Legislation, policies and risk assessments relevant to acid sulfate soils

The environmental legal system in Queensland requires all people (including corporations and governments) conducting activities that affect the Queensland environment to:

• obtain and comply with any necessary licence, permit or government approval
• comply with any relevant standard imposed by the law, including taking all reasonable and practicable measures to prevent or minimise environmental harm (the general environmental duty)
• notify the relevant authority (generally the authority which issued any relevant licence or approval, or the Department of Environment, Science and Innovation), if unlawful material or serious environmental harm occurs or may occur.

Legislation and policies that apply to acid sulfate soils in Queensland include the Environmental Protection Act 1994, Planning Act 2016 (including the Qld State Planning Policy 2017, State interest – emissions and hazardous activities), Vegetation Management Act 1999, Fisheries Act 1994 and the State Development and Public Works Organisation Act 1971. At the commonwealth level, the Environment Protection and Biodiversity Conservation Act 1999 applies.

Within acid sulfate soil affected areas of Queensland, there is an overall objective to protect the natural and built environment, and human health from potential adverse impacts of acid sulfate soils by:

• identifying areas with high probability of containing acid sulfate soils
• providing preference to land uses that will avoid, or where avoidance is not practicable, minimise the disturbance of acid sulfate soils
• including requirements for managing the disturbance of acid sulfate soils to avoid or prevent the mobilisation and release of acid, iron and other contaminants.

While appropriate planning and development controls can minimise the risks to the environment, avoiding the disturbance of acid sulfate soils is always the preferred strategy. Where avoidance is not possible, at all times the acid sulfate soils must be adequately investigated to determine whether the impacts can be managed to prevent the release of acid, soluble iron and other contaminants to the surrounding environment. This is done via an Acid Sulfate Soils Risk Assessment.

Acid Sulfate Soils Risk Assessment

Projects and activities involving the disturbance of acid sulfate soils must assess the level of risk associated with the disturbance by considering both the on- and off-site impacts. A risk assessment should be a precursor to any proposal with the potential to disturb acid sulfate soils. Determining whether or not acid sulfate soils are present at a site, and managing them appropriately if they need to be disturbed, can involve major costs. These costs may compromise a project’s design or economic viability.  Refer to the Soil Management Guidelines for more information.

An Acid Sulfate Soils Risk Assessment will involve the following:

• a thorough acid sulfate soils investigation in accordance with the latest Sampling Guidelines
• soil analyses according to the latest Laboratory Methods Guidelines
• a groundwater investigation in compliance with the National Dewatering Guidance Material.

The acid sulfate soils and groundwater investigations provide information on the environmental setting, location of and depth to acid sulfate soils, and the amount of existing and potential acidity present in the soil. Successful acid sulfate soils management depends on the results of the investigation—and results of the investigation help to determine the most appropriate management strategy for a site.

Acid sulfate soils management

Following the Acid Sulfate Soils Risk Assessment, site-specific management strategies appropriate to the risk must be documented and implemented. Appropriate environmental management techniques that are consistent with the Queensland Soil Management Guidelines include:

• neutralising existing acidity and preventing the generation of acid and metal contaminants
• preventing the mobilisation and release of acid, iron or other contaminants into surface or groundwater
• preventing insitu oxidation of acid sulfate soils through appropriate groundwater management
• undertaking appropriate treatment before disposal (whether or not that disposal occurs off-site)
• documenting management strategies and reporting requirements in an Acid Sulfate Soils Environmental Management Plan.