RESEARCH WATCH
AIR Ozone biocide activity There has been increased consumer and commercial interest in the use of ozone generators to clean or treat indoor air. However, little research data are available that report on ozone's biocidal activity in gas-phase applications. K. K. Foarde and coworkers investigated ozone's effect on suspensions of vegetative fungi and spore-forming fungi and bacterium in prototype laboratory chamber tests and on actual building materials used as test surfaces. Results indicate that significant reduction of surface biocontaminants is not achieved at ozone concentrations below 6-10 The authors note that the threshold limit value for ootential health impacts associated with short-term exposure to ozone has a ceiline limit of 0 1 ppm (Awl Occuvt Environ Hve .199 ,7(d) 535-42)
BlODEGRADATION Novel cyanide treatment Cyanide in solid wastes and industrial wastewater is toxic and must be reduced to low levels before discharge; however, chemical treatment systems are disadvantaged because of technological demands, process costs, and disposal considerations. A. Dumestre and colleagues used Fusciriufn solcini, a fungus, to biodegrade cyanide under alkaline conditions. Cyanide was degraded by a two-step mechanism converging cvanide to formamide by cyanide hydratase, followed by converging formamide to formate with fungal growth. The latter step was heavily influenced by the presence of organic nutrients. The method limits risks of cyanhydric acid volatilization and is widely applicable to treatment of cyanide-laden effluents and wastes. (Appl. Environ. Microbiol. 1997, 63(7), 272-34)
Metal complexation characterized In aquatic systems, the toxicity and mobility of chromium and thallium depend on their state of oxidation and are influenced by the formation of metal ion-humic acid complexes. 6. Bidoglio and co-workers evaluated metal ion binding to humic acids by using continuous emission and synchronous fluorescence measurement techniques to monitor quenching of humic acid luminescence caused by metal-humic acid interactions. Modeling and data analysis provided intrinsic binding constants for each metal that were independent of pH, metal-ligand ratio, and choice of measurement technique. These results demonstrate the resolving power and reliability of data treatment techniques and confirm the utility of simultaneous fluorescence measurement methods for monitoring metal ion-humic acid interactions at low metal concentrations. (Environ. Sci. Technol..,his iisue, ,pp .536-43)
Resin acid removal Chlorinated dehydroabietic acids are formed during chlorine bleaching of wood pulp. Although they are very toxic to fish and can bioaccumulate, little is known about how these resin acids biodegrade. W. W. Mohn and G. R. Stewart studied the ability of 12 resin-degrading bacteria strains to grow on these chlorinated acids as sole organic substrates. Several of the bacterial strains investigated exhibited a range of growth and acid biodegradation on monochlorinated acids but no strains used dichlorinated acids as a sole substrate These results suggest potentisI 11 cp
of some bacteria for biodegradation of monochlorinated resin acids but effective degradation of dichlorinated dehydroabietic acids by biological treatment aDDears doubtful {AnnI Fnvirnn Microbiol 1997 63(W 3014-201
HEALTH Airway disease study Indoor microbial growth is associa t c U w i t l i i1 lC-rfcrcioCUriolv Ul t i l r w a y
disease. To assess wherner (_i—7oj-u~ n-glucan, a cell-wall component of molds, is a causative agent for observed effects, R. Rylander studied changes in symptoms and responses among day-care workers before and after renovation of the building they
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occupied. After renovation, levels of (1—>3)-(3-D-glucan decreased significandy, and fewer individuals reported symptoms. On the basis of these results, Rylander suggests (1—>3)-P-Dglucan may be a causative agent associated with indoor air pollution and recommends further research to determine whether the substance is simply a surrogate indicator of the presence of mold spores or other causative agents. (Arch. Environ. Health 1997, 52(4), 281-85)
Hazardous site exposure Studies of environmental exposures indicate a link between congenital malformations and exposure to chemicals found in waste sites. Little information is available about associations between health effects and residential proximity to sites. L. Croen and colleagues used data from two population-based, case-control studies to investigate whether site proximity increased the risk of neural tube defects, conotruncal heart defects and oral cleft defects in California. Results suggest no elevcited risk for residence in census tracts that contain a waste site. However, elevated risks were found for neural tube and heart defects for residents living within one-quarter mile of a National Priority List waste site. Similarly, although no direct measurements were made of actual exposures, elevated risks for defects were associated with residence within one mile of National Priority List sites
0013-936X/97/0931-544A$14.00/0 © 1997 American Chemical Society
