Seasonal Manganese in a Public Water Supply

Manganese in Deep Reservoirs

“…The data in Table I disclose that the carbon dioxide con-centration must be twice that of the oxygen, or there must be a carbon dioxide-oxygen ratio of at least 2 before manganese will be dissolved and retained in solution. This is not surprising, since the previous study (7) disclosed that the solubility of the manganese was in direct ratio to the concentration of carbon dioxide, when the temperature had been higher than 20°C. for at least 60 days.…”

“…Weston (IS) stated that the manganese was dissolved by the action of organic and mineral acids. An investigation by Hopkins and McCall (7) in 1931 indicated that the solution of manganese was caused by anaerobic fermentation of vegetation on the bottom of the unstripped Loch Raven Reservoir, with the liberation of large quantities of carbon dioxide as a by-product which dissolved the manganese from the muck and underlying soil. The biological activity was accelerated at temperatures above 20°C.…”

Manganese in the Loch Raven Reservoir

“…In 1932, E. S. Hopkins and G. B. McCall (9) demonstrated that, as Baylis had predicted, the magnitude of the annual manganese peaks was smaller each year until the years 1929 and 1930, when, due to drought conditions, there was an absence of silting, which prevented the usual covering of the mangahese rock and organic material on the reservoir bottom.…”

Algae and Other Organisms in Waters of the Chesapeake Area

“…The manganese enters the water by being absorbed from the rocks and soil of freshly inundated areas (42). Digestion of organic material at the bottom of reservoirs has been considered the underlying cause, as water containing free carbon dioxide and lacking oxygen tends to dissolve hydrated manganous oxides (43). Studies have been conducted at Baltimore and Luke, Md., to determine the role of bacteria and of plankton in accelerating the process of digestion and in furnishing the organic matter through settling of dead microorganisms to the bottom (44,45).…”