Toxicity of six representative polycyclic aromatic compounds in five marine test species

Toxicity data for single polyaromatic compounds (PACs) are needed to develop models to predict impacts to aquatic life resulting from oil spills and environmental releases of hydrocarbons. To support this objective, the toxicity of six representative PACs: naphthalene, dibenzothiophene, phenanthrene, pyrene, floranthrene and chrysene; were investigated in five marine test species: Purple sea urchins (Strongylocentrotus purpuratus), Mediterranean mussel (Mytilus galloprovincialis), Mysid shrimp (Americamysis bahia), Inland silversides (Menidia beryllina) and Sheepshead minnow (Cyprinodon variegatus). Acute and chronic toxicity tests were expressed based on measured exposure concentrations of each PAC. Results indicated that exposure concentrations were not sufficiently high to produce chronic effects for the less soluble PACs investigated. Acute toxicity results were used to develop species-specific quantitative effect models using the target lipid model (TLM). Mysid shrimp were the most sensitive species investigated. Acute-to-chronic ratios derived using chronic data for mysids and silversides ranged from 1.2 to 3.4 across the PACs that exhibited toxicity. A comparison of measured chronic toxicity data to TLM-derived Hazard Concentrations (HC5s) derived using acute toxicity data for marine organisms and acute to chronic ratios indicated the protectiveness of the TLM. These results support the technical basis of applying the TLM in marine life hazard assessment.