城市污泥人工土壤中重金属生物有效性及综合毒性研究

以城市污泥为主要成分,添加不同比例的单一辅料(草炭、磷矿粉、粉煤灰)配成不同的城市污泥人工土壤,研究各配比人工土壤中重金属生物有效性和综合毒性,并揭示人工土壤中重金属向黑麦草的动态迁移.结果表明:各配比人工土壤中重金属生物有效性和综合毒性均较污泥明显下降;当粉煤灰添加比例为20%时,人工土壤中Cu、Zn、Pb、Ni生物有效态含量下降最多,分别为28.75%、36.09%、34.85%和36.52%,此时,重金属综合毒性指数降幅最大,为2.7×10-3;与污泥相比,各配比人工土壤中重金属向黑麦草的迁移能力显著降低,非线性回归分析显示黑麦草中重金属富集浓度与人工土壤中重金属的生物有效态含量间存在正幂函数关系.     

添加不同塑料与污泥混合热解对生物炭中重金属的影响

利用高温管式炉开展城市污泥（SS）与四种塑料（PE、PP、PS和PVC）混合热解实验,分别得到四种生物炭（SSC_PE、SSC_PP、SSC_PS和SSC_PVC）,研究了生物炭中重金属（Cr、Mn、Ni、Cu、Zn、As、Cd和Pb）含量、残余率、BCR形态和TCLP浸出毒性特征,并开展潜在生态风险评估。结果表明,添加不同塑料与污泥混合热解能够降低除Cd以外重金属的残余率。与污泥单独热解所得生物炭（SSC）相比,添加PE、PP和PS能够促进生物炭中的重金属向相对稳定态（F3+F4）转化,实现固化稳定;添加PVC仅对生物炭中Cr和As有固化稳定作用,对其他重金属有明显活化作用。四种生物炭中的重金属浸出量低于GB5085.3-2007浸出毒性鉴别标准规定的限值,生态风险均明显地降低至轻微风险水平,表明添加PE、PP、PS和PVC与污泥混合热解所得生物炭的应用不会带来新的环境风险,这为污泥与废塑料协同处置工艺提供了良好的理论支撑。     

Safety Issue of Changed Nanotoxicity of Zinc Oxide Nanoparticles in the Multicomponent System

When nanomaterials are exposed to complex systems, such as food, they may cause significant changes in physical and chemical properties and even toxicity. The toxicity evaluation of complex systems is urgent. Unfortunately, so far, there is no database established about the toxicity changes of nanoparticles in composite systems. In this paper, the changes and toxicity mechanism of zinc oxide nanoparticles (ZnO NPs) in a composite system are studied. The results show that the dissolution of zinc ions (Zn²⁺) in acidic systems (vitamin C, tartaric acid, or citric acid) increases the toxicity of ZnO NPs. However, the toxicity of ZnO NPs is reduced by the complexation effect with Zn²⁺ in phosphoric acid, phosphate, and glutathione systems. The influence of titanium dioxide nanoparticles (TiO₂ NPs) on the toxicity of ZnO NPs depends on size and surface properties. In brief, the intracellular Zn²⁺ homeostasis level is the decisive factor in determining the toxicity change in complex systems. The results indicate that the toxicity changes are very different in combined systems, which may have potential food safety issues, especially for unstable nanoparticles.     

Enhanced Physiological Stability and Long‐Term Toxicity/Biodegradation In Vitro/In Vivo of Monodispersed Glycerolphosphate‐Functionalized Bioactive Glass Nanoparticles

Monodispersed bioactive glass nanoparticles (BGNs) have received much attention in various biomedical applications such as tissue regeneration, drug/gene delivery, bioimaging, and cancer therapy. However, the poor dispersion stability of BGNs in a physiological environment has limited their wide biomedical applications. The long‐term in vitro/in vivo toxicity and biodegradation of BGNs are also not clear. Monodispersed glycerolphosphate‐functionalized BGNs (GP‐BGN) are synthesized and their stability under physiological environment in vitro, and long‐term biodegradation behavior in vitro and in vivo are investigated herein. GP‐BGN shows significantly enhanced particles stability in physiological environment, good hemocompatibility and cellular biocompatibility, as well as high cellular uptake ability. GP‐BGN also exhibits long‐term biodegradation behavior in vitro/in vivo and negligible biotoxicity (tissue and blood toxicity). This study demonstrates that monodispersed surface‐functionalized BGNs could be used as biocompatible and biodegradable nanomaterials for long‐term safe bioimaging and disease therapy.     

Influence of zinc stannate and graphene hybrids on reducing the toxic gases and fire hazards during epoxy resin combustion

Spinel zinc stannate (Zn₂SnO₄, ZS) was successfully synthesized by a simple hydrothermal route, and graphene(G) was used as the carrier to form graphene‐zinc stannate (G‐ZS) hybrids. The resulted G‐Zn₂SnO₄ (G‐ZS) was incorporated to epoxy resin for the purpose of reducing the toxicity hazards during combustion. Toxic gas analyzer results showed that the ZS hybrids possess high efficiency on reducing the generation of NOx, HCN, and CO. Cone calorimeter results of the G‐ZS/EP composites showed about 40% decrease on peak heat release rate compared with pristine EP which meant better fire performance. Also, TG‐IR technology was used to further investigate the gases release during the EP decomposition process. Particularly, the CO release had decreased about 80% than pure EP. This work constructs a new strategy to make a binary metal oxides system which would be efficient in reducing the toxic gases during polymer combustion. Besides, a proper bridge‐effect is proposed to illustrate the proper mechanism.     

Development of classification models for predicting chronic toxicity of chemicals to Daphnia magna and Pseudokirchneriella subcapitata

Both the acute toxicity and chronic toxicity data on aquatic organisms are indispensable parameters in the ecological risk assessment priority chemical screening process (e.g. persistent, bioaccumulative and toxic chemicals). However, most of the present modelling actions are focused on developing predictive models for the acute toxicity of chemicals to aquatic organisms. As regards chronic aquatic toxicity, considerable work is needed. The major objective of the present study was to construct in silico models for predicting chronic toxicity data for Daphnia magna and Pseudokirchneriella subcapitata. In the modelling, a set of chronic toxicity data was collected for D. magna (21 days no observed effect concentration (NOEC)) and P. subcapitata (72 h NOEC), respectively. Then, binary classification models were developed for D. magna and P. subcapitata by employing the k-nearest neighbour method (k-NN). The model assessment results indicated that the obtained optimum models had high accuracy, sensitivity and specificity. The model application domain was characterized by the Euclidean distance-based method. In the future, the data gap for other chemicals within the application domain on their chronic toxicity for D. magna and P. subcapitata could be filled using the models developed here.     

FTIR结合热重(差热)技术对红壤地区大豆铝毒害的鉴定

采用傅里叶变换红外光谱法(FTIR), 结合热重和差热分析对不同铝浓度下的大豆根系进行了研究。结果表明, 在60和90 mg·L-1的铝液处理下,大豆根系的铝含量较高,达到显著铝毒害水平。在相同的波数范围内,不同铝浓度下其红外谱图的性状、波数及吸收峰的数目有所不同,3 300, 2 930, 1 542和721 cm-1下的吸收峰可作为鉴定大豆铝毒害的特征峰。3 300和2 930 cm-1特征峰在高浓度(60和90 mg·L-1)的铝毒害下明显高于其他浓度特征峰,1 542 cm-1的酰胺Ⅱ带特征峰在90 mg·L-1下没有显现, 721 cm-1吸收峰带却在Al 60和90 mg·L-1浓度下有表现。不同铝浓度下的热重(TG)和差热(DT)曲线在400～500 ℃温度范围内差别最大,TG曲线在大于30 mg·L-1的铝处理下与空白相比的质量损失减少,表明铝处理可能使根系木质化加重,产生难以燃烧的物质;DT曲线在60和90 mg·L-1的铝处理下出现双峰,可作为大豆铝毒害的鉴定标志之一。由此,FTIR结合热重(差热)技术可以用来鉴定红壤地区大豆的铝毒害。     

水毒性的光生物法检测与评价

本文提出一种新的光生物法对水的毒性进行检测，文中介绍了测试原理、测试装置及实测数据．根据实测数据，提出水的毒性分为“无毒”、“微毒”、“中等毒性”及“剧毒”四级以实现半定量评价．     

水毒性的光生物法检测与评价

本文提出一种新的光生物法对水的毒性进行检测,文中介绍了测试原理、测试装置及实测数据。根据实测数据,提出水的毒性分为“无毒”、“微毒”、“中等毒性”及“剧毒”四级以实现半定量评价。     

Tin in pharmacy and nutrition

The occurrence of tin in plants, animals and humans is discussed in relation to its abundance in the lithosphere and hydrosphere and the range of different tin(II) and tin(IV) complexes formed. A reasoned consideration of the essentiality or otherwise of tin for living species is given and it is concluded that tin is beneficial even if not yet proved to be an essential element. After reference to the chemistry of tin compounds, there is a detailed discussion of their toxicity in animals and humans. Feasible routes for tin intake and uptake into humans are described. The use of tin pharmaceuticals in previous and current times is reviewed and areas for which they are currently permitted for use in man as dentifrices and mouth washes, as radiopharmaceuticals and for the treatment of jaundiced newborns are described. A detailed review of tin-coating antitumour agents as representative tin pharmaceuticals is given. Finally, a range of tin compounds having other specific pharmaceutical applications and which are currently being investigated are listed.