tainty in Risk Assessments," /. Envi ron. Eng. 1999,125 (7), 660-666) TMDL calculations. A decision sup port system was developed to calcu late total maximum daily loads of various pollutants for water qualitylimited sections within a river basin. (Chen, C. W.; Hen, J.; Ziemelis, L.; Goldstein, R. A; Olmsted, L. "Deci sion Support System for Total Maxi mum Daily Load," /. Environ. Eng. 1999, 125 (7), 653-659)
MODELING Climate change. An atmospheric gen eral circulation model reveals greater cooling than the CLIMAP project in the equatorial current systems of the eastern Pacific and tropical Adantic Oceans. (Hostetier, S. W; Mix, A. C. "Reassessment of Ice-Age Cooling of the Tropical Ocean and Atmosphere," Nature 1999,399 (6737), 673-677) α-Hexachlorocyclohexane. In both model results and observations, the dramatic decrease in global emis sions of oc-hexachlorocyclohexane is reflected in rapidly decreasing con centrations in the atmosphere and seawater, except in the Arctic Ocean. (Wania, E; Mackay O.; Li, Y.-E; Bidleman, T. E; Strand, A. "Global Chemi cal Fate of a-Hexachlorocyclohex ane. 1. Evaluation of a Global Distribution Model," Environ. Toxi col. Chem. 1999,18 (7), 1390-1399) α-Hexachlorocyclohexane. Modeling results provide a comprehensive glo bal historical picture of the global be havior of a-hexachlorocyclohexane, which, after being used in huge amounts in the early 1980s, has since been essentially eliminated. (Wania, E; Mackay, D. "Global Chemical Fate of a-Hexachlorocyclohexane. 2. Use of a Global Distribution Model for Mass Balancing, Source Apportionment, and Trend Prediction," Environ. Toxi col. Chem. 1999 18 (7)) 1400-1407)
SOILS Mercury presence. It is proposed that erosion of deforested soils following human colonization constitutes a ma jor disturbance of the natural mercurv
Heavy metal accumulation Little is known about interactions of metals with individual benthic mi crobes in nature because of the technical difficulty of studying such small-scale processes in complex, heterogeneous sedimentary eco systems. T. Jackson and coworkers used energy-dispersive X-ray micro analysis (EDXM) and transmission electron microscopy (TEM) to inves tigate the accumulation of Cu and other elements by the cell walls, cytoplasm, cytoplasmic inclusions, fibrils and mineral coatings of indi vidual bacterial cells in the sedi ments of a lake polluted with heavy metals This represents the first aDDlication of modern EDXM and TEM techniques to the systematic quantitative analysis of statistically meaningful numbers of individual bap4.prj„l cpils \A/ith separate analv ses of snpcific cell components and assn riatpri nnnlii/ing
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cycle and may explain the increase of mercury burdens in Amazonian aquatic ecosystems in newly colo nized watersheds. (Roulet, M., et al. "Effects of Recent Human Coloniza tion on the Presence of Mercury in Amazonian Ecosystems," Water, Air, SoilPollut. 1999,112 (3-4), 297-313)
WASTEWATER Disinfection-resistant bacteria. It is suggested that the oxidation towers of a wastewater treatment plant in Wil liamsburg, Va., supported growth or recovery of fecal coliform bacteria and that this bacterial subpopulation seem ed to increase resistance to routine chlorine disinfection. (Scully, E E., Jr., et al. "Development of DisinfectionResistant Bacteria During Wastewater Treatment," Water Environ. Ress.999, 71 (3)) 277-281) Reuse practices. The status of wastewater reclamation and reuse around the Mediterranean basin is presented with a discussion of exist
ing guidelines and regulations, as well as the possibility of developing uniform wastewater reuse standards. (Angelakis, A. N.; Marecos Do Monte, M.H.E; Bontoux, L.; Asano, T. "The Status of Wastewater Reuse Practice in the Mediterranean Basin: Need for Guidelines," Water Res. 1999,33 (10), 2201-2217)
WATER Contaminated fish. In a survey con ducted among anglers in New Jersey's Newark Bay Complex, it was found that although 60% of the anglers had heard about fish consumption adviso ries, they either did not believe them or were unconcerned about health effects from eating contaminated spe cies. (Pflugh, K. K.; Lurig, L.; Von Hagen L. A; Von Hagen; Burger, J. "Ur ban Anglers' Perception of Risk From Contaminated Fish" Sci. Total Envii 1999 228 (2-3), 203-218) Humic substances. Results from a variety of spectroscopic techniques suggest the incorporation of light carbon sources in the humification process, rather than 13C enrichment due to trophic effects. (Schulten, H.-R.; Gleixner, G. "Analytical Pyrolysis of Humic Substances and Dis solved Organic Matter in Aquatic Systems: Structure and Origin," Wa ter Res. 1999, 33 (11), 2489-2498) Membrane filtration. Transport mea surements of natural organic matter (NOM) rejection and flux are de scribed consistently using a resistances-in-series model that considers membrane characteristics and NOM properties. (Cho, J.; Amy, G; Pellegrino, J. "Membrane Filtration of Nat ural Organic Matter: Initial Compari son of Rejection and Flux Decline Characteristics With Ultrafiltration and Nanofiltration Membranes" Water Res. 1999 33 (11) 2517-2526) Pesticide contamination. In a study in which the ecological risks of mod ern pesticides related to different Eu ropean river/estuary systems are com pared, it is found that pesticides exert a significant pressure on the aquatic system. (Steen, R.J.CA., et al. "Ecologi cal Risk Assessment of Agrochemicals in European Estuaries," Environ. Toxi col. Chem. 1999,18 (7), 1574-1581)
NOVEMBER 1, 1999 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS » 4 7 1 A
