3,700) and 0.72 to 7.22-mg/ft2 (median 1.34), compared to 8,100 to 40,000 ppm (median 16,000) and 0.77 to 8.72 mg/ft2(median 2.38) for the primary route stations. The overlap raises the question of whether otherstreets in Herculaneum have similarly high levels. Concentrations of lead in street dust inHerculaneum (median of 16,000 ppm and 3,700 ppm on primary and secondary routes,respectively) are much higher than those in Trail where levels were 1123 ppm before the newsmelter was built and 888 ppm afterwards. The street dust lead loadings in Trail decreased from20 mg/ft2 before the smelter was installed to 11 mg/ ft2 afterwards. The Trail levels are muchhigher than those in Herculaneum, median of 2.38 mg/ft2 and 1.34 mg/ ft2 on primary andsecondary routes, respectively.
To evaluate the relationship between exterior entry dust lead and lead levels in street and housedust, we recommend that the sampling method presently used in Herculaneum to obtain streetsamples should be employed at all homes being monitored to sample their exterior entry areas andadjacent street dust. Additionally, street dust monitoring locations should be established near thesmelter - especially near entries and exits to property (haulage roads, employee and supplier entryroads etc) to help monitor the effectiveness of smelter emissions and haulage spillage reductionactivities. Sampling sites on streets that are not primary or secondary haulage routes should also beselected.
The frequency of the monitoring for street dust should be quarter, but with the additionalsampling specified here and in later sections following. Depending on the results of this expandedstreet dust sampling, the need for cleaning these other areas can be assessed. If levels are similar toprimary or secondary haulage routes, cleaning should be considered on a similar frequency.
Houses of representative ages and locations in regards to distance from the smelter and ore haulageroutes should be included. It is possible that this has already occurred. It should be possible to finddata on the age of the Herculaneum housing stock to make sure that the houses sampled arerepresentative of the housing in the community.
Attics are usually very dusty. Since attics are usually designed to have ventilation that is adequateto prevent moisture build-up, there are openings to the outside air. These openings have allowed air contaminants to enter the house over the years and the particles to settle. Sealing the attics wouldhave to be performed in a manner that would preserve the ventilation characteristics while at the sametime trying to minimize entry into the living space. Provided the ceilings are intact, most of the atticcontaminating that enters the living space probably comes through the access to the attic (trap doors,pull-down stairs, regular stairs etc). It would first have to be determined the type of access to theattics and the use of the attics. This can range from very limited through a trap door of some type tofully finished attics. It is likely that many of the homes have the former type. If that were the case itprobably would be more effective to prepare a better trap door, taking care to prevent housecontamination during the process. If the ceilings below the attics are in poor condition and containlead-based paint, then replacement may be warranted since patching plaster is expensive. To obtain a smooth finish, moreover, it is usually more economical to replace the plaster ceiling withdrywall. If that were done, it would make sense to clean the attic at the same time since the dustwould be disturbed in the process. The basic cleanup effort needed for this task, would amount to amajor portion of the attic clean up.
In order to explore the level of lead contamination in attics and within wall, and the impact ofattic fan use, it would be useful to explore contamination levels and useful remediation techniques insome vacant houses that have been purchased by Herculaneum. Various approaches could be takento clean attics, ductwork and walls; the extent of lead contamination in these areas could bedetermined and the extent to which these locations of lead dust contaminate the living spacecould be explored. As long as attics are not part of the living space, site-specific clean-up levelswould not need to be achieved, only a significant reduction in available lead dust and a reduction of its impact on living areas.
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