Chemical precipitation and complexation are primarily important for the inorganic species. The formation of coordination complexes is typical behaviour of transition metals, which provide the cation or central atom. Ligands include common inorganic anions such as Cl - , F- , Br - , SO4 2- , PO4 3- and CO3 2- as well as organic molecules such as amino acids. Such complexation may facilitate the transport of metals. Biodegradation is a reaction process mediated by microbial activity (a biotic reaction). Naturally present bacteria may transform the organic molecule to a simpler product, . another organic molecule or even CO2. Biodegradation has wide applicability to.
