958 resultados para Pollution de l’air
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Although other research studies on areas such as the physical-chemical, nutrients and phytoplankton status of Lake Kyoga systems have been given a lot of attention (e.g. Mungoma 1988 and NaFIRRI 2006), efforts to determine the pollution status of this system, especially by heavy metals as one of the worldwide emerging environmental problems, is still limited. Many trace metals are regarded as serious pollutants of aquatic ecosystems because of their persistence, toxicity and ability to be incorporated into food chains (Mwamburi J., and Nathan O.F., 1997). Given the rapid human population growth and the associated economic activities both within the rural and urban areas in Uganda, such fish production systems are becoming very prone to various kinds of pollution including that by heavy metals. Anthropogenic factors such deforestation, use of chemicals and dumping of metallic products, spillages of fuels from outboard engines and many others and or natural processes involving atmospheric deposition by wind or rain, surface run-offs and streams flows from the catchment introduces heavy metals into the lake environment,.
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The configuration for the eastern side of the Gulf of Suez was studied over 241 km from Ras Mohammed to Ras Sudr including 35 station. Litters, tar balls and aged oil patches aggregated in considerable amounts on the beach and shore line of the middle part due to the oil spills from off-shore oil wells. A large reef flat in the shallow intertidal waters exists at stations 1 and 2 (Ras Mohammed, Protected area) and spars coral patches are less frequent at the Stations from 7 to 13. Density and diversity of marine benthos were higher on hard and cobble bottoms compared to muddy sand and sandy substrates. The assemblages of the benthic fauna are dominated by the gastropod Courmya (Thericium) vulgata; the bivalve Brachiodontes variabilis, and the barnacles Chthamalus stellatus, Balanus amphitrite and Tetraclita rubescens. The distribution of the algal cover in the intertidal region shows high abundance of the brown algae, Sargassum latifolium; padina pavonica and Cystoseira trinodis rather than the green and red algae. These species are found in both polluted and unpolluted areas. The changes in benthic structures in the study area depend not only on the state of pollution but also on the type of substrates.
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Adverse effects of toxic substances on the environmental quality have become a subject of concern in recent years. Toxicity of heavy metals has never been in dispute and therefore their presence in our natural environment is undesirable. This study was undertaken to establish the capability of Perna viridis as a monitor for pollution in the Manora channel. Accumulation of Zinc, Copper, Iron and Manganese by marine mussels, sampled from Manora channel, was determined. Metal load varied markedly between individuals from the same populatin. This variability was partly accounted for systematic relationship between metal load and body weight and age. The distribution of metal between the major organs was considered, but the analysis of separate organs showed no advantage for their use as a biological monitor. comparison between Iron, Manganese, Copper and Zinc concentration in ambient sea water and in the mussel showed no clear correspondence. The results suggest that the mussel is capable of acting as a biological monitor, although may not be a good short term monitor of Iron, Manganese, Zinc and Copper. It may have potential as a long term and site comparison monitor for metals, once inherent variability is taken into account
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The Buniyar hydroelectric project and the lower Jhelum Barrier at Gantamulla constructed across river Jhelum are in operation from several years. The two power stations have changed the hydrological features of the area where dam is situated. Therefore, the impact of hydroelectric projects on fishery resources of river Jhelum is a matter of great concern. The treated water from the power house is released through turbines, having cooling effect on them. The change in the hydrological parameters such as increase in temperature, depletion of oxygen etc. might have brought fishes under stress which is the main cause in decreased population of finfishes from site to site. The golden mahseer, Tor putitora which was once an abundant species in river Jhelum has disappeared due to human intervention. The prevailing water quality around hydroelectric projects is unsuitable for finfishes of river Jhelum.
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Penaeus monodon postlarvae were subjected to increasing feed concentrations and their growth and survival rates were recorded. Measurements were made of dissolved organic matter, and ammonia and nitrite-nitrogen concentrations. Survival was highest at the lowest feeding level and decreased as feed concentration increased. It is concluded that although organic matter enriches the food supply for P. monodon postlarvae, at higher concentration levels it can pollute the culture water, which in turn leads to mass mortality of the postlarvae. Secondly, the survival rate of P. monodon postlarvae is directly related to dissolved organic matter concentration, oxygen tension, and ammonia-nitrogen concentrations in the culture water. Even at sublethal levels these adverse environmental conditions decrease the survival rate.
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Meeting to develop environmental indicators to measure overall health of BOBLME; identify important coastal water pollution issues: produce conclusions and recommendations to form an action plan.
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Biogeographical features, coastal ecosystems and coastal activities of the Bay of Bengal Coast of India. Overview of sources of pollution, water and sediment quality. Present status of pollution and trans-boundary issues. International instruments adopted, policy and mechanisms for pollution control and enforcement of existing policies and legislations.
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Ecological risk assessment is determination of the probability of an adverse effect occurring to an ecological system. This investigation was carried out to assess the ecological risk of sediment in coast of Bandar Abbass in 9 stations including Shilat Jetty, Hotel Amin, Poshte-Shahr, Souro, Bahonar Jetty, Powerhouse, Refinery and Rajaee Jetty from autumn 2013 to summer 2014. Results showed that Polychaete with 1177 , 1109 , 414 , 573 , ind.m2 in autumn 91 , winter 91 , spring 92 and summer 92 were the most abundant in frequency respectively. Among ecological indices, the Margalof that ranged from 4 to 7 was in a good situation while Shanoon and Berger – Parker with 1.2 (at most) and 0.32 (at least) respectively indicated an environment with probable stress. Heavy metal distribution obtained as Cd>Pb>Cu>Zn in sediment. In tissue, the distribution of heavy metals were as Crab>polychaete>Bivalve>gastropod for Pb, Gastropod>Bivalve>Polychaete>Crab for Cd, Gastropod>Crab>Polychaete>Bivalve for Cu and Gastropod>Bivalve>Crab>Polychaete for Zn. Maximum and Minimum of TOM obtained 10.16 and 1.96 percent in Posht-e-Shahr and shilat Jetty respectively and clay was the dominant grain in most area. Bioaccumulation coefficient of Zn and Cu was high in all stations. Igeo as a single index was high for Cd indicating a high risk in all stations. Potential Ecological Risk was high for Cu and Zn and goes increasingly from shilat Jetty to Rajee Jetty but goes down for Pb. Pollution index for Cu and Pb was nearly the same as Potential Ecological Risk but for Zn goes constantly. Among PAH, 5-ring and 6-ring PAhs were more concentrate comparison to other compounds in sediment. 2-ring and 3-ring, 3-ring, 4-ring and 5-ring and 5-ring PAHs were more concentrate in Gastropod, Bivalve, Crab and Polychaete respectively. HI as an index of PAH obtained 1. Ecological Risk Indices showed that the heavy metals are a serious risk for invertebrate in sediment but PAHs are not a risk for benthic community.
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The workshop agenda included: presentations from collaborative institutions, national governments and resource persons; a draft scoping study on nutrient loading; and an ecosystem approach to pollution management was tested.
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This study looked at improving knowledge base capacity and enhance capacity to address marine pollution and water quality monitoring issues in Myanmar. Significant capacity needs were identified and a follow up plan presented.
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We investigated differences in delta N-15 of seston and icefishes from seven freshwater ecosystems with different trophic states in China. An increase of seston delta N-15 values was accompanied by an increase of total nitrogen and phosphorus concentrations. Significantly positive correlations were observed between delta N-15 of icefishes and delta N-15 of seston, total nitrogen and phosphorus concentrations. This study demonstrated that icefishes could be preferred indicators of anthropogenic contamination in test systems because they integrated waste inputs over long time periods and reflected the movement of waste through the pelagic food chain.
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The purpose of the research is to study the seasonal succession of protozoa community and the effect of water quality on the protozoa community to characterize biochemical processes occurring at a eutrophic Lake Donghu, a large shallow lake in Wuhan City, China. Samples of protozoa communities were obtained monthly at three stations by PFU (polyurethane foam unit) method over a year. Synchronously, water samples also were taken from the stations for the water chemical quality analysis. Six major variables were examined in a principal component analysis (PCA), which indicate the fast changes of water quality in this station I and less within-year variation and a comparatively stable water quality in stations II and III. The community data were analyzed using multivariate techniques, and we show that clusters are rather mixed and poorly separated, suggesting that the community structure is changing gradually, giving a slight merging of clusters form the summer to the autumn and the autumn to the winter. Canonical correspondence analysis (CCA) was used to infer the relationship between water quality variables and phytoplankton community structure, which changed substantially over the survey period. From the analysis of cluster and CCA, coupled by community pollution value (CPV), it is concluded that the key factors driving the change in protozoa community composition in Lake Donghu was water qualities rather than seasons. (c) 2006 Elsevier Ltd. All rights reserved.
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Goal, Scope and Background. Heavy metal is among one of the pollutants, which cause severe threats to humans and the environment in China. The aim of the present review is to make information on the source of heavy metal pollution, distribution of heavy metals in the environment, and measures of pollution control accessible internationally, which are mostly published in Chinese. Methods. Information from scientific journals, university journals and governmental releases are compiled focusing mainly on Cd, Cu, Pb and Zn. Partly Al, As, Cr, Fe, Hg, Mn and Ni are included also in part as well. Results and Discussion. In soil, the average contents of Cd, Cu, Pb and Zn are 0.097, 22.6, 26.0 and 74.2 mg/kg, respectively. In the water of. the Yangtze River Basin, the concentrations of Cd, Cu, Pb and Zn are 0.080, 7.91, 15.7 and 18.7 pg/L, respectively. In reference to human activities, the heavy metal pollution comes from three sources: industrial emission, wastewater and solid waste. The environment such as soil, water and air were polluted by heavy metals in some cases. The contents of Cd, Cu, Pb and Zn even reach 3.16, 99.3, 84.1 and 147 mg/kg, respectively, in the soils of a wastewater irrigation zone. These contaminants pollute drinking water and food, and threaten human health. Some diseases resulting from pollution of geological and environmental origin, were observed with long-term and non-reversible effects. Conclusions. In China, the geological background level of heavy metal is low, but with the activity of humans, soil, water, air, and plants are polluted by heavy metals in some cases and even affect human health through the food chain. Recommendations and Outlook. To remediate and improve environmental quality is a long strategy for the polluted area to keep humans and animals healthy. Phytoremediation would be an effective technique to remediate the heavy metal pollutions.