What condition will negate the ability to close a site under the Soil Matrix guidelines?

The presence of impacted groundwater is a critical condition that can impede the closure of a site under the Soil Matrix guidelines. These guidelines mandate that for a site to be considered for closure, contamination must be sufficiently managed or contained, ensuring that any potential risk to human health and the environment is eliminated. When groundwater is impacted, it indicates that contaminants have migrated beyond acceptable limits, potentially affecting drinking water supplies and ecosystems.

Addressing impacted groundwater often involves extensive investigation and remediation efforts to ensure that the water quality is restored to safe levels before any site closure can take place. This situation poses a significant risk scenario that complicates the closure process, as ongoing monitoring and treatment might be necessary to comply with environmental regulations. Thus, the presence of impacted groundwater is a decisive factor that prevents a site from being closed according to the Soil Matrix guidelines.