Spatial Analysis of heavy metals Concentration around the Lagos Lagoon, Nigeria
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Environmental and Social Sciences, Ahmadu Bello University, Zaria, Nigeria
An analysis of the concentration of 8 heavy metals - Lead (Pb), Arsenic (As), Iron (Fe), Cadmium (Cd), Zinc (Zn), Manganese (Mn), Copper (Cu) and Chromium (Cr) in the bottom sediments of Lagos Lagoon was carried out using an AAS and the result interpreted using Geographical Information System (GIS) tools. The kriging and Inverse Distance Weighed (IDW) technique was used to perform the interpretation of the results with a view to quantify the spatial variability and generate the Metals Risk Maps for each of the metal and all the metals as a whole over the region. The results were compared with the Nigerian Standard for Drinking Water Quality (NSDWQ, 2007) drinking water quality standard. The findings revealed that Mn recorded highest concentrations of 225.9mg/l and 336.5mg/l for dry and rainy seasons respectively around Egbin (A9); Cd recorded highest concentrations of 19.6mg/l for dry season at Tincan creek (A12) and 90.3mg/l for rainy season at Commodore Channel (A10); As recorded highest concentrations of 70.5mg/l and 90.3mg/l for dry and rainy seasons respectively around Tincan creek (A12); Pb had highest concentrations of 28.6mg/l and 41.9mg/l for dry and rainy seasons respectively around Apapa (A11). Cr highest concentrations of 14.0mg/l and 19.7mg/l was recorded around Apapa (A11) for dry and rainy seasons respectively; Cu has concentrations of 22.6mg/l and 24.0mg/l around Okobaba (A4) and Oworoshoki (A7) for dry and rainy seasons respectively; Fe recorded highest concentrations of 3,093mg/l and 2,146mg/l for dry and rainy seasons around Egbin (A9) and Oworoshoki (A7) while Zn recorded highest concentration of 29.7mg/l and 35.2mg/l at Commodore Channel for dry and rainy seasons respectively. It was observed that the concentrations of all the parameters analysed were above the NSDWQ (2007) drinking water standard limit while Cu and Zn are within tolerable limits. The findings also revealed that locations around Tincan Creek, Commodore Channel, Apapa, Five Cowries, Ijora, Iddo towards the south-eastern part of Lagos Lagoon are at higher risks than the Mid-Lagoon and Egbin axis in the north. The factors responsible for the contaminants were identified as sand mining and dredging, urban domestic wastes and sewerages, industrial wastes.
Heavy metals , Lagos lagoon , bottom sediments , spatial analysis , Research Subject Categories::SOCIAL SCIENCES
Soneye, A. S. O., O. A. Abiodun and A. O. Ayeni (2018). Spatial Analysis of heavy metals Concentration around the Lagos Lagoon, Nigeria, Savanna Journal, 24 (2): 106-115