What types of materials are considered low permeability for determining Soil Matrix levels?

The correct response highlights the significance of understanding soil characteristics when assessing permeability for determining Soil Matrix levels. Low permeability materials are those that restrict the movement of water and contaminants through them, which is crucial for evaluating the potential for groundwater contamination.

Gravel and certain types of clays are indeed considered low permeability materials due to their structural properties. While gravel typically allows water to flow through it quickly, the context usually hinges on clay types that have very fine particles, effectively limiting water movement. This fine structure can create a barrier for water and contaminants, classifying them as low permeability when assessing Soil Matrix levels.

Recognizing how these materials interact with moisture and contaminants is vital in remediation and environmental protection efforts. The understanding of permeability is especially essential for professionals in the field, as it directly impacts decisions related to soil treatment, tank placement, and maintenance.