长江水体常量和微量元素的来源、分布与向海输送

基于2017年4～5月期间对长江干流与主要支流共20个站位的观测,结合多元数理统计对水体中溶解态常量和微量元素的空间分布规律、来源及入海通量进行了分析,并通过与世界其它河流的对比探讨了流域自然因素与人类活动等对长江水环境中常量与微量元素分布与输送的影响.结果表明,Cu、Zn、Pb、Cd和As是长江流域主要受人类活动影响的元素,在下游区域显著高于上游与中游(P 0. 05),且各元素在长江重庆段和汉江均有较流域其他河段高的浓度值,这些河段相对较高的重金属含量主要与人类活动强度密切相关.有趣的是,长江宜昌至武汉段各元素均出现了较低的浓度值,这很大程度上受三峡水利工程蓄水所产生的"滞留效应"所致.统计分析还显示Na、Mg、K、Ca、Fe、Mn、Co、Ni、Mo、Cr和V主要与各种岩石矿物的风化与侵蚀相关,Cu、Zn和Pb主要受工业、金属冶炼、矿物开采等人类活动的影响,而Cd和As则主要来源于农业生产活动.长江重庆段和汉江区别于长江流域其它河段,表明水体受人类活动影响比较严重,但长江流域重金属浓度水平整体低于世界其它重工业和农业发达区域的河流.由于长江径流量巨大,Cu、Zn、Pb、Cd与As的入海通量是长江口及其近海重金属收支与循环的重要一环,并可能对河口生态环境产生深远的生态学效应.     

黄海近岸大气降水中磷溶解度及其影响因素

于2020年6~9月在黄海近岸城市青岛采集31场降水69个样品,分析其中总磷（TP）、溶解态总磷（DTP）及溶解态无机磷（DIP）和有机磷（DOP）,探讨P浓度和溶解度的变化特征及其影响因素.降水中TP浓度为（6.2±1.0）μg/L,DTP浓度为（3.8±0.6）μg/L,P溶解度为（64.8±18.0）%.DTP中以DIP为主,其贡献为（56.5±21.6）%.降水中TP和DTP与降水量呈负幂指数关系,TP清除指数大于DTP.降水量<10mm时,降水对气溶胶P的清除和稀释作用显著影响降水中P浓度,但降水量>40mm时,这种作用对P浓度的影响不大.降水对气溶胶P的清除作用以云下清除为主,占总清除效率的70%~85%.酸化作用显著促进降水中颗粒态P溶解,且无机P溶解效率高于有机P.对降雨量<5mm及>30mm降水,pH值是影响P溶解度的主要因素,降水量和气团来源对P溶解度也有一定影响.当pH值相近时,降水量越大,P溶解度越高;当pH值相近且降水量<5mm时,海洋源贡献越大,P溶解度越高.对降水量5~30mm的降水,P溶解度受到降水量、pH值及气团来源等因素的共同影响.     

磁性活性炭强化SBR脱氮除磷及微生物种群分析

为了提高传统活性污泥法脱氮除磷效率,改善污泥易膨胀等问题,在序批式活性污泥反应器（SBR）中,投加140目1.00g/L的磁性活性炭构建磁性炭基活性污泥系统（1^#）,同时,以不投加任何材料（单独活性污泥系统）为对照组（0^#）,研究磁性活性炭对活性污泥系统除污性能和主要微生物种群结构组成的影响,探讨了磁性活性炭强化活性污泥系统脱氮除磷机理.结果表明：1^#对TN和TP的平均去除率分别为68.59%和78.25%;而0^#对于TN和TP的平均去除率则为53.17%与54.10%,1^#出水NO₃^--N浓度平均降低了7.03mg/L,两系统对NH₄⁺-N和COD的去除效率差别不大,均在95.00%以上.典型周期内1^#中TN、NH₄⁺-N、TP、COD的下降速率快于0^#;0^#同步硝化反硝化效率为60.31%,反硝化速率为4.44mg/（L·h）,1^#同步硝化反硝化效率为80.74%,反硝化速率为6.13mg/（L·h）,实验组1^#脱氮速率明显快于空白对照组0^#.高通量测序结果表明,1^#内污泥的优势菌门为Saccharibacteria（38.74%）、Proteobacteria（22.52%）、Actinobacteria（18.54%）和Chloroflexi（8.40%）.此外,与0^#相比,1^#引发污泥膨胀密切相关的Actinobacteria菌门的微生物相对丰度显著下降;与脱氮除磷功能相关的Micropruina、Shinella、norank_f_Anaerolineaceae和norank_f_Xanthomonadaceae 4种菌属的相对丰度都明显上升.SBR系统中加载一定量的磁性活性炭既能抑制引起污泥膨胀微生物的生长,又能利于脱氮除磷微生物的富集,整个污泥系统表现出良好的稳定性和脱氮除磷性能.     

Methylopila sp.SD-1与大豆联合修复苯磺隆污染土壤

分离得到1株苯磺隆降解菌株SD-1,根据表型、生理生化特征及16S rRNA基因序列分析,将其鉴定为Methylopila sp.SD-1,为首次报道能够降解苯磺隆的Methylopila属菌株,其在4d内完全降解50mg/L苯磺隆,最适降解温度、pH值分别为30℃和7.0,降解中间产物对大豆的毒性显著降低.大豆根系分泌物能促进菌株SD-1的生长,培养5d,菌株SD-1的数量由1.0×10⁷CFU/mL增至6.7×10⁷CFU/mL.分泌物中含有16种氨基酸,菌株SD-1对其中的Asp、Glu和Phe表现出明显的趋化性.接种菌悬液至苯磺隆污染土壤（3mg/kg）并种植大豆幼苗,培养4d,菌株SD-1依赖趋化性向大豆根系运动并定殖,存活率提高,根际土壤中苯磺隆的降解率相较于未种植大豆的处理提高36.0%.     

汞污染地块风险全生命周期管控技术体系研究

风险全周期管理是推进汞污染地块风险管控,有效实现地块安全可控的重要方式.在《关于汞的水俣公约》全球履约背景下,为有效提升汞污染地块的风险预防与管控能力,该文对汞污染地块风险管控技术体系进行了深入研究.在深入分析污染地块健康风险全生命周期特征的基础上,围绕地块风险源头-暴露途径-环境受体3个核心风险要素,并结合国内外技术研发与工程示范经验,构建出适用于此类污染地块的风险全周期分类管控技术体系.该体系根据土壤与地下水风险管控标准评价地块污染水平,并结合地块敏感目标和暴露途径等暴露情景对地块进行分类管控决策.通过对工程修复、风险管控、制度控制等进行多技术有机耦合,可实现对汞污染地块全方位、多角度、系统化的风险管理,即在风险产生、风险发展与风险消褪的各个环节,分别施以源头预防、过程控制及长期管理措施,有效遏制地块新增风险的基础上,实现污染地块风险的安全可控.该技术体系存在如下特征:1)基于风险的管理决策可以反映地块管理的科学内涵;2)分类风险管控策略可以有效节约成本,实现最大的管控净效益;3)以全生命周期管理为基本理念,实现“源头-过程-末端”的全流程风险控制.     

Mechanisms of Pb(II) coprecipitation with natrojarosite and its behavior during acid dissolution

Lead (Pb) coprecipitation with jarosite is common in natural and engineered environments, such as acid mine drainage (AMD) sites and hydrometallurgical industry. Despite the high relevance for environmental impact, few studies have examined the exact interaction of Pb with jarosite and the dissolution behavior of each phase. In the present work, we demonstrate that Pb mainly interacts with jarosite in four modes, namely incorporation, occlusion, physically mixing, and chemically mixing. For comparison, the four modes of Pb-bearing natrojarosite were synthesized and characterized separately. Batch dissolution experiments were undertaken on these synthetic Pb-bearing natrojarosites under pH 2 to simulate the AMD environments. The introduction of Pb decreases the final Fe releasing efficiency of jarosite-type compounds from 18.18% to 3.45%-5.01%, showing a remarkable inhibition of their dissolution. For Pb releasing behavior, PbSO₄ dissolves in preference to Pb-substituted natrojarosite, i.e., (Na, Pb)-jarosite, which primarily results in the sharp increase of Pb releasing concentration (> 40 mg/L). PbSO₄ occlusion by jarosite-type compounds can significantly reduce the release of Pb. The results of this study could provide useful information regarding Fe and Pb cycling in acidic natural and engineered environments.     

Response of PM2.5-bound elemental species to emission variations and associated health risk assessment during the COVID-19 pandemic in a coastal megacity

The coronavirus (COVID-19) pandemic is disrupting the world from many aspects. In this study, the impact of emission variations on PM_2.5-bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic. Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown. After the lockdown, they rebounded rapidly, of which V and Ni even exceeded the levels before the lockdown, suggesting the recovery of both inland and shipping activities. Five sources were identified based on receptor modeling. Coal combustion accounted for more than 70% of the measured elemental concentrations before and during the lockdown. Shipping emissions, fugitive/mineral dust, and waste incineration all showed elevated contributions after the lockdown. The total non-carcinogenic risk (HQ) for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ. Whereas, the total carcinogenic risk (TR) for adults was above the acceptable level and much higher than that for children. Waste incineration was the largest contributor to HQ, while manufacture processing and coal combustion were the main sources of TR. Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk. From the perspective of health effects, priorities of control measures should be given to waste incineration, manufacture processing, and coal combustion. A balanced way should be reached between both lowering the levels of air pollutants and their health risks.     

白茅海潮滩重金属空间分布特征及生态风险评价

本研究于2020年8月测定了白茅海潮滩表层、次表层（50 cm深）沉积物及间隙水、排放废水中9种重金属（Zn、Cr、Pb、As、Cu、Cd、Ni、Fe、Mn）的含量,利用潜在生态危害指数法以及相关性分析法,结合沉积物粒度特征和TOC含量对白茅海潮滩重金属的分布特征、相关关系和污染风险进行了分析。结果表明,调查区表层沉积物以砂为主,粘土和粉砂含量极少,TOC平均含量为0.031%,重金属含量为Fe>Mn>Zn>Cr>Pb>As>Ni>Cu>Cd。沿岸方向上,P1剖面某些重金属含量高于整个调查区平均含量,出现富集趋势。表层沉积物中的重金属在垂岸方向未表现出明显的分布规律。不同深度沉积物Pb、Zn、Cu、Cr、As、Cd含量均低于国家海洋沉积物I类标准值。间隙水中重金属含量为Mn>Fe>Zn>As>Ni>Cu>Pb>Cr>Cd,Cr、Fe、Mn在不同介质中含量差异较大。调查区氧化还原类金属对重金属含量影响较大,粒度和TOC对重金属含量影响较小。调查区综合潜在生态风险指数ERI为113.03,表现为轻微潜在生态危害。各重金属潜在生态污染程度为Cd>As>Pb>Cu>Zn>Cr。Cd为调查区表层沉积物中的主要污染因子,应列为白茅海潮滩优先控制的重金属。     

入境船舶压载水潜在致病菌组成及影响因素研究

船舶压载水直接促进了地理性隔离海域之间的水体交换,可作为潜在致病菌迁移扩散的媒介。本文以采集到的25艘入境船舶的压载水样品为研究对象,采用高通量测序技术对潜在致病菌群落组成和影响因素进行了初步解析。结果表明:变形菌（Proteobacteria）、拟杆菌（Bacteroidetes）和放线菌（Actinobacteria）为压载水中的优势菌门。船舶压载水中共检出36个潜在致病菌属和19个潜在致病菌种。痤疮丙酸杆菌（Cutibacterium acnes）、大肠埃希氏杆菌（Escherichia coli）和表皮葡萄球菌（Staphylococcus epidermidis）为压载水中最普遍的潜在致病菌,检出率超过50%。置换和未置换压载水中潜在致病菌的种类数量和丰度并无显著差异。此外,压载水中的潜在致病菌与磷酸盐及大肠埃希氏杆菌呈显著正相关性,表明其可能与近岸的人类活动有关。综上所述,相关部门应当对船舶压载水加强管理,以降低潜在致病菌的入侵扩散风险。     

Removal of refractory organics and heavy metals in landfill leachate concentrate by peroxi-coagulation process

Landfill leachate is a complex effluent and it is difficult to deal with. Electrochemical methods have been considered as a promising alternative technology for treatment of landfill leachate with refractory organic contaminants and heavy metals. Peroxi-coagulation (PC) process with iron anode and modified graphite felt cathode was developed for efficient landfill leachate concentrate treatment. Compared to electro-Fenton (EF) and electrocoagulation (EC) processes, the PC process was more cost-effective due to the combined action of ^•OH oxidation and iron hydroxides coagulation. A maximal TOC removal of 77.2% ± 1.4% was obtained after 360 min at initial pH = 5.0 and current density of 10 mA/cm². After the PC process, concentrations of all seven heavy metals in the final effluents were below the allowable emission limits given by the present regulatory standards. The method preference for heavy metal removal was PC > EC > EF. Based on the three-dimensional fluorescence spectroscopy coupled with regional integration analysis during the PC treatment, the florescence peaks of both humic acids and fulvic acids disappeared after treatment for 360 min. Decreasing trends were observed in the fluorescent regional standard volumes for aromatic protein I (31.4%), aromatic protein II (63.7%), fulvic acid-like (69.5%), soluble microbial by-product-like (75%) and humic acid-like regions (76.3%). The results indicate that comparing to the EF and EC process, the PC process provide a promising and more cost-effective alternative for the treatment of landfill leachate concentrate.