Effects of pyrolytic and petrogenic polycyclic aromatic hydrocarbons on 1 swimming and metabolic performance of zebrafish contaminated by 2 ingestion 3 4

Depending on their origins, polycyclic aromatic hydrocarbons (PAH) are characterized by different chemical properties. Petrogenic PAH (e.g. from fossil fuels) and pyrolytic PAH (e.g. those produced by incineration processes) are therefore expected to affect organisms differently. The impact of trophic exposure to these PAH was investigated on swimming and metabolic performance of zebrafish Danio rerio. Two-month-old juveniles and six-month-old adults were individually challenged following a swimming step protocol. While pyrolytic exposure did not affect fish whatever the duration of exposure, it appeared that petrogenic PAH impaired adults’ performance. Indeed, the active metabolic rate in petrogenic PAH-contaminated adults was significantly reduced by 35%, and critical swimming speed by 26.5%. This was associated with cardiac abnormalities, which are expected to contribute to the reduction of oxygen transport, particularly during intensive effort. These results may be due to the different composition and toxicity of PAH mixtures.