A STUDY OF THE PHYSICO-CHEMICAL PARAMETERS AND HEAVY METAL CONCENTRATION IN WATER AND SEDIMENT OF OGBE-IJOH WATERSIDE OF WARRI RIVER
A study of the physico-chemical parameters and heavy metals contamination in water and sediments of Ogbe-Ijoh waterside of Warri river, Delta state, Nigeria was carried out between February and July 2013. All samples were taken from three different points along the river. The physico-chemical parameters of the water samples were measured both in-situ and in the laboratory. The parameters measured included air and water temperature, pH, biological oxygen demand (BOD5), dissolved oxygen (DO1), chemical oxygen demand (COD), electrical conductivity (EC), transparency, total dissolved solids (TDS), alkalinity, ammonium-nitrogen (NH3-N), chloride, sulphate, nitrate, phosphate, sodium, potassium, calcium and magnesium. The range values of the measured parameters were compared with World Health Organisation (WHO) and Federal Environmental Protection Agency (FEPA) standards. The findings showed that all the physico-chemical parameters measured were within the tolerable value ranges except pH, Chemical Oxygen Demand (COD) and phosphates (PO43-). The pH of the water was found to be between 5.49 to 7.98; showing a moderately acidic to neutral condition in the study area as opposed to WHO (7.0 – 8.5) and FEPA (6.00 – 9.00) limits. COD exceeded WHO and FEPA limits (10mg/l) with the range values of 7.60-71.92mg/l while phosphates with range values between 0.18 – 0.90mg/l exceeded WHO (0.26mg/l) and FEPA (0.50mg/l) limits. The results from the heavy metals (Cd, Ni, Mn, Cr, Pb and Hg) assessed for both water and sediments showed that Cd, Ni, Mn and Cr were not detected in the water but were detected in the sediments; however, Hg was detected in neither water nor sediment. The mean concentration of metals in water were 0.25±0.38mg/l (Cr) and 0.13±0.06mg/l (Pb), and mean concentration of metals in sediment were 4.13±2.06mg/kg (Cd), 107.90±16.08mg/kg (Mn), 2.08±0.63mg/kg (Ni), 1.61±0.52mg/kg (Cr) and 72.03±11.2mg/kg (Pb). These values exceeded WHO and FEPA limits thus suggesting thatthe water is unfit for consumption, therefore, frequent monitoring of physico-chemical parameters of Ogbe-Ijoh waterside of Warri river is imperative.
1.1 Background to the Study
Water is a finite resource that is very essential for the human existence, agriculture and industry thus, inadequate quantity and quality of water have serious impact on sustainable development. In developing countries such as Nigeria, people have little or no option but to accept water sources of doubtful quality, due to lack of better alternative sources or due to economic and technological constraints to treat the available water adequately before use (Calamari and Naeve, 1994; Aina and Adedipe, 1996). The scarcity of clean water and pollution of fresh water has therefore led to a situation in which one-fifth of the urban dwellers in developing countries and three-quarter of their rural dwelling population do not have access to reasonably safe water supplies (Lloyd and Helmer, 1992).
Water quality characteristics of aquatic environment arise from a multitude of physical, chemical and biological interactions. A regular monitoring of water bodies with required number of parameters in relation to water quality prevents the outbreak of diseases and occurrence of hazards. According to Wotton (1992), material pollution of rivers is caused by toxic pollutants (heavy metals, phenols and insecticides, among others) that have direct adverse effect on aquatic biota and by-pollutants (human and animal waste) that indirectly affect aquatic biota, which are not toxic but due to bacterial action on them, dissolved oxygen is used up which harms aquatic biota. Assessment of water is not only for suitability for human consumption but also in relation to its agricultural, industrial, recreational, commercial uses and for its ability to sustain aquatic life. Water quality monitoring is therefore a fundamental tool in the management of freshwater resources.
The biotic component of the aquatic ecosystem, which consists of fauna and flora, are indispensable economic resources. Major components of aquatic fauna are the finfish and shellfish (shrimps, prawns, crabs, lobsters, clams, scallops, periwinkles and oysters among others). Rural artisans who depend on fisheries as a means of livelihood concentrate on shallow water bodies like rivers, creeks, lakes and lagoons for their fishing expedition; this is due to their inability to explore larger water bodies because of limited capital. In Nigeria, the artisanal fisheries sector produces bulk of fish consumed by the populace; in addition, this fisheries sector provides income, employment, raw materials and foreign exchange to the Nigerian populace and the nation (Kumolu-Johnson, 2004).
However, in recent times, Nigeria inland water bodies have been subjected to various forms of degradation due to pollution arising from domestic wastes, industrial effluent, agricultural run-offs, oil spillage, mine effluents and obnoxious fishing practices (Ndimele, 2008). The result is that the associated fishery, the biota and the ecosystem upon which fishers depend for a living are destroyed and consumption of fish caught from such polluted water bodies poses severe danger to the consumers (Kumolu-Johnson et al., 2005). One of such pollutants is heavy metals.