development of the provisional radiological look up table...2013/01/30 · provisional look-up...
Post on 27-Sep-2020
1 Views
Preview:
TRANSCRIPT
January 30, 2013
DTSC Chatsworth Office Marina Perez
Raymond Leclerc Mark Malinowski
Laura Rainey
Ground Rules
2
Please: • Silence all mobile phones, PDAs, tablets and electronics • Limit cross conversation during the meeting • Treat other people with the same level of respect you expect
from others • Hold all questions until the designated question and answer
period(s)
Photography, sound and video recording may occur during this meeting. If you do not wish to be filmed or photographed please inform the
photographer/videographer directly.
Agenda
Introduction/Ground Rules
Meeting Goals
Radiological Look-Up Table Process
Administrative Orders on Consent
EPA Recommendations Recap
Example Radionuclides
Timing and Use of Provisional Values
Next Steps
3
Meeting Goals
DTSC will describe the development of the Look-Up Table process and the community’s role in that process Review how the Look-Up Table is described in the AOC Explain how the Look-Up Table process complies with the
AOC Considerations while establishing the Look-Up Table values Review the process going forward, highlighting opportunities
for the community to stay informed
DTSC will describe how the Look Up Table process will be
applied for: Remediation planning Confirmation
4
2011 2017 2012 2013 2014 2015 2016
Building Demolition
Chemical Data Gap Investigation
Treatability Studies
EPA Rad Sampling/ DTSC Chemical Co-Located Sampling
Soils Remedial Action Implementation Plan
Approved Plan
Soils Cleanup Implementation
Confirmation Sampling
Final Rad Data Report
Final Chem Data Report
Anticipated SSFL Project Timeline January 30, 2013
Feb 2013
CEQA Scoping CEQA Assessment
CEQA Document
EPA Rad Background
Study
DTSC Chemical Background Study
Final Rad Background
Report
Final Chem Background
Report
Provisional Rad Lookup
Tables
Chem Lookup Tables
Final Rad Lookup
Tables Rad Lab Selection
Administrative Order on Consent
DTSC is responsible for the enforcement and implementation of the AOCs – including establishing Look-Up Table values
Although the AOCs state what will be included in the Look-Up Table, it does not provide specific values, nor detail the process to define those values
DTSC is responsible for establishing the Look-Up Table with technical input from EPA
6
Administrative Order on Consent What does the AOC tell us about what the Look-Up
Table values should be?
“Upon completion of the EPA led radiological local background study, a “look-up” table of the radiological cleanup levels will be prepared, which will include both local background concentrations as well as minimum detection limits for specific contaminants whose minimum detection limits exceed local background concentrations.” (AIP, p.2)
[underline added]
7
EPA’s Look-Up Table Recommendations
From the EPA’s Look-Up Table Technical Memorandum (p.5):
“While DTSC may select LUT values that are equal to the cleanup levels [BTV or MDC], it is USEPA’s understanding that the extraordinarily high decision error rate for laboratory results at or near those cleanup levels is believed unacceptable. In exercising independent technical judgment, as identified in Section 5.2 of the AOC, USEPA recommends an adjustment to the BTVs and minimum detectable concentrations (MDC) to include appropriate consideration for Um [method uncertainty] to ensure an acceptably low decision error rate of 5 percent.” [added definitions inserted and underline added]
8
EPA’s Look-Up Table Recommendations
• Final Radiological Look-Up Table values should be derived using EPA’s BTVs (Background Threshold Values) or future lab MDC (Minimum Detectable Concentrations – for radionuclides with BTVs below the MDC)
and
• Respective BTV/MDCs should be adjusted to address Analytical Method Uncertainty (Um) and Decision Error
9
Analytical Method Uncertainty Each reported sample result exists within range of
possible measurements of a ‘true’ value
10
‘True Concentration’
Range of Measurements at True Concentration
Nu
mb
er o
f M
easu
rem
ents
Concentration
Decision Error For decisions, we specify up front how much error is
acceptable – 5% error means 95% confidence
This approach is consistent with DTSC practice, EPA practice and how cleanups are done across the country
Allows us to know with a greater level of certainty when to stop digging
11
‘True Concentration’
Range of Measurements at True Concentration
# o
f M
easu
rem
ents
Concentration
Draft Provisional Rad Look-Up Table Example - Cesium 137
12
Provisional LUT Value = BTV+ 1.645*Method Uncertainty
BTV = 0.193 (MDC=0.0198) Uncertainty = 10%*BTV = 10%*0.193 = 0.0193 Provisional LUT Value = 0.193 + 1.645*0.0193 Provisional LUT Value = 0.225
# o
f M
easu
rem
ents
Concentration
Radiological Look-Up Table Process
13
BTVs or MDCs AOC requires radiological
cleanup levels to include local background levels (BTVs) or
minimum detectable concentrations (MDCs)
LUT Value = BTV (or MDC) + Decision Error Factor (1.645)*Method Uncertainty
Using independent technical judgment
based on science, USEPA recommends
Look-Up Table Process Summary
EPA recommended adjusting the BTV/MDC to account for uncertainty and decision error in the Look-Up Table value
Accounting for uncertainty and decision error is a standard regulatory practice in setting cleanup values
Science defines how to make these adjustments
Adjustments to the BTV/MDC are relatively small increases because the starting levels are small (background)
14
So - Where are we now?
EPA Radionuclide Background Study
EPA demonstration of laboratory capabilities relative to Minimum Detectable Concentrations
Analysis of current laboratory industry capabilities relative to Minimum Detectable Concentrations
EPA has recommended a Look-Up Table development process
DTSC accepted EPA’s recommendations
15
Provisional Look-Up Table Values
Provisional LUT values will be based on EPA BTVs and MDC information from the EPA study, and recent lab responses for the lowest, routinely achievable MDCs
Provisional LUT values are important since they keep the project moving
They allow development draft remedial plans
They allow CEQA and NEPA to proceed
Draft remedial plans will allow a radiological lab to be selected and Final LUT values established prior to cleanup
16
Conclusion
The AOC requires a cleanup to background
The Look-Up Table has to be technically defensible so that DTSC will have a greater level of certainty that the process identifies contamination above background
EPA provided enough information to allow development of Provisional Radiological Look-Up Table values and keep the project moving
17
Next Steps for Look-Up Table Development DTSC to complete evaluation and develop Provisional
Radiological Look-Up Table
Complete Provisional Radiological Look-Up Table in Spring and post to DTSC website
Apply relevant EPA recommendations to develop Chemical Look-Up Table
Next meeting will be on Chemical Look-Up Table
18
Questions
Community Involvement
Monthly SSFL Progress Report via email http://www.dtsc.ca.gov/sitecleanup/Santa_Susana_Field_Lab/
Ongoing Community Meetings/Calendar
Community Notices aka Fact Sheets, Public Notices, E-list, etc.
For questions regarding SSFL and Community Involvement contact
marina.perez@dtsc.ca.gov
20
top related