中国土壤污染防治管理体系思考

对中国土壤污染防治管理体系法律、法规、规范性文件及标准体系等进行了总结和分析,得出中国现行土壤污染防治管理体系存在执法依据空缺、系统性缺乏、可操作性差和协调性弱等问题.在此基础上,对中国土壤污染防治管理体系提出改善建议,如加快立法进度,土壤污染防治法需考虑与其他环境要素保护法律之间的衔接,明确各方责任,完善土壤标准体系等.尽快完善中国土壤污染防治管理体系,为中国土壤污染防治工作提供有力的法律保障.     

主观性在环境侵权案件证据和证明中的作用研究

法院在审理环境侵权案件时,往往依赖于专业鉴定、行政标准、专家意见等等客观依据来确定案件事实.但因为环境问题的复杂性,以及民事主体自身举证能力的限制,经常出现双方举证均不充分,法院无法基于现有事实和证据得出结论的情况.此时,法官应当发挥自身能动性,主动应用主观的、甚至是非科学性的因素和手段,包括容忍义务、经验法则、自由心证等等,这些因素无法被赋予客观的标准,它需要法官基于自身的理性以及经验,结合社会一般观念、习惯等因素进行判断.     

废旧锂电池中有价金属的回收技术研究

锂电池以其优异的性能得到了广泛的应用,其废弃量也在逐步增加.如果不对其进行有效的处理回收,不仅给环境保护带来巨大的压力,而且也会造成钴、锂、镍和锰等有价金属的极大浪费.综述了国内外对废旧锂电池回收技术的研究现状,比较了不同回收途径的优缺点,讨论了回收技术的发展方向,着重介绍了共沉淀法在废旧锂电池有价金属回收中的应用.此外,随着锂离子电池生产技术的发展,新的电极材料将会出现并取代过渡金属氧化物,同时也需要相应的电解液与之匹配,这将向废旧锂电池回收技术提出了新的要求.     

津北大气干湿沉降重金属元素通量与评价研究

大气干湿沉降是有害物质进入土壤的一种重要途径,是影响农田生态系统安全的重要因素.天津市北部的蓟州区大气干湿沉降重金属元素具有以下特征:(1)大气干湿沉降重金属元素年沉降通量从大到小依次为Zn>Pb>Cr>Cu>Ni>As>Cd>Hg,Zn、Pb是大气干湿沉降重金属元素中最主要的元素,山区年沉降通量小于平原区,表明山区空气环境质量相对于平原区好,与天津城区、北京平原区、全国相比,津北蓟州区大气干湿沉降重金属各元素年沉降通量均相对较低;(2)大气干湿沉降物输入浓度中,Cd、Pb、Zn、Hg显著高于蓟州区土壤含量平均值,尤其是Cd,表明大气干湿沉降可能是土壤中Cd的重要来源;(3)根据大气干湿沉降物环境地球化学评价结果,大气干湿沉降物环境地球化学单指标和综合指标评价结果均为一等,表明该地区大气环境质量很好.     

深圳冬季边界层大气中污染物垂直分布特征

为更好地掌握深圳城区近地边界层大气污染物的性质、来源及大气理化过程,2017年冬季利用深圳市356 m石岩梯度观测塔进行大气主要污染物的垂直观测,获得包括4个高度(60 m/70 m、110 m/120 m、210 m/220 m和325 m/335 m)的污染物浓度垂直分布廓线.分析了不同高度浓度的垂直廓线、相关性和日变化特征,并探讨了风向风速对其的影响.结果表明,SO_2浓度随高度升高先降低再升高,在高空存在明显的区域输送特征;NO_x、PM_(2.5)、PM_(10)浓度随高度升高而下降,70 m高度近地大气中NO_x和PM_(2.5)受局地源影响显著,白天存在由近地大气向上混合扩散的过程,而PM_(10)中的粗粒子部分在整个气层中显现出一个比较稳定的本底值;O_3浓度随高度升高而升高,主要由于夜间高空O_3缺乏NO的滴定反应而具有一个较高的背景值.     

Genomewide analysis indicates that queen larvae have lower methylation levels in the honey bee (Apis mellifera)

The honey bee is a social insect characterized by caste differentiation, by which a young larva can develop into either a queen or a worker. Despite possessing the same genome, queen and workers display marked differences in reproductive capacity, physiology, and behavior. Recent studies have shown that DNA methylation plays important roles in caste differentiation. To further explore the roles of DNA methylation in this process, we analyzed DNA methylome profiles of both queen larvae (QL) and worker larvae (WL) of different ages (2, 4, and 6 day old), by using methylated DNA immunoprecipitation-sequencing (meDIP-seq) technique. The global DNA methylation levels varied between the larvae of two castes. DNA methylation increased from 2-day- to 4-day-old QL and then decreased in 6-day-old larvae. In WL, methylation levels increased with age. The methylcytosines in both larvae were enriched in introns, followed by coding sequence (CDS) regions, CpG islands, 2 kbp downstream and upstream of genes, and 5′ and 3′ untranslated regions (UTRs). The number of differentially methylated genes (DMGs) in 2-, 4-, and 6-day-old QL and WL was 725, 3,013, and 5,049, respectively. Compared to 4- and 6-day-old WL, a large number of genes in QL were downmethylated, which were involved in many processes including development, reproduction, and metabolic regulation. In addition, some DMGs were concerned with caste differentiation.     

PAHs pass through the cell wall and partition into organelles of arbuscular mycorrhizal roots of ryegrass

The subcellular process and distribution of polycyclic aromatic hydrocarbons (PAHs) in arbuscular mycorrhizal plants remains to be elucidated. This work used a greenhouse experiment to show that, accompanied by the apoplastic and symplastic water movement through the root, acenaphthene (ACE) as a representative PAH passed through the cell-wall boundary, dissolved in the cell solution, and partition organelles in arbuscular mycorrhizal roots of ryegrass (Lolium multiflorum Lam.). The observed concentrations of ACE in organelles were 0.6 to 4.4 times higher than in the cell walls. The cell wall and organelles were the dominant storage domains for ACE in the root, and the distribution of ACE in cells of mycorrhizal ryegrass roots was, in descending order, cell organelles (40.8-70.8%) > cell wall (19.7-3.8%) cell solution (9.6-20.5%).     

行为形成因子分析方法评述

为全面了解人因可靠性分析(HRA)中行为形成因子(PSF),对现有的PSF分析方法进行评述。分析情景环境的各种称谓,指出PSF是目前认可程度最高的一种,并规范PSF的定义及其内涵。分2种类型评述当前PSF的分类方法:基于影响机理分类和系统化分类。评述在HRA中PSF的选择和使用情况,针对不同的问题给出选择和使用PSF的建议。分别从定性评价和定量评价2个方面对PSF的评价方法进行评述。结果表明,PSF分析方法仍处于发展之中,需要在后续工作中不断改进。     

Local consumers induce resistance differentially between Spartina populations in the field

Intraspecific variation in the strength of inducible plant defenses plays a central role in the interactions between plants and herbivores. Studies of this variation are typically conducted in the greenhouse or laboratory rather than the field. We simultaneously manipulated densities of local consumers in the field within Maine and South Carolina populations of the smooth cordgrass Spartina alterniflora. South Carolina, but not Maine, plants induced resistance when grazed by local consumers. South Carolina populations of Littoraria snails and planthoppers colonized control more than previously grazed South Carolina plants, and Littoraria snails consumed more control than previously grazed plants. The inducible feeding deterrents in South Carolina plants appear to be water soluble, but not phenolic based. In contrast, grazed and control plants from Maine populations did not differ in attractiveness or palatability to Maine consumers. Thus, inducible plant responses by South Carolina plants had a strong effect on the South Carolina consumer community, but no analogous effect occurred in Maine. Field experiments are a powerful approach to detecting the strength of inducible plant resistance and its impacts on local consumers, which in this case were shown to vary with location.