Interstitial gases

Interstitial gases or “soil gases” are gases and vapors that are present in the intergranular spaces of the subsoil; they are generated by microbiological or geological phenomena or by an environmental contamination.

Mérieux NutriSciences has specific soil gas probes to be used for active sampling: they are placed in the unsaturated soil to extract gases by means of vacuum pumps. The installation takes place at survey points, through direct push technology, or vapor pin or even by inserting the probes directly into the soil. Thanks to the official methods, Mérieux NutriSciences determines the peculiar compounds being present in the stratum and in the soil.

Gas analysis can be performed directly on site through colorimetric kits, portable flame ionization detectors (FID), photoionization detectors (PID), and infrared detectors (IR). If laboratory tests are carried out for more complex investigations, the sample is collected by Canister or adsorbent support, such as activated carbon.

The sampling and analyses of interstitial gases (also referred to as “soil atmosphere”) are usually carried out near contaminated areas to assess gas migration, in support of reclamation activities or in the assessment of the risk of inhalation of vapors; this activity is also used to better define the extent of the source of contamination or to verify the effectiveness of remediation technologies. Detecting contamination thus allows a prompt action in case of contamination by blocking the expansion of volatile polluting compounds.