Behaviour of selected polycyclic aromatic hydrocarbons associated with stabilized oil and coal ash artificial reef

Abstract

An experimental artificial reef consisting of oil and coal fly ash stabilized with cement and lime has been placed in the Atlantic Ocean off the east central coast of Florida. The oil and fly ash were found to contain levels of polycyclic aromatic hydrocarbons (PAH) similar to a moderately contaminated sediment. Detectable concentrations of individual PAH ranged from highs in the oil ash of 1200 and 270 ng g −1 to lows of 250 and 49 ng g −1 in stabilized bricks for fluoranthane and naphthalene, respectively. The stabilization process used in the construction of the reef bricks reduced the extractability of PAH from reef bricks by hot organic solvents. Because of the toxicity of some PAH, there is concern for leaching of the PAH by seawater from the waste ash used for construction of the reef. Leaching studies of the reef materials with seawater, however, indicated PAH are retained within the reef materials and that seawater is not an effective medium for removing PAH from reef bricks or the ash. Furthermore, the reef materials were found to adsorb PAH from the seawater phase. These results indicate that the stabilization of oil ash is an efficient tool for isolating PAH from environmental circulation.