Journal de chimie analytique environnementale

Environmental Implications and Significance of Rainwater Harvested from Lagos, Southwest Nigeria

Abstract

Uzomaka C Okpoebo, Titilope J Jayeoye, Alaba J Adebayo and Ilemobayo I Oguntimehin

This study assessed heavy metals and some physicochemical properties in rainwater harvested from Lagos, Nigeria. Rainwater was collected from three different locations using varying collectors from the months of April to July, 2013. Physicochemical parameters like pH, temperature, electrical conductivity (EC) and few heavy metals were assessed. Eight Heavy metals were determined by Flame Atomic Absorption Spectrophotometer (AAS). pH (5.1 to 7.6), Temperature (23.0 to 27.2Ë�C), EC (648 to 894 μS/cm ) is lower than the 1000 μS/cm limit by WHO. Mn and Cr were below the detection limits of the instrument. Ni, Pb and As were about 20 to 40 times higher in the rooftop samples and controls above the recommendation of standard organizations. Fe, Ca and Zn were detected but not believed to be of much environmental threats in all the study locations. The quadratic pattern was generated for the interaction between average monthly precipitation and heavy metal contents. Strong relationships were signaled by high R2 value from the best fitting lines. The study suggests that rainwater consumption in all the study locations irrespective of the collector type or method may result in severe health hazards associated with overexposure to the three notorious heavy metals. It is concluded therefore that metal concentrations particularly of Ni, Pb and Asis an important issue which must be addressed in the task of considering rainwater as reliable water complement drive.