Prediction of polycyclic aromatic hydrocarbons toxicity using equilibrium partitioning approach and narcosis model.

The study underscores the use of equilibrium partitioning (EqP) to determine bioavailability and the narcosis theory to estimate toxicity of PAHs to benthic invertebrates. Eight PAHs (anthracene, azuleno(2,1-b)thiophene, benz(a)anthracene, carbazole, dibenzothiophene, benz(a)azulene, dibenzo(a,h)anthracene and phenanthrene) were identified with phenanthrene and carbazole recording the highest (6.29 microg/g) and least (0.06 microg/g) concentrations at both seasons. Based on EqP and Narcosis model, the sum of PAHs toxic unit (SigmaTU), at both sites is <<1, suggesting no likelihood of PAHs toxicity to benthic invertebrates. The study suggests continuous PAH monitoring especially with aquatic species due to their transfer to human via food chain.