What is required if any constituent exceeds RBCs during a site assessment?

When a site assessment reveals that any constituent exceeds the Risk-Based Criteria (RBCs), it is essential to undergo a more thorough evaluation, which includes site closure as a full assessment. The RBCs are designed to establish limits on the acceptable concentration of pollutants based on potential risks to human health and the environment. Exceeding these thresholds indicates that contamination may pose a significant risk, necessitating an immediate and comprehensive plan to assess the scope of the problem.

Opting for a site closure means taking the necessary steps to fully understand the contamination and its implications, which may include additional testing, monitoring, and ultimately deciding the appropriate response actions. This step is crucial to ensure that no further harm occurs and that all regulatory requirements are satisfied.

While remediation might be a necessary outcome following a full assessment, initially performing a site closure is the required action when RBCs are exceeded to ascertain the full extent and implications of the contamination. Thus, conducting a full assessment is foundational before determining the appropriate remediation actions, making site closure the correct answer in this context.