Themophilic biofiltration of methanol and alpha-pinene.

Biofiltration systems utilizing thermophilic (55 degrees C) bacteria were constructed and tested for the removal of methanol and alpha-pinene--two important volatile organic compounds (VOCs) in the forest products industry. Thermophilic bacterial mixtures that can degrade both methanol and alpha-pinene were obtained via enrichment techniques. Two bench-scale thermophilic biofiltration systems (1085 and 1824 cm3) were used to examine compound removals at different residence times, with influent concentrations of 110 ppmv methanol and 15 ppmv alpha-pinene. At a residence time of 10.85 min, the smaller system had removal efficiencies of >98% for methanol, but only 23% for alpha-pinene. The larger system was operated with the same parameters to evaluate residence time and surfactant effects on compound removals. At a residence time of 18.24 min, both methanol and alpha-pinene removal rates were > or = 95%. However, a-pinene removal dropped to 26% at a residence time of 6.08 min; methanol removal was not affected. Subsequent addition of a surfactant mixture increased a-pinene removal to 94% at the shortest residence time. No residual alpha-pinene was detected with the support medium Celite R-635, indicating that the surfactant may increase mass transfer of alpha-pinene.

Interlaboratory comparison of HPLC-fluorescence detection and GC/MS: analysis of PAH compounds present in diesel exhaust.

For laboratories involved in polycyclic aromatic hydrocarbon (PAH) analyses in environmental samples, it is very useful to participate in interlaboratory comparison studies which provide a mechanism for comparing analytical methods. This is particularly important when PAH analyses are routinely done using a single technique. The results are reported for such an interlaboratory comparison study, in which the four selected participating laboratories quantitatively analyzed several PAH compounds in diesel exhaust samples. The samples included particle and vapor phase extracts collected and prepared at Michigan Technological University (MTU PE and MTU VE, respectively), a diesel particle extract prepared by the National Institute for Standards and Technology (NIST, SRM 1975), and a fully characterized diesel particle sample (NIST SRM 1650). One of the laboratories used only HPLC-FLD, one used only GC/MS and two laboratories used both methods for the routine analysis of PAH in environmental samples. Data were obtained for five PAH compounds: fluoranthene, pyrene, benz[a]anthracene, benzo[a]pyrene, and benzo[g, h,i]perylene. The mean PAH levels found for SRM 1650 were outside the range reported by NIST. The range in the reported means was from 24% lower than certified for benz[a]anthracene to 41% higher for benzo[g,h,i]perylene. For the previously uncharacterized samples in this study (SRM 1975, MTU PE and MTU VE), two-thirds of the reported results were higher for the HPLC-FLD method than for the GC/MS. The range in differences between methods was from-54 to+31% calculated as the difference in GC/MS value relative to the HPLC value for each of the compared compounds. Coefficients of variation for the uncharacterized samples appeared to be higher, in most (but not all) cases, for the HPLC-FLD than for the GC/MS. The resolution of certain PAH isomers (e.g. benz[a]anthracene and chrysene, or the benzofluoranthenes), was better, as expected, for HPLC than for GC. Generally lower detection limits (by an order of magnitude or more) were reported for GC/MS than for HPLC-FLD. On the basis of this limited study, it seems as though significant differences may exist between laboratories, if not between methods, in the analysis of certain PAH compounds in real diesel samples by HPLC-FLD compared to GC/MS. If possible, measurements should be made using both methods. This is particularly important where potential interferences are undefined or subject to change, as is frequently the case with real environmental samples.

Characterization of fuel and aftertreatment device effects on diesel emissions.

Heavy-duty diesel engines operated with a low-sulfur (LS)* fuel and either a particle trap or an oxidation catalytic converter (OCC) have been studied during steady-state operation (and during regeneration of the particle trap) to determine the effects of these devices on regulated and unregulated emissions, including the chemical and biological character of the exhaust. This study consisted of two phases, both of which were designed to determine the effects of fuel, particle control system, and engine type on (1) levels of regulated emissions such as oxides of nitrogen (NOx), total hydrocarbons (HC), and total particulate matter (TPM); (2) levels of unregulated emissions such as particle-associated soluble organic fraction (SOF), sulfate (SO4), solids (SOL), and the vapor-phase organic fraction collected on XAD-2 resin (XOC); (3) levels of selected mutagenic and carcinogenic polynuclear aromatic hydrocarbons (PAHs) in the particle-associated and vapor-phase organic fractions; (4) mutagenic activity associated with the same organic fractions; and (5) exhaust particle size distributions. Phase I involved a 1988 Cummins Engine Co. LTA 10-300 (L10) engine equipped with a ceramic particle trap having built-in regeneration controls. Phase II involved a 1991 prototype Cummings Engine Co. LTA 10-310 (LTA) engine equipped with an OCC. The 1991 LTA engine also contained a higher pressure fuel-injection system than the 1988 L10 engine and used an intake charge air-to-air aftercooling system, instead of the intake air-intercooler system on the 1988 engine.

Characterization of particle- and vapor-phase organic fraction emissions from a heavy-duty diesel engine equipped with a particle trap and regeneration controls.

The effects of a ceramic particle trap on the chemical and biological character of the exhaust from a heavy-duty diesel engine have been studied during steady-state operation and during periods of trap regeneration. Phase I of this project involved developing and refining the methods using a Caterpillar 3208 engine, and Phase II involved more detailed experiments with a Cummins LTA10-300 engine, which met Federal 1988 particulate matter standards, and a ceramic particle trap with built-in regeneration controls. During the Phase I experiments, samples wee collected at the Environmental Protection Agency (EPA)* steady-state mode 4 (50% load at intermediate speed). Varying the dilution ratio to obtain a constant filter-face temperature resulted in less variability in total particulate matter (TPM), particle-associated soluble organic fraction (SOF), solids (SOL), and polynuclear aromatic hydrocarbon (PAH) levels than sampling with a constant dilution ratio and allowing filter-face temperature to vary. A modified microsuspension Ames assay detected mutagenicity in the SOF samples, and in the semivolatile organic fraction extracted from XAD-2 resin (XAD-2 resin organic component, XOC) with at least 10 times less sample mass than the standard plate incorporation assay. Measurement techniques for PAH and nitro-PAH in the SOF and XOC also were developed during this portion of the project. For the Phase II work, two EPA steady-state rated speed modes were selected: mode 11 (25% load) and mode 9 (75% load). With or without the trap, filter-face temperatures were kept at 45 degrees +/- 2 degrees C, nitrogen dioxide (NO2) levels less than 5 parts per million (ppm), and sampling times less than 60 minutes. Particle sizes were determined using an electrical aerosol analyzer. Similar sampling methods were used when the trap was regenerated, except that a separate dilution tunnel and sampling system was designed and built to collect all of the regeneration emissions. The SOF and XOC were extracted from their collection media with dichloromethane. Levels of 12 PAH and nitro-PAH compounds with known biological effects were determined using high-pressure liquid chromatography with fluorescence detection. Two additional dinitro-PAHs were analyzed semi-quantitatively, and several representative SOF and XOC samples were screened for three additional PAH compounds. Mutagenicity was assessed using the modified Ames microsuspension assay.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of organic extracts from standard reference materials 1649, 'urban dust/organics,' and 1650, 'diesel particulate matter', using a microsuspension assay. A WHO/IPCS/CSCM study.

Mutagenicity associated with replicate organic extracts from standard reference materials 1649 'urban dust/organics' (air particles), and 1650, 'diesel particulate matter' (diesel particles), was determined using a Salmonella microsuspension assay. The results indicate that the mutagenicity of samples such as these can readily be determined using the microsuspension assay with only 5% of the mass required for the standard plate incorporation assay. In general, 80% of the variation in mutagenic activity was due to the bioassay procedure and 20% to the extraction process. Extracts from both samples had primarily direct-acting mutagenicity as there were no significant differences in responses with and without metabolic activation (S9). The TA98-S9 mean air particles mutagenic activities (C.V., %) based on mass of extractable organics or particles were 4.4 (4.7%) and 0.29 (3.6%) revertants/micrograms, respectively, and for the diesel particles were 66 (44%) and 12 (29%) revertants/microgram, respectively. More of the observed direct-acting mutagenicity in the diesel particles extracts was due to nitro-substituted compounds because there were significant reductions in activity with TA98NR (45% of TA98 -S9) and TA98-1,8-DNP6 (21% of TA98 -S9). In the air particles extracts, the TA98NR activities were not significantly different from TA98 -S9 but the TA98-1,8-DNP6 levels were.

An investigation into the effect of a ceramic particle trap on the chemical mutagens in diesel exhaust.

Diesel exhaust particles and vapor phase samples were collected from the diluted (15:1) exhaust of a 10.4 L displacement medium-duty engine (Caterpillar 3208), operated under EPA steady-state cycle Modes 4 and 5 conditions for load (50 and 75 percent, respectively) and speed (1680 rpm). Baseline (uncontrolled) emissions were compared to the exhaust modified by the use of an uncatalyzed monolithic ceramic trap (Corning). The Salmonella/microsome mutagenicity bioassay (Ames Test) was used to direct the course of chemical analyses. Total particulate matter (TPM), soluble organic fraction (SOF) (from TPM), sulfate fraction (SO4) (from TPM), and solid fraction (SOL) (from particle) were determined from dilute exhaust particles collected on 47 mm Teflon-coated woven glass fiber filters. Coincidentally, particles were collected on 508 x 508 mm Teflon-coated non-woven glass fiber filters, and vapor-phase samples were collected on XAD-2 resin. The SOF and VOC for chemical and biological characterization were obtained by Soxhlet extraction of samples with dichloromethane (DCM). Hydrocarbon mass balances were developed to evaluate the efficiency of the sampling system. Use of the ceramic traps caused no change in engine total hydrocarbon (HC) levels at Mode 4 but decreases in TPM, SOF, and NO2 were noted. In terms of HC emissions only, the percentage of SOF was significantly reduced, but the percentage of VOC was unchanged. For Mode 5, the engine HC levels were significantly reduced but the proportions of HC components, i.e. the percentage of SOF and the percentage of VOC, did not change significantly. Engine emission levels of TPM, SOF, and nitrogen dioxide (NO2) were also significantly reduced at Mode 5. At both Modes 4 and 5, use of the ceramic particle traps caused an increase in the direct-acting (TA98) mutagenicity (revertants/microgram) of the SOF and a decrease in the activity of the VOC. The traps caused a 70 percent reduction of TPM at Mode 4 but only a 45 percent reduction in particulate-associated direct-acting mutagenicity on the basis of raw exhaust emissions (kRevertants/m3). At Mode 5 with the traps, there was an 85 percent reduction in TPM and only a 25 percent reduction in the activity of the SOF. The direct-acting mutagenicity of the VOC was reduced by use of the traps by 40 and 65 percent (kRevertants/m3) for Modes 4 and 5, respectively. In contrast, the indirect-acting mutagenicity of the Mode 4 VOC increased nearly 150 percent. Filter loading and reexposure experiments indicated that sampling artifacts did not contribute to the SOF mutagenicity at Mode 4.(ABSTRACT TRUNCATED AT 400 WORDS)

Habitat association of Klebsiella species.

The genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that "K. pneumoniae" actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae--humans, animals, sewage, and polluted waters and soils; K. oxytoca--frequent association with most habitats; K. terrigena--unpolluted surface waters and soils, drinking water, and vegetation; K. planticola--sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis--infrequently detected (primarily with humans).

Primary Klebsiella identification with MacConkey-inositol-carbenicillin agar.

MacConkey-inositol-carbenicillin agar has successfully been used as a primary selective medium for Klebsiella enumeration. With pure cultures, nearly 100% recovery of Klebsiella was observed by membrane filtration. With environmental samples using membrane filtration, 95% of typical pink- to red-colored colonies were verified as Klebsiella, as opposed to only 1% of yellow background colonies. Recovery of Klebsiella on MacConkey-inositol-carbenicillin agar was as good or better than on mEndo agar LES (Difco Laboratories). Recovery and percent colony confirmation with MacConkey-inositol-carbenicillin agar were greater than for other proposed Klebsiella selective media.

Isolation of Klebsielleae from within living wood.

Previous studies from this laboratory have documented the presence of coliform bacteria emanating from wooden reservoirs containing finished drinking water. Coliforms were identified as Klebsiella pneumoniae and Enterobacter spp. In the present report, evidence is presented which suggests that the origin of these coliforms is from the wood used to construct the reservoirs. In liquid expressed from freshly cut redwood, total bacterial counts in the range of 10(5) to 10(6)/ml were commonly observed. When present, coliform counts were over 10(3)/ml of expressed liquid. E. agglomerans was the most prevalent coliform present, but Klebsiella was isolated from freshly cut logs. Citrobacter freundii was also occasionally isolated. No fecal coliform-positive Klebsiella were obtained from any of the samples. Highest total bacteria and coliform counts were observed in sapwood specimens. Coliforms were present throughout sapwood as evidenced by contact plating serial sections of freshly cut wood. Scanning electron micrographs illustrate the presence of bacterial colonies within sapwood tracheids. Other wood species also contained coliform bacteria but in numbers lower than found in redwood.

Significance of fecal coliform-positive Klebsiella.

A total of 191 Klebsiella pneumoniae isolates of human clinical, bovine mastitis, and a wide variety of environmental sources were tested for fecal coliform (FC) response with the membrane filtration and most probable number techniques. Twenty-seven Escherichia coli cultures of human clinical and environmental origins were also tested. Eighty-five percent (49/58) of known pathogenic K. pneumoniae were FC positive, compared with 16% (19/120) of the environmental strains. E. coli results indicated 93% (13/14) of the clinical and 85% (11/13) of the environmental strains as FC positive. There was no significant difference in the incidence of FC-positive cultures between pathogenic Klebsiella and E. coli. pH measurements of K. pneumoniae and E. coli cultures growing in m-FC broth at 44.5 degrees C revealed three distinct pH ranges correlating with colony morphology. beta-Galactosidase assays of Klebsiella and E. coli cultures at 44.5 degrees C indicated all were able to hydrolyze lactose, even if they were FC negative by the membrane filtration or most probable number techniques. The FC response pattern appears stable in K. pneumoniae. Three pathogenic cultures showed no change in FC responses after 270 generations of growth in sterile pulp mill effluent. Since K. pneumoniae is carried in the gastrointestinal tract of humans and animals and 85% of the tested pathogenic strains were FC positive, the isolation of FC-positive Klebsiella organisms from the environment would indicate their fecal or clinical origin or both. The added fact that K. pneumoniae is an opportunistic pathogen of increasing importance makes the occurrence of FC-positive environmental Klebsiella, particularly in large numbers, a potential human and animal health hazard.

Klebsielleae in drinking water emanating from redwood tanks.

A survey was made of the bacteriological quality and chlorine content of 33 public and private water systems that utilize redwood storage tanks. Coliforms of the genera Klebsiella and Enterobacter were isolated from 9 of 10 private drinking water systems and from 11 of 23 water systems in state and federal parks. Total coliform counts in the private systems exceeded federal membrane filter guidelines by as much as 10-to 40-fold. Coliform counts were highest in the newer reservoirs. Factors contributing to poor water quality are: lack of automated chlorination equipment or an insufficient supply to maintain a residual, common inlet/outlet plumbing design, and lengthy average retention periods. The latter two factors contribute to improper mixing and stagnation of the water, whereas the former allows microbes to multiply on the water-soluble nutrients that leach from the wood. Wooden reservoirs exert a high chlorine demand, and 0.4 ppm of chlorine residual in the incoming tank water proves inadequate. It is suggested that specific water-soluble nutrients in redwood (and in numerous other types of botanical material) induce a natural nutritional selection for coliforms of the tribe Klebsielleae.