Transesterification of soybean oil catalyzed by combusted oyster shell, which is waste material from shellfish farms, was examined. Powdered oyster shell combusted at a temperature above 700 degrees C, at which point the calcium carbonate of oyster shell transformed to calcium oxide, acted as a catalyst in the transesterification of soybean oil. On the basis of factorial design, the reaction conditions of catalyst concentration and reaction time were optimized in terms of the fatty acid methyl ester concentration expressed as biodiesel purity. Under the optimized reaction conditions of a catalyst concentration and reaction time of 25wt.%. and 5h, respectively, the biodiesel yield, expressed relative to the amount of soybean oil poured into the reaction vial, was more than 70% with high biodiesel purity. These results indicate oyster shell waste combusted at high temperature can be reused in biodiesel production as a catalyst.

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Distributions, seasonal variation, flux and contamination source of pesticides and nonylphenol were examined during the period from April 2001 to January 2002 at 5 sites (Namitakiji, Tokumasa-Kami, Izumi, Ochiai and Hinotsume) in Kurose River water, Higashi-Hiroshima, Japan. Water samples were collected monthly and subjected to solid phase extraction followed by GC-MS analysis. Nineteen pesticide compounds were detected and isoprothiolane (37 ng/l), fenitrothion (35) and iprodione (34) showed the highest mean concentrations (as 5 site averages), while pencycuron (5), diazinon (6), tolclofos-methyl (7) and dithiopyr (8) were the compounds of lowest mean concentrations. Nonylphenol, which is a degradation product of a nonylphenolpolyethoxylates that are used in a wide range of industrial and household products, had an average concentration of 305 ng/l. At each of the five sites, its concentration was greater than individual pesticides. The concentration levels of pesticides and nonylphenol were highest at Izumi (the downtown site of Higashi-Hiroshima) and were lowest at Namitakiji and Tokumasa-Kami (upstream sites). Concentrations and fluxes of both compounds tended to be higher during spring to summer and low during fall to winter at most of the sites. The total pesticides concentration was poorly correlated with nonylphenol concentration. A statistical analysis of water quality data suggested that their main sources appear to be different such as agricultural activity for pesticides and waste water discharge for nonylphenol.

The simultaneous spectrophotometric determination of phosphate and silicate ions in river water was examined by using ion-exclusion chromatography and post-column derivatization. Phosphate and silicate ions were separated by the ion-exclusion column packed with a polymethacrylate-based weakly acidic cation-exchange resin in the H(+)-form (TSKgel Super IC-A/C) by using ultra pure water as an eluent. After the post-column derivatization with molybdate and ascorbic acid, so-called molybdenum-blue, both ions were determined simultaneously by spectrophotometry. The effects of sulfuric acid, sodium molybdate and ascorbic acid concentrations and reaction coil length, which have relation to form the reduced complexes of molybdate and ions, on the detector response for phosphate and silicate ions were investigated. Under the optimized conditions (color-forming reactant, 50 mM sulfuric acid-10 mM sodium molybdate; reducing agent, 50 mM ascorbic acid; reaction coil length, 6 m), the calibration curves of phosphate and silicate ions were linear in the range of 50-2000 microg L(-1) as P and 250-10,000 microg L(-1) as Si. This method was successfully applied to water quality monitoring of Kurose-river watershed and it suggested that the effluent from a biological sewage treatment plant was significant source of phosphate ion in Kurose-river water.

Polycyclic aromatic hydrocarbons (PAHs) have been widely studied with respect to their carcinogenic and mutagenic effects on animals and human cells. Phenanthrene (PHE) and fluoranthene (FLU) effects on the needle photosynthetic traits of 2-year-old Japanese red pine (Pinus densiflora Sieb. et. Zucc.) seedlings were investigated. Three months after fumigation of foliage with solutions containing these PAHs (10 microM each), FLU had negative effects on net photosynthesis at near-saturating irradiance, stomatal conductance, initial chlorophyll fluorescence, and the contents of total chlorophyll, magnesium, and ribulose 1,5-bisphosphate carboxylase (rubisco) of current-year needles. PHE had similar negative effects to FLU but in lesser magnitude. The effects of the PAHs were mitigated by the addition of an OH-radical scavenger (mannitol) into the PAH solutions. PAHs deposited on the surface of pine needles may induce the generation of reactive oxygen species in the photosynthetic apparatus, a manner closely resembling the action of the herbicide paraquat.