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Bioaccumulation of potentially toxic elements in three mangrove species and human health risk due to their ethnobotanical uses 全文
2021
Chowdhury, Abhiroop | Naz, Aliya | Maiti, Subodh Kumar
The aim of this study was to assess probabilistic human health risk due to ethnobotanical usage of Avicennia officinalis, Porteresia coarctata and Acanthus ilicifolius. The study was conducted at the tannery outfall near Sundarban (Ramsar wetland, India) mangrove ecosystem affected by potentially toxic elements (Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn). Total metal concentrations (mg kg⁻¹) were considerably higher in the polluted rhizosphere namely, Cd (1.05–1.97), Cu (36.3–38.6), Cr (144–184), Hg (0.04–0.19), Mn (163–184), Ni (37.7–46.4), Pb (20–36.6), and Zn (97–104). Ecological risk index indicated low to moderate ecological risk in this site, whereas the ecological risk factor showed high potential ecological risk due to Cd pollution. BCR Sequential extraction of metals showed more exchangeable fraction of Cd (47–55%), Cr (9–13%), Hg (11–13%), and Pb (11–15%), at the polluted site. Mercury, though present in trace amount in sediment, showed the highest bioaccumulation in all the three plants. Among the toxic trio, Hg showed the highest bioaccumulation in A. officinalis, Cd in P. coarctata but Pb has the lowest bioaccumulation potential in all the three species. Occasional fruit consumption of A. officinalis and dermal application of leaf, bark of A. officinalis (antimicrobial), A. ilicifolius (anti-inflammatory, pain reliever when applied on wounds) indicated negligible human health risk. However, long-term consumption of P. coarctata (wild rice variety) seeds posed health risk (THQ>1) both in adults and children age groups. This study concludes that nature of ethnobotanical use and metal contamination levels of the mangrove rhizosphere can impact human health. The transfer process of potentially toxic elements from rhizosphere to plants to human body should be considered while planing pollution mitigation measures. Graphical Abstract
显示更多 [+] 显示较少 [-]Human health risk assessment of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) pesticide residues in fruits and vegetables in Nigeria 全文
2021
Odewale, Gideon Oluwasogo | Sosan, Mosudi Babatunde | Oyekunle, John Adekunle Oyedele | Adeleye, Adeoluwa Oluwaseyi
The residues of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in forty-eight (48) composite fruit and vegetable samples (carrot, cucumber, tomato, and watermelon) were qualitatively and quantitatively determined using gas chromatography equipped with electron capture detector (GC-ECD). Safety indices such as the estimated average daily intake (EADI), cancer benchmark concentration (CBC), hazard quotient (HQ) and index (HI), and hazard ratio (HR) were also estimated. Results showed the predominance of HCH and its isomers in the fruits and vegetables as compared with the DDTs. The most predominant HCHs in all the fruits was α-HCH with mean concentrations of 2.704 ± 2.488 mg kg⁻¹ (carrot), 1.536 ± 1.036 mg kg⁻¹ (cucumber), 6.814 ± 2.967 mg kg⁻¹ (tomato), and 9.241 ± 2.735 mg kg⁻¹ (watermelon). The analysis showed that the levels of pesticide residues detected in 25 to 100% of the fruit and vegetable samples were above the UK/European Commission Maximum Residue Limits (MRLs). The non-carcinogenic health risk estimates showed that only α-HCH in tomatoes and watermelon had HQ > 1 which indicates the possibility of systemic health risk in children consumers. The carcinogenic health risk showed that only α-HCH and γ-HCH in children and α-HCH in adults had HR > 1 for tomato and watermelon which implies the possibility of carcinogenic health risk from its consumption. It is therefore paramount to institute a policy and regulatory framework for regular monitoring of pesticide residues in fruits and vegetables in Nigeria in order to ensure food safety for consumers and protect human health.
显示更多 [+] 显示较少 [-]Does the adsorbent capacity of orange and banana peels toward silver nanoparticles improve the biochemical status of Oreochromis niloticus? 全文
2021
Abdel-Khalek, Amr Adel | Hamed, Aliaa | Hasheesh, Wafaa S.F.
Silver nanoparticles (Ag NPs) have wide medical and industrial applications; therefore, their release into aquatic environments is a problematic issue. The present study aims to evaluate the removal efficiency of Ag NPs from water using orange peel (OP) and banana peel (BP) to moderate their toxicity on Oreochromis niloticus. Fish were divided into 4 groups: control group (dechlorinated tap water), Ag NPs (4 mg/L) exposed group, Ag NPs (4 mg/L) + OP (40 mg/L) group, and Ag NPs (4 mg/L) + BP (40 mg/L) group for 24 h, 48 h, and 96 h. The adsorptive ability of both peels was confirmed by scanning electron microscope and energy-dispersive X-ray spectroscopy after the exposure processes. The biochemical results revealed a gradual elevation in plasma glucose, total proteins, globulin, liver enzymes (AST, ALT, and ALP), creatinine, and uric acid after Ag NPs exposure, while albumin and total lipid concentrations were significantly decreased. The recorded antioxidant biomarkers in gills, and liver tissues after Ag NPs exposure showed severe oxidative damages (maximally after 96 h) as indicated by marked elevations in thiobarbituric acid reactive substances, glutathione peroxidase, catalase, and superoxide dismutase values, and decreased glutathione reduced content. All studied parameters restored more or less to that of control groups after OP and BP water treatment. The adsorbent abilities of both peels could reduce Ag NPs bioavailability and moderate their toxicological impacts.
显示更多 [+] 显示较少 [-]A review of frameworks for using bryophytes as indicators of climate change with special emphasis on Sri Lankan bryoflora 全文
2021
Sumudu Ruklani, N. C. | Rubasinghe, Sumudu C. K. | Jayasuriya, Gehan
The tropical island of Sri Lanka, with a land area of 65,610 km² and 1340 km of coastline, is highly vulnerable to impacts of climate change, with detrimental effects on agriculture, water resources, human health, coastal zones, infrastructure, industry, and biodiversity. A general increase in temperature and precipitation patterns, rising sea levels, and increase in weather-related natural disasters, such as floods and droughts, have been traced over the years. Bryophytes (liverworts, mosses, hornworts) occupy a pivotal position in the land plant evolution and form a unique part of the vegetation. Many taxa of bryophytes exhibit observable, distinct adaptations in response to changes in environmental conditions quickly. Bryophytes can be used to monitor climate change in two ways; (i) presence or absence in the ecosystem and (ii) changes in morphology and physiology that can be used for monitoring. Sri Lanka has a rich bryophyte flora consisting of 575 species of mosses, 338 species of liverworts, and 07 species of hornworts. It is estimated that 11% of mosses are endemic; there are no endemic thalloid liverworts or hornworts found in Sri Lanka, and the endemicity of leafy liverworts is yet to be investigated. The taxonomic status of endemic taxa and the biogeographic affinities of many taxa remain unexplored. Further, the potential use of bryophytes as indicators of climate change in Sri Lanka has not yet been investigated. This paper compiles the information on morphological and physiological responses of bryophytes to elevated temperature, increase in greenhouse gases, increased ultraviolet-B (UV-B) radiation, and fluctuations in humidity. In the light of this gathered global knowledge, possible species of bryophytes to be used in assessing and predicting climate change and developing a climate change model in Sri Lanka are proposed. Asian bryophytes, in general, have poorly been represented in climate change literature. We believe that this knowledge will form the foundation for future research focused on climate change mitigation in other tropical and Asian countries.
显示更多 [+] 显示较少 [-]Mesocosm and Microcosm Bioassays to Examine Effects of Mine-Influenced Sediments on the Growth of Wild Rice (Zizania palustris L.) 全文
2021
Tedrow, O’Niell R. | Lee, Peter F.
Wild rice (WR; Zizania palustris L.) growth response to sediment obtained from Rat River Bay (RRB; control site), Cleaver Lake (CL; legacy zinc-copper mine influenced), and Unnamed Lake (UL; active gold mine influenced) was evaluated by two bioassay systems: (1) a mesocosm-scale bioassay and (2) an accelerated-growth microcosm-scale bioassay. Following an entire growing season of 7 weeks, WR developed to near reproductive maturity, with similar observations using both systems. WR height (HT), dry weight biomass (DWB), and seed production (SP) were statistically higher in RRB than both CL and UL sediment-grown plants. Significant differences were not identified between mesocosm:microcosm ratios for DWB or SP; HT ratios were significant. Wild rice HT, DWB, and SP were statistically lower for CL and UL sediment-grown plants; however, visual differences in growth between sediments were documented mid-season. By the end of the season, ammonia–nitrogen (N) was below detection in CL and UL sediment and decreased by 93% in RRB sediment. Responses of WR to these sediment exposures appeared to be more influenced by ammonia-N concentration than other sediment constituents. Based on data obtained during this study, the microcosm-scale bioassay accurately represented the mesocosm-scale bioassay in terms of WR DWB and SP, both of which were visually recognized. Use of this microcosm-scale bioassay to obtain accurate representations of WR responses to site-specific sediment, or water, exposures can save industry and critical water resource managers time, money, and overall resources.
显示更多 [+] 显示较少 [-]Sustainable management of water demand using fuzzy inference system: a case study of Kenyir Lake, Malaysia 全文
2021
Mohd Azlan, Nor Najwa Irina | Abdul Malek, Marlinda | Zolkepli, Maslina | Mohd Salim, Jamilah | Ahmed, Ali Najah
Sustainable water demand management has become a necessity to the world since the immensely growing population and development have caused water deficit and groundwater depletion. This study aims to overcome water deficit by analyzing water demand at Kenyir Lake, Terengganu, using a fuzzy inference system (FIS). The analysis is widened by comparing FIS with the multiple linear regression (MLR) method. FIS applied as an analysis tool provides good generalization capability for optimum solutions and utilizes human behavior influenced by expert knowledge in water resources management for fuzzy rules specified in the system, whereas MLR can simultaneously adjust and compare several variables as per the needs of the study. The water demand dataset of Kenyir Lake was analyzed using FIS and MLR, resulting in total forecasted water consumptions at Kenyir Lake of 2314.38 m³ and 1358.22 m³, respectively. It is confirmed that both techniques converge close to the actual water consumption of 1249.98 m³. MLR showed the accuracy of the water demand values with smaller forecasted errors to be higher than FIS did. To attain sustainable water demand management, the techniques used can be examined extensively by researchers, educators, and learners by adding more variables, which will provide more anticipated outcomes.
显示更多 [+] 显示较少 [-]Enhanced surface properties, hydrophobicity, and sorption behavior of ZnO nanoparticle–impregnated biomass support for oil spill treatment 全文
2021
Akpomie, Kovo G. | Conradie, Jeanet
Metallic nanoparticles (NPs) have gained significant attention in recent years due to their efficiency in the adsorption of water pollutants. Except for magnetic NPs, metallic NPs are rarely used in oil sorption studies, due to the difficulty in recovering the NPs from the treated water. This study reports for the first time the application of ZnONPs for oil spill treatment. The ZnONPs were impregnated onto Musa acuminata peel (MP) support to form a novel material (ZnOMP), which was utilized for the sorption of oil from synthetic oil spills. The as-prepared sorbents were characterized by the SEM, EDS, BET, FTIR, FE-SEM, TGA, and XRD techniques. The presence of 31.32-nm average-sized ZnONPs enhanced the oil uptake characteristics, with clear affinity for the oil phase in comparison to the pristine MP. A maximum sorption capacity of 4.146 g/g and 5.236 g/g was obtained for biosorbents MP and ZnOMP, respectively, which was higher than most reported sorbents. The Freundlich model presented the best fit for the isotherm data, while the pseudo-second-order model was most suited for the kinetics. The presence of competing heavy metal ions in solution did not have any significant effect on the oil sorption capacity onto ZnOMP. The sorption mechanism was attributed to absorption and hydrophobic interactions. ZnONPs impregnated onto the biomass enhanced the spontaneity of oil uptake at higher temperatures. Over 82% desorption of the oil contaminant from the biosorbents was achieved during recovery, using petroleum ether and n-pentane as eluents. Concisely, ZnONPs enhanced the uptake and hydrophobic characteristic of MP biomass and showed good recovery and reusability. Thus, the application of ZnONPs impregnated onto biosorbents in oil spill treatment is highly recommended.
显示更多 [+] 显示较少 [-]Molecular model construction of Danhou lignite and study on adsorption of CH4 by oxygen functional groups 全文
2021
Zhu, Hongqing | Huo, Yujia | He, Xin | Wang, Wei | Fang, Shuhao | Zhang, Yilong
In view of the frequent occurrence of gas accidents in coal mines, the mechanism of oxygen-containing functional groups (OCFGs) in Danhou lignite adsorbing gas was studied by experiment and simulation. Elemental analysis, X-ray photoelectron spectroscopy (XPS), solid-state ¹³C nuclear magnetic resonance spectroscopy (¹³C-NMR), and adsorption experiment of CH₄ were applied to establish the macromolecular model of Danhou lignite. Then, molecular mechanics (MM) and molecular dynamics (MD) were utilized to optimize the coal macromolecular model, and the density of coal was determined via adding periodic boundary conditions. The mechanism of gas adsorption by OCFGs was studied by grand canonical Monte Carlo (GCMC) and density functional theory (DFT). The results showed that the aromatic structures mostly exist in the form of pyrenes; the structure of aliphatic carbons are mostly methylene and methine groups; the alkanes are mostly long chains; oxygen atoms are mainly in the form of hydroxyl groups and ether groups; nitrogen atoms are mainly in the form of pyridines; and the density of Danhou lignite is 1.25 g/cm³. The isotherm adsorption curve and Langmuir adsorption curve have a good fit, a single coal molecule reaches saturation after absorbing four CH₄ molecules, and the error between experiment and simulation is small. The results of DFT calculation showed that the adsorption of CH₄ by OCFGs is affected by the adsorption positions and adsorption directions. Due to CH₄ molecules are affected by different electrostatic forces, the adsorption capacities of OCFGs are different, and the order is carbonyl groups > ether bonds > hydroxyl groups > carboxyl groups. The results can be used for reference in the prevention and control of coal and gas outburst.
显示更多 [+] 显示较少 [-]Greenhouse gas emission from rice fields: a review from Indian context 全文
2021
Gupta, Khushboo | Kumar, Raushan | Baruah, Kushal Kumar | Hazarika, Samarendra | Karmakar, Susmita | Bordoloi, Nirmali
Agricultural soil acts as a source and sink of important greenhouse gases (GHGs) like methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂). Rice paddies have been a major concern to scientific community, because they produce the threatening and long-lasting GHGs mainly CH₄ and N₂O. Around 30% and 11% of global agricultural CH₄ and N₂O, respectively, emitted from rice fields. Thus, it is urgent to concurrently quantify the fluxes of CH₄ and N₂O to improve understanding of both the gases from rice fields and to develop mitigation strategies for upcoming climate change reduction. An effort is being made in this review to discuss exclusively the emission of CH₄ and N₂O under normal and controlled conditions in different locations of India and also addresses the current synthesis of available data on how field and crop management activities influence CH₄ and N₂O emissions in rice fields. Making changes to conventional crop management regimes could have a significant impact on reducing GHG emissions from rice field. Environmental and agricultural factors related to soil could be easily altered by management practices. So, knowing the mechanism of CH₄ and N₂O production and release in the rice field and factors controlling the emissions is fundamental to develop well-organized strategies to reduce emissions from rice cultivated soil. This will help the regulatory bodies or policy makers to formulate adequate policies for agricultural farmers to refine the GHG emissions as well as minimize the global climate change.
显示更多 [+] 显示较少 [-]Assessing effects of chronic heavy metal exposure through a multibiomarker approach: the case of Liomys irroratus (Rodentia: Heteromyidae) 全文
2021
De la Cruz-Guarneros, Natalia | Tovar-Sánchez, Efraín | Mussali-Galante, Patricia
Wild animals that inhabit inside mine tailings which contain heavy metals are an excellent study model to conduct ecotoxicological studies that analyze chronic metal exposures at low doses (realistic exposures). This study was conducted in Huautla, Morelos, Mexico, in a mining district where 780,000 tons of wastes were deposited in open air. Liomys irroratus is a small mammal species that lives inside these mine tailings. A multibiomarker approach study was performed to analyze metal bioaccumulation levels (biomarker of exposure) by inductively coupled plasma mass spectrometry, DNA damage levels (biomarker of early effects) through the alkaline comet assay, and population genetic structure and diversity (biomarker of permanent effects), using seven microsatellite loci, in 75 L. irroratus individuals, from two mine tailings and one reference site. Concentrations of aluminum, copper, iron, nickel, lead, and zinc were statistically higher in the liver of exposed individuals. Significant DNA damage levels were registered in the mine tailings groups. Aluminum, lead, and nickel had the highest contribution to the genetic damage levels observed, while aluminum and nickel had the highest contribution to genetic diversity effects. A positive and significant relationship was detected between individual genetic diversity (internal relatedness) and genetic damage (DNA single-strand breaks). Genetic structure of L. irroratus populations revealed that the main source of genetic variation was located within populations. We consider that multibiomarker studies in environmental settings using sentinel species are valuable for environmental risk assessment and ecological responses in chronic exposed populations.
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