用沉积物、稀有鮈鲫和生物模拟采样器评价水体中PAHs和OCPs的生物富集和有效性

以官厅湿地为研究对象,通过分析多环芳烃(PAHs)和有机氯农药(OCPs)在沉积物中的浓度及在30 d暴露笼养稀有鮈鲫和三油酸甘油脂-醋酸纤维素复合膜(TECAM)中的富集水平,来评价PAHs和OCPs在水体中不同介质中的富集规律,并探讨了用TECAM膜对水生生物进行生物有效性评价的可行性.结果表明,目标污染物的沉积物生物富集系数(BSAF)和沉积物TECAM膜富集系数(TSAF)在湿地各点之间均存在着较大差异,变异系数分别在10%～70%和20%～50%之间,且BSAF和TSAF与Kow均没有一致的变化规律.对于所研究的目标污染物尤其是PAHs,稀有鮈鲫的BSAF值比平衡分配模型的预测值(在1～4之间)小1个数量级左右,而TSAF值则比较接近水生生物的模型预测值.同时也发现湿地中OCPs的BSAF和TSAF相互之间存在较好的相关关系,5个实验点相关系数分别为0.80、 0.87、 0.83、 0.85和0.84(p<0.01),而PAHs的BSAF和TSAF相关关系不显著(p>0.1).由此可见,联合应用沉积物、稀有鮈鲫和TECAM膜能更可靠更准确地评价PAHs和OCPs这类有机污染物在水体中的污染状况,TECAM膜作为一种生物模拟采样器能很好地预测鱼对OCPs这类较难降解有机污染物的生物富集,是对水体中疏水性有机污染物进行生态风险评价的一个有力工具.     

低碳经济与“两型社会”的相关性及指标研究

能源和环境是本世纪紧密关联的两个最重要问题,因此发展低碳经济,建设“两型社会”是中国寻求自身进一步发展的必经之路。首先在分析低碳经济与“两型社会”理念内涵的基础上,揭示了两者的关系,它们虽然是两个独立的概念,但也存在紧密联系;其次在“两型社会”建设中融入低碳经济发展的“脱钩”指标,它和其他指标一起评价“两型社会”的建设成果,是判断“两型社会”是否成功的重要标志。本文选择的低碳经济发展的“脱钩”指标主要包括能源消耗与经济增长的“脱钩”指标以及二氧化碳排放与经济增长的“脱钩”指标。这些低碳发展评价指标不仅能够反映经济增长与资源环境变化的响应关系,还能进一步评价“两型社会”建设成果,具有深远的理论和实践意义。     

Cladistic biogeographic analysis suggests an early Caribbean diversification in Mexico

The Great American Biotic Interchange has been the predominant paradigm for explaining biotic diversification in the Nearctic/Neotropical overlap or Mexican Transition Zone, which is commonly explained by the collision of the North and South American continental plates, which began in the Oligocene and fused both landmasses. In the most far-reaching cladistic biogeographical analysis of the area to date, evidence has been found supporting the existence of a remnant Caribbean region extending from eastern Mexico to southeastern USA, a hypothesis that challenges current views of the Great American Biotic Interchange and the Mexican Transition Zone. We show herein that an older terrane, which has drifted to the present day positions of Yucatan and Cuba, may be biogeographically linked to an early ‘Gondwanan’ biota of the Paleocene (ca. 60 Ma). The evidence indicates an east–west biotic divide in Mexico, existing before the collision and formation of Central America. The south–north division of the country, previously recognized by several authors as associated with the Great American Biotic Interchange and the Mexican Transition Zone, is of a younger age. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

基于同步辐射光源的X射线荧光分析技术研究匐枝青藓对铅污染的生物响应

为了研究苔藓植物对铅元素的富集特征和对铅污染的生物响应特性,选用多年生、植株体较大、分布广泛且易于采集的匐枝青藓(Brachythecium procumbens)为试验材料,在试验区使用不同浓度(0-3.0 mmol·L-1的Pb2+污染液对人工栽植的匐枝青藓进行了动态胁迫试验(7-28d).使用同步辐射光源的x射线...     

不同设置方式下的防风网抑尘效果对比

为对比防风网不同设置方式对露天堆场起尘的影响,以某露天煤堆场为例,结合现场实测数据对数值计算方法进行了验证,并根据实际堆场设计了4种设网方案。通过计算各料堆表面摩阻风速的分布,统计出了各方案下的全年起尘率。结果表明：当防风网呈＂口＂型设置时,抑尘效果最好;沿全年主导风向上方向呈＂L＂型设置时,抑尘效果最差。比较＂П＂型...     

火电厂SO_2污染治理设施运行率的确定方法研究

从分析我国火电行业脱硫现状入手,指出如何确定火电企业脱硫设施的运行率已成为二氧化硫总量核查的重点,但尚有较大的难度。主要为二氧化硫核查提供一种简捷、合理的测算脱硫设施运行率的方法。     

Effects of various pretreatment methods on mixed microflora to enhance biohydrogen production from corn stover hydrolysate

Effects on mixed microflora to enhance biohydrogen production from corn stover hydrolysate was studied.     

In vitro fluorescence displacement investigation of thyroxine transport disruption by bisphenol A

Bisphenol A (BPA) is a chemical with high production volume and wide applications in many industries. Although BPA is known as an endocrine disruptor, its toxic mechanisms have not been fully characterized. Due to its structural similarity to thyroid hormones thyroxine (T4) and triiodothyronine (T3), one possible mechanism of BPA toxicity is disruption of hormone transport by competitive binding with the transport proteins. In this study, the binding interactions of BPA, T4, and T3 with three thyroid hormone transport proteins, human serum albumin (HSA), transthyretin (TTR), and thyroxine-binding globulin (TBG) were investigated by fluorescence measurement. Using two site-specific fluorescence probes dansylamide and dansyl-L-proline, the binding constants of BPA with HSA at drug site I and site II were determined as 2.90 104 and 3.14 104 L/mol, respectively. By monitoring the intrinsic fluorescence of tryptophan, a binding constant of 4.70 103 L/mol was obtained. Similarly, by employing 8-anilino-1-naphthalenesulfonic acid as fluorescence probe, the binding a nity of BPA with TTR and TBG was measured to be 3.10 105 and 5.90 105 L/mol, respectively. In general, BPA showed lower binding a nity with the proteins than T3 did, and even lower a nity than T4. Using these binding constants, the amount of BPA which would bind to the transport proteins in human plasma was estimated. These results suggest that the concentrations of BPA commonly found in human plasma are probably not high enough to interfere with T4 transport.     

基于3S技术的呼和浩特市土地利用／覆盖变化研究

本文以呼和浩特市为研究对象,利用遥感（RS技术）、地理信息系统（GIS技术）以及全球定位系统技术（GPS技术）——简称3S技术,对呼和浩特市2000、2004年遥感影像进行了综合技术处理,获得2期土地利用现状图,据此对呼和浩特市土地利用变化幅度及变化速度、土地利用变化程度、土地利用变化空间动态进行了分析,为区域土地资源科学管理及实现区域土地资源可持续利用提供科学依据。     

Preliminary study of groundwater denitrification using a composite membrane bioreactor

A composite membrane bioreactor (CMBR) integrating the immobilized cell technique and the membrane separation technology was developed for groundwater denitrification. The CMBR had two well mixed compartments with one filled with the nitrate-containing influent and the other with a dilute ethanol solution; the compartments were separated by the composite membrane consisting of a microporous membrane facing the influent and an immobilized cell membrane facing the ethanol solution. Nitrate and ethanol molecules diffused from the respective compartments into the immobilized cell membrane where nitrate was reduced to gaseous nitrogen by the denitrifying bacteria present there with ethanol as the carbon source. The microporous membrane was attached to one side of the immobilized cell membrane for retention of the disaggregated bacteria. Relative to the single dose of external ethanol, the two-dose supplementation produced better treatment results as evidenced by the lower concentrations of NO₃⁻-N and ethanol (as measured by total organic carbon) of the effluent. The batch treatment in CMBR removed most of the nitrate in the influent and attained a stable denitrification rate of 0.1 g·m⁻²·h⁻¹ for most of the 96-h cycles during the 30-cycle study. The effluent was essentially free of ethanol and nitrite nitrogen.