Microbial succession associated with organic matter decomposition during thermophilic composting of organic waste.

Using dog food as a model of the organic waste, thermophilic composting was carried out for 14 days at a fixed temperature of 60 degrees C. The relationship between organic matter decomposition measured by CO2 evolution during the bio-stabilization process and microbial succession expressed as the changes over time in the restriction fragment length polymorphism (RFLP) patterns of 16S rDNA sequences, of micro-organisms associated with the composting material was also examined. The CO2 evolution rate peaked on day 3 and gradually decreased until it became extremely small after day 9 of composting, indicating that vigorous organic matter decomposition ceased around this time. On the other hand, the RFLP pattern changed drastically from day 0 to day 4 or 5, then remained stable until day 7 or 8, reaching its final configuration, with little variations, after day 9 of composting. RFLP analysis therefore indicates that microbial succession continued into the later stage of composting. Nevertheless, by day 9, the rate of organic matter decomposition was so low that its influence on microbial populations could be hardly recognized by conventional methods of dilution plating. Moreover, the compost produced by day 9 showed no inhibitory effect on the growth of Komatsuna (Brassica campestris L. var. rapiferafroug), indicating that the maturity of compost is sufficient for plant growth when the rate of organic matter decomposition has become extremely low and the RFLP patterns become stable.     

Accumulation of endocrine disrupting chemicals (EDCs) in the polychaete Paraprionospio sp. from the Yodo River mouth,Osaka Bay,Japan

This study presents the levels of endocrine disrupting chemicals (EDCs) accumulated by Paraprionospio sp. from the Yodo River mouth, Osaka Bay. Since high concentrations of nonylphenol (NP), bisphenol A (BP), octylphenol (OP), 17β-estradiol (E2), and estrone (E1) have been measured in sediment from Osaka Bay, some bioaccumulation could be expected particularly in benthic animals. EDCs were analysed in Paraprionospio sp., a dominant benthic species in Osaka Bay. The results showed that Paraprionospio sp. had accumulated varying concentrations (wet weight; w.w.) of NP at 1,460–4,410 ng/g; BP at 22.5–39.6 ng/g; OP at 18.9–45.4 ng/g; E2 at 0.89–4.35 ng/g; and E1 at 0.06–2.50 ng/g. Accumulation of NP and OP were highest among the samples gathered in summer (July 2008), while concentrations of BP, E2, and E1 did not much differs within 3 years. EDC levels in Paraprionospio sp. were apparently greater than those in sediments showing bioaccumulation.     

Effects of humic acids derived from lignite and cattle manure on antioxidant enzymatic activities of barley root

To investigate the effects of humic acids (HAs) on the ability of plants to defend themselves against oxidative stress, barley was hydroponically cultured in the absence and presence of HAs, and the antioxidant enzymatic activities (catalase, superoxide dismutase, ascorbate and glutathione peroxidases) of root tissue were evaluated. Auxin-like structures in HAs, which were extracted from an oxidation product of lignite (LHA) and compost derived from cattle manure (CHA), were identified by pyrolysis-gas chromatography/mass spectrometry (GC/MS) with tetramethylammonium hydroxide. The LHA, which had the lower molecular weight, was more effective in promoting the growth of barley root than CHA. However, the amounts of auxin-like structures in the CHA were much higher than those for LHA. The antioxidant enzymatic activities were initially decreased in the presence of LHA and CHA at the first day after refreshing the culture solution, but were significantly increased on the second day. The CHA sample, which contained relatively high levels of phenolic acids that contained auxin-like structures, was effective in increasing four types of enzymatic activities, while the activities of catalase and ascorbate peroxidase were increased in the presence of LHA, which contains naphthalene derivatives. These results indicate that using HAs as a supplement can be effective in enhancing antioxidation enzymatic activities, while the appearance of the effects is retarded because of the decomposition and release of auxin-like compounds from HAs by organic acids from the plant roots.     

Spectroscopic analysis of NIR-dye sensitization in bulk heterojunction polymer solar cells

The photovoltaic conversion efficiency for near-infrared (NIR) sunlight is improved successfully by dye sensitization of bulk heterojunction polymer solar cells, in which the active layer was prepared by a ternary blend of poly(3-hexylthiophene), a fullerene derivative (1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene), and an NIR dye, silicon phthalocyanine bis(trihexylsilyl oxide). The mechanism of the NIR-dye sensitization is studied by femtosecond transient absorption spectroscopy.     

Mass balance of arsenic and antimony in municipal waste incinerators

The arsenic and antimony balance in two municipal waste incinerators was investigated. Initially, the production rates of ash and wet scrubber effluent were estimated. Then the arsenic and antimony in the ash and wet scrubber effluent were determined, which gave an estimate of the elemental balance. The total amounts of arsenic and antimony in the municipal waste were 0.9 g/t and 30–44 g/t, respectively. The distributions to fly ash were 45–47% and 33–74% for arsenic and antimony, respectively. The distribution mechanisms of arsenic and antimony are discussed from the viewpoints of their thermodynamics as well as their initial valencies, which greatly affect their behaviour. Received: July 2, 1998 / Accepted: February 27, 1999     

Measurements of radon around closed uranium mines

There are several waste rock yards at closed uranium mines around Ningyo-toge, in the Western Honshu Island of Japan, and measurements of radon were carried out by both the passive method and the sampling method around these yards. As comparatively high radon concentrations were observed in two districts through routine measurements, more detailed measurements were made by the passive method in these districts. The impact of radon emanation from the waste rock yards was small for both residential districts and around these yards when considering the natural background level of radon. In addition, by simultaneous continuous measurements of radon and its progeny at two locations, it was estimated that the effective dose caused by the representative uranium waste rock yards was less than the public effective dose limit of 1 mSv year(-1) at the fenced boundary of the waste rock site.     

Anthropogenic radionuclides in the Japan Sea: their distributions and transport processes

The anthropogenic radionuclides, (90)Sr, (137)Cs and (239+240)Pu, were measured in the water column of the Japan Sea/East Sea during 1997-2000. The vertical profiles of radionuclide concentrations showed: exponential decrease with depth for (90)Sr and (137)Cs, and surface minimum/subsurface maximum for (239+240)Pu. These results do not differ substantially from results reported previously. The area-averaged concentrations of radionuclides in the Japan Sea are higher than those found in the Northwest Pacific Ocean below surface layer showing the accumulation of the radionuclides in the deep waters in the Japan Sea. Concerning spatial distributions, the area of high (137)Cs inventory extends from the Japan Basin into the Yamato Basin. It is suggested that wintertime convection of water, occurring mainly in the Japan Basin, causes the radionuclides to sink. The nuclides then advect into the Yamato Basin after detouring around the Yamato Rise.     

Cost-effectiveness Analysis of Reducing the Emission of Nitrogen Oxides in Asia

The purpose of this study is to evaluate cost-effective reduction strategies for nitrogen oxides (NO _x ) in the Asian region. The source-receptor relationships of the Lagrangian “puff” model of long-range transportation, ATMOS-N, were used to calculate the wet/dry deposition of the nitrogen (N) in Asia. Critical loads of N deposition in Asia were calculated from the relationships between the critical load of sulfur (S) and balance of N in and out using the data of S critical load of RAINS-ASIA. The cost functions of N reduction of Asian countries were derived by the regression analysis with the data of cost functions of European countries used in RAINS. In order to assess the environmental impact, the gaps between N deposition and critical load of N were calculated. The emission of NO _x was reduced in some cases of this model, and the changes of gaps between N deposition and critical load were observed as well as the changes of the reduction cost. It is shown that a uniform reduction of NO _x emissions by countries in Asia is not cost-effective strategy.     

Mitigation of peroxidative stress for barley exposed to cadmium in the presence of water-extractable organic matter from compost-like materials

The effects of water-extractable organic matter (WEOM) from compost-like materials on peroxidative stress were investigated for hydroponic culture of barley exposed to Cd. In the presence of WEOM, lipoxygenase activity and malondialdehyde, indices of peroxidative stress in barley, were significantly reduced, compared to those with Cd alone (5 μM) for a 30-d culture (p < 0.05). In addition, Cd uptake in the presence of WEOM samples was significantly lower than that in their absence (p < 0.05). These results indicate that the addition of WEOM can be effective in mitigating the peroxidative stress in barley exposed to Cd. Of the total Cd in the solution, 7–8% was complexed with WEOM, indicating that the complexation of Cd with WEOM is a minor factor in reducing Cd-induced stress in barley. The WEOM sample was purified by cation-exchange column and ultrafiltration to remove the nutrient minerals, such as Ca, Mg and Fe. When the purified WEOM was employed for hydroponic culture in the presence of Cd, significant decreases in peroxidative stress and Cd uptake were observed (p < 0.05). These results show that the organic components in WEOM contribute to the mitigation of peroxidative stress in barley exposed to Cd.