Bacteriological water quality of Elechi creek in Port Harcourt, Nigeria

Abstract

The bacteriological quality of Elechi creek was investigated during a seven-month sampling period. Samples were collected from seven stations grouped into zones A, B and C. The study revealed uniformity in the range of temperatures (which ranged from 28° to 32°C) in all the stations of the zones. The pH values obtained for all the stations ranged from 6.5 to 7.7 and were within the acceptable ranges for brackish water such as the study area. The BOD values for stations of zone B ranged from 3.92 to 8.80mg l-1 while those of zones A and C ranged from 2.07 to 3.86 mgl-1 and 1.43 to 3.46 mgl-1 respectively. The reverse was the case for DO values, which were lower in stations of zones B than those of zones A and C. The results for oil and grease values for all the stations of the zones showed a range of 0.09 to 1.22 ppm which were far lower than the permissible limit for industrial effluent samples. The minimal values suggested absence of petroleum activities in the area. The results of the bacterial counts for the Elechi creek showed that total aerobic heterotrophic bacteria ranged from 0.12 x 106 to 2.81 x 106 cfuml-1, total coliform bacteria ranged from 0.06 x 105 to 2.00 x 105 cfuml-1 and hydrocarbon-utilizing bacteria ranged from 2.0 x 102 to 10.0 x 102 cfuml-1. The bacterial genera isolated from the Elechi creek included Aeromonas, Bacillus, Citrobacter, Corynebacterium, Pseudomonas, Enterobacter, Escherichia, Flavobacterium, Klebsiella, Micrococcus, Proteus, Staphylococcus, Enterococcus, and Vibrio species. Of the organisms isolated only Bacillus, Corynebacterium, Pseudomonas and Flavobacterium species occurred in all the stations of the zones while the others occurred in one or more stations and not in others station. The varying mean counts of bacteria and the occurrence of bacterial species the creek, brought to consideration, the possible influence and sources of contamination around each zone. The observed high coliform counts and the presence of Escherichia coli was sufficient to suspect the contamination of the water body with pathogenic bacteria; hence the water is of low quality and should not be used for human consumption. The low counts of hydrocarbon-utilizing bacteria confirmed absence of a possible source of contamination of the creek by crude oil and its products. Journal of Applied Sciences and Environmental Management Vol. 9(1) 2005: 79-84