Influence of microorganisms on the behavior of technetium and other elements in paddy soil surface water

Insolubilization patterns of technetium (Tc) and other trace elements (Sc, Co, Zn, Se, Rb, Sr, Y, Nb, Ce, Pm, Gd, Lu, Hf, and Re) in surface water covering paddy fields were compared to gain insight into the behavior of Tc in an agricultural environment. The insolubilization of Tc, which did not pass through a 0.2-microm-pore-size filter, was mainly caused by bacteria. Among the 14 other elements investigated, Nb was insolubilized by bacteria and the amounts of insoluble Nb were positively correlated with those of Tc. Although Re is a chemical analog of Tc, no similarity was observed. These results suggest that Tc behaves similarly to Nb in the insolubilization in surface water covering paddy fields.     

The influence of paddy soil drying on Tc insolubilization by bacteria

Tc insolubilization in four soils samples was compared by pre-incubating them in both dry and wet states, then measuring Tc concentrations in solution when the samples were saturated with an excess of water spiked with 99Tc. Soils pre-incubated in a dry state showed higher Tc insolubilization than soils incubated in a wet state. To clarify the difference in Tc insolubilization, Eh, bacterial abundances, and bacterial species compositions in the dry and wet ponding water samples were determined. For the wet ponding water samples, Eh values were forced to decrease, but no increase in Tc insolubilization was observed. The dry and wet ponding water samples had similar numbers of bacteria. However, denaturing gradient gel electrophoresis analysis revealed that they had different bacterial species compositions. These results suggested the difference in bacterial species compositions would account for the difference in Tc insolubilization.     

Cooperative web sharing against predators promotes group living in spider mites

I examined spider mite cooperative web sharing against predation as a factor promoting group living. Tetranychus urticae and Tetranychus kanzawai infest leaf surfaces under webs made of silk threads. Experimental observation of predation by the predatory mite Euseius sojaensis on spider mites of different group sizes revealed that fewer spider mites were preyed upon when the web-building period before the attack was prolonged, suggesting that established webs help protect spider mites. Moreover, per capita predation on spider mites was diluted in larger groups. This was not due to predator satiation but seemingly because webs had been completed while the initial prey was consumed. Spider mites lived more closely together in the presence of a predator, showing that the degree of group living is facultative. In the presence of a preceding spider mite with an established web, a newcomer spider mite gain protection by taking residence in the established webs; sharing the web was not disadvantageous for the preceding mite. The proportion of individuals preyed upon did not differ between preceding and newcomer mites, suggesting that there was no interference against the latter. These interactions were consistent between heterospecific spider mites. Because there was no detectable indirect interaction between mites sharing fresh webs, cooperative web sharing seemed to be a major force promoting group living in the spider mites. Moreover, the distances between spider mites did not differ between heterospecific and conspecific groups, demonstrating that mites living together do not distinguish between species; hence, heterospecific mites may cooperate and live together in the same manner as conspecifics.     

Gasification and smelting system using oxygen blowing for plastic waste including polyvinyl chloride

A new type of waste gasification and smelting system using oxygen blowing based on high-temperature metallurgy, was developed by Sumitomo Metals, Japan. This system can steadily gasify and melt not only municipal waste, but also plastic waste and polyvinyl chloride (PVC) waste by using a top-blow oxygen lance together with sideways-blow oxygen lances. As a result of gasification in the high-temperature reducing atmosphere and rapid gas cooling, dioxin-free, high-calorie purified gas was produced. Ash components in the wastes were smelted in a high-temperature reducing atmosphere, and high-quality slag free of heavy metals was produced. Most of the chlorine in the wastes was converted into hydrogen chloride in the off gas. The hydrogen chloride can be recovered as hydrochloric acid or chlorine, which are recyclable to PVC manufacturing.     

Novel malonate-type copolymers containing vinyl alcohol blocks as biodegradable segments and their builder performance in detergent formulations

Poly[(disodium methylene malonate)-co-(vinyl alcohol)] [P(DSMM-VA)] and poly[(disodium ethoxymethylene malonate)-co-(vinyl alcohol)] [P(DSEMM-VA)] containing a poly(vinyl alcohol) (PVA) block as a biodegradable segment were prepared and their biodegradability and functionality were evaluated and compared with those of the corresponding fumarate and maleate copolymers. It was found that the 1,1-dicarboxylate-type copolymers, P(DSMM-VA) and P(DSEMM-VA), showed better biodegradability than the corresponding 1,2-dicarboxylate-type copolymers, P(DSF-VA) and P(DSM-VA). This improved biodegradability of P(DSMM-VA) and P(DSEMM-VA) is probably attributable to their more expanded polymer chain in aqueous solution, which will be more accessible to the degrading enzymes. The minimum chain length of the PVA-block, which acts as a biodegradable segment in the polymer chain, is estimated to be 2–3 and 3–4 monomer units for P(DSMM-VA) and P(DSEMM-VA), respectively. On the other hand, the minimum PVA block is about 5 and 7 monomer units for the fumarate and maleate copolymers, respectively. It was confirmed that P(DSMM-VA) showed excellent builder performance compared to the corresponding fumarate copolymer.Paper presented at the Bio/Environmentally Degradable Polymer Society—Second National Meeting, August 19–21, 1993, Chicago, Illinois.     

Motivation of Japanese companies to take environmental action to reduce their greenhouse gas emissions: an econometric analysis

To analyze the motivations of Japanese companies to take environmental actions to reduce their greenhouse gas (GHG) emissions, we used FY2006 research data and questioned Japanese industries regarding their reduction of GHG emissions. Empirical investigations revealed that voluntary targets set by industry organizations, government requirements, and advance responses to possible future regulations can positively influence environmental actions for GHG emission reduction; however, cost reductions and corporate social responsibility fulfillment cannot.

Biodegradable water-soluble polycarboxylic acid design: Biodegradability and builder performance in detergent formulation of partially dicarboxylated polyuronide containing sugar residues in the backbone

Partially dicarboxylated polyuronide having a variable amount of unreacted sugar blocks as an enzymatically cleavable segment was prepared by the controlled oxidation of pectic acid and alginic acid. It was found that partially dicarboxylated polyuronides containing uronide blocks showed better biodegradability than those having no uronide block in the polycarboxylate chain. The rate of biodegradation varies according to the degree of dicarboxylation. It was confirmed that dicarboxy polyuronides containing more than 70% unreacted uronide residues tended to biodegrade quickly. The biodegradability obtained by the BOD test and the enzymatic degradability are well correlated, suggesting that these polymers are first cleaved at the sugar blocks by carbohydrase with subsequent assimilation of the resultant oligomeric fractions. Detergency was dependent on the content of the carboxylate groups in the polymer. The polymers with high carboxylate contents showed better builder performance. The detergency of dicarboxy pectic acid was better than that of dicarboxy alginic acid when compared on the basis of an equal degree of dicarboxylation.     

Plant origin of Okinawan propolis: honeybee behavior observation and phytochemical analysis

Propolis is a natural resinous product collected by honeybees from certain plants. It has gained popularity as a food and alternative medicine. Poplar and Baccharis are well known as the source plants of European and Brazilian propolis, respectively. However, the propolis from Okinawa, Japan, contains some prenylflavonoids not seen in other regions such as Europe and Brazil, suggesting that the plant origin of Okinawan propolis is a particular plant that grows in Okinawa. To identify the plant origin of Okinawan propolis, we observed the behavior of honeybees as they collected material from plants and caulked it inside the hive. Honeybees scraped resinous material from the surface of plant fruits of Macaranga tanarius and brought it back to their hive to use it as propolis. We collected samples of the plant and propolis, and compared their constituents by high-performance liquid chromatography with a photo-diode array detector. We also compared their 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity. The chemical constituents and biological activity of the ethanol extracts of the plant did not differ from those of propolis. This indicates directly that the plant origin of Okinawan propolis is M. tanarius. S. K. and J. N. contributed equally to this work.     

The dynamics of mercury around an artisanal and small-scale gold mining area,Camarines Norte,Philippines

Environmental Science and Pollution Research - To elucidate the dynamics of mercury emitted and released by artisanal and small-scale gold mining (ASGM) activity and to estimate its impact on the...     

Comparison effect of feedstock to inoculum ratios on biogas yields of cafeteria,vegetable, fruit wastes with cattle manure using co-digestion process

Cafeteria, vegetable, fruit, and cattle manure are available year around at low cost and have the potential to complement each other for anaerobic digestion (AD). The objectives of this study were to determine the preferred mixing ratios and effects of feedstock to inoculum ratios for the optimal biogas production. The mesophilic digestion tests were performed with five mixing ratios of CW, VW, FW with CM and five feedstock to inoculum (F/I) ratios using batch anaerobic digesters. Co-digestion of CW, VW, FW with CM was carried out at F/I ratios of 1.0, 2.0, 3.0, 4.0, and 5.0. The results showed that the F/I ratio significantly affected the biogas production rate. Increasing the CW, VW, FW in the CM resulted in an increased methane yield by decreasing the F/I ratios in the reactors from 5.0 to 1.0. The highest biogas yields of 591.3, 432.9, and 450.6 L/kg VS_feed were obtained with CW/CM (50:50), VW/CM (25:75), and FW/CM (25:75) ratios, respectively. At five F/Is tested, after 45 days of AD, the total biogas yields were determined to be 629.74, 552.64, 501.87, 464.66, and 396.04 L and 496.93, 460.02, 420.5, 398.14, and 336.20 L, and 455.03, 382.81, 349.78, 340.95, and 298.53 L, respectively. However, the highest average CH₄ contents obtained at an F/I of 1.0 were 62.14%, 60.72%, and 61.08% that are 5.87%, 9.47%, and 10.17% higher than those obtained at F/I ratio of 5.0 for CW/CM (50:50), VW/CM (25:75), and FW/CM (25:75), respectively.