We present an automatic design process for microfluidic dilution network towards marine ecological toxicity assessment on microalgae. Based on the hydraulic–electric circuit analogy, we defined an abstract specification using computer-aided designing system. Several approaches, especially circuit partition, were applied to minimize design effort. Computational fluid dynamics (CFD) simulation was exploited to convert the electrics specification to fabrication model. We automatically designed the combinational-mixing-serial dilution microfluidics to generate parallel stepwise gradients for mixing chemicals (binary/ternary/quaternary mixture) using the present algorithm. We critically discussed design rules and evaluated the microfluidic performance by colorimetric analysis. To examine whether these microfluidic chips can be used for toxicity test on microalgae, single and joint toxic effects of heavy metals (copper, mercury, zinc, and cadmium) were examined on line. In all cases, dose-related toxic responses were successfully detected. These results provided a solution for designing resistive network using circuit partition and CFD-based optimization and a route to develop a promising user-friendly alternative for microalgae bioassays as well as cell-based screening experiments in risk assessment.

Marine pollution and monitoring have received more and more concern in recent years. Herein, a fully automatic whole-algae biosensor was designed for low-cost and fast detection of toxic contaminants in seawater. It consists of a digital microfluidic (DMF) diluter chip, an actuation element, a detector element, and a microalgae bioreporter. A feedback-control protocol based on charging-time compensation was introduced. It ensures precise actuation of the droplet with diverse salty concentrations and contents in the marine environment. The two mixer cross-split dilution engine increases the accuracy of droplet dispensing and concentration diluting. By selecting motility of P. subcordiformis as the sensor signal, the developed biosensor showed good sensitivity and robustness for a wide range of salinity (10-37 parts per thousand), temperature (0-25 degrees C), light levels (0-325 mu mol photons m(-2) s(-1)), and cell density factor (1.0-4.0). The biosensor responses were examined in the presence of copper, lead, phenol, and nonylphenol (NP). In all cases, toxic responses (i.e. dose-related inhibition of algal motion) were detected with the detection limits of 0.65 mu mol.L-1, 1.90 mu mol.L-1, 2.85 mmol.L-1, and 5.22 mu mol.l(-1) respectively. These results were obtained in a much shorter time (2 h for our biosensor vs. 24 h-10 d for growth inhibition test) and the data are consistent with previous classical studies. We thus developed a simple, rapid, and adaptable system for marine routine monitoring and early-warning detection for lab and on-site applications.

海洋污染生态毒性效应研究是认识和评价海洋环境质量现状及其变化趋势的重要依据.发展快速、有效的测试方法和指标对于防治污染、保护海洋环境具有重要意义.作者以海洋微藻运动性作为生理指标研究了典型海洋污染物的生态毒性效应.在本实验所测试的浓度范围内,铜(0～4.41μmol/L)和苯酚(0～9.03 mmol/L)分别在2 h内对亚心型扁藻(Platymonas subcordiformis)的能动性,包括运动方式、运动能力和游泳速度产生了一定的影响,且都呈现良好的剂量-效应关系.经Logistic模型拟合分析求得铜和苯酚对亚心型扁藻的2 h-EC50分别为2.21μmol/L～2.65μmol/L和4.47 mmol/L～5.71 mmol/L.在联合毒性实验中,铜和苯酚混合后,对亚心型扁藻的2h-EC50>1TU,其联合毒性效应方式表现为拮抗作用.上述结果与传统毒性试验(包括微藻72 h生长抑制试验,24 h～48 h大型蚤静止试验和96 h鱼类死亡试验)结果均是可比的,但相对所需测试时间较短,表明微藻运动性作为一种新型的生物测试指标可以对海洋污染物生态毒性(包括单一和联合毒性)进行快速、有效的评价.

Because of the crucial ecological significance of microalgae, microalgal bioassays have become one of the most demanding tests from all classic aquatic toxicity tests in regulatory frameworks. However, conventional algal tests tend to be lab-intensive and time- and space-consuming, and they have not been utilized to their full potential for routine toxicity assessments. Microfluidics should be a user-friendly alternative. Particularly, dilution to generate gradients that are appropriate for screening experiments can be precisely attained by microfluidic network in a simple and cost-/time-/space-saving way. Here, we demonstrate a microfluidics series toward routine microalgal bioassays, including pretest, single, and joint toxicity test. The chip mainly consists of upstream dilution network (single serial dilution module (logarithmic/linear gradient generator) or multiple (binary/ternary/quaternary) mixing serial dilution module) and downstream diffusible culturing module. It allows the processes of chemical liquid dilution and diffusion, microscale microalgal culture, cell stimulation, and online screening to be integrated into a single device. Electric theorems with the aid of EDA (electronic design automation) simulation were innovatively introduced to minimize design effort for such systems. Using the device, microalgae were successfully cultured and stressed on-chip. The simple assay provides multibiological trait assessments of cell division rate, autofluorescence, esterase activity, and mobile capacity. This work showed promise in developing a high-throughput microfluidic platform for microalgal bioassays as well as lab-on-a-chip screening experiments in the cell-based quantitative assessment of environmental health risks.

The long-term effects of combined divalent copper (Cu(II)) and tetracycline (TC) on the performance, microbial activity and community in a sequencing batch reactor (SBR) were investigated. The addition of Cu(II), TC or mixed Cu(II)/TC caused the decrease of the organics and nitrogen removal efficiencies, and their decreased degrees were the lowest at the addition of mixed Cu(II)/TC. The increase of mixed Cu(II)/TC concentrations in the influent did not change the antagonistic effects between Cu(II) and TC on nitrifying and denitrifying activities. Nitrifiers had higher tolerances to Cu(II), TC and mixed Cu(II)/TC than denitrifiers. Compared to the addition of Cu(II) or TC alone, the microbial community richness was higher at the addition of mixed Cu(II)/TC, while the microbial community diversity was lower. The increased protein (PN) in extracellular polymeric substances (EPS) was a protective response of bacteria to Cu(II), TC and mixed Cu(II)/TC.

The effect of salinity on the loosely bound extracellular polymeric substances (LB⁃EPS) and tightly bound extracellular polymeric substances (TB⁃EPS) from anaerobic sludge in an upflow anaerobic sludge blanket (UASB) reactor was investigated using three⁃dimensional excitation⁃emission matrix (3D⁃EEM) fluorescence spectroscopy and Fourier transform infrared (FTIR) spectra. The relationships of the LB⁃EPS and TB⁃EPS with sludge volume index (SVI) at different salinities were analyzed. As the increase of influent salinity from 0 to 8%, the LB⁃EPS and TB⁃EPS from anaerobic sludge increased from 4.94 and 12.25 mg·g-1 VSS to 41.47 and 43.04 mg·g-1 VSS, respectively, and the protein / polysaccharide (PN / PS) ratios in the LB⁃ EPS and TB⁃EPS decreased from 3.2 and 3.8 to 1.8 and 2.3, respectively. Both the LB⁃EPS and TB⁃EPS exhibited positive correlations with SVI. 3D⁃ EEM fluorescence spectroscopy results show that the tryptophan and aromatic protein⁃like peaks were present in the LB⁃EPS and TB⁃EPS at 0 ~ 8% salinity, however the humic acid⁃like peak was only found in the TB⁃EPS at 4%~8% salinity. Results of FTIR spectrometry exhibit that the increase of influent salinity resulted in the increase of the relative contents of C—O groups of polysaccharide.

The differences between biofilm and suspended sludge (S-sludge) in extracellular polymeric substances (EPS), microbial activity, and microbial community in an anoxic-aerobic sequencing batch biofilm reactor (SBBR) at different concentrations of divalent cadmium (Cd(II)) were investigated. As the increase of Cd(II) concentration from 0 to 50mgL(-1), the specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR) of biofilm decreased from 4.85, 5.22 and 45mgNg(-1) VSSh(-1) to 1.54, 2.38 and 26mgNg(-1)VSSh(-1), respectively, and the SAOR, SNOR and SNRR of S-sludge decreased from 4.80, 5.02 and 34mgNg(-1)VSSh(-1) to 1.46, 2.20 and 17mgNg(-1)VSSh(-1), respectively. Biofilm had higher protein (PN) content in EPS than S-sludge. Contrast to S-sludge, biofilm could provide Nitrobacter vulgaris, beta proteobacterium INBAF015, and Pseudoxanthomonas mexicana with the favorable conditions of growth and reproduction.

We report the use of microalgal swimming behavior as a sensor signal integrated into microfluidics for a rapid and high-throughput determination of pollutant toxicity. There are two types of chip. A poly(dimethylsiloxane) (PDMS) 12-well chip, used for optimization of experimental conditions (i.e. light level, temperature, initial cellular density and exposure time), can perform twelve parallel tests simultaneously. In a concentration gradient generator (CGG) chip, a CGG connected with diffusible chambers enables a large number of dose-response bioassays to be performed in a simple way. Microalgal swimming was set as a microfluidic bioassay signal and was evaluated as swimming manner, motile percentage (%MOT), curvilinear velocity (VCL), average path velocity (VAP) and straight line velocity (VSL). Under optimized physical conditions, the toxicities of Cu, Pb, phenol and nonylphenol (NP) towards four mobile marine microalgae, Platymonas subcordiformis, Platymonas helgolandica var. tsingtaoensis, Isochrysis galbana and Isochrysis zhanjiangensis sp. nov, were investigated. In all cases, a toxic response (i.e. a dose-related inhibition of swimming) was detected, and a time of only 2 h was needed to predict EC50 values. The 2h-EC50s showed that I. galbana was the most tolerant and that P. subcordiformis was one of the most sensitive. Based on the relative motile percentage data, the EC50 values for Cu of I. galbana and P. subcordiformis were 6.04 and 1.67 μM, respectively, while for Pb the EC50 values were 15.30 and 3.87 μM, for phenol the EC50 values were 8.69 and 6.08 mM, and for NP the EC50 values were 29.65 and 14.47 μM, respectively. Taking into account all the swimming inhibition parameters, MOT provided more sensitive EC results. The sensitivity differences between the velocity parameters (VCL, VAP and VSL) were ascribed to differences in swimming manner of the different classes of microalgae.

The long-term effects of salinity on extracellular polymeric substances (EPS), microbial activity and microbial community from biofilm and suspended sludge (S-sludge) in an anoxic-aerobic sequencing batch biofilm reactor (SBBR) were investigated. The increase of influent salinity from 0% to 8% caused the decrease of specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR) and specific nitrate reduction rate (SNRR) in biofilm from 3.89, 4.60 and 52 mg N/(g MLSS h) to 1.01, 0.83 and 18 mg N/(g MLSS h), respectively, and the decrease of SAOR, SNOR and SNRR in S-sludge from 3.57, 3.95 and 29 mg N/(g MLSS h) to 0.71, 0.61 and 9 mg N/(g MLSS h), respectively. As the salinity increased from 0% to 8%, the protein (PN) content in EPS from biofilm and S-sludge increased from 8.35 and 8.77 mg/g VSS to 90.88 and 58.63 mg/g VSS, respectively, and the polysaccharide (PS) content in EPS from biofilm and S-sludge increased from 3.05 and 4.03 mg/g VSS to 57.55 and 62.63 mg/g VSS, respectively. Nitratireductor lucknowense, Micropruina glycogenica, and Thiobacillus thioparus could grow more favorably in biofilm than in S-sludge at 0-8% salinity. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Recently, a new type of chip technology, microfluidics, has received global attention for its rapid analysis speed, low reagent consumption, small size and simple operation, etc. Based on a micro-channel network and supported by a Micro-Electro-Mechanic System (MEMS), this technology integrates all the functions of a laboratory into one small piece of chip, which is called "lab on the chip". This paper presented a brief introduction about microfluidics and its representative developments. Future prospects in the aspects of instrument miniaturization, system integration, chip materials, and detection techniques, as well as the implementation of microfluidics in aquatic environmental pollutant analysis were thoroughly discussed. Some problems faced now were put forward. With the rapid progress in the microfluidics, a universal low-cost microchip capable of high speed multi-channel detection and integrated with many kinds of detection methods would be the research focus in the future.

A 3D paper-based microfluidic device has been developed for colorimetric determination of selected heavy metals in water samples by stacking layers of wax patterned paper and double-sided adhesive tape. It has the capability of wicking fluids and distributing microliter volumes of samples from single inlet into affrays of detection zones without external pumps, thus a range of metal assays can be simply and inexpensively performed. We demonstrate a prototype of four sample inlets for up to four heavy metal assays each, with detection limits as follows: Cu (II) = 0.29 ppm, Ni(II) = 0.33 ppm, Cd (II) = 0.19 ppm, and Cr (VI) = 0.35 ppm, which provided quantitative data that were in agreement with values gained from atomic absorption. It has the ability to identify these four metals in mixtures and is immune to interferences from either nontoxic metal ions such as Na(I) and K(I) or components found in reservoir or beach water. With the incorporation of a portable detector, a camera mobile phone, this 3D paper-based microfluidic device should be useful as a simple, rapid, and on-site screening approach of heavy metals in aquatic environments.

In vitro culturing of trophozoites was important for research of Giardia lamblia (G. lamblia), especially in discovery of anti-Giardia agents. The current culture methods mainly suffer from lab-intension or the obstacle in standardizing the gas condition. Thus, it could benefit from a more streamlined and integrated approach. Microfluidics offers a way to accomplish this goal. Here we presented an integrated microfluidic device for culturing and screening of G. lambda. The device consisted of a polydimethylsiloxane (PDMS) microchip with an aerobic culture system. In the microchip, the functionality of integrated concentration gradient generator (CGG) with micro-scale cell culture enables dose response experiment to be performed in a simple and reagent-saving way. The diffusion-based culture chambers allowed growing G. lamblia at the in vivo like environment. It notable that the highly air permeable material of parallel chambers maintain uniform anaerobic environment in different chambers easily. Using this device, G. lamblia were successfully cultured and stressed on-chip. In all cases, a dose-related inhibitory response was detected. The application of this device for these purposes represents the first step in developing a completely integrated microfluidic platform for high-throughput screening and might be expanded to other assays based on in vitro culture of G. lamblia with further tests. (C) 2013 Elsevier Inc. All rights reserved.

In this paper,ultrasonic-enhanced ozone technology was adopted to treat papermaking wastewater.The effects of ozone gas flow,pH value,ultrasonic power and reaction time on COD removal rate were investigated.The experiments showed that the COD removal rate increased with the increase of the ultrasonic power,and found the optimum ozone gas flow of 0.2 m3/h and the optimum pH of 8.Under the condition of influent COD concentration of 733.4 mg/L,pH value of 8,ozone gas flow of 0.2 m3/h,the ultrasonic power of 100 W,the COD removal rate reached 87.3% by ultrasonic-enhanced ozone technology,while it was only 36.3% by ozone technology at 30min.The former with obvious advantages is higher 51% than the latter.

Reaction completely,oxidation by ozone oxidation ability and no secondary pollution and so on.Ozone pollutants have some limitations,however,and wastewater treatment with ultrasound enhancement ozone in recent years this technology gradually developed,providing new solutions for wastewater.This major study ozone intake flow,effects of ultrasonic power on COD removal efficiency.Experiments show that ultrasonic enhancement of ozonation system synergy.

MBR performance has been investigated with activated and granular sludges,respectively.Through comparing the flux variation as well as membrane fouling status in both MBR systems,the method of improving MBR performance has been studied.Experimental results indicate that the permeate flux of MBR with granular sludges is much higher than that of the system with conventional activated sludges under same operational conditions.MBR system by using granular sludges will greatly reduce the energy consumption as compared with activated sludges system.Furthermore,as granular sludges MBR obviously decreases the possibility of membrane fouling,it can steadily run for a long time without cleaning as compared with conventional activated sludges MBR.

Simulated experiments were performed in laboratory.In these experiments,effects of heavy metal(copper,cadmium,zinc and lead) coupled with Ulca pertusa on marine inorganic carbon system and CO2 fluxes were investigated.The results indicated that concentration changes(Δ) of inorganic carbon system were correlated with the concentrations and kinds of heavy metal(t=7d).In the heavy metal groups of low concentration(<1μmol·L-1),DIC、HCO-3and Pco2 significantly decreased comparing to the control experiment data(P<0.01).When the infusions of copper and cadmium were higher than the "critical concentration",the above mentioned parameters increased comparing to the control experiment data and their increments followed the uptrend with increasing heavy metal concentrations.As for zinc and lead,when they were 50μmol·L-1,decreasing trend of inorganic carbon in sea water was still found.Moreover,the results indicated that CO2 sink/source pattern might be controlled by the concentrations and kinds of heavy metal.When the infusions of copper and cadmium were lower than that critical concentration,the corresponding sea waters were presented as sinks to atmospheric CO2.These sinks would probably convert into CO2 sources after the dose of copper and cadmium exceeding the critical concentration and their release fluxes of CO2 augmented along with the increasing infusions of heavy metal.For the groups of zinc and lead,in the range of our experiment dose,the sea waters were always present as atmospheric CO2 sinks.However,when the concentrations of zinc and lead were higher than 15μmol·L-1 and 20μmol·L-1,respectively,their carbon sink strength became less than that of the control experiment(P<0.05).

The practice teaching is an effective means for enforcing quality education and training the practical and innovative ability of students.The building and improving of practice base is the best way to ensure and improve the quality of practise teaching.Combining with the subject features of environmental science,the index systems are proposed for assessing the quality of practice base of environmental science from the foundation and management aspects.

近十余年来,海洋胶体的研究越来越引起人们的兴趣和关注,因为人们逐渐认识到胶体在海洋生物地球化学循环中可能起着非常重要的作用.

The acclimation research of two kinds of activated sludge, one of which is from the coast and the other is from the common wastewater treatment plant, has been compared. The results show that after proper acclimation, salt-tolerant sludge with high degradation capacity can be formed from these two kinds of sludge, and can be used for treating salt-containing wastewater effectively. In the biological treatment process, when the NaCl concentration of the sludge from the coast is 35 000 mg/L, its CODCr volumetric loading is 1.8 kg/(m3·d), and CODCr removal rate of the effluent water is above 97%; while by contrast with common sludge, the NaCl concentration is 15 000 mg/L, the CODCr volumetric loading is 1.55 kg/(m3·d), and effluent CODCr removal rate is above 94%. At the same time, the characteristics of acclimation process, the biologically evolutionary process and the anti-shock performance of the two kinds of sludge are compared. Compared with the common sludge, the seaside sludge has the characteristics of short acclimation period, strong anti-shock performance and so on.