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271.
Chemical speciation and extractability of Zn,Cu and Cd in two contrasting biosolids-amended clay soils 总被引:13,自引:0,他引:13
An incubation experiment was conducted to study the chemical speciation and extractability of three heavy metals in two contrasting biosolids-amended clay soils. One was a paddy soil of pH 7.8 and the other was a red soil of pH 4.7 collected from a fallow field. Anaerobically digested biosolids were mixed with each of the two soils at three rates: 20, 40 and 60 g kg(-1) soil (DM basis), and unamended controls were also prepared. The biosolids-amended and control soils were incubated at 70% of water holding capacity at 25 degrees C for 50 days. Separate subsamples were extracted with three single extractants and a three-step sequential extraction procedure representing acetic acid (HOAc)-soluble, reducible and oxidisable fractions to investigate the extractability and speciation of the heavy metals. As would be expected, there were good relationships between biosolids application rate and metal concentrations in the biosolids-amended soils. The three heavy metals had different extractabilities and chemical speciation in the two biosolids-amended soils. Ethylene diamine tetraacetic acid extracted more Cu, Zn and Cd than did the other two single extractants. The oxidisable fraction was the major fraction for Cu in both biosolids-amended soils and the HOAc-soluble and reducible fractions accounted for most of the Zn. In contrast, Cd was present mainly in the reducible fraction. The results are discussed in relation to the mobility and bioavailability of the metals in polluted soils. 相似文献
272.
最近几年,市场上有一些白酒产品,利用“茅台”极高的市场信誉度和品牌价值,擅自以“茅台镇传世佳酿”、“茅台散酒”、“茅台某某酒”等相标榜,以致许多不了解情况的消费者被蒙蔽与误导,误认为是茅台酒的系列产品,与茅台酒是“一家人”。 相似文献
273.
274.
改良型Carrousel氧化沟工艺生物脱氮除磷效果研究 总被引:13,自引:0,他引:13
为了提高改良型Carrousel氧化沟工艺污水处理厂的脱氮除磷效果,结合某污水处理厂3年的运行实践,讨论了该工艺的处理效果,生物脱氮除磷原理及影响出水效果的因素。分析表明将DO控制在0.3—0.7mg/L范围内,能够使出水中的TN浓度低于20mg/L;在氧化沟中发生的同步硝化反硝化反应(SND)对总氮的去除的贡献占总系统脱氮的66%;该系统剩余污泥的含磷率为3.0%,生物细胞中平均含磷量可达细胞干重的4.2%;总磷去除率与污泥龄具有很好的线性关系,加大污泥排放量可以提高除磷效果。 相似文献
275.
乔寿锁 《城市环境与城市生态》1993,6(3):31-36
本文从环境保护的科学技术支持系统分析入手,以环境科学研究对象和内容为核心,依据系统结构的内在规定性、环境科技的横断性、综合性和环境科学活动的组织规律,提出了支持系统的结构模型和科技队伍合理配置方案,可为环保科技结构调整、分流重组和能力建设所参考. 相似文献
276.
结合西部生态环境调查积累的大量环境数据 ,围绕西部生态环境网上服务系统建设的实际应用需要 ,基于Web技术对西部生态环境信息服务系统进行了整体组织和设计 ,并对其实现技术、功能、过程等作了较详细的阐述。该系统可为公众和环境管理部门提供方便、快捷的生态环境信息。 相似文献
277.
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280.
Zijuan Lan Bin Zhang Xiaofeng Huang Qiao Zhu Jinfeng Yuan Liwu Zeng Min Hu Lingyan He 《环境科学学报(英文版)》2018,30(1):277-284
Haze in China is primarily caused by high pollution of atmospheric fine particulates (PM2.5). However, the detailed source structures of PM2.5 light extinction have not been well established, especially for the roles of various organic aerosols, which makes haze management lack specified targets. This study obtained the mass concentrations of the chemical compositions and the light extinction coefficients of fine particles in the winter in Dongguan, Guangdong Province, using high time resolution aerosol observation instruments. We combined the positive matrix factor (PMF) analysis model of organic aerosols and the multiple linear regression method to establish a quantitative relationship model between the main chemical components, in particular the different sources of organic aerosols and the extinction coefficients of fine particles with a high goodness of fit (R2 = 0.953). The results show that the contribution rates of ammonium sulphate, ammonium nitrate, biomass burning organic aerosol (BBOA), secondary organic aerosol (SOA) and black carbon (BC) were 48.1%, 20.7%, 15.0%, 10.6%, and 5.6%, respectively. It can be seen that the contribution of the secondary aerosols is much higher than that of the primary aerosols (79.4% versus 20.6%) and are a major factor in the visibility decline. BBOA is found to have a high visibility destroying potential, with a high mass extinction coefficient, and was the largest contributor during some high pollution periods. A more detailed analysis indicates that the contribution of the enhanced absorption caused by BC mixing state was approximately 37.7% of the total particle absorption and should not be neglected. 相似文献