Acid Sulphate Soils Guideline

Draft Identification and investigation of acid sulfate soils and groundwater

Introduction
Investigations
Using Lab Results
Groundwater
Further Information
References
App. 1: Risk Map
App. 2: Indicators
App. 3: Soil pH

App. 4: Action Criteria

Acid Sulfate Soils Guideline Series

Draft Identification and investigation of acid sulfate soils and groundwater

1.0 Introduction

The early identification of acid sulfate soils can provide a useful platform for developing and adopting effective measures to reduce the generation of acidic soils and water. Acid Sulfate Soils (ASS) are soils that contain iron sulfides which, when drained or disturbed, produce sulfuric acid and result in the release of soluble iron, sulfate, aluminium and other toxic metals. These soils commonly have a pH of between 4 and 6, and have the potential to produce acid if exposed to oxygen.

Proponents proposing to carry out developments that involve the disturbance of soil or the change of groundwater levels in areas susceptible to ASS, should require to conduct a preliminary site assessment and investigation to determine whether or not ASS are present. Inappropriate management of ASS by landowners or developers can result in environmental harm and the risk of litigation under the Environmental Protection Act 1986. Potential impacts from disturbing acid sulfate soils can be found in the draft DEWCP and EPA guidance on managing acid sulfate soils (2002), available on the webpage www.environ.wa.gov.au.

2.0 Purpose of the Guidelines

The purpose of these guidelines is to provide information on the level of investigation required to:

identify the presence or the absence of ASS in areas to be disturbed by a proposed development; and if present,
define the location of ASS and the maximum amount of existing and potential acidity in order to determine appropriate management measures.