Heavy metals in coastal sediments in Guipuzcoa (Spain)∗

Surficial sediment samples were wet digested (HNO₃‐HCI‐HF) and analysed by atomic absorption spectroscopy. The background values in the area, and the Pollution Index Load in the sampling points were calculated. Metal inputs of continental origin are specially important in Deva, Oria and Urola river mouths.     

The estimation of bioconcentration factors of aromatic hydrocarbons by high‐performance liquid chromatography

The determination of Bioconcentration Factors (BCF) via HPLC capacity factors (k') has been studied, including the effect of column type and mobile phase composition on the correlation between log BCF and log k’. Values of BCF correlate well with the phenylsilica column capacity factors. The phenylsilica column followed by C18 column give better correlations than either C8 or C2 column. The use of HPLC with phenylsilica as stationary phase and methanol‐water as mobile phase in the prediction of BCF can be at least as good or better than the use of n‐octanol/water partitioning system. There are no significant differences in the correlations between log k’ and log BCF with the changes of methanol concentration in the mobile phase, and it seems that a high proportion of methanol in the eluent is required to obtain good results.     

Validation of liquid nitrogen vaporisation rate by small scale experiments and analysis of the conductive heat flux from the concrete

The vaporisation of a liquid nitrogen pool spilled on concrete ground was investigated in small scale field experiments. The pool vaporisation rate and the heat transfer from the concrete ground were measured using a balance and a set of embedded heat flux sensors and thermocouples. The ability to predict the concrete's thermal properties based on these measurements was investigated. This work showed that a simple, one-dimensional theoretical model, assuming heat conduction through a semi-infinite ground with ideal contact between the cryogenic liquid and the ground, commonly used to describe the heat transfer from a ground to the LNG, can be used to match the observed vaporisation rate. Though estimated parameters, thermal conductivity and thermal diffusivity, do not necessary represent real values. Although the observed vaporization rate follows a linear trend, and thus can be well represented by the model, the overall model prediction seems to be overestimated. The temperature profile inside the concrete is slightly over-predicted at the beginning and under-predicted at later stage of the spill. This might be an effect of the dependence of the concrete's thermal properties on the temperature or may indicate an incorrect modelling and a varying temperature of the ground surface.     

Mycelial culture of wild Inonotus hispidus parasitizing the jujube tree and the cultivation conditions of its fruit body on rice medium北大核心CSCD

Inonotus hispidus is a kind of rare medicinal fungus, and its natural resources are very scarce. Currently, the artificial cultivation technology of I. hispidus is not completely developed, and this reflects on its extremely low biological conversion rate and long cultivation period. In order to improve the bioconversion rate and shorten the production cycle of I. hispidus, we first analyzed the mycelia culture conditions of the collected I. hispidus, and then we further explore the method of domesticated cultivation of its fruiting body in rice medium. During the process of mycelial culture, the suitable temperature, pH, carbon source, and nitrogen source for mycelial growth were selected using the mycelial growth rate as index. During the domesticated cultivation of the fruiting body, the suitable culture medium for its growth was selected using the bioconversion rate as index. Screening results of mycelial culture conditions showed that the optimal culture conditions for the growth of mycelium of the wild I. hispidus were: temperature of 25 °C, initial pH of 6.0, glucose as the carbon source, and yeast extract powder as the source of nitrogen. The results of the domesticated cultivation showed that the biotransformation rate of I. hispidus was higher when using rice as the main medium substrate. The optimal cultivation conditions were: a 0.2% yeast extract content in the nutrient solution, a 1:1.6 ratio of rice to nutrient solution, and a 4 mL inoculum of the liquid strain. Under these conditions, it took about 4 days for the mycelium to grow over the cultivation medium. The time required for the differentiation of the primordium to form fruit bodies was about 20 days, and the bioconversion rate reached 28.70% ± 5.05%. The results of this study indicate the feasibility of using rice as the main substrate for the cultivation of I. hispidus, and it also provide new insights for the finding of new cultivation substrates for other rare medicinal fungi. © 2018 Science Press. All rights reserved.     

液液萃取-气相色谱/串联质谱法测定水中五氯酚及其钠盐

采用液液萃取处理水样,用气相色谱-串联质谱法测定样品中五氯酚及其钠盐,通过优化测定条件,使方法在1.00μg/L~500μg/L范围内线性良好。检出限和定量限分别为1.00μg/L和5.00μg/L,空白水样五氯酚钠3个质量浓度水平的加标回收率为89.8%~98.4%,5次平行试验测定结果的RSD为5.5%~10.7%。     

盐雾腐蚀及其试验中需要注意的几个问题分析

本文介绍了产品进行盐雾腐蚀试验的必要性,对中性盐雾试验、醋酸盐雾试验、铜盐加速醋酸盐雾试验、交变盐雾试验分别进行了描述。重点介绍了盐雾试验中需要注意的几个问题:试样预处理、试样的放置、盐溶液pH值及试验温度,并探讨了一些对应的预防措施。     

养殖废水中9种大环内酯及林可酰胺类抗生素的同时测定及分析方法研究

采用固相萃取-超高效液相色谱三重四极杆质谱联用法,建立了同时测定养殖废水中9种大环内酯及林可酰胺类抗生素的方法,并对样品pH值、保存时间、洗脱溶剂、上样流速及过滤材质等进行了优化。测定结果表明,pH值为6,过滤材质为聚丙烯（GHP）,上样速度为5 mL/min时,9种抗生素的加标回收率最优,为71.4%～126%,相对标准偏差最小,为2.4%～7.1%,标准曲线的线性最好,相关系数为0.998 5～0.999 5,检出限为0.78～1.22 ng/L。该方法灵敏度高、检出限低、测定结果准确,能够广泛应用于养殖废水中大环内酯及林可酰胺类抗生素残留量的监测分析。     

环境样品中汞形态分析技术的进展

汞的毒性、环境行为、生物有效性不仅跟其浓度有关,还决定于其化学形态,因此汞的形态分析在环境科学中具有重要意义。样品前处理几乎是汞形态分析研究中不可或缺的步骤,而色谱和光谱/质谱联用技术是目前普遍采用的分离检测方法。文章对近十年来这些方面的研究进展进行了综述,主要包括样品的前处理方法如酸/碱溶剂萃取、微波辅助萃取、固相萃取、固相微萃取、单滴微萃取、分散液液微萃取等,以及色谱(液相色谱、气相色谱)和毛细管电泳与光谱/质谱(紫外可见光谱、原子吸收光谱、原子荧光光谱、等离子体质谱等)的联用技术在汞化合物形态分析中的应用情况。最后提出今后应重点研究建立高效、简便的前处理方法,发展高分离度、高灵敏度、高速度的分离检测联用技术,以便更好地对汞的形态进行分析监测。     

Evaporating liquid flow in a channel (An integral model based on shallow water flow approximation)

Liquefied Natural Gas (LNG) storage facilities generally include channels to convey potential spills of the liquid to an impoundment. There is increasing concern that dispersion of vapors generated by flow of LNG in a channel may lead to higher than limit vapor concentrations for safety at site boundary from channels that may be close to the dike walls. This issue is of recent concern to regulatory agencies, because the calculation of vapor hazard distance(s) from LNG flow in a channel is not required under existing LNG facility siting standards or regulations.An important parameter that directly affects the calculated LNG vapor dispersion distance is the source strength (i.e., the rate of vaporization of LNG flow from the wetted channel surfaces, as a function of spatial position and time). In this paper a model is presented which considers the variation of the depth of the flowing LNG with spatial location and time, and calculates the spatial and temporal dependence of the mass rate of vapor generation. Self similar profiles for the spatial variation of the thermal boundary layer in the liquid wetted wall and liquid depth variation are assumed. The variation with time of the location of the liquid spread front and the evaporation rate are calculated for the case of a constant LNG spill rate into a rectangular channel. The effects of two different channel slopes are evaluated. Details of the results and their impact on dispersion distances are discussed.     

浅谈简化测定总磷的方法

采用简单快速的方法消解水体中浊度或色度的干扰,在制备总磷标准时可省略消解操作步骤,实验结果不受影响。