中国北方某市城市绿地土壤重金属空间分布特征、污染评价及来源解析

为掌握北方某市城市中心区绿地土壤环境状况,对其中心区城市绿地土壤重金属（Cd、Hg、As、Pb、Cu、Cr、Zn和Ni）的空间分布、来源及污染现状进行分析和评价.结果表明,该市中心区的城市绿地土壤环境质量整体良好.土壤重金属Cd、Hg、As、Pb、Cr、Cu、Zn和Ni的含量均值分别为：0.172、0.202、9.02、34.7、57.0、31.2、85.7以及26.3mg·kg^-1.Cd、Hg、Pb和Zn平均含量均超过同为北方地区的京津唐土壤背景值.所有点位各项重金属含量均不超过国家建设用地土壤污染风险管控标准的污染风险筛选值.空间上,As、Cr和Ni含量高值出现于西北部;Cd和Zn含量高值出现于东北部;Hg、Pb和Cu的高值区集中在城市核心区.对于不同土地利用类型土壤,Cd、Zn和Ni在企业绿地土壤中含量显著高于其他元素,Hg、Pb和Cu等在公园绿地和居民绿地土壤中含量较高.土壤污染评价结果表明,97.2%的样点内梅罗综合污染指数小于1,为清洁土壤;所有样点潜在生态风险指数均小于80,属轻微生态风险水平.多元统计分析表明,Cu、Pb和Hg为人为源,与古建筑保护的彩绘以及对古树保护采用杀虫剂有关;Cr为自然源,可能来源于土壤母质和地球化学过程;Cd、Zn、Ni和As为混合来源,部分可能来源于人类活动和工业生产,另一部分来源于岩石的风化和土壤母质等.利用受体模型对超标元素进行来源定量解析,Cd按来源贡献率高低依次为源2（占46.1%）、源3（占33.1%）、源1（17.7%）和其他源（占3.1%）;Cu源贡献率主要为源1（占93.0%）;Zn源贡献率依次为源1（占52.4%）、源3（占24.2%）、源2（占20.0%）以及其他源（占3.4%）;Ni源贡献率依次为源1（占56.3%）、源2（占37.8%）以及源3（占5.8%）.推测源1和源3为人为源,源2为自然来源.     

基于二次铝灰的地聚反应稳固化垃圾飞灰

基于工业生产铝过程中回收的二次铝灰（SAD）的地质聚合反应,提出了一种稳固化城市生活垃圾焚烧飞灰（MSWIFA）的新方法,分析硅铝物质的量之比对飞灰中重金属浸出浓度及地聚物固化体力学性能的影响规律.结果表明,当硅铝物质的量之比小于2.5时,二次铝灰-SiO₂基固化体与偏高岭土-SiO₂基固化体中的重金属浸出浓度均随着硅铝物质的量之比的增加而逐渐降低,2种固化体的抗压强度随着硅铝物质的量之比的增加而增加;硅铝物质的量之比达到2.5时,重金属的浸出浓度与固化体的抗压强度均趋于稳定.XRD分析结果显示,偏高岭土-SiO₂基固化体中聚合物的种类与数量均略高于二次铝灰-SiO₂基固化体.但从重金属的浸出浓度与固化体的抗压强度来看,2类固化体对飞灰中重金属的稳固化效果的差别很小,二次铝灰加上部分硅基材料可以作为偏高岭土的替代品,用于稳固化飞灰重金属的地质聚合反应中.二次铝灰-SiO₂基固化体的抗压强度达到13.65MPa,具备一定的力学性能,可用于部分特定的建筑材料.     

3D打印技术在固体废弃物资源循环中的应用

打印材料是限制3D打印技术发展和推广应用的瓶颈问题,目前已经发现部分固体废弃物与3D打印的契合度很高,可以用于制备3D打印材料.本文综述了4类可以用于3D打印的固体废弃物,包括硅铝基废弃物、农林废弃物、废旧塑料和废旧金属,着重讨论了这4类废弃物制备3D打印材料的方法以及废弃物的添加对原打印材料造成的影响,同时分析了当前废弃物制备3D打印材料需要解决的问题,并对废弃物基3D打印材料的发展趋势进行了展望.     

北京大气PM2.5载带金属浓度、来源及健康风险的城郊差异

为探究北京地区大气PM_2.5载带金属在城区和郊区污染特征、来源及其健康风险的差异,于2017年6~11月采集海淀和大兴两地的PM_2.5日样本,分析PM_2.5及其载带的13种金属浓度.利用PMF源解析方法对13种金属元素来源进行分析,并采用健康风险评价方法对其中9种金属的健康危害进行评估.结果表明,城区PM_2.5及Cr、Co、Mn和Ni等10种金属浓度与郊区均有显著差异（P<0.05）.源解析结果发现,城区和郊区均可解释为4个源,但来源略有不同,占比亦有差异.城区的为机动车源（51.2%）、燃煤来源（19.1%）、扬尘来源（19.3%）和燃油来源（10.4%）;郊区的为机动车源（47.9%）、燃煤来源（22.6%）、扬尘来源（20.2%）和电镀来源（9.3%）.健康风险评价结果表明,城郊各金属HQ值均小于1,均不存在非致癌风险.城区中Ni和Pb,郊区中Cd、Co、Ni和Pb可忽略致癌风险,而城区的As（2.77×10^-5）、Cd（2×10^-6）、Co（1.76×10^-6）和Cr（Ⅵ）（7.88×10^-6）,郊区的As（8.34×10^-6）和Cr（Ⅵ）（4.94×10^-6）的R值介于10^-6与10^-4之间,具有一定的致癌风险.     

Co-metabolic and biochar-promoted biodegradation of mixed PAHs by highly efficient microbial consortium QY1

Polycyclic aromatic hydrocarbons (PAHs), typical representatives of the persistent organic pollutants (POPs), have become ubiquitous in the environment. In this study, a novel microbial consortium QY1 that performed outstanding PAHs-degrading capacity has been enriched. The degradation characteristics of single and mixed PAHs treated with QY1 were studied, and the effect of biochar on biodegradation of mixed PAHs and the potential of biochar in PAHs-heavy metal combined pollution bioremediation were also investigated. Results showed that, in single substrate system, QY1 degraded 94.5% of 500 mg/L phenanthrene (PHE) and 17.8% of 10 mg/L pyrene (PYR) after 7 days, while in PHE-PYR mixture system, the biodegradation efficiencies of PHE (500 mg/L) and PYR (10 mg/L) reached 94.0% and 96.2%, respectively, since PHE served as co-metabolic substrate to have significantly improved PYR biodegradation. Notably, with the cooperation of biochar, the biodegradations of PHE and PYR were greatly accelerated. Further, biochar could reduce the adverse impact of heavy metals (Cd²⁺, Cu²⁺, Cr₂O₇^2?) on PYR biodegradation remarkably. The sequencing analysis revealed that Methylobacterium, Burkholderia and Stenotrophomonas were the dominant genera of QY1 in almost all treatments, indicating that these genera might play key roles in PAHs biodegradation. Overall, this study provided new insights into the efficient bioremediation of PAHs-contaminated site.     

The concentration and probabilistic risk assessment of potentially toxic elements in fillets of silver pomfret (Pampus argenteus): A global systematic review and meta-analysis

The contamination of fish type products such as silver pomfret fish fillets by potentially toxic elements (PTEs) has raised global health concerns. Related studies regarding the concentration of PTEs in fillets of silver pomfret fish were retrieved among some international databases such as Scopus, PubMed and Embase between 1 January 1983 and 10 March 2020. The pooled (mean) concentration of PTEs in fillets of silver pomfret fish was meta-analyzed with the aid of a random-effect model (REM). Also, the non-carcinogenic risk was estimated via calculating the 95th percentile of the total target hazard quotient (TTHQ). The meta-analysis of 21 articles (containing 25 studies or data reports) indicated that the ranking of PTEs in fillets of silver pomfret fish was Fe (11,414.81 µg/kg wet weight, ww) > Zn (6055.72 µg/kg ww) > Cr (1825.79 µg/kg ww) > Pb (1486.44 µg/kg ww) > Se (1053.47 µg/kg ww) > Cd (992.50 µg/kg ww) > Ni (745.23 µg/kg ww) > Cu (669.71 µg/kg ww) > total As (408.24 µg/kg ww) > Co (87.03 µg/kg ww) > methyl Hg (46.58 µg/kg ww). The rank order of health risk assessment by country based on the TTHQ for adult consumers was Malaysia (2.500) > Bangladesh (0.886) > Iran (0.144) > China (0.045) > Pakistan (0.020) > India (0.015), while the corresponding values for child consumers was Malaysia (11.790) > Bangladesh (4.146) > Iran (0.675) > China (0.206) > Pakistan (0.096) > India (0.077). The adult consumers in Malaysia and children in Malaysia and Bangladesh were at considerable non-carcinogenic risk. Therefore, following the recommended control plans in order to reduce the health risk associated with the ingestion of PTEs via consumption of silver pomfret fish fillets is crucial.     

Estimation of atmospheric trace metal emissions in Vilnius City, Lithuania, using vertical concentration gradient and road tunnel measurement data

A new approach for the estimation of trace metal emissions in Vilnius city was implemented, using vertical concentration profiles in the urban boundary layer and road tunnel measurement data. Heavy metal concentrations were examined in fine and coarse particle fractions using a virtual impactor (cut-off size diameter 2.5 μm). Negative vertical concentration gradients were obtained for all metals (Ba, Pb, V, Sb, Zn) and both fractions. It was estimated that the vertical concentration gradient was formed due to emissions from an area of about 12 km². Road tunnel measurements indicated that trace metal concentrations on fine particles were lower than those on coarse particles, which suggested that re-emitted road dust was highly enriched in trace metal due to historic emissions within the tunnel. Emission rates of different pollutants in the road tunnel were calculated using pollutant concentration differences at the tunnel entrance and exit and traffic flow data. Heavy metal emission rates from the area of Vilnius city were estimated using the vertical gradient of heavy metal concentrations and the coefficient of turbulent mixing, as derived from meteorological measurement data. The emission values calculated by the two different methods coincided reasonably well, which indicated that the main source of airborne trace metals in Vilnius city is traffic. The potential of the vertical concentration gradient method for the direct estimation of urban heavy metal emissions was demonstrated.     

郑州市典型污染过程PM1中重金属浓度、来源及健康风险评估

颗粒物中重金属元素可对人体健康造成不利影响,粒径越小危害越大.利用在线重金属观测仪于2021年1月7～25日在郑州市连续测定PM₁中Al、 Si、 K、 Ca、 V、 Cr、 Mn、 Fe、 Ni、 Cu、 Zn、 As、 Se、 Ba、 Pb和Cd共16种重金属元素.结果表明,观测期间ρ（K）的浓度最高(0.62μg·m^-3).根据污染物浓度和气象特征,将观测期间划分为清洁日、沙尘日和霾日.大气PM₁中重金属污染特征和健康风险评价在不同污染过程下的贡献不同.利用美国EPA健康风险评价法评估重金属的健康风险,采用富集因子法和正定矩阵因子模型（PMF）解析重金属来源,并利用浓度权重轨迹分析法（CWT）和后向轨迹法对传输的影响进行评估.结果表明在不同污染过程下Zn、 As、 Se、 Pb和Cd的富集因子超过100,均受人类活动影响较大.在观测期间重金属主要来源为工业源、燃煤/生物质源、机动车源和扬尘源.将健康风险结果代入PMF分析发现,在清洁日、沙尘日和霾日期间工业源是致癌与非致癌健康风险的主要贡献源,且本地区PM_...     

Multi-factor principle for electrolyte additive molecule design for facilitating the development of electrolyte chemistry

When I read the paper"Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries"from Prof. Jianmin Ma's group, which was published in Science Bulletin (doi.org/10.1016/j.scib.2020.09.018), I felt excited as presented a multi-factor principle for applying potassium perfluorinated sulfonates to suppress the dendrite growth and protect the cathode from the viewpoint of electrolyte additives. The effects of these additives are revealed through experimental results, molecular dynamics simulations and first-principle calculations. Specifically, it involves the influence of additives on Li+ solvation structure, solid electrolyte interphase (SEI), Li growth and nucleation. Following the guidance of the multi-factor principle, every part of the additive molecule should be utilized to regulate electrolytes. This multi-factor principle for electrolyte additive molecule design (EAMD) offers a unique insight on understanding the electrochemical behavior of ion-type electrolyte additives on both the Li metal anode and high-voltage cathode. In these regards, I would be delighted to write a highlight for this innovative work and, hopefully, it may raise more interest in the areas of electrolyte additives.     

白银矿区土壤重金属及可培养细菌重金属耐受性研究

对白银矿区土壤重金属进行分析研究,分离、筛选和鉴定了受污染土壤中的可培养细菌,并考察其对土壤中重金属胁迫的耐受性。结果表明：白银矿区王岘镇尾渣堆和东大沟河沟土壤重金属污染Pb＞Zn＞Cu;从污染最严重的土壤中分离、筛选出砖红色微杆菌（Microbacterium testaceum）、特基拉芽孢杆菌（Bacillus tequilensis）和解单端孢菌素微杆菌（Microbacterium trichothecenolyticum）3种细菌,其中菌株M1（Microbacterium testaceum）对Pb、Zn、Cu、Cd的胁迫具有明显的耐受性。