Fate of petroleum hydrocarbons in bioturbated pristine sediments fromCaleta Valdés (Patagonia Argentina): An ex situ bioassay

JULIETA STURLA LOMPRE; MARINA NIEVAS; MARCOS FRANCO; VINCENT GROSSI; AGUSTINA FERRANDO; CÉCILE MILITON; FRANCK GILBERT; PHILIPPE CUNY; GEORGES STORA; MARCELA SEPULVEDA; JOSE LUIS ESTEVES; MARTA COMMENDATORE

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2018

0147-6513

Petroleum can pollute pristine shorelines as a consequence of accidental spills or chronic leaks. In this study, thefate of petroleum hydrocarbons in soft pristine sediment of Caleta Valdés (Argentina) subject to ex situ simulatedoil pollution was assessed. Sedimentary columns were exposed to medium and high concentrations of EscalanteCrude Oil (ECO) and incubated in the laboratory during 30 days. Levels of aliphatic hydrocarbons at differentdepths of the sedimentary column were determined by gas chromatography. Oil penetration was limited to thefirst three centimetres in both treatments, and under this depth, hydrocarbons were clearly biogenic (terrestrialplants) as in the whole sedimentary column of the control assay. Bioturbation by macrobenthic infauna wasstrongly impacted by oil pollution which resulted in reduced sediment oxygenation and low burial of petroleumhydrocarbons. This may partly explain the limited hydrocarbon biodegradation observed, as indicated by therelatively high values of the ratios nC17/pristane, nC18/phytane, and total resolved aliphatic hydrocarbons/unresolved complex mixture. Correspondingly, at the end of the experiment the most probable number of hy-drocarbon-degrading bacteria reached ~ 103MPN g−1dry weight. These values were lower than those found inchronically polluted coastal sediments, reflecting a low activity level of the oil-degrading community. The resultshighlight the low attenuation capacities of Caleta Valdés pristine sediments to recover its original characteristicsin a short time period if an oil spill occurs. In this work, we present a novel and integrative tool to evaluate thefate of petroleum hydrocarbons and their potential damage on pristine sediments.