RESEARCH WATCH
Air quality Dioxin emissions. Because early EPA dioxin emission estimates from medical waste incinerators and cement kilns were significantly overestimated, an independent national dioxin emissions estimate for hazardous waste incinerators (HWI) was prepared to correct the errors in EPA's HWI emissions database. (Cudahy, J. J.; Rigo, H. G. "National Annual Dioxin Emissions Estimate for Hazardous Waste Incinerators," /. Air Waste Manage. Assoc. 1998 48,1107-1111)
Assessment Environmental exposure. A comprehensive epidemiologic analysis confirms that lead-contaminated house dust is the main source of childhood lead exposure. (Lanphear, B. P., et al. "The Contribution of Lead-Contaminated House Dust and Residential Soil to Children's Blood Lead Levels," Environ. Res. 1998, 79, 51-68)
Contaminants Chlorobenzenes. 1,2,3,4-tetrachlorobenzene is aerobically mineralized by a pure culture of Pseudomonas chlororaphis RW71, representing a novel tool for designing optimized microorganisms able to mineralize highly recalcitrant haloaromatic pollutants. (Potrawfke, X; Timmis, K. N.; Wittich, R-M. "Degradation of 1,2,3,4-Tetrachlorbenzene by Pseudomonas chlororaphis RW71," Appl. Environ. Microbiol. 1998, 64(10)) 3798-3806)
Toxic metal cleanup Dendrimers are highly branched polymers with controlled composition and architecture consisting of three structural components: a core, interior branch cells, and terminal branch cells. Their use provides new opportunities to develop more efficient and cost-effective functional materials for polymer supported ultrafiltration—an emerging and promising process for the treatment of water contaminated by toxic metals. M. Diallo and co-workers investigated the binding of Cu(ll) ions to poly(amidoamme) (PAMAM) dendrimers. Their results indicate that PAMAM dendrimers can serve as high-capacity nanoscale containers for toxic metal ions. Subsequent separation of metal-laden dendrimers from solutions is accomplished by ultrafiltration; the metal-laden dendrimers can be regenerated by protonating the ligands. The results also indicate that compared to conventional chelating agents, which can typically bind only one Cu(ll) ion per molecule, some dendrimers can bind more than 150 Cu(ll) ions per molecule. {Environ. Sci. Techno!., this issue, pppp.p.824)
associated with VOCs in drinking water. (Lybarger, J. A; Lee, R.; Vogt, D. P.; Perhac, R. M., Jr.; Spengler, R. E; Brown, D. R. "Medical Costs and Lost Productivity From Health Conditions at Volatile Organic Compound-Contaminated Superfund Sites," Environ. Res. 1998, 79, 9-19)
Lipophilicity. A fast molecular simulation approach is introduced to calculate the partition coefficient and logP, a measure of lipophilicity. (Reynolds, C. H.; Best, S. A. "A Fast Molecular Simulation To Calculate Lipophilicity," CHEMTECH 1998, ,11 28-34)
Health
Modeling
Household humidifiers. Residents who clean humidifiers on an infrequent basis have significantly higher odds of reporting adverse health symptoms than those who clean their humidifiers regularly. (Mohan, A. K.; Feigley, C. E.; Macera, C. A. "Humidifier Use in the Home Environment and Its Effects on Respiratory Health," Appl. Occup. Environ. Hyg. 1998, i3(ll), 782-787)
Long-range dispersion. Results from two atmospheric experiments demonstrated that the perfluorocarbon tracer technique can be applied in long-range tracer experiments up to 2000 kilometers. (Nodop, K.; Connolly, R.; Girardi, F. "The Field Campaigns of the European Tracer Experiment (ETEX): Overview and Results," Atmos. Environ. 1998, 32(24), 4095-4108)
Drinking water
Methods
Monitoring
Membrane technology. A hybrid powdered activated carbon-ultranltration process shows promise in treating a low-quality source water without sacrificing either cost or operating efficiency (Jack, A. M.; Clark, M. M. "Using PAC-UF To Treat a Low-Quality Surface Water," /. Am. Water Works Assoc. 1998, 90(11), 83-95)
Fungicide analysis. A simple and selective HPLC method for trace level analysis of dithiocarbamate fungicides and xanthogenates (dithiocarbonates) in natural waters has been developed. (Weissmahr, K. W; Houghton, C. L.; Sedlak, D. L. "Analysis of the Dithiocarbamate Fungicides Ziram, Maneb, and Zineb and the Flotation Agent Ethylxanthogenate by Ion-Pair Reversed-Phase HPLC," Anal. Chem. 1998, 70(22), 4800-4804)
Extraction methods. Accelerated solvent extraction was found to be especially advantageous over ultrasonic extraction in the case of higher multiple-pollutant exposures and the resultant complicated matrixes. (Wenzel, K-D; Hubert, A; Manz, M.; Weissflog, L.; Engewald, W.; Schuiirmann, G. "Accelerated Solvent Extraction of Semivolatile Organic Compounds From Biomonitoring Samples of Pine Needles and Mosses," Anal. Chem. 1998, 70(22)) 4827-^835)
Volatile organics. Health costs at Superfund sites are calculated at $330 million annually for conditions
MARCH 1, 1999 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 1 3 1 A
