Thioarsenate sorbs to natural organic matter through ferric iron-bridged ternary complexation to a lower extent than arsenite.

Understanding processes regulating thioarsenate (HAsSO; n = 1 - 3; x = 1 - 3) mobility is essential to predicting the fate of arsenic (As) in aquatic environments under anoxic conditions. Under such conditions, natural organic matter (NOM) is known to effectively sorb arsenite and arsenate due to metal cation-bridged ternary complexation with the NOM. However, the extent and mechanism of thioarsenate sorption onto NOM via similar complexation has not been investigated.

Mechanistic Insight into the Abiotic Interactions of Selenate and Selenite with Natural Organic Matter.

Natural organic matter (NOM) decreases the selenium (Se) mobility in soil and sediment. Biotic dissimilatory reduction of selenate and selenite and assimilation of the reduced Se species into biomolecules are thought to be primarily responsible for this decreased Se mobility. However, the possibility of Se immobilization due to the abiotic interaction of Se species with NOM is still poorly understood.