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Efficacy study of recycling materials by lemon peels as novel lead adsorbents with comparing of material form effects and possibility of continuous flow experiment Полный текст
2022
Threepanich, Arpassorn | Praipipat, Pornsawai
Lead contamination in the industrial wastewater is a major concern because of human health effects, so wastewater treatment is required before uses. Adsorption is an effective method with a reasonable cost, and natural wastes are an interesting choice as low-cost adsorbent. Lemon peels were chosen with their proper chemical properties for lead removal. This study is aimed at synthesizing lemon peel adsorbents; analyzing adsorbent characterizations; investigating affecting factors on dose, contact time, pH, and concentration; examining adsorption isotherms and kinetics; and exploring desorption experiments and fixed-bed column experiments. This study was successful synthesized adsorbents of lemon peel powder (LP) and beads (LPB) and was characterized through XRD, FESEM-FIB, EDS, BET, and FTIR. The optimum conditions of LP and LPB of 50 mg L⁻¹ lead concentration were 4 g, 6 h, and pH 5 and 3 g, 5 h, and pH 5, respectively. Both adsorbents were corresponded to Freundlich and pseudo-second-order kinetic model. Fixed-bed column experiments which represented LPB had high lead removal efficiency with the adsorption capacity of 1.67 mg g⁻¹, and it was also a good reusability more than 2 cycles. Therefore, LPB is a potential adsorbent to possibly apply for wastewater treatment.
Показать больше [+] Меньше [-]An impact of climate change and groundwater salinity on shadow price of water, farmers’ revenue, and socioeconomic and environmental indicators in district Kohat-Pakistan Полный текст
2022
Khan, Arshad Ahmad | Khan, Sufyan Ullah | Ali, Muhammad Abu Sufyan | Javed, Tehseen | Khan, Aftab | Luo, Jianchao
Globally, agricultural productivity is adversely impacted due to climatic changes as the temperatures rises and precipitation decreases, and especially in Pakistan, which ultimately enhanced groundwater salinity and harmed water quality in the country. However, the impacts of groundwater salinity and climate change on farmers’ revenue have not been fully understood in Pakistan. Therefore, the focus of current research is the assessment of shadow price of water, farmers’ revenue, and socioeconomic and environmental indicators affected by variations in groundwater salinity, precipitation, and temperature. The estimation of crop yield sensitivity to groundwater salinity, precipitation, and temperature and their prediction for 2030, 2040, and 2050 time periods was accomplished through the technique of General Maximum Entropy and Response-Yield function. Moreover, the assessment of groundwater quality and climate variable impacts on socioeconomic and environmental indicators was obtained through Target Motad-PMP model. In the end, the most suitable climate change scenario in the study area was established by applying a multi-criteria decision-making method. The results revealed that groundwater salinity and temperature expressed a significantly increasing trend with the Z values of 5.82 and 2.15, respectively. While the precipitation depicted a significantly decreasing trend (Z value = −3.37). The negative impact of climatic changes and groundwater salinity was revealed for revenue risk and shadow prices of water. The most negative impact on income risk and shadow prices is during 2050 horizon with a decrease by 11.4 and 19.4% respectively. The environmental index is the most important with a priority of 43.4% compared to the socio-economic indicators. The sub-index water use is also significant in the study area with a priority of 28.1%. A2 is the most appropriate climate scenario conferring to the TOPSIS ranking method. Therefore, the A2 scenario should be taken into account for the policy of adaptation to the climate change wonder in district Kohat.
Показать больше [+] Меньше [-]A green, environment-friendly, high-consolidation-strength composite dust suppressant derived from xanthan gum Полный текст
2022
Li, Miaomiao | Zhao, Yanyun | Bian, Susu | Qiao, Jian | Hu, Xiangming | Yu, Shijian
To solve issues of low consolidation strength, poor dust suppression effect, and secondary pollution of the current coal dust suppressors, a greener and higher-consolidation-strength composite dust suppressor was synthesized by the radical polymerization of xanthan gum (XG) as the graft substrate, methyl acrylate (MA), and vinyl acetate (VAc) as the graft monomers. Taking compressive strength as the main optimization index and viscosity and surface tension as the secondary indices, the optimum ratio of MA:VAc was 3:5 and the optimum solid content was 2%. Experiments reveal that the prepared dust suppressant can naturally infiltrate into coal to form a hard solidified layer. At a wind speed of 10 m/s, the solidified layer still maintained structural integrity, indicating that the dust suppressant exhibits a good dust fixation effect. The dust suppressant can not only maintain relatively stable performance for a period of time but also degrade naturally. Furthermore, molecular dynamics simulation reveals not only the interaction mechanism between coal molecules and the dust suppressor but also the wetting mechanism of the dust suppressor. Experimental and simulation results reveal that as a multifunctional dust suppressor with excellent performance, the as-prepared dust suppressor demonstrates the immense potential for the control of coal dust. Graphical abstract
Показать больше [+] Меньше [-]Potential distribution of the extremely endangered species Ostrya rehderiana (Betulaceae) in China under future climate change Полный текст
2022
Tang, Shuang-Li | Song, Yao-Bin | Zeng, Bo | Dong, Ming
Global climate change is a major threat to biodiversity, which may increase the extinction risk of rare species, particularly those like Ostrya rehderiana Chun (Betulaceae) with very few remaining extant wild individuals. We aimed to estimate the potential distribution of O. rehderiana under climate change and to analyze possible relevant climatic factors. Maximum entropy (Maxent) was employed to model the potential distribution of O. rehderiana under present and future climate scenarios. Suitable habitat areas in different periods and the main contributing climate factors were identified using species distribution models. The minimum temperature in winter and precipitation seasonality were the principal climatic factors influencing the establishment of O. rehderiana. The proportion of high potential distribution area in China was 3.91% and would further shrink significantly under changing climate, especially reduce by 97% under high radiative forcing. The extinction risk of O. rehderiana would still be extraordinarily high under future climate scenarios. The Tianmu and Luoxiao Mountains would be the only potential refugia for O. rehderiana in the future. Special conservation efforts are urgently required to rescue extremely endangered species as O. rehderiana. We propose priorities for the conservation region and suggestions for conservation management strategies.
Показать больше [+] Меньше [-]The occurrence of perfluoroalkyl substances (PFAS) in drinking water in the Czech Republic: a pilot study Полный текст
2022
Jurikova, Martina | Dvorakova, Darina | Pulkrabova, Jana
Drinking water is one of the main contributors to overall human exposure to per- and polyfluoroalkyl substances (PFAS), a broad group of environmental contaminants with arising concerns on the impact on human health; therefore, it is necessary to monitor its quality. Here, we present a solid-phase extraction-based method to determine 22 PFAS in water, using 100 mL of the sample. The instrumental analysis employing an ultra-high-performance liquid chromatography coupled with tandem mass spectrometry achieved low limits of quantification (0.025–0.25 ng/L). The validated method (recoveries 70–120% and repeatabilities ≤ 20% at tested concentrations (0.05, 0.1 and 0.5 ng/L)) was applied to 67 tap water and 31 bottled water samples collected in the Czech Republic. The most abundant compounds were perfluorononanoic acid (88% positives; 0.034–13.3 ng/L) and perfluoroheptanoic acid (23% positives; 0.035–0.106 ng/L), respectively. ∑PFAS in positive samples ranged from 0.029 to 300 ng/L (99% positives, median 2.34 ng/L) in tap water data and 0.033 to 4.48 ng/L (32% positives, median 0.097 ng/L) in bottled water samples. Current-use fluoroalkyl ethers, dodecafluoro-3H-4,8-dioxanonanoate and 11-chloroeicosafluoro-3-oxaundecane-1-sulfonate, were occasionally detected in tap. Based on the median data, PFAS intake by an adult from a tap or bottled water represented units of % of the tolerable weekly intake set by the European Food Safety Authority and therefore did not represent a severe risk. The described method and obtained first data on PFAS in the Czech drinking water provided a solid basis for an ongoing national study on the presence of PFAS in tap water.
Показать больше [+] Меньше [-]Large spatio-temporal variations of size-resolved particulate matter and volatile organic compounds in urban area with heavy traffic Полный текст
2022
Phuc, Nguyen Hong | Oanh, Nguyen Thi Kim
A monitoring campaign, the first of this kind for a heavy traffic urban area of Vietnam, was conducted which generated nearly 200 daily filter samples of PM₂.₅, PM₁₀, and black carbon (BC), 1300 online hourly PMx (PM₁₀, PM₂.₅, and PM₁), 900 hourly/bi-hourly BTEX data, 700 h of traffic counts, and online meteorology records. PMx and BTEX levels show large horizontal gradients across this small urban area of 300 m width suggesting that the pollution data should be generated with sufficient spatial resolutions for assessment of the exposure and health effects. This paper focuses on analyzing PMx with reference to the previously published BTEX to provide a more complete picture of the traffic-related pollution in the area. Spatio-temporal variations of pollutants are analyzed in relation to traffic flows and fleet compositions, weekday-weekend effects, local and regional meteorology. PM₁₀ and BTEX levels had larger variations between the sites indicating their stronger associations with the traffic activities than the finer particles. Twenty-four-hour (24 h) PM₂.₅ levels ranged between 19 and 191 µg/m³ with high PM₁/PM₂.₅ ratios of above 0.8 at ambient site (AA) and above 0.7 at roadsides. Multivariate relationship analysis (PCA) for the bi-hourly datasets of meteorology, traffic flows, and pollutant levels indicated overwhelming influence of on-road traffic fleet compositions on the roadside pollutants levels. At AA, PCA results showed a complex interaction between local emissions, meteorological conditions, and regional/long-range transport. Higher pollution levels were associated with the airmass types having the continental origin and pathways.
Показать больше [+] Меньше [-]Heavy Metal Pollution in the Surface Sediments from Cage Aquaculture Farms in the Volta Basin of Ghana: Source Identification and Ecological Risk Assessment Полный текст
2022
Magna, Emmanuel Kaboja | Koranteng, Samuel Senyo | Donkor, Augustine | Gordon, Christopher
While aquaculture is quickly expanding throughout the Volta Basin and creating several economic benefits, environmental reservations about the cage fish farming industry’s externalities have risen. The pollution, potential sources, ecological risk, and concentrations of heavy metals (Cd, Pb, Ni, Cr, Mn, Fe, Zn, Cr, and As) in sediments were investigated in four cage aquaculture farms (fish farms A, B, C, and D) and control using an atomic absorption spectrometer. The metal concentrations of Zn (0.01 ± 0.001 mg/kg (dw)) and Mn (25.22 ± 1.509 mg/kg (dw)) were the lowest and highest in control and fish farm A, respectively. Heavy metal loads in the farms were in the order: fish farm C (50.14 mg/kg dw) > fish farm D (47.20 mg/kg dw) > fish farm A (40.98 mg/kg dw) > fish farm B (38.61 mg/kg dw) > control (8.44 mg/kg dw). Except for Pb in fish farms C and D, all other heavy metals found in the sediment were below the US EPA and WHO maximum residue levels. Pollution assessment using various indices suggested negligible anthropogenic disturbances except for Mn (moderate enrichment in farms A, B and the control) and Pb (severe enrichment in farms C and D). Ecological risk analysis suggested no potential risk to the benthos in the sediment. PCA revealed that metals were primarily from lithogenic and anthropogenic sources. Other physical, biological, and chemical aspects will need to be investigated in the future to obtain a greater understanding of the environmental impact of cage fish farming in the Basin.
Показать больше [+] Меньше [-]Does educated labor force is managing the green economy in BRCS? Fresh evidence from NARDL-PMG approach Полный текст
2022
Naseer, Saira | Song, Huaming | Supat Chupradit, | Maqbool, Adnan | Hashim, Nik Alif Amri Nik | Vu, Hieu Minh
It is observed that an educated labor force can increase the absorption capacity of the economy and improve the effectiveness of green technologies that lead to a reduction in potential CO2 emissions. The study investigates whether an educated labor force contributes to the management of the green economy or not in BRCS economies. Panel ARDL-PMG and NARDL-PMG approaches have been employed for empirical analysis for data ranging from 1995 to 2019. According to the ARDL-PMG results, a highly educated labor force contributes to alleviating CO2 emissions in the long run. In contrast, the findings of NARDL-PMG infer that positive component of a highly educated labor force has a significant negative impact on CO2 emissions, while negative component of a highly educated labor force has a positive impact on CO2 emissions in the long run. The study suggests that BRCS countries’ policymakers should promote education and training for the labor force to maintain a reduction in CO2 emissions.
Показать больше [+] Меньше [-]Modeling impacts of mining activity-induced landscape change on local climate Полный текст
2022
Bi, Hongru | Chen, Wei | Li, Jun | Guo, Junting | She, Changchao
As a major energy source, coal has been mined on an increasingly larger scale as the social economy has continuously developed, resulting in drastic land type changes. These changes in turn cause changes in the local climate and affect the local ecological environment. Therefore, for coal cities, mining activities are an important factor influencing the local climate, and clarifying the impact of mining activities on the ecological environment is important for guiding regional development. In this paper, the impact of land use/cover changes (LUCCs) on local temperature in the spring and summer seasons from 1980 to 2018 was simulated using the Weather Research and Forecasting (WRF) model with Xilinhot city as the study area, and the regional distribution of local surface energy was analyzed in conjunction with the ground-air energy transfer process. The results show that the grassland area in Xilinhot remained above 85% from 1980 to 2018, so mining activities had a small impact on the average temperature of the whole region. However, in the mining area, the warming effect caused by mining activities was more obvious, with an average temperature increase of 0.822 K. Among other land transformation types, the conversion to water bodies had a very obvious cooling effect, lowering the temperature by an average of 2.405 K. By comparing the latent heat flux (LH), sensible heat flux (SH), and ground heat flux (GRD) under different land use types, it was found that in 2018, the LH decreased by 0.487 W/m², the SH decreased by 0.616 W/m², and the GRD decreased by 0.753 W/m². The conversion to built-up urban land caused a significant decrease in the LH in the corresponding area, allowing more energy to be used to increase SH values, which resulted in significantly higher urban temperatures than in other areas.
Показать больше [+] Меньше [-]Regulation of Paraquat for wheat crop contamination Полный текст
2022
Guptā, Sandhyā | Garg, Navneet Kumar | Shekhawat, Kapila
Paraquat is a highly toxic and persistent pesticide in soil but is still used for wheat crops in many countries. Paraquat can pose potential health hazards if it is translocated from soil into wheat grains, but no study is available for its possible translocation causing wheat grain contamination. The present study aimed at finding out Paraquat residue in wheat grains under field conditions for two crop seasons to explore the sustainability of this pesticide. The experiments were conducted scientifically under field conditions at agricultural fields Pusa, Delhi, India. The soil texture was classified as sandy loam. Paraquat dichloride 24% SL (herbicide) was applied on five fields except for control field. Paraquat in wheat grains was analyzed using HPLC equipped with a photodiode array (PDA) detector. The method of analysis was validated for the pesticide residue recovery. The results showed that there was an alarming concentration of Paraquat in wheat grains ranging between 21.6 and 49.02 mg kg⁻¹ against maximum residue level of 0.1 mg kg⁻¹. Paraquat was also found in control crop (3.1 mg kg⁻¹) due to background residue in soil even when no Paraquat was applied. Furthermore, wheat flour samples from market also gave alarming Paraquat residue (20.39, 25.88, and 27.68 mg kg⁻¹). Paraquat residue was primarily dependent on % clay in field soils. More the % clay lesser was Paraquat residue in wheat grain. Thus, Paraquat was translocated from soil into wheat grains and resulted in worrying concentration of Paraquat residue in wheat grains. Consequently, use of Paraquat for wheat crops needs to be regulated as it contaminated the soil and resulted in the wheat grain contamination posing severe health hazards for humans.
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