Using Science to Develop a Sustainable Management Policy forAcid Sulfate Soils in Queensland, Australia

摘要

Coastal acid sulfate soils (ASS) are wetland soils and unconsolidatedrnsediments that contain iron sulfides which, when exposed to atmosphericrnoxygen in the presence of water, form sulfuric acid. ASS form inrnprotected low energy environments such as barrier estuaries and coastalrnlakes and commonly occur in low lying coastal lands as Holocene marinernmuds and sands. When disturbed, the iron sulfides in these soils canrnoxidise and produce large volumes of sulfuric acid (essentially similarrnchemistry to acid rock drainage with mines) resulting in the subsequentrnrelease of toxic levels of iron, aluminium, manganese and possibly heavyrnmetals. This results in detrimental effects on aquatic biota, plants,rnanimals and steel/concrete structures and on human health in thernsurrounding environment.rnThere are an estimated 2.3 million ha of ASS located along 6500 kmrnof the Queensland coastline. In contrast to many mineral sulfidesrnencountered in the mining industry, the pyrite crystals in ASS can be asrnsmall as 2 mm and commonly occur as framboids with extremely largernsurface area per unit mass, substantially increasing their reactivity ifrnexposed to air (oxidation). Highly reactive iron monosulfides can alsornoccur, particularly in drains and shallow lakes.rnMany coastal areas, where some 80 per cent of the population ofrnQueensland reside, are coming under pressure for agricultural and urbanrndevelopment. Construction of canal estates, marinas, housing/industrialrnestates, roads, golf courses, aquaculture ponds, sand/gravel extraction andrndrainage for sugar cane can disturb ASS and release sulfuric acid, whichrnmay then drain into adjacent waterways with heavy rain. As developmentrncontinues to encroach on coastal lowlands, the identification,rnquantification and management of ASS must be addressed as part of arncommitment to the principles of Ecologically Sustainable Developmentrn(ESD). ASS can be successfully managed by adopting best practices andrnfollowing guidelines, but government, community and industry mustrncollaborate to raise awareness, avoid 'hot spots' and develop morerncost-effective solutions.rnScientists led the education and public awareness program showingrninfrastructure and environmental damages arising from ASS inrnQueensland. Using results from mapping and research, they convincedrnpolicy makers, industry and polititians to accept the need for legislationrnfounded on good science. The resulting 'State Planning Policy 2/02:rnPlanning and Managing Development Involving Acid Sulfate Soils'rnidentifies the State's interest in acid sulfate soils. The QueenslandrnGovernment considers that development involving acid sulfate soils inrnlow-lying coastal areas should be planned and managed to avoid potentialrnadverse effects on the natural and built environment (includingrninfrastructure) and human health. SPP 2/02 states where the policyrnapplies and when a development application will trigger the policy. It canrnalso be used to assist local governments in preparing their planningrnschemes under the 'Integrated Planning Act 1997'.rnThe SPP 2/02 comes with a 'State Planning Policy 2/02 Guideline' tornprovide advice and technical information on interpreting andrnimplementing the SPP 2/02. This guideline has legal status in assisting inrnthe interpretation of SPP 2/02. Those seeking more detailed technicalrninformation can now also access the 'Soil Management Guidelines' andrnASS 'Sampling Guideline', available from the Department of NaturalrnResources and Mines website. These are some of a series of chaptersrnbeing developed for the 'Queensland Acid Sulfate Soil TechnicalrnManual'.