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561.
Yishan Lin Yanling He Zhuo Meng Shucheng Yang 《Frontiers of Environmental Science & Engineering》2008,2(2):241-246
The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater. However, acetic acid can also be produced from methanol theoretically, which may probably result in an abrupt pH drop and deteriorate the anaerobic process. Therefore, it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater. In this study, an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated. The chemical oxygen demand (COD), acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity. The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops. Volatile fatty acids accumulation was not observed even at strong shock loadings. The microorganisms in the sludge at the end of the test became homogeneous in morphology, which were mainly spherical or spheroidal in shape. 相似文献
562.
563.
Ya-meng Wen Ling-yu Meng Shi-tao Liu Cheng-mei Zhu Ying-jie Liu 《Chemistry and Ecology》2017,33(9):883-892
Increasing studies suggest that insecticides are one of the plant stress elements that affect plant growth and productivity by interfering with cell metabolic and biochemical activities. Here, we show that the application of commonly used pesticides omethoate and cypermethrin on maize (Zea mays L. cv. Luyu 9) seedling leaves resulted in adverse effects on leaf ultrastructure changes under laboratory conditions. Electron microscopic studies reveal that the topical application of organophosphorus insecticide omethoate causes direct injury of leaf ultrastructures including cell wall breakdown of abaxial epidermis cells, inner cells, stomata guard cells; degradation of mitochondrial membrane, and chloroplast envelope membrane; and abnormal changes of lamella arrangement of chloroplast. And the topical application of cypermethrin insecticide causes plasmolysis of cells of the adaxial epidermis, mitochondrial cristae are degraded, and loosen arranged lamella of amyloplasts. All these changes indicated that omethoate and cypermethrin are stress factors that caused adverse effects on plant ultrastructures and biochemical molecules. 相似文献
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565.
Meng Fanao Liang Xiujuan Xiao Changlai Wang Ge 《Environmental geochemistry and health》2022,44(7):2215-2233
Environmental Geochemistry and Health - Mathematical statistics, correlation analysis, Piper and Gibbs diagrams, and geographic information system- based multi-criteria decision analysis were used... 相似文献
566.
选用海伦黑土、咸宁棕红壤和长武黑垆土这3种土壤,分别设置4组不同含量配比的Pb和Cd复合处理,进行为期5个月的小麦种植(郑麦9023号)盆栽试验,结合小麦植株各部位Pb和Cd含量,分析3种土壤-小麦体系中Pb和Cd交互作用对小麦富集转运重金属的影响.结果表明,低pH棕红壤水溶态Cd和Pb含量最高,且土壤颗粒表面Pb和Cd交互作用显著,高有机质黑土及高碳酸钙含量的黑垆土中Cd和Pb活性较低.3种土壤中黑垆土种植小麦的株高和干重表现最差,但Pb和Cd复合作用使其株高较对照增加了2.68~8.49 cm, Pb和Cd交互作用对黑土中小麦的株高和干重影响最小,但抑制了棕红壤中小麦生长.3种土壤-小麦体系的Pb和Cd交互作用差异较大,棕红壤中Pb和Cd间存在协同作用,125 mg·kg-1和250 mg·kg-1Pb处理下棕红壤种植的小麦籽粒Pb含量随Cd添加量升高分别显著增加73.2%和19.1%;黑土中Pb和Cd间存在拮抗作用,0.3 mg·kg-1和0.6 mg·kg-1 Cd处理下黑土中小麦籽粒Cd含... 相似文献
567.
568.
铬是电镀废水处理中的重点之一.金属铬几乎无毒,二价铬一般认为是无毒的,其余的铬化合物,在一定浓度下,都是有不同毒性的.三价铬的毒性约是六价铬的1/100,是人体必须有的微量元素.六价铬有致癌作用,对皮肤有刺激和过敏作用.电镀废水中主要含有六价铬化合物.文章介绍了含铬电镀废水的来源及含铬电镀废水处理工艺分类,重点介绍化学沉淀法处理电镀废水的应用. 相似文献
569.
570.