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酒石酸淋洗过程中土壤重金属解吸动力学特征 总被引:1,自引:0,他引:1
采用批处理淋洗的方法,研究了酒石酸淋洗修复张士污灌区土壤过程中镉、铅、铜、锌4种重金属离子解吸动力学特征。结果表明,酒石酸在12h条件下,达到对污染土壤中镉离子的最大去除率,铅、铜、锌3种重金属离子达到最大去除率则需要24h。4种重金属离子的解吸动力学过程可以用Elovich方程很好的描述,说明酒石酸去除重金属离子的过程是一种非均相扩散过程。此外,解吸速率曲线显示,反应初期相同时刻上酒石酸对铅离子的解吸速率最快,其次是铜和锌,最后是镉离子;反应后期同一时刻上铜和锌的解吸速率大于铅和镉。 相似文献
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Differences in nitrous oxide fluxes from red soil under different land uses in mid-subtropical China 总被引:1,自引:0,他引:1
Shan LinJaved Iqbal Ronggui Hu Leilei RuanJinshui Wu Jinsong ZhaoPengju Wang 《Agriculture, ecosystems & environment》2012,146(1):168-178
Red soil may play an important role in nitrous oxide (N2O) emissions due to its recent land use change pattern. To predict the land use change effect on N2O emissions, we examined the relationship between soil N2O flux and environmental determinants in four different types of land uses in subtropical red soil. During two years of study (January 2005-January 2007), biweekly N2O fluxes were measured from 09:00 to 11:00 a.m. using static closed chamber method. Objectives were to estimate the seasonal and annual N2O flux differences from land use change and, reveal the controlling factors of soil N2O emission by studying the relationship of dissolved organic carbon (DOC), microbial biomass carbon (MBC), water filled pore space (WFPS) and soil temperature with soil N2O flux. Nitrous oxide fluxes were significantly higher in hot-humid season than in the cool-dry season. Significant differences in soil N2O fluxes were observed among four land uses; 2.9, 1.9 and 1.7 times increased N2O emissions were observed after conventional land use conversion from woodland to paddy, orchard and upland, respectively. The mean annual budgets of N2O emission were 0.71-2.21 kg N2O-N ha−1 year−1 from four land use types. The differences were partly attributed to increased fertilizer use in agriculture land uses. In all land uses, N2O fluxes were positively related to soil temperature and DOC accounting for 22-48% and 30-46% of the seasonal N2O flux variability, respectively. Nitrous oxide fluxes did significantly correlate with WFPS in orchard and upland only. Nitrous oxide fluxes responded positively to MBC in all land use types except orchard which had the lowest WFPS. We conclude that (1) land use conversion from woodland to agriculture land uses leads to increased soil N2O fluxes, partly due increased fertilizer use, and (2) irrespective of land use, soil N2O fluxes are under environmental controls, the main variables being soil temperature and DOC, both of which control the supply of nitrification and denitrification substrates. 相似文献
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Persistence and mobility of 2,4-D in unsaturated soil zone under winter wheat crop in sub-tropical region of India 总被引:3,自引:0,他引:3
Manika GuptaN.K. Garg Himanshu JoshiM.P. Sharma 《Agriculture, ecosystems & environment》2012,146(1):60-72
The present study was undertaken to determine the persistence and mobility of 2,4-dichlorophenoxy acetic acid (2,4-D) in unsaturated soil zone under real field conditions for the wheat crop in Roorkee, India. Three experimental plots were chosen in the agricultural field itself to represent the real field conditions in the study area and the potential movement and persistence of herbicide 2,4-D was investigated under three different irrigation treatments. The presence of herbicide along with soil water content was determined in soil at different depths at a temporal scale. The movement of the herbicide was also simulated numerically by solving the coupled soil water content movement and mass transport equations using HYDRUS-1D. The measured soil water content trends and the 2,4-D concentration profiles showed a good agreement with the numerically simulated results. The maximum effect of the herbicide was primarily retained up to 15 cm of the soil profile. The current existing dosage of 0.5 kg ha−1 of pesticide was found to be safe to avoid soil contamination as no residue of 2,4-D was traced at the end of the wheat crop season in any of the plots. Higher concentrations of 2,4-D were also simulated numerically and the simulated results showed that the safe dosage of pesticide application would depend on irrigation treatments. 相似文献
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夏季广州城区细颗粒物PM_(2.5)和PM_(1.0)中水溶性无机离子特征 总被引:24,自引:13,他引:11
于2008年7月1~31日在广州城区每天采集PM2.5和PM1.0样品.利用离子色谱分析了样品中Na+、NH4+、K+、Mg2+、Ca2+、F-、Cl-、NO3-和SO24-等9种离子组分质量浓度,并同步收集气象因子、大气散射系数、大气能见度以及SO2、NO2、O3气体污染物质量浓度等数据.结果表明,PM2.5和PM1.0中水溶性无机离子总浓度分别为(25.5±10.9)μg·m-3和(22.7±10.5)μg·m-3,分别占PM2.5和PM1.0质量浓度的(47.9±4.3)%和(49.3±4.3)%.SO42-占PM2.5和PM1.0中质量浓度百分比最高,分别为(25.8±4.0)%和(27.5±4.5)%.较高的温度和O3浓度有利于SO24-的生成,较高相对湿度有利于NO3-的生成.PM2.5和PM1.0中亲水性较强的SO42-、NH4+和NO3-对散射系数和能见度影响较大. 相似文献
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Guocheng Hu Xiaojun Luo Fengchao Li Jiayin Dai Jianyang Guo Shejun Chen Cao Hong Bixian Mai Muqi Xu 《环境科学学报(英文版)》2010,22(2):176-183
Organochlorine pesticides(OCPs),polychlorinated biphenyls(PCBs),and polycyclic aromatic hydrocarbons(PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river(Fuhe River) in North China.Total concentrations of OCPs,PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng/g,2.3 to 197.8 ng/g,and 101.3 to 6360.5 ng/g,respectively.The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake.For hexachlorocyclohexane(HCHs) and dichlorodiphenytrichloroethanes(DDTs),α-HCH and p,p-DDT were predominant isomers;while for PCBs,PCB 28/31,PCB 40/103,PCB 60,PCB 101,and PCB 118 were predominant congeners.Possible sources derived from historical usage for OCPs and incomplete combustion fuel,wood,and coal and exhaustion of boats or cars for PAHs.Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact. 相似文献
29.
选取典型滇池湖滨蔬菜种植区——昆明福保村为研究对象,进行土壤污染物生态风险分析,结合污染物空间分布规律研究,解析污染物来源。结果表明,土壤多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)、有机氯(Organic Chlorine Pesticides,OCPs)、酞酸酯(Phthalic Acid Esters,PAEs)类污染物残留水平较低,但重金属含量相对较高,存在一定生态风险;区域内的印刷厂、造纸厂、彩印厂是土壤污染物的主要来源;滇池湖滨蔬菜种植区土壤环境质量尚为清洁,能够保障蔬菜产品品质安全。 相似文献
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特定岸坡生态系统去除水源中微量有机物实验研究 总被引:1,自引:0,他引:1
水源地长期污染严重,微量有机物检出率增加,水质安全性下降,以及岸坡传统硬质化护砌导致生态恶化,为此提出以新型环保材料生态混凝土构建特定岸坡生态系统改善水源水质的研究方法.中试实验结果表明,停留时间为6 d时,水中阿特拉津、邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯的去除率分别为70.5%、57.7%、72.4%、62.4%和45.1%,水样有机物图谱峰数与黄浦江原水相比减少23个,峰总面积降低36.8%;相同条件下对照水库(岸坡硬质护砌),5种微量有机物的去除率仅为40.2%、42.9%、54.8%、52.0%和16.2%.以生态混凝土为载体构建的水源地特定岸坡生态系统在微生物和绿色植物等多因素协同作用下,使水中微量有机物去除效果明显,对改善水源水质和生态修复具有积极意义. 相似文献