Seasonal Changes in Microbial Density and Diversity of Ikpoba River Water Samples in Benin City Nigeria

Akpe Azuka Romanus

doi:10.11648/j.ijmb.20180302.12

Abstract

River water is a major source of water for household use in most rural communities in Nigeria. River pollution refers to the contaminations of rivers which occur when waste and different other pollutants are discharged into river without being properly treated. Studies on river water pollution and their implication to public health has been ongoing. An assessment of the seasonal changes in microbial density and diversity of Ikpoba River in Benin City, Nigeria was carried out between the months of January to March and May to July 2017 for the dry and wet seasons. Standard microbiological procedures were used for the study. Results showed that the density of the microbial isolates was highest during the dry season. There is significant difference (P>0.05) in the heterotrophic microbial counts in both seasons. The discharge point, upstream and downstream bacterial counts for dry season ranged from 1.5±0.00 x 104cfu/ml to 4.0±0.23 x 106cfu/ml whereas the wet season samples had lower counts ranging from 2.0±0.05 x 103cfu/ml to 4.0±0.21 x 104cfu/ml. Similarly, the fungi counts for the dry season ranged from 6.0±0.01 x 102cfu/ml to 1.4±0.53 x 106cfu/ml while for the wet season it ranged from 5.0±0.00 x 102cfu/ml to 9.0±0.32 x 104cfu/ml. The highest counts were at the point of discharge while the lowest counts were recorded for the upstream samples. The diversity of the microbial species was more in the wet season than in the dry season. The bacteria isolated during the dry season were Salmonella sp, E. coli, and Vibrio sp. In the wet season the isolates included E. coli, Salmonella sp, Vibrio sp, Staphylococcus aureus, and Streptococcus faecalis. The wet season fungi isolates were Aspergillus fumigatus, Aspergillus niger, species of Penicillium and Rhizopus while the dry season isolates included Aspergillus fumigatus, Aspergillus niger and species of Penicillium. The microbial density is higher in the dry season and lower in the wet season while there are more microbial diversities in the wet season than in the dry season.

Highlights

There are various forms of industrial wastes that interfere with the quality of life of all living creatures and with the earth’s ecological system
The research has shown that brewery effluent is the major culprit responsible for the pollution of Ikpoba River
The high microbial density obtained during the dry season was occasioned by the continuous discharged of effluent into the river by the Brewery coupled with the reduction in the volume and water current thereby making the water more settled for microbial proliferation, pollution more pronounced and the odorous effect more felt

Summary

Introduction

There are various forms of industrial wastes that interfere with the quality of life of all living creatures and with the earth’s ecological system Some of these industrial wastes if allowed into the environment cause environmental pollution [1]. Some of the pollution enriches the water body with nutrients leading to growth of algae and other phyto-plankton which shade or clog the water surface, making it anoxic. When this pollution reaches the highest level, the oxygen concentration of the bottom of the stream become zero, a zone of putrefaction will occur with the production of hydrogen sulphide (H2S), ammonia (NH3 ) and other odorous gases leading to the death of many fish species and other aquatic organisms [3]

Methods

Results

Conclusion