细化搜索
结果 3841-3850 的 6,535
Does environmental protection promote economic development? From the perspective of coupling coordination between environmental protection and economic development
2020
Peng, Benhong | Sheng, Xin | Wei, Guo
Environmental protection and economic development seem to be controversial, and there have been opposite views for a long time. Hence, in this article, representative indicators of economy and environment are selected to analyze the external correlation and the internal relationship between environment and economy from the perspective of coupling coordination. The results show that environmental protection may slow down economic growth in the short term. However, their correlation becomes increasingly stronger with higher degree of coupling, and as the result in the long run, environmental protection can gradually improve the infrastructure of economic development, and environmental and economic development will become more closely coordinated in promoting green economic development. It is demonstrated that an effective way to promoting economic development is to promote scientific and technological innovation and cultivate high-end talents and improve regional cooperation, which can reduce the negative effect of environmental protection on economic development. It is also necessary to enhance the positive impact of environmental protection on economic development by transforming the mode of economic development, developing the environmental protection industry, and raising people’s awareness of environmental protection. Thus, the coupling coordination between environment and economy can sustain, with both continuously bolstered.
显示更多 [+] 显示较少 [-]First insight into polybrominated diphenyl ethers in car dust in Turkey: concentrations and human exposure implications
2020
Ozkaleli Akcetin, Merve | Gedik, Kadir | Balcı, Selçuk | Gul, Hatice Kübra | Birgul, Askin | Kurt Karakus, Perihan Binnur
The presence of polybrominated diphenyl ethers (PBDEs) in the car is due to their use as a flame retardant additive in various car components such as dashboard, plastic parts, seat and headliner cushion foams, insulated cables, and electronic circuits. Ingestion of dust inadvertently or dermal contact to dust are significant pathways of human exposure to pollutants including PBDEs. There are no studies documenting presence of car dust associated flame retardants in Turkey. In the current study, a total of 13 PBDEs congeners were investigated in 62 car dust samples collected from Bursa province of Turkey using glass-fiber filters and a vacuum cleaner. Results of the study showed that congener concentrations were within the range of <MDL-40198 ng/g and PBDE-209, major component of commercial deca-BDE, showed the highest concentration among the targeted congeners. Assessment of exposure to analyzed PBDEs via inadvertent dust ingestion and skin contact showed toddlers are exposed to these chemicals approx. 10 times higher compared to adults. Hazard quotient (HQ) values calculated based on total exposure (ingestion + dermal contact) and were < 1 for both adults and toddler indicated that exposure to car dust-associated PBDEs through ingestion and skin contact does not pose any health risks for human in Bursa.
显示更多 [+] 显示较少 [-]Simulation of Methylmercury Content and SRB Methylation in Phragmites australis Soil Under Different Salinity Conditions
2020
Dongmei, Zheng | Shiwei, Zhang | Huanchi, Ma | Huiying, Li
The MeHg content in the reed wetland soil of Liaohe was studied by the indoor-simulated constant temperature culture method. Under different aerobic and anaerobic conditions, the flooding salinity (CK, 0.5%, 1.0%, 1.5%, 2.0%) changes relationship whether SRB plays a leading role in the formation of MeHg. The results showed that under aerobic conditions, the content of MeHg in the surface layer and the bottom layer showed a trend of decreasing first and then increasing with the increase of culture time. Both of them have a lower MeHg content when the flooding salinity is 2.0%. The number of SRB bacteria showed a trend of “upgrading-depleting” with the increase of flooding salinity. Under anaerobic conditions, the MeHg content of surface and bottom soil changed slowly in the early stage of culture (the first 10 days), and the MeHg content increased rapidly after 15 days of culture, and decreased significantly on the 25th day. The number of SRB bacteria showed a trend of “depleting-upgrading” as the flooding salinity increased. Linear fitting showed that there was no obvious linear relationship between the change of MeHg content in soil and the number of SRB bacteria, and other microorganisms may play a role in methylation of mercury. Under anaerobic conditions, MeHg content in surface soil was significantly positively correlated with organic matter (p < 0.01), but negatively correlated with total mercury (p < 0.05). The mercury methylation process is affected by many environmental factors, and the mechanism of mercury methylation in different environments is different.
显示更多 [+] 显示较少 [-]Characterization of Molecular Weight–Based Fluorescent Organic Matter and Its Removal in Combination of Constructed Wetland with Activated Sludge Process
2020
Hidayah, Euis Nurul | Pachwarya, Ram Babu | Cahyonugroho, Okik Hendriyanto | Ramanathan, A. L.
Integrated constructed wetland into activated sludge process has a potential in improving treated wastewater with high organic loading. However, biological activities on those processes will generate microbial by-products from substrate metabolism and cell lysis. The presence of those compounds in effluent of wastewater treatment causes problems in source water. This study combines fluorescence excitation emission matrices (FEEM) with high-performance size exclusion chromatography with fluorescence detector (HPSEC-FLD) to characterize molecular weight–based fluorescent of organic matter and its removal in combination of constructed wetland with activated sludge process. The results show that three components of fluorescence organic: fulvic acid–like (Ex/Em 250/440 nm), SMP-like (Ex/Em 280/350 nm), humic acid–like (Ex/Em 340/420 nm), have been identified in all samples by the FEEM. Further, the HPSEC-FLD, which was set up based on chosen fluorescence wavelength, revealed two different apparent molecular weight (AMW) fractions: high molecular weight (HMW)/biopolymer (50,000 Da) and medium molecular weight (MMW)/humic substance–like (3000–650 Da). Peak-fitting determines that the area of MMW is higher than the area of HMW of all fluorescence organic components, and the area of HMW of fluorescence fulvic acid–like is comparable with the area of SMP-like, and no HMW of humic acid–like detected. Humic acid–like and fulvic acid–like were removed during treatment, while metabolite by-product were released as shown by increasing fluorescence SMP-like and TOC concentration. This method gives new insight to characterize organic matter for assessing effluent of wastewater quality and determining the appropriate water treatment.
显示更多 [+] 显示较少 [-]Distribution, Ecological Risk Assessment, and Source Identification of Heavy Metals in River Sediments from Hai River and Its Tributaries, Tianjin, China
2020
Kang, Mengxin | Tian, Yimei | Zhang, Haiya | Lan, Qian
Heavy metal pollution in river sediments is one of the most serious problems in the aquatic environment. In this study, thirty-two surface sediment and overlying water samples were collected to evaluate the nutrient levels and heavy metal contents (Mo, Cu, Zn, Ni, Cd, Pb, and Cr) in the Hai River and its tributaries, which is the largest river flowing into Bohai Bay. The enrichment degree and geoaccumulation value of the studied metals decreased in the same order of Cd > Cu > Pb > Mo > Ni > Zn > Cr, and the mean contents of Cu and Cd were 2.58 and 2.93 times as high as their background values in Tianjin. Cd contributed over 50% of the ecological risk at the thirty-two sites. Moreover, according to the results of multivariate statistical analyses, Cu and Cd were mainly derived from anthropogenic sources, the quality of overlying water except COD influenced the distribution of heavy metals, and Cd had no correlations with the other heavy metals.
显示更多 [+] 显示较少 [-]Characterization of Tagaran natural clay and its efficiency for removal of cadmium (II) from Sulaymaniyah industrial zone sewage
2020
Aziz, Bakhtyar K. | Shwan, Dler M Salh | Kaufhold, Stephan
The fine fraction of the Tagaran natural clay (TC) from the Kurdistan region of Iraq-Sulaimani was characterized and used to remove Cd ions from industrial swage. Using XRF, XRD, SEM, and FTIR, the dominant clay mineral of the Tagaran clay mineral was identified as saponite, with minor amounts of chlorite. The clay was examined for its efficiency to adsorb and remove (Cd²⁺) in the presence of other heavy metal contaminants from Sulaimani industrial zone sewage by a batch method. The effect of initial pH, equilibrium time, temperature, clay dosage, and Cd²⁺ concentration was studied. Results were evaluated using Langmuir, Freundlich, Temkin, and Redlich-Peterson isotherms. The kinetics could be best fitted to pseudo-second-order reaction kinetic model. In addition, the activation energy and the amount of calculated and experimentally determined heavy metal loads were consistent. The thermodynamic studies showed spontaneous endothermic adsorption. The trioctahedral smectite (saponite) showed a good efficiency for the adsorption of Cd²⁺ from the real sample (up to 100%) which at least partly can be explained by cation exchange. Tagaran clay is a candidate material for the production of an adsorber material for removing Cd²⁺ from aqueous solutions.
显示更多 [+] 显示较少 [-]Effects of climatological parameters on the outbreak spread of COVID-19 in highly affected regions of Spain
2020
Shahzad, Khurram | Shahzad, Umer | Iqbal, Najaf | Shahzad, Farrukh | Fareed, Zeeshan
The coronavirus (COVID-19) pandemic is infecting the human population, killing people, and destroying livelihoods. This research sought to explore the associations of daily average temperature (AT) and air quality (PM₂.₅) with the daily new cases of COVID-19 in the top four regions of Spain (Castilla y Leon, Castilla-La Mancha, Catalonia, and Madrid). To this end, the authors employ Pearson correlation, Spearman correlation, and robust panel regressions to quantify the overall co-movement between temperature, air quality, and daily cases of COVID-19 from 29 February to 17 July 2020. Overall empirical results show that temperature may not be a determinant to induce COVID-19 spread in Spain, while the rising temperature may reduce the virus transmission. However, the correlation and regression findings illustrate that air quality may speed up the transmission rate of COVID-19. Our findings are contrary to the earlier studies, which show a significant impact of temperature in raising the COVID-19 spread. The conclusions of this work can serve as an input to mitigate the rapid spread of COVID-19 in Spain and reform policies accordingly.
显示更多 [+] 显示较少 [-]Mobility and accessibility of Zn, Pb, and As in abandoned mine tailings of northwestern Mexico
2020
Loredo-Portales, René | Bustamante-Arce, Jesús | González-Villa, Héctor Ney | Moreno-Rodríguez, Verónica | Del Rio-Salas, Rafael | Molina-Freaner, Francisco | González Méndez, Blanca | Archundia-Peralta, Denisse
Generation, storage, and management of waste coming from industrial processes are a growing worldwide problem. One of the main contributors is the mining industry, in particular tailings generated by historical mining, which are barely maintained, especially in developing countries. Assessing the impact of a mining site to surrounding soils and ecosystems can be complex, especially when determining mobility and accessibility of the contaminants is required to perform ecological and human health risk assessment. As an effort to obtain information regarding mobility and accessibility of some potentially toxic elements (Zn, Pb, and As) from an historical mining site of northwestern Mexico, the abandoned mine tailings of San Felipe de Jesús in central Sonora and adjacent agricultural soils were investigated. Mobility and accessibility were assessed by means of sequential extraction procedures and using simulated physiological media. Additionally, an assessment of accidental oral intake was calculated considering the bioaccessible fractions. Results show that higher concentrations of contaminants were found in sulfide-rich tailings (Zn = 92,540; Pb = 21,288; As = 19,740 mg kg⁻¹) compared with oxide-rich tailings (Zn = 43,240; Pb = 14,763; As = 13,401 mg kg⁻¹). Concentrations in agricultural soils were on average Zn = 4755, Pb = 2840, and As = 103 mg kg⁻¹. Zinc was mainly recovered from labile fractions in oxide-rich tailings (~ 60%) and in a lower amount from sulfide-rich tailings (~ 30%). Pb and As were mainly associated with residual fractions (80–95%) in both types of tailings. The percentage of mobile fractions (sum of water-soluble, exchangeable, and bound to carbonate fractions) in agricultural soils was as follows: Zn ~ 60%, Pb ~ 15%, and As ~ 70%. Regarding the phytoaccessible fraction, the studied elements in mine tailings and agricultural soil samples exceeded the threshold limits, except for As in agricultural soils. According to data obtained, toxic effects were also calculated. As for daily oral intake for non-carcinogenic effects in adults and children, only Pb and As exceeded reference dose values, especially in children exposed to sulfide-rich tailings and agricultural soils. Regarding carcinogenic effects of Pb and As, most of the samples were above acceptable risk values.
显示更多 [+] 显示较少 [-]Coexistence mechanisms of Tamarix chinensis and Suaeda salsa in the Yellow River Delta, China
2020
Wu, Yanan | Dai, Liyi | Wang, Yu | Xie, Lumeng | Zhao, Shiqiang | Liu, Ying | Zhang, Mingxiang | Zhang, Zhenming
To examine how two dominant species coexist within a tidal wetland in the Yellow River Delta, we studied the spatial distribution patterns and ecological relationships of Tamarix chinensis and Suaeda salsa. We also analyzed the relationship between these two plant species and soil chemical properties. Nine quadrats were established, and aerial photography was carried out in July 2018 in the study area to investigate plants and soil. Results showed that T. chinensis showed an aggregation distribution at scales of 0–10 m, 0–30 m, and 0–50 m from the sea to inland. Unlike T. chinensis, S. salsa showed an aggregation distribution at approximately 0–50 m in the study area, which meant the aggregation distributions of T. chinensis and S. salsa were found at different scales and S. salsa tended to aggregate distribution compared with T. chinensis. Meanwhile, T. chinensis and S. salsa had negative correlations far from the sea at a scale of 0–20 m and at the offshore area at a scale of 0–30 m. However, in the intermediate area, S. salsa and T. chinensis showed a positive correlation at a scale of 0–30 m. In general, the relationship between the two groups tends to be negatively correlated in a small range. Given that the tidal action decreased from the sea to inland, the driving factors of population aggregation gradually changed from tidal flooding to an interspecific relationship. The different characteristics of the different species may also have had an effect. And the aggregation of adult plant species had a beneficial impact on the establishment and growth of seedlings and plants. Furthermore, soil properties comprised complex actions including environmental conditions and ecological processes. The soil chemical properties such as soil salinity and nutrients were also influenced by the species’ canopy.
显示更多 [+] 显示较少 [-]Performance of metal-organic framework as an excellent sorbent for highly efficient and sensitive trace determination of anthracene in water and food samples
2020
Khani, Rouhollah | Ghalibafan, Maryam | Farrokhi, Alireza
Polycyclic aromatic hydrocarbons are a class of highly toxic and unremitting organic pollutants that are widely distributed in the natural environment. In this work, a metal-organic framework (MOF) designated as HKUST-1 [Cu₃(BTC)₂] was synthesized, characterized, and applied as a solid-phase extraction sorbent for the determination of a trace polycyclic aromatic hydrocarbon, anthracene (Ant) as model compound, in various real samples by spectrofluorimetry. The synthesized MOF exhibited large surface areas and high extraction ability, making it excellent candidate as sorbent for enrichment of trace anthracene. The effects of influential parameters on the performance of the dispersive micro-solid-phase extraction (Dμ-SPE) process, such as the initial anthracene concentration, pH, sorbent dosage, and shaking time, were investigated and optimized by the experiment design method. Under the optimized experimental conditions, good linearity in the range of 3–85 ng mL⁻¹ with correlation coefficient 0.997 and good sensitivity with low detection limit 0.5 ng mL⁻¹ for Ant was achieved. The method has been validated in the analysis of real tap water, soft drink, and vegetable juice samples with recoveries in the range of 86.33–103.00% and relative standard deviations in the range of 1.94–3.77%. The as-prepared HKUST-1 was used for at least four times without any obvious decline of extraction capability. The results of this study show the great potential of MOFs as sorbents in Dμ-SPE procedures for the separation and determination of trace Ant in complicated matrices.
显示更多 [+] 显示较少 [-]