Aromatic hydrocarbon "humps" in the marine environment: Unrecognized toxins?

Gas chromatographic analysis of the hydrocarbons of environmental samples o ften reveals that unresolved complex mixtures (UCMs) or gas chromatographic "humps" of aliphatic and aromatic hydrocarbons are most abundant-yet littl e consideration seems to have been given to the possible toxicological impa cts of hydrocarbon "humps". Here we show, using a well-accepted bioassay, t hat monoaromatic components of a UCM of hydrocarbons from a crude oil elici t a sublethal toxic response in a typical marine pollution indicator organi sm (the mussel, Mytilus edulis). Furthermore, coastal U.K. mussels shown pr eviously to have unexplained impaired health contained high concentrations of UCMs, including monoaromatic UCMs. These findings may have important imp lications for our understanding of the toxicological sublethal effects of o il residues in the environment. Given the relatively resistant nature of UC M hydrocarbons, the effects of both acute oil spills and more chronic disch arges may need further consideration.