Survey of heavy metals in the catfish Synodontis clarias

International Journal of Environmental Sience and Technology, 12/2007; 4(1):93-97.


Elevated levels of heavy metals in the catfish Synodontis clarias can be a good indication of pollution of an aquatic ecosystem due to anthropogenic influence. The concentrations of Zn, Cd, Pb, Mn and Ni were determined in Synodontis clarias caught along a section of Taylor Creek and its associated tributaries. Samples were collected bimonthly between July 1999 and June 2000 in five stations. The metals: Zn, Cd, Ni, Pb and Mn were recorded in appreciable quantities, signifying their bioavailability. The levels of Zn, Cd, Ni, Pb and Mn may have obvious health implications on the rural communities that depend on fish species as fish supplement in view of its rich protein content and its bio-economic value. Generally, the sources of the metals in the catfish appear to be point and diffuse which include rural and agricultural runoff sources in the catchments area. However, the presence of an oil industry activity (Etelebou oil field and flow station) in one of its tributaries appears to be the major point source of the metal pollutants.

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Available from: Ikem Kris Eloka Ekweozor, Dec 16, 2015
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    • "Metal nutritional requirements differ substantially between species or elements and optimum ranges of concentrations are generally narrow. Severe imbalances on metal proportions caused by exposure to elevated concentrations can induce death even of organisms (Agbozu et al., 2007). Elements like Pb, Cd, As etc. exhibit extreme toxicity even at trace levels (Nicolau et al., 2006). "
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    ABSTRACT: A study was conducted to investigate the trace metal pollution of water and sediments of downstreamof Tsurumi River, Yokohama, Japan. Twenty samples of water and sediments were collected from the river starting fromTokyo bay side up to the junction point of the Yagami River. Results show that the mean concentrations of chromium,cupper and nickel in water greatly exceed (>100 times) the surface water standard. The concentration of molybdenumand lead was also higher than standard values while iron and manganese was lower than that of surface water standard.The mean concentration of zinc, cupper, cadmium, lead, chromium, vanadium, bromine and iodine was 381.1, 133.0, 1.0, 40.8, 102.9, 162.0, 71.5 and 10.6 µg/g sediments, respectively and was greatly exceed the average worldwide shaleconcentrations and average Japanese river sediment values. However, mean concentration of arsenic, nickel and strontiumwas 11.0, 36.6 and 164.6 µg/g sediments, respectively which was lower than the average shale value. Other analyzedtrace metals, including barium, zirconium, rubidium, yttrium, tin, antimony, cesium, lanthanum, cerium, praseodymiumand neodymium were detected in river sediments; the concentration of which was close to the Japan’s river sedimentaverage values. Pollution load index values of the sites of the studied area ranged from 1.24 to 7.65 which testify that theriver sediments are polluted. The PLI value of the area was, however, high (6.53) as the concentration of trace metals likezinc, cupper, cadmium, lead and chromium were very high and were the major pollutants.
    Full-text · Article · Dec 2010 · International journal of Environmental Science and Technology
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    • "serves as a means of livelihood in terms of fishing activities (Agbozu et al., 2007 "
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    ABSTRACT: Concentrations of Fe, Pb, Cr, Ni and V were measured in sediments taken from eight (8) sampling stations along a section of Kolo creek which traverses an oil flow station and a point in Epie creek which receive effluent discharges from human and industrial activities. The study was conducted in four seasons (Dry, Late Dry, Rainy and Late Rainy Seasons). Vanadium was less than 0.001 mg/Kg in all the samples analysed. Fe, Pd, Cr and Ni had annual means of 5109.85, 1.60, 14.22 and 10.18 mg/Kg respectively. One way ANOVA at 95% confidence limit showed no significant difference in the nine (9) sampling stations. However, there was significant difference in the four (4) seasons that the study was conducted. Cluster analysis of the data further classified the four seasons into two groups. Geoaccumulation indices showed that the Creek is not polluted by Pb, Cr and Ni, however, it is highly polluted with Fe. The highest positive correlation was between Pb and Cr while the highest negative correlation was between Fe and Ni. Compared to DPR intervention values, Kolo creek is free from pollution by Pb, Cr and Ni.
    Full-text · Article · Oct 2010
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    • "Also, crude oil pollution influences plant root development (Ekpo, 2002), soil water absorption by plants (Atuanya, 1987), biotoxicity (Atuanya, 1987), soil structure, water stress and nutrients deficiencies (Odjegba and Sadig, 2002; Gil et al, 2003) and decline in crop performance (Gaskin et al, 2007). Heavy metals associated with crude oil spillage are naturally found in soils (Ojanuga et al, 1996), but monitoring is necessary for understanding metal load (Odu et al, 1996) as elevated accumulation has direct consequences to man and ecosystem (Agbozu et al, 2007). Treataility of soils affected by crude oil spillage depends not only on soil characteristics, but on type, availability and affordability of remediation techniques (Ram et al, 1993). "
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    ABSTRACT: We investigated characteristics of crude oil-contaminated soils of a town within an oil-exploration zone of southeastern Nigeria in 2006. Target sampling technique was used in collecting soil samples, which were later prepared for various laboratory analyses. Cassava sludge was obtained from wastewater disposal pit and composted using Aerated Pile meth-od. Five temporal treatments, namely 30, 60, 90, 150 and 180 days were observed when 0.5 kg composed Cassava sludge was applied on 5-kg soil set up in a completely randomized design. Results showed differences in chemical composition of sludge and its compost. There were significant (P = 0.05) variation in the removability of priority pollutants using composted Cassava sludge: with greater efficacy at 120 and 180 days for total cadmium and nickel. Further studies should consider varying rates of this sludge and different soils since soils of the area are formed from dissimilar lithologies. [Life Science Journal. 2008; 5(3): 62 – 66] (ISSN: 1097 – 8135).
    Preview · Article · Jan 2008 · Life Science Journal
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