Reviews guidance (and the lack thereof) on LFG, Ground Gas and Soil Vapour Intrusion and postulates the need for such guidelines to be developed for Australia.

1. Landfill and Ground-Gases –
VOCs and Vapour Intrusion –
The Assessment and Management
of Gas Contamination in Australia
Peter Gringinger & Anthony Lane
EcoForum 2010, 23-24 February 2010, Sydney

2. Contents
• Why bother about Landfill Gas (LFG), Ground Gas
(GG), VOCs and Soil Vapour Intrusion (SVI)?
• Sources, pathways, receptors & risks of GG & SVI
• Current guidance on GG and SVI in Australia (?)
• Development and status of guidance in UK and
North America
• GG and SVI assessment as part of the LCM cycle
• Australian GG and SVI Guidance Framework
• Conclusions

3. Why bother about LFG?
• Cranbourne landfill case, in context of urban
sprawl, demand for housing, brownfields
development

4. Why bother about LFG?
• Cranbourne Landfill LFG CSM

5. Why bother about GG?
• Loscoe, Derbyshire, 1986
• Abbeystead, Lancashire, UK 1984

6. Why bother about VOCs and SVI?
• Barkley Street Case, Brunswick
• Redfield, Colorado

7. Why bother about VOCs and SVI?
• Endicott, Upstate New York

8. “Hypothetical” Case GG
Former Landfill
1960s-1970s
Proposed
Residential
Development

9. “Hypothetical” Case SVI
Possible
Sources for SVI
Primary
School
Car Dealership
Service Station

10. Sources, pathways, receptors &
risks of GG and SVI (CSM)

11. Sources and Risks of GG
• Landfills
• 1990s and 2000s: Moderate to very high (but
mostly lined and controlled)
• 1960s to 1990s: Moderate to very high risk
• <1960s: Low to moderate
• Fill (with high organic content), foundry sands,
sewage sludge: Low to moderate
• Coal mine workings: Low to high
• Peat and coal measures: Low

12. Sources and Risks of SVI
• Service Stations and Drycleaners: High
• Workshops and small factories: Moderate to
high (incl. bakeries, engineering shops etc)
• Petro-chemical industry: Very High
• Landfills: Low to High
• NOTE: Organic sources and plumes can emit methane due to
biodegradation (i.e. 1mg/L of CH4 in GW could result in up
to 4% in soil vapour but flow rates likely low)

13. Current guidance on GG and SVI in
Australia
• EPA Vic Pub 722 – Reduction of GHG from
Landfills (?)
• EPA Vic Pub 788 – Siting, Design, Operation
and Rehabilitation of Landfills
• EPA SA – Env Mgmt of landfill facilities
• EPA NSW Technical Note on VI
• Revised NEPM? (noting that VI criteria for
Petroleum Hydrocarbons will be included)

14. Overseas Guidance on GG – UK
• Developed over last 25 years after incidents in 1980s
• Mature guidance, regularly updated, extensive practical
experience
• GG assessments are required and integral part of LCM
cycle and development policies (planning, building,
environmental regulations)
• Main Guidance documents
• Construction and Industry Research and Information
Association – CIRIA C665, 2008 and C682 (SVI), 2009
• British Standard BS8485: 2007
• National House-Building Council NHBC 2007
• (Ground Gas Handbook, 2009)

15. GG Assessment Approach (UK)
• Initial Desk Study (Phase 1) with CSM on sources,
potential pathways, receptors critical (including good
knowledge of Geology & Hydrogeology) & initial
screening
• Intrusive assessments (Phase 2)
• Detailed soil (organic material) descriptions
• TOC/DOC & gas generation tests
• Gas monitoring wells
• Spacing depends on gas risk and sensitivity of end use
• Bore installation determined by CSM (i.e. permeable
strata)
• Periods and frequency of monitoring determined by gas
risk and sensitivity of end use (range from 4x1 to 24x24)

16. GG Risk Assessment Approach (UK)
• Tier 1: CSM & S-P-R approach and likelihood and
consequences (i.e. similar to AS on Env RA) and can
include generic screening criteria
• Tier 2: Qualitative Assessment for CH4 and CO2
• Gas screening value (GSV) = Borehole flow rate x
gas concentration (%)
• GSV determined risk classification (NHBC or CIRIA)
• GSV determines scope of protection measures
(types, design, construction & validation)
• Tier 3: Quantitative Risk Assessment for high risk
cases using fault tree analysis, models, continuous
gas monitoring (e.g. Gasclam – www.gasclam.co.uk )

17. GG Risk classification & Mitigation

18. SVI Guidance Approach (US/UK)
• Can largely be based on ASTM, ITRC, USEPA &
CIRIA guidance (and few others) and include
phased and tiered risk based approach (see GG)
• Sources, transport and pathways of VOCs may differ
to GG (VOCs are complex from a process
perspective)
• Hence CSM’s account for this and in detailed
investigations (e.g. bore locations, screen depths,
screen lengths, use of multilevel installations etc)
• Mitigation measures largely similar to GG (with
differences in detailed design; e.g. resistance of
barriers against VOCs)

19. SVI Guidance Approach (US/UK)
• Preliminary Risk Assessments (Tier 1) use Soil
Guidance Values for Groundwater and/or Soil
Vapour data (few jurisdictions)
• Generic Risk Assessments (Tier 2) for SVI rely
either on Attenuation Factors (AF between sub-
surface and indoor air vapour concentrations) to
determine risk levels or generic vapour transport
models (i.e. most commonly the Johnson &
Ettinger (1991) model)
• Detailed Risk Assessments (Tier 3) use site
specific models, numerical models, indoor air
data etc

20. Australian Framework Guidance to
GG and SVI Assessment and Mgmt
• Integrate with existing guidance (i.e. NEPM) and
consideration from start of assessment process
• Use phased and tiered risk based approach
• Emphasise use of CSM and S-P-R approach
• Use of GSV and AF plus models*
• Reference to best available UK/US guidance for assessment
to provide technical details
• Has to be an iterative multiple lines of evidence approach
• Include comprehensive coverage of mitigation and
management measures (including design, construction and
validation)
• Who to develop? – e.g. CRC CARE, CSIRO

21. Australian Framework Guidance to
GG and SVI Assessment and Mgmt
Figure 1. The Process of Managing Risks Related to Hazardous Ground Gases
• Staged Assessment Site Characterisation
Define the context & set the objectives
Assessment of Risk
Review data
Determination / Validation
of Remediation
Identify remedial
• Site Assessment
objectives to mitigate
unacceptable risks
Carry out Phase One Desk Study
Is data reliable? Identify feasible remedial options
(e.g. appropriate No
response zones,
• Desk Study (Screening)
variable/ unrepresentative Undertake
Develop initial conceptual site model
groundwater levels)
& undertake preliminary risk assessment additional
intrusive
investigations
Yes
• Intrusive Investigation
No
Has monitoring
been carried out
Has development of model under varying Undertake
included site specific factors No conditions likely additional Has sufficient
that may influence to influence the gas intrusive data been
• Monitoring & Sampling
gas/vapour regime vapour regime? investigations obtained to allow No
and/ or the selection/ design
ITRC, 2007 Yes monitoring of appropriate
& sampling remedial
solutions?
Yes Results sufficiently No
• Data Assessment
consistent/ reliable?
No
Have these factors
identified the
potential presence
of gas/vapour?
ASTM E2600
SVI
CIRIA C682
Yes
Source(s) of
gas(es)/ vapour(s)
No
Yes
Detailed evaluation of remedial
options
• CSM CIRIA C665
identified?
SVI
Develop a remedial strategy
Yes
Yes
SVI Extent of
source(s) established?
No Design, implementation &
verification of
remedial measures
• Risk Assessment GG
No Are there potential Yes
unacceptable risks?
Refine conceptual site model
Review/
No Is post installation/
amend
construction
Consider odour & toxicity and remedial
• Tier 1, 2 and 3
monitoring required?
incorporate strategy
Yes into risk assessment as appropriate
Yes
Identify further actions to clarify
potential unacceptable risks Undertake appropriate risk
Undertake post installation/
• Mitigation Design &
assessment modelling. Define gas
regime construction monitoring
Establish objectives of any
further investigations
Green Amber Red
Is the monitoring No
Implemention
Carry out further investigation data acceptable?
[desk based/intrusive/ Monitoring]
Does risk
No assessment
demonstrate Yes
corrective action
required? Completion/Validation Report
• Verification
Yes
NO FURTHER NO FURTHER NO FURTHER
ACTION REQUIRED ACTION REQUIRED ACTION REQUIRED

22. Australian Framework Guidance to GG and
SVI Assessment and Mgmt
(Potentially) Contaminated Site
• Site History (on- & offsite)
• COPC’s (Gases and VOCs)
Preliminary (GG/SVI) Site Assessment • Initial CSM & preliminary RA
(Desk Study & Walkover)
• Work Plan based on CSM
• Intrusive Investigation
Site Investigation • Monitoring Program
• Collate Data
Data Analysis • Analyse & Review (incl QA/AC)
• Refine CSM
• Include odour and toxicity issues
Risk Assessment • Tier1: Generic guideline levels
• Tier 2: GSV or AF & generic models
• Tier 3: Site specific DQRA
Risk Mitigation and Remediation
•Remedial Objectives
• Options Screening & evaluation
• Remedial Strategy
Site Close Out • Design, implement & verification
• Monitoring and Validation

23. Conclusions
• Not only landfills produce ground gases
• Not only servos and drycleaners have SVI issues
• GG and SVI issues are common
• It’s the Geology (pathway) stupid
• Hence know your CSM and S-P-R (stupid)
• Phased and tiered Risk based Assessment
• Integration of GG and SVI from start of Land
Contamination (just like soil and GW) Assessment
• Mitigation and Mgmt details are part of the deal
• National guidelines needed (to avoid another
Cranbourne) & minimise litigation potential

24. References and Links
• CIRIA, 2007: Assessing risks posed by hazardous ground gases to
buildings, C665.
• CIRIA, 2009: The VOCs Handbook, Investigating, assessing and
managing risks from inhalation of VOCs at land affected by
contamination. C682.
• Wilson, S.; G. Card & S. Haines, 2009: Ground Gas Handbook.
Whittles Publishing, UK.
• ASTM, 2008: E2600-08 Standard Practice of Vapor Intrusion into
Structures on Property Involved in Real Estate Transactions.
• British Standard, 2007: BS8485:2007 Code of practice for the
characterization and remediation from ground gas in affected
developments.
• NHBC, 2007: Guidance on Evaluation of Development Proposals on
Sites where Methane and Carbon Dioxide are Present. Report
Edition No. 04, March 2007.

25. References and Links
• API, 2005. Collecting and Interpreting Soil Gas Samples from the
Vadose Zone, A Practical Strategy for Assessing the Subsurface Vapor-
to-Indoor Air Migration Pathway at Petroleum Hydrocarbon Sites.
Publication No. 4741.
• EPRI, 2005. Reference Handbook for Site Specific Assessment of
Subsurface Vapor Intrusion to Indoor Air. March 2005.
• ITRC, 2007: Vapor Intrusion Pathway: A Practical Guide. Technical and
Regulatory Guidance, January 2007.
• CALEPA/DTSC, 2004. Guidance for the Evaluation and Mitigation of
Subsurface Vapor to Indoor Air, Interim Final, December 2004.
• CALEPA/DTSC, 2009. Vapor Intrusion Mitigation Advisory. April 2009.
• USEPA, 2008: Brownfields Technology Primer: Vapor Intrusion
Considerations for Redevelopment. EPA/542/R-08-001, March 2008.
• USEPA, 2008. Engineering Issue: Indoor Air Vapor Intrusion Mitigation
Approaches. EPA/600/R-08-115, October 2008.
• USDOD, 2009. DoD Vapor Intrusion Handbook. January 2009.

26. References and Links
• NYSDOH, 2006. Guidance for Evaluating Soil Vapor Intrusion in the
State of New York. October 2006.
• USEPA, 2002. OSWER Draft Guidance for Evaluating the Vapor
Intrusion to Indoor Air Pathway from Groundwater and Soils
(Subsurface Vapor Intrusion Guidance). EPA/530/D02-004, November
2002.
• USEPA, 2005. Guidance for Evaluating Landfill Gas Emissions from
Closed or Abandoned Facilities. EPA/600/R05-123a, September 2005.

27. References and Links
• Clu-In Vapor Intrusion Focus Area www.clu-
in.org/issues/default.focus/sec/Vapor_Intrusion/cat/Overview/
• EnviroGroup Vapor Intrusion Links
www.envirogroup.com/links.php
• Indoor Air Vapor Intrusion Database iavi.rti.org/
• ITRC Vapor Intrusion Site
www.itrcweb.org/teampublic_Vapor.asp
• The Landfill Gas Expert www.landfill-gas.com/

28. GG Training
• ACLCA Vic is planning a 4-day short course on
“Landfill Gas investigation, risk assessment
and remediation” some time between July to
September 2010
• Watch for details on www.aclca.org.au