Previous International Acid Sulfate Soils Symposia/Conferences took place in Wageningen (Netherlands) 1972; Bangkok, Thailand 1981; West Africa – Dakar, Senegal and Guiné Bissau 1986; Ho Chi Minh City, Vietnam 1992; Tweed Heads, Australia 2002; Guangzou, China 2008, and Vaasa, Finland 2012. None have been held in the U.S., but a two day field tour supported by the international acid sulfate soils working group and SSSA, which traversed primarily Coastal Plain sites in Delaware, Maryland and Virginia took place for World Congress of Soil Science in Philadelphia in 2006. Papers from the first four symposia appeared as publications of the International Land Reclamation Institute, Wageningen. Those of the 5th Conference were published in a special issue of the Australian Journal of Soil Research, whereas those of the 6th
were published a book by the Chinese and those of the 7th
by the Finnish Geological Survey. The term acid sulfate soils came into use for the first symposium by Leen Pons (deceased 2008, called in a book honoring him, the Father of the International Acid Sulfate Soils Symposia/ Conferences) and other organizers. In an initial paper, he proposed that the term “Acid Sulphate Soils be used in the widest sense of the expression. As such this expression pertains to all materials and soils in which as a result of processes of soil formation, sulfuric acids either will be produced, are being produced or have been produced in amounts that have a lasting effect on main soil characteristics”. This broad definition includes potential, active, and post-active acid sulfate soils and soil materials, of which by current tentative plans, examples of all three forms will be shown on field trips for the 8th
Conference. Three field trips are tentatively planned for the 8th
Conference: 1) a pre-conference tour on Sunday, July 17; a mid-conference tour on Wednesday, July 20; and a post-conference tour Friday (and possibly Saturday), July 22 (-23). In a paper at the 1st
Conference, David Rickard described how sulfides accumulate in estuarine soils and sediments from sulfate in sea water and iron from iron oxides by what we now call sulfidization. Rickard, now at Cardiff University in Great Britain continued his lifetime studies and in 2012 published a book to document that many sediments and sedimentary rocks throughout geologic columns contain pyrite accumulated by sulfidization. In another paper at the 1st
Conference, Nico van Bremen, who completed his doctoral dissertation at Wageningen on acid sulfate soils in Thailand, described processes that take place when sulfidic materials
(that he subsequently helped to re-define for Soil Taxonomy
) are exposed to aerobic conditions to undergo what we now call sulfuricization, to form sulfuric horizons
. At the 8th
Conference we hope to honor these and other early acid sulfate soils workers. Previous conferences have emphasized what some call Coastal Acid Sulfate Soils. During the 8thConference we hope to show that acid sulfate soils principles apply to many soils in the U.S. and that engineers and others involved in land disturbance activities and issues need to pay attention.
* Oral paper presented at the 2015 National Meeting of the American Society of Mining and Reclamation, Lexington, KY Reclamation Opportunities for a Sustainable Future June 6 - 11, 2015. R.I. Barnhisel (Ed.). Published by ASMR; 1305 Weathervane Dr., Champaign, IL 61821.