WHAT IS REMEDIATION?

Land remediation is the process of restoring land to a standard that protects the environment, human health, or buildings.

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Land remediation often entails the removal of pollutants or contaminants in soil, surface water, and ground water. It can also include more complex types of land remediation where the contamination remains in the ground but is stabilised through some means.

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Since its inception, the Macquarie Point Development Corporation has been tasked with remediating the 9.3-hectare site known of as Mac Point.

The Australian Government granted the Tasmanian Government $45M in 2012 to undertake the remediation process, which at the time was acknowledged would take several years to complete due to the significant amount of contamination in the ground.

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For almost 200 years, Mac Point has been used as a farm, an abattoir, lumber yard, a gas works, cold store, goods storage, for heavy industry, rubbish disposal, the military, freight, and rail. As a result, the site’s soil and ground water has been heavily polluted over time with a combination of fuels, heavy metals, and other contaminants.

 

WHY IS THERE CONTAMINATION?

Since colonisation, Mac Point has been a place of industrial needs for a growing population, and each time the site has built on what was there before, and then built on again and again, creating layer upon layer of coal and tar, grease and oil and concrete.

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Contaminants found in the ground at Mac Point include:

• Asbestos pipe

• Spent fuel

• Coal tar

• Phosphorus and sulphur

• Heavy metals (arsenic, copper, lead, zinc, etc.)

 

Contaminants found in the groundwater at Mac Point include:

• Heavy metals

• Ammonia

• Cyanide

• E. Coli

• Spent fuel

 

In addition to removing contaminants, almost 1 kilometre of ageing oil and diesel pipelines, once used by industry and the navy over 50 years ago, have been removed.

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To date:

• Nearly 2000 soil samples have been undertaken to map and confirm the removal of contamination

• 67,000 tonnes of contaminated soil have been removed from Mac Point

• 2.3M litres of contaminated ground water has been removed from Mac Point

 

What work has been done?

Remediation work started in 2015 after the appointment of a Project Remediation Consultant and subsequent Environmental Auditor.

This was followed by site investigations to understand the contamination on site, and to date has included:

• Soil investigations, soil bores and test pits at 250 locations across the site

• 588 soil samples were analysed as part of the initial soil profiling and analysis

• 65 groundwater wells on and off site were installed, making a total of 175 ground water monitoring wells on or near the site, with over 273 groundwater samples collected over 9 groundwater monitoring events

• the collection and assessment of 60 soil vapour samples and 27 ambient air samples, to assess if any potential current or future risk to Site users is presented from soil or groundwater impacts

• Removal of approximately 445L of light non-aqueous phase liquids (LNAPLs) from groundwater on site. LNAPLS are organic liquid contaminates such as gasoline, diesel, and other petroleum hydrocarbon products

• A further 1,190 soil samples as part of the remediation work so far, to confirm removal of the contaminated soil.

• A pilot trial is currently being finalised to inform the remediation of the former gasworks

 

What work remains?

The majority of the site has been remediated with two areas remaining:

• a parcel in the south-east corner, where a historic diesel pipe and related contamination require removal

• a parcel in the south-west corner of the site, which was previously a gas works and cold store, and was added to the precinct in 2015, and was outside of the scope of the original funding was provided.

 

Planning to progress these works is underway.