CONTAMINATED LAND MANAGEMENT

Environmental Site Assessment

Environmental site assessments (ESAs)

Environmental site assessments (ESAs) are undertaken to investigate potential contamination of environmental media such as soil, surface water, groundwater and air (vapours & gases) at a facility or property, arising from past and/or current activities at the facility or in the surrounding area. ESAs may be conducted for a variety of reasons including site owner/occupier due diligence, Council planning approvals, purchaser, vendor, merger due diligence, or as part of Statutory environmental audits.

Types of ESAs

Preliminary Site investigations (PSIs) generally involve a desktop investigation, including a review of historical and current land uses and activities as well as EPA public registers to assess the potential for land contamination to be present.

A Detailed Site Investigation (DSI) involves intrusive works to investigate the nature and extent of contamination and potential risk to human health and the environment.

Soil contamination

Soil contamination can arise when:

It has been mixed with waste material
It has been mixed with soil from an unknown origin (i.e. imported fill material)
Impacted from activities where former uses including industrial, commercial, mining or agricultural activities have occurred on-site
Manufactured chemicals have been applied to the material

Typical contaminants that can contribute to soil contamination include:

Specific soil sampling activities undertaken and managed by Helia EHS include:

Underground service location referencing Dial Before You Dig (DBYD) and using underground service detection methods
Non-destructive digging
Soil boring using manual and mechanical drill rig
Test pitting
Trenching
Stockpile management
Reinstatement of opened ground
Soil disposal
Soil remediation
Sourcing and clearance for “clean fill” introduced to site

Surface Water Contamination

Surface water contamination can occur through surface runoff, discharge directly into a waterway or from an up-gradient source of contamination.

Surface water monitoring is useful to:

Assess land use impact
Assess source point impact
Assess surface water quality
Identify the presence of algae blooms
Monitor contamination across a catchment area
Assess concentration changes over time and identify trends
Assess the effectiveness of rehabilitation

Groundwater contamination

Groundwater quality assessments are necessary to determine the extent of contamination and the risk to environmental and human health. Helia EHS can manage groundwater assessments from the planning to implementation and review phase including:

Implementation and review phase including:

Determining targeted locations for well installations
Supervision of drilling and well installation
Underground service clearance prior to well installation
Determine appropriate drilling method for well installation considering the site geology, the contaminants of concern, quality of core, volume of waste
Determine the appropriate depth of drilling to target the water table
Develop the wells to remove all fines and encourage water flow
Conducting groundwater monitoring events (GME) using a variety of techniques
Reviewing field quality data and chemical analysis
Robust data interpretation and presentation
Groundwater fate and transport modelling

Helia EHS has completed many groundwater investigations and remediation programs to help achieve Clean-Up So Far As Reasonably Practicable (CUSFARP) as part of environmental audits.

Soil vapour contamination

Where soil and/or groundwater has been noted to contain volatile contaminants (e.g. fuels, solvents, etc.) soil vapour may be present and a potential risk may exist to site users or visitors. Depending on the type of contaminant, soil vapours can cause serious acute and chronic health effects if not appropriately managed.

Helia EHS provides the following specialist soil vapour assessment capabilities:

Installation of soil vapour bores – both permanent and temporary
Installation of VaporPin™ sub-slab sampling devices
Installation of monitoring wells for landfill gas migration monitoring
Purging and leak testing of soil vapour sampling points and sample trains using helium and/or isopropyl alcohol
Active soil vapour sampling using vacuum canisters (‘Summa’ or ‘Silonite’ type)
Active soil vapour sampling using sorbent tubes, thermal desorption tubes, etc.
Passive soil vapour sampling (various methods including Waterloo Membrane Sampler™, Radiello®, SKC, etc.)

Contact us to get in touch

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