What does 'Free Product' in soil indicate?

'Free Product' in soil refers to the presence of a non-aqueous phase liquid (NAPL), typically a type of hydrocarbon, that has pooled in the soil or on the water table. This term is predominantly used in the context of environmental contamination, particularly with petroleum products like diesel or heating oil. When soil analysis indicates 'Free Product,' it means that there is an oversaturation of substances such as diesel, which can lead to environmental concerns including contamination of groundwater.

This concept is critical for understanding environmental assessments, especially during the investigation of leaks or spills from heating oil tanks. The presence of free product signifies that immediate remediation may be necessary to mitigate risks to the surrounding environment, as these hydrocarbons can negatively impact soil and water quality.

Other options represent different types of environmental concerns or stressors that do not relate to the specific definition of 'Free Product'. For example, pollution from heavy metals is a distinct issue that concerns solid contaminants not in a liquid phase. Microbial contamination pertains to biological contamination, which focuses on the presence of bacteria or other organisms, whereas limited oxygen levels in soil refer to anaerobic conditions, which can affect plant growth but do not directly indicate the presence of free product.