Assessment of Physicochemical and Heavy Metal Concentrations of Surface Water in Creeks adjoining Lagos Lagoon, Nigeria

Abstract

Creeks are potential contamination sinks for heavy metals and pollutants released from domestic, industrial, and other anthropogenic activities. This study assessed the physicochemical characteristics and heavy metal concentrations of surface water of some creeks adjoining Lagos Lagoon, Nigeria. Water samples were collected monthly from three creeks (AbuleAgege, AbuleEledu, and Ogbe) between June and November 2016 within 25cm depth, using hydrobios water sampler and analyzed for pH, Temperature, Conductivity, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Sulphate, Phosphate, Nitrate, Calcium, Iron (Fe), Zinc (Zn), and Lead (Pb); all determined in triplicates. The results revealed that all the physicochemical parameters determined is significant (P<0.05) except temperature, TSS and sulphate which showed no significant difference (P>0.05)across the three sampling stations. The physicochemical parameters and study months showed a significant interaction (P<0.05)for COD in June, August, and October. The parameters studied were within the limits of USEPA and WHO except for DO (1.6-3.8mg/l) which was lower than the WHO recommended 5mg/1 for water quality assessment and Ogbe creek that recorded BOD values >30mg/l from September to November thus depicting a deteriorating creek. The concentrations of Zn, Fe and Pb in the water samples were within the safe limit, but pose potential human and fisheries health implications from continuous usage. The varying concentrations in the creeks were as a result of unregulated anthropogenic activities. Innovative and cost-effective waste management practices are essential to be incorporated into the residential and industrial waste disposal system to curtail the water contamination.