ES&T
OUTLOOK Report from the fall ACS meeting Five symposia at the Kansas City meeting addressed the environmental chemistry related to pressing problems. Symposia topics included: • the environmental fate of an thropogenic organic pollutants; • the identification and analysis of organic pollutants in air; • processes for the biological mod ification of wastes; • safety and health considerations at hazardous waste sites; and • chlorinated dioxins and dibenzofurans in the environment. This report describes the first three symposia. Fate of pollutants Fugacity works. In a session on the environmental fates of anthropogenic organic pollutants, Donald Mackay and Λ. Bobra of the University of To ronto reported on a study in which they designed, constructed, and operated a completely controlled microecosystem of air, water, soil, sediment, and biota. They introduced a pulse of toxic sub stance into the system and measured the kinetics and "relaxation" toward equilibrium distribution. These mi crocosms were maintained in the dark under nearly bacteria-free conditions at 20° C and allowed to come to equi librium for 96 h before a compound was introduced into the system. Sam ples from the microcosm were ana lyzed by gas or liquid chromatography. The correspondence between the ex perimental and calculated data was judged to be satisfactory, thus lending support to the use of the fugacity modeling approach for predicting the environmental behavior of chemi cals. Michael R. Hoffmann and Marianna Plastourgou of Caltech recently developed a simple, mass transport model to predict the relative degree of hydrolysis of parathion in a twolayered flow system. Trace metal cat 0013-936X/82/0916-0601 A$01.25/0
alysts are present in one layer and a reactant (such as parathion) is present in the other density-stratified layer. This simplified model for interdiffusion provides a useful starting point for more elaborate models of transport with chemical reaction in a layered flow system. For many years, sediments were considered to be permanent sinks for hydrophobic pollutants of low water solubility, polychlorinated biphenyls (PCBs), for example. However, Steven J. Eisenreich and colleagues at the University of Minnesota presented recent data suggesting biotic recycling and sediment resuspension. The transport and fate of high mo lecular weight organics in the atmo sphere is, to a large extent, controlled by volatility. Terry F. Bidleman and
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© 1982 American Chemical Society
W. Neil Billings of the University of South Carolina summarized five years of research on the atmospheric trans port and removal of chlorinated pes ticides and PCBs in continental, coastal, and open-ocean environ ments. Hazardous materials in fish Since 1974, the Environmental Research Laboratory in Duluth, Minn., has been involved in gas chromatography/mass spectrometry ( G C / M S ) exploratory studies of syn thetic organic chemicals in fish from the Great Lakes and other major U.S. watersheds. D.W. Kuehl and col leagues at the ΕΡΛ Environmental Research Laboratory in Duluth re ported that the data are subjected to a pattern recognition approach in order
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to interpret those obtained from high-resolution gas chromatography. The output of this pattern recognition shows a detailed postanalysis report of the compound results. The output can be given in tabular form or as a multicolor histogram that shows both the original sample chromatograph and a chromatogram of the calculated mixture of PCBs present. The origin of many of these chemicals often remains unknown. But polychlorinated styrènes comprise one class of compounds that has been observed in fish from the Great Lakes since 1974. This class of compounds has also been found in fish and birds in Europe. Organics in dump sites Another current environmental problem is the spread of pollution from chemical dump sites. Ronald A. Hites and Ray Kaminsky of Indiana University measured the spread of chemical pollution from dumps of the city of Niagara, N.Y., into the Niagara River and downstream in Ontario. Analyses of sediment cores and grab samples from Lake Ontario have revealed a variety of halogenated organic compounds that appear to be accumulating in increasingly large quantities. The analytical technique that worked best was N C I G C / M S , negative chemical ionization mass spectrometry combined with fused silica, capillary column gas chromatography. Other sources of naturally occurring organics are aquatic humic materials from decaying leaves and other decaying organic matter. These materials represent an important fraction of the organic content of streams. D. L. Norwood and colleagues at the University of North Carolina at Chapel Hill reported quantitative yields of more than 30 by-products from a reaction of an aquatic fulvic acid with aqueous chlorine. Furthermore, synthetic organic chemicals in aquatic systems tend to sorb to solid materials such as sediments and suspended solids. Once absorbed, they undergo transport and transformation processes different from those they would have undergone in the dissolved state. The role of such partitioning reactions is of concern in the process of bioaccumulation, in which hydrophobic pollutants concentrate at the highest levels of the food chain. T. C. Voice and colleagues at the University of Michigan in Ann Arbor performed laboratory, isotherm experiments using four hydrophobic organic compounds with varying octanol-water partition coefficients and three sedi602A
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ments collected from Lake Michigan, with solids concentrations ranging from 10 m g / L to 400 m g / L . The data suggest that the experiments conducted at high solids levels for the sake of analytical simplicity may substantially underpredict environmental partitioning. Visibility studies In a study of the visibility and air quality relationships in St. Louis, Edward S. Macias of Washington University and Lih-Ching Chu of the Illinois State Water Survey said that particle size, shape, and refractive index are the most important parameters for relating the concentration of particles to their optical properties. According to the current understanding, the size distribution of atmospheric aerosol mass is generally bimodal, and light scattering and particle-related light absorption are usually dominated by fine mode aerosol. The significance of the carbonaceous compounds' contribution to visibility, especially scattering, is not well understood. No obvious relationship between humidity and light scattering due to different chemical species has been found in this work. In summary, the relative contributions to visibility impairment in St. Louis are 49% from the scattering of sulfates, 14% from the absorption of elemental carbon, 6% from the scattering of elemental carbon, 11 % from the scattering of organic carbon, and 12% from the scattering of the remainder of the fine mass. About 20% of the visibility reduction in St. Louis was caused by elemental carbon, which
accounts for only 6% of the fine mass. Biological monitoring An international pilot study, sponsored by the World Health Organization, the United Nations Environment Programme, and the EPA aims to assess the baseline body burden levels of two metals, cadmium and lead. Ten countries including the U.S. are participating in the study of a nonoccupationally exposed population—school teachers in metropolitan areas. First, a questionnaire was used to collect basic demographic and medical information on possible sources of exposure to these metals. These data will be useful for examining possible correlations between body burden and exposure. Another element of the study was the collection of kidney cortex specimens. The scientific literature indicates that the kidney is the site of lifetime cadmium accumulations. Earlier studies on the human blood levels of lead and cadmium and the cortex level of cadmium had been performed, but none had been attempted on an international level. The U.S. phase of this international study was conducted in Baltimore, Md. Some 224 questionnaires were mailed, and 180 teachers submitted to a chemical analysis of their blood for the levels of cadmium and lead. Preliminary results are shown in the table. Organic pollutants in the air Thomas R. Hauser, director of the EPA Environmental Monitoring Sys-
TABLE
Estimated lead and cadmium concentrations in selected subgroups Estimated mean
