Ned Black, US EPA R9 CERCLA Ecologist channeling John Hillenbrand, US EPA R9 CERCLA Mining Coordinator Cordero

NPL Superfund Steps Remedial Investigation = – Nature and Extent, – Conceptual site model, – Risk based cleanup goals = 0.2 mg/kg MeHg in fish Feasibility Study = – Options for cleanup Record of Decision = – What is the action we going to take at this site

Mercury Levels in Fish vs Mine Sources in Watershed LakeHg Concentration Gold Mines in fish (mg/kg) in Basin Patagonia Arivaca Pena Blanca

Our Challenges/Assumptions at Hg Sites* Successful remediation requires source control Hg methylation and subsequent biomagnification in the food web can be hyper efficient Air deposition Hg won’t be ignored Dollars for removals and remediation are scarce Stakeholders** prefer we spend $$ on successful projects *Not a complete list ** e.g., Citizens, Congress, HQ Bean Counters