The project area served as a waste burial ground from the 1940s to the 1960s, containing sediment from neutralisation ponds, concrete, rocks, plastic, and soil buried to a depth of 2 meters. The primary contaminant of concern was lead, posing a potential threat to groundwater.
In 2005 and 2006, Environmental Earth Sciences conducted a comprehensive contamination assessment of the site, covering both soil and groundwater. These assessments revealed that the majority of contamination stemmed from the buried fill materials. Leachability testing indicated the potential for lead to leach and migrate into the groundwater.
Given the site's non-Statutory Environmental Audit status, the cleanup requirement adhered to standards suitable for sensitive recreational and open space use. The Independent Environmental Reviewer (IER) played a crucial role throughout the entire remediation and validation process. Importantly, a collaborative and constructive working relationship developed between the client, IER, and the EES team.
Our proposed remediation approach to Orica was aimed at lead stabilisation, thereby reducing the leaching potential of the lead contaminant. This involved excavating the fill material, approximately 4,000 cubic meters in total, and processing it through our unique Mobile Unit for Soil Treatment (MUST). Specific chemicals were added during this process to facilitate the formation of naturally occurring lead-based minerals.
Excavations reached depths of up to 2 meters below ground level. Most excavations took place in open paddock areas with ample manoeuvrability, making Occupational Health and Safety (OH&S) measures for dust and sediment control critical. Furthermore, community consultation played a significant role in the project's execution, with regular newsletters disseminated throughout its duration.
The comprehensive remedial works, validation processes, groundwater monitoring, and reporting were successfully completed within a remarkably efficient four-month timeframe. Additionally, substantial savings were achieved in landfill fees since the material was charged at the highest landfill rate.
The Environmental Earth Sciences International Group acknowledges the Traditional Custodians of country throughout Australia and their connections to land, sea and community. We pay our respect to their Elders past, present and emerging and extend that respect to all Aboriginal and Torres Strait Islander peoples today.
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