Size partitioning of particulate inorganic nitrogen species between the fine and coarse mode ranges and its implication to their deposition on the surface ocean

In order to discuss the dry deposition fluxes of atmospheric fixed nitrogen species, observations of aerosol chemistry including nitrate (NO₃^?) and ammonium (NH₄⁺) were conducted at two islands, Rishiri Island and Sado Island, over the Sea of Japan. Although the atmospheric concentrations of particulate NH₄⁺–N showed higher values than those of particulate NO₃^?–N at both sites, the dry deposition fluxes of the particulate NO₃^?–N were estimated to be higher than those of the particulate NH₄⁺–N. This was caused by the difference of particle sizes between the particulate NO₃^? and NH₄⁺; NH₄⁺ was almost totally contained in fine particles (d < 2.5 μm) with smaller deposition velocity, whereas NO₃^? was mainly contained in coarse particles (d > 2.5 μm) with greater deposition velocity. Fine mode NO₃^? was strongly associated with fine mode sea-salt and mineral particles, of which higher concentrations shifted the size of particulate NO₃^? toward the fine mode range. This size shift would decrease the dry deposition flux of the fixed nitrogen species on coastal waters and accelerate atmospheric transport of them to the remote oceanic areas.     

Effect of ZnCl<Subscript>2</Subscript> impregnation ratio on pore structure of activated carbons prepared from cattle manure compost: application of N<Subscript>2</Subscript> adsorption-desorption isotherms

Activated carbons were prepared from cattle manure compost (CMC) by ZnCl₂ activation with various ZnCl₂/CMC mass ratios. Based on the N₂ adsorption-desorption isotherms, mathematical models including the Dubinin-Radushkevich (DR) equation, the α_s plot, and the Horvath-Kawazoe method were used to analyze the pore structural characteristics of the prepared activated carbons. It was found that for carbons possessing both micro-and mesopores, the DR method provided a more accurate estimation than the α_s method for the extent of microporosity. The effect of the ZnCl₂ impregnation ratio on the pore structure was discussed using the DR method. The results revealed that pore evolution involved three distinct regions with increases in the amount of impregnated ZnCl₂: raising the ZnCl₂/CMC mass ratio from 0.00 to 0.50 resulted in a 19-fold increase in micropore volume (V_me ^D) but caused no change in the mesopore volume (V_me ^D); increasing the ZnCl₂/CMC mass ratio from 0.50 to 1.00 led to an increment in V_mi ^D of about 50% and in V_me ^D of 170%; while raising the ratio from 1.50 to 2.50 caused a slight decrease in V_mi ^D but a 200% increment in the value of V_me ^D.     

Effect of limited aeration on the anaerobic treatment of evaporator condensate from a sulfite pulp mill

Serious inhibition was found in the regular up-flow anaerobic sludge blanket (UASB) reactor in treating the evaporator condensate from a sulfite pulp mill, which contained high strength sulfur compounds. After applying the direct limited aeration in the UASB, the inhibition was alleviated gradually and the activity of the microorganisms was recovered. The COD removal rate increased from 40% to 80% at the organic loading rate of 8kgCODm(-3)d(-1) and a hydraulic retention time of 12h. Limited aeration caused no oxygen inhibition to the anaerobic microorganisms but instigated sulfide oxidization and H(2)S removal, which was beneficial to the methanogens. The experiment confirmed the feasibility of applying limited aeration in the anaerobic reactor to alleviate the sulfide inhibition. It also proved that the anaerobic system was actually aerotolerant. SEM observation showed that the predominant microorganisms partly changed from rod-shaped methanogens to cocci after the UASB reactor was aerated.     

黑龙江省公路雪冰基本特征与灾害防治对策

黑龙江省冬季降雪不多,但在寒冷和强风条件下,容易产生风吹雪,使某些地点形成较深的积雪,阻塞交通.风吹堆积下的积雪在低温下形成密实坚硬的硬深霜.涎流冰是冬季影响山区交通的另一个主要因素,它的各个部位呈现出间歇性增厚的特征,是涌出水在各处反复交替流动、冻结的结果.随着经济发展,交通流量增加,正常降雪将会产生越来越大的影响和危害,必须给予足够的重视.因此,在雪冰减灾战略对策上,应逐步推广使用防滑汽车轮胎,建立较为完善的公路雪冰清除服务体系,并辅以必要的工程措施.     

Material flows of end-of-life home appliances in Japan

In Japan, the Law for the Recycling of Specified Kinds of Home Appliances came into effect in April 2001. This law aims to introduce appropriate waste treatment and promote the efficient use of resources so that we can achieve a sound material-cycle society. The law introduces a new framework for recycling that places obligations principally on the manufacturers and retailers of home appliances. Material flow analysis of this new framework is essential for evaluation of the system and for finding any problems that may exist. We therefore analyzed the material flows in facilities that recycle electrical home appliances. The mass balances in the recycling facilities were appropriately estimated. Then the potential destinations were surveyed and analyzed, even though the legal framework does not include flows after the recycling facilities. The potential destination after the facilities varies and depends on both the economy and the related regulations. Currently, considerable amounts of recovered materials are exported and recycled. However, the sustainability of these trades is unknown. Therefore, we should keep a close eye on the situation and make sure that our recycling system is adaptable to meet any future changes.     

Identifying a breeding habitat of a critically endangered fish, <Emphasis Type="Italic">Acheilognathus typus</Emphasis>, in a natural river in Japan

Freshwater biodiversity has been severely threatened in recent years, and to conserve endangered species, their distribution and breeding habitats need to be clarified. However, identifying breeding sites in a large area is generally difficult. Here, by combining the emerging environmental DNA (eDNA) analysis with subsequent traditional collection surveys, we successfully identified a breeding habitat for the critically endangered freshwater fish Acheilognathus typus in the mainstream of Omono River in Akita Prefecture, Japan, which is one of the original habitats of this species. Based on DNA cytochrome B sequences of A. typus and closely related species, we developed species-specific primers and a probe that were used in real-time PCR for detecting A. typus eDNA. After verifying the specificity and applicability of the primers and probe on water samples from known artificial habitats, eDNA analysis was applied to water samples collected at 99 sites along Omono River. Two of the samples were positive for A. typus eDNA, and thus, small fixed nets and bottle traps were set out to capture adult fish and verify egg deposition in bivalves (the preferred breeding substrate for A. typus) in the corresponding regions. Mature female and male individuals and bivalves containing laid eggs were collected at one of the eDNA-positive sites. This was the first record of adult A. typus in Omono River in 11 years. This study highlights the value of eDNA analysis to guide conventional monitoring surveys and shows that combining both methods can provide important information on breeding sites that is essential for species’ conservation.     

Empirical research on diffusion behavior of leaked gas in the ground

Chemical plants and gas utilities own large underground pipelines to transport material such as combustible gas. For example, city gas utilities in Japan have about 230,000 km of pipelines, even if only the pipelines to deliver gas to their customers are considered. Any accidents involving such pipelines can lead to enormous human and physical damage, and their security is therefore a top-priority issue for utilities. For the safety management of underground pipelines, in addition to assessment of the long-term reliability of pipeline materials, it is extremely important to understand the diffusion behavior of gases in the ground, such as the diffusion range and time, in the case of leakage, and the impact on the surrounding area is a fundamental factor to be considered in the design and maintenance of safe facilities and for emergency response. Although many papers introduce the situations of gas diffusion in the atmosphere such as indoor and outdoor conditions, only fundamental surveys have been conducted on gas diffusion in the ground, and there have been few full-scale empirical studies. This study reports the results of the verification of the diffusion behavior with full-scale gas leakage experiments simulating real underground pipelines, as well as the outcomes of the applicability test of a numerical simulation model investigated and proposed based on the results. This technical knowledge regarding security will contribute to further improvement of safety in the industry.     

Area-specific temporal changes of species composition and species-specific range shifts in rocky-shore mollusks associated with warming Kuroshio Current

Increases of low-latitude species in various sea areas and poleward shifts of ranges of many species have been reported and linked to warming environments. To examine the generality of these trends for mollusks, we conducted 7 quadrat surveys during 1978–2006 on Pacific rocky shores in Japan (26.6–45.0°N). Results showed that the dominance of southern species increased on 11 of the 15 shores in a southern, warming sea area but on only 1 of the 6 shores in a northern area with no warming trend. The latitudes of species ranges increased on average but showed large interspecific variations which showed a weak, positive correlation with interspecific taxonomic distance. The differences of these results from the previously reported trends are discussed in relation to the unique current patterns in our study area and the phylogenetic constraints of species-specific responses to a warming environment.     

(137)Cs concentration in zooplankton and its relation to taxonomic composition in the western North Pacific Ocean

To study the role of zooplankton in the transport of (137)Cs in the ocean, zooplankton samples were collected in October 2005 and June 2006 in the western North Pacific Ocean. The peak zooplankton biomass was observed in the surface layer, and gelatinous plankton was more abundant in October 2005 than in June 2006 reflecting exchange of water masses. The concentrations of (137)Cs in zooplankton varied from 11 to 24 mBq kg wet(-1) and were higher in October 2005 than in June 2006. The elevated abundance of gelatinous zooplankton probably led to higher concentration of (137)Cs in zooplankton in October 2005. Annual export fluxes of (137)Cs by ontogenetic vertical migrant copepods were estimated to be 0.8 and 0.6 mBq m(-2) year(-1) at 200 and 1000 m depths, respectively; this suggested that transport of (137)Cs by zooplankton may be no trivial pathway.