Manganese concentrations

Airborne manganese concentrations in the United States range from 0.02 to 0.57 in urban areas and 0.0017-0.047 in nonurban areas. 

A detailed review of the methods for deterrnination of low manganese concentration in water and waste is available (179). A review on the speciation of Mn in fresh waters has been reported (180). Reviews for the chemical analysis of Mn in seawater, soil and plants, and air are presented in References 181, 182, and 183, respectively. 

Human and animal studies indicate that inorganic manganese compounds have a very low acute toxicity by any route of exposure. The toxicity values for a given Mn compound are shown in Table 20 to depend on the species of test animal as well as the route of exposure. Manganese concentrations as high as 2000 ppm were found to be tolerated by test animals over a six-month period without any ill effects (208). 

Manganese. The adult human body contains ca 10—20 mg of manganese (124,125), widely distributed throughout the body. The largest Mg " concentration is in the mitochondria of the soft tissues, especially in the Hver, pancreas, and kidneys (124,126). Manganese concentration in bone varies widely with dietary intake (126) (see Table 10). 

The carbohydrate (again often molasses, 15 - 25%) and added nutrients are pH-adjusted to below 4.0 and, for Otis process, have to be sterilised. It is necessary to add potassium hexacyanoferrate but greater care is required in this process compared to surface culture. The A. niger seems to be more sensitive to and more easily inhibited by hexacyanoferrate in submerged culture. It is essential however to lower the ferrous and manganese concentrations, probably below 200 and 5 pg l1 respectively, to optimise the performance of A. niger. 

Vertisols formed from amphibolite in the Central African Republic contain 300-1000 mg/kg Cr, 11-200 mg/kg Cu, trace amounts to 6 mg/kg Mo and 60-300 mg/kg Ni (Aubert and Pinta, 1977). In chernozem soils of the flood plains of the Amur region, the average Cr is 400 mg/kg. High Co concentrations (100-300 mg/kg) have been found in soils. Manganese concentrations in lithomorphic vertisols are in the range of 3000-5000 mg/kg. Soils on clayey sediments, solonetses and saline alkali soils contain 50-75, 40-100 and 10-50 mg/kg Ni, respectively. 

Klinkhammer [432] has described a method for determining manganese in a seawater matrix at concentrations ranging from about 30 to 5500 ng/1. The samples are extracted with 4 nmol/1 8-hydroxyquinoline in chloroform, and the manganese in the organic phase is then back-extracted into 3 M nitric acid. The manganese concentrations are determined by graphite furnace atomic absorption spectrophotometry. The blank of the method is about 3.0 ng/1, and the precision from duplicate analyses is 9% (1 SD). 

Lambert et al. (1985) reported on a sharp absorption line at 2272 cm-1, which was observed in all the Mn doped InP samples that they studied but whose intensity was not correlated with the manganese concentration in... 

Zinc ligands are soluble in neutral and acidic solutions, so that zinc is readily transported in most natural waters (USEPA 1980, 1987), but zinc oxide, the compound most commonly used in industry, has a low solubility in most solvents (Elinder 1986). Zinc mobility in aquatic ecosystems is a function of the composition of suspended and bed sediments, dissolved and particulate iron and manganese concentrations, pH, salinity, concentrations of complexing ligands, and the concentration of zinc (USEPA 1980). In freshwater, zinc is most soluble at low pH and low alkalinity 10 mg Zn/L of solution at pH 6 that declines to 6.5 at pH 7, 0.65 at pH 8, and 0.01 mg/L at pH 9 (Spear 1981). Dissolved zinc rarely exceeds 40 pg/L in Canadian rivers and lakes higher concentrations are usually associated with zinc-enriched ore deposits and anthropogenic activities. Marine... 

Reactions between Fe(ll) in contaminated groundwater (5.8 mg/L) and oxic sediment also affected As mobility. Ferrous iron was oxidized by manganese oxides to ferric iron which precipitated as hydrous ferric oxide, creating additional sorption sites. Evidence for this reaction included an increase in ferric oxide concentrations in reacted column sediments and manganese concentrations in leachate that were greater than in the initial eluent. 

Sunda, W. G. and Huntsman, S. A. (1986). Relationships among growth rate, cellular manganese concentrations and manganese transport kinetics in estuarine and oceanic species of the diatom Thalassiosira, J. Phycol., 22, 259-270. 

Water conditions, such as temperature, alkalinity, iron levels, and manganese concentrations are all factors that can potentially affect the generation of mixed oxidants and the overall performance of the disinfection process. Some adjustment of the concentration of the mixed oxidant solution may be necessary to prevent scaling in hard-water areas. 

Fig. 20. Catalytic activity of low ignition manganese oxides on alumina as a function of manganese concentration [J. Mooi and P. W. Selwood, J. Avi. Chem. Soc. H, 1750 (1952)].

Table 28-1 Manganese concentration of serum stored in washed and unwashed polyethylene containers...

Since the discovery of widespread hydrothermal activity on the seafloor and plumes of altered water in the water column, it has become obvious that circulation of seawater through both high-temperature and low-temperature rocks can add or remove elements, potentially affecting global balances of some elements. For example, dissolved manganese concentrations in open-ocean seawater are as low as 0.2 nanomole per kilogram, but concentrations... 

Airhom manganese concentrations in Ihe U.S. range from 1)02 to (1.57 lig/im in urban areas and 000)7-0.1)47 ig/m in nim-urban areas. The ACGIH (American Conference of Governmental industrial Hygienists http //www.aegih.org/) recommends a TLV I threshold limit v allies I of... 

Figure 9. Left digital photograph ofa selected area ofsample WJJ122, followed by elemented contour maps of iron, copper, and manganese concentrations on the surface of the sherd. Darker areas on the contour maps indicate higher elemental concentrations for that element. The analyzed area is 10 x 18 mm. Sampling was conducted at 1 mm intervals.

For instance, the manganese determination by molecular absorption spectro(photo)metry can be made using different types of instruments which have various technical performances. Some results are shown (Fig. 4) for manganese concentration measurements with a DR 2000-wide bandwidth 8 nm (series 1) a Hewlett Packard 8452 A, bandwidth 2 nm (series 2) and a Spe-cord M 40-narrow bandwidth 1 nm (series 3). 

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