Image Number 4 for United States Patent #4834194.
The invention relates to methods and apparatus for agitating and heating a sub-surface volume of soil to liberate volatile compositions therefrom which are transmitted through a special flow passage created through the soil to the soil surface where they are analysed to determine the presence or absence of selected contaminants. A low pressure sink is provided to ensure proper flow of volatiles rapidly to the surface and to prevent contamination of adjacent soil blocks or cylinders during treatment.
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