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Single and Joint Toxicological Effect of Dispersit SPC 1000 and Bonny Oil on Mudskipper Fish ( PeriophthalmusPapilio ) from the Brackish Waters of Buguma, Rivers State, Nigeria
KORANTENG-ADDO, EJ; HORSFALL, M Jnr; JOEL, OF & BENTUM, JK
Abstract
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 r2 = 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 (r2 = 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.
Keywords
Joint Toxicity; Dispersit SPC1000; Mudskipper Fish
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