RPB-O3/H2O2法处理硝基苯模拟废水

在超重力场中,研究了硝基苯模拟废水的臭氧/双氧水(O3/H2O2)法处理效果,考察了超重力因子β、H2O2浓度、初始p H、液体流量及处理时间等因素对硝基苯去除率的影响。结果表明,硝基苯去除率随超重力因子β和处理时间的增加而增大,而随H2O2浓度、初始p H和液体流量的增加呈先增大后降低的趋势。当硝基苯初始浓度300 mg/L,工艺条件β=80、p H=10.0、臭氧质量浓度约为40 mg/L、H2O2浓度为4.9 mmol/L、液体流量为120 L/h时,循环处理35 min硝基苯去除率可达96.7%。处理时间60 min后,废水中硝基苯含量1.4 mg/L,COD为39 mg/L,达国家一级排放标准(GB 8978-1996)。在此条件下,硝基苯的降解过程符合准一级反应动力学。     

H and O isotopic differences in typhon and urban-induced heavy rain in Tokyo

Stable isotope ratios of hydrogen and oxygen of water are useful tracers of the hydrological cycle. For example, isotopes monitor the evapotranspiration in vegetated areas, local snow ice processes and stream water flow processes. δ¹⁸O and δD in rainwater reflect the processes of evaporation, condensation and precipitation. Heavy rains thus modify the stable isotope ratio of ground water, stream water and transpiration water vapor. However, the controlling factors of δ¹⁸O and δD are not clear. Here we analyzed the inorganic ion concentration and stable isotope ratio in 38 normal rainwater and 15 heavy rainwater samples were collected in Shinjuku, Tokyo, Japan, during four years from October 2012 to December 2015. Results show a decrease in δ¹⁸O and δD values with the total rainfall amount, thus highlighting the amount effect. δ¹⁸O and δD volume-weighted mean values in typhoon heavy rain were higher than the values estimated from amount effect, whereas δ¹⁸O and δD volume-weighted mean values in urban-induced heavy rain were lower. Typhoon heavy rain has high Na⁺ ratio and stable isotope ratios, while urban-induced heavy rain has low Na⁺ ratio and stable isotope ratio.     

Toxicity models of metal mixtures established on the basis of “additivity” and “interactions”

Observed effects of metal mixtures on animals and plants often differ from the estimates, which are commonly calculated by adding up the biological responses of individual metals. This difference from additivity is commonly referred to as being a consequence of specific interactions between metals. The science of how to quantify metal interactions and whether to include them in risk assessment models is in its infancy. This review summarizes the existing predictive tools for evaluating the combined toxicity of metals present in mixtures and indicates the advantages and disadvantages of each method. We intend to provide eco-toxicologists with background information on how to make good use of the tools and how to advance the methods for assessing toxicity of metal mixtures. It is concluded that statistically significant deviations from additivity are not necessarily biologically relevant. Incorporation of interactions between metals in a model does not on forehand mean that the model is more accurate than a model developed based on additivity only. It is recommended to first use a relatively simple method for effect prediction of uninvestigated metal mixtures. To improve the reliability of toxicity modeling for metal mixtures, further efforts should focus on balancing the relationship between the significance of statistics and the biological meaning, and unraveling the toxicity mechanisms of metals and their mixtures.

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<Emphasis Type="Italic">Synechococcus</Emphasis> production and grazing loss rates in nearshore tropical waters

Temporal variation of Synechococcus, its production (μ) and grazing loss (g) rates were studied for 2 years at nearshore stations, i.e. Port Dickson and Port Klang along the Straits of Malacca. Synechococcus abundance at Port Dickson (0.3–2.3 × 10⁵ cell ml^?1) was always higher than at Port Klang (0.3–7.1 × 10⁴ cell ml^?1) (p < 0.001). μ ranged up to 0.98 day^?1 (0.51 ± 0.29 day^?1), while g ranged from 0.02 to 0.31 day^?1 (0.15 ± 0.07 day^?1) at Port Klang. At Port Dickson, μ and g averaged 0.47 ± 0.13 day^?1 (0.29–0.82 day^?1) and 0.31 ± 0.14 day^?1 (0.13–0.63 day^?1), respectively. Synechococcus abundance did not correlate with temperature (p > 0.25), but nutrient and light availability were important factors for their distribution. The relationship was modelled as log Synechococcus = 0.37Secchi ? 0.01DIN + 4.52 where light availability (as Secchi disc depth) was a more important determinant. From a two-factorial experiment, nutrients were not significant for Synechococcus growth as in situ nutrient concentrations exceeded the threshold for saturated growth. However, light availability was important and elevated Synechococcus growth rates especially at Port Dickson (F = 5.94, p < 0.05). As for grazing loss rates, they were independent of either nutrients or light intensity (p > 0.30). In nearshore tropical waters, an estimated 69 % of Synechococcus production could be grazed.     

基于主成分和粒子群优化支持向量机的水质评价模型

水质的评价是治理水污染必不可少的工作。为了准确、快速地对水质进行评价,利用主成分分析法从水质监测常见的多个物化指标提取出主成分,然后将主成分作为支持向量分类机的输入,利用历史数据进行水质评价训练并用粒子群算法优化参数,构造出水质评价模型,将从物化指标中得出的主成分代入此模型即可得到水质类别。最后,选取水质监测点实测数据进行试验,结果表明,模型的水质评价结果准确且稳定。     

介质阻挡放电协同Ag/Al_2O_3对NO_x脱除的影响

为有效去除发电厂烟气中产生的NOx,利用介质阻挡放电(DBD)产生低温等离子体并结合催化剂Ag/Al2O3进行烟气脱硝实验,研究了在加入乙烯的条件下,平均负载量、催化温度和装置的布置方式对NOx脱除的影响。结果表明,随着负载的增多,NO脱除率呈现先增大后减小的趋势,5种负载量中最佳为1.76%;随着催化温度的升高,NO脱除率同样呈现先增大后减小的趋势,最佳的催化温度为150℃左右;3种不同布置方式对NO和NOx脱除有明显差别,单独催化剂在NO和NOx的脱除率都比较低;单独介质阻挡放电NO脱除率很高,但是NOx很却很低;而两者结合在NO和NOx都达到了很好的效果。     

不同暴露途径下有机污染物对大鼠急性毒性的相关性研究

不同暴露途径下有机物在生物体内的吸收分布不同,导致毒性效应亦不同,研究化学品在不同暴露途径下对生物体的毒性,对化学品的安全性评价有实际意义。本文通过研究静脉注射、腹腔注射、肌肉注射与经口灌胃4种暴露途径下527个有机物对大鼠的急性毒性数据相关性,比较了不同暴露途径下大鼠对有机污染物的敏感度顺序,结果为:静脉注射>腹腔注射>肌肉注射>经口灌胃途径,静脉注射途径下log1/LD50与其他几种注射途径下的log1/LD50有较显著的相关性,但是与灌胃途径下毒性值之间的相关性较差,相关系数r的范围为0.82~0.97。通过逐项分析研究不同暴露途径下化合物对大鼠的急性毒性与生物利用度、吸收速率、消除速率以及代谢过程的关系,结果表明,导致这种差异的原因主要是有机污染物在大鼠体内的吸附动力学过程不同所致。     

Is it only the regulatory status? Broadening the debate on cisgenic plants

In current debates on emerging technologies for plant breeding in Europe, much attention has been given to the regulatory status of these techniques and their public acceptance. At present, both genetically modified plants with cisgenic approaches—using genes from crossable species—as well as transgenic approaches—using genes from different species—fall under GMO regulation in the EU and both are mandatorily labelled as GMOs. Researchers involved in the early development of cisgenic GM plants convey the message that the potential use and acceptance of cisgenic approaches will be seriously hindered if GMO regulations are not adjusted. Although the similar treatment and labelling of transgenic and cisgenic plants may be a legitimate concern for the marketability of a cisgenic GM plant, there are concerns around their commercialization that reach beyond the current focus on (de)regulation. In this paper, we will use the development of the cisgenic GM potato that aims to overcome ‘late blight’—the most devastating potato disease worldwide—as a case to argue that it is important to recognize, reflect and respond to broader concerns than the dominant focus on the regulatory ‘burden’ and consumer acceptance. Based on insights we gained from discussing this case with diverse stakeholders within the agricultural sector and potato production in Norway during a series of workshops, we elaborate on additional issues such as the (technical) solution offered; different understandings of the late blight problem; the durability of the potato plant resistance; and patenting and ownership. Hence, this paper contributes to empirical knowledge on stakeholder perspectives on emerging plant breeding technologies, underscoring the importance to broaden the scope of the debate on the opportunities and challenges of agricultural biotechnologies, such as cisgenic GM plants. The paper offers policy-relevant input to ongoing efforts to broaden the scope of risk assessments of agricultural biotechnologies. We aim to contribute to the recognition of the complex socio-ecological, legal and political dimensions in which these technological developments are entangled as a means to acknowledge, discuss and respond to these concerns and thereby contribute to more comprehensive and responsible developments within agricultural biotechnology.