Assessment of some Micro-Organisms and Physico-Chemical Properties of Floodwaters in some major Streets in Benin City, Nigeria

Abstract

This paper investigated microorganisms and physico-chemical properties of floodwaters in some major streets in Benin City. Floodwater samples were collected from the selected streets and taken to the laboratory for analysis using AAS Model-Solaar 969 Unicam series with Air Acetylene flame. The increasing trends of annual and October rainfall justified the timing of this study. Samples revealed colour (CTU) value of >550 in Ugbowo-Lagos Road, New Benin-Ugbowo Road and Textile Mill Road while the lowest value was recorded for Siluko Road. The highest PH at room temperature was recorded in Siluko Road (6.90) and lowest in New Benin-Ugbowo Road (8.70) while conductivity (μs/cm) was highest in New Benin-Ugbowo Road (519) and lowest in Siluko Road (203). While the highest Cl^-1 (mg/l) was recorded against Ugbowo-Lagos Road (141.65), Textile Mill Road revealed the lowest value (33.02). The highest and lowest dissolved CO₄ (mg/l) were recorded against Ugbowo-Lagos Road (51.64) and Textile Mill Road (8.80) respectively. Similarly, Fe (mg/l) was highest in Ugbowo-Lagos Road (4.39) and lowest in Textile Mill Road (0.15). Only the relationship between Cl-1and conductivity was significant (P < 0.05).Aerobic mesophilic count of the samples were highest in Upper Mission Road (5 x 10⁴ cfu/ml) and lowest in Ugbowo-Lagos Road (2 x 10³ cfu/ml) while coliforms were highest and equal in Siluko, Textile Mill and Upper Mission Roads with at (4 x 10³ cfu/ml) and lowest in Ugbowo-Lagos Road (2.3 x 103 cfu/ml). With the exception of Siluko Road with a value of (2 x 10² cfu/ml), no trace of Escherichia. coli was found in samples collected from other roads. Similarly, no traces of Enterococus and yeast/fungi were detected in all the samples. It is concluded that the physico-chemical conditions of floodwaters may have contributed to vehicular corrodibility while the Aerobic mesophilic and Coliforms states of floodwaters could pose health risks to pedestrians. It is recommended that the on-going urban renewal should make provisions for drainage and in the interim, motorists and pedestrians should avoid contacts with floodwaters to reduce corrosion of the metallic components of their vehicles and health hazards.

Keywords: Rainfall dynamics, floodwater, physico-chemical properties, micro-organisms and Benin City