喀斯特洞穴通风效应特征变化及其对洞内空气环境的影响研究——以贵州绥阳麻黄洞为例

为探究喀斯特洞穴内部空气变化特征,揭示喀斯特洞穴通风效应时空变化规律及其变化模式,于2016年1月～2019年6月间两个监测周期对贵州绥阳麻黄洞洞内外温度、湿度、C02浓度以及气压进行为期32个月的数据采集,并基于相关模型进行系统分析,结果表明:(1)麻黄洞存在3种通风模式:限制性通风模式、积极性通风模式和过渡阶段.其中夏季主要为限制性通风模式,洞内外气流交换较弱;冬季主要为积极性通风模式,洞内外气流交换运动明显,春季和秋季处于过渡阶段,两种模式交替存在.(2)洞道结构影响通风模式,同样,通风效应影响洞穴空气环境变化.根据洞道结构和通风效应对洞穴空气环境的影响可以将麻黄洞洞道分为3个部分:空气环境变化较大的1#～5#监测点、空气环境变化逐渐减小的6#～9#监测点以及空气环境稳定的10#～15#监测点.(3)受特殊的洞道结构影响,洞道中6#～9#存在"狭管效应"引起的"峡谷风",使得春秋两季洞道中部存在明显气流.基于模型分析洞穴通风效应及其对洞穴空气环境影响,研究喀斯特洞穴通风模式及其变化特征,对洞穴沉积物形成及气候变化及碳循环模式研究有重要意义.     

Characteristics and management modes of domestic waste in rural areas of developing countries: a case study of China

A huge accumulation of domestic waste has caused serious environmental contamination in rural areas of developing countries (RADIC). The characteristics and management of domestic waste are carefully discussed, based on field surveys and a literature review. The results indicate that the generation in most of RADIC is less than the median of 0.521 kg day⁻¹ per capita in China, and much smaller than in rural areas of developed countries (RADEC). Organic waste and inert waste with an accumulative mass percentage of 72.31% are dominant components of domestic waste in the rural areas of China. There are trends of increasing amounts of kitchen waste, paper/cardboard, and plastic/rubber and a decreasing trend of ash waste. The RADIC composition of domestic waste had a high content of organic waste and a low content of recyclable waste compared to the RADEC. Domestic waste has good compressibility and a light bulk density ranging from 40 to 650 kg m⁻³. The moisture, ash, combustible, and calorific values of domestic waste were 53.31%, 18.03%, 28.67%, and 5368 kJ kg⁻¹, respectively. The domestic waste has an abundance of nutrients including organic matter (39.05%), nitrogen (1.02%), phosphorus (0.50%), and potassium (1.42%). In RADIC, domestic waste can be used as an agricultural manure only after it has been collected and sorted for the potential risk of heavy metal accumulation. Based on these characteristics of domestic waste and the different situations of rural areas, four waste management modes including centralized treatment, decentralized treatment, group treatment, and mobile treatment are designed and discussed.

     

水文连通性对湖泊生态环境影响的研究进展

水文连通性对湖泊水资源调节、水质净化和生态安全等具有重要作用,但同时也可能带来潜在风险。因而厘清水文连通性对其生态环境的影响规律,对于开展水文连通性修复工作具有重要指导意义。基于广泛的文献调研,介绍了水文连通性的定义与内涵,分别综述了水文连通性对湖泊水文水动力、水质、水生态系统影响的研究进展。在此基础上,总结归纳了水文连通性通过改变水文水动力过程影响生态系统的路径：一是直接改变生境面积、植被格局和生物迁移繁殖特征,二是通过改变水质和沉积物特征而作用于生物的生长发育及其体内污染物累积转化过程。最后,对水文连通性变化的生态环境效应研究进行了展望：(1)加强对垂向连通性的研究以及拓展不同维度连通性耦合转化研究;(2）借助水动力-水质-水生态耦合模型研究水文连通性变化下的生态环境效应;(3）开展水文连通性的生态环境风险研究,并基于生态环境效益和社会经济效益权衡确定适宜的水文连通性。     

广花盆地地下水化学特征及其演化分析

粤港澳大湾区(简称大湾区)建设已经上升为中国国家重大发展战略,水资源保障能力提升是大湾区建设的重点内容。城市应急备用水源建设是解决区内供水风险、保障特殊时期供水安全的重要手段,查明水环境质量状况及其演化对于备用水源地的科学建设意义重大。以粤港澳大湾区应急备用水源地-广花盆地为研究对象,采集并测试了41口监测井水样的常规化学组分,利用主成分分析、元素比值和Gibbs模型等多种方法,探讨了地下水主要离子来源及控制因子,评估了水质状况。结果表明:地下水的TDS变化范围为51.42-1 293.36 mg·L-1,Cl-为1.81-858.65 mg·L-1,淡水样占比95.1%,微咸水占比4.9%,反映地下水化学具有较大的空间差异;地下水阳离子以Ca2+和Na+为主,阴离子以HCO3-和Cl-为主,为HCO3-Ca、HCO3-Na·Ca、HCO3·SO4-Na·Ca和HCO3·Cl-Na·Ca型水;地下水的ρ(Na+)/ρ(Na++Ca2+)值为0.02-0.59,ρ(Cl-)/(Cl-+HCO3-)值为0.03-0.88,Ca/Na值为0.69-52.66,HCO3/Na值为1.28-41.64,据Gibbs模型和元素化学计量分析表明,其化学组成主要受含水层碳酸盐岩和硅酸盐岩风化控制;Na/Cl系数为0.31-6.39,局部地下水盐化明显,在北部高Cl-质量浓度区,其主要受古咸水与现代淡水混合影响,并有Na+与Ca2+离子交换,在南部的高Cl-质量浓度区,可能是海水沿流溪河咸潮上溯和河流侧向补给地下水所致;氨氮为0.05-7.50mg·L-1,有75.6%的样品超过Ⅲ类水标准,其主要来源为农业施肥、人畜粪便。由此,氨氮污染威胁地下水安全,作为应急备用水源应引起高度重视。     

Different response of bacterial community to the changes of nutrients and pollutants in sediments from an urban river network

• Bacterial community varied spatially in sediments from the urban river network. • Key environmental factors shaping bacterial community were detected by RDA. • Bacterial co-occurrence networks changed at different levels of nutrient and metal. • Potential indicator species were selected to predict pollution risk in sediment. Microbial communities in sediment are an important indicator linking to environmental pollution in urban river systems. However, how the diversity and structure of bacterial communities in sediments from an urban river network respond to different environmental factors has not been well studied. The goal of this study was to understand the patterns of bacterial communities in sediments from a highly dense urbanized river network in the lower Yangtze River Delta by Illumina MiSeq sequencing. The correlations between bacterial communities, the environmental gradient and geographical distance were analyzed by redundancy analysis (RDA) and network methods. The diversity and richness of bacterial community in sediments increased from upstream to downstream consistently with the accumulation of nutrient in the urban river network. Bacterial community composition and structure showed obvious spatial changes, leading to two distinct groups, which were significantly related to the characteristics of nutrient and heavy metal in sediments. Humic substance, available nitrogen, available phosphorus, Zn, Cu, Hg and As were selected as the key environmental factors shaping the bacterial community in sediments based on RDA. The co-occurrence patterns of bacterial networks showed that positive interaction between bacterial communities increased but the connectivity among bacterial genera and stability of sediment ecosystem reduced under a higher content of nutrient and heavy metal in average. The sensitive and ubiquitous taxa with an overproportional response to key environmental factors were detected as indicator species, which provided a novel method for the prediction of the pollution risk of sediment in an urban river network.     

液相色谱串联高分辨质谱在水环境监测领域中的应用研究

简述了液相色谱串联高分辨质谱(LC-HRMS)的优势和其在水环境监测领域中的实际工作流程。分析了LCHRMS在水环境监测应用中面临的数据库储备相对匮乏和优先锁定定性目标相对滞后的问题,提出,通过建立目标化合物数据库,从厂家或供应商处购买与仪器匹配的数据库,建立高通量靶向监测和高通量非靶向筛查的体制机制,以及建立具有地方特色的特征污染物数据库等几种方式,以期进一步提高鉴别工作效率,更好地满足水环境监测的筛查需求。     

乳化液膜法处理化工废水的进展

扼要介绍了液膜分离的机理及其在废水处理方面所具有的特点，并举例说明了我国在液膜法处理化工废水方面的研究进展。     

Remembering the Past,Anticipating the Future: Community Learning and Adaptation Discourse in Media Commemorations of Catastrophic Wildfires in Colorado

Wildfire may be the clearest example to date of a socio-natural hazard that is being exacerbated by climate change, making wildfire an essential lens through which to investigate learning and adaptation in the Anthropocene. Here, we study discourse about simultaneous and recurring catastrophic wildfires in Colorado newspapers. We find that the wildfires’ anniversaries served as opportunities for critical reflection on hazard causality and mitigation in local media, particularly the first anniversary and especially for a community that experienced two catastrophic wildfires in a row. Two mediated prospective memory practices—invoking hindsight as foresight and recognizing a new normal—contributed to this discourse. However, learning and adaptation discourse faded in local media at later anniversaries. These findings contribute to learning and adaptation scholarship by connecting the concept of mediated prospective memory to disaster-related media studies and attending to the intricacies of anniversary commemoration under circumstances of simultaneous and recurring disasters.