Employee Presentation 3-00 - 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 3-00 - p 2

Overview – The ChallengesOverview – 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

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DIOXINS – What can they do?DIOXINS – What can they do?

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Viktor Yuschenko - President of UkraineViktor 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

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Background – The SiteBackground – 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

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Background - HistoryBackground - 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

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Site Layout – up to 1990Site Layout – up to 1990

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Site Layout Prior to ClosureSite Layout Prior to Closure

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DandenongEcoindustrialPark

DandenongEcoindustrialPark

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Dioxins – What are they?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

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Dioxins – What are they?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.

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Dioxins – What are they?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)

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Dioxins – What are they?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

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NEHF 2003 - Fitzgerald on TEFsNEHF 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)

TEFs for Dioxins/Furans WHO 98TEFs for Dioxins/Furans WHO 98

Dioxin/Furan TEF

TCDD 1

PeCDD 1

PeCDF 0.5/0.05

HxCDD/CDF 0.1

TCDF 0.1

HpCDD/CDF 0.01

OCDD/CDF 0.0001

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Employee Presentation 3-00 - p 19

2005 WHO Re-evaluation of TEFs2005 WHO Re-evaluation of TEFs

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Background and the National Dioxin Program 2001-2004Background 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)

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Initial Site Risk Based Soil Concentrations 2001Initial 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

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Recommended Dioxin RBSCs 2002-2005 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!

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Distribution of Dioxins – Infrastructure, Lagoons & Irrigation SystemDistribution 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.

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Framework for RemediationFramework 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?

Dioxin Analysis QADioxin 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

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Residential Area – Problems with DataResidential 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!

Relationship of OCDD x TEF to TEQRelationship 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)

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Residential Data / NE Paddocks DataResidential Data / NE Paddocks Data

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The MechanismThe 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!

Mechanism contdMechanism contd

Sediment filled fissure

Clean up in progressClean up in progress

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CALM ConstructionCALM 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?

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Employee Presentation 3-00 - p 41

AcknowledgementsAcknowledgements

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