Ned Black, US EPA R9 CERCLA Ecologist channeling John Hillenbrand, US EPA R9 CERCLA Mining
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Transcript of Ned Black, US EPA R9 CERCLA Ecologist channeling John Hillenbrand, US EPA R9 CERCLA Mining
Ned Black, US EPA R9 CERCLA EcologistchannelingJohn Hillenbrand,US EPA R9 CERCLA MiningCoordinator
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
Lake Hg Concentration Gold Minesin fish (mg/kg) in Basin
Patagonia 0.2 52
Arivaca 1.0 -1.5 0
Pena Blanca 1.3 -1.5 2
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