Caution needed in pretreatment of sediments for refining phosphorus-31 nuclear magnetic resonance analysis: results from a comprehensive assessment of pretreatment with ethylenediaminetetraacetic acid

Pretreatment with chemicals such as ethylenediaminetetraacetic acid (EDTA) is often used to improve the analysis of sediment P with solution P-31 nuclear magnetic resonance spectroscopy (35P-NMR), but there is a lack of a comprehensive assessment of the methodology. In this study, the effects of EDTA pretreatment on sediment P extracted using a mixture of 0.25 mol L(-1) NaOH and 50 mmol L(-1) EDTA (NaOH-EDTA) were examined with 45 different sediments. The results showed that EDTA pre-extraction decreased the amount of P extracted by NaOH-EDTA when the concentration ratio of sediment Ca to the sum of sediment Fe and Al [Ca/(Fe+Al), on a wt/vol basis] was lower than 0.4. An increase in total extracted P, coupled with substantial increases in total extracted paramagnetic ions such as Fe and Mn, was observed for another group of sediments with Ca/(Fe+Al) > 0.5, possibly due to the matrix effect. Analysis of 16 representative sediments with 31P-NMR showed that orthophosphate diesters were substantially removed by EDTA pre-extraction for sediments with Ca/ (Fe+Al) between 0.4 and 0.7, reflecting a high risk posed by this pretreatment. Phosphorus diversity and concentration of individual P compounds were markedly improved for sediments with Ca/(Fe+Al) > 0.7, suggesting that EDTA pretreatment was particularly useful for 31P-NMR analysis of calcareous sediments. The present study showed that sediment properties played an important role in determining pretreatment effects. Caution is advised when applying pretreatment methods to different sediments.     

污泥循环再利用技术在油田废水处理中的应用

通过对中原油田含油污泥的再利用进行实验研究,得到结果:污泥的平均固含量为75.18%,含水量为24.82%,污泥含油量5.4%;污泥中碳酸钙含量62.15%,碳酸镁含量15.295%,氯化钠含量2.696%;在废液与污泥的掺入比例小于1:4的条件下,废液得到有效净化。污泥循环再利用技术的实施,降低了污泥产生量。     

F-T合成技术生产替代燃料对环境的影响及对策

主要介绍了F-T合成柴油的特性,阐述了其作为清洁能源的优越性;利用生命周期清单分析方法,比较了以煤、生物质及天然气为原料采用F-T合成技术生产替代能源的工艺路线前提下,在提取生产、转化精炼、运输分配、最终用途燃烧、全部燃料链各阶段温室气体排放情况,提出了温室气体的减排对策。     

Bioaccumulation and physiological effects of tetrabromobisphenol A in coontail Ceratophyllum demersum L

Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants. In the present study, the accumulation of TBBPA and its consequent biological responses were examined in coontail (Ceratophyllum demersum L.) over 14 days' exposure. Most of the TBBPA was accumulated after 4d exposure and TBBPA concentration in plant increased with increasing TBBPA concentration in growth solution (R(2)=0.99). By using electron paramagnetic resonance (EPR), we found that the TBBPA exposure significantly increased total free radicals generation in the plants. A good positive relationship (R(2)=0.99) was found between the free radicals formation and accumulation level of TBBPA in plant. Lipid peroxidation was enhanced and chlorophyll content showed declined after TBBPA exposure. The activities of superoxide dismutase (SOD), peroxidase (POD), and the contents of glutathione were also detected. The results suggest that TBBPA accumulation in C. demersum induces oxidative stress and the level of tolerance depends on the antioxidative capacity of the plants.     

多普勒雷达回波在一次大暴雨中的应用分析

利用多部新一代天气雷达资料结合常规探空资料和逐小时的自动站资料,对2007年7月18日发生在河北省东部平原(以下简称冀东平原)的一次区域性暴雨过程进行分析。结果发现:低层中α尺度切变线的南压、东移及"人"字形辐合线是本次降水过程的主要影响系统;降水发生前西南暖湿气流和冀东平原近地层偏东风是"人"字形辐合线形成的直接原因;在不稳定层结存续条件下,急流方向上上游雷达站中尺度低空急流的脉动对下游台站的短时暴雨预报具有一定时效的指示意义。     

远离肺结核

<正>2010年3月24日是第15个"世界防治结核病日",其主题是"遏制结核,健康和谐",旨在呼吁全社会共同关注结核病疫情现状和防控形势,采取行动,遏制结核病流行,使更多的人免受结核病的危害,保障广大群众的身体健康。     

Seasonal Variation of Inorganic Nutrient Uptake by Heterotrophic Bacterioplankton in Jiaozhou Bay,North China

The distribution patterns and factors affecting uptake rates and turnover times of dissolved inorganic nutrients by heterotrophic bacterioplankton (HB) in Jiaozhou Bay were studied based on in situ surveys and laboratory culturing. The uptake rates of dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) by HB are limited by the temperature of the water and the concentration of dissolved organic carbon. The turnover times of DIP and DIN by HB are regulated by the concentrations of the nutrients and the numbers of HB, which show significant spatiotemporal variability in Jiaozhou Bay. HB may aggravate the P-limitation of phytoplankton by competing for phosphorus in summer in Jiaozhou Bay. HB play an important role in the biogeochemical cycling of nutrients and may increase the N:P ratio and the accumulation of DIN, thereby accelerating the imbalance of the N:P ratio in Jiaozhou Bay.     

世界废弃印刷电路板的机械处理技术现状

电子废弃物中废印刷电路板的处置 ,一直是相当复杂的问题。根据废电路板中各种组分的结合方式 ,采用机械方法进行材料的分离 ,是经济适用并与环境相协调的处理手段。本文介绍了废电路板再利用技术中采用的各种机械设备 ,并总结了国外机械处置方法的实践进展。     

生物-物化法治理稀黑液工艺

提出了以从自然界分离得来的组合菌CG、WD,结合物化法治理稀黑液的工艺方法.结果表明,1.5°Be′左右的稀黑液经本工艺处理,硫化物、挥发酚去除率均达99%以上,色度、CODcr和BOD