Maria Vilma Faustorilla
University of South Australia, Australia
Title: Fractionation of total petroleum hydrocarbons in soil by SPE-GC for toxicity studies to Eisenia fetida
Biography
Biography: Maria Vilma Faustorilla
Abstract
As petroleum is a complex mixture of hydrocarbons, the ecotoxicity of petroleum-contaminated soils has been based mostly on the total petroleum hydrocarbon (TPH) load. However, a requirement of environmental fate and risk analysis is the separation of TPH into its aliphatic and aromatic components appropriately due to the toxicity differences between the fractions. This study developed a fractionation method for TPH in soil using solid phase extraction (SPE) technique followed by analysis utilizing gas chromatography (GC) coupled to mass selective detector and flame ionization detector systems. Validation results suggested that method performance are related to molecular weight, molecular structure and soil organic matter content; thus, providing important information on the behaviour of the individual hydrocarbons such as adsorption into soil which is significant in determining environmental fate and weathering of hydrocarbons. Three soil samples contaminated with aliphatic and aromatic components were collected to determine earthworm chronic toxicity. Lethality and sub-lethal effects on days 7, 14, 21 and 28 were investigated on Eisenia fetida. The toxicity studies showed that aromatic fractions exerted increased lethal effects upon concentration on earthworms occurring at lower concentrations as compared to the aliphatic fractions, which only showed adverse effects at higher concentrations. This work emphasized the need to determine the fractions of TPH in a contaminated soil, instead of using TPH as a single hydrocarbon index, to have a more accurate assessment towards ecological hazards and impact.