ABSTRACT
Over 90% of the world's goods are transported by Sea. Ships transport around 10 billion gallons of ballast water internationally each year in order to carry goods, and an estimated 7000 marine and coastal species are stowed away daily in the process to a new clime. Ballast water is the water used by ships to maintain balance when cargo is discharged and to attain the proper immersion level. Onne is a multipurpose cargo port involving fishing, Oil and Gas exploration, and, free trade zone. Between 2012 and 2017, it accounted for 80% of Nigerian exports, according to figures from the Nigerian Ports Authority. The cargo and ballast water, either separately or together, offer a safe immersion level for the ship's propulsion and mobility. Microorganisms such as bacteria, protists, protozoa, algae, zooplankton, faecal coliform, benthonic invertebrates, and fishes are commonly found in ballast water that could influence the aesthetic components of the receiving water. This research project was therefore carried out to evaluating the physicochemical and bacteriological qualities of ballast waters on the receiving of water bodies of Onne Sea Port.
At Onne Sea Port in Rivers State, Nigeria, water and sediment samples were collected at five (5) different specified locations adjacent to Ship anchorage positions, on a monthly basis for a period of one year between April, 2017 and March 2018. Water and sediment samples were analyzed for physicochemical composition, as well as temporal and geographical variability. The total number of heterotrophic bacteria was determined using a conventional technique. The bacterial isolates were also identified molecularly utilizing PCR amplification and sequencing analysis DNA extraction, PCR amplification, and sequence analysis were used to determine characterization at the molecular level. Amplification of the small ribosomal subunit gene (16S r DNA) was performed using eubacterial universal primers P27f and P 1495r, which referred to the E. coli nucleotide sequence of the 16S r DNA gene. The antimicrobial susceptibility of the isolates was evaluated using the Kirby-Bauer method and the disk diffusion test. Using a conventional approach, the water quality index was calculated for wet and dry season water samples. The results were reported as the average of three replications. Because the water samples were gathered from diverse sites and the conditions in which they were collected were not controlled, a 2 ways analysis of variance was adopted.
The results showed that there were significant temporal and spatial variations in the physicochemical parameters of the water sample obtained, with greater values reported during the month of August, when the record of ship docking was highest. The study found significant temporal and regional variation in total heterotrophic bacterial counts (THBC). The highest count was in August, with THBC ranging from 8.2 to 14.1 x 106 cfu/l. Bacilli, such as Bacillus subtilis, Bacillus pumilus, Bacillus cereus, Bacillus pacificus, and Bacillus amyloliquefaciens, made up the majority of the bacterial isolates from water samples; other isolates included Propionimicrobium lymphophilum, Pseudomonas parafulva, Methanocaldococcus fervens, and Enterobacter aerogenes. All of the bacterial isolates were resistant to Augmentin, Nitrofurantoin Ciprofloxacin, Cetazidime, Gentamicin, Cefixime, and Cefuroxime; nevertheless, they were mostly responsive to Ofloxacin. It was determined that the water was unsafe for consumption based on the computed water quality index of 5614.91 during the dry season and 5615.27 during the wet season, both of which were higher than the World Health Organization water quality index standard of 100. The presence of coliform bacteria as well as positive Shigella counts throughout the year further corroborated this. Microorganisms have a high probability of become invasive species if discharged as ballast water and can have serious ecological, economic and public health impact on the receiving environment. The study inferred that the isolate harbour bacteria species of health importance and which were multidrug resistance to a number of antibiotics. The outcome of this study consequently given data needed for quality assurance for the user of marine resources that were practicing aquaculture and fisheries.
