西溪湿地底泥中有机氯农药分布特征及风险评价

以西溪湿地为主要研究区域,采集了西溪湿地主要河口的表层和柱状底泥样品,以气相色谱(GC)/电子捕获检测器(ECD)定量测定样品中滴滴涕(DDTs)、六六六(HCHs)的含量,并对其进行生态风险评价.结果表明:(1)西溪湿地底泥样品中DDTs浓度明显比HCHs高.有机氯农药(OCPs)在研究区域内的底泥表层样品中残留呈现...     

Analyzing nutrient distribution in different particle-size municipal aged refuse

To investigate the feasibility of using aged municipal solid waste as farmland soil, it is essential to study its nutritive compositions for plant growth. Previous studies have demonstrated that the properties of different particle-size aged refuse are very different, therefore, the present study was conducted to evaluate the adequacy of three elements (N, P, K) and the fractionation of inorganic P in the aged refuse with a particle-size distribution of 900 to 300, 300 to 150, 150 to 105, 105 to 90 and 90 to 0 μm. The results indicate that (1) total quantities of N, P, K were much larger than that in the general soil and the quantities of available N, P and K were also adequate; (2) total content of P was sufficient, but the ratio of available-P to total P was not high enough; (3) with the decrease of particle size, the contents of these elements presented different trends. The results implicate that total contents of N, P and K were enough for the aged refuse being exploited as cultivated soil, and different gradation of aged refuse could be added to improve poor soils. It provides scientific evidence for utilizing different particle-size aged refuse comprehensively.     

Net anthropogenic nitrogen accumulation in the Beijing metropolitan region

Background, aim, and scope  

A rapid increase in anthropogenic nitrogen inputs has a strong impact on terrestrial and aquatic ecosystems. We have estimated net anthropogenic nitrogen accumulation (NANA) as an index of nitrogen (N) pollution potential in the Beijing metropolitan region, China. Our research provides a basis for understanding the potential impact of anthropogenic N inputs on environmental problems, such as nation-wide water quality degradation under the current rapid urban expansion in modern China.     

广玉兰提取物对铜绿微囊藻抑制作用的机制研究

采用前期研究发现的可显著抑制铜绿微囊藻的广玉兰正己烷和正丁醇提取物,对其抑藻机制进行初步研究.研究发现,经广玉兰提取物处理后,藻细胞的叶绿素a含量显著减少;超氧化物歧化酶(SOD)活性先升后降;细胞膜透性显著增强,最高值达到对照组的7～8倍.同时,藻细胞的超微结构也相应地发生改变,具体表现为:细胞变形,质膜皱缩甚至断裂...     

Oxidative stress, endothelial dysfunction and inflammatory response in rat heart to NO₂ inhalation exposure

Epidemiological studies suggest that NO₂ inhalation is associated with adverse effects on heart-related health, however, existing experimental data lack relevant evidences. In this study, a role for oxidative stress, endothelial dysfunction and inflammatory responses in the heart of rats treated with different concentrations of NO₂ (0, 5, 10 and 20 mg m⁻³) was investigated. Mild heart pathology occurred after 7-d exposure (6 h d⁻¹). Marked oxidative stress were induced as evaluated by reduction/induction of antioxidants (Cu/Zn-SOD, Mn-SOD and GPx) activity and increasing formation of MDA and PCO. Also, mRNA and protein biomarkers of vasoconstriction (ET-1, eNOS) and inflammation (TNF-α, IL-1β and ICAM-1) were up-regulated, and p53 mRNA expression, bax/bcl-2 ratio and the mean number of TUNEL-positive myocytes were increased as well. All the results implicate that NO₂ exerted injuries to mammals’ heart, and the damage mechanisms were possibly associated with oxidative stress, endothelial dysfunction and inflammation.     

Release of hexachlorocyclohexanes from historically and freshly contaminated soils in China: implications for fate and regulation

Hexachlorocyclohexanes (HCHs) were produced and used in large quantity worldwide and are common soil pollutants. In this study, desorption of α-HCH and γ-HCH from two soil samples collected from a historical pesticide plant in Tianjin, China, was examined. As a comparison, desorption of freshly sorbed γ-HCH was examined, using five typical Chinese soils. Strong resistant desorption was observed for both historically contaminated and freshly contaminated soils, and desorption results were well modeled with a biphasic desorption isotherm. The unique thermodynamic characteristics associated with the desorption-resistant fraction indicated that physical constraint within soil organic matrices was likely the predominant mechanism controlling resistant desorption. Resistant desorption could have significant effects on fate and exposure of HCHs in soil environment. More accurate biphasic desorption models that take into account of the resistant desorption can be used to facilitate regulating, management and remediation of HCH-contaminated sites.     

Assessing the phytotoxicity of different particle-size aged refuse using Zea mays L. bioassay

With increasing attention paid to the recycling use of aged refuse as vegetated soil, it is important to check its possible polluting risk and probe the tolerance of plant system to its stress. For this reason, several physiological responses in Zea mays L. (maize) to the leaching samples of aged refuse in different particle-size (900-300, 300-150, 150-105, 105-90, and 90-0 microm) were investigated in the present study, including growth, lipid peroxidation, protein oxidation and activities of antioxidant enzymes. The results indicate that the aged refuse affected the growth of maize seedlings, and elevated the levels of lipid peroxidation and protein oxidation in leaf tissues in a time-dependent manner, accompanying by the changes of antioxidant status. Also, above physiological responses varied as a function of particle-size distribution of the aged refuse, and statistical growth inhibition and oxidative stress occurred after the exposure of smaller particle-size samples, which contained higher level trace metals, the characteristic pollutants in the aged refuse. The results implicate that aged refuse might cause environmental stress on plant system, but the polluting risk mainly resulted from smaller particle-size samples. Therefore, the critical point of utilizing aged refuse as vegetated soil focused on analyzing its particle-size distribution, and screening out appropriate particle-size samples.     

垃圾渗滤液在黄土层中的渗透模拟试验

通过渗滤液与清水在压实黄土柱中长期连续渗透对比试验,分析了在相同入渗条件下渗滤液与清水两者入渗率随时间的变化规律及其影响作用.试验结果表明,渗滤液入渗曲线呈波动状态,先后变化不大,清水入渗曲线则呈先升高再降低后又缓慢升高的变化趋势,渗滤液平均入渗率只有清水入渗率的12%.影响两者入渗率差异的根本因素是渗液性质导致的影响作用的不同.渗滤液入渗率影响作用主要包括微生物作用、水-岩相互作用与吸附、过滤等作用.清水入渗率主要受水-岩相互作用的影响.     

宁夏春季沙尘暴暴发的环流及OLR场特征分析

利用宁夏1970—2003年沙尘暴时序资料,结合NCEP／NCAR月平均全球再分析和逸出长波幅时（OLR）月平均资料,对宁夏春季（3—5月）沙尘暴多发年和少发年高低层高度场和纬向风剖面场以及OLR场的差异特征进行了合成对比诊断分析。结果表明：不同时期的春季,宁夏沙尘暴多发或少发与位势高度场和急流区的位置及强度密切相关。沙尘暴多发年,500hPa蒙古西部到河西为较强的负距平区,200hPa急流区位于河套北部;沙尘暴少发年,高层负距平区及急流区位置明显偏北、偏东。不仅如此,中低纬度的青藏高原及西太平洋地区OLR的不同分布与宁夏沙尘暴多发或少发也有明显的对应关系,沙尘暴多发年,贝加尔湖到河套地区为负距平区,青藏高原以正距平为主,西太平洋地区也基本为正距平;而沙尘暴少发年,OLR则呈相反分布。     

水体低氧的早期暴露对青鳉(Oryzias latipes)后期的生长、性别比和繁殖能力的影响

水体低氧已是全球性生态问题,常以季节性、偶发性和昼夜间等不同形式存在于不同的水体中。长期低氧可影响鱼类正常的生长和繁殖,但鱼类早期生活阶段暴露于不同形式的低氧后,后期的生长和繁殖是否会受到不利影响,目前研究甚少。本研究在实验室模拟了连续低氧(2.8 mg·L~(-1)DO)(H1)、昼夜低氧(H2)和发生在胚胎器官形成时期的偶发性低氧(H3)等3种情景对青鳉胚胎的发育影响,评估了这一早期暴露对青鳉后期的生长、存活和繁殖的影响。我们发现,3种低氧方式都可以显著延长青鳉胚胎的孵化周期,引起胚胎卵黄囊吸收和鱼鳔发育异常;暴露结束120 d后,H1组青鳉成鱼的畸形率显著升高、存活率和生长速度都显著下降;H1、H2和H3组中成鱼的雌雄比都发生了改变,鱼群中以雄鱼为主,且产卵量和受精率都显著下降。结果表明,鱼类早期胚胎发育阶段所受到的低氧暴露可对后期生长和繁殖产生不利影响,对子代补充和种群稳定产生重要影响;鱼类关键发育期所经历的低氧事件,以及昼夜低氧事件所产生的生态后果不容忽视。