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Prospect of phytoremediation combined with other approaches for remediation of heavy metal-polluted soils Texte intégral
2020
Liu, Shuming | Yang, Bo | Liang, Yunshan | Xiao, Yunhua | Fang, Jun
Accumulation of heavy metals in agricultural soils due to human production activities—mining, fossil fuel combustion, and application of chemical fertilizers/pesticides—results in severe environmental pollution. As the transmission of heavy metals through the food chain and their accumulation pose a serious risk to human health and safety, there has been increasing attention in the investigation of heavy metal pollution and search for effective soil remediation technologies. Here, we summarized and discussed the basic principles, strengths and weaknesses, and limitations of common standalone approaches such as those based on physics, chemistry, and biology, emphasizing their incompatibility with large-scale applications. Moreover, we explained the effects, advantages, and disadvantages of the combinations of common single repair approaches. We highlighted the latest research advances and prospects in phytoremediation-chemical, phytoremediation-microbe, and phytoremediation-genetic engineering combined with remediation approaches by changing metal availability, improving plant tolerance, promoting plant growth, improving phytoextraction and phytostabilization, etc. We then explained the improved safety and applicability of phytoremediation combined with other repair approaches compared to common standalone approaches. Finally, we established a prospective research direction of phytoremediation combined with multi-technology repair strategy.
Afficher plus [+] Moins [-]An effective recycling direction of water-based drilling cuttings and phosphogypsum co-processing in road cushion layer Texte intégral
2020
Li, Bing | Wei, Sha | Zhen, Yi-wen
The technology used in the production and exploration of shale gas creates a new source of clean energy. However, during the processes, large amounts of water-based drilling cuttings (WDC) are generated. Phosphogypsum (PG) is a by-product from the industry of phosphate fertilizer. Approximately, 5 tons of PG are generated for the production of per ton of phosphoric acid. The pile up of WDC and PG lead to severe risks of nearby soil and surface water. This paper paid attention to the recycling of WDC and PG as major raw materials in the preparation of construction cushion layer. In the research, physical properties, microstructure, and environmental pollution of the road cushion layer prepared from WDC and PG were investigated. The results show that the physical properties of compactness and unconfined compressive strength are basic meet the China national standard. The WDC cushion layer mainly constitutes of AFt, C-S-H, and plate-like Ca(OH)₂ around the mineral phases. The leaching test revealed that the contaminants in the layer do not exceed the limits allowed by the “National Overall Discharge Standard of Sewage” (GB 8978-1996). This paper therefore outlines the effects that provide an effective way for the utilization of WDC and PG.
Afficher plus [+] Moins [-]Cardiac toxicity of acrolein exposure in embryonic zebrafish (Danio rerio) Texte intégral
2020
Arman, Sezgi | İşisağ Üçüncü, Sema
Acrolein is a widely distributed pollutant produced from various sources such as industrial waste, organic combustion, and power plant emissions. It is also intentionally released into irrigation canals to control invasive aquatic plants. Zebrafish (Danio rerio) has a good reputation for being an attractive model organism for developmental and toxicological research. In this study, zebrafish embryos were exposed to acrolein to investigate the cardiotoxic effects. The 96-h LC₅₀ (median lethal concentration) value of acrolein was determined as 654.385 μg/L. Then, the embryos were treated with the sublethal experimental concentrations of acrolein (1, 4, 16, 64, and 256 μg/L) for 96 h. Embryos were examined at 48, 72, and 96 h post-fertilization (hpf). Acrolein affected the cardiac morphology and function of the embryos. Sinus venosus-bulbus arteriosus (SV-BA) distance of 64 μg/L and 256 μg/L acrolein groups was elongated compared with the control samples. Immunostaining with MF20 antibody clearly exhibited that the atrium positioned posterior to the ventricle which indicated cardiac looping inhibition. Histological preparations also showed the mispositioning and the lumens of the chambers narrowed. Acrolein-induced increased heart rate was noted in the 4, 16, 64, and 256 μg/L treatment groups. Taken together, these results indicated that acrolein disrupted the heart development and cardiac function in zebrafish, suggesting that its water-borne risks should be considered seriously.
Afficher plus [+] Moins [-]Correlation between urinary chromium level and semen quality in men attending an andrology laboratory Texte intégral
2020
Pokhrel, Gaurab | Shi, Yihao | Wang, Wangcheng | Khatiwada, Shikha Upadhyaya | Sun, Zhongyang | Yan, Jianqiao | Liu, Jihong | Zheng, Dan
Chromium is an essential element that is required for the normal physiology but can be toxic to humans above a certain level. In spite of growing interest in research on chromium exposure to human health consensus about its effect on human, semen quality has not been achieved. The aim of the present study is to evaluate the impact of chromium exposure on semen parameters. A total of 760 males attending andrology laboratory of Tongji Hospital, Wuhan, for routine semen analysis were enrolled and requested to provide semen and urine samples. The urine level of chromium was evaluated using inductively coupled plasma mass spectrometry (ICP-MS), and computer-assisted semen analysis (CASA) was applied to examine semen parameters. Associations between semen parameters and urinary chromium were analyzed by means of multivariate linear regression analysis. Multivariate analysis showed a negative association between the urinary concentrations of chromium and progressive motility (β = − 0.014, p = 0.040) and total motility (β = − 1.077, p = 0.048), while other semen parameters did not show any statistically significant changes. Urinary chromium could influence semen quality parameters and impair male fecundity.
Afficher plus [+] Moins [-]Synergy optimization for the removal of dye and pesticides from drinking water using granular activated carbon particles in a 3D electrochemical reactor Texte intégral
2020
Ghanbarlou, Hosna | Pedersen, Nikoline L. | Nikbakht Fini, Mahdi | Muff, Jens
The combination of adsorption on particulate materials and electrochemical oxidation in 3D electrochemical systems is potentially a very efficient process for the treatment of micropollutants in water. This paper presents results on the use of granular activated carbon as particulate material in the process and treatment of the dye 4-nitrosodimethylaniline and pesticides MCPA (2-methyl-4-chlorophenoxyacetic acid), MCPP (2-methyl-4-chlorophenoxypropionic acid), and the pesticide transformation product BAM (2,6-dichloro-benzamide) in drinking water. 4-nitrosodimethylaniline was used to investigate influential factors as loading of GAC in a batch electrochemical setup and strength of the electric field in a flow cell recirculation batch setup. Results showed that compared to previous studies in distilled water, only additive effects were found in batch setup, and higher electric field strength was needed in the flow cell setup to achieve slight synergy (~ 5%). Reasons were likely due to the indirect oxidation pathways mediated by the anodic chloride oxidation induced by the content of chloride in the drinking water. On MCPA, MCPP and BAM synergies from 28 to 38% were measured in the batch setup, but in the flow cell, results ranged from additive effects (~ 0%) up to 70%. Considering the low price and widespread availability of granular activated carbon, the gain in process removal rates achieved in the combined 3D electrochemical reactor is of interest compared to the individual processes.
Afficher plus [+] Moins [-]Overview of green business practices within the Bangladeshi RMG industry: competitiveness and sustainable development perspective Texte intégral
2020
Sarkar, Apurbo | Qian, Lu | Peau, Anamika Kor
Green business initiatives have become a prime driving force towards sustainable development across the world. The economy of Bangladesh is now on a pick as she has been moving towards nearly hitting the target for becoming a middle-income economy by 2021, and for attaining so, the development of industrial sectors is unavoidable. The booming industrial sectors have been resulting in a massive depletion of natural resources, greenhouse gas erosion, and toxic waste disposal, which further can cause uncontrolled degradation of air, soil, and water. In this highly competitive world, like most other businesses, ready-made garment (RMG) firms are facing tremendous pressure for being more competitive and availing a decisive position towards the reduction of pollution and impacts of ecological footprint. This nation brings a new paradigm of doing business called green business (GB). Principles of green business compact with emerging approaches for producing, marketing, and disposing of the products, which maintain environmental safety and business competitiveness. Green-oriented business strategy can act as a crucial tactic for gaining a competitive advantage over the potential competitors and assess them with a better way to uphold their stand towards attaining sustainable development. Since the modern purchaser is continuously being attracted to green-oriented RMG industries, they want to attain their responsibility to Mother Nature. Especially for the RMG sectors of Bangladesh, environmental concern is highly crucial since it is the most significant economic sectors of this country. The prime objective of this study is to provide an overview of green business strategy associated with the RMG sectors of Bangladesh, which further assist the sectors with competitive advantages. In order to fulfill the prime objectives of the paper, the authors conferred various books, journals, and research papers related to green business and competitiveness within the context of Bangladeshi RMG sectors. Furthermore, the study arranged some casual discussions with industry professionals in corporate social responsibility (CSR), environmental protectionist, sustainable development executives, and ecology-friendly performance officer to provide substantial assistance for focusing on the precise direction of foundation evaluation and synthesis. In contextualization of the intensification of green business strategy and environmental degradation, we proposed a framework to quantify the green business strategy with the view of gain competitive advantages across the RMG sectors in Bangladesh.
Afficher plus [+] Moins [-]Bacopa monnieri (L.) Pennell, a potential plant species for degradation of textile azo dyes Texte intégral
2020
Shanmugam, Laxmi | Ahire, Mahendra | Nikam, Tukaram
The current study highlighted the phytoremediation potential of Bacopa monnieri (L.) Pennell for most commonly used azo dyes which are resistant to degradation. Fourteen azo dyes (reactive: 09; direct: 05) upon treatments up to 40 mg/L were decolorized in the range of 90 to 100% after incubation of 2 weeks in in vitro and hydroponic cultures. No significant alteration in growth of B. monnieri was observed in the presence of dyes R. Magenta MB, R. Navy Blue M2R, Dt. Orange RS, Dt. T Blue GLL, Dt. Sky Blue FF alone, and together in the medium. However, at increasing concentrations (60–100 mg/L), the percent dye decolorization was declined and showed a toxic effect on plant growth. The chlorophyll content declined while membrane damage and osmolyte accumulation were increased in dye treated samples. The biological conversion of produced metabolites was analyzed using FTIR and GC-MS. Our results suggest that the intermediates of Dt. Blue GLL degradation consist L-Proline, N-valeryldecyl ester, 3,5 Di-tert-butyl-4-trimethylsiloxytoulene, and 1,2-benzenedicarboxylic acid, diisooctyl ester. The antioxidative and oxidative enzyme activities in roots and leaves were significantly higher in the presence of dyes over control indicate that these enzymes are involved in degradation of dyes. Percentage seed germination, shoot and root length of seedlings of legume, cereal, and oilseed crop was not affected, suggesting the compatible nature of the produced metabolites. Our results revealed the remarkable ability of Bacopa monnieri for long-term operations that lead to the practical application of phytoremediation in textile industries.
Afficher plus [+] Moins [-]N2 fixation in urbanization area rivers: spatial-temporal variations and influencing factors Texte intégral
2020
Li, Yu | Wang, Dongqi | Chen, Shu | Yu, Zhongjie | Liu, Lijie | Wang, Meng | Chen, Zhenlou
While nitrogen (N₂) fixation is an important process in nitrogen (N) biogeochemical cycling, supplying a significant portion of the N in natural ecosystems, few quantitative constraints exist concerning its contribution to the N enrichment and export from river ecosystems. This study estimates the N₂ fixation rates of urban rivers in the Yangtze Estuary area using acetylene reduction. The results demonstrate that the prominent spatiotemporal variability of river N₂ fixation rates is driven by various environmental factors. River N₂ fixation rates are significantly higher in the summer (90.57 ± 14.60 ngN·L⁻¹·h⁻¹) than in the winter (57.98 ± 15.73 ngN·L⁻¹·h⁻¹). Spatially, rivers draining urban and suburban areas have higher N₂ fixation rates than those draining rural areas. The N₂ fixation rates are positively correlated with the N₂ fixing cyanobacteria density, water temperature, light, and the water phosphorus (P) concentration, but they are negatively correlated with the dissolved N concentration (NH₄⁺-N and NO₃⁻-N). The N₂ fixation rates annually range from 53.20 to 89.24 ngN·L⁻¹·h⁻¹ for all of the sampling rivers, which is equivalent to a depth integrated (0–0.6 m) N input of 0.163–0.274 gN·m⁻²·a⁻¹. The determined annual N input via N₂ fixation is generally higher than that of marine systems, but it is lower than that of eutrophic lakes. This study provides robust evidence that N₂ fixation can supply a substantial portion of the N input to human-impacted river ecosystems, which has not been sufficiently accounted for when determining the N mass balance of riverine ecosystems. A high N₂ fixation rate may increase the ratio of N to P input to river systems, and therefore render P the limiting factor in aquatic eutrophication.
Afficher plus [+] Moins [-]Analysis of spatiotemporal variation in river water quality using clustering techniques: a case study in the Yeongsan River, Republic of Korea Texte intégral
2020
Lee, Kyoung-Hee | Kang, Tae-Woo | Ryu, Hui-Seong | Hwang, Soon-Hong | Kim, Kyunghyun
Herein, cluster analysis was applied to evaluate the spatiotemporal variations in water quality variables of a river. The analysis was performed using the data obtained from 15 monitoring stations during 2007–2018 in the Yeongsan River, Republic of Korea. The spatiotemporal analysis successfully clustered the annual water quality variables temporally into years of poor water quality (2007–2012) and good water quality (2013–2018), and spatially into stations observing bad water quality (midstream) and good water quality (upstream and downstream). For the spatial cluster analysis results before and after a large river engineering project, the water quality was grouped into four clusters according to regional effects and water pollutant sources. The clustering analysis results clearly reflected changes in the water quality along the river due to the project. Overall, this study demonstrates that cluster analysis can be effectively used for evaluating spatiotemporal variations in river water quality.
Afficher plus [+] Moins [-]Quantitative assessment of non-point source pollution load of PN/PP based on RUSLE model: a case study in Beiluo River Basin in China Texte intégral
2020
Hao, Gai-rui | Li, Jia-ke | Li, Shu | Li, Kang-bin | Zhang, Zi-hang | Li, Huai-en
The runoff-sediment relationship in the Yellow River Basin of China is still grim. People pay more and more attention to non-point source (NPS) pollution caused by surface pollutants migrating into the receiving water body with rainfall runoff. The particulate load of pollutants adsorbed in the soil and sediment by erosion and denudation and migration into water is also quite serious. It is necessary to deeply analyze the quantitative relationship between particulate nitrogen and phosphorus (PN/PP) load and soil loss. The soil erosion estimation of different administrative units in the study basin is obtained by the revised universal soil loss equation (RUSLE). The spatial distribution and the variation characteristics at different slopes and different land use of PN/PP load are discussed. An empirical equation of particulate organic load is used to calculate the PN/PP load. The results show that the multi-annual average erosion modulus of the basin is 358.33 t/(km²∙a); the multi-annual average soil erosion reaches 9.62 million tons. The PN/PP load caused by soil loss reaches 11,107.1 t and 7909.3 t, and the export coefficients are 4.13 kg/hm² and 2.94 kg/hm², respectively. Spatial distribution of the PN/PP load is in step with the soil erosion distribution. Soil erosion is prone to occur in the region under the slope of 8 ~ 25°, the NPS load of PN/PP are relatively large, and the average export coefficients of PN/PP are 7.17 kg/hm² and 5.06 kg/hm². With the increase of the slope, the PN/PP load export coefficient increases first and then decreases. Agricultural land (AGRL), forest land (FRST), and pasture (PAST) are the land use types that contribute the most to the PN/PP load and soil erosion, and the average export coefficients of PN/PP are 4.54 kg/hm² and 3.23 kg/hm², respectively. The variability of natural elements, the unevenness and heterogeneity of spatial distribution, and the heavy involvement of human activities will have a conspicuous impact on the soil erosion and NPS pollution processes in the basin. The research on the influence of single factor and combined factors on NPS pollution process can be strengthen and provides scientific theoretical basis for formulating reasonable and efficient water and soil conservation measures and NPS pollution control scheme, so as to achieve effective control and scientific management of environment pollution.
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