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

Employee Presentation p 3 DIOXINS – What can they do?

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

Employee Presentation p 5 Background – The Site  The former Dandenong Treatment Plant (DTP) transferred to Melbourne Water ownership in 1991  DTP ceased operation in  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 p 7 Background - History n Dioxins detected n Site closed and fenced n EPA serves Pollution Abatement Notice n Many Assessments during mid to late1990s n Development of EIP by Golder /01 n Environmental Auditor appointed l Human Health Risk Assessment for Dioxins l Established Acceptance Criteria for Residential, Open Space, and Commercial/Industrial Land Uses

Employee Presentation p 8 Site Layout – up to 1990

Employee Presentation p 10 Site Layout Prior to Closure

Employee Presentation p 11 Dandenong Ecoindustrial Park

Employee Presentation p 12 Dioxins – What are they? n “Dioxin” generic term for congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) n Apart from pesticide manufacture - they were the unintended by-products of waste incineration and manufacture of other chlorinated hydrocarbons n 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 p 13 Dioxins – What are they? n Can bio-accumulate (some authors say not) n They are lipophilic – (ie absorbed in fat) n Toxic responses include chloracne, carcinogenicity, liver and nerve effects, and adverse effects on reproduction development and endocrine functions n Health effects in humans documented at PPB levels n WHO defined as “known human carcinogen” in 1997.

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

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

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

TEFs for Dioxins/Furans WHO 98 Dioxin/FuranTEF TCDD1 PeCDD1 PeCDF0.5/0.05 HxCDD/CDF0.1 TCDF0.1 HpCDD/CDF0.01 OCDD/CDF0.0001

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Employee Presentation p WHO Re-evaluation of TEFs

Employee Presentation p 20 Background and the National Dioxin Program n Soil – 104 samples across Australia - 27 from industrial locations n Results: l Max TEQ 98 - in Urban Environment = 42ng/kg l Average = 6ng/kg l Max TEQ 98 - Industrial Areas = 11ng/kg l Average = 2.7ng/kg However: n Background soil TEQ 98 initially adopted at DTP l 50ng/kg (based on 4 samples)

Employee Presentation p 21 Initial Site Risk Based Soil Concentrations 2001 WHO 98 TDI (pg/kg/day)1 2 4 RBSC TEQ ng/kg: Commercial Worker Construction Worker Child Recreational Child Residential NHMRC 70pg/kg/month or 2.3pg/kg/day TEQ as TDI Child Res = 100ng/kg

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

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

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

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

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

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

Residential Data / NE Paddocks Data

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

Mechanism contd Sediment filled fissure

Clean up in progress

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

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Employee Presentation p 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