Which sample type is acceptable for obtaining closure for a Soil Matrix site?

Obtaining closure for a Soil Matrix site requires a reliable method for assessing the condition of the soil and any potential contamination present. Soil samples are the most direct and informative type of sample for this purpose because they allow for the analysis of contaminants that may be present in the soil matrix itself. This analysis can determine the extent of contamination, if any, and whether it meets regulatory standards for closure.

Soil samples provide a comprehensive understanding of the site condition by revealing the concentration of contaminants at various depths, which is critical for making informed decisions about remediation and site closure. In contrast, water samples might indicate transport mechanisms for contaminants, but they do not give insights into the soil itself. Air samples can reveal volatile contaminants but do not account for those that are bound to the soil. Similarly, contaminant readings from nearby vegetation do not directly reflect the soil matrix and may not accurately represent the contamination levels or distribution necessary for assessing closure. Therefore, soil samples are distinctly the most appropriate and acceptable means for obtaining closure in this context.