ACLCA Adelaide Dec 2012 Ken Mival – Senior Principal URS Australia

1. The Challenges for an Environmental Audit of Dioxin Remediation on a Former Sewage Treatment Plant Site ACLCA Adelaide Dec 2012 Ken Mival – Senior Principal URS Australia Employee Presentation 3-00 - p 1

2. Overview – The Challenges • Dioxins – What are they? - Lack of Guidance – and Cost of Analysis • Setting of Health Risk Based Remediation Objectives • Remediation Approach & Post Remediation Issues • Background versus Pollution • Quality Assurance at Very Low Concentrations • Land Development Drivers Employee Presentation 3-00 - p 2

3. DIOXINS – What can they do? Employee Presentation 3-00 - p 3

4. Viktor Yuschenko - President of Ukraine • September 2004 – Poisoned with TCDD during Ukraine Presidential elections • Elected President October 2004 • 1000 to 6000x population background concentration found in his body • 50,000x greater concentration in blood than population • Suffered intestinal and liver damage & massive facial chloracne • 2007/2008 appeared to have improved 3 times faster than expectation (Lancet) • 2010, voted out of the Presidency and still alive in 2012 Employee Presentation 3-00 - p 4

5. Background – The Site • The former Dandenong Treatment Plant (DTP) transferred to Melbourne Water ownership in 1991 • DTP ceased operation in 1996. • 1930s to 1990s received domestic and trade waste effluent for primary & secondary treatment • 1950s to 1990s treated water from trade waste treatment plant flood irrigated on site • Site proposed for redevelopment for commercial (VicUrban Logis) and low density residential use • Public open space remains along creek and wetland Employee Presentation 3-00 - p 5

7. Background - History • Dioxins detected - 1992 • Site closed and fenced -1996 • EPA serves Pollution Abatement Notice - 1996 • Many Assessments during mid to late1990s • Development of EIP by Golder - 2000/01 • Environmental Auditor appointed - 2001 • Human Health Risk Assessment for Dioxins • Established Acceptance Criteria for Residential, Open Space, and Commercial/Industrial Land Uses Employee Presentation 3-00 - p 7

8. Site Layout – up to 1990 Employee Presentation 3-00 - p 8

10. Site Layout Prior to Closure Employee Presentation 3-00 - p 10

11. DandenongEcoindustrialPark Employee Presentation 3-00 - p 11

12. Dioxins – What are they? • “Dioxin” generic term for congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) • Apart from pesticide manufacture - they were the unintended by-products of waste incineration and manufacture of other chlorinated hydrocarbons • Sources include: • Incinerators - burning of plastics (PVC etc); • wood burning stoves; cars and trucks; cigarettes • Pollution from pesticide and chemical manufacture • Forest and grass fires Employee Presentation 3-00 - p 12

13. Dioxins – What are they? • Can bio-accumulate (some authors say not) • They are lipophilic – (ie absorbed in fat) • Toxic responses include chloracne, carcinogenicity, liver and nerve effects, and adverse effects on reproduction development and endocrine functions • Health effects in humans documented at PPB levels • WHO defined as “known human carcinogen” in 1997. Employee Presentation 3-00 - p 13

14. Dioxins – What are they? However: • No uptake into plants but can have airborne deposition on plants (so wash before eating) • Very low water solubility • If in water - tend to stick to solid matter and settle out (so found in sewage sludges) • Very low volatility – do not vaporise remaining bound to particulate matter (so no inhalation) • Bind strongly to soil particles (this limits potential for skin absorption and migration) Employee Presentation 3-00 - p 14

15. Dioxins – What are they? • Epidemiological evidence indicates humans are less susceptible to dioxins than laboratory animals • Rats – observable effects at 1-2ng/kg/day • From Seveso - absorption through skin compared to soil concentrations was low • Dioxins metabolise out of the body over time Employee Presentation 3-00 - p 15

16. NEHF 2003 - Fitzgerald on TEFs • Toxicity Equivalence Factor (TEF) Compares toxicity of congener to 2,3,7,8 TCDD = 1 • Toxicity Equivalence Quotient (TEQ) Sum of all (Concentrations x TEF) = TEQ – quoted as Dioxin Concentration (TEQ) • Typically 17 main congeners analysed and summed • WHO advice in 1998 – (updated in 2005) Employee Presentation 3-00 - p 16

17. TEFs for Dioxins/Furans WHO 98 Dioxin/FuranTEF TCDD 1 PeCDD 1 PeCDF 0.5/0.05 HxCDD/CDF 0.1 TCDF 0.1 HpCDD/CDF 0.01 OCDD/CDF 0.0001

18. Employee Presentation 3-00 - p 18

19. 2005 WHO Re-evaluation of TEFs Employee Presentation 3-00 - p 19

20. Background and the National Dioxin Program 2001-2004 • Soil – 104 samples across Australia - 27 from industrial locations • Results: • Max TEQ98- in Urban Environment = 42ng/kg • Average = 6ng/kg • Max TEQ98 - Industrial Areas = 11ng/kg • Average = 2.7ng/kg However: • Background soil TEQ98 initially adopted at DTP • 50ng/kg (based on 4 samples) Employee Presentation 3-00 - p 20

21. Initial Site Risk Based Soil Concentrations 2001 WHO98 TDI (pg/kg/day) 1 2 4 RBSC TEQ ng/kg: Commercial Worker 20 000 40 000 80 000 Construction Worker 1 625 3 250 7 500 Child Recreational 370 740 1 480 Child Residential 38 76 152 NHMRC 70pg/kg/month or 2.3pg/kg/day TEQ as TDI Child Res = 100ng/kg Employee Presentation 3-00 - p 21

22. Recommended Dioxin RBSCs 2002-2005 2003 – EPA Request - Adjusted TDI for Background and consumption of Eggs • NZ data – 0.5 pg/kg/day 2005 – enHealth advice on Background • 0.5 to 1.25 pg/kg/day and in 2005 - WHO changed the TEFs! Employee Presentation 3-00 - p 22

24. Distribution of Dioxins – Infrastructure, Lagoons & Irrigation System • Sludges all treated as highly contaminated and removed • Irrigation system spread dioxins over levelled paddocks • Higher concentrations closer to irrigation points • Concrete infrastructure demolished and treated as contaminated • All pipelines and drainage channels excavated and targeted validation sampling of remaining soils • Other identified site contaminants assessed mainly with reference to NEPM (1999) Tier 1 criteria. Employee Presentation 3-00 - p 24

26. Framework for Remediation • On-site Containment – Capped and Lined Mound (CaLM) • Long period of uncertainty waiting for Works Approval • Remove sludges and contaminated soils to CaLM • Pre-validate paddocks on 50m grid to identify areas requiring remediation • Validate Lagoons after removal of sludges with 50 m grid • Any exceedences - clean up all four adjacent 50 metre grid squares to nearest compliant locations • Cheaper to excavate than to close down validation spacing • What happens after CaLM Closure? • EPA Guidance? Employee Presentation 3-00 - p 26

27. Dioxin Analysis QA • Extreme care required to avoid cross contamination or systemic errors at very low concentrations • 2 main Laboratories – SGS and ALS • Capacity Issues (around 3000 Dioxin analyses in assessment phase – over 6000 for project) • 50/50 1o/2o so not dependant on just one lab • Systemic differences adjusted – factor applied to lab with lowest concentrations – ie conservative • Errors could also be up to about 70% of TEQ • retained 370ng/kg (open space) as clean-up target for commercial areas (conservative) • individual concentrations up to 900ng/kg Employee Presentation 3-00 - p 27

28. Residential Area – Problems with Data Residential area data were inconsistent: Paddocks not used for irrigation Random hotspots at variable depths Individual concentrations exceed 2.5x site criterion; but 95%UCL well within Res. criterion (64ng/kg TEQ) Assessment stalls – Auditor becomes a mushroom Inspector Clouseau comes up with the answer!

29. Relationship of OCDD x TEF to TEQ • OCDDs dominate at depth • TCDD and other pollution congeners impact mainly on shallow soils down to about 0.5m depth • National Dioxin Program – soils – were also predominantly OCDD – is that background? • Two dioxin populations appear to be present • Can now distinguish between “Local Background” (diffuse source) and “Pollution” (point source) Employee Presentation 3-00 - p 29

30. Residential Data / NE Paddocks Data

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35. The Mechanism • Irrigated areas – kept moist to maintain grass growth for grazing in dry periods • Non-irrigated areas – the clays dry out in summer and crack • 150 plus years of outfall from incinerators, industry and forest fires • Rain washes fallout into cracks • Concentrations at depth but limited lateral extent • Conclusion – ‘diffuse’ concentrations are random and not significant in terms of exposure • Clean up the ‘point’ source dioxins • EPA after discussion agreed Auditor could accept this approach - if HE was satisfied with it! Employee Presentation 3-00 - p 35

36. Mechanism contd Sediment filled fissure

37. Clean up in progress

38. CALM Construction • >600,000m3 of contaminated material • Potential conflict of interest 53V Audit • Construction review only – no input on design • Timing of Cell Construction v Audit and subsequent placement of wastes • Field Testing of Materials – eg Ironstone in Clay • Leachate and Landfill gas post Brookland Greens? Employee Presentation 3-00 - p 38

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41. Acknowledgements Clients: Bill Welsford and Doug Tipping of Melbourne Water For the opportunity and permission to use the material developed for the DTP site in this talk Golder: Darren Watt - For permission to use their information; EPA for their input over 10 years: Cheryl Batagol; Stuart McConnell; Chris McAuley; Kim Shearman; Mitzi Bolton; Kapila Bogoda The URS Audit Team – Ken Mival – Auditor with Jacinta McInnes; Phil Bayne; Cybele Heddle; Emma Hellawell; Peter McGowan; Iain Cowan; Melissa Harris and Dana Windle Employee Presentation 3-00 - p 41