Refinar búsqueda
Resultados 1081-1090 de 4,042
A novel approach for estimating the removal efficiencies of endocrine disrupting chemicals and heavy metals in wastewater treatment processes Texto completo
2016
Chiu, Jill M.Y. | Degger, Natalie | Leung, Jonathan Y.S. | Po, Beverly H.K. | Zheng, Gene J. | Richardson, Bruce J. | Lau, T.C. | Wu, Rudolf S.S.
A novel approach for estimating the removal efficiencies of endocrine disrupting chemicals and heavy metals in wastewater treatment processes Texto completo
2016
Chiu, Jill M.Y. | Degger, Natalie | Leung, Jonathan Y.S. | Po, Beverly H.K. | Zheng, Gene J. | Richardson, Bruce J. | Lau, T.C. | Wu, Rudolf S.S.
The wide occurrence of endocrine disrupting chemicals (EDCs) and heavy metals in coastal waters has drawn global concern, and thus their removal efficiencies in sewage treatment processes should be estimated. However, low concentrations coupled with high temporal fluctuations of these pollutants present a monitoring challenge. Using semi-permeable membrane devices (SPMDs) and Artificial Mussels (AMs), this study investigates a novel approach to evaluating the removal efficiency of five EDCs and six heavy metals in primary treatment, secondary treatment and chemically enhanced primary treatment (CEPT) processes. In general, the small difference between maximum and minimum values of individual EDCs and heavy metals measured from influents/effluents of the same sewage treatment plant suggests that passive sampling devices can smooth and integrate temporal fluctuations, and therefore have the potential to serve as cost-effective monitoring devices for the estimation of the removal efficiencies of EDCs and heavy metals in sewage treatment works.
Mostrar más [+] Menos [-]A novel approach for estimating the removal efficiencies of endocrine disrupting chemicals and heavy metals in wastewater treatment processes Texto completo
2016
Chiu, J. | Degger, N. | Leung, J. | Po, B. | Zheng, G. | Richardson, B. | Lau, T. | Wu, R.
Abstract not available | Jill M.Y.Chiu, Natalie Degger, Jonathan Y.S.Leung, Beverly H.K.Po, Gene J.Zheng, Bruce J.Richardson, T.C.Lau, Rudolf S.S.Wu
Mostrar más [+] Menos [-]Biocompatible poly(vinyl alcohol) nanoparticle-based binary blends for oil spill control Texto completo
2016
Fouad, Rasha Refaat | Aljohani, Hind Abdullah | Shoueir, Kamel Rizq
In the current study, biocompatible and biodegradable blends based on poly(vinyl alcohol) nanoparticles – PVAn mixed with either chitosan (Ch) or starch (St) – were prepared and investigated as nanoabsorbents for oil elimination from wastewater. The use of water/dimethyl sulfoxide (DMSO) as a mixed solvent is the key factor for preparing aggregated PVAn, which is further mixed with Ch or St. Nanoblends were applied as oil absorbents, and the results showed that PVAn/St possess high adsorption capacity than PVAn/Ch and PVAn. The maximum sorption capacities (qg/g) of the PVAn/Ch sorbents for hydraulic oil, kerosene, and toluene were 33.6, 73.96, and 93.1g/g, respectively. The absorbed oil could be rapidly recovered by simple mechanical squeezing and reused without any other modification. The blends showed excellent reusability and could be reused for at least 10 times with minimal losses. The current study demonstrates the application of these blends as an ideal alternative sorbent for oil spillage cleanup.
Mostrar más [+] Menos [-]Heavy metal pollution monitoring with foraminifera in the estuaries of Nellore coast, East coast of India Texto completo
2016
Sundara Raja Reddy, B.C. | Jayaraju, N. | Sreenivasulu, G. | Suresh, U. | Reddy, A.N.
A total of 112 bottom water and sediment samples collected at fixed stations in pre-monsoon and post-monsoon from four estuaries (Pennar, Uppateru, Swarnamukhi, and Kalangi) showed foraminiferal test abnormalities in heavy metal concentrations (Co, Cr, Cu, Fe, Mn, Ni, and Pb). Low diversity of fauna was due to the predominance of a limited number of opportunistic species capable of achieving high densities in adverse environmental conditions and the reduction in the number of species intolerant of such conditions. In this study, classification of 54 common species according to their distribution is presented. Approximately 15 species showed quite low diversities at stations 23–27 and 44–51. Because of the effect of heavy metal pollution in these estuaries, drastic changes in the number of species and diversity of foraminifera were observed. These changes in foraminiferal species and the increase in test abnormalities are proxies of environmental stress on the estuarine ecosystem.
Mostrar más [+] Menos [-]Metabolic responses to metal pollution in shrimp Crangon affinis from the sites along the Laizhou Bay in the Bohai Sea Texto completo
2016
Xu, Lanlan | Ji, Chenglong | Zhao, Jianmin | Wu, Huifeng
Marine environment in the Laizhou Bay is potentially contaminated by metals from industrial discharges. In this study, metal concentrations in shrimps Crangon affinis indicated that two typical sites (S6283 and S5283) close to Longkou and Zhaoyuan cities along the Laizhou Bay have been contaminated by metals, including Cd, As, Cu, Ni, Co, and Mn. In particular, Cd and As were the main metal contaminants in S6283. In S5283, however, Cu was the most important metal contaminant. The metabolic responses in the shrimps indicated that the metal pollution in S6283 and S5283 induced disturbances in osmotic regulation and energy metabolism and reduced anaerobiosis, lipid metabolism, and muscle movement. However, alteration in the levels of dimethylglycine, dimethylamine, arginine, betaine, and glutamine indicated that the metal pollution in S5283 induced osmotic stress through different pathways compared to that in S6283. In addition, dimethylamine might be the biomarker of Cu in shrimp C. affinis.
Mostrar más [+] Menos [-]Unmanned vehicles for maritime spill response case study: Exercise Cathach Texto completo
2016
Dooly, Gerard | Omerdic, Edin | Coleman, Joseph | Miller, Liam | Kaknjo, Admir | Hayes, James | Braga, José | Ferreira, Filipe | Conlon, Hugh | Barry, Hugh | Marcos-Olaya, Jesús | Tuohy, Thomas | Sousa, João | Toal, Dan
This paper deals with two aspects, namely a historical analysis of the use of unmanned vehicles (UAVs ROVs, AUVs) in maritime spill incidents and a detailed description of a multi-agency oil and HNS incident response exercise involving the integration and analysis of unmanned vehicles environmental sensing equipment. The exercise was a first in terms of the level of robotic systems deployed to assist in survey, surveillance and inspection roles for oil spills and harmful and noxious substances.
Mostrar más [+] Menos [-]PCDD/Fs in soil and air and their possible sources in the vicinity of municipal solid waste incinerators in northeastern China Texto completo
2016
Meng, Bo | Ma, Wanli | Liu, Li-Yan | Zhu, Ning-Zheng | Song, Wei-Wei | Lo, Ching Yee | Li, James | Kannan, Kurunthachalam | Li, Yi-Fan
Fly ash, flue gas, ambient air, and soil samples were collected to investigate concentrations, profiles, gas–particle partitioning, and air–soil exchange of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the vicinity of two municipal solid waste incinerators (MSWIs) in Harbin in northeastern China. The PCDD/F concentrations were 11 600–12 300 pg g−1 (597–615 pg WHO-TEQ g−1) in fly ash and 873–1120 fg m−3 (51.2–61.9 fg WHO-TEQ m−3) in air. The results of gas–particle partitioning possibly indicated the equilibrium state of PCDD/F during sampling period. For soil samples, both Enzyme-linked immuno-sorbent assay (ELISA) and high-resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) were used. Significant correlations between the results from these two methods indicated that both methods are useful for PCDD/Fs analysis in soil. PCDD/Fs concentrations in soil samples ranged from 17.2 to 157 pg g−1 (0.59–8.81 pg WHO-TEQ g−1). Both Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) suggested the sources of the emission from MSWIs and the historical emission from a petroleum refinery to PCDD/Fs in adjacent soils. The air–soil exchange analysis showed a net flux of PCDD/F from air to soil at all soil-sampling sites.
Mostrar más [+] Menos [-]Synergistic effect of elevated temperature, pCO2 and nutrients on marine biofilm Texto completo
2016
Baragi, Lalita V. | Anil, Arga Chandrashekar
Natural marine biofilms provide signatures of the events that occur over a period of time and can be used as bioindicators of environmental changes. Hence, the effects of temperature (30 and 34°C), pCO2 (400 and 1500μatm) and nutrients (unenriched and enriched f/2 media) on the marine biofilm were evaluated using a 2×2×2 factorial design. In unenriched condition, acidification significantly increased the abundance of phytoperiphytes whereas reduced that of bacteria and it was vice versa in the enriched condition. Warming had significant negative effect on the abundance of both phytoperiphytes and bacteria, except in unenriched condition wherein it favoured bacterial growth. Synergistically, acidification and warming had deleterious effects resulting in further reduction in the abundance of both phytoperiphytes and bacteria, except in enriched condition wherein bacterial abundance increased. Such changes in biofilm communities in response to warming and acidification can have cascading effect on the subsequent build-up of macrofouling community.
Mostrar más [+] Menos [-]Is meiofauna community structure in Artificial Substrate Units a good tool to assess anthropogenic impact in estuaries? Texto completo
2016
Costa, Ana Bolena Harten Pinto | Valença, Ana Paula Maria Cavalcanti | Santos, Paulo Jorge Parreira dos
The applicability of estuarine meiofauna and harpacticoid copepods' communities in an artificial substrate unit (ASU) was assessed and compared to natural substrates (sediment and pneumatophores) as a tool to discern estuaries under different types of anthropogenic impacts. The ASU's replicates demonstrated a low variation of density among replicates when considering the total meiofauna and copepod species, which was reflected by a great similarity within the samples. In relation to the most abundant groups found, the ASU samples properly represented the natural substrates, even though nematodes were poor colonizers. That the ASU only showed significant differences between areas suggested that standard substrates could more efficiently detect the differences between communities and pointed toward the applicability of ASUs meiobenthic communities as useful tools for impact studies.
Mostrar más [+] Menos [-]Assessing genotoxic effects in fish from a marine protected area influenced by former mining activities and other stressors Texto completo
2016
Gusso-Choueri, Paloma Kachel | Choueri, Rodrigo Brasil | Santos, Gustavo Souza | de Araújo, Giuliana Seraphim | Cruz, Ana Carolina Feitosa | Stremel, Tatiana | de Campos, Sandro Xavier | Cestari, Marta Margarete | Ribeiro, Ciro Alberto Oliveira | de Sousa Abessa, Denis Moledo
The goal of the current study was to evaluate different genotoxicity tools in order to assess a marine protected area (MPA) affected by former mining activities and urban settlements. A catfish (Cathorops spixii) was analyzed for genotoxic effects at the (i) molecular and at the (ii) chromosomal levels. Through factor analysis, genotoxicity was found to be linked to levels of metals bioaccumulated and PAH metabolites in the bile. Micronucleus and nuclear alteration were less vulnerable to the effects of confounding factors in mildly contaminated areas since they were more frequently associated with bioaccumulated metals than the DNA analysis. The different genotoxicity responses allowed for the identification of sources of pollution in the MPA. This approach was important for detecting environmental risks related to genotoxic contaminants in a mildly contaminated MPA.
Mostrar más [+] Menos [-]Bioaccumulation of heavy metals in marine organisms and sediments from Admiralty Bay, King George Island, Antarctica Texto completo
2016
Trevizani, Tailisi Hoppe | Figueira, Rubens Cesar Lopes | Ribeiro, Andreza Portella | Theophilo, Carolina Yume Sawamura | Majer, Alessandra Pereira | Petti, Mônica Angélica Varella | Corbisier, Thais Navajas | Montone, Rosalinda Carmela
The Antarctic continent is considered a low-impact environment; however, there is a tendency to increase the contaminants' levels due to human activities in the research stations. In this study, As, Cd, Cr, Cu, Hg, Ni, Pb and Zn levels in sediment and biota were determined in the environmental samples from Admiralty Bay (King George Island, Antarctica) collected in 2003. The results demonstrated high concentrations of Cu and Zn in the sediments. There was bioaccumulation of As in the biota from Admiralty Bay and bioaccumulation of Zn specifically in the biota from Martel Inlet. In addition, the results were useful in order to understand the heavy metal levels for the pre-accident condition of Comandante Ferraz Antarctic Station, where an accident occurred in 2012, and also for the comparison with current conditions within the monitoring work developed by INCT-APA (National Institute of Science and Technology for Environmental Research Antarctic).
Mostrar más [+] Menos [-]