It is well-known that LFG migration and its impacts on the environment are difficult to quantify. However, specific quantitative and semi-quantitative tools (gas fingerprinting) for evaluating offsite LFG migration and impacts have been developed.
One of these tools includes “fingerprinting” LFG to compare it to the detected gaseous impacts in the subsurface and tracking those impacts back to the landfill. The fingerprinting technique can also be used to trace the source of methane (the primary component of LFG) to its source, which can include LFG but also natural (thermogenic) gas, petrogenic (petroleum-derived) gas, or other sources of biogas (e.g., swamp gas).
Another technique includes “tracer” studies, which are used to confirm the existence of releases of LFG and quantify the resulting offsite impacts. Traditional chemical release, air dispersion modeling, and risk assessment techniques have also been used.