我国地方层面生态补偿实践经验与借鉴

生态补偿机制的构建,不仅有利于缩小区际间的差距,还原生态以价值,而且还是环境降压的出口,促进环境建设,走可持续发展的道路。文章以生态补偿实践应用的角度为切入点,从流域、省域和地市3个层面系统分析了地方生态补偿的实践经验,在此基础上提出了现有的实践经验对我国地方层面生态补偿所带来的借鉴与启示。     

A市产业部门碳排放分布结构及影响因素研究

本研究在对A市碳排放现状进行分析的基础上,分析了A市碳排放产业分布结构和A市碳排放的驱动因素,并根据分析的结果提出A市实现节能减排目标的政策建议。     

北京1o个常绿树种颗粒物吸附能力研究

大气中颗粒物PM( particuIate matter)不仅造成环境污染,还对人体造成严重的危害.城市绿色植物作为大气过滤器,能够有效地提高城市空气质量,保护人体健康.因此了解不同树种对空气颗粒物的吸附滞纳作用是必要的.以北京植物园10种常绿植被为研究对象,应用空气气溶胶再发生器( QRJZFSQ_I)测定了北京市常见6种乔木和4种灌木叶片对空气总悬浮颗粒物( TSP)﹑PM10﹑PM2.5和PM1.0的吸附能力.结果表明①不同树种叶片表面附着颗粒物的能力差异明显,最高的是雪松( Cedrus deodara)和油松( pinus tabuliformis),吸附量分别是(18.95±0.71)μg.cm-2和(14.61±0.78)μg.cm-2,冷杉( Abies fabri)最小,为(8.02±0.4)μg.cm-2;②不同树种叶片单位面积对不同颗粒物的附着能力也存在差异,附着PM10能力最强的是油松和雪松,附着PM2.5能力最强的是雪松﹑铺地柏( Juniperus procumbens)﹑龙柏( Juniperus chinensis cv. kaizuka)和油松,附着PM1.0能力最强的是雪松﹑铺地柏﹑冷杉和油松;③不同月份叶片上附着的各粒级颗粒物( PM10﹑ PM2.5 )占TSP的比例不同.其中PM10在4~6月之间主要表现两种变化趋势,一是先上升后下降,主要为灌木树种;二是逐渐上升,主要的树种是乔木树种.而PM2.5则没有这种明显的变化趋势.     

砒砂岩修复晋陕蒙能源区铅污染土壤的研究

寻找合适的材料来修复晋陕蒙地区因煤炭、石油和天然气开发导致的土壤重金属污染是该区域环境治理的重要措施.砒砂岩具有较强的吸附性,是可以用于土壤重金属污染修复的潜在材料.本研究通过室内模拟实验来研究土壤中添加砒砂岩对铅形态分布、毒性溶出量(TCLP)的影响及其对土壤孔隙度、pH、田间持水量、土壤酶活性的影响.结果表明,砒砂岩可显著降低土壤弱酸提取态铅含量,增加可还原态与残渣态铅含量;随土壤中砒砂岩添加量的增加,高活性态铅的降幅越大低活性态铅的增幅越大.砒砂岩显著降低了土壤铅毒性溶出量,降低程度与砒砂岩添加量成正比.砒砂岩的较强吸附特性及可以提高土壤pH是固化土壤重金属铅的重要因素.此外,砒砂岩对土壤理化性质的改善一定程度上对污染土壤起着改良作用.     

珠江水体中细菌碱性磷酸酶基因phoD的多样性

碱性磷酸酶(APase)是最主要的有机磷水解酶,在无机磷匮乏的情况下,APase释放的无机磷供藻类利用,致使藻类大量繁殖,因此,对APase基因多样性的研究有利于揭示对水体富营养化有重要影响的微生物类群.基于此,本文以珠江水体为研究对象,构建了珠江广州段穗石、坦尾和南沙3个点细菌的pho D基因克隆文库.限制性酶切片段多态性(RFLP)分析结果表明,上述3个点的pho D基因分别含有15、17、13个操作分类单元(Operational Taxa Unit,OTU),穗石点的多样性(Shannon指数和Simpson指数)均高于其他两个点;pho D基因序列系统发育分析表明,珠江水体中pho D基因主要来源于Plesiocystis、Limnohabitans、Pirellula等属的细菌,而Limnohabitans属的pho D基因在文库中含量最高,占文库的44%~50%.研究表明,珠江水体中细菌的pho D基因具有较高的多样性,这些基因编码的碱性磷酸酶可能在珠江水体的富营养化过程中有重要的作用.     

下击暴流的三维仿真和回波特征分析

下击暴流产生的强风切变对飞机的飞行和起降危害严重,为避免其对飞行的危害,需充分认识下击暴流的气流结构特征。该文利用特征风场建模方法,仿真了下击暴流的三维结构。通过设置风场的特征半径、扭曲因子、风场中心位置及上限高度,仿真对称与不对称的切变风场。对仿真的三维风场沿雷达径向投影,得到下击暴流的雷达径向速度。通过分析下击暴流的三维空间结构和对应的雷达回波特征,验证了仿真风场的结构与实际观测相吻合。研究结果表明,对下击暴流的雷达回波分析,有利于飞行员对下击暴流的识别和预警,有助于保障飞行安全。     

A kinetic study of Mn(II) precipitation of leached aqueous solution from electrolytic manganese residues

Electrolytic manganese residue (EMR) is a type of solid waste discharged from the process that converts solid manganese carbonate of rhodochrosite into soluble Mn(II) and generates anode mud under electrolysis. The experimental material was a filtrate created by using distilled water as a dispersal agent for the EMR, followed by simple filtration. A calculated amount of sodium carbonate was added to recover the soluble Mn(II) via precipitation into manganese carbonate. Data showed that Mn concentration may be markedly decreased from 2069 to 36 mg/L, thereby reaching a recovery rate as high as 98%. Analysis demonstrated that precipitation of Mn(II) from a leached aqueous solution followed first-order kinetics. The findings indicate that the reaction rate constant decreased as temperature gradually rose and that its apparent activation energy E_a was ?10.48 kJ/mol.     

全氟辛烷磺酸钾(PFOS)和纳米氧化锌(Nano-ZnO)单独与联合暴露对斑马鱼胚胎的氧化损伤和细胞凋亡的影响

探讨全氟辛烷磺酸钾(PFOS)和纳米氧化锌(Nano-Zn O)复合暴露对斑马鱼机体氧化损伤和细胞凋亡的影响。将斑马鱼胚胎暴露于PFOS(0、0.4、0.8和1.6 mg·L-1)、Nano-Zn O(0、12.5、25和50 mg·L-1)、PFOS+Nano-Zn O(0、0.4+12.5、0.8+25和1.6+50 mg·L-1)溶液中6天后,检测相关的酶活性变化(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(Gpx)、脂质过氧化物(MDA)、半胱氨酸蛋白酶(Caspase-3和Caspase-9)和与细胞凋亡相关基因(Bax,p53和Bcl-2)表达情况。结果表明:PFOS和Nano-Zn O单独与复合暴露均可造成斑马鱼胚胎的氧化损伤和细胞凋亡,但复合暴露组的氧化损伤和细胞凋亡程度明显大于单独暴露组。在PFOS和Nano-Zn O单独和复合暴露组中,随着处理浓度的升高,SOD、Gpx、Caspase-3和Caspase-9酶的活性显著升高。而CAT酶活性随着处理浓度的升高抑制作用显著。PFOS与Nano-Zn O复合暴露组与单独暴露组相比,Bax和p53表达显著上调,而Bcl-2表达显著下调。因此,在实验浓度范围内,等毒性配比1:1条件下,推测NanoZn O可以增强PFOS对斑马鱼胚胎的氧化损伤和细胞凋亡毒性。     

The potential risk assessment for different arsenic species in the aquatic environment

The different toxicity characteristics of arsenic species result in discrepant ecological risk. The predicted no-effect concentrations (PNECs) 43.65, 250.18, and 2.00 × 10³ μg/L were calculated for As(III), As(V), and dimethylarsinic acid in aqueous phase, respectively. With these PNECs, the ecological risk from arsenic species in Pearl River Delta in China and Kwabrafo stream in Ghana was evaluated. It was found that the risk from As(III) and As(V) in the samples from Pearl River Delta was low, while much high in Kwabrafo stream. This study implies that ecological risk of arsenic should be evaluated basing on its species.     

Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human-hamster hybrid cells

Microcystin-LR (MC-LR) is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen (Group 2B) by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human-hamster hybrid (A_L) cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher (p < 0.01) in A_L cells exposed to a cytotoxic concentration (1 μmol/L) of MC-LR for 30 days than in untreated control cells, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide (NO) production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor N^G-methyl-_L-arginine (L-NMMA), which suppressed MC-LRinduced mutations as well. The survival of mitochondrial DNA-depleted (ρ⁰) A_L cells was markedly decreased by MC-LR treatment compared to that in A_L cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.