Treatment of bleaching wastewater from pulp paper plants in China using enzymes and coagulants

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Evidence of high organotrophic potentiality of bacteria in the deep ocean

The organotrophic potentiality of heterotrophic microorganisms 50 cm above the ocean floor (5,207 m depth) was measured in situ, at a station in the subarctic Pacific Ocean (44° N; 154° E). In certain enriched deep-sea samples incubated in situ, the microorganisms exhibited nearly the same organotrophic activity as those in the surface water layers. Rod-shaped barophilic bacteria (0.4 to 0.6 μ x 1.0 to 2.0 μ), which multiplied at a generation time of about 10 h, were responsible for this activity.     

Evolutionary significance of prenuptial molting in female <Emphasis Type="Italic">Pagurus</Emphasis> hermit crabs

Molting and breeding entail major energetic costs for female crustaceans. However, females of some hermit crabs perform a molt immediately prior to copulation (prenuptial molt). The evolutionary significance of the prenuptial molt was examined in Pagurus hermit crabs, and two hypotheses were tested: (1) prenuptial molt might enhance the success of the present clutch by cleaning the pleopods of females and thereby preventing eggs from being dislodged from the pleopods, and (2) prenuptial molt might function for growth and increase future fecundity at the cost of energetic expenditure on the present brood. Although these hypotheses are not mutually exclusive, our results rejected the former hypothesis and supported the latter hypothesis. All four Pagurus species examined showed significant negative relationships between prenuptial molting and continuity of breeding; i.e., they showed high molting frequency after they had a long rest period from breeding. Females of P. minutus increased their size through the prenuptial molt, and showed a decreased clutch size due to the molt. The number of dislodged eggs increased if females molted in P. minutus. These results suggest that hermit crabs undergoing a prenuptial molt might not gain any clear immediate advantage of enhanced survival of eggs in the present clutch, and that the prenuptial molt would mainly contribute to growth.     

硅促进水稻种子萌发及缓解幼苗砷毒性的效应研究

通过As~(Ⅲ)胁迫下水稻种子的发芽试验和幼苗毒性试验,研究了外源硅对水稻种子发芽率、幼苗生长的影响及其缓解幼苗砷毒性的效应。外源硅的2种处理方式为种子萌发时添加外源硅(Si1)和采用硅处理液浸种(Si2)。结果表明,发芽时介质中As浓度达到10 mg·L~(-1)时显著抑制水稻种子萌发(P0.05),发芽率仅为80%,但是Si1和Si2处理下发芽率则提高到97%和100%,这说明外源硅可促进砷胁迫下水稻种子萌发;砷浓度≥5 mg·L~(-1)时,Si1和Si2处理均可提高水稻的相对幼苗高度和根耐性指数,提高幅度分别为6.00%~16.8%和57.9%~77.0%、7.10%~23.5%和54.2%~61.2%,并且降低了水稻幼苗砷含量,降低幅度分别为17.8%~21.4%和31.0%~49.1%。这说明外源硅处理可促进砷胁迫下水稻幼苗的生长;不同砷浓度处理与水稻芽长、根长及幼苗干重之间存在"S"型的剂量-效应关系,且外源硅显著提高了相应的EC50,缓解了砷对水稻幼苗生长的毒性。综上所述,砷胁迫下水稻种子萌发时添加外源硅或采用硅处理液浸种均可促进水稻种子萌发和幼苗生长,并降低了幼苗砷累积和缓解砷对水稻幼苗的毒性。     

Development of plastic disks containing flame retardants for elucidating changes in their concentrations due to simulated weathering and the application of these disks to weathering tests

Flame retardants (FRs) are useful because they can prevent combustion and delay the spread of fire after the ignition on commercial products containing plastics. However, such commercial products could be a primary source of environmental contamination with FRs. Plastic disks containing FRs were prepared to elucidate changes in the concentrations of the FRs after weathering tests. Acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) resin were separately kneaded with a combination of three organic FRs [Dechlorane plus (DP), tetrabromobisphenol A (TBBPA), and triphenyl phosphate (TPhP)] and one inorganic FR [antimony trioxide (Sb₂O₃)]. The concentrations of TBBPA/TPhP and DP/Sb₂O₃ in the final preparations were respectively 1000 and 500 mg/kg in compliance with the RoHS directive on organobromine FR. The concentrations of elements in the final preparations were 300 mg/kg for chlorine, 600 mg/kg for bromine, 100 mg/kg for phosphorus, and 400 mg/kg for antimony, respectively. The analytical concentrations (three FRs and four elements) were consistent with the expected concentrations (maximum difference ?9.5% in the PC disks). The FRs and elements in the disks were sufficiently homogenous (maximum inhomogeneity 4.3% in the PC disks). The prepared disks were subjected to weathering tests; the concentrations of TBBPA in the disks decreased significantly (30 to 40%) whereas the concentrations of the elements did not change under the condition of this study. On the other hand, there were no drastic differences on relationships of FRs and elements such as DP/chlorine and TPhP/phosphorus.     

Measuring Sustainability Based Upon Various Perspectives: A Case Study of a Hill Station in Southeast Asia

A hill station is a town or city situated in mountain regions in the tropics founded during the western colonization in the nineteenth and early twentieth centuries. Hill stations have moderate temperatures, and are known for their relatively good natural environments, which generate valuable ecosystem services that benefit the local population. However, rapid urbanization threatens the sustainability of these areas. This study evaluates the sustainability of the urbanization process of Baguio City, a hill station city in Southeast Asia and the summer capital of the Philippines, by determining the relationship between its velocity of urbanization and velocity of urban sustainability based upon various perspectives. From an equal weight perspective (of the triple bottom line of sustainability components, namely environmental, social, and economic) and a pro-economic perspective, the results revealed that the urbanization of Baguio City has been moving toward a “sustainable urbanization.” However, from the environmental and eco-sustainable human development perspectives, the results indicated that it has been moving toward an “unsustainable urbanization.” The paper discusses the implications of the findings for the planning of sustainable development for Baguio City, including some critical challenges in sustainability assessment and the applicability of the framework used for future sustainability assessments of the other hill stations in Southeast Asia.     

Safety management by use of laser mass spectrometry of polychlorinated biphenyls (PCBs) in the processed gas and work environment of a PCB disposal plant

This study demonstrates the applicability of laser mass spectrometry for safety management of the processed gas and the work environment in a polychlorinated biphenyl (PCB) disposal plant. By utilization of laser ionization/ion trapping storage/time-of-flight mass spectrometry (LI-IT-TOFMS), we analyzed gaseous PCBs from scrap capacitors with on-line detection. It was confirmed that few contaminants were detected in the spectrum. By the effect of laser-induced selective ionization, it was considered that there was little interference with the mass range of PCBs. The accuracy of LI-IT-TOFMS when analyzing environmental gas was almost the same as that for the PCB standard gas. It was possible to perform on-line analysis of the work environment for over 2000 h (120 000 data points). LI-IT-TOFMS was thus shown to be a very useful method for ensuring the safety of the work environment in disposal plants for PCBs.     

皮革废水混凝处理实验研究

采用混凝剂对皮革废水进行混凝处理。对3种无机混凝剂和一种有机混凝剂进行了筛选,研究了pH值和投药量对废水中SS、COD、铬和色度等污染物去除效果的影响。结果表明,当pH值在酸性和中性时,效果不明显;当pH值为碱性时,效果显著。硫酸亚铁、硫酸亚铁+PAM和聚合氯化铝(PAC)+PAM 3种混凝剂组合具有良好的混凝效果,在合适的pH值和投药量下,SS和COD的去除率分别达到80%和30%以上,铬和色度的去除率分别达到95%和50%以上。且硫酸亚铁混凝效果好,成本低,适合小型皮革企业需求。