鱼体中多氯联苯的气相色谱/质谱分析研究

建立了鱼体中共平面多氯联苯(co-PCBs)和指示性多氯联苯(indicator PCBs)残留量的快速溶剂萃取气相色谱质谱分析方法.结果表明,18种多氯联苯在20 μg/L～500 μg/L范围内线性良好(r＞0.998),方法的检出限为0.2 ng/kg～0.5 ng/kg.当添加浓度为100 ng/kg时,多氯联苯的回收率为70.2％～113.5％.该方法前处理简便快速,准确性高,满足鱼体痕量多氯联苯残留的分析要求.     

基于底栖动物的松花江流域不同地形分区水质指标阈值研究

为全面了解松花江流域不同地形分区内底栖动物群落对水质指标的响应规律,识别不同分区水质指标指示物种的差异,于2016—2018年对松花江流域97个采样点的水质指标〔EC、ρ（DO）、ρ（COD_Mn）、ρ（NH₃-N）、ρ（TN）、ρ（TP）〕和大型底栖动物群落进行调查分析,采用临界指示物种分析法（threshold indicator taxa analysis,TITAN）分别探讨松花江流域山区、丘陵区和平原区水质指标的生态阈值,当污染物浓度超过负响应阈值时敏感种密度降低,当超过正响应阈值时耐受种也会受到明显影响,底栖动物群落结构会发生显著变化.将TITAN法所得的负响应阈值作为触发底栖动物群落发生变化的最低值,正响应阈值为底栖动物群落的耐受极限值.结果表明:①松花江流域水质指标在不同地形分区内的阈值不同,除ρ（DO）和ρ（COD_Mn）外,其他指标负响应阈值均表现为山区 < 丘陵区 < 平原区,ρ（DO）则表现相反,ρ（COD_Mn）在丘陵区出现最高阈值（5.46 mg/L）、山区出现最低阈值（4.01 mg/L）.除ρ（DO）以外,其他指标的正响应阈值均呈山区 < 丘陵区 < 平原区的趋势,ρ（DO）正响应阈值的变化趋势则与之相反.②松花江流域内超过50%的采样点水质指标值均超过其负响应阈值,超出正响应阈值的采样点比例在6%~40%之间,说明流域受到一定的干扰,但干扰程度不严重.③同一物种在不同地形分区内对水体理化指标的指示方向可能相反.萝卜螺属在丘陵区为ρ（NH₃-N）的正响应指示物种,在平原区则转变为负响应指示物种;短沟蜷属在丘陵区为ρ（TN）和ρ（TP）的正响应物种,在平原区则转变为负响应物种.研究显示,大型底栖动物群落结构的分布特征是影响水质指标阈值指示物种识别的主要原因,而不同分区的自然地理状况、栖境状况和水质状况则是造成大型底栖动物群落结构分布差异的主要因素.      

宁波三江口水域原核生物群落结构分析

首次应用16S rRNA基因-Illumina Miseq高通量测序技术对甬江流域宁波三江口区域的表层水体原核生物群落进行了分析,共获得215 504条高质量序列.多样性指数分析表明,该流域的水体原核生物群落具有较高的遗传多样性和丰富度.菌群分类分析发现,β-变形菌纲(β-Proteobacterium)、放线菌门(Actinobacteria)和拟杆菌门(Bacteroidetes)是主要的优势菌群,其相对丰度占总群落的78.88%.对比不同站位的原核生物群落,发现水文环境可能是影响三江口水域原核生物群落组成和结构的重要因素之一.与以往报道对比分析表明,甬江流域分布有多种污水和粪便污染指示菌,其中余姚江污染指示菌的丰度最高,说明其受污染的风险可能较高.病原菌BLASTN分析表明,在种和亚种水平上,分别检出76和18种潜在病原菌,占序列总量的2.19%和0.40%.本研究为系统认识甬江流域原核生物群落结构及生态功能提供了重要基础数据.     

基于三角模糊理论的尾矿库风险评价研究

根据尾矿库的特点和我国现行的尾矿库安全生产监督管理法律法规及标准规范的要求,构建了尾矿库风险评价指标体系。综合考虑评价指标对风险发生可能性及后果严重程度的不同影响来确定指标权重,同时考虑到权重确定和指标赋值中的模糊性和不确定性等问题,选用三角模糊理论建立了尾矿库风险评价模型,并以本溪某尾矿库为例进行说明。理论分析和实例计算表明,该方法对尾矿库风险评价有很好的适用性。     

Tessaria absinthioides: a possible bio‐monitor for Cd,Pb, and Cu,in the middle and lower basin of the loa river,North Chile

Some ecotoxic metals such as Cd, Pb, and Cu in Tessaria absinthioides were quantified to study its possible use as a bio‐indicator and/or bio‐monitor of these metals. This plant was chosen for its abundance in the area under study, along Chile and even in southern Latin America. For Cd, Pb, and Cu in all three parts of the plant (leaves, stems and roots) a different concentration pattern in each sampling areas was observed. In sampling areas Coya Sur and La Cascada copper and cadmium concentration decrease in order: leaves > roots > stems. In samples collected in Xalquincha the lowest concentrations of Cd and Pb were observed in stems. A maximum of cadmium concentration (9ug/gd.w. in leaves) was found in samples from La Cascada, a inflow to river Loa in Calama. High concentrations of lead were found in roots and leaves. Collected data demonstrate that the main pathway for cadmium is from ground water via roots into the plant. Some data obtained for lead and copper indicate that the influence of dust particles adsorbed on leaves and stems can be higher than uptake from ground water.     

Population Trends in Pacific Oceanic Sharks and the Utility of Regulations on Shark Finning

Accurate assessment of shark population status is essential for conservation but is often constrained by limited and unreliable data. To provide a basis for improved management of shark resources, we analyzed a long‐term record of species‐specific catches, sizes, and sexes of sharks collected by onboard observers in the western and central Pacific Ocean from 1995 to 2010. Using generalized linear models, we estimated population‐status indicators on the basis of catch rate and biological indicators of fishing pressure on the basis of median size to identify trends for blue (Prionace glauca), mako (Isurus spp.), oceanic whitetip (Carcharhinus longimanus), and silky (Carcharhinus falciformis) sharks. Standardized catch rates of longline fleets declined significantly for blue sharks in the North Pacific (by 5% per year [CI 2% to 8%]), for mako sharks in the North Pacific (by 7% per year [CI 3% to 11%]), and for oceanic whitetip sharks in tropical waters (by 17% per year [CI 14% to 20%]). Median lengths of silky and oceanic whitetip sharks decreased significantly in their core habitat, and almost all sampled silky sharks were immature. Our results are consistent with results of analyses of similar data sets. Combined, these results and evidence of targeted fishing for sharks in some regional fisheries heighten concerns for sustainable utilization, particularly for oceanic whitetip and North Pacific blue sharks. Regional regulations that prohibit shark finning (removal of fins and discarding of the carcass) were enacted in 2007 and are in many cases the only form of control on shark catches. However, there is little evidence of a reduction of finning in longline fisheries. In addition, silky and oceanic whitetip sharks are more frequently retained than finned, which suggests that even full implementation of and adherence to a finning prohibition may not substantially reduce mortality rates for these species. We argue that finning prohibitions divert attention from assessing whether catch levels are sustainable and that the need for management of sharks should not be addressed by measures that are simple to implement but complex to enforce and evaluate. Tendencias Poblacionales de Tiburones del Océano Pacífico y la Utilidad de Regulaciones sobre Cercenamiento de Aletas     

基于云模型的富水岩溶隧道涌水风险评价

为适应风险因素不确定性、随机性及动态反馈性等特点,建立新型富水岩溶隧道涌水风险评价体系,提出1种基于云模型的模糊综合评价方法.选取5个1级指标、29个2级指标构建评价指标体系;综合层次分析、熵权与加权平均计算法合理分配各指标权重;利用云生成算法计算出云数字特征参数并生成足够数量的云滴;将方法应用于贵州省某隧道涌水风险评...     

Developing Mechanism of Rubber-tea-chicken Agro-forestry Model in Tropical Area of China

As a typical tropical agro-forestry ecosystem in Wenchang,Hainan Province,China,rational mechanisms of the rubber-tea-chicken eco-agricultural model were studied with the Solow technological level index,stability indicator,harmonizing coefficient,grey correlation coefficient and production dominance.This study focused on rational hierarchical structure,the limiting factors and optimal strategies of the model development based on model structure,resource conditions and external market demands.Results showed that rational mechanism of the rubber-tea-chicken ecosystem model mainly included technological contributions,leverage function of dominance component(livestock husbandry),stability of the model structure and harmony of its components,the model dominant product’s market demand and government’s supporting policies.The contributions of fund,technology,information and talent resources played an important role in improving sustainability and productivity of the agro-forestry model.     

基于AHP和DEA模型的农业生态效率评价——以无锡市为例

农业面源污染已成为我国重要环境污染源之一,但由于农业面源污染具有分散、面广、周期长、随机性等特点,在评价上存在较大难度。根据生态效率理论,结合农业生产的特点,建立了综合考虑经济效益和环境影响的农业生态效率评价指标体系,并以江苏省无锡市为例,选取该市1998~2008年农业生产和面源污染相关数据,运用偏好锥的数据包络分析模型（DEA）对其农业生态效率进行了评价分析。结果显示：1998~2008年,无锡市农业生态效率呈现先下降后上升的趋势,近三年累计上升幅度达22%。表明近年来无锡市农业面源污染治理成效显著,农业可持续发展水平显著提高。提出的农业生态效率评价体系和方法为进一步推进农业面源污染治理工作提供了依据     

Postfire succession in a forest of the cryolithozone: The example of central Yakutia

The results of studies on postfire succession in larch forests of the permafrost zone are discussed. The main directions of successional processes in burned-out areas of different ages are described. It has been shown that secondary pyrogenic successions in larch forests follow the scheme of rapid regeneration without tree species replacement and the model of succession tolerance. Groups of plant species with different life strategies and indicator species characterizing different stages of the overgrowing of burned-out areas have been identified.