Strategies for monitoring the emerging polar organic contaminants in water with emphasis on integrative passive sampling

Although polar organic contaminants (POCs) such as pharmaceuticals are considered as some of today's most emerging contaminants few of them are regulated or included in on-going monitoring programs. However, the growing concern among the public and researchers together with the new legislature within the European Union, the registration, evaluation and authorisation of chemicals (REACH) system will increase the future need of simple, low cost strategies for monitoring and risk assessment of POCs in aquatic environments. In this article, we overview the advantages and shortcomings of traditional and novel sampling techniques available for monitoring the emerging POCs in water. The benefits and drawbacks of using active and biological sampling were discussed and the principles of organic passive samplers (PS) presented. A detailed overview of type of polar organic PS available, and their classes of target compounds and field of applications were given, and the considerations involved in using them such as environmental effects and quality control were discussed. The usefulness of biological sampling of POCs in water was found to be limited. Polar organic PS was considered to be the only available, but nevertheless, an efficient alternative to active water sampling due to its simplicity, low cost, no need of power supply or maintenance, and the ability of collecting time-integrative samples with one sample collection. However, the polar organic PS need to be further developed before they can be used as standard in water quality monitoring programs.     

Application of passive sampling devices for screening of micro-pollutants in marine aquaculture using LC-MS/MS

Knowledge on the presence of micro-pollutants, in particular emerging contaminants, such as pharmaceuticals, biocides or some pesticides, in semi-enclosed coastal areas, where fish farms are installed, is very limited. This article shows data on the presence of micro-pollutants over 1 year monitoring campaign carried out in a fish farm placed on the Mediterranean Sea. With this work, the results of the development of an analytical procedure which, makes use of passive sampling techniques (with polar organic chemical integrative samplers, POCIS, pharmaceutical configuration) and of the LC-QLIT-MS system, are presented. The development of the analytical procedure entail laboratory-based calibration with the samplers POCIS, for calculating uptake rates and sampling rates of compounds representative of a wide range of polarity (4.56 ≥ log K_ow ≥ −0.12). The uptake of the target compounds in the sampler POCIS, follows a linear pattern for most compounds, and sampling rates varied from 0.001 to 0.319 l/d. The calibration experiments have shown that POCIS pharmaceutical configuration could be used for sampling other non-target compounds, such as pesticides and biocides with a log K_ow ≤ 4. The sampling rates for each selected compound were obtained using spiked seawater for further estimation of time-weighted average (TWA) concentration of micro-pollutants in the water column, during the field study. An analytical method was developed with the LC-QLIT-MS system and validated to ensure a satisfactory performance for the detection of the target micro-pollutants in water. The limits of detection (LODs) achieved were between 0.01 and 1.50 μg/l. During the monitoring campaign, among the selected compounds, metronidazole, erythromycin, simazine, atrazine, diuron, terbutryn, irgarol, trimethoprim, carbaryl, flumequine, TCMTB and diphenyl sulphone (DPS) were detected. Most of target compounds found were at average concentrations which ranged from 0.01 to 75 ng/l. Irgarol, simazine, diuron, atrazine and DPS were the micro-pollutants most frequently detected over the period of the monitoring programme carried out.     

Optimization of FLEC-SPME for field passive sampling of VOCs emitted from solid building materials

The FLEC^®-SPME sampler, described in a previous paper, consists of an emission cell coupled with solid phase microextraction (SPME) for passive sampling of VOCs emitted from building materials. It represents an interesting alternative to standard dynamic sampling protocol as it is easier to implement. If standard dynamic sampling determines emission rates, passive FLEC^®-SPME aims to the determination of the concentration in air at the material surface. That could be assumed provided that material/air equilibrium is reached. Thus, VOCs emission kinetics were studied for 3 different materials (pine wood panel, carpet and PVC floor) to determine equilibrium times. Then, the relevance of the method has been assessed using new materials through a 3-day emission test. Qualitative results were compared to those obtained from the standard method to check the ability of FLEC^®-SPME to detect the most toxic compounds, named “VOCs of interest” and listed in the French regulation. Minor differences were observed, so this methodology seems promising, especially for field studies aiming in the identification of VOCs sources in buildings. Moreover, the concentration at the material surface combined to emission modeling could be used to predict indoor VOCs concentrations helping in indoor air quality diagnostic.     

Real-time acoustic classification of sperm whale clicks and shipping impulses from deep-sea observatories

The automated real-time detection and classification of cetacean and anthropogenic sounds from deep-sea observatories can play a key role to study cetaceans in the field, to quantify the impact of anthropogenic sounds or to initiate mitigation measures during potentially harmful human activities. In the area of the NEMO-ONDE deep-sea observatory, sperm whales are often present together with heavy shipping. The spatial coincidence of both sound sources allows for the long term monitoring of their interaction. Some ships produce impulsive sounds and the automated separation of these impulses from sperm whale clicks is not a trivial task. As part of a detection, classification and localisation system for acoustic data from marine observatories, we present four modules performing the automated real-time classification of clicks from sperm whales and impulsive sounds produced by ships. First, two modules detect segments that contain impulsive sounds within a specifiable frequency band and return the impulses’ positions. Then, two modules classify the detected impulses as sperm whale clicks or ship impulses. Finally, at the level of 22 s segments, the classification outputs from individual impulses are combined into a decision on the presence of sperm whale clicks or ship impulses. The modules’ reliability was tested on data from the NEMO-ONDE observatory. Training and testing data were separated by more than 2 months, enabling to assess the consistency of the predictions over the long term. The automated separation between segments of the two classes was high with area under the ROC curve (AUC) values between 0.94 and 0.98.     

Estimating whale density from their whistling activity: Example with St. Lawrence beluga

A passive acoustic method is developed to estimate whale density from their calling activity in a monitored area. The algorithm is applied to a loquacious species, the white whale (Delphinapterus leucas), in Saguenay fjord mouth near Tadoussac, Canada, which is severely affected by shipping noise. Beluga calls were recorded from cabled coastal hydrophones deployed in the basin while the animal density was estimated visually from systematic observations from a fixed-point on the shore. Beluga calling activity was estimated from an algorithm extracting the call events in time-frequency space, while simultaneously tracking the masking intensity resulting from local shipping noise. The activity index was summarized in 15- and 30-min bins using four different metrics. For bins containing more than 40% of valid data, the metrics were compared to the corresponding visual observations. The estimated mean acoustic detection range generally exceeded the fjord width, and extended to the whole ∼3-km long monitored area under low-noise conditions. The significant linear relations of the visual estimates with the calling activity metrics allowed assessing expected number of visually detected belugas in the basin from a weighted regression model, with a mean standard error of 7.1%.     

激光等离子体无源电探针探测及光谱诊断的比较分析

提出一种利用无源电探针探测激光焊接光致等离子体的方法。采用光电同步采集系统对激光焊接光致等离子体进行研究,利用无源电探针和光纤式光谱仪探测光致等离子体,利用等离子鞘层理论分析电信号,并运用相对光强法计算出光致等离子体的电子温度,比较同步光电信号分析结果。将不涂覆表面物质以及表面分别涂覆KF和TiO₂三种情况下的计算结果进行对比,对影响结果准确性的因素进行分析。研究结果表明通过无源探针法计算等离子体温度与光谱信号计算结果基本吻合,准确度受等离子体离子质量的影响。无源电探针法能够反映激光焊接光致等离子体内温度变化,具有较好的实时性,可以作为激光等离子体监测手段。     

Corrosion of Nickel-based Alloy G30 in the Stratum Water Containing H2S/CO2

The influences of temperature and CO2 pressure on the corrosion of nickel-based alloy G30 in the stratum water containing H2S/CO2 were investigated with the aid Mott-Schottky analysis and scanning electron microscopy（SEM） of electrochemical impedance spectroscopy（EIS）, The results indicate that alloy G30 is in the passive state in the stratum water, which is related to the formation of the passive film on its surface. This passive film can significantly protect the substrate from further corrosion. And the film protection is enhanced with decreasing temperature and CO2 pressure. Auger electron spectrometry（AES） and X-ray photoelectron spectrometry（XPS） results reveal that the passive film shows the double-layer structure, i.e. the inner chromium oxide and the outer iron/nickel spinel oxides or hydroxides with Mo oxides dispersing throughout the inner and outer scale.     

基于星载辐射计AMSR-E不同波段的北极海冰折射系数提取

海冰折射系数是一个重要的地球物理参数。利用Hong Approximation(HA)算法和星载辐射计AMSR-E数据,基于不同微波频段(6.9,10.7,23,37,89 GHz)实现北极地区不同季节海冰折射系数反演。首先对反演所用关键数据海冰密集度反演算法的系点进行优化,反演结果与验证数据平均偏差分别为3.00%和-0.50%,低于其它常用算法。结果表明：冬季一年冰和夏季海冰的折射系数反演结果在所有微波频段的平均值范围为(1.78~1.75)和(1.72~1.70),与前人研究结果基本一致,但冬季多年冰在较高频率的折射系数与前人结果偏差较大,高于10.7 GHz的微波频段不能用于冬季多年冰折射系数的提取;综合利用不同波段海冰折射系数反演结果能够有效识别沿岸冰间湖(比如冬季6.9 GHz),区分多年冰与一年冰(冬季89 GHz),并能确定多夏季海冰边缘融化范围(夏季6.9 GHz)。     

A 12.1-W SESAM mode-locked Yb:YAG thin disk laser

Pumped by a 940 nm fiber-coupled diode laser, a passively mode-locked Yb:YAG thin disk oscillator was demonstrated with a semiconductor saturable absorber mirror(SESAM). 12.1 W mode-locked pulses were obtained with pulse duration of 698 fs at the repetition rate of 57.43 MHz. Measurement showed that the beam quality was close to the diffraction limit.     

Investigation of the Limit of Detection of an Infrared Passive Remote Sensing and Scanning Imaging System for Pollution GasEI北大核心CSCD

NECL could be used to estimate the limit of detection of the infrared passive remote sensing system. It was an important indicator of the sensitivity of the system. The theoretical equation of the NECL according to the atmospheric infrared radiation transfer model showed that NECL related to NESR, the brightness temperature of background and pollution gas, and the absorption coefficient of pollution gas. The remote sensing of SF6 was done. The limit of detection of the system at the different brightness temperature of background and pollution gas could be calculated. False color image of NECL was given from the measured data. The results show that NECL decreases rapidly by increasing the difference in brightness temperature of the background and pollution gas, the value of NECL was down to 10(-2) order of magnitude when the brightness temperature difference was equal to 30 K. False color image of NECL contributes to the discrimination of the limit of detection of the system in the complex background.