近20年来鄱阳湖流域泛滥平原沉积物微量元素含量与污染变化

查明鄱阳湖流域微量元素的污染状况、识别其潜在来源并评估生态风险,对制定保护流域生态系统的有效策略至关重要.为了全面了解鄱阳湖流域5条主要支流泛滥平原沉积物中Cd、Hg、Pb、As、Cu、Zn、Cr、Ni、Mn、Sb、W和Sn等12种微量元素间隔近20 a的含量、污染水平和生态风险的时空变化状况,采用富集因子（EF）和修正综合污染指数（MPI）评价了微量元素的污染水平,应用潜在生态风险因子（E_r）和修正生态风险指数（MRI）量化了微量元素引发的生态风险,并对污染水平显著变化区域的污染源进行了分析和探讨.研究结果显示,近20年来,鄱阳湖流域泛滥平原沉积物中Cd、Zn、Mn、W和Pb含量分别升高了134%、26%、41%、25%和8%,Hg、As、Cr、Ni、Sb和Sn含量分别降低了35%、15%、22%、10%、14%和13%,Cu含量无明显变化;饶河、赣江和信江流域的Cd含量分别升高了331%、151%和107%,抚河、赣江和修水流域的Hg含量分别降低了87%、41%和40%;其污染变化主要表现为Cd污染加剧和Hg污染降级,整个赣江流域Cd污染升级至中度和中度-重度,饶河乐安江Cd污染升级至重度,抚河流域Hg污染降至无或轻微;Cd污染加剧导致综合污染升级,极度和重度污染点位比例由17%升至33%;极高生态风险点位的比例由11%升至22%,其高MRI贡献率元素由Hg变为Cd,源于Hg污染的极高生态风险点降至中等生态风险.鄱阳湖流域泛滥平原沉积物中微量元素的显著污染变化主要源于矿产开发与冶炼、工业和农业生产等人为活动.研究成果可为河流污染防治和流域生态系统的优化管理提供科学依据.     

基于Meta分析的矿业城市生态服务价值转移研究

采矿活动剧烈干扰了区域土地利用,对生态系统健康造成了严重影响。论文在综合国内若干资源型城市生态系统服务价值研究实例的基础上,提炼系列指标参数,运用Meta分析方法建立并验证了专门针对矿业城市耕地、林地、草地、水域的价值转移模型,并以河北省武安市为例估算了1987、2001和2014年的生态系统服务价值。研究结果表明：1）价值转移模型可以有效地评估矿业城市生态系统服务价值;2）武安市生态系统服务总价值呈现先增后减的趋势,2001年之后呈现快速下降状态;3）从地类面积来看,1987—2014年间武安市经济发展对生态用地产生的干扰程度为：耕地>草地>水域>林地,从服务价值角度看,干扰程度为：耕地>水域>草地>林地;4）在生态用地总面积减少的情况下,适当优化生态用地土地利用结构可以提高生态系统服务总价值。     

辽宁省西部和沈阳地区河水及地下水中溴的分布与污染特征

利用HPLC-ICP-MS方法分析辽宁省西部河水及其沿岸地下水中溴化物、溴酸盐的含量,调查了溴化物、溴酸盐的污染现状.结果表明,大凌河和小凌河河水中总溴浓度范围20.5-364μg·l~(-1),和总氯浓度呈良好相关关系,由回归方程得到的Br/Cl比值分别为2.91和0.83μg·mg~(-1).大凌河该比值在雨水的范围之内,而小凌河该比值则町能受到岩盐溶解的部分影响.大凌河和小凌河河水中溴与氯浓度的相关性与自然界观察到的天然比值范围足相符合的,表明河水未受到溴的污染.细河河水和地下水总溴浓度范围26.6-4070μg·l~(-1),平均浓度1584μg·l~(-1),Br/Cl比值范围2.73-25.2 μg·mg~(-1).细河河水和地下水中的溴浓度明显高于浑河、蒲河和沈抚灌渠,平均Br/Cl比值高达12μg·mg~(-1),远非降水来源所能解释.细河浅层地下水中溴酸盐被检出的浓度存在两处超标情况,分别为31和15μg·l~(-1).浅层地下水中高溴离子浓度和具有强烈毒理效应的溴酸盐的存在对该地区生态系统和人类健康具有潜在负面影响.     

乐安江河水和沉积物中Cu，Pb，Zn的时空变化特征及来源分析

德兴铜矿是亚洲最大的露天铜矿,其酸性矿山废水(AMD)对乐安江的影响在20世纪80—90年代曾得到了系统的评价. 然而,相比10年前,该矿山的产量已经增加4倍,但乐安江重金属污染变化情况目前尚不了解. 研究表明:乐安江河水、悬浮颗粒物和沉积物中重金属的空间分布主要与德兴铜矿和银山铅锌矿的AMD输入有关. 与10年前相比,如今由于乐安江上下游的几个重金属污染源被清理掉了,所采集到的样品中Cu,Pb和Zn的含量都比较低;而且由于贫铜矿石(w(Cu)<0.3%)得到了充分利用,乐安江沉积物中Cu含量明显下降.      

COVID-19疫情期间雄安地区VOCs的变化特征、臭氧生成潜势及来源解析

利用挥发性有机物(VOCs)在线监测数据对新冠肺炎疫情(COVID-19)期间(2019年12月25日～2020年2月24日)雄安地区环境空气中VOCs进行监测,探讨了疫情防控前、后VOCs的变化特征、臭氧生成潜势及来源解析.结果表明,疫情防控后φ(TVOCs)平均值为45.1×10-9,约为疫情防控前φ(TVOCs)...     

集安市世界遗产旅游发展现状及对策分析

高句丽王城、王陵和贵族墓葬世界文化遗产是已消失的高句丽文明的历史见证。该遗产地包括3座王城、14座王陵和26座贵族墓葬,其中除五女山城外,其他遗产均位于中国吉林省集安市境内。通过对集安遗产旅游发展的自身优势、机遇、问题进行综合分析,认为集安遗产旅游发展处于初级阶段,潜力巨大,并提出发展策略：确立旅游发展目标、加强城市营销,完善基础设施、提升交通网络通达性,拓宽融资渠道、构建文化遗产产业链及加强区域合作、协同发展。     

转型期西安市产业结构演进分析

选取了12个产业指标,运用区位熵和灰色关联分析相结合的方法测度了西安市各产业的区位优势及产业结构的关联度,分析了转型期西安市产业结构的演进.结果显示,西安市的三次产业结构组合仍需升级优化;在各行业演进中,科技、金融和房地产具有显著的区位优势.此外,通过对各产业发展的相似性测度得出2003年之前就业人员在第一、二产业之间的2-3个产业部门游移,之后从业人员开始在第三产业的一般性服务业(5-7个部门)游移,这显示出第三产业未来巨大的发展潜力与活力.     

Modelling the response of surface water quality to the urbanization in Xi'an, China

The study investigated the response of surface water quality to urbanization in Xi'an, China. We qualitatively described the change in urban land use from 1996 to 2003, analyzed the status of the surface water environment, and constructed a model of urban expansion to simulate the water environment's response to urbanization. Our results revealed that patterns of land use changed dramatically, the rate of economic growth exceeded that of urbanization during the study period, and increasing urban land use was correlated with fluctuations in water quality. The simulated results suggested that urbanization had reached the environmental carrying capacity based on the average land utility and the marginal costs of pollution.     

Assessment for Salinized Wasteland Expansion and Land Use Change Using GIS and Remote Sensing in the West Part of Northeast China

Due to human impact under climatic variations, western part of Northeast China has suffered substantial land degradation during past decades. This paper presents an integrated study of expansion process of salinized wasteland in Da’an County, a typical salt-affected area in Northeast China, by using Geographic Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of salinized wasteland expansion from 1954 to 2004, and land use/cover changes during this period. During the past 50 years, the salinized wasteland in study area have increased by 135,995 ha, and in 2004 covers 32.31% of the total area, in the meantime grassland has decreased by 104,697 ha and in 2004 covers only 13.15% of the study area. Grasslands, croplands and swamplands were found the three main land use types converted into salinized wasteland. Land use/cover changes shows that between 1954 and 2004, 48.6% of grasslands, 42.5% of swamplands, and 14.1% of croplands were transformed into salinized wasteland, respectively. Lastly, the major factors influencing salinized wasteland expansion and land use/cover changes were also explored. In general, climatic factors supplied a potential environment for soil salinization. Human-related factors, such as policy, population, overgrazing, and intensified and unreasonable utilization of land and water resources are the main causes of salinized wasteland expansion.     

Alcohol-related deaths among young passengers: An analysis of national alcohol-related fatal crashes

Introduction: There is consensus that riding with an impaired driver (RWI) constitutes a major threat to public health. The aim of this study was to characterize the factors contributing to the motor-vehicle deaths of 15–20 year-old (y/o) passengers that RWI with a peer. Method: Secondary analyses of the 2010–2018 Fatality Analysis Reporting System. 5,673 passengers aged 15–20 y/o killed while riding in passenger cars with a driver aged 21 or older, 3,542 of these drivers also aged 15–20 y/o. Analyses were conducted between October 2019 and December 2020. Results: Sixty-three percent of the young passengers were killed while riding with a driver 15–20 y/o. Of these drivers, 26.8% had a blood alcohol concentration (BAC) >0.00 g/dL and 77.1% had a BAC ≥0.08 g/dL. Compared with those occurring during the day on weekdays, fatalities of young passengers who RWI with a peer driver with a BAC ≥ 0.08 g/dL often occurred on weekend nights (OR = 8.2) and weekday nights (OR = 5.2), and when the passenger and driver were both male (OR = 1.8). Race/ethnicity was not a significant contributor to RWI fatalities. Conclusions: Most 15–20 y/o RWI fatalities occurred on weekends, at night, when the driver was a young peer with a high BAC, and the passenger and driver were male. The high prevalence of fatalities in these high-risk situations suggests that young driver-passenger dynamics may contribute to alcohol-related fatalities. Practical Applications: To curb RWI fatalities among underage passengers, countermeasures should focus not only on underage drinking drivers and riders, but also on drinking drivers of all ages. Prevention should increase focus on situations in which both the young passenger and young driver are males.