震动强度对反倾层状岩质边坡动力响应规律的影响

通过振动台模型试验探讨震动强度对反倾层状岩质边坡动力响应规律的影响,着重分析边坡加速度响应峰值、加速度放大系数随震动强度增加的变化规律。结果表明:①随着震动强度增加,模型边坡各测点的加速度响应峰值不断增大,地震波频率和测点位置影响加速度响应峰值的增加方式;②震动强度对模型边坡各测点加速度放大系数的影响因地震波频率、测点位置的不同而有不同的表现。同一频率地震波作用下,相同高程的测点加速度放大系数随震动强度增加的变化规律相同;③0.20g是边坡变形破坏的临界加速度值;④震动强度的变化并不改变加速度响应峰值、加速度放大系数在边坡中的分布。该研究结果对高地震区的地质灾害防治具有指导和借鉴-意义。     

Preliminary investigation on cytotoxicity of fluorinated polymer nanoparticles

As well-known persistent organic pollutants(POPs), organofluorine pollutants such as perfluorooctane sulfonate(PFOS) have been proven to be bioaccumulated and harmful to health. However, toxicological assessment of organofluorinated nanoparticles, which have emerged as a novel tool for biomedical and industrial applications, is lacking, to the best of our knowledge. To assess the biological effects and health risk of fluorinated nanoparticles,trifluoroethyl aryl ether-based fluorinated poly(methyl methacrylate) nanoparticles(PTFEPMMA NPs) were synthesized with various fluorine contents(PTFE-PMMA-1 NPs 12.0 wt.%,PTFE-PMMA-2 NPs 6.1 wt.% and PTFE-PMMA-3 NPs 5.0 wt.%), and their cytotoxicity was investigated in this study. The in vitro experimental results indicated that the cytotoxicity of PTFE-PMMA NPs was mild, and was closely related to their fluorine(F) contents and Fcontaining side chains. Specifically, the cytotoxicity of PTFE-PMMA NPs decreased with increasing F content and F-containing side chains. After exposure to PTFE-PMMA NPs at a sublethal dose(50 μg/m L) for 24 hr, the phospholipid bilayer was damaged, accompanied by increasing permeability of the cell membrane. Meanwhile, the intracellular accumulation of reactive oxygen species(ROS) occurred, resulting in the increase of DNA damage, cell cycle arrest and cell death. Overall, the PTFE-PMMA NPs were found to be relatively safe compared with typical engineered nanomaterials(ENMs), such as silver nanoparticles and graphene oxide, for biomedical and industrial applications.     

酸雨的危害及其防治综述

从酸雨的研究历史出发,阐述了酸雨的形成和分布,指出酸雨是一种全球性的环境问题;酸雨对生态系统、人类健康、材料等都具有很大危害.通过对近几年我国酸雨状况调查,分析发现我国酸雨面积和程度呈现继续扩大的趋势.最后,结合我国典型的硫酸型酸雨特征,提出了可行的防治酸雨的具体对策.     

湿地公园的植物景观设计——以上海崇明岛西沙湿地公园为例

湿地公园是湿地与公园的复合体,体现了“在保护中利用,在利用中保护”的生态思想,其中植物景观起到了很大的作用。在湿地公园的设计中,对湿地植物的选择也尤为重要。上海崇明西沙湿地公园,是一个以自然保护为主的主体性公园。其保留了大部分的水生植物和湿生植物的构建模式,在保留层面有很大的优势,但同时也体现出一定的不足,希望通过对其优劣势的分析,对今后的湿地植物景观设计有更多的借鉴。     

水分管理对重金属在水稻根区及在水稻中积累的影响

选取了酸性矿山废水污灌区重金属污染水稻土,通过盆栽试验,研究了不同水分管理条件（60%最大田间持水量,80%最大田间持水量,最大田间持水量,前期淹水＋抽穗扬花期烤田,全生育期淹水）下水稻根际土壤及其不同器官（稻根、茎叶和籽粒）中As、Cd、Cu和Zn的含量变化。结果表明：土壤水分含量对水稻根际土壤中As、Cu和Zn的含量影响不大。但显著影响水稻不同器官对这3种元素的吸收积累。随着土壤水分含量的增加,水稻根、茎叶和籽粒中As的含量都显著增加;Cu的含量则逐渐减少;水稻茎叶中Zn含量也逐渐减少,但水稻根和籽粒中Zn含量则变化不明显。抽穗扬花期拷田能显著降低As在水稻中的积累,显著增加水稻茎叶中Zn的积累;但不影响水稻各器官中Cu,以及水稻根和籽粒中Zn的含量。此外,虽然这3种重金属在土壤中含量均超标,但在水稻籽粒中含量只有Zn全部超标,而Cu则都不超标,因此,农作物的超标情况并不直接与土壤的重金属超标相联系。     

不同磷肥对棕壤吸附铜的影响

采用等温平衡法研究3种性质不同的磷肥（磷酸二铵,钙镁磷肥和磷矿粉）对棕壤铜吸附量的影响,并应用Freundlich方程Cs=KfCen分析土壤铜的吸附特征。结果表明,与不施磷肥处理（对照）相比,当n（磷）：n（铜）=1：1时,钙镁磷肥和磷矿粉增加棕壤对铜的吸附量,分别增加107%和158%;不同用量的磷酸二铵均会降低棕壤对铜的吸附能力;增加非水溶性磷肥（钙镁磷肥和磷矿粉）的施用量,能增加棕壤对铜的吸附量,提高棕壤的吸附能力;高量磷矿粉的作用效果最为明显。由此可知,为降低农产品质量安全风险,铜污染棕壤上不宜施用磷酸二铵,但可选用磷矿粉作为肥源。     

估算多氯联苯在鱼体中生物富集因子的片段常数法

根据４０种ＰＣＢ的实测数据建立了估算ＰＣＢ在鱼体中生物富集系数的片段常数模型,建模化合物的ｌｇＢＣＦ在２．６５－５．９７之间,ｌｇＫｏｗ则在３．８８－８．１８之间,由于特定氯取代位的影响以及在此Ｋｏｗ范围内ＢＣＦ与化合物憎水性之间的非线性关系,简单的片段常数模型不能有效估算ＢＣＦ。     

硅肥施用对重金属污染土壤甘蔗镉吸收的影响研究初探

长期采用受铁矿尾矿水污染的河水进行灌溉的农田,其土壤存在一定重金属镉污染,且土壤酸化严重,有效硅活性低。甘蔗是需硅量较大的植物,因此在甘蔗种植过程中施用碱性硅肥既可补充硅营养又可通过硅肥控制镉的吸收。本试验通过硅肥不同施用量及基肥、基肥＋追肥的施用方式的比较,结果表明：在甘蔗种植中一次性施用硅肥1500 kg·hm-2,可以使土壤中活性较高的弱酸提取态镉占镉总量的比例从38.45%下降到32.51%,而甘蔗不能利用的残渣态镉的占比从11.19%提高到14.78%;硅肥分为基肥与追肥两次施用的方式,其对土壤镉的形态的影响也存在相似的规律,且变化趋势更加显著,弱酸提取态镉占比从40.93%下降到35.47%,降幅更加显著;同样残渣态镉则随着硅肥施用量的增加而增加,其占比从16.26%增加到22.66%;施用硅肥能有效降低甘蔗汁中镉的含量,从一次性作为基肥施用的结果来看,每公顷施用375~1500 kg硅肥,其蔗汁中镉含量随施肥量增加而下降,从168.54μg·L-1降至57.87μg·L-1,降幅为28.26%~60.30%;蔗渣中镉含量也有相似的变化趋势,从468.36μg·kg-1降至377.77μg·kg-1,降幅为7.86%~19.34%;采用基肥＋追肥施用硅肥,无论是蔗汁还是蔗渣,其镉的含量同样随硅肥施用量的增加而下降,蔗汁镉含量的降幅更大,最高可降81.18%,从而达到降低甘蔗汁及蔗渣中镉含量水平的目的。     

高硫高铁土壤全硫提取和测定方法的改进

硫酸钡分光光度比浊法是大批量测定土壤环境样品硫含量的常用方法,但影响测定结果的因素较多,如稳定剂的选择、酸度的控制、BaCl：的形态和用量等均可对测定结果产生影响。在多金属硫化物矿区,由于长期的采矿冶炼活动,造成周边土壤中硫、铁含量增加,用比浊法测定硫含量时,铁的含量也对测定结果产生显著影响。针对这些影响因素,本研究在用硝酸．高氯酸湿法对土壤进行消解后,优化了硫酸钡分光光度比浊法测定高硫高铁样品的实验条件和实验步骤,并对多金属硫化物矿区的土壤样品进行了测定,得到了较好的结果。实验证明,称取0．50g土壤样品,消解后过滤,取滤液7mL,加入1mL研（1＋2）甘油．乙醇]=6％的甘油．乙醇为稳定剂,1mL浓磷酸掩蔽Fe3＋与cl-反应所显的黄色,定容到10mL,加入w（BaCl2）=10％的氯化钡溶液10mL,电磁搅拌1min,静置20-40min,在波长440nm处,比浊法测定土壤全硫含量,相对误差〈10％,取得良好的测定结果。此方法简单、快捷、方便,适合大批量环境样品的测定。     

Pelagic-benthic coupling of the microbial food web modifies nutrient cycles along a cascade-dammed river

• Structure of multi-trophic microbial groups were analyzed using DNA metabarcoding. • Discontinuity and trophic interactions were observed along the dam-fragmented river. • C, N and P cycles are driven by top-down and bottom-up forces of microbial food web. • Pelagic-benthic coupling may intensify nutrient accumulation in the river system. Cascade dams disrupt the river continuum, altering hydrology, biodiversity and nutrient flux. Describing the diversity of multi-trophic microbiota and assessing microbial contributions to the ecosystem processes are prerequisites for the restoration of these aquatic systems. This study investigated the microbial food web structure along a cascade-dammed river, paying special attention to the multi-trophic relationships and the potential role of pelagic-benthic coupling in nutrient cycles. Our results revealed the discontinuity in bacterial and eukaryotic community composition, functional group proportion, as well as α-diversity due to fragmentation by damming. The high microbial dissimilarity along the river, with the total multi-trophic β-diversity was 0.84, was almost completely caused by species replacement. Synchronization among trophic levels suggests potential interactions of the pelagic and the benthic groups, of which the β-diversities were primarily influenced by geographic and environmental factors, respectively. Dam-induced environmental variations, especially hydrological and nutrient variables, potentially influence the microbial food web via both top-down and bottom-up forces. We proposed that the cycles of carbon, nitrogen and phosphorus are influenced by multi-trophic groups through autotrophic and heterotrophic processes, predator–prey relationships, as well as the release of nutrients mainly by microfauna. Our results advance the notion that pelagic-benthic trophic coupling may intensify the accumulation of organic carbon, ammonium and inorganic phosphorus, thereby changing the biogeochemical patterns along river systems. As a consequence, researchers should pay more attention to the multi-trophic studies when assessing the environmental impacts, and to provide the necessary guidance for the ecological conservation and restoration of the dam-regulated systems.