Potential Impacts of an Orimulsion Spill on Marine (Atlantic Herring; Clupea harengus ) and Estuarine (Mummichog; Fundulus heteroclitus ) Fish Species in Atlantic Canada

摘要

The growing potential of emulsified bitumal products for fuel such as orimulsion (an emulsion of 70% bitumen in 30% water) warrants further assessment of their possible environmental impacts associated with spills. In the event of a spill at sea orimulsion may contact animals throughout the water column rather than only at the water surface as expected by conventional heavy fuel oils. In this study we tested orimulsion toxicity during the embryonic development of an estuarine (mummichog; Fundulus heteroclitus) and a marine (Atlantic herring; Clupea harengus) fish species in duplicate assays for each species. Air injection and varying salinities were included in the herring assays to examine their effects on orimulsion toxicity. Water-accommodated fractions (WAF) of No. 6 fuel oil were also tested in the mummichog assays to compare orimulsion toxicity to that of a heavy fuel oil. Significant impacts were observed at the lowest tested concentration of 0.001% orimulsion in both species. In the more sensitive of the two species, herring, this concentration produced 100% abnormal larvae. Similar abnormalities were produced in both herring and mummichog, including reduced growth, pericardial edema and spinal deformities. These are also the same types of abnormalities produced by heavy fuel oils and PAHs. The initial and most prominent abnormality was peripericardial edema, which was usually accompanied by haemorrhaging at its base in mummichog. Orimulsion-exposed fish also suffered from increased mortality, reduced heart rates, premature hatch and reduced lengths. The toxicity of orimulsion was over 300x greater than #6 fuel oil (WAF). Although effect of salinity on orimulsion toxicity in herring was unclear, air injection greatly reduced toxicity.