Trace Analyses of Hydrocarbons to Understand the Fate of These Contaminants in Aquifers

In recent years, it has become increasingly evident that the problems related to soil and groundwater pollution are of major concern in industrial countries. The persistence of contamination in the environment and the toxicity of pollutants have led to important investigations and researches in this field. The competent authorities have set up regulations and methodologies to face the problems of contaminated sites in order to repair the errors of the past in a pragmatic way. These are risk based tools and take into account both water resources and health. They allow the treatment to be adjusted to the future use of the site. In this context, understanding the mechanisms of pollution transfer from the soil to the water phase becomes crucial to evaluate the quantitative and qualitative impact on the water resources. As a matter of fact, numerous processes-physical, chemical and in particular biological-are susceptible to affect the quantity and particularly the composition of the contaminant. This paper will present methodologies allowing the biological fate and the physical state of hydrocarbons in water to be perceived. Results from two real cases will be presented: the first one contaminated with gasoline and generating an important plume of dissolved monoaromatic compounds and the other one contaminated with coal tars inducing a pollution with polyaromatic hydrocarbons