Bioconcentration of Water Soluble Fraction (WSF) of crude oil in <i>Oreochromis niloticus</i>

Abstract

Bioconcentration of water soluble fraction of Australian crude oil in 50 fingerlings of Oreochromis niloticus was conducted under laboratory conditions for 28 days. An initial acute toxicity test was carried out using different concentrations (25ml/L, 50ml/L, 75ml/L, 100ml/L and a control) of the water soluble fraction (WSF) of crude oil. The LC₅₀ was 28.18 ml/L and LT₅₀ were 35.5 hours, 63.1 hours, 79.4 hours and 100 hours for 100ml/L, 75ml/L, 50ml/L and 25ml/L respectively. From the LC₅₀, two concentrations (4.4ml/L and 2.2ml/L) were used to determine the bioconcentration on day 4, 7, 14, 21, and 28. The concentration of hydrocarbon in the fish tissue and test solution increased with increase in exposure time and subsequent increase in bioconcentration factor (BCF).Significant variation existed between the two concentrations of WSF of the crude oil (F= 6.26 ≥ P=0.0370.05). This implies that WSF of crude oil bioconcentrates in the tissue of aquatic organisms and may have detrimental health implications for fish consumers. Therefore, appropriate measures should be adopted for efficient effluent treatment technology and avoidance of oil spillage into the aquatic environment in the Niger Delta.

Keywords: Bioconcentration, Water Soluble Fraction (WSF) of Crude Oil, LC₅₀, LT₅₀