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Bioaccumulation of Heavy Metals in Fish Sourced from Environmentally Stressed Axis of River Niger: Threat to Ecosystem and Public Health
Ezeonyejiaku Chigozie Damian,
Nwuba Lucy Afulenu,
Obiakor Maximilian Obinna,
Okonkwo Chidumeje Ndidi
Issue:
Volume 2, Issue 4, July 2014
Pages:
126-131
Received:
21 June 2014
Accepted:
30 June 2014
Published:
10 July 2014
Abstract: Pollution of freshwater ecosystems is alarmingly becoming high in Nigeria with attendant public health effects on the dependent populations. Fish, a source of protein with pronounced placement on local food menu is now considered an important dietary threat of heavy metal toxicity via consumptions. Bioaccumulation of heavy metals (copper, zinc and lead) in Silver catfish (Schilbe intermedius) from River Niger was conducted. The Fish samples were collected from different sites of Onitsha axis of the River Niger owing to their environmental stresses. Samples were analyzed for heavy metal (copper- Cu, zinc- Zn, and lead- Pb) concentrations in muscle tissues using the Atomic Absorption Spectrophotometer (AAS) and compared with Food and Agriculture Organization safe limits. Margin of exposure (MOE) was estimated to measure the potential public health risk of consuming the contaminated fish. The concentrations of heavy metals (Cu- 8.92±4.748, Zn- 0.36±0.249, and Pb- 2.689±1.505) observed were significant (P<.05) with diversity in different experimental locations and Cu recording highest pooled mean concentrations. The trend of the metal occurrences was Cu>Pb>Zn. Statistical Pearson moment correlation analysis showed that the concentrations of heavy metals detected were independent of the weight of sampled fish for zinc but was positively correlated for copper and lead. Relating the mean metal concentrations obtained in the study with Food and Agriculture Organization standard for fish muscles indicated that mean concentrations of copper, zinc and lead are far above safe margins for human consumption except the fish sourced from sites A4 and A9 for lead and zinc, respectively. Margin of exposure was below one and tentatively considered not to be of risk to public health. However, there is considerable contamination of the Silver catfish from the River Niger with heavy metals. It is recommended that substantial attention be paid to the heavy metal levels in freshwater fishes from the river. Measures should be put in place to regulate the indiscriminate dredging activities, discharge of raw sewage and industrial effluent into the river and regular public health check on the level of heavy metals among the populace in the communities that border the area should be employed.
Abstract: Pollution of freshwater ecosystems is alarmingly becoming high in Nigeria with attendant public health effects on the dependent populations. Fish, a source of protein with pronounced placement on local food menu is now considered an important dietary threat of heavy metal toxicity via consumptions. Bioaccumulation of heavy metals (copper, zinc and ...
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Status of Recycling Plastic Bottles in Japan and a Comparison of the Energy Costs of Different Recycling Methods
Masakazu Yamashita,
Shin-ichiro Matsumoto
Issue:
Volume 2, Issue 4, July 2014
Pages:
132-137
Received:
20 April 2014
Accepted:
8 May 2014
Published:
10 August 2014
Abstract: The present study explains the status of recycling plastic bottles in Japan and recycling methods, and examines whether or not they are effective in terms of reducing energy consumption. The results of the study suggest that it is unwise to use plastic bottles as containers for tea, water, soft drinks, and other beverages in the first place, and that the recycling of plastic bottles is a waste of energy. It is better to combust used plastic bottles, rather than recycle them, to produce and utilize heat.
Abstract: The present study explains the status of recycling plastic bottles in Japan and recycling methods, and examines whether or not they are effective in terms of reducing energy consumption. The results of the study suggest that it is unwise to use plastic bottles as containers for tea, water, soft drinks, and other beverages in the first place, and th...
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Trends and Shifts in Time Series of Rainfall and Runoff in the Gambia River Watershed
Vieux Boukhaly Traore,
Soussou Sambou,
Mohamed Talla Cisse,
Séni Tamba,
Sidy Fall,
Amadou Tahirou Diaw,
Hyacinthe Sambou,
Malanda Edmond Nimy
Issue:
Volume 2, Issue 4, July 2014
Pages:
138-146
Received:
7 August 2014
Accepted:
20 August 2014
Published:
30 August 2014
Abstract: For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and a comprehensive diagnosis of the existing trends and shifts in these time series of data. This can be done by applying robust statistical tests to relevant rainfall and runoff time annual series. The aim of this paper is to highlight the effect of climate change in the Gambia River Basin and its impacts on the availability of the water resources of this basin. To reach this objective, we have selected runoff time series of the Gambia River Basin at Mako, Kedougou Diaguéri streamgauges and rainfall time series at Koulountou’s rain gauge. Statistical tests for shift detection presented in the Khronostat software, such as Pettit, Hubert and Buishand ellipse tests are first used, Mann Kendall test for annual trend are then applied to check whether trends exist or not in these times series. When the null hypothesis of no trend is rejected, the non parametric Sen’s test is then applied to validate the Mann Kendall trend test and to estimate the magnitude of the trend and its direction. Tests for homogeneity show an increasing shift for rainfall time series of Koulountou raingauge and for runoff time series of Mako and Diaguéri and a decreasing shift for Kedougou streamgauge. According to the Mann Kendall trend test, there is an upward trend for Koulountou rainfall time series, and Mako and Diaguéri runoff time series, and a downward trend for Kedougou annual runoff time series. The Buishand ellipse and the Hubert test indicate generally the same year of the beginning of the shift. Interesting perspectives for decision makers in evaluation and precise management of water resources and water projects in the Gambia River basin are offered as well.
Abstract: For several decades, climate change and climate variability issues and their impacts on the hydrological regime of rivers have constituted a major topic for hydroclimatological sciences research and water resources planning policies. Understanding of these issues needs enough long time series of rainfall and runoff data covering a large period, and...
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