Characterization of ambient fine particles in the northwestern area and Anchorage, Alaska

Ambient PM2.5 (particulate matter less than 2.5 microm in aerodynamic diameter) in the northwestern United States and Alaska is dominated by carbonaceous compounds associated with wood burning and transportation sources. PM2.5 source characterization studies analyzing recent PM2.5 speciation data have not been previously reported for these areas. In this study, ambient PM2.5 speciation samples collected at two monitoring sites located in the northwestern area, Olympic Peninsula, WA, and Portland, OR, and one monitoring site located in Anchorage, AK, were characterized through source apportionments. Gasoline vehicle, secondary sulfate, and wood smoke were the largest sources of PM2.5 collected at the Anchorage, Olympic, and Portland monitoring sites, respectively. Secondary sulfates showed an April peak at Anchorage and a November peak at Portland that are likely related to the increased photochemical reaction and long-range transport in Anchorage and meteorological stagnation in Portland. Secondary nitrate at the Olympic site showed a weak summer high peak that could be caused by seasonal tourism in the national park. Backward trajectories suggested that the elevated aged sea salt concentrations at the Portland monitoring site could be regional transport of sea salt that passed through other contaminated air sheds along the coast. Oil combustion emissions that might originate from ships and ferries were observed at the Olympic monitoring site.     

Characterization of real-world activity, fuel use, and emissions for selected motor graders fueled with petroleum diesel and B20 biodiesel

Motor graders are a common type of nonroad vehicle used in many road construction and maintenance applications. In-use activity, fuel use, and emissions were measured for six selected motor graders using a portable emission measurement system. Each motor grader was tested with petroleum diesel and B20 biodiesel. Duty cycles were quantified in terms of the empirical cumulative distribution function of manifold absolute pressure (MAP), which is an indicator of engine load. The motor graders were operated under normal duty cycles for road maintenance and repair at various locations in Wake and Nash Counties in North Carolina. Approximately 3 hr of quality-assured, second-by-second data were obtained during each test. An empirical modal-based model of vehicle fuel use and emissions was developed, based on stratifying the data with respect to ranges of normalized MAP, to enable comparisons between duty cycles, motor graders, and fuels. Time-based emission factors were found to increase monotonically with MAP. Fuel-based emission factors were mainly sensitive to differences between idle and non-idle engine operation. Cycle average emission factors were estimated for road "resurfacing," "roading," and "shouldering" activities. On average, the use of B20 instead of petroleum diesel leads to a negligible decrease of 1.6% in nitric oxide emission rate, and decreases of 19-22% in emission rates of carbon monoxide, hydrocarbons, and particulate matter. Emission rates decrease significantly when comparing newer engine tier vehicles to older ones. Significant reductions in tailpipe emissions accrue especially from the use of B20 and adoption of newer vehicles.     

Effects of oyster shell on soil chemical and biological properties and cabbage productivity as a liming materials

Oyster shell, a byproduct of shellfish-farming in Korea and containing a high amount of CaCO(3), has a high potential to be used as a liming material in agriculture. However, the agricultural utilization of oyster shell is limited due to its high concentration NaCl. The oyster-shell meal collected had a low concentration of water soluble NaCl (mean 2.7 g kg(-1)), which might be a result of stacking the material for 6 months in the open field. It has a very similar liming potential with calcium carbonate, with 3.4 and 3.8 Mg ha(-1) for silt loam (SiL, pH 6.2) and sandy loam (SL, pH 5.8) to bring the soil pH to 6.5, respectively. To determine the effect of crushed oyster-shell meal on improving soil chemical and biological properties and crop plant productivity, oyster-shell meal was applied at rates of 0, 4, 8, 12, and 16 Mg ha(-1) before transplanting Chinese cabbage (Brassica campestris L.) in the two soils mentioned above. Soil pH was significantly increased to 6.9 and 7.4 by 16 Mg ha(-1) shell meal application (4 times higher level than the recommendation) in SiL and SL, respectively, at harvesting stage. The effect of liming was found higher in SL compared to SiL soil, probably due to the different buffering capacity of the two soils. The concentration of NaCl and EC value of soils were found slightly increased with shell meal applications, but no salt damage was observed. Oyster-shell meal application increased soil organic matter, available P, and exchangeable cations concentrations. The improved soil pH and nutrient status significantly increased the microbial biomass C and N concentrations and stimulated soil enzyme activities. With the exception of acid phosphomonoesterase (PMEase) activity, which decreased with increasing soil pH in SL but slightly increased in SiL, the activities of urease and alkali PMEase increased markedly with increasing soil pH by shell meal application. The improved soil chemical and biological properties resulted in increased crop productivity. The highest yield in Chinese cabbage was achieved following the application of 8 Mg ha(-1) oyster-shell meal. Conclusively, crushed oyster shell could be used as an alternative liming material to restore the soil chemical and microbial properties in upland soil and to increase crop productivity.     

Preparation of Alginic Acid and Metal Alginate from Algae and their Comparative Study

Alginic acid and metal alginates are prepared from fresh algae using extraction method. A FTIR spectrum indicates that alginic acid is converted into the metal alginate. Comparing calcium and cobalt alginates, asymmetric stretching of free carboxyl group of calcium alginate at 1630 cm⁻¹ is shifted to 1585 cm⁻¹ in cobalt alginate, due to the change of charge density, radius and atomic weight of the cation, creating a new environment around the carbonyl group. The strong exothermic peak of alginic acid in DSC thermogram indicates the decomposition of biopolymer, whereas strong exothermic peak of metal alginate in DSC thermogram attributed to the decomposition of biopolymer and formation of respective carbonate. Based on DSC study, the decomposition of cobalt alginate occurs at higher temperature comparing to those of sodium and calcium alginate, which may conclude into the higher stability of cobalt alginate. TGA results reveal that, cobalt alginate is more stable than calcium and sodium alginate at 300 °C temperature. Surface morphology (at same magnification), as well as porosity (%) and pore size distribution results change with metals present in different metal alginates.     

Determination of antibiotic compounds in water by on-line SPE-LC/MSD

This study attempts to provide an improved approach for the analysis of antibiotics, which normally exist at low concentration in complex matrices such as receiving streams of wastewater treatment plant discharge. The analytical method developed in this study combines an existing pretreatment technique of solid-phase extraction (SPE) with liquid chromatography mass spectrometry (LC/MSD) through on-line connection. The on-line connection suppressed the target loss by keeping the cartridge from drying, which resulted in improvement of the recovery and saving of the analytical time. For the on-line solid-phase extraction of 10 ml water samples, recoveries were between 74.3% and 116.5% and average LOQ was 0.11 microg l(-1) for the sulfonamide antibiotics (SA) and 0.09 microg l(-1) for the tetracycline antibiotics (TA). Application of the developed method for the analysis of fourteen antibiotics revealed that several antibiotics were detected at concentrations above the LOQ in ARW. Treated and untreated sewage and agricultural wastewater were mostly responsible for the antibiotics contamination of the river. Antibiotics were detected at much higher concentrations in the agricultural wastewater sample than in the sewage sample, implying substantial use of antibiotics in the agricultural industry. Wastewater treatment was generally effective in separation of the antibiotics tested in this study. The extent of the treatment depended on the type of antibiotics. Hydrophobic antibiotics were more effectively separated from the solution than hydrophilic antibiotics.     

Excess copper induced physiological and proteomic changes in germinating rice seeds

Copper is an essential micronutrient for plants. Present at a high concentration in soil, copper is also regarded as a major toxicant to plant cells due to its potential inhibitory effects against many physiological and biochemical processes. The interference of germination-related proteins by heavy metals has not been well documented at the proteomic level. In the current study, physiological, biochemical and proteomic changes of germinating rice seeds were investigated under copper stress. Germination rate, shoot elongation, plant biomass, and water content were decreased, whereas accumulation of copper and TBARS content in seeds were increased significantly with increasing copper concentrations from 0.2mM to 1.5mM followed by germination. The SDS-PAGE showed the preliminary changes in the polypeptides patterns under copper stress. Protein profiles analyzed by two-dimensional electrophoresis (2-DE) revealed that 25 protein spots were differentially expressed in copper-treated samples. Among them, 18 protein spots were up-regulated and 7 protein spots were down-regulated. These differentially displayed proteins were identified by MALDI-TOF mass spectrometry. The up-regulation of some antioxidant and stress-related proteins such as glyoxalase I, peroxiredoxin, aldose reductase, and some regulatory proteins such as DnaK-type molecular chaperone, UlpI protease, and receptor-like kinase clearly indicated that excess copper generates oxidative stress that might be disruptive to other important metabolic processes. Moreover, down-regulation of key metabolic enzymes like alpha-amylase or enolase revealed that the inhibition of seed germinations after exposure to excess copper not only affects starvation in water uptake by seeds but also results in failure in the reserve mobilization processes. These results indicate a good correlation between the physiological and biochemical changes in germinating rice seeds exposed to excess copper.     

Performance of an immobilized cell biofilter for ammonia removal from contaminated air stream

The performance of a lab scale biofilter packed with biomedia, encapsulated by sodium alginate and polyvinyl alcohol was used for treating ammonia (NH(3)) gas at different loading rates. The metabolic end products during NH(3) oxidation were NH(4)(+), NO(3)(-) and NO(2)(-). It is noteworthy to mention that the immobilized cell biofilter required no separate acclimatization period and showed high removal efficiencies during the start of continuous experiments. The removal efficiency was nearly 100% when ammonia loading was 4.5gm(-3)h(-1) and the maximum elimination capacity achieved in this study was 5.5gNH(3)m(-3)h(-1) at a loading rate of 7.5gm(-3)h(-1). Shock loading studies were carried out to ascertain the response of the immobilized cells to fluctuations in inlet concentration and flow rate. The inlet loading rates were varied between 0.05 and 6gNH(3)m(-3)h(-1) during this phase of operation. The biofilter responded effectively to these shock loading conditions and recovered rapidly within 4-8h. Pressure drop values were consistently less and insignificant. The results from this study indicated that this immobilized cell biofilter could be considered as a potential option to treat NH(3) under steady and transient state operation.     

Inactivation of Escherichia coli in the electrochemical disinfection process using a Pt anode

Recently, the electrochemical disinfection has gained a great interest as one of the alternatives to conventional chlorination due to its high effectiveness and environmental compatibility. Despite the extensive reports on electro-chlorination disinfection, few researches were reported on the systems without generating chlorine. This study mainly focused on the potential disinfecting ability of electro-generated oxidants other than chlorine with using an inert medium (chloride-free phosphate buffer solution), which was intended to exclude the formation of chlorine during the electrolysis, as the Escherichia coli as an indicator bacterium was disinfected by applying the current to a platinum anode. The electrochemical inactivation of E. coli without chlorine production was demonstrated to occur in two distinct stages. The first stage inactivation takes place rapidly at the beginning of electrolysis, which appears to be achieved by the electrosorption of negatively charged E. coli cells to the anode surface, followed by a direct electron transfer reaction. As the electrolysis continues further, the inactivation becomes slower but steady, in contrast to the first stage of inactivation. This was attributed to the action of reactive oxidants generated from water discharge, such as hydroxyl radical. Overall, this study suggests that the electrochemical disinfection could be successfully performed even without producing chlorine, recommending the potential application for disinfecting water that does not allow including any chloride ions (such as the production of ultra-pure sterilized water for semiconductor washing).     

Evaluation of pressure treated wood impact on landfill waste decomposition using a methane yield assay

Research was conducted to investigate the potential impact of CCA-treated wood and other arsenic-free Cu-based preservative-treated wood on microorganisms, involved in the anaerobic decomposition of waste in landfills. Wood preservatives used included alkaline copper quat (ACQ), copper citrate (CC), copper boron azole (CBA), copper dimethyldithiocarbamate (CDDC), and chromated copper arsenate (CCA). The biochemical methane potential (BMP) assay was used to estimate the possible impacts. The methane yields of mixtures of preservative-treated wood or untreated wood with cellulose (group 1) and these wood samples only (group 2) were determined. An analysis of variance (ANOVA) test found that there were no significant differences among methane yields results in either group 1 or group 2, at the 0.05 level of significance. The results indicate that under the conditions tested, none of the treated wood products evaluated were toxic to the methane-producing organisms. At the end of the assays, test bottle contents were analyzed for Cu, Cr, and As. When the fraction of each metal in the solution (relative to original metal in the wood, leachability %) was examined, As was present at the great extent. The leachability of As was in the range from 15.1% to 21.7% while relatively low leachability (1.7-7.6%) of Cu was observed.     

Sources of fine urban particulate matter in Detroit, MI

Data from the speciation trends network (STN) was used to evaluate the amount and temporal patterns of particulate matter originating from local industrial sources and long-range transport at two sites in Detroit, MI: Allen Park, MI, southwest of both Detroit and the areas of heavy industrial activity; Dearborn, MI, located on the south side of Detroit near the most heavily industrialized region. Using positive matrix factorization (PMF) and comparing source contributions at Allen Park to those in Dearborn, contributions made by local industrial sources (power plants, coke refineries, iron smelting, waste incineration), local area sources (automobile and diesel truck) and long range sources of PM(2.5) can be distinguished in greater Detroit. Overall, the mean mass concentration measured at Dearborn was 19% higher than that measured at Allen Park. The mass at Allen Park was apportioned as: secondary sulfate 31%, secondary nitrate 28%, soil 8%, mixed aged sea and road salts 4%, gasoline 15%, diesel 4%, and biomass burning 3%. At Dearborn the mass was apportioned as: secondary sulfate 25%, secondary nitrate 20%, soil 12%, mixed aged sea and road salts 4%, gasoline 20%, diesel 8%, iron and steel, 5%, and mixed industrial 7%. The impact of the iron and steel, soil, and mixed aged sea and road salt was much higher at the Dearborn site than at the Allen Park site, suggesting that close proximity to a local industrial complex has a direct negative impact on local air quality.