ABSTRACT. The distribution of some heavy metals, namely Cu, Pb, Zn, and Fe in sediments of Fosu lagoon of Cape Coast, Ghana was studied in the early summer (November) of 2009. The levels of the selected trace metals were determined using atomic absorption spectrophotometry. The overall mean ± RSD % of Cu, Pb, Zn, and Fe were, respectively 26.4 ± 51.0, 28.1 ± 101.0, 20.90 ± 41.90 and 1.15 × 10 3 ± 2.02 mg/kg. Fe recorded the highest concentration levels, the distribution of which followed the sequence Fe > Pb > Cu > Zn. Statistical analyses also showed different mean levels of trace metals at the five sites. The heavy metal burdens in the sediments revealed significant variations in the distribution of the metals, with Pb showing the greatest variation and Fe the least. Enrichment level of Fe was minimal; Cu and Zn were significantly enriched and Pb showed very high to extremely high enrichment. The average geoaccumulation values and pollution load index calculated for the five studied sites indicated that the lagoon is practically unpolluted with Fe, Cu and Zn, but moderately polluted with Pb. KEY WORDS KEY WORDS KEY WORDS

The extent of heavy metal contamination viz. lead (Pb), copper (Cu) and zinc (Zn) in the soil of the University of Cape Coast School of Agricultural farmland, Ghana, were assessed. Thirty soil samples were taken from six demarcated areas in the farm. The mean metal concentrations (mean ± cv) and ranges of the

Intensified urbanization and industrialization are rapidly triggering the release of pollutants to the environment. This study determined the extent of soil contamination with Nickel (Ni) in oil mining areas and its effect on the levels of Ni tolerance by fungi and bacteria. The total CFUs/g of soil were enumerated after a culture period of 7 days at 28°C and LC50 was determined using probit and regression analysis. The mean values of Ni were 1.38±0.23 in industrial area, 1.41±0.36 ppm in agricultural area and 1.02±0.64 in urban area. The mean values of Total Petroleum Hydrocarbon (TPH) were 4,405.46 ppm in industrial area, 55.65 ppm in agricultural area and 1,304.53 ppm in urban area. Nickel’s peak concentration indicating growth of both fungi and bacteria at 150 ppm. There was significant difference (p ≤ 0.000) in the mean levels of LC50 for fungi among the study sites. There was no significant correlation between the concentration of TPH in soil and LC50 of fungi (r = -0.169) and bacteria (r = 0.042). In conclusion, TPH influenced the levels of fungi and bacteria tolerance to Ni in soils. Moreover, it was observed that LC50 can be a reliable method for monitoring chemically resistant microorganisms directly in the environment to improve the use of microorganisms for the bioremediation of oil contaminated soils and in monitoring of antibiotic resistant microorganisms in natural ecosystems.

Marine oil spillage accidents greatly impact major risks to the environment in terms of the acute and chronic adverse effects not only to the offshore, but also the coastal ecosystem. This study assessed single and joint toxicological effect of Dispersit SPC 1000 and Bonny Oil on mudskipper fish (Periophthalmus papilio) from the brackish water research station of African Regional Aquaculture Centre, Buguma, Rivers State, Nigeria. The physicochemical parameters observed throughout the study were the pH, alkalinity and salinity were 6.83 ± 0.1, 40 mg/L± 0.2 and 17,655 mg/L respectively. The temperature and Dissolved oxygen (D.O.) and specific gravity averaged 26.7 o C ± 0.1, 5.70 mg/L ± 0.02 and 1.008 ± 0.001, respectively. Dispersit SPC 1000 was found to be toxic to the mudskipper at various % (v/v) concentration, above 60 % (v/v) concentration no fish survived after one hour. The relation between the probit mortality and log concentration showed a strong positive correlation between the dispersant concentration and fish mortality within 3 hours, with r 2 = 0.813 p = 0.05;The lethal dose Lc50 was 73.48%. Within 6 hours, the mortality increased as the dispersant exposure concentration was increased (r 2 = 0.872, p =0.05). The results of exposure of the mudskippers to the water-oil-dispersant mix (CEWAF) showed lower mortalities. Mortality was observed after 72 hours for dispersant concentration above 54 %. 63% dispersant concentrations, 20% mortalities was observed between 72 and 96 hours. Dispersit SPC 1000 alone was highly toxic, and the toxicity of CEWAF was primarily caused by the presence of dispersant. There was no joint increase in toxicity between bonny oil and the chemical dispersant, as the mixing of the dispersant by the oil resulted in diminished toxicity of CEWAF and lower mortality.

This paper discusses the levels of some heavy metals (Cu and Pb) in the soil sediments of the Kakum River, its estuary and tributaries. Samples were collected at five sites, two at the estuary of River Kakum (MZ and TZ) and the other at confluence of three of its tributaries, namely Nkontro, Kakum and Sruwe. The total Cu concentrations were found to be: Nkontro, 4.656 mg/kg > Kakum, 3.197 > Sruwe 3.16 mg/kg kg > MZ, 1.893 mg/kg > TZ, 1.277 mg. The total lead concentrations were as follows: Nkontro, 6.611 mg/kg > Kakum, 6.063 mg/kg > MZ, 3.983 mg/kg > Sruwe, 3.901 mg/kg > TZ, 3.038 mg/kg. Generally, both Cu and Pb in the sediment (residue) at the five sites follow the trend Sruwe >Kakum > TZ > MZ, while the trend for the leachate was MZ > Kakum > TZ. The levels of both metals in the leachate at site MZ were higher compared to the levels at site TZ. The contamination factors and geo-accumulation index values suggest that the sediments of the river at the selected sites were not polluted with Pb and Cu.