巴彦淖尔盟草场资源开发利用中存在的生态环境问题及其对策

巴彦淖尔盟地区草场退化问题已十分严峻 ,本文分析了巴彦淖尔盟草场资源开发利用中存在的生态环境问题及其成因 ,并提出了解决问题的对策     

喜马拉雅山中段北坡地表水体主要离子特征及其控制因素——以叶如藏布流域为例

为调查喜马拉雅山中段北坡地表水环境特征,2015年9月在叶如藏布流域采集24个地表水体水样并对其水化学特征分析测定,研究结果表明:(1)叶如藏布流域水化学特征存在显著空间差异.随着海拔升高,地表水体p H值、TDS值呈微弱的减小趋势.24个水样中23个水样属于淡水,1个为微咸水.(2)叶如藏布流域内地表水阳离子主要为Ca~(2+),阴离子以SO_4~(2-)为主,其次为HCO_3~-,即地表水为Ca~(2+)-SO_4~(2-)型.(3)叶如藏布流域地表水中各离子之间具有不同程度的相关性.其中Cl~-、HCO_3~-、Na~+和K~+4种离子共源性好;阳离子的来源不同,Na~+和K~+主要来源于碳酸氢盐,Ca~(2+)主要来源于硫酸盐,而Mg~(2+)的来源比较广泛.(4)叶如藏布流域大部分离子主要来源于陆地,受陆源影响从小到大排列顺序为:Na~+Mg~(2+)SO_4~(2-)Ca~(2+)K~+HCO_3~-.流域水文化学过程主要受岩石风化作用控制,特别是受到碳酸盐风化影响.以强木村为界,流域下游地区地表水化学特征受人类活动影响逐渐变大,特别是畜牧活动及人类施肥的影响.     

铬离子对藻类生长的影响

利用自然光照条件,在不同铬离子质量浓度下,对5种藻类的生长进行了实验研究.研究结果表明:5种藻类在不同的光波长下,其吸收光谱存在两个最强的吸收区: 420～440 nm的蓝紫光部分和660 nm 的红光部分;在不同铬离子质量浓度0～20.63 mg·L-1范围内,5种藻类生长受到不同程度的抑制,其耐受性也尽不相同,经过分析和比较后得出5种藻类对铬的耐受性大小顺序为:微囊藻(Microcystis)＞水华鱼腥藻(Anabaena flos-aquae)＞细长聚球藻(Synechococcus elongatus)＞斜生栅藻(Scenedesmus obliquus)＞蛋白核小球藻(Chlorella pyrenoidose).     

我国几种典型树种非甲烷烃类的排放特征

采用封闭式采样法和带有预浓缩及程序升温装置的熔融毛细管柱气相色谱仪，对我国的松、柏、杨、槐等几种典型树种排放非甲烷烃类（ＮＭＨＣ）的组成和排放速率进行了定性和定量测定，初步确定了不同树种和的特征物种和排放规律，结果表明，针叶树种和阔叶树种排放的ＮＭＨＣ组成差别很大，各树种的排放规律除了与自身的结构和生理活动等在内在因素有关外，还在不同程度上受到外界因素（主要是温度和光强）的影响，一般温度越高，光强     

Physico-chemical characterization and source tracking of black carbon at a suburban site in Beijing

Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC (black carbon) samples. TEM (transmission electron microscopy) results indicate that BC from combustion sources shows various patterns, and airborne BC appears spherical and about 50 nm in diameter with a homogeneous surface and turbostratic structure. The BET (Barrett–Emmett–Teller) results suggest that the surface areas of these BC particles fall in the range of 3–23 m²/g, with a total pore volume of 0.03–0.05 cm³/g and a mean pore diameter of 7–53 nm. The nitrogen adsorption–desorption isotherms are indicative of the accumulation mode and uniform pore size. O₂-TPO (temperature programmed oxidation) profiles suggest that the airborne BC oxidation could be classified as the oxidation of amorphous carbon, which falls in the range of 406–490°C with peaks at 418, 423 and 475°C, respectively. Generally, the BC characteristics and source analysis suggest that airborne BC most likely comes from diesel vehicle emission at this site.     

北京地区大气中非甲烷碳氢化合物（NMHC）的人为源排放特征研究

以能源为线索,运用气相色谱－质谱－计算机联用手段,对北京地区大气中各人为源排放的NMHC进行了分类定量测定。在此基础上分析了石油化工、交通、燃煤和居民液化石油气NMHC的排放特征及对北京地区大气NMHC的贡献。结果表明,交通运输和石油化工是对大气中NMHC贡献最大的人为源,其次是燃煤工业。对大气中NMHC的特征物种也进行了尝试性的研究。     

Ozonation of azo dye Acid Red 14 in a microporous tube-in-tube microchannel reactor: decolorization and mechanism

Despite the great success of time-weighted average passive sampling of hydrophobic contaminants, such as PCBs and PAHs, the sampling of polar organic compounds still presents a challenge because the equilibrium between water and most sampling phases is attained in a relatively short time. In this study, we proposed a new time-integrative sampler using in situ solvent extraction (TISIS) for polar organic chemicals. The sampler was composed of a 15 cm poly(dimethylsiloxane) (PDMS) tubing, with an internal diameter of 0.5 mm and wall thickness of 0.5 mm, through which an extraction solvent (acetonitrile) was passed. Four polar organic contaminants, caffeine, atrazine, diuron and 17α-ethynylestradiol, were chosen for the evaluation of the performance of the sampler. Without the use of in situ solvent extraction, the PDMS tubing when exposed to a constant aqueous concentration of the four model compounds was able to linearly accumulate those compounds for less than 12 h and equilibrium between the PDMS tubing and water was attained in 2 d under our laboratory conditions. However, TISIS when exposed to a constant aqueous concentration was able to linearly accumulate all the model compounds without any exposure time limitation. The measured sampling rates at three different extraction flow rates (0.2, 0.5, 1.5 mL min⁻¹) were similar, regardless of the chemicals, indicating that the overall mass transfer from aqueous solution to the extraction solvent was most likely dominated by partitioning to the PDMS tubing and the internal diffusion within PDMS. In addition, a pulsed exposure experiment confirmed that TISIS operated in a time-integrative mode when the environmental concentration was highly fluctuated.     

城市路口差异对行道树叶片叶绿素含量的影响研究

为明确城市道路路口差异对行道树叶片叶绿素的影响,研究选取太原市平阳路和长风街2条城市主干道为采样点,采摘春、秋季大十字路口、小十字路口、丁字路口和非路口绿化植株叶片,测定叶片叶绿素a含量、叶绿素b含量及叶绿素总量。结果表明:(1)城市交通对行道树叶片叶绿素总量影响为冬青卫矛(EuonymusjaponicusThunb)国槐(Sophora japonica)毛白杨(Populusto mentosa)。冬青卫矛适宜作指示物种。(2)与清洁对照区相比,污染区国槐和毛白杨叶片的叶绿素a、叶绿素b的含量及两者比值总体呈增加态势,冬青卫矛叶片叶绿素a、叶绿素b含量则以减少为主。(3)冬青卫矛叶片的叶绿素a含量相对叶绿素b含量影响明显,表现出了较好的相关性,建议用叶绿素a含量作为污染指示指标。(4)路口差异对不同种类行道树叶片叶绿素影响未显现一致性,表明路口差异受街道走向、交通流量、扩散能力、植株株高等多因素影响。在道路不畅、车流量大的区域,应在吸尘抑毒和降低绿化高度、增加扩散能力间寻求一种最佳平衡。     

青藏高原湖泊水质变化及现状评价

为探讨青藏高原湖泊水质变化及现状,于2016年9—10月在青藏高原面上东北部G315沿线,中部S301、S302、S206沿线,南部G219、G318沿线及叶如藏布流域采集湖泊水样,通过实验最终得到33个湖泊水样数据,包括22个构造湖和11个冰湖;同时,分析了湖泊水化学指标浓度、水化学组成和湖水矿化度空间分布,并与20世纪90年代以前湖泊矿化度做对比,以揭示青藏高原近几十年湖泊水质变化及驱动因素,探讨青藏高原湖泊水质现状.结果显示:(1)青藏高原湖泊水化学指标浓度和水化学组成差异显著,构造湖水样水化学指标浓度远高于冰湖水样.按离子总量分类,22个构造湖有6个淡水湖、4个微咸水湖、1个咸水湖、11个盐湖;而11个冰湖均属于淡水湖;按湖水化学类型分类,22个构造湖有6个为Ca~(2+)(Mg~(2+))-SO_4~(2-)型湖泊,16个为Na~+(K~+)-Cl~-型湖泊,而11个冰湖均为Ca~(2+)(Mg~(2+))-SO_4~(2-)型湖泊.(2)青藏高原湖水矿化度时空差异显著,自高纬向低纬湖泊矿化度降低,与20世纪90年代前对比研究发现,青藏高原部分湖泊矿化度较90年代前降低,湖泊水体呈淡化趋势,可能与青藏高原地区气候变暖、降水量和冰川融水增加、蒸发减少有关.(3)由于受地理环境、气候条件及水化学特性的共同影响,青藏高原大部分构造湖pH值、TDS严重超标,其次有6个湖泊也受到F-的污染;冰湖水体受到Fe、Mn、Cr、Ni的污染较为严重,尤其重金属元素Cr、Ni超标极为严重,可能与人类活动有关.     

Migration,Transformation and Removal of Macrolide Antibiotics in The Environment: A Review

Environmental Science and Pollution Research - Macrolide antibiotics (MAs), as a typical emerging pollutant, are widely detected in environmental media. When entering the environment, MAs can...