Cadmium dissertation in natural speciation water
Cadmium In Natural Speciation Thesis Water - Thesis …
There is little evidence for manganese–organic associations in natural waters, with manganese only weakly bound to dissolved organic carbon (L'Her Roux et al., 1998). Hence, organic complexation does not play a major role in controlling manganese speciation in natural waters. Field studies have confirmed that organically bound manganese is minor, even with high natural dissolved organic carbon levels (Laxen et al., 1984). The Mn(II) ion is more soluble than Mn(IV); therefore, manganese will tend to become more bioavailable with decreasing pH and redox potential (Heal, 2001). The presence of chlorides, nitrates, and sulfates can increase manganese solubility and thus increase aqueous mobility and uptake by plants (Reimer, 1999). Hart et al. (1992) studied the speciation of manganese in Magela Creek in tropical north Australia. They hypothesized that higher temperatures (30 °C) and increased rates of bacterially mediated oxidation could result in equilibrium between Mn(II) and oxidized species within the normal residence time of water in the creek. This was one mechanism by which colloidal manganese could dominate speciation.
The chemistry of cadmium in natural water
Some cadmium salts, such as the sulfide, carbonate, and oxide, are practically insoluble in water; these can be converted to water-soluble salts in nature.