United States
Environmental Protection
Agency
Office of
Toxic Substances
Washington DC 20460
EPA-560/5-87-001A
December, 1986
Toxic Substances
&EPA
Pentachlorophenol in
Log Homes:
A Study of Environmental
and Clinical Aspects
Executive Summary
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DISCLAIMER
This document has been reviewed and approved for publication by the
Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S.
Environmental Production Agency. The use of trade names or commercial products
does not constitute Agency endorsement or recommendation for use.
-------
PENTACHLOROPHENOL IN LOG HOMES: A STUDY OF
ENVIRONMENTAL AND CLINICAL ASPECTS
EXECUTIVE SUMMARY
By
John M. Hosenfeld
EPA Prime Contract Nos. 68-02-3938 and 68-02-4252
MRI Project Nos. 8201-A(11) and 8801-AC02)
December 11, 1986
Prepared for
U.S. Environmental Protection Agency
Office of Pesticides and Toxic Substances
Field Studies Branch, TS-798
401 M Street, S.W.
Washington, DC 20460
Attn: Sandra Strassman-Sundy
Work Assignment Manager
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PREFACE
This executive summary provides an overview of the results ob-
tained on Midwest Research Institute Project No. 8201-A, Work Assignment
No. 11, "Development of Field Survey and Analysis Stratagies" for the Envi-
ronmental Protection Agency (EPA Prime Contract Nos. 68-02-3938 and 68-02-
4252). This work was a joint venture between MRI and the Center for Occu-
pational and Environmental Health (COEH) of Johns Hopkins University as a
subcontractor (COEH Subcontract No. 117-7900-17 and 130-7900-9). Under the
direction of Mr. John M. Hosenfeld, MRI was responsible for the overall task
management, the environmental sampling (assisted by Ms. Marilyn J. Gabriel),
and laboratory analyses of environmental and biological samples for penta-
chlorophenol (performed by Ms. Leslie Moody).
COEH, under the direction of Dr. Edward A. Emmett, was responsible
for recruitment and project coordination (performed by Ms. Robin M. Friesem),
assistance in environmental sampling (Dr. Peter S.J. Lees, Mr. Patrick Breysee),
collection of biological samples and physical examinations (Drs. Rebecca Bascom
and Diane Bennett), statistical analysis of environmental, clinical, biochem-
ical data (Ms. Joan L. Jefferys) and data interpretation in conjunction with
MRI. The clinical laboratory tests were performed by Pathologists Service
Professional Associates, Atlanta, GA, and Montefiore Medical Center, Bronx, NY.
This summary report was prepared by Mr. Hosenfeld.
The author wishes to thank the EPA task manager, Sandra Strassman-
Sundy, for providing the appropriate guidance, background, and assistance in
shepherding this project to completion.
MIDWEST RESEARCH INSTITUTE
John M. Hosenfeld, Head
Analytical Chemistry Section
Apnjcpved:
(hyk
mn E. Going, Director
Chemical Sciences Department
-------
TABLE OF CONTENTS
I. Summary 1
A. Background and Objectives 1
B. Scope 1
C. Data Collected 1
D. Major Findings 1
E. Conclusions 4
II. Introduction 4
III. Experimental Methods 5
A. Study Participants 5
B. Rationale for Selection of Study Items 5
C. Questionnaires 6
IV. Results and Discussion 7
A. Study Population 7
B. PCP Concentrations in Homes 8
C. Biological PCP Concentrations 12
D. Relationships Between Selected PCP Measurements. 19
E. Relationship Between Serum and Urinary PCP
Concentrations and Clinical Findings 21
F. Comparison of Results for Participants in the
1980 and 1984 Studies 22
V. References 24
iii
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LIST OF TABLES
Table Page
1 Summary of PCP Concentrations (ng/L) in Air by House
Treatment Category 10
2 Wood PCP Concentration (ng/g Wood) by House Treatment
Category 11
3 Summary of Surface PCP Concentrations (ng/100 cm2)
Determined from Wipe Samples of Surfaces "Adjacent"
to Wood Core Samples by House Treatment Category. ... 13
4 Summary of Surface PCP Concentrations (in ng/100. cm2)
Determined from Wipes of "Exposure" Surfaces by
House Treatment Category -,. . . 14
5 Serum PCP Concentration (ng/mL) by House Treatment
Category. . . ^ 15
6 Total Urinary PCP Concentration (mg/g Creatinine) by
House Treatment Category 17
7 Free Urinary PCP Concentration (mg/g Creatinine) by
House Treatment Category ,3, 18
, , ' --V
8 Association of Age Groups with Biologic PCP
Concentrations Adjusted for Household . . 20
IV
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I. SUMMARY
A. Background and Objectives
The U.S. Environmental Protection Agency's Office of Toxic Substances
conducted a survey of pentachlorophenol (PCP) treated log homes and their oc-
cupants at the request of the Kentucky Department for Health Services. This
study was conducted because of the possible exposure of log home residents to
PCP from the treated logs. The results of this study are presented in this
report.
The primary objectives of this study were (a) to determine the ex-
tent of environmental levels of PCP in log homes which had been treated with
PCP; (b) to determine the extent of biological exposure in log homes treated
with PCP; and (c) to examine the relationship between selected health vari-
ables and biological PCP concentrations. These health variables and biolog-
ical PCP concentrations were analyzed in a search for possible effects of
residues in a PCP treated log home.
B. Scope
The target population was the residents of log homes that had been
treated with PCP, located in the State of Kentucky and that had been sampled
in an earlier study conducted in 1980. Twelve of these previous study homes
were included in the present study together with nine homes constructed from
logs not treated with PCP according to the manufacturer.
C. Data Collected
Environmental and medical data were collected. An environmental
evaluation of each of the 21 homes was conducted. The evaluation consisted
of house treatment questionnaire administered to the head of the household,
and collection of wood core, surface wipes (2), indoor air samples (3), and
water samples. All samples were examined for PCP concentration.
The medical evaluation consisted of a health history questionnaire;
a directed, standardized physical examination with particular attention to
abnormalities of the skin and nervous system and the presence or absence of
lymphoadenopathy. Sample collection from the log home residents consisted of
blood drawing for serum PCP concentration, serum liver and renal function
tests, and tests for blood morphology and abnormalities, and a collection of
the first voided urine of the day for tests for renal and adrenal dysfunction,
enzyme induction and urinary PCP—both free and conjugated. All of the bi-
ological samples were collected within 18 h of the environmental sampling in
each each study participant home.
0. Major Findings
Following are the major findings of this study.
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All housiv, examined In this study had some levels of PCP In the logs.
There were actually «lx treatment categories in which the 21 studied log homes
fell. Thr* highest IMJC levels wert- found In the manufacturer treated homes
(4); next |n t.he manufacturer treated homes and '.ubsfqucntly sealed (4); next
in the manufacturer treated -md subsequent, ly <>eali>
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The distribution of serum PCP, urinary free PCP tnd urinary total
PCP concentrations were significantly different among the house traatmant
categories. Wharaai tha axtarlor traatad and never-treated categories did
not dlffar significantly from aach other, concentration* In tha manufacturer
traatad categories ware mostly significantly higher, Serum PCP concentra-
tions did not differ significantly with subject age group but both free and
total urinary PCP concentrations were significantly different among the ex-
amined age groupa (4 to 7, 8 to 12, and over 12 yr old) with the highest con-
centrations In tha youngest age group and tha lowest concentrations 1n the
over 12 age group.
Mean serum, free urinary and total urinary PCP concentrations for
households, adjusted for the age group distribution 1n the household, were
highly correlated with each other. Tht environmental PCP concentrations
(wood core, air, surface wipe) were highly correlated (or « < 0.03)w1th bio-
logical PCP concentrations (serum, free urinary and total urinary) for house-
holds adjusted for the age group distribution 1n the household.
The age group adjusted association between estimated mean serum and
total urinary PCP concentrations and certain possible health effects of PCP
determined by responses to the medical questionnaire were examined. No sig-
nificant (a • 0.05) associations were seen between the PCP concentration and
the reported history of eczema, acne, tumor or lump removed, rash or derma-
titis In the past year, currently taking medication, fever at least once or
more than once within the last 6 mo, unexplained weight loss 1n the last 6
mo, Irritation of ayes, tearing of eyes, or swelling of eyelids since occupy-
ing the present house.
The association between mean serum PCP and total urinary PCP con-
centrations for households and certain biochemical variables for tha house-
hold, adjusted for age group distribution In the household, were explored.
No significant association was seen for liver function tests, a test of mlcro-
somal enzyme Induction, and a renal function test. Statistically significant
(a » 0.05) negative associations were seen for serum total protein and serum
creatlnlne and both biologic PCP concentrations. The reason for these nega-
tive associations was unclear; several explanations are possible and they
probably do not reflect toxic effects.
The age group adjusted association between estimated mean serum and
urinary total PCP concentrations and the presence or absence of lymphadeno-
pathy or of abnormalities of skin or neurologic examination was studied.
There was no significant association with lymphadenopathy or neurologic ab-
normalities. There was a statistically significant (a * 0.05) positive asso-
ciation between the presence of skin abnormalities noted during the physical
examination and PCP concentrations. It could not be determined whether this
reflected more absorption of PCP through abnormal skin, effects of PCP on the
skin, or some other factor.
A comparison of results from the same log home residents who par-
ticipated 1n the 1980 and 1984 surveys was made to determine 1f there were
differences. The concentration of PCP In serum was significantly lower In
1984 than In 1980 but the urinary levels were the same for both studies, No
differences were seen for the clinical biochemistry tests performed 1n both
studies.
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E. Conclusions
Following are the major conclusions of the study.
1. PCP found in the indoor air of the log homes is a result of
treatment of the logs with PCP.
2. The environmental levels of PCP in the log home are related to
the type and degree of PCP treatment of the logs.
3. Cisterns in PCP treated log homes are a source of PCP to humans
if the water is used for drinking purposes.
4. A source of the PCP found in the study participants was the
PCP treated logs.
5. Children under age 12 living in PCP treated log homes excrete
PCP at the highest rate as compared to over 12 age group.
6. The presence of skin abnormalities may be indicative of PCP ex-
posure.
II. INTRODUCTION
In 1980, as part of an investigation conducted by the United States
Environmental Protection Agency (EPA) and the Centers for Disease Control
(CDC) into the possible health effects of human exposure to pentachlorophenol
(PCP)-treated wood used in packing crates, a family living in a commercially
manufactured log home in Kentucky was found to have elevated serum and urine
levels of PCP as compared to control individuals (Lakings et al. 1980). A
subsequent study conducted by CDC and the Kentucky Department of Human
Services included retesting some members of the index family along with 29
volunteer residents of other PCP-treated log homes, and 13 controls who did
not inhabit PCP-treated log homes. Selected clinical and biochemical mea-
surements were performed. Results demonstrated significant differences in
serum and urinary PCP concentrations between residents of PCP-treated homes
and controls. Inter-family differences in residents of PCP-treated homes
suggested that there was a dose-response relationship between the amount of
time spent in the home and serum PCP concentrations and that children experi-
enced the highest biological PCP concentrations (CDC, 1981).
A medical follow-up study of those persons previously identified as
inhabiting PCP-treated homes in 1980 and living in Kentucky was conducted by
Midwest Research Institute (MRI) and the Johns Hopkins University Center for
Occupational and Environmental Health (COEH) for EPA in response to a request
from the Kentucky Department of Human Services. A comparison population of
persons inhabiting log homes which had not been constructed of PCP-treated
logs were studied concurrently. The control population was as similar as
possible in demographic parameters and geographic location to the group
inhabiting PCP-treated log homes.
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401 M ST., S.W., Tl-7 '
This study included, as far as possible, the blood salHp^fngrand
analysis procedures carried out in the 1980 study. In addition, several com-
ponents were added, particularly environmental measurements of PCP in log
homes and house treatment history. Also, medical questionnaires, additional
clinical biochemistries, and medical examinations were added. Efforts were
made to duplicate methods of chemical analysis to ensure compatibility of
results with existing data from the 1981 study.
III. EXPERIMENTAL METHODS
The procedures used to identify candidate houses, and recruit the
occupants, to determine rationale for collecting environmental and biological
samples are discussed along with questionnaires developed.
A. Study Participants
There were 29 family members, representing 17 families, in the 1980
study living in PCP-treated homes in Kentucky. All were volunteers who had
responded to articles in newspapers, radio, and television who contacted
their State or county health departments, and were directed to CDC. EPA was
provided with the names and addresses of these households by the Kentucky De-
partment of Human Services.
In order to obtain a comparison population living in log homes not
treated with PCP, contact was made with log home manufacturers and dealers.
The names and addresses of untreated log homeowners who were within 100 miles
of Louisville were obtained from log home builders who were listed in a guide
to the industry. These households were contacted and recruited.
B. Rationale for Selection of Study Items
1. Environmental Measurements
a. Air PCP Concenrations
Air samples were collected in the home of every study partici-
pant to estimate the family member's PCP intake via the respiratory route.
b. Wood PCP Concentrations
Wood core samples of logs on the interior of the home were
collected in each study home to confirm statements gathered on the Environ-
mental Questionnaire concerning the preservative treatment history of each
log home included in the study. The wood core samples provided an indica-
tor of the PCP concentration.
c. Surface Wipe PCP Concentrations
Surface wipe samples were collected from interior log surfaces
in every home in the study to estimate the potential for PCP dermal exposure
of log home residents.
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d. Drinking Water PCP Concentrations
A tap water sample was collected from each home to estimate
each participant family's PCP intake via the water used for drinking, bathing,
and cooking.
2. Clinical Studies
The following clinical laboratory tests were selected to assist in
determining the health status of the individuals participating in the study.
Tests were selected on the basis of clinical usefulness for the detection of
potential effects of PCP as well as their use in the 1980 study by CDC.
a. Laboratory Tests on Blood and/or Serum
• Hemoglobin, henatocrit, total white blood cell count and
differential count (tests for blood morphology and abnor-
malities).
• Serum lactic dehydrogenase, alkaline phosphatase, gamma
glutamyl transpeptidase, glutamic oxaloacetic transferase,
glutanic pyruvic transaminase, total bilirubin, total pro-
tein, albumin (tests for liver function), blood urea nitro-
gen and creatinine (tests for renal function).
- Serum PCP level.
b. Laboratory Tests on Urine
• Urinalysis (tests for renal dysfunction)
• 6-Beta-hydroxycortisol and free urinary cortisol (tests
for adrenal dysfunction)
• Creatfnine (test for renal dysfunction and used to normalize
urinary PCP concentrations).
• Urinary PCP-free and conjugated
3. Physical Examinations
The physical evaluations consisted of standardized hepatic, neuro-
logic, and deraatologic examinations. This type of directed physical exam-
ination was selected on the basis of reported health effects of PCP.
C, Questionnaires
The Environmental Questionnaire was designed to quantify factors
which *ere thought to possibly affect PCP concentrations in log homes or
which could be used to help understand otherwise unexplained clinical find-
ings. Questions included in the Environmental Questionnaire focused on fea-
tures of the log home and occupant practices or habits which might affect
environmental measurements.
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The Medical Questionnaire was administered by a trained interviewer
to obtain information on:
• Possible confounding factors that might affect the results of
the laboratory investigations, including smoking and alcohol
habits, drug consumption, and personal history of relevant
diseases;
• Other sources of exposure to PCP;
• Approximate amounts of time spent in the home for the 48 h prior
to sampling;
• Selected symptoms potentially associated with exposures to PCP.
IV. RESULTS AND DISCUSSION
A. Study Population
Field studies were conducted in the 21 recruited homes during the
11 day period from February 15 to 25, 1984.
1. House Characteristics
It was originally anticipated that the houses would fall into two
groups according to PCP .treatment. In fact, analysis of the responses from
the environmental questionnaire and a review of the results of PCP concen-
trations from the wood core samples revealed that all but four of the sup-
posedly untreated homes had been treated with PCP in some manner.
As a result, the following house treatment categories were devel-
oped. As will be seen later, the wood core PCP concentration data indicated
that this was a useful categorization,
Treated: Included all log homes which were reported to have been
treated by the manufacturer with a PCP-containing wood preservative in a man-
ner which immersed the entire log (either by dipping or pressure treating)
and had not subsequently been sealed or chemically neutralized. This process
resulted in both the interior and exterior surfaces of the house being PCP-
treated. There were four houses so treated in the study population.
Treated and Sealed: Included all log homes which were reported to
have been treated wi th a PCP'containing wood preservative in the manner de-
scribed in the "Treated" category (above) and in which the interior surfaces
of the house had been subsequently treated with some type of sealant. The
four houses included in this category had the majority of the interior log
surfaces treated with polyurethane (two houses) or varnish (two houses).
Treated and Neutralized: Included all log homes which were reported
to have been treated with a PCP-containing wood preservative in the manner
described in the "Treated" category (above) and in which the interior surfaces
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of the house had been treated with a chemical agent designed to react with,
and thereby neutralize, PCP in the wood. The three houses included in this
category had the majority of the interior log surfaces treated with Permatox-
Pentite®, manufactured and distributed by Chapman Chemical Corporation (Memphis,
Tennessee) for this expressed purpose. Although the specifics of the chemical
reaction are proprietary, the mode of action was described as chemical neutrali-
zation.
Treated and Sealed and Neutralized: Included all log homes which
were reported to have been treated with a PCP-containing wood preservative in
the manner described in the "Treated" category (above) and treated with a
sealant in the manner described in the "Treated and Sealed" category (above)
and treated with a neutralizer in the manner described in the "Treated and
Neutralized" category (above). One house received both treatments. Although
the order of treatment was not stated by the homeowner, it is presumed that
the logs were neutralized and then sealed.
Exterior Treatment: Included all log homes which were reported to
have been treated with a PCP-containing wood preservative by spray-application
of the preservative to the exterior surfaces of the house at the time of con-
struction. Interior surfaces of homes included in this category were reported
not to have been treated with a PCP-containing wood preservative. There were
four houses so treated in the study population.
Never Treated: Included all log homes which had been reported to
have never been treated on any surface with a PCP-containing wood preserva-
tive. There were four such houses in the study population.
Treatment Unknown: For one house the treatment history was unknown
by the original owner-occupant-builder. Analysis of the wood core samples
collected from the house confirmed that the house had been treated with a PCP-
containing wood preservative, but the method of application was unknown and
it was not known whether it had been subsequently sealed and/or neutralized.
2. Personal Characteristics of Study Participants
A total of 72 individuals took part in the study, although there
were 80 inhabitants above the age of 4 that resided in the study houses. One
participant did not complete the study questionnaire but did -provide some sam-
ples so that most data is reported for only 71 participants. The ages of par-
ticipants ranged from 4 to 66, with a mean age of 26.1 and a median age of
30. There was an even distribution of male and female participants. There
were 50 participants aged greater than 12, 11 aged from 8-12, and 10 aged
from 4-7. All participants were white.
B. PCP Concentrations in Homes
I. Air Sampling Results
Three air samples were collected in every home in the study popula-
tion, together with appropriate quality control samples (i.e., blank, duplicate
or spike) in selected homes, according to the protocol previously described.
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PCP was detected in 62 of the 63 samples collected. Detected con-
centrations ranged from 0.001 ng/L to 0.904 ng/L but were fairly consistent
within any given house, usually varying by no more than a factor of two.
The PCP residues in air are summarized by house treatment category
in Table 1. As seen on the table, and confirmed by statistical analyses, air
concentrations of PCP for Never Treated houses are significantly lower than
those for all treated houses. Among treated houses, the air concentrations
for Treated and Sealed houses are significantly higher than those for houses
that were Treated and Neutralized or had External Treatment. Therefore, it
is, thus, concluded that there are real and significant differences in the
air concentrations of PCP among several of the treatment categories.
2. Wood Core Sample Results
From 12 to 21 individual wood core samples were collected from the
interior surfaces of logs in every home and subsequently composited to a sin-
gle sample for each home.
PCP was detected in the wood core samples from all 21 houses in the
study population. Detected concentrations ranged from 44 ng PCP/g wood to
438,500 ng PCP/g wood. The wood core PCP concentrations appeared to be dis-
tributed in a manner which corresponded with the different methods of PCP
treatment which had been used in the study houses as stated by the homeowner.
As a result, the six categories of house PCP treatment indicated earlier were
used in further analysis. The never treated homes had PCP concentrations as
a possible result of the logging industry spraying stockpiled logs with PCP
to prevent mold and mildew.
Concentrations of PCP in wood are summarized by house treatment
category in Table 2. As seen in the table, and confirmed by statistical
analyses, the mean wood PCP concentration in the Never Treated category was
significantly different from that of each of the treated categories. There
were no statistically significant differences between those categories which
had been treated with PCP. The number of houses in each treatment group was
small, however, and it is quite likely that given the same geometric means
from a larger study population, there may have been statistically significant
differences between the treatment groups.
3. Surface Wipe Sampling Results
Two composited sets of surface wipe samples were collected from the
interior surfaces of logs in every home, together with appropriate quality
control duplicates in selected homes. One of these sets, designated as "ad-
jacent" samples, was collected from logs immediately contiguous to wood core
samples for the purpose of determining how accurately a surface wipe sample
reflected the PCP concentration in the underlying wood. The second set,
designated "exposure" samples, was collected from surfaces throughout the
house which were thought to be frequently contacted by occupants of the home.
This set was collected in order to help estimate the potential dermal expo-
sure to PCP.
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Table 1. Summary of PCP Concentrations (ng/L) in Air
by House Treatment Category
Treatment
category
T
TS
TN
TSN
XT
NT
TU
ALL
N
4
4
3
1
4
4
1
21
Median
0.421
0.433
0.068
0.209
0.072
0.010
0.016
0.083
Range
0.090 -
0.185 -
0.062 -
0.209 -
0.028 -
0.003 -
0.016 -
0.003 -
0.810
0.758
0.083
0.209
0.113
0.019
0.016
0.810
Geometric
mean
0.314
0.383
0.071
0.209
0.064
0.007
0.016
0.080
95% Confidence
interval
0.116 -
0.195 -
0.060 -
-
0.036 -
0.003 -
-
0.040 -
0.850
0.751
0.084
0.112
0.030
0.162
aT=treated; TS=treated and sealed; TN=treated and neutralized; TSN=treated,
sealed, and neutralized; XT=exterior treated; NT=never treated; TU=treatment
unknown.
10
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Table 2. Wood PCP Concentration (ng/g Wood) by
House Treatment Category
Treatment
category
T
TS
TN
TSN
XT
NT
TU
N
4
4
3
1
4
4
1
Median
78,800
190,000
45,000
102,000
11,300
110
28,000
Range
8,000 -
101,000 -
8,000 -
102,000 -
6,000 -
44 -
28,000 -
438,000
340,000
113,000
102,000
33,400
1,600
28,000
Geometric
mean
53,600
183,000
34,400
102,000
12,500
159
28,000
95% Confidence
interval
8,650 - 330,000
106,000 - 316,000
7,510 - 157,000
-
6,040 - 25,900
32 - 496
-
ALL 21 28,000 44 - 438,000 15,900 5,020 - 50,200
11
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PCP was detected in all 21 of the "adjacent" wipe samples (Table 3)
and in 20 of the 21 "exposure" wipe samples (Table 4). The "adjacent" wipe
samples usually showed greater PCP concentration than the composited "expo-
sure" wipe samples for a given house. This result is expected as all "adja-
cent" wipe samples were taken from the source of PCP contamination in the
house (the logs), while the "exposure" wipe samples were taken from fre-
quently contacted surfaces which may or may not have been contaminated with
PCP.
Statistical analyses of PCP concentrations in "adjacent" wipe samples
showed Never Treated houses differed statistically from Treated, Treated and
Sealed, and Treated and Sealed and Neutralized houses. In addition, houses
which received External Treatment differed only from Treated and Sealed houses.
Statistical analyses of PCP concentrations in "exposure" wipe sam-
ples showed that only the highest (Treated) and lowest (Never Treated) treat-
ment categories were statistically different.
4. Drinking Water Sampling Results
PCP was detected in only 4 of the 21 homes in the study population.
The PCP residues detected in these four homes ranged from 0.2 ng/L to 1.0 ng/L.
In all other homes the PCP concentration was below the analytical limit of
detection, 0.2 ng/L.
Analysis of the presence of PCP in drinking water by house treat-
ment category showed that all four of the homes in which PCP was detected had
been treated. The distribution was across house treatment categories: one
Treated and Sealed and Neutralized (0.2 ng/L), one Exterior Treatment
(0.3 ng/L), one Treated and Sealed (1.0 ng/L), and one which was treated in
an unknown manner (0.6 ng/L). In all cases, PCP contaminated drinking water
came from a house that utilized a cistern as the source of water. Statis-
tical analysis of this distribution by source of water showed this relation-
ship between source of water and the presence of PCP contamination of that
water to be significant.
C. Biological PCP Concentrations
1. Serum and Urine PCP Concentrations
Blood samples were collected and the concentration of PCP deter-
mined. The range, median, geometric means and 95% confidence intervals for
serum PCP concentrations by house treatment category are given in Table 5.
Statistical analysis showed that there were significant differences among the
house treatment categories; specifically, the mean household serum PCP con-
centrations for the Exterior Treatment and Never Treated house treatment
categories, while not differing significantly from each other, differed sig-
nificant"^ from the means of the other four treatment categories. The serum
PCP concentration in the Exterior treatment category was almost twice as high
as that in the Never Treated category, and those of the other four categories
were from 4 to 7 times higher than the Never Treated category.
12
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Table 3. Summary of Surface PCP Concentrations (ng/100 cm2) Determined
from Wipe Samples of Surfaces "Adjacent" to Wood Core
Samples by House Treatment Category
Treatment
category
T
TS
TN
TSN
XT
NT
TU
N
4
4
3
1
4
4
1
Medi an
402
1040
214
227
113
43
48
Range
345 -
184 -
82.6 -
227 -
82.1 -
6.7 -
48 -
2290
1231
276
227
198
108
48
Geometric
mean
596
699
171
227
121
34.9
48
95% Confidence
interval
245 - 1450
289 - 1690
83.8 - 348
-
84.9 - 173
11.5 - 106
-
ALL 21 198 6.7 - 2290 187 106 - 333
13
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Table 4. Summary of Surface PCP Concentrations (in ng/100 cm2) Determined
from Wipes of "Exposure" Surfaces by House Treatment Category
Treatment
category
T
TS
TN
TSN
XT
NT
TU
N
4
4
3
1
4
4
1
Median
318.0
232.9
147.0
172.0
57.1
43.9
10.0
Range
244 -
81.5 -
92.9 -
172 -
12.3 -
ND -
10.0 -
400
427
192
172
233
62.5
10.0
Geometri c
mean
316
195
139
172
56.9
18.2
10.0
95% Confidence
interval
259 -
88.6 -
92.1 -
-
18.1 -
2.7 -
-
386
431
210
179
130
ALL 21 117 ND - 427 89.6 47.9 - 167
14
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Table 5. Serum PCP Concentration (ng/mL) by House Treatment Category*
Treatment
category
T
TS
TN
TSN
XT
NT
TU
ALL
N
13
12
11
5
12
8
4
65b
Range
32.5 -
21.7 -
27.7 -
92.0 -
9.4 -
7.0 -
16.0 -
7.0 -
160
151
163
168
55.7
23.3
25.1
168
Median
106
111
65.5
108
23.0
11.6
18.3
54.0
Geometric
mean
95.9
81.1
69.9
114
22.8
11.2
19.1
47.6
95% Confidence
interval
74.2
55.9
47.5
93.3
17.9
8.3
13.1
37.8 -
- 124
- 118
- 102
- 140
- 29.1
- 15.1
- 27.9
59.9
.Limit of detection = 0.25 ng/mL.
Serum PCP concentration is unknown for seven participants because the
specimen could not be collected.
-------
Two urine PCP concentrations were measured for each individual:
the concentration of free PCP in urine and the total PCP concentration which
is considered a more reliable indicator of PCP total excretion. Urinary PCP
concentrations were normalized for potential variations in urine concentra-
tion by expressing the excretion in terms of mg PCP/g of creatinine expected.
Table 6 provides summary statistics for total urinary PCP concentrations by
house treatment category. Statistical analysis showed that there were sig-
nificant differences among the house treatment categories; specifically, the
mean values for the category Treated and the catetogry Treated, Sealed and
Neutralized were significantly higher than the mean for Exterior Treatment.
The means for all other categories but the Exterior Treatment category were
significantly higher than the mean for the Never Treated category. The mean
total urinary PCP concentrations in the Exterior Treatment category were 3
times as high as those in the Never Treated category. Those of the other
four categories were from 5 to 11 times higher than the Never Treated category.
Table 7 shows the summary statistics for free urinary PCP concen-
trations by house treatment category. For the population as a whole the
median and geometric mean concentrations of urinary free PCP were, respec-
tively, 48% and 43% lower than those found for urinary total PCP concentra-
tions. Statistical analysis showed that there were significant differences
among the house treatment categories; specifically, the mean household un-
hydrolyzed urine PCP concentrations for the Treated category differed sig-
nificantly from the Exterior Treatment category, and the Treated, Treated and
Sealed, and Treated and Neutralized differed significantly from the Never
Treated category. By analogy then, the Exterior Treatment and the Never
Treated categories are not different from one another.
These data clearly indicate that blood and urine PCP concentrations
of residents in PCP-treated log homes were considerably higher than in resi-
dents of log houses not treated with PCP.
2. Influence of Age on Biological PCP Concentrations
In evaluating biological PCP concentrations it was considered that
age was likely to be an important covariable. This is due to both behavioral
and physiological differences between children and adults. Young children
tend to spend more time than many adults in the house and have play activ-
ities which are likely to bring them into closer contact with potentially PCP
contaminated surfaces such as floors. By the teenage years, more adult pat-
terns of behavior in these respects are generally established. Physiolog-
ically there are differences with age in the absorption, distribution and
possibly metabolism of xenobiotics like PCP- These differences include
higher ventilation rates in children relative to body mass, larger relative
surface area available in children for percutaneous absorption, higher meta-
bolic rates in children, and differences in the relative proportions of dif-
ferent tissues into which xenobiotics might be distributed. Once puberty is
reached the.se relationships tend to remain relatively stable throughout adult
age.
16
-------
Table 6. Total Urinary PCP Concentration (mg/g Creatinine)
by House Treatment Category
Treatment
category N
T
TS
TN
TSN
XT
NT
TU
ALL
13
12
12
5
12
8
3
65a
Range
0.012 -
0.006 -
0.008 -
0.028 -
0.005 -
0.000 -
0.006 -
0.000 -
0.179
0.139
0.082
0.134
0.039
0.013
0.010
0.179
Median
0.036
0.028
0.026
0.056
0.015
0.004
0.006
0.021
Geometric
mean
0.044
0.030
0.026
0.060
0.009
0.004
0.007
0.021
95% Confidence
interval
0.026 -
0.017 -
0.018 -
0.035 -
0.007 -
0.003 -
0.004 -
0.016 -
0.074
0.052
0.038
0.100
0.013
0.006
0.012
0.028
aTotal urinary PCP concentration corrected for creatinine is unkown
for seven participants because no specimen was received.
-------
Table 7. Free Urinary PCP Concentration (mg/g Creat1n1ne)
by House Treatment Category
Treatment
category
T
TS
TN
TSN
XT
NT
TU
N
13
12
12
5
12
8
3
Range
0.007 -
0.003 -
0.006 -
0.011 -
0.003 -
0.002 -
0.001 -
0.120
0.052
0.101
0.028
0.027
0.006
0.007
Median
0.034
0.012
0.016
0.018
0.009
0.005
0.002
Geometric
mean
0.031
0.013
0.017
0.018
0.009
0.004
0.003
95% Confidence
Interval
0.018 -
0.007 -
0.011 -
0.013 -
0.007 -
0.003 -
0.000 -
0.052
0.022
0.026
0.025
0.013
0.005
0.014
ALL 65a 0.001 - 0.120 0.011 0.012 0.009 - 0.016
aFree urinary PCP concentration corrected for creatinlne is unknown
for seven participants because no specimen was received.
18
-------
In order to account for possible differences 1n age, study partici-
pants were considered 1n three age groups: 4 to 7, 8 to 12 and over 12 yr
old. As there were no Individuals aged less than 4 or more than 65 yr, 1t
was not necessary to consider the very young or very old 1n our analyses.
Table 8 shows the association of age group with biologic PCP con-
centrations, adjusted for household. The serum PCP concentration was slightly
higher 1n the younger age group but the differences among the groups were not
statistically significant. Highly significant differences among the groups
were seen for urinary free and total PCP concentrations, with the highest
values in the 4 to 7 age group and the lowest in the over 12 age group, whose
mean values were less than half those of the youngest group.
0. Relationships Between Selected PCP Measurements
1. Correlations Within Environmental Samples
Statistical analysis of the measured concentrations of PCP in air,
wood cores, "adjacent" and "exposure" surface wipe samples was performed.
All values were highly correlated and all the correlations were statistically
significant. PCP concentrations measured in the air of the log homes were
highly correlated with the PCP concentration in the wood core samples. This
suggests that PCP 1s continually vaporized from the logs to the air. Air con-
centrations were measured under a narrow range of temperatures and with closed
windows defined by the study protocol to assess sample comparability; under
other conditions the association may not be as strong.
PCP concentrations measured in "adjacent" wipe samples were also
found to be highly correlated with the wood core PCP concentration and the
air PCP concentration. This presumably reflects that the wood surface is the
interface (i.e., site of vaporization) between the log and air.
PCP concentrations measured in "exposure" wipe samples were also
significantly correlated with concentrations of PCP measured in air and wood
samples, although the correlations were not as strong as in the case of the
"adjacent" wipe samples. This is not unexpected since the "exposure" wipe
samples reflect concentrations on various surfaces throughout the house rather
than just the interface between logs and air. "Exposure" wipe samples were
collected from both log and other surfaces thought to be frequently contacted
by inhabitants of the house. Many of these surfaces may not have been PCP-
treated, although they may have become PCP-contaminated through condensation.
Other surfaces such as around light switches, door jabs, and window frames
probably were touched and may have been treated with PCP. As a result the
correlation between "exposure" wipe samples and other environmental measures
of exposure would be expected to be lower because of the sample being "diluted"
with possible non-PCP treated surfaces.
2. Relationship Between House Treatment History and Air PCP Con-
centrations After Adjustment for Wood Core PCP Concentrations
The effectiveness of the sealing and/or neutralizing PCP treated
logs in reducing air PCP concentrations was explored.
19
-------
Table 8. Association of Age Groups with Biologic PCP Concentrations
Adjusted for Household
Biological
PCP measure
Serum PCP
(ng/mL)
Urinary free
PCP (mg/g
creatlnlne)
Urinary total
PCP (mg/g
creatlnlne)
Number of
Age participants
group 1n age group
4-7
8-12
> 12
4-7
8-12
> 12
4-7
8-12
> 12
10
11
50
10
11
50
10
11
50
Geometric
least squares
means
51.5
38,0
41.1
0.027
0.019
0.010
0,036
0,029
0.017
Ratio of
means
1,00
0.74
0,80
1,00
0,70
0,37
1.00
0.81
0,47
Overall^
P-value
0.194
0.0001
0,004
^Compared with 4 to 7 yr old
P-value associated with F-t<
age group.
•test for differences among age groups.
Results of palrwlse comparison of age groups at the 0.05 level for
urinary free and urinary total PCP: Age group > 12 differs significantly
from age groups 4-7 and 8-12.
20
-------
When air PCP concentrations were adjusted for differences In wood
core PCP concentrations, sealing of th« Interior surface (with polyurethana
or varnish) of the log homes Included 1n the study population did not signif-
icantly reduce the air PCP concentration. A1r concentrations were, 1n fact,
slightly (although not statistically) elevated. A1r PCP residues In homes
constructed of treated logs which had subsequently been neutralized (with
Permatox-Pentlte) were found to be 44% of the expected concentration had the
logs not been neutralized. This difference was statistically significant
(p • 0.039),
3. Relationships Between Environmental and Biological PCP Concen-
tratlons
Statistical analysis was performed between various environmental
PCP concentrations (wood core, air, "exposure" surface wipes) and biological
PCP concentrations (serum, free urinary, and total urinary) for household
(weighted by the number of people 1n the household) and adjusted for age
group distribution In the household. All studied correlations were strongly
positive and statistically significant.
E, Relationship Between Serum and Urinary PCP Concentrations and
Clinical Findings
I. Questionnaire Responses
The significance of the age group, serum PCP or total urinary PCP
concentrations and certain questionnaire responses was examined. There were
no significant differences for any of the health questions.
2. Clinical Laboratory Evaluations
The association between serum biochemical results and serum, or
total urinary PCP concentrations was evaluated. The association with total
urinary PCP was examined both with and without correction for the urinary ex-
cretion of creatlnlne. Most values, Including various serum liver function
tests (albumin, b1Hrub1n, alkaline phosphatase, glutamlc oxaloacetlc trans-
ferase, glutamlc pyruvate transamlnase, lactic dehydrogenase and gamma
glutamyl transpeptldase), a test of mlcrosomal enzyme induction (ratio of
urinary 6-beta-hydroxycort1sol to free cortlsol), and a renal function test
(blood urea nitrogen) were not different among the groups.
There was a statistically significant negative association between
the serum total protein concentration and both the serum PCP and the urine
total PCP concentrations. The total serum protein concentrations measured a
large number of proteins and the data did not allow determination of what
fraction or fractions of proteins might be responsible for this association.
The reason, 1f any, for this apparent association remains obscure and needs
further exploration. Serum albumin, however, which constitutes the bulk of
serum protein, was not statistically significantly associated with serum PCP
or urinary PCP concentration.
21
-------
There was a curious and not readily explained strong negative asso-
ciation between both the serum PCP and urinary PCP concentrations with the
serum creatinine concentration. Both associations were highly statistically
significant. The serum creatinine is an indicator, among other things, of
renal function. If PCP nephrotoxicity were occurring the creatine level would
be expected to rise with increasing PCP concentrations, but the reverse is
the case here so that nephrotoxicity is not a tenable explanation.
The production of creatinine and therefore its concentration in
serum, given normal urinary function, is a function of body muscle mass. It
is conceivable that the negative correlation between PCP concentrations and
serum creatinine reflects some alteration in distribution of PCP within the
tissues of exposed individuals, but this explanation remains conjectural.
3. Physical Examination
No significant difference was seen for the neurologic examination
or for lymphadenopathy. However, both the estimated mean PCP serum and esti-
mated mean total urinary PCP concentration for those with abnormal skin exam-
inations were statistically significantly higher than for those with normal
skin examinations. It could not be determined whether there may have been
more absorption of PCP through the skin as a result of pre-existing skin ab-
normalities, whether the PCP might have caused skin abnormalities, or whether
there was some other factor accounting for both skin abnormalities and in-
creased biologic PCP concentrations.
F. Comparison of Results for Participants in the 1980 and 1984 Studies
It was possible to compare biochemical indicators of organ func-
tions between 1980 and 1984 in those participants who were studied at both
times. Because of substantial variations in these indicators in children and
changes in age which occurred over the 4-yr period such comparisons will only
be valid in adults.
The results of longitudinal analysis showed that the serum PCP con-
centrations were significantly lower by a factor of almost 5 in 1984 compared
with 1980. However, the urinary unhydrolyzed PCP concentrations were somewhat
higher in 1984, although the differences were not statistically significant.
A ready explanation for these differences is not apparent. Both the collec-
tion of specimens and the laboratory analysis were performed by different
groups in the two studies so that differences in sampling and analysis cannot
be excluded as responsible for the variations. It is also possible that sub-
stantial reduction in PCP exposure has occurred over the 4-yr interval but
that for some unaccountable reason, it is not reflected in the urinary un-
hydrolyzed PCP concentrations. The results of serum biochemistries did not
differ between the two years and the mean values obtained were quite similar
on both occasions.
22
-------
V. REFERENCES
Chronic Diseases Division, Centers for Disease Control. 1981 (September).
Internal memo to Director of Centers for Disease Control. Pentachlorophenol
wood preservative exposure in residents of log homes. Louisville, Kentucky,
Public Health Service-CDC-Atlanta. EPA 80-60-2.
takings, D et al. 1980. Determination of pentachlorophenol and hexachloro-
benzene residues. Final Report, EPA Contract 68-01-5915, Task 12.
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5027: -1 01 -,
REPORT DOCUMENTATION >_«PO«T NO. 2.
PAGE EPA-560/5-87-001A
4. Title and Subtitle
Pentachlorophenol in Log Homes: A Study of Environmental and
Clinical Aspects - Executive Summary
7. Authorts)
Hosenfeld, John M.
V. Performing Organization Nam* and Address
Midwest Research Institute
425 Volker Boulevard
Kansas City, MO 64110
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
Office of Toxic Substances
Exposure Evaluation Division, TS 798
4ofM Street, SW
Washinoton. DC 20460
5. Report Date
December 1986
6.
S. Performing Organisation Rept. No.
10. Praieet/Taak/Work Unit No.
Task 1 1
11. Contract(C) or Qrant(G) No.
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