Incorporating Risk Assessment into an Emergency Spill Response Part Two

Transcription

1 Incorporating Risk Assessment into an Emergency Spill Response Part Two Presented at RemTech 2015 Banff, Alberta Tania Noble October 16, 2015

2 Outline We know our problem what s next? Establish remedial objectives Select the ideal approach Support the approach Monitor and confirm

3 Establish Remedial Objectives Reduce contaminants to levels that protect the environment Minimize additional impacts to the environment 3

4 Risk Assessment and MNA RA will: Evaluate the level of protection required for human and ecological receptors Reduce the need for environmental disturbance Determine appropriate site specific target levels (SSTLs) MNA will: Assess if remediation targets will be reached through regular monitoring and sampling

5 Risk Assessment Generic Approach Risk Based Approach Data Evaluation: Screening for CoCs Remediation Meets Screening? no Select Approach Evaluate Human & Ecological Risks yes Establish Site-Specific Targets no No further assessment Plan meets risk targets? Develop/Modify Risk Management Plan/ Revise Approach yes

6 Risk Assessment Consisted of Multiple Lines of Evidence: Literature Review Human health modeling Ecological health modeling Ecological health studies Wetland health study Biotreatability study Ecotoxicity study Aquatic habitat study 6

7 Human Health Assessment Source Media Exposure Pathway Receptor Soil NA NA Groundwater NA NA Surface water NA NA No unacceptable human health risks related to exposure to CoCs at the Site SSTLs not required for the protection of human health (worker or First Nation community members) 7

8 Ecological Health Assessment 8

9 Ecological Health Studies - Wetland Initial assessment in 2013 assessed the effects of the oil released and the second assessment in 2014 evaluated changes over one growing season

10 Ecological Health Studies - Wetland Signs of dead or stressed vegetation were 10%-20% or less of sampled plots Limited to stressed/dead leaves and a few dead white birch

11 Ecological Health Studies - Biotreatability Biodegradation assessment of PSC completed by National Research Council to characterize microbial population and measure degradation

12 Ecological Health Studies - Ecotoxicity Completed ecotoxicity study in 2014 to assess vegetation growth and invertebrate survival in soils with varying contaminant concentrations Completed earthworm avoidance test by exposing earthworms to impacted and non-impacted soil 12

13 Ecological Health Studies - Ecotoxicity No biological response in lake substrate resulting from exposure to PHC Adverse effect of PHC exposure in ROW soils for plants and earthworms avoided, but no significant effect on collembola Adverse effect in fen substrates in six of seven biological responses Established no-observable effects concentrations as SSTLs 13

14 Ecological Health Studies - Aquatic Habitat Completed benthic sampling program in August 2014 to assess benthic populations and hydrocarbon concentrations in the sediment August

15 Ecological Health Studies - Aquatic Habitat 15

16 Ecological Health Studies Aquatic Habitat Comparison of Benthic Indices (Corrected for Water Depth) with Petroleum Hydrocarbons F1-F4 (Corrected for TOC): Corrected Species Abundance

17 Ecological Health Studies - Conclusions Potential risk to Mallard Duck who lives in the fen area 100% of the time Potential risk to terrestrial plants and invertebrates Potential risk to aquatic plants and benthic invertebrates Derived SSTLs for soil and sediment ROW soil 2,367 mg PHC F2+F3/kg Fen soil 15,551 mg PHC F2+F3/kg Sediment 2,600 mg PHC F1-F4/kg 17

18 Overall Risk Assessment Conclusions Human health assessment no issues Ecological health assessment potential risk Wetland study small % of stressed and dead vegetation Biotreatability study PHC will degrade Ecotoxicity study no effects concentrations established Aquatic health study no effects measured 18

19 Monitored Natural Attenuation Program Groundwater monitoring and sampling program (MNA) Degradation sampling program and nutrient chemistry level within fen Groundwater results indicate that MNA is ongoing based on decreasing trends in contaminant concentrations 19

20 Next Steps 2015 Workplan: Additional groundwater monitoring and sampling program to support MNA Degradation sampling program to determine hydrocarbon reduction Wetland health study follow up to assess vegetation recovery and soil assessment to determine if vegetation effects are linked to remaining impacts in the soil Update RA with 2015 data 20

21 Acknowledgements Enbridge Pipelines Focus Wildlife Owens Coastal Consultants SWAT Consulting Sequoia Environmental Remediation Trimedia Ketek Group Challenger Geomatics National Research Council Maxxam Analytics Barry Zajdlik Stantec staff across Canada and US (over 25 offices) 21

22 Discussion and Questions Heading with Feature Photo Bullet List 1, Arial Regular 28/32 pt. dolor iti blan enim iuscilisl estrud nibh ea consequat. Bullet List 2, Arial Regular 24/28 pt. verosto do dolobor blan enim iuscilisl estrud nibh ea consequat. 22 October 2013