黄海近岸表层沉积物中PAHs的分布特征与潜在风险

利用第二次全国海洋污染基线调查数据,考察了我国黄海近岸海域表层沉积物中多环芳烃(PAHs)的分布状况、组成比例,并开展了初步的来源分析和潜在生态风险评价.研究结果表明,PAHs的含量范围从未检出至8294 ng·g-1,高值站点主要位于辽东半岛的大连湾附近海区,以及山东半岛北部的威海沿岸.在辽东半岛、山东半岛的近岸海区,表层沉积物中的PAHs以中、高环(4～5环)组分占据明显优势;而在江苏近岸海区,低环组分(2～3环)的比例明显上升.低环与中高环组分的相对丰度以及成对同分异构体的比值结果显示,各海区表层沉积物中PAHs的主要来源是各类燃烧释放过程,如燃煤、生物质、天然气和交通尾气等,石油产品输入的影响居次要地位.依据效应低值区间ERL的警戒水平,计算ERL商的平均值,从而初步得到各海区潜在的PAHs生态风险水平.结果表明,大连湾PAHs污染较为严重,各PAHs组分的浓度均高于ERL警戒水平,而苯并(a)芘甚至超出效应中值区间的境界水平ERM,显示大连湾近岸海区具有较高的PAHs生态风险,而其它海区的潜在生态风险则较低.     

A~2/O工艺在低温低浓度条件下处理效果及节能减耗研究

研究在低水温条件下,进厂污水中有机物浓度较低时(污水平均BOD5为45 mg/L左右),漳扎污水处理厂生化系统较优的运行工况。研究结果表明,在上述情况下,较优的连续运行工况为:污泥回流比为75%左右,MLSS为3 200~3 500 mg/L,生化池处的溶解氧在0.7~1.3 mg/L之间;较优的间歇运行工况为:以曝气3 h停曝3 h的方式运行,生化池处的溶解氧在3~5 mg/L之间,污泥回流比为75%左右,MLSS为3 200~3 500 mg/L。上述两种运行工况对污水中的污染物质都有较高的去除率,能成功避免污泥解絮的发生,使系统中的微生物平稳过冬;其中间歇曝气方式能达到节能减耗的目的,建议在旅游淡季时采用该方式运行。     

废旧锂离子电池资源化技术研究

通过介绍废旧锂离子电池的组成成分及近年来废旧锂离子电池资源化处理技术的研究进展,提出目前主要回收方法有溶解分离法和直接回收正极材料的新型方法等,并对现有研究中存在的二次污染、安全性问题进行了初步探讨。     

矿地复垦执行保证金的法治化问题研究

矿地复垦的市场调控失灵导致负外部性经济效果,政府命令与控制型因信息和寻租而同样失灵;保证金是弥补两个失灵时基于市场的政策工具,但要与矿地复垦协议共同使用。保证金的功能是担保矿地复垦合同的履行。复垦合同属行政管理中相对人自愿诺成行为,具有行政与民事的双重属性。行政机关的优益权和矿地验收决定等引起的争议属行政纠纷,救济要平衡合同主体双方,矿山利益和公共利益都要保护。这一切都要依靠理论研究、体制改革、培育中介机构等系列基础工程。     

土壤二维蒸气抽排去污效果的影响研究

土壤蒸气抽排是一种经济、高效、安全并已被广泛应用的污染场址现场修复技术,它能经济高效地去除非饱和带土壤中的挥发性有机污染物。以土壤和油污染物为例,进行了土壤二维抽排模拟实验,研究了气体抽排流量对去污效果的影响,通过实验可知:在增加气体抽排流量的情况下,抽排气中挥发性较强的有机物质正戊烷(C5h12)浓度下降的很快,最终保存在较低的浓度水平。挥发性一般的正辛烷(C8h18)和挥发性较弱的正癸烷(C10h22)经过长时间的抽排后,污染物也得到了降低,但是最终保持在比较高的浓度水平。得出增加气体抽排流量可以使污染物去除速率大幅度提高,从而缩短了净化时间,获得很好的去污效果。同时对二维抽排模拟实验和一维抽排模拟实验结果做了比较。     

地铁盾构施工风险评估与风险规避研究

深圳地铁二号线2202标段包括科苑站—红树湾站—世界之窗站,大部分采用盾构法施工。盾构隧道处于砂质粘性土地层填海地层,下穿4栋高尔夫别墅,存在基岩隆起、孤石和易出现施工扰动等情况。对2202标盾构施工进行安全评估,指出盾构机选型、盾构机进出洞及盾构施工过程中的风险源,如始发方向失控、盾尾卡死、洞口土体坍塌、地面建筑物出现不均匀沉降等,进而强调在施工过程中要正确辨识风险源,并根据地质、水文和周围环境条件研究采取适当的规避风险措施。     

基于安全社会学的高层建筑火灾事故剖析——以上海“11·15”特大火灾事故为例

结合我国基本国情及“11·15”特大火灾事故的具体情况,运用社会学视角,从技术和理性的局限、效益和安全的博弈、人因和制度的瓶颈三个方面透析由高层建筑火灾事故难以解决这一现状暴露出的社会学问题。并提出有利于从深层次上保障人民生命安全和公共财产安全的三点建议：调整引发不安全因素的社会结构;提升有利于确保安全的技术能力;加强政府的社会控制功能。本文针对我国高层建筑火灾事故频发的现状,揭示了“11·15”特大火灾事故带来的警示和反思,就高层建筑火灾防范提出了改进方法,对建筑、消防等部门的管理工作具有一定的参考意义。     

Assessment of elemental distribution and trace element contamination in surficial wetland sediments, Southern Tibetan Plateau

In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements(Ca and Mg), and nutrient(NO $_{3}^{-})$ were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007?C2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1?C22) and anthropogenic action (sites 23?C76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO $_{3}^{-}$ and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively.     

Enantioselective ecotoxicity of the herbicide dichlorprop and complexes formed with chitosan in two fresh water green algae

To reduce the leaching potential, to prevent groundwater contamination and to maintain the efficacy of a pesticide, natural polysaccharides have received increasing attention due to their biocompatibility and useful biological reactivity for controlled release formulations (CRFs) of pesticides. In this paper, the toxicities of the chiral herbicide dichlorprop (DCPP) and its complexes with chitosan molecules (DCPP-CS) and chitosan nanoparticles (DCPP-NP) to two different green algae were determined and compared. The inhibition rates of DCPP, DCPP-CS and DCPP-NP were determined at 24, 48, 72, 96, 120, 144, 168 h, and the results show that (S)-DCPP was more toxic to Chlorella vulgaris than (R)-DCPP, while the (R)-DCPP was more toxic to Scenedesmus obliquus than (S)-DCPP. The study also found that the chiral selectivity of DCPP to Chlorella vulgaris and Scenedesmus obliquus could be changed when DCPP was complexed with chitosan molecules (CS) or chitosan nanoparticles (NP). For Chlorella vulgaris, the order of inhibition was (R)-DCPP-CS > (S)-DCPP-CS and (R)-DCPP-NP > (S)-DCPP-NP; for Scenedesmus obliquus, the order was (S)-DCPP-CS > (R)-DCPP-CS and (S)-DCPP-NP > (R)-DCPP-NP. This phenomenon suggests that the enantioselective behaviors of chiral compounds might shift when interactions with other chiral receptors coexist in different biological environments. Additionally, chitosan molecules and chitosan nanoparticles also showed different toxicities, which could be ascribed to the difference in the physicochemical properties between CS and NP or the differences in the cell walls of the two fresh water green algae.     

探索基于中国国情的资源型城市高质量发展路径——写在专辑刊发之后的话

<正>资源型城市和地区是依托本地矿产、森林等自然资源开采加工和资源型产品生产输出为主要职能的城市和特殊类型区域。作为中国资源能源供应的主体和基础工业的主要集聚区,其在保障国家能源安全和社会主义现代化建设方面都贡献了重要力量。但因资源依赖性,资源型城市（地区）往往陷入“因资源而兴、受资源所困”的“资源诅咒”。放眼中外,资源型城市的转型发展一直是世界性难题,西方国家的经验表明,资源型城市转型是一个漫长的过程,无法一蹴而就。党的“二十大”报告提出,“高质量发展是全面建设社会主义现代化国家的首要任务”,要“加快构建新发展格局,着力推动高质量发展”。