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HYDROCARBON SPILL AT PUERTO MADRYN PORT, PATAGONIA ARGENTINA: SITE CHARACTERIZATION AND BIOSTIMULATION FIELD TRIAL
MARCELA SEPÚLVEDA; FEDERICO DEL BRIO; F. REVUELTA; ROSANA POLIFRONI; NELDA LILA OLIVERA; MARINA NIEVAS
Río de Janeiro
Simposio; LABS9 Latin American Biodeterioration and Biodegradation Symposium; 2016
Bioremediation of is the most important mechanism of environment recovery of hydrocarbonimpacted shore lines, either as a naturally occurring or technologically assisted process after physical cleaning or contention actions. The addition of nutrients (biostimulation) is a probed strategy for enhancing natural biodegradation rates. A drifting ship hell over at Puerto Madryn Port (42° 46? S, 65° 02? W, Patagonia Argentina) releasing an unknown amount of fuel and bilge waste hydrocarbons in August 2015. The spilled oil impacted the Golfo Nuevo waters and the harbour beach. Oil contention actions and recovery from surface water was performed around the sunken ship. The aim of this work was to evaluate hydrocarbon fate in the harbour sediments and to test the effect of slow-release nutrient addition in hydrocarbon removal. Near the impacted site, 9 days after the spill, hydrocarbon concentrations in intertidal surficial sediments were in the order of 10 mg/kg dry sediment (TNRCC 1005 method). Hydrocarbons had biogenic and petrogenic features, with a bimodal unresolved complex mixture (UCM) profile compatible with fresh diesel oil along with a weathered heavier UCM, likely from bilge wastes or older contamination. The biostimulation experiment started 13 days after the spill (T0) at the surficial sediment in the impacted site. A completely randomized block design was used, each of 5 blocks contained natural attenuation (NA, without addition nutrients) and a bioestimulation with slow-release nutrients (BS) treatments. The abundance of petroleum-degrading microorganisms was in the range of 1-3 E4 MPN g-dw-1, showing no significantly differences neither during the experiment nor between treatments. Naphathalene-degrading microorganism counts were in the range of 0.2-1 E4 MPN gdw-1, being significantly lower during the BS treatment than at the initial time (T0). Hydrocarbon contents were in the order of 10 mg/kg dry sediment after one month of treatment, showing a unimodal heavy UCM and biogenic features. Except for one site, where profiles of fresh diesel oil cuatriplicated the hydrocarbon contents of other sites evidencing a punctual reingression of hydrocarbons, no hydrocarbon-biodegradation enhancement attributable to BS treatment was found. This could be due to the low initial level of hydrocarbons and the nutrient availability from seedweeds. Finally, the impacted beach at Puerto Madryn showed a quick recovery that may be based in the beach energy of the zone.