HYDROCARBON SPILL AT PUERTO MADRYN PORT, PATAGONIA ARGENTINA: SITE CHARACTERIZATION AND BIOSTIMULATION FIELD TRIAL

SEPULVEDA M.A.; DEL BRIO F.; REVUELTA F.; POLIFRONI R.; OLIVERA N.L.; NIEVAS M.L.

Río de Janeiro

Simposio; 9th Latin American Biodeterioration and Biodegradation Symposium - LABS 9; 2016

National Institute of Technology

Bioremediationof is the most important mechanism of environment recovery of  hydrocarbon-impacted shore lines, either as a naturallyoccurring or technologically assisted process after physical cleaning orcontention actions. The addition of nutrients (biostimulation) is a probedstrategy for enhancing natural biodegradation rates. A drifting ship hell overat Puerto MadrynPort (42° 46? S, 65° 02? W, Patagonia Argentina) releasing an unknown amount of fueland bilge waste hydrocarbons in August 2015. The spilled oil impacted the GolfoNuevo waters and the harbour beach. Oil contention actions and recovery fromsurface water was performed around the sunken ship. The aim of this work was toevaluate hydrocarbon fate in the harbour sediments and to test the effect ofslow-release nutrient addition in hydrocarbon removal. Near the impacted site,9 days after the spill, hydrocarbon concentrations in intertidal surficialsediments were in the order of 10 mg/kg dry sediment (TNRCC 1005 method).Hydrocarbons had biogenic and petrogenic features, with a bimodal unresolvedcomplex mixture (UCM) profile compatible with  fresh diesel oil along with a weathered heavier UCM, likely from bilgewastes or older contamination.  Thebiostimulation experiment started 13 days after the spill (T0) at the surficialsediment in the impacted site. A completely randomized block design was used, eachof 5 blocks contained natural attenuation (NA, without addition nutrients) and abioestimulation with slow-release nutrients (BS) treatments. The abundance ofpetroleum-degrading microorganisms was in the range of 1-3 E4 MPN g-dw-1,showing no significantly differences neither during the experiment nor betweentreatments. Naphathalene-degrading microorganism counts were in the range of0.2-1 E4 MPN g-dw-1, being significantly lower during the BStreatment than at the initial time (T0). Hydrocarbon contents were in the orderof 10 mg/kg dry sediment after one month of treatment, showing a unimodal heavyUCM and biogenic features. Except for one site, where profiles of fresh dieseloil cuatriplicated the hydrocarbon contents of other sites evidencing apunctual reingression of hydrocarbons, no hydrocarbon-biodegradationenhancement attributable to BS treatment was found. This could be due to thelow initial level of hydrocarbons and the nutrient availability from seedweeds.Finally, the impacted beach at Puerto Madryn showed a quick recovery that maybe based in the beach energy of the zone.