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(20) Bricard, J.; Billard, F.; Blanc, D.; Cabane, M.; Fontan, J. C. R. Seances Acad. Sci., Ser. B 1966,263, 761. (21) Nolan, P. J. Proc. R. Zr. Acad., Sect. A 1943, 49, 67. (22) Luhr, 0. Phys. Rev. 1930,2(35), 1394. (23) Glasstone, S.; Sesonske, A. Nuclear Reactor Engineering; Van Nostrand Reinhold: New York, 1967; p 30. (24) Miller, R. I. "Report No. SAI-79-503-ABQ";Science Applications: 1979. (25) Woo, S. B.; Helmy, E. M.; Mauk, P. H.; Paszek, A. P. Phys. Rev. A 1981, 24(3), 1380. (26) Barrow, G. M. Physical Chemistry, 3rd ed.; McGraw-Hill: New York, 1973; p 42. (27) Smith, I. W. M. Gas Kinetics and Energy Transfer; Ash-
(3) Wellisch, E. M. Philos. Mag. 1913, 26, 623. (4) Wrenn, M. E.; Spitz, H.; Cohen, N. IEEE Trans. Nucl. Sci. 1975, NS-22, 645. (5 ) Raes, F. Health Phys. 1985, 49(6), 1177. (6) Porstendorfer,J. 2. Phys. 1968, 213, 384. (7) Frey, G.; Hopke, P. K.; Stukel, J. J. Science (Washington, D.C.) 1981, 211, 480. (8) Raabe, 0. Nature (London) 1968, 21 7, 1143. (9) Townsend, J. S.; Dublin, M. A. Philos. Trans. R. SOC. London, A 1900, No. 193, 129. (10) Thomas, J. W.; LeClare, P. C. Health Phys. 1970,18, 113. (11) Porstendorfer, J.; Mercer, T. T. Health Phys. 1979,37,191. (12) Keefe, D.; Nolan, P. J. Proc. R. Ir. Acad., Sect. A 1962,62A, 43. (13) Busigin, C.; Busigin, A.; Phillips, C. R. In Radiation Hazards
more, Donovan, Eds.; The Chemical Society, Burlington House: London, 1977; Vol. 2. (28) Moelwyn-Hughes, E. A. Physical Chemistry, 2nd ed.; Pergamon: Oxford, 1961; Chapter 2. (29) Hawthorne, A. R.; Gammage, R. B.; Dudney, C. S.;Womack, D. R.; Morris, S. A.; Westley, R. R.; White, D. A. APCA Paper No. 83-9.10; Air Pollution Control Association: Pittsburgh, PA, 1983. (30) Spengler,J. D.; Duffy, C. P.; Letz, R.; Tibbitts, T. R.; Ferris, B. G., Jr. Environ. Sci. Technol. 1983, 17, 164.
in Mining: Control,Measurement and Medical Aspects; Gomez, M., Ed.; Kingsport Press: Kingsport, TN, 1981;
p 1043. (14) Goldstein, S. D.; Hopke, P. K. Environ. Sci. Technol. 1985, 19(2), 146. (15) Drzaic, P. S.; Marks, J.; Brauman, J. I. In Gas Phase Ion Chemistry;Bowers, M. T., Ed.; Academic: New York, 1984; Vol. 3, p 167. (16) Jordan, K. D.; Wendoloski, J. J. Chem. Phys. 1977,21,145. (17) Miguel, A. H.; Natusch, D. F. S.Anal. Chem. 1975,47,1705. (18) Chu, K.; Hopke, P. K. APCA Paper No. 85-85.5;Air Pollution Control Association: Pittsburgh, PA, 1985. (19) Chu, K. D. Ph.D. Thesis, University of Illinois, Urbana, IL, 1987.
Received for review June 15,1987, Accepted December 30, 1987. We thank the US.Department of Energy for their support of the project under ContractsDE AC02 83ER60186 and DE FG02 87ER60546.
NOTES Chlorinated Pesticides In Indoor Air David J. Anderson and Ronald A. Hites" School of Public and Environmental Affairs and Department of Chemistry, Indiana University, Bloomington, Indiana 47405
Indoor concentrations of chlorinated pesticides were measured in the air of 12 homes and found to be elevated with respect to typical outdoor concentrations. For example, indoor to outdoor concentration ratios for ychlordane were as high as 60 in the living area of one home and as high as 1000 in the basement of this home. Indoor sources for these chemicals are implied.
Introduction The average person spends about 90% of her or his time indoors (1). Thus, it is ironic that the setting of air quality standards for the protection of human health is based only on outdoor pollutant concentrations (1-5). Clearly, an evaluation of total human exposure to air pollutants should include effects of both outdoor and indoor air. For this reason, indoor air pollution has recently received a great deal of comment from both the mass media and the scientific community. From a scientific viewpoint, the emphasis has been on knowing the identities and concentrations of indoor air pollutants. The majority of the early research on indoor air dealt with the measurement of gaseous pollutants such as carbon monoxide (CO), nitrogen oxides (NO,), ozone (OJ, and sulfur oxides (SO,) (5). A chronological summary 0013-936X/88/0922-0717$01.50/0
of major U S . indoor air research reveals the neglect of organic pollutants in early indoor air research (5). There has been some research on volatile organic compounds (6-12), but there are few data on pesticides and related compounds (13-15). Our research focuses on the identification and quantification of semivolatile organic compounds (vapor pressures, 1mmHg) in the indoor air of single-family dwellings. This general category of indoor pollutants includes chlorinated pesticides. We measured the indoor concentrations of some of these compounds in the air of 12 homes and compared these concentrations to typical outdoor concentrations. Possible sources of these chemicals are proposed for some of the compounds.
Experimental Section Sampling. Homeowners were solicited by a news release that appeared in the local newspaper; 62 responses were received. Questionnaires .were used to select a subset of 12 homes for sampling. The questions requested general information about the size and age of the home and about possible sources of organic chemicals. The majority of the homes were located in the Bloomington, IN, area and were sampled during November of 1985 to October of 1986.
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Air samples were taken by using polyurethane foam (PUF) traps and constant flow pumps. PUF was selected to collect both vapor and particulate phases, which were subsequently extracted together. The PUF was obtained from Olympic Products Co. (Greensboro, NC) and was an open-cell, polyether type, with a density of 0.022 g/cm3. The PUF was cut into small plugs (22-mm diameter, 8-cm length), which were placed in glass sampling tubes under slight compression to prevent air seepage around the edges. Sampling was carried out in duplicate by means of a glass tee connected to the inlet of the pump. The sampling tubes were connected to the tee by 4-cm pieces of 6 mm i.d. Tygon tubing, and the tee was fitted into a 300-cm section of Teflon tubing for connection to the inlet of the pump. The pump exhaust was fitted with Tygon tubing, approximately 1.5 m in length, to reduce the possibility of sampling the exhausted air. The glass tubes and all other glassware used were acid-washed prior to use. This sampler design was based on the one described by Lewis and MacLeod (16). Two DuPont P-4000A constant-flow pumps (E. I. du Pont de Nemours & Co., Inc., Wilmington, DE) and two SKC Aircheck VI1 pumps (SKC Inc., Eighty Four, PA) were used for sampling. The pumps were calibrated with a large volume (approximately 1.3 L) soap bubble flowmeter. A nominal flow rate of 3 L/min and sample volumes of approximately 4 m3 were used. These flows were assumed to be split equally between the two plugs. Five flow-rate measurements before and after sampling were used for the calculation of air sample volumes. Both brands of pump contain servo mechanisms to maintain the flow rate at &5% of the set value during sampling. All flow rates in this work were within this tolerance. The replicate flow-rate measurements were all within 1 ?& relative standard deviation (RSD). The PUF plugs were preextracted prior to use. A 24-h Soxhlet extraction with acetone followed by 24 h with hexane was used. (Both solvents were glass-distilled grade.) The preextracted plugs were dried under vacuum at approximately 50 "C for 24 h. The PUF plugs were carried through the entire preextraction and drying steps in groups of three. This provided two plugs for replicate sampling and one field/procedure blank in each group. Samples and blanks were stored at -10 "C prior to Soxhlet extraction with a 1:l mixture of acetone and hexane. The internal standard (2,2',3,4,4',5,6,6'-octachlorobiphenyl) was spiked into the sample extracts after sample extraction and concentration. This polychlorinated biphenyl congener is not present in commercial Aroclor mixtures, and thus, it is not found in environmental samples. The extracts were concentrated by rotary evaporation and gentle blowdown under a stream of clean, dry nitrogen to a final volume of approximately 200 pL. Chlorinated Pesticide Analyses. All analyses were carried out on a Hewlett-Packard 5985B gas chromatographic mass spectrometer (GC/MS) by using electron capture, negative ion, mass spectrometry (ECNIMS) and operating at an ion source temperature of 100 "C and a pressure of 0.4 Torr. The gas chromatograph was fitted with a 30 m X 0.25 mm, DB-5, fused silica capillary column (J&W Scientific, Inc., Folsom, CA) with helium as the carrier gas. Selected ion monitoring (SIM) was used for quantification, and the most abundant ion produced for each compound, under the ECNIMS conditions described above, was used as the quantification ion; a confirmation ion for each compound was also monitored. The confirmation ions were selected from the same isotopic cluster as the quantification ions. 718
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30
-
25 r
,I C_:L
-
_oam,va- CHLORDAN E
S:P+G
-CHLORDANE
c,
c,
t-NONACHLOR
Figure 1. Concentrations of three components of technical-grade chlordane in the indoor air of homes. Concentrations are in nanograms per cubic meter; vertical scales are different. Horizontal axis numbers are home identification numbers. Samples from two outdoor locations in Bloomington, IN, are designated as outdoor. Our laboratory concentration is labeled lab. Homes that had doors and windows open during sampling are indicated by a circle around their number.
The chlorinated pesticides that were quantified were heptachlor, chlorpyrifos (also known as Dursban), y- and a-chlordane, and trans-nonachlor. Standards of these pesticides and the internal standard were obtained from the US. EPA Pesticides and Industrial Chemicals Repository, Research Triangle Park, NC. A standard solution was prepared, which contained all the pesticides and the internal standard, and this standard was used to calculate response factors used in quantification and to verify chromatographic retention times. Results and Discussion
Chlorinated Pesticides. The concentrations of ychlordane, a-chlordane, and trans-nonachlor in the various homes are given in Figure 1. All data are averages of duplicate samples. The data include indoor concentrations for 12 homes and outdoor concentrations at two locations in Bloomington. The results from a sample taken in our laboratory are also shown. The outdoor concentrations of these compounds are low. The average outdoor concentration of y-chlordane at the
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190
HEPTACHLOR
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Flgure 3. Concentrations of heptachlor In the indoor air of homes. Horizontal axis iabeis are the same as In Flgure 1.
Outdoor 10/30/88
Flgure 2. Concentrations of y-chlordane, a-chlordane, and trans nonachlor in the indoor and outdoor air of home 63.
140
two locations is 0.45 ng/m3. This is similar to the values reported by Bidleman et al. (17). The indoor concentrations for y-chlordane are much higher, ranging up to 29 ng/m3 and averaging 7.3 times higher than the outdoor air. Indoor-outdoor concentration ratios are useful for relating indoor and outdoor concentrations of pesticides because these chemicals can have both indoor and outdoor sources (5). Some of the homes were sampled with the doors and windows open (see Figure 1 caption). However, on the average, these homes have indoor concentrations similar to homes that were closed during sampling; t = 1.39. For example, home 12 was open and had a y-chlordane concentration of 17 ng/m3; this is only 40% less than the concentration found in home 63, which was closed during sampling. Both open and closed homes show substantially elevated concentrations relative to outdoor air. Clearly, these elevated indoor concentrations are not a simple function of reduced mixing of indoor and outdoor air. The three compounds seen in Figure 1 are all present in the commercial mixture known as technical-grade chlordane (18). We find that these three compounds covary with one another; the correlation coefficients are at least 0.98 for the three pairs of compounds. The most likely reason for this covariation is that these three compounds have the same ultimate source. Technical-grade chlordane contains approximately 24 % y-chlordane, 19% a-chlordane, and 7% trans-nonachlor (18). (Technical chlordane also contains approximately 7% of heptachlor, among other compounds.) The relatively high levels of chlordane in home 63 were investigated by using multiple indoor samples. The indoor to outdoor ratio in home 63 was 64 for y-chlordane. Replicate samples were taken simultaneously in the living area, outdoors, and in the basement. The results from this experiment are given in Figure 2. The concentrations in the living area for the two different dates are not statistically different, while the basement and living area samples of 10/30/86 are statistically different (95% confidence). The source of chlordane in home 63 is likely related to the elevated concentrations in the basement. This home was treated with chlordane in the late 1970'9, according to the resident, presumably by subsurface injection around the foundation of the house. It seems quite likely that chlordane has infiltrated through cracks in the basement walls. Indeed, large cracks in the basement walls were found upon inspection of this home. Similarly, home 12 was treated for termites in 1974. It is important to note that all of the indoor concentrations of chlordane are well below the 5000 ng/m3 guideline proposed by the National
140
..
B
ci
Figure 4. Concentrations of chlorpyrlfos in the Indoor air of homes. Horizontal axis labels are the same as In Figure 1.
Academy of Sciences (19). The data for heptachlor are shown in Figure 3. Heptachlor is also found in technical-grade chlordane, but it does not covary with the other three compounds discussed above (r < 0.4). Furthermore, the indoor concentrations of heptachlor are about a factor of 10 greater than the chlordanes. The source of heptachlor appears to be different from the other compounds, which are in technical-grade chlordane. Homes 61 and 62 were treated for termites in 1977 and 1984, respectively. The exact formulation of the termiticides that were used is uncertain, but there is a possibility that heptachlor was used. A commercial mixture of chlordane and heptachlor, known as Termide, is available (14). Heptachlor has a higher vapor pressure than y- and a-chlordane and trans-nonachlor (20);thus, it is possible that higher soil outgassing rates have contributed to the generally higher heptachlor concentrations. Chlorpyrifos is an organophosphorus pesticide (see Figure 4); it is used as a soil insecticide and for the control of household pests. The concentrations vary dramatically from home to home. These results can be interpreted according to information from the questionnaires. Owners of homes 60 and 62 both identified the use of chlorpyrifos on the questionnaire. The response from home 60 indicated spraying once every two weeks, by the homeowner, with a product containing chlorpyrifos. The spraying in home 62 was conducted by a professional service on a monthly basis. The only other homeowner to indicate the use of pesticides was the owner of home 12. In that case, sprayingfor termite protection in the basement crawl space and around the foundation was indicated. Conclusions These data indicate that the home application of pesticides (such as chlordane, heptachlor, and chlorpyrifos) leads to indoor concentrations of these chemicals that are Environ. Scl. Technol., Vol. 22, No. 6, 1988 719
higher than typical outdoor concentrations. Even applications of chlordane in locations exterior to a home can lead to elevated indoor concentrations if a pathway for migration into the home is available (such as a cracked foundation). Because of these high indoor concentrations, we suggest that regulations governing the use of pesticides in and around the home may warrant reevaluation.
Acknowledgments We thank Ilora Basu for technical assistance and the homeowners who volunteered for this study. Registry No. y-Chlordane, 5566-34-7; a-chlordane, 39765-80-5; trans-nonachlor, 39765-80-5; heptachlor, 76-44-8; chlorpyrifos, 2921-88-2.
Literature Cited Budiansky, S. Environ. Sci. Technol. 1980,14,1023-1027. Ott, W. R. Environ. Sci. Technol. 1985, 19, 880-886. Sexton, K.; Wesolowski, J. J. Environ. Sci. Technol. 1985, 19, 305-309. Spengler, J. D.; Sexton, K. Science (Washington,D.C.) 1983, 221, 9-17. Yocoin, J. E. J. Air Pollut. Control Assoc. 1982,32,500-520. Johansson, 1. Atmos. Environ. 1982, 8 , 1371-1377. Mdhave, L. Environ. Znt. 1982,8, 117-127. Miksch, R. R.; Hollowell, C. D.; Schmidt, H. E. Environ. Znt. 1982,8, 129-137. Berglund, B.; Johansson, I.; Lindvall, T. Environ. Znt. 1982, 8, 111-115.
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(10) Wallace, L.; Pellizzari, E.; Hartwell, T.; Rosenweig, M.; Erickson, M.; Sparacino, C.; Zelon, H. Enuiron. Res. 1984, 35, 293-319. (11) Hawthorne, A. R.; Gammage, R. B.; Dudney, C. S. Environ. Int. 1986, 12, 221-239. (12) Wallace, L. A.; Pellizzari, E. D.; Hartwell, T. D.; Whitmore, R.; Sparacino, C.; Zelon, H. Enuiron. Int. 1986,12,369-387. (13) Livingston, J. M.; Jones, C. R. Bull. Environ. Contam. Toxicol. 1981, 27, 406-411. (14) Wright, C. G.; Leidy, R. B. Bull. Enuiron. Contam. Toxicol. 1982,28,617-623. (15) Dobbs, A. J.; Williams, N. Environ. Pollut., Ser. B 1983, 6, 271-296. (16) Lewis, R. G.; MacLeod, K. E. Anal. Chem. 1982, 54, 310-3 15. (17) Bidleman, T. F.; Billings, W. N.; Foreman, W. T. Environ. Sci. Technol. 1986,20, 1038-1043. (18) Sovocool, G. W.; Lewis, R. G.; Harless, R. L.; Wilson, N. K.; Zehr, R. D. Anal. Chem. 1977,49,734-740. (19) Committee on Toxicology, National Research Council An Assessment of the Health Risks of Seven Pesticides Used for Termite Control;National Academy Press: Washington, DC, 1982. (20) Pesticide Manual, 4th ed.; Martin, H., Worthing, C. R., Eds.; British Crop Protection Council: London, England, 1974.
Received for review May 4, 1987. Revised manuscript received December 7,1987. Accepted January 27,1988. This work was supported by the U.S. Department of Energy through Grant 80- E VI 0449.
