Research Watch: Biofilms - Environmental Science & Technology

Research Watch: Biofilms - Environmental Science & Technology...

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RESEARCH WATCH Air Volatile organic compounds. Adsorption/thermal desorption with multisorbent air sampling cartridges was developed for the sensitive determination of 87 volatile organic compounds, spanning a wide range of volatilities. (Pankow, J. E; Luo, W.; Isabelle, L. M.; Bender, D. A.; Baker, R. J. "Determination of a Wide Range of Volatile Organic Compounds in Ambient Air Using Multisorbent Adsorption/Thermal Desorption and Gas Chromatography/Mass Spectrometry," Anal Chem 1998 70(24) 5213-5221)

Assessment Biofilms. Oxygen availability limits protein synthesis within a Pseudomonas aeruginosa biofilm to the upper 30 um, potentially resulting in decreased susceptibility of such biofilms to antimicrobial agents. (Xu, K. D;; Stewart, P. S.; Xia, E; Huang, C-T.; McFeters, G. A. "Spatial Physiological Heterogeneity in Pssudomonas aeruginosa Biofilm Is Determined by Oxygen Availability," Appl. Environ. Microbiol. 1998 64(10), 4035-4039) Escherichia coli. Fluorescent, in situ stains and probes were used to assess the influence of starvation on the physiological activity, membrane integrity, respiratory activity, intracellular esterase activity, and 16S rRNA content of £ coli 0157:H7. (Lisle, J. X; Broadaway, S. C ; Prescott, A. M.; Pyle, B. H.; Fricker, C.; McFeters, G. A. "Effects of Starvation on Physiological Activity and Chlorine Disinfection Resistance in Escherichia coli 0157:H7" Appl. Environ. Microbiol. 1998 64(12) 4658-4662) Methane emissions. Although uncertainties remain, estimates indicate that even in a highly urbanized region such as New England, natural sources of methane make the single greatest contribution to total emissions, with state totals varying between 8% in Massachusetts to 92% in Maine. (Blaha, D.; Bartlett, K.;

Halomethane remediation Polyhalogenated methanes (PHMs) are widely used as solvents, refrigerants, foaming agents, pesticides, and propellants and are ubiquitous pollutants in atmospheric and subsurface environments. J. Buschmann and coworkers investigated reductive dehalogenation reactions of PHMs, relevant to their potential use in waste treatment and remediation applications. Studies of the iron porphyrin and cysteine-mediated reduction of 10 PHMs in homogeneous aqueous solution revealed that for fast complete dehalogenation, use of a very reactive one-electron donor (a reactive iron species) in the presence of organic compounds exhibiting reduced sulfur and nitrogen groups avoids the formation of the less halogenated volatile compounds. Consequently, further treatment of such products is not necessary. (Environ. Sci. Techno!., this issue, pp. 1015-1020)

Czepiel, P.; Harriss, R.; Crill, P. "Natural and Anthropogenic Methane Sources in New England," Atmos. Environ. 1998, 33(2), 243-255)

Biodegradation Chlorobenzene metabolism. Genetic recombination of existing genes in aerobic bacteria leads to metabolism of chlorobenzene from groundwater. (Roelof van der Meer, J.; Werlen, C ; Nishino, S. E; Spain, J. C. "Evolution of a Pathway for Chlorobenzene Metabolism Leads to Natural Attenuation in Contaminated Groundwater," Appl. Environ. Microbiol. 1998, 64(11), 4185-4193)

Chemistry Gas chromatography. A mixture of 30 purgeable organic compounds is separated in less than 2.5 min. using a gas chromatography approach described as "fast temperature programming combined with selectivity programming." (Smith, H.; Sacks, R. D. "Column Selectivity Programming and Fast Temperature Programming for High-Speed GC Analysis of Purgeable Organic Compounds," Anal. Chem. 1998, 70(23), 4960-4966)

Contaminants Organochlorine compounds. Unhatched eggs and plasma samples from prefledged bald eagles of a recovering population in the Canadian

Great Lakes basin area were contaminated with organochlorine compounds at levels comparable to those reported for eagle populations in several areas of the United States. (Donaldson, G. M.; Shutt, J. L.; Hunter, P. "Organochlorine Contamination in Bald Eagle Eggs and Nestlings From the Canadian Great Lakes," Can. Arch. Environ. Contam. Toxicol. 1999, 36(1), 70-80)

Landfill Decomposition. Studies of landfill waste found that carbohydrates such as cellulose and starch were the quickest degrading portions of waste, and samples with high lignin contents degraded more slowly than samples with lower lignin contents. (Baldwin, T. D.; Stinson, J.; Ham, R. K. "Decomposition of Specific Materials Buried Within Sanitary Landfills," /. Environ. Eng. 1998, 124(12), 1193-1202)

Measurements Atmospheric particles. Measurements of atmospheric particles in an urban area in the United Kingdom have been made, including particle number count, particle size distributions, total particle Fuchs surface area, and particle mass. (Harrison, R. M.; Jones, M.; Collins, G. "Measurements of the Physical Properties of Particles in the Urban Atmosphere," Atmos. Environ. 1998, 33(2), 309-321)