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.     

Extraction and cleanup methods of dioxins in house dust from two cities in Japan using accelerated solvent extraction and a disposable multi-layer silica-gel cartridge

A simple and rapid method for the extraction and cleanup of dioxins from house dust was developed using an accelerated solvent extraction (ASE) method and a multi-layer silica-gel cartridge. It was found that the WHO-TEQ levels of dioxins extracted from the house dust obtained by both a conventional soxhlet extraction and the ASE were almost equal, when the data obtained by both methods were compared. As for the cleanup method, a multi-layer silica-gel cartridge yielded higher dioxin recoveries than the alkaline digestion method. The average values of the dioxins in house dust from Kumagaya city and Sendai city in Japan (Sendai city is bigger than Kumagaya city with respect to the population and industry), were 15.6 pg TEQ/g (8.6-26.0 pg TEQ/g, n=5, Kumagaya city) and 16.0 pg TEQ/g (5.9-30.5 pg TEQ/g, n=5, Sendai city), respectively.     

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.     

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.     

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.     

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.     

Damage to structures due to liquefaction in the Japan Sea earthquake of 1983

A strong earthquake of magnitude of 7.7 hit the northeast part of Japan on 26th May 1983. Because 100 persons were killed by tsunami, the disaster created a sensation throughout Japan, but there was also a large amount of damage to structures due to the earthquake. Highways, railways, bridges, harbours, levees and private houses were damaged severely in Aomori and Akita prefectures. A great portion of the damage was caused by liquefaction of sand.
This is a prompt report of earthquake damage to structures due to liquefaction. The paper describes general aspects of the damage to structures, with some typical examples are mentioned in more detail. Preliminary results of investigation after the earthquake are also presented to describe the liquefaction phenomena in the earthquake.