Concentration and trend of 9,10-phenanthrenequinone in airborne particulates collected in Nagasaki city, Japan

9,10-Phenanthrenequinone (PQ), one of the components of atmospheric pollutants, has potent harmful effects on human health. PQ in airborne particulates collected in Nagasaki city was determined by HPLC with fluorescence derivatization. PQ extracted from airborne particulates using methanol was derivatized with benzaldehyde in the presence of ammonium acetate to give a fluorescent compound. The average concentration (mean+/-SD, n=52) of PQ found in airborne particulates collected from July 1997 to June 1998 was 0.287+/-0.128 ng m-3. Concentrations of PQ in winter were higher than those in summer. In a weekly variation study, PQ concentrations were higher during weekdays and lower at weekend. The levels of PQ were obviously correlated with those of phenanthrene (PH) that is considered as a parent compound of PQ. This observation suggested that PQ was emitted into the atmosphere from the same source as PH, or PQ was converted from PH in the atmosphere.     

The significance of social capital in local forest management in Laos: Overcoming latent conflict between local people and local forestry officials

Forest policies that devolve forest-use rights to local people have undergone development over the past few years in Laos. As collaboration between local people and forestry officials is seen as indispensable to effective and sustainable local forest management, the objective of this study is to clarify the issues pertinent to the resolution of latent conflict between these two stakeholders. The issues are examined by presenting two case studies in terms of forest management as perceived by local people and forestry officials; the first in a rich forest area and the second in a degraded forest. Issues relating to land and borders and social capital are identified as the most important in the degraded forest area, while social capital is a very important issue in the rich forest area. Our studies show that the problems of land and border issues in the degraded forest area were caused by an inappropriate resettlement policy. This can be interpreted as the mismanagement of social capital, and for effective local forest management it is very important to overcome problems of this nature. The effective use of social capital has so far been overlooked, however, in the establishment of collaborative forest governance at the local level.     

Ecological significance of salp fecal pellets collected by sediment traps in the eastern North Pacific

Five sediment traps were moored at depths of 740, 940, 1 440, 3 440 and 4 240 m for 7 d in December 1982 at Station 5 in the eastern North Pacific about 400 km from San Francisco. Dark green sinking particles enclosed in tough membrane consisted of mostly coccolithophores with some diatoms, dinoflagellates and chrysophytes. The average size of the particles was 10x5x2 mm. These characteristics indicate that the particles were fecal pellets of salp inhabiting the surface waters. Vertical fluxes of the organic carbon and nitrogen through sinking of the salp fecal pellets ranged from 6.7 to 23 mgC m^-2 d^-1 and from 0.88 to 3.2 mgN m^-2 d^-1, respectively. These values were several times higher than those determined in other oceanic areas by sediment trap experiments. Hydrocarbons consisting of short-chain n-alkanes (n-C₁₅-C₂₀) with n-C₁₇, the most predominant component, heneicosa-hexaene (n-C_21:6), br-C₂₅ alkenes and long-chain n-alkanes (n-C₂₁-C₃₀), without any odd or even carbon number predominance, were found from five depths. The presence of short-chain n-alkanes and n-C_21:6 indicated that phytoplankton in the surface waters was a primary source of organic matter in the sinking particles. Two isomers of br-C_25:3 and br-C_25:4 alkenes found in these particles also indicated that br-C₂₅ alkenes were the important biological marker of fecal pellet of zooplankton. The distribution pattern of the long-chain n-alkanes suggested that the sinking particles may be affected by bacteria to some extent. Fatty acids of the sinking particles were separated into free, triglyceride and wax ester fractions consisting of mono- and poly-unsaturated, and saturated fatty acids, with a range from C₁₄ to C₃₀. Concentrations of mono- and poly-unsaturated fatty acids decreased more rapidly toward the deep than those of saturated fatty acids, which cause low ratios of mono- and poly-unsaturated fatty acids/saturated fatty acids. This indicates that unsaturated fatty acids were more rapidly decayed by marine microbes than saturated fatty acids in the deep water, despite the fact that a significant amount of unsaturated fatty acids still remained in the sinking particles collected from the deep waters. Our results revealed that the salp fecal pellet plays an important role in supplying foods to organisms in intermediate and deep seas.     

Woodchip-mixing porous mortar’s adsorption of cesium in aqueous media

Journal of Material Cycles and Waste Management - The radioactive cesium (radio-Cs) released following the Fukushima Daiichi Nuclear Power Plant accident was unevenly distributed in soil, sediment,...     

Methods for selenium removal from contaminated waters: a review

Environmental Chemistry Letters - Worldwide contamination of waters by metals, metalloids, and organometallic pollutants is a major health issue. In particular, the occurrence of the selenium...     

Sensor-based sorting of waste digital devices by CNN-based image recognition using composite images created from mass and 2D/3D appearances

Journal of Material Cycles and Waste Management - To improve the recycling process of waste from electrical products, we developed a sensor-based sorting system using convolutional neural network...