خيارات البحث
النتائج 1561 - 1570 من 4,308
Using a liver cell culture from Epinephelus coioides as a model to evaluate the nonylphenol-induced oxidative stress النص الكامل
2017
Derakhshesh, Negin | Movahedinia, AbdolAli | Salamat, Negin | Hashemitabar, Mahmoud | Bayati, Vahid
The present study aimed to use primary liver cell culture derived from the orange-spotted grouper, Epinephelus coioides, to assess the toxic effects of nonylphenol (NP) on the hepatocyte viability and the liver antioxidant system. E. coioides was selected due to its commercial importance. NP was used in this study because of its high potential of producing oxidative stress due to increased reactive oxygen species (ROS). A liver of E. coioides was digested with PBS containing 0.1% collagenase IV. The digested cells were moved to Leibovitz L-15 culture medium with 20% fetal bovine serum (FBS), 100IUmL−1 penicillin, 100μgmL−1 streptomycin. Aliquots of cell suspension were seeded as a monolayer into sterile 25cm2 tissue culture flasks and incubated at 30°C for 14days. The medium, containing non-attached cells, was removed after 24 to 48h and a new medium was added. The IC50 of 10−4molL−1 was determined for nonylphenol using MTT assay. Cells were then incubated with L-15 medium containing 10−5, 2×10−5, 3×10−5molL−1 of NP and samples were taken after 6, 12 and 24h of incubation for analysis of LPO, SOD, CAT, GPx, LDH, AST, ALT, and ALP. Based on the results, the lowest concentration of NP was not markedly cytotoxic to primary hepatocytes and the cell sensitivity to NP increased dose-dependently. The activities of SOD, CAT and GPx decreased significantly, while activities of LPO, LDH, AST, ALT and ALP, increased significantly in a dose-related pattern in NP-treated cells. In conclusion, this study revealed that NP could induce the oxidative stress in cultivated hepatocytes of E. coioides during a short-term exposure. NP toxicity is mainly due to the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.
اظهر المزيد [+] اقل [-]Chlorine dioxide as an alternative antifouling biocide for cooling water systems: Toxicity to larval barnacle Amphibalanus reticulatus (Utinomi) النص الكامل
2017
Venkatnarayanan, Srinivas | Sriyutha Murthy, P. | Kirubagaran, Ramalingam | Venugopalan, Vayalam P.
Chlorine dioxide (ClO2) is seen as an effective alternative to chlorine, which is widely used as an antifouling biocide. However, data on its efficacy against marine macrofoulants is scanty. In this study, acute toxicity of ClO2 to larval forms of the fouling barnacle Amphibalanus reticulatus was investigated. ClO2 treatment at 0.1mg/L for 20min elicited 45–63% reduction in naupliar metamorphosis, 70% inhibition of cyprid settlement and 80% inhibition of metamorphosis to juveniles. Increase in concentration to 0.2mg/L did not result in any significant difference in the settlement inhibition or metamorphosis. Treatment with 0.2mg/L of ClO2 elicited substantial reduction in the settlement of barnacle larvae compared to control. The study indicates the possibility of using ClO2 as an alternative antifouling biocide in power plant cooling water systems. However, more work needs to be done on the environmental effects of such switchover, which we are currently undertaking.
اظهر المزيد [+] اقل [-]Enhanced microbubbles assisted cleaning of diesel contaminated sand النص الكامل
2017
Agarwal, Ashutosh | Liu, Yu
In this article, we investigated the effect of low intensity pulsed ultrasound (US), temperature and salinity on cleaning efficacy of fine bubbles with diameter <50μm for diesel contaminated sands. About 47% and 76% diesel removal was achieved from 10% (w/w) diesel contaminated fine and medium sands respectively, after 30min treatment with 40kHz low intensity intermittent pulsed US together with MBs in contrast to 41% and 68% diesel removal while treatment with MBs alone. The effect of high temperature was found to be prominent during the initial stages of cleaning. In addition, MBs generated in 599mM saline water efficiently removed 85% diesel from fine sand within 30min in contrast to only 41% diesel removal with MBs in fresh water. This study provides evidence for developing highly efficient MBs based chemical free technology for diesel contaminated sediments.
اظهر المزيد [+] اقل [-]Settling of dilbit-derived oil-mineral aggregates (OMAs) & transport parameters for oil spill modelling النص الكامل
2017
O'Laughlin, Casey M. | Law, Brent A. | Zions, Vanessa S. | King, Thomas L. | Robinson, Brian | Wu, Yongsheng
The size and settling velocity of oil-mineral aggregates (OMAs) derived from diluted bitumen are primary constituents in predictive models for evaluating the potential fate of oil spilled in the aquatic environment. A series of low sediment concentration (15mg·L−1), colder water (<10°C) wave tank experiments designed to measure variability in these parameters in naturally-formed OMAs in response the presence or absence of chemical dispersant are discussed. Corresponding lab experiments revealed settling velocities of artificially formed OMAs on the order of 0.1–0.4mm·s−1. High-resolution imagery of settling particles were analyzed for particle size, density and settling velocity. In situ formation of OMAs in the wave tank was unsuccessful. Possible effects of chemical dispersant on natural sediment flocculation, the size of suspended oil droplets and clearance rates of suspended particles are discussed.
اظهر المزيد [+] اقل [-]Management of plastic wastes at Brazilian ports and diagnosis of their generation النص الكامل
2017
Neffa Gobbi, Clarice | Lourenço Sanches, Vânia Maria | Acordi Vasques Pacheco, Elen Beatriz | de Oliveira Cavalcanti Guimarães, Maria José | Freitas, Marcos Aurélio Vasconcelos de
This study evaluated the management of plastic wastes at 20 Brazilian maritime ports, from three sources: vessels, leased and non-leased areas. The data were obtained from documents on port wastes organized in a relational database with defined protocols (closed form). Analysis of the spreadsheets prepared and field visits revealed that the main bottleneck in managing plastic wastes at ports is their segregation. In general, more material is segregated and sent for recycling from leased areas than non-leased ones (administered by the government). This relatively better performance in managing the wastes generated in leased areas is probably due to the need for private operators to comply with the international standards such as the Code of Environmental Practice to satisfy the international market.
اظهر المزيد [+] اقل [-]Bi-species imposex monitoring in Galicia (NW Spain) shows contrasting achievement of the OSPAR Ecological Quality Objective for TBT النص الكامل
2017
Ruiz, J.M. | Carro, B. | Albaina, N. | Couceiro, L. | Míguez, A. | Quintela, M. | Barreiro, R.
Imposex is decreasing worldwide after the total ban on tributyltin (TBT) from antifouling paints. In order to assess improvement in the NE Atlantic, the OSPAR Convention designed an Ecological Quality Objective (EcoQO) based on the VDSI (vas deferens sequence index, an agreed measure of imposex) in the rock snail Nucella lapillus; wherever this is not available, the mud snail Nassarius reticulatus was proposed as a proxy. We determined VDSI in Galician populations of rock (n≥34) and mud (n≥18) snails at regular intervals from pre-ban times until 2009 and 2011, respectively. While imposex in the former started decreasing in 2006 and by 2009 the EcoQO had been met in the area, VDSI in the latter was not significantly reduced until 2011 and values contradict such an achievement. This suggests that the OSPAR imposex bi-species scheme may not be of direct application in the current post-ban scenario.
اظهر المزيد [+] اقل [-]Impact of Middle Eastern Dust storms on human health النص الكامل
2017
Khaniabadi, Yusef Omidi | Daryanoosh, Seyed Mohammad | Amrane, Abdeltif | Polosa, Riccardo | Hopke, Philip K. | Goudarzi, Gholamreza | Mohammadi, Mohammad Javad | Sicard, Pierre | Armin, Houshang
Air pollution is emerging as a significant risk factor for human health in developing countries, particularly in Iran where air pollutant concentrations are elevated. Currently, knowledge of health effects of air pollution in developing countries is limited. The objective of this study was to estimate the excess number of hospitalizations for Chronic Obstructive Pulmonary Disease (COPD) and the number of excess cases of Respiratory Mortality (RM) associated with daily averages levels of particulate matter less than 10 μm in diameter (PM10) in Ilam (Iran) over 1-year period (2015–2016). The excess instances of COPD and RM were estimated based on relative risk (RR) and baseline incidence (BI). The numbers of excess cases for COPD and RM during normal, dusty and Middle Eastern Dust (MED) storm days were 60 and 5, 200 and 15, and 78 and 6 persons, respectively. The results also showed that about 4.9% (95% CI: 3.0–6.8%) of hospital visits for COPD and 7.3% (CI: 4.9–19.5%) of RM could be attributed to 10 μg/m3 increase in PM10 concentration, respectively. It was found that a higher number of people were admitted to hospital when PM10 concentrations exceed 200 μg/m3 related to the MED events. Significant exposure to air pollutants, particularly during MED event, led to an excess of hospital admissions for COPD and an excess of the respiratory mortality. Several immediate actions such as strategic management of water bodies or planting of tree species in suburbs particularly bare area around the city could be effective to mitigate the impact of desert dust on respiratory illness.
اظهر المزيد [+] اقل [-]Degradation of Pharmaceuticals and Personal Care Products by White-Rot Fungi—a Critical Review النص الكامل
2017
Asif, Muhammad B. | Hai, Faisal I. | Singh, Lakhveer | Price, William E. | Nghiem, Long D.
White-rot fungi (WRF) mediated treatment can offer an environmentally friendly platform for the removal of pharmaceuticals and personal care products (PPCPs) from wastewater. These PPCPs may have adverse impacts on aquatic organisms and even human and thus their removal during wastewater treatment is of significant interest to the water industry. Whole-cell WRF or their extracellular lignin modifying enzymes (LMEs) have been reported to efficiently degrade PPCPs that are persistent to conventional activated sludge process. WRF mediated treatment of PPCPs depends on a number of factors including physicochemical properties of PPCPs (e.g., hydrophobicity and chemical structure) and wastewater matrix (e.g., pH, temperature, and dissolved constituents), type of WRF species and their specific extracellular enzymes. This review critically analyzes the performance of whole-cell WRF and their LMEs for the removal of PPCPs; particularly, it offers insights into PPCP removal mechanisms (e.g., biosorption vs. biodegradation) and degradation pathways as well as the formation of intermediate byproducts.
اظهر المزيد [+] اقل [-]Microplastics releasing from personal care and cosmetic products in China النص الكامل
2017
Lei, Kun | Qiao, Fei | Liu, Qing | Wei, Zhanliang | Qi, Hongli | Cui, Song | Yue, Xue | Deng, Yixiang | An, Lihui
Microplastics (MPs) have become a major global issue; their release from various products affects the aquatic environment, especially marine ecosystems. As a primary source of MPs, personal care and cosmetics products (PCCPs) containing MPs contribute to this environmental risk. We visited several supermarket chains in Beijing, China to identify PCCPs containing MPs. Overall, 7.1% of facial cleansers contained MPs, with an average weight of 25.04±10.69mgMP/g and average size of 313±130μm; whereas, 2.2% of shower gel products contained an average weight of 17.80±7.50mgMPs/g with an average size of 422±185μm. The majority of MPs were made of polyethylene, based on Raman and Fourier transform-infrared spectra analyses, while only a few were made of walnut shells and carbon particles. Finally, estimated 39tons MPs were released into the environment based on PCCPs use in China based on available data.
اظهر المزيد [+] اقل [-]Mangrove sediments reveal records of development during the previous century (Coffs Creek estuary, Australia) النص الكامل
2017
Conrad, Stephen R. | Santos, Isaac R. | Brown, Dylan R. | Sanders, Luciana M. | van Santen, Michelle L. | Sanders, Christian J.
A mangrove sediment core was studied to evaluate possible pollution of an urban estuary in Coffs Harbour, Australia. The heavy metal and nutrient profiles revealed a ~2.5-fold enrichment in more recent sediments. Lead-210 dating showed increasing phosphorous (P) and copper (Cu) accumulation following agricultural activity and population growth in the catchment after 1950. In contrast, nitrogen (N) did not show enrichment suggesting no external sources. Mercury (Hg) depositional fluxes and recent enrichment may be associated to an increase in fossil fuel emissions in the region. Down-core lead (Pb) profiles reflect an increase in leaded gasoline in the 1950s, then a decrease as a result of phasing out leaded gasoline in 1986. The heavy metal and nutrient depositional fluxes are well preserved in mangrove sediments and were related to historical events in the catchment.
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