∑PAH: A MODEL TO PREDICT THE TOXICITY OF POLYNUCLEAR AROMATIC HYDROCARBON MIXTURES IN FIELD-COLLECTED SEDIMENTS

摘要

The ∑PAH model estimates the probability of toxicity of PAH-contaminated sediments using a combination of equilibrium partitioning, QSAR, toxic unit, additivity, and concentration-response models. The sediment concentration of organic carbon and 13 PAH (polynuclear aromatic hydrocarbon) compounds were measured. Interstitial water concentrations (PAH_(iw)) of the 13 compounds were predicted by equilibrium partitioning. The 10-d LC50 of each compound in interstitial water (10-d LC50_(iw)) was predicted by a QSAR regression of 10-d LC50_(iw) (from spiked sediment tests) to K_(ow). Toxic unit concentrations of individual compounds (TU_i) were predicted as PAH_(iw)/10-d LC50_(iw). The total number of toxic units of the 13 compounds (∑TU_i) was calculated assuming the additivity of toxic effects of PAHs. ∑TU_i was used to predict the probability of toxicity to marine and estuarine amphipods using a concentration-response model derived from spiked sediment toxicity tests. The ∑PAH model was verified by comparing predicted and observed toxicity in field-collected sediment samples. There was 86.6% correspondence and no significant difference between predicted and observed toxicity at PAH-contaminated sites. Ecological-effect levels predicted by the ∑PAH model correspond with several sediment-quality guidelines.