PAH phototoxicity––an ecologically irrelevant phenomenon?

Photoenhanced toxicity of polycyclic aromatic hydrocarbons (PAH) is well demonstrated in laboratory and in a few in situ studies. Effects have been observed for multiple taxa and toxicological endpoints, and the mechanism of toxic action has been described. However, this phenomenon is ameliorated by physical, chemical and biotic factors. The ecological relevance of PAH phototoxicity remains uncertain; it should not be used for environmental management decisions unless its ecological relevance is firmly established, and then only as part of a weight of evidence determination.