ECORISK-BASED ESTIMATION OF PETROLEUM HYDROCARBON TOXICITY IN COASTAL SEDIMENTS

摘要

Polycyclic aromatic hydrocarbons (PAHs) are the most important contributors to the toxicity of soils and sediments contaminated with weathered crude or refined oil. Therefore, we estimated the toxicity of petroleum products in sediments, based on concentrations of petroleum PAHs. We used equilibrium partitioning to estimate concentrations of individual petroleum hydrocarbons in sediment pore water in equilibrium with petroleum in the bulk sediment. We developed a regression equation relating log K_(ow) of individual petroleum hydrocarbons to toxicity to freshwater and marine animals. The estimated concentration of each hydrocarbon in pore water of each sediment sample was divided by the chronic toxicity of that hydrocarbon to yield a hazard quotient (HQ). HQs for all the hydrocarbons in the sample were summed to produce a hazard index (HI). HIs greater than 1 indicate that the hydrocarbons are present in the sediment sample at a concentration that could pose a risk of toxicity to marine organisms. We give examples of HI calculations for two oil-contaminated sediment/soil samples from crude oil spills in northern Italy.