Spatial and Seasonal Variation in the Contamination Indices of Trace Metals in Sediment from Qua Iboe River Estuary, South-South, Nigeria

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Author(s) Moses, E. A. | Etuk, B. A. | Udosen, E. D.
Pages 507-517
Volume 4
Issue 11
Date November, 2015
Keywords Trace Metals; Contamination Indices; Sediment; Qua Iboe River Estuary.
Abstract

This study was conducted to determine the levels of trace metals in sediments from Qua Iboe river estuary(QIRE), Nigeria and assess their extent of contamination. Sediment samples were collected from five designated stations and one reference station along QIRE in the dry and wet seasons and analysed for trace metals using atomic absorption spectrophotometer. Geo-accumulation indices, enrichment factors, pollution load indices, degree of contamination and contamination factors were estimated using suitable models. Concentration of metals in mg/kg during the dry season were: Pb (0.03-4.57), Cd (0.04-0.65), V (0.03-0.58), Cr (1.54-3.69), Ni (1.74-5.18), Fe (23.60-41.87), Zn (7.20-14.52). The ranges for the wet season were Pb (0.10-1.65), Cd (0.06-0.53),V (0.04-1.75), Cr(0.31-2.89), Ni (1.18-5.37), Fe(27.04-31.87), Zn (5.03-14.93). Levels of trace metals investigated were below the sediment quality guidelines except Fe. Contamination indices revealed that the sediments from Qua Iboe river estuary were contaminated with respect to the indices considered in this study. Enrichment factors and geo-accumulation indices indicated anthropogenic sources of pollution especially for Pb, Cd and V. There is need for regular monitoring of the aquatic ecosystem to minimize sediment contamination which may pose ecological risk to benthic and pelagic organisms.

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