Effects to perfluorooctane sulfonate (PFOS) on the mollusk Unio ravoisieri under laboratory exposure

To understand acute toxicity and oxidative stress of perfluorinated compounds in the freshwater ecosystems, we exposed freshwater mussels (Unio ravoisieri) to perfluorooctane sulfonate (PFOS), over a range of concentrations from 10 to 100?mg/L, in a laboratory experiment. Lethal concentration (LC50) was of about 65.9?mg/L after 96?h of exposure. The oxidative stress was assessed in gill and digestive gland of the freshwater mussels after 7 days of exposure to different nominal PFOS concentrations (C1=?2?mg/L, C2?=?6?mg/L and C3=?10?mg/L). C1 and C2 increased significantly (p?<?.05) the superoxide dismutase activity in both tissues compared, while the highest C3 decreased the enzyme activity. This implements an unfavourable response that highlights the excess of reactive oxygen species produced after contamination. The Catalase activity was also increased by about 40.05% and 66.63%, respectively, in gill and digestive gland after exposure to C3. The Malondialdehyde (MDA) level was increased in both gill and digestive gland in a concentration-dependent pattern. In contrast, the contamination of U. ravoisieri by PFOS did not affect the acetylcholinesterase activity in both organs (p?>?.005). These results provided information on potential biomarkers that could be effectively applied for the monitoring of freshwater ecosystem using indicator species such as U. ravoisieri.     

Multivariate Statistics of the Pyrolysis Products of High Molecular Components in Pulping Wastewaters to Explain Their Toxicity (6 pp)

Background, Aim and Scope At present, large-scale paper manufacture involves delignification and bleaching by elemental chlorine free (ECF) or totally chlorine free (TCF) processes. The wastewater is purified by secondary treatment (mechanical, chemical and biological) which removes most of the toxic substances from the discharge. However, we found residual toxicity in the high molecular (> 1000 D) matter (HMWM) of the discharge by test of the RET (reverse electronic transfer) inhibition. This fraction consists mainly of polydisperse lignin (LIG) and carbohydrate (CH) macromolecules. Structural units in these molecules are studied by pyrolysis gas chromatography / mass spectrometry (Pyr-GC/MS). In the present work, our aim was to find out those structural units which could explain the RET toxicity of LIG or CH molecules. We compared statistically RET toxicity values of the HMWM samples from treated wastewaters of pilot pulping experiments and intensity variation of the pyrolysis product gas chromatograms of these samples. This application is a novel study procedure. Methods Pyrolysis products (Py-GC/MS results) and inhibition of RET (reverse electronic transport toxicity) as TU50 and TU20 of HMWM (High Molecular Weight Material; Mw > 1000 D) were compared by multivariate statistics. The samples were from laboratory pilot stages of TCF (Totally Chlorine Free) and ECF (Elemental Chlorine Free) manufacture of softwood pulp. Py-GC/MS was done without and with addition of TMAH (Tetra Methyl Ammonium Hydroxide). The name and structure of each abundant fragment compound was identified from its retention time and mass spectrum compared to authentic reference compounds or literature. Four sets of Toxicity Units (TUs) and GC peak areas of the pyrolysis fragments were obtained. The data were normalized by division with LIG (lignin content of each sample). TU values were dependent and the fragment values independent (explanatory) variables in statistical treatments by SPSS system. Separate analyses of correlations, principal components (PCA) and stepwise multiple linear regression (SMLR) were performed from the four sample sets TCF and ECF with and without TMAH. Results and Discussion From the CH fragments, 2-furfural in TCF, and from the LIG fragments, styrene in ECF showed the highest probabilities to originate from source structures of toxicity. Other possible compounds in concern were indicated to be CH fragment 2-methyl-2-cyclopenten-1-one in ECF and LIG fragments 2-methoxy-4-methylphenol, 4,5-dimethoxy-2-methylphenol and 2-methylphenol in TCF.     

Informing global environmental policy‐making: A plea for new methods of assessment and synthesis

Practice and research in assessment of global environmental change are dominated by two conventional assessment methods, formal models and expert panels. Models construct a representation of biophysical and socioeconomic components of a policy issue, to project future trends or consequences of interventions. Panels articulate consensus views of policyrelevant knowledge through deliberations among selected experts. These methods make valuable contributions, but are weak in addressing certain kinds of knowledge needs that are typical of globalchange issues. To address these needs, a set of novel assessment methods is proposed that combine elements of representation and deliberation. These methods, of which policy exercises, simulationgaming, and scenario exercises are examples, involve human participants in structured relevant decision and task settings. Relative to models and panels, these methods can more readily incorporate diverse perspectives, can integrate across broader collections of knowledge domains, and can both encourage creative insights and innovations, and provide tests of their relevance and practicality. Risks of bias, and of overconfident generalization from unique experiences, are effectively mitigated by critical debriefings, and appear no more severe than corresponding risks in conventional assessment methods, or in policymakers generalizations from historical experience. While serious development and implementation challenges remain, early experience suggests that these methods can offer useful ideas and insights for policymaking that are not available through other means.     

ZL50装载机的噪声源识别及降噪处理

采用频谱分析法和相干函数法，利用2230型精密声级计和HP3562动态信号分析仪，对ZL50装载机的噪声进行测试和信号分析，提出了进一步降噪的建议。     

苯并[α]芘对海洋微藻生长及细胞特征的影响

采用急性毒性实验方法,研究了苯并[α]芘(B[α]P)对3种海洋微藻生长和细胞特征的影响。结果表明,B[α]P对3种海洋微藻生长的抑制呈显著的时间-剂量效应,其96 h半数效应浓度依次为:湛江等鞭金藻17.00μg/L,塔溪堤等鞭金藻25.18μg/L,牟氏角毛藻83.06μg/L。高浓度B[α]P胁迫96 h后,3种海洋微藻细胞体积和细胞内容物颗粒均有增加,而藻细胞叶绿素含量却随着B[α]P浓度的增加而降低。这一研究说明,B[α]P对微藻细胞形态及光合能力均能造成明显影响,并可抑制藻细胞数量的增长。B[α]P对藻细胞的抑制作用存在种的差异性,相对来说,金藻类微藻对B[α]P更为敏感。     

垃圾焚烧飞灰浸出液中重金属对藻类的毒性

采用斜生栅列藻、月牙藻、四尾栅藻作为生物指示物,用静水式急性毒性实验监测方法,测试了3种城市固体垃圾焚烧飞灰浸出液fMSwFAL）的重金属抑制藻类生长的毒性。结果表明：当pH值为5和8时,同一受试物具有相差不大的急性毒性：同一藻类,受试物的毒性顺序为：MSWFALⅠ〉MSWFALⅢ〉MSWFALⅡ;不同的藻类,对同一种受试物表现出的敏感性顺序为：月芽藻〉四尾栅藻〉斜生栅列藻。进而对各个受试物的毒性机理进行分析。     

咪唑类ILs对天然水体中斜生栅藻的毒性效应

以生物监测方法,利用国际标准指示性生物斜生栅藻研究了六种咪唑类离子液体的毒性效应,得出了这几种离子液体对自然水体中斜生栅藻96h的半数影响浓度,并初步讨论了待测物的结构和性质对毒性效应的影响。实验结果表明:当固定一取代基为甲基时,咪唑类离子液体对斜生栅藻的抑制作用随着另一烷基取代链长度的增加而加强;而当固定阳离子不变时,发现阴离子所表现出来的对斜生栅藻的抑制作用并不是很明显。     

MBR与A／O工艺处理低温高盐废水的对比试验研究

就MBR和A／O工艺对高盐废水（50％海水）进行处理效果试验研究,比较了氨氮及总氮去除率随温度的变化情况。试验结果表明：低温条件下MBR与A／O工艺经过长期驯化能够稳定运行且获得较高的去除率;随温度从25qC降低到15℃、9℃、5℃时,MBR工艺的COD去除率从81．6％变化到79％、81．1％、82．7％,A／O工艺的COD去除率从67．9％变化到66．6％、65．5％、78．4％。MBR工艺的氨氮去除率从75％变化到68．3％、57．8％、54．6％,A／O工艺的氨氮去除率从70．4％变化到55．9％、49．2％、48．9％,可见COD受温度变化的影响要比氨氮受温度变化的影响小,但经过一段时间的驯化之后,去除效果逐渐变好,并且MBR工艺比A／O工艺受温度变化的冲击要小,处理效果也相对较好。     

利用概率单位法估算EC50的研究（Estimation of Probit Methods on EC50）

以两组典型毒性数据为例,综合比较了5种常见概率单位模型计算程序在EC50估算上的差异,并在此基础上比较了3种不同置信区间的估算方法.在对照组受抑制率为零时,5种方法的参数估算结果一致;当对照组受抑制率不为零时,将对照组数据纳入整个计算过程的方法可以给出可靠的参数估算结果.3种不同置信区间估算方法的比较表明:在毒性数据分布对称性良好的情况下,基于Delta函数与Fieller定理的方法给出的结果相近,但后者可以在更广泛的情况下给出置信区间;相比而言,基于bootstrap重抽样的非参数方法获得的置信区间较窄,表现出更好的灵敏度.     

不同油类对虾蟹类幼体的胁迫效应

了解不同油类对虾蟹类幼体的急性毒性效应。曝油处理采用磁力搅拌器搅拌,一定时间的超声波乳化等操作,模拟溢油在海洋中风浪、涡动、湍流的乳化过程;设置阶梯浓度组,并在多个平行组急性试验的基础上,估算出8种油品对2种虾类和2种蟹类的半致死质量浓度LC50和安全质量浓度MPC,并运用程序编制溢油质量浓度与虾蟹类死亡率相关性的估算模型。经过分析,结果得到:各MPC值参差不齐,差距较大;燃料油普遍比原油的毒性效应大;相同生长阶段,蟹类比虾类抗油毒害性强、中国明对虾Fenneropenaeus chinensis比日本囊对虾Marsupenaeus japonicus抗油毒害性强、锯缘青蟹Scylla serrata比三疣梭子蟹Portunus trituberculatu抗油毒害性强。编制的溢油质量浓度与死亡率相关性的评估模型,简易方便直观,为渔业污染事故理赔提供了一定的参考价值,亦为海域的生态经济学评估提供了一种新的研究方法。