Hydrocarbon-contaminated soil bioremediation in Antarctica: Effectiveness of two consecutive year?s field assays in Carlini Station

GUREVICH, JUAN MANUEL; MARTINEZ ALVAREZ, LUCAS MANUEL; RUBERTO, LUCAS; MAC CORMACK, WALTER

Kuala Lumpur

Congreso; Scientific Committee of Antarctic Research: Biennial meetings and open science conference 2016; 2016

Scientific Committee of Antarctic Research

Soil contamination in Antarctica requires the development of simple remediation protocols, because availability of machinery and facilities is, in general, scarce. Bioremediation  -and biostimulation in particular-provides a simple, low cost and effective tool to mend these soils. In this work, we compare the performance of two consecutive biostimulation field  assays using biopiles. Assays were performed during 2013/2014 and 2014/2015 Argentinian Antarctic Expeditions in Carlini Station (25 de Mayo Island, South Shetland Islands). The treated soil  ?  approximately 480kg soil per system-was located on 800 µm polyethylene geomembrane and covered after amendment with Nitrogen and Phosphorus sources (Biostimulated systems, BS) in a previously optimized C:N:P ratio (Martinez Alvarez et al 2015). Similar biopiles without the addition of nutrients were analyzed as well (Control systems, CC). Hydrocarbon removal percentages, biological activity, total and hydrocarbon-degrading bacterial counts, temperature, conductivity and moisture (in and outside the biopiles) were evaluated during the entire experiments, both years. The results showed that the first-year field assay was more efficient in the removal of hydrocarbons from soil. Biostimulated system removed 75.79% of the contaminant in 50 days, while control biopile only 49.54% in this first assay. In the second experimen t, BS biopile reached 55.04% of removal, and CC biopile 41.73%. Total bacterial counts and biological activity reached higher values in the first year; while degrading bacterial counts were higher in the second one, but no significant differences were found in these parameters between both years. In any case, when compared with results from the systems in which no biostimulation was performed, nutrient addition proved to enhance microbial activity. Significant differences were found between the temperatures  reached inside biopiles between both years. The difference between temperature inside the biopile and surrounding soil climbed up to 1.3°C the first year, while only 0.3°C was the difference in the second year. This fact suggests the possibility that differences in the hydrocarbon removal efficiency in biopiled field assays could be related to differences in the internal temperature of the biopiles, factor that clearly is strongly influenced by environmental temperature and total solar radiation received by the experimental systems.