Understates     Office of             EPA 747-8-95-C
Environment Protection ; Prevention, Pesticides, ar#l Toxic $ybstซnce$ • -- •-.
Agency	  = 71Q1     	' •
Lead-Based Paint
Abatement and Repair
and Maintenance Study
in Baltimore;
Pre-interventiori Findings
                             1

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                                                         EPA 747-R-95-012
                                                               August 1996
               LEAD-BASED PAINT ABATEMENT AND
                REPAIR AND MAINTENANCE STUDY
                          IN BALTIMORE:
                  PRE-INTERVENTION FINDINGS
                      Technical Programs Branch
                    Chemical Management Division
                Office of Pollution Prevention and Toxics
           Office of Prevention, Pesticides, and Toxic Substances
                 U.S. Environmental Protection Agency
                          401 M Street, SW
                       Washington, DC 20460
                         U.S. Environmental Protection Agency
                         Region 5, Library (PL-12J)
Recycled/Recyclable • Printed with Vegetable Based Inks on Recycled Paper (20% Postconsumer)

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The material in this document has been subject to Agency technical and policy review
and approved for publication as an EPA report.  Mention of trade names, products,
or services, does not convey, and should not be interpreted as conveying, official EPA
approval, endorsement, or recommendation.

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                         CONTRIBUTING ORGANIZATIONS
       The study described in this report was funded by the U.S. Environmental Protection Agency
(EPA).  The study was managed by EPA and conducted collaboratively by several organizations
under contract to EPA. Each organization's responsibilities are listed below.
                        Kennedy Krieger Research Institute (XKRD

       KKRI was primarily responsible for the overall design and conduct of this study, including
the field, laboratory and data analysis activities, and the preparation of this report.
                                Battelle Memorial Institute

       Battelle managers and staff provided technical and administrative support during the planning
phase  of the study including the planning, conduct and reporting of the pilot field study, the
compilation of the Quality Assurance Project Plan for the main study, and the initiation of data
collection.
                               Midwest Research Institute

       Midwest Research Institute had substantive input to the Quality Assurance Project Plan and
provided sampling and analysis support in the planning and pilot phases of the study.
         Maryland Department of Housing and Community Development (MDDHCD)
MDDHCD reserved loan funds from a special residential lead paint abatement loan program to
finance the Repair & Maintenance interventions in this study.
                           US Environmental Protection Agency

The U.S. Environmental Protection Agency (EPA) was responsible for managing the study, for
providing technical oversight, guidance and direction, and for overseeing the peer review and
finalization of the report.   The EPA Project Leader was Benjamin S. Lim.  The EPA Work
Assignment Managers were Benjamin S. Lim and Brad Schultz. The EPA Project Officers were Phil
Robinson and Jill Hacker. Cindy Stroup was the Branch Chief of the Technical Programs Branch
(TPB) who initiated this study and provided valuable input. Special Acknowledgment is given to
Darlene Watford, the Acting Methods Section Chief, for her careful review and input.
                                         iii

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                                 CONTENTS

EXECUTIVE SUMMARY	 viii

1.0 INTRODUCTION	1
      1.1    Report Objectives	1
      1.2    Purpose Of The R&M Study	1
      1.3    Peer Review	2

2.0 CONCLUSIONS	   5
      2.1    Environmental Lead	5
      2.2    Correlations Between Environmental Variables	7
      2.3    Blood Lead  	7

3.0 QUALITY ASSURANCE  	8
      3.1    System Audit 	8
      3.2    Data Audit	8
      3.3    Performance  Audit	8

4.0 STUDY DESIGN AND SAMPLE COLLECTION PROCEDURES  	13
      4.1    Overview Of Study Design	13
      4.2    Repair & Maintenance Interventions	15
      4.3    Recruitment And Enrollment  	16
      4.4    Selection Criteria For Houses And Children	17
      4.5    Characteristics Of Study Houses	18
      4.6    Sample Collection Procedures 	19

5.0 LABORATORY ANALYSIS PROCEDURES	23

6.0 DATA PROCESSING AND STATISTICAL ANALYSIS PROCEDURES	24
      6.1    Data Processing	24
      6.2    Data Summary	24
      6.3    Statistical Analysis Procedures	25

7.0 RESULTS 	31
      7.1    Demographics  	31
      7.2    Blood Lead  	34
      7.3    Environmental Lead	34
      7.4    Comparison of Study Houses And Excluded Houses  	53
      7.5    Correlations Among Environmental Lead Variables 	60
      7.6    Correlations Between Blood Lead And Environmental Lead	65

8.0 REFERENCES	69

APPENDDC: Floor Plans of Two Typical Study Rowhouses	72

                                     iv

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                                      TABLES
Table I



Table H


Table m

Table 1

Table 2

Table 3


Table 4

Table 5

Table 6

Table 7

Table 8


Table 9


Table 10

Table 11

Table 12


Table 13
Descriptive Statistics and Tolerance Limits For Percent Recovery For
SRM And Spiked Samples and Percent Differences Between Spiked
And Spike Duplicate Samples  	
10
Descriptive Statistics And Tolerance Limits For Percent Recovery For
ICV and CCV  	11

Descriptive Statistics For Field Blanks And Method Blanks  	12

Data Collection Plan	14

Selected Characteristics Of Houses By Study Group	19

Distribution Of Percent Of Individual Samples Of Carpet Making Up
Composite Dust Samples By Study Group And Story	21

Types Of Field Samples  	22

Summary Of Laboratory Procedures	23

Numbers Of Houses And Children By Study Group 	26

Reasons For Exclusion Of Candidate R&M Houses 	27

Types And Numbers Of Samples Collected And Analyzed For Lead
As A Part Of The Initial Campaign	28

Types And Numbers Of Samples Collected By Study Group
As A Part Of The Initial Campaign	29

Selected Demographic Characteristics Of Residents By Study Group	33

Descriptive Statistics For Blood Lead Concentrations By Group	33

Descriptive Statistics For Dust Lead Concentrations By Surface Type
And Study Group   	46

Descriptive Statistics For Dust Lead Loadings By Surface Type
And Study Group	47

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                               TABLES (Continued)
Table 14


Table 15


Table 16


Table 17

Table 18

Table 19


Table 20


Table 21


Table 22

Table 23

Table 24

Table 25



Table 26
Descriptive Statistics For Dust Loadings By Surface Type
And Study Group	48

Rank Of Geometric Mean Lead Concentrations And Lead Loadings
By Surface Type  	51

Descriptive Statistics For Overall Dust Lead Concentrations,
Dust Lead Loadings, And Dust Loadings By Study Group   	52

Descriptive Statistics For Soil Lead Concentrations By Study Group  	56

Descriptive Statistics For Water Lead Concentrations By Study Group	56

Comparison Of Mean Dust Lead Concentrations In The 75 R&M Houses
To The 27 Excluded R&M Candidate Houses  	57
Comparison Of Mean Dust Lead Loadings In The 75 R&M Houses
To The 27 Excluded R&M Candidate Houses  	
Comparison Of Mean Dust Loadings In The 75 R&M Houses
To The 27 Excluded R&M Candidate Houses  	
58
59
Correlations Between Environmental Dust Lead Concentrations	62

Correlations Between Environmental Dust Lead  	63

Correlations Between Environmental Dust Loadings 	64

Correlations Between Dust Lead Concentrations, Dust Lead Loadings,
And Dust Loadings And Blood Lead Concentrations Of The Youngest
Child Per Household In Continuing And Excluded Houses	67
Correlations Between Dust Lead Concentrations, Dust Lead Loadings,
And Dust Loadings And Blood Lead Concentration Of All Children In
Continuing And Excluded Houses	
                                                                                68
                                        VI

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                                     FIGURES


Figure 1:     Temporal Relationship Of Blood Collection To Environmental Sampling	32

Figure 2:     Blood Lead Concentrations By Study Group At Initial Campaign	35

Figure 3:     Geometric Mean Dust Lead And Soil Lead Concentrations By
             Sample Type And Study Group 	37

Figure 4:     Geometric Mean Dust Lead Loadings By Surface Type And Study Group .... 38

Figure 5:     Geometric Mean Dust Loadings By Surface Type And Study Group  	39

Figure 6:     Lead Concentrations For Each Surface Type By Study Group  	40

Figure 7:     Lead Loading For Each Surface Type By Study Group  	41

Figure 8:     Dust Loadings For Each Surface Type By Study Group	42

Figure 9:     Lead Concentrations For Each Study Group By Surface Type  	43

Figure 10:    Lead Loadings For Each Study Group By Surface Type	     44

Figure 11:    Dust Loadings For Each Study Group By Surface Type	45

Figure 12:    Overall Weighted Lead Concentrations, Lead Loadings, and
             Dust Loadings By Study Group 	50

Figure 13:    Soil Lead Concentrations By Study Group	54

Figure 14:    Water Lead Concentrations By Study Group 	55

Figure 15:    Scatterplot Matrix Between Environmental Lead Concentrations 	61

Figure 16:    Scatterplot Comparisons Of Blood Lead Concentration And
             Environmental Lead Loadings And Concentrations By Surface	66
                                       VII

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                               EXECUTIVE SUMMARY
       The Lead-Based Paint Abatement and Repair and Maintenance (R&M) Study is a longitudinal
study of housing intervention strategies designed to reduce children's exposure to lead in paint and
in settled dust in their homes. The R&M study is design to characterize and compare the short-term
(2 to 6 months) and longer-term (12 to 24 months) efficacy of comprehensive lead-paint abatement
with less costly and potentially more cost-effective R&M interventions designed to reduce children's
exposure to lead in residential paint and dust. The R&M may provide a practical means of reducing
exposure for future generations of children who will occupy lead-painted housing.  This study targets
low-income housing where children are at high risk.

       The initial campaign provides pre-intervention baseline data for the study of changes in lead
concentration in children's blood and in  settled house dust associated with three levels of R&M
interventions. R&M Level I includes the following elements: wet scraping of peeling and flaking
lead-based paint on interior surfaces; limited repainting of scraped surfaces; wet cleaning with a tri-
sodium phosphate detergent (TSP) and vacuuming with a high efficiency paniculate air (HEPA)
vacuum to the extent possible in an occupied house; the provision of an entryway mat; the provision
of information to occupants and owners; and stabilization of exterior surfaces to  the extent possible
given the budget cap.  R&M Level Et  interventions include all elements in  Level I plus  floor
treatments to make them smooth and more  easily cleanable and in-place window and door treatments
to reduce abrasion of lead painted surfaces.  R&M Level HI interventions include all of the elements
in Levels I and n and window replacement and encapsulation of exterior window trim with aluminum
coil stock as the primary window treatment, the encapsulation of exterior door trim with aluminum,
and more durable floor and stairway treatments.  All R&M study households receive cleaning kits for
their own wet cleaning efforts. The kits include a bucket, sponge mop, a replacement sponge mop
head, sponges, a TSP cleaning agent, and the EPA brochure entitled "Lead Poisoning and Your
Children."

       This report is based on the initial data collection campaign, which was conducted between
January 1993 and November 1994.  The baseline data are cross-sectional in nature and complement
another cross-sectional study of lead-contaminated house dust and children's blood lead concentration
conducted in Rochester, New York.1  The main conclusions and findings of this report are as
follows:

 •     Enrollment and data collection goals were attained from five study groups: houses designated
       for the three R&M interventions (Levels I through ID), previously abated control houses that
       received comprehensive abatement in the past, and modern urban control houses built after
       1979, which are presumably free of lead-based paint.  A total  of 107 houses with 140
       children were studied.

 •     Geometric mean blood lead concentrations group were:  R&M Level I, 10 ug/dL; R&M
       Level n, 14 ug/dL;  R&M Level DL, 14 |ig/dL; previously abated, 13 ug/dL; and modern
                                         viii

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       urban, 5 ug/dL.  Blood lead concentrations were found to be statistically significantly lower
       in children within the modern urban group as compared to the other groups.

•      Weighted measures of dust lead concentrations within an entire house were nearly two orders
       of magnitude higher in R&M houses (Levels I to IE:  19,000, 14,400 and 17,500 ug/g,
       respectively) than in modern urban houses (235 ug/g). Differences were larger for lead
       loadings (R&M Levels I to m, 16,600,24,000 and 47,500 jig/ft2, respectively; modern urban
       houses, 83 ug/ft2).  Previously abated houses had intermediate lead concentrations (2,400
       ug/g) and loadings (900 ug/ft2). In these houses the geometric mean lead loadings for floors
       and window sills, but not window wells, remained at or below HUD's interim clearance
       standards (100, 500, and 800 ug/ft2, respectively).

•      Children's blood lead concentrations were significantly correlated with lead levels in house
       dust from entryway and six types of interior surfaces (correlations ranging from r=.27 to .64).
       Lead loadings and concentrations in dust from the various surface types were moderately to
       highly correlated with each other.

•      Statistically significant differences were not found between R&M groups at the baseline in
       terms of blood lead concentration, environmental lead levels, and population demographics;
       however, lead levels tended to be highest in vacant R&M Level HI houses, lowest in occupied
       R&M Level I houses, and intermediate in R&M Level n, which was a mix of vacant and
       occupied houses.

•      No evidence was found for selection bias when R&M study houses were compared to houses
       that were considered for the study but later rejected for reasons explained herein.

 •     Laboratory performance and data quality objectives were met.

       Future reports  on the R&M  study  will include  longitudinal data from multiple post-
intervention sampling campaigns to be conducted during a two-year follow-up period.
                                           IX

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 1.0  INTRODUCTION

 1.1    Report Objectives

       The Lead-Based Paint Abatement and Repair & Maintenance (R&M) Study  in Baltimore is
 a longitudinal study of housing intervention strategies designed to reduce children's exposure to lead
 in paint and in settled dust in their homes. This report is based on the initial data collection campaign,
 which was conducted between January 1993 and November 1994.  The initial campaign provides pre-
 intervention baseline data for the study of changes in lead concentration in children's blood and in
 settled house dust associated with three levels of R&M interventions.  These baseline data are cross-
 sectional in nature and complement another cross-sectional study of lead-contaminated house dust
 and children's blood lead concentration conducted in Rochester, New York.1  Future reports on the
 R&M study will include longitudinal data from multiple post-intervention sampling campaigns  to be
 conducted during a two-year follow-up period.  The objectives of this report on the initial campaign
 are as follows:

 •     Describe the study objectives, design, and methodologies which are explained in detail in the
       Quality Assurance Project Plan.2

 •     Present descriptive statistics on baseline demographic, environmental, and biological data for
       the five  groups of study houses, i.e., houses designated for R&M intervention Levels I
       through  m, modern urban control houses built after 1979,  and previously abated control
       houses that received comprehensive abatement in the past, and the residents of these houses.
       The study includes a total of 107 houses and 140 children.

 •     Investigate potential selection bias by comparing the study houses designated for R&M
       interventions to houses that were considered for study but rejected for reasons explained
       herein.

 •     Assess the correlations between the lead levels in various types of environmental samples and
       between  concentrations of lead in children's blood and these environmental samples.

 •     Report on compliance with data quality objectives and performance on laboratory quality
       control samples.

 1.2    Purpose Of The R&M Study

       Past studies have documented the  short-term (2 to 6 months) and longer-term (12 to  24
months) effectiveness of comprehensive approaches to residential lead paint abatement.3'4 The R&M
study is designed to characterize and compare the short-term and longer-term efficacy of less costly
and potentially more cost-effective R&M intervention strategies for reducing children's exposure to
lead  in residential paint and settled house dust.  This research is important because house dust and
residential paints containing lead have been identified as major sources of lead in U.S. children.5"9
Exposure occurs  primarily via the hand-to-mouth route of ingestion.6'10"13  Families with children less
than seven years of age occupy approximately 10 million of the 57 million privately owned and

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occupied U.S. housing units which are estimated to contain some lead-based paint.14 Children living
in the nearly 4 million houses with deteriorating paint and elevated dust lead levels are at highest risk
of exposure.14 Given the extent and potential costs of remedying the lead abatement problem in U.S.
housing, the preventive R&M approach may provide a practical means of reducing exposure for
future generations of children who will continue to occupy housing containing lead paint.  This study
represents the first systematic examination of the R&M approach.

       The research goal of the R&M study is to contribute to the existing scientific bases needed
to develop a standard of care for lead-painted houses through the analysis of environmental and
biological data from a longitudinal intervention study. Specific study objectives are as follows:

•      Measure and compare the short-term and longer-term changes of lead concentration and
       loading in settled house dust and in children's blood lead concentrations associated with R&M
       intervention Levels I to HI with houses that  had undergone previous comprehensive
       abatement, as well as a group of modern urban houses presumably free of lead-based paint.

•      Evaluate methodologies for the collection and analysis  of lead in residential dusts, including
       wipe and cyclone methods.  (This objective has been addressed in previous reports.15"17)

•      Characterize the nature of the relationship between lead in children's blood and settled house
       dust.

1.3     Peer Review

       The draft report on the initial data collection campaign was reviewed by three independent
external reviewers.  A summary of their comments is presented below. Responses to comments are
reflected in the report.

1.      One reviewer commented that the report assumed that the reader was familiar with the study
and recommended that the text be revised to provide more  of an introduction.  The report was
reorganized to provide additional information (background, purpose, design, and methods) prior to
the presentation of the findings.

2.      Reviewers  commented that a more detailed description was needed  of the features and
characteristics of the housing stock that was sampled in the intervention and control groups. It was
pointed out that differences in housing characteristics may influence how dust travels into and within
a dwelling and that these differences among the three R&M groups might confound  later results in
the post-intervention phase. Based on these comments, section 2.5 on housing characteristics was
added to the report showing that study houses were generally similar in terms of characteristics that
might be expected to influence patterns of dust movement into and within a house  (i.e., overall house
size, number of windows, house type and design,  condition, degree of setback from the street, and
the  presence of porches and yards).  All  five groups of study  houses are primarily two-story
rowhouses, which are common in Baltimore.

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3.     A related comment was made concerning the size of the group of modem urban control
houses built after 1979 and their apparent location in neighborhoods with different ambient dust lead
levels than the other groups.  Additional text was added to the report explaining that the planned
sample sizes of the two control groups were reduced from 25 to 16 houses each, due to reductions
in the scope and funding of the project as originally planned.  The number of control houses was
reduced rather than the number of R&M houses because the former (and in particular the modern
urban houses) were expected to have less inter-house variability with respect to both blood lead and
dust lead.  This assumption was borne out in the study findings.  Furthermore, when the sample sizes
were reduced, only houses in clusters of urban houses built after 1979 were included (as opposed to
scattered-site housing) as the control group containing no lead paint because we expected this type
of housing to reflect the lowest residential and ambient lead levels in the urban environment.  While
the study did  not include street or playground dust, which would have been useful in comparing
ambient lead levels, differences in lead levels in drip-line soil and exterior entryways between groups
provided some evidence that the modern urban group, as anticipated, did differ from the other four
study groups in terms of ambient lead levels.

4.     A reviewer asked about the criteria for determining the need for additional cleanups/repairs
in the R&M  houses  during the post-intervention follow-up  period.   The need  for  further
cleanups/repairs during the entire follow-up period will be determined by a comparison of the follow-
up dust lead loadings and blood lead concentrations in children to their corresponding levels prior to
intervention (see section 4.1).

5.     One reviewer asked  whether the eligibility criterion for  R&M houses regarding pre-
intervention dust lead loadings was based on geometric mean lead loadings exceeding clearance
loadings or a certain proportion of samples exceeding clearance loadings. Eligibility is based on
houses having samples from a minimum of three locations with dust lead loadings that  exceed
Maryland's interim post-abatement clearance levels (i.e., 200 jig/ft2 for floors, 500 ug/ft2 for window
sills, and 800  |ig/ft2 for window wells). Since seven or eight interior dust samples were collected
from each house from these three surfaces, then a minimum of 38 percent (3/8) to 43 percent (3/7)
of the interior dust samples needed to exceed clearance levels in order for a house to qualify. Half
or more of the dust samples in all R&M houses  had lead loadings in excess of clearance levels.

6.     A reviewer commented that information on the temporal relationship of blood lead collection
to dust sampling would be helpful in interpreting the study findings.  A section was added to the
report explaining that the question of the temporal relationship of blood lead data to environmental
lead data is relevant only for study houses that  were occupied at the time of the intervention. The
initial blood lead  concentrations of the children  moving into the vacant houses after  R&M
intervention would not reflect an equilibrium with their new environment.  In occupied houses, the
vast majority  (72  to 93 percent by group) of the corresponding initial campaign  blood and
environmental samples were collected within three weeks of each other and, in nearly all cases, within
35 days  of each other.  The text also  includes information  on the  time periods in which the
environmental  samples were collected by group.

       It  should be noted that EPA has established  a public record  for peer  review  under
Administrative Record 159. The record is available in the TSCA Nonconfidential Information Center

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located in Room NE-B607, Northeast Mall, 401 M Street, SW, Washington, D.C.  The Center is
open from 12:00 noon to 4:00 pm, Monday through Friday, except for legal holidays.

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2.0  CONCLUSIONS

       The enrollment and data collection goals of the initial campaign were attained, and the data
are in compliance with laboratory performance objectives (see section 3.0). Therefore, the initial data
collection campaign has produced valid baseline measurements for the longitudinal study of R&M
interventions.

       Houses that were candidates for R&M intervention were identified through the collaboration
of private property owners and a housing organization. Additional field and laboratory efforts were
required to attain the final study frame of 75 R&M houses. Twenty-seven R&M candidate houses
were sampled and later excluded  mainly due to the failure of owners to submit applications to the
Maryland Department of Housing and Community Development for R&M loan funds, family moves,
and concerns for the safety of field staff. Comparison of the excluded R&M-candidate houses to the
75 R&M houses showed no evidence of selection bias based on environmental lead concentrations,
lead loadings, dust loadings, or the blood lead concentrations of resident children. Because of the
apparent unwillingness of owners, as opposed to landlords,  to apply for a state loan to do R&M
work, the excluded group had  a higher proportion of owner-occupants (19 percent) than did the
R&M group (4  percent).

       The three R&M groups  under investigation were found to be comparable  at the pre-
intervention baseline. No patterns of statistically significant differences were found between R&M
groups  on environmental variables,  children's  blood lead  concentrations, reported monthly
rent/mortgage amounts, and ages of study children. However, R&M Level I houses tended to have
the lowest baseline lead concentrations, lead loadings and dust loadings of the three R&M groups.
R&M Level IQ houses  tended to  have  the highest measurements, and R&M Level n  houses
registered intermediate measurements.  This pattern may be due, in part, to the fact that at the time
of sampling, all  of the R&M Level I houses were occupied by study families,  all of the R&M Level
HI houses were vacant, and the R&M Level n houses were a mix of occupied and vacant houses.
Dust lead has been reported by  others to accumulate  in vacant houses.25

2.1    Environmental Lead

       An examination of house dust data by surface type showed that within each study group
window wells tended to have the highest dust lead concentrations and lead loadings; window sills and
entryways had intermediate levels; and floor and upholstery items had the lowest levels.  With regard
to dust  loadings, window wells and air ducts had the highest measurements across study groups,
followed by interior entryways. These surfaces would be expected to be among those where dust
accumulates in houses. In order to  study houses in terms of overall dust lead levels and dust loadings,
summary measures were calculated based on weighted averages of all sample types within a house.

      Based on the overall weighted average measures of dust lead in a house, differences in lead
concentrations  of approximately one order of magnitude were found between modern urban and
previously abated houses and between previously abated and R&M houses. Order of magnitude
differences were also found between modern urban and previously abated houses in terms of overall
lead  loadings. Overall lead loadings in the R&M groups, however, were one to almost two orders

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of magnitude higher than those in previously abated houses and between two and three orders of
magnitude higher than in the modern urban houses.  The findings based on overall dust loadings had
a similar ordering by group, but the relative differences between groups were much less pronounced.
These patterns indicate that the higher dust lead loadings in R&M houses, relative to modern urban
and previously abated houses, were due to higher dust lead concentrations in the R&M houses, and
particularly in vacant units  and on certain surface types  (e.g., window sills and wells),  to a
combination of higher lead concentrations and higher dust loadings.

       Modern houses built after 1979 and located in clusters of urban housing were included in this
study as a comparison group of houses that presumably contained little or no lead-based paint. Since
1978, the U.S. Consumer Product Safety Commission has limited the lead content of residential
paints to only trace amounts for regulatory purposes (i.e., to 0.06 percent by weight in the dried
film26). This type of modern housing (located in clusters of similar housing as opposed to scattered
site units built after 1979) is generally expected to reflect the lowest residential and ambient lead
levels in the urban environment.  This study did not include the collection of street dust or playground
dust, which would be useful in comparing ambient lead levels. Lead concentrations measured in drip-
line soil and exterior entryways, however, provided  some evidence that the modern urban group did
differ from the other four study groups in terms of ambient lead levels.  In modern urban houses, lead
concentrations in soil (geometric mean=63 ug/g; maxinium=154 ng/g) and exterior entryway dust
(geometric mean=137 ug/g; maximum=764 ug/g) were very low. In the other four groups, geometric
mean dust lead concentrations in exterior entryway samples ranged from 2,200 to 7,000 ng/g, and
the limited number of soil lead  measurements ranged from 230 to 16,000 ng/g.  The low soil lead
concentrations in the modern urban group might  be due to the use of replacement sod and soil
around these houses at the time of construction, or at some other time in the past.

       Like R&M houses, the previously abated houses are scattered-site properties located in older
neighborhoods where, based on the age of the housing, houses are likely to contain lead-based paint.
As mentioned above, these houses showed a pattern of intermediate dust lead concentrations and
lead loadings relative to modern urban and R&M houses. The initial campaign data represent a point
in time two to four years after the houses were abated using comprehensive methods. Notably, the
study found that the geometric mean lead loadings for  interior floors and window sills, but not
window wells, remained below Maryland's interim clearance standards (200, 500, and 800 ng/ft2 for
interior floors, window sills and window wells, respectively) and the geometric floor levels were close
to HUD's revised interim clearance standard for floors (100 ^g/ft2) (Table  16). (Note that lead
loadings in this report are based on the use of the R&M cyclone, not wipe samples.) On average,
most (58 percent) of the relevant dust samples per house in the previously abated houses had loadings
below Maryland's interim clearance standards, although the range per house was wide (14 percent
to 86 percent). These findings add to the scant information in the literature regarding the long-term
effectiveness of comprehensive lead paint abatement in older housing.
2.2    Correlations Between Environmental Variables

       The amount of lead in dust on various household surfaces was found to be moderately to
highly correlated, whereas the amount of dust per unit area on the various surfaces was generally less

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well correlated. Dust lead on interior household surfaces was correlated with window well lead,
exterior entryway lead, and exterior soil lead. These patterns of correlations suggest that there is
some mixing of lead across surface types within houses and between interior and exterior sources and
that an overall measure of dust lead exposure for houses should be investigated further.  The
directions of movement of lead and the sources of lead in dust cannot be determined, however, from
an analysis of  these cross-sectional data. An assessment of sources of lead in dust on various
household surfaces would require additional work, such as analyses of stable lead isotope ratios of
paint,  soil, and dust.  Toward this end, a pilot study is underway of stable lead isotopes using
environmental samples from a small number of R&M houses.

2.3    Blood Lead

       The geometric mean blood lead concentration in children living in the modern urban housing
group, 4.8 jig/dL, falls between the national geometric mean of 3.6 ug/dL for U.S. children of the
same age range (12 to 60 months) and the geometric mean for U.S. African American children in this
age range, 5.6 ug/dL.27 All children in the modern urban houses had blood lead concentrations equal
to or less than the CDC level of concern of 10 ug/dL. The geometric mean blood lead concentrations
in children in the other study groups ranged from 9.9 to 14.2 ug/dL and were higher than the national
geometric mean of 9.7 ng/dL estimated for U.S. African American children aged 12 to 60 months
from low-income families  living in central cities with populations more than one million.27 The
maximum baseline blood lead concentration in this study was 42 ug/dL in a  child in the R&M Level
III group, the group with the highest baseline geometric mean blood lead level. Generally,  higher
blood lead concentrations were anticipated in  this group because City Homes, Inc., a major source
of R&M houses, has a policy of accepting families with lead-poisoned children as tenants in its
improved properties.

       When study groups were combined, blood lead concentrations and environmental lead levels
were found to be correlated, with statistically significant correlation coefficients ranging from r=.36
to .64. Blood lead concentration was correlated with  lead loadings and/or lead concentrations of
every environmental sample type, except for air duct dust and water. Air ducts may not be accessible
to children, and water was not found to be an important source of exposure due to low lead
concentrations. The absence of statistically significant correlations between blood lead concentration
and environmental lead levels within study groups is due to differences among groups, the smaller
numbers of children per group, and the narrower  ranges of environmental lead levels within groups,
particularly in the modern urban houses.

-------
3.0 QUALITY ASSURANCE

3.1    System Audit

       Laboratory and field activities have been subjected to regular review to assure conformance
with procedures prescribed in the QAPP.2  This ongoing audit has focused on the  sampling and
analytical procedures used, their documentation, the training of field and laboratory personnel, and
the adequacy of related facilities and equipment. Reports were prepared annually.  Inadequacies were
noted in these reports and subsequently corrected. Only minor problems, not directly related to data
quality, were noted during the initial sampling campaign.

3.2    Data Audit

       To verify the accuracy of the data used in this report, the quality control officer conducted
a  stratified random audit of 10 percent of the field and laboratory data generated during the initial
sampling campaign. Prior to the audit, laboratory and data staff had completed three independent 100
percent checks of the data.  The audit procedure involved the verification of information in the final
data base against the original field and laboratory data.  Samples to be audited were selected by
computer using random number sequences.  Sampling was stratified to ensure that samples were
randomly selected to represent every analytical batch.  Probably as a result of the  extensive quality
control effort prior to the audit by the quality control officer, the audit did not identify any errors.
3.3    Performance Audit

       In order to assure that the sampling and analytical protocols employed in the R&M study yield
data of sufficient quality, a number of different types of quality control samples were included in the
study design. These samples were designed to control and assess data quality in each phase of the
data collection and analysis process which was potentially subject to random and/or systematic error.
Blank samples,  including field blanks and method blanks, were  included to assess  procedural
contamination by lead.  Recovery samples, including standard reference materials, spiked samples,
and calibration verification samples, were included to indicate the accuracy of analyses while duplicate
samples indicated precision of analyses.  Standard control charts were generated quarterly showing
percent recovery of a standard reference material, percent recovery of spiked samples, spike/spike
duplicate precision, initial calibration values, continuing calibration values,  percent recovery  of
continuing calibration values, drift of continuing calibration values within a run, field blanks, and
method blanks. Separate control charts were generated for each combination of sample matrix and
analytical instrument used.  Of the almost 3,900 quality control samples included in these analyses,
the control limit was never exceeded for any quality control parameter.

       In addition to these internal quality control efforts, the KKRI Trace Metals Laboratory has
participated in external quality control programs for environmental lead samples and blood lead
concentrations as a part of the R&M study.  Beginning in September 1993, the laboratory has
participated in the Environmental Lead  Proficiency Analytical Testing (ELPAT) program for
environmental samples.  This program is  administered through EPA's National Lead Laboratory

                                             8

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Accreditation Program which recognizes laboratories capable of performing routine analysis of lead
in paint chips, dust,  and or soil samples with prescribed accuracy.  The KKRI Trace Metals
Laboratory has been rated as "proficient" for the evaluation of lead in paint chips, soil, and dust wipes
every  quarter  since  1993.   The  KKRI  Trace  Metals Laboratory  also  participates in the
HRSA/Wisconsin Blood Lead Proficiency Testing Program. Three blind blood samples are analyzed
every month as a part of this program. The KKRI laboratory has achieved a 100% accuracy rating
for GFAA analysis of blood lead since beginning this analysis in 1993.

Statistical Analyses of OC Data

       Because of the overlapping nature of the sampling campaigns in this longitudinal study,
samples from several campaigns are generated and analyzed concurrently.  Consequently, there  is no
unique set of quality control data that can be attributed to the initial sampling campaign. As a result,
the quality control data reported here represent all data submitted as a part of quarterly reports
through October 18,1995. These data include all of the samples from the initial sampling campaign
plus varying numbers of samples from subsequent campaigns.

       Statistical analyses of the quality control samples are included as Tables I through HI. With
the exception of soil samples, the percent recovery of standard reference material and the percent
recovery of spike and spike duplicates all fell within a tolerance interval of 70 to 130  percent.
Precision was very high, generally less than a 1 percent difference between spike and spike duplicate
samples. Percent recovery of initial and continuing calibration samples fell within a tolerance interval
of 90 to 110 percent. Drift was limited to an average of less than 2 percent over a run.  On average,
field and method blanks showed extraneous lead contamination of the samples to be trivial.  No
systematic evidence of contamination was observed.

-------
Table I:     Descriptive Statistics And Tolerance Limits For Percent Recovery For SRM
            And Spiked Samples And Percent Differences  Between Spiked And Spike
            Duplicate Samples
sSปWjpfet^|>e


Standard
Reference
Material







dpilce/apiKe
Duplicate





ir^ot&ttatysfe

ICP-DV*
GFAA-DV
GFAA-Sb
GFAA-W*
ICP-DV
SPIKE
ICP-DV
SPIKE DUPLICATE
ICP-DV
PERCENT DIFFERENCE
GFAA-DV
SPIKE
GFAA-DV
SPIKE DUPLICATE
GFAA-DV
PERCENT DIFFERENCE
GFAA-S
SPIKE
GFAA-S
SPIKE DUPLICATE
GFAA-S
PERCENT DIFFERENCE
GFAA-W
SPIKE
GFAA-W
SPIKE DUPLICATE
GFAA-W
PERCENT DIFFERENCE
Fawfeerof
' &no])ie& i
••:
111
204
9
44
276
276
276
205
205
205
10
10
10
45
45
45
Miabmmi
<%> I
78.01
80.93
81.48
80.45
84.67
83.91
-20.99
81.50
79.00
-20.33
84.00
48.00
-3.31
72.80
74.40
-7.41
ItfaxilWHB*
TO
153.64
119.59
108.39
129.18
119.92
121.03
13.29
118.00
125.00
19.12
125.00
115.10
13.19
117.80
120.60
13.51
^ffttfbetrfe
Sfeaป
: c%>
97.17
94.55
96.03
102.19
97.56
97.36
0.20
100.11
100.11
0.04
103.36
95.77
1.53
96.45
96.48
-0.06
SfcMMfaN
Error

0.6<
0.4(
2.9<
1.55
0.2<
0.3(
0.1J
0.41
0.50
0.34
4.57
6.02
1.63
1.48
1.58
0.52
   DV = cyclone dust
   S = soil
   W= water
                                       10

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Table II:    Descriptive Statistics And Tolerance Limits For Percent Recovery For ICV And
            CCV
SawpteTyiMs
ICV
CCV
l^ttf^afflftin
,•
ICP-DV8
GFAA-DV
GFAA-Sb
GFAA-Wc
ICP-DV
% TRUE VALUE
ICP-DV
% DRIFT
GFAA-DV
% TRUE VALUE
GFAA-DV
% DRIFT
GFAA-S
% TRUE VALUE
GFAA-S
% DRIFT
GFAA-W
% TRUE VALUE
GFAA-W
% DRIFT
ISfatnhero*
Sawpfes
177
64
21
42
1072
1072
231
231
47
47
117
117
matowm
<%> i
94.30
93.50
97.50
96.00
90.04
-13.95
91.00
-12.04
89.00
-11.44
90.50
-12.80
$fa*Uw}8>
<%}
109.98 .
109.00
107.50
108.50
109.94
14.53
1 12.50
11.39
109.00
5.83
110.00
11.68
<&m&nfe
Metot -
m \
101.29
102.69
102.60
103.24
99.24
-2.25
102.13
-0.70
100.70
-1.36
102.14
-1.03
Standard
!ft*r
X
0.24
0.44
0.54
0.52
0.12
0.14
0.27
0.30
0.71
0.58
0.40
0.40
  DV = cyclone dust
  S = soil
  W= water
                                        11

-------
Table 1H:    Descriptive Statistics For Field Blanks And Method Blanks
Samjtel'yjje
Field Blank
Method Blank
: T$$e;
18.40
0.26
1.59
12.64
3.37
0.44
S^Bdar3Ei-rar
s "*•"%•• '
5.56
0.09
0.24
3.80
1.76
0.10
   Field blanks are analyzed by ICP or GFAA
                                          12

-------
 4.0 STUDY DESIGN AND SAMPLE COLLECTION PROCEDURES

    The R&M study targeted houses in low-income neighborhoods where children are at highest risk
of  lead-poisoning due to exposure in dust and in deteriorating paint. It is important to emphasize
that the R&M study was not designed as an intervention study in the homes of lead-poisoned children
per se, although some study children did have blood lead elevations at baseline.  Instead, the study
started by identifying eligible intervention and control houses with eligible children. The eligibility
criteria for children were based on age and other criteria, but not blood lead concentration (see
section 4.4).   The sections below provide an overview of the study design followed by descriptions
of the R&M interventions, recruitment and enrollment procedures, selection criteria for houses and
children,  selected characteristics of the study houses, and sample collection procedures.

4.1           Overview Of Study Design

    The R&M study has two main components and five groups of study houses. The first component
is designed to obtain serial measurements of lead in venous blood of children between the ages of six
and 60 months at enrollment, as well as house dust, exterior soil, and drinking water in three groups
of 25 houses (a total of 75 houses), each receiving one of three levels of R&M intervention. The
second component is designed to collect a comparable set of measurements in two groups of control
houses. Table 1 summarizes the types of data planned for collection by study group and by campaign
(i.e., pre-intervention, immediate post-intervention, two months, six months, 12 months, 18 months,
and 24 months post-intervention). Blood lead and dust lead measurements are planned in all R&M
study houses at each campaign, except for blood lead at the immediate post-intervention campaign.
Measurements  of lead in exterior soil were taken at baseline and are planned at immediate post-
intervention, and at six and 18 months post-intervention.  Measurements of lead in drinking water
were made at baseline in occupied R&M houses, and are planned at immediate post-intervention in
previously vacant R&M houses, and at six and 18 months post-intervention. The study questionnaire,
designed  to obtain information on demographics and covariates that could influence lead exposure
in the home (e.g., hobbies and child behavior), will be administered at six month intervals starting at
enrollment.

    R&M intervention houses (vacant and occupied) were identified in collaboration with owners and
operators of low-income rental properties as explained in section 4.3. Occupied houses which were
eligible for R&M intervention were randomly assigned to receive either R&M Level I (low level
intervention) or R&M Level n (intermediate level intervention). Vacant houses which were eligible
for R&M intervention were randomly assigned to receive either R&M Level H or R&M Level ffl
(high level intervention).  The R&M Level n intervention was designed to be performed in both
occupied  and vacant houses, and the randomization scheme was designed to ensure that  equal
numbers of houses (n=25) were assigned to each R&M intervention level. In order to allow for a
better estimation of the post-intervention rate of re-accumulation of lead in dust and for periodic
assessments of the need for further cleanups/repairs during the follow-up period, more  frequent
sampling campaigns are planned in all the R&M groups during the first year of follow-up (Table 1).
                                           13

-------

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-------
    The need for additional cleanups/repairs during the entire follow-up period will be determined by
a  comparison of the follow-up dust lead  loadings and blood lead concentrations with their
corresponding pre-intervention levels.  Further cleanups/repairs will be performed whenever dust
lead loadings at most interior sites in a house re-accumulate to levels that exceed pre-intervention
levels. This assessment will exclude interior sites with low baseline dust lead loadings (e.g., <100
ug/ft2) that remain low at follow-up despite small increases in their lead loadings. In contrast, clean-
up/repair will be considered  for sites with high levels at baseline and at follow-up (e.g., >25,000
ug/ft2) where the follow-up level approaches, but does not exceed, the corresponding baseline value.

    The second component of the study is to obtain serial measurements of lead in venous blood of
children six through 60 months of age at enrollment, and in house dust, soil, and drinking water in
two groups of control houses.  The first control group consists of 16 houses drawn from a group of
houses that received comprehensive lead-paint  abatement in demonstration projects in Baltimore
between May 1988 and February 1991.3'4  The second control group consists of 16 modern urban
houses built  after 1979 and presumably free of lead-based paint.  The types and frequency of
measurement are the same in the two control groups (Table 1).  Measurements of lead in blood and
settled dust were conducted at enrollment and are planned at six months, 12 months, 18 months,
and 24 months post-enrollment.  Measurements of lead in exterior soil and drinking water were
conducted at  enrollment  and  are planned at six months and 18 months post-enrollment. The study
questionnaire will be administered at six month intervals starting at enrollment. The two years of
follow-up in the previously abated control group will provide an opportunity to measure the efficacy
of comprehensive abatement four to six years after abatement. Pre-abatement and immediate post-
abatement data on dust lead loadings were collected in these  houses as part of the previously
mentioned demonstration project and are available for use in the R&M study.

    It should be noted that the sample sizes of the control groups were reduced from 25 to 16 houses
each due to reductions in the scope and funding of the project.  The number of control houses, rather
than the number of R&M houses, was reduced  because the  former (and in particular the modern
urban houses) were expected to have less inter-house variability with respect to both blood lead and
dust lead. This was borne out in the study findings. Furthermore, two types of houses were originally
planned for inclusion in the modern urban control group:  houses in clusters of urban houses built
after 1979, and houses in scattered sites, which had been extensively rehabilitated after 1979.  When
the sample size of modem urban houses was reduced to 16 houses, only the former were included
as the negative (no lead paint) control group (see section 4.5 for additional descriptive information).
It was expected that this type of cluster housing would reflect the lowest residential and ambient lead
levels in the urban environment.

4.2           Repair & Maintenance Interventions

    The R&M interventions were financed by the Maryland Department of Housing and Community
Development (DHCD) through a special loan program open to low-income owner-occupants and
private property owners who rent their properties to low-income tenants.  To meet DHCD loan
eligibility requirements and the pre-requisites for R&M-type interventions imposed by the study, the
three levels of R&M interventions were planned for study in  lead-painted houses that had no

                                           15

-------
structural defects and that were maintained according to the eligibility criteria listed in section 4.4.
 The R&M intervention costs were capped by DHCD as follows: R&M Level I, $1,650; R&M Level
E, $3,500; and R&M Level HI, $6,000 to $7,000. The latter range is due to program criteria and
pre-existing program agreements. The three levels of intervention, described in detail in the QAPP,2
are described briefly below.

   R&M Level I includes the following elements: wet scraping of peeling and flaking lead-based
paint  on interior surfaces; limited repainting of scraped surfaces; wet cleaning with a tri-sodium
phosphate detergent (TSP) and vacuuming with a high efficiency paniculate air (HEPA) vacuum to
the extent possible in an  occupied house; the provision of an entryway mat; the  provision of
information  to occupants and owners; and stabilization of exterior surfaces to the extent possible
given the budget cap.  Two key additional elements in the R&M Level n interventions are floor
treatments to make them smooth and more easily cleanable and in-place window and door treatments
to reduce abrasion of lead painted surfaces. In addition to all of this, R&M Level m intervention
includes window replacement and encapsulation of exterior window trim with aluminum coil stock
as the primary window treatment, the encapsulation of exterior door trim with aluminum, and more
durable floor and stairway treatments. All R&M households receive cleaning kits for their own wet
cleaning efforts. The kits include a bucket, sponge mop, sponges, a replacement sponge mop head,
a TSP cleaning agent, and the EPA brochure entitled "Lead Poisoning and Your Children."

4.3           Recruitment And Enrollment

   R&M study houses were identified from lists of addresses provided by owners of private rental
properties in  low-income neighborhoods of Baltimore and by City Homes, Inc., a non-profit housing
organization, which owns and  operates low-income rental properties to demonstrate methods for
managing and maintaining such properties. The small number of owner-occupant properties in the
R&M intervention groups (n=4) were identified through the Kennedy Krieger Research Institute's
Lead  Poisoning Prevention Program and outside sources.  The  previously abated houses were
identified from lists  of houses abated in past years as part of lead paint abatement demonstration
projects conducted by  the City of Baltimore and the Kennedy Krieger Research Institute.  The
modem urban houses built after 1979 were identified by house-to-house visits conducted in multiple
clusters of such housing in Baltimore.

   The enrollment process was done in two stages: pre-enrollment and formal enrollment. These
activities were undertaken by study field workers who conducted extensive home visits (1,100 visits
to more than 650 modern urban, previously abated, and candidate R&M houses) during the spring
and summer of 1992. More than 90 percent of households identified as potentially eligible for the
study indicated an interest in participating.  This pre-enrollment activity yielded 100 interested and
eligible households for formal enrollment. Formal enrollment refers to the obtaining of signed
informed consent statements for study participation from parents or legal guardians for both
environmental and biological sampling.  Separate consent statements were obtained for each child
enrolled in the study using forms approved by the Joint Committee on Clinical Investigation of the
Johns Hopkins Medical Institutions.
                                           16

-------
   Between the time of formal enrollment and the commencement of the initial data collection
campaign in January 1993, some enrolled households became ineligible, primarily due to the aging
of the children and the moving of families to other dwellings.  In some cases, the losses re-initiated
pre-enrollment activity to identify an additional pool of potential  study participants. The initial
environmental sampling campaign in the modern urban and previously abated control houses was
performed between January and July 1993. The baseline environmental sampling in R&M houses was
conducted between March 1993 and November 1994.

4.4           Selection Criteria For Houses And Children

   Houses and children were selected for participation in the study based on a rigid set of criteria.
The  first set of selection criteria listed below was applied to all five study groups.  Additional
selection criteria were applied to the three R&M groups and to the previously abated control group.

Selection criteria applied to all five study groups:

•  House size was approximately 800 to 1,200 ft2.

•  The house was  structurally sound without pre-existing conditions that could impede or
   adversely afFect the R&M treatments and the safety of the workers and field staff (e.g., roof
   leaks or unsafe floor structures).  This criterion eliminated substandard housing in need of
   major renovation and, therefore,  not suitable for R&M-type interventions and included
   housing that was somewhat maintained and suitable for the interventions under investigation.
   This criterion also allowed a house to  qualify for the special state loans that were to finance
   the study interventions.

•  Utilities (heat, electric; and water) were available to facilitate interventions and field sampling.

•  The household included at least one child six through 60 months of age at enrollment who
   was not mentally retarded or physically handicapped with restricted movement and for whom
   the house was a primary residence (i.e., child was reported to spend at least 75 percent of
   time at the address). Also, the child's family has no definite and immediate plans to move.

•  The house was not excessively furnished.  This criterion allowed dust collection in all houses,
   as well as the intervention and cleanup efforts in occupied R&M houses.

Additional selection criteria applied to R&M houses:

•  The house contained lead-based paint (defined in Maryland as ^0.7 mg Pb/cm2 or ^0.5
   percent lead by weight as determined by wet chemical analysis) on at least one surface in a
   rninimum of two rooms or, in the absence of testing, was constructed prior to 1941 (when
   lead-based paints were commonly used14).
                                           17

-------
 •  Interior house dust lead loadings prior to intervention exceeded Maryland's interim post-
    abatement clearance levels (i.e., 200 ng/ft2 for floors, 500 ng/ft2 for window sills, and 800
    fig/ft2 for window wells) at a minimum of three locations.18> *

 •  The house had  12 or fewer windows  needing R&M  work.  This is to allow for the
    implementation of the R&M interventions, given limited resources.

 Additional  selection criterion applied to previously abated houses:

 •  At least  two pairs of  pre-abatement  and immediate post-abatement  dust-wipe lead
    measurements from the same floor, window sill, and window well surfaces were available
    from previously collected  data.  This ensured that data were available to the R&M study on
    pre- and post-abatement baseline dust lead levels in these control houses.
4.5           Characteristics Of Study Houses

    The R&M houses and the previously abated houses are all scattered-site houses located in older
residential neighborhoods in Baltimore. All houses were built prior to 1941. More than 98 percent
of the R&M houses and 100 percent of previously abated houses were rowhouses, which constitute
the predominant type of housing in inner-city Baltimore neighborhoods. As mentioned previously,
the 16 modern urban houses are rowhouses located in clusters of urban houses built after 1979.  The
clusters of modem urban houses, which served as the sampling frames for this study, were all located
in, or are adjacent to, urban housing neighborhoods constructed prior to 1941.  Each cluster had
multiple rows of housing built after 1979 and the rows generally extended the length of a city block.
The characteristics of the  study houses were typical of housing in low-income neighborhoods in
Baltimore. Unfortunately, data do not exist to allow a comparison of dust lead levels in study homes
.to those in city homes in general.

    Study houses were  generally similar in terms of housing characteristics that might influence
patterns of dust movement into and within a house (i.e.,  overall size and number of windows, house
type and design, condition, degree of setback from the street, and the presence of porches and yards).
The selection criteria ensured that the study houses would be similar in terms of size, number of
windows, and, to some degree, overall condition. With regard to type and design, all five groups of
study houses consisted primarily of two-story rowhouses (not located at the end of the row) with
two or three rooms on  each level.  Floor plans were produced  for each study house in order to
facilitate the sample collection activities.  The Appendix displays the floor plans of two typical study
rowhouses (R&M #436, and modern urban #212).
       a   In 1990, these clearance levels were adopted as interim post-abatement clearance
 levels by the U.S. Department of Housing and Urban Development (HUD).19  In 1995, HUD
 revised its interim clearance standard for floors to be 100 jug/ft2.20
                                           18

-------
    Most study houses lacked porches (84 percent), were not located on narrow alleys (77 percent),
and were minimally set-back from the street (77 percent).  Houses with minimal set-back were those
with no front yards and entryways leading directly from the sidewalk, or from stairs ascending directly
from the sidewalk. The other 23 percent of study houses were more than minimally set-back from
the street, primarily due to the presence of porches or small front yards.  Only four houses (3 percent)
were classified as being set-back from the street by more than a modest amount as described above.
Unlike the other four groups of houses, most of the modern

Table 2:      Selected Characteristics Of Houses By Study Group
&aftyr&w&
-. s *% ••
R&MLevell
R&M Level H
R&M Level ffl
Previously Abated
Modern Urban
Sซ*JJAva3lafote!or
Sampling
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20
22
4
19
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17
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56 32 12
78 17 4
96 4 0
81 19 0
69 31 0
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30
30
31
13
urban control houses had yards in the front or back of the house. For this reason, exterior soil was
available for collection from 69 percent of the modern urban houses as opposed to only 15 percent
of the R&M houses and 19 percent of the previously abated houses.

    Table 2 compares selected housing characteristics across the five study groups.  R&M Level I
houses were most likely to have a porch (32 percent) and to be more than minimally set-back from
the  street (44 percent).  R&M Level I (12 percent) and modern urban houses (13 percent) were least
likely to be located on narrow alleys. As shown in Table 3, the proportion of carpet samples in
composites was on average very low - essentially zero - in R&M Level I, R&M Level n, R&M Level
III, and previously abated houses.  On average, the proportion of carpets making up floor dust
composites in modern urban houses was very high, averaging close to 100 percent.  In all groups,
differences were noted in the distribution of carpets between first and second stories.  The influence
of these factors will be explored hi future analysis of longitudinal trends in dust lead levels.
4.6
Sample Collection Procedures
   Venous blood was collected from study children at the Kennedy Krieger Institute's Lead
Poisoning Clinic by a pediatric phlebotomist into 3 mL Vacutainersฎ with EDTA added as an
anticoagulant.  Information on the study children and their households was collected using a
                                           19

-------
structured interview questionnaire. Trained field teams administered the questionnaires and collected
all environmental samples, including field quality control (QC) samples.

    Settled house dust was collected using a modified high-volume cyclone sampler originally
developed for EPA for the evaluation of pesticide residues in house dust. The modified device,
referred to as the R&M cyclone, is described hi detail and characterized elsewhere.15'16 The device
consists of a Teflon*-coated cast aluminum cyclone attached to hand-held Dirt Devilฎ vacuum as the
air  mover for the system. A 100 mL Teflon* microwave digestion liner was used as the sample
collection container to eliminate a sample transfer step in the laboratory, thereby reducing the risk of
sample loss.

    The sampling plan for settled dust included the collection of three composite dust samples from
the floors in each house at each campaign:  one composite in rooms with windows on the first story,
one composite in rooms with windows on the second story, and one composite in first and second
story rooms without windows.  Each composite was composed of samples collected from two
randomly selected 1 ft2 (929 cm2) perimeter floor locations in each appropriate room. If a randomly
selected location were carpeted or covered with an area rug, this information was recorded on the
sample collection form and the carpet or rug was sampled using the R&M cyclone.  Settled dust was
also collected in two composite window sill samples and two composite window well samples in each
house at each sampling campaign.  Samples were composited by story from all windows available for
sampling. Examples of windows not available for sampling were those with window air conditioners
and those blocked by furniture.  Settled dust was also collected as individual (i.e., not composite)
samples from horizontal portions of air ducts, interior and exterior entryways, and the main items of
upholstered furnishing in each dwelling.

    Three individual soil core samples were collected from the top 0.5 inch (1.3 cm) of soil
from three randomly selected locations at the drip-line and then combined as one composite sample.
Each soil core was collected into a polystyrene liner using a six-inch (15.2 cm) stainless steel recovery
probe.

    Drinking water samples were collected as two-hour fixed-time stagnation samples  from the
kitchen faucet. This procedure involved running the cold water for at least two minutes to flush the
pipes and, after a two-hour interval, collecting the first flush of water in a 500mL polyethylene bottle.
A list of field sample types is provided in Table 4.

    Families were informed by letter of the results of all dust lead and blood lead tests. Results of
dust tests were provided on a qualitative basis with recommendations for housekeeping priorities to
address areas with high lead levels. Families in houses in which water and  soil lead concentrations
exceeded EPA guidance levels were provided with additional recommendations for avoiding lead
exposure.  Additionally, letters were sent to the parents/guardians of the study children with the
results of the blood lead tests to be shared with the child's primary care provider. All blood lead test
results were reported to the Maryland Blood Lead Registry as required by Maryland law. The effect
of the provision of information to families will be considered in the interpretation of the study findings
in subsequent reports.

                                            20

-------
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Table 4:     Types Of Field Samples
Sample Type '< * |
Perimeter Floor Composite Settled
Dust
Window Sill Composite Settled
Dust
Window Well Composite Settled
Dust
Air Duct/Upholstery Settled Dust
Interior Entryway Settled Dust
Exterior Entryway Settled Dust
Soil Core
Drinking Water
Field QC
,; * ; \%: Sampling Locations/Specifics -' -
First story and second story rooms with windows; rooms
without windows
First and second story
First and second story
Upholstery was sampled if air ducts were unavailable
Not directly on entryway mat
Not directly on entryway mat
Drip-line composite
Kitchen faucet
Blanks and duplicates for all field sample types
                                       22

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5.0 LABORATORY ANALYSIS PROCEDURES

   Interior and exterior settled dust, exterior soil, water and venous blood samples were analyzed
at the Kennedy Krieger Research Institute's Trace Metal Laboratory using established analytical
methods.  Closed vessel microwave digestion was used for dust, soil, and water samples according
to modified SW 846 Methods 3015 and 3051.  Analysis of dust digestates was performed using
Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP) according to  SW 846 Method
6010 and/or Graphite Furnace Atomic Absorption Spectrometry (GFAA) according to SW 846
Method 7421.  Soil and drinking water were analyzed by GFAA according to SW 846 Method 7421.
Venous blood was analyzed by GFAA and ASV.21 Table 5 summarizes these procedures.
Table 5:      Summary Of Laboratory Procedures
Sample Type
Dust
Soil
Drinking Water
Blood
Fr^FrepAralldii
Drying and
gravimetrics
Drying, sieving and
homogenization
Acidified
Stabilized in EDTA
after collection
PreparatilHi -
Microwave digestion
using 1:1 HNO,:H7O
Microwave digestion
using l:lHNO,:HjO
Microwave digestion
using 1:1HNO,:H2O
Addition of matrix
modifier/Triton X-100
solution
Analysis
ICP/GFAA2
GFAA
GFAA
GFAA/ASV"
  Samples with lead concentrations below the limit of quantitation of the ICP instrument were
  analyzed by GFAA.

  ASV was used in addition to GFAA for rapid reporting of blood lead
                                         23

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6.0 DATA PROCESSING AND STATISTICAL ANALYSIS PROCEDURES

6.1          Data Processing

   Data analyzed as a part of this study were derived from the field collection forms, the laboratory
instruments, and the questionnaires. Raw data of all types were transferred to the data manager who
uploaded the data to a VAXStation 3100 computer for later analysis.  A summary of the data
processing steps employed for the three sources of data is presented below.

•  The field data consist of all data recorded on the field collection forms for settled dust, soil, and
   drinking water samples, as well as room and window inventory data. Data were double entered
   for verification from the field forms into ASCII data files by a commercial data entry firm. These
   raw data files were transferred to the data management team for management, storage, and later
   analysis.  Field data forms were checked  for completeness  and accuracy by the  outreach
   coordinator and data manager prior to data entry. Data were verified again by laboratory staff
   from final SAS* file printouts.

•  Laboratory data were electronically stored by each laboratory instrument.  Gravimetric data (tared
   and loaded weights for dust and soil samples) were generated and stored by the Mettler Balance.
   Lead concentration measurements for dust samples were made and recorded by the ICP. Lead
   content in drinking water, soil, and blood, as well as dust samples with low lead concentrations
   were made by GFAA.  Electronically stored  laboratory data from the Mettler, ICP, and GFAA
   instruments were imported to Paradox* (v.4.0) by laboratory staff for tracking of samples.
   Paradoxฎ data were then converted to ASCII files by the Data Management Team for uploading
   to the VAXStation.  A SASฎ program read in the laboratory data for environmental and blood
   samples and created SAS* data sets for data analysis. The data were verified again by laboratory
   staff from final SASฎ file printouts.

•  Questionnaire data forms were double entered for verification by a data entry firm into ASCII
   data files. These raw data files were verified in-house and transferred to the data manager.  A
   SAS* program read in the raw data and created SASฎ data sets for data analysis.
6.2          Data Summary

   The study frame consisted of 107 houses occupied by 140 study children in the five groups (Table
6). It should be noted that the final total was 107 houses because an additional house was included
in each control group (15 planned; 16 enrolled) due to concerns that some families might
be moving soon after enrollment. Furthermore, two of the 25 houses originally assigned to the R&M
Level n intervention group were  reclassified as R&M Level HI houses because of additional
renovations at the time of the intervention.  In both cases, the landlord independently undertook
renovations beyond the scope defined by the R&M Level n criteria.  Thus, this report is based on 25
R&M Level I houses, 23 R&M Level n houses, 27 R&M Level HI houses, 16 modern urban houses,
and 16 previously abated houses. The number of study children per household ranged from one to

                                          24

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four. An additional 27 R&M candidate houses and 23 resident children were tested and subsequently
excluded from further study for reasons listed in Table 7.  The questionnaire was administered in
every home at the time of enrollment. In vacant homes, the questionnaire was administered when the
family moved in.  As part of the initial campaign, a total of 129 questionnaires were collected.  A total
of 1,370 environmental samples of 10 types (excluding field QC samples) and 163 blood samples
were collected from these 134 houses.  Table 8 provides information on the types and numbers of
samples planned, collected, and analyzed for lead content in the 107 study houses and 27 excluded
houses. Table 9 provides a summary of the numbers and types of samples by study group.

    In the 107 study houses, 166 of the planned samples could not be collected because the sampling
sites were inaccessible or nonexistent. Two of the 1,533 obtainable samples from potential study
homes were missed and one other sample was not collected for no documented reason (Table 8). All
environmental and blood samples collected in the initial data collection campaign were analyzed for
lead content. Thus, this data collection effort met the data quality objective of having ^95 percent
(/.e., 99.8 percent) of obtainable samples actually being collected, chemically analyzed, and available
for data analysis. Section 7.0 reports on compliance with pre-established laboratory performance
criteria.
6.3           Statistical Analysis Procedures

    The purpose of this report is to summarize cross-sectional data using descriptive statistics.  For
data analysis purposes, lead measures less than the instrument detection limit (IDL) were calculated
as the IDL divided by the square root of two ( n=17).22 For lead values less than the limit of
quantification (LOQ) but greater than the IDL, the observed value was used in the data analysis
(n=76).

    Descriptive statistics were produced using SASฎ software.23 The Shapiro-Wilk test for normality
indicated that the environmental and blood lead measurements were not normally distributed. As
expected, use of the natural logarithm (In) transformation reduced the amount of skewness; therefore,
all exploratory data analyses were done on the transformed data.  A further complication of the data
set are the repeated measures from a house, which violate the assumption of independence invoked
for most analyses.  To overcome this problem, a mixed- effects model was used to account for the
correlation of samples within a house.  These calculations resulted in a better estimate of the mean
and confidence interval for the settled dust from floors in rooms with windows, window sills, window
wells, and children's blood. These calculations were done by study group and surface type.
                                           25

-------
Table 6:     Numbers Of Houses And Children By Study Group
: % ^ - \; Study Graซ|> , ^
R&MLevell
R&M Level H
R&M Level m
Previously Abated using Comprehensive
Methods
Modern Urban - built after- 1979
TOTAL IN FINAL STUDY FRAME
***,
1 Rouses
' 25
23*
27a
16b
16b
107
-," *te.7;::*'
Cfeil
-------
Table 7:  Reasons For Exclusion Of Candidate R&M Houses
"V "• •.'
'/"'; /, Bea&M*forlx^ปfcป
Non-cooperative landlord/owner-occupant; re: application for
R&M loan funds
Family moved (including 3 evictions)
Concerns for safety of outreach staff (includes 3 houses that
had R&M work)
Vacant house was vandalized
Owner received lead abatement notice
Tenant was suing landlord
Outreach staff unable to contact family
Family did not meet state loan program's income eligibility
criterion for tenants
Family refused further participation
House was not child's primary residence
Landlord made house ineligible by replacing windows in a
house assigned to R&M Level I intervention
TOTAL
> • Jfct "
Houses
7
5
7
1
1
1
1
1
1
1
1
27
                                       27

-------
Table 8:        Types And Numbers Of Samples Collected And Analyzed For Lead
                  (Excluding QC Samples) As A Part Of The Initial Campaign
SaffljdfcTyjift
Perimeter Floor Dust
Composite in Rooms
with Windows
Perimeter Floor Dust
Composite in Rooms
without Windows
Window Sill Dust
Composite
Window Well Dust
Composite
Interior Entryway
Dust
Exterior Entryway
Dust
Air Duct Dust
Upholstery Dust
TOTAL DUST
Soil Core - drip line
Drinking Water
Venous Blood
GRAND TOTAL
$i*bire$
s~S|ปfr
Hous*
2a
1
2a
2a
1
1
lb
-
10
1
I1
I/child
^13
CbBeCted -
-", ~iaiปt
--&aa$
UoUtSeS "
217
58
212
203
107
104
29
60
990
25
73
1401
1228
"• •• v
,?„„ ' .;
ฃ&&te*fe
* *yt', '•-"
EwhKted
Bouses
54
13
54
53
27
27
10
16
254
7
21
23
305
f d-YrJ
.' C*>8ซcted 1
••••aw*" ,'\
Afealjafcd
fat-jta*til ;
271
71
266
256
134
131
39
76
1244
32
94
163J
1533
.• !>•
' -."" rt :
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House* "
0
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83
82h
0
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1661
         One composite sample was obtained per story.
         Upholstery sample was collected if air duct sample could not be obtained
         49 bouses did not have rooms without windows.
         Sills on one story were inaccessible in 1 MU and 1 PA house.
         Wells on one story were inaccessible in 3 MU, 1 PA, 6 R&M I, and 1 R&Mn house.
         Wet surfaces in 1 MU and 1 PA.
         Air duct & upholstery were inaccessible/not present in 1 PA, 1 R&M 1,6 R&M II, 8 R&M m, and 2 were missed (1 of which had no reason
         recorded as to why the sample was not collected).
         80 houses had no drip-line soil; in 2 houses soil was inaccessible due to snow and ice.
         Driricing water is not part of the initial campaign sampling plan for vacant R&M houses; these samples will be collected at the post-intervention
         campaign.
         Includes 3 specimens (2 venous, 1 capillary) collected by primary provider and analyzed by outside laboratory.
         1 family refused for one child.
         164 of these 166 (99%) were not collected because the sampling sites were nonexistent or inaccessible.
                                                         28

-------
Table 9:      Types And Numbers Of Samples Collected By Study Group (Excluding
             QC Samples) As A Part Of The Initial Campaign
, Sawipk TyJ* ' " ';
s
Perimeter Floor Dust
Composite in Rooms
with Windows
Perimeter Floor Dust
Composite in rooms
without windows
Window Sill Dust
Composite
Window Well Dust
Composite
Interior Entryway
Dust
Exterior Entryway
Dust
Air Duct Dust
Upholstery Dust
TOTAL DUST
Soil Core - drip line
Drinking Water
Venous Blood
GRAND TOTAL
ColJectซl
teHS
Modern
Ikfean
fitous**
33
4
31
30
16
15
0
16
145
11
16
19
191
Collected
in 16
PrtVfeUSlV
Abated
Senses
32
g
31
31
16
15
1
14
148
3
16
23
190
Collected
In 25
R&MLe^il
ESiattt**
52a
19
50
43
25
25
1
23
238
5
25
33
301
Cdfecfed
in 23
R&MUvel
ii HoWs ••
46
14
46
45
23
23
12
7
216
5
14
32
267
{fe&Efed
"in.*?,
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lBt'&Btt&ฃ^
54
13
54
54
27
26
15
0
243
1
2
33
279
      Includes two samples collected in basements used as living spaces.
                                        29

-------
       In the correlation analyses, a single dust measure was required to represent each surface
within a house, whereas two measures had been collected. Therefore, a weighted average measure
was calculated as follows: for lead loadings the sum of the lead in the samples was divided by the sum
of the areas of the sampling locations; for lead concentrations the sum of the lead across samples was
divided by the sum of the sample weights; for dust loadings the sum of the sample weights was
divided by the sum of the areas of the sampling locations.  Similar calculations were made for the
overall summary measures of dust lead concentrations, lead loadings, and dust loadings for houses
based on the weighted averages of all dust sample types in a house.

       The comparison of R&M study houses to excluded R&M-candidate houses was based on t-
tests for normally distributed data and Chi-Square and Fisher's Exact Tests for binomially distributed
data. Since the two groups were comparable, combined data from study houses and excluded houses
were used to calculate  the correlations among  the various environmental variables  and the
correlations between blood lead and environmental lead variables.  Only those children living in an
occupied houses for at least two months prior to the initial campaign were included in the correlations
of environmental variables with blood lead. Children who moved into  the vacant R&M houses after
intervention were excluded from the analysis since their blood lead concentrations would not reflect
an equilibrium with their new environment. The correlation analysis was done twice, first using the
youngest child in the house to  avoid the problem of non-independence, and then using all eligible
children per household. Future reports will take into account the clustering (non-independence) of
children in the analysis of the blood lead changes.
                                            30

-------
7.0 RESULTS

       The findings are presented below in  the following order:  demographics of the study
population; blood lead concentrations; and dust, soil and water lead concentrations and lead and dust
loadings.  These sections are followed by results of  the comparison of R&M houses to excluded
R&M candidate houses and the analysis of correlations between environmental variables and between
blood lead and environmental lead. Regarding the latter, it is important to bear in mind the temporal
relationship of blood collection to environmental sampling, detailed below.

       By design, all of the R&M Level IE houses and half of the R&M Level n houses were vacant
when the baseline environmental samples were collected. The initial blood lead measurements for the
study children in the vacant houses were made close to the time of occupancy, which occurred, in all
cases, after the completion of the R&M work. For this reason, the initial blood lead concentrations
of these children would not reflect an  equilibrium with their new environment. Thus, the question
of the temporal relationship of blood lead concentrations to environmental lead levels is relevant only
to houses that were occupied at the time of the intervention (i.e., R&M Level I, some R&M Level
n, and all control houses). In these relevant groups, the vast majority (72 to 93 percent by group)
of the corresponding initial campaign blood and environmental samples across groups were collected
within three weeks of each other and, in nearly all cases, within 35 days of each other (Figure 1).

7.1    Demographics

       The study was conducted in Baltimore households with reported low-to-moderate monthly
rents and mortgages.  All study participants were African-American.  The overall mean reported
monthly rent or mortgage payment was $324 (range $107 to $580, 10 missing values).  Eighty
percent of all households reported that they were renters, and 20 percent reported that they were
owner-occupants.  Household sizes ranged from two to 10 persons.  Seventy-two percent of
households had one child enrolled in the study. The remaining households had multiple children
enrolled as follows:  two study children in 24 percent of the households; three study children in 2
percent of the households; and four study children in 2 percent of the households.

       Table 10 provides descriptive statistics by study group for the following variables: reported
ownership, reported monthly housing payment (rent/mortgage amount),  reported household size,
number of study children per house, and ages  of study children.  The major differences between
groups were in ownership status and monthly housing payments. These differences stem from
differences between modern urban households and the four other study groups.  Nearly all (94
percent) of the  modern urban households are homeowners with higher reported monthly housing
payments than the occupants of R&M and previously abated houses who  are, for the most part,
tenants (95 percent and 88 percent, respectively).
                                           31

-------
Figure 1:     Temporal Relationship Of Blood Collection To Environmental Sampling



    Tim* Between Initial Dust Collection And  Initial Blood Collection for R & M Occupied Mous*
         100%
       5   80%

       u
           20%
                                                               ™  "'
                  1-7    B-1*   10-21   22-2B   2B-30   38-ซ2


                                           Number of Dayป
                                                                      oSBE   i oซ*>,    , eeW
                                                                     SO-Sa   87-03  O4-7O
   Note:  One Blood collection we* 12S  deym  prior to the oorramponaino duet eollectlor
    Time Between Inltlel Ouปt Collection And  Initial Blood Collection For Modern Urben House*
        u


       ฐ-
           ao%
           20%
            0%
                                                  16-21          22-28


                                           Nlumbor of Days
                                                                               2B-3B
      Time Between initlel Duปt Collection And Initial Blood Collection For Previously Abated Houses
           80%
           60%
—   4O%
           2O%
             0%
       ฃ
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        a
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                                     8-1*          18-21          22-2O


                                            Number of Days
                                                                               23-36
  * Note: One blood collectron was 1 9O days after the dust collection and Is not displayed Mara.



                                                 32

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7.2    Blood Lead

       Geometric mean blood lead concentrations in study children were 9.9 ug/dL in R&M Level
I houses, 13.8 ug/dL in R&M Level n houses, 14.2 ng/dL in R&M Level m houses, 12.8 ug/dL in
previously abated houses, and 4.8 ug/dL in modern urban houses (Table 11). The geometric mean
blood lead concentration was statistically significantly lower in the modern urban group as compared
to each of the other four groups. Differences between the geometric mean blood lead concentrations
in the three R&M groups were not statistically significant.  The ranges of blood lead concentrations
by group were 2 to 22 ug/dL in R&M Level I,  4 to 36 ug/dL in R&M Level n, 2 to 42 ng/dL in
R&M Level ffl, 4 to 28  ug/dL in previously abated, and 2 to 10 ng/dL in modern urban. Figure 2
displays box plots of children's blood lead concentrations by study group.

7.3    Environmental Lead

The environmental data are presented by study group in the following three formats:

•      Tables with descriptive statistics (n, minimum, maximum, geometric mean, standard deviation
       on the log scale,  and 95 percent confidence interval for the geometric mean).

•      Side-by-side bar  graphs displaying geometric mean values.

•      Side-by-side box plots displaying the distributions of log-transformed variables.
       For comparison across study groups within surface types, side-by-side box plots are displayed
for each surface type by study group (Figures 6 to 8).  For comparisons across sample types within
each study group,  side-by-side box plots are displayed for each surface type by study group (Figures
9 to 11).  In a box plot display, 50 percent of the data are contained in the box; the bottom of the box
is the 25th percentile value and the top of the box is the 75th percentile value.  The horizontal line
inside the box represents the sample median. The vertical lines extending from the box show the
range of data that falls within one-and-a-half inter-quartile ranges of the box. Extreme values are
indicated by an asterisk.24  The width of a box in any given side-by-side box plot is proportional to
the number of observations.

7.3.1    Settled Dust

       Tables 12 through 14 display descriptive statistics for baseline dust lead concentrations, dust
lead loadings, and dust loadings, for the five study groups and eight surface types. The geometric
mean concentrations and their 95 percent confidence intervals for floors in rooms with windows,
window sills, and window wells are calculated by an analysis that takes clustering (non-independence
of samples) into account (see section 4.3).
                                            34

-------
Figure 2:    Blood Lead Concentrations By Study Group At Initial Campaign
loglO(PbB)
1.0
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                                   35

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The figures are grouped as follows:

•      Figures 3 to 5 are bar graphs showing the geometric mean dust and soil lead concentrations,
       dust lead loadings, and dust loadings, respectively, for the five groups and eight surface types.

•      Figures 6 to 8 are side-by-side box plots of distributions of log-transformed (log,0) lead
       concentrations, lead loadings and dust loadings, respectively for each surface type by study
       group. These figures are for comparison across groups.

•      Figures 9 to 11 display side-by-side box plots of distributions of log-transformed (Iog10) lead
       concentrations, lead loadings, and dust loadings for each study group by surface type. These
       figures are for comparison of sample types within each study group.

       For dust lead loadings and lead concentrations, the measurements tended to be lowest in
modern urban houses, intermediate in previously abated houses, and highest in the R&M houses
(Figures 3, 4, 6, and 7).  Across R&M groups, R&M Level I  houses tended to have the lowest
baseline lead measurements, R&M Level n houses had intermediate measurements, and R&M Level
m houses had the highest measurements. The differences in geometric mean values across R&M
Levels I to HI generally were not found to be statistically different (Tables 12 and 13).  In the case
of dust loadings, the measurements across all groups tended to be more uniform, but were still higher
in R&M groups, particularly on window  sills and window wells (Figure 5).  Pre-intervention dust
samples from relevant sites indicated that 75  percent of the samples from R&M Level I homes, 85
percent of the samples from R&M Level n homes, and 98 percent of the samples from R&M Level
IE homes had lead loadings in excess of Maryland's interim clearance levels for floors, window sills,
and window wells. Forty-two percent of the relevant samples in previously abated houses and 14
percent of the relevant samples in modern urban houses exceeded these guidelines (see section 4.4).

       Across all surface types, geometric mean lead loadings and concentrations were substantially
lower in modern urban houses than in the other four study groups (Tables 12 and 13). For all sample
types with sufficient data for comparison, dust lead concentrations in modern urban houses were
statistically significantly lower than those in the previously abated houses and than those in the three
R&M levels (Table 12). Previously abated houses had significantly lower lead concentrations and
lead loadings than R&M Level I to m houses for window sills and window wells (Tables 12 and 13).
For all sample types with sufficient data for comparisons, dust  lead loadings in the modern urban
group were statistically significantly lower than those in the three R&M groups.
                                           36

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-------
       Geometric mean dust lead concentrations for all surface types in modem urban houses were
<338 ug/g.  In previously abated houses, geometric mean dust lead concentrations across all surface
types were <2,252 ug/g.  For each  of the three R&M groups, geometric mean dust lead
concentrations for all surface types were greater than the corresponding geometric mean values for
the modern urban and previously abated houses. Maximum observed dust lead concentrations by
study group were as follows:  1,978 ug/g in modem urban houses (floor); 76,710 ug/g in previously
abated houses (window sill); 296,951 ug/g in R&M Level I houses (window sill);  365,310 in R&M
Level n houses (window well);  and  817,029 ug/g in R&M Level HI houses (window well) (Table
12).

       In the modern urban houses, geometric mean lead loadings for all surface types were below
60  ug/ft2, except for window  wells (geometric mean=347 ug/ft2).  In previously abated houses,
geometric mean dust lead loadings for all surface types were ^470 pg/ft2, except for window wells
(geometric mean=l,816 ug/ft2). For all three R&M groups, baseline geometric mean  dust lead
loadings for all surface types were greater than the corresponding geometric mean values for modern
urban and previously abated houses. Maximum dust lead loadings in all  groups were  found  on
window wells (6,400 ug/ft2 in modern urban houses, 37,988 ug/ft2 in previously abated houses,
3,360,469 ug/ft2 in R&M Level I houses, 2,183,020 ug/ft2 in R&M Level H houses, and 12,250,842
ug/ft2 in R&M Level m houses) (Table 13).

       Geometric mean dust loadings by group were < 1,000 mg/ft2 for all groups and surface types,
except for  air ducts,  and window wells in R&M Level I to El houses (range of geometric
means=7,051 to 13,916 mg/ft2), interior entryways and window sills in R&M Level ffl houses
(geometric means=l,556 mg/ft2 and  1,012 mg/ft ,  respectively), and window wells in modern urban
houses (geometric mean=l,021 mg/ft2) (Table 14).

       An examination of house dust data by surface type indicated a somewhat similar ordering of
geometric mean lead levels across groups for both lead concentrations and  lead loadings as shown
in Table 15. Dust loadings tended to be highest for window wells, window sills, and air ducts and
lowest for upholstery and floors in rooms without windows (Figure 5).

7.3.2  Overall Summary Measures Of Dust Lead And Dust Loading

       To  compare differences in overall dust  measurements across  study groups, descriptive
statistics were developed for weighted average measurements calculated for each house across all
eight surface types (see section 4.3). Descriptive statistics based on these overall lead loadings, lead
concentrations, and dust loadings are presented by  study group hi Table 16. Figure 12 is a bar graph
of geometric means for each of the three overall measures by study group.

       For  overall geometric  mean dust lead concentrations, approximate order of magnitude
differences were found between  groups:  modern urban (235 ug/g), previously abated (2,420 ug/g),
R&M Level I houses (19,044 ug/g), R&M Level II houses (14,414 ug/g),  and R&M Level m
                                          49

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-------
houses (17,548 ug/g). Thus, overall dust lead concentrations were nearly two orders of magnitude
higher in the R&M houses than in the modern urban houses. For dust lead loadings, order of
magnitude differences were again found between modem urban (83 ug/ft2) and previously abated (908
Hg/ft2) houses. Overall lead loadings in R&M Levels, however, were one to almost two orders of
magnitude  higher than those in previously abated houses, and between two and three orders of
magnitude higher than in the modern urban houses.

       Differences in overall dust loadings across groups were less pronounced. Overall geometric
mean dust loadings were similar in modern urban (351 mg/ft2) and previously abated (375 mg/ft2)
houses and lower than those found in R&M houses (870 to 2,706 mg/ft2). Higher dust loadings in
R&M II and R&M Level HI houses may be due in part to the fact that most of these houses were
vacant at the time of the initial environmental sampling campaign.

7.3.3  Drip-Line Soil

       Only 25 of the 107 (23 percent) study houses had drip-line soil (five R&M Level I houses, five
R&M Level II houses, one R&M Level IE house, three previously abated houses, and 11 modern
urban houses).  Descriptive statistics on soil lead concentrations are displayed in Table 17.  In modern
urban houses, the soil lead concentrations ranged from 29 ug/g to 154 jig/g.  In all other groups, the
soil lead concentrations ranged from 233 ug/g to 15,968 ug/g.  Figure  13 shows side-by-side box
plots of soil lead concentrations by group.

7.3.4  Drinking Water

        Collection of drinking water in the initial campaign was limited to occupied houses to allow
time for any plumbing repairs that might be made by the owners of the vacant R&M houses at the time
of intervention.  Included in the descriptive statistics in Table 18 are three water samples collected
in vacant houses (two R&M Level HI houses and one R&M Level n house) before the decision was
made to limit the initial water sampling to occupied houses. The water lead concentrations ranged
from less than the instrumental limit of detection (<0.6 ug/L) to 44 ug/L.  Overall, 50 percent of the
water samples had lead concentrations less than the limit of quantification (LOQ, generally <3 ug/L).
The geometric mean concentration of lead in water for the modern urban, previously abated, and
R&M Level I  and n houses was <3 ug/L. Figure  14 displays side-by-side box plots of water lead
concentrations by study group.

7.4    Comparison of Study Houses And Excluded Houses

        There were 27 excluded houses in which environmental data were collected but the houses
were not selected for study; all were candidate houses for R&M interventions.  These excluded
houses were compared to the final group of 75 R&M houses to assess the possible selection bias.
Both groups were a mix of occupied and vacant units at the time of sampling. No statistically
significant  differences were found between these two groups based on geometric mean dust  lead
concentrations, lead loadings, or dust loadings for the eight surface types (Tables 19 to 21).
                                           53

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Table 19:
Comparison Of Mean Dust Lead Concentrations In The 75 R&M
Houses To The 27 Excluded R&M Candidate Houses
' SaaJpfeType \>
Air Duct
Exterior Entryway
Floors in Rooms with Windows
Interior Entryway
Window Sill
Upholstery
Window Well
Floors in Rooms without
Windows
Blood
laM*aปI*a *
7.36
(28)
8.31
(74)
7.99
(75)
8.25
(75)
9.69
(75)
6.55
(30)
10.10
(74)
7.17
(45)
2.48
(98)
fo.Mซ*aI*ad
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: Eroded Houses
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6.86
(10)
8.39
(27)
7.98
(27)
8.32
(27)
10.13
(27)
6.91
(16)
10.33
(27)
7.61
(13)
2.50
(23)
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-1.25
0.26
-0.04
0.26
1.85
1.24
1.18
1.19
0.15
;l^>b>|t|
f'-
0.22
0.80
0.97
0.80
0.07
0.22
0.24
0.24
0.88
                                     57

-------
Table 20:
Comparison Of Mean Dust Lead Loadings In The 75 R&M Houses To
The 27 Excluded R&M Candidate Houses
-- -" S?o*iปte1Vฃ*
Air Duct
Exterior Enttyway
Floors in Rooms with Windows
Interior Entryway
Window Sill
Upholstery
Window Well
Floors in Rooms without
Windows
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11.04
(28)
6.93
(74)
7.02
(75)
7.66
(75)
9.26
(75)
4.19
(30)
12.50
(74)
5.85
(45)
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-------
Table 21:
Comparison Of Mean Dust Loadings In The 75 R&M Houses To The 27
Excluded R&M Candidate Houses

•- k$ant|Hฃ *yya? •
Air Duct
Exterior Entryway
Floors in Rooms with Windows
Interior Entry
Window Sill
Upholstery
Window Well
Floors in Rooms without
Windows
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(28)
5.53
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5.94
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6.33
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9.30
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5.87
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5.59
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6.02
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6.17
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4.76
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9.48
(27)
5.41
(13)
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0.50
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0.16
0.42
0.22
0.59
0.23
0.67
                                     59

-------
Furthermore, there was no statistically significant difference between the genders or the blood lead
concentrations  of children living in study homes and  excluded homes.   When  the monthly
rental/mortgage payment was analyzed by R&M group, no significant differences were found between
the excluded houses and the corresponding R&M houses. Because of the apparent unwillingness of
owners, as opposed to landlords, to apply for a state loan to do R&M work, the excluded group had
a higher proportion of owner-occupants (19 percent) than did the R&M group (4 percent).
7.5    Correlations Among Environmental Lead Variables

       Tables 22 to 24 display the correlation matrices by sample type for lead concentrations, lead
loadings, and dust loadings. Data from the 27 excluded houses were included in these analyses since
no significant differences were found between R&M houses and the excluded houses.

       For lead concentrations, the correlations between the various environmental sample types
(exterior dust, interior dust on seven different surfaces, and drip-line soil) were statistically significant
and in the range of r=.41 to .80, except for water and air ducts. Water lead concentration was not
significantly correlated with any of the other environmental lead concentrations, and air duct dust lead
concentration was correlated only with floor and interior entryway dust lead concentration. The
highest correlation coefficient (r=.80) was found between lead concentrations on window wells and
window sills.  The next highest correlation coefficient (r=.77) was between dust collected in exterior
entryways and drip-line soil. Figure 15 is a scatterplot matrix of lead concentration data showing the
scatterplots for each possible pair of environmental sample types.

       For lead loadings, the correlations among the dust sample types were statistically significant
and in the range of r=.29 to .82, except for air ducts, which were significantly correlated with only
the dust lead loadings found in interior entryways (r=.37).  The highest correlation coefficient (r=.82)
was between the lead loadings found on window wells and window sills. The next highest correlation
coefficient for lead loadings (r=.72) was for floors in rooms with windows and window sills.

       The correlations between dust loadings of the various surface types are weaker, and fewer
are statistically significant, as compared to lead concentrations and lead loadings.  The statistically
significant correlations range from r=.25 to .55.  Upholstery and air duct dust loadings were not
correlated with any other surface types. Exterior entryways were correlated only with window sills.
The highest correlation coefficient for dust loading measurements of (r=.55) is between floors in
rooms with and without windows, followed by a correlation coefficient of r=.46 between window
sills and floors in rooms with windows.
                                           60

-------
     Figure 15:   Scatterplot Matrix Between Environmental Lead Concentrations
         1   3   5
                             2   4
        2.0    3.5
          12345
 Floor
            Sill
                    Well
                            Exterior
                                      Interior
                                                                                    -0.5  1 0
                                               Airduct
                                                          Uph.
                                                                   FNW
                                                                             Soil
                                                                                     Water
234
                  2345
2345
2.0    3.5
                                                                          1.5  3.0
     FNW = Floors in rooms without windows
                                              61

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7.6    Correlations Between Blood Lead And Environmental Lead

       Children who had lived in a study house for at least two months prior to the initial blood lead
measurement were included in the analysis of the correlation between blood lead and environmental
lead (see section 6.3). Information on the temporal relationship of blood lead to environmental data
is provided in section 7.0.

       Correlations between blood lead concentrations and environmental lead variables were not
found to be statistically significant when examined separately within each of the relevant groups of
houses occupied  at the  time of the initial campaign.  (See Table 11 for the range of blood lead
concentrations by study group.)  The analysis was then performed using combined data from all the
relevant study houses, plus data from the 19 excluded houses, with paired blood and environmental
data.  The range of blood lead concentrations for the combined data set was 0.9 to 65.5  //g/dL.
Figure 16 displays scatterplot matrices for blood lead concentration versus dust lead concentration
and lead loading for floors, window sills, and window wells.

       Table 25 displays the correlations between blood lead concentration of the youngest child in
each household and lead  loading, lead concentration, and dust loading by surface. The correlations
between blood lead and environmental lead concentrations were all statistically significant and in the
range of r=.36 to .64, except for air ducts and drinking water.  The highest correlation coefficient
found was r=.64 for upholstery followed by r=.56 for interior entryways, r=0.52 for floors in rooms
with windows, and r=.49 for window sills.  The correlations between blood lead and dust lead
loadings were also statistically significant, except for air ducts and drinking water, but the correlations
tended to be weaker than those for lead concentrations.  The significant correlation coefficients
ranged from r=.35 to .50.  The highest coefficient was r=.50 for blood lead and lead loadings on
upholstery, followed by r=.49 for blood lead and lead loadings on floors in rooms with windows.  The
only statistically significant correlations between blood lead and dust loadings were those between
blood lead and upholstery (r=.24) and blood lead and window wells (r=.34).  When all study children
were considered in the analysis (Table 26), the correlations tended to be weaker than those obtained
using the youngest child in each household.
                                            65

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8.0 REFERENCES

1.    Lanphear,  BP, Weitzman M, Tanner M, et al.   1994.   The Relationship of Lead-
      Contaminated House Dust and Blood Lead Levels Among Urban Children.  Final Report to
      the National Center for Lead Safe Housing.

2.    Quality Assurance Project Plan for the Kennedy Krieger Institute Lead Paint Abatement and
      Repair and Maintenance Study in Baltimore.  1992.  Subcontract No. 41950(2348)-2207;
      EPA Contract No. 68-DO-0126, Office of Pollution Prevention and Toxics, Design and
      Development Branch, Washington DC.

3.    Farfel  MR, Chisolm JJ and Rohde CA. 1994. The longer-term effectiveness of residential
      lead paint abatement.  Environmental Research 66:217-221.

4.    Farfel MR and Chisolm JJ. 1991.  An evaluation of experimental practices for abatement of
      residential lead-based paint: report on a pilot project.  Environmental Research 55:199-212.

5.    U.S. Agency for Toxic Substances and Disease Registry (ATSDR). 1988. The Nature and
      Extent of Lead Poisoning in the United States: A Report to Congress. USDF1HS Public
      Health Service, Atlanta, Georgia.

6.    U.S. Centers for Disease Control. Preventing Lead Poisoning in Children. Statement by the
      Centers for Disease Control. USDHHS PHS, Atlanta, Georgia.

7.    Chisolm JJ, Mellits ED, Quaskey SA. 1986.  The relationship between the level of lead
      absorption in children and the age, type, and condition of housing. Environmental Research
      38:31-45.

8.    Clark  CS, Bornschein RL, Grote J,  et al.  1991.  Urban lead exposures of children in
      Cincinnati, Ohio. Journal of'ChemicalSpeciation andBioavailability 3:163-171.

9.    Charney E, Kessler B,  Farfel, M, Jackson D.  1983.  A controlled trial of the effect of dust-
      control measures on blood lead levels. New England Journal of Medicine 309:1089-1093.

10.   Bornschein RL, Succop PA, Krafft KM, Clark CS, Peace B and Hammond PB.  1986.
      Exterior surface dust  lead,  interior house dust  lead and childhood exposure in an urban
      environment.   In:  Trace Substances in Environmental Health XX,  ed. D.D. Hemphill,
      University of Missouri, Columbia, Missouri, 1986.
                                          69

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11.     Charney E. 1982. Lead poisoning in children: the case against household lead dust. In: Lead
       Absorption in Children: Management,  Clinical and Environmental Aspects.   Eds.  JJ
       Chisolm, Jr and DM O'Hara. Urban and Schwarzenberg, Baltimore and Munich, pp.79-88.

12.     Roels HA, Buchet J-P, Lauwerys RR, et al.  1980.  Exposure to lead by the oral and
       pulmonary routes of children living in the vicinity of a primary lead smelter. Environmental
       Research 22:81-94.

13.     Sayre JW, Charney E, Vostal J. and Pless IB.  1974. House and hand dust as a potential
       source of childhood lead exposure. American Journal of Disabled Children 127:167-170.

14.     U.S. Department of Housing and Urban Development. 1990. Comprehensive and-workable
      plan for the abatement of lead-based paint in privately owned housing: Report to Congress.
       HUD, Washington DC.

15.     Farfel MR, Bannon D, Lees PSJ, Lim BS and Rohde CA.  1994. Comparison of two
       cyclone-based collection devices  for the evaluation of lead-containing residential dusts.
       Applied Occupational and Environmental Hygiene 9:212-217.

16.     Farfel MR, Lees PSJ, Rohde CA, Lim BS and Bannon D.  1994. Comparison of wipe and
       cyclone methods for the determination of lead in residential dusts.  Applied Occupational &
       Environmental Hygiene 9:1006-1012.

17.     Farfel MR, Bannon D, Chisolm JJJr, Lees PSJ, Lim BS and Rohde CA. 1994. Comparison
       of a wipe and a vacuum collection method for the determination of lead in residential dusts.
       Environmental Research 65:291-301.

18.     Annotated Code of Maryland. 1988. Procedures for abating lead containing substances from
       buildings.   COMAR26.02.07, Title  26,  Maryland  Department  of  the  Environment
       Regulations, Effective Date: August 8, 1988.

19.     U.S. Department of Housing and Urban Development, Office of Public and Indian Housing.
       1990. Lead-Based Paint: Interim Guidelines for Hazard Identification and Abatement in
       Public and Indian Housing. Washington DC.

20.     U. S. Department of Housing and Urban Development. 1995. Guidelines for the Evaluation
       and Control of Lead-Based Paint Hazards in Housing. Washington DC.

21.     Bannon DI, Murashchik C, Zapf CR, Farfel MR and Chisolm, JJ Jr.   1994.  A graphite
       furnace AAS method of blood lead measurement using matrix matched standards. Clinical
       Chemistry 40:1730-1734.
                                          70

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22.    Homung, RW and Reed, LD 1990. Estimation of average concentration in the presence of
       nondetectable values. Applied Occupational and Environmental Hygiene 5:46-51.

23.    SAS Institute Inc.  1990. SAS* Language: Reference, Version 6, First Edition.  Cary, NC.

24.    Tukey, JW. 1977. Exploratory Data Analysis. Addison-Wesley, Reading, Massachusetts.

25.    Sayre JW and Katzel MD. 1979. Household  surface lead dust: its accumulation in vacant
       homes. Environmental Health Perspectives 29:179-182.

26.    U.S.  Consumer Product  Safety Commission.  1977.   Lead-containing paint and certain
       consumer  products bearing lead containing  paint (16 CFR 1303).  Federal Register
       42:44192-44202.

27.    Brody DJ, Pirkle JL, Kramer RA, et al.  1994. Blood lead levels in the US population: phase
       1 of the third national health and nutrition examination survey (NHANES IE, 1988 to 1991).
       JAMA 272:277-283.
                                          71

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APPENDIX: Floor Plans of Two Typical Study Rowhouses
                       72

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50272-101
        REPORT DOCUMENT
                PAGE
 1. Report No.
 EPA747-R-95-012
                                                                                    3. Recipient's Accession No.
 4. Title and Subtitle
    Lead-Based Paint Abatement and Repair and Maintenance Study in Baltimore:
   Pre-Intervention Report
                                             5. Report Date
                                                August 1996
                                                                                    6.
 7. Authors)
    Farfel, M.R.; Rohde, C.; Lees, P.S.J.; Rooney, B.; Bannon, D.I.; Derbyshire, W.
                                             8. Performing Organization Rept No.
 9. Performing Organization Name and Address
    Kennedy Krieger Research Institute
    707 N. Broadway
    Baltimore, MD 21205
                                             10. Project/Task/Work Unit No.
                                             11. Contract ฉor Grant (G) No.
                                             Contract # 68-D4-0001
 12. Sponsoring Organization Name and Address
    U.S. Environmental Protection Agency
    Office of Pollution, Pesticide and Toxic Substances
    Washington, DC 20460
                                             13. Type of Report & Period Covered
                                             Final Report; 1993
                                             14.
 IS. Supplementary Notes
    The following people were major contributors to the study: Dr. Julian Chisolm, Kennedy Krieger Research
    Institute; Vance Morris, MD Department of Housing and Community Development; Ron Menton and
    Bruce Buxton, Battelle Memorial Institute; and PauJ Constant and Gary Dewalt of Midwest Research Institute.
 16. Abstract (Limit: 200 words)
    This report presents the results of the initial data collection of the Lead-Based Abatement and Repair and
    Maintenance (R&M) Study in Baltimore, MD.  The R&M study is designed to characterize and compare the
    short (2-6 months) and long-term (12-24 months) efficacy of comprehensive lead abatement with less costly
    and potentially more effective R&M interventions.  The R&M interventions are designed to reduce children's
    exposure to lead in residential paint and dust. The study targets low-income housing where children are at
    high risk. This report provides pre-intervention baseline data for the longitudinal study of changes in levels of
    lead in children's blood and in settled house dust associated with three levels of R&M intervention. The
    results showed that children's blood lead concentrations were significantly correlated with lead levels in house
    dust from entryway and six types of interior surfaces.
 17. Document Analysis
  a Descriptors.'
    Kennedy Krieger Research Institute, lead, lead clinic, lead dust testing, blood lead testing, lead-based paint,
    lead-dust loading, lead-dust concentration, dust loading, low cost interventions, repair and maintenance,
    children's blood lead, lead exposure reduction in children, lead hazard reduction, blood lead-dust lead
   correlation.
  b. Identifiers/Open-Ended Terms:
   Lead poisoning, lead abatement, inductively coupled plasma emission spectroscopy (ICP-AES), flame atomic
   absorption spectroscopy (FAAS), graphite furnace atomic absorption spectroscopy (GFAAS), cyclone-based
   dust collector, Baltimore Repair and Maintenance dust collector (BRM).

  c. COSATI Field/Group:
 18. Availability Statement
19. Security Class (This Report)
            Unclassified
                                       20. Security Class (This Page)
                                                   Unclassified
21. No. of Pages
       85
 (SeeANSI-239.18)
                                               OPTIONAL FORM 272 (4-77)
                                                      (Formerly NTIS-35)

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