Temporal variations of dissolved nitrogen and phosphorus were measured in Hiuchi-Nada and Iyo-Nada in the late spring . In Iyo-Nada, water temperature and salinity stratified, which caused vertical distributions of dissolved inorganic nitrogen and phosphorus (DIN and DIP). Dissolved organic nitrogen and phosphorus (DON and DOP) were superior to DIN and DIP, respectively. Temporal variations of DIN, DIP, DON and DOP were small in Iyo-Nada. In Hiuchi-Nada, the amounts of DIN and DIP were even smaller than those of DON and DOP similar to Iyo-Nada. However, DON and DOP changed dynamically daily in contrast to those in Iyo-Nada . This difference between the two seas could be related to a tidal current which caused the resuspension of deposits on the sea floor in the case of Hiuchi-Nada . These results show that the regional differences are reflected in the temporal variations of DON and DOP and to a limited extent in the temporal variations of DIN and DIP. This suggests the importance of measurements of DON and DOP in view of the nitrogen and phosphorus budgets.

View full abstract

The effect of copper ion added in the medium on the contents of UDP-sugars in a heavy metal tolerant fungus, Penicillium ochro-chloron ATCC 36741, was studied. Cytoplasmic sugar nucleotides were extracted by aqueous perchloric acid from the mycelia cultured both in the basal medium containing 0.1 mg 1-1 copper and in the copper supplemented medium (1 mol l-1). The contents of sugar nucleotides along with the growth stages were compared. In the presence of copper, the HPLC analysis revealed the presence of same sugar nucleotides as in the control culture, whereas the total contents of sugar nucleotides were far less than those of control culture. Among them, UDP-N-acetyl-glucosamine and UDP-glucose were identified as major UDPsugars in the control culture, whereas in the presence of copper, UDP-glucose was a trace in amount while UDP-N-acetylglucosamine remained unchanged. Change of the cell wall composition was discussed in relation to the content of cytoplasmic UDP-sugars.

View full abstract

The atmospheric concentrations of 16 component hydrocarbons were calculated by the Chemical Element Balance (CEB) method adapted the major six source contribution values (best-fit CEB coefficients) of 15 component profiles to those fixed with 16 components (15 components+propylene) . As the results, the large part of the unexplained concentration [(measured) - (CEB calculated) concentration] was due to the high atmospheric concentrations of benzene, toluene and ethylbenzene. An another emission source of these aromatic hydrocarbons than the six those used in this study is indicated to be a wastewater, which is proposed by only a report in USA. The study of wastewater components may be necessary for more detailed CEB calculation of the urban ambient non-methane hydrocarbons in Japan . The relatively large differences were observed between the measured and CEB calculated concentrations of propylene at the general air monitoring stations. While, little difference was observed at the roadsides near to the vehicle emission source. The CEB method in this study may give much information to the atmospheric degradation of high photoreactive hydrocarbon such as propylene.

View full abstract

Electric appliances utilize many toxic elements. They can be legally disposed in a dumping ground. In the case of electric appliances thrown away as a waste, it has not been clear which toxic element in electric appliances would be more eluted under a specified condition. The study of elution behavior of toxic elements in electric appliances under various conditions in of primary importance to understand its effect on the environment. In this work, weight percentages of toxic elements in electric appliances were estimated, and the elution of toxic elements in their components was investigated under conditions of three kinds of pseudo-environments (pure water, salt solution and acid solution). The elution concentration of Pb was the largest among all eluted elements under each condition, and it was especially large under the acid solution. It is probable that Pb elutes to a certain extent from solder and components such as CRT glass under an acidic rain for a long period. It is desirable to establish immediate and concrete techniques for the prevention of the elution of Pb, for instance, the recycling of Pb, the coating on the printed circuit board by an appropriate substance free from toxic elements, the reduction in amount of solder, and the recovery of CRT glass etc.. The elution of Zn, Cu and Sb was also observed, but the elution quantity was not so large as that of Pb.

View full abstract

[in Japanese]

View full abstract

Source apportionment was performed on a small amount of particulates collected in subway platforms and their surroundings . We collected samples on three types of subway stations : a station with well ventilated by the piston movement of trains, a station of the third rail subway system, and a deep station with well air-conditioned. In this study, we used a personal air sampler for 30 minutes-sampling period . Samples were collected at the center of the platform, the ground level near the entrance, and the intermediate level between the entrance and the platform of each station . Two sets of samples were collected on the well ventilated station at different time period daytime and evening rush hour. From the results of the mass concentration measurements, it was clearly shown that the mass concentration of particulates at the platform were higher than others when traffic is heavy. The results of source apportionment showed that more than seven types of sources were detected from each sample. At the platform, 70 percent or more of particles contained Fe as major component, and some of particles were estimated to originated from roadway. At the ground level near the entrance of subway stations, most of particles were estimated to arise from roadway. Particles of Ba5O4 were also detected in samples at the platform and the intermediate site, but not detected in the samples from ground level near the entrance. We can conclude that source apportionment of particulates collected from urban artificial space by this method is effective and practically useful, with a small sample amount.

View full abstract

[in Japanese]

View full abstract

After the Chernobyl accident, high concentrations of radiocesium, ¹³⁷Cs (half-life, 30y) and¹³⁴Cs (half-life, 2.06y), in mushrooms, especially fruit bodies of basidiomycetes, were reported in European forests. In our previous studies we have determined the levels of radiocesium (¹³⁷Cs and ¹³⁴Cs) and also the natural radionuclide ⁴⁰K in Japanese mushrooms (167 samples belonging to 81 species) collected in 1989 and 1990. Median concentration of ¹³⁷Cs was 45 Bq/kg (dry wt), indicating that the radiocesium level in Japanese mushrooms was mush lower than that in Europe. However, ¹³⁷Cs concentrations of more than 1000 Bq/kg (dry wt) were found in some mushroom samples collected in Japanese forests. In continuation of the previous studies, we collected additional 117 mushroom samples in 1991 and analyzed them for ¹³⁷Cs ¹³⁴Cs and ⁴⁰K. This paper presents our new analytical results and summarizes data obtained for mushrooms (284 samples belonging to 124 species) collected during 1989 to 1991. The radiation dose due to the consumption of mushrooms in Japan was also estimated.

View full abstract