Occurrence and Toxicity of Hydrocarbon Residues in Crab (Callinectes sapidus) from Contaminated Site

Abstract

To elucidate seasonal changes in hydrocarbons including polycyclic aromatic hydrocarbons (PAHs) due to oil spill, tissues of blue crab (Callinectes sapidus) were investigated. Total petroleum hydrocarbons (n-alkanes) concentrations ranged from 0.17-0.32µg/gdw and 0.28-0.62µg/gdw during the dry and wet seasons respectively. The tissues accumulate a complex spectrum dominated by heavier hydrocarbons, alkylsubstituted and PAHs. The impact of biogenic contribution through dietary uptake was related to the elevated levels, particularly of the PAHs. Studies of other site specific, resident organism are recommended in order to be able to establish the extent of toxicity. @ JASEM There are volumes of literature and critical reviews on the measurement of hydrocarbons including PAHs and their bio-transformation in biological tissues for health effect monitoring, in sediments and mollusks for environmental monitoring, and foodstuffs for safety reasons (Hair, 1998; William et al., 1997; Stroomberg et al., 2004; Shi et al., 2006). Uptake of hydrocarbons, particularly PAHs compound by aquatic biota is very rapid. Invertebrates, especially mollusks, do not metabolise PAHs as efficiently and may accumulate high tissue concentrations (Eisler, 1987, Varanasi et al, 1989). The PAHs are relatively stable constituent of petroleum and many of these compounds are potentially toxic, caranogenic and mutagenic (Ghauch et al., 2000, Aderemi et al., 2003). Previous studies within the area were conducted with the traditional gravimetric method (Asaolu, 1998). Their result however, revealed high concentrations of gravimetric TPH in the water and more in the sediment which are major means of transfer into crab. As a result of the complex nature