Microbiological properties of water and sediment of New Calabar River, Port Harcourt, Nigeria

Abstract

Microbiological characteristics of water and sediment of New Calabar, River, Port Harcourt, Nigeria were investigated. Water and sediment samples were collected from three stations {Aluu, ARAC (Station 1; Choba Bridge (Station 2) and Rumuokparali (Station 3)} on a monthly basis between February and April, 2020 and analyzed using standard methods. The results showed that Total Heterotrophic Bacteria in water (THBw) ranged between 2.20 x 10² and 2.6x104 cfu/ml with the overall mean value of 7,313.33 + 1039.09 cfu/ml while that of sediment (THBs) ranged between 3.1 x 10³ and 3.9 x 10⁴ cfu/g with the overall mean value of 42,566.67 + 71199cfu /g. The THB counts were higher in sediment than in water with Station 2 significantly different from other stations. Total Coliform Bacteria (TCB) in water ranged between 1.1 x 10³ cfu/ml and 2.9 x 10³ cfu/ml with the mean value of 1988.89±532.55cfu/ml while that of sediment ranged between 1.3 x 10³ cfu/g and 2.5 x 10⁴ cfu/g with the mean value of 9422.22 ±9595.41cfu/g. TCB counts in water showed no significant difference across the stations at p<0.05 but Station 2 statistically differed from Stations 1 and 3 in the sediment. Morphological and biochemical tests showed that 8 bacteria species were isolated from sediment and and 9 specimens were recovered from water. Some isolated specimens were: Bacillus spp, Staphylococcus. sp, Bacillus cereus and Bacillus subtilis while Escherichia coli was the only bacterium found in water but absent in sediment. Two species: Staphylococcus spp and Bacillus subtilis dominated the study area. Fungal counts in water ranged between 3.0 x10² and 2.6 x 10³ cfu/ml with the overall mean value of 1911.11±67.51cfu/ml while that of sediment ranged between 1.7 x10¹ and 3x10² with the overall mean value of 173.00±78.52 cfu/g. Fungi counts showed significant difference (p < 0.05) across the stations in water and sediment. Macroscopic and microscopic characterization of fungi showed that 6 fungi species were recovered in water and sediment. These included Aspergillus niger, Rhizopus oligospora and Pennicillium species. The species Fusarium solani and Aspergillus flavor were found in Station 1 but absent in Stations 2 and 3. It could be observed that microbial counts in both water and sediment exceeded the 1.0x10² cfu/ml and 0 cfu/ml recommended levels by WHO and EPA respectively. Thus, the study area may be under threat and the water may be unsafe for human consumption.

Keywords: Microbiological Properties, Sediment, Water, New Calabar River, Port Harcourt