with time since the chloralkali plant was closed. The chronology of mercury deposition in the impoundment inferred ~ profiles in the cores suggested that mercury from 1 3 T Cactivity input to the impoundment was highest during early operations of the upstream chloralkali plant and perhaps again near the end of operations. Overall results of this study substantiated that recovery of a river-reservoir system formerly subjected to high discharges of mercury by a chloralkali plant has been very slow and is far from complete. Continued losses of mercury from mercurycontaminated solid wastes stored at the plant site are implicated in this slow recovery. Acknowledgment
J. R. Lund provided analytical support; D. Klein and S.E. Herbes critically reviewed the manuscript. Literature (1) Nakanishi, J., “The Cause and Channels of Mercury Pollution in Western Ontario”, Appendix I in: Buffa, L., Report E P S 3WP-76-7, pp 43-52, Environment Canada, 1976. ( 2 ) Armstrong, F.A.J., Hamilton, A. L., in “Trace Metals and Metal-Organic Interactions”, P . C. Sinaer, Ed.. DU 131-55. 1974. (3) Annett,C. S.,D’Itri, F. M., Ford, J. R.;Prince, H. H., J Enciron Qual., 4, 219-22 (1975). (4) Bailev. D. S..“The Occurrence of Mercurv in the Fish and Sediment the North Fork of the Holston Rive; 1970-1972”, Va. State Water Control Bd., Basic Data Bull. 41,62 pp, 1974. (5) Hildebrand, S. C., Andren, A. W., Huckabee, J . W., in: “Toxicity to Biota of Metal Forms in Natural Waters”, Proc. of Int. ,Joint Commission on Great Lakes Research, R. W. Andrew, P. V. Hodson, and D. E. Konasewich, Eds., pp 211-32, Duluth, Minn., 1976. (6) Toole, T . W., Ruane, R. J., “Evaluation of the Mercury Monitoring Program-The North Fork Holston River”, Report EWQ-76-2, 33 pp, Tenn. Valley Authority, 1976. (7) Van Hook, R. I., Hildebrand, S.G., Huckabee. J. W.. Lindberg, S. E., Turner, R. R., Lund, J . R., “Biogeochemistry of Mercury in a River-Reservoir System: Impact of an Inactive Chloralkali Plant on the Holston River-Cherokee Lake”, ORNL/TM-6141, Oak Ridge National Lab, Oak Ridge, Tenn.. 1978. (8)U.S. Geol. Survey, CVater Resources Data for Virginia, 1975. (9) “Congressional Record”, Hearings on .‘Effects of Mercury on Man
OF
and the Environment”, Part 2 , July 29,30,1970, Serial No. 91-73, Appendix 3, pp 121-2,1970. (10) Hatch, W. R., Ott, W.L.,Anal. Chem., 40, 2085-7 (1968). (11) Feldman, C., ihid., 46, 1606-09 (1974). (12) Amer. Pub. Health Assoc., “Standard Methods for the Examination of Water and Wastewater”, 874 pp, APHA, Washington, D.C., 1971. (13) Thomas, R. L., Can. J . Earth Sci., 10,636-50 (1972). (14) Cranston, R. E., Buckley, D. E., Environ. Sei. Technol., 6,274-8 (1972). (15) Ritchie, J. C., McHenry, J. R., Gill, A. C., Limnol. Oceanogr., 18, 254-63 (1973). (16) Pennington, W., Cambray, R. S., Fisher, E. M., Nature, 242, 324-6 (1973). (17) Lindberg, S. E., Turner, R. R., ihid., 268,133-6 (1977). (18) Hem, J . D., U.S. Geological Survey Prof. Paper 713:19-24, 1970. (19) Hahne, H.C.H., Kroontje. W., Soil Sei. SOC.Am. Proc., 37, 838-43 (1973). ( 2 0 ) U.S. Dept. Interior, News Release, 6 pp, Sept. 16, 1970. (21) Lindberg. S.E., Andren, A. W., Harriss, R. C., “Geochemistry of Mercury in the Estuarine Environment”, in “Estuarine Research”, L. E. Cronin. Ed., Vol I, Academic Press, New York, N.Y., 1975. (221 deGroot. A. J . , deGoeij. J.J.M., Zegers, C.. Geol. Mijnhouu, 50, 393-8 (1971). (231 Hannan. P. J.. ThomDson. N. P.. J . Water Pollut. ControlFed.. 49,842-7 (1975). (24) O’Connor. D. J.. Water Resource., Res.. 12.279-94 (1976). (25) Shacklette, H. T.. Boerngen, .J. G., Turner, R; L., US.Geol. Surv. Circ. 644, 5 pp, 1971. (26) Lindberg, S. E.. Harriss, R. C.. Emiron. Sci. Technol., 8,459-62 (1974). (27) Anderson, A. A,, Grundforbattring, 28,95-105 (1967). ( 2 8 ) Kennedy, E. J., Ruch, R. R., Shimp, N. F., “Distribution of Mercury in Unconsolidated Sediments from Southern Lake Michigan”. Ill. State Geol. Survey. Environ. Geol. Note No. 44, 1971. (29) Robbins, J.A., Edgington. D. N.. Geochim. Cosmochim. Acta, 39, 285-304 (1953).
Receiced for recieic, ,Vocemher 16, 1977. Accepted February 2, 1978. Work supported b> the National Science Foundation-RAiVN Encironmental Aspects of Trace Contaminants Program under iVSF Interagenc) Agreement AELV-72-01243A03 with the Energy Research and Decelopmfnt Administration (noii,Department o/ E n ergy). Oak Ridge National Laboratory operated by I‘nion Carbide Corp. for the Department of Energy.
Characterization Techniques Applied to Indoor Dust Charles J. Weschler Bell Laboratories, Holmdel, N.J. 07733
Methods of characterizing dusts found within buildings were studied, using samples collected in Bell Laboratories’ facility a t Holmdel, N.J. Particle size and morphology were determined by optical and scanning electron microscopy. Quantitative analyses of C, H, and N were obtained, and semiquantitative analyses of elements with atomic numbers greater than 10 were carried out by energy-dispersive x-ray spectroscopy. Water soluble chloride, sulfate, nitrate, sodium, potassium, and calcium were determined using specific ion electrodes and energy-dispersive x-ray spectroscopy. The specific conductances of water extracts were measured. The principal elements present in the benzene soluble components were identified, and the organic functional groupings of these materials were examined by infrared spectroscopy.
0013-936X/78/0912-0923$01 .OO/O
@ 1978 American Chemical Society
Characterization of indoor dust should ultimately lead to a clearer understanding of the methods required to protect people and equipment against the problems caused by these particulates. However, there is little published information on the nature of indoor dust ( I ) . The chief purpose of the present study has been to explore means of characterizing indoor particulates. For convenience, the dust for trial characterizations was collected at Bell Laboratories’ facility at Holmdel, N.J. This building has a central air handling system with 85% NBS type filters; about 10%makeup outside air is added to the recirculated air. Experimental
Equipment. For microscopy with both transmitted and incident light, “reversed” binocular research microscopes were employed. Scanning electron microscopy was performed with
Volume 12, Number 8, August 1978 923
an AMR Model 1000 SEM equipped with an energy-dispersive x-ray spectrometer (lithium-drifted-silicon solid state radiation detector) and a computer-based analyzer. For x-ray analysis, the scanning electron microscope was routinely operated in secondary mode a t a potential of 30 kV, a beam amps, a beam diameter of C1> Si, Fe > S > K > Na. Al, P, and Zn were present, but to a lesser extent. Figure 1 compares the nearly identical x-ray spectra of dust collected from three different locations in the building. Quantitative analyses for C, H, and N are given in Table I, which shows that the analytical results for dusts from different sampling sites are very similar. Quantitative analyses of the Na, Si, S, C1, K, Ca, and Fe contents of a number of selected samples compare favorably with the semiquantitative x-ray data, as shown in Table 11, which lists the average weight percentages of the principal elements present. The dust’s water soluble ionic components, because of their possible corrosive effects, are perhaps of even greater interest than the elements which constitute it. The amounts of these components are reflected by the specific conductance of the water extracts listed in Table 111. The tabulated values are actually the specific conductance divided by the concentration expressed as parts of dust extracted per million parts of water (by weight). The specific conductances for samples from dif-
ferent sites are very similar. For comparison Table I11 includes equivalent conductance values, converted to parts per million, for a number of common electrolytes (8).Inspection of Table I11 indicates that roughly &11%of the dust, by weight, is water soluble ionic material. The concentrations of selected inorganic ions that contribute to this ionic material were determined by a variety of techniques. The amounts of fluoride, chloride, nitrate, and sulfate ions in the water extract were measured using specific ion electrodes; their weight percentages are listed in Table IV. Also included in Table IV are weight percentages of the water soluble sodium, potassium, and calcium ions present in the dust. These are approximate values, determined by energy dispersive x-ray techniques applied to both the dust samples and the water extracts. First, the x-ray spectra of the dust samples, before and after water extraction, were compared.
After washing with water, lines characteristic of Na and K were no longer detectable in the spectrum, and the intensities of S, C1, and Ca, relative to that of Si, were all reduced substantially (S 70%, C1 and Ca 50%). With the data in Table 11, these results provide a reasonable estimate of the concentrations. Then the principal inorganic elements in the water extracts themselves were determined by evaporating portions of the extracts to dryness on high-purity carbon studs. X-ray analyses of the residue salts indicated the presence of Ca > C1> S > Na K > P, consistent with the concentrations estimated above. Infrared spectra of these same residues included bands characteristic of sulfate (1200,1120,1085,650, and 595 cm-l) and carbonate (1400,870 cm-l). The presence of the carbonate salts was confirmed by a microchemical method (Le., bubbles of CO1 were evolved when a drop of 10% HC1 in glycerin was added to a sample of the dust).
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Table II. Elemental Composition of Holmdel Laboratory Dust
4
wt %
Elemont
H
5.3' 40.4' 3.2' 31-3ab 0.02' 0.92,a < l . O c K1.0'
