Tennessee Valley Authority · NYSE:TVC
Tennessee Valley Authority — Technical Presentation (May 2012)
20 slides from Tennessee Valley Authority's technical presentation, May 17, 2012
Slide 1: River Systems Investigations Update
River Systems Investigations Update TVA Kingston Ash Recovery Project Presentation 5 of 6 May 17, 2012 TVA Restricted Information - Deliberative and Pre-Decisional Privileged
Slide 2: Agenda
Agenda • Purpose • Overview of presentation series • Human Health Risk Assessment • Baseline Ecological Risk Assessment TVA Restricted Information - Deliberative and Pre-Decisional Privileged
Slide 3: Purposes of Briefings
Purposes of Briefings • Process leading to residual ash decision • Information that will support decision • Preview results of river investigations TVA Restricted Information - Deliberative and Pre-Decisional Privileged
Slide 4: Preview of "Upcoming Attractions"
Preview of “Upcoming Attractions” Tonight’s focus: Risk Assessment Process and Results April 5: Residual ash nature & extent, transport modeling April 19: Aquatics Results (toxicity testing, bioaccumulation in invertebrates & fishes) May 3: Wildlife Results (birds, turtles, mammals, plants) May 17:
Slide 5: Risk Assessments
Risk Assessments Purposes: • Support decision‐making process for the River System – Engineering Evaluation/Cost Analysis (EE/CA) • Human Health Risk Assessment (HHRA) evaluates the potential effects on people of ash residuals in the river system • Baseline Ecological Risk Assessment (BERA) evaluates
Slide 6: HHRA Receptors and Exposures
HHRA Receptors and Exposures • Adult and Child Off‐Site Residents – Surface water – household use (i.e., potable water) – Fish Consumption – fillet only (approximately 1 pound/week, every week) • Adult and Adolescent Recreators – Surface water – swimming – Sediments – during winter pool when Watts B
Slide 7: HHRA Process
HHRA Process • Cancer Risk – EPA acceptable excess cancer risk range of 10‐6 to 10‐4 – Acceptable risk: increase above background cancer rate of one additional person in 1 million to 1 additional person in 10,000 developing cancer • Non‐Cancer Hazards – Expressed in terms of Hazard Quotient (HQ) and
Slide 8: HHRA Results—Residents and Recreators
HHRA Results—Residents and Recreators ▪ No unacceptable human health risks associated with residual ash ▫ Ash‐related excess cancer risks generally well below 10‐4 ▫ Ash‐related HQs & HIs typically ranging from 0.01—1.0 ▪ Continuing risks for fish consumption due to legacy contamination (Hg, PCBs) ▫
Slide 9: River System BERA Approach
River System BERA Approach • Comprehensive and Robust – All potentially exposed and sensitive receptors evaluated – Emphasis on site‐specific data – Several types of data collected • Lines of Evidence (LOEs) combined using Weight‐of‐Evidence (WOE) process • Recommendations for Risk Management – Fina
Slide 10: BERA Agenda
BERA Agenda • BERA Bottom Line (key findings) • What is Ecological Risk Assessment? • BERA Approach for the River System Investigation • Summary and Recommendations by Receptor • Summary and Recommendations by Reach • Conclusions TVA Restricted Information - Deliberative and Pre-Decisional Privilege
Slide 11: Key Findings
Key Findings • No ecological receptors at High Risk • One receptor at Moderate Risk w/ Risk Management Recommended – Benthic invertebrate community in Emory River. • Two receptors at Low Risk w/ Risk Management Recommended – Birds feeding on benthic invertebrates (e.g., killdeer) in the Emory and Cl
Slide 12: What is Ecological Risk Assessment?
What is Ecological Risk Assessment? • Iterative Process – Starts simple and highly conservative Analysis – Becomes more detailed and realistic Collect – Focus on potential risk drivers Information • Estimates the magnitude and likelihood of adverse effects Risk Characterization • Scientifically soun
Slide 13: River System BERA Approach
River System BERA Approach • Comprehensive and Robust – All potentially exposed and sensitive receptors evaluated – Emphasis on site‐specific data – Several types of data collected • Lines of Evidence (LOEs) combined using Weight‐of‐Evidence (WOE) process • Recommendations for Risk Management – Fina
Slide 14: Plants and Animals Evaluated (Assessment Endpoints)
Plants and Animals Evaluated (Assessment Endpoints) Protection of balanced communities or populations of: • Fishes • Benthic invertebrates • Aquatic plants • Aquatic‐ or riparian‐feeding birds – Herbivores (wood duck) – Omnivores (mallard; killdeer) – Piscivores (osprey; great blue heron) • Aquatic‐
Slide 15: Types of Data (Lines of Evidence)
Types of Data (Lines of Evidence) • Field Studies (Biosurveys) – Population and community data – Fish community – Benthic Invertebrate Community – Tree swallow nest box surveys Biosurveys – Turtle trapping Relevance • Laboratory Studies Toxicity Tests – Toxicity tests – Surface water – Sediment and
Slide 16: Putting it All Together (Weight-of-Evidence)
Putting it All Together (Weight‐of‐Evidence) • Not a Mathematical Formula – Analyses are quantitative, but – Conclusions are qualitative • Potential Risk – High – Moderate – Low – Negligible • Confidence in Risk Determination – High – Moderate – Low • Risk Management Recommended? – Yes or No – If Ye
Slide 17: BERA Risk Summary by Receptor
BERA Risk Summary by Receptor TVA Restricted Information - Deliberative and Pre-Decisional Privileged 17
Slide 18: BERA Risk Summary by Reach
BERA Risk Summary by Reach TVA Restricted Information - Deliberative and Pre-Decisional Privileged 18
Slide 19: BERA Summary and Recommendations
BERA Summary and Recommendations • Ecological risks from exposure to ash or ash‐related COECs are, at most, moderate in the Emory River and low or negligible elsewhere in the river system. • None of the assessment endpoints are estimated to be at high potential risk in any of the river reaches. • Ec
Slide 20: Preview of "Upcoming Attractions"
Preview of “Upcoming Attractions” June 7: Development of General Response Actions Alternatives Evaluation TVA Restricted Information - Deliberative and Pre-Decisional Privileged
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