The Challenges for an Environmental Audit of Dioxin

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

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

DIOXINS – What can they do?

Viktor Yuschenko - President of Ukraine n n n n September 2004 – Poisoned with TCDD during Ukraine Presidential elections Elected President October 2004 1000 to 6000 x population background concentration found in his body 50, 000 x 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

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

Background - History n Dioxins detected - 1992 n Site closed and fenced -1996 n EPA serves Pollution Abatement Notice - 1996 n Many Assessments during mid to late 1990 s n Development of EIP by Golder - 2000/01 n Environmental Auditor appointed - 2001 l Human Health Risk Assessment for Dioxins l Established Acceptance Criteria for Residential, Open Space, and Commercial/Industrial Land Uses

Site Layout – up to 1990

Site Layout Prior to Closure

Dandenong Ecoindustrial Park

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

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.

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)

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

NEHF 2003 - 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/Furan TEF TCDD 1 Pe. CDF 0. 5/0. 05 Hx. CDD/CDF 0. 1 TCDF 0. 1 Hp. CDD/CDF 0. 01 OCDD/CDF 0. 0001

2005 WHO Re-evaluation of TEFs

Background and the National Dioxin Program 2001 -2004 n Soil – 104 samples across Australia - 27 from industrial locations n Results: l Max TEQ 98 - in Urban Environment = 42 ng/kg l Average = 6 ng/kg l Max TEQ 98 - Industrial Areas = 11 ng/kg l Average = 2. 7 ng/kg However: n Background soil TEQ 98 initially adopted at DTP l 50 ng/kg (based on 4 samples)

Initial Site Risk Based Soil Concentrations 2001 WHO 98 TDI (pg/kg/day) 1 2 4 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 RBSC TEQ ng/kg: NHMRC 70 pg/kg/month or 2. 3 pg/kg/day TEQ as TDI Child Res = 100 ng/kg

Recommended Dioxin RBSCs 2002 -2005 2003 – EPA Request - Adjusted TDI for Background and consumption of Eggs l NZ data – 0. 5 pg/kg/day 2005 – en. Health advice on Background l 0. 5 to 1. 25 pg/kg/day and in 2005 - WHO changed the TEFs!

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.

Framework for Remediation n n n n On-site Containment – Capped and Lined Mound (Ca. LM) Long period of uncertainty waiting for Works Approval Remove sludges and contaminated soils to Ca. LM Pre-validate paddocks on 50 m 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 Ca. LM Closure? 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 370 ng/kg (open space) as clean-up target for commercial areas (conservative) l individual concentrations up to 900 ng/kg

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. 5 x site criterion; but l 95%UCL well within Res. criterion (64 ng/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. 5 m 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)

Residential Data / NE Paddocks Data

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

CALM Construction n >600, 000 m 3 of contaminated material n Potential conflict of interest 53 V 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?

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 Mc. Connell; Chris Mc. Auley; Kim Shearman; Mitzi Bolton; Kapila Bogoda The URS Audit Team – Ken Mival – Auditor with Jacinta Mc. Innes; Phil Bayne; Cybele Heddle; Emma Hellawell; Peter Mc. Gowan; Iain Cowan; Melissa Harris and Dana Windle