兰州及其周边区域大气降水δ18O特征及其水汽来源

根据2011年4月~2012年3月在兰州及其周边区域永登、皋兰和榆中这4个站点所采集到的243个大气降水样品及同期相关气象资料,对兰州及其周边区域大气降水中稳定同位素的时空变化特征及其环境效应进行了分析,通过回归分析建立了大气降水线方程,同时采用HYSPLIT 4.9模型对兰州及其周边区域水汽来源进行了追踪,并建立水汽输送模式.结果表明,兰州及其周边区域的大气降水线方程为δD=7.48δ18O+8.13,表明该区局地蒸发较强烈;在时间变化上,降水中同位素值表现为冬低夏高,而d-excess值变化趋势较为平稳,但不同时段下,也存在着一定的变化;从空间分布来看,由西至东加权平均δ18O值呈减小趋势;降水δ18O与温度呈正相关关系,而与降水量表现为负相关;在大尺度下,西风水汽、局地水汽以及东南季风水汽均对兰州及其周边区域有一定的影响,其中西风水汽占主导作用,而东南季风水汽的影响在时间上有一定的局限性,主要集中在6月初至8月初这一时段.     

海水养殖自身污染机制及其对环境的影响

对近年来海水养殖自身污染方面的研究作了全面的综述,探讨了投饵养殖和非投饵养殖两种类型,特别是在养殖、网箱养殖、池塘养殖模式自身污染产生的机制和对水体环境的影响,并提出了防止和减轻自身污染的对策。     

环境政策的综合影响评价模型系统及应用

研究和建立一套以可计算的均衡理论模型(CGE)为核心,同时与大气环境质量模型和健康影响模型(暴露-反应模型)连接,组成了环境政策综合评价模型,为综合评价环境政策产生的各类影响及其相互作用提供了一种评价方法.利用该模型系统,分析北京市采用能源环境税对北京市的大气环境、健康、经济发展和居民福利水平的影响.模型分析认为,北京市采用单一的能源环境税可以改善北京市的大气环境,但也将迟缓北京市的经济发展;如果北京市在采用能源环境税的同时进行绿色环境税收制度改革,则不但可以改善环境,而且可以促进北京市的可持续发展.     

中国PM2.5污染健康效应的国民经济影响分析

为合理评估PM_2.5污染,通过Meta分析,系统回顾已有文献并对中国人群的PM_2.5健康效应进行定量评估.在此基础上,综合运用Benmap模型和CGE模型,估计2017年全国PM_2.5污染造成的国民经济影响.结果表明,中国PM_2.5污染造成的全因早逝、慢性阻塞性肺病（住院）、脑卒中（住院）、缺血性心脏病（住院）、心血管疾病（门诊）、呼吸系统疾病（门诊）OR值分别为1.007（95% CI：1.005,1.009）、1.014（95% CI：1.009,1.019）、1.006（95% CI：1.002,1.011）、1.007（95% CI：1.005,1.010）、1.006（95% CI：1.002,1.010）、1.006（95% CI：1.004,1.008）（per 10μg/m³）.2017年,PM_2.5污染引起的中国年均劳动损失为2590.34万d,居民额外医疗支出为86.39亿元,造成的经济损失约占当年GDP的1.48%.     

土壤溶解有机碳的研究进展

系统地综述了DOC的来源、组成、性质、影响因素、环境效应及测定方法等。尽管关于土壤DOC的研究目前还不完善,至今对DOC的组成、性质等问题都不是很清楚,但现有的研究已经表明,DOC是土壤圈中一种非常活跃的化学物质,它对土壤中化学物质的溶解、吸附、解吸、迁移和毒性等行为均有显著的影响。     

Response of organic aerosol characteristics to emission reduction in Yangtze River Delta region

● The emission reduction causes significant change in organic aerosol composition. ● The atmospheric oxidizing capacity improved during emission reduction. ● The mixed oxygenated organic aerosol contributed higher during emission reduction. Organic aerosol (OA) is a major component of atmospheric particulate matter (PM) with complex composition and formation processes influenced by various factors. Emission reduction can alter both precursors and oxidants which further affects secondary OA formation. Here we provide an observational analysis of secondary OA (SOA) variation properties in Yangtze River Delta (YRD) of eastern China in response to large scale of emission reduction during Chinese New Year (CNY) holidays from 2015 to 2020, and the COVID-19 pandemic period from January to March, 2020. We found a 17% increase of SOA proportion during the COVID lockdown. The relative enrichment of SOA is also found during multi-year CNY holidays with dramatic reduction of anthropogenic emissions. Two types of oxygenated OA (OOA) influenced by mixed emissions and SOA formation were found to be the dominant components during the lockdown in YRD region. Our results highlight that these emission-reduction-induced changes in organic aerosol need to be considered in the future to optimize air pollution control measures.     

The Behaviour of Selenium in Geological Processes

Selenium contents were analyzed from a total of 244 soil samples collected over different rock types at a sampling density of one sample per 4km² around Geita gold mining areas, Northwestern Tanzania. Comparisons using literature survey contents of selenium in geological materials and some implications on the selenium in soils are compiled and discussed. Most selenium occurs as simple selenides in small quantities in low temperature hydrothermal deposits devoid of sulphur. It has been observed that to a large extent selenium content is increased more than most trace elements in the upper parts of the Earth perhaps through extraterrestrial deposition. In deep-seated rocks selenium is associated with sulphur but being volatile selenium and sulphur do not behave according to the crystallochemical law. Due to the higher stability of S⁶⁺, Se⁴⁺ and Se⁰ separate during migration. Thus, selenium is especially found in deep-seated plutonic rocks where large magma bodies cooled slowly and sulphur is available to precipitate sulphides. Selenium, which occurs with sulphides, is inhomogeneously deposited into continental margins. It is increased during magmatic differentiation and is highest in basic rocks. In magmatic and metamorphic conditions, selenium is found in the crystal structures of sulphides while in pneumatolytic and hydrothermal processes, it is relatively enriched into the late differentiates compared to sulphur. In metamorphic rocks selenium is more widely distributed. Selenium content in soils in the investigated area varies from (0.3–0.5gg^–1) in laterite and in black cotton soil 0.4gg^–1. Of all volcanic rocks selenium is highest in volcanogenic rocks especially the basalts. Surface waters are enriched in selenium, which they leach from volcanic materials. Selenium in sediments containing clay and organic matter is elevated but the content decreases with increased metamorphism. Selenium in volcanic areas can be used as a pathfinder in prospecting for volcanogenic ore deposits. S/Se ratios are distinct in different rock types and can thus be used to elucidate the origin of rocks, ores, and sediments.     

高Cu、高Zn对白星花金龟幼虫的毒性作用

Cu(铜)和Zn(锌)是环境中最常见的重金属污染元素,为探究其对白星花金龟幼虫的毒性,采用滤纸接触法、人工土壤法和菌渣培养法研究了高Cu、高Zn对白星花金龟幼虫的生长及氧化胁迫效应。结果表明,滤纸接触法和人工土壤法中试验浓度Cu、Zn对白星花金龟幼虫死亡率无明显影响。菌渣培养法中虫体的取食抑制率和体重增长抑制率均与Cu、Zn浓度呈显著性正相关关系;Cu处理诱导了虫体可溶性蛋白含量的增加,抑制了SOD(超氧化物歧化酶)、GST(谷胱甘肽转移酶)的活性和MDA(丙二醛)的产生,对CAT(过氧化物酶)活性没有显著影响;Zn浓度为3 500和5 000 mg·kg-1的处理组可溶性蛋白含量被显著诱导、MDA含量被显著抑制,浓度为2 000和6 500 mg·kg-1处理组的SOD活性被激活(P0.05),Zn胁迫未对CAT、GST活性造成明显影响。表明Cu、Zn污染对白星花金龟幼虫生长具有毒性效应,在评价高浓度的重金属污染对虫体的毒性作用时,不能仅采用SOD、CAT、GST等指标作为标志物,需要综合其他指标进行分析。     

三丁基锡对孔雀鱼的毒性效应研究

采用静态暴露方式研究三丁基锡氯化物(TBTCl)对孔雀鱼的毒性效应.当幼鱼暴露于1.25-7.90μg·l-1的TBTCl 后,出现明显的急性中毒症状,96h的半致死浓度(LC50)为5.82μg·l-1; 成鱼在0.14-3.56μg·l-1浓度下暴露10-30d,TBTCl能诱导雌鱼的肝体指数升高,并使肝脏和脾脏组织的显微结构发生明显的病理变化,毒害作用具有明显的剂量-效应和时间-效应关系.表明肝体指数以及肝脏、脾脏等组织的病理学变化可以作为评估三丁基锡等环境污染物的生物指标.     

廊道效应与城市景观结构

根据景观学原理，本文将城市廊道分为两类，人工廊道与自然廊道，并着重分析城市廊道的场效应，研究表明，廊道效应产生的实质在于廊道效益是距离的函数，因而可用指数衰减曲线表示，从理论上分析，人工廊道与自然廊道场效应的分界点即综合效益极大点，自然廊道在两条人工廊之间存在的合理依据是：至少存在两个分别与两条指数衰减曲线相交的综合效益极值点。根据廊道效应原 文对北京古代传统规划格局进行分析，发生在天人鸽 与择中