# 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. 14342.26EA Project No. 14342.26 Contents, Page 1 of 2 EA Engineering, Science, and Technology, Inc. April 2009

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 FI ELD 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 .................................................................................25EA Project No. 14342.26 Contents, Page 2 of 2 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 So il 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 C ONSIDERATIONS ..................................................................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 QUALI TATIVE 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 DATAEA Project No. 14342.26 List of Figures and Tables, Page 1 of 2 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### TABLES

1 Summary of Properties (Yards) Addresse d During Previous Investigations and Removal Actions (1999 – 2006)

2 Summary of Property Access and Sa mpling for Residential Crawlspaces

3 Summary of Property Access and Sampli ng for Residential Yards and High-Access

Areas

4 Summary of Sc reening 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 Result s 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 Remova l 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 Reme diation Goals for OU 3 Residential Yard Soil Samples (1 Day per Week Exposure)

11 Deterministic Crawlspace Preliminary Reme diation 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)EA Project No. 14342.26 List of Figures and Tables, Page 2 of 2 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 Co llecting 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 ChartEA Project No. 14342.26 List of Acronyms and Abbreviations, Page 1 of 2 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### LIST OF ACRONYMS AND ABBREVIATIONS

μg/dL microgram(s) per deciliter μm micrometer(s) Agreed Order Agreed Order on C onsent 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

ft 2 

### Square foot (feet) g/m 2 

### -year gram(s) per square meter per year

GPS Global Positioning System HCAD Harris County A ppraisal District

HHRA Human Health Risk Assessment

HSP Health and Safety Plan

HUD Department of Housi ng and Urban Development

I-10 U.S. Interstate Highway 10 IEUBK Integrated Exposure Uptake Biokinetic

LTS least trimmed squares

MDI Many Diversified Interests mg/cm 2 

### 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 a nd 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 DecisionEA Project No. 14342.26 List of Acronyms and Abbreviations, Page 2 of 2 EA Engineering, Science, and Technology, Inc. April 2009



### LIST OF ACRONYMS AND ABBREVIATIONS (Continued)

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### SAP Sampling and Analysis Plan

SEM scanning electron microscopy

SOW Statement of Work SRI Superfund Redevel opment 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 Resour ce Conservati on Commission TWA time-weighted average XRF X-ray fluorescence yd 3 

### cubic yard(s)EA Project No. 14342.26 Page 1 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 1. INTRODUCTION

This document presents the Remedial Investigat ion (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 Houst on, 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 Feasibil ity 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 fram ework and requirements for this effort.

The OU 3 RI field program was conducted in acco rdance 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 pr oject-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) Re port 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, wh ich includes residential crawlspaces and those

residential areas that were not addressed duri ng 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 involve s the investigation and study of OU 3 (i.e., residential crawlspaces and the residential area s 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:EA Project No. 14342.26 Page 2 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### • Area Reconnaissance/Interviews—Reconnaissan ce activities and quali tative surveys were performed for the following purposes:

⎯ Confirm the status of resi dential properties addresse d during the OU 2 RI/FS and

removal actions.

⎯ Determine the location/status of resi dential 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 dur ing 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 ch ip samples from corresponding structure locations for lead speciation analyses.

• Risk Assessment—HHRA was conducted to ch aracterize and quantif y the current and potential human health effects that would preva il, 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. Th e most recent updated dietary lead intake estimates for each age category was used in the IEUBK Model. EA performed deterministic and probabilistic risk analys es based on the lead-soil exposure point

concentration. The EPA OU2 removal action le vel was used in a weight of evidence approach in conjunction with the output from the IEUBK Mo del to determine residences that may be subject to a remedial decision (based on EPA’s discre tion). 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 co llected 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.EA Project No. 14342.26 Page 3 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 2. BACKGROUND

This section contains a summary of the site history, key investig ations, 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 H ouston and 1 block south of U.S. Interstate Highway 10 (I-10) in an area of mi xed industrial and residential land use. This part of Houston is known as the “Fifth Ward.” The MDI pr operty 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 Bri nghurst Street to the west. Residential areas are adjacent to the east, west, a nd north sides of the site . Industrial areas are adjacent to the south side of the site. The MDI site includes the resident ial yards or properties and high-access areas surrounding the former foundr y. High-access areas include schools, child daycare centers, playgrounds, and churches th at surround the fenced boundaries of the site.

In 1926, TESCO began operations as a metal casti ng foundry at the MDI site. A second foundry was built on the eastern portion of the site dur ing the latter half of 1970. TESCO primarily manufactured specialty molded parts such as large wheels, tracks, and mining equipment. Various grades of steel, incl uding high carbon, chrome molybdenum , high nickel, and stainless

steel were cast at the TESCO f acility. During the mid-1980s, the s outhern portion of the site was leased to Can-Am Resource Group, which conducte d a spent catalyst recy cling operation. In 1990, MDI bought the TESCO note from Texas Comm erce 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 ov er a year before declaring bankruptcy (TTEMI 2005b).

The onsite facilities were demolished as a salv age 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 a nd administration building, a railro ad boxcar used as a former storage building, a large me lt transformer in the northwest corner of the site, and several concrete structures formerly used as vats.

EPA believes that the air emissions from the fo rmer foundry, which contained particles of lead, may have caused the on and offsite soils to beco me 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 cont amination that may have impacted the on- and offsite soils may include lead-based paint and hi storical deposition from vehicular lead-based fuel emissions, among other possible sources.

The MDI offsite area was originally a concern du e to the stacks and blowers that operated on site, as well as fugitive emissions. Informa tion in the Texas Commission on EnvironmentalEA Project No. 14342.26 Page 4 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### Quality’s (TCEQ; formerly the Texas Natural Resource Conservation Commission [TNRCC]) permit files indicates that there were three fu rnaces 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 locat ed adjacent to and west of the site; it has

since been reconstructed at a new location west of the site and outsi de of the Modeled Air Deposition Area and East Blower Area (also know n as the Study Area). Residential areas are located adjacent to the site; there are an estimated 942 hous ing 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 si te. 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 concu rrent but located in diffe rent 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, ch ild daycare centers, playgrounds, and churches.

• OU 3 (Residential Crawlspaces and those Residential Areas Not Addressed under OU 2)

― Residential crawlspaces, residential yard s or properties, and high-access areas located within the Modeled Air Deposition Ar ea and East Blower Area (Study Area) that were not addressed during pr evious RI/FS activities and removal actions conducted for

MDI.

This Task Order addresses the RI/FS for OU 3, wh ich includes residential crawlspaces and those residential and high-access areas not addressed under OU 2 that ar e located within the Modeled Air Deposition Area and East Blow er Area (Study Area). The M odeled Air Deposition Area is defined as the modeled air deposition area bound by the 400-milligrams per kilogram (mg/kg)EA Project No. 14342.26 Page 5 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 ha ve been deposited onto the ground surface, and (2) soil-lead concentrations may potentially m eet or exceed the EPA Region 6 Human Health Medium-specific Screening Levels (MSSLs) for h eavy metals associated with foundry activities (TTEMI 2005a). The preliminary air quality imp act 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 histor ic foundry operations. These assumptions were necessitated by the limited historical informati on regarding site operations. The planning-level modeling that was performed resu lted in the delineation of cont ours (isopleths) with different estimates of deposition rate s corresponding to different to tal lead concentrations:

• At the 1.8 grams per square meter per year (g/m 2 

### -year) isopleth, the lead concentration is expected to be about 1,6 00 mg/kg (immediate vicinity of the site [OU 1]).

• Between the 0.8 and 1.8 g/m 2 

### -year isopleths, the lead concen tration is expected to be greater than 400 mg/kg, but less than 1,600 mg/kg (concen tration decreases with increasing distance from the site).

• Beyond the 0.8 g/m 2 

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

During the 2003 OU 2 RI, all reside nces within the pr edicted 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/m 2 

### -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 Pre ss Street (offsite East Blower Ar ea) 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 with in the Modeled Air Deposition Area and East Blower Area (Study Area) that we re 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 th at eliminates, reduces, or controls risks to human health (EA 2007c). This RI Report speci fically 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 sa mples contained lead exceeding the action level of 500 mg/kg. Between February and July 1996, EPA collected 100 soil samples from ya rds and vacant lots;EA Project No. 14342.26 Page 6 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 gr eater 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 Enviro nmental Policy (City of Houston) received a Superfund Redevelopment Initiative (SRI) Grant. The City of H ouston was selected to receive one of 10 pilot grants being awarded nationw ide under the EPA’s innovative SRI. The City received $100,000 to conduct a reus e assessment and public outreach to help determine how best to redevelop the former MDI property in the Fi fth Ward. The MDI Citi zen Advisory Group, in the “Reuse Assessment Report,” recommended reuse of the site for mixed residential, organized recreational, and neighbor hood-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 addresse d 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 craw lspaces 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/st abilization, if necessary) of approximately 13,600 cubic yards (yd 3 

### ) of soils with lead concentrati ons equal to or greater than 500 mg/kg to a maximum depth of 11⁄2 feet be low ground surface (bgs), and approximately 3,000 yd 3 

### of soils stockpiled within OU 1 from a previous removal ac tion; transportation and disposal of the treated and untreated soils at a permitted offsite waste disposal facility.

• Transportation and disposal of approximately 31,621 yd 3 

### of debris (nonhazardous debris, foundry sand, and slag), asbestos-containing ma terial, and an underground storage tank at a permitted offsite waste disposal facility.

• Excavation and disposal of approximately 2,100 yd 3 

### of soils contaminated with polycyclic aromatic hydrocarbons, light non-aq ueous phase liquids, and total petroleum hydrocarbons at a permitted offsite waste disposal facility.

• Implementation of monitored natural atte nuation for impacted ground water, which includes source removal and long-term monitori ng for the ground water to ensure that constituents above clean-up goa ls are naturally attenuating.EA Project No. 14342.26 Page 7 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### • Implementation of institutiona l controls for both the soils and ground water to prevent exposure to soil contamination above acceptabl e 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 th e MDI property, represented by Waldron & Schneider, LLP, auctioned the 36 acres of prope rty (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 decisi on for OU 2 was “no further remedial action,” since previous removal actions had eliminated th e existing and potential risks to human health and the environment, so that no further acti on was necessary. The purpose of the removal

actions was to remove surface soil with concentr ations of lead that e qualed 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 coul d 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 Investme nts, 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 requirement s of the Agreed Order. Section 2.3.4 provides additional detail regarding th e 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 concentrat ions 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 contract or 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 reside ntial soil samples for l ead (see Section 3.0). Although the clean-up goal was se t 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 preci sion of the Niton® portable XRF analyzer. The average relative standard deviation was determin ed by averaging the reported instrument error values associated with field XRF lead analysis for all residential soil samples analyzed. Therefore, any property with re ported 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.EA Project No. 14342.26 Page 8 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### The action level for lead in soils (463 mg/kg) wa s determined to be protective of human health based on IEUBK modeling of actual data collect ed from other EPA Region 6 Superfund sites, namely RSR Corporation Superfund Site (EPA 1995), Tar Creek Superfund Site (EPA 1997),

and Delatte Metals S uperfund Site (EPA 2000b).

2.3.2 2005 Removal Action

During May and June 2005, a second EPA remo val 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 previous ly addressed during the 2003 EPA removal action ( Figure 2 ). Two of the five propert ies had been addressed during the 2003 removal action, but required additional remediation based on subsequent data evaluation. A total of 308 yd 3 

### 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-contam inated 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 determin ed during the 2003 RI/FS. During the removal operations, approximately 1,760 yd 3 

### 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 re moval actions associated with the MDI site (1996 – 2006).

2.3.4 OU 1 Remedial Action

Under the Agreed Order for OU 1 (EPA 2006), CG I 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 Fe bruary 2007. The RA for OU 1 is complete pending final approval from EPA.EA Project No. 14342.26 Page 9 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 3. REMEDIAL INVESTIGATION ACTIVITIES

The OU 3 RI activities were performed betwee n 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 proper ties; 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 Distri ct (HCAD) office. Letters describing the project a nd 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 n ecessary. 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 coordina tion with property access activities, a qualitative field survey was conducted to (1) determine wh ich homes, addressed under the RI/FS for OU 3, have accessible crawlspaces of 6 in ches or greater; and (2) confirm the locations of residential properties which were not addres sed during the OU 2 RI and confir m information gathered from

the HCAD office.

3.1.1 Residential Crawlspaces

During the field reconnaissance, EA identified 225 OU 3 residentia l 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 gr ound clearance greater than or equal to 6 inches) and 26 were deemed inacce ssible (vertical ground clearance of less than 6 inches) ( Table 2 ). EA visually estimated the vertical height of each cr awlspace, potential sampling locations, and whether the crawlspa ce 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 sm all 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 acce ssible crawlspaces ( Table 2 ).

EA also identified residential structures w ith accessible crawlspaces within the Background Study Area ( Figure 2 ), a neighborhood believed to be uni mpacted by MDI site operations.EA Project No. 14342.26 Page 10 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### Based on air quality impact modeling of hist oric 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 residen tial 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 incl uded 53 residences (i.e., habitable structures present on the property) a nd 41 vacant lots. Due to property access issues, EA could only gain access to sample 14 residenc es (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 pr operty access; (2) owners and/or tenants that were nonresponsive to repeated attempts to obtain cons ent; (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 propertie s (with unoccupied or i nhabitable 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 obta in property access, durin g 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 si nce it is likely that responses will vary from season to season; therefore, all questions with a tem poral 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 co llected 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. Base d 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 childre n played in the crawls pace 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 pe ts) that spent time in the crawlspace.EA Project No. 14342.26 Page 11 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### • 3 pets at 3 separate residences (1 pet per re sidence with pets reported to spend time in the crawlspace) reportedly sleep with the child ren an average of 1.8 days per week.

• 11 of 41 residences reportedly grow the fo llowing 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-doo r surveys was used in the determination of exposure parameters for the HHRA, qualitative ev aluation of risk estimates in the uncertainty evaluation of the HHRA, and reconciliation of an y investigative data gaps in preparation for sampling activities.

3.3 SAMPLE COLLECTION SUMMARY

During the RI for OU 1 and OU 2, air quality im pact modeling was conducted to predict where (1) particulate matter from hist orical stack emissions would ha ve 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 w ith foundry activities (TTEMI 2005b). The model was based on a number of conservative input pa rameters regarding emission controls and lead concentrations in feedstock during historic foundry operations. These assumptions were necessitated by the limited historical informati on regarding site operations. The planning-level modeling that was performed resu lted in the delineation of cont ours (isopleths) with different estimates of deposition rates corresponding to differe nt total lead concentrations (TTEMI 2005b):

• At the 1.8 gram per g/m 2 

### -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/m 2 

### -year isopleths, the lead concen tration is expected to be greater than 400 mg/kg, but less than 1,600 mg/kg (concen tration decreases with increasing distance from the site).

Beyond the 0.8 g/m 2 

### -year isopleth, the lead concentration is expected to be less than 400 mg/kg ( Figure 2 ).

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

Determine whether the average lead concentrat ions 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).EA Project No. 14342.26 Page 12 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### The study boundary for each residential ya rd includes exposed 2,500-square-foot (ft 2 

### ) surface areas (e.g., sod and/or soil) within each yard; so me 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 collectin g 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 de pth 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 w ithin the perimeter of the residential structure. Figure 4 illustrates the typical conf igurations for collecting craw lspace surface soil samples. The vertical study boundary include s 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 correlat ion 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 resi dential 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 struct ures identified during reconnaissance activities ( Table 2 ), in accordance with the EPA RI/FS SOW (EPA 2007b) and SAP (E A 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 struct ure), 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 subseque nt 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 aEA Project No. 14342.26 Page 13 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### digital camera; Appendix G provides an electron ic 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 discusse d 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 structur es to establish background crawlspace lead

concentrations to differentiate between na turally-occuring or anthropogenic background (e.g., automobile emissions) lead concentr ations 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 wher e 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 cr awlspace 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 perfor med to evaluate whether a

correlation existed between lead de tected in crawlspace soil and a ny lead-based paint detected on the exterior walls of the corresponding structure. A strong correlation woul d 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-ft 2 

### surface area (e.g., front and back yards) for 14 residences (i.e., habitable stru ctures 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-ft 2 

### 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 mentione d soil intervals, a 0 to 1-inch bgs soil sample was collected. The following pro cedure 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 usi ng 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 tran sferred into a labeled resealable plastic bag for subsequent processing at the support zone.EA Project No. 14342.26 Page 14 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

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

Following sample collection, the aceta te sleeves were stored for s ubsequent sample processing at the support zone. The shallow soil borings were backfilled with clean sand. During sampling activities, the sampling team documented site co nditions, including the samp le locations, with a digital camera. Post-sampling site conditions were also docu mented; 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 wh ere OU 3 residential yard soil samples were collected.

During the previous 2003 OU 2 RI , 40 residential yard soil samp les were collected from the Background Study Area using the same sa mpling methodology discussed above ( Figure 6 ). EA

did not collect additional reside ntial 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 crawls pace 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, a ny observed paint chips were retained. The soil was then homogenized in an aluminum pan using a disposable plastic sc oop and transferred into a labeled resealable plastic ba g for subsequent sample proces sing. During sampling activities, the sample team documented the condition of soil (p aint 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 performe d during the RI field program to protect field personne l. Personal air sampling for to tal airborne pa rticulate matter (PM) and lead was conducted using pre-weighed filter cassettes and a Gi lian GilAir-5TM Sampler (per National Institute for Occupational Safe ty 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 ai rborne PM and lead sample concentrations were collected during an 8-hour work schedule usi ng hand-held air sampling equipment on or near personnel. Ambient air was analyzed in acco rdance with NIOSH Method 0500 (Particulates Not Otherwise Regulated, Total) and NIOSH Me thod 7300 (Elements by Inductively-coupled Plasma) to determine total dust and lead emissions, respectively. Pre-weighed filter cassettes were submitted to TestAmerica Laboratories in gr oups of up to 20 samples for batch analysis on a 3-day turnaround time basis.EA Project No. 14342.26 Page 15 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### PM and lead was also monitored continuously during the RI field progr am during residential yard/crawlspace soil sampling and soil sample processing/XRF analysis.

3.3.6 Personnel Blood-Lead Testing

All field personnel performing residential ya rd/crawlspace soil sampling and soil sample processing/XRF analysis were required to under go 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 du ring sampling activities. All logbook entries and field forms were dated and signed by the indi vidual making the entries. The logbook entries included the following: names of team personne l, dates and times of all entries, weather conditions, descriptions of all site activities, site obser vations, residential pr operty 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 co mpleted for each of the properties investigated during OU 3 sampling activities. Appendix C presen ts a copy of the property sketches prepared during sampling activities.

3.5 SAMPLE DESIGNATION

Each sampling location was designated with a un ique alphanumeric desi gnation 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 thre e fields that are separated by dashes; for example:

BG-1004-U

.

– The first field, “ BG ,” identifies the sample as re presenting background crawlspace soil (Background Study Area).

– The second field, “ 1004 ,” represents the sample identif ie r as illustrated on Figure 6

.EA Project No. 14342.26 Page 16 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### – 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 thre e 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 designa tions described above; for example,

CS-1021-S-D

, BG-1004-U-D , and RY-1015-6-12-U-D

.

• Equipment Rinsate Blan k Sample Designation. Equipment rinsate blank samples were identified sequentially beginning with ER-1

.

3.6 SAMPLE P ROCESSING

Sample processing, including sievin g, drying (if needed), grinding (if needed), and field-portable XRF analysis of the residential yard and craw lspace soil samples, occurred in the sample processing area (support zone). The following s ections discuss the procedures for processing and preparing samples for analysis at the samp le 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 samplesEA Project No. 14342.26 Page 17 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 re sealable 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 th e unsieved residential yard and crawlspace soil samples were reserved for subsequent analysis to develop a particle size correlation between sieved and unsieved samples collected fr om 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 “sieve d” samples were placed into clean resealable plastic bags with the sample id entification 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-la boratory 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-ft 2 

### 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 include d the following steps:

• Transfer the sample aliquots for a specific depth interval from each of the five acetate sleeves (representing one 2,500-ft 2 

### area or yard) into a labeled plastic resealable bag.

• Homogenize the sample for a specific dept h 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 a ny large debris such as sticks, rocks, etc.

• Placing the sample into a new resealable plasti c bag with the sample identification and an unsieved designation.

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

discussed in Section 3.6.3.EA Project No. 14342.26 Page 18 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 3.6.3 Residential Yard and Crawlspace Soil Sample Preparation for Analysis

Soil samples underwent the following additional pro cessing 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 necessar y, 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 c up with the appropriate TeflonTM collar.

• Labeling each sample with the appropriate sample designation, eith er directly on the sample cup or on a resealable bag containing the sample cup.

Each sample underwent analyses in the field la boratory (support zone) using a field-portable XRF analyzer. In order to establish a correla tion between the field XRF and fixed-laboratory data, approximately 10 percent of the soil sa mples were submitted to the EPA Region 6 Laboratory for lead analyses. The same material tested using the fiel d-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 fi xed laboratory for lead analysis was placed in laboratory-grade 4-ounce glass, wide-mouth jar with a Teflon TM 

### -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 z ones (drip lines) underwent minimal preparation prior to submittal for lead speciation testing. Ho mogenized soil was transferred from the plastic bag into laboratory-grade 4-ounce gl ass, wide-mouth jar with a Teflon TM 

### -lined cap.

3.7 SAMPLING HANDLING AND CUSTODY PROCEDURES

This section presents the sample identificati on, sample handling, and sample custody procedures followed during the RI activities. EA used EP A’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 impor ted into a Microsoft Access® database, which provided the framework around whic h analytical data were asse mbled. 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 trafficEA Project No. 14342.26 Page 19 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 trans ported to the EPA Region 6 Labo ratory in Houston, Texas for chemical analysis. Each cooler wa s 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 th e distribution of lead in soils was related to particle size. The EPA Region 6 Laboratory anal yzed 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 Laborator y analytical data packages.

The following soil samples (including field dupl icates) 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 (sam ple 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 re sults were rejected, yielding 100 percent of the data usable. Data without qualifiers and data qualif ied as estimated are usable for purposes in supporting project objec tives. The data were also found to be representative and comparable for the samples. Precis ion and accuracy were acceptable.

3.8.1 XRF versus Laboratory Evaluation

A statistical analysis was conducte d to test the hypothesis that XR F 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 lin ear model using least squares regression:EA Project No. 14342.26 Page 20 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### X



### RF LAB α 

### β = 

### + × 

### where,



### α = the intercept of the regression β 

### = the slope of the regression.

The coefficient of determination (r 2 

### ) 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 expe cted values under the null hypothesis

H 0 

### : 

### 0 α = , and 1 β =



### .

The results of the regression analysis are presen ted in Figure E-1 and Ta ble E-1 (Appendix E). The analysis shows an r 2 

### of 0.93 indicating a hi gh degree of precision between collocated XRF and laboratory data. Both of the regression coeffi cients where consistent with their values under

H 0 

### ( 

### 0 α 

### = and 1 β 

### = 

### ) indicating that XRF provides an accu rate 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) si eve to obtain the fine fraction (<250 μm) of the soil sample. This fraction of the soil matrix was colle cted to represent the particle size (<250 μm) that tend s 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 usi ng the XRF, as sieved and unsieved, to assess

whether the distribution of meta ls 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 th at sieved and unsieved samples would be in close agreement. This hypothesis was tested by f itting 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:

H 0 

### : 

### 0 α = , and 1 β =



### .

The r 2 

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

between sieved and unsieved XRF data.EA Project No. 14342.26 Page 21 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### The data scatter plot and LTS regression trendline for yard da ta is presented in Figure E-2 (Appendix E). For yard samples, the unsieved fraction was in good agreement (r 2 

### = 91%, α ≈ 0, β ≈ 1) with the sieved fraction (Figure E-2 and Table E-2, Appendix E); and, therefore, H 0 

### was not rejected. The data set, however, contained one extreme value (sampl e ) in which the unsieved fraction was approximately 30% higher than the sieved fraction. This extreme value may indicate that there are signif icant differences in the sieved and unsieved fractions in highly contaminated yard soil.

The data scatter plot and LTS re gression trendline for crawlspace data is presented in Figure E-3 (Appendix E). For yard samples, the unsieved fraction was in good agreement (r 2 

### = 96%, α ≈ 0, β ≈ 1) with the sieved fraction (Figure E-3 and Table E-3, Appendix E); and, therefore H 0 

### was not rejected. As with the yard data, the crawls pace data set contained on e extreme value (sample ) in which the unsieved fraction was appr oximately 60% higher than the sieved fraction. This extreme value may indicate that there are significant differences in the sieved and unsieved fractions in highly contaminat ed crawlspace soil.

3.8.3 Sieved Crawlspace versus Sieved Yard Soil Fractions

A statistical analysis was conducte d to compare sieved crawlspace so il to sieved yard soil using ordinary least squares regre ssion 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:

H 0 

### : 

### 0 α = , and 1 β =



### .

The r 2 

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

XRF data.

The results of the regression analysis are presen ted in Figure E-4 and Ta ble 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 grea ter levels of lead contamination, however, the crawlspace soil tends to be significantly mo re 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 (r 2 

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

and soil data sets should be treated as dis tinct data populations fo r the purposes of risk

assessment.EA Project No. 14342.26 Page 22 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### Because of the limited data set (only 3 residences with collocated unsieved data) for unsieved crawlspace soil and corres ponding unsieved yard soil, a statisti cal analysis was not performed for

the unsieved soil data set.

3.8.4 Field Duplicates

Seven pairs of field duplicates we re 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 analy tical results for lead showed inconsistencies between duplicate and original sample results. In consistencies noted with metals re sults may indicate heterogeneity

of matrix and uneven distri bution of contaminants in the sample matrix.

3.8.5 Equipment Rinsate Blanks

Fourteen equipment rinsate blanks were collect ed and analyzed for metals to measure the effectiveness of sampling equipment decontamina tion procedures. Lead was not detected above the reporting limit for the equipment rins ate blanks, unless otherwise noted.

Lead was detected in equipment blanks co llected on 27, 28, and 29 February, 1 March, and 30 and 31 July 2008. Lead was also reported for th e preparation method bla nk associated with the equipment blanks collected in July 2008. Equi pment rinsate contamination is indicative of improper or inadequate equipment decontaminat ion. However, the rela tive 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) wa s followed with respect to proposed sampling locations and procedures. Most of the deviatio ns 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 prog ram, some duplexes were counted as 2 residences if they met the following requiremen t: in the case where each half of a duplex was similar in size to a single-family residen ce, each half was trea ted 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 v acant lots that were not addressed during the

OU 2 RI:

– Twenty of the properties were samp led during the 2008 OU 3 RI, including 14 residences (i.e., habitable structures pr esent 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 Ar ea) could not be located or were not listed in HCAD; therefore, thes e properties were not sampled.EA Project No. 14342.26 Page 23 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### – Nine owners of residences and/or vacant lots were not responsive to requests for access to sample the property; therefor e, 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 si gning 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.EA Project No. 14342.26 Page 24 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 Deposi tion 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 M odeled 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 delin eated 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 residen tial properties) and 119 residential crawlspace soil samples (representin g 78 residential properties), were collected and analyzed for lead. In addition to the soil sa mples 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 analys es performed as part of this investigation. Appendix E presents the fixed laboratory analytic al data packages. Appendix G contains an electronic copy of the project an alytical database on a CD (Microsoft Access® format).

4.1 SOIL CONTAMINATION

During the OU 3 RI, surface soil samples collec ted 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 (E A 2008b), lead showed a strong correlation (r 2 

### = 0.93 > 0.80) between XRF and fixe d laboratory data. Lead result s for residential yard soil were compared with three surface soil screening criteria in a hi erarchical approach: (1) EPA Regional Screening Levels (RSL) for the resi dential land use scenar io (EPA 2008), which replaced the EPA Region 6 MSSLs (EPA 2007c) as screening criteria ; (2) the MDI median background lead concentrations; a nd (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 Backgr ound 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 th e distribution of lead in surf ace soils in the OU 3 residential crawlspaces and yards.EA Project No. 14342.26 Page 25 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 cr awlspaces 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 ac tion level was evaluated in the HHRA Report (EA 2009). Section 5 presents a summary of the HHR A 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 con centration 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 reside ntial yard soil samples ranged from 14.2 to 1,190 mg/kg. Soil samples collected from 6 of the 20 residential prope rties contained lead concentrations equal to or greater than the EPA residential RSL of 400 mg/kg ( Table 5 ). Appendix D presents a tabulated summa ry of all the analytical data.

Lead was only detected at concentrations equal to or greater than the EP A 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 inte rval (901.5 mg/kg) than in the 0 to 6-inch bgs soil depth interval (764.6 mg/kg). Lead concentrations for soil sample s 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-in ch 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 or der to assess the potential sour ce of lead contamination. Following completion of the 2003 RI field program, the EPA National Exposure Research Laboratory in Las Vegas, Nevada (NERL-LV) eval uated the data to make a source determination (TTEMI 2003; 2005b). In additi on, during the 2008 RI field program, EA performed (1) in situEA Project No. 14342.26 Page 26 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### XRF testing of the exterior pain ted 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 sample s. The following sections also present background information about th e MDI site and vicinity.

4.2.1 Site Geology

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

consists of former barrier island and beach de posits. 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. Ther e 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 Bric k Works brickyard. In 1926, the TESCO began operations as a metal casting foundry initiall y 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. distri ct 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 th e site. The primary anthropogenic source of soil contamination is lead potentially associated with former foundry operations. The

MDI site is also located in clos e 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 sta tistical 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 NE RL-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 a nd East Blower Area).EA Project No. 14342.26 Page 27 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### • OU 1 is probably the source of some relativ ely 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 Bac kground Study Area, and both are very different from the onsite concentrations (OU 1).

• OU 1 has a distinctive “fingerprint” characte rized by relatively high levels of chromium, iron, manganese, molybdenum, nickel, and zirc onium; 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 characteri zed by a strong correlation with zinc. One possible source is paint with a combin ation of lead carbonate and zinc oxide pigments.

Onsite (OU 1) samples contained a few elevated lead values, but th ey were not characteristic of the site in general, which is low in lead. Th e 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 c ontain 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 Ar ea, and Background Study Area.

Additionally, a statistical eval uation of the OU 2 crawlspace so il data concluded that no significant correlation exists between the lead co ncentrations in crawlspace soil and the lead concentrations in the yard soil. That is, the l ead concentration in the yard samples is not a good predictor of the lead co ncentration 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 NE RL-LV directed the assessment of bag house and on- (OU 1) and offsite (Modeled Air Deposition Ar ea and East Blower Area) soil samples using scanning electron microscopy (SEM) analysis. A definitive correlation could not be established

between the lead contaminati on found at the MDI site and the offsite (Modeled Air Deposition Area and East Blower Area) lead contamina tion 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 sulf ate) 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 addi tion, 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) a nd the Background Study

Area.EA Project No. 14342.26 Page 28 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 4.2.4.3 Ratio of Metals in Soils

During the 2003 RI, five samples of bag house wa ste 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 at tributable to onsite activi ties, the ratios of the

metals should be similar.

Lead, chromium, and molybdenum were selected as heavy metals that are lik ely 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 rati os 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 Depos ition 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 so ils. 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. Tw o likely sources are tail pipe emissions from automobiles during the period when leaded gasoline was in use (pre mid-1 970s), 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 exte rior painted surfaces

of OU 3 residential structures where craw lspace 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 perfor med to evaluate whether a

correlation existed between lead de tected in crawlspace soil and a ny 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/cm 2 

### ). The Department of Housing and Urban Developm ent (HUD)/EPA standard for lead-based paint is 1 mg/cm 2 

### , as defined in Title X of the 1992 Housing and Community Development Act. Lead in the exterior paint exceeded the HUD/EPA sta ndard for lead-based paint in 12 of the 76 OU 3 residential structures where crawlspace soil samp les were collected. Of the 12 lead-based paint exceedances, only five corresponding crawlspace so il 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 crawlspa ce soil-lead concentrations.EA Project No. 14342.26 Page 29 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### Linear regression analysis of the data set indicates that a poor co rrelation exists between average

lead concentrations measured in residentia l exterior paint and corresponding soil-lead concentrations for OU 3 crawlspaces and the Bac kground Study Area (i.e., the lead concentration

detected in the exterior walls of a resident ial structure not a good pr edictor 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 r 2 

### values of 0.2057 (sieved) and 0.0000004 (unsieved) indicate that a very poor correlation exists between the l ead concentrations detected in the exterior paint and crawlspace soil for a particular residentia l 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 resi dential 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 struct ure located within OU 3.

Therefore, lead-based paint is apparently no t contributing a significan t portion of the lead detected in crawlspace soil samples. Subse quent lead speciation te sting 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-b ased paint is a significant contributing factor to the crawlspace soil lead content. Representative samples submitted to the laboratory, FAI Materials Testing Laboratory (FAI), Marietta Ge orgia, 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 resu lts of the lead speciation testi ng performed by FAI are presented in Appendix F.

The methodologies used by FAI for sample prepar ation, data collection, a nd testing are described below. Prior to examination, weighed portions of the samples were sorted under an optical microscope to identify and remove paint fragment s 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 per cent 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 accura cy of the method (see Table 2 of FAI report in Appendix F). The el emental 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 pa int chip samples are much higher th an the associated soil fraction.EA Project No. 14342.26 Page 30 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### The largest paint chips found in the paint chips samples were separately analyzed by SEMEDXS; these results showed much lower concentr ations of lead (see Fi gures 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 an alyzed by a Niton portable XRF unit. The first round of testing was inconclusive due to bac kground issues (see Table 6 of FAI report in Appendix F). The samples were retested on a di fferent 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 major ity 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 fi ndings of the tests performed by FAI:

• There were leaded as well as unleaded pain t 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 pain t chips to soil shows there are more paint chips by weight in the drip line samples than the crawlspace sample s (see Table 1 of FAI report in Appendix F).

The conclusions of the report show that there ar e 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 resu lts are reflective of the samples submitted for evaluation and there is uncertainty extrapolat ing 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 pr ogram. 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 samp les collected from EA field personnel during residential yard/crawlspace soil sampling and soil sample processing/XRF analysis was analyzedEA Project No. 14342.26 Page 31 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 Permissi ble Exposure Limit, and personal air sampling

activities were discontinued.

4.3.2 Blood Lead

As discussed in Section 3.3.6, all field personne l performing residentia l yard/crawlspace soil sampling and soil sample processing/XRF analys is were required to undergo baseline and follow-up blood-lead testing to evaluate worker protection in co mpliance 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 ac tion level of 40 micrograms per deciliter ( μ g/dL).EA Project No. 14342.26 Page 32 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 5. HUMAN HEALTH RISK ASSESSMENT

EA prepared an HHRA Report (EA 2009) that ch aracterizes and quantifies the current and potential human health effects associated with ex posure 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 pr otective of children and adults.

EA performed a deterministic e xposure assessment to identify the magnitude of actual or potential human exposures, the frequency and du ration of these exposures, and the routes by which receptors are exposed. Figure 8 illustrates the primary sour ces, release mechanisms, and exposure pathways that were evaluated during the risk assess ment. The exposure assessment

included an evaluation of the lik elihood of such exposures occu rring and provided the basis for the development of acceptable exposure levels. In developing the exposure assessment, EA developed reasonable maximum estimates of exposu re 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 expo sure assessment to further char acterize uncertainty associated with exposure time and exposure point concentr ation 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 crawlsp ace mindful of the season.

EA identified critical assumptions (e.g., b ackground concentrations and conditions) and

uncertainties in the HHRA. A “Monte Carlo” eval uation was used to addr ess uncertainty in the exposure assumptions.

A deterministic risk analysis is one in which a discrete value is repr esented 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 norma l, normal, or triangular) for a large number of times (such as 10,000 random picks) , and calculating an objectiv e from these picks. The objectives in this case are determining the e xposure point concentration (EPC) and crawlspace clean-up level statistical distri butions. The individual distribu tions, 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 cal culation of the object ive 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 craw lspace is generated. The large number of iterative selections from the yard a nd crawlspace distributions thus generates a data set for the objective from which a corresponding di stribution can then be identified. For risk management purposes, the objective data set and distribution (concentrat ion representative of yard and crawlspace exposure) can then be used to determine risk management objectives regarding potential clean-up. Th is differs from the standard deterministic method, which is based upon the discrete analysis of one con centration representati ve of the site.EA Project No. 14342.26 Page 33 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### The HHRA evaluated the prospe ctive “baseline” conditions af ter 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 a ddressed 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 evalua te 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- a nd post-2009 scheduled removal action)

• Deterministic residential yard soil for the single residence ( ) where the survey indicated children were pl aying in the crawlspace

• Deterministic sensitivity evaluation to evalua te preliminary remediation goals (PRGs) for crawlspaces.

The risk characterization results of these evalua tions are contained in the following sections. Appendix B of the HHRA Report (EA 2009) pres ents the probability graphs for those samples/locations evaluated using the IE UBK 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 e xposed children estimated to have a blood-lead level greater than 10 μg/dL ar e summarized in the tables referenced in the following sections. Numerical results of the m odeling 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 wa s 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).EA Project No. 14342.26 Page 34 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 5.1.1 Deterministic Residential Yard So il with No Crawlspace Exposure

To evaluate exposure to lead in residential yard soil in the abse nce of crawlspace exposure, the residential yard EPC was modeled using the IE UBK Model. IEUBK mode ling results indicate

that there are seven residential yards where the percentage of e xposed children with an estimated blood-lead level exceeding the lead level of concern of 10 μ g/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 acti on level of 463 mg/kg and the estimated percentage of children predicted to have a bl ood-lead level greater th an 10 μg/dL was greater than 10 percent. When modeled concentratio ns exceed the EPA removal action level of 463 mg/kg and the EPA OSWER-recommended thres hold 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 estimat ed percentage of children predic ted to have a blood-lead level greater than 10 μg/dL exceeded 5 percent, th e 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 concen tration was considered protective since the clean fill utilized in remediation of yard s had considerably lower lead concentrations of approximately 5 mg/kg. The results of this ev aluation 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 asso ciated with exposure to lead in soil.

The final OU 3 exceedance of the EPA OSWER-reco mmended 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 leve l of 463 mg/kg. The estimated geometric mean blood-lead concentra tion 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 likel y 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 remova l 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., sa mple 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/k g. A geometric meanEA Project No. 14342.26 Page 35 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 cons idered protective of human health due to the uncertainties associated with the conservative exposure a ssumptions 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 craw lspace 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 samp le were modeled using the IEUBK Model in a TWA approach. The results of the residential ya rd and crawlspace lead evaluation are presented

on Table 8A . Residential areas where the estimated pe rcentage 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 th e 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 remedi ation of yards had lead concentrations of approximately 5 mg/kg.

Three residences without cr awlspace samples (i.e., ) exceeded the EPA OSWER-recommended threshold of 5 percen t are not discussed further in this section because they were evaluated in the previous section.

Four additional residences with crawlsp aces ( ) 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 μ g/dL) was greater than

the EPA OSWER-recommended threshold of 5 percent and the yard composite sample

concentration exceeded the EPA rem oval action level of 463 mg/kg (see Table 8A ). The estimated percentage of children predicted to ha ve 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 resi dential yard is subject to a risk management decision (see Figure 9 ). Given that residen tial 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 pe rcent and the yard concentrati ons were greater than the EPA removal action level of 463 mg/kg, the yard c oncentration was replaced with the background lead concentration for the Study Area (150 mg/kg) to evaluate a post remediation scenario (seeEA Project No. 14342.26 Page 36 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### Table 8B ). Using the background lead concentration was considered protec tive since the clean fill utilized in remediation of yards had lead concentrations of approximately 5 mg/kg. The

results of this evaluation demons trate that remediation of yards with lead concentrations that exceed the EPA removal action level of 463 mg/k g 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-r ecommended threshold of 5 percent, but

was not discussed further in this section becau se 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 da ys a week exposure to crawlspace soil) that is not likely to occur base d 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 OS WER-recommended threshold of 5 percent but had yard concentrations less th an 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 we re less than the EPA re moval 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 concen tration 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 not ed that the crawlspace exposure, which is the contributing factor, was based on a conservative estimate of e xposure (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 concentr ations exceeding the EPA OSWER-recommended threshold of 5 percent, these residential yards ar e subject to a risk management decision (see Figure 9 ).

Risk Management Decision: At EPA’s discretion, these resi dential 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 Evalua tion with and without Hypothetical Crawlspace Exposure Using a Time-Weighted Average Approach

The TWA approach for evaluating exposure to resi dential yard soil and h ypothetical exposure to crawlspace soil in a “neighborhood risk” approach util izes the results from the prior evaluation. Neighborhood risk estimates apply to children who are exposed to residential yard andEA Project No. 14342.26 Page 37 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### crawlspace soil in the neighborhood. It is assumed that the child spends equal time in all residential yards in the neighbor hood. It is also based on a co nservative 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 ri sk estimates are useful in evaluating the potential risk to children in the community bot h before and after remediation has occurred. To this end, the neighborhood risk es timates provided below for the residential yard and crawlspace lead neighborhood risk ev aluation 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 thre shold of 5 percent. Also, the average percentage of exposed children with a predicte d blood-lead level greater than 10 μg/dL for only

those residences w ith crawlspaces (see Table 8A ) is 10 percent, which is greater than the EPA

OSWER-recommended thres hold of 5 percent.

When the neighborhood risk evaluation demons trates that the EP A OSWER-recommended threshold of 5 percent is exceeded, then resi dential 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 pe rcent and the yard concentrati ons were greater than the EPA removal action level of 463 mg/kg, the yard c oncentration 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 protec tive 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 leve l greater than 10 μg/dL

for OU 3 residences with and without crawls paces in a post-remedi ation scenario (see Table 8B ) is 1.6 percent, which is less th an the EPA OSWER-recommended th reshold 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 crawls paces in a post-remedi ation 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 predictio ns greater than the EPA OSWER-recommended threshold of 5 percent, the results of this evalua tion demonstrate that remediation of yards with

lead concentrations that exceed the EPA remova l action level of 463 mg/k g 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 so il 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 surv ey indicated that a single residence (i.e., ) indicated that children played in the craw lspace for 0.5 hour per day; this crawlspace was sampled during the OU 3 field investigation and the lead con centration was 443 mg/kg. The front and backEA Project No. 14342.26 Page 38 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### yards were sampled during the OU 2 field invest igation 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 rem oval action level of 463 mg/kg, an evaluation of potential exposure in the absence of remedial ac tion 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 exceedin g the lead level of concern (10 μ g/dL) was 26 percent for the 2 days per week crawlspace exposure frequency us ing a TWA EPC of 754 mg/kg; the results of the 1 day and 3 days per week exposure fr equency scenarios were 25 and 26 percent, respectively. These results exceed the EPA OSWER-recommended threshold of 5 percent.

When modeled concentrations exceed the EPA re moval action level of 463 mg/kg and the EPA

OSWER-recommended threshold of 5 percent is exceeded, then the re sidential 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 deleteriou s 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 E valuate 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 ac tion level goal or PRG has not b een 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 PbS Crawlspace 

### 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 fre quency and duration in th e crawlspace area on the risk and cleanup level(s). A pr obabilistic evaluation was performe d to study the whole range of changes in the exposure frequenc y and duration and quantitatively evaluate the uncertainty in these exposure parameters and their e ffect on the risk and cleanup level.

TWA results indicate that composite crawlspa ce 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 crawls pace 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 fre quency is 2 days per week for 2 hours per day, the average OU 2 and OU 3 residential ya rd concentration is 289 mg/kg, and the EPAEA Project No. 14342.26 Page 39 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### removal action level of 463 mg/kg is used as the TWA concentration, th en 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 w eek 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 probabilis tic risk evaluation.

Risk Management Decision: It was demonstrated that cons idering properties with an EPC (TWA or otherwise) greater than 463 mg/kg in risk management decisions is appropriate to mitigate the potential deleterious effects asso ciated with exposure to lead in soil.

5.2 PROBABILISTIC RISK ASSESSMENT

A probabilistic approach was employed to furt her quantify residential crawlspace exposure. Based on EPA methodology, lead is evaluated via th e 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 freque ncy of use and the like lihood 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. Se veral 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 wint er, spring, summer, fall, and annual average to capture potential seasonal variations on exposure. While total time spen t outside varied with season, time spent in the crawlspa ce was constant throughout the year.

The scenarios were first evaluated incorporati ng 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 da ta 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 su mmary 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 concentr ation in the yard. Th e concentration in the crawlspace had a much lower im pact on the result for EPC and crawlspace clean-up value. These results indicate that crawlspace concentrati on has relatively little c ontribution to risk from

lead at the site.

The results of the probabilistic risk assessment ar e 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 75 th 

### percentile can be used as a starting point for risk management purposes.

The 75 th 

### percentile for incorporati ng OU 2 and OU 3 yard and crawlspace lead data (Model Run 1, pre-removal action) for the cr awlspace clean-up goal was 1,612 mg/kg.EA Project No. 14342.26 Page 40 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 un certainties, the potential effect on the results of the risk assessment is not expe cted 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 ex ceeding the EPA RSL of 400 mg/kg and the EPA removal action level of 463 mg/kg were evalua ted 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 μ g/dL) was greater than the EPA OSWER-recommended threshol d of 5 percent. Therefore, to mitigate the potential deleterious effects associated with e xposure 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.EA Project No. 14342.26 Page 41 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### • Residential yards with and without crawlspace s 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 leve ls greater than 10 μg/dL is greater than 5 percent, may be considered for remedial action to mitigate the potential deleterious effects associated with expos ure to lead in soil.

Several uncertainty factors (e.g., th e 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 fre quency is 2 days per week for 2 hours per day, the average OU 2 and OU 3 residential ya rd 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 w eek 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 probabi listic risk evaluation.

Please note that the deterministic sensitivity evaluation was performed to demonstrate the impact of variability and uncertainty of exposure fre quency and duration in th e crawlspace area on the risk and cleanup level(s). A pr obabilistic evaluation was performe d to study the whole range of changes in the exposure frequenc y and duration and quantitatively evaluate the uncertainty in these exposure parameters and their e ffect on the risk and cleanup level.

5.4.2 Probabilistic Risk Evaluation Summary

A probabilistic evaluation of exposure parameters was perfor med on OU 2 and OU 3 residential yards and crawlspaces. The analysis was performe d 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 cl ean-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 75 th


### percentile of 348 mg/kg for EP C and of 2,289 mg/kg for clean-up goal based on an annual average of time spent outside in yards and craw lspaces (Model Run 2) after scheduled removal actions. The probabilistic an alysis also showed a 90 th 

### 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 concentr ation in the yard. Th e concentration in the crawlspace had a much lower im pact on the result for EPC and crawlspace clean-up value. These results indicate that crawlspace concentrati on has relatively little c ontribution to risk from

lead at the site.EA Project No. 14342.26 Page 42 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### As a potential clean-up level for OU 3 crawlspaces, the 75 th 

### percentile can be used as a starting point for risk management purposes. The 75 th 

### 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.EA Project No. 14342.26 Page 43 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 6. CONCLUSIONS

This section summarizes the CSM, RI considera tions, and risk assessmen t considerations that

can be used to determine additi onal 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 depositi on of lead from former foundry operations (OU 1). OU 3 includes offsite residen tial 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 contac t with soil, and inha lation of newly re-suspended airborne soil particles; however, the crawlspa ce exposure is limited to childr en between the ages of 6 to 84

months.

6.2 REMEDIAL INVESTIGATION CONSIDERATIONS

The distribution of lead in OU 3 residen tial soil has been well characterized. Figures 6 and 7 present the lead concentrations in soil samples collected from OU 3 craw lspaces 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 evaluate d 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 gr eater than the EPA residential RSL of 400 mg/kg only in the upper 6 inches of soil, with the highest mean concentrat ion of lead concentrated in the top 1 inch of

soil. Detected concentrations of lead in OU 3 residential yard soil sa mples ranged from 14.2 to 1,190 mg/kg. Six of the 20 OU 3 residential proper ties sampled had lead concentrations above the practical removal action leve l 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 characte rized, additional investig ation may be warranted

once access can be obtained to the re mainder of the residential properties that were not addressed during the 2003 and 2008 RIs.

Approximately 40 percent (78 out of 195 identi fied) of OU 3 resident ial 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 ac tion level was evaluated in the HHRA Report (EA 2009). The distribution of lead in OU 3 residentia l crawlspace soil has b een well characterized.

Linear regression analysis of the data set indicates that a poor co rrelation exists between average

lead concentrations measured in residentia l exterior paint and corresponding soil-lead concentrations for OU 3 crawlspaces and the Bac kground Study Area (i.e., the lead concentration

detected in the exterior walls of a resident ial structure not a good pr edictor of the leadEA Project No. 14342.26 Page 44 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### concentration in crawlspace soil). Therefore, le ad-based paint is apparently not contributing a significant portion of the lead detect ed in crawlspace soil samples.

Subsequent lead speciation testing of sample s collected from residential crawlspaces and corresponding residential drip lin es 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 signifi cant 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 fr om sources other than lead-based paint.

6.3 RISK ASSESSMENT CONSIDERATIONS

Lead results from residential yards and craw lspaces were evaluated in deterministic and probabilistic evaluations.

6.3.1 Deterministic Evaluation

For OU 2, residential yard lead results ex ceeding the EPA RSL of 400 mg/kg and the EPA removal action level of 463 mg/kg were evalua ted 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 μ g/dL) was greater than the EPA OSWER-recommended threshol d of 5 percent. Therefore, to mitigate the potential deleterious effects associated with e xposure 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 crawlspace s 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 leve ls greater than 10 μg/dL is greater than 5 percent, may be considered for remedial action to mitigate the potential deleterious effects associated with expos ure to lead in soil.

Several uncertainty factors (e.g., th e 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 fre quency is 2 days per week for 2 hours per day; the average OU 2 and OU 3 residential ya rd concentration is 289 mg/kg; and the EPAEA Project No. 14342.26 Page 45 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 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 th at the crawlspace exposure was based on a conservative estimate of exposure (e.g., 2 days a w eek 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 probabi listic risk evaluation.

Please note that the deterministic sensitivity evaluation was performed to demonstrate the impact of variability and uncertainty of exposure fre quency and duration in th e crawlspace area on the risk and cleanup level(s). A pr obabilistic evaluation was performe d to study the whole range of changes in the exposure frequenc y and duration and quantitatively evaluate the uncertainty in these exposure parameters and their e ffect on the risk and cleanup level.

6.3.2 Probabilistic Evaluation

A probabilistic evaluation of exposure parameters was perfor med on OU 2 and OU 3 residential yards and crawlspaces. The analysis was run fo r 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 cl ean-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 75 th


### percentile of 558 mg/kg for EP C 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 90 th 

### percentile of 854 mg/kg fo r 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 75 th 

### 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 90 th 

### 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 75 th 

### percentile can be used as a starting point for risk management purposes. The 75 th 

### percentile based on residential yard and crawlspace data (Model R un 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 concentr ation in the yard. Th e concentration in the crawlspace had a much lower im pact on the result for EPC and crawlspace clean-up value. These results indicate that crawlspace concentrati on has relatively little c ontribution to risk from

lead at the site.EA Project No. 14342.26 Page 46 of 46 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### 6.4 SUMMARY

Several factors (including the depth issues id entified during the HHRA and uncertainty in the sources of lead and exposure a ssumptions) 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 hi storical deposition from vehicular lead-based fuel emissions and residential lead-based paint.

The deterministic risk assessment evaluated resi dential 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. Natu rally, one would conclude that the residential crawlspaces must then have poten tial unacceptable deleterious eff ects, which would be true if children were actually exposed to crawlspace soil. However, the community surveys indicated

that there was little to no r eal exposure to crawlspace soils (see Section 3.2). Nevertheless, remediation of residential yard and crawlspace soils, if necessar y, 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 fo r combined residential yard and crawlspace exposure. The probabilistic risk assessment also predicte d crawlspace cleanup value using site-specific exposure information. A sensitivity analysis on th e 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 ac tions) showed a 75 th 

### 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 accep table OU 2 lead concentration of 463 mg/kg. The probabilistic analysis for all of the data showed a 90 th 

### 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 b ackground concentration for clean fill used during remediation), the probability of a given residen ce 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 concentr ation in the yard. Th e concentration in the crawlspace had a much lower im pact on the result for EPC and crawlspace clean-up value. These results indicate that crawlspace concentrati on has relatively little c ontribution to risk from

lead at the site.

.EA Project No. 14342.26 References, Page 1 of 3 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### REFERENCES

Eagle Construction & Environmental Services, L.P. 1999. “Final Project Report, MDI Residential Area Soil Removal, Hous ton, 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, Houst on, 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, Re medial Investigation/ Feasibility Study, Many Diversified Interests, Inc. S uperfund Site, Operable Unit 3.” Prepared for EPA Region 6.

December.

EA. 2008a. “Remedial Investigation/Feasib ility Study Work Plan (Revision 02), Many Diversified Interests, Inc. S uperfund Site, Operable Unit 3, Hous ton, 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 Repor t, Remedial Investig ation/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. “Dat a Evaluation Summary Report, Operable Unit 2, Remedial Investigation and Feasibility St udy, Many Diversified Inte rests 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 Repor t for Operable Unit 2, Many Diversified Interests, Inc. Superfund Site.” July.

Texas Commission on Environmenta l Quality (TCEQ). 2007. “T exas 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.EA Project No. 14342.26 References, Page 2 of 3 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### EPA. 1995. Record of Decision, RSR Corporation Superfund Site, Operable Unit No. 1 - Residential Property, Dallas, Texas. May.

EPA. 1997. Record of Decision, Reside ntial 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 Anal ysis of Soil at Lead (Pb) Sites

. Office of Emergency and Remedial Re sponse (OERR). EP A-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/c ontaminants/lead/products.htm#ieubk

EPA. 2006. Agreed Order on Consent, Many Diversi fied Interests, Inc. Superfund Site. Docket No. 06-12-05. EPA Region 6. September.

EPA. 2007a. User’s Guide for the Integrated Exposur e 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 Statemen t of Work (Revision 01) for Remedial Investigation/Feas ibility Study, Many Diversified Intere sts, 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) fo r Chemical Contaminants at Superfund Sites. RSL Table Update. September.

Weston Solutions, Inc. (Weston). 2004. “MDI Of f-Site Properties Removal Report, Houston, Harris County, Texas.” Prepared for EPA Region 6. March.EA Project No. 14342.26 References, Page 3 of 3 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### 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.EA Project No. 14342.26 Glossary, Page 1 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Report Houston, Harris County, Texas Revision 02 

### GLOSSARY

Adenovirus

– A virus that causes upper respiratory infection.

Adverse Health Effect

– A change in body function or cell struct ure that may lead to disease or health problems.

Alveoli

– An air sac in the lung wh ere gases are exchanged.

Anthropogenic

– Of, relating to, or resulting from the in fluence of human bei ngs 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 s ubstance 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, bo dily mutations that affect cel l growth and differentiation. Cancer is characterized by an abnor mal, 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 inve stigation, is a planning tool that organizes information that already is known about a site an d 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 informa tion needed to rem ove significant unknowns from

the model. The CSM serves se veral purposes—as a planning instru ment; as a modeling and dataEA Project No. 14342.26 Glossary, Page 2 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### interpretation tool; and as a means of co mmunication among members of a project team, decision makers, stakeholde rs, and field personnel.

Confidence Interval

– A confidence interval gives an estimate d range of values that is likely to include an unknown population paramete r. This estimated range is ca lculated 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 pote ntially 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 se ts 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 nu merical values or “single point” estima tes 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 substa nce 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 relationsh ip between the magnitude of an administered, applied, or internal dose and a specific biological response. Response can be expressed as measured or observe d incidence or change in level of response, percent response in groups of subjects (or populations), or the prob ability 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 o f an effect of a chemical exposure.

Erythrocytes

– Red blood cells.EA Project No. 14342.26 Glossary, Page 3 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### Exposure – Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may be short-term (acute), of inte rmediate 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 in to contact with (or be exposed to) it. An exposure pathway has five parts: a source of c ontamination (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 exposur e (eating, drinking, breathing, or touching); and a receptor population (people poten tially 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 pers on 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 setti ng, 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 consid ered, including health risk, costs, and what

methods will work well.

Geometric Mean

– A type of mean (or average) that i ndicates 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 divi ding by the total number of valu es in a set, the numbers are multiplied and the n th 

### 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.EA Project No. 14342.26 Glossary, Page 4 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### Hazard Characterization

– A description of the potential advers e health effects attributable to a specific environmental agent, the mechanisms by wh ich agents exert their toxic effects, and the associated dose, route, dura tion, 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 cel ls that is primarily responsible for transferring oxygen from the lungs to the rest of the body. He moglobin, 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 asse ssors 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 pr esent (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 explanati on for a specified phenomenon or group of phenomena.

In Situ

– A Latin term meaning "in its original pl ace" 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 contam inant can enter the body this way.

Isopleth

– A line connecting points at which a given va riable has a specifie d constant value.

Iteration

– Repetition.

Linear Regression

– The process of fitting the best possi ble straight line through a series of points. Linear regression is often used to re duce a set of points to a simple mathematical relationship or to deduce the underl ying trends from a set of meas urements that are expected, on theoretical grounds, to fo llow a straight line.EA Project No. 14342.26 Glossary, Page 5 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### 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 s ubject of regulatory

concern and activities.

Median

– A value that is halfway through an ordered se t 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 th at 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 ever y 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. Mutati ons 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 prio rities 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 th at describes data that clusters around a mean or average value. The graph a ssociated with the norma l distribution is bell shaped, with a peak at the mean or average value.

Null Hypothesis

– A statement (represented as H

o 

### ) 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.EA Project No. 14342.26 Glossary, Page 6 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### Operable Unit

– An operable unit is a discre te 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 a ppropriate 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 exam ple, 50 percent of the data values lie below

the 50 th 

### percentile.

Pharmacokinetics

– The study of what happens to a subs tance in the body, including how the substance gets into the body, where it goes in the body, how it is cha nged 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 fo r 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 substa nce from a site over a specified period to the estimated daily exposure level, at which no a dverse 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 ra nge of possible outcomes and the likelihood of each, which often is presented as a frequency di stribution graph, thus allowing uncertainty or variability to be expressed quantitatively.

Probability

– A quantitative description of the likelihood of a particular ev ent, conventionally expressed on a scale from 0 to 1. A rare even t 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.EA Project No. 14342.26 Glossary, Page 7 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### 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 adve rse effects during a lifetime.

Remedial Action – The actual construction or implementa tion 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 fr om 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 agen ts (hazard characterization), the dose-response relationship (dose-response asse ssment), and the extent of hu man exposure to those agents (exposure assessment). The product of the risk assessment is a stat ement regarding the probability that exposed populations or individua ls 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 a ny of the identified adverse effects will occur in exposed people.

Sample – A portion or piece of a whole; a selected s ubset of a population or subset of whatever is being studied. For example, an environmen tal 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 in correctly 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 contaminan t. This estimate, usually expressed in units of proportion (of a population) affected per milli gram 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 ri sks less than 1 in 100.EA Project No. 14342.26 Glossary, Page 8 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### Standard Deviation

– A measure of variability representing an average distance of the data from the mean (or average).

Standard Error

– Standard error is the standa rd deviation of the values of a given function of the data (parameter), over all possi ble samples of the same size.

Statistical Significance

– Data is said to be statistica lly 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 pr obability that a result is not like ly to be due to chance alone.

Superfund – Federal authority, estab lished 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 he alth or welfare.

Systemic Toxicity – Systemic toxicity includes the toxic e ffects 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 harm ful effect is expected to occur.

Toxicity – Harmful biological effects caused by a ch emical, 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 pharm acokinetics to determine the relationship between the systemic exposure of a compound in experimental an imals 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 th e 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. Additi onal consideration may a l so be made if there isEA Project No. 14342.26 Glossary, Page 9 of 9 EA Engineering, Science, and Technology, Inc. April 2009

Many Diversified Interests Operable Unit 3 Remedial Investigation Houston, Harris County, Texas Revision 02 

### 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 tran sferred 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 condi tions. 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 wh ich is not normally produced or expected to be present in it, or a substance found in an organism at a higher level than expected.

# TablesTABLE 1 SUMMARY OF PROPERTIES (YARDS) ADDRESSED DURING PREVIOUS INVESTIGATIONS AND REMOVAL ACTIONS (1999 - 2006)MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3Property TypeLocated WithinModeled AirDeposition Area andEast Blower AreaLocated Outside ofModeled AirDeposition Area andEast Blower Area TotalLocated WithinModeled AirDeposition Area andEast Blower AreaLocated Outside ofModeled AirDeposition Area andEast Blower Area TotalOU 2 PropertiesSampled During2003 OU 2 RIOU 2 Properties withLead in Soil AboveCleanup Level (463mg/kg)Total No. of PropertiesRemediated During EPARemoval Actions(2003/2005/2006)Residential180352154029691333737Vacant lot9838136101020331616Public housing101000111Commercial/industrial25530000611Public use202000211Church516000533School101000111Daycare center000000000TOTAL312793915039891816060Notes:1EPAU.S. Environmental Protection Agencymg/kg Milligram per kilogramOU 2 Operable Unit 2 (Modeled Air Deposition Area and East Blower Area)RI Remedial InvestigationTNRCCTexas Natural Resource Conservation Commission (now known as the Texas Commission on Environmental Quality)Summary of Properties InvestigatedSummary of Properties Remediated during TNRCCRemoval Action (1999)Summary of OU 2 Investigation and EPA Removal Actions (2003 -2006)1OU 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 lead isopleth).TABLE 2 SUMMARY OF PROPERTY ACCESS AND SAMPLING FOR RESIDENTIAL CRAWLSPACESMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3DescriptionWithin the ModeledAir Deposition Area andEast Blower AreaOutside of the ModeledAir Deposition Area andEast Blower AreaTotalTotal No. of Residences with Accessible Crawlspaces1997206Total No. of Residences with Inaccessible Crawlspaces26026Total No. of Residences with Accessible CrawlspacesSampled During2003 OU 2 RI23 6 29Total No. of Residences with Accessible CrawlspacesSampled During2008 OU 3 RI7810 78Total No. of Residences with No Crawlspaces-Concrete Slabs18018Total No. of Residences with Access Obtained forCrawlspaces90090Total No. of Residences with Access Not Obtained forCrawlspaces1090109Notes:1One 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 kilogramOU 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 by the 0.8 gram persquare meter per year lead isopleth).TABLE 3 SUMMARY OF PROPERTY ACCESS AND SAMPLING FOR RESIDENTIAL YARDS AND HIGH-ACCESS AREASMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3Property TypeTotal No. of Residential Yards andHigh-Access Areas with AccessGranted/Secured and Sampled During2003 OU 2 RITotal No. of Residential Yardsand High-Access Areas WhereAccess Was Not Granted/SecuredDuring 2003 OU 2 RITotal No. of Residential Propertieswith Access Granted/Secured andSampled During 2008 OU 3 RITotal No. of Residential Yards andHigh-Access Areas Where Access HasNot Been Granted/Secured(2003 - 2008)Residential133531439Vacant lot3341635Public housing1 00 0Commercial/industrial6000Public use2000Church5000School1000Daycare center0 00 0TOTAL181942074Notes:EPAU.S. Environmental Protection Agencymg/kgmilligram(s) per kilogramOUOperable UnitRIRemedial InvestigationSummary of Property Access within the Modeled Air Deposition Area and East Blower AreaModeled 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 lead isopleth).Lead400 mg/kgb150.514094.638.4515LeadNE273.2NANANA15TABLE 4 SUMMARY OF SCREENING CRITERIAMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3AnalyteResidential 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)Texas‐specificMedian Backgrounda(mg/kg)0‐1inch bgs0‐6inches bgs6‐12inches bgs12‐18inches bgsScreening CriteriaaTexas Commission on Environmental Quality 2007Notes:NA not applicableNE not establishedbEPA Regional Screening Level (EPA 2008)bgs below ground surfacemg/kg milligram(s) per kilogramEPA U.S. Environmental Protection AgencyTopBottomRY-1005-0-6-U06573.64RY-1005-0-6-U106546RY-1006-0-6-U-D 06963.01RY-1006-0-6-U06962.77RY-1006-0-1-S01744.67RY-1006-0-1-U01672.98RY-1007-0-1-S011,190RY-1007-0-1-S011,155.81RY-1007-0-6-U06785.72RY-1013-0-1-S011,146.46RY-1013-0-6-U06989.06RY-1014-0-1-U01777.59RY-1014-0-1-S01622.91RY-1027-0-6-U1065326Northern half of vacant lotNotes:1Fixed laboratory sample (i.e., not X-ray fluorescence sample)bgs below ground surfaceD field duplicate samplemg/kg milligram(s) per kilogramS sieved sampleU unsieved sampleTABLE 5 LEAD CONCENTRATIONS EXCEEDING 463 MG/KG FOR OPERABLE UNIT 3 RESIDENTIAL YARDSMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3Soil Depth Interval(inches bgs)DescriptionMaximum Depth of Soilwith Lead≥463 mg/kg(inches bgs)666Sample IDMaximum LeadConcentration(mg/kg)Address Key1Entire property with occupiedsingle-family residenceEntire property with occupiedsingle-family residenceEntire property with occupiedsingle-family residenceEntire property with occupiedduplexEntire property with occupiedduplex6TABLE 6 COMPARISON OF LEAD CONCENTRATIONS IN EXTERIOR PAINT AND CORRESPONDING CRAWLSPACE SOILMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3In Situ Exterior Paint (mg/cm2)Maximum Crawlspace Soil Concentration (mg/kg)4.36278.064.254464.953.128278.062.76363.442.3775.971.978504.391.966250.431.61185.111.516335.721.284285.751.034248.561.0121166.23Notes:XRF X-ray fluorescenceXRF Lead Concentration (Operable Unit 3)AddressEPA U.S. Environmental Protection Agencymg/kg milligram(s) per kilogrammg/cm2milligram(s) per square centimeterMANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Address Key a 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 ki l Milligram per kilogram

μ g/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 1MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3

Address Key b 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

μ g/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 ACTION a

Single-family residence

Vacant lot

Page 1 of 1Address 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

Concentration b

(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 3Address 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

Concentration b

(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

10 Mean Percentage Above - Only Houses with Crawlspaces 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 3Address 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

Concentration b

(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

μ g /dL = micro g ram ( s ) p er decilite r 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 μ g/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 3Address 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 ACTION a (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 3Address 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 ACTION a (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 3Address 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 ACTION a (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

μ g/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 μ g/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 3TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14Unitless 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43fCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5Unitless 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5EFYardYard 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 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57fYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)Unitless 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5PbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg formg/kg N/A N/A N/A 1,185 1,185 1,185 1,166 1,166 1,166 N/A N/A N/A N/A N/A N/APbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kg 574 574 574 963 963 963 1,190 1,190 1,190 256 256 256 280 280 280PbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kg5.7E+02 5.7E+02 5.7E+02 9.8E+02 9.9E+02 1.0E+03 1.2E+03 1.2E+03 1.2E+03 2.6E+02 2.6E+02 2.6E+02 2.8E+02 2.8E+02 2.8E+02Notes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsRY-1026RY-1025Cage008Cage009Children 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)Greg001Greg002Greg003RY-1005RY-1006RY-1007Page 1 of 7TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14UnitlessfCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5UnitlessEFYardYard Exposure Frequency (1 - EFCrawlspace)6 Days Per Week (7 Days)6 Day / 7 Days = 0.86 (1 - EFCrawlspace)UnitlessfYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)UnitlessPbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg for 02mg/kgPbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kgPbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kgNotes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsChildren 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.430.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.50.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.570.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5504 504 504 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A374 374 374 284 284 284 242 242 242 251 251 251 155 155 1553.8E+02 3.9E+02 4.0E+02 2.8E+02 2.8E+02 2.8E+02 2.4E+02 2.4E+02 2.4E+02 2.5E+02 2.5E+02 2.5E+02 1.6E+02 1.6E+02 1.6E+02RY-1011RY-1012RY-1009RY-1003RY-1004Brin005Brin005Capr002Brin004Capr002Page 2 of 7TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14UnitlessfCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5UnitlessEFYardYard Exposure Frequency (1 - EFCrawlspace)6 Days Per Week (7 Days)6 Day / 7 Days = 0.86 (1 - EFCrawlspace)UnitlessfYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)UnitlessPbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg formg/kgPbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kgPbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kgNotes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsChildren 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.430.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.50.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.570.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5N/A N/A N/A N/A N/A N/A 138 138 138 203 203 203 N/A N/A N/A209 209 209 416 416 416 166 166 166 119 119 119 293 293 2932.1E+02 2.1E+02 2.1E+02 4.2E+02 4.2E+02 4.2E+02 1.6E+02 1.6E+02 1.6E+02 1.3E+02 1.3E+02 1.4E+02 2.9E+02 2.9E+02 2.9E+02RY-1016RY-1008RY-1017RY-1018RY-1015Brin011Prov002Capr010Capr010Brin010Page 3 of 7TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14UnitlessfCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5UnitlessEFYardYard Exposure Frequency (1 - EFCrawlspace)6 Days Per Week (7 Days)6 Day / 7 Days = 0.86 (1 - EFCrawlspace)UnitlessfYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)UnitlessPbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg formg/kgPbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kgPbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kgNotes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsChildren 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.430.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.50.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.570.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5585 585 585 530 530 530 1,094 1,094 1,094 N/A N/A N/A N/A N/A N/A290 290 290 1,146 1,146 1,146 778 778 778 532 532 532 117 117 1173.1E+02 3.3E+02 3.5E+02 1.1E+03 1.1E+03 1.0E+03 8.0E+02 8.2E+02 8.5E+02 5.3E+02 5.3E+02 5.3E+02 1.2E+02 1.2E+02 1.2E+02RY-1027RY-1028RY-1010RY-1013RY-1014Prov009Prov009Prov003Mark004Mark006Page 4 of 7TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14UnitlessfCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5UnitlessEFYardYard Exposure Frequency (1 - EFCrawlspace)6 Days Per Week (7 Days)6 Day / 7 Days = 0.86 (1 - EFCrawlspace)UnitlessfYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)UnitlessPbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg formg/kgPbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kgPbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kgNotes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsChildren 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.430.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.50.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.570.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A211 211 211 289 289 289 185 185 185 81 81 81 92 92 922.1E+02 2.1E+02 2.1E+02 2.9E+02 2.9E+02 2.9E+02 1.9E+02 1.9E+02 1.9E+02 8.1E+01 8.1E+01 8.1E+01 9.2E+01 9.2E+01 9.2E+01RY-1022RY-1023RY-1019RY-1020RY-1021Mark013Mark013Hare016Hare016Hare017Page 5 of 7TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14UnitlessfCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5UnitlessEFYardYard Exposure Frequency (1 - EFCrawlspace)6 Days Per Week (7 Days)6 Day / 7 Days = 0.86 (1 - EFCrawlspace)UnitlessfYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)UnitlessPbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg formg/kgPbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kgPbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kgNotes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsChildren 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.29 0.43 0.14 0.290.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.125 0.1250.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.71 0.57 0.86 0.710.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.875 0.875N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 443 443143 143 143 320 320 320 234 234 234 85 85 85 766 7661.4E+02 1.4E+02 1.4E+02 3.2E+02 3.2E+02 3.2E+02 2.3E+02 2.3E+02 2.3E+02 8.5E+01 8.5E+01 8.5E+01 7.6E+02 7.5E+02RY-1002(Crawlspace SurCage022RY-1024RY-1000RY-1001McLe003Hare017McLe003McLe003Page 6 of 7TABLE 9 DETERMINISTIC TIME-WEIGHTED AVERAGE SOIL LEAD CONCENTRATION FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES (VARIABLE EXPOSURE FREQUENCY)MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3EFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14UnitlessfCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5UnitlessEFYardYard Exposure Frequency (1 - EFCrawlspace)6 Days Per Week (7 Days)6 Day / 7 Days = 0.86 (1 - EFCrawlspace)UnitlessfYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)UnitlessPbSCrawlspaceComposite Crawlspace Soil Concentratione.g. 1,185 mg/kg formg/kgPbSYardHighest Near Surface Composite Yard Soil Concentration(0 to 1-inch or 0 to 6-inches)e.g. 963 mg/kg formg/kgPbSWeightedTime-Weighted Average (TWA) Soil Lead Concentration Calculated as 979 mg/kg formg/kgNotes:Equation :ParameterDescriptionExample Parameter / CalculationUnitsChildren 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 3days per week respectively). The rest of the days per week, children spend playing outdoors on the front or backyard. Children between the age of 2and 6 years spend on average 3 to 4 hours outdoors. Those waking hours not encompassed by outdoor exposure, children are assumed to spend it insidetheir residence.PbSWeighted= EFCrawlspacex [(fCrawlspacex PbSCrawlspace) + (fYardx PbSYard)] + (EFYardx PbSYard)0.430.1250.570.8754437667.5E+02rvey)Page 7 of 7MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3ParameterDescriptionExample Parameter / CalculationUnitsEFCrawlspaceCrawlspace Exposure Frequency1 Day Per Week (7 Days)1 Day / 7 Days = 0.14Unitless 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.14fCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5Unitless 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1EFYardYard 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 0.86 0.86 0.86 0.86fYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)Unitless 0.875 0.75 0.625 0.5 0.375 0.25 0.125 0PbSYardHighest Near Surface Composite Yard SoilConcentration(0 to 1-inch or 0 to 6-inches)289 mg/kg (Average for OU 2 and OU 3)mg/kg 289 289 289 289 289 289 289 289PbSWeightedTime-Weighted Average (TWA) Soil LeadConcentration463 mg/kg is Soil Clean-Up Levelmg/kg 463 463 463 463 463 463 463 463PbSCrawlspaceComposite Crawlspace Soil ConcentrationCalculated Soil Lead Preliminary Remediation Goalfor Crawlspacemg/kg1.0E+04 5.2E+03 3.5E+03 2.7E+03 2.2E+03 1.9E+03 1.7E+03 1.5E+03Notes:Equation :TWA Soil Lead Concentration of 463 mg/kgVariable Fraction of TimePbSCrawlspace= PbSWeighted- PbSYardx [(fYardx EFCrawlspace) + EFYard] / EFCrawlspacex fCrawlspaceTABLE 10 DETERMINISTIC CRAWLSPACE PRELIMINARY REMEDIATION GOALS FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES(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 of the days per week, children spend playingoutdoors 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.Page 1 of 1MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3ParameterDescriptionExample Parameter / CalculationUnitsEFCrawlspaceCrawlspace Exposure Frequency2 Days Per Week (7 Days)2 Days / 7 Days = 0.29Unitless 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29fCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5Unitless 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1EFYardYard 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 0.71 0.71 0.71 0.71fYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)Unitless 0.875 0.75 0.625 0.5 0.375 0.25 0.125 0PbSYardHighest Near Surface Composite Yard SoilConcentration(0 to 1-inch or 0 to 6-inches)289 mg/kg (Average for OU 2 and OU 3)mg/kg 289 289 289 289 289 289 289 289PbSWeightedTime-Weighted Average (TWA) Soil LeadConcentration463 mg/kg is Soil Clean-Up Levelmg/kg 463 463 463 463 463 463 463 463PbSCrawlspaceComposite Crawlspace Soil ConcentrationCalculated Soil Lead Preliminary Remediation Goalfor Crawlspacemg/kg5.2E+03 2.7E+03 1.9E+03 1.5E+03 1.3E+03 1.1E+03 9.9E+02 9.0E+02Notes:Equation :TWA Soil Lead Concentration of 463 mg/kgVariable Fraction of TimePbSCrawlspace= PbSWeighted- PbSYardx [(fYardx EFCrawlspace) + EFYard] / EFCrawlspacex fCrawlspaceTABLE 11 DETERMINISTIC CRAWLSPACE PRELIMINARY REMEDIATION GOALS FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES(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 of the days per week, children spend playingoutdoors 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.Page 1 of 1MANY DIVERSIFIED INTERESTS OPERABLE UNIT 3ParameterDescriptionExample Parameter / CalculationUnitsEFCrawlspaceCrawlspace Exposure Frequency3 Days Per Week (7 Days)3 Days / 7 Days = 0.43Unitless 0.43 0.43 0.43 0.43 0.43 0.43 0.43 0.43fCrawlspaceCrawlspace Fraction of Time2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5Unitless 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1EFYardYard 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 0.57 0.57 0.57 0.57fYardYard Fraction of Time (1 - fCrawlspace)2 Hours Per 4 Hour Day2 Hours / 4 Hours = 0.5 (1 - fCrawlspace)Unitless 0.875 0.75 0.625 0.5 0.375 0.25 0.125 0PbSYardHighest Near Surface Composite Yard SoilConcentration(0 to 1-inch or 0 to 6-inches)289 mg/kg (Average for OU 2 and OU 3)mg/kg 289 289 289 289 289 289 289 289PbSWeightedTime-Weighted Average (TWA) Soil LeadConcentration463 mg/kg is Soil Clean-Up Levelmg/kg 463 463 463 463 463 463 463 463PbSCrawlspaceComposite Crawlspace Soil ConcentrationCalculated Soil Lead Preliminary Remediation Goalfor Crawlspacemg/kg3.5E+03 1.9E+03 1.4E+03 1.1E+03 9.4E+02 8.3E+02 7.5E+02 7.0E+02Notes:Equation :TWA Soil Lead Concentration of 463 mg/kgVariable Fraction of TimePbSCrawlspace= PbSWeighted- PbSYardx [(fYardx EFCrawlspace) + EFYard] / EFCrawlspacex fCrawlspaceTABLE 12 DETERMINISTIC CRAWLSPACE PRELIMINARY REMEDIATION GOALS FOR OU 3 RESIDENTIAL YARD SOIL SAMPLES(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 of the days per week, children spend playingoutdoors 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.Page 1 of 1TABLE 13EXPOSURE POINT CONCENTRATION FORECASTMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3Model Run 1 - OU 2 and OU 3 Lead Data (mg/kg)Model Run 2 - OU 2 and OU 3 Lead Data with RA (mg/kg)10thPercentile 50thPercentile 75thPercentile 90thPercentile 10thPercentile 50thPercentile 75thPercentile 90thPercentileAnnual202398587854162267348451Winter212413595823171288382510Spring194394580832159260337435Summer198392577847162262344440Fall201401587836162267351463Notes: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 throughout the year. Theblood-lead model exposure concentration input assumes uniform exposure throughout the year. Thus the annual scenario would be the input for IEUBK modelconcentration.RA = Scheduled removal of yard soil with concentrations above the OU 3 clean-up goal of 463 mg/kg and replaced with background lead concentration of 150 mg/kg forthe Study Area; using the background value was considered more protective than the clean fill concentration of 5 mg/kg lead used during previous removal actions.TABLE 14CRAWLSPACE CLEAN-UP GOAL FORECASTMANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3Model Run 1 - OU 2 and OU 3 Lead Data (mg/kg)Model Run 2 - OU 2 and OU 3 Lead Data with RA (mg/kg)10thPercentile 50thPercentile 75thPercentile 90thPercentile 10thPercentile 50thPercentile 75thPercentile 90thPercentileAnnual08401,5852,4667421,596 2,2893,206Winter06751,0511,5966461,032 1,4422,022Spring08951,8123,0117621,839 2,7563,967Summer09051,7982,8117511,730 2,6323,684Fall07521,5542,7316731,535 2,4903,791Notes: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.ScenarioModel Run 1 10thpercentile results were negative based on an artifact of the equation (occuring when yard concentrations were over the 463 mg/kg OU 2 clean-up level)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 concentration of 150 mg/kg forthe Study Area; using the background value was considered more protective than the clean fill concentration of 5 mg/kg lead used during previous removal actions.TABLE 15 SUMMARY OF PROPERTIES ADDRESSED DURING EPA AND TNRCC REMOVAL ACTIONS (1999 - 2009)MANY DIVERSIFIED INTERESTS, INC. OPERABLE UNIT 3Property TypeWithin Modeled AirDeposition Area andEast Blower AreaOutside of ModeledAir Deposition Areaand East Blower Area TotalWithin Modeled AirDeposition Area andEast Blower AreaOutside of ModeledAir Deposition Areaand East BlowerAreaTotalWithin Modeled AirDeposition Area andEast Blower AreaOutside of ModeledAir Deposition Areaand East BlowerArea TotalWithin Modeled AirDeposition Area andEast Blower AreaOutside of ModeledAir Deposition Areaand East BlowerArea TOTALResidential402969370375058229111Vacant lot10102016016101271037Public housing000101000101Commercial/industrial000101000101Public use000101000101Church000303000303School000101000101Daycare center000000000000TOTAL5039896006060611639155Notes:EPAU.S. Environmental Protection AgencyOUOperable UnitRIRemedial InvestigationTNRCCTexas Natural Resource Conservation Commission (now known as the Texas Commission on Environmental Quality)TOTAL PROPERTIES REMEDIATED ORSCHEDULED FOR REMEDIATION(1999 - 2009)Summary of Properties Remediated during TNRCCRemoval Action(1999)Summary of OU 2 Properties Remediated duringPrevious 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 0.8Summary of OU 3 Properties Scheduled for UpcomingEPA Removal Action (2009)

# Figuress

s S

t

0

. 8

g

/ m 2

- y

e a

r 400 mg/kg2009-04-09 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:B

0

. 8

g

/ m 2

- y

e a

r 400 mg/kg2009-04-09 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)

### FID	Shape *	OBJECTID	HCAD_NUM	BLK_NUM	LOT_NUM	CONDO_FLAG	owner_name	Cent_X	Cent_Y	Address	Location_I	2008___Acc	HCAD	CS_not 52	Polygon	965184	0351330000003	 	 	0	DEMOZ HAGOS	3130718.4871	13844930.9558	3310 Baer Street	316	X	0351330000003	x 49	Polygon	967715	0221890000026	 	 	0	EVERETT WILLIE LOUISE ENSTATE OF	3134108.6904	13846221.4362	4437 Providence Street	007	X	0221890000026	x 23	Polygon	1061059	0421500000090	 	 	0	SMITH M T	3131477.1638	13846467.7353	1206 Bringhurst Street	154	X	0421500000090	x 39	Polygon	965351	0590090020006	 	 	0	COHEN JAY H	3131489.8737	13845111.9179	704 Bringhurst Street	352	X	0590090020006	x 79	Polygon	965534	0562320000004	 	 	0	DURAL ANNIE MAE	3133510.795	13845469.9104	4308 Hare Street	247	X	0562320000004	x 51	Polygon	965668	0511790100020	 	 	0	MT VIEW CHURCH OF GOD IN	3133676.0026	13844579.0135	405 Waco Street	452	X	0511790100020	x 75	Polygon	965236	0081530000015	 	 	0	CANTU IRMA	3131549.2856	13845576.1387	3605 Hare Street	444	X	0081530000015	x 61	Polygon	965226	0421500000360	 	 	0	WILLIAMS CHARLES	3132045.7001	13845713.6819	3808 Buck Street	293	X	0421500000360	x 22	Polygon	967711	0221890000036	 	 	0	THOMPSON KENDRICK J	3133852.4727	13846212.9378	4411 Providence Street	012	X	0221890000036	x 87	Polygon	1061100	0090110000007	 	 	0	TINE CLARA R	3130894.2575	13846042.1991	3407 Providence Street	086	X	0090110000007	x 74	Polygon	965229	0081530000011	 	 	0	ALBRIGHT JESSIE LEE	3131942.9187	13845707.9543	3802 Buck Street	404	X	0081530000011	x 29	Polygon	1061106	0090110000012	 	 	0	MARKMAN JACK	3131016.8358	13846109.2713	1105 Cage Street	074	X	0090110000012	x 89	Polygon	1516561	1302230010004	1	4	0	LANTERRA LLC	3130325.6908	13844666.2797	516 Bayou Street	287	X	1302230010004	x 30	Polygon	1060942	0351900000001	 	 	0	PRICE IRMA HALL ESTATE	3130683.1696	13846589.5279	1219 Gregg Street	120	X	0351900000001	x 32	Polygon	965266	0421500000405	 	 	0	PAYTON ESTELLA RUTH	3132287.502	13845629.1304	3907 Hare Street	281	X	0421500000405	x 48	Polygon	967727	0221890000006	 	 	0	COLLETT MARY B	3133851.2106	13846348.2293	4410 Sharon Street	020	X	0221890000006	x 91	Polygon	1516871	0090080000012	 	 	0	GONZALEZ VINCENT &	3131000.5815	13845314.1231	3411 Nance Street	450	X	0090080000012	x 90	Polygon	1516557	1302230010003	1	3	0	LANTERRA LLC	3130327.5867	13844629.3283	514 Bayou Street	287	X	1302230010003	x 88	Polygon	1061021	0421500000460	 	 	0	DUTTON AMANDA	3131493.3133	13846197.2627	1110 Bringhurst Street	083	X	0421500000460	x 25	Polygon	1061058	0421500000095	 	 	0	HERNANDEZ TEODORO & ISABELL	3131453.638	13846439.9178	1204 Bringhurst Street	153	X	0421500000095	x 31	Polygon	1061015	0421500000475	 	 	0	WARTEL WILLIE J	3131593.7845	13846239.87	1113 Capron Street	078	X	0421500000475	x 27	Polygon	1061056	0421500000105	 	 	0	CHEVALIER WILLIE J &	3131504.8385	13846428.4063	3605 Green Street	149	X	0421500000105	x 85	Polygon	1061039	0081500000002	 	 	0	MAENZA FRANK J	3131444.9224	13845967.6615	1016 Bringhurst Street	090	X	0081500000002	x 28	Polygon	1061105	0090110000009	 	 	0	SALAZAR LETICIA	3131017.8133	13846079.3473	1103_5 Cage Street	072	X	0090110000009	x 26	Polygon	1060943	0351900000002	 	 	0	CANADA PICKETT	3130685.6068	13846539.6029	1215 Gregg Street	121	X	0351900000002	x 24	Polygon	1061102	0090110000016	 	 	0	BURTON WOODS MARY	3130986.3453	13846027.9546	3421 Providence Street	094	X	0090110000016	x 45	Polygon	965548	0562310000022	 	 	0	JIMENES NATIVDAD	3133496.0285	13845620.5611	4301 Hare Street	241	X	0562310000022	x 69	Polygon	965575	0562330000023	 	 	0	OWENS MARY	3133469.0163	13845131.0247	4309 Coke Avenue	183	X	0562330000023	x 19	Polygon	965569	0562330000016	 	 	0	PEREZ BRUNO	3133189.0554	13845115.9756	4205 Coke Street	177	X	0562330000016	x 72	Polygon	965284	0081560000002	 	 	0	BASS JENNIE	3132760.9394	13845991.635	4108 Providence Street	040	X	0081560000002	x 63	Polygon	965255	0421500000065	 	 	0	ELLIS PAUL	3132938.3427	13845684.422	803 Press Street	311	X	0421500000065	x 73	Polygon	965308	0590090010009	 	 	0	COHEN JAY H	3131516.731	13845347.3824	3607 Nance Street	350	X	0590090010009	x 9	Polygon	965595	0511790090004	 	 	0	ALONZO ADELITA	3133239.3161	13844724.3074	4205 Cline Street	193	X	0511790090004	x 18	Polygon	965596	0511790090007	 	 	0	BROWN ALMA TATE EST PF	3133301.6818	13844727.3369	4207 Cline Street	194	X	0511790090007	x 14	Polygon	965563	0562330000009	 	 	0	HAYWARD TERRY & KINTRA	3133343.8349	13845226.6988	4222 Gunter Street	208	X	0562330000009	x 35	Polygon	965281	0081560000011	 	 	0	TORRES EDGAR &	3132765.5844	13845889.385	4109 Buck Street	301	X	0081560000011	x 80	Polygon	968481	0562330000004	 	 	0	GERMANY A J	3133539.3198	13845237.1088	4310 Gunter Street	234	X	0562330000004	x 86	Polygon	1296400	0090120000006	15	6	0	SUSTAITA JUAN PABLO	3131132.5428	13846074.7309	1104 Cage Street	073	X	0090120000006	x 68	Polygon	965353	0590090020013	 	 	0	COHEN JAY H	3131487.1132	13845172.4702	712 Bringhurst Street	353	X	0590090020013	x 53	Polygon	965588	0511790090019	 	 	0	FERNANDEZ JULIO	3133347.9344	13844829.6715	4206 Gillespie Street	271	X	0511790090019	x 8	Polygon	965561	0562330000011	 	 	0	TELLIS LAWRENCE	3133263.823	13845222.7025	4216 Gunter Street	227	X	0562330000011	x 16	Polygon	965562	0562330000010	 	 	0	MAYS TEMPEST & ADDIE M	3133303.8153	13845224.7072	4218 Gunter Street	228	X	0562330000010	x 12	Polygon	965531	0562320000021	 	 	0	ALLEN CORA F	3133456.0456	13845369.6789	4301 Gunter Street	229	X	0562320000021	x 13	Polygon	965533	0562320000022	 	 	0	GUAJARDO JESUS	3133496.6818	13845372.8023	4305 Gunter Street	231	X	0562320000022	x 83	Polygon	965524	0562320000016	 	 	0	HERNANDEZ JUAN & MARIA	3133255.7988	13845358.7169	4215 Gunter Street	213	X	0562320000016	x 46	Polygon	967718	0221890000032	 	 	0	BARNETT JEROME	3133958.7344	13846216.447	4421 Providence Street	011	X	0221890000032	x 47	Polygon	968559	0562330000027	 	 	0	CHOI YIN SOON & MEI	3133675.5914	13845131.3004	603 Waco Street	323	X	0562330000027	x 82	Polygon	1061047	0421500000110	 	 	0	BEULAH LAND COMMUNITY	3131595.6541	13846589.8535	1217 Capron Street	137	X	0421500000110	x 38	Polygon	967717	0221890000043	 	 	0	MAYHORN WILLIE D	3134008.7007	13846218.1572	4423 Providence Street	013	X	0221890000043	x 11	Polygon	965535	0562310000012	 	 	0	ELMORE ALBERT	3133182.5398	13845701.3911	4206 Buck Street	259	X	0562310000012	x 60	Polygon	1074171	0071310000002	 	 	0	CHOI YIN SOON	3133461.3109	13844988.5077	4306 Coke Street	185	X	0071310000002	x 43	Polygon	1061050	0421500000125	 	 	0	BEULAH LAND COMMUNITY	3131575.5162	13846515.2465	1211 Capron Street	162	X	0421500000125	x 56	Polygon	965265	0421500000410	 	 	0	RAINEY JOE	3132337.1964	13845631.914	3919 Hare Street	446	X	0421500000410	x 57	Polygon	965539	0562310000010	 	 	0	HINES OCIE C SR &	3133287.2979	13845705.5512	4212 Buck Street	261	X	0562310000010	x 17	Polygon	965594	0511790090021	 	 	0	HUBBARD ELTON R	3133235.6946	13844824.1924	4202 Gillespie Street	275	X	0511790090021	x 33	Polygon	965350	0590090020019	 	 	0	COHEN JAY H	3131491.5732	13845074.2784	702 Bringhurst Street	351	X	0590090020019	x 42	Polygon	1074169	0071310000007	 	 	0	CONTRERAS ANA CAROLINA	3133364.8327	13844973.861	4226 Coke Street	457	X	0071310000007	x 20	Polygon	983053	0351240000012	 	 	0	HERNANDEZ MARIO & MARMALEJO JESSICA A	3130754.1054	13845175.3807	717 Gregg Street	284	X	0351240000012	x 21	Polygon	967197	0610230090002	 	 	0	JONES ROBERT L	3134300.4005	13846535.8017	4600 Vernon Street	059	X	0610230090002	x 37	Polygon	965532	0562320000005	 	 	0	PEAVY J W JR	3133464.2293	13845463.9429	4304 Hare Street	256	X	0562320000005	x 92	Polygon	1519694	0090080000014	11	 	0	SANCHEZ TEODOLFO	3131080.9081	13845350.8057	811 Cage Street	424	X	0090080000014	x 93	Polygon	1519692	0090080000013	 	 	0	T D I GROUP INC	3131040.1925	13845316.278	3413 Nance Street	451	X	0090080000013	x 58	Polygon	967736	0221900000008	 	 	0	BARNETT JEROME	3133943.3458	13846041.0052	4420 Providence Street	056	X	0221900000008	x 84	Polygon	1061109	0090110000003	 	 	0	ARTHUR HARRY C	3130921.9967	13846167.6642	3408 Moses Street	066	X	0090110000003	x 64	Polygon	965250	0081540000005	 	 	0	ELLIS ERATUS	3132758.7335	13845750.6529	4108 Buck Street	406	X	0081540000005	x 36	Polygon	965309	0590090010010	 	 	0	COHEN JAY H	3131557.2906	13845349.7371	3611 Nance Street	286	X	0590090010010	x 66	Polygon	1061033	0350090000007	 	 	0	MC GOWAN J B	3131693.0768	13846626.1899	3702 Market Street	168	X	0350090000007	x 55	Polygon	965171	0351330000001	 	 	0	TDI GROUP INC	3130769.0769	13844957.6106	3314 Baer Street	289	X	0351330000001	x 50	Polygon	965526	0562320000017	 	 	0	STINSON MALINDA	3133295.8936	13845361.12	4219 Gunter Street	226	X	0562320000017	x 10	Polygon	965766	0511780080009	 	 	0	CHOI YIN S & MEI	3133661.809	13844842.4229	515 Waco Street	324	X	0511780080009	x 40	Polygon	965174	0351330000009	 	 	0	ROBERSON MARGARET LOUISE	3130775.7709	13844812.1976	601 Gregg Street	283	X	0351330000009	x 76	Polygon	967735	0221900000012	 	 	0	MAYHORN WILLIE D	3134018.3216	13846043.5777	4422 Providence Street	017	X	0221900000012	x 34	Polygon	965559	0562330000014	 	 	0	JORDON SONJA	3133142.9658	13845216.4709	4202 Gunter Street	211	X	0562330000014	x 41	Polygon	1074168	0071310000009	 	 	0	EPPS GERALDINE VAUGHN	3133264.9065	13844968.5783	4211 Gillespie Street	269	X	0071310000009	x 71	Polygon	1061132	0090090000004	 	 	0	BROOKS BESSIE MAY	3130906.1027	13845677.9125	3406 Buck Street	067	X	0090090000004	x 81	Polygon	983554	0090050000014	 	 	0	CURRENT OWNER	3131019.7545	13844700.9089	3410 Gillespie Street	290	X	0090050000014	x 6	Polygon	965310	0590090010011	 	 	0	COHEN JAY H	3131606.9561	13845352.0016	3615 Nance Street	355	X	0590090010011	x 5	Polygon	965316	0590090010003	 	 	0	COHEN JAY H	3131553.1306	13845449.0259	3610 Hare Street	356	X	0590090010003	x 4	Polygon	965315	0590090010004	 	 	0	COHEN JAY H	3131602.7923	13845451.6805	3614 Hare Street	357	X	0590090010004	x 77	Polygon	965520	0562320000013	 	 	0	SALINAS T M	3133135.5673	13845352.2277	4201 Gunter Street	212	X	0562320000013	x 62	Polygon	965667	0511790100031	 	 	0	MT VIEW CHURCH GOD CHRIST	3133637.2847	13844627.8931	4310 Cline Street	427	X	0511790100031	x 67	Polygon	965237	0081530000014	 	 	0	CANTU PEDRO JR	3131500.2549	13845563.5065	3603 Hare Street	443	X	0081530000014	x 2	Polygon	965336	0090060000001	 	 	0	WILLIAMS VICTORIA	3131075.8645	13844919.7726	613 Cage Street	418	X	0090060000001	x 7	Polygon	965369	0090070000011	 	 	0	CERVANTS JOSE GUADALUPE	3131064.2533	13845161.2328	715 Cage Street	422	X	0090070000011	x 3	Polygon	965368	0090070000001	 	 	0	CORRETHERS MARRIET	3131061.304	13845211.001	717 Cage Street	423	X	0090070000001	x 95	Polygon	1542284	1294850010001	 	1	0	INTOWNHOMES LTD	3131046.3417	13844820.5058	4317 Gillespie Street	322	X	1294850010001	x 65	Polygon	965527	0562320000018	 	 	0	WHITE ETHYLEAN W	3133336.0256	13845362.9365	4223 Gunter Street	225	X	0562320000018	x 15	Polygon	965767	0511780080003	 	 	0	ADAMS WILLIE	3133588.3812	13844814.1743	4312 Gillespie Street	438	X	0511780080003	x 0	Polygon	965364	0090070000006	 	 	0	TDI GROUP INC	3130893.9987	13845077.1453	702 Gregg Street	440	X	0090070000006	x 70	Polygon	1074172	0071310000013	 	 	0	CHOI YIN SOON	3133408.5185	13844976.2014	4230 Coke Street	187	X	0071310000013	x 78	Polygon	965355	0590090020001	 	 	0	COHEN JAY H	3131484.6522	13845239.8991	718 Bringhurst Street	354	X	0590090020001	x 59	Polygon	965241	0421500000385	 	 	0	TINAJERO JOSE LUIS	3132283.2994	13845727.0628	3910 Buck Street	405	X	0421500000385	x 1	Polygon	1409878	0090070000003	 	 	0	TDI GROUP INC	3130988.7904	13845182.4791	3410 Nance Street	449	X	0090070000003	x 94	Polygon	1516549	1302230010001	1	1	0	LANTERRA LLC	3130331.5171	13844552.6787	510 Bayou Street	287	X	1302230010001	x 96	Polygon	1542286	0090060000008	 	 	0	MENDEZ LUZ	3131004.6463	13844840.7311	3409 Gillespie Street	430	X	0090060000008	x 54	Polygon	965591	0071310000010	 	 	0	VAUGHN ALFRED & GERALDINE	3133172.5777	13844963.6159	4205 Gillespie Street	272	X	0071310000010	x 44	Polygon	965545	0562310000021	 	 	0	ROUGEAU DAISY L	3133424.8513	13845617.1136	4225 Hare Street	240	X	0562310000021	x FID	Shape *	OBJECTID	HCAD_NUM *	BLK_NUM	LOT_NUM	CONDO_FLAG	owner_name	address	Cent_X	Cent_Y 4327	Polygon	1061043	0350090000002	 	 	0	LINDSEY MARION P JR	1218 BRINGHURST ST	3131444.164	13846609.5786



# §  ̈ ¦

10 

# §  ̈ ¦

10

t

0

. 8

g

/ m 2

- y

e a

r 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 389 mg/kg CS-1068 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/kg2009-04-09 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/m 2 -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, TexasB

r

i
n

g

h

u

r

s

t

S

t C a g

e

S

t P

r

e

s

s

S

t 

### 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/kg2009-04-09 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 soilInput ParametersGraphical Distribution Probability –Percentage (%) of Children Under 7 YearsIndoor Air Lead ConcentrationOld with Elevated Blood Lead Levels ofConcern (> 10 μg/dL) from Lead Exposure(e.g., Lead in Soil)Outdoor Air Lead ConcentrationPerform Integrated ExposureU t k BiKi ti (IEUBK)(Percentage of Outdoor) = 0.30(Model Default)AirExample Result – If Soil Concentration is= 0.1 μg/m3(Model Default)UptakeBio-Kinetic(IEUBK)Lead Modeling for Each AreaAirTime Spent Outdoors, VentilationRate,and LungAbsorption Werep463 mg/kg, then 7.8% of Children 6 to 84Months (7 Years) are Predicted to HaveBlood Lead Level > 10 μg/dL, gpModel DefaultsDietaryDietary Lead Intake WereConsistent with OU2 Model DefaultsWater Consumption wereModel Defa ltsIEUBK L d M d liLead Concentration in DrinkingWater = 4 μg/L (Model Default)ModelDefaultsWaterC Si C iIEUBKLeadModelingof Area Soil to EvaluateLead Action Level of463mg/kgOutdoor Soil Lead Level =Soil/Dust Ingestion Weighting Factor(Percent Soil) = 45 (Model Default)The Lead Clean-Up Goalwas 500 mg/kg. The AverageRelative Standard Deviation of the MeasuringInstrument (X-Ray Fluorescence) was 37 mg/kg. TheCompareSiteConcentrationAgainst the Lead Action Levelof 463 mg/kg for Each AreaGreater Than63 g/ gOutdoorSoilLeadLevel=Area-Specific Maximum SoilConcentration (μg/g)SoilAmount of Soil/Dust Ingested DailyAction Level was 463 mg/kg(Lead Clean-Up Goal –Average Relative Standard Deviation ). The ActionLevel for Lead in Soils was Determined to be Protectiveof HumanHealthBased on IEUBK Modeling of DataLead Action Levelof 463 mg/kg?AmountofSoil/DustIngestedDailyWere Model DefaultsMother’s Blood LeadConcentrationofHumanHealthBasedonIEUBKModelingofDataCollected from Other EPA Region 6 Superfund Sites.MaternalCat Childbirth = 2.5 μg Lead per dL(Model Default)YesNoAlternateAlternate Lead Intake – NoneIdentified (Model Default)Risk Management DecisionArea Subject to Remedial Action if Percentage ofRisk Management DecisionArea Not S bject to Remedial Action if PercentageF ti P i / T t l A iblTotal Percent Accessible = 30% Soil,30% Dust, 50% Water, 50% Diet,and 0% Alternate (Model Defaults)GI/BiAreaSubjecttoRemedialActionifPercentageofChildren 6 to 84 Months (7 Years) with PredictedBlood Lead Levels > 10 μg/dL is UnacceptableAreaNotSubjecttoRemedialActionifPercentageof Children 6 to 84 Months(7 Years) with PredictedBlood Lead Levels > 10 μg/dL is AcceptableFractionPassive/TotalAccessible= 0.2 ( Model Default)GI/BioHalf Saturation Level = 100 μg /dayManyDiversified Interests, Inc. Superfund SiteFigure9.Integrated Exposure Uptake Bio-Kinetic(IEUBK)(Model Default)EA Engineering,Science,and Technology,Inc.y pHouston, Harris County, Texasgg pp( )Lead Model Process Flow Chartg g, ,gy,Project Number - 1434226

# Appendix A

Access Agreements

# Appendix B

Summary of Qualitative Door-to-Door Surveys

# Appendix C

Residential Property Sketches

# Appendix D

Analytical Data Summary Tables

Table D-1 Analytical Data Summ ary – Lead in Soil (2003 – 2008) Table D-2 Analytical Data Summary – Residential Yard Soil (2003 – 2008) Table D-3 Analytical Data Summary – Residential Crawls pace Soil (2003 – 2008) Table D-4 Analytical Data Summar y – 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

# Appendix D-9

Residence Identifiers and Address Keys

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Blanche Kelso Bruce Elementary School Bruc001

Page 1 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 2 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 3 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 4 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 5 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address

Page 6 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

3600 Providence Street

Page 7 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 8 of 9 

### CONFIDENTIAL INFORMATION

### TABLE D-9

RESIDENCE IDENTIFIERS AND ADDRESS KEYS

Address Address Key

Page 9 of 9 

### CONFIDENTIAL INFORMATION

# Appendix E

Results of Statistical Analysis of Soil DataXRF = 0.95*Lab + 9.3R2 = 0.93p < 0.00180010001200

m g/kg)Figure E-1 Linear Regression of Collocated XRF and Laboratory DataOb d0200400600020040060080010001200

XRF Lead ( mLaboratory Lead (mg/kg)ObservedTrendline1:1 Reference LineTABLE E-1REGRESSION ANALYSIS OF LABORATORY AND XRF LEAD DATAMANY DIVERSIFIED INTERESTS SUPERFUND SITE OPERABLE UNIT3Regression StatisticsMultiple R 0.96R Square0.93Adjusted R Square0.93Standard Error58.25Observations73Analysis of VariancedfSSMSF Significance FRegression1 3072510.74 3072510.74 905.560.000Residual71 240898.09 3392.93Total72 3313408.83Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Interceptα(mg/kg)9.309.890.940.35-10.42 29.02Slopeβ0.950.03 30.090.000.891.02Notes: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 fluorescenceFigure E2 Least Trimmed Squares (LTS) Linear Regression of Sieved and Unsieved Sample Results for2500FigureE-2LeastTrimmedSquares(LTS)LinearRegressionofSievedandUnsievedSampleResultsforLead in Yard Samples20001500

d (mg/kg)Ob dUnsieved=1.07*Sieved‐28.7R2=91%p<0.00011000

U nsieved Soil LeaObservedLTS Trendline1:1 Reference Line500

U005001000150020002500Sieved Soil Lead (mg/kg)TABLE E-2REGRESSION ANALYSIS OF SIEVED & UNSIEVED SAMPLE RESULTS IN YARD SAMPLESMANY DIVERSIFIED INTERESTS SUPERFUND SITE OPERABLE UNIT 3Regression StatisticsR Square0.88Observations28CoefficientsStandard Error Lower 95%Upper 95%Interceptα(mg/kg)-28.6827.86-83.2825.91Slopeβ1.070.060.951.18R = coefficient of determinationFigure E3 Linear Regression of Sieved and Unsieved Sample Results for Lead in Crawlspace Samples2500FigureE-3LinearRegressionofSievedandUnsievedSampleResultsforLeadinCrawlspaceSamples2000Unsieved =1 00*Sieved+14 71500

d (mg/kg)Ob dUnsieved=1.00 Sieved+14.7R2=96%p<0.00011000

U nsieved Soil LeaObservedLTS Trendline1:1 Reference Line500

U005001000150020002500Sieved Soil Lead (mg/kg)Regression StatisticsR Square 0.96Observations 22CoefficientsStandard ErrorLower 95%Upper 95%Interceptα(mg/kg)14.7326.26-36.7366.19Slopeβ1.000.050.901.10R = coefficient of determinationREGRESSION ANALYSIS OF SIEVED & UNSIEVED SAMPLE RESULTS IN CRAWLSPACE SAMPLESMANY DIVERSIFIED INTERESTS SUPERFUND SITE OPERABLE UNIT 3TABLE E-3Yard = 0.51*Crawlspace + 135R2 = 0.31p < 0.00180010001200

m g/kg)Figure E-4 Linear Regression of SievedCrawlspace and Sieved Yard Sample ResultsOb d0200400600020040060080010001200

Yard Lead ( mCrawlspace Lead (mg/kg)ObservedTrendline1:1 Reference LineTABLE E-4REGRESSION ANALYSIS OF SIEVED CRAWLSPACE AND SIEVED YARD LEAD DATAMANY DIVERSIFIED INTERESTS SUPERFUND SITERegression StatisticsMultiple R 0.55R Square0.31Adjusted R Square0.29Standard Error217.30Observations56Analysis of VariancedfSSMSF Significance FRegression1 1127442.03 1127442.03 23.880.0000Residual54 2549790.99 47218.35Total55 3677233.02Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Interceptα(mg/kg)135.4655.072.460.0225.06 245.86Slopeβ0.510.104.890.000.300.72Notes: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

### FIGURE E-5

LINEAR REGRESSION ANALYSIS OF LEAD CONCENTRATIONS FOR EXTERIOR

PAINT AND SIEVED/UNSIEVED SOIL SA MPLES 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 800LeadConcentrationinExteriorPaint(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 800ExteriorPaint(mg/cm2)

Crawlspace Soil (mg/kg)

### 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 3500LeadConcentrationinExteriorPaint(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 2500ExteriorPaint(mg/cm2)

Crawlspace Soil (mg/kg)

# Appendix F

Fixed Laboratory Data Packages

Appendix F-1 EPA Region 6 La boratory Data Package(s) Appendix F-2 Aerotech Environm ental 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

# Appendix G

Electronic Data (on deliverable compact disc)

Microsoft Access Database Photographs