Field validation of an active sampling cartridge as a passive sampler for long-term carbonyl monitoring

A carbonyl sampler originally designed for the active sampling method (Sep-Pak XPoSure) was used for long-term passive sampling, and its applicability as a passive sampler was examined through field experiments. The uptake rates of passive sampling were determined experimentally from collocated passive and active samplings for various sampling periods. The obtained uptake rates of formaldehyde, acetaldehyde, and acetone were 1.48, 1.23, and 1.08 mL/min, respectively. These uptake rates were consistent for a wide range of the sampling term (12 hr-2 weeks). Uptake rates of each carbonyl were proportional to the diffusion coefficients of each. Therefore, the ratios of diffusion coefficients were used to calculate the uptake rates of carbonyls for which the rates were not determined experimentally. Lower limits of determination were 2.16-17.5 microg/m3 for 2-week sampling. It was confirmed that 2-week monitoring of carbonyl concentrations up to 118-229 microg/m3 was possible. Relative standard deviations of the passive method generated from the repeatability test were 2-12.3% error for five samplings, and the recovery efficiencies were larger than 90%. Thus, the passive sampler was found to be highly suitable for long-term monitoring of carbonyl compounds.     

Basic Research on the Emission of Polycyclic Aromatic Hydrocarbons caused by Waste Incineration

The emission of polycyclic aromatic hydrocarbons (PAH) caused by municipal waste incineration varies according to waste composition and operating parameters such as furnace temperature and excess air. However, to obtain a sample sufficient to measure the emission of PAH at trace levels, it is necessary to operate the incinerator for many hours. Since during these lengthy periods it has not always been possible to maintain stable conditions, it is very difficult to determine the relationship between the emission and waste composition.

In our basic research, therefore, we used municipal waste with an artificially regulated composition for our combustion experiments, and by using an experimental Incinerator we examined the emission behavior of PAH with respect to changes in waste composition and combustion conditions. The following facts were revealed by the results: ? The PAH found in the flue gas were predominantly the more volatile compounds.

? When municipal waste was incinerated at over 850 °C, the concentration of PAH in the flue gas increased rapidly as the proportion of plastics in the waste increased from 0 to 24 percent.

? The elimination of plastics from municipal waste by separate collection and the improvement of combustion conditions can effectively diminish the emission of PAH.

     

Biochemical responses in armored catfish (Pterygoplichthys anisitsi) after short-term exposure to diesel oil,pure biodiesel and biodiesel blends

Biodiesel fuel is gradually replacing petroleum-based diesel oil use. Despite the biodiesel being considered friendlier to the environment, little is known about its effects in aquatic organisms. In this work we evaluated whether biodiesel exposure can affect oxidative stress parameters and biotransformation enzymes in armored catfish (Pterygoplichthys anisitsi, Loricariidae), a South American endemic species. Thus, fish were exposed for 2 and 7 d to 0.01 mL L⁻¹ and 0.1 mL L⁻¹ of pure diesel, pure biodiesel (B100) and blends of diesel with 5% (B5) and 20% (B20) biodiesel. Lipid peroxidation (malondialdehyde) levels and the activities of the enzymes glutathione S-transferase, superoxide dismutase, catalase and glutathione peroxidase were measured in liver and gills. Also, DNA damage (8-oxo-7, 8-dihydro-2′-deoxyguanosine) levels in gills and 7-ethoxyresorufin-O-deethylase activity in liver were assessed. Pure diesel, B5 and B20 blends changed most of the enzymes tested and in some cases, B5 and B20 induced a higher enzyme activity than pure diesel. Antioxidant system activation in P. anisitsi was effective to counteract reactive oxygen species effects, since DNA damage and lipid peroxidation levels were maintained at basal levels after all treatments. However, fish gills exposed to B20 and B100 presented increased lipid peroxidation. Despite biodiesel being more biodegradable fuel that emits less greenhouse gases, the increased lipid peroxidation showed that biofuel and its blends also represent hazards to aquatic biota.     

Mass balance and long-term fate of PCDD/Fs in a lagoon sediment and paddy soil, Niigata, Japan

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in a sediment core and in samples of surface sediment and paddy soil collected from the Toyano lagoon and Kameda basin in Niigata, Japan, were analyzed to elucidate the temporal trends of their concentrations in the lagoon sediment and the relationship between the sediment and the paddy soil. The mass balance of these pollutants was also estimated to determine their long-term fate in surface waters. An analysis by chemical mass balance identified the agrochemicals pentachlorophenol and 2,4,6-trichlorophenyl 4-nitrophenyl ether as the major sources of PCDD/Fs. On the basis of the findings regarding the mass balance in the Kameda basin over the last 40 years, we estimate that more than half the input of PCDD/Fs to the Kameda basin has disappeared. We suggest that the PCDD/Fs that flowed out from the paddy fields have been transferred to the lower basin.     

Problems and constraints in Philippine municipal fisheries: The case of San Miguel Bay,Camarines Sur

The Philippine fisheries accounted for 3.7% of the gross national product at current prices. The sector employed about 990,872 persons. Of the divisions comprising the industry, municipal fisheries continued to contribute the largest share of fish production. However, the sector is beset with problems, many of which are best examplified by the case of San Miguel Bay (SMB). This paper presents the problems and constraints confronting SMB, a common property resource. This bay's open access condition has led to various problems, such as declining fishery resources, depressed socioeconomic conditions, illegal fishing, increasing population, and conflict among resource users. A poor marketing system, low level of fishing technology, fishermen's noncompliance and authorities' lax enforcement of rules and regulations, as well as lack of alternative sources of income further characterize the condition in SMB. Establishment of fishing rights, improvement of the marketing system, provision of alternative sources of income, and improvement of fishing technology were some of the solutions suggested. One major constraint, however, is financial, Comanagement complemented with other management tools has been proposed in addressing the problems in SMB.     

Behavior of PCNs, PCDDs, PCDFs, and dioxin-like PCBs in the thermal destruction of wastes containing PCNs

In the first known study to characterize the emissions of polychlorinated naphthalenes (PCNs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) from the thermal treatment of wastes containing PCNs, the formation and decomposition behavior of these pollutants was investigated both at laboratory scale and at plant scale. Exhaust gas measurements from laboratory-scale combustion of rubber belts containing PCNs (FB belts) were used as the basis for calculations predicting that the incremental dioxin toxic equivalency (TEQ) emissions from municipal solid waste (MSW) incinerators would be less than 0.1 ng/m3 N. In order to directly examine co-incineration of FB belts with MSW and to address potential differences between the laboratory experiment and full-scale MSW incinerators, experiments were conducted using a larger scale thermal treatment test facility with sampling and analysis at several points in the thermal treatment process. Congener specific analysis of PCNs clearly showed that both destruction and synthesis simultaneously occurred during combustion in the kiln. Most of the PCNs were destroyed by secondary combustion, and almost all PCNs were removed after flue gas treatment. Almost all PCDDs/DFs were synthesized as by-products of kiln combustion, most of them were destroyed by the secondary combustion, and almost all dioxins (PCDDs/DFs and dl-PCBs) were removed after flue gas treatment. The TEQ emission levels were less than 0.1 ng/m3 N for all plant-scale tests, and differences in TEQ emission levels were very small. Adding wastes containing PCNs to MSW will not influence thermal treatment emissions to the environment from modern solid waste incinerators.     

Bioethanol production from enzymatically saccharified lawn clippings from a golf course

The utilization of bioethanol is being focused on as a fuel alternative to oil and or natural gas. Bioethanol production from cellulosic plant residues is one of the solutions proposed for the problems caused by usage of food crops that are also vital for human consumption, such as sugar cane and corn, as a source of bioethanol. However, to utilize these new sources for bioethanol production, conditions for saccharification in each different material have not been optimized. In this study, we reported some optimum conditions for the saccharification of Korean lawn grass (KL) and bent grass (BG) using acremonium cellulase and endoglucanase as saccharifying enzymes for ethanol fermentation. With respect to saccharification of KL and BG, 0.19 and 0.18 g of d-glucose per g-substrate at maximum were produced, respectively. Comminution with a ball mill was found to be effective in the saccharification of KL, while ball-milled BG showed no significant improvement in saccharification. Being incorporated with 99 % of d-glucose consumption, saccharified KL was incubated for 3 days with Saccharomyces cerevisiae and Zymomonas mobilis, respectively, and each mixture fermented to ethanol yielding approximately 100 % of theoretical values from d-glucose consumption, respectively.     

PCB decomposition and formation in thermal treatment plant equipment

In this study we investigated both the decomposition and unintentional formation of polychlorinated biphenyl congeners during combustion experiments of refuse-derived fuel (RDF) and automobile shredder residue (ASR) at several stages in thermal treatment plant equipment composed of a primary combustion chamber, a secondary combustion chamber, and other equipments for flue gas treatment. In both experiments, the unintentional formation of PCB occurred in the primary combustion chamber at the same time as the decomposition of PCB in input samples. By combusting RDF, non-ortho-PCB predominantly formed, whereas ortho-PCB and symmetric chlorinated biphenyls (e.g., #52/69, #87/108, and #151) tended to be decomposed. ASR formed the higher chlorinated biphenyls more than RDF. These by-products from ASR had no structural relation with ortho-chlorine. Lower chlorinated biphenyls appeared as predominant homologues at the final exit site, while all congeners from lower to higher chlorinated PCB were unintentionally formed as by-products in the primary combustion chamber. This result showed that the flue gas treatment equipments effectively removed higher chlorinated PCB. Input marker congeners of RDF were #11, #39, and #68, while those for ASR were #11, #101, #110/120, and #118. Otherwise, combustion marker congeners of RDF were #13/12, #35, #77, and #126, while those for ASR were #170, #194, #206, and #209. While the concentration of PCB increased significantly in the primary combustion chamber, the value of toxicity equivalency quantity for dioxin-like PCB decreased in the secondary combustion chamber and the flue gas treatment equipments.     

Use of a seeder reactor to manage crystal growth in the fluidized bed reactor for phosphorus recovery.

The authors have been engaged in the development of a phosphorus recovery system capable of maintaining high recovery efficiencies, with the chemical cost suppressed. This time, they conducted demonstration tests of a fluidized bed magnesium ammonium phosphate reactor provided with a seeder reactor for the supernatant from anaerobic digestion using a pilot experimental plant with a wastewater treatment capacity of 20 m3/d. For the digestion supernatant with a phosphorus concentration of approximately 300 mg/L, the treated water phosphorus concentration was 10 to 25 mg/L, and the phosphorus recovery efficiency was more than 90%. Relative to the chemical cost in the case of magnesium chloride, the chemical cost in the case of magnesium hydroxide is approximately 40%. Thus, with the new system, it was possible to reduce the running cost while maintaining high recovery efficiencies.     

Characterization of semi-volatile organic compounds emitted during heating of nitrogen-containing plastics at low temperature

Because of recent volume increases, appropriate management of plastic recycling, which generates various organic compounds, is required to ensure the chemical safety of the processes. The processing temperature and resin type are the important factors determining both the efficiency of the processes and the emission of chemicals. Therefore, we studied the thermal degradation of various plastics at various temperatures from 70 to 300 °C under oxygen-present conditions to identify the semi-volatile organic compounds (SVOCs) emitted and to understand their thermal behaviors. The plastics examined were nitrogen-containing resins, such as polyamide 6, polyurethane, melamine formaldehyde, urea formaldehyde and acrylonitrile-butadiene-styrene. Major commodity plastics were also investigated for comparison. In total, more than 500 SVOCs were detected as emissions from plastics. While various nitrogen-containing SVOCs were detected from nitrogen-containing resins, the major commodity plastics released only these, which possibly were included as additives. These results indicate that the nitrogen atoms in the SVOCs emitted originated from the resins and additives, and not from ambient air at low temperature. As a result of the detection of raw materials, degradation chemicals and by-products of the polymers in the emissions, we found that the variation in chemical species is dependent on the resins. Additives were also emitted from all the resins, meaning that these chemicals were also released to the environment at the temperature examined. In most cases, the numbers and concentrations of SVOCs increased with increasing heating temperature. The variation of thermal behaviors of SVOCs was related to the origins and chemical species of SVOCs.