Release of metals during oxidation of pyrite from marine sediments in Malaysia

Pyrite, FeS2, extensively accumulates under saline and brackish-water tidal swamp and marsh. Pyrite is stable under waterlogged (reduced) condition. When drainage brings oxygen into this environment, the pyrite is oxidized releasing sulfuric acid. A study was conducted to determine the release of metals when pyritic sediment was oxidized or exposed to the atmospheric conditions. The pyrite content of sediments was 1.67% and 2.58%, respectively, from Sitiawan and Kuala Linggi. The total Fe and Al of both sediments were very high. Zn and Mo contents in sediments from Kuala Linggi were above the accepted level in soils and sediments (Alloway, 1990). Other metals were in normal range found elsewhere in soils and sediments. Large amounts of metals especially Fe and Al were present in the water soluble form indicating that exposing the sediments rich in pyrite to the atmosphere would release Fe and Al into the environment