PROBABILISTIC ESTIMATES OF DOSE AND INDOOR RADON CONCENTRATIONS ATTRIBUTABLE TO REMEDIATED OILFIELD NATURALLY OCCURRING RADIOACTIVE MATERIAL (NORM)
American Petroleum Institute
Foreword
Executive summary
List of figures
List of tables
Glossary
1.0 Introduction
1.1 Background
1.2 Objective and scope
1.3 Study approach and contents of this report
1.4 Radon and radiation dose criteria
2.0 Waste management practices and description of waste
2.1 Waste pits
2.2 Tank batteries
2.3 Land farming sites
2.4 Pipe scale
2.5 Sludge
3.0 Exposure scenarios and pathways
3.1 Screening pathways assessment
3.2 Source scenarios
3.2.1 Remediated pits
3.2.2 Land farming
3.3 Pathway descriptions
3.3.1 Gamma radiation
3.3.2 Indoor radon
3.4 Methodology
3.4.1 General approach
3.4.2 Gamma radiation
3.4.3 Indoor radon
4.0 Results
4.1 Descriptors of exposure
4.1.1 Exposure estimates
4.1.2 Summary statistics
4.2 Incremental gamma radiation doses
4.2.1 Remediated pit scenario
4.2.2 Land farming scenario
4.3 Indoor radon exposures
4.3.1 Remediated pit scenario
4.3.2 Land farming scenario
5.0 Discussion
5.1 Predicted levels
5.1.1 Comparison of predicted exposures to naturally occurring
exposures
5.1.2 Comparison to regulatory guidelines for remediated pit
scenarios
5.1.3 Comparison to guideline values for the land farming
scenario
5.2 Sensitivity
5.3 Uncertainty
5.4 Comparison to predicted doses from other assessments
5.5 NORM survey procedures by oil companies
5.6 Limitation on indoor radon by NORM survey procedures
5.7 Conclusions
References and bibliography
Appendix A: Characteristics of oil-field NORM and management
practices
Appendix B: Derivation of the distributions of Ra-226
concentrations in oil-field NORM
Appendix C: Screening pathways models and calculations
Appendix D: External gamma and radon pathways - probabilistic
method
Appendix E: Brief review of selected assessments
List of Figures
3.1 Schematic representation of potential routes of exposure
4.1 Distribution of predicted incremental gamma radiation doses
(mrem/yr) from remediated pit scenario
4.2 Distribution of predicted incremental gamma radiation doses
(mrem/yr) from land farming scenario
4.3 Distribution of predicted indoor radon levels (pCi/L) from
remediated pit scenario
4.4 Distribution of predicted indoor radon levels (pCi/L) from
land farming scenario
List of Tables
1.1 Radon and radiation dose criteria
4.1 Summary of predicted incremental gamma radiation doses
(mrem/y) for distribution of NORM equal to or below 30 pCi/g
4.2 Summary of predicted incremental gamma radiation doses
(mrem/y) for NORM concentration equal to 30 pCi/g
4.3 Summary of indoor radon levels (pCi/L) for distribution of
NORM equal to or below 30 pCi/g
4.4 Summary of indoor radon levels (pCi/L) for NORM concentration
equal to 30 pCi/g
5.1 Percentage of homes exceeding 4.0 pCi/L as a function of
area at 30 pCi/g
5.2 Probability of detecting a single hot spot at 30 pCi/g by
gamma measurement on a 3m grid spacing using a criterion of
two times background
Presents the concentration limit of 30pci/g Ra-226 in pipe scale and sludge left near the surface of remediated oilfield sites and returned to unrestricted public use.
| Document Type | Standard |
| Status | Current |
| Publisher | American Petroleum Institute |
