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Результаты 2761-2770 из 4,896
Pollution, demographic, and public willingness to participate in environment protection in China—a study based on micro-survey data
2019
Wang, Xinxin | Fan, Pengpeng | Wu, Zheng | Liang, Qiao
Previous study found out that Chinese household have a higher awareness of environmental protection but less positive initiative to protect the environment. With the increasing Chinese income, higher education, and changing environment state, public awareness and behavior on environment protection are changing. This paper tries to find out the current public willingness to participate in environment protection, by using the latest data from China Household Finance Survey (CHFS) which is investigated in 2017 that covered 31 provinces with a sample of more than 40 thousand households. Besides, logit regression model is adopted to find out the impact of pollution and household demographic on environment protection behavior. The results show that around 71.6% of surveyed households have willingness to pay for the environment protection. Rural residents and higher educated individuals are more likely to participate in environment protection. However, things are different if they face different degrees of pollution. Results can be explained with China’s current economic situation and would have some implications for future study on China’s public willingness to pay for the environment.
Показать больше [+] Меньше [-]Preparation of chitosan/Co-Fe-layered double hydroxides and its performance for removing 2,4-dichlorophenol
2019
Yang, Bo | Liu, Jun | Liu, Zhiguo | Wang, Yacheng | Cai, Jiaming | Peng, Lingjie
Chitosan/Co-Fe-layered double hydroxides (CS/LDHs) were prepared by coprecipitation method, which is a kind of composite material with excellent properties. The structure of CS/LDHs was characterized by SEM, FTIR, and XRD, which proved that chitosan (CS) was successfully induced into hydrotalcite and CS/LDHs still possess the structural characteristics of hydrotalcite. The adsorption of 2,4-dichlorophenol (2,4-DCP) was studied with CS/LDHs and LDHs as adsorbent separately. The activity of immobilized laccase (L-CS/LDHs) with CS/LDHs as carrier is significantly better than that of the one (L-LDHs) using LDHs as carrier. Under the optimum conditions (pH = 6, 55 °C, 48 h), L-CS/LDHs exhibited better removal performance for 2,4-DCP (81.53%, 100 mg/L) than LDHs (63.55%); the removal of 2,4-DCP by L-CS/LDHs is excellent, exceeding 97% as its initial concentration below 60 mg/L. It includes the catalytic action of laccase and dechlorination of Fe³⁺ and Co²⁺, and the adsorption can be ignored under the optimal conditions. After 5 cycles, it maintained 67% (L-CS/LDHs) and 54% (L-LDHs) of the original removal.
Показать больше [+] Меньше [-]Sensitivity of physiological and biochemical endpoints in early ontogenetic stages of crops under diclofenac and paracetamol treatments
2019
Zezulka, Štěpán | Kummerová, Marie | Babula, Petr | Hájková, Markéta | Oravec, Michal
Early stages of ontogenesis determining subsequent growth, development, and productivity of crops can be affected by wastewater and sludge contaminated with pharmaceuticals. Diclofenac (DCF) and paracetamol (PCT; both 0.0001 to 10 mg/L) did not affect seed germination and primary root length of onion, lettuce, pea, and tomato. Conversely, 20-day-old pea and maize plants exhibited decrease in biomass production, leaf area (by approx. 40% in pea and 70% in maize under 10 mg/L DCF), or content of photosynthetic pigments (by 10% and 60% under 10 mg/L PCT). Quantum yields of photosystem II were reduced only in maize (FV/FM and ΦII by more than 40% under 10 mg/L of both pharmaceuticals). Contents of H₂O₂ and superoxide increased in roots of both species (more than four times under 10 mg/L PCT in pea). Activities of antioxidant enzymes were elevated in pea under DCF treatments, but decreased in maize under both pharmaceuticals. Oxidative injury of root cells expressed as lowered oxidoreductase activity (MTT assay, by 40% in pea and 80% in maize) and increase in malondialdehyde content (by 60% and 100%) together with the membrane integrity disruption (higher Evans Blue accumulation, by 100% in pea and 300% in maize) confirmed higher sensitivity of maize as a C4 monocot plant to both pharmaceuticals.
Показать больше [+] Меньше [-]Organotin compounds in touristic marinas of the northern Adriatic Sea: occurrence, speciation and potential recycling at the sediment-water interface
2019
Formalewicz, Malgorzata M. | Rampazzo, Federico | Noventa, Seta | Gion, Claudia | Petranich, Elisa | Crosera, Matteo | Covelli, Stefano | Faganeli, Jadran | Berto, Daniela
Butyltin compound (BTC) contamination was evaluated in two north Adriatic marinas, San Rocco (Italy) and Lucija (Slovenia). BTC sedimentary concentrations (121 ± 46 and 352 ± 30 ng Sn g⁻¹ in San Rocco and Lucija, respectively) evidenced the past use of antifouling paints, confirmed by the reduced tributyltin content (~ 46%) with respect to the sum of BTC. Elemental and organic carbon isotopic (δ¹³C) analyses of bulk sediments and its lipid and humic substances were performed in order to evaluate their role in BTC partitioning and preservation. The δ¹³C of sedimentary bulk and refractory organic matter suggested that diagenetic processes could play a role in the preservation or release of pollutants. No contamination was found in water collected from the benthic chamber and thus, fluxes at the sediment-water interface were not assessed, except for MBT efflux at Lucija (28.9 ng Sn m⁻² day⁻¹). Nevertheless, BTC concentrations in porewaters (up to 75 ng Sn l⁻¹) and rather low sediment-porewater partitioning coefficients (Kd) with respect to the data reported in the literature would suggest a potential risk of the reintroduction of BTC into the water column at both sites: at Lucija, sedimentary contamination is high despite the greater Log Kd, whilst at San Rocco, the low BTC concentration is associated with a reduced sediment affinity.
Показать больше [+] Меньше [-]Development of magnetic porous coordination polymer adsorbent for the removal and preconcentration of Pb(II) from environmental water samples
2019
Al’Abri, Aisha Mohammed | Mohamad, Sharifah | Abdul Halim, Siti Nadiah | Abu Bakar, Nor Kartini
A novel porous coordination polymer adsorbent (BTCA-P-Cu-CP) based on a piperazine(P) as a ligand and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a linker was synthesized and magnetized to form magnetic porous coordination polymer (BTCA-P-Cu-MCP). Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), field emission scanning electron microscope(FESEM), energy-dispersive X-ray spectroscopy(EDS), CHN, and Brunauer–Emmett–Teller(BET) analysis were used to characterize the synthesized adsorbent. BTCA-P-Cu-MCP was used for removal and preconcentration of Pb(II) ions from environmental water samples prior to flame atomic absorption spectrometry(FAAS) analysis. The maximum adsorption capacity of BTCA-P-Cu-MCP was 582 mg g⁻¹. Adsorption isotherm, kinetic, and thermodynamic parameters were investigated for Pb(II) ions adsorption. Magnetic solid phase extraction (MSPE) method was used for preconcentration of Pb(II) ions and the parameters influencing the preconcentration process have been examined. The linearity range of proposed method was 0.1–100 μg L⁻¹ with a preconcentration factor of 100. The limits of detection and limits of quantification for lead were 0.03 μg L⁻¹ and 0.11 μg L⁻¹, respectively. The intra-day (n = 7) and inter-day (n = 3) relative standard deviations (RSDs) were 1.54 and 3.43% respectively. The recoveries from 94.75 ± 4 to 100.93 ± 1.9% were obtained for rapid extraction of trace levels of Pb(II) ions in different water samples. The results showed that the BTCA-P-Cu-MCP was steady and effective adsorbent for the decontamination and preconcentration of lead ions from the aqueous environment.
Показать больше [+] Меньше [-]The impact and mechanism of quaternary ammonium compounds on the transmission of antibiotic resistance genes
2019
Han, Yue | Zhou, Zhen-Chao | Zhu, Lin | Wei, Yuan-Yuan | Feng, Wan-Qiu | Xu, Lan | Liu, Yang | Lin, Ze-Jun | Shuai, Xin-Yi | Zhang, Zhi-Jian | Chen, Hong
The emergence of antibiotic resistance genes (ARGs) in microbes can be largely attributed to the abuse and misuse of antibiotics and biocides. Quaternary ammonium compounds (QACs) have been used worldwide as common disinfectants and detergents; however, their potential impact on the spread and diffusion of ARGs is still unknown. In this study, we detected the QAC resistance gene (qacEΔ1), the 1 integron gene (intI1), and 12 ARGs (sul1, sul2, cfr, cml, fexA, tetA, tetG, tetQ, tetX, ermB, blaTEM, and dfrA1) in 48 water samples from three watersheds by quantitative PCR (qPCR). We investigated the evolution of bacterial antibiotic resistance under QAC and antibiotic environmental pressures by long-term continuous culture. In addition, five QACs were selected to investigate the effect of QAC on the efficiency of conjugation transfer. The changes in bacterial cell membrane and production of reactive oxygen species (ROS) were detected by flow cytometry, revealing the mechanism by which QAC affects the spread of antibiotic resistance. Our results showed that the QAC resistance gene was ubiquitous in watersheds and it had significant correlation with intI1 and seven ARGs (r = 0.999, p < 0.01). QACs could increase the resistance of bacteria to multiple antibiotics. Furthermore, all five QACs promoted the conjugation transfer of the RP4 plasmid; the optimal concentration of QACs was about 10⁻¹–10⁻² mg/L and their transfer efficiencies were between 1.33 × 10⁻⁶ and 8.87 × 10⁻⁵. QACs enhanced membrane permeability of bacterial cells and stimulated bacteria to produce ROS, which potentially promoted the transfer of plasmids between bacteria. In conclusion, this study demonstrated that QACs may facilitate the evolution and gene transfer of antibiotic resistance gene among microbiome.
Показать больше [+] Меньше [-]Evaluation of mercury phytoavailability in Oxisols
2019
Lima, Francielle R. D. | Engelhardt, Mateus M. | Vasques, Isabela C. F. | Martins, Gabriel C. | Cândido, Geraldo S. | Pereira, Polyana | Reis, Rayner H. C. L. | Silva, Aline O. | Guilherme, Luiz Roberto G. | Marques, João José
Mercury is a metal which is potentially toxic for the environment. Many factors control its retention in the soil, such as cation exchange capacity, pH, clay content, organic matter, and redox potential. It is important to know the phytotoxic effects of soil Hg to prevent environmental contamination and its entry into the food chain. Several analytical methods are used to measure metal phytoavailability in soils, but none has been reported for Hg in Oxisols, the most common soil class in Brazil and a very important soil class throughout the tropics. The aim of this study was to select the chemical extractor that best correlated the Hg levels in plants and the Oxisols. The soils used were classified as Dystrophic Red-Yellow Oxisol (LVAd) and Dystroferric Red Oxisol (LVdf), which were collected in the 0–0.2-m soil layer. The species selected for cultivation were a monocotyledon, oat (Avena sativa L. cv. São Carlos) and a eudicotyledon, common bean (Phaseolus vulgaris L. cv. Madrepérola). Each test plot was composed of a 500 cm³ pot filled with soil samples contaminated with HgCl₂. Treatments were arranged in a completely randomized design, with four replications. The experiment was conducted for 30 days. Mercury contents were separately extracted with the following extractors: USEPA 3051A, Mehlich-1, Mehlich-3, DTPA, and water. Mercury was determined by hydride generation atomic absorption spectroscopy. The extracted contents were correlated with the contents in the tissues of the plants’ aerial part by the Pearson correlation. Although it is not considered a standard procedure to evaluate metal phytoavailable contents, the method that presented the best correlations between soil Hg and plant Hg was USEPA 3051A (r = 0.75*). As expected, the worst correlation was with water (r = 0.57* for common bean and r = 0,05ⁿˢ for oat).
Показать больше [+] Меньше [-]Evaluating polar pesticide pollution with a combined approach: a survey of agricultural practices and POCIS passive samplers in a Tunisian lagoon watershed
2019
Mhadhbi, Takoua | Pringault, Olivier | Nouri, Habiba | Spinelli, Sylvie | Beyrem, Hamouda | Gonzalez, Catherine
A study of pesticides in the Bizerte lagoon watershed on the Mediterranean coast of Tunisia showed that herbicides and fungicides are the most commonly used compounds. A survey was made of selected farmers. Pesticide contamination was monitored in the water column and sediments at four selected sampling sites (lagoon (A) and in three oueds—Chegui (B), Garaa (C), and Tinja (D)). Polar organic chemical integrative samplers (POCIS) were used to assess pesticide contamination. Thirty-two pesticides were investigated; the total concentration of active ingredients ranged from 35.9 ng L⁻¹ in Tinja oued to 1246 ng L⁻¹ in Chegui oued. In the lagoon, the total concentration of pesticides was 67.7 ng L⁻¹. In the sediments, the highest concentration was measured in Chegui oued in the spring (31 ng g⁻¹ dw). The main compounds found in the analyzed sediments were prosulfocarb and tebuconazole molecules.
Показать больше [+] Меньше [-]The adsorption behavior of multiple contaminants like heavy metal ions and p-nitrophenol on organic-modified montmorillonite
2019
Liu, Yawei | Luan, Jingde | Zhang, Chengyu | Ke, Xin | Zhang, Haijun
Stearyl trimethyl ammonium chloride (STAC) and ethylenediamine (En) were successfully implanted into montmorillonite (MMt) interlayer to fabricate the novel adsorbent STAC-En-MMt for the simultaneous adsorption of Cu²⁺, Zn²⁺, and p-nitrophenol (PNP). X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analyzer, zeta potential analyzer, inductively coupled plasma mass spectrometry, and UV–visible spectrophotometer were used to investigate the microstructure characteristics of STAC-En-MMt and their adsorption capacity of target contaminants. Four factors such as pH, the molar ratio between En and STAC (REₙ/STAC), the adsorption time (ATᵢₘₑ), and the adsorption temperature (ATₑₘₚ) were selected to investigate the adsorption capacities of Cu²⁺, Zn²⁺, and PNP onto STAC-En-MMt in ternary solution. The results indicated that the total simultaneous adsorption of Cu²⁺, Zn²⁺, and PNP onto STAC-En-MMt adsorbent with REₙ/STAC = 0.75 reached up to 260.27 mmol·kg⁻¹ under the condition of pH = 6, ATₑₘₚ = 40 °C, and ATᵢₘₑ = 60 min. After three regenerations, there was still a good performance in the adsorption of STAC-En-MMt. The Langmuir adsorption isotherm indicated that the adsorption of heavy metals and PNP onto adsorbents were single-layer surface adsorption. Nonlinear adsorption kinetics simulation indicated that chemical adsorption occupied a predominant position in Cu²⁺ and Zn²⁺ adsorption, while PNP adsorption depended on physical adsorption. Compared with Zn²⁺, Cu²⁺ had higher affinity for the adsorption sites on STAC-En-MMt. However, the pore blocking caused by the Cu²⁺ and Zn²⁺ adsorption had a remarkably adverse effect on PNP adsorption.
Показать больше [+] Меньше [-]Metal distribution in sediments of a drinking water reservoir: influence of reservoir morphometry and hydrodynamics
2019
Zhu, Lin | Wang, Tianxiang | Liu, Jianwei | Xu, Shiguo | Chen, Xiaoqiang | Jiang, Xin
Metal(loid)s in the reservoir sediment tend to be released into the water column when encountering disturbances and thus pose threats to the aquatic system. In this study, sediment and pore water samples collected from eight cross sections in the Biliu River Reservoir (Dalian, China) were analyzed to determine the spatial distributions of six metal(loid)s and their associations with reservoir morphometry and hydrodynamics. The results show that total metal concentrations of the sediments are higher at the sites with greater water depths and are influenced by the reservoir morphometry. Mn is of great concern with respect to its increasing total concentration from the upstream sites to the dam sites. According to the improved BCR sequential extraction procedure, the acid-soluble fraction of Mn increases along the thalweg to the dam, implying the soluble Mn²⁺ in the upstream hypolimnion, and sediment is possible to be transported longitudinally by water currents. For Fe, Mn, Pb, Cu, and Zn, the reducible fraction accounts for more than 15% of the total metal concentration, which suggests that Fe–Mn (hydr)oxides could be important in scavenging these metals. High Mn concentrations in pore waters close to the dam, with an average value of more than 40 mg/L, give rise to significant Mn diffusive flux up to 296.1 mg/m²/day.
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