United States
              Environmental Protection
              Agency
Atmospheric Research and
Exposure Assessment Laboratory
Research Triangle Park, NC 27711
              Research and Development
EPA/600/SR-94/189  November 1994
EPA      Project  Summary
              Development and  Evaluation of
              Monitoring Methods  for
              Polycyclic  Aromatic
              Hydrocarbons  in  House  Dust  and
              Track-In Soil
              Jane C. Chuang, Patrick J. Callahan, Vanessa Katona, and Sydney M. Gordon
                The analytical method for determin-
              ing polycyclic aromatic hydrocarbons
              (PAHs) in dust and soil consists of
              sonication with 10 mL of hexane (C6)
              for two 30-min extractions and analy-
              sis of the C6 extract by gas chromatog-
              raphy/mass spectrometry (GC/MS). The
              analytical method for determining poly-
              chlorinated biphenyls (PCBs) in dust
              and soil  involves sonication  with 10
              mL of  10 percent ether in C6 for two
              10-min extractions, silica gel column
              chromatography, and  analysis of the
              target fraction by GC/MS. Quantitative
              recoveries of spiked perdeuterated PAH
              and 13C-!abeled PCB are obtained us-
              ing the above methods.
               The sum of the concentrations of all
              target PAH In the house dust samples
              evaluated in this study ranged from 16
              to 580 ppm. Higher concentrations were
              observed in entryway soil samples, and
              the sum of the concentrations of target
              PAH ranged from 68 to 4000 ppm and
              58 to 5500 ppm in samples collected
              before  (October 1992) and after (April
              1993) the winter heating season, re-
              spectively. The sum of the concentra-
              tions of  PAH in the pathway  soil
              samples varied from 3.0  to 1200 ppm
              in samples collected before the heat-
              ing season (October 1992). The sum of
              the concentrations of PAH ranged from
              0.58 to 610 ppm and from 0.63 to 63
              ppm in pathway soil and foundation
              soil samples collected after the heat-
              ing season (April 1993),  respectively.
              The concentrations of most 4- to 6-ring
              PAH, the sum of all target PAH, and the
              sum of PAHs that are probable human
              carcinogens in house dust correlated
              well with  the corresponding levels in
entryway soil. However, there was no
correlation between the PAH concen-
trations in house dust and in pathway
soil, nor was any relationship  found
between house dust and foundation
soil.
  The  PCB concentrations in  house
dust, entryway soil, pathway soil, and
foundation soil were lower than the PAH
concentrations in these samples. The
sum of the concentrations of all target
PCB varied from  210 to 1900 ppb in
house  dust, from 30 to 880 ppb in
entryway soil, from 16 to 500 ppb in
pathway soil, and from 18 to 210 ppb
in foundation soil. Higher PCB concen-
trations were found in house dust
samples than in entryway soil samples.
Similar PCB concentrations were ob-
served in  pathway soil samples and
foundation  soil samples, which are
lower than the PCB found in entryway
soil samples. The concentrations of
penta-PCB, hexa-PCB, and the sum of
all target PCB in house dust correlated
well with corresponding levels in
entryway soil. However, this relation-
ship was not observed for the PCB
concentrations in house dust and path-
way soil, nor was there any discernible
relationship between the PCB concen-
trations in house dust and foundation
soil samples.
  This report is submitted in fulfillment
of Contract Number 68-DO-0007, Work
Assignment No. 35, Task 1, by Battelle
under the sponsorship of the U.S. En-
vironmental Protection Agency. This
report covers the period between June
1992 and September 1993. Work was
completed as of September 1993.
                                                           Printed on Recycled Paper

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  This Project Summary was developed
by EPA's Atmospheric Research and
Exposure Assessment Laboratory, Re-
search Triangle Park, NC, to announce
key findings of the research project that
Is fully documented In a separate report
of the same title (see Project Report
ordering Information at back).

Introduction
  Recant studies to develop suitable sam-
pling and monitoring techniques for estab-
lishing human exposure to pesticides have
suggested that  relatively high  levels of
pesticide residues may occur  in house
dust. Residues tracked into the home may
remain in carpets for prolonged  periods
due  to  the  absence of environmental
weathering effects. These  residues may
be picked up by the skin on contact. Once
on the skin, the pesticides may be ad-
sorbed directly or transferred to the mouth
and  ingested. Because young  children
spend a great deal  of time on the floor,
they are particularly susceptible  to expo-
sure to  these chemicals as a  result of
dermal contact with house dust and the
frequent  hand-to-mouth contact that ac-
companies their normal play activities. An
estimate of average daily  soil  and dust
ingestfon by young children ranges from
0.02 to 0.2 g, with a potential for up to 5 g
per day for children exhibiting pica behav-
ior who live  in  a dusty home  or  have
access to exposed soil.
  PAHs and PCBs  represent two impor-
tant groups of semivolatile organic com-
pounds  (SVOCs) that have been found in
indoor and ambient air. Many PAHs are
known to be carcinogens or mutagens,
and  adverse health effects have been
linked to exposure to PAH. The presence
of environmental tobacco smoke has been
shown to be the most important indoor
source of PAH in air. Other indoor activi-
ties that may contribute to PAH concen-
trations  in indoor air are grilling of foods,
the use  of gas cooking and heating appli-
ances, the use of fireplaces or woodstoves,
the use of unvented kerosene space heat-
ers,  and the intrusion of contaminated
ambient air. The levels of PCB in indoor
air have been found to be higher than in
outdoor  air in several studies.  Defective
fluorescent light ballasts are suggested as
one important indoor PCB source.
  Higher PAH levels have been found in
dust or  soil  samples taken  near heavy
traffic. Therefore, homes located down-
wind of  heavy  traffic may have higher
PAH levels in house dust than  those in
lighter traffic areas. Very little information
Is available, however,  about the occur-
rence and distribution of PAH and PCB in
house dust resulting from indoor sources
or from track-in of outdoor dislodgeable
soil residues. Data also suggest a pos-
sible magnification of lead (Pb) in soil
near foundations. If  such magnification
near the foundation occurs, it may be due
to the  deposition  of  atmospheric Pb on
the roof and the outside surfaces of the
house, which then falls or washes down
to the soil near the drip line of the roof. It
is not  clear whether such magnification
also occurs with  SVOCs,  such as  PAH
and PCB.

Objectives
  There  are  no  established  monitoring
methods for PAH  and PCB in house dust
and track-in soil. Therefore, this study was
undertaken to evaluate monitoring meth-
ods for PAH and PCB in dust and soil
samples. The  specific objectives of the
study were
  1)  to evaluate and validate analytical
      methods  for measuring  PAH and
      PCB in dust and soil samples;
  2)  to obtain concentration  profiles for
      PAH and  PCB in dust  and soil
      samples from  an eight-home pilot
      field study conducted in Columbus,
      Ohio, before and after the 1992-
      1993 heating season;
  3)  to determine  whether  track-in of
      outdoor soil residues is  an impor-
      tant  source of PAH and  PCB in
      house dust; and
  4)  to determine whether magnification
      of PAH and PCB levels occurs in
      the foundation  soil.
This study was carried out in two phases
to accomplish the  above objectives:
      Phase I—Validate analytical meth-
      ods for determining PAH and PCB
      in house dust and soil samples;
  •   Phase II—Conduct  a small-scale
      pilot field study.

Procedures
  Two extraction methods, Soxhlet extrac-
tion and sonication, were evaluated and
validated for removing PAH and/or PCB
from dust and soil sample matrices. The
analytical method  validated for determin-
ing PAH in house dust and soil samples
consists of sonical extraction of the sample
with C6 and GC/MS analysis. The  vali-
dated analytical method for  determining
PCB in dust and soil  samples consists of
   1)  sonical extraction of the sample with
      10 percent  ether in C6)
  2)  silica gel fractionation of the sample
      extract, and
  3)  GC/MS analysis of the target frac-
      tion.
  A small-scale pilot field study was con-
ducted before and after the  1992-1993
heating season by collecting and analyz-
ing house  dust  and soil samples from
eight homes. The first sampling session
took place in June 1992 when only house
dust samples were collected. The second
sampling session occurred in  October
1992. At each home, house dust, entry way
dirt, and pathway soil samples were col-
lected. During the third sampling session
in April 1993, house dust, entryway dirt,
pathway soil, and foundation soil samples
were collected from each home. The dust
and soil samples were  prepared by the
methods validated for PAH and PCB analy-
sis.

Results
  Quantitative recoveries (> 80  percent)
of the spiked perdeuterated  PAH  were
obtained  when either  DCM or  C? were
used as  the extraction  solvent  with the
Soxhlet technique. Both  DCM and C6  ef-
fectively remove PAH from  the dust and
soil samples,  but the  silica gel cleanup
step is  not required when Ce  is used.
Therefore C6 was used as the extracting
solvent in the experiments to evaluate dif-
ferent sonication conditions. Quantitative
recoveries  were obtained  when  the
samples were sonicated  twice with C6  for
30 minutes. The recoveries  in this experi-
ment  ranged  from  91  percent for
fluorene-d10 to 100 percent for pyrene-d,0.
This sonication condition was used with
the spiked  soil samples, and recoveries
ranged from  91  percent (fluorene-d,0) to
98 percent (benzo(k)fluoranthene-d,2). The
precision for measuring native PAH in trip-
licate samples was within 15 percent (rela-
tive standard deviation) with this sonication
method. In summary, the analytical method
adopted consists of extracting the sample
twice by sonication with  10  mL of C6 and
analyzing the concentrated  C6 extract by
GC/MS to determine the target PAH. The
two 30-minute sonications  with  C6 offer
the best recoveries for perdeuterated PAH
in spiked dust and soil samples but not for
spiked 13C-labeled PCB. Approximately 50
percent of  each spiked  13C-labeled PCB
was recovered using this method. Experi-
ments were then carried  out using a more
polar solvent, 10 percent ether  in C6. In
summary, the analytical method used con-
sists of extracting the samples  twice  by
sonication with 10 mL of 10 percent ether
in C6 for 10 minutes, fractionating the ex-
tract on a silica gel column, and analyzing
the target fraction by GC/MS.
   In the pilot field study, the average PAH
concentrations in house dust samples were
less than 1  ppm for most 2-  to 3-ring PAH

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  and greater than 10 ppm for most 4- to
  6-ring PAH. Among the measured target
  PAH,  the most  abundant  PAHs found in
  these house dust  samples were 4-ring
  (fluoranthene  and pyrene)  and  5-ring
  (benzofluoranthenes and benzo(a)pyrene)
  PAH.  The least abundant PAHs found in
  these samples were, in general, the vola-
  tile 2-ring PAH and the reactive PAH such
  as  acenaphthylene  and cyclopenta-
  (c.d)pyrene. Note that naphthalene con-
  centrations  were less  than  1  ppm from
  samples collected in June 1992 and April
  1993, but the concentrations were greater
  than  1 ppm from  samples collected in
  October 1992. The  low concentrations of
  acenaphthylene and cyclopenta(c,d)pyrene
  in  house  dust samples are partly due to
  the reactivities of these compounds. As
  demonstrated  in  previous  studies,
  acenaphthylene and cyclopenta(c,d)pyrene
  can oxidize to  naphthalene dicarbonylic
•  acid anhydrides and pyrene dicarbonylic
  acid anhydrides, respectively. The  highest
  PAH concentrations in dust were found in
  samples  collected  from  a nonsmoker's
  house (H08) for all three sampling  events.
  In this house, similar PAH concentrations
  were obtained from house dust samples
  collected before the heating season (June
  1992 and October 1992). Relatively lower
  PAH concentrations were observed in the
  house dust sample collected after the heat-
  ing season  (April 1993).  The concentra-
  tions  of  the well  known carcinogen,
  benzo(a)pyrene (BaP) in this house were
  54, 44, and 24 ppm in house dust samples
  collected during June 1992, October 1992,
  and April 1993,  respectively.  The  PAH
  concentrations in dust  samples  collected
  from the smokers' houses (HOI, H04, H05,
  and H06) were  not always  higher than
  those from the nonsmokers' houses. This
  finding suggests that the presence of en-
  vironmental  tobacco smoke (ETS)  is not
  the only source  for PAH in house dust.
  The sum of the concentrations of the seven
  B-2 PAH  (probable human  carcinogen)
  were 10 to 300 ppm in the dust samples
  collected before the heating season (June
  1992 and  October 1992) and 13 to 160
  ppm in the samples collected after  the
  heating season (April 1993). These levels
  are well above the  1 ppm level that  the
  Washington  State Model Toxics Control
  Act sets as  standard for the B-2 PAH for
  residential soil at hazardous waste sites.
  Note that the sum of the concentrations of
  B-2  PAH  are approximately half  of the
  total concentrations of all 19 target PAHs
  (2-  to 6-ring) in all but  four samples col-
  lected during the three sampling sessions.
   The most abundant and least abundant
 PAH in entryway soil are similar to those
 found in house dust. The concentrations
 of target PAH were higher in entryway soil
 in samples  compared  to  house  dust
 samples. The PAH concentrations found
 in entryway soil in samples collected be-
 fore  the heating season  are  within the
 same order of magnitude as levels in the
 samples collected after the heating sea-
 son.  The highest PAH concentrations in
 entryway soil samples were from  House
 H08, which also showed the highest PAH
 concentrations in house dust samples. The
 BaP  concentrations in  entryway samples
 from  House H08 were  350 and 380 ppm
 before  and  after the heating season,
 respectively. The sum of the concen-
 trations for B-2 PAH were also about half
 of the sum of the concentrations for all 19
 PAHs in most entryway soil samples. We
 also investigated the relationship between
 the  measured PAH  concentrations  in
 house dust and entryway soil samples to
 determine whether any correlation exists
 between the PAH levels in these samples.
 A linear regression analysis was performed
 on each measured target PAH to deter-
 mine the correlation coefficient (R2). Stron-
 ger relationships were  observed for B-2
 PAH  (probable human carcinogens), other
 nonvolatile 4- to 6-ring PAHs, and the
 sum of all PAHs. As expected, the volatile
 PAH  and reactive PAH showed weaker
 relationships. These results suggest that
 the effect of track-in from the door  mat is
 an important source of PAH in house dust.
   The PAH concentrations found in path-
 way  soil samples  were  lower than the
 levels in house  dust  and entryway soil
 samples. The least and  most abundant
 PAH found in pathway soil samples were
 similar to house dust and entryway soil
 samples. Higher PAH concentrations were
 found in pathway soil samples collected
 before the heating season (October 1992)
 compared to those collected after the heat-
 ing season (April 1993) for  all but one
 household. The  average concentrations
 from  the eight  houses sampled ranged
 from 0.059 ppm of naphthalene to 36 ppm
 of pyrene before the heating season, and
 from 0.023 ppm of naphthalene to 16 ppm
 of fluoranthene after the heating season.
 The fact the House H08 showed the high-
 est PAH concentrations in entryway soil
 and house dust samples may have been
 caused  by the pathway soil  samples in
this house having been taken along the
driveway, the major walkway of the house.
The homeowner paved  the driveway ap-
 proximately 2 weeks before the October
 1992 sampling session.
   The average PAH concentrations in the
 foundation soil samples ranged from 0.023
 ppm of  naphthalene  to  3.3 ppm  of
 fluoranthene. Levels of PAH found in the
 foundation soil samples were lower than
 the levels in the pathway samples for all
 but one house (H05). The  PAH concen-
 trations in the foundation soil from House
 H08 were not one of the highest levels of
 all the foundation soil samples. This can
 be partly expjained  by the fact that the
 foundation soil sample from House H08
 was taken from the driveway. The sources
 of the extremely high levels of PAH in
 house dust, entryway soil,  and pathway
 soil from this house  (H08) are not under-
 stood clearly yet. In general, the relative
 concentration trend for target PAH  is
 entryway  soil > house dust > pathway >
 foundation soil.
   The most abundant PCB found in house
 dust entryway soil, pathway soil, and foun-
 dation soil samples  are. penta-PCB, and
 the  least  abundant  PCB was the most
 volatile mono-PCB. None of the nona-PCB
 and deca-PCB  were found  in  these
 samples. The concentrations of penta-PCB
 ranged from 71 to 950 ppb in house dust
 samples, from 10 to  520 ppb in  entryway
 soil samples, from 4.6 to 280 ppb in path-
 way soil samples, and from 7.5 to 87 ppb
 in foundation soil samples. The highest
 PCB concentrations  in the house dust,
 entryway  soil,  pathway soil, and founda-
 tion soil  samples are from House H03.
 Unlike PAH, the highest PCB concentra-
 tions were found  in house dust samples
 followed by entryway soil samples. Simi-
 lar PCB concentrations were found in path-
 way soil and foundation soil samples. We
 conducted a linear regression analysis on
 the measured PCB  concentrations from
 house  dust and entryway  soil samples.
 The  concentrations  'of  penta-PCB,
 hexa-PCB, and total PCB  show  strong
 correlations between  house dust samples
 and entryway soil samples. Weaker rela-
 tionships were observed for mono-, di-,
 tri-,  and  tetra-PCB, which  are  probably
 due to the low concentrations  for these
 PCBs in most of the samples. There is no
 correlation  between the PCB concentra-
 tions in house dust and pathway soil, nor
 can any significant relation be established
 between house dust  and foundation soil
 samples. This  is probably due to differ-
 ences in environmental weathering effects
between pathway  and foundation soil on
the one hand and between entryway soil
and house dust on the other.

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Conclusions and
Recommendations

  An  analytical  method  consisting of
sonlcal extraction of the sample with C6
and GO/MS analysis  was validated for
determining PAH in house dust and soil
samples. With this method, the spiked
PAHs were quantitatively recovered from
dust and  soil  samples. The recoveries
ranged  from 91  (fluorene-d10) to  100
(pyrene-d10) percent in the dust samples
and from  91  (fluorene-d,0)  to  98
(banzo(k)fluoranthene-d12) percent  in the
soil samples.
  An  analytical method for  determining
PCB in the  dust and soil samples  was
validated. This method consists of
  1)  sonical extraction of the sample with
      10 percent ether in C6,
  2)  silica gel fractionation of the sample
      extract, and
  3)  GO/MS analysis of the target frac-
      tion.
The recoveries of spiked 13C-labeled  PCB
ranged from 91 (4-chlorobiphenyl (13C6)) to
99  percent  (3,3',4,4'-tetrachlorobiphenyl
(13C«)) in the dust samples and from 90
(2,2', S.S'.S.S'.e.e'-octachlorobiphenyl (13C12))
to 93  percent (3,3',4,4'-tetrachlorobiphenyl
("0,2)) In the soil samples.
  The sum of the target PAH concentra-
tions in house dust ranged from 16 to 580
jig/g (ppm) in samples collected before
the 1992-1993 heating season and  from
25 to 310 ppm in samples collected  after
the heating season. PAH concentrations
were higher in entryway soil samples than
in the corresponding house dust samples.
The sum of  PAH  concentrations in
entryway soil samples ranged from  66 to
4000 ppm and 58 to 5500 ppm in samples
collected before and after the heating sea-
son, respectively. The sum of  PAH  con-
centrations ranged from 3.0 to  1200 ppm
and 0.58  to  610  ppm  in pathway soil
samples collected before  and after the
heating season, respectively. The sum of
PAH  concentrations in foundation  soil
samples collected after the heating sea-
son ranged from 0.63 to 63 ppm.
  The concentrations of those PAHs that
are probable human carcinogens (desig-
nated as. B-2 PAH) account for  roughly
half of the concentrations of the sum of all
target PAHs in  most dust  and soil sam-
ples. With few exceptions, the general con-
centration trend for the PAH in the house
dust samples was entryway soil > house
dust > pathway soil > foundation soil. The
concentrations of  the 4- to 6-ring PAH,
B-2 PAH, and the sum of all target PAH in
entryway soil samples correlate well with
the corresponding  levels in house dust
samples. However, there is no correlation
between the PAH concentrations in house
dust and in pathway soil  samples. Nor
does any relation exist between the PAH
concentrations in house dust and  in foun-
dation soil  samples. This  absence of a
relationship is probably due to differences
in environmental  weathering  effects on
pathway  and foundation soils compared
with the effects  on  house dust  and
entryway soils. The effect of track-in could
be a significant factor contributing to PAH
levels in house dust,  and more  studies
are needed to investigate this factor. The
presence of environmental tobacco smoke
is not the only important source of PAH in
house dust. Furthermore, there is no evi-
dence that PAH magnification occurs  in
foundation soil samples.
  The sum of the target PCB concentra-
tions in house  dust samples varied be-
tween 210  and 1900 ng/g (ppb)  and,  in
entryway soil samples, ranged from 30 to
880 ppb. The sum of the PCB concentra-
tions ranged from 16 to  500 ppb and from
18 to 210 ppb in pathway soil and  founda-
tion soil samples,  respectively. All these
samples were collected during April 1993.
The PCB concentrations are  lower than
the PAH concentrations in all house dust,
entryway soil,  pathway soil and  founda-
tion soil samples. Unlike PAH, the general
concentration trend for PCB was  house
dust > entryway soil > pathway soil. Simi-
lar PCB concentrations were found in path-
way soil and foundation soil samples. As
in the case of the PAH, there is no evi-
dence of PCB magnification occurring in
foundation soil.  The concentrations of
penta-PCB,  hexa-PCB,  and total PCB
house  dust samples correlate  well with
those in entryway samples. However, there
is no significant correlation for mono-, di-,
tri-, and tetra-PCB concentrations in house
dust and entryway soil samples, which is
probably due to the low concentrations of
these PCB compounds. There is also no
correlation between the sum of the PCB
concentrations in house dust and path-
way soil samples.  Furthermore, there is
no relationship between the PCB concen-
trations in house dust and in foundation
soil.
  There are several important issues that
remain to be addressed  in order  to as-
sess exposure due  to house  dust  and
soil. In future studies, we recommend
  1)  Measuring the PAH in house dust,
      entryway  soil, pathway  soil  and
      foundation soil in a sufficiently large
      sample  of homes  located  in the
      same community as House H08 in
      this study, in  order to investigate
      whether the high  PAH concentra-
      tions observed in the house dust
      and soil at this house are also found
      in these samples.
  2)  Conducting a similar study in a city
      in a colder climate with a history of
      coal burning.
  3)  Conducting a similar study in a city
      in a mountain  valley with  a  history
      of wood burning.
  4)  Conducting a similar study in a city
      with heavy traffic.
  5)  Determining the effect of track-in
      and dust control techniques  on ex-
      posure to  PAH in house dust.

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