Partitioning and potential mobilization of aluminum, arsenic, iron, and heavy metals in tropical active and post-active acid sulfate soils: Influence of long-term paddy rice cultivation.

Drainage of potential acid sulfate soils (PASS) for paddy rice cultivation results in the formation of active acid sulfate soils (AASS) and subsequently post-active acid sulfate soils (PAASS). The drainage of PASS causes severe environmental problems including acidification and metal contamination of soil and water resources. This study examined the vertical distribution and partitioning of Al, As, Co, Cu, Fe, Mn, Ni, Pb, and Zn in six tropical acid sulfate soils representing AASS and PAASS under long-term paddy rice cultivation (>145 years).