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Indoor air: Spatial variations of chlorinated pesticides
Atmospheric Printed
Ensironment
in Great
Vol. 23, No. 9. pp. 2063-2066,
WO&6981/89
1989. 0
Britain.
TECHNICAL INDOOR
AIR: SPATIAL VARIATIONS DAVID
1989 Pergamon
$3.OO+O.tY_7 Press plc
NOTE OF CHLORINATED
PESTICIDES
J. ANDERSON and RONALD A. HITES
School of Public and Environmental Affairs and Department of Chemistry, Indiana University, Bloomington, IN 47405, U.S.A. (First receioed 5 December 1988 and infinalform
21 February 1989)
Abetract-The concentrations of two classes of chlorinated pesticides were measured in various locations within four homes. The prevalent compounds were chlorinated derivatives of cyclopentadiene which had been used as termiticides. These compounds were found in basement areas at higher concentrations than in upstairs areas of the homes. Another class of chlorinated pesticide was represented by chlorpyrifos; its spatial profile was consistent with its application in upstairs areas. Key word index: Pesticides, indoor pollution.
INTRODUCLION Insecticides are used around the home for two main reasons: first, to prevent termites from consuming the wood out of which the house is constructed, and second, to prevent cockroaches ‘from making nuisances of themselves. In the first case, the ‘termiticide’ is applied around the soil-house interface. There are at least two ways of doing this. During construction, the termiticide can be sprayed into the void spaces of the concrete blocks that form the basement wall, or after construction, a termiticide can be injected into the ground around the outside of the house or sprayed into crawl spaces underneath the house. Insecticides used for cockroach control are usually sprayed around the dark comers of the upstairs areas, particularly under the kitchen cabinets. Previous work from our laboratory demonstrated that the termiticide, chlordane, was a common contaminant of indoor air, particularly in those homes where a route of migration from the outside soil was available (through cracks or holes in the foundation or basement wall) (Anderson and Hites, 1988).In one example, a home had high levels of chlordane in its basement as a result of such a migration pathway. In this home, the basement concentration was a factor of 13 higher than the upstairs concentration. On this basis, we formed a hypothesis that basement concentrations would exceed living area concentrations for those pesticides which were used for termite control but that living area concentrations would exceed basement concentrations for those pesticides used for cockroach control. This paper tests this hypothesis. EXPERIMENTAL Air samples were taken with polyurethane foam (PUF) plugs and DuPont P-4000A and SKC Aircheck VII constant-flow pumps following the method of Lewis and MacLeod (1982) and Lewis et nl. (1988). The PUF plugs (22 mm dia. x 8 cm)were pre-extracted with a 1: 1 mixture of acetone and hexane in Soxhlet extractors for 24-h and dried under vacuum. .The PUF plugs were kept in groups of three during pre-extraction and drying in order to provide two plugs for sampling and one blank. Duplicate samples were taken via a tee which was connected to the sampler inlet. Tbe sample volumes for an individual PUF plug were under 3 m3. The air flow was
assumed to be split equally between the two plugs, and the breakthrough of these compounds on PUF plugs was shown to be negligible for this volume. In fact, experiments which used two PUF plugs in series showed that breakthrough was negligible for these compounds at sample volumes up to 6 m3 per individual plug. Samples and blanks were returned to the laboratory within one hour of the end of the 24 h sampling period and stored at - 10°C. The DIUKS _ _ were Soxhlet extracted with a 1: 1mixture of acetone and hexane. The internal standard used for quantification (2,2’,3,4,4’,5,6,6’-octachlorobiphenyl) was spiked directly onto the sample and blank PUF plugs prior to extraction. (This polychlorinated biphenyl is not found in Aroclor mixtures.) Extracts were concentrated by rotary evaporation and eluted from a 5 mm x 8.5 cm column packed with alumina (lo?4 deactivated). The final sample volume was approximately 200 ~1. Chlorinated pesticides were analyzed by electron capture, negative ion, mass spectrometry (ECNIMS) on a Hewlett-Packard 5985B gas chromatographic mass spectrometer (CC/MS). Selected ion monitoring was used, and the quantification ion for each pesticide was the most abundant ion produced when the ECNIMS ion source was at a temperature of 100°C and a pressure of 0.4 torr of methane. The pesticides which we studied were all derivatives of hexachlorocyclopentadiene with the exception of chlorpyrifos (0,O-diethyl-0-3,5,6trichloro-2-pyridyl-phosphorothioate). The chlorinated cyclopentadienes which we measured were aldrin, u- and y-chlordane, dieldrin, heptachlor, heptachlor epoxide (not present in any of the four homes). and tmns-nonachlor. Standards of ah the pesticides were obtained from the U.S. EPA Pesticides and Industrial Chemicals Repository, Research Triangle Park, NC. A standard solution of all the pesticides and the internal standard was used to calculate response factors for quantification and to verify gas chromatographic retention times. All data are averages of the two replicate samples and are blank-corrected. Homes are identified by idenfication numbers to assure anonymity. RESULTS AND DlSCUSSION The concentrations of the various pesticides for homes 21, 34,64, and 67 are presented in Table 1. In addition, we have
2063
2064
Technical Note
calculated a downstairs-to-upstairs ratio (down/up) for each pesticide in each home. These values are the geometric average of the upstairs values divided into the basement values. (In home 34, we averaged the hallway and basement values to get basement concentrations.) The results for home 21 (see Table 1) show a down/up ratio of chlorpyrifos, a pesticide used for cockroach control, of 0.9; this indicates that this compound is used throughout the home. The results for home 21 also indicate that a termiticide has leaked into the home from the basement walls. The construction of this home was completed in November 1985. The termiticide was sprayed into the void spaces of the basement block walls; this was verified by the owner, who was present at the time of application of the termiticide. In this case, the homeowner had requested that chlordane not be used for treatment. It is both unfortunate and ironic that the commercial exterminator chose aldrin as a substitute for chlordane: aldrin is a more toxic chemical than chlordane (Worthing, 1987),and it is banned for use in the U.S. (Merck Index, 1983). As a result of this termiticide application, the aldrin concentrations in this home are very high. In fact, the basement level of aldrin (5000 ng mm3) was well above the 1000 ng me3 guideline proposed by the National Academy of Sciences (NAS, 1982). Another interesting aspect of home 21 is the presence of dieldrin. This compound is elevated by a factor of 3 in the basement (see Table 1). There are two possible sources of dieldrin in this home: (a) dieldrin was present as a constituent or contaminant in the original termiticide; (b) dieldrin has been produced by the oxidation of aldrin. The first explanation would be difficult to test, unless a sample of the original termiticide could be obtained. However, the second explanation can be tested by measuring the relative aldrin and dieldrin concentrations over time. We have sampled the indoor air in home 21 over a 9-month period. The logtransformed ratio of aldrin to dieldrin concentrations correlates with time in both the living room (r = -0.85) and the
basement (r= -0.99) for four samples over this 9-month period. This may indicate a transformation. The spatial protile of chlorinated pesticides in home 34 is also given in Table 1. The hallway and basement data show higher levels of y- and a-chlordane and trans-nonachlor than do the living room and kitchen (by a factor of about 3). This is a general trend for these compounds; basement concentrations are higher than concentrations in the living areas in all four homes (see Table 1). The heptachlor concentrations are also higher in the basements of most of the homes. Clearly, technical chlordane (which also contains heptachlor) is leaking into these homes. The elevated concentrations of these compounds are a result of volatilization following their application for termite control (Louis and Kisselbach, 1987). Vapor pressure plays a significant part in determining indoor air concentrations. Figure 1 shows electron capture detector gas chromatograms of a technical chlordane mix: ture and the indoor air of homes 64 and 67. There is clearly ai enrichment of the more volatile (early eluting) components in the indoor air. We should point out that chlordane has recently been banned for use as a residential termiticide (Anonymous, 1987). This action was motivated by concerns about the adverse health effects resulting from exposure to these compounds in indoor air. Home 64 was built in 1979, and presumably, it was treated for termites at the time of construction. The owner verified that this home had not been treated for pests since 6 months after construction. The most significant aspect of these data is the detection of chlordane components at concentrations of 2 to 17 ngm- 3 in the indoor air almost 10 years after treatment (see Table 1 and Fig. 1). Again, the basement levels of chlordane are higher than the rest of the home by a factor of about 3. Mixing throughout this home is apparent. For example, the heptachlor concentrations are all about the same even though the upstairs hall is two floors above the basement. As we have noted for other homes, chlorpyrifos is also more concentrated in the upstairs of this home.
Table 1. Concentrations (in ng m-3) of several pesticides in the indoor air of four homes in Bloomington, IN Heptachlor
Aldrin
Chlorpyrifos
y-Chlordane
a-Chlordane
trans-Nonachlor
Dieldrin
Home 21 Bedroom Kitchen Living room Basement Down/up
5.7 2.8 4.2 4.3 1.1
170 540 300 5000 17
1.4 0.6 2.2 1.1 0.9
2.9 1.8 2.2 5.0 2.2
1.8 1.2 1.4 3.9 2.7
1.2 0.6 0.8 2.3 2.8
8.2 5.8 13 28 3.3
Home 34 Living room Kitchen Hallway* Basement Down/up
33 32 74 73 2.3
ND ND ND ND
1 ND ND ND _
5.0 4.5 11 30 3.8
1.5 1.1 3.3 8.0 1.7
1.1 0.8 2.4 7.2 4.4
ND ND ND ND ._
2.8 2.6 4.0 1.5
ND ND ND
0.4 0.6 0.2 0.4
5.2 5.4 17 3.2
3.9 4.3 15 3.7
2.0 2.1 7.2 3.5
0.4 0.6 0.4 0.8
Home 64 Upstairs hall Living room Basement Down/up Home 67 Den Kitchen Living room Basement Down/up
34 60 66 110 2.1
*Connected directly to basement.
10 17 21 58 3.8
17 89 54 22 0.5
26 40 41 200 5.7
19 27 28 200 8.2
13 19 19 160 9.6
1.9 5.6 3.7 26 7.6
2065
Technical Note
Technical Chlordane
HOME
Std.
64
Basement
Fig. 1. Electron capture detector gas chromatograms of a technicalgrade chlordane standard (top) and indoor air samples from the basements of homes 64 (middle) and 67 (bottom). Attenuations are not the same. GC conditions: Hewlett-Packard 5890 fitted with a 0.25 mm x 30 m, DB-5, column with 0.25 pm film thickness; temperature program: 60°C for 5 min. a ramn of 15°C ner min to 150°C. a rams of 1°C per min to 200°C and a ramp of l?C per min to 280°C. The 1°C window is shown. The peak identifications are: 1. isomer-Zchlordene; 2. heptachlor; 3. y-chiordene; 4. b-chlordene; 5. y-chlordane; 6. a-chlordane; 7. trans-nonachlor; 8. cis-nonachlor; 9. compound K.
The owner of home 67 indicated that treatment for termites was relatively recent, in the fall of 1986. Sampling was done approximately 1 year after treatment, and these results are shown in Table 1. This home had relatively high basement concentrations of a- and y-chlordane and trans-nonachlor (see Fig. 1). These levels were three orders of magnitude higher than typical outdoor concentrations (Bidleman et a/., 1986) and a factor of 7 higher than upstairs concentrations. The treatment of this home was by sub-surface injection around the outside of the foundation. The source of RE
23:9-M
chlordane vapors in this home is similar to home 63 which we described previously (Anderson and Hites, 1988): the basement of home 67 had cracks in the walls and an open hole in the floor for the basement sump pump. Home 67, like home 21, had measurable concentrations of aldrin and dieldrin in its air. Although the aldrin levels are considerably lower (by a factor of about 30) in home 67, the dieldrinconcentrations are about the same as home 21. The concentrations of heptachlor in homes 67 and 34 were similar to each other and were about 15 times higher than homes 21
2066
Technical Note
and 64. Chlorpyrifos was present in home 67 at high levels, and like the other homes, its downstairs-to-upstairs ratio was
It seems quite clear that the two classes of pesticides considered here are behaving differently in these homes. The basement concentrations of the termiticides (chlordane and aldrin) are often a factor of 3-10 higher than in the living areas and 2-3 orders of magnitude higher than outdoor concentrations. This pattern is consistent with their use around the foundation of the house. The cockroach control agent (chlorpyrifos) shows just the opposite behavior. Its upstairs concentrations usually exceed its downstairs concentrations. Again, this is consistent with its usage in the living areas of the homes. The importance of these observations is obvious; the need to protect a home against pests must be balanced against the risks of adverse health effects to the occupants which may result from exposure to hazardous air pollutants.
REFERENCES
Anderson D. A. and Hites R. A. (1988) Chlorinated pesticides in indoor air. Enuir. Sci. Technol. 22, 717-720. Anonymous (1987) Enoir. Sci. Technol. 21, 1143. Bidleman T. F., Billings W. N. and Foreman W. T. (1986) Vapor-particle partitioning of semivolatile organic compounds: estimates from field collections. Enoir. Sci. Technol. 20, 1038-1043. Lewis R. G., Bond A. E., Johnson D. E. and Hsu J. P. (1988) Measurement of atmospheric concentrations of common household pesticides: a pilot study. Enuir. Monit. Assess. J. 10, 59-73. Lewis R. G. and MacLeod K. E. (1982) Portable sampler for pesticides and semivolatile industrial organic compounds in air. Analyt. Chem. 54, 310-315. Louis J. B. and Kisselbach K. C. Jr. (1987) Indoorair levels of chlordane and heptachlor following termiticide applications. Bull. enuir. contam. Toxicol. 39. 911-918. Merck Index (1983) Tenth edition, p. 220: National Research Council (1982) An Assessment of the Health Risks of Seven Pesticides Used for Termite Control.
Acknowledgements-We
thank Ilora Basu for technical assistance and the homeowners who volunteered for this study. This work was supported by the U.S. Department of Energy through Grant Number DE-FGO2-87ER60530.
National Academy Press, Washington, D.C. Worthing C. R. (editor) (1987) The Pesticide Manual, 8th edition. British Crop Protection Council, London, England.
Ensironment
in Great
Vol. 23, No. 9. pp. 2063-2066,
WO&6981/89
1989. 0
Britain.
TECHNICAL INDOOR
AIR: SPATIAL VARIATIONS DAVID
1989 Pergamon
$3.OO+O.tY_7 Press plc
NOTE OF CHLORINATED
PESTICIDES
J. ANDERSON and RONALD A. HITES
School of Public and Environmental Affairs and Department of Chemistry, Indiana University, Bloomington, IN 47405, U.S.A. (First receioed 5 December 1988 and infinalform
21 February 1989)
Abetract-The concentrations of two classes of chlorinated pesticides were measured in various locations within four homes. The prevalent compounds were chlorinated derivatives of cyclopentadiene which had been used as termiticides. These compounds were found in basement areas at higher concentrations than in upstairs areas of the homes. Another class of chlorinated pesticide was represented by chlorpyrifos; its spatial profile was consistent with its application in upstairs areas. Key word index: Pesticides, indoor pollution.
INTRODUCLION Insecticides are used around the home for two main reasons: first, to prevent termites from consuming the wood out of which the house is constructed, and second, to prevent cockroaches ‘from making nuisances of themselves. In the first case, the ‘termiticide’ is applied around the soil-house interface. There are at least two ways of doing this. During construction, the termiticide can be sprayed into the void spaces of the concrete blocks that form the basement wall, or after construction, a termiticide can be injected into the ground around the outside of the house or sprayed into crawl spaces underneath the house. Insecticides used for cockroach control are usually sprayed around the dark comers of the upstairs areas, particularly under the kitchen cabinets. Previous work from our laboratory demonstrated that the termiticide, chlordane, was a common contaminant of indoor air, particularly in those homes where a route of migration from the outside soil was available (through cracks or holes in the foundation or basement wall) (Anderson and Hites, 1988).In one example, a home had high levels of chlordane in its basement as a result of such a migration pathway. In this home, the basement concentration was a factor of 13 higher than the upstairs concentration. On this basis, we formed a hypothesis that basement concentrations would exceed living area concentrations for those pesticides which were used for termite control but that living area concentrations would exceed basement concentrations for those pesticides used for cockroach control. This paper tests this hypothesis. EXPERIMENTAL Air samples were taken with polyurethane foam (PUF) plugs and DuPont P-4000A and SKC Aircheck VII constant-flow pumps following the method of Lewis and MacLeod (1982) and Lewis et nl. (1988). The PUF plugs (22 mm dia. x 8 cm)were pre-extracted with a 1: 1 mixture of acetone and hexane in Soxhlet extractors for 24-h and dried under vacuum. .The PUF plugs were kept in groups of three during pre-extraction and drying in order to provide two plugs for sampling and one blank. Duplicate samples were taken via a tee which was connected to the sampler inlet. Tbe sample volumes for an individual PUF plug were under 3 m3. The air flow was
assumed to be split equally between the two plugs, and the breakthrough of these compounds on PUF plugs was shown to be negligible for this volume. In fact, experiments which used two PUF plugs in series showed that breakthrough was negligible for these compounds at sample volumes up to 6 m3 per individual plug. Samples and blanks were returned to the laboratory within one hour of the end of the 24 h sampling period and stored at - 10°C. The DIUKS _ _ were Soxhlet extracted with a 1: 1mixture of acetone and hexane. The internal standard used for quantification (2,2’,3,4,4’,5,6,6’-octachlorobiphenyl) was spiked directly onto the sample and blank PUF plugs prior to extraction. (This polychlorinated biphenyl is not found in Aroclor mixtures.) Extracts were concentrated by rotary evaporation and eluted from a 5 mm x 8.5 cm column packed with alumina (lo?4 deactivated). The final sample volume was approximately 200 ~1. Chlorinated pesticides were analyzed by electron capture, negative ion, mass spectrometry (ECNIMS) on a Hewlett-Packard 5985B gas chromatographic mass spectrometer (CC/MS). Selected ion monitoring was used, and the quantification ion for each pesticide was the most abundant ion produced when the ECNIMS ion source was at a temperature of 100°C and a pressure of 0.4 torr of methane. The pesticides which we studied were all derivatives of hexachlorocyclopentadiene with the exception of chlorpyrifos (0,O-diethyl-0-3,5,6trichloro-2-pyridyl-phosphorothioate). The chlorinated cyclopentadienes which we measured were aldrin, u- and y-chlordane, dieldrin, heptachlor, heptachlor epoxide (not present in any of the four homes). and tmns-nonachlor. Standards of ah the pesticides were obtained from the U.S. EPA Pesticides and Industrial Chemicals Repository, Research Triangle Park, NC. A standard solution of all the pesticides and the internal standard was used to calculate response factors for quantification and to verify gas chromatographic retention times. All data are averages of the two replicate samples and are blank-corrected. Homes are identified by idenfication numbers to assure anonymity. RESULTS AND DlSCUSSION The concentrations of the various pesticides for homes 21, 34,64, and 67 are presented in Table 1. In addition, we have
2063
2064
Technical Note
calculated a downstairs-to-upstairs ratio (down/up) for each pesticide in each home. These values are the geometric average of the upstairs values divided into the basement values. (In home 34, we averaged the hallway and basement values to get basement concentrations.) The results for home 21 (see Table 1) show a down/up ratio of chlorpyrifos, a pesticide used for cockroach control, of 0.9; this indicates that this compound is used throughout the home. The results for home 21 also indicate that a termiticide has leaked into the home from the basement walls. The construction of this home was completed in November 1985. The termiticide was sprayed into the void spaces of the basement block walls; this was verified by the owner, who was present at the time of application of the termiticide. In this case, the homeowner had requested that chlordane not be used for treatment. It is both unfortunate and ironic that the commercial exterminator chose aldrin as a substitute for chlordane: aldrin is a more toxic chemical than chlordane (Worthing, 1987),and it is banned for use in the U.S. (Merck Index, 1983). As a result of this termiticide application, the aldrin concentrations in this home are very high. In fact, the basement level of aldrin (5000 ng mm3) was well above the 1000 ng me3 guideline proposed by the National Academy of Sciences (NAS, 1982). Another interesting aspect of home 21 is the presence of dieldrin. This compound is elevated by a factor of 3 in the basement (see Table 1). There are two possible sources of dieldrin in this home: (a) dieldrin was present as a constituent or contaminant in the original termiticide; (b) dieldrin has been produced by the oxidation of aldrin. The first explanation would be difficult to test, unless a sample of the original termiticide could be obtained. However, the second explanation can be tested by measuring the relative aldrin and dieldrin concentrations over time. We have sampled the indoor air in home 21 over a 9-month period. The logtransformed ratio of aldrin to dieldrin concentrations correlates with time in both the living room (r = -0.85) and the
basement (r= -0.99) for four samples over this 9-month period. This may indicate a transformation. The spatial protile of chlorinated pesticides in home 34 is also given in Table 1. The hallway and basement data show higher levels of y- and a-chlordane and trans-nonachlor than do the living room and kitchen (by a factor of about 3). This is a general trend for these compounds; basement concentrations are higher than concentrations in the living areas in all four homes (see Table 1). The heptachlor concentrations are also higher in the basements of most of the homes. Clearly, technical chlordane (which also contains heptachlor) is leaking into these homes. The elevated concentrations of these compounds are a result of volatilization following their application for termite control (Louis and Kisselbach, 1987). Vapor pressure plays a significant part in determining indoor air concentrations. Figure 1 shows electron capture detector gas chromatograms of a technical chlordane mix: ture and the indoor air of homes 64 and 67. There is clearly ai enrichment of the more volatile (early eluting) components in the indoor air. We should point out that chlordane has recently been banned for use as a residential termiticide (Anonymous, 1987). This action was motivated by concerns about the adverse health effects resulting from exposure to these compounds in indoor air. Home 64 was built in 1979, and presumably, it was treated for termites at the time of construction. The owner verified that this home had not been treated for pests since 6 months after construction. The most significant aspect of these data is the detection of chlordane components at concentrations of 2 to 17 ngm- 3 in the indoor air almost 10 years after treatment (see Table 1 and Fig. 1). Again, the basement levels of chlordane are higher than the rest of the home by a factor of about 3. Mixing throughout this home is apparent. For example, the heptachlor concentrations are all about the same even though the upstairs hall is two floors above the basement. As we have noted for other homes, chlorpyrifos is also more concentrated in the upstairs of this home.
Table 1. Concentrations (in ng m-3) of several pesticides in the indoor air of four homes in Bloomington, IN Heptachlor
Aldrin
Chlorpyrifos
y-Chlordane
a-Chlordane
trans-Nonachlor
Dieldrin
Home 21 Bedroom Kitchen Living room Basement Down/up
5.7 2.8 4.2 4.3 1.1
170 540 300 5000 17
1.4 0.6 2.2 1.1 0.9
2.9 1.8 2.2 5.0 2.2
1.8 1.2 1.4 3.9 2.7
1.2 0.6 0.8 2.3 2.8
8.2 5.8 13 28 3.3
Home 34 Living room Kitchen Hallway* Basement Down/up
33 32 74 73 2.3
ND ND ND ND
1 ND ND ND _
5.0 4.5 11 30 3.8
1.5 1.1 3.3 8.0 1.7
1.1 0.8 2.4 7.2 4.4
ND ND ND ND ._
2.8 2.6 4.0 1.5
ND ND ND
0.4 0.6 0.2 0.4
5.2 5.4 17 3.2
3.9 4.3 15 3.7
2.0 2.1 7.2 3.5
0.4 0.6 0.4 0.8
Home 64 Upstairs hall Living room Basement Down/up Home 67 Den Kitchen Living room Basement Down/up
34 60 66 110 2.1
*Connected directly to basement.
10 17 21 58 3.8
17 89 54 22 0.5
26 40 41 200 5.7
19 27 28 200 8.2
13 19 19 160 9.6
1.9 5.6 3.7 26 7.6
2065
Technical Note
Technical Chlordane
HOME
Std.
64
Basement
Fig. 1. Electron capture detector gas chromatograms of a technicalgrade chlordane standard (top) and indoor air samples from the basements of homes 64 (middle) and 67 (bottom). Attenuations are not the same. GC conditions: Hewlett-Packard 5890 fitted with a 0.25 mm x 30 m, DB-5, column with 0.25 pm film thickness; temperature program: 60°C for 5 min. a ramn of 15°C ner min to 150°C. a rams of 1°C per min to 200°C and a ramp of l?C per min to 280°C. The 1°C window is shown. The peak identifications are: 1. isomer-Zchlordene; 2. heptachlor; 3. y-chiordene; 4. b-chlordene; 5. y-chlordane; 6. a-chlordane; 7. trans-nonachlor; 8. cis-nonachlor; 9. compound K.
The owner of home 67 indicated that treatment for termites was relatively recent, in the fall of 1986. Sampling was done approximately 1 year after treatment, and these results are shown in Table 1. This home had relatively high basement concentrations of a- and y-chlordane and trans-nonachlor (see Fig. 1). These levels were three orders of magnitude higher than typical outdoor concentrations (Bidleman et a/., 1986) and a factor of 7 higher than upstairs concentrations. The treatment of this home was by sub-surface injection around the outside of the foundation. The source of RE
23:9-M
chlordane vapors in this home is similar to home 63 which we described previously (Anderson and Hites, 1988): the basement of home 67 had cracks in the walls and an open hole in the floor for the basement sump pump. Home 67, like home 21, had measurable concentrations of aldrin and dieldrin in its air. Although the aldrin levels are considerably lower (by a factor of about 30) in home 67, the dieldrinconcentrations are about the same as home 21. The concentrations of heptachlor in homes 67 and 34 were similar to each other and were about 15 times higher than homes 21
2066
Technical Note
and 64. Chlorpyrifos was present in home 67 at high levels, and like the other homes, its downstairs-to-upstairs ratio was
It seems quite clear that the two classes of pesticides considered here are behaving differently in these homes. The basement concentrations of the termiticides (chlordane and aldrin) are often a factor of 3-10 higher than in the living areas and 2-3 orders of magnitude higher than outdoor concentrations. This pattern is consistent with their use around the foundation of the house. The cockroach control agent (chlorpyrifos) shows just the opposite behavior. Its upstairs concentrations usually exceed its downstairs concentrations. Again, this is consistent with its usage in the living areas of the homes. The importance of these observations is obvious; the need to protect a home against pests must be balanced against the risks of adverse health effects to the occupants which may result from exposure to hazardous air pollutants.
REFERENCES
Anderson D. A. and Hites R. A. (1988) Chlorinated pesticides in indoor air. Enuir. Sci. Technol. 22, 717-720. Anonymous (1987) Enoir. Sci. Technol. 21, 1143. Bidleman T. F., Billings W. N. and Foreman W. T. (1986) Vapor-particle partitioning of semivolatile organic compounds: estimates from field collections. Enoir. Sci. Technol. 20, 1038-1043. Lewis R. G., Bond A. E., Johnson D. E. and Hsu J. P. (1988) Measurement of atmospheric concentrations of common household pesticides: a pilot study. Enuir. Monit. Assess. J. 10, 59-73. Lewis R. G. and MacLeod K. E. (1982) Portable sampler for pesticides and semivolatile industrial organic compounds in air. Analyt. Chem. 54, 310-315. Louis J. B. and Kisselbach K. C. Jr. (1987) Indoorair levels of chlordane and heptachlor following termiticide applications. Bull. enuir. contam. Toxicol. 39. 911-918. Merck Index (1983) Tenth edition, p. 220: National Research Council (1982) An Assessment of the Health Risks of Seven Pesticides Used for Termite Control.
Acknowledgements-We
thank Ilora Basu for technical assistance and the homeowners who volunteered for this study. This work was supported by the U.S. Department of Energy through Grant Number DE-FGO2-87ER60530.
National Academy Press, Washington, D.C. Worthing C. R. (editor) (1987) The Pesticide Manual, 8th edition. British Crop Protection Council, London, England.