Remedial Investigation 

Many Diversified Interests, Inc. Superfund Site 

Operable Unit 3 

Houston, Harris County, Texas 

Remedial Action Contract 2 Full Service 

Contract: EP-W-06-004 

Task Order: 0026-RICO-06CN 

Prepared for 

U.S. Environmental Protection Agency 

Region 6 

1445 Ross Avenue 

Dallas, Texas 75202-2733 

Prepared by 

EA Engineering, Science, and Technology, Inc. 

405 S. Highway 121 

Building C, Suite 100 

Lewisville, Texas 75067 

(972) 315-3922 

April 2009 

Revision: 02 

EA Project No. 14342.26 

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Contents, Page 1 of 2 

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Many Diversified Interests Operable Unit 3 Remedial Investigation Report 

Houston, Harris County, Texas Revision 02 

CONTENTS 

Page

1. INTRODUCTION .....................................................................................................................1

1.1 PURPOSE ..........................................................................................................................1

1.2 SCOPE ...............................................................................................................................1

2. BACKGROUND .......................................................................................................................3

2.1 SITE HISTORY .................................................................................................................3

2.2 SITE DESCRIPTION ........................................................................................................4

2.3 PREVIOUS INVESTIGATIONS ......................................................................................5

2.3.1 2003 Removal Action .............................................................................................7

2.3.2 2005 Removal Action .............................................................................................8

2.3.3 2006 Removal Action .............................................................................................8

2.3.4 OU 1 Remedial Action ............................................................................................8

3. REMEDIAL INVESTIGATION ACTIVITIES ........................................................................9

3.1 RECONNAISSANCE AND PROPERTY ACCESS .........................................................9

3.1.1 Residential Crawlspaces .........................................................................................9

3.1.2 Residential Yards ..................................................................................................10

3.2 QUALITATIVE DOOR-TO-DOOR SURVEYS ............................................................10

3.3 SAMPLE COLLECTION SUMMARY ..........................................................................11

3.3.1 Residential Crawlspace Soil Sampling .................................................................12

3.3.2 XRF Testing of Exterior Paint ..............................................................................13

3.3.3 Residential Yard Soil Sampling ............................................................................13

3.3.4 Residential Drip Zone Soil Sampling ...................................................................14

3.3.5 Personal Air Monitoring and Sampling ................................................................14

3.3.6 Personnel Blood-Lead Testing ..............................................................................15

3.4 DOCUMENTATION OF FIELD ACTIVITIES .............................................................15

3.5 SAMPLE DESIGNATION ..............................................................................................15

3.6 SAMPLE PROCESSING .................................................................................................16

3.6.1 Residential Yard and Crawlspace Soil (0 - 1 inch bgs) ........................................16

3.6.2 Residential Yard Soil (0 - 6, 6 - 12, and 12 - 18 inches bgs) ................................17

3.6.3 Residential Yard and Crawlspace Soil Sample Preparation for Analysis .............18

3.6.4 Residential Drip Zone Soil Sample Processing ....................................................18

3.7 SAMPLING HANDLING AND CUSTODY PROCEDURES .......................................18

3.8 DATA ANALYSIS AND VALIDATION ......................................................................19

3.8.1 XRF versus Laboratory Evaluation ......................................................................19

3.8.2 Sieved versus Unsieved Soil Fractions ................................................................20

3.8.3 Sieved Crawlspace versus Sieved Yard Soil Fractions .........................................21

3.8.4 Field Duplicates ....................................................................................................22

3.8.5 Equipment Rinsate Blanks ....................................................................................22

3.9 WORK PLAN DEVIATIONS .........................................................................................22

4. NATURE AND EXTENT OF SOIL CONTAMINATION ....................................................24

4.1 SOIL CONTAMINATION ..............................................................................................24

4.1.1 Residential Crawlspace Soil .................................................................................25

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4.1.2 Residential Yard Soil (0 – 18 inches bgs) .............................................................25

4.2 SOURCE EVALUATION ...............................................................................................25

4.2.1 Site Geology ..........................................................................................................26

4.2.2 Historic Land Use .................................................................................................26

4.2.3 Potential Sources of Lead .....................................................................................26

4.2.4 EPA NERL Source Evaluation (OU 1 and OU 2) ................................................26

4.2.5 OU 3 Source Evaluation .......................................................................................28

4.3 HEALTH AND SAFETY ................................................................................................30

4.3.1 Air .........................................................................................................................30

4.3.2 Blood Lead ............................................................................................................31

5. HUMAN HEALTH RISK ASSESSMENT .............................................................................32

5.1 DETERMINISTIC RISK ASSESSMENT ......................................................................33

5.1.1 Deterministic Residential Yard Soil with No Crawlspace Exposure ....................34

5.1.2 Deterministic Residential Yard Soil with Hypothetical Crawlspace 

Exposure Using a Time-Weighted Average Approach ........................................35

5.1.3 Deterministic Neighborhood Risk Evaluation with and without 

Hypothetical Crawlspace Exposure Using a Time-Weighted Average 

Approach ...............................................................................................................36

5.1.4 Deterministic Residential Yard Soil for the Single Residence (Cage022) 

where the Survey Indicated Children were Playing in the Crawlspace ................37

5.1.5 Deterministic Sensitivity Evaluation to Evaluate Preliminary Remediation 

Goals for Crawlspaces ..........................................................................................38

5.2 PROBABILISTIC RISK ASSESSMENT .......................................................................39

5.3 UNCERTAINTY SUMMARY ........................................................................................40

5.4 HHRA SUMMARY .........................................................................................................40

5.4.1 Deterministic Risk Evaluation Summary ..............................................................40

5.4.2 Probabilistic Risk Evaluation Summary ...............................................................41

6. CONCLUSIONS......................................................................................................................43

6.1 CONCEPTUAL SITE MODEL .......................................................................................43

6.2 REMEDIAL INVESTIGATION CONSIDERATIONS ..................................................43

6.3 RISK ASSESSMENT CONSIDERATIONS ..................................................................44

6.3.1 Deterministic Evaluation ......................................................................................44

6.3.2 Probabilistic Evaluation ........................................................................................45

6.4 SUMMARY .....................................................................................................................46

REFERENCES 

GLOSSARY 

APPENDIX A ACCESS AGREEMENTS 

APPENDIX B SUMMARY OF QUALITATIVE DOOR-TO-DOOR SURVEYS 

APPENDIX C RESIDENTIAL PROPERTY SKETCHES 

APPENDIX D ANALYTICAL DATA SUMMARY TABLES 

APPENDIX E RESULTS OF STATISTICAL ANALYSIS OF SOIL DATA 

APPENDIX F FIXED LABORATORY DATA PACKAGES 

APPENDIX G ELECTRONIC DATA 

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TABLES 

1 Summary of Properties (Yards) Addressed During Previous Investigations and 

Removal Actions (1999 – 2006) 

2 Summary of Property Access and Sampling for Residential Crawlspaces 

3 Summary of Property Access and Sampling for Residential Yards and High-Access 

Areas 

4 Summary of Screening Criteria 

5 Lead Concentrations Exceeding 463 mg/kg for Operable Unit 3 Residential Yards 

6 Comparison of Lead Concentrations in Exterior Paint and Corresponding 

Crawlspace Soil 

7A Deterministic IEUBK Model Results Summary for OU 3 Residential Areas 

7B Deterministic IEUBK Model Results Summary for OU 3 Residential Areas after 

Scheduled Removal Action 

8A Deterministic IEUBK Model Results Summary for OU 3 Residential Yard and 

Crawlspace Areas (2 Days per Week Exposure Frequency) 

8B Deterministic IEUBK Model Results Summary for OU 3 Residential Yard and 

Crawlspace Areas after Scheduled Removal Action (2 Days per Week Exposure 

Frequency) 

9 Deterministic Time-Weighted Average Soil Lead Concentration for OU 3 Residential 

Yard Soil Samples (Variable Exposure Frequency) 

10 Deterministic Crawlspace Preliminary Remediation Goals for OU 3 Residential Yard Soil 

Samples (1 Day per Week Exposure) 

11 Deterministic Crawlspace Preliminary Remediation Goals for OU 3 Residential Yard Soil 

Samples (2 Days per Week Exposure) 

12 Deterministic Crawlspace Preliminary Remediation Goals for OU 3 Residential 

Yard Soil Samples (3 Days per Week Exposure) 

13 Summary of Crystal Ball Model Results—Exposure Point Concentration Forecast 

14 Summary of Crystal Ball Model Results—Crawlspace Clean-up Goal Forecast 

15 Summary of Properties Addressed During EPA and TNRCC Removal Actions 

(1999 – 2009) 

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FIGURES 

1 Site Location Map 

2 Summary of Previous EPA and TCEQ Activities 

3 OU 3 Residential Yard Sampling Summary 

4 Typical Domino Configurations for Collecting Residential/Crawlspace Surface Soil 

Samples 

5 Residential Soil Profile and Sampling Design 

6 OU 3 Crawlspace Sampling Summary and Results 

7 Residential Yard Sampling Results 

8 Exposure Pathways 

9 Integrated Exposure Uptake Biokinetic (IEUBK) Lead Model Process Flow Chart

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LIST OF ACRONYMS AND ABBREVIATIONS 

μg/dL microgram(s) per deciliter 

μm micrometer(s) 

Agreed Order Agreed Order on Consent and Covenant Not to Sue 

bgs below ground surface 

Bruce Blanche Kelso Bruce 

CD compact disc 

CGI Clinton Gregg Investments, L.P. 

COC contaminant of concern 

CSM Conceptual Site Model 

DESR Data Evaluation Summary Report 

DQO data quality objective 

EA EA Engineering, Science, and Technology, Inc. 

ENTACT ENTACT Environmental Services 

EPA U.S. Environmental Protection Agency 

EPC exposure point concentration 

FAI FAI Materials Testing Laboratory 

FS Feasibility Study 

ft2 Square foot (feet) 

g/m2-year gram(s) per square meter per year 

GPS Global Positioning System 

HCAD Harris County Appraisal District 

HHRA Human Health Risk Assessment 

HSP Health and Safety Plan 

HUD Department of Housing and Urban Development 

I-10 U.S. Interstate Highway 10 

IEUBK Integrated Exposure Uptake Biokinetic 

LTS least trimmed squares 

MDI Many Diversified Interests 

mg/cm2

 milligram(s) per square centimeter 

mg/kg milligram(s) per kilogram 

mm millimeter(s) 

MSSL Medium Specific Screening Level 

NERL-LV National Exposure Research Laboratory in Las Vegas, Nevada 

NIOSH National Institute for Occupational Safety and Health 

OSHA Occupational Safety and Health Administration 

OSWER Office of Solid Waste and Emergency Response 

OU Operable Unit 

PM particulate matter 

PRG preliminary remediation goal 

QC quality control 

r

2 coefficient of determination 

RA Remedial Action 

RI Remedial Investigation 

RSL Regional Screening Level 

ROD Record of Decision 

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LIST OF ACRONYMS AND ABBREVIATIONS (Continued) 

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SAP Sampling and Analysis Plan 

SEM scanning electron microscopy 

SOW Statement of Work 

SRI Superfund Redevelopment Initiative 

START-2 Superfund Technical Assessment and Response Team 2 

TCEQ Texas Commission on Environmental Quality 

TESCO Texas Electric Steel Casting Company 

TNRCC Texas Natural Resource Conservation Commission 

TWA time-weighted average 

XRF X-ray fluorescence 

yd3

 cubic yard(s) 

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Many Diversified Interests Operable Unit 3 Remedial Investigation Report 

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1. INTRODUCTION 

This document presents the Remedial Investigation (RI) conducted by EA Engineering, Science, 

and Technology, Inc. (EA) for Operable Unit (OU) 3 of the Many Diversified Interests (MDI) 

Superfund Site located in Houston, Harris County, Texas. EA performed the RI for the U.S. 

Environmental Protection Agency (EPA) Region 6 as part of Task Order No. 0026-RICO-06CN 

under EPA Contract No. EP-W-06-004, in accordance with a Statement of Work (SOW) issued 

by EPA (EPA 2007b). This Task Order addresses the RI and Feasibility Study (FS) for OU 3, 

which includes residential crawlspaces and those residential areas that have not been addressed 

during previous investigations (OU 1 and OU 2). The EPA RI/FS SOW (EPA 2007b) and Task 

Order Work Plan (EA 2008a) set forth the framework and requirements for this effort. 

The OU 3 RI field program was conducted in accordance with the following site-specific plans: 

• Health and Safety Plan (HSP) (EA 2007a) 

• Site Management Plan (EA 2007b), which includes the following elements: 

– Pollution Control and Mitigation Plan 

– Data Management Plan 

• Sampling and Analysis Plan (SAP) (EA 2007c), which includes the following elements: 

– Data Quality Objectives (DQO) Technical Memorandum 

– Conceptual Site Model (CSM). 

1.1 PURPOSE 

The purpose of this RI Report is to present all of the data collected and evaluated during the RI 

so that the nature and extent of lead contamination in OU 3 soil can be estimated. The Data 

Evaluation Summary Report (DESR; EA 2008b) summarizes the analytical data quality and 

usability in relation to the project-specific DQOs presented in the site-specific SAP for OU 3. 

The nature and extent of contamination that may pose risk to human health are presented in the 

Human Health Risk Assessment (HHRA) Report for OU 3 (EA 2009). The information 

provided in this RI Report and the HHRA Report will then be used to evaluate remedial/removal 

action alternatives designed to eliminate, reduce, or control these risks. Ultimately, the RI data 

will be used to prepare the Record of Decision (ROD) for MDI OU 3. 

1.2 SCOPE 

This Task Order addresses the RI/FS for OU 3, which includes residential crawlspaces and those 

residential areas that were not addressed during previous RIs (OU 1 and OU 2). The purpose of 

the RI/FS is to determine the nature and extent of lead contamination and to gather sufficient 

information so that the EPA can select a remedy that eliminates, reduces, or controls risks to 

human health. Specifically, the RI/FS involves the investigation and study of OU 3 (i.e., 

residential crawlspaces and the residential areas not addressed under OU 2). The contaminant of 

concern (COC) for OU 3 is lead in soil. 

EA has implemented the following key components during the RI/FS for OU 3: 

 

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• Area Reconnaissance/Interviews—Reconnaissance activities and qualitative surveys were 

performed for the following purposes:

⎯ Confirm the status of residential properties addressed during the OU 2 RI/FS and 

removal actions.

⎯ Determine the location/status of residential properties for the OU 3 RI/FS.

⎯ Identify which of the OU 3 residential properties have crawlspaces.

⎯ Determine whether residential crawlspaces are accessible to children and/or pets. 

⎯ Obtain site access to properties to be investigated during the OU 3 RI/FS. 

⎯ Survey residents for information that will be used in the HHRA. 

• Data Collection—During the OU 3 field program, the following samples were collected: 

⎯ Soil samples for lead analysis from OU 3 residential properties not addressed during 

the OU 2 RI/FS and removal actions. 

⎯ Soil samples for lead analysis from the crawlspaces of OU 3 residences and 

Background Study Area residences. 

⎯ Soil samples from crawlspaces and paint chip samples from corresponding structure 

locations for lead speciation analyses. 

• Risk Assessment—HHRA was conducted to characterize and quantify the current and 

potential human health effects that would prevail, if no further remedial action is taken. 

The Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in Children (EPA 

1994, 2007a) was used in the determination of risk to children from exposure to soils in 

the crawlspaces and residential yards. The most recent updated dietary lead intake 

estimates for each age category was used in the IEUBK Model. EA performed 

deterministic and probabilistic risk analyses based on the lead-soil exposure point 

concentration. The EPA OU2 removal action level was used in a weight of evidence 

approach in conjunction with the output from the IEUBK Model to determine residences 

that may be subject to a remedial decision (based on EPA’s discretion). Site-specific 

clean-up levels were developed for crawlspaces using probabilistic evaluation of 

exposure, which included a “Monte Carlo” analysis. 

• RI Report—RI Report presents the findings utilizing data collected as part of the OU 3 

RI. 

These components are detailed in the following sections: 

• Section 2.0 – Background 

• Section 3.0 – Remedial Investigation Activities 

• Section 4.0 – Nature and Extent of Soil Contamination 

• Section 5.0 – Human Health Risk Assessment 

• Section 6.0 – Conclusions. 

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2. BACKGROUND 

This section contains a summary of the site history, key investigations, and project milestones for 

MDI OU 3. 

2.1 SITE HISTORY 

The former foundry, also known as Texas Electric Steel Casting Company (TESCO), occupies a 

36-acre tract of land located at 3617 Baer Street in Houston, Texas (Figure 1). The MDI site is 

located approximately 2 miles east of downtown Houston and 1 block south of U.S. Interstate 

Highway 10 (I-10) in an area of mixed industrial and residential land use. This part of Houston 

is known as the “Fifth Ward.” The MDI property is bounded by Hare Street to the north, 

National Vinegar Company and Press Street to the east, the former Texas & New Orleans 

railroad right-of-way beyond the easement to the south, and Bringhurst Street to the west. 

Residential areas are adjacent to the east, west, and north sides of the site. Industrial areas are 

adjacent to the south side of the site. The MDI site includes the residential yards or properties 

and high-access areas surrounding the former foundry. High-access areas include schools, child 

daycare centers, playgrounds, and churches that surround the fenced boundaries of the site. 

In 1926, TESCO began operations as a metal casting foundry at the MDI site. A second foundry 

was built on the eastern portion of the site during the latter half of 1970. TESCO primarily 

manufactured specialty molded parts such as large wheels, tracks, and mining equipment. 

Various grades of steel, including high carbon, chrome molybdenum, high nickel, and stainless 

steel were cast at the TESCO facility. During the mid-1980s, the southern portion of the site was 

leased to Can-Am Resource Group, which conducted a spent catalyst recycling operation. In 

1990, MDI bought the TESCO note from Texas Commerce Bank. TESCO ceased operations in 

February 1991 and MDI foreclosed on the property. MDI reopened as San Jacinto Foundry on 

1 March 1991, and operated the facility for just over a year before declaring bankruptcy (TTEMI 

2005b). 

The onsite facilities were demolished as a salvage operation under order of the U.S. Bankruptcy 

Court between March 1995 and January 1996. Following the salvage operation, the only 

structures remaining on the MDI site included concrete foundations from several demolished 

foundry buildings, a laboratory and administration building, a railroad boxcar used as a former 

storage building, a large melt transformer in the northwest corner of the site, and several concrete 

structures formerly used as vats. 

EPA believes that the air emissions from the former foundry, which contained particles of lead, 

may have caused the on and offsite soils to become contaminated through the air deposition of 

these particles. Foundry practices may have also contributed to the onsite lead contamination of 

the soils. Other probable sources of lead contamination that may have impacted the on- and 

offsite soils may include lead-based paint and historical deposition from vehicular lead-based 

fuel emissions, among other possible sources. 

The MDI offsite area was originally a concern due to the stacks and blowers that operated on 

site, as well as fugitive emissions. Information in the Texas Commission on Environmental 

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Quality’s (TCEQ; formerly the Texas Natural Resource Conservation Commission [TNRCC]) 

permit files indicates that there were three furnaces onsite, which were ducted to one or two 

stacks. 

2.2 SITE DESCRIPTION 

Land use surrounding the MDI site is a mixture of residential and industrial. Blanche Kelso 

Bruce (Bruce) Elementary School was formerly located adjacent to and west of the site; it has 

since been reconstructed at a new location west of the site and outside of the Modeled Air 

Deposition Area and East Blower Area (also known as the Study Area). Residential areas are 

located adjacent to the site; there are an estimated 942 housing units and approximately 

2,756 people within 1⁄2 mile of the site (TTEMI 2005b). Figure 2 shows the site boundary, the 

Modeled Air Deposition Area, the East Blower Area, and the surrounding residential area. 

Operable unit means a discrete action that comprises an incremental step toward 

comprehensively addressing problems at a site. This discrete portion of a remedial response 

manages migration, or eliminates or mitigates a release, threat of a release, or pathway of 

exposure. The clean-up of a site can be divided into a number of OUs, depending on the 

complexity of the problems associated with a site. OUs may address geographical portions of a 

site, specific site problems, or initial phases of an action, or may consist of any set of actions 

performed over time or any actions that are concurrent but located in different parts of a site. 

OUs will not impede implementation of subsequent actions, including final action at a site. 

The MDI site is comprised of the following OUs (Figures 1 and 2): 

• OU 1 (Onsite Soils and Ground Water)―Fenced boundary of the former 36-acre foundry 

located at 3617 Baer Street in Houston, Texas; located approximately 2 miles east of 

downtown Houston and 1 block south of I-10 in an area of mixed industrial and 

residential land use known as the “Fifth Ward.” 

• OU 2 (Offsite Residential Yards and High-access Areas)―Residential yards or properties 

and high-access areas that surround the east, west, and north fenced boundaries of the 

former foundry (OU 1), and located within the Modeled Air Deposition Area and East 

Blower Area (Study Area). High-access areas include schools, child daycare centers, 

playgrounds, and churches. 

• OU 3 (Residential Crawlspaces and those Residential Areas Not Addressed under 

OU 2)―Residential crawlspaces, residential yards or properties, and high-access areas 

located within the Modeled Air Deposition Area and East Blower Area (Study Area) that 

were not addressed during previous RI/FS activities and removal actions conducted for 

MDI. 

This Task Order addresses the RI/FS for OU 3, which includes residential crawlspaces and those 

residential and high-access areas not addressed under OU 2 that are located within the Modeled 

Air Deposition Area and East Blower Area (Study Area). The Modeled Air Deposition Area is 

defined as the modeled air deposition area bound by the 400-milligrams per kilogram (mg/kg) 

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lead isopleth shown in Figure 2. The reported East Blower Area is located to the east of OU 1 

(i.e., the fenced boundaries of the former foundry). 

During the OU 2 RI, air quality impact modeling was conducted to predict where (1) particulate 

matter from historical stack emissions would have been deposited onto the ground surface, and 

(2) soil-lead concentrations may potentially meet or exceed the EPA Region 6 Human Health 

Medium-specific Screening Levels (MSSLs) for heavy metals associated with foundry activities 

(TTEMI 2005a). The preliminary air quality impact modeling study that was developed for the 

OU 2 RI is based on a number of conservative input parameters regarding emission controls and 

lead concentrations in feedstock during historic foundry operations. These assumptions were 

necessitated by the limited historical information regarding site operations. The planning-level 

modeling that was performed resulted in the delineation of contours (isopleths) with different 

estimates of deposition rates corresponding to different total lead concentrations: 

• At the 1.8 grams per square meter per year (g/m2

-year) isopleth, the lead concentration is 

expected to be about 1,600 mg/kg (immediate vicinity of the site [OU 1]). 

• Between the 0.8 and 1.8 g/m2

-year isopleths, the lead concentration is expected to be 

greater than 400 mg/kg, but less than 1,600 mg/kg (concentration decreases with 

increasing distance from the site). 

• Beyond the 0.8 g/m2

-year isopleth, the lead concentration is expected to be less than 400 

mg/kg. 

During the 2003 OU 2 RI, all residences within the predicted impact area corresponding to lead 

concentrations ranging greater than 400 mg/kg (outer boundary of Modeled Air Deposition Area) 

to 1,600 mg/kg (immediate vicinity of the MDI site), as expressed by the 0.8 g/m2

-year isopleth 

(see Figure 2), were targeted for sampling. Any impact from blowers reported to have operated 

on the east side of the site may not have been fully accounted for in the air dispersion model; 

therefore, properties east of Press Street (offsite East Blower Area) were also included in the OU 

2 RI. 

During the 2008 OU 3 RI, EPA targeted those residential crawlspaces, residential yards or 

properties, and high-access areas located within the Modeled Air Deposition Area and East 

Blower Area (Study Area) that were not addressed during previous RI/FS activities and removal 

actions conducted for the MDI site. 

The OU 3 investigation was designed to determine the nature and extent of lead contamination 

and to gather sufficient information so that the EPA can select a remedy that eliminates, reduces, 

or controls risks to human health (EA 2007c). This RI Report specifically addresses OU 3. 

2.3 PREVIOUS INVESTIGATIONS 

In January 1996, EPA and TCEQ (formerly TNRCC) collected soil samples from five residences 

in the offsite MDI area; all samples contained lead exceeding the action level of 500 mg/kg. 

Between February and July 1996, EPA collected 100 soil samples from yards and vacant lots; 

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41 of the properties had lead concentrations greater than 500 mg/kg. During the summer of 

1998, TCEQ identified an additional 48 properties with lead concentrations greater than or equal 

to 500 mg/kg. In 1999, TCEQ conducted a removal and restoration of the 89 residential yards 

with lead concentrations greater than or equal to 500 mg/kg (Eagle Construction & 

Environmental Services, L.P. 1999) (Figure 2). The removal action was conducted to reduce the 

exposure of children and adults to lead. 

In September 1999, the Mayor’s Office of Environmental Policy (City of Houston) received a 

Superfund Redevelopment Initiative (SRI) Grant. The City of Houston was selected to receive 

one of 10 pilot grants being awarded nationwide under the EPA’s innovative SRI. The City 

received $100,000 to conduct a reuse assessment and public outreach to help determine how best 

to redevelop the former MDI property in the Fifth Ward. The MDI Citizen Advisory Group, in 

the “Reuse Assessment Report,” recommended reuse of the site for mixed residential, organized 

recreational, and neighborhood-scale commercial uses. 

During the RI performed in 2003 (OU 1 and OU 2), residential properties and high-access areas 

within the Modeled Air Deposition Area, bound by the 400-mg/kg lead isopleths, and the East 

Blower Area (located to the east of OU 1) were evaluated and sampled (Figure 2). Table 1

summarizes the property types and quantities that were addressed during the 2003 OU 2 RI. 

In addition, 23 residential crawlspaces were also sampled per EPA direction to evaluate lead 

concentrations; 6 of the 23 crawlspaces sampled during the 2003 RI were located outside and 

west of the Modeled Air Deposition Area. 

On 30 July 2004, EPA issued a ROD for the onsite portion of the MDI site, or OU 1 (Onsite 

Soils and Ground Water) (EPA 2004). The remedy included the following major components: 

• Excavation and treatment (solidification/stabilization, if necessary) of approximately 

13,600 cubic yards (yd3

) of soils with lead concentrations equal to or greater than 500 

mg/kg to a maximum depth of 11⁄2 feet below ground surface (bgs), and approximately 

3,000 yd3 of soils stockpiled within OU 1 from a previous removal action; transportation 

and disposal of the treated and untreated soils at a permitted offsite waste disposal 

facility. 

• Transportation and disposal of approximately 31,621 yd3

 of debris (nonhazardous debris, 

foundry sand, and slag), asbestos-containing material, and an underground storage tank at 

a permitted offsite waste disposal facility. 

• Excavation and disposal of approximately 2,100 yd3

 of soils contaminated with 

polycyclic aromatic hydrocarbons, light non-aqueous phase liquids, and total petroleum 

hydrocarbons at a permitted offsite waste disposal facility. 

• Implementation of monitored natural attenuation for impacted ground water, which 

includes source removal and long-term monitoring for the ground water to ensure that 

constituents above clean-up goals are naturally attenuating. 

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• Implementation of institutional controls for both the soils and ground water to prevent 

exposure to soil contamination above acceptable clean-up levels and to prevent exposure 

to contaminated ground water in the shallow water-bearing zone. 

On 22 March 2005, the bankruptcy trustee for the MDI property, represented by Waldron & 

Schneider, LLP, auctioned the 36 acres of property (OU 1) for a total sales price of $7,897,539. 

On 23 September 2005, EPA issued a ROD for OU 2 (Offsite Residential Yards and High-access 

Areas) (EPA 2005a). EPA’s final remedy decision for OU 2 was “no further remedial action,” 

since previous removal actions had eliminated the existing and potential risks to human health 

and the environment, so that no further action was necessary. The purpose of the removal 

actions was to remove surface soil with concentrations of lead that equaled or exceeded the 

clean-up goal of 500 mg/kg to reduce the exposure of children and adults to lead. These removal 

actions addressed all of the residential yards and high-access areas that could have been impacted 

by the emission of particulates containing lead from the former foundry, and for which the EPA 

was granted access for sampling. Sections 2.3.1 through 2.3.3 provide additional detail 

regarding the EPA removal actions. 

On 26 May 2006, the purchaser for the MDI property (OU 1; area within the fenced boundaries 

of the former foundry), Clinton Gregg Investments, L.P. (CGI), signed an “Agreed Order on 

Consent and Covenant Not to Sue” (Agreed Order). The Agreed Order for OU 1 became final 

on 29 September 2006 (EPA 2006), and directed CGI to implement the remedy identified in the 

ROD for OU 1 in accordance with the requirements of the Agreed Order. Section 2.3.4 provides 

additional detail regarding the OU 1 Remedial Action (RA). 

2.3.1 2003 Removal Action 

Lead data collected during the OU 2 RI indicated that several residences, as well as the former 

Bruce Elementary School, had lead concentrations exceeding the action level for the 1999 TCEQ 

removal action. From July through November 2003, EPA performed removal actions targeting 

the former Bruce Elementary School (reconstructed at a new location) and residential yards with 

lead concentrations greater than or equal to 500 mg/kg (minus a standard deviation of 37 mg/kg 

[or 463 mg/kg]) under the Superfund Technical Assessment and Response Team 2 (START-2) 

contract. The START-2 contractor excavated and restored 37 residential properties, and 17 

vacant lots, portions of an elementary school, a community center, and a church (Weston 2004). 

X-ray fluorescence (XRF) was used to analyze residential soil samples for lead (see Section 3.0). 

Although the clean-up goal was set at 500 mg/kg, which is equal to the Texas Risk Reduction 

Program Tier 1 Protective Concentration Level, the practical clean-up level was set at 463 

mg/kg. This lower value takes into account the average relative standard deviation for the XRF 

instrument of ±37 mg/kg, a measure of the precision of the Niton® portable XRF analyzer. The 

average relative standard deviation was determined by averaging the reported instrument error 

values associated with field XRF lead analysis for all residential soil samples analyzed. 

Therefore, any property with reported lead concentrations in soil greater than 463 mg/kg (or 500 

mg/kg minus 37 mg/kg) was considered to be in exceedance of the clean-up level as a 

conservative measure. 

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The action level for lead in soils (463 mg/kg) was determined to be protective of human health 

based on IEUBK modeling of actual data collected from other EPA Region 6 Superfund sites, 

namely RSR Corporation Superfund Site (EPA 1995), Tar Creek Superfund Site (EPA 1997), 

and Delatte Metals Superfund Site (EPA 2000b). 

2.3.2 2005 Removal Action 

During May and June 2005, a second EPA removal action was performed under the START-2 

contract. The removal action was performed at five properties with lead concentrations in soil 

greater than 463 mg/kg that were not previously addressed during the 2003 EPA removal action 

(Figure 2). Two of the five properties had been addressed during the 2003 removal action, but 

required additional remediation based on subsequent data evaluation. A total of 308 yd3

 of 

contaminated soil was removed from the five properties (Weston 2005). 

2.3.3 2006 Removal Action 

From February through April 2006, a third EPA removal action was performed at the Kelly 

Village Housing Authority Property. Lead-contaminated soil was excavated from nine grids 

within the multi-family housing unit from depths ranging from 6 inches to 2 feet bgs, depending 

on the depth of lead contamination as determined during the 2003 RI/FS. During the removal 

operations, approximately 1,760 yd3

 of lead-contaminated soil was excavated (Weston 2006). 

More detailed information concerning the 2003, 2005, and 2006 EPA removal actions is 

available in the final reports submitted to EPA by its START-2 contractor, Weston Solutions, 

Inc. (Weston 2004, 2005, 2006). 

Table 1 summarizes the property types and quantities that were addressed during previous EPA 

and TCEQ (formerly TNRCC) investigations and removal actions associated with the MDI site 

(1996 – 2006). 

2.3.4 OU 1 Remedial Action 

Under the Agreed Order for OU 1 (EPA 2006), CGI agreed to implement the remedy identified 

in the ROD for OU 1. ENTACT Environmental Services (ENTACT) implemented the RA at 

OU 1 on behalf of the purchaser beginning in February 2007. The RA for OU 1 is complete 

pending final approval from EPA. 

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3. REMEDIAL INVESTIGATION ACTIVITIES 

The OU 3 RI activities were performed between January and August 2008. The main objective 

of the OU 3 RI was to determine the nature and extent of lead contamination and to gather 

sufficient information so that the EPA can select a remedy that eliminates, reduces, or controls 

risks to human health. 

The following sections describe field activities as well as the analytical program and data 

validation processes implemented at the MDI site during the OU 3 RI. 

3.1 RECONNAISSANCE AND PROPERTY ACCESS 

Sampling activities for the OU 3 RI were performed on private properties; therefore, a significant 

effort was required to gain access to all of the potentially affected properties. Property 

ownership records were reviewed at the Harris County Appraisal District (HCAD) office. 

Letters describing the project and property access agreements requiring consent signatures were 

mailed to property owners. Follow-on calls were made to ascertain the status of these 

agreements, and face-to-face interviews were conducted with most property owners, when 

requested. For many of the properties, more than one interview was required, and in many 

instances, an interpreter was necessary. Appendix A provides copies of the completed consent 

for property access agreements. These documents are considered “Confidential Information” 

and have been flagged accordingly. Appendix G provides an electronic copy of the property 

access database in a Microsoft Access® format and photographic documentation (on a compact 

disc [CD]). 

Prior to the field sampling event and in coordination with property access activities, a qualitative 

field survey was conducted to (1) determine which homes, addressed under the RI/FS for OU 3, 

have accessible crawlspaces of 6 inches or greater; and (2) confirm the locations of residential 

properties which were not addressed during the OU 2 RI and confirm information gathered from 

the HCAD office. 

3.1.1 Residential Crawlspaces 

During the field reconnaissance, EA identified 225 OU 3 residential structures with crawlspaces 

within the Modeled Air Deposition Area and East Blower Area. Out of the 225 residential 

crawlspaces surveyed, 199 were deemed accessible (vertical ground clearance greater than or 

equal to 6 inches) and 26 were deemed inaccessible (vertical ground clearance of less than 6 

inches) (Table 2). EA visually estimated the vertical height of each crawlspace, potential 

sampling locations, and whether the crawlspace was obstructed for sampling purposes. In 

addition to the field survey, visual evidence (e.g., observance of toys, wear-paths, etc.) was 

collected indicating whether a child or small pet may be accessing a crawlspace. 

Following the field reconnaissance, EA was able to obtain consent for property access for 90 OU 

3 residences with accessible crawlspaces (Table 2). 

EA also identified residential structures with accessible crawlspaces within the Background 

Study Area (Figure 2), a neighborhood believed to be unimpacted by MDI site operations. 

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Based on air quality impact modeling of historic stack emissions performed during the 

investigation of OU 1 and OU 2 (TTEMI 2005b), an area outside the estimated limits of offsite 

contamination was selected as the Background Study Area. 

3.1.2 Residential Yards 

During the field reconnaissance, EA also identified 94 residential properties (yards) located 

within the Modeled Air Deposition Area and East Blower Area that were not sampled during the 

OU 2 RI due to property access issues (Table 3). These properties included 53 residences (i.e., 

habitable structures present on the property) and 41 vacant lots. Due to property access issues, 

EA could only gain access to sample 14 residences (i.e., habitable structures present on the 

property), including two duplexes; and 6 vacant lots (Figure 3). Property access issues included 

(1) owners and/or tenants that refused to provide consent for property access; (2) owners and/or 

tenants that were nonresponsive to repeated attempts to obtain consent; (3) owners that could not 

be contacted due to being deceased or inaccurate or outdated contact information; and (4) owners 

that could not be identified (i.e., not listed on HCAD). In most cases, these access issues were 

associated with vacant lots and abandoned properties (with unoccupied or inhabitable structures). 

3.2 QUALITATIVE DOOR-TO-DOOR SURVEYS 

Qualitative door-to-door surveys were conducted for those properties that were addressed under 

the RI for OU 3, either while attempting to obtain property access, during sampling activities, or 

following completion of sampling activities. The surveys collected information regarding 

specific exposure times for each child in a household for time spent outside in the yard and time 

spent in the crawlspace. 

Temporal aspects are important to the survey since it is likely that responses will vary from 

season to season; therefore, all questions with a temporal aspect were queried for the four 

seasons (i.e., spring, summer, fall, and winter). In addition to the questionnaire, visual evidence 

(e.g., observance of toys, wear-paths, etc.) was collected indicating whether a child or small pet 

was accessing a crawlspace. Appendix B presents a summary of the survey data collected. 

Out of the 78 residences surveyed (residences where crawlspace sampling occurred), only 41 

surveys were completed and/or returned. Based on a survey of 41 residences, the following 

survey data was collected: 

• 19 of 41 residences reported having children (total of 38 children). 

• Only 1 respondent reported that their 2 children played in the crawlspace less than 1 hour 

per day, 1 day per week. 

• All of the other respondents with children stated that their children did not play in the 

crawlspaces. 

• 13 of 41 residences reported that pets (total of 24 pets) spent time outdoors, with 7 of the 

13 residences having pets (total of 14 pets) that spent time in the crawlspace. 

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• 3 pets at 3 separate residences (1 pet per residence with pets reported to spend time in the 

crawlspace) reportedly sleep with the children an average of 1.8 days per week. 

• 11 of 41 residences reportedly grow the following quantities of produce per growing 

season for consumption: 

– Orange trees (8 - 25 pounds) 

– Peach trees (1 - 3 pounds) 

– Lemon trees (5 - 10 pounds) 

– Plum trees (10- 15 pounds) 

– Bananas (10 - 15 pounds) 

– Tomato plants (3 - 5 pounds) 

– Chile plants (0.5 - 2 pounds).

The information gathered from these door-to-door surveys was used in the determination of 

exposure parameters for the HHRA, qualitative evaluation of risk estimates in the uncertainty 

evaluation of the HHRA, and reconciliation of any investigative data gaps in preparation for 

sampling activities. 

3.3 SAMPLE COLLECTION SUMMARY 

During the RI for OU 1 and OU 2, air quality impact modeling was conducted to predict where 

(1) particulate matter from historical stack emissions would have been deposited onto the ground 

surface, and (2) soil-lead concentrations may potentially meet or exceed the EPA Region 6 

Human Health MSSL for lead associated with foundry activities (TTEMI 2005b). The model 

was based on a number of conservative input parameters regarding emission controls and lead 

concentrations in feedstock during historic foundry operations. These assumptions were 

necessitated by the limited historical information regarding site operations. The planning-level 

modeling that was performed resulted in the delineation of contours (isopleths) with different 

estimates of deposition rates corresponding to different total lead concentrations (TTEMI 

2005b): 

• At the 1.8 gram per g/m2

-year isopleth, the lead concentration is expected to be about 

1,600 mg/kg (immediate vicinity of the site [OU 1]). 

• Between the 0.8 and 1.8 g/m2

-year isopleths, the lead concentration is expected to be 

greater than 400 mg/kg, but less than 1,600 mg/kg (concentration decreases with 

increasing distance from the site). 

Beyond the 0.8 g/m2

-year isopleth, the lead concentration is expected to be less than 400 mg/kg 

(Figure 2). 

The SAP (EA 2007c) set forth a site sampling strategy to: 

Determine whether the average lead concentrations in the surface soils of residential 

yards and/or crawlspaces pose and unacceptable risk to typical/hypothetical child and 

requires remediation (e.g., removal or the elimination of the exposure pathway). 

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The study boundary for each residential yard includes exposed 2,500-square-foot (ft2) surface 

areas (e.g., sod and/or soil) within each yard; some residences may have more than one study 

boundary (e.g., front and back yard) based on the size of the exposure surface areas. Figure 4

illustrates the typical configurations for collecting residential yard surface soil samples. The 

vertical study boundary includes the soil profile from 0 to 18 inches bgs within the yard 

horizontal study boundary. Samples depth intervals include: 0 to 1 inch bgs; 0 to 6 inches bgs; 

6 to 12 inches bgs; and 12 to 18 inches bgs. Figure 5 illustrates the soil profile and sampling 

design for residential yards. 

The study boundary for each residential crawlspace includes the accessible crawlspace area 

beneath each residence that is at least 3 feet within the perimeter of the residential structure. 

Figure 4 illustrates the typical configurations for collecting crawlspace surface soil samples. 

The vertical study boundary includes the soil from 0 to 1 inch bgs within the crawlspace 

horizontal study boundary defined above. Figure 5 illustrates the soil profile and sampling 

design for crawlspaces. 

Because concentrations of lead (the primary COC for OU 3) can be accurately measured using 

XRF techniques, with a correlation in excess of 90 percent, a field XRF analyzer was used as one 

of the primary methods of analysis (EPA 1998). Samples collected offsite for metals analyses 

were analyzed with a Niton® XLp 303AW portable XRF analyzer. At 10 percent of the sample 

locations, split samples were also submitted to the EPA Region 6 Laboratory for chemical 

analysis for verification and to develop a site-specific correlation between laboratory and field 

(XRF) lead concentrations. 

A sufficient number of the samples were also processed and analyzed to develop a correlation 

between sieved and unsieved residential yard soil samples collected from the 0 to 1-inch bgs 

depth interval, and for sieved and unsieved residential crawlspace soil samples. A correlation 

was also developed for sieved residential yard soils and sieved residential crawlspace soils, 

utilizing the previously collected data from OU 2 and the data for OU 3. 

The following sections detail the 2008 RI sampling activities performed at OU 3. 

3.3.1 Residential Crawlspace Soil Sampling 

During February and March 2008, soil samples were collected from the accessible crawlspaces 

of 78 residential structures identified during reconnaissance activities (Table 2), in accordance 

with the EPA RI/FS SOW (EPA 2007b) and SAP (EA 2007c). Only properties with residential 

structures having crawlspaces that are accessible to children and pets were sampled (vertical 

clearance of greater than or equal to 6 inches) (Figure 6). At each of these 78 residences, a fivepoint composite sample was collected from a depth interval of 0 to 1 inch bgs at five discrete 

locations along the structure perimeter using a dedicated sharpshooter shovel (Figures 4 and 5). 

Each discrete location was beneath the structure (i.e., at a minimum distance of 3 feet from the 

roof drip zone toward the center of the structure), and from areas visibly accessible by children 

and/or pets. The soil was then homogenized in an aluminum pan using a disposable plastic 

scoop and transferred into a labeled resealable plastic bag for subsequent processing at the 

support zone. During sampling activities, the sampling team documented site conditions 

(including the sample locations and the presence of toys, wear-paths, paint chips, etc.) with a 

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digital camera; Appendix G provides an electronic copy of the photographs. Global Positioning 

System (GPS) coordinates were also recorded from the northeast corner of the property 

boundary. Figure 6 presents the locations where OU 3 crawlspace samples were collected. 

Using the same sampling methodology discussed above, crawlspace soil samples were also 

collected from a neighborhood believed to be unimpacted by MDI site operations (Background 

Study Area) (Figure 6). Ten background crawlspace soil samples were collected from the 

accessible crawlspaces of 10 residential structures to establish background crawlspace lead 

concentrations to differentiate between naturally-occuring or anthropogenic background (e.g., 

automobile emissions) lead concentrations and site-related deposition of lead as particulates. Per 

EPA request, EA selected five Background Study Area residences that had also been sampled 

during the OU 2 RI (residential yard soil). 

3.3.2 XRF Testing of Exterior Paint 

During February and March 2008, EA performed in situ XRF testing of the exterior painted 

surfaces for those OU 3 residential structures where crawlspace soil samples had been collected. 

The Niton® XLp 303AW portable XRF analyzer was placed directly on exterior painted surfaces 

immediately above each of the five discrete crawlspace soil sampling locations for the subject 

residential structure. The sampling team documented the field observations, including the 

material (wood, vinyl siding, aluminum siding, etc.), condition (good, poor, peeling, etc.), and 

color of the exterior walls. 

In situ XRF testing of the exterior painted surfaces was performed to evaluate whether a 

correlation existed between lead detected in crawlspace soil and any lead-based paint detected on 

the exterior walls of the corresponding structure. A strong correlation would establish that leadbased paint may be contributing some portion of the lead detected in crawlspace soil. 

3.3.3 Residential Yard Soil Sampling 

During August 2008, soil samples were collected from each 2,500-ft2

 surface area (e.g., front and 

back yards) for 14 residences (i.e., habitable structures present on the property) and 6 vacant lots 

within OU 3 (Table 3). Soil samples were collected in acetate sleeves using Geoprobe® directpush tooling. An acetate sleeve was driven at five locations within each yard (2,500-ft2

 surface 

area) to a total depth of at least 18 inches bgs to collect soil samples from 0-6, 6-12, and 12-18 

inches bgs (see Section 3.6.2; Figures 4 and 5). 

In addition to the soil collected from the three previously mentioned soil intervals, a 0 to 1-inch 

bgs soil sample was collected. The following procedure was use to collect the 0 to 1-inch bgs 

soil depth interval at each of the sampling locations: 

 

• A 4-inch by 4-inch square of sod adjacent to each corresponding 18-inch soil boring was 

carefully removed using a sharpshooter. 

• Soil was collected from the 0 to 1-inch bgs depth interval using a disposable plastic 

scoop, homogenized in an aluminum pan, and transferred into a labeled resealable plastic 

bag for subsequent processing at the support zone. 

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• Sod was replaced, using play sand, as necessary, to level the sod. 

Following sample collection, the acetate sleeves were stored for subsequent sample processing at 

the support zone. The shallow soil borings were backfilled with clean sand. During sampling 

activities, the sampling team documented site conditions, including the sample locations, with a 

digital camera. Post-sampling site conditions were also documented; Appendix G provides an 

electronic copy of the photographs. GPS coordinates were also recorded from the northeast 

corner of the property boundary. Figure 7 presents the locations where OU 3 residential yard 

soil samples were collected. 

During the previous 2003 OU 2 RI, 40 residential yard soil samples were collected from the 

Background Study Area using the same sampling methodology discussed above (Figure 6). EA 

did not collect additional residential yard soil samples from the Background Study Area during 

the 2008 OU 3 RI. 

3.3.4 Residential Drip Zone Soil Sampling 

During November 2008, EA collected soil samples from along the drip zone of four residences 

with elevated concentrations of lead in crawlspace soil, and suspected of containing lead-based 

exterior paint (based on paint chips observed and in situ XRF testing results). For the four 

subject residences, drip zone soil samples were collected adjacent to previously collected 

crawlspace soil samples. At each of these four residences, a five-point composite sample was 

collected from five discrete locations along the structure perimeter using a dedicated trowel. 

Sticks and stones were discarded; however, any observed paint chips were retained. The soil 

was then homogenized in an aluminum pan using a disposable plastic scoop and transferred into 

a labeled resealable plastic bag for subsequent sample processing. During sampling activities, 

the sample team documented the condition of soil (paint chips, etc.) and exterior paint of house 

(peeling, color of paint, etc.). Both the drip zone and corresponding crawlspace soil samples 

were submitted for a lead speciation determination. 

3.3.5 Personal Air Monitoring and Sampling 

In accordance with the HSP and SAP (EA 2007a; 2007c), personal air monitoring and sampling 

for particulates (nuisance dust) and respirable lead dust was performed during the RI field 

program to protect field personnel. Personal air sampling for total airborne particulate matter 

(PM) and lead was conducted using pre-weighed filter cassettes and a Gilian GilAir-5TM Sampler 

(per National Institute for Occupational Safety and Health [NIOSH] Method 0500). All field 

personnel performing residential yard/crawlspace soil sampling and soil sample processing/XRF 

analysis were required to participate. Total airborne PM and lead sample concentrations were 

collected during an 8-hour work schedule using hand-held air sampling equipment on or near 

personnel. Ambient air was analyzed in accordance with NIOSH Method 0500 (Particulates Not 

Otherwise Regulated, Total) and NIOSH Method 7300 (Elements by Inductively-coupled 

Plasma) to determine total dust and lead emissions, respectively. Pre-weighed filter cassettes 

were submitted to TestAmerica Laboratories in groups of up to 20 samples for batch analysis on 

a 3-day turnaround time basis. 

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PM and lead was also monitored continuously during the RI field program during residential 

yard/crawlspace soil sampling and soil sample processing/XRF analysis. 

3.3.6 Personnel Blood-Lead Testing 

All field personnel performing residential yard/crawlspace soil sampling and soil sample 

processing/XRF analysis were required to undergo baseline and follow-up blood-lead testing to 

evaluate worker protection in compliance with the Occupational Safety and Health 

Administration (OSHA) Lead Rule 29 CFR 1910.1025. 

3.4 DOCUMENTATION OF FIELD ACTIVITIES 

Field activities conducted during the RI were documented with field logbooks and photographs. 

Details of the site activities and observations were recorded in the field logbooks and field forms, 

which were maintained by each sampling team during sampling activities. All logbook entries 

and field forms were dated and signed by the individual making the entries. The logbook entries 

included the following: names of team personnel, dates and times of all entries, weather 

conditions, descriptions of all site activities, site observations, residential property sketches, site 

safety meetings, and any pertinent events or discussions. Photographs taken during the field 

activities were documented in the field logbooks and are presented in electronic format in 

Appendix G (on a CD). 

In addition to the field logbooks, sketches were completed for each of the properties investigated 

during OU 3 sampling activities. Appendix C presents a copy of the property sketches prepared 

during sampling activities. 

3.5 SAMPLE DESIGNATION 

Each sampling location was designated with a unique alphanumeric designation according to the 

following sample classifications: 

• OU 3 Crawlspace Soil Sample Designation. Soil sample designation for crawlspace 

soil samples collected within OU 3, and includes three fields that are separated by dashes; 

for example: CS-1021-S. 

– The first field, “CS,” identifies the sample type as OU 3 crawlspace soil. 

– The second field, “1021,” represents the sample identifier as illustrated on Figure 6. 

– The third field, “S,” represents whether the sample was sieved during processing, 

where: 

o S = sieved 

o U = unsieved. 

• Background Crawlspace Soil Sample Designation. Background crawlspace soil 

sample designation includes three fields that are separated by dashes; for example: 

BG-1004-U. 

– The first field, “BG,” identifies the sample as representing background crawlspace 

soil (Background Study Area). 

– The second field, “1004,” represents the sample identifier as illustrated on Figure 6. 

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– The third field, “U,” represents whether the sample was sieved during processing, 

where: 

o S = sieved 

o U = unsieved. 

• OU 3 Yard Soil Sample Designation. Soil sample designation for residential yard soil 

samples collected within OU 3, and includes five fields that are separated by dashes; for 

example: RY-1015-6-12-U. 

– The first field, “RY,” identifies the sample type as OU 3 residential yard soil. 

– The second field, “1015,” represents the sample identifier as illustrated on Figure 7. 

– The third field, “6,” represents the top of the sample interval measured in inches bgs. 

– The fourth field, “12,” represents the bottom of the sample interval measured in 

inches bgs. 

– The fifth field, “U,” represents whether the sample was sieved during processing, 

where: 

o S = sieved 

o U = unsieved. 

• OU 3 Drip Zone Soil Sample Designation. Soil sample designation for drip zone soil 

samples collected within OU 3, and includes three fields that are separated by dashes; for 

example: DL-1003-U. 

– The first field, “DL,” identifies the sample type as OU 3 drip zone (or drip line) soil. 

– The second field, “1003,” represents the sample identifier. 

– The third field, “U,” represents whether the sample was sieved during processing, 

where: 

o S = sieved 

o U = unsieved. 

• Field Duplicate Sample Designation. Field duplicate samples were identified by adding 

a “D” to the end of the sample designations described above; for example, 

CS-1021-S-D, BG-1004-U-D, and RY-1015-6-12-U-D. 

• Equipment Rinsate Blank Sample Designation. Equipment rinsate blank samples were 

identified sequentially beginning with ER-1. 

3.6 SAMPLE PROCESSING 

Sample processing, including sieving, drying (if needed), grinding (if needed), and field-portable 

XRF analysis of the residential yard and crawlspace soil samples, occurred in the sample 

processing area (support zone). The following sections discuss the procedures for processing 

and preparing samples for analysis at the sample processing area, which were performed in 

accordance with EPA technical recommendations (EPA 2000a). 

3.6.1 Residential Yard and Crawlspace Soil (0 - 1 inch bgs) 

Composited residential yard and crawlspace soil samples (including crawlspace samples 

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collected from the Background Study Area) collected from the 0 to 1-inch bgs depth interval 

were processed to yield “unsieved” samples. This process included the following steps: 

• Transfer the homogenized sample from the resealable bag to a disposable aluminum pan. 

• Drying the sample, if the moisture content of the sample was great enough to prevent the 

material from passing through a sieve. 

• Grossly sieving the sample using a No. 10 (2 millimeter [mm]) sieve to remove any large 

debris, such as sticks, rocks, etc. 

• Placing the sample into a clean resealable plastic sample bag with the sample 

identification and an “unsieved” designation. 

As indicated in SAP (EA 2007c), 25 percent of the unsieved residential yard and crawlspace soil 

samples were reserved for subsequent analysis to develop a particle size correlation between 

sieved and unsieved samples collected from the 0 to 1-inch bgs depth interval. 

A portion of each of the unsieved samples was then further processed to yield a finely sieved 

sample. This was achieved by using a No. 60 (250 micrometers [μm]) sieve to obtain the fine 

fraction (<250 μm) of the soil sample. The “sieved” samples were placed into clean resealable 

plastic bags with the sample identification and a sieved designation. The “unsieved” fraction of 

each sample was returned to its original resealable bag. 

Samples underwent additional preparation for either field XRF or fixed-laboratory analysis as 

discussed in Section 3.6.3. 

3.6.2 Residential Yard Soil (0 - 6, 6 - 12, and 12 - 18 inches bgs) 

The five discrete soil cores representing each of the 2,500-ft2

 areas (or yards) were subdivided 

into composite soil samples representative of the remaining three sample depth intervals: 0 to 6 

inches, 6 to 12 inches, and 12 to 18 inches bgs. This process included the following steps: 

• Transfer the sample aliquots for a specific depth interval from each of the five acetate 

sleeves (representing one 2,500-ft2 area or yard) into a labeled plastic resealable bag. 

• Homogenize the sample for a specific depth interval within the resealable bag. 

• Transfer the sample to a disposable aluminum pan. 

• Drying the sample, if the moisture content of the sample was great enough to prevent the 

material from passing through a sieve. 

• Grossly sieving the sample using a No. 10 (2 mm) sieve to remove any large debris such 

as sticks, rocks, etc. 

• Placing the sample into a new resealable plastic bag with the sample identification and an 

unsieved designation. 

Samples underwent additional preparation for either field XRF or fixed-laboratory analysis as 

discussed in Section 3.6.3. 

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3.6.3 Residential Yard and Crawlspace Soil Sample Preparation for Analysis 

Soil samples underwent the following additional processing prior to field-portable XRF analysis: 

• Placing approximately 5 grams of sample material into a TeflonTM sample cup 

(appropriate for XRF instrument). 

• Tapping the sample cup gently to settle the sample material. 

• Adding additional sample material, as necessary, to create a uniform surface level with 

the top of the sample cup. 

• Covering the sample cup with a pre-sized sheet of MylarTM film (X-ray window film). 

• Locking the MylarTM film onto the sample cup with the appropriate TeflonTM collar. 

• Labeling each sample with the appropriate sample designation, either directly on the 

sample cup or on a resealable bag containing the sample cup. 

Each sample underwent analyses in the field laboratory (support zone) using a field-portable 

XRF analyzer. In order to establish a correlation between the field XRF and fixed-laboratory 

data, approximately 10 percent of the soil samples were submitted to the EPA Region 6 

Laboratory for lead analyses. The same material tested using the field-portable XRF analyzer 

was submitted to the fixed laboratory for these XRF-fixed laboratory correlation samples. The 

minimum volume of soil material required by the fixed laboratory for lead analysis was placed in 

laboratory-grade 4-ounce glass, wide-mouth jar with a TeflonTM-lined cap, as specified by the 

EPA Region 6 Laboratory. 

Quality control (QC) samples were also collected and analyzed as part of this sampling effort, as 

discussed in Section 3.8. 

3.6.4 Residential Drip Zone Soil Sample Processing

Soil samples collected from residential drip zones (drip lines) underwent minimal preparation 

prior to submittal for lead speciation testing. Homogenized soil was transferred from the plastic 

bag into laboratory-grade 4-ounce glass, wide-mouth jar with a TeflonTM-lined cap. 

3.7 SAMPLING HANDLING AND CUSTODY PROCEDURES 

This section presents the sample identification, sample handling, and sample custody procedures 

followed during the RI activities. EA used EPA’s “FORMS II Lite” computer software to 

electronically track each sample identification number and all relevant field data associated with 

that number. This electronic data was imported into a Microsoft Access® database, which 

provided the framework around which analytical data were assembled. Appendix G provides an 

electronic copy of the analytical database in a Microsoft Access® format (on a CD). 

Subsequent to sample processing (Section 3.6), samples for EPA Region 6 Laboratory lead 

analysis were labeled and packaged. Completed traffic reports (chain-of-custody records) were 

generated by FORMS II Lite and signed by the appropriate sampler(s), and the EA sample 

custodian signed the form to relinquish custody to the laboratory. EA placed the signed traffic 

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reports in waterproof, resealable plastic bags inside the respective coolers, which were sealed 

with heavy strapping tape. Custody seals were placed on the two opposite sides of the coolers. 

The coolers were then transported to the EPA Region 6 Laboratory in Houston, Texas for 

chemical analysis. Each cooler was accompanied by a traffic report. 

3.8 DATA ANALYSIS AND VALIDATION 

For OU 3, 127 sieved soil samples and 122 unsieved soil samples were analyzed using a Niton® 

XLp 303AW portable XRF analyzer, while 17 sieved soil samples and 23 unsieved soil samples 

were submitted for offsite laboratory analysis. The unsieved samples were analyzed and 

compared to sieved samples to assess whether the distribution of lead in soils was related to 

particle size. The EPA Region 6 Laboratory analyzed the soil samples and associated field QC 

samples. The samples were analyzed for lead based on the historical operations at the former 

metal-casting foundry. Appendix F includes the EPA Region 6 Laboratory analytical data 

packages. 

The following soil samples (including field duplicates) were collected between February 2008 

and August 2008: 

• Background Study Area (crawlspace sample locations BG-1000 through BG-1011) 

- Fixed laboratory analysis – 2 sieved samples and 2 unsieved samples 

- Field XRF analysis – 11 sieved samples and 4 unsieved samples. 

• Offsite Residential Yards/Vacant Lots (sample locations RY-1000 through RY-1028) 

- Fixed laboratory analysis – 6 sieved and 18 unsieved samples 

- Field XRF analysis – 30 sieved and 97 unsieved samples. 

• Offsite Residential Crawlspaces (sample locations CS-1000 through CS-1085) 

- Fixed laboratory analysis – 9 sieved and 3 unsieved samples 

- Field XRF analysis – 86 sieved and 21 unsieved samples. 

As detailed in the OU 3 DESR (EA 2008b) prepared under separate cover, the analytical results 

for this sampling event met the project objectives for the quantity and quality of data required to 

support the decision-making process of this investigation. No results were rejected, yielding 100 

percent of the data usable. Data without qualifiers and data qualified as estimated are usable for 

purposes in supporting project objectives. The data were also found to be representative and 

comparable for the samples. Precision and accuracy were acceptable. 

3.8.1 XRF versus Laboratory Evaluation 

A statistical analysis was conducted to test the hypothesis that XRF could be used as a precise 

and accurate surrogate for laboratory data. This hypothesis was tested by fitting the collocated 

XRF and laboratory data to the following linear model using least squares regression: 

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XRF LAB = α + × β

where, 

α = the intercept of the regression 

β = the slope of the regression. 

The coefficient of determination (r2

) was used as a measure of the precision of the XRF data. 

The accuracy of the XRF data was examined by comparing the 95% confidence limits of the 

regression coefficients to their expected values under the null hypothesis 

H0: α = 0 , and β =1. 

The results of the regression analysis are presented in Figure E-1 and Table E-1 (Appendix E). 

The analysis shows an r2

 of 0.93 indicating a high degree of precision between collocated XRF 

and laboratory data. Both of the regression coefficients where consistent with their values under 

H0 (α = 0 and β =1) indicating that XRF provides an accurate surrogate for laboratory data. 

3.8.2 Sieved versus Unsieved Soil Fractions 

During sample preparation of soil, 25 percent of the soil samples collected from the 0 to 1-inch 

bgs depth interval, were passed through a No. 60 sieve (250 μm) sieve to obtain the fine fraction 

(<250 μm) of the soil sample. This fraction of the soil matrix was collected to represent the 

particle size (<250 μm) that tends to stick to the hands of young children while at play and 

during interaction with pets; and that are likely to be subsequently ingested due to hand-to-mouth 

behavior. 

Samples were split and analyzed for lead using the XRF, as sieved and unsieved, to assess 

whether the distribution of metals in soils was related to particle size. A comparison of 

XRF-measured lead concentrations in sieved and unsieved soil fractions was conducted for yard 

and crawlspace samples with the null hypothesis that sieved and unsieved samples would be in 

close agreement. This hypothesis was tested by fitting the collocated sieved and unsieved data to 

the following linear model using robust least trimmed squares (LTS) regression, which is 

resistant to outlier data: 

Unsieved Sieved = α + × β

where, 

α = the intercept of the regression 

β = the slope of the regression. 

The difference between sieved and unsieved XRF data was examined by comparing the 95% 

confidence limits of the regression coefficients to their expected values under the null 

hypothesis: 

H0: α = 0 , and β =1. 

The r2

 of the regression was used as a measure of the consistency of modeled relationship 

between sieved and unsieved XRF data. 

 

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The data scatter plot and LTS regression trendline for yard data is presented in Figure E-2 

(Appendix E). For yard samples, the unsieved fraction was in good agreement (r2

 = 91%, α ≈ 0, 

β ≈ 1) with the sieved fraction (Figure E-2 and Table E-2, Appendix E); and, therefore, H0 was 

not rejected. The data set, however, contained one extreme value (sample ) in which the 

unsieved fraction was approximately 30% higher than the sieved fraction. This extreme value 

may indicate that there are significant differences in the sieved and unsieved fractions in highly 

contaminated yard soil. 

The data scatter plot and LTS regression trendline for crawlspace data is presented in Figure E-3 

(Appendix E). For yard samples, the unsieved fraction was in good agreement (r2

 = 96%, α ≈ 0, 

β ≈ 1) with the sieved fraction (Figure E-3 and Table E-3, Appendix E); and, therefore H0 was 

not rejected. As with the yard data, the crawlspace data set contained one extreme value (sample 

) in which the unsieved fraction was approximately 60% higher than the sieved fraction. 

This extreme value may indicate that there are significant differences in the sieved and unsieved 

fractions in highly contaminated crawlspace soil. 

3.8.3 Sieved Crawlspace versus Sieved Yard Soil Fractions 

A statistical analysis was conducted to compare sieved crawlspace soil to sieved yard soil using 

ordinary least squares regression with the following model: 

Yard Crawlspace = α + × β

where, 

α = the intercept of the regression 

β = the slope of the regression. 

The agreement between the yard and crawlspace XRF data was examined by comparing the 95% 

confidence limits of the regression coefficients to their expected values under the null 

hypothesis: 

H0: α = 0 , and β =1. 

The r2

 was used as a measure of the precision of the agreement between yard and crawlspace 

XRF data. 

The results of the regression analysis are presented in Figure E-4 and Table E-4 (Appendix E). 

The analysis shows that for relatively low levels of contamination (< 200 mg/kg), the yard soil 

tends to contain significantly higher lead concentration than the crawlspace soil (α > 0 at the 

95% significance level). For the soils with greater levels of lead contamination, however, the 

crawlspace soil tends to be significantly more contaminated than the yard soil (β <1 at the 95% 

significance level). Although there is significant correlation between yard and crawlspace soil at 

a given residence (r2

 = 31%, p < 0.001), the magnitude of the correlation is low. Therefore, yard 

and soil data sets should be treated as distinct data populations for the purposes of risk 

assessment. 

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Because of the limited data set (only 3 residences with collocated unsieved data) for unsieved 

crawlspace soil and corresponding unsieved yard soil, a statistical analysis was not performed for 

the unsieved soil data set. 

3.8.4 Field Duplicates 

Seven pairs of field duplicates were collected and analyzed. The precision of detected results 

was calculated and evaluated against the QC criterion (< 50 relative percent difference). Only 

one set of field duplicate analytical results for lead showed inconsistencies between duplicate 

and original sample results. Inconsistencies noted with metals results may indicate heterogeneity 

of matrix and uneven distribution of contaminants in the sample matrix. 

3.8.5 Equipment Rinsate Blanks 

Fourteen equipment rinsate blanks were collected and analyzed for metals to measure the 

effectiveness of sampling equipment decontamination procedures. Lead was not detected above 

the reporting limit for the equipment rinsate blanks, unless otherwise noted. 

Lead was detected in equipment blanks collected on 27, 28, and 29 February, 1 March, and 30 

and 31 July 2008. Lead was also reported for the preparation method blank associated with the 

equipment blanks collected in July 2008. Equipment rinsate contamination is indicative of 

improper or inadequate equipment decontamination. However, the relative levels of lead 

reported for the associated field soil samples were at least 500 times greater than the levels 

reported for the equipment blanks; therefore, it is unlikely that the sampling results were 

positively biased. 

3.9 WORK PLAN DEVIATIONS 

To the extent practicable, the SAP (EA 2007c) was followed with respect to proposed sampling 

locations and procedures. Most of the deviations in the OU 3 RI field program were a function 

of difficulties with access agreements. The following deviations to the SAP occurred: 

1. During the OU 3 crawlspace soil sampling program, some duplexes were counted as 2 

residences if they met the following requirement: in the case where each half of a duplex 

was similar in size to a single-family residence, each half was treated as a single-family 

residence with its own crawlspace (on three sides); this determination was made in 

consultation with the EA risk assessor. 

2. Qualitative door-to-door surveys were only completed at 41 of the 78 of the OU 3 

residences from which crawlspace soil samples were collected. 

3. With regard to OU 3 residential yards or vacant lots that were not addressed during the 

OU 2 RI: 

– Twenty of the properties were sampled during the 2008 OU 3 RI, including 14 

residences (i.e., habitable structures present on the property) and 6 vacant lots. 

– Sixty-four owners of residences and/or vacant lots within the OU 3 Modeled Air 

Deposition Area and East Blower Area (Study Area) could not be located or were not 

listed in HCAD; therefore, these properties were not sampled. 

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– Nine owners of residences and/or vacant lots were not responsive to requests for 

access to sample the property; therefore, these properties were not sampled. 

– One property immediately adjacent to the site was addressed by ENTACT during the 

OU 1 RA; therefore, this property was not sampled. 

4. Some rental properties were sampled without the receipt of written consent from the 

tenant, due to the tenant’s concern over signing anything; these tenants gave verbal 

consent that was documented in a logbook. In these cases, the property owner (landlord) 

had granted written consent. 

5. Samples collected from all sampling intervals were analyzed with the onsite XRF, and at 

10 percent of the locations, submitted to a fixed laboratory for chemical analysis. 

Exception included: 

– Two residential yard soil samples were collected on 4 August 2008 subsequent to 

returning the XRF analyzer to the vendor; the samples were submitted to the EPA 

Region 6 Laboratory for lead analysis. 

– Drip zone soil samples were submitted to a subcontracted lead speciation laboratory. 

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4. NATURE AND EXTENT OF SOIL CONTAMINATION 

The primary source of soil contamination within the Modeled Air Deposition Area and East 

Blower Area (Study Area) is lead potentially associated with former foundry operations. 

Although soils with lead concentrations that met or exceeded the screening level were identified 

throughout the Modeled Air Deposition Area and East Blower Area, microscopic evaluation and 

statistical comparisons of the OU 1 and OU 2 RI data indicate that the MDI site is not the sole 

source of elevated lead concentrations in Modeled Air Deposition Area and East Blower Area 

soils (see Section 4.2). 

OU 3 RI activities involved the investigation of surface soils in the neighborhoods surrounding 

the MDI site, with the area of investigation delineated using air quality impact modeling that was 

performed during implementation of the OU 2 RI (TTEMI 2005b) (i.e., the Modeled Air 

Deposition Area and East Blower Area). Over the course of the OU 3 RI, 270 soil samples, 

including 151 residential yard soil samples (representing 22 residential properties) and 119 

residential crawlspace soil samples (representing 78 residential properties), were collected and 

analyzed for lead. In addition to the soil samples collected for OU 3 characterization purposes, 

19 background crawlspace soil samples were also collected for comparative purposes from 10 

residences located in the Background Study Area (Figure 6). Appendix D provides table 

summaries of the results of all chemical analyses performed as part of this investigation. 

Appendix E presents the fixed laboratory analytical data packages. Appendix G contains an 

electronic copy of the project analytical database on a CD (Microsoft Access® format). 

4.1 SOIL CONTAMINATION 

During the OU 3 RI, surface soil samples collected from within the Modeled Air Deposition 

Area and East Blower Area were analyzed for lead using the Niton® XLp 303AW portable XRF 

analyzer. Split samples were collected at 10 percent of the sample locations and submitted to a 

fixed laboratory for analysis. By submitting split samples to a fixed laboratory, a correlation 

could be developed between the two analytical methodologies. 

 

As discussed in Section 3.8 and the DESR (EA 2008b), lead showed a strong correlation 

(r2

 = 0.93 > 0.80) between XRF and fixed laboratory data. Lead results for residential yard soil 

were compared with three surface soil screening criteria in a hierarchical approach: (1) EPA 

Regional Screening Levels (RSL) for the residential land use scenario (EPA 2008), which 

replaced the EPA Region 6 MSSLs (EPA 2007c) as screening criteria; (2) the MDI median 

background lead concentrations; and (3) the Texas-specific median concentrations. For the MDI 

background lead concentrations, (1) depth-specific median concentrations established during the 

2003 RI were used for residential yard soil; and (2) a median concentration was calculated for 

residential crawlspace soil based on Background Study Area samples collected during the 2008 

RI. The EPA RSL was the highest surface soil screening criteria. Table 4 summarizes the 

screening criteria used for the site. 

 

The following sections address the distribution of lead in surface soils in the OU 3 residential 

crawlspaces and yards. 

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4.1.1 Residential Crawlspace Soil 

Crawlspace soils were evaluated to a depth of 1 inch bgs. Figure 6 presents the distribution of 

lead in the OU 3 residential crawlspaces that were sampled within the Modeled Air Deposition 

Area and East Blower Area (Study Area). 

Detected lead concentrations ranged from 15.03 to 3,204 mg/kg. There is no EPA RSL for lead 

in residential crawlspace soil; however, an action level was evaluated in the HHRA Report (EA 

2009). Section 5 presents a summary of the HHRA findings. Appendix D presents a tabulated 

summary of all the analytical data. 

4.1.2 Residential Yard Soil (0 – 18 inches bgs) 

Under a residential land use scenario, surface soils (residential yards) are those that extend to 18 

inches bgs. Figure 7 presents the highest reported concentration of lead (XRF and fixed 

laboratory) in residential yard soils for each of the following four depth intervals: 

• 0 to 1 inch bgs 

• 0 to 6 inches bgs 

• 6 to 12 inches bgs 

• 12 to 18 inches bgs. 

Detected concentrations of lead in OU 3 residential yard soil samples ranged from 14.2 to 1,190 

mg/kg. Soil samples collected from 6 of the 20 residential properties contained lead 

concentrations equal to or greater than the EPA residential RSL of 400 mg/kg (Table 5). 

Appendix D presents a tabulated summary of all the analytical data. 

Lead was only detected at concentrations equal to or greater than the EPA residential RSL of 400 

mg/kg in the 0 to 1-inch and 0 to 6-inch bgs soil depth intervals. Mean concentration of lead was 

higher in the 0 to 1-inch bgs interval (901.5 mg/kg) than in the 0 to 6-inch bgs soil depth interval 

(764.6 mg/kg). Lead concentrations for soil samples collected from the 6- to 12-inch and 12- to 

18-inch bgs depth intervals were all below the EPA residential RSL of 400 mg/kg. 

The maximum lead concentrations detected for each of the four depth intervals are as follows: 

• 1,190 mg/kg for the 0 to 1-inch bgs depth interval 

• 986.06 mg/kg for the 0 to 6-inch bgs depth interval 

• 289.02 mg/kg for the 6- to 12-inch bgs depth interval 

• 196.27 mg/kg for the 12- to 18-inch bgs depth interval. 

4.2 SOURCE EVALUATION 

In addition to the standard evaluation of the nature and extent of contamination, additional 

analyses were performed in order to assess the potential source of lead contamination. 

Following completion of the 2003 RI field program, the EPA National Exposure Research 

Laboratory in Las Vegas, Nevada (NERL-LV) evaluated the data to make a source determination 

(TTEMI 2003; 2005b). In addition, during the 2008 RI field program, EA performed (1) in situ

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XRF testing of the exterior painted surfaces of OU 3 residential structures where crawlspace soil 

samples had been collected; and (2) subcontracted lead speciation testing of drip zone soil 

samples and corresponding crawlspace soil samples. The following sections also present 

background information about the MDI site and vicinity. 

4.2.1 Site Geology 

The MDI site is directly underlain by the Beaumont Formation of the Pleistocene Epoch, which 

consists of former barrier island and beach deposits. The Beaumont Formation is made up of 

clay, silt, and sand formed from stream channel, point-bar, natural levee, back swamp, coastal 

marsh, and mud flat deposits. There is nothing in the geological record that could account for 

the elevated lead concentrations found in residential soils. 

4.2.2 Historic Land Use 

The MDI site was originally the Houston Brick Works brickyard. In 1926, the TESCO began 

operations as a metal casting foundry initially occupying the former Houston Brick Works 

facility and later expanding into a larger area. During the mid-1980s, the southern portion of the 

site was used by Can-Am Resource Group for a catalyst recycling operation. TESCO ceased 

operations in February 1991, and MDI foreclosed on the property. MDI reopened as the San 

Jacinto Foundry in 1991, but filed for Chapter 7 Bankruptcy in 1992. The onsite facilities were 

demolished as a salvage operation under order of the U.S. district bankruptcy court in the mid 

1990’s. 

4.2.3 Potential Sources of Lead 

There are several potential sources of lead in the vicinity of the site. The primary anthropogenic 

source of soil contamination is lead potentially associated with former foundry operations. The 

MDI site is also located in close proximity to I-10. Elevated lead concentrations may be related 

to industrial operation from sources such as paint, solder, etc. as well as automobile exhaust. 

4.2.4 EPA NERL Source Evaluation (OU 1 and OU 2) 

The EPA NERL-LV evaluated the data using statistical analysis, microscopy analysis, and an 

evaluation of the ratio of the metals in samples (TTEMI 2003, 2005b). 

4.2.4.1 Statistical Analysis 

Using the software SYSTATTM Version 10.2, EPA NERL-LV prepared a number of scatter plots 

that compared the fixed laboratory results with the field XRF results. Based on an exploratory 

analysis of the 2003 RI data for the 0 to 6-inch soil depth interval (OU 1 and OU 2), EPA made 

the following conclusions: 

• OU 1 is not the source of any widespread contamination over the sampled offsite area 

(Modeled Air Deposition Area and East Blower Area). 

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• OU 1 is probably the source of some relatively localized contamination in the areas 

adjacent to the site boundary. For the most part, the concentrations of metals in the 

offsite area (Modeled Air Deposition Area and East Blower Area [Study Area]) are 

virtually identical to those in the Background Study Area, and both are very different 

from the onsite concentrations (OU 1). 

• OU 1 has a distinctive “fingerprint” characterized by relatively high levels of chromium, 

iron, manganese, molybdenum, nickel, and zirconium; and low levels of aluminum, 

barium, lead, mercury, and zinc. 

• Lead contamination in the Modeled Air Deposition Area, East Blower Area, and 

Background Study Area soil samples is characterized by a strong correlation with zinc. 

One possible source is paint with a combination of lead carbonate and zinc oxide 

pigments. 

Onsite (OU 1) samples contained a few elevated lead values, but they were not characteristic of 

the site in general, which is low in lead. The relatively few high lead values were probably 

outliers that might be expected in any industrial operation from sources such as paint, solder, etc. 

These isolated high values do not appear to contain a large enough mass of lead to be a likely 

source for the relatively high and widespread lead levels characteristic of the Modeled Air 

Deposition Area, East Blower Area, and Background Study Area. 

Additionally, a statistical evaluation of the OU 2 crawlspace soil data concluded that no 

significant correlation exists between the lead concentrations in crawlspace soil and the lead 

concentrations in the yard soil. That is, the lead concentration in the yard samples is not a good 

predictor of the lead concentration in crawlspaces. This indicates that the sources of lead in 

crawlspace soil may not be attributable to the site and may be due to other anthropogenic 

sources, such as lead plumbing solder, lead-based paint, or automobile exhaust. 

4.2.4.2 Microscopy Analysis of Soils 

In addition to a scatter plot analysis, EPA NERL-LV directed the assessment of bag house and 

on- (OU 1) and offsite (Modeled Air Deposition Area and East Blower Area) soil samples using 

scanning electron microscopy (SEM) analysis. A definitive correlation could not be established 

between the lead contamination found at the MDI site and the offsite (Modeled Air Deposition 

Area and East Blower Area) lead contamination based on analysis of SEM images and 

evaluation of samples for “marker” compounds. Lead and iron compounds found in the onsite 

bag house sample (Wulfenite and lead oxide sulfate) were not found in soil samples collected 

from onsite areas (OU 1), offsite residences (Modeled Air Deposition Area and East Blower 

Area), or the Background Study Area. In addition, no clearly definable “marker” compounds 

could be established between onsite (OU 1) soil samples and soil samples collected from offsite 

residences (Modeled Air Deposition Area and East Blower Area) and the Background Study 

Area. 

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4.2.4.3 Ratio of Metals in Soils 

During the 2003 RI, five samples of bag house waste were collected on site and analyzed for 

total metals and toxicity characteristic leaching procedure metals. These samples were used as a 

standard to compare with offsite results. The premise of this assessment was that in order for 

metal concentrations in offsite soils to be fully attributable to onsite activities, the ratios of the 

metals should be similar. 

Lead, chromium, and molybdenum were selected as heavy metals that are likely to be associated 

with foundry wastes. The ratios of these three metals in soils were determined by setting the 

molybdenum concentration equal to one and calculating relative ratios of lead and chromium. 

The ratio of these metals in bag house and onsite (OU 1) samples were very similar, suggesting 

that the metal concentrations onsite are attributable to site releases. The ratios for these metals in 

samples collected from the Modeled Air Deposition Area and East Blower Area (offsite, 

including crawlspaces) are significantly different, suggesting that there are other sources of lead 

contributing to the concentrations measured in soils. The ratio of lead and chromium in bag 

house and onsite (OU 1) samples is 1:1; whereas, the lead to chromium ratio in offsite (Modeled 

Air Deposition Area and East Blower Area) soil samples is 241:15, or approximately 16:1, 

indicating that other non-site-related sources of lead are contributing to the much higher 

concentrations measured in offsite soils. Two likely sources are tail pipe emissions from 

automobiles during the period when leaded gasoline was in use (pre mid-1970s), as well as leadbased paint from residences. Lead-based paint is a well-known source of lead in soils, and is a 

likely contributor, given the fact that houses in the area are reported to have undergone leadbased paint abatement and removal activities. 

4.2.5 OU 3 Source Evaluation 

The following sections discuss the results of in situ XRF testing of the exterior painted surfaces 

of OU 3 residential structures where crawlspace soil samples had been collected, and 

subcontracted lead speciation testing of drip zone soil samples and corresponding crawlspace soil 

samples. 

4.2.5.1 In Situ XRF Testing of Exterior Paint 

In situ XRF testing of the exterior painted surfaces was performed to evaluate whether a 

correlation existed between lead detected in crawlspace soil and any lead-based paint detected on 

the exterior walls of the corresponding structure. In situ XRF testing of the exterior painted 

surfaces of OU 3 residential structures where crawlspace soil samples had been collected 

detected lead ranging from less than 0.002 to 4.36 milligrams per square centimeter (mg/cm2

). 

The Department of Housing and Urban Development (HUD)/EPA standard for lead-based paint 

is 1 mg/cm2

, as defined in Title X of the 1992 Housing and Community Development Act. Lead 

in the exterior paint exceeded the HUD/EPA standard for lead-based paint in 12 of the 76 OU 3 

residential structures where crawlspace soil samples were collected. Of the 12 lead-based paint 

exceedances, only five corresponding crawlspace soil samples had concentrations of lead that 

exceeded the residential RSL of 400 mg/kg. Table 6 compares the 12 HUD/EPA exceedances 

with their corresponding crawlspace soil-lead concentrations. 

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Linear regression analysis of the data set indicates that a poor correlation exists between average 

lead concentrations measured in residential exterior paint and corresponding soil-lead 

concentrations for OU 3 crawlspaces and the Background Study Area (i.e., the lead concentration 

detected in the exterior walls of a residential structure not a good predictor of the lead 

concentration in crawlspace soil). 

Figure E-5 (Appendix E) illustrates the correlation between in situ paint samples and 

sieved/unsieved crawlspace soil samples gathered from residential structures located in the 

Background Study Area. The r2

 values of 0.2057 (sieved) and 0.0000004 (unsieved) indicate 

that a very poor correlation exists between the lead concentrations detected in the exterior paint 

and crawlspace soil for a particular residential structure located within the Background Study 

Area. 

Figure E-6 (Appendix E) illustrates the correlation between in situ paint samples and sieved/ 

unsieved crawlspace soil samples gathered from residential structures located within OU 3. The 

r

2

 values of 0.00000003 (sieved) and 0.0433 (unsieved) indicate that a very poor correlation 

exists between the lead concentrations detected in the exterior paint and crawlspace soil for a 

particular residential structure located within OU 3. 

Therefore, lead-based paint is apparently not contributing a significant portion of the lead 

detected in crawlspace soil samples. Subsequent lead speciation testing corroborated this 

evaluation, as discussed below (Section 4.2.2.2). 

Appendix D presents a tabulated summary of all the analytical data. 

4.2.5.2 Lead Speciation Evaluation 

A study was performed to determine whether lead-based paint is a significant contributing factor 

to the crawlspace soil lead content. Representative samples submitted to the laboratory, FAI 

Materials Testing Laboratory (FAI), Marietta Georgia, for evaluation included four samples of 

soil mixed with paint chips from the residential drip line and four samples of soil collected in the 

residential crawlspace. The results of the lead speciation testing performed by FAI are presented 

in Appendix F. 

The methodologies used by FAI for sample preparation, data collection, and testing are described 

below. Prior to examination, weighed portions of the samples were sorted under an optical 

microscope to identify and remove paint fragments from the soil mass. The weight fractions of 

the soil and paint fragments for each sample were recorded (see Table 1 of FAI report in 

Appendix F) to yield percent paint in soil. 

The sorted fractions of paint chips and also soil were examined by scanning electron microscope 

with energy dispersive x-ray spectroscopy (SEM-EDXS) as well as elemental mapping (see 

Figures 1 to 6 in FAI report in Appendix F). To validate the SEM-EDXS test results, paint 

standards were initially analyzed to confirm the sensitivity and accuracy of the method (see 

Table 2 of FAI report in Appendix F). The elemental analyses by SEM-EDXS of the soil and 

paint fractions are presented in Tables 3 and 4 of the FAI report in Appendix F. The 

concentrations of lead in the paint chip samples are much higher than the associated soil fraction. 

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The largest paint chips found in the paint chips samples were separately analyzed by SEMEDXS; these results showed much lower concentrations of lead (see Figures 7 through 22 and 

Table 5 of FAI report in Appendix F). These varying results may show that there are different 

layers of paint present and only some of these layers are formed by lead-based paint. 

The sorted soil and paint fractions were also analyzed by a Niton portable XRF unit. The first 

round of testing was inconclusive due to background issues (see Table 6 of FAI report in 

Appendix F). The samples were retested on a different background (see Table 7 of FAI report in 

Appendix F). The percent contribution of lead content in each fraction was determined by 

incorporating the weight percent of each fraction (soil and paint) from Table 1. These results 

show that the source of the majority of the lead present in the original samples is found in the 

soil fraction rather than the paint fraction. 

The following statements are based upon the findings of the tests performed by FAI: 

• There were leaded as well as unleaded paint chips found in both the crawlspace and drip 

line samples (see Table 7 of FAI report in Appendix F). 

 

• The lead found in the both soil types (crawlspace and drip line) is significant compared to 

the lead found in the paint fragments (see Table 7 of FAI report in Appendix F). 

• There is lead from sources other than the lead-based paint in both sets of samples 

(crawlspace and drip line) (see Table 7 of FAI report in Appendix F). 

• The contribution of lead from lead-based paint is smaller in the crawlspace samples than 

in the drip line samples (see Table 7 of FAI report in Appendix F). 

• The gravimetric comparison of the mass of paint chips to soil shows there are more paint 

chips by weight in the drip line samples than the crawlspace samples (see Table 1 of FAI 

report in Appendix F). 

The conclusions of the report show that there are other sources of lead in the crawlspace soil 

other than lead-based paint. There are several sources of uncertainty in the conclusions formed 

based upon the testing results. The reported results are reflective of the samples submitted for 

evaluation and there is uncertainty extrapolating the results from these samples and the 

individual paint chips to areas of the site represented by the samples. 

4.3 HEALTH AND SAFETY 

In compliance with OSHA Lead Rule 29 CFR 1910.1025, as well as the HSP and SAP (EA 

2007a; 2007c), EA implemented an air sampling and medical monitoring program to ensure 

worker protection against lead exposure during the OU 3 field program. The following sections 

summarize the results of the health and safety program. 

4.3.1 Air 

As discussed in Section 3.3.5, ambient air samples collected from EA field personnel during 

residential yard/crawlspace soil sampling and soil sample processing/XRF analysis was analyzed 

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in accordance with NIOSH Method 0500 (Particulates Not Otherwise Regulated, Total) and 

NIOSH Method 7300 (Elements by Inductively-coupled Plasma) to determine total dust and lead 

emissions, respectively. 

Following receipt of sample results for the first week of activity, data evaluation indicated that 

airborne lead was well below the OSHA Permissible Exposure Limit, and personal air sampling 

activities were discontinued. 

4.3.2 Blood Lead 

As discussed in Section 3.3.6, all field personnel performing residential yard/crawlspace soil 

sampling and soil sample processing/XRF analysis were required to undergo baseline and 

follow-up blood-lead testing to evaluate worker protection in compliance with OSHA Lead Rule 

29 CFR 1910.1025. Baseline and follow-up blood-lead testing did not detect lead in any of the 

field personnel above the OSHA Lead Rule action level of 40 micrograms per deciliter (μg/dL).

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5. HUMAN HEALTH RISK ASSESSMENT 

EA prepared an HHRA Report (EA 2009) that characterizes and quantifies the current and 

potential human health effects associated with exposure to lead within OU 3. Site-specific data 

was evaluated using the IEUBK Model for Lead in Children (EPA 1994, 2005b, 2007a) to 

predict a soil lead level that is protective of children and adults. 

EA performed a deterministic exposure assessment to identify the magnitude of actual or 

potential human exposures, the frequency and duration of these exposures, and the routes by 

which receptors are exposed. Figure 8 illustrates the primary sources, release mechanisms, and 

exposure pathways that were evaluated during the risk assessment. The exposure assessment 

included an evaluation of the likelihood of such exposures occurring and provided the basis for 

the development of acceptable exposure levels. In developing the exposure assessment, EA 

developed reasonable maximum estimates of exposure for both current and potential future land 

use conditions at the site. EA utilized the IEUBK Model for assessing lead exposure. 

EA performed a probabilistic exposure assessment to further characterize uncertainty associated 

with exposure time and exposure point concentration assumptions. The probabilistic HHRA also 

estimated a site-specific clean-up goal for lead in crawlspaces. The probabilistic assessment 

incorporated the results of qualitative door-to-door surveys to determine the exposure frequency 

of children accessing a crawlspace mindful of the season. 

EA identified critical assumptions (e.g., background concentrations and conditions) and 

uncertainties in the HHRA. A “Monte Carlo” evaluation was used to address uncertainty in the 

exposure assumptions. 

A deterministic risk analysis is one in which a discrete value is represented in an equation 

yielding a discrete value (for example X + 1 = Y where X = 2, such that Y = 3). A Monte Carlo 

(probabilistic) risk assessment, however, involves the process of picking random values that 

follow a statistical distribution (such as log normal, normal, or triangular) for a large number of 

times (such as 10,000 random picks), and calculating an objective from these picks. The 

objectives in this case are determining the exposure point concentration (EPC) and crawlspace 

clean-up level statistical distributions. The individual distributions, in this case, are based 

directly on soil samples collected from OU 3 residential yards and crawlspaces. The 

resulting objective (exposure concentration to the yard and crawlspaces combined) is then 

calculated from these random picks. Each calculation of the objective includes each random 

pick and yields a corresponding data point for the objective. Thus, for each randomly chosen 

concentration from the yard and crawlspace databases, a resulting objective concentration 

representative of actual expected exposure to both yard and crawlspace is generated. The large 

number of iterative selections from the yard and crawlspace distributions thus generates a data 

set for the objective from which a corresponding distribution can then be identified. For risk 

management purposes, the objective data set and distribution (concentration representative of 

yard and crawlspace exposure) can then be used to determine risk management objectives 

regarding potential clean-up. This differs from the standard deterministic method, which is 

based upon the discrete analysis of one concentration representative of the site. 

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The HHRA evaluated the prospective “baseline” conditions after the TNRCC (1999) and EPA 

(2003, 2005, and 2006) removal actions. The focus of the OU 3 evaluation included residential 

crawlspaces and those residential yards not addressed under OU 2 that are located within the 

Modeled Air Deposition Area and East Blower Area (Study Area). The deterministic and 

probabilistic risk evaluations for residential yards and crawlspaces are presented in Sections 5.1 

and 5.2, respectively. 

5.1 DETERMINISTIC RISK ASSESSMENT 

A deterministic evaluation was conducted to evaluate exposure to lead in residential yard and 

crawlspace soils. In order to evaluate a range of exposure scenarios, five deterministic 

evaluations were conducted as follows: 

• Deterministic residential yard soil with no crawlspace exposure 

1. Deterministic residential yard soil with hypothetical crawlspace exposure using a TWA 

approach for the following scenarios: 

a. Evaluation assuming existing conditions 

b. Evaluation assuming that 2009 removal action for OU 3 yards has been completed 

• Deterministic neighborhood risk evaluation with and without hypothetical crawlspace 

exposure using a TWA approach (pre- and post-2009 scheduled removal action) 

• Deterministic residential yard soil for the single residence ( ) where the survey 

indicated children were playing in the crawlspace 

• Deterministic sensitivity evaluation to evaluate preliminary remediation goals (PRGs) for 

crawlspaces. 

The risk characterization results of these evaluations are contained in the following sections. 

Appendix B of the HHRA Report (EA 2009) presents the probability graphs for those 

samples/locations evaluated using the IEUBK Model and the following model output: 

• Geometric mean predicted blood-lead level 

• Percent of children predicted to be above the blood-lead threshold of 10 μg/dL. 

The lead data, geometric mean blood-lead levels, and percentage of exposed children estimated 

to have a blood-lead level greater than 10 μg/dL are summarized in the tables referenced in the 

following sections. Numerical results of the modeling were rounded to one decimal place in this 

summary to parallel the precision of the soil lead concentration data. 

The EPA OU 2 removal action level of 463 mg/kg was used in a weight-of-evidence approach in 

conjunction with the output from the IEUBK Model to identify residences that may be subject to 

a remedial decision (based on EPA’s discretion). 

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5.1.1 Deterministic Residential Yard Soil with No Crawlspace Exposure 

To evaluate exposure to lead in residential yard soil in the absence of crawlspace exposure, the 

residential yard EPC was modeled using the IEUBK Model. IEUBK modeling results indicate 

that there are seven residential yards where the percentage of exposed children with an estimated 

blood-lead level exceeding the lead level of concern of 10 μg/dL was greater than the EPA 

Office of Solid Waste and Emergency Response (OSWER)-recommended threshold of 5 percent 

(see Table 7A). Of these, six residences ( , and 

) also exceeded the EPA removal action level of 463 mg/kg and the estimated 

percentage of children predicted to have a blood-lead level greater than 10 μg/dL was greater 

than 10 percent. When modeled concentrations exceed the EPA removal action level of 463 

mg/kg and the EPA OSWER-recommended threshold of 5 percent is exceeded, then the 

residential yard is subject to a risk management decision (see Figure 9). Given that residential 

yards exceeding the EPA removal action level of 463 mg/kg were subject to removal action for 

OU 2, the same protocol is recommended for OU 3. 

Residential areas where the estimated percentage of children predicted to have a blood-lead level 

greater than 10 μg/dL exceeded 5 percent, the yard concentration was replaced with the 

background lead concentration for the Study Area (150 mg/kg) to evaluate a post remediation 

scenario (see Table 7B). Using the background lead concentration was considered protective 

since the clean fill utilized in remediation of yards had considerably lower lead concentrations of 

approximately 5 mg/kg. The results of this evaluation demonstrate that remediation of yards 

with lead concentrations that exceed the EPA removal action level of 463 mg/kg would reduce 

the estimated percentage of children predicted to have a blood-lead level greater than 10 μg/dL 

to less than 5 percent for these six residences. 

Risk Management Decision: At EPA’s discretion, these six residential yards , 

) are scheduled for removal action to 

mitigate the potential deleterious effects associated with exposure to lead in soil. 

The final OU 3 exceedance of the EPA OSWER-recommended threshold of 5 percent occurred 

in the back yard at (sample RY-1018), which had a modeled lead concentration of 

416 mg/kg. This concentration is below the EPA removal action level of 463 mg/kg. The 

estimated geometric mean blood-lead concentration was 4.7 μg/dL and the estimated percentage 

of children predicted to have a blood-lead level greater than 10 μg/dL was 5.6 percent. Although 

this percentage slightly exceeds the EPA OSWER-recommended threshold of 5 percent, the front 

yard sample collected at (sample RY-1017) had a concentration of 209 mg/kg. 

Therefore, children from this household are likely to be exposed to an average of these two 

concentrations (416 mg/kg and 209 mg/kg), or approximately 313 mg/kg, which is below the 

EPA RSL (EPA 2008) and EPA removal action level of 463 mg/kg. 

Risk Management Decision: At EPA’s discretion, this OU 3 residential yard may 

not be recommended for remedial action. 

There was a single residential sample (i.e., sample RS0114 from ) that was collected 

during the OU 2 evaluation, but was not evaluated in previous reports. The concentration of lead 

was 417 mg/kg, which is below the EPA removal action level of 463 mg/kg. A geometric mean 

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blood-lead concentration was estimated at 4.8 μg/dL and the estimated percentage of children 

predicted to have a blood-lead level greater than 10 μg/dL was 5.7 percent. Although this 

percentage exceeds the EPA OSWER-recommended threshold of 5 percent, the soil removal 

action level of 463 mg/kg is considered protective of human health due to the uncertainties 

associated with the conservative exposure assumptions used in the HHRA (see Section 5.3). 

This sample is not presented in Table 7A. 

Risk Management Decision: At EPA’s discretion, this OU 2 residential yard ( ) may 

not be recommended for remedial action. 

5.1.2 Deterministic Residential Yard Soil with Hypothetical Crawlspace Exposure Using a 

Time-Weighted Average Approach 

To evaluate exposure to lead in residential yard soil with potential crawlspace soil exposure, the 

highest residential yard composite soil sample (from the 0 to 1-inch and 0 to 6-inch depth 

intervals) and crawlspace composite soil sample were modeled using the IEUBK Model in a 

TWA approach. The results of the residential yard and crawlspace lead evaluation are presented 

on Table 8A. Residential areas where the estimated percentage of children predicted to have a 

blood-lead level greater than 10 μg/dL exceeded 5 percent, the yard concentration was replaced 

with the background lead concentration for the Study Area (150 mg/kg) to evaluate a post 

remediation scenario (see Table 8B). Using the background lead concentration was considered 

protective since the clean fill utilized in remediation of yards had lead concentrations of 

approximately 5 mg/kg. 

Three residences without crawlspace samples (i.e., ) exceeded 

the EPA OSWER-recommended threshold of 5 percent are not discussed further in this section 

because they were evaluated in the previous section. 

Four additional residences with crawlspaces ( ) were 

also discussed in the previous section because their residential yards exceeded the EPA OSWERrecommended threshold of 5 percent. Nevertheless, they were evaluated again with the inclusion 

of crawlspace samples. These four residences are part of a larger group of 26 residences where 

the estimated blood-lead level exceeding the lead level of concern (10 μg/dL) was greater than 

the EPA OSWER-recommended threshold of 5 percent and the yard composite sample 

concentration exceeded the EPA removal action level of 463 mg/kg (see Table 8A). The 

estimated percentage of children predicted to have a blood-lead level greater than 10 μg/dL was 

near or greater than 10 percent when using the TWA EPC. When modeled concentrations 

exceed the EPA removal action level of 463 mg/kg and the EPA OSWER-recommended 

threshold of 5 percent is exceeded, then the residential yard is subject to a risk management 

decision (see Figure 9). Given that residential yards exceeding the EPA removal action level of 

463 mg/kg were subject to removal action for OU 2, the same protocol is recommended for 

OU 3. 

Residences where the estimated percentage of children predicted to have a blood-lead level 

greater than 10 μg/dL exceeded 5 percent and the yard concentrations were greater than the EPA 

removal action level of 463 mg/kg, the yard concentration was replaced with the background 

lead concentration for the Study Area (150 mg/kg) to evaluate a post remediation scenario (see 

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Table 8B). Using the background lead concentration was considered protective since the clean 

fill utilized in remediation of yards had lead concentrations of approximately 5 mg/kg. The 

results of this evaluation demonstrate that remediation of yards with lead concentrations that 

exceed the EPA removal action level of 463 mg/kg would reduce the estimated percentage of 

children predicted to have a blood-lead level greater than 10 μg/dL to less than 5 percent for all 

but nine residences. 

• Residence exceeded the EPA OSWER-recommended threshold of 5 percent, but 

was not discussed further in this section because it was evaluated in the previous section. 

• Residence exceeded the EPA OSWER-recommended threshold of 5 percent, 

but the crawlspace exposure, which is the contributing factor, was based on a 

conservative estimate of exposure (e.g., two days a week exposure to crawlspace soil) 

that is not likely to occur based on the door-to-door surveys. 

• The final five residences (i.e., , and ) are 

evaluated below. 

There were five residences (i.e., ) with 

crawlspace samples that exceeded the EPA OSWER-recommended threshold of 5 percent but 

had yard concentrations less than the EPA removal action level of 463 mg/kg. For (RS0114), (RS-0315), (RS-0091), and (RS-0248), the estimated 

geometric mean blood-lead concentration was 4.8 μg/dL and the estimated percentage of 

children predicted to have a blood-lead level greater than 10 μg/dL ranged from 5.7 to 6.1 

percent. Although this percentage slightly exceeds the EPA OSWER-recommended threshold of 

5 percent, the yard sample concentrations were less than the EPA removal action level of 463 

mg/kg. Two residences (i.e., [RS-0312 and RS-0314] and [RS-0149]) had an 

estimated geometric mean blood-lead concentration range from 5.1 to 5.4 μg/dL and the 

estimated percentage of children predicted to have a blood-lead level greater than 10 μg/dL 

range from 7.5 to 9.3 percent. However, the yard sample concentrations were less than the EPA 

removal action level of 463 mg/kg. It should be noted that the crawlspace exposure, which is the 

contributing factor, was based on a conservative estimate of exposure (i.e., 2 days a week 

exposure to crawlspace soil) that is not likely to occur based on the door-to-door surveys. As 

with the other samples with modeled concentrations exceeding the EPA OSWER-recommended 

threshold of 5 percent, these residential yards are subject to a risk management decision (see 

Figure 9). 

Risk Management Decision: At EPA’s discretion, these residential yards with and without 

crawlspaces may be considered for remedial action to mitigate the potential deleterious effects 

associated with exposure to lead in soil. 

5.1.3 Deterministic Neighborhood Risk Evaluation with and without Hypothetical 

Crawlspace Exposure Using a Time-Weighted Average Approach 

The TWA approach for evaluating exposure to residential yard soil and hypothetical exposure to 

crawlspace soil in a “neighborhood risk” approach utilizes the results from the prior evaluation. 

Neighborhood risk estimates apply to children who are exposed to residential yard and 

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crawlspace soil in the neighborhood. It is assumed that the child spends equal time in all 

residential yards in the neighborhood. It is also based on a conservative estimate of exposure 

(i.e., 2 days a week exposure to crawlspace soil) that is not likely to occur based on the door-todoor surveys. Nevertheless, the neighborhood risk estimates are useful in evaluating the 

potential risk to children in the community both before and after remediation has occurred. To 

this end, the neighborhood risk estimates provided below for the residential yard and crawlspace 

lead neighborhood risk evaluation are presented on Table 8A for the pre-remediation scenario 

and Table 8B for the post-remediation scenario. 

The average percentage of exposed children with a predicted blood-lead level greater than 10 

μg/dL for OU 3 residences with and without crawlspaces (see Table 8A) is 8.7 percent, which is 

greater than the EPA OSWER-recommended threshold of 5 percent. Also, the average 

percentage of exposed children with a predicted blood-lead level greater than 10 μg/dL for only 

those residences with crawlspaces (see Table 8A) is 10 percent, which is greater than the EPA 

OSWER-recommended threshold of 5 percent. 

When the neighborhood risk evaluation demonstrates that the EPA OSWER-recommended 

threshold of 5 percent is exceeded, then residential yards within the neighborhood may be 

subject to a risk management decision. 

Residences where the estimated percentage of children predicted to have a blood-lead level 

greater than 10 μg/dL exceeded 5 percent and the yard concentrations were greater than the EPA 

removal action level of 463 mg/kg, the yard concentration was replaced with the background 

lead concentration for the Study Area (150 mg/kg) to evaluate a post-remediation scenario (see 

Table 8B). Using the background lead concentration was considered protective since the clean 

fill utilized in remediation of yards had lead concentrations of approximately 5 mg/kg. The 

average percentage of exposed children with a predicted blood-lead level greater than 10 μg/dL 

for OU 3 residences with and without crawlspaces in a post-remediation scenario (see Table 8B) 

is 1.6 percent, which is less than the EPA OSWER-recommended threshold of 5 percent. Also, 

the average percentage of exposed children with a predicted blood-lead level greater than 10 

μg/dL for only those residences with crawlspaces in a post-remediation scenario (see Table 8B) 

is 1.8 percent, which is less than the EPA OSWER-recommended threshold of 5 percent. 

Although there are a few yards with predictions greater than the EPA OSWER-recommended 

threshold of 5 percent, the results of this evaluation demonstrate that remediation of yards with 

lead concentrations that exceed the EPA removal action level of 463 mg/kg would be protective 

for children living in the neighborhood. 

Risk Management Decision: At EPA’s discretion, residential yards and residential yards with 

crawlspaces may be considered for remedial action to mitigate the potential deleterious effects 

associated with exposure to lead in soil based on the neighborhood risk evaluation. 

5.1.4 Deterministic Residential Yard Soil for the Single Residence ) where the 

Survey Indicated Children were Playing in the Crawlspace 

The results of the community survey indicated that a single residence (i.e., ) indicated 

that children played in the crawlspace for 0.5 hour per day; this crawlspace was sampled during 

the OU 3 field investigation and the lead concentration was 443 mg/kg. The front and back 

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yards were sampled during the OU 2 field investigation and had concentrations of 194 mg/kg 

and 766 mg/kg, respectively. Although the back yard was remediated during a previous EPA 

removal action because it exceeded the EPA removal action level of 463 mg/kg, an evaluation of 

potential exposure in the absence of remedial action was conducted. Therefore, the back yard 

concentration of 766 mg/kg was combined with the crawlspace concentration of 443 mg/kg in a 

TWA evaluation (see Table 9). 

The TWA EPC IEUBK modeling results indicate that the percentage of exposed children with an 

estimated blood-lead level exceeding the lead level of concern (10 μg/dL) was 26 percent for the 

2 days per week crawlspace exposure frequency using a TWA EPC of 754 mg/kg; the results of 

the 1 day and 3 days per week exposure frequency scenarios were 25 and 26 percent, 

respectively. These results exceed the EPA OSWER-recommended threshold of 5 percent. 

When modeled concentrations exceed the EPA removal action level of 463 mg/kg and the EPA 

OSWER-recommended threshold of 5 percent is exceeded, then the residential yard is subject to 

a risk management decision (see Figure 9). 

Risk Management Decision: At EPA’s discretion, the back yard at was subject to 

remedial action to mitigate the potential deleterious effects associated with exposure to lead in 

soil. This evaluation provides an example of the EPA risk management decision process, which 

is outlined in Figure 9. 

5.1.5 Deterministic Sensitivity Evaluation to Evaluate Preliminary Remediation Goals for 

Crawlspaces 

The EPA removal action level of 463 mg/kg for residential yards has been established for the 

MDI site. However, a removal action level goal or PRG has not been established for residential 

crawlspaces. The methodology for this evaluation was similar to the TWA residential yard and 

crawlspace evaluation presented in Section 5.1.2, except that the equation was rearranged to 

solve for PbSCrawlspace and the exposure frequency was varied from 1 to 3 days per week (see 

Tables 10 through 12). 

Please note that the deterministic sensitivity evaluation was performed to demonstrate the impact 

of variability and uncertainty of exposure frequency and duration in the crawlspace area on the 

risk and cleanup level(s). A probabilistic evaluation was performed to study the whole range of 

changes in the exposure frequency and duration and quantitatively evaluate the uncertainty in 

these exposure parameters and their effect on the risk and cleanup level. 

TWA results indicate that composite crawlspace soil concentration could vary from 1,500 to 

10,000 mg/kg for the 1 day per week exposure scenario, without exceeding the EPA removal 

action level of 463 mg/kg using the TWA equation and the average OU 2 and OU 3 residential 

yard concentration of 289 mg/kg as inputs. Similarly, the 2 days per week and 3 days per week 

exposure scenarios could have composite crawlspace soil concentrations varying from 900 to 

5,200 mg/kg and 700 to 3,500 mg/kg, respectively. 

It should be noted that if the crawlspace exposure frequency is 2 days per week for 2 hours per 

day, the average OU 2 and OU 3 residential yard concentration is 289 mg/kg, and the EPA 

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removal action level of 463 mg/kg is used as the TWA concentration, then the TWA residential 

crawlspace PRG is 1,509 mg/kg (see Table 11). To place this PRG into context, the composite 

crawlspace soil concentrations varied from 15 to 2,017 mg/kg, with only a single crawlspace 

exceeding 1,509 mg/kg. It should be noted that the crawlspace exposure was based on a 

conservative estimate of exposure (e.g., two days a week exposure to crawlspace soil) that is not 

likely to occur based on the door-to-door surveys. Nevertheless, the crawlspace PRG is fully 

evaluated in the probabilistic risk evaluation. 

Risk Management Decision: It was demonstrated that considering properties with an EPC 

(TWA or otherwise) greater than 463 mg/kg in risk management decisions is appropriate to 

mitigate the potential deleterious effects associated with exposure to lead in soil. 

5.2 PROBABILISTIC RISK ASSESSMENT 

A probabilistic approach was employed to further quantify residential crawlspace exposure. 

Based on EPA methodology, lead is evaluated via the IEUBK Model. The primary site-specific 

input to the IEUBK Model is the EPC. To evaluate crawlspace exposure, EPCs were evaluated 

through a TWA approach based on their low frequency of use and the likelihood that crawlspace 

exposure occurs in conjunction with yard exposure. 

In addition to EPC, a hypothetical crawlspace clean-up value was also forecasted in the 

probabilistic risk assessment. Several scenarios were evaluated in the exposure assessment to 

estimate TWA EPCs for OU 3 incorporating yard and crawlspace concentrations and exposure 

durations. The scenarios evaluated were winter, spring, summer, fall, and annual average to 

capture potential seasonal variations on exposure. While total time spent outside varied with 

season, time spent in the crawlspace was constant throughout the year. 

The scenarios were first evaluated incorporating OU 2 and OU 3 yard and crawlspace data. 

These results are presented as Model Run 1 in Appendix C of the HHRA (EA 2009). The 

scenarios were also evaluated utilizing yard data reflecting a scheduled removal action, for yards 

with detects greater than 463 mg/kg (TTEMI 2005a, 2005b). The yard concentrations scheduled 

for removal action were removed from the data set and replaced with the median background 

concentration of 150 mg/kg (Weston 2004, 2005, 2006). These results are presented as Model 

Run 2 in Appendix C of the HHRA (EA 2009). A summary of these analyses are presented in 

Tables 13 and 14. 

Sensitivity analyses were performed for the residential lead EPC and crawlspace clean-up value 

indicating that the dominant factor is concentration in the yard. The concentration in the 

crawlspace had a much lower impact on the result for EPC and crawlspace clean-up value. 

These results indicate that crawlspace concentration has relatively little contribution to risk from 

lead at the site. 

The results of the probabilistic risk assessment are a distribution of EPCs for lead which can be 

discussed in terms of percentiles for summary purposes. As a potential clean-up level for OU 3 

crawlspaces, the 75th percentile can be used as a starting point for risk management purposes. 

The 75th percentile for incorporating OU 2 and OU 3 yard and crawlspace lead data (Model 

Run 1, pre-removal action) for the crawlspace clean-up goal was 1,612 mg/kg. 

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5.3 UNCERTAINTY SUMMARY 

This HHRA was developed based upon a series of assumptions, which are expected to yield a 

protective evaluation. Even considering the few uncertainties, the potential effect on the results 

of the risk assessment is not expected to introduce significant bias. 

Uncertainty Category 

Potential Effect on the Risk 

Assessment Results 

Potential Effect on the Risk 

Assessment Results 

Soil Data Non-random Sampling Strategy No Potential Bias – Composite Samples 

Collected 

Exposure Scenarios Residential Exposure Potential High Bias for 

Commercial/Industrial Properties 

Exposure Pathways Exposure Pathways Evaluated 

Qualitatively Potential Low Bias 

Exposure Point Concentration Selected Highest Lead 

Concentration Potential High Bias 

IEUBK Modeling Assumptions Default Model Inputs No Potential Bias 

Toxicity Use IEUBK To Evaluate Toxicity Standard Practice – May Bias Risk 

Estimates High 

Risk Characterization Weight of Evidence Approach to 

Evaluate Risk No Potential Bias 

Section 7 of the HHRA (EA 2009) presents the uncertainty analysis in greater detail. 

5.4 HHRA SUMMARY 

The following summaries present the results of the deterministic and probabilistic risk 

evaluations for residential yards and crawlspaces. 

5.4.1 Deterministic Risk Evaluation Summary 

For OU 2, residential yard lead results exceeding the EPA RSL of 400 mg/kg and the EPA 

removal action level of 463 mg/kg were evaluated using the IEUBK Model and considered for 

potential remedial action. 

For OU 3, the neighborhood risk evaluation demonstrated that the percentage of exposed 

children with an estimated blood-lead level exceeding the lead level of concern (10 μg/dL) was 

greater than the EPA OSWER-recommended threshold of 5 percent. Therefore, to mitigate the 

potential deleterious effects associated with exposure to lead in soil, residential yards and 

residential yards with crawlspaces may be considered for remedial action. 

The following risk management decisions will be made at EPA’s discretion: 

• Six residential yards ( ) are 

scheduled for removal action to mitigate the potential deleterious effects associated with 

exposure to lead in soil. 

• Two residential yards ( ) may not be recommended for remedial 

action. 

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• Residential yards with and without crawlspaces with: (1) residential yard concentrations 

exceeding the EPA removal action level of 463 mg/kg; and (2) the estimated percentage 

of children predicted to have a blood-lead levels greater than 10 μg/dL is greater than 5 

percent, may be considered for remedial action to mitigate the potential deleterious 

effects associated with exposure to lead in soil. 

Several uncertainty factors (e.g., the depth issues discussed above and uncertainty in the sources 

of lead and exposure assumptions) should be considered in interpreting these results. 

It should be noted that if the crawlspace exposure frequency is 2 days per week for 2 hours per 

day, the average OU 2 and OU 3 residential yard concentration is 289 mg/kg, and the EPA 

removal action level of 463 mg/kg is used as the TWA concentration, then the limiting 

residential crawlspace concentration is 1,509 mg/kg. To place this into context, the composite 

crawlspace soil concentrations varied from 15 to 2,017 mg/kg, with only a single crawlspace 

exceeding 1,509 mg/kg. It should be noted that the crawlspace exposure was based on a 

conservative estimate of exposure (e.g., 2 days a week exposure to crawlspace soil) that is not 

likely to occur based on the door-to-door surveys. Nevertheless, the crawlspace PRG is fully 

evaluated in the probabilistic risk evaluation. 

Please note that the deterministic sensitivity evaluation was performed to demonstrate the impact 

of variability and uncertainty of exposure frequency and duration in the crawlspace area on the 

risk and cleanup level(s). A probabilistic evaluation was performed to study the whole range of 

changes in the exposure frequency and duration and quantitatively evaluate the uncertainty in 

these exposure parameters and their effect on the risk and cleanup level. 

5.4.2 Probabilistic Risk Evaluation Summary 

A probabilistic evaluation of exposure parameters was performed on OU 2 and OU 3 residential 

yards and crawlspaces. The analysis was performed for all residential yard and crawlspace data 

collected for OU 2 and OU 3 to predict EPCs for combined exposure to yards and crawlspaces, 

as well as to predict clean-up values for lead in crawlspace soil. The analysis also included a 

comparison of crawlspace lead concentrations to background which showed that crawlspace 

concentrations were not consistent with background. 

The probabilistic analysis based on OU 2 and OU 3 yard and crawlspace data showed a 75th

percentile of 348 mg/kg for EPC and of 2,289 mg/kg for clean-up goal based on an annual 

average of time spent outside in yards and crawlspaces (Model Run 2) after scheduled removal 

actions. The probabilistic analysis also showed a 90th percentile of 451 mg/kg for EPC and of 

3,206 mg/kg for clean-up goal. 

Sensitivity analyses were performed for the residential lead EPC and crawlspace clean-up value 

indicating that the dominant factor is concentration in the yard. The concentration in the 

crawlspace had a much lower impact on the result for EPC and crawlspace clean-up value. 

These results indicate that crawlspace concentration has relatively little contribution to risk from 

lead at the site. 

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As a potential clean-up level for OU 3 crawlspaces, the 75th percentile can be used as a starting 

point for risk management purposes. The 75th percentile based on residential yard and 

crawlspace data (Model Run 2, post removal action) for the crawlspace clean-up goal was 2,289 

mg/kg. 

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6. CONCLUSIONS 

This section summarizes the CSM, RI considerations, and risk assessment considerations that 

can be used to determine additional investigatory activities and to aid in remedial decisions for 

the MDI site. 

6.1 CONCEPTUAL SITE MODEL 

The CSM for OU 3 describes offsite airborne particulate deposition of lead from former foundry 

operations (OU 1). OU 3 includes offsite residential crawlspaces and those offsite residential 

areas not addressed under OU 2, which are located within the Modeled Air Deposition Area and 

East Blower Area (Study Area). The potentially complete residential yard and crawlspace soil 

exposure pathways for the current/future offsite adult and child resident include incidental 

ingestion of soil, dermal contact with soil, and inhalation of newly re-suspended airborne soil 

particles; however, the crawlspace exposure is limited to children between the ages of 6 to 84 

months. 

6.2 REMEDIAL INVESTIGATION CONSIDERATIONS 

The distribution of lead in OU 3 residential soil has been well characterized. Figures 6 and 7

present the lead concentrations in soil samples collected from OU 3 crawlspaces and residential 

yards, respectively. 

Due to site access issues, only about 20 percent (20 out of 94 identified) of OU 3 residential 

properties (residences and vacant lots) were evaluated for lead in soil collected from 0 to 1, 0 to 

6, 6 to 12, and 12 to 18 inches bgs. For OU 3 residential yards, lead was detected at 

concentrations equal to or greater than the EPA residential RSL of 400 mg/kg only in the upper 

6 inches of soil, with the highest mean concentration of lead concentrated in the top 1 inch of 

soil. Detected concentrations of lead in OU 3 residential yard soil samples ranged from 14.2 to 

1,190 mg/kg. Six of the 20 OU 3 residential properties sampled had lead concentrations above 

the practical removal action level of 463 mg/kg (established during the OU 2 RI), and will likely 

be addressed during a subsequent EPA removal action. Although the distribution of lead in OU 

3 residential yard soil has been well characterized, additional investigation may be warranted 

once access can be obtained to the remainder of the residential properties that were not addressed 

during the 2003 and 2008 RIs. 

Approximately 40 percent (78 out of 195 identified) of OU 3 residential structures with 

accessible crawlspaces (vertical ground clearance of at least 6 inches) were evaluated to a depth 

of 1 inch bgs. Detected concentrations ranged from 15.03 to 3,204 mg/kg. Although there is no 

EPA RSL for residential crawlspace soil, an action level was evaluated in the HHRA Report (EA 

2009). The distribution of lead in OU 3 residential crawlspace soil has been well characterized. 

Linear regression analysis of the data set indicates that a poor correlation exists between average 

lead concentrations measured in residential exterior paint and corresponding soil-lead 

concentrations for OU 3 crawlspaces and the Background Study Area (i.e., the lead concentration 

detected in the exterior walls of a residential structure not a good predictor of the lead 

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concentration in crawlspace soil). Therefore, lead-based paint is apparently not contributing a 

significant portion of the lead detected in crawlspace soil samples. 

Subsequent lead speciation testing of samples collected from residential crawlspaces and 

corresponding residential drip lines indicated that no significant correlation exists between the 

lead concentrations in crawlspace soil and the lead detected in drip line soil and associated paint 

chips. That is, lead-based paint is apparently not contributing a significant portion of the lead 

detected in crawlspace soil samples. Evaluation of the data indicated that the majority of the 

lead detected in crawlspace soil may be from sources other than lead-based paint. 

6.3 RISK ASSESSMENT CONSIDERATIONS 

Lead results from residential yards and crawlspaces were evaluated in deterministic and 

probabilistic evaluations. 

6.3.1 Deterministic Evaluation 

For OU 2, residential yard lead results exceeding the EPA RSL of 400 mg/kg and the EPA 

removal action level of 463 mg/kg were evaluated using the IEUBK Model and considered for 

potential remedial action. 

For OU 3, the neighborhood risk evaluation demonstrated that the percentage of exposed 

children with an estimated blood-lead level exceeding the lead level of concern (10 μg/dL) was 

greater than the EPA OSWER-recommended threshold of 5 percent. Therefore, to mitigate the 

potential deleterious effects associated with exposure to lead in soil, residential yards, and 

residential yards with crawlspaces may be considered for remedial action. 

The following risk management decisions will be made at EPA’s discretion: 

• Six residential yards are 

scheduled for removal action to mitigate the potential deleterious effects associated with 

exposure to lead in soil. 

• Two residential yards ( ) may not be recommended for remedial 

action. 

• Residential yards with and without crawlspaces with: (1) residential yard concentrations 

exceeding the EPA removal action level of 463 mg/kg; and (2) the estimated percentage 

of children predicted to have a blood-lead levels greater than 10 μg/dL is greater than 5 

percent, may be considered for remedial action to mitigate the potential deleterious 

effects associated with exposure to lead in soil. 

Several uncertainty factors (e.g., the depth issues discussed above and uncertainty in the sources 

of lead and exposure assumptions) should be considered in interpreting these results. 

It should be noted that if the crawlspace exposure frequency is 2 days per week for 2 hours per 

day; the average OU 2 and OU 3 residential yard concentration is 289 mg/kg; and the EPA 

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removal action level of 463 mg/kg is used as the TWA concentration, then the limiting 

residential crawlspace concentration is 1,509 mg/kg. To place this into context, the composite 

crawlspace soil concentrations varied from 15 to 2,017 mg/kg, with only a single crawlspace 

exceeding 1,509 mg/kg. It should be noted that the crawlspace exposure was based on a 

conservative estimate of exposure (e.g., 2 days a week exposure to crawlspace soil) that is not 

likely to occur based on the door-to-door surveys. Nevertheless, the crawlspace PRG is fully 

evaluated in the probabilistic risk evaluation. 

Please note that the deterministic sensitivity evaluation was performed to demonstrate the impact 

of variability and uncertainty of exposure frequency and duration in the crawlspace area on the 

risk and cleanup level(s). A probabilistic evaluation was performed to study the whole range of 

changes in the exposure frequency and duration and quantitatively evaluate the uncertainty in 

these exposure parameters and their effect on the risk and cleanup level. 

6.3.2 Probabilistic Evaluation 

A probabilistic evaluation of exposure parameters was performed on OU 2 and OU 3 residential 

yards and crawlspaces. The analysis was run for all residential yard and crawlspace data 

collected for OU 2 and OU 3 to predict EPCs for combined exposure to yards and crawlspaces, 

as well as to predict clean-up values for lead in crawlspace soil. The analysis also included a 

comparison of crawlspace lead concentrations to background which showed that crawlspace 

concentrations were not consistent with background. 

The probabilistic analysis based on OU 2 and OU 3 yard and crawlspace data showed a 75th

percentile of 558 mg/kg for EPC and of 1,612 mg/kg for clean-up goal based on an annual 

average of time spent outside in yards and crawlspaces (Model Run 1). The probabilistic 

analysis for all of the data showed a 90th percentile of 854 mg/kg for EPC and of 2,466 mg/kg for 

clean-up goal. 

The probabilistic analysis for data reflecting a potential clean-up of yard concentrations showed 

a 75th percentile of 348 mg/kg for EPC and of 2,289 mg/kg for clean-up goal (Model Run 2). 

The probabilistic analysis for all of the data showed a 90th percentile of 451 mg/kg for EPC and 

of 3,206 mg/kg for clean-up goal. 

As a potential clean-up level for OU 3 crawlspaces, the 75th percentile can be used as a starting 

point for risk management purposes. The 75th percentile based on residential yard and 

crawlspace data (Model Run 2) for the crawlspace clean-up goal was 2,289 mg/kg. 

Sensitivity analyses were performed for the residential lead EPC and crawlspace clean-up value 

indicating that the dominant factor is concentration in the yard. The concentration in the 

crawlspace had a much lower impact on the result for EPC and crawlspace clean-up value. 

These results indicate that crawlspace concentration has relatively little contribution to risk from 

lead at the site. 

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6.4 SUMMARY 

Several factors (including the depth issues identified during the HHRA and uncertainty in the 

sources of lead and exposure assumptions) should be considered in interpreting these results. 

Microscopic evaluation and statistical comparisons of the offsite soil data and the onsite soil and 

onsite waste (bag house) data has revealed that the MDI site is not the sole source of elevated 

lead concentrations in Modeled Air Deposition Area and East Blower Area (Study Area) soils. 

Other probable sources include historical deposition from vehicular lead-based fuel emissions 

and residential lead-based paint. 

The deterministic risk assessment evaluated residential yards with and without crawlspaces. 

Those residential yards that may pose potential unacceptable deleterious effects were also 

identified as having potential unacceptable deleterious effects when crawlspace soil (if available) 

was included in the exposure assessment. Naturally, one would conclude that the residential 

crawlspaces must then have potential unacceptable deleterious effects, which would be true if 

children were actually exposed to crawlspace soil. However, the community surveys indicated 

that there was little to no real exposure to crawlspace soils (see Section 3.2). Nevertheless, 

remediation of residential yard and crawlspace soils, if necessary, is a risk management decision 

that EPA will evaluate, as appropriate. Table 15 summarizes all previous and upcoming 

removal actions. 

A probabilistic risk assessment was performed to assess potential lead EPCs capturing the results 

of the site-specific survey for combined residential yard and crawlspace exposure. The 

probabilistic risk assessment also predicted crawlspace cleanup value using site-specific 

exposure information. A sensitivity analysis on the relative influence of input parameters on the 

EPC and crawlspace cleanup value was also performed. 

The probabilistic analysis based on OU 2 and OU 3 yard and crawlspace data (reflecting 

scheduled removal actions) showed a 75th percentile of 348 mg/kg for EPC and of 2,289 mg/kg 

for clean-up goal based on an annual average of time spent outside in yards and crawlspaces 

(Model Run 2). This EPC was below the acceptable OU 2 lead concentration of 463 mg/kg. 

The probabilistic analysis for all of the data showed a 90th percentile of 451 mg/kg for EPC and 

of 3,206 mg/kg for clean-up goal. Based on the conservative nature of the assessment (e.g., use 

of maximum sieved data and use of median background concentration for clean fill used during 

remediation), the probability of a given residence having unacceptable lead risks is low. 

Sensitivity analyses were performed for the residential lead EPC and crawlspace clean-up value 

indicating that the dominant factor is concentration in the yard. The concentration in the 

crawlspace had a much lower impact on the result for EPC and crawlspace clean-up value. 

These results indicate that crawlspace concentration has relatively little contribution to risk from 

lead at the site. 

. 

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REFERENCES 

Eagle Construction & Environmental Services, L.P. 1999. “Final Project Report, MDI 

Residential Area Soil Removal, Houston, Texas, Volume 1.” July. 

EA Engineering, Science, and Technology, Inc. (EA). 2007a. “Health and Safety Plan for 

Remedial Investigation/Feasibility Study Work Plan for Many Diversified Interests, Inc. 

Superfund Site, Operable Unit 3, Houston, Harris County, Texas.” October. 

EA. 2007b. “Site Management Plan for Remedial Investigation/Feasibility Study Work Plan for 

Many Diversified Interests, Inc. Superfund Site, Operable Unit 3, Houston, Harris County, 

Texas.” December. 

EA. 2007c. “Sampling and Analysis Plan, Remedial Investigation/Feasibility Study, Many 

Diversified Interests, Inc. Superfund Site, Operable Unit 3.” Prepared for EPA Region 6. 

December. 

EA. 2008a. “Remedial Investigation/Feasibility Study Work Plan (Revision 02), Many 

Diversified Interests, Inc. Superfund Site, Operable Unit 3, Houston, Harris County, Texas.” 

July. 

EA. 2008b. “Data Evaluation Summary Report, Remedial Investigation/Feasibility Study, 

Many Diversified Interests, Inc. Superfund Site, Operable Unit 3.” Prepared for EPA Region 

6. November. 

EA. 2009. “Human Health Risk Assessment Report, Remedial Investigation/Feasibility Study 

(Revision 01), Many Diversified Interests, Inc. Superfund Site, Operable Unit 3.” Prepared 

for EPA Region 6. April. 

Tetra Tech EM Inc. (TTEMI). 2003. “Data Evaluation Summary Report, Operable Unit 2, 

Remedial Investigation and Feasibility Study, Many Diversified Interests Superfund Site, 

Houston, Texas.” December. 

TTEMI. 2005a. “Human Health Risk Assessment Report for Operable Unit 2, Many 

Diversified Interests, Inc. Superfund Site.” July. 

TTEMI. 2005b. “Remedial Investigation Report for Operable Unit 2, Many Diversified 

Interests, Inc. Superfund Site.” July. 

Texas Commission on Environmental Quality (TCEQ). 2007. “Texas Risk Reduction Program, 

Texas Background Levels.” July. 

U.S. Environmental Protection Agency (EPA). 1994. Guidance Manual for the IEUBK Model 

for Lead in Children. Office of Solid Waste and Emergency Response (OSWER). 

Washington, D.C. PB93-963510 OSWER #9285.7-15-1. February. 

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EPA. 1995. Record of Decision, RSR Corporation Superfund Site, Operable Unit No. 1 - 

Residential Property, Dallas, Texas. May. 

EPA. 1997. Record of Decision, Residential Areas, Operable Unit 2, Tar Creek Superfund Site, 

Ottawa County, Oklahoma. EPA Region 6. August. 

EPA. 1998. EPA SW-846 Method 6200—Field Portable X-Ray Fluorescence Spectrometry for 

Determination of Elemental Concentrations in Soil and Sediment. Office of Solid Waste. 

January. 

EPA. 2000a. TRW Recommendations for Sampling and Analysis of Soil at Lead (Pb) Sites. 

Office of Emergency and Remedial Response (OERR). EPA-540-F-00-010. OSWER 

#9285.7-38. April. 

EPA. 2000b. Record of Decision, Delatte Metals Superfund Site, Ponchatoula/Tangipahoa 

Parish, Louisiana. EPA Region 6. September. 

EPA. 2004. Record of Decision, Many Diversified Interests Superfund Site, Operable Unit 1 

(On-Site Soils and Ground Water). July. 

EPA. 2005a. Record of Decision, Many Diversified Interests Superfund Site, Operable Unit 2 

(Off-Site Residential Yards and High-Access Areas). September. 

EPA. 2005b. Integrated Exposure Uptake Biokinetic Model for Lead in Children, Windows 

Version (IEUBKwin v1.0, build 264). December. Available on-line: 

http://www.epa.gov/superfund/health/contaminants/lead/products.htm#ieubk

EPA. 2006. Agreed Order on Consent, Many Diversified Interests, Inc. Superfund Site. Docket 

No. 06-12-05. EPA Region 6. September. 

EPA. 2007a. User’s Guide for the Integrated Exposure Uptake Biokinetic Model for Lead in 

Children (IEUBK) Windows Version-32 bit Version (EPA 9285.7-42). Updated. OSWER. 

May. 

EPA. 2007b. “RAC II Fixed Rate Statement of Work (Revision 01) for Remedial 

Investigation/Feasibility Study, Many Diversified Interests, Inc. Superfund Site, Operable 

Unit 3, Houston, Harris County, Texas.” September. 

EPA. 2007c. “EPA Region 6 Human Health Medium Specific Screening Levels.” December. 

On-line address: http://www.epa.gov/earth1r6/6pd/rcra_c/pd-n/screen.htm 

EPA. 2008. Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites. 

RSL Table Update. September. 

Weston Solutions, Inc. (Weston). 2004. “MDI Off-Site Properties Removal Report, Houston, 

Harris County, Texas.” Prepared for EPA Region 6. March. 

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Many Diversified Interests Operable Unit 3 Remedial Investigation 

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Weston. 2005. “Addendum to the MDI Off-Site Properties Removal Report, Houston, Harris 

County, Texas.” Prepared for EPA Region 6. June. 

Weston. 2006. “Acknowledgement of Completion Report for MDI Off-Site Properties 

Removal, Third Addendum, 3617 Baer Street, Houston, Harris County, Texas.” Prepared for 

EPA Region 6. June. 

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GLOSSARY

Adenovirus – A virus that causes upper respiratory infection. 

Adverse Health Effect – A change in body function or cell structure that may lead to disease or 

health problems. 

Alveoli – An air sac in the lung where gases are exchanged. 

Anthropogenic – Of, relating to, or resulting from the influence of human beings on nature (for 

example, anthropogenic pollution). 

Arithmetic Mean – The average of a set of numbers. The arithmetic mean is calculated by 

adding all of the values in a data set, then dividing by the number of values. 

Background Level – An average or expected amount of a substance in a specific environment, or 

typical amounts of substances that occur naturally in an environment. 

Biliary – Pertaining to bile, a digestive juice secreted by the liver and stored in the gall bladder. 

Biokinetics – The study of movements of or within organisms. 

Cancer – A disease of inheritable, bodily mutations that affect cell growth and differentiation. 

Cancer is characterized by an abnormal, uncontrolled growth of cells. 

Cancer Risk – A theoretical risk for getting cancer if exposed to a substance every day for 

70 years (a lifetime exposure). The true risk may be lower. 

Carcinogen – A substance that causes cancer. 

Carcinogenic – Causing cancer. 

Comprehensive Environmental Response, Compensation, and Liability Act of 1980 

(CERCLA) – CERCLA, also known as Superfund, is the federal law that concerns the removal 

or clean-up of hazardous substances in the environment and at hazardous waste sites. 

Concentration – The relative amount of a substance in an environmental medium, expressed by 

relative mass (such as milligrams per kilogram, mg/kg), volume (such as milliliters per liter, 

ml/L), or number of units (such as parts per million, ppm). 

Conceptual Site Model (CSM) – A Conceptual Site Model, which is a key element used in 

facilitating clean-up decisions during a site investigation, is a planning tool that organizes 

information that already is known about a site and identifies the additional information necessary 

to support decisions that will achieve the goals of the project. The project team uses the CSM to 

direct field work that focuses on the information needed to remove significant unknowns from

the model. The CSM serves several purposes—as a planning instrument; as a modeling and data 

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interpretation tool; and as a means of communication among members of a project team, 

decision makers, stakeholders, and field personnel. 

Confidence Interval – A confidence interval gives an estimated range of values that is likely to 

include an unknown population parameter. This estimated range is calculated from a given set of 

sample data. 

Contaminant – A substance that is either present in an environment where it does not belong or 

is present at levels that might cause harmful (adverse) health effects. 

Contaminant of Potential Concern (COPC) – A substance that is potentially site-related and 

whose data are of sufficient quality for use in a quantitative risk assessment. 

Correlation – An estimate of the degree to which two sets of variables vary together, with no 

distinction between dependent and independent variables. 

Dermal Contact – Contact with (touching) the skin. 

Detection Limit – The lowest concentration of a substance that can be distinguished reliably 

from a concentration of zero. 

Deterministic Analysis (as opposed to probabilistic analysis) – Calculation and expression of 

health risks as single numerical values or “single point” estimates of risk. In risk assessments, 

the uncertainty and variability are discussed in a qualitative manner. 

Discrete Data – A set of data is said to be discrete if its values are distinct and separate (that is, 

they can be counted: 1, 2, 3...).

Dose – A measure of exposure. Examples include (1) the amount of a substance ingested, (2) the 

amount of a substance absorbed, and (3) the product of ambient exposure concentration and the 

duration of exposure. 

Dose-Response Assessment – A determination of the relationship between the magnitude of an 

administered, applied, or internal dose and a specific biological response. Response can be 

expressed as measured or observed incidence or change in level of response, percent response in 

groups of subjects (or populations), or the probability of occurrence or change in level of 

response within a population. 

Empirical – Derived from experiment or observation, rather than theory. 

Encephalopathy – A disease or disorder of the brain. 

Endpoint – An observable or measurable biological event or chemical concentration (e.g., 

metabolite concentration in a target tissue) used as an index of an effect of a chemical exposure. 

Erythrocytes – Red blood cells. 

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Exposure – Contact with a substance by swallowing, breathing, or touching the skin or eyes. 

Exposure may be short-term (acute), of intermediate duration, or long-term (chronic). 

Exposure Assessment – The process of finding out how people come into contact with a 

hazardous substance, how often and for how long they are in contact with the substance, and how 

much of the substance they are in contact with. 

Exposure Medium – The contaminated environmental medium to which an individual is 

exposed, such as soil, water, sediment, and air. 

Exposure Pathway – The route a substance takes from its source (where it began) to its end 

point (where it ends), and how people can come into contact with (or be exposed to) it. An 

exposure pathway has five parts: a source of contamination (such as an abandoned business); an 

environmental media and transport mechanism (such as movement through ground water); a 

point of exposure (such as a private well); a route of exposure (eating, drinking, breathing, or 

touching); and a receptor population (people potentially or actually exposed). When all five 

parts are present, the exposure pathway is termed a completed exposure pathway. 

Exposure Point – The potential contact between a person and a contaminant within an exposure 

medium. 

Exposure Point Concentration – The value that represents a conservative estimate of the 

chemical concentration available from a particular medium or route of exposure. 

Exposure Route – The mechanism for which a contaminant comes in contact with a person (for 

example, by ingestion, inhalation, dermal contact). 

Exposure Scenario – A set of assumptions concerning how an exposure takes place, including 

assumptions about the exposure setting, stressor characteristics, and activities of an organism that 

can lead to exposure. 

Feasibility Study – A study by EPA to determine the best way to clean up environmental 

contamination. A number of factors are considered, including health risk, costs, and what 

methods will work well. 

Geometric Mean – A type of mean (or average) that indicates the central tendency or typical 

value in a set of numbers. The geometric mean is similar to the arithmetic mean, but instead of 

adding the set of values and dividing by the total number of values in a set, the numbers are 

multiplied and the nth root (where “n” is the number of values in the set) of the resulting product 

is taken. For example, if there are two values in a set, the numbers are multiplied, then the 

square root is taken; if there are three values in a set, the numbers are multiplied, then the cube 

root is taken. 

Glomerular Filtration – The flow of fluid through the kidney. 

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Hazard Characterization – A description of the potential adverse health effects attributable to a 

specific environmental agent, the mechanisms by which agents exert their toxic effects, and the 

associated dose, route, duration, and timing of exposure. 

Hematopoietic – Pertaining to the formation of blood or blood cells. 

Heme – The component of hemoglobin that is responsible for binding oxygen. 

Hemoglobin – A protein-based component of red blood cells that is primarily responsible for 

transferring oxygen from the lungs to the rest of the body. Hemoglobin, which is produced in 

the bone marrow as needed, causes red blood cells to appear red. 

Human Health Risk Assessment (HHRA) – Estimates the current and possible future risk if no 

action were taken to clean up a site. EPA’s Superfund risk assessors determine how threatening 

a hazardous waste site is to human health and the environment. They seek to determine a safe 

level for each potentially dangerous contaminant present (for example, a level at which ill health 

effects are unlikely and the probability of cancer is very small). Living near a Superfund site 

does not automatically place a person at risk; risk depends on the substances(s) present and how 

a person is exposed to the substance(s). 

Hypothesis – A proposition set forth as an explanation for a specified phenomenon or group of 

phenomena. 

In Situ – A Latin term meaning "in its original place" or "onsite." In other words, in situ

material is unexcavated and unmoved. 

In Vivo – A Latin term meaning “in the living organism.” 

Incidence – The number of new cases of disease in a defined population over a specific time 

period. 

Ingestion – The act of swallowing something through eating, drinking, or putting something in 

one’s mouth. A contaminant can enter the body this way. 

Inhalation – The act of breathing. A contaminant can enter the body this way. 

Isopleth – A line connecting points at which a given variable has a specified constant value. 

Iteration – Repetition. 

Linear Regression – The process of fitting the best possible straight line through a series of 

points. Linear regression is often used to reduce a set of points to a simple mathematical 

relationship or to deduce the underlying trends from a set of measurements that are expected, on 

theoretical grounds, to follow a straight line. 

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Lognormal Distribution – A probability distribution in which the logarithm of the parameter has 

a normal distribution. 

Lysosomes – Membranous cells containing enzymes. 

Mean – Average. The mean is calculated by adding all values in a set, then dividing by the total 

number of values. 

Media – Specific environmental elements—air, water, soil—which are the subject of regulatory 

concern and activities. 

Median – A value that is halfway through an ordered set of data, before and after which there are 

an equal number of data values. 

Medium – The environmental element (such as air, water, soil) originally contaminated. 

Metabolism – The range of biochemical processes that occur within a living organism. 

Metabolism consists both of anabolism (buildup of substances) and catabolism (breakdown of 

substances). 

Mitochondria – Small complex structures that occur in every cell of the body. 

Monte Carlo Evaluation – A repeated random sampling from the distribution of values for each 

of the parameters in a calculation (for example, lifetime average daily exposure), to derive a 

distribution of estimates (of exposures) in the population. 

Mutagenicity – The ability to cause mutations. Mutations occur when a DNA gene is damaged 

such that it alters the genetic message carried by that gene. 

National Priorities List (NPL) – The list compiled by EPA of uncontrolled hazardous substance 

releases in the United States that are priorities for long-term evaluation and response. 

Nephropathy – A disease or disorder of the kidneys. 

Neurologic System – Nervous system. 

Noncarcinogenic – Not causing cancer. 

Normal Distribution – A continuous probability distribution that describes data that clusters 

around a mean or average value. The graph associated with the normal distribution is bell 

shaped, with a peak at the mean or average value. 

Null Hypothesis – A statement (represented as Ho) about unknown parameters in a population 

that is to be assessed based on sample results. The null hypothesis is put forward either because 

it is believed to be true or because it will be used as a basis for argument but has not yet been 

proven. 

034530
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Many Diversified Interests Operable Unit 3 Remedial Investigation 

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Operable Unit – An operable unit is a discrete action that comprises an incremental step toward 

comprehensively addressing site contamination. 

Parameter – Constants applied to a model that are obtained by theoretical calculation or 

measurements taken at another time and/or place, and are assumed to be appropriate for the place 

and time being studied. 

Percentile – Values that divide a sample of data into one hundred groups containing (as far as 

possible) equal numbers of observations. For example, 50 percent of the data values lie below 

the 50th percentile. 

Pharmacokinetics – The study of what happens to a substance in the body, including how the 

substance gets into the body, where it goes in the body, how it is changed by the body, and how 

it leaves the body. 

Pica – The eating of non-food substances. 

Plasma – The liquid portion of blood. 

Population – An entire collection of people, animals, plants, or things from which data are 

collected. 

Preliminary Remediation Goal (PRG) – A concentration level set for an individual substance 

that, for carcinogens, corresponds to a specific cancer risk level of 1 in 1 million, and for 

noncarcinogens corresponds to a hazard quotient of 1. The hazard quotient is the ratio of 

estimated site-specific exposure to a single substance from a site over a specified period to the 

estimated daily exposure level, at which no adverse health effects are likely to occur. 

Probabilistic Assessment (as opposed to deterministic assessment) – Calculation and expression 

of health risks using multiple risk descriptors to provide the likelihood of various risk levels. 

Probabilistic risk results approximate a full range of possible outcomes and the likelihood of 

each, which often is presented as a frequency distribution graph, thus allowing uncertainty or 

variability to be expressed quantitatively. 

Probability – A quantitative description of the likelihood of a particular event, conventionally 

expressed on a scale from 0 to 1. A rare event has a probability nearer to 0, whereas a common 

event has a probability nearer to 1. 

Qualitative Data (as opposed to quantitative data) – Data that is based on qualities, not 

measurements. 

Quantitative Data (as opposed to qualitative data) – Data that is based on measurements. 

Receptor – Someone who could come into contact with a contaminant. 

034531
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Record of Decision (ROD) – A public document that explains which clean-up alternative(s) will 

be used at National Priorities List sites where, under CERCLA, Trust Funds pay for the clean-up. 

Reference Dose (RfD) – An estimate of a daily oral exposure to humans that is likely to not 

cause significant risk of adverse effects during a lifetime. 

Remedial Action – The actual construction or implementation phase of a Superfund site clean-up 

that follows Remedial Design. 

Remedial Investigation – The process of determining the type and extent of hazardous material 

contamination at a site. 

Removal Action – The clean-up or removal of hazardous substances from the environment 

which may be taken in the event of the threat of release of hazardous substances into the 

environment. 

Risk – The probability of adverse effects resulting from exposure to an environmental agent or 

agents. 

Risk Assessment (in the context of human health) – The evaluation of scientific information on 

the hazardous properties of environmental agents (hazard characterization), the dose-response 

relationship (dose-response assessment), and the extent of human exposure to those agents 

(exposure assessment). The product of the risk assessment is a statement regarding the 

probability that exposed populations or individuals will be harmed and to what degree (risk 

characterization). 

Risk Characterization – The integration of information on hazard, exposure, and dose-response 

to provide an estimate of the likelihood that any of the identified adverse effects will occur in 

exposed people. 

Sample – A portion or piece of a whole; a selected subset of a population or subset of whatever 

is being studied. For example, an environmental sample (such as a small amount of soil or 

water) might be collected to measure contamination in the environment at a specific location. 

Sensitivity – In relation to toxic substances, organisms that are more sensitive exhibit adverse 

(toxic) effects at lower exposure levels than organisms that are less sensitive. 

Significance Level – A fixed probability of incorrectly rejecting the null hypothesis, when in fact 

it is true. 

Slope Factor – An upper bound, approximating a 95 percent confidence limit, on the increased 

cancer risk from a lifetime exposure to a contaminant. This estimate, usually expressed in units 

of proportion (of a population) affected per milligram per kilogram per day (mg/kg-day), is 

generally reserved for use in the low-dose region of the dose-response relationship, that is, for 

exposures corresponding to risks less than 1 in 100. 

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Standard Deviation – A measure of variability representing an average distance of the data from 

the mean (or average). 

Standard Error – Standard error is the standard deviation of the values of a given function of the 

data (parameter), over all possible samples of the same size. 

Statistical Significance – Data is said to be statistically significant when the discrepancy 

between the sample evidence and the null hypothesis is too large or improbable to be attributed 

to chance. That is, it is the probability that a result is not likely to be due to chance alone. 

Superfund – Federal authority, established by the Comprehensive Environmental Response, 

Compensation, and Liability Act (CERCLA) in 1980, to respond directly to releases or 

threatened releases of hazardous substances that may endanger health or welfare. 

Systemic Toxicity – Systemic toxicity includes the toxic effects that result from absorption and 

distribution of a toxicant to the body in a general, rather than a local manner. 

Threshold – The dose or exposure below which no harmful effect is expected to occur. 

Toxicity – Harmful biological effects caused by a chemical, physical, or biological agent. 

Toxicity Assessment – Review of literature, results of toxicity tests, and data from field surveys 

regarding the toxicity of any given material to a receptor. 

Toxicity Value – A numerical expression of a substance’s exposure-response relationship that is 

used in risk assessments. 

Toxicokinetics – The application of pharmacokinetics to determine the relationship between the 

systemic exposure of a compound in experimental animals and its toxicity. It is used primarily 

for establishing relationships between exposures in toxicology experiments in animals and the 

corresponding exposures in humans. 

Toxicology – The study of harmful interactions between chemical, physical, or biological agents 

and biological systems. 

Transmucosal – Diffusion through a mucous membrane. 

Transplacental – Passing through or occurring across the placenta, the membranous organ that 

develops during pregnancy, lining the uterine wall and partially enveloping the fetus, to which it 

is attached by an umbilical cord. 

Uncertainty – Uncertainty refers to the inability to know for sure—it is often due to incomplete 

data. For example, when assessing the potential for risks to people, toxicology studies generally 

involve dosing of sexually mature test animals such as rats as a surrogate for humans. Since it is 

unknown how differently humans and rats respond, EPA often employs the use of an uncertainty 

factor to account for possible differences. Additional consideration may also be made if there is 

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some reason to believe that the very young are more susceptible than adults, or if key toxicology 

studies are not available. 

Upper Confidence Level of the Mean (UCLM) – The upper confidence level defines a value that 

equals or exceeds the true mean (or average). The 95 percent UCLM exceeds the true mean 95 

percent of the time. 

Uptake – A process by which materials are transferred into or onto an organism. 

Variability – This refers to the range of toxic response or exposure—for example, the dose that 

might cause a toxic response can vary from one person to the next depending on factors such as 

genetic differences or preexisting medical conditions. Exposure may vary from one person to 

the next depending on factors such as where one works, time spent indoors or out, where one 

lives, how much people eat or drink, etc. 

Wilcoxon Rank Sum Test – A test that compares the median of a single column of numbers 

against a hypothetical median. 

X-Ray Fluorescence – The emission of secondary (fluorescent) X-rays from a material that has 

been bombarded with high-energy X-rays or gamma rays. X-ray fluorescence is used to analyze 

elements and chemicals. 

Xenobiotic – A substance found in an organism but which is not normally produced or expected 

to be present in it, or a substance found in an organism at a higher level than expected.

034534
Tables

034535
TABLE 1 SUMMARY OF PROPERTIES (YARDS) ADDRESSED DURING PREVIOUS INVESTIGATIONS AND REMOVAL ACTIONS (1999 

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Property Type

Located Within 

Modeled Air 

Deposition Area and 

East Blower Area

Located Outside of 

Modeled Air 

Deposition Area and 

East Blower Area Total

Located Within 

Modeled Air 

Deposition Area and 

East Blower Area

Located Outside of 

Modeled Air 

Deposition Area and 

East Blower Area Total

OU 2 Properties 

Sampled During 

2003 OU 2 RI

OU 2 Proper

Lead in Soi

Cleanup Le

mg/k

Residential 180 35 215 40 29 69 133 37 Vacant lot 98 38 136 10 10 20 33 16 

Public housing 1 0 1 0 0 0 1 1 

Commercial/industrial 25 5 30 0 0 0 6 1 Public use 2 0 2 0 0 0 2 1 

Church 5 1 6 0 0 0 5 3 

School 1 0 1 0 0 0 1 1 

Daycare center 0 0 0 0 0 0 0 0 

TOTAL 312 79 391 50 39 89 181 60 

Notes:

1

EPA U.S. Environmental Protection Agencymg/kg Milligram per kilogramOU 2 Operable Unit 2 (Modeled Air Deposition Area and East Blower Area)RI Remedial InvestigationTNRCC Texas Natural Resource Conservation Commission (now known as the Texas Commission on Environmental Quality)

Summary of Properties Investigated

Summary of Properties Remediated during TNRCC 

Removal Action (1999)

Summary of OU 2 Investigatio

2

OU 2 RI only addressed those yards and high-access areas located within the Modeled Air Deposition Area and East Blower Area. 

Modeled Air Deposition Area is defined as the predicted impact area corresponding to lead concentrations ranging greater than 400 mg/kg (bound by the 0.8 gram per square meter per year le

034536
TABLE 2 SUMMARY OF PROPERTY ACCESS AND SAMPLING FOR RESIDENTIAL CRAWL

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Description

Within the Modeled 

Air Deposition Area and 

East Blower Area

Outside of the Modeled 

Air Deposition Area and 

East Blower Area 

Total No. of Residences with Accessible Crawlspaces 199 7 Total No. of Residences with Inaccessible Crawlspaces 26 0 

Total No. of Residences with Accessible Crawlspaces Sampled During 2003 OU 2 RI 23 6 

Total No. of Residences with Accessible Crawlspaces Sampled During 2008 OU 3 RI 78 1 0 

Total No. of Residences with No Crawlspaces-Concrete Slabs 18 0 

Total No. of Residences with Access Obtained for Crawlspaces 90 0 

Total No. of Residences with Access Not Obtained for Crawlspaces 109 0 Notes:

1 One residential crawlspace sampled during the 2003 OU 2 RI was inadvertently re-sampled during the 2008 OU 3 RI.

EPA U.S. Environmental Protection Agencymg/kg milligram(s) per kilogram OU Operable UnitRI Remedial InvestigationModeled Air Deposition Area is defined as the predicted impact area corresponding to lead concentrations ranging greater than 400 mg/kg (bound square meter per year lead isopleth).

034537
TABLE 3 SUMMARY OF PROPERTY ACCESS AND SAMPLING FOR RESIDENTIAL YARDS AND HIGH-ACC

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Property Type

Total No. of Residential Yards and 

High-Access Areas with Access 

Granted/Secured and Sampled During 

2003 OU 2 RI

Total No. of Residential Yards and High-Access Areas Where 

Access Was Not Granted/Secured 

During 2003 OU 2 RI

Total No. of Residential Properties 

with Access Granted/Secured and 

Sampled During 2008 OU 3 RI

Total 

High-A

N

Residential 133 53 14 

Vacant lot 33 41 6 Public housing 1 00 

Commercial/industrial 6 0 0 

Public use 2 0 0 

Church 5 0 0 

School 1 0 0 

Daycare center 0 00 

TOTAL 181 94 20 

Notes:EPA U.S. Environmental Protection Agencymg/kg milligram(s) per kilogramOU Operable UnitRI Remedial Investigation

Summary of Property Access within the Modeled Air Deposition Area and East Blower Area

Modeled Air Deposition Area is defined as the predicted impact area corresponding to lead concentrations ranging greater than 400 mg/kg (bound by the 0.8 gram per squar

034538
Lead 400 mg/kg b 150.5 140 94.6 38.45 

Lead NE 273.2 NA NA NA 

TABLE 4 SUMMARY OF SCREENING CRITERIA

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

AnalyteResidential Yard Soil (median concentration in OU 2 residential yard soil samples collected in the Background Study Area)Residential Crawlspace Soil (Median concentration in OU 3 residential crawlspace soil samples collected in the Background Study Area)

Site-specific Median Background by Depth Interval 

(mg/kg) 

0 ‐ 1 inch bgs 0 ‐ 6 inches bgs 6 ‐ 12 inches bgs 12 ‐ 18 inches bgs

Screening Criteria

a Texas Commission on Environmental Quality 2007

Notes:NA not applicableNE not established

b EPA Regional Screening Level (EPA 2008)

bgs below ground surfacemg/kg milligram(s) per kilogramEPA U.S. Environmental Protection Agency

034539
Top Bottom

RY-1005-0-6-U 0 6 573.64

RY-1005-0-6-U1 0 6 546

RY-1006-0-6-U-D 0 6 963.01

RY-1006-0-6-U 0 6 962.77

RY-1006-0-1-S 0 1 744.67

RY-1006-0-1-U 0 1 672.98

RY-1007-0-1-S 0 1 1,190RY-1007-0-1-S 0 1 1,155.81

RY-1007-0-6-U 0 6 785.72

RY-1013-0-1-S 0 1 1,146.46

RY-1013-0-6-U 0 6 989.06

RY-1014-0-1-U 0 1 777.59

RY-1014-0-1-S 0 1 622.91

RY-1027-0-6-U 1 0 6 532 6 Norther

Notes:

1 Fixed laboratory sample (i.e., not X-ray fluorescence sample)

bgs below ground surfaceD field duplicate samplemg/kg milligram(s) per kilogramS sieved sampleU unsieved sample

TABLE 5 LEAD CONCENTRATIONS EXCEEDING 463 MG/KG FOR OPERABLE UNIT 3 RESIDEN

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Soil Depth Interval 

(inches bgs)

Maximum Depth of Soil 

with Lead ≥ 463 mg/kg 

(inches bgs)

666

Sample ID

Maximum Lead 

Concentration 

Address Key (mg/kg)

1

Entire psingle-fEntire psingle-fEntire psingle-fEntire pduplexEntire pduplex

6

034540
TABLE 6 COMPARISON OF LEAD CONCENTRATIONS IN EXTERIOR PAINT AND CORRESPONDING CR

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

In Situ Exterior Paint (mg/cm2

) Maximum Crawlspace Soil Conc

4.36 278.06

4.254 464.953.128 278.06

2.76 363.44

2.3 775.97

1.978 504.391.966 250.43

1.6 1185.11

1.516 335.721.284 285.751.034 248.56

1.012 1166.23

Notes:XRF X-ray fluorescence

XRF Lead Concentration (Operable Unit 3)

Address

EPA U.S. Environmental Protection Agencymg/kg milligram(s) per kilogrammg/cm2 milligram(s) per square centimeter

034541
MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Address Keya Property Description Sample ID a

Highest Lead

Concentration b

(mg/kg) 

Geometric Mean

Blood-Lead Level c

(μg/dL) Percent Above d

Single-family residence RY-1005 574 6.0 14

Single-family residence RY-1006 963 8.8 39

Single-family residence RY-1007 1,190 10 52

Single-family residence RY-1026 256 3.4 1.1

Single-family residence RY-1025 280 3.6 1.5

Single-family residence RY-1009 374 4.4 4.0

RY-1003 242 3.3 0.85

RY-1004 284 3.6 1.5

RY-1011 251 3.3 0.98

RY-1012 155 2.5 0.15

RY-1017 209 3.0 0.48

RY-1018 416 4.7 5.6

Single-family residence RY-1015 166 2.6 0.20

Single-family residence RY-1016 155 2.5 0.15

Single-family residence RY-1008 293 3.7 1.7

Single-family residence RY-1010 290 3.7 1.7

Duplex RY-1013 1,146 10 50

Duplex RY-1014 778 7.5 27

RY-1027 532 5.7 11

RY-1028 177 2.7 0.25

RY-1019 143 2.4 0.11

RY-1020 289 3.7 1.7

RY-1021 185 2.8 0.30

RY-1022 81 1.8 0.012

RY-1023 130 2.2 0.074

RY-1024 143 2.4 0.11

RY-1000 320 3.9 2.4

RY-1001 234 3.2 0.75

RY-1002 85 1.8 0.015

Notes:

a 

b 

c 

d 

bgs = below ground surface

EPA = U.S. Environmental Protection Agency

IEUBK = Integrated Exposure and Uptake Biokinetic

mg/kg = milligram(s) per kilMilligram per kilogram

μg/dL = microgram(s) per deciliter

TABLE 7A DETERMINISTIC IEUBK MODEL RESULTS FOR OU 3 RESIDENTIAL AREAS WITHOUT 

CRAWLSPACE EXPOSURE

Single-family residence

Vacant lot

Single-family residence

Vacant lot

Geometric mean blood-lead level for a child calculated over 6 to 84 months (or 0 to 7 years); the blood-lead level was 

determined using the IEUBK Model for Lead in Children (EPA 2003b). The measured soil concentration was used as 

the model input. The data set was limited to residential properties only and censored for duplicate results.

Shaded cells denote locations that exceed the lead level of concern (10 μg/dL) more than 10% and 463 mg/kg is 

exceeded.

Figure A-1 of Appendix A presents location IDs. Table A-1 of Appendix A presents a comprehensive cross-reference 

of sample location IDs and sample numbers.

Vacant lot

Vacant lot

Vacant lot

Vacant lot

The background concentration for lead in soil (0 to 0.08 foot bgs) is 150.5 mg/kg; using the background value was 

considered more protective than the clean fill concentration of 5 mg/kg lead used during previous removal actions.

Page 1 of 1

034542
MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Address Keyb Property Description Sample ID c

Highest Lead

Concentration d

(mg/kg) 

Geometric Mean

Blood-Lead Level e

(μg/dL) Percent Above f

Single-family residence RY-1005 a 150 2.4 0.13

Single-family residence RY-1006 a 150 2.4 0.13

Single-family residence RY-1007 a 150 2.4 0.13

Single-family residence RY-1026 256 3.4 1.1

Single-family residence RY-1025 280 3.6 1.5

Single-family residence RY-1009 374 4.4 4.0

RY-1003 242 3.3 0.85

RY-1004 284 3.6 1.5

RY-1011 251 3.3 0.98

RY-1012 155 2.5 0.15

RY-1017 209 3.0 0.48

RY-1018 416 4.7 5.6

Single-family residence RY-1015 166 2.6 0.20

Single-family residence RY-1016 155 2.5 0.15

Single-family residence RY-1008 293 3.7 1.7

Single-family residence RY-1010 290 3.7 1.7

Duplex RY-1013 a 150 2.4 0.13

Duplex RY-1014 a 150 2.4 0.13

RY-1027 a 150 2.4 0.13

RY-1028 177 2.7 0.25

RY-1019 143 2.4 0.11

RY-1020 289 3.7 1.7

RY-1021 185 2.8 0.30

RY-1022 81 1.8 0.012

RY-1023 130 2.2 0.074

RY-1024 143 2.4 0.11

RY-1000 320 3.9 2.4

RY-1001 234 3.2 0.75

RY-1002 85 1.8 0.015

Notes:

a

b

c 

d Lead concentration 

e 

f 

bgs = below ground surface

EPA = U.S. Environmental Protection Agency

IEUBK = Integrated Exposure and Uptake Biokinetic

mg/kg = milligram(s) per ki Milligram per kilogram

μg/dL = microgram(s) per deciliter

Vacant lot

Vacant lot

Vacant lot

The percentage of exposed children that would have a blood-lead level exceeding the lead level of concern (10 μg/dL).

Scheduled removal of yard soil with concentrations above the OU 3 clean-up goal of 463 mg/kg and replaced with clean 

backfill having a lead concentration of approximately 5 mg/kg. The conservative value of 150 mg/kg used in these 

calculations represents the background lead concentration for the Study Area. Shaded cells denote locations where the 

yard concentration was replaced by the background lead concentration for the study area (150 mg/kg).

Vacant lot

Vacant lot

Figure A-1 of Appendix A presents location IDs. Table A-1 of Appendix A presents a comprehensive cross-reference of 

sample location IDs and sample numbers.

Geometric mean blood-lead level for a child calculated over 6 to 84 months (or 0 to 7 years); the blood-lead level was 

determined using the IEUBK Model for Lead in Children (EPA 2003b). The measured soil concentration was used as 

the model input. The data set was limited to residential properties only and censored for duplicate results.

The background concentration for lead in soil (0 to 0.08 foot bgs) is 150.5 mg/kg; using the background value was 

considered more protective than the clean fill concentration of 5 mg/kg lead used during previous removal actions.

Single-family residence

TABLE 7B DETERMINISTIC IEUBK MODEL RESULTS FOR OU 3 RESIDENTIAL AREAS 

AFTER SCHEDULED REMOVAL ACTIONa

Single-family residence

Vacant lot

Page 1 of 1

034543
Address Key Property Description Sample ID a

Highest Near Surface 

Composite Yard Soil 

Concentration 

(0-1 inch or 

0-6 inches bgs) 

(mg/kg)

Composite 

Crawlspace Soil 

Concentration 

(mg/kg)

Time-Weighted 

Average (TWA) 

Soil Lead 

Concentrationb

(mg/kg) 

Geometric 

Mean

Blood-Lead 

Level c

(μg/dL)

Percent 

Above d

Single-family residence RY-1005 574 -- 574 6.0 14

Single-family residence RS-0326 975 693 934 8.6 38

Single-family residence RY-1006 963 1,185 995 9.0 41

Single-family residence RY-1007 1,190 1,166 1,187 10.3 52

Single-family residence RY-1026 256 -- 256 3.4 1.1

Single-family residence RY-1025 280 -- 280 3.6 1.5

Single-family residence RY-1009 374 504 393 4.6 4.7

RY-1003 242 -- 242 3.3 0.85

RY-1004 284 -- 284 3.6 1.5

RY-1011 251 -- 251 3.3 1.0

RY-1012 155 -- 155 2.5 0.15

RS-0189 174 191 176 2.7 0.25

RS-0190 540 191 489 5.3 9.1

RS-0191 214 191 211 3.0 0.50

RS-0206 338 180 315 3.9 2.2

RS-0207 342 180 318 3.9 2.2

RS-0208 196 180 193 2.8 0.36

Single-family residence RS-0254 300 665 353 4.2 3.3

Single-family residence RS-0114 417 459 423 4.8 5.9

RY-1017 209 -- 209 3.0 0.48

RY-1018 416 -- 416 4.7 5.6

Single-family residence RY-1015 166 138 162 2.5 0.20

Single-family residence RY-1016 119 203 131 2.3 0.076

RS-0022 189 302 205 2.9 0.45

RS-0026 170 302 189 2.8 0.33

Single-family residence RS-0141 914 980 924 8.5 37

RS-0294 184 242 193 2.8 0.36

RS-0295 33 242 64 1.6 0.0050

Single-family residence RS-0276 622 707 634 6.6 18

Single-family residence RY-1008 293 -- 293 3.7 1.7

Single-family residence RY-1010 290 585 333 4.0 2.7

Duplex RY-1013 1,146 530 1,057 9.4 45

Single-family residence RS-0232 262 604 311 3.9 2.1

Duplex RY-1013 1,146 2,017 1,272 10.8 57

Duplex RY-1014 778 1,094 824 7.8 30

Duplex RY-1014 778 592 751 7.3 25

Single-family residence RS-0245 576 217 524 5.6 11

RS-0240 930 978 937 8.6 38

RS-0241 683 978 726 7.1 24

Single-family residence RS-0239 322 250 312 3.9 2.2

Single-family residence RS-0264 381 357 378 4.4 4.2

Single-family residence RS-0242 556 359 527 5.6 11

Single-family residence RS-0266 328 309 325 4.0 2.5

Single-family residence RS-0265 167 222 175 2.7 0.24

Single-family residence RS-0251 198 230 203 2.9 0.43

Single-family residence RS-0262 731 776 738 7.2 25

Single-family residence RS-0243 522 386 503 5.4 9.8

RS-0256 210 350 230 3.2 0.70

RS-0323 155 350 183 2.7 0.29

Single-family residence RS-0341 519 419 504 5.5 9.9

Single-family residence RS-0249 795 618 769 7.5 27

RS-0257 264 433 289 3.7 1.7

RS-0258 291 433 311 3.9 2.1

Single-family residence RS-0308 1,030 675 978 8.9 40

RS-0313 257 817 338 4.1 2.9

RS-0321 206 817 295 3.7 1.8

RS-0322 491 817 538 5.7 12

TABLE 8A DETERMINISTIC IEUBK MODEL RESULTS SUMMARY OU 3 RESIDENTIAL YARD AND CRAWLSPACE 

AREAS (2 DAYS PER WEEK EXPOSURE FREQUENCY)

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Single-family residence

Vacant lot

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Page 1 of 3

034544
Address Key Property Description Sample ID a

Highest Near Surface 

Composite Yard Soil 

Concentration 

(0-1 inch or 

0-6 inches bgs) 

(mg/kg)

Composite 

Crawlspace Soil 

Concentration 

(mg/kg)

Time-Weighted 

Average (TWA) 

Soil Lead 

Concentrationb

(mg/kg) 

Geometric 

Mean

Blood-Lead 

Level c

(μg/dL)

Percent 

Above d

TABLE 8A DETERMINISTIC IEUBK MODEL RESULTS SUMMARY OU 3 RESIDENTIAL YARD AND CRAWLSPACE 

AREAS (2 DAYS PER WEEK EXPOSURE FREQUENCY)

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

RY-1027 532 -- 532 5.7 11

RY-1028 177 -- 177 2.7 0.25

Single-family residence RS-0316 370 528 393 4.6 4.7

Single-family residence RS-0261 197 829 288 3.7 1.6

RS-0312 396 827 458 5.1 7.5

RS-0314 438 827 495 5.4 9.3

RS-0315 359 827 427 4.8 6.1

RY-1019 143 -- 143 2.4 0.11

RY-1020 289 -- 289 3.7 1.7

RS-0318 132 332 161 2.5 0.17

RS-0319 390 332 381 4.5 4.3

RS-0271 269 215 261 3.4 1.1

RS-0272 259 215 253 3.4 1.0

RS-0277 193 15 167 2.6 0.20

RS-0278 343 15 295 3.7 1.8

RS-0281 1,240 22 1,063 9.5 45

RS-0282 319 22 276 3.6 1.4

Single-family residence RS-0145 253 699 317 3.9 2.3

Single-family residence RS-0157 175 585 235 3.2 0.76

Single-family residence RS-0122 244 389 265 3.5 1.2

RY-1021 185 -- 185 2.7 0.30

RY-1022 81 -- 81 1.8 0.012

RY-1023 130 -- 130 2.2 0.074

RY-1024 143 -- 143 2.4 0.10

RS-0089 255 759 328 4.0 2.6

RS-0090 188 759 271 3.5 1.3

RS-0091 363 759 420 4.8 5.8

RS-0180 149 336 176 2.7 0.25

RS-0181 379 336 372 4.4 3.9

RS-0182 756 336 695 6.9 22

RS-0192 811 336 742 7.3 25

Single-family residence RS-0170 240 286 247 3.3 0.92

RS-0178 140 172 144 2.4 0.11

RS-0179 252 172 240 3.2 0.83

RS-0147 926 820 911 8.5 36

RS-0148 1,040 820 1,008 9.1 42

RS-0149 407 820 466 5.2 7.9

RS-0128 187 50 167 2.6 0.20

RS-0129 250 50 221 3.1 0.60

RS-0126 275 144 256 3.4 1.1

RS-0127 240 144 226 3.1 0.66

Single-family residence RS-0162 383 238 362 4.3 3.6

Single-family residence RS-0248 424 375 417 4.8 5.7

RY-1000 320 -- 320 3.9 2.4

RY-1001 234 -- 234 3.2 0.75

RY-1002 85 -- 85 1.8 0.015

8.7

Mean Percentage Above - Only Houses with Crawlspaces 10 e 

Mean Percentage Above - All OU 3 Data e 

Single-family residence

Vacant lot

Vacant lot

Vacant lot

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Vacant lot

Vacant lot

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Page 2 of 3

034545
Address Key Property Description Sample ID a

Highest Near Surface 

Composite Yard Soil 

Concentration 

(0-1 inch or 

0-6 inches bgs) 

(mg/kg)

Composite 

Crawlspace Soil 

Concentration 

(mg/kg)

Time-Weighted 

Average (TWA) 

Soil Lead 

Concentrationb

(mg/kg) 

Geometric 

Mean

Blood-Lead 

Level c

(μg/dL)

Percent 

Above d

TABLE 8A DETERMINISTIC IEUBK MODEL RESULTS SUMMARY OU 3 RESIDENTIAL YARD AND CRAWLSPACE 

AREAS (2 DAYS PER WEEK EXPOSURE FREQUENCY)

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Notes:

a

b

c

d

e The percent of children in the neighborhood that would have a blood-lead level exceeding the lead level of concern (10 μg/dL).

-- = not sampled

bgs = below ground surface

EPA = U.S. Environmental Protection Agency

IEUBK = Integrated Exposure and Uptake Biokinetic

mg/kg = milligram(s) per kilogram

μg/dL = microgram(s) per deciliter

Geometric mean blood-lead level for a child calculated over 6 to 84 months (or 0 to 7 years); the blood-lead level was determined using the IEUBK 

Model for Lead in Children (EPA 2003b). The measured soil concentration was used as the model input. The data set was limited to residential 

properties only and censored for duplicate results.

The percentage of exposed children that would have a blood-lead level exceeding the lead level of concern (10 μg/dL). Grey shaded cells denote 

locations where the estimated percentage of children predicted to have a blood-lead level greater than 10 μg/dL exceeded 5 percent. Four of these 

locations do not have a yard concentrations above the OU 3 clean-up goal of 463 mg/kg. 

The highest near surface soil composite lead sample from the 0 to 1-inch or 0 to 6-inch depth interval. The background concentration for lead in soil (0 

to 0.08 foot bgs) is 150.5 mg/kg; using the background value was considered more protective than the clean fill concentration of 5 mg/kg lead used 

during previous removal actions.

Figure A-1 of Appendix A presents location IDs. Table A-1 of Appendix A presents a comprehensive cross-reference of sample location IDs and 

sample numbers.

Page 3 of 3

034546
Address Key Property Description Sample ID b

Highest Near Surface 

Composite Yard Soil 

Concentration 

(0-1 inch or 

0-6 inches bgs) 

(mg/kg)

Composite 

Crawlspace Soil 

Concentration 

(mg/kg)

Time-Weighted 

Average (TWA) 

Soil Lead 

Concentration c

(mg/kg) 

Geometric Mean

Blood-Lead 

Level d

(μg/dL)

Percent 

Above e

Single-family residence RY-1005 150 -- 150 2.4 0.10

Single-family residence RS-0326 150 693 229 3.1 0.70

Single-family residence RY-1006 150 1,185 300 3.8 1.9

Single-family residence RY-1007 150 1,166 297 3.7 1.8

Single-family residence RY-1026 256 -- 256 3.4 1.1

Single-family residence RY-1025 280 -- 280 3.6 1.5

Single-family residence RY-1009 374 504 393 4.6 4.7

RY-1003 242 -- 242 3.3 0.85

RY-1004 284 -- 284 3.6 1.5

RY-1011 251 -- 251 3.3 0.98

RY-1012 155 -- 155 2.5 0.15

RS-0189 174 191 176 2.7 0.25

RS-0190 150 191 156 2.5 0.20

RS-0191 214 191 211 3.0 0.50

RS-0206 338 180 315 3.9 2.2

RS-0207 342 180 318 3.9 2.2

RS-0208 196 180 193 2.8 0.36

Single-family residence RS-0254 300 665 353 4.2 3.3

Single-family residence RS-0114 417 459 423 4.8 5.9

RY-1017 209 -- 209 3.0 0.48

RY-1018 416 -- 416 4.7 5.6

Single-family residence RY-1015 166 138 162 2.5 0.20

Single-family residence RY-1016 119 203 131 2.3 0.076

RS-0022 189 302 205 2.9 0.45

RS-0026 170 302 189 2.8 0.33

Single-family residence RS-0141 150 980 270 3.5 1.3

RS-0294 184 242 193 2.8 0.36

RS-0295 33 242 64 1.6 0.0050

Single-family residence RS-0276 150 707 231 3.2 0.70

Single-family residence RY-1008 293 -- 293 3.7 1.7

Single-family residence RY-1010 290 585 333 4.0 2.7

Duplex RY-1013 150 530 205 2.9 0.50

Single-family residence RS-0232 262 604 311 3.9 2.1

Duplex RY-1013 150 2,017 421 4.8 5.8

Duplex RY-1014 150 1,094 287 3.7 1.6

Duplex RY-1014 150 592 214 3.0 0.50

Single-family residence RS-0245 150 217 160 2.5 0.20

RS-0240 150 978 270 3.5 1.3

RS-0241 150 978 270 3.5 1.3

Single-family residence RS-0239 322 250 312 3.9 2.2

Single-family residence RS-0264 381 357 378 4.4 4.2

Single-family residence RS-0242 150 359 180 2.7 0.30

Single-family residence RS-0266 328 309 325 4.0 2.5

Single-family residence RS-0265 167 222 175 2.7 0.24

Single-family residence RS-0251 198 230 203 2.9 0.43

Single-family residence RS-0262 150 776 241 3.3 0.80

Single-family residence RS-0243 150 386 184 2.7 0.30

RS-0256 210 350 230 3.2 0.70

RS-0323 155 350 183 2.7 0.29

Single-family residence RS-0341 150 419 189 2.8 0.30

Single-family residence RS-0249 150 618 218 3.0 0.60

RS-0257 264 433 289 3.7 1.7

RS-0258 291 433 311 3.9 2.1

Single-family residence RS-0308 150 675 226 3.1 0.70

RS-0313 257 817 338 4.1 2.9

RS-0321 206 817 295 3.7 1.8

RS-0322 150 817 247 3.3 0.90

RY-1027 150 -- 150 2.4 0.10

RY-1028 177 -- 177 2.7 0.25

Single-family residence RS-0316 370 528 393 4.6 4.7

Single-family residence RS-0261 197 829 288 3.7 1.6

RS-0312 396 827 458 5.1 7.5

RS-0314 438 827 495 5.4 9.3

TABLE 8B DETERMINISTIC IEUBK MODEL RESULTS SUMMARY OU 3 RESIDENTIAL YARD AND CRAWLSPACE 

AREAS AFTER SCHEDULED REMOVAL ACTIONa (2 DAYS PER WEEK EXPOSURE FREQUENCY)

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Single-family residence

Vacant lot

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Vacant lot

Single-family residence

Page 1 of 3

034547
Address Key Property Description Sample ID b

Highest Near Surface 

Composite Yard Soil 

Concentration 

(0-1 inch or 

0-6 inches bgs) 

(mg/kg)

Composite 

Crawlspace Soil 

Concentration 

(mg/kg)

Time-Weighted 

Average (TWA) 

Soil Lead 

Concentration c

(mg/kg) 

Geometric Mean

Blood-Lead 

Level d

(μg/dL)

Percent 

Above e

TABLE 8B DETERMINISTIC IEUBK MODEL RESULTS SUMMARY OU 3 RESIDENTIAL YARD AND CRAWLSPACE 

AREAS AFTER SCHEDULED REMOVAL ACTIONa (2 DAYS PER WEEK EXPOSURE FREQUENCY)

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

RS-0315 359 827 427 4.8 6.1

RY-1019 143 -- 143 2.4 0.11

RY-1020 289 -- 289 3.7 1.7

RS-0318 132 332 161 2.5 0.17

RS-0319 390 332 381 4.5 4.3

RS-0271 269 215 261 3.4 1.1

RS-0272 259 215 253 3.4 1.0

RS-0277 193 15 167 2.6 0.20

RS-0278 343 15 295 3.7 1.8

RS-0281 150 22 131 2.3 0.10

RS-0282 319 22 276 3.6 1.4

Single-family residence RS-0145 253 699 317 3.9 2.3

Single-family residence RS-0157 175 585 235 3.2 0.76

Single-family residence RS-0122 244 389 265 3.5 1.2

RY-1021 185 -- 185 2.7 0.30

RY-1022 81 -- 81 1.8 0.012

RY-1023 130 -- 130 2.2 0.074

RY-1024 143 -- 143 2.4 0.10

RS-0089 255 759 328 4.0 2.6

RS-0090 188 759 271 3.5 1.3

RS-0091 363 759 420 4.8 5.8

RS-0180 149 336 176 2.7 0.25

RS-0181 379 336 372 4.4 3.9

RS-0182 150 336 177 2.7 0.30

RS-0192 150 336 177 2.7 0.30

Single-family residence RS-0170 240 286 247 3.3 0.92

RS-0178 140 172 144 2.4 0.11

RS-0179 252 172 240 3.2 0.83

RS-0147 150 820 247 3.3 0.90

RS-0148 150 820 247 3.3 0.90

RS-0149 407 820 466 5.2 7.9

RS-0128 187 50 167 2.6 0.20

RS-0129 250 50 221 3.1 0.60

RS-0126 275 144 256 3.4 1.1

RS-0127 240 144 226 3.1 0.66

Single-family residence RS-0162 383 238 362 4.3 3.6

Single-family residence RS-0248 424 375 417 4.8 5.7

RY-1000 320 -- 320 3.9 2.4

RY-1001 234 -- 234 3.2 0.75

RY-1002 85 -- 85 1.8 0.015

1.6

1.8

Vacant lot

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Vacant lot

Vacant lot

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Single-family residence

Vacant lot

Mean Percentage Above - All OU 3 Data f 

Mean Percentage Above - Only Houses with Crawlspaces f 

Page 2 of 3

034548
Address Key Property Description Sample ID b

Highest Near Surface 

Composite Yard Soil 

Concentration 

(0-1 inch or 

0-6 inches bgs) 

(mg/kg)

Composite 

Crawlspace Soil 

Concentration 

(mg/kg)

Time-Weighted 

Average (TWA) 

Soil Lead 

Concentration c

(mg/kg) 

Geometric Mean

Blood-Lead 

Level d

(μg/dL)

Percent 

Above e

TABLE 8B DETERMINISTIC IEUBK MODEL RESULTS SUMMARY OU 3 RESIDENTIAL YARD AND CRAWLSPACE 

AREAS AFTER SCHEDULED REMOVAL ACTIONa (2 DAYS PER WEEK EXPOSURE FREQUENCY)

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Notes:

a

b

c

d

e

f The percent of children in the neighborhood that would have a blood-lead level exceeding the lead level of concern (10 μg/dL).

-- = not sampled

bgs = below ground surface

EPA = U.S. Environmental Protection Agency

IEUBK = Integrated Exposure and Uptake Biokinetic

mg/kg = milligram(s) per kilogram

μg/dL = microgram(s) per deciliter

Geometric mean blood-lead level for a child calculated over 6 to 84 months (or 0 to 7 years); the blood-lead level was determined using the IEUBK Model for 

Lead in Children (EPA 2003b). The measured soil concentration was used as the model input. The data set was limited to residential properties only and 

censored for duplicate results.

The percentage of exposed children that would have a blood-lead level exceeding the lead level of concern (10 μg/dL). Grey shaded cells denote locations 

where the estimated percentage of children predicted to have a blood-lead level greater than 10 μg/dL exceeded 5 percent. Four of these locations do not have a 

yard concentrations above the OU 3 clean-up goal of 463 mg/kg.

Figure A-1 of Appendix A presents location IDs. Table A-1 of Appendix A presents a comprehensive cross-reference of sample location IDs and sample 

numbers.

The highest near surface soil composite lead sample from the 0 to 1-inch or 0 to 6-inch depth interval. The background concentration for lead in soil (0 to 0.08 

foot bgs) is 150.5 mg/kg; using the background value was considered more protective than the clean fill concentration of 5 mg/kg lead used during previous 

removal actions.

Scheduled removal of yard soil with concentrations above the OU 3 clean-up goal of 463 mg/kg and replaced with clean backfill having a lead concentration of 

approximately 5 mg/kg. The conservative value of 150 mg/kg used in these calculations represents the background lead concentration for the Study Area. 

Shaded cells denote locations where the yard concentration was replaced by the background lead concentration for the study area (150 mg/kg).

Page 3 of 3

034549
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL 

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless 0.14 0.29 0.43 0.14 0.29 

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 Unitless 0.5 0.5 0.5 0.5 0.5 EFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless 0.86 0.71 0.57 0.86 0.71 

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless 0.5 0.5 0.5 0.5 0.5 

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for mg/kg N/A N/A N/A 1,185 1,185 

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kg 574 574 574 963 963 PbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg 5.7E+02 5.7E+02 5.7E+02 9.8E+02 9.9E+0

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

Greg001 Greg00

RY-1005 RY-100

Page 1 of 7

034550
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL 

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 UnitlessEFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for 02 mg/kg

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kgPbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

0.14 0.29 0.43 0.14 0.29 

0.5 0.5 0.5 0.5 0.5 

0.86 0.71 0.57 0.86 0.71 

0.5 0.5 0.5 0.5 0.5 

504 504 504 N/A N/A 374 374 374 284 284 

3.8E+02 3.9E+02 4.0E+02 2.8E+02 2.8E+0

RY-1009 RY-100

Brin004 Capr00

Page 2 of 7

034551
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL 

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 UnitlessEFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for mg/kg

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kgPbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

0.14 0.29 0.43 0.14 0.29 

0.5 0.5 0.5 0.5 0.5 

0.86 0.71 0.57 0.86 0.71 

0.5 0.5 0.5 0.5 0.5 

N/A N/A N/A N/A N/A 

209 209 209 416 416 

2.1E+02 2.1E+02 2.1E+02 4.2E+02 4.2E+0

RY-1017 RY-101

Capr010 Capr01

Page 3 of 7

034552
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL 

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 UnitlessEFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for mg/kg

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kgPbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

0.14 0.29 0.43 0.14 0.29 

0.5 0.5 0.5 0.5 0.5 

0.86 0.71 0.57 0.86 0.71 

0.5 0.5 0.5 0.5 0.5 

585 585 585 530 530 290 290 290 1,146 1,146 

3.1E+02 3.3E+02 3.5E+02 1.1E+03 1.1E+0

RY-1010 RY-101

Prov003 Mark00

Page 4 of 7

034553
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL 

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 UnitlessEFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for mg/kg

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kgPbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

0.14 0.29 0.43 0.14 0.29 

0.5 0.5 0.5 0.5 0.5 

0.86 0.71 0.57 0.86 0.71 

0.5 0.5 0.5 0.5 0.5 

N/A N/A N/A N/A N/A 

211 211 211 289 289 

2.1E+02 2.1E+02 2.1E+02 2.9E+02 2.9E+0

RY-1019 RY-102

Mark013 Mark01

Page 5 of 7

034554
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SO

MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 UnitlessEFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for mg/kg

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kgPbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

0.14 0.29 0.43 0.14 0.

0.5 0.5 0.5 0.5 0

0.86 0.71 0.57 0.86 0.

0.5 0.5 0.5 0.5 0

N/A N/A N/A N/A N

143 143 143 320 3

1.4E+02 1.4E+02 1.4E+02 3.2E+02 3.2E

RY-1024 RY-

Hare017 McL

Page 6 of 7

034555
TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDEN

MANY DIVERSIFIED INTERESTS OPERABLE U

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 UnitlessEFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless

PbSCrawlspace Composite Crawlspace Soil Concentration e.g. 1,185 mg/kg for mg/kg

PbSYard Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches) e.g. 963 mg/kg for mg/kgPbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg for mg/kg

Notes:Equation : 

Parameter Description Example Parameter / Calculation Units

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it inside their residence.

 PbSWeighted = EFCrawlspace x [(fCrawlspace x PbSCrawlspace) + (fYard x PbSYard)] + (EFYard x PbSYard)

0.43

0.125

0.57

0.875

443766

7.5E+02

rvey)

Page 7 of 7

034556
MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Parameter Description Example Parameter / Calculation Units

EFCrawlspace Crawlspace Exposure Frequency 1 Day Per Week (7 Days) 1 Day / 7 Days = 0.14 Unitless 0.14 0.14 0.14 0.14 

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 Unitless 0.125 0.25 0.375 0.5 EFYard Yard Exposure Frequency (1 - EFCrawlspace) 6 Days Per Week (7 Days) 6 Day / 7 Days = 0.86 (1 - EFCrawlspace) Unitless 0.86 0.86 0.86 0.86 

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless 0.875 0.75 0.625 0.5 

PbSYard

Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches)

289 mg/kg (Average for OU 2 and OU 3) mg/kg 289 289 289 289 

PbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration 463 mg/kg is Soil Clean-Up Level mg/kg 463 463 463 463 

PbSCrawlspace Composite Crawlspace Soil Concentration Calculated Soil Lead Preliminary Remediation Goal for Crawlspace mg/kg 1.0E+04 5.2E+03 3.5E+03 2.7E+03 2

Notes:Equation : 

TWA Soil Lead Concentr

Variable Fractio

PbSCrawlspace = PbSWeighted - PbSYard x [(fYard x EFCrawlspace) + EFYard] / EFCrawlspace x fCrawlspace

TABLE 10 DETERMINISTIC CRAWLSPACE PRELIMINARY REMEDIATION GOALS FOR OU 3 RESIDENTIAL Y

(1 DAY PER WEEK EXPOSURE)

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest ooutdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are a

Page 1 of 1

034557
MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Parameter Description Example Parameter / Calculation Units

EFCrawlspace Crawlspace Exposure Frequency 2 Days Per Week (7 Days) 2 Days / 7 Days = 0.29 Unitless 0.29 0.29 0.29 0.29 

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 Unitless 0.125 0.25 0.375 0.5 EFYard Yard Exposure Frequency (1 - EFCrawlspace) 5 Days Per Week (7 Days) 5 Days / 7 Days = 0.71 (1 - EFCrawlspace) Unitless 0.71 0.71 0.71 0.71 

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless 0.875 0.75 0.625 0.5 

PbSYard

Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches)

289 mg/kg (Average for OU 2 and OU 3) mg/kg 289 289 289 289 

PbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration 463 mg/kg is Soil Clean-Up Level mg/kg 463 463 463 463 

PbSCrawlspace Composite Crawlspace Soil Concentration Calculated Soil Lead Preliminary Remediation Goal for Crawlspace mg/kg 5.2E+03 2.7E+03 1.9E+03 1.5E+03 1

Notes:Equation : 

TWA Soil Lead Concentr

Variable Fractio

PbSCrawlspace = PbSWeighted - PbSYard x [(fYard x EFCrawlspace) + EFYard] / EFCrawlspace x fCrawlspace

TABLE 11 DETERMINISTIC CRAWLSPACE PRELIMINARY REMEDIATION GOALS FOR OU 3 RESIDENTIAL Y

(2 DAYS PER WEEK EXPOSURE)

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest ooutdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are a

Page 1 of 1

034558
MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Parameter Description Example Parameter / Calculation Units

EFCrawlspace Crawlspace Exposure Frequency 3 Days Per Week (7 Days) 3 Days / 7 Days = 0.43 Unitless 0.43 0.43 0.43 0.43 

fCrawlspace Crawlspace Fraction of Time 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 Unitless 0.125 0.25 0.375 0.5 EFYard Yard Exposure Frequency (1 - EFCrawlspace) 4 Days Per Week (7 Days) 4 Days / 7 Days = 0.57 (1 - EFCrawlspace) Unitless 0.57 0.57 0.57 0.57 

fYard Yard Fraction of Time (1 - fCrawlspace) 2 Hours Per 4 Hour Day 2 Hours / 4 Hours = 0.5 (1 - fCrawlspace) Unitless 0.875 0.75 0.625 0.5 

PbSYard

Highest Near Surface Composite Yard Soil Concentration (0 to 1-inch or 0 to 6-inches)

289 mg/kg (Average for OU 2 and OU 3) mg/kg 289 289 289 289 

PbSWeighted Time-Weighted Average (TWA) Soil Lead Concentration 463 mg/kg is Soil Clean-Up Level mg/kg 463 463 463 463 

PbSCrawlspace Composite Crawlspace Soil Concentration Calculated Soil Lead Preliminary Remediation Goal for Crawlspace mg/kg 3.5E+03 1.9E+03 1.4E+03 1.1E+03 9

Notes:Equation : 

TWA Soil Lead Concentr

Variable Fractio

PbSCrawlspace = PbSWeighted - PbSYard x [(fYard x EFCrawlspace) + EFYard] / EFCrawlspace x fCrawlspace

TABLE 12 DETERMINISTIC CRAWLSPACE PRELIMINARY REMEDIATION GOALS FOR OU 3 RESIDENTIAL Y

(3 DAYS PER WEEK EXPOSURE)

Children are assumed to have exposure to crawlspace soil each day for a total of 52 days spread evenly over 1 year, 6 months, or 4 months (i.e. 1, 2, or 3 days per week respectively). The rest ooutdoors on the front or backyard. Children between the age of 2 and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are a

Page 1 of 1

034559
TABLE 13

EXPOSURE POINT CONCENTRATION FORECAST

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Model Run 1 - OU 2 and OU 3 Lead Data (mg/kg) Model Run 2 - OU 2 and OU 3 Lead Data 

10th Percentile 50th Percentile 75th Percentile 90th Percentile 10th Percentile 50th Percentile 75th Percenti

Annual 202 398 587 854 162 267 348 

Winter 212 413 595 823 171 288 382 

Spring 194 394 580 832 159 260 337 Summer 198 392 577 847 162 262 344 Fall 201 401 587 836 162 267 351 

Notes:These data results reflect 10,000 iterations for the forecast named Concentration for Model Input.mg/kg = Milligram(s) per kilogramOU = Operable UnitIn general, lower percentiles reflect lower exposure times and lower lead concentrations in soil.ScenarioEPCs are a function of time spent outside; lower EPCs were found, as expected, in the colder months. The annual average is reflective of exposure blood-lead model exposure concentration input assumes uniform exposure throughout the year. Thus the annual scenario would be the input for IEconcentration.RA = Scheduled removal of yard soil with concentrations above the OU 3 clean-up goal of 463 mg/kg and replaced with background lead concentrthe Study Area; using the background value was considered more protective than the clean fill concentration of 5 mg/kg lead used during previous 

034560
TABLE 14

CRAWLSPACE CLEAN-UP GOAL FORECAST

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Model Run 1 - OU 2 and OU 3 Lead Data (mg/kg) Model Run 2 - OU 2 and OU 3 Lead Da

10th Percentile 50th Percentile 75th Percentile 90th Percentile 10th Percentile 50th Percentile 75th Percenti

Annual 0 840 1,585 2,466 742 1,596 2,289 

Winter 0 675 1,051 1,596 646 1,032 1,442 Spring 0 895 1,812 3,011 762 1,839 2,756 Summer 0 905 1,798 2,811 751 1,730 2,632 Fall 0 752 1,554 2,731 673 1,535 2,490 Notes:These data results reflect 10,000 iterations.mg/kg = Milligram(s) per kilogram; OU = Operable UnitIn general, lower percentiles reflect higher exposure times and higher lead concentrations in soil.

Scenario

Model Run 1 10th percentile results were negative based on an artifact of the equation (occuring when yard concentrations were over the 463 mg

and are reflected in this table as effectly zero.RA = Scheduled removal of yard soil with concentrations above the OU 3 clean-up goal of 463 mg/kg and replaced with background lead concethe Study Area; using the background value was considered more protective than the clean fill concentration of 5 mg/kg lead used during previou

034561
TABLE 15 SUMMARY OF PROPERTIES ADDRESSED DURING EPA AND TNRCC REMOVAL ACTIONS (1999 - 2009)

MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3

Property Type

Within Modeled Air 

Deposition Area and 

East Blower Area

Outside of Modeled 

Air Deposition Area 

and East Blower Area Total

Within Modeled Air 

Deposition Area and 

East Blower Area

Outside of Modeled 

Air Deposition Area 

and East Blower 

Area Total

Within Modeled Air 

Deposition Area and 

East Blower Area

Outside of Modeled 

Air Deposition Area 

and East Blower 

Area Total

Within M

Depositio

East Bl

Residential 40 29 69 37 0 37 5 0 5 

Vacant lot 10 10 20 16 0 16 1 0 1 Public housing 0 0 0 1 0 1 0 0 0 

Commercial/industrial 0 0 0 1 0 1 0 0 0 

Public use 0 0 0 1 0 1 0 0 0 

Church 0 0 0 3 0 3 0 0 0 

School 0 0 0 1 0 1 0 0 0 

Daycare center 0 0 0 0 0 0 0 0 0 

TOTAL 50 39 89 60 0 60 6 0 6 

Notes:EPA U.S. Environmental Protection AgencyOU Operable UnitRI Remedial InvestigationTNRCC Texas Natural Resource Conservation Commission (now known as the Texas Commission on Environmental Quality)

TO

S

Summary of Properties Remediated during TNRCC 

Removal Action 

(1999)

Summary of OU 2 Properties Remediated during 

Previous EPA Removal Actions (2003 - 2006)

Modeled Air Deposition Area is defined as the predicted impact area corresponding to lead concentrations ranging greater than 400 mg/kg (bound by the 0.8 

Summary of OU 3 Properties Scheduled for Upcoming 

EPA Removal Action (2009)

034562
 

Figures 

034563
s s S t

0.8 g/m

2- year

400 mg/kg

2009-04-09 f:\federal\epa\rac ii\0026-mdi ri\mdi_gis\mxd\ri-fig02.mxd EA-Dallas jschwertz

T e x a s

G u l f 

o f 

M e x i c o

Austin

Houston

San Antonio

Corpus Christi

Site Location

McAllen

Pasadena

Brownsville

§ ̈¦10 § ̈¦35

§ ̈¦45

LA

TX

I

Legend

0 490

Feet

Figure 2.

Summary of Previous EPA 

and TCEQ Activities

MDI Superfund Site

Houston, Texas

Isopleth for the Rate of Deposition 

(g/m

2

-year) Based on Air Quality 

Impact Modeling Results; 

Equates to Predicted Area of 

400 mg/kg Lead/Soil Concentration

Property determined to no longer 

pose a risk by virtue of sampling, 

removal action or risk assessment

Commercial/Industrial Property or 

Utility Easement (not sampled)

Property not sampled due to 

denied access or inability to 

contact/locate owner

Background Study Area

MDI Site (OU1)

TCEQ Removal Action

EPA Removal Action

Property was commercial/industrial 

during previous OU 1/OU 2 RI/FS; 

only recently became residential

Modeled Air Deposition Area

East Blower Area

Study Area (OU2 and OU3)

Prepared 

For:

Prepared 

By:

034564
B

0.8 g/m

2- year

400 mg/kg

2009-04-09 f:\federal\epa\rac ii\0026-mdi ri\mdi_gis\mxd\ri-fig03.mxd EA-Dallas jschwertz

T e x a s

G u l f 

o f 

M e x i c o

Austin

Houston

San Antonio

Corpus Christi

Site Location

McAllen

Pasadena

Brownsville

§ ̈¦10 § ̈¦35

§ ̈¦45

LA

TX

I

0 525

Feet

Prepared 

For:

Prepared 

By:

Figure 3. 

OU3 Residential Yard 

Sampling Summary

MDI Superfund Site

Houston, Texas

Legend

Isopleth for the Rate of Deposition 

(g/m

2

-year) Based on Air Quality 

Impact Modeling Results; 

Equates to Predicted Area of 

400 mg/kg Lead/Soil Concentration

Background Study Area

OU 3 Residential Yards

Residential Yard Sample Location

Modeled Air Deposition Area

East Blower Area

Study Area (OU2 and OU3)

034565
034566
034567
35	Polygon	965281	0081560000011	 	 	0	T

80	Polygon	968481	0562330000004	 	 	0	G

86	Polygon	1296400	0090120000006	15	6	

68	Polygon	965353	0590090020013	 	 	0	C

53	Polygon	965588	0511790090019	 	 	0	F

8	Polygon	965561	0562330000011	 	 	0	TE

16	Polygon	965562	0562330000010	 	 	0	M

12	Polygon	965531	0562320000021	 	 	0	A

13	Polygon	965533	0562320000022	 	 	0	G

83	Polygon	965524	0562320000016	 	 	0	H

46	Polygon	967718	0221890000032	 	 	0	B

47	Polygon	968559	0562330000027	 	 	0	C

82	Polygon	1061047	0421500000110	 	 	0	

38	Polygon	967717	0221890000043	 	 	0	M

11	Polygon	965535	0562310000012	 	 	0	E

60	Polygon	1074171	0071310000002	 	 	0	

43	Polygon	1061050	0421500000125	 	 	0	

56	Polygon	965265	0421500000410	 	 	0	R

57	Polygon	965539	0562310000010	 	 	0	H

17	Polygon	965594	0511790090021	 	 	0	H

33	Polygon	965350	0590090020019	 	 	0	C

42	Polygon	1074169	0071310000007	 	 	0	

20	Polygon	983053	0351240000012	 	 	0	H

21	Polygon	967197	0610230090002	 	 	0	J

37	Polygon	965532	0562320000005	 	 	0	P

92	Polygon	1519694	0090080000014	11	 	0

93	Polygon	1519692	0090080000013	 	 	0	

58	Polygon	967736	0221900000008	 	 	0	B

84	Polygon	1061109	0090110000003	 	 	0	

64	Polygon	965250	0081540000005	 	 	0	E

36	Polygon	965309	0590090010010	 	 	0	C

66	Polygon	1061033	0350090000007	 	 	0	

55	Polygon	965171	0351330000001	 	 	0	T

50	Polygon	965526	0562320000017	 	 	0	S

10	Polygon	965766	0511780080009	 	 	0	C

40	Polygon	965174	0351330000009	 	 	0	R

76	Polygon	967735	0221900000012	 	 	0	M

34	Polygon	965559	0562330000014	 	 	0	J

41	Polygon	1074168	0071310000009	 	 	0	

71	Polygon	1061132	0090090000004	 	 	0	

81	Polygon	983554	0090050000014	 	 	0	C

6	Polygon	965310	0590090010011	 	 	0	CO

5	Polygon	965316	0590090010003	 	 	0	CO

4	Polygon	965315	0590090010004	 	 	0	CO

77	Polygon	965520	0562320000013	 	 	0	S

62	Polygon	965667	0511790100031	 	 	0	M

67	Polygon	965237	0081530000014	 	 	0	C

2	Polygon	965336	0090060000001	 	 	0	W

7	Polygon	965369	0090070000011	 	 	0	CE

3	Polygon	965368	0090070000001	 	 	0	CO

95	Polygon	1542284	1294850010001	 	1	0	

65	Polygon	965527	0562320000018	 	 	0	W

15	Polygon	965767	0511780080003	 	 	0	A

0	Polygon	965364	0090070000006	 	 	0	TD

70	Polygon	1074172	0071310000013	 	 	0	

78	Polygon	965355	0590090020001	 	 	0	C

59	Polygon	965241	0421500000385	 	 	0	T

1	Polygon	1409878	0090070000003	 	 	0	T

94	Polygon	1516549	1302230010001	1	1	0

96	Polygon	1542286	0090060000008	 	 	0	

FID	Shape *	OBJECTID	HCAD_NUM *	BLK_

4327	Polygon	1061043	0350090000002	 	 	

§ ̈¦10

§ ̈¦10

t

0.8 g/m2- year

400 mg/kg

CS-1080

386 mg/kg

CS-1023

191 mg/kg

CS-1027

759 mg/kg

CS-1022

180 mg/kg

CS-1077

336 mg/kg

CS-1031

820 mg/kg

BG-1002

600 mg/kg

BG-1011

256 mg/kg

BG-1001

749 mg/kg

CS-1028

22 mg/kg

CS-1054

265 mg/kg

CS-1029

15 mg/kg

BG-1000

344 mg/kg

CS-1058

144 mg/kg

CS-1004

332 mg/kg

CS-1045

978 mg/kg

CS-1065

592 mg/kg

CS-1074

189 mg/kg

BG-1004

296 mg/kg

CS-1076

341 mg/kg

CS-1067

443 mg/kg

CS-1061

215 mg/kg

CS-1012

776 mg/kg CS-1079

357 mg/kg

CS-1069

242 mg/kg

CS-1041

699 mg/kg

CS-1085

186 mg/kg

CS-1082

363 mg/kg

CS-1060

302 mg/kg

CS-1000

50 mg/kg

CS-1001

172 mg/kg

CS-1002

585 mg/kg

CS-1057

286 mg/kg

CS-1063

238 mg/kg

CS-1078

138 mg/kg

CS-1084

433 mg/kg

BG-1003

300 mg/kg

CS-1007

817 mg/kg

CS-1072

504 mg/kg

CS-1006

528 mg/kg

CS-1038

829 mg/kg

CS-1055

350 mg/kg

BG-1009

188 mg/kg

CS-1032

CS-1068 389 mg/kg

513 mg/kg

CS-1005

827 mg/kg

CS-1081

73 mg/kg

CS-1019

980 mg/kg

CS-1043

230 mg/kg CS-1034

217 mg/kg

CS-1036

375 mg/kg

CS-1052

585 mg/kg

CS-1021

459 mg/kg

CS-1056

249 mg/kg

CS-1003

794 mg/kg

CS-1073

591 mg/kg

CS-1015

511 mg/kg

CS-1018

604 mg/kg

CS-1040

245 mg/kg

BG-1010

246 mg/kg

CS-1020

302 mg/kg

CS-1009

618 mg/kg

CS-1047

278 mg/

CS-1013

359 mg/kg

CS-1025

1185 mg/kg

CS-1024

1166 mg/kg

CS-1049

2429 mg/kg

CS-1083

911 mg/kg

-106

452 mg/kg

CS-1064

297 mg/kg

CS-1026

693 mg/kg

BG-1007

83 mg/kg

CS-1071

222 mg/kg

BG-1008

185 mg/kg

CS-1035

203 mg/kg

CS-1053

190 mg/kg

CS-1008

675 mg/kg

CS-1010

419 mg/kg

CS-1042

309 mg/kg

CS-1011

386 mg/kg CS-1014

250 mg/kg

CS-1075

592 mg/kg

CS-1046

465 mg/k

CS-1070

530 mg/kg

CS-1051

665 mg/kg

CS-1016

1094 mg/kg

CS-1017

2017 mg/kg

CS-1037

3204 mg/kg

2009-04-09 f:\federal\epa\rac ii\0026-mdi ri\mdi_gis\mxd\ri-fig06_rev002.mxd EA-Dallas jschwertz

T e x a s

G u l f 

o f 

M e x i c o

Austin

Houston

San Antonio

Corpus Christi

Site Location

§ ̈¦10

§ ̈¦35

§ ̈¦45

TX

LA

I

0 590

Feet

Legend

Accessible Crawlspace sampled

Accessible Crawlspace not sampled

Accessible Crawlspace not sampled,

Access Granted

Isopleth for the Rate of Deposition

(g/m2

-year) Based on Air Quality

Impact Modeling Results;

Equates to Predicted Area of

400 mg/kg Lead/Soil Concentration

BackgroundStudyArea

Modeled Air Deposition Area

East Blower Area

Study Area (OU2 and OU3)

Figure 6. 

OU3 Crawlspace Sampling

Summary and Results

MDI Superfund Site

Houston, Texas

034568
B r i n g h 

C a g e 

P r e s s 

400 mg/kg

RY-1025

0-1 278.98 mg/kg

0-6 280.29 mg/kg

6-12 258.81 mg/kg

12-18 29.51 mg/kg

RY-1023

0-1 130 mg/kg

0-6 91.54 mg/kg

6-12 50.24 mg/kg

12-18 28.86 mg/kg

RY-1016

12-18 35.37 mg/kg

6-12 155 mg/kg

0-6 119.15 mg/kg

0-1 98.43 mg/kg

RY-1010

0-1 290.31 mg/kg

0-6 265.16 mg/kg

6-12 88.36 mg/kg

12-18 31.19 mg/kg

RY-1009

0-1 260.97 mg/kg

0-6 373.97 mg/kg

6-12 151.61 mg/kg

12-18 75.99 mg/kg

RY-1021

0-1 183.35 mg/kg

0-6 185.03 mg/kg

6-12 65.74 mg/kg

12-18 17.69 mg/kg

RY-1006

0-1 744.67 mg/kg

0-6 963.01 mg/kg

6-12 128.42 mg/kg

12-18 196.27 mg/kg

RY-1001

0-1 198 mg/kg

0-6 233.52 mg/kg

6-12 69.07 mg/kg

12-18 56.03 mg/kg

RY-1019

0-1 138.61 mg/kg

0-6 142.79 mg/kg

6-12 59.56 mg/kg

12-18 18.72 mg/kg

RY-1017

0-1 208.73 mg/kg

0-6 134.82 mg/kg

6-12 77.57 mg/kg

12-18 56.7 mg/kg

RY-1015

0-1 165.92 mg/kg

0-6 144.77 mg/kg

6-12 142.96 mg/kg

12-18 52.03 mg/kg

RY-1004

0-1 283.66 mg/kg

0-6 235.29 mg/kg

6-12 154.8 mg/kg

12-18 73.83 mg/kg RY-1027

0-1 329 mg/kg

0-6 532 mg/kg

6-12 121 mg/kg

12-18 16.6 mg/kg

RY-1011

0-1 84.05 mg/kg

0-6 250.63 mg/kg

6-12 131.81 mg/kg

12-18 27.03 mg/kg

RY-1013

0-1 1146.46 mg/kg

0-6 989.06 mg/kg

6-12 217.53 mg/kg

12-18 52.19 mg/kg

RY-1014

0-1 777.59 mg/kg

0-6 415.8 mg/kg

6-12 164.75 mg/kg

12-18 57.8 mg/kg

RY-1008

0-1 192.52 mg/kg

0-6 292.71 mg/kg

6-12 83.45 mg/kg

12-18 28.58 mg/kg

RY-1026

0-1 256.35 mg/kg

0-6 236.49 mg/kg

6-12 50.71 mg/kg

12-18 39.71 mg/kg

RY-1005

0-1 440.66 mg/kg

0-6 573.64 mg/kg

6-12 177.77 mg/kg

12-18 69.96 mg/kg

RY-1007

0-1 1190 mg/kg

0-6 785.72 mg/kg

6-12 136.98 mg/kg

12-18 75.46 mg/kg

RY-1000

0-1 320 mg/kg

0-6 151.39 mg/kg

6-12 116.1 mg/kg

12-18 40.11 mg/kg

RY-1002

0-1 75.44 mg/kg

0-6 84.98 mg/kg

6-12 60.87 mg/kg

12-18 22.79 mg/kg

RY-1003

0-1 241.89 mg/kg

0-6 225.06 mg/kg

6-12 38.72 mg/kg

12-18 17.52 mg/kg

RY-1012

0-1 155.11 mg/kg

0-6 92.95 mg/kg

6-12 89.62 mg/kg

12-18 50.68 mg/kg

RY-1018

0-1 415.52 mg/kg

0-6 351.8 mg/kg

6-12 47.5 mg/kg

12-18 35.93 mg/kg

RY-1020

0-1 185.05 mg/kg

0-6 211.2 mg/kg

6-12 289.02 mg/kg

12-18 31.12 mg/kg

RY-1022

0-1 80.54 mg/kg

0-6 75.67 mg/kg

6-12 58.38 mg/kg

12-18 80.95 mg/kg

RY-1024

0-1 101.93 mg/kg

0-6 143.14 mg/kg

6-12 76.61 mg/kg

12-18 43.9 mg/kg

RY-1028

0-1 79.3 mg/kg

0-6 177 mg/kg

6-12 35.5 mg/kg

12-18 20.1 mg/kg

2009-04-09 f:\federal\epa\rac ii\0026-mdi ri\mdi_gis\mxd\ri-fig07_rev002.mxd EA-Dallas jschwertz

T e x a s

G u l f 

o f 

M e x i c o

Austin

Houston

San Antonio

Corpus Christi

Site Location

§ ̈¦10 § ̈¦35

§ ̈¦45

TX

LA

I

0 350

Feet

Figure 7. 

OU3 Residential Yard

Sampling Results

MDI Superfund Site

Houston, Texas

Legend

Residential Yard Sample Location

Isopleth for the Rate of Deposition

(g/m

2

-year) Based on Air Quality

Impact Modeling Results;

Equates to Predicted Area of

400 mg/kg Lead/Soil Concentration

Modeled Air Deposition Area

East Blower Area

Study Area (OU2 and OU3)

Sample Name

0-1 (depth interval in inches) 138.61 mg/kg (Lead concentration in soil)

Red text indicates results exceeding the practical cleanup level of 

463 mg/kg Lead concentration in soil

034569

Input Parameters

Indoor Air Lead Concentration 

Outdoor Air Lead Concentration Perform Integrated Exposure 

U t k Bi Ki ti (IEUBK)

(Percentage of Outdoor) = 0.30 

(Model Default)

Air

= 0.1 μg/m3 (Model Default) Uptake Bio-Kinetic (IEUBK) Lead Modeling for Each Area Air

Time Spent Outdoors, Ventilation 

Rate, and Lung Absorption Were 

, gp

Model Defaults

Dietary Dietary Lead Intake Were Consistent with OU2 Model Defaults

Water Consumption were 

Model Defa lts IE

Lead Concentration in Drinking 

Water = 4 μg/L (Model Default)

Model Defaults Water

C Si C i

IE

of 

L

Outdoor Soil Lead Level =

Soil/Dust Ingestion Weighting Factor 

(Percent Soil) = 45 (Model Default)

Compare Site Concentration 

Against the Lead Action Level of 463 mg/kg for Each Area Greater T

Outdoor Soil Lead Level =

Area-Specific Maximum Soil 

Concentration (μg/g)

Soil

Amount of Soil/Dust Ingested Daily

Lead Action 

of 463 mg/

Amount of Soil/Dust Ingested Daily

Were Model Defaults

Mother’s Blood Lead Concentration 

Maternal

C

at Childbirth = 2.5 μg Lead per dL 

(Model Default)

No 

Alternate Alternate Lead Intake – None 

Identified (Model Default) 

Risk Management Decision 

Area Not S bject to Remedial Action if Percentage

F ti P i / T t l A ibl

Total Percent Accessible = 30% Soil, 

30% Dust, 50% Water, 50% Diet, 

and 0% Alternate (Model Defaults)

GI/Bi

Area Not Subject to Remedial Action if Percentage

of Children 6 to 84 Months (7 Years) with Predicted 

Blood Lead Levels > 10 μg/dL is Acceptable

Fraction Passive / Total Accessible 

= 0.2 ( Model Default)

GI/Bio

Half Saturation Level = 100 μg /day 

Many Diversified Interests, Inc. Superfund Site 

(Model Default)

EA Engineering, Science, and Technology, Inc. y p

Houston, Harris County, Texas

g g, , gy,

Project Number - 1434226

034571
 

Appendix A 

Access Agreements 

034572
 

Appendix B 

Summary of Qualitative Door-to-Door Surveys 

034573
 

Appendix C 

Residential Property Sketches

034574
 

Appendix D 

Analytical Data Summary Tables 

Table D-1 Analytical Data Summary – Lead in Soil (2003 – 2008) 

Table D-2 Analytical Data Summary – Residential Yard Soil (2003 – 2008) 

Table D-3 Analytical Data Summary – Residential Crawlspace Soil (2003 – 2008) 

Table D-4 Analytical Data Summary – Background Yard Soil (2003 – 2008) 

Table D-5 Analytical Data Summary – Background Crawlspace Soil (2003 – 2008) 

Table D-6 TNRCC Removal Action List (1999) 

Table D-7 Analytical Data Summary – Average In Situ Lead Concentrations in Exterior Paint 

(2008) 

Table D-8 Vertical Clearances for Accessible OU 3 Crawlspaces (2008) 

Table D-9 Residence Identifiers and Address Keys 

034575
Appendix D-9 

Residence Identifiers and Address Keys

034576
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Blanche Kelso Bruce Elementary School Bruc001

Page 1 of 9 CONFIDENTIAL INFORMATION

034577
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 2 of 9 CONFIDENTIAL INFORMATION

034578
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 3 of 9 CONFIDENTIAL INFORMATION

034579
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 4 of 9 CONFIDENTIAL INFORMATION

034580
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 5 of 9 CONFIDENTIAL INFORMATION

034581
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address

Page 6 of 9 CONFIDENTIAL INFORMATION

034582
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

3600 Providence Street

Page 7 of 9 CONFIDENTIAL INFORMATION

034583
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 8 of 9 CONFIDENTIAL INFORMATION

034584
TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 9 of 9 CONFIDENTIAL INFORMATION

034585
 

Appendix E 

Results of Statistical Analysis of Soil Data

 

034586
XRF = 0.95*Lab + 9.3

R2 = 0.93

p < 0.001

800

10001200

mg/kg)

Figure E-1 Linear Regression of Collocated XRF and Laboratory Data

0

200400600

0 200 400 600 800 1000 1200

XRF Lead (m

Laboratory Lead (mg/kg)

034587
TABLE E-1

REGRESSION ANALYSIS OF LABORATORY AND XRF LEAD DATA

MANY DIVERSIFIED INTERESTS SUPERFUND SITE OPERABLE UNIT 3

Regression Statistics

Multiple R 0.96R Square 0.93

Adjusted R Square 0.93Standard Error 58.25Observations 73Analysis of Variance

df SS MS F Significance F

Regression 1 3072510.74 3072510.74 905.56 0.000Residual 71 240898.09 3392.93Total 72 3313408.83

Coefficients Standard Error t Stat P-value Lower 95% Up

Intercept α (mg/kg) 9.30 9.89 0.94 0.35 -10.42 

Slope β 0.95 0.03 30.09 0.00 0.89 

Notes:df = degree(s) of freedomF = F-distribution variableMS = mean sum of squaresP-value = attained level of significanceR = sample correlation coefficientSS = sum of squarest Stat = Student's t variableXRF = x-ray fluorescence

034588
Figure E 2 Least Trimmed Squares (LTS) Linear Regression of Sieved and Unsieved Sample Re

2500

Figure E-2 Least Trimmed Squares (LTS) Linear Regression of Sieved and Unsieved Sample Re

Lead in Yard Samples

20001500

d (mg/kg) 

Unsieved = 1.07*Sieved ‐ 28.7R2 = 91%

p < 0.0001

1000

Unsieved Soil Lea

500

U

0

0 500 1000 1500 2000 2500

Sieved Soil Lead (mg/kg)

034589
TABLE E-2

REGRESSION ANALYSIS OF SIEVED & UNSIEVED SAMPLE RESULTS IN YARD SAMPL

MANY DIVERSIFIED INTERESTS SUPERFUND SITE OPERABLE UNIT 3

Regression Statistics

R Square 0.88Observations 28

Coefficients Standard Error Lower 95% Upper 9

Intercept α (mg/kg) -28.68 27.86 -83.28 

Slope β 1.07 0.06 0.95 

R = coefficient of determination

034590
Figure E 3 Linear Regression of Sieved and Unsieved Sample Results for Lead in Crawlspace S

2500

Figure E-3 Linear Regression of Sieved and Unsieved Sample Results for Lead in Crawlspace 

2000

Unsieved = 1 00*Sieved + 14 7

1500

d (mg/kg) 

Unsieved = 1.00 Sieved + 14.7R2 = 96%

p < 0.0001

1000

Unsieved Soil Lea

500

U

0

0 500 1000 1500 2000 2500

Sieved Soil Lead (mg/kg)

034591
Regression Statistics

R Square 0.96Observations 22

Coefficients Standard Error Lower 95% Upp

Intercept α (mg/kg) 14.73 26.26 -36.73 

Slope β 1.00 0.05 0.90 

R = coefficient of determination

REGRESSION ANALYSIS OF SIEVED & UNSIEVED SAMPLE RESULTS IN CRAWLSPACE SAM

MANY DIVERSIFIED INTERESTS SUPERFUND SITE OPERABLE UNIT 3

TABLE E-3

034592
Yard = 0.51*Crawlspace + 135

R2 = 0.31

p < 0.001

800

10001200

mg/kg)

Figure E-4 Linear Regression of Sieved Crawlspace and Sieved Yard Sample Results

0

200400600

0 200 400 600 800 1000 1200

Yard Lead (m

Crawlspace Lead (mg/kg)

034593
TABLE E-4

REGRESSION ANALYSIS OF SIEVED CRAWLSPACE AND SIEVED YARD LEAD DA

MANY DIVERSIFIED INTERESTS SUPERFUND SITE

Regression Statistics

Multiple R 0.55R Square 0.31

Adjusted R Square 0.29Standard Error 217.30Observations 56Analysis of Variance

df SS MS F Significance F

Regression 1 1127442.03 1127442.03 23.88 0.0000

Residual 54 2549790.99 47218.35Total 55 3677233.02

Coefficients Standard Error t Stat P-value Lower 95% Up

Intercept α (mg/kg) 135.46 55.07 2.46 0.02 25.06 

Slope β 0.51 0.10 4.89 0.00 0.30 

Notes:df = degree(s) of freedomF = F-distribution variableMS = mean sum of squaresP-value = attained level of significanceR = sample correlation coefficientSS = sum of squarest Stat = Student's t variable

034594
FIGURE E-5

LINEAR REGRESSION ANALYSIS OF LEAD CONCENTRATIONS FOR EXTERIOR 

PAINT AND SIEVED/UNSIEVED SOIL SAMPLES FROM BACKGROUND STUDY AREA 

MDI SUPERFUND SITE OPERABLE UNIT 3 

Lead Concentrations for Exterior Paint and Sieved Soil Samples from Background Study Area

Lead Concentrations for Exterior Paint and Unsieved Soil Samples from the Background Study Area

y = ‐0.0018x + 1.8858

R2 = 0.2057

0

0.5

1

1.5

2

2.5

0 100 200 300 400 500 600 700 800

Lead Concentration in Exterior Paint

(mg/cm2)

Lead Concentration in Crawlspace Soil (mg/kg)

y = 7E‐07x + 1.2607

R2 = 4E‐07

0

0.5

1

1.5

2

0 100 200 300 400 500 600 700 800

Exterior Paint (mg/cm2)

Crawlspace Soil (mg/kg)

034595
FIGURE E-6

LINEAR REGRESSION ANALYSIS OF LEAD CONCENTRATIONS FOR EXTERIOR 

PAINT AND SIEVED/UNSIEVED SOIL SAMPLES FROM OPERABLE UNIT 3 

MDI SUPERFUND SITE OPERABLE UNIT 3

Lead Concentrations for Exterior Paint and Sieved Soil Samples from Operable Unit 3

Lead Concentrations for Exterior Paint and Unsieved Soil Samples from Operable Unit 3

y = ‐3E‐07x + 0.4914

R2 = 3E‐08

0

1

2

3

4

5

0 500 1000 1500 2000 2500 3000 3500

Lead Concentration in Exterior Paint

(mg/cm2)

Lead Concentration in Crawlspace Soil (mg/kg)

y = ‐0.0003x + 0.6577

R2 = 0.0433

0

0.5

1

1.5

2

2.5

0 500 1000 1500 2000 2500

Exterior Paint (mg/cm2)

Crawlspace Soil (mg/kg)

034596
 

Appendix F 

Fixed Laboratory Data Packages 

Appendix F-1 EPA Region 6 Laboratory Data Package(s) 

Appendix F-2 Aerotech Environmental Laboratories/TestAmerica 

Laboratories Data Package(s) 

Appendix F-3 Accutest Laboratories-Gulf Coast Data Package(s) 

Appendix F-4 FAI Materials Testing Laboratory Data Package and Report 

Appendix F-5 Weston Solutions Backfill Material Data 

034597
 

Appendix G 

Electronic Data (on deliverable compact disc) 

Microsoft Access Database 

Photographs 

034598