Cleanup levels are the beating heart of any environmental remediation project. They drive the approach, the cost, and the schedule for project closure. Yet, the path towards cleanup level selection is murky – one size does not fit all. In Washington State alone there are a variety of cleanup levels – set through the Model Toxics Control Act (MTCA) – and selecting the correct one for a site requires a sound understanding of site-specific data, the science of how the media at the site exists and moves, the pertinent regulatory requirements, and what, ultimately, is the site going to be redeveloped? If so, for industrial purposes? For livable space?
At a recent Technical Exchange, senior hydrogeologist Dana Cannon tackled this knotty topic in an open discussion of what we talk about when we talk about cleanup levels. Questions asked and answered included:
- What cleanup levels apply in what situations?
- What exposure pathways do different cleanup levels address?
- MTCA and other ARARs: Where do cleanup levels come from, and what’s an ARAR, anyway?
- Method A cleanup levels: when can I use these? Do I want to?
- Method B cleanup levels: now it gets complicated.
- Method C cleanup levels: when to I get to use these?
Three overarching points rung true throughout the discussion:
- Get to Know CLARC. It pays big dividends to get familiar with the Washington State Department of Ecology’s Cleanup Level and Risk Assessment (CLARC) database and MTCA.
- Exposure pathways. Understand the human and ecological exposure pathways for a given site. From there, cleanup level selection becomes clearer.
- Strategy. Strategy means knowing the site conditions backwards and forwards, knowing the end goal for the site after cleanup, and understanding which cleanup levels apply. Knowing how to approach CLARC relative to site exposure pathways puts you ahead of the game.