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971.
The accumulation of heavy metals (Cd, Cr, Cu, Pb and Zn) and magnetic minerals in soils along an urban-rural gradient in the rapidly growing Hangzhou City, Eastern China, was measured. The analytical results indicated that heavy metal concentrations, magnetic susceptibility (chilf) and saturation isothermal remnant magnetization (SIRM) in soils decreased with increasing distance from the urban center. The significant relationships existed between heavy metal concentrations, chilf and SIRM and distance from the urban center. The soils in the urban areas were enriched with Cd, Cu, Pb and Zn. Elevated concentrations of heavy metals (especially Cd and Zn) in urban areas indicated the evidence for the accumulation of heavy metal contaminants from anthropogenic activities. Enhanced heavy metal concentrations and magnetic susceptibility were located in the uppermost soil horizons (0-10 cm), decreasing downwards to background values. The significant positive correlations between the Tomlinson Pollution Load Index (PLI) and magnetic susceptibility and SIRM were observed in polluted soil samples. Strong positive correlation indicated that magnetic screening/monitoring provided a fast and non-destructive tool, which can be effectively used as a proxy to detect environmental pollution in rapidly growing urbanization regions affected by anthropogenic activities. 相似文献
972.
Novel hyperspectral reflectance models for estimating black-soil organic matter in Northeast China 总被引:4,自引:0,他引:4
This paper presents a novel method for estimating black-soil organic matter (SOM) in the black-soil zone of northeast China from hyperspectral reflectance models. Traditional black-soil property measurements are relatively slow, but the pressures of agricultural production and environmental protection require a quick method to collect black-soil organic matter content. SOM estimation using soil hyperspectral reflectance models can meet this requirement, based on the spectral characteristics of black-soil in Northeast China. On the basis of the spectral reflectance and its derivatives, hyperspectral models can be built using correlation analysis and multivariable statistical methods. The concepts of curvature and ratio indices are also applied to compare and test the stability and accuracy of data modeling. The results show that the response of black-soil spectral reflectance from 400-1,100 nm to organic matter content is more marked than that from 1,100-2,500 nm. Specifically, the main response range of black-soil organic matter is between 620-810 nm, with a maximal spectral response at 710 nm. By comparing different models, we found that the normalized first derivate model is optimal for estimating SOM content, with a determination coefficient of 0.93 and root mean squared errors (RMSE) of 0.18%. 相似文献
973.
Qian Zhang Yang Zhao Sufang Fan Aijuan Bai Xuesheng Li Canping Pan 《Environmental monitoring and assessment》2013,185(12):9743-9749
The dissipation and residues of bispyribac-sodium in rice cropping system were studied. Bispyribac-sodium residues were extracted by a simple analytical method based on QuEChERs and detected by LC-MS/MS. The limit of detection for bispyribac-sodium of this method was 0.375?×?10?3 ng. The limit of quantification (LOQ) was 5.0 μg/kg for rice plant samples, 2.0 μg/kg for rice hull, 0.2 μg/kg for water, and 0.1 μg/kg for soil and husked rice samples. The average recoveries of bispyribac-sodium ranged from 74.7 to 108 %, with relative standard deviations less than 13 %. The half-lives of bispyribac-sodium in rice plant, water, and soil were in the range of 1.4–5.6 days. More than 90 % of bispyribac-sodium residue dissipated within 5 days. The final residues of bispyribac-sodium in rice were all below LOQ at harvest time. 相似文献
974.
Yang Bai Pingya Luo Pingquan Wang Wei Bai Chengdong Xiong Congming Tang 《Journal of Polymers and the Environment》2013,21(4):1016-1025
The poly(para-dioxanone) (PPDO)/poly poly (dl-lactide) (PDLLA) blends containing various contents of compatibilizer (0, 1, 3, 5, 10 %) were prepared by solution co-precipitation, which were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) to form 10 % wt/vol solutions. Then in vitro hydrolytic degradation of PPDO/PDLLA blends containing poly (dl-lactide-co-para-dioxanone) (PLADO) as the compatibilizer was studied by the changes of weight loss, water absorption, thermal properties, surface morphology and mechanical properties of samples in phosphate buffered saline (pH 7.44) at 37 °C for 8 weeks. During the degradation, the weight loss and water absorption increased significantly for all blends, whereas hydrolysis rate of blends varied with the blend composition. The samples’ glass transition temperature decreased notably, while the degrees of crystallinity increased. Compared with uncompatibilized PPDO/PDLLA blends, PPDO/PDLLA blends with compatibilizer exhibited higher hydrolysis rate. The results suggested that the compatibilizer (PLADO) accelerated the hydrolysis rate of PPDO/PDLLA blends during the degradation. 相似文献
975.
976.
固定化膜生物反应器处理含抗生素污水 总被引:2,自引:0,他引:2
采用细菌固定化技术包埋活性污泥浓缩液,并利用A/O膜生物反应器处理含抗生素生活污水,考察了膜生物反应器在抗生素存在条件下降解有机物及氮素的性能,并对土霉素为代表的抗生素的去除效果进行分析。结果表明,人工模拟抗生素污水的COD、TOC、NH4+-N、TN及土霉素浓度分别为325~413、101.35~206.10、15.51~24.54、15.00~25.30和0.17~0.47 mg/L,水力停留时间为6、12和24 h的条件下,系统的出水平均COD、TOC、NH4+-N和TN分别维持在50、20、1和3 mg/L以下,对土霉素的平均去除率分别达到64%、72%和75%;研究还发现固定化膜生物反应器对进水中氨氮的波动具有良好的抗冲击负荷能力且可以延缓膜污染,正确调整水处理工艺的运行工序可以在提高水处理效率的同时有效降低水环境中的抗生素药物含量。 相似文献
977.
978.
以从我国最大的石油污水灌区之一——沈抚灌区污染土壤分离到的以芘为惟一碳源、能源生长的高效降解菌株ZQ5为实验材料,通过对菌株ZQ5培养条件的优化,以及采用摇瓶振荡培养方法测定菌株ZQ5对不同浓度芘的降解率,表明:菌株ZQ5在30℃振荡培养16 d后对150 mg/L芘的降解率为90.31%。通过模拟稻田施用N、P和K肥等的土壤环境,探索了无机营养元素对降解菌ZQ5降解能力的影响,发现土壤中混合加入N、P和K无机营养元素的降解率能达到82%以上,比单加某种营养元素对降解菌ZQ5的降解效果好。本研究结果可以指导稻田PAHs的原位生物修复。 相似文献
979.
以桂林市第四污水处理厂氧化沟活性污泥为对象,研究在具有厌氧-缺氧-好氧环境的污水处理构筑物中富集存在的反硝化聚磷菌聚磷能力的持久性问题。结果表明,在此环境中富集的反硝化聚磷菌在经过3个周期的厌氧-缺氧条件下运行,最大释磷率由0.90 mg P/(g VSS.h)下降为0.07 mg P/(g VSS.h),反硝化聚磷率由0.17 mg P/(g VSS.h)下降为0.04 mg P/(g VSS.h)。比较而言,在厌氧-缺氧-好氧环境下最大释磷率及聚磷率降幅较小,释磷率由0.59 mg P/(gVSS.h)下降为0.37 mg P/(g VSS.h),反硝化聚磷率由0.17 mg P/(g VSS.h)下降为0.10 mg P/(g VSS.h),厌氧-缺氧-好氧运行条件比单纯的厌氧-缺氧运行条件更有利于维持反硝化聚磷菌的聚磷性能。 相似文献
980.
好氧堆肥反应器对人粪便堆肥中温降解的中试研究 总被引:1,自引:0,他引:1
控制温度为(35±2)℃,以新鲜锯末为空白载体,在控制含水率为55%~60%和强制通风的好氧条件下,进行为期15 d的实验,进行了人粪便好氧堆肥的中试研究,重点分析了在堆肥过程中有机物的降解、氮素的迁移转化规律及生物量的变化。结果表明,粪便中有机物含量在前2天稍微上升,然后迅速下降,最终去除率为71.82%;随着NH3-N释放量的增加,堆料中Ntot含量从第4天开始减少,最终损失 22.61%,其中Norg损失占74.35%,NH3-N占23.52%;所损失的氮素有91.66%以氨氮的形式释放。粪便中的有机物和氮的含量能在8~10 d后达到稳定,且堆体无臭味;粪便中溶解性有机物为微生物的生长提供营养物质,因此生物量变化的过程与有机物降解的有着紧密的联系;病原菌在堆肥过程中得到有效去除,表明该反应器堆肥的无害化。 相似文献