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881.
为准确评估多环芳烃(PAHs)污染土壤对人体的健康风险,解决目前基于总量风险评估导致土壤PAHs修复目标值过严的问题,采用德国标准研究院颁布的生物可给性测试方式研究了石家庄某焦化厂土壤中苯并[b]荧蒽(BBF)、苯并[k]荧蒽(BKF)、苯并[a]芘(BAP)、茚并[1,2,3-cd]芘(IPY)和二苯并[a,h]蒽(...  相似文献   
882.
An intensive investigation was conducted to study the distribution of polycyclic aromatic hydrocarbons (PAHs), to show firstly the level of pollution in the agricultural areas and analyses specifically the status of soil polluted by these persistent pollutants in some locations of Xiamen region. Soil samples collected from Jiulong agricultural catchment have been analysed for 16 PAH compounds, using gas chromatography flame ionization detection in order to determine the level of selected PAH components and to identify the factors that may control their distribution and persistence in the area. The main PAHs found in soil samples were the low molecular weight. The total PAHs detected in soil samples ranged from 0.50 to 0.95 μg/g soil. The highest values of PAHs were significantly detected in the orange tree leaves, which range from 236.1 to 249.3 μg/g soil showing recent atmospheric inputs of these volatile pollutants. The distribution of PAHs in vegetable were monitored and indicating that the concentration were high and ranged from 8.24 to 58.87 μg/g. Other sediment samples were also collected and analysed from urban sewage (5.26 μg/g dw), aquacultural (0.52 μg/g dw) and industrial areas (from 0.62 to 2.09 μg/g dw), during this investigation. The contamination of Jiulong river estuary and Xiamen Western Sea by PAHs has been then widely justified by wastcwatcr discharges and soil runoffs from these areas. The results, therefore, provide important information on the current contamination status caused by the atmospheric transport and point to the need for urgent actions to stop the release of these hydrocarbons to the environment. The necessity of implementing systematic monitoring of PAHs is also emphasized.  相似文献   
883.
Dissipation of chlorpyrifos in pakchoi-vegetated soil in a greenhouse   总被引:2,自引:1,他引:1  
The dissipation of chlorpyrifos in pakchoi-vegetated soil was investigated in the summer and autumn in a greenhouse and field, respectively. The dissipation of chlorpyrifos in pakchoi-grown soil was comparatively described by fitting the residue data to seven models (lst-order, 1.5th-order, 2nd-order, RF lst-order, RF 1.5th-order, RF 2nd-order, and bi-exponential or two-compartment models). Statistical analysis was performed using the SPSS 11.5 statistical package. The bi-exponential model was selected as the optimal model according to the coefficient of determination r^2. The dissipation half-lives (DT50) of chlorpyrifos in pakchoi-vegetated soil at the recommended dose in the summer and autumn, calculated by the bi-exponential model, were 0.6 and 1.2 d in a greenhouse, 0.4 and 1.0 d in a field, respectively; the corresponding values at double dose were 1.2 and 2.1 d in a greenhouse, 0.5 and 1.3 d in a field, respectively. The kinetic data indicate the dissipation of chlorpyrifos in pakchoi-grown soil in a greenhouse is slower than that in a field, and dissipates slower in the autumn than in the summer.  相似文献   
884.
Chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. The key of the technology is to choose suitable additives in combination with a suitable plant. In the present study, laboratory batch experiment of metal solubilization, cress seeds germination were undertaken to investigate the metal-mobilizing capability and the phytotoxicity of organic additives, including ethylene diamine triacetic acid (EDTA), citric acid, acetic acid, oxalic acid, glutamine and monosodium glutamate waste liquid (MGWL) from food industry. Experiments in pots were carried out to study the effects of the additives on Zn and Cd phytoextraction. Furthermore, a leaching experiment with lysimeter was performed to evaluate the environmental risks of additive-induced leaching to underground water. The results showed that EDTA had a strong mobilizing ability for Zn and Cd, followed by mixed reagent (MR) and MGWL. MGWL and acetic acid at 5 mmol equivalent per liter resulted in seed germination index less than 2%. Experiments in pots verified the phytotoxicity of acetic acid and MGWL. Addition of the mixed reagent at 6--10 mmol/kg significantly increased Zn phytoextraction by Thlaspi caerulescens. The same for EDTA and the mixed reagent at 10 mmol/kg by Sedum dfredii. But only mixed reagents could significantly increase Cd phytoextraction by the studied hyperaccumulators. This suggested that the strong chelant was not always the good agent to enhance phytoextraction. S. alfredii combined with 2--10 mmol/kg soil MR was preferred for phytoremediation of Cd/Zn contaminated soils in southern China, this could result in high phytoextraction of Cd/Zn and reduce the leaching risk to underground water than EDTA assisted phytoextration.  相似文献   
885.
对长江口滨岸带无齿相手蟹体内的重金属元素分析表明:无齿相手蟹体内的Zn、Cr、Ni三种元素季节分布的总体趋势是夏季>春季>秋季。无齿相手蟹对重金属元素的累积也存在着地点间的差异。青龙港、浒浦两地的无齿相手蟹对Cu、Pb、Cr、Ni的累积量都很高,东海农场和崇明东滩的无齿相手蟹对Zn的累积量较高。对无齿相手蟹、沉积物、悬浮颗粒物中的重金属含量分析表明,无齿相手蟹对重金属Cu有一定的富集能力,适于做长江口滨岸带Cu的指示生物。  相似文献   
886.
1997~2004年中国区域经济与火灾态势的关系分析   总被引:1,自引:0,他引:1  
吴松荣 《火灾科学》2006,15(4):224-231
中国区域经济发展存在较大差异,相应的火灾,隋况也各不相同,本文通过对1997~2004这8年期间的火灾数据的分析,探讨了火灾发展态势在不同地区的特征,并分析了典型地区的火灾和社会经济发展之间的关系。结果表明,当前情况下,随着经济的发展,我国多数地区的火灾发生态势先升高后降低,最后保持平稳;经济较发达的上海地区的火灾发生率已经越过了“最高峰”而趋于平穗好转的时期,此外,同样是经济较发达北京与天津两地的火灾发生率正处于“最高峰”时期,预计在未来几年内其火灾发展将趋于好转。  相似文献   
887.
刘义祥  田宇  胡建国 《火灾科学》2006,15(4):219-223
本文模拟火灾中不同情况,制备普通白炽灯破坏的灯丝残骸,利用扫描电子显微镜(SEM)分析灯丝残骸的微观形貌,研究灯丝在不同情况下破坏的特征。发现通电状态下破坏的灯丝氧化严重,与未通电状态的灯丝具有明显的区别。即使经历了高温或火焰灼烧作用后,微观形貌特征仍具有明显的差别。根据这种微观特征可以判断火场中白炽灯的通电状态。  相似文献   
888.
践行环境(E)、社会(S)和治理(G)理念是全面推进美丽中国建设的重要举措,也是企业现代绿色治理的关键手段。本文系统分析了我国ESG政策的发展脉络,将ESG在我国的发展分为萌芽起步阶段、探索发展阶段和深化提升阶段三个阶段。通过深入剖析我国ESG体系现存的若干问题,提出加大推广和实践ESG理念的力度和深度、分批分阶段有序推进ESG信息披露标准制定、加快构建具有中国特色的ESG评级标准、强化对ESG投资的指引和规范,以及加快建设健全的ESG监管体系等政策建议。  相似文献   
889.
溶解有机质(dissolvedorganicmatter,DOM)是一类由腐殖质和非腐殖质构成的非均质混合物,广泛存在于土壤、煤炭和水体中,产生重要的生态环境效应。溶解有机质中相似组分的分离一直是有机质研究的难点。近年来,随着XAD树脂分离技术在DOM分离中的广泛应用,腐殖质和非腐殖质的分离取得了很大进展,文章对这些方法进行了详细的综述,并做了进一步的展望。  相似文献   
890.
安徽省升金湖湿地土壤有机碳储存及分布   总被引:7,自引:0,他引:7  
文章研究了安徽省升金湖湿地土壤有机碳储存和分布特征及其与土壤氮素的关系。结果表明,供试湿地土壤全土1m深有机碳密度达10.82±1.90kg.m-2,表层土壤(0—30cm)有机碳密度为5.19±0.68kg.m-2,高于报道的人工湿地——水稻土的碳密度;有机碳(SOC)含量分布随土壤深度(H)的递降符合幂函数方程,湿地土壤有机碳的表层积累强度和积累深度高于稻田;湿地土壤氮素是土壤固碳的有利因子,其氮素对土壤有机碳积累的效应高于水稻土;因湖泊沉积受河流动力学、土壤水分和植物生长条件的影响,湿地土壤有机碳含量存在显著的水平空间变异性。看来,长江中下游淡水湿地在陆地生态系统碳氮储存上具有重要意义。  相似文献   
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