Effects of seasonal variation and locations on microbial load in sediment and water of a polluted ecosystem

Seasonal effects on microbial load of sediment and water at different locations along Bonny Estuary of Niger Delta was investigated for a period of 12 months. All analyses followed standard procedure. Results revealed that total fungi counts in sediment and water at different locations were not significantly different (p > 0.05) at both wet and dry seasons while hydrocarbon utilizing fungi showed significant differences (p < 0.05) at both seasons in both sediment and water samples. During the wet season, total faecal counts ranged from 5.0 to 10.0 x 105 CFU/g for sediment and 4.0 to 7.0x 105 CFU/g in water. In dry season, the concentration of hydrocarbon utilizing bacteria in the sediment ranged between 0.1 x 105 CFU/ml/g and 8.0 x 105 CFU/ml/g in wet season while in dry season, the concentration in water ranged between 0.1 x 105 CFU/ml/g and 6.0 x 105 CFU/ml/g at Abuloma. At Okwujagu, total heterotrophic bacteria counts in sediment ranged  from 0.1 to 8.0 x 105 CFU/g in dry season. This was higher than the range 0.1 to 6.8.0 x 105 CFU/ recorded in Abuloma, Okwujagu and Slaughter at dry season. The highest vibrio counts in water (11.0 x 105 CFU/ml) for wet and (10.0 x 105 CFU/ml) for dry seasons were recorded at Slaughter. In Oginiba, the feacal count recorded 3.0 x 105 CFU/ml in water during the wet season and 2.0 x 105 CFU/ml for dry season. Generally, there were significant differences (p < 0.05) in the bacterial concentrations in both sediment and water. This showed that different seasons favour the growth of certain microbial types

Effect of depuration on heavy metal concentrations in periwinkle (Tympanatonus fuscastus) from a polluted creek in Rivers State, Nigeria

The efficiency of depuration in the removal of heavy metals in Periwinkle (Tympanatonus fuscastus) was evaluated in this study. Periwinkle in depuration tanks were taken at intervals of 24, 48, 72 and 96 hours of depuration and analyzed for these heavy metals: Lead (Pb), Zinc (Zn), Chromium (Cr) and Cadmium (Cd). Results from the analyses shows that time, method and season has significant effect on heavy metals. At different location, there was significant difference at different time interval of depuration for both seasons. The control for all the locations had the highest count for depuration at both seasons. The concentration of Pb, Cr, Cd and Zn for depurated periwinkle at 24-96 hours was significantly different (P<0.05) from control for both rainy and dry season. Notably, at 96hours of depuration, these metals were reduced. The depuration of these contaminants on the shellfish was faster during rainy season than dry seasons brought about satisfactory results. This study depuration method at the different time intervals is suggested.Keywords: Heavy metals, purification, processing, pollutants, Tympanatonus fuscastu