Seasonal Variation of Cd, Ni, Cu and Pb in Catfish, Sediment and Water Samples from Ipo Stream in Ikwerre District of Rivers State, Nigeria

The variation of some heavy metals Cd, Ni, Cu and Pb was conducted on sediment, cat fish and water samples from four stations in Ipo stream in dry and wet seasons. Atomic Absorption Spectrophotometry model 3700 was used to analyzed the samples The result revealed that the average metal concentrations in sediment in both seasons was in the order Pb > Cu >Ni > Cd which were 25.73μg/g, 18.48μg/g, 2.91μg/g and 1.35μg/g respectively. In fish sample the metals also occurred in the order Pb ,Cu , Ni and Cd which were 24.14μg/g ,17.85μg/g, 2.79μg/g and1.15μg/g respectively, while in the water sample similar trend of heavy metals concentrations also occurred which were 23.32μg/l for Pb,17.32μg/l for Cu, 2.42μg/l Ni and1.15μg/l for Cd respectively. These values were below the established standard for aquatic environment by W.H.O and FAO. The result indicated that the consumer of fish and water from the stream is not at risk of being poison by these metals. @ JASEM The distribution and partitioning of heavy metals in ambient water system had been conducted world wide. Heavy metals have been known to be distributed to the environment as a result of natural and human processes. Wittman, 1979 and Robinson, 1996 identified causes of heavy metal pollution of river system to include complex industrials processes, mining, agricultural practice, leaching of metal from garbage dump, domestic waste, atmospheric precipitation and discharge of petroleum products to the environment. Various environmental factors like temperature, pH, water hardness, dissolved oxygen, light, salinity and organic matter can influence the toxicity of metals in aquatic medium (Bryan, 1971).Freshwater have been known to exhibit a high natural variability in their physical and chemical properties due to local differences in geology and climate. They are therefore more susceptible to anthropogenic influence than the marine environment (Rainbow and Dallinger 1993). The main pathway to human contamination by organic and inorganic pollutants associated to aquatic system is the consumption of contaminated food(Mackey,1991).Aquatic organisms tend to concentrate trace metal to a high magnitude and man is the ultimate consume of these aquatic organisms. Foran (1990) reported that the potential human health associated to the consumption of contaminated food is 20 to 40 times higher than the ingestion of contaminated water. This is due to the capacity of some aquatic organisms to concentrate heavy metals such as Fe, Cu, Zn etc. up to 10 times the concentration present in the water (Gillimarães et al, 1985).These heavy metals are generally considered to be less toxic than non-essential metals (Bartley,1983).They are toxic when present in elevated concentration in the environment (Bryan,1971, Du Preez and Van Vuren,1994; and Sander, 1997).It is important to monitor pollution levels of heavy metals in aquatic system carefully so that approximate measures of the potential hazard can be attained. These measures should give an estimation of the type of effect that could be expected after exposure of heavy metals. In Nigeria, studies have been conducted on both fresh and brackish water fish to determine the levels of heavy metals. Kakulu et al, 1987,Obasohen and Okonsaye, 2004 have evaluated concentrations of heavy metals in Nigerian rivers where they reported levels of cadmium as follows 0.074mg/kg to 0.13mg/kg for Oreochromics niloticus, 0.07mg/kg to 0.15mg/kg for Hemichronis fasciatus. While in USA Low et al, 1978 found freshwater fish collected from rivers to contain cadmium as follows in 1978 0.41ppm ,in 1979 0.41ppm in 1980 0.03ppm and in 1981 0.35ppm, on the other hand lead detected had a mean concentration of 0.19ppm in 1978, 0.16 in 1979 and 0.17ppm in 1980 and 1981 respectively. The main purpose of this paper was to evaluate the concentration of Cd, Ni, Cu and Pb in different matrix of Ipo stream which include sediment, water and cat fish to determine their pollution status. MATERIALS AND METHODS Description of the study area Ipo stream is located in Ipo community in Ikwerre district of Rivers State situated in Niger Delta area of Nigeria. The Niger Delta area lies between latitude 4o 15 ́N and 6o 30 ́N and longitude 5o 00 ́E and 8o 00 ́E.The area falls within the tropical rainforest which normally experienced two seasons yearly which are the dry and wet seasons. The dry season normally starts from November to April, while wet season starts from May to October. The annual rainfall is usually about 2106mm.The Ipo stream occupies an area of about 850m per square area and is located about 3 kilometers from Port Harcourt Seasonal Variation of Cd, Ni, Cu and Pb in Catfish, Sediment and Water Samples from Ipo Stream in Ikwerre District of Rivers ....... * Corresponding author: Kpee, Friday 64 International airport Omuagwa. The stream receives domestic, industrials effluent, air burn particulate matter and storm water runoff from the immediate environment. The sediment of this stream has been developed from sand, dead leaves and organic black silt that are affected intensively by exploration activities. In the early 1990’s the inhabitants of Ipo community rely solely upon water and fish from the stream for their survival.