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Pre-grading Phase 2



The Nine Mile Run slag site is a 240-acre former slag dumping site that the city of Pittsburgh,Pennsylvania is developing for residential housing units in a three-phased construction project. The United States Environmental Protection Agency (EPA) and concerned local citizensprovided the initial requests in the late 1990s for the Agency for Toxic Substances and DiseaseRegistry (ATSDR) and the Pennsylvania Department of Health (PADOH) to evaluate healthhazards associated with development on the site. PADOH and ATSDR prepared six healthconsultations (HC) evaluating various aspects of the site including adequacy of environmentaldata, physical hazards, and air quality. PADOH and ATSDR concluded in HC No. 4 thatuncontrolled dust from grading could pose a chronic airborne-manganese inhalation exposure problem and recommended dust control measures and air quality monitoring during Phase 1grading. Both dust suppression and air quality monitoring were conducted prior to and duringPhase 1 grading. This HC evaluates the air quality data collected before and during Phase 1grading, and the pre-grading Phase 2 slag data, to determine if future grading/construction willcreate a potential health hazard.

PADOH and ATSDR conclude that with effective dust control measures during excavation andgrading, health effects are not likely either from direct contact with slag or through inhalation offugitive dust. Therefore; the site poses no apparent public health hazard. ATSDR and PADOHrecommend that contractors continue with optimal dust control measures to reduce the possibilityof resident and worker exposures to contaminated media. Additionally, to insure effectiveness ofsuch measures, we also recommend the continuation of periodic, unannounced site inspections during Phase 2 grading by the Allegheny County Health Department.


The Nine Mile Run slag site is a former slag dumping and processing area off Brown's Hill Roadin Pittsburgh, Allegheny County, Pennsylvania, between the Monongahela River and the Penn-Lincoln Parkway East (Interstate Route 376) (Figures 1 and 2). Nine Mile Run flows through thesite from northeast to southwest, dividing it into two sections before emptying into theMonongahela River 300 yards southeast of the property (Figures 2 and 3). The Pittsburgh UrbanRedevelopment Authority (PURA) is developing the site into a planned residential community,now known as Summerset at Frick Park, with three phases of development (Figure 3). As ofSeptember 2002, the Phase 1 area had been brought up to subgrade, and some residential unitswere already completed and occupied [1]. In the late1990s, the EPA and some local citizenswanted to know the potential health impacts of the site as it was being developed. Consequently,a series of six health consultations (HCs) were prepared by PADOH and ATSDR [2, 3, 4, 5, 6,7]. They contain historical information, site descriptions, as well as a voluminous amount ofenvironmental data sets that concentrate particularly on exposure through the air pathway. Previous health consultations addressed possible human health effects of breathing dustgenerated by Phase I grading activities. Using the available soil data in Phase I, ATSDRestimated through dispersion modeling that a maximum air concentration of 52 micrograms percubic meter (ug/m3) for manganese might be created in the work zone without adequate dustcontrol measures [4]. Prolonged exposure at that concentration would pose a potential healththreat to site workers [4].

This HC has been prepared to determine if Phase 2 grading and construction will create apotential health hazard. To make this determination, Phase 2 slag characterization data (June andJuly 2002) was compared to Phase 1 slag data (1995 - 1998) to insure that the contaminantconcentrations were similar. In addition, air quality monitoring data collected before (April 7,1998-June 7, 1999) and during (June 8, 1999-September 3, 2001) Phase 1 construction was alsoevaluated [1].

For Phase 2 slag characterization, the PURA contractor collected 28 slag samples for metals from16 borings and one shallow (grab) sampling location (Figure 4)[1]. Additionally, nine volatileorganic compound (VOC), semi-volatile organic compound (SVOC), and polychlorinatedbiphenyl (PCB) samples from eight borings were collected in various locations within the Phase2 Area. Boring depths ranged from 3 feet to119 feet below the surface[1]. No drums or largevoids were encountered during boring operations. Air samples were collected at four locationsaround the site (Figure 5) for 24 hours a day at varying frequencies (e.g., daily, once in threedays, once in six days) as approved by the Allegheny County Health Department in order toinsure representative sampling over the entire 27 month slag grading period (oral communicationwith Roger Westman, Allegheny County Health Department). Air samples were analyzed forparticulates and heavy metals (see discussion below). The site contractor used dust suppressionmeasures during the Phase 1 grading, and those measures will continueuntil the project iscompleted [1]. In addition to the monitoring, Allegheny County officials regularly inspected siteoperations during Phase 1. Table 1 compares the maximum concentrations of metals,particularly manganese, detected in Phase 1 and Phase 2 slag sampling. Table 2 reports thesummary of air quality data collected during Phase 1 grading as described above and discussed below.


In preparing this HC, ATSDR and PADOH rely on the information provided in referenceddocumentsand conversations. We assume that adequate quality assurance and quality controlmeasures were followed regarding data gathering, chain-of-custody, laboratory procedures, anddata reporting. The analyses, conclusions, and recommendations in this HC are valid only if the referenced documentsare complete and reliable.


In previous HCs, manganese was identified as the main contaminant of concern for the airpathway in Phase 1 because of its toxicity through the inhalation route of exposure and itsrelatively high concentration (maximum concentration of 51,200 milligram per kilogram(mg/kg)) in the slag [1, 5]. The 2002 sampling data indicate the metal content in the slag in thePhase 2 Area is of similar composition to what has been reported in Phase 1 [1, 5]. Table 1shows that the maximum concentrations of most metals (15 of 22) in the Phase 2 pre-gradingslag sampling, including manganese, were lower than those reported in Phase 1. Five metalsshowed higher concentrations, none at levels of health concern. One (arsenic) had a slightlyhigher detection limit than the concentration reported in Phase 1, and one (thallium) was notreported in Phase 1 sampling. The maximum manganese concentration in Phase 2 slag (44,800mg/kg) was lower than that of Phase 1 slag (51,200 mg/kg). Of all the VOCs, SVOCs and PCBssampled, a single sample of benzo(a)pyrene (5.04 ppm) on one occasion exceeded PennsylvaniaDepartment of Environmental Protection (PA DEP) Act 2 standards for residential soil (2.5 ppm)but did not exceed the standard for non-residential soil (11 ppm). Nevertheless, if exposure wereto occur during excavation, the contaminant would be diluted in the air, and the exposure wouldbe of such short duration that the dose would not result in adverse health effects for residentsnear the site. Direct contact exposure to Phase 1 slag was also evaluated in HC No. 4 anddetermined to pose no public health hazard [5]. No newly discovered contaminants werereported in Phase 2 slag sampling at concentrations of health concern. Therefore, exposure to Phase 2 slag through direct contact is not expected to pose a public health hazard.

Average metal concentrations in air during Phase 1 construction are summarized in Table 2. Samples were collected at the four stations and analyzed for total particulates, arsenic,chromium, lead, manganese, nickel, and vanadium. All of the average daily particulateconcentrations were below the federal standard of 50 ug/m3, ranging from 25.5 ug/m3 to 29.8ug/m3 (Table 2) [1]. Furthermore, air contaminant levels during more than two years of Phase 1grading and construction did not violate any federal or local ambient air standards and were wellbelow the daily and annual standards [8]. At one station (Riverview Center), average particulateswere lower during Phase 1 grading (26.5 ug/m3) than during pre-construction monitoring (33.4ug/m3, [1]). However, the average concentration for manganese (0.051 ug/m3) at the Rosemontstation (Figure 5) northwest of the site exceeded ATSDR's chronic minimal risk level (MRL) of0.04 ug/m3 for air (Table 2). Exceeding a comparison value such as an MRL does not imply ahealth hazard exists. Rather, it requires that the contaminant be further evaluated.

The MRL for manganese is based upon a lifetime (70 years) of exposure [9]. The concentrationof 0.04 ug/m3 is a level at which PADOH and ATSDR expect no adverse health effects fromprolonged periods of exposure, up to a lifetime. According to PURA, the total time required forcompletion of all housing units will be about 10 years [1] and therefore, under site specificconditions, overall exposure duration and magnitude would be substantially less than a lifetime. Additionally, the EPA selected reference concentrations (RfC) of 0.05 ug/m3 for manganese isbased on inhalation studies of humans who were occupationally exposed to manganese dioxide[10]. There are safety factors built into these standards, therefore, even if average manganeseconcentrations in air reach the maximum sample concentration of 0.051 ug/m3 over the entiremonitored area until the project ends (a very unlikely scenario), ATSDR and PADOH expect noadverse health effects from inhalation exposures as long as effective dust suppression methods are used.


ATSDR and PADOH recognize that when encountering contaminated soil, air, or water, infantsand children can be more sensitive than adults. Children are smaller than adults, resulting inhigher doses of chemical per unit of body weight. They are shorter, and therefore closer to theground, where they can breathe more dust and heavy vapors. Also, because at certain ageschildren breath more air than adults, there is a concern that children may be more susceptible tothe toxic effects of manganese.Therefore, ATSDR and PADOH have evaluated children'sspecial interests at the Nine Mile Run slag site, and have determined that the site poses no special health risks to children.


PADOH and ATSDR conclude that the Nine Mile Run slag site poses no apparent public health hazard to site workers and nearby residents as long as contractors use appropriate dust control measures during grading and construction. Concentrations of manganese, the contaminant of concern in the slag and airborne dust, even at the maximum reported levels, are not expected to cause adverse health effects over the life of the project (10 years), either through direct contact with slag or inhalation of fugitive dust.


  1. We recommend continued use of dust suppression measures during Phase 2 excavation and grading, or while driving on the site. This action is the responsibility of the PURA site contractor.

  2. We recommend continued random, unannounced site inspections on and near the site during Phase 2 construction to insure that the above recommendation is followed. Compliance inspections will be conducted by the Allegheny County Health Department.

  3. We recommend that (PA DEP) and/or ACHD notify PA DOH regarding changes at the site that might require a health evaluation.


PADOH and ATSDR will continue to evaluate data from The Nine Mile Run slag site as they arepresented for review. PA DOH and ATSDR staff will make this health consultation available toPURA, interested community members and groups, and will be available to answer any questions or concerns.


  1. GAI Consultants, Inc. Final Draft, Pre-Grading Environmental Sampling Report, Phase 2 Area, Nine Mile Run Development, Pittsburgh, Pennsylvania. September 2002.

  2. Agency for Toxic Substances and Disease Registry. Health Consultation No. 1, Nine Mile Run Slag Area, Pittsburgh, Allegheny County, Pennsylvania. Atlanta: ATSDR, September15, 1998.

  3. Agency for Toxic Substances and Disease Registry. Health Consultation No. 2, Nine Mile Run Slag Area, Pittsburgh, Allegheny County, Pennsylvania. Atlanta: ATSDR, April 7,1999.

  4. Agency for Toxic Substances and Disease Registry. Health Consultation Air Pathway Dose Reconstruction, Nine Mile Run Slag Area, Pittsburgh, Allegheny County, Pennsylvania. Atlanta: ATSDR, May 5, 1999.

  5. Agency for Toxic Substances and Disease Registry. Health Consultation No. 4, Nine Mile Run Slag Area, Pittsburgh, Allegheny County, Pennsylvania. Atlanta: ATSDR, June 29, 1999.

  6. Agency for Toxic Substances and Disease Registry. Health Consultation No. 5, Nine Mile Run Slag Site, City of Pittsburgh, Allegheny County, Pennsylvania. Atlanta: ATSDR, March 22, 2000.

  7. Agency for Toxic Substances and Disease Registry. Health Consultation No. 6, Nine Mile Run Slag Site, City of Pittsburgh, Allegheny County, Pennsylvania. Atlanta: ATSDR, August 9, 2000.

  8. Letter from Roger C. Westman, Allegheny County Health Department, to Jerome N. Dettore, P.E., PURA. August 20, 2001.

  9. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Manganese - Draft for Public Comment (Update), U.S. Public Health Service. Atlanta, Georgia: ATSDR, September 1997.

  10. United States Environmental Protection Agency. Integrated Risk Information System (IRIS) Database. October 2000.


Pennsylvania Department of Health
Health Assessment Program
Division of Environmental Health Epidemiology

J.E. Godfrey, P.G.
Pennsylvania Department of Health

Christine Brussock, MS
Program Manager


Table 1. Comparison of Maximum Metals Concentrations
Phase I (1995 - 1998) vs Phase II (June, July, Aug 2002)
Pre-Grading Sampling

Aluminum 23,800 45,700
Antimony 35.7 <4.8
Arsenic 3.54 <4.8
Barium 249 493
Beryllium 4.05 2.65
Boron 613 588
Cadmium 15.2 0.964
Chromium III 3,120 1,360
Cobalt 20.4 12.7
Copper 401 138
Iron 336,000 207,000
Lead 101 117
Manganese 51,200 44,800
Mercury 0.08 0.0575
Nickel 88 33.2
Selenium 7.5 <4.8
Silver 8.57 77.5
Thallium NR 21.3
Tin 7.8 20.5
Vanadium 986 339
Zinc 749 470
Chromium VI 94 53.4

NR = Not Reported


Sampling Location Concentration (ug/m3)
PM10(1) Arsenic(2) Chromium(2) Lead(2) Manganese(3) Nickel(2) Vanadium(2)
Riverview Center 26.5 0.015(4) 0.006(4) 0.018(4) 0.036(4) 0.005(4) 0.003(4)
Duck Hollow 26.6 0.020(4) 0.005(4) 0.018(4) 0.032(4) 0.005(4) 0.004(4)
Rosemont 29.8 0.016(4) 0.005(4) 0.019(4) 0.051(4) 0.004(4) 0.003(4)
Swisshelm Park/Radio Towers 25.5 0.011(4) 0.005(4) 0.017(4) 0.035(4) 0.004(4) 0.003(4)


(1) PM10 concentrations are the results from Hi-Volume samplers with collection on glass fiber filters with gravimetric analysis.

(2) Metal concentrations are for the period June 6, 1999 through January 31, 2000.

(3) Manganese concentrations are for the period June 6, 1999 through April 31, 2001.

(4) Averages calculated with results reported as less than the limit of detection used one-half of the less than value in the calculation.

ATSDR chronic MRL for manganese in air = 0.04 µg/m3

Federal Standards for PM10: Annual Average
Daily (24 hour average)
50 ug/m3
150 ug/m3
Standards for Lead: 3-Month Average 1.5 ug/m3
ACHD Standard for Lead: 8-Hour Average 10 ug/m3

Air monitoring and analysis were conducted following USEPA Reference Method, "Reference Method for the Determination of Particulate Matter as PM10 in the Atmosphere" (40 CFR Part 50, Appendix J).


Site Location Map
Figure 1. Site Location Map

Site Location Map
Figure 2. Site Location Map

Site Location Map
Figure 3. Site Location Map

Metals Analysis Sample Locations
Figure 4. Metals Analysis Sample Locations

Air Monitor Location Plan
Figure 5. Air Monitor Location Plan


This Health Consultation for the Nine Mile Run Site was prepared by the Pennsylvania Department of Health under a cooperative agreement with the federal Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation was initiated.

LCDR Alan G. Parham, REHS, MPH
Technical Project Officer, SPS, SSAB DHAC

The Division of Health Assessment and Consultation (DHAC), ATSDR, has reviewed this health consultation and concurs with its findings.

Roberta Erlwein
Section Cheif, SPS, SSAB, DHAC, ATSDR

Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

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