ABSTRACT

Water, sediment and shellfish were collected from four locations (Slaughter, Aboluma, Okwujiagu and Oginiba) of the Azobie creek of River state Nigeria and were evaluated for microbiological, heavy metals, nutritional composition and physico-chemical parameters. Bacterial isolates consisting of  ( total  heterotrophic bacteria and hydrocarbon utilizing bacteria count)  and fungal count (total fungal count and hydrocarbon utilizing fungi count) were analysed from the shellfish and  its habitant (water and sediments). Data generated were subjected to analysis of variance (ANOVA) and mean were separated using fishers minitab 2017. The highest total coliform counts obtained from  Slaughter (control) had a value of 1.52 during wet season and 1.23x10⁵ CFU/g in dry season and in Aboloma it was 1.53x10⁵CFU/g for wet season and 1.12x10⁵ Cfu/g for dry season in periwinkle . These  decreased to an acceptable limit of 0.02 x10 ⁵CFU/g at different time intervals of 24-96h of soaking and depuration. Total heterotrophic bacteria count in periwinkle had the highest count in control at Slaughter, Oginigba and Abuloma at a value of 0.48 and 0.33X10⁵ CFU/g This was reduced to acceptable limit of 0.12 x 10⁵ CFU/g. Similar trend occurred in oyster sample at the same locations. Total hydrocarbon utilizing bacteria and fungal count in oyster had the highest count of 9.80 during wet season and 8.90x10⁵ CFU/g for dry seasons at Slaughter and Abuloma at 9.17x10 CFU/g for wet season and 7.12x10⁵ CFU/g during dry season. Oginigba did not record any bacteria count. Total faecal  count was reduced at different time interval of 24-96h to an acceptable limit , while for depurated at different time intervals during dry season, it was not reduced. This could be as a result of the different depuration methods. The same trend was observed in periwinkle although it was not fast as in oyster. The different bacterial profiles are probably attributable to industrial activities of the sites. The moisture, protein, fat, crude fiber and ash content were the major constituents which had been considered in evaluating the nutritional value of these species. Soaking  shellfish had no effect on the proximate composition except in fat where it increased  the fat and protein content in the control. Physio chemical parameters varied among different locations. The levels of Cd ( 0.00-2.5ppm) recorded in these samples were higher than the maximum recommended limit of 2-0ppm in sea food. The value of Cr recorded was between 1.50 – 2.0 ppm and was found to be higher than the maximum recommended limits of 0.15-1.0ppm.The levels of Pb (0.001-2.50) recorded in this study was higher than the recommended limits of 2.0ppm  in some locations. The micro nutrient (K, Fe, and Zn) were above the permissible limits for human consumption as recorded by the Food and Agricultural Organization. Depuration had little effect on  contaminant while soaking had no effect at different locations and different time intervals. Depuration performed