ABSTRACT
The issue of acid sulfate soils (ASSs) and their management must now encompass those landscapes containing sulfidic material, both soft sediments and hard rocks, located on the coast and inland of land masses. In the past 20 years around the world, there has been a marked shift in understanding the necessity of this broader view. This entry covers a large topic and for this reason touches only lightly in some detailed aspects of ASS characteristics and processes. The references will, however, lead readers to more details on many aspects of the subject. In this entry, several concepts and case studies involving policy, regulation, and best practice from Australia are discussed because Australia now probably provides much of the impetus and methods for global adoption of best management practices, which can be applied worldwide. There are three fundamental questions underlying the use of ASS landscapes. Firstly, how best to use the existing environment productively while minimizing any sulfide mineral oxidation. Secondly, how to effectively neutralize any existing or newly created acidity formed during a particular land use. Thirdly, how to eliminate or minimize downstream environmental impacts from ASS drainage waters, which may include deoxygenation of soil or surface waters and the release of metals and nutrients. Therefore, best management of ASS must address these questions
