施加盐基离子调控水稻Cd的吸收与累积

盐基离子含量是土壤肥力的重要指标,也是决定土壤Cd生物有效性的重要因素.为探明盐基离子对稻田系统中Cd迁移、转运与累积的影响,本研究通过水稻盆栽试验,按照土壤中盐基离子的物质的量比施加不同浓度梯度KCl、CaCl_2、NaCl和MgCl_2到模拟制备的轻度(0.5 mg·kg~(-1))和中度(1.5 mg·kg~(-1))Cd污染土壤,分析盐基离子对土壤CaCl_2提取态Cd含量和水稻吸收累积Cd的影响.结果表明:施加盐基离子能够增加土壤阳离子交换量(CEC),在轻度和中度Cd污染土壤中,土壤CaCl_2提取态Cd含量分别下降了24.6%～56.1%和17.0%～71.1%,糙米Cd含量分别降低了9.1%～60.5%和7.2%～36.0%.在轻度和中度Cd污染土壤中,糙米Cd含量与土壤CaCl_2提取态Cd含量之间存在线性正相关关系,根、茎、叶Cd含量与Ca含量均呈线性负相关.     

环胶州湾河流入海口CDOM吸收光谱特征

为深入认识河流对胶州湾水体有机碳的贡献,于2016年4月-2017年2月对环胶州湾河流入海口进行双月采样,通过分析水体中DOC（溶解有机碳）和POC（颗粒有机碳）质量浓度及CDOM（有色溶解有机物）的吸收光谱特征,揭示环胶州湾入海口有机碳的分布特征,辨析CDOM的组成和来源,探讨其与主要环境因素的关系.结果表明:①环胶州湾河流入海口DOC和POC质量浓度范围分别为0.98~32.75和0.13~22.40 mg/L,其中李村河口最高,轮渡和大港相对较小.②a（355）（CDOM的吸收系数）变化范围为0.23~16.35 m-1,存在明显的季节性差异,与盐度成反比,其分布与DOC和POC基本一致.③研究区域水体中,表征CDOM分子组成、来源及芳香化程度的S_R[光谱斜率比,S_g（275~295 nm）/S_g（350~400 nm）]和A_{250 nm}/A_{365 nm}存在显著的时空差异.④夏季、秋季CDOM的整体分子量水平高于春季、冬季;轮渡、大港、板桥坊河和娄山河S_R相对较高,CDOM组成趋向于蛋白类或富里酸类物质.⑤轮渡、大港和镰湾河A_{250 nm}/A_{365 nm}相对较高,类腐殖质的芳香化程度较低,受海源控制;其他河口A_{250 nm}/A_{365 nm}相对较低,CDOM以陆源输入为主,其类腐殖质的芳香化程度较高,结构相对稳定而不易降解.⑥CCA（Canonical Correspond Analysis,典范对应分析）结果表明,DOC与CDOM吸收特性存在较好的相关性,河口CDOM主要来自地表径流,温度和DO是影响CDOM时空分布的主要因素.研究显示,CDOM的组成、降解的难易程度与来源密切相关,秋季生物量丰富,水体中腐殖酸所占比例增大,CDOM芳香度较高,不容易被降解.      

广东省土壤镉含量影响因子解析与评估

影响镉(Cd)含量的因子众多,包括自然影响因子和人为影响因子,而治理Cd污染首先应查明Cd污染来源及其影响因子,这对因地制宜制定Cd污染治理措施及指导相关产业布局具有重要意义.广东省地理状况复杂、经济发达,Cd含量分布区域间差异较大.因此,本文基于Cubist构建土壤Cd含量与相关影响因子关系模型,解析影响广东省土壤Cd含量的主要因子.结果表明:土壤pH值与土壤类型是影响广东省Cd含量最主要的因素,土壤Cd含量与土壤pH值呈正相关关系;赤红壤、砖红壤及紫色土中Cd含量相对较低,潮土、红壤、黄壤、水稻土及石灰土中Cd含量相对较高.Cd含量高值主要出现在第四纪、泥盆纪和石炭纪地质构造运动形成的土壤中.此外,植被指数、土壤粉粒、平均气温、高程、距道路及距河流距离也是影响广东省土壤Cd含量的主要因素.其中,土壤Cd含量与土壤粉粒、高程呈正相关关系,与植被指数、距道路距离、距河流距离呈负相关关系.本文研究结果可为土壤Cd污染治理提供科学的参考依据.     

Plot-scale spatiotemporal variations of CO2 concentration and flux across water–air interfaces at aquaculture shrimp ponds in a subtropical estuary

Human activities have increased anthropogenic CO₂ emissions, which are believed to play important roles in global warming. The spatiotemporal variations of CO₂ concentration and flux at fine spatial scales in aquaculture ponds remain unclear, particularly in China, the country with the largest aquaculture. In this study, the plot-scale spatiotemporal variations of water CO₂ concentration and flux, both within and among ponds, were researched in shrimp ponds in Shanyutan Wetland, Min River Estuary, Southeast China. The average water CO₂ concentration and flux across the water–air interface in the shrimp ponds over the shrimp farming period varied from 22.79?±?0.54 to 186.66?±?8.71 μmol L^?1 and from ??0.50?±?0.04 to 2.87?±?0.78 mol m^?2 day^?1, respectively. There was no remarkable difference in CO₂ concentration and flux within the ponds, but significantly spatiotemporal differences in CO₂ flux were observed between shrimp ponds. Chlorophyll a, pH, salinity, air temperature, and morphometry were the important factors driving the spatiotemporal patterns of CO₂ flux in the shrimp ponds. Our findings highlighted the importance and spatiotemporal variations of CO₂ flux in the important coastal ecosystems.

     

台北市生活垃圾管理经验及启示

台北市生活垃圾管理效果显著,人均生活垃圾日清运量年均减量7.3%、资源回收率年均增长28.3%并带动资源回收产业发展、居民负担仅为1998年的22.0%、社会成本较1998年减少30.7%。主要经验包括:明确的生活垃圾减量与资源回收目标;系统的管理模式设计,包括政府(环保局、地方清洁队、资源回收管理基金)、生产商、回收商、处理商、居民、垃圾焚烧厂和填埋场以及第三方等主要干系人。采取的主要政策手段包括强制源头分类、随袋征收垃圾处理费、建立资源回收管理基金、对资源回收行业的政策扶持以及信息公开与公众参与等。台北市先进的生活垃圾管理经验对中国大陆城市开展垃圾分类与资源化管理具有重要的参考价值。     

Performance and microbial diversity of an expanded granular sludge bed reactor for high sulfate and nitrate waste brine treatment

The disposal of waste brines has become a major challenge that hinders the wide application of ion- exchange resins in the water industry in recent decades. In this study, high sulfate removal efficiency （80%-90%） was achieved at the influent sulfate concentration of 3600 mg/L and 3% NaC1 after 145 days in an expanded granular sludge bed （EGSB） reactor. Furthermore, the feasibility of treating synthetic waste brine containing high levels of sulfate and nitrate was investigated in a single EGSB reactor during an operation period of 261 days. The highest nitrate and sulfate loading rate reached 6.38 and 5.78 kg/（m3-day） at SO42--S/NO3-N mass ratio of 4/3, and the corresponding removal efficiency was 99.97% and 82.26% at 3% NaC1, respectively. Meanwhile, 454-pyrosequencing technology was used to analyze the bacterial diversity of the sludge on the 240th day for stable operation of phase X. Results showed that a total of 9194 sequences were obtained, which could be affiliated to 14 phyla, including Proteobacteria, Firmicutes, Chlorobi, Bacteroidetes, Synergistetes and so on. Proteobacteria （77.66%） was the dominant microbial population, followed by Firmicutes （12.23%） and Chlorobi （2.71%）.     

五氯酚对土壤跳虫代谢转化酶基因和蜕皮相关基因表达的影响

五氯酚(PCP)是一种广泛存在于环境中的有机污染物。利用土壤跳虫(Folsomia candida)作为受试生物,研究了不同浓度的PCP暴露下细胞色素P450(CYP450)基因、谷胱甘肽转移酶(GST)基因和蜕皮相关基因表达水平的变化。结果显示,PCP暴露下,跳虫CYP450基因Fcc01651、Fcc02155、Fcc03650和GST基因Fcc04073、Fcc05260的表达水平未发生显著变化。在PCP浓度为240 mg·kg-1时,跳虫GST基因Fcc00494的表达显著上调。在PCP浓度为120 mg·kg-1和240 mg·kg-1时,几丁质酶基因Fcc00881和几丁质结合域基因Fcc01306的表达受到显著抑制。研究结果可为评价PCP暴露对跳虫的毒性提供一定依据。     

Study on substrate metabolism process of saline waste sludge and its biological hydrogen production potential

With the increasing of high saline waste sludge production, the treatment and utilization of saline waste sludge attracted more and more attention. In this study, the biological hydrogen production from saline waste sludge after heating pretreatment was studied. The substrate metabolism process at different salinity condition was analyzed by the changes of soluble chemical oxygen demand (SCOD), carbohydrate and protein in extracellular polymeric substances (EPS), and dissolved organic matters (DOM). The excitation-emission matrix (EEM) with fluorescence regional integration (FRI) was also used to investigate the effect of salinity on EPS and DOM composition during hydrogen fermentation. The highest hydrogen yield of 23.6 mL H₂/g VSS and hydrogen content of 77.6% were obtained at 0.0% salinity condition. The salinity could influence the hydrogen production and substrate metabolism of waste sludge.

     

NO oxidation over Co-La catalysts and NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> reduction in compact SCR

A series of Co-La catalysts were prepared using the wet impregnation method and the synthesis of catalysts were modified by controlling pH with the addition of ammonium hydroxide or oxalic solution. All the catalysts were systematically investigated for NO oxidation and SO₂ resistance in a fixed bed reactor and were characterized by Brunanuer–Emmett–Teller (BET) method, Fourier Transform infrared spectroscopy (FTIR), X–ray diffraction (XRD), Thermogravimetric (TG) and Ion Chromatography (IC). Among the catalysts, the one synthesized at pH = 1 exhibited the maximum NO conversion of 43% at 180°C. The activity of the catalyst was significantly suppressed by the existence of SO₂ (300 ppm) at 220°C. Deactivation may have been associated with the generation of cobalt sulfate, and the SO₂ adsorption quantity of the catalyst might also have effected sulfur resistance. In the case of the compact selective catalytic reduction (SCR), the activity increased from 74% to 91% at the highest gas hourly space velocity (GHSV) of 300000 h^–1 when the NO catalyst maintained the highest activity, in excess of 50% more than that of the standard SCR.

Open image in new window

     

Estimating the heterogeneous and dynamic economic impacts of China’s energy consumption control policy

Environmental Science and Pollution Research - In the late stages of its industrialization, China’s economy still largely relies on energy. With increasing pressures to protect the...