Effects of fenvalerate concentrations and its chiral isomers on bacterial community structure in the sediment environment of aquaculture ponds

To investigate the effect of chiral pesticide fenvalerate (FV) on the micro-ecological environment of aquaculture pond sediment, we used an indoor static experiment to observe the effects of FV added at different concentrations with different chiral isomers on the changes in the sediment bacterial community. The 16S rDNA high-throughput sequencing technique was used to conduct sequencing and analysis of the bacterial community structure as well as changes in aquaculture pond sediments after 4 weeks of cultivation. The results showed that the microbial alpha diversity indices (Sobs and Shannon indices) of the treated groups were significantly lower than those of the control group after 4 weeks (P < 0.05), and the values in the high-concentration group were significantly lower than those of the low-concentration group (P < 0.05). In terms of bacterial group composition, the proportion of abundance of Proteobacteria and Acidobacteria in the treated groups were greater than in the control group after 4 weeks, while the proportion of abundance of Bacteroidetes and Verrucomicrobia were lower. In the high-concentration FV treatment group, the proportion of abundance of Bacteroidetes, Acidobacteria, Chloroflexi, Nitrospinae, unclassified_k_norank, Ignavibacteriae, and Nitrospirae were significantly different from those of the other groups (P < 0.05). Principal coordinate analysis (PCoA) and ANONISIM/Adonis analysis showed that the cis-enantiomer had a stronger effect on the bacterial community as the concentration of FV increased. In addition, the linear discriminant analysis effect size (LEfSe) and linear discriminant analysis (LDA) results revealed differences in the level of enrichment of bacterial groups caused by FV at different concentrations and isomer levels. Collectively, this study showed that FV residue has a pronounced effect on bacterial communities in sediment, which becomes more significant with increasing exposure concentration. The effects of the cis- and trans-enantiomers of FV on the sediment environment are different; the cis-enantiomer has a stronger effect on the bacterial community.

     

Digitalization and environment: how does ICT affect enterprise environmental performance?

Environmental Science and Pollution Research - Despite the increasing use of digital technology in industrial production, how industrial digitalization affects the environmental performance of...     

Antibiotic accumulation,growth performance,intestinal diversification,and function of Nile tilapia (Oreochromis niloticus) feed by diets supplemented with different doses of sulfamethoxazole

Environmental Science and Pollution Research - To comprehensively investigate the effects of exposure to legal doses of sulfamethoxazole (SMZ) in Nile tilapia (Oreochromis niloticus), fishes were...     

Nutrients regeneration pathway, release potential, transformation pattern and algal utilization strategies jointly drove cyanobacterial growth and their succession

In order to better understand the contribution of nutrients regeneration pathway, release potential and transformation pattern to cyanobacterial growth and succession, 7 sampling sites in Lake Chaohu with different bloom degree were studied every two months from February to November 2018. The carbon, nitrogen (N) and phosphorus (P) forms or fractions in surface, interstitial water and sediments as well as extracellular enzymatic activities, P sorption, specific microbial abundance and community composition in sediments were analyzed. P regeneration pathway was dominated by iron-bound P desorption and phosphorus-solubilizing bacteria solubilization in severe-bloom and slight-bloom area respectively, which both resulted in high soluble reactive phosphorus (SRP) accumulation in interstitial water. However, in severe-bloom area, higher P release potential caused the strong P release and algal growth, compared to slight-bloom area. In spring, P limitation and N selective assimilation of Dolichospermum facilitated nitrate accumulation in surface water, which provided enough N source for the initiation of Microcystis bloom. In summer, the accumulated organic N in Dolichospermum cells during its bloom was re-mineralized as ammonium to replenish N source for the sustainable development of Microcystis bloom. Furthermore, SRP continuous release led to the replacement of Dolichospermum by Microcystis with the advantage of P quick utilization, transport and storage. Taken together, the succession from Dolichospermum to Microcystis was due to both the different forms of N and P in water column mediated by different regeneration and transformation pathways as well as release potential, and algal N and P utilization strategies.     

Selection of water source for water transfer based on algal growth potential to prevent algal blooms

Water transfer is becoming a popular method for solving the problems of water quality deterioration and water level drawdown in lakes. However, the principle of choosing water sources for water transfer projects has mainly been based on the effects on water quality, which neglects the influence in the variation of phytoplankton community and the risk of algal blooms. In this study, algal growth potential (AGP) test was applied to predict changes in the phytoplankton community caused by water transfer projects. The feasibility of proposed water transfer sources (Baqing River and Jinsha River) was assessed through the changes in both water quality and phytoplankton community in Chenghai Lake, Southwest China. The results showed that the concentration of total nitrogen (TN) and total phosphorus (TP) in Chenghai Lake could be decreased to 0.52 mg/L and 0.02 mg/L respectively with the simulated water transfer source of Jinsha River. The algal cell density could be reduced by 60%, and the phytoplankton community would become relatively stable with the Jinsha River water transfer project, and the dominant species of Anabaena cylindrica evolved into Anabaenopsis arnoldii due to the species competition. However, the risk of algal blooms would be increased after the Baqing River water transfer project even with the improved water quality. Algae gained faster proliferation with the same dominant species in water transfer source. Therefore, water transfer projects should be assessed from not only the variation of water quality but also the risk of algal blooms.     

自吸式文丘里洗涤器雾化液滴尺寸影响因素的实验研究

为研究雾化液滴尺寸对自吸式文丘里洗涤效率的影响,从喉部气速、液面高度差以及文丘里扩散段结构等方面,研究了自吸式文丘里洗涤器雾化液滴平均直径(D_(32))的变化规律,并与Boll模型对D_(32)的预测值进行了对比。研究表明,随着喉部气速的增加,D_(32)的实验值和预测值均呈逐渐减小的趋势,且预测值略小于实验值。另外,液面高度差的增加会导致D_(32)的减小,当气相速度增大时,D_(32)加速减小。研究发现,当喉部气速大于54.6 m/s时,A_1挡板对液相流体具有更好的雾化效果,当喉部气速小于54.6 m/s时,在环形挡板内径为46～54 mm之间存在一个最佳内径,使得雾化液滴平均直径最小,文丘里洗涤器达到最佳雾化效果。     

考虑车辆类型变化的中国乘用车排放特征

通过引入Lotka-Volterra模型预测了中国未来30年的乘用车竞争趋势;通过引入CHG、VOC、CO、SO₂、PM_2.5、NO_x6类污染物更新了全生命周期清单;并据此建立了政策影响模型和敏感性模型评估电动化、轻量化和清洁化政策情景减排效果.结果表明,乘用车市场的主要竞争力来源于新能源与传统能源的竞争,且纯电动与混合动力乘用车呈S型曲线发展,汽油乘用车占比由92%减少到1%;全生命周期中,纯电动乘用车对CHG、VOC、CO减排效益最优,为20%~85%;汽油与天然气乘用车对SO₂和PM_2.5的减排效益最优,为50.0%;3类情景下税收补贴类政策敏感性最强,CHG、VOC和CO的最优减排情景为电气化情景,PM_2.5、NO_x的最优减排情景为清洁化情景,而SO₂的最优减排情景则为整车轻量化.     

Influence of drying and calcination temperatures for Ce-Cu-Al trimetallic composite catalyst on simultaneous removal H2S and PH3: Experimental and DFT studies

This work explored the influences of the drying and calcination temperatures on a Ce-Cu-Al trimetallic composite catalyst for the simultaneous removal of H₂S and PH₃. The effects of both temperatures on the structural features and activity were examined. The density functional theory method was used to calculate adsorption energies and further analyze their adsorption behavior on different slabs. Experiments revealed suitable drying and calcination temperatures to be 60 and 500°C, respectively. The capacity reached 323.8 and 288.1 mg/g. Adjusting drying temperature to 60°C is more inclined to form larger and structured grains of CuO. Rising calcinating temperature to 500°C could increase the grain size and redox capacity of CuO to promote performance. Higher temperatures would destroy the surface structure and lead to a crystal phase transformation, which was that the CuO and Al₂O₃ were gradually recombined into CuAl₂O₄ with a spinel structure. The exposed crystal planes of surficial CuO and CuAl₂O₄ were determined according to characterization results. Calculation results showed that, compared with CuO (111), H₂S and PH₃ have weaker adsorption strength on CuAl₂O₄ (100) which is not conducive to their adsorption and removal.     

燃烧生成棕色碳的三维荧光光谱分析

模拟燃烧11 种常见物质(秸杆、木材、煤和生活垃圾等),并收集烟气中可溶于甲醇的有机产物,利用紫外-可见吸收光谱(UV-Vis)和三维荧光光谱(EEMs)对收集的甲醇可溶性有机物(MSOM)进行表征.进一步,结合非负矩阵分解法(NMF)提取三维荧光光谱主要组分的特征激发/发射光谱,根据荧光信号轮廓差异对不同种类物质进行区分,旨在建立棕色碳溯源依据.结果显示,秸杆和木材燃烧源棕色碳在紫外-可见吸收光谱上呈现相似的谱形,均在265nm处存在肩峰;瓦楞纸板和塑料燃烧源棕色碳的吸收则随波长增加单一下降.由于基本组分相同,各生物质及纸板对应的棕色碳的EEM有着相似的轮廓,NMF解析结果表明,生物质和纸板的MSOM存在3种主要荧光组分,分别为两种类腐殖质C1、C2和类蛋白质C3;煤的EEM在长波处有较强的分布,可归因于芳香类基团,由其EEM分解出M1、M2和M3荧光团,三者位置均较生物质红移.根据荧光团位置以及光谱信号轮廓特征,可对生物质和煤进行区分;泡沫、塑料袋和塑料瓶属于有机高分子材料,其EEM与生物质有较大的差别,且三者之间也存在差异,泡沫和塑料袋的MSOM含有4种荧光成分,而从塑料瓶的MSOM中只可得到两种荧光团,特征明显.     

Comparative lifecycle greenhouse gas emissions and their reduction potential for typical petrochemical enterprises in China

Petrochemical enterprises have become a major source of global greenhouse gas (GHG) emissions. Yet, due to the unavailability of basic data, there is still a lack of case studies to quantify GHG emissions and provide petrochemical enterprises with guidelines for implementing energy conservation and emission reduction strategies. Therefore, this study conducted a life cycle assessment (LCA) analysis to estimate the GHG emissions of four typical petrochemical enterprises in China, using first-hand data, to determine possible emission reduction measures. The analytical data revealed that Dushanzi Petrochemical (DSP) has the highest GHG emission intensity (1.17 tons CO₂e/ton), followed by Urumqi Petrochemical (UP) (1.08 tons CO₂e/ton), Dalian Petrochemical (DLP) (average 0.58 tons CO₂e/ton) and Karamay Petrochemical (KP) (average 0.50 tons CO₂e/ton) over the whole life cycle. At the same time, GHG emissions during fossil fuel combustion were the largest contributor to the whole life cycle, accounting for about 77.31%–94.27% of the total emissions. In the fossil-fuel combustion phase, DSP had the highest unit GHG emissions (1.20 tons CO₂e), followed by UP (0.89 tons CO₂e). In the industrial production phase, DLP had the highest unit GHG emissions (average 0.13 tons CO₂e/ton), followed by UP (0.10 tons CO₂e/ton). During the torch burning phase, torch burning under accident conditions was the main source of GHG emissions. It is worth noting that the CO₂ recovery stage has "negative value," indicating that it will bring some environmental benefits. Further scenario analysis shows that effective policies and advanced technologies can further reduce GHG emissions.