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光度法测定挥发酚的实验研究 总被引:1,自引:0,他引:1
文章对挥发酚测定过程中可能影响检测结果的因素进行研究。探讨实验用无酚水的制备与保存,无酚水的替代用水,蒸馏预处理的技术要求,标准曲线制作的方法改进,加药比色中常见的问题。得出:在挥发酚的测定实验中,要使用无酚水或等质量的实验用水进行试剂配制和样品测定,要进行蒸馏预处理等,提高了测定数据的准确性。 相似文献
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Chen YH Wang MK Wang G Chen MH Luo D Ding FH Li R 《Journal of environmental quality》2011,40(6):1903-1910
Sewage sludge (SS) applied to sloping fields at rates that exceed annual forest nutrient requirements can be a source of phosphorus (P) in runoff. This study investigates the effects of different slopes (18, 27, 36, and 45%) on P in runoff from plots amended with SS (120 Mg ha). Lateritic soil (pH 5.2) was exposed to five simulated rainfalls (90 mm h) on outdoor plots. When sludge was broadcast and mixed with surface soils, the concentrations and loss in runoff of total P in the mixed sample (MTP), total P in the settled sample (STP), total particulate P (TPP), total suspended P (TSP), and total dissolved P (TDP) were highest at 1 or 18 d after application. Initially, pollution risks to surface waters generally increased to different degrees with steeper slopes, and then diminished gradually with dwindling differences between the slopes. The runoff losses coefficient of MTP increased in the order 36 > 45 > 27 > 18%. The initial event (1 and 18 d) accounted for 67.0 to 83.6% of total runoff P losses. Particulate fraction were dominant carriers for P losses, while with the lower slopes there was higher content of P per unit particulate fraction in runoff. Phosphorus losses were greatly affected by the interaction of sludge-soil-runoff and the modification of soil properties induced by sludge amendment. It is recommended to choose lower slopes (<27%) to reduce risk of P losses. Thus, the risk of application sludge to sloping fields in acid soils should be studied further in the field under a wider diversity of conditions. 相似文献
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Guang Hong Wu Shan Shan Cao Shui Rong Chen Fang Ting Cao 《Environmental monitoring and assessment》2011,173(1-4):917-928
The concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in superficial sediment samples collected from three representative sites (Yuqiao Reservoir, Haihe River, and Haihe River Estuary) in Tianjin, North China, were analyzed using various single extraction and sequential extraction procedures to determine their remobilization, extractability, and distribution patterns. Sediments from the Haihe River had higher metal concentrations and geo-accumulation indices, especially for Cd and Zn, than sediments from the other two sites, suggesting that the Haihe River has been heavily influenced by anthropogenic activities. In addition, over 31% and 28.2% of the total Cd in the Haihe River and the Yuqiao Reservoir, respectively, and 18.2% of the total Zn in the Haihe River were found to be associated with the exchangeable form, indicating the significant remobilization of Cd and Zn when compared with Cr and Ni. However, over 98% of the Ni and 78% of the Cr were most closely associated with the residue and oxidizable fractions, which resulted in their becoming environmentally immobile. Based on the Environmental Protection Agency method 3050B, Cd and Zn had the greatest extraction efficiency when a single extraction procedure using 0.5-mol L???1 HCl, 0.43-mol L???1 HAcO, and 0.05-mol L???1 ethylene-diamine-tetra-acetic acid was conducted, with extraction yields of up to 72%, 68%, and 56% for Cd and 50%, 49%, and 29% for Zn, respectively, being obtained for the Haihe River sediments. This was followed by the yields of Cu and Pb and, finally, those of unpolluted metals such as Cr and Ni. HCl and acetic acid extraction provided equivalent information for predicting Cd and Zn mobility in the sediments studied and produced suitable results for quick screening. 相似文献
667.
A seasonal field campaign by passive sampling was conducted from February 2008 to February 2009, aiming to measure air concentrations of organochlorine pesticides (OCPs) in the urban and suburban areas in Dalian. At the urban site, similar annual average concentrations of α-endosulfan and α-HCH were found, both being approximately 4 times as high as those of p,p'-DDT and p,p'-DDE, while at the suburban site, the annual average concentration of α-endosulfan was 2.9 times as high as the average concentrations of α-HCH, p,p'-DDT and p,p'-DDE; concentrations of α-endosulfan, α-HCH and p,p'-DDE achieved annual peaks in summer. Back trajectory analysis revealed that the air concentration of α-endosulfan increased with the input of air masses from the land whereas decreasing air concentration of α-endosulfan at the urban site was associated with air masses from the sea. Pesticides used in local agriculture were identified to be major sources of α-endosulfan at both the urban and suburban sites, though long-range atmospheric transport from other sources might also contribute to atmospheric levels of this chemical over this coastal city. α-endosulfan, α-HCH, p,p'-DDT and p,p'-DDE in the air in Dalian might result from the atmospheric transport of the air masses from northeast area, Shandong peninsula and Korean peninsula. Emission due to "aged" DDT and HCH in contaminated local soils as well as atmospheric long-range transport were likely to be major sources of α-HCH, p,p'-DDT and p,p'-DDE at the suburban site. In addition, a fresh input of α-HCH and p,p'-DDT in the atmosphere could not be excluded in the urban area. 相似文献
668.
微丝菌(Microthrix parvicella)是世界范围内诱发活性污泥膨胀现象的主要丝状菌之一,它在活性污泥中准确的原位定量解析对污泥膨胀现象及控制策略研究具有非常重要的意义.由于微丝菌自身的特殊生理生化性质(如表面高疏水性及较厚细胞壁)易导致常规荧光原位杂交(FISH)过程中定量结果偏低.本研究针对FISH过程中存在的探针渗透率低、荧光信号偏弱等现象,从活性污泥样品前处理、杂交过程条件等方面对Microthrix parvicella的FISH定量过程进行了优化.结果表明,在前处理使用溶菌酶(浓度为36 000 U·m L~(-1)),探针浓度为4.5 ng·μL~(-1),杂交时间延长至4 h的条件下,Microthrix parvicella的FISH定量结果可从1.12%提高至96.70%,并与定量PCR(q-PCR)结果和EikelboomJenkins法(镜检观察)定量结果更为趋近一致. 相似文献
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为了对生态环境质量进行综合评价,运用环境景观格局综合评价方法,对西成客运专线西安至江油段铁路段划分出9个不同的生态环境类型。西城客运专线铁路的修建对沿线的耕地和林地影响较大,对水地和草地的影响较小,是西成客运专线施工和后期生态恢复中主要评价和研究的内容。环境景观综合评价表明,横贯中国南北自然地理分界线秦岭的西城客运专线的修建对沿线景观环境影响程度较轻、铁路与沿线景观较为协调,表明西城客运专线设计比较合理。同时,评价的结果也说明,采取恰当的工程措施可以最大限度地减小对自然生态环境的破坏。 相似文献