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reconstructed chromatograms for the electron ionization and the negative chemical ionization mass spectra are shown in Figure 4. The ratios of the total ion current and the intensity for the molecule ion peak, which was virtually always the base peak in the spectrum, for the chlorinecontaining molecules whose chromatograms appear in Figure 2 and 4 are shown in Table 11. The variation between the results obtained for electron ionization and those for negative chemical ionization is expected on the basis of the very large differences in detector sensitivity for specific compounds in these two mass spectrometric techniques. The resulB illustrated in Table I1 suggest that an improvement in a decrease in the yield of chlorinated hydrocarbon emissions from thermal conversion of chlorinated polymers like poly(viny1idene chloride) of approximately 3 X lo2 is obtainable in an unoptimized fluidized-bed system. On the basis of the high exothermicity of CaC1, formation, it seems very likely to us that optimization of this technology will result in a significant increase in performance. Institution of the technological developments suggested above should result in a decrease in the exposure of the general population to chlorinated hydrocarbons. Registry No. Poly(viny1idene chloride), 9002-85-1; hexachlorobenzene, 118-74-1; pentachlorophenol, 87-86-5; 1,4-dichloroethenylbenzene, 51738-09-1; 2,4-dichloro-l-(2-chloroethenyl)benzene, 45892-47-5;1-chloronaphthalene,90-13-1;dichloronaphthalene, 28699-88-9; trichloronaphthalene, 1321-65-9; 2,2-dichloro-l,l'-biphenyl,13029-08-8;tetrachloronaphthalene, 1335-88-2;pentachloronaphthalene, 1321-64-8;trichloro-1,l'-biphenyl, 25323-68-6;9-(dichloromethylene)-SH-fluorene, 835-17-6; naphthacene, 92-24-0;benzo[c]phenanthrene,195-19-7;calcium oxide, 1305-78-8;chlorophenanthrene, 66214-77-5.
Literature Cited (1) Tondeur, Y.; Dougherty, R. C.; Rappe, C.; Buser, H. R. Abstracts; 27th Annual Meeting of the American Society
of Mass Spectrometry, Seattle, WA, 1979;American Society
of Mass Spectrometry: Seattle, WA, 1979; pp 419-420. (2) Bumb, R. R.; Crummett, W. B.; Cutie, S. S. Gledhill, J. R.;
Hummell, R. H.; Kagel, R. 0.;Lamparski, L. L. Louma, E. V.; Miller, D. L.; Nestrick, T. J.; Shadoff, L. A.; Woods, J. S. Science (Washington, D.C.) 1980,210,385-390. (3) VanDell, R. D.; Shadoff, L. A. Chemosphere 1984, 13, 672-775. (4) Crummett, W. B.; Townsend, D. T. Chemosphere 1984,13, 777-788. (5) Eiceman, G. A.; Clement, R. E.; Karasek, F. W. Anal. Chem. 1979,51,2342-2350. (6) Ballschimiter, K.; Kramer, W.; Nottrodt, A.; Sladek, K. D. Chemosphere 1984,13,1139-1143. (7) Oberg, T.; Aittola, J.-P.; Bergstrom, J. G. T. Chemosphere 1985,14,215-221. (8) Eiceman, G. A.; Rghei, H. 0. Chemosphere 1984, 13, 1025-1033. (9) Brocco, D.; Cavdaro, A.; Gorni, A.; Liberti, A. Chemosphere 1984,13,1319-1329. (10) Karasek, F. W.; Hutzinger, 0. Anal. Chem. 1986, 58, 633A-642A. (11) Dougherty, R. C.; Whitaker, M. J.; Tang, Sa-Y.;Bottcher, R.; Keller, M.; Kuehl, D. W. Environmental Health Chemistry; Ann Arbor Science: Ann Arbor, MI, 1980; Chapter 13. (12) Murature, D. A.; Tang, S.-Y.; Steinhardt, G.; Dougherty, R. C. Biomed. Environ. Mass Spectrom., in press. (13) Chem. Eng. News 1986,April 14,22. (14) Edelson, D.; Lum, R. M.; Reents, W. D., Jr. Symp. (Znt.) Combust., [Proc.] 1982, 19th, 807-814. (15) Collazo-Lopez, H.; Dougherty, R. C. Florida State University, unpublished results, 1985. (16) Ballistreri, A.; Foti, S.; Maravigna, P.; Montaudo, G.; Samporrino, E. J. Polym. Sei., Polym. Chem. Ed. 1980,18, 3101. (17) Benson, S. W. Chem. Rev. 1969,69,279. (18) Handbook of Chemistry and Physics, 66th ed.; Weast, R. C. Ed.; CRC: Boca Raton, FL, 1986. Received for review July 8, 1986. Revised manuscript received February 2, 1987. Accepted February 16, 1987.
Coating of Zooplankton with Calcium in Onondaga Lake, New Yorkt John E. Garofalo" Faculty of Chemistry, College of Environmental Science and Forestry, State University of New York, Syracuse, New York 13210
Steven W. Effler Upstate Freshwater Institute, Inc., Syracuse, New York 13214
The coating of zooplankton with calcium in hypereutrophic, polluted Onondaga Lake, NY, was documented by scanning electron microscopy and X-ray energy spectrometry. T h e epilimnion of the lake is continuously oversaturated with respect to the solubility of calcite. The coating phenomenon may have ecological implications.
Introduction Many hard-water lakes become oversaturated with respect to calcite during the warm and productive summer period (e.g., ref 1 and 2) because the solubility of calcite decreases with increases in temperature (3) and the photosynthetic depletion of CO, encourages greater oversaturation ( I ) . The level of primary productivity is probably 'Contribution No. 66 of the Upstate Freshwater Institute, Inc. 604
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the regulating effect in productive systems ( 2 , 4 ) . Precipitation of CaC03 is apparently a widely occurring phenomenon in hard-water lakes, as the sediments of these systems are generally rich in calcareous deposits (5). Documentation of the occurrence of carbonate precipitates in the water column of oversaturated lakes continues to increase (e.g., ref 1,2, and 4). The availability of surfaces (e.g., nucleation sites) probably affects the extent of oversaturation and rate of particulate calcium formation observed in a particular lake (2,4). Zooplankton represent a component of the particle surface area available for the precipitation of CaC03. Coating or encrustation of these surfaces may be important to the metabolism of affected organisms and the ecology of a lake by increasing the weight of individual 200plankton. We document here the coating of zooplankton in Onondaga Lake, NY, with calcium, on the basis of analyses with scanning electron microscopy (SEM) and
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X-ray energy spectrometry (XES). Onondaga Lake is a small (surface area of 11.7 km2, polluted mean depth of 12 m), dimictic, hypereutrophic lake located in metropolitan Syracuse, NY. The lake is rich in zooplankton (7).though the diversity is low. The lake receives ionic waste from an alkali manufacturer, rich in Ca2+,Na+, and CI-. Concentrations of Ca2* in the epilimnion of the lake are extremely high [=I4 mmol L-l (4)] as a result of the industrial discharge. The epilimnion of the lake is continuously oversaturated with respect to calcite (4) because of the elevated concentrations of Ca2+ and the high level of primary productivity. Oversaturation is greatest during the early-summer to midsummer phytoplankton bloom (4).
(a,
Materials and Methods Samples were collected approximately weekly for individual particle analysis from the epilimnion of the lake from early summer to late fall of 1985. The samples were stored in polyethylene containers for transport to the laboratoty (0.5 h). Several diquats (0.1-1.0 mL) of sample were filtered through Nuclepore polycarbonate membranes (0.4-fim pore size, 13-mm diameter) with a spot-sampling device. The filtrations were performed in a clean laminar flow hood. The membranes were transferred to carbon SEM stubs and attached with colloidal graphite in 2propanol. The specimens were coated with 2+30 nm of carbon in a high-vacuum evaporator. Specimens were examined on an ETEC Autoscan scanning electron microscope, operated at an accelerating voltage of 20 keV with a working distance of 15 mm (25 mm for X-ray analyses) and a specimen tilt angle of Oo. X-ray analyses were performed with a Kevex 5100c X-ray spectrometer system (X-ray spectra were collected by a raster scan over the center portion of each feature). On the basii of X-ray spectra, elemental maps for calcium were prepared for certain of the samples. Micrographs were recorded with Polaroid 55 P / N film. Analyses for Ca2+,alkalinity, and pH were performed (8)on samples collected weekly from several depths throughout the study period to keep apprised of attendant equilibrium conditions with regard to the solubility of calcite ( 4 ) . Results and Discussion Representative micrographs, X-ray spectra, and calcium X-ray maps are presented for two important forms of zooplankton from Onondaga Lake for the study period in Figures 1 and 2. Coleps sp. (Figure 1A) is a ciliated protozoan. The cladoceran in Figure 2A is a Ceriodaphnia sp. Ciliated protozoa are rarely observed in great numbers as plankton (9);however, Coleps sp. was the most abundant zooplankter from early July to midduly in Onondaga Lake (e.& 1 X 10s m-3 on July 3, 1985). Ceriodaphnia sp. was the dominant cladoceran during the sampling period; a t times it was present in concentrations greater than 1 x io5 m-3. The X-ray spectra (Figures 1B and 2B) indicate that both types of zooplankton were enriched with calcium; it was the dominant element detected in these cases. The other elements found to be apsociated with the zooplankton of the lake (P, S, CI)have been observed with biological particles elsewhere (10, 11). The elemental maps for calcium indicate Coleps sp. (Figure 1C) and Ceriodaphnia sp. (Figure 2C) were essentially completely covered (i.e., coated) with calcium, as the dimensions of the elemental maps are equivalent to the dimensions of the organisms. Note the presence of smaller particles rich in calcium (probably calcite) in the
Flgure 1. (A) Scanning electron micrograph of Coleps sp. from Onondaw Lake (400X). colbcted MI JuY 3. 1985. (6)X-ray specbum. (C) Calcium elemental map.
X-RAY ENERGY lKeVl
w
e 2. (A) Scanning electron micrograph of ceriodsphnla sp. from Onondaga Lake (130X). cdkcted on July 5. 1985. (6)X-ray specmm. (C) Calcium elemental map. elemental map for Coleps sp. The coating of zooplankton with calcium (probably as calcite) is presumably a manifestation of the highly oversaturated conditions that prevailed with respect to the solubility of calcite (Table I) in the upper waters of the lake. The mitigating chemical conditions (Table I) and the temporal and vertical distributions of calcite equilibrium conditions were similar to those systematically documented previously for the lake (4). The coating phenomenon may depress turnover rates and cause a greater expenditure of energy for locomotion as a result of the Environ. Scl. Technol.. Vol.
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Studies, SUNY-College of Environmental Science and Forestry, for their technical assistance and stimulating discussions and MaryGail Perkins for assistance in sample collection and drafting of X-ray spectra. We acknowledge Nancy Auer for enumeration of zooplankton. We also benefited from discussions with G. Russell-Hunter.
Table I. Ranges in Selected Chemical Conditions in the Upper 5 m of Onondaga Lake from Early Summer to Late Fall, 1985 condition PH [Ca2+],mrno1.L-’
range
7.3-8.0 11-15 1.2-2.2
alkalinity, mequiv-L-’ calcite saturation index (SI)” 0.3-1.1 ” SI = log [(ion activity product for calcite)/(thermodynamic solubility product for calcite)] ( 4 ) . SI > 0 corresponds to oversaturation.
greater weight of the zooplankton. The latter effect may have water-quality implications as it probably reduces grazing pressure on phytoplankton, and this may cause higher standing crops of phytoplankton and increased phytoplankton deposition. Effler et al. (12) hypothesized that the exceedingly high rates of oxygen depletion in the hypolimnion of Onondaga Lake are in part due to the high rate of phytoplankton deposition. The occurrence and extent of the calcium-coating phenomenon, documented here for Onondaga Lake, in other hard-water systems are unknown. The concentration of Ca2+in Onondaga Lake is unusually high as a result of the ionic waste received. However, the equilibrium conditions are not extraordinary with regard to the degree of oversaturation with respect to calcite solubility observed in other productive hard-water lakes (8). Thus, the coating phenomenon documented here may occur in other lakes that experience oversaturated conditions.
Acknowledgments We thank Robert Hanna, Arnold Day, and Jack McKeon of The N. C. Brown Center for Ultrastructure
Registry No. Calcite, 13397-26-7.
Literature Cited (1) Effler, S. W. J. Great Lakes Res. 1984, 10, 3-14. (2) Strong,A.; Eadie, B. J. Limnol. Oceanogr. 1978,23,877-887. (3) Stumm, W.; Morgan, J. J. Aquatic Chemistry;Wiley: New York, 1970. (4) Effler, S. W.; Driscoll, C. T. Environ. Sci. Technol. 1985, 19, 716-720. (5) Jones, B. F.; Bowser, C. J. Lakes: Chemistry, Geology,and Physics; Lerman, A. Ed; Springer-Verlag: New York, 1978; pp 197-235. (6) Effler, S. W.; Field, S. D.; Meyer, M. A.; Sze, P. J. Enuiron.
Eng. Diu. (Am. SOC.Ciu. Eng.) 1981, 107, 191-210. (7) Meyer, M. A,; Effler, S. W. Enuiron. Pollut., Ser. A 1980, 23, 131-152. (8) American Public Health Association Standard Methods for Analysis of Water and Wastewater, 14th ed.; American Public Health Association: Washington, DC, 1975. (9) Wetzel, R. Limnology; Saunders: Philadelphia, 1975. (10) Garofalo, J. E.; Johnson, D. L.; Hassett, J. M. In Trace Substances in Environmental Health, 18th; Hemphill, D. D., Ed.; University of Missouri: Columbia, MO, 1984, pp 403-415. (11) Mudrock, A. J. Great Lakes Res. 1984, 10, 286-298. (12) Effler, S. W.; Perkins, M. G.; Brooks, C. M. Water,Air, Soil Pollut. 1986, 29, 93-108. Received for review May 23,1986. Accepted December 24,1986.
CORRESPONDENCE Comment on “Regional Tree Growth Reductions due to Ambient Ozone: Evidence from Field Experiments” SIR Forests of the U.S.may well be adversely affected by ozone, but a case based on evidence for hybrid poplar cannot be made from the experiment of Wang et al. (I). The experiment that led the authors to conclude that ambient ozone causes regional tree growth reductions was confounded by a profound chamber effect as indicated by the significant improvement in growth in the ambient chamber vs. ambient no-chamber treatment. Even if there were no uncertainty in the methodology, 1 year of field data can never be considered definitive because of the yearly variability in growing conditions and in ozone episodes. In New Brunswick, NJ, we compared the growth of hybrid poplar “clone 388” in filtered and nonfiltered chambers for 5 years from 1975 to 1979 (2). No significant difference in linear growth was found between filtered and nonfiltered air treatments in any year or in biomass in the single year that it was measured, despite the occurrence 606
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of O3levels high enough to produce symptoms and growth reductions on sensitive herbaceous species. New Brunswick, NJ, is evidently a more polluted area than Millbrook, NY. Monitoring data for 1984 reveals 20 days in Millbrook compared to 46 in New Brunswick with a 1-h average of 0.08 ppm and 3 days in Millbrook compared to 10 in New Brunswick with a 1-h average of 0.12 ppm (3). We also conducted a greenhouse test in which hybrid poplar clone 388 was exposed to 0.17 ppm O3 for 5 h two, three, four, or five times during a 1-month period ( 4 ) . O3 did not significantly affect the growth of the seedlings. Although Wang et al. concluded that substantial growth reductions could occur in forests without accompanying visible symptoms, the notion is not supported by hybrid poplar data-Jensen and Dochinger exposed hybrid poplar to 1.0 ppm O3 for 2-8 h and found injury on 70% of the leaves, but no growth reduction. Similarly in our study cited above, injury occurred on 50% of the leaves without any growth reduction. Wang et al. cited five references (ref 20, 22, 23, 25, and 26) as evidence supporting the susceptibility of hybrid poplar to ambient ozone. Typically in these greenhouse and laboratory experiments, seedlings were exposed to 0.15
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