An environmental audit of the Woodvale evaporation ponds has found the land could be reused for agriculture over time, despite the presence of toxic materials like arsenic.
The audit, completed by an Environmental Protection Authority appointed company, included soil, air and water sampling at the ponds, which were historically used as a site to store water pumped from mine workings.
Woodvale residents have long-standing environmental concerns with the site, some of which were partially addressed in the report, which found that groundwater, although considered contaminated, was not a risk if managed correctly.
“It is noted that arsenic has not been reported in the groundwater at appreciable concentrations, which indicates that arsenic is likely being adsorbed in the clay liners and shallow sediments beneath the WEPC,” the report read.
The audit does however raise concerns with potentially toxic dust at the site.
Soil at the ponds is said to contain salt and arsenic, according to the audit.
“Observations from my site inspection that there are significant areas of exposed earth/salt which are liable to dust generation during windy conditions and review of the available dust data for this audit indicate that dust accessions are such that there is the potential for off-site risks to arise in the absence of effective management,” the report read.
The audit also noted the risk to foraging animals at the site, which requires “an ecological risk assessment to determine the level of risk, and also to determine an appropriate ecological-based clean up criterion for the rehabilitation of the site”.
The auditor assessed the rehabilitation plan for the ponds, which is a requirement of a work plan held by mining licence holder GBM Gold.
Read more: State government orders ponds closure
Broadly speaking, the auditor was confident in the rehabilitation plan and its capacity to reduce environmental risks at the site, but was wary of a proposal to irrigate crops for agricultural production at the site.
“It is imperative that the need to irrigate is weighed up against the risk associated with the mobilisation of any residual contaminants that remain following remediation and subsequent risks to groundwater,” the report read.
The audit, which acknowledged the limitations and gaps in its data, suggested the ponds, with correct management, can be returned to use for agriculture.