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Evaluation of Inoculum Sources for Aerobic Treatment of 2,3,4-Trifluoroaniline During Start-up and Shock 全文
2019
Zhao, Zhi-Qing | Shen, Xiao-Li | Zheng, Tu-Cai | Abbas, Ghulam | Fan, Rui | Li, Yan-Mei
Contamination with fluoroaromatics (FAs), particularly polyfluorinated aniline, is becoming a serious environmental problem worldwide. To shorten the start-up time, and increase the stability of treatment systems, this work focused on the effects of three seeding sources on treatment performances of 2,3,4-trifluoroaniline (2,3,4-TFA) during start-up and shock, as well as the acclimated strategy. After 246–323 days of acclimation in a stepwise feeding according to the inhibition degree, three sequencing batch reactors (SBRs) successfully achieved efficient removal, i.e., 300.00 mg/L of 2,3,4-TFA, with over 95.00% of degradation efficiency and 60.00–80.00% of defluorination rates. The sludge obtained from the fluorizated hydrocarbon wastewater treatment plant(FHS) without prior exposure to fluoroaniline was determined to be optimal, based on the observed shortest start-up time of 246 days, the highest defluorination rate of 70.00–80.00%, the fastest recovery time of 7 days after shock, and the highest microbial diversity with nine dominant bacterial groups. Furthermore, compared with the sludge obtained from pharmaceutical wastewater containing part of municipal wastewater treatment plant(PMS), the seeding source used in treating the comprehensive wastewater in industrial park (CIS) exhibited earlier defluorination reaction, higher defluorination rate and microbial diversity, but lower shock resistance. High-throughput sequencing demonstrated that microbial diversity was dependent on the origin of the inoculum after acclimation. We identified two predominant phyla in PMS, namely, Deinococcus-Thermus (24.43%) and Bacteroidetes (18.44%), whereas these were Acidobacteria and Chloroflexi in FHS and CIS. During the shock of 400 mg/L 2,3,4-TFA, the predominant bacteria norank_f_Blastocatellaceae and norank_f_Methylobacteriaceae disappeared, and the defluorination reaction hardly occurred, indicating that the bacterial genera could contribute to the defluorination reaction.
显示更多 [+] 显示较少 [-]Comparison of air pollution in Shanghai and Lanzhou based on wavelet transform 全文
2019
Su, Yana | Sha, Yongzhong | Zhai, Guangyu | Zong, Shengliang | Jia, Jiehua
For a long-period comparative analysis of air pollution in coastal and inland cities, we analyzed the continuous Morlet wavelet transform on the time series of a 5274-day air pollution index in Shanghai and Lanzhou during 15 years and studied the multi-scale variation characteristic, main cycle, and impact factor of the air pollution time series. The analysis showed that (1) air pollution in the two cities was non-stationary and nonlinear, had multiple timescales, and exhibited the characteristics of high in winter and spring and low in summer and autumn. (2) The monthly variation in air pollution in Shanghai was not significant, whereas the seasonal variation of air pollution in Lanzhou was obvious. (3) Air pollution in Shanghai showed an ascending tendency, whereas that in Lanzhou presented a descending tendency. Overall, air pollution in Lanzhou was higher than that in Shanghai, but the situation has reversed since 2015. (4) The primary cycles of air pollution in these two cities were close, but the secondary cycles were significantly different. The aforementioned differences were mainly due to the impact of topographical and meteorological factors in Lanzhou, the weather process and the surrounding environment in Shanghai. These conclusions have reference significance for Shanghai and Lanzhou to control air pollution. The multi-timescale variation and local features of the wavelet analysis method used in this study can be applied to varied aspects of air pollution analysis. The identification of cycle characteristics and the monitoring, forecasting, and controlling of air pollution can yield valuable reference.
显示更多 [+] 显示较少 [-]Phytoplankton Cultures for Tannin Biodegradation 全文
2019
Silva, S. B. | Pádua, R. M. | Barbosa, F. A. R. | Silva, M. A. N. | Azevedo, F. R. | Magalhães, Sergia Maria Starling
Tannins are special plant metabolites used in leather processing that act as pollutants. These substances are toxic to aquatic biota and can cause cell rupture. These harmful effects make the treatment of tannery wastewater difficult. Phytoplankton species are community components that are rarely considered in the biodegradation of organic compounds. However, in association with bacteria, these organisms can improve the biodegradation of pollutants by different mechanisms. The aim of the present study was to evaluate the potential of non-axenic cultures of Chlorella vulgaris containing Lactobacillus casei and Synechococcus sp. containing Rhizobium rosettiformans and Sphingomonas koreensis to biodegrade tannic acid (TA). Cultures in BG-11 medium containing TA (250 mg L⁻¹) were incubated under a photoperiod or in the dark and monitored for 96 h. The cultures with added TA grew more than the control cultures under both the photoperiod and dark conditions. A reduction in the TA concentration and the TA metabolite gallic acid was observed under both conditions. Ellagic acid was identified and demonstrated resistance to biodegradation under the evaluated conditions, and neither of the other metabolites was detected. BG-11 culture medium is poor in organic material; therefore, microalgae and cyanobacteria contribute to bacterial metabolism. Under experimental conditions, phytoplankton species seem to contribute to the biodegradation of tannin residues, and in natural environments, they may aid in the bioremediation of sites contaminated by these pollutants.
显示更多 [+] 显示较少 [-]Distribution and health risk assessment of Cd and Pb in two marine fishes (Haemulopsis axillaris and Diapterus peruvianus) from the Eastern Pacific 全文
2019
Spanopoulos-Zarco, Pamela | Ruelas-Inzunza, Jorge Ricardo | Meza-Montenegro, María Mercedes | Bojórquez-Leyva, Humberto | Páez Osuna, Federico
The aim of this study was to determine the distribution of cadmium (Cd) and lead (Pb) in muscle and liver tissue of Haemulopsis axillaris and Diapterus peruvianus from the Eastern Pacific in Mexico and to assess the health risk to consumers. Fish were collected as bycatch on the continental shelf between the coasts of Sinaloa and Guerrero (Eastern Pacific). Cd and Pb were quantified in muscle and liver tissue using graphite-furnace atomic absorption spectrophotometry (GF-AAS).Concentration of Cd was greater in muscle tissue than in liver tissue; with Pb, however, the opposite pattern was found. The highest concentration of Cd (0.177 μg g⁻¹) was found in muscle tissue of H. axillaris from Sinaloa. For Pb, the highest level (0.692 μg g⁻¹) was found in the liver tissue of H. axillaris also from Sinaloa. Levels of Cd and Pb in muscle tissue were both below Mexican Guidelines (0.5, 1.0 μg g⁻¹ wet weight for Cd and Pb respectively) and International Guidelines. The hazard index (HI) for both metals in the edible portion of studied considering metal levels in the edible portion and the rate of fish consumption by the Mexican population (in adults and children) was less than 1 (HI < 1), values which do not represent a health risk to consumers.
显示更多 [+] 显示较少 [-]Profiling of main metabolites in root exudates and mucilage collected from maize submitted to cadmium stress 全文
2019
Lapie, Clémentine | Leglize, Pierre | Paris, Cédric | Buisson, Tatiana | Sterckeman, Thibault
Profiling of main metabolites in root exudates and mucilage collected from maize submitted to cadmium stress 全文
2019
Lapie, Clémentine | Leglize, Pierre | Paris, Cédric | Buisson, Tatiana | Sterckeman, Thibault
The aim of this study was to characterize qualitatively and quantitatively the composition of the main rhizodeposits emitted from maize (Zea mays) under Cd stress, in order to discuss their role in Cd availability and tolerance. Maize was grown for 6 weeks in sand at four Cd exposure levels (0, 10, 20, and 40 μM Cd in nutrient solution) and two types of rhizodeposits were collected at the end of cultivation period. Mucilage and other molecules adhering to rhizospheric sand were extracted with a buffer before root exudates were collected by diffusion into water. Total carbon, proteins, amino acids, and sugars were analyzed for both rhizodeposit types and about 40 molecules were identified using GC-MS and LC-MS. Cadmium effect on plant morphology and functioning was slight, but consistent with previous works on Cd toxicity. However, rhizodeposition did tend to be impacted, with a decrease in total carbon, sugars, and amino acids correlating with an increasing Cd content. Such a decrease was not noticeable for proteins in root exudates. These observations were confirmed by the same trends in individual compound contents, although the results were generally not statistically significant. Many of the molecules determined are well-known to modify, whether directly or indirectly, Cd speciation and dynamics in the soil and could play a role in Cd tolerance.
显示更多 [+] 显示较少 [-]Profiling of main metabolites in root exudates and mucilage collected from maize submitted to cadmium stress 全文
2019
Lapie, Clémentine | Leglize, Pierre | Paris, Cédric | Sterckeman, Thibault | Buisson, Tatiana | Laboratoire Sols et Environnement (LSE) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | Laboratoire d'Ingénierie des Biomolécules (LIBio) ; Université de Lorraine (UL) | Plateau d’Analyse Structurale et Métabolomique (PASM) ; Université de Lorraine (UL)
The aim of this study was to characterize qualitatively and quantitatively the composition of the main rhizodeposits emitted from maize (Zea mays) under Cd stress, in order to discuss their role in Cd availability and tolerance. Maize was grown for 6weeks in sand at four Cd exposure levels (0, 10, 20, and 40M Cd in nutrient solution) and two types of rhizodeposits were collected at the end of cultivation period. Mucilage and other molecules adhering to rhizospheric sand were extracted with a buffer before root exudates were collected by diffusion into water. Total carbon, proteins, amino acids, and sugars were analyzed for both rhizodeposit types and about 40 molecules were identified using GC-MS and LC-MS. Cadmium effect on plant morphology and functioning was slight, but consistent with previous works on Cd toxicity. However, rhizodeposition did tend to be impacted, with a decrease in total carbon, sugars, and amino acids correlating with an increasing Cd content. Such a decrease was not noticeable for proteins in root exudates. These observations were confirmed by the same trends in individual compound contents, although the results were generally not statistically significant. Many of the molecules determined are well-known to modify, whether directly or indirectly, Cd speciation and dynamics in the soil and could play a role in Cd tolerance.
显示更多 [+] 显示较少 [-]An experimental study to investigate typical temperature conditions in fuel tanks of European vehicles 全文
2019
Grigoratos, Theodoros | Martini, Giorgio | Carriero, Massimo
Vehicular evaporative emissions have been recognized as an important source of volatile organic compounds to the environment and are of high environmental concern since these compounds have been associated to the formation of surface ozone and secondary organic aerosols. Evaporative emissions occur during any vehicle operation. In Europe, a revised legislative test procedure has been recently introduced to better control evaporative emissions during parking. However, emissions related to normal driving conditions—the so-called running losses—have received less attention compared with the other categories. The current study aims at giving some insights to the prevailing temperature conditions in fuel tanks of typical European vehicles during normal driving operation. The effects of ambient air temperature, trip duration, vehicle speed, and fuel tank level on the temperature reached by the fuel inside the tank under different real-world operating conditions were studied. Tank temperature can exceed 40 °C depending on ambient and driving conditions. Ambient temperature was found to be the most important parameter affecting the tank temperature. Trip duration and driving pattern may also have an influence on the tank temperature particularly when long trips combined with high vehicle speed are examined. Additionally, the difference between tank and ambient temperature was examined during the individual trips and was found to vary between 1 and 10 °C depending on the testing conditions. The most important parameters affecting the delta temperature were found to be the trip duration and the maximum vehicle speed. Finally, the purging strategy of two of the test vehicles was monitored, and the parameters affecting the purging flow rate were investigated. No strong correlation between the canister flow rate with ambient temperature, vehicle speed, or fuel level was observed in either of the tested vehicles. Substantially different canister flow rate levels between the two vehicles point to different purging strategies.
显示更多 [+] 显示较少 [-]Efficient removal of copper ions using a hydrogel bead triggered by the cationic hectorite clay and anionic sodium alginate 全文
2019
Tong, Dongshen | Fang, Kai | Yang, Haiyan | Wang, Jie | Zhou, Chunhui | Yu, Weihua
Sodium alginate (SA) is a linear biopolymer, which is the nontoxic, biodegradable, and rich in carboxyl and hydroxyl groups. In the paper, the SA-based hydrogel bead was prepared by the cationic hectorite clay and anionic sodium alginate with a simple ionic gelation method under freeze-drying, and the adsorption properties were evaluated by the removal of copper ions from aqueous solutions. The composites were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm (BET), thermal analysis (TG), and Fourier transform infrared spectroscopy (FT-IR). The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data and the Langmuir, Freundlich, Dubinin–Radushkevich (D-R), and Temkin models were applied to describe the adsorption isotherms. The results showed that the adsorption process was found to follow the Freundlich isotherm model and the maximum sorption capacity was observed to be 160.28 mg/g under the initial concentration from 10 to 700 mg/L at 45 °C. Adsorption kinetics data fitted well with pseudo-second-order rate model. The porous structure of the composite was responsible for the adsorption of Cu²⁺ ions. But the adsorption ability could be improved by pH. Finally, the adsorption mechanism was suggested. Graphical abstract
显示更多 [+] 显示较少 [-]A web-based GIS system for wildlife species: a case study from Khouzestan Province, Iran 全文
2019
Obeidavi, Zeinab | Rangzan, Kazem | Kabolizade, Mostafa | Mirzaei, Rouhollah
Recent efforts to aggregate, process, and use biodiversity information have appended novel opportunities and challenges for the field, and a rapid increase in studies that integrate and analyze data in the biological-ecological realm. We developed a web-based GIS system for the wildlife of Khouzestan Province that provides potential distribution maps and other spatial and nonspatial data on the wildlife of Khouzestan Province and its protected areas. We used MaxEnt and a fuzzy inference system to model distributions of species. Our application was structured using a client/server architecture, and the database design and construction was carried out using PostgreSQL/PostGIS, and GeoServer to serve maps. The mapping interface was developed using OpenLayers; ASP.NET was selected for designing the user interface. We used qualitative-quantitative methods to develop, design, refine, and finalize our system particularly as regards usability. The design approach resulted in a user-friendly interface that allows both specialists and non-specialists to quickly and efficiently run models to estimate potential distributions of species. Our application highlights what can be accomplished with a biodiversity-oriented web application.
显示更多 [+] 显示较少 [-]Effects of Antibiotics on Microbial Communities Responsible for Perchlorate Degradation 全文
2019
Zheng, Xiaoxuan | Jiang, Bo | Lang, Hang | Zhang, Ruirui | Li, Yiqiang | Bian, Yingnan | Guan, Xiangyu
Perchlorate, a pervasive water pollutant, poses a threat to some aquatic environments. Antibiotics, as an emerging contaminant, have increasingly been found in aquatic environments in recent years. As a special co-contaminant, antibiotics modify the composition and function of microbial communities, and the biodegradation rate of perchlorate is changed in the environment. In this study, three typical antibiotics widely found in aquatic ecosystems (lincomycin (LIN), erythromycin (ETM), and sulfadiazine (SDZ)) and two input modes (once and multiple times) were selected to reveal the effects of antibiotics on perchlorate degradation and changes in the microbial community. Additionally, antibiotic resistance gene (ARG) abundance and microbial community composition were analyzed to illustrate the response of bacteria to antibiotic types and input methods by QPCR and high-throughput sequencing. The perchlorate degradation rate was inhibited by three antibiotics (LIN > ETM > SDZ) in this study. LIN and ETM had stronger inhibitory effects on perchlorate degradation, and the abundances of their ARGs increased with increasing antibiotic concentrations. With the continuous culturing and multiple inputs of antibiotics, the percentage of ARGs decreased after crossing a threshold. Additionally, the dominant degradation bacteria were different under pressure from different antibiotics. The type of the antibiotic, the background level of ARGs, and the dissemination of ARGs between bacteria were the main factors influencing the degradation system. The results presented herein will help us understand the modifications of microbial communities that occur in persistent pollutant systems contaminated with antibiotics.
显示更多 [+] 显示较少 [-]Vertical Distribution of Microplastics in Coastal Sediments of Bama Resort, Baluran National Park, Indonesia 全文
2019
Muhammad A. Asadi, Yody A.P. Ritonga, Defri Yona and Asus M.S. Hertika
Microplastic pollution is widely reported in different marine environments from shorelines to seabed of deep seas which pose an emerging threat to entire marine ecosystems. As the world’s secondlargest microplastics polluter, an understanding of the distribution of this type of pollution is important for the measurement of the magnitude of environmental risk. In the present study, the abundance and distribution of microplastics in coastal sediments of Bama Resort, Baluran National Park were measured at depths of 0-10 cm, 10-20 cm, and 20-30 cm. Microplastics characterization was performed using a modified flotation method while a sieve analysis was used to assess the particle size of the sediments. Results showed that there were 484 particles with a total average abundance of 116.41 ± 80.78 particles kg-1 DW. Fibres shared 37.8% of the total microplastics found with overall average of 43.71 ± 36.52 particles kg-1 DW. Overall, Tukey’s multiple comparisons test showed significant differences (P< 0.01) in vertical distribution of microplastics in which 55.46% of particles were found at the depths of 0-10 cm, whereas at the depths of 20-30 cm, the proportion was only 15.95%. There were two types of sediments, sandy gravel and gravelly sand in which the former type of sediments holds higher microplastic particles due to its grain dominance in upper sediments. These results imply that microplastics pollute coastal sediments of Bama Resorts, BNP, and their deposition increase over time as greater microplastics frequencies were observed in upper and more recent sediment.
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