Contaminated Sites and Environmental Remediation

Transcription

1 Contaminated Sites and Environmental Remediation Larkin Kee (nee Mosscrop) Joint Presentation for WiN (Eastern Ontario Chapter) and CNS (Chalk River Branch)

2 Outline Overview of Contaminated Sites Contaminants of Concern Environmental Concerns Environmental Remediation technologies and techniques Hanford Site Canadian Remediation Success Stories

3 Contaminated Sites What is a contaminated site? A site at which substances occur at concentrations (1) above background (normally occurring) levels and pose or are likely to pose an immediate or long term hazard to human health or the environment, or (2) exceeding levels specified in policies and regulations

4 Contaminants of Concern Petroleum hydrocarbons Oxygen depleting substances Toxic organics Nuisance substances BTEX (benzene, toluene, ethylbenzene, and xylene) Polycyclic aromatic hydrocarbon Microorganisms Metals, metalloids, organometallic PCBs Pesticides, herbicides Halogenated hydrocarbons Isotopes Energetics Biological/Chemical warfare agents

5 Radioactive Contamination has a Public Image Problem Radioisotope contamination is one of the only types of contamination which improves through time (decay) Immediate danger to life and health Radioactivity is not always the worst part of a contamination problem Easy to detect on site Radiation is scary... NEED

6 Environmental Concerns Mixed hazardous wastes Chemical compatibility Volume of waste Leaching from waste disposal sites

7 Hazardous Wastes Toxicity Gram for gram cyanide is much more toxic than plutonium when ingested More difficult to detect Immediate danger to safety Compatibility Chemical disposal, in the past, lead to explosions and production of noxious gases Chemicals can combine to make a worse product

8 Leaching- Plume Generation Shallow burial of radioactive or mixed wastes containing radioactive isotopes, metals, chemicals, organics Evidence suggests that even state-of-the-art landfills will eventually leak Mixed waste plumes may spread faster

9 Contaminated Site Concerns Radioactive waste and contamination as well as many more common environmental problems Nuclear sites are not alone in the struggle to deal with hazardous waste and environmental contamination Canadian Program for clean-up of hazardous waste sites- Federal Contaminated Sites Action Plan (FCSAP), United States- Superfund Sites Decommissioning and Waste Management

10 Environmental Remediation What happens once a contaminated site has been identified and action is required?

11 Environmental Remediation Plan Determine the Contaminants of Concern (COC) Evaluate possible remediation options Goal of environmental remediation activities: timely and progressive reduction of hazard and eventually the removal of regulatory control Remediation should be aimed at reducing existing exposures and averting the potential for prolonged exposures to occur in the future. Remediation should [IAEA-2003]: Reduce the doses to individuals or groups of individuals being exposed; Avert doses to individuals or groups of individuals that are likely to arise in the future; Prevent or reduce environmental impacts from the radionuclides present in the contaminated site

12 Major Factors Future land use Public perception and acceptability Regulations Technical considerations Available techniques and technologies Financial capability Waste management Potential human health and ecological impacts

13 Basic Planning Approaches Monitored non-intervention Containment of blocking pathway(s) Source removal

14 Technologies and Techniques Remediation to address Environmental Contamination

15 Monitored Non-Intervention Natural Attenuation Natural processes of retention (sorption), retardation (physical, chemical and biological), and radioactive decay Do Nothing - Baseline option in any remediation case Advantage Cheapest option Limited waste production Disadvantage Slower clean-up Creation of transformation products More costly site characterization

16 Containment or Blocking Pathways Physical barriers and liners Surface Barriers- intended to minimize surface water infiltration and direct contact In-situ barriersconstructed below ground level to contain contaminated material

17 Landfill Capping

18 Plume Mitigation Permeable Reactive Barrier (PRB) Chalk River Laboratories, Chalk River ON Rocky Flats Environmental Technology Sites, Golden CO Y-12 Site, Oak Ridge National Laboratory

19 Source Removal Excavation and retrieval Excavation Contamination Control

20 Groundwater Contamination Pump and Treat TCE contamination, Valcartier QC VOC contamination, Brookhaven National Laboratory NY

21 Remediation- Evaluation Criteria of Approaches and Techniques Effectiveness in remediating the contamination; Ease of implementation Cost associated with the remediation programme; Occupational safety and health risks associated with the technology; Potential secondary environmental impacts (collateral damage); Prior experience with the application of the technology; Socio-economic considerations.

22 Hanford Environmental Remediation Case Study

23 Hanford History Plutonium production in support of America s defense program Weapons production processes left solid and liquid wastes that posed a risk to the local environment including the Columbia River 1989 U.S. DOE, EPA and Washington State Department of Ecology entered into an agreement to clean up Hanford (Triparty agreement)

24 Contaminant Plumes

25 and Burial Grounds Operational Waste generated from 300 Area (developing and manufacturing reactor fuel, research on Pu production) Very large trenches Characterization and remediation challenges

26 Remediation at

27 200 Area Three regions associated with 200 Area (200 East, 200 West, 200 North) Main function was to remove the Pu from uranium fuel rods Five massive processing facilities called canyons

28 200 Area West- Pump and Treat Operated to capture and treat contaminated groundwater to remove chemical and radioactive COCs

29 Canadian Nuclear Contaminated Sites Success Stories

30 Success Stories Nuclear Legacy Liabilities Program Waste Management Area Assessment and Remediation Programs Glace Bay Remediation Project

31 ... The next 30 years...