Manganese [Mn, 25]
193
varies from 400 to 1000 kt/yr. The majority of Mn is in suspended particulate matter,
which is concentrated at deeper water layers, from 30 to over 200 m (Brügmann vide
Kabata-Pendias and Mukherjee 2007). Suspended matters in the Baltic Sea contain variable amounts of Mn, from 20 to 73,000 mg/kg (Szefer 2002). Atmospheric input of Mn
with rainwater to the oceans is an important source of its stable and soluble species in
surface seawater (Willey et al. 2009). Rainwater is thought to be a main removal mechanism for the atmospheric Mn. The reductive dissolution of Mn oxides, due to microbial
reductions, controls Mn mobility and its transfer to well water (Petrunic et al. 2005).
All compounds and species of Mn in water are easily transferred into colloidal
forms, and precipitated in bottom sediments. These processes are highly controlled
by variations in the redox conditions of water and sediments. Formation of Mn–Fe
nodules has an impact on the behavior of some other metals.
Manganese content of some sediments may be very high. Mn content in rivers of
some EU countries is 770 mg/kg (Odra River) and 960 mg/kg (Rhine River), respectively. Sediments of the Baltic Sea contain Mn within the range of 120–2290 mg/kg,
and sediments of some gulfs may have up to 7260 mg/kg (Szefer 2002).
Manganese contents in stream-bottom sediments of National Park, Montgomery
(Pennsylvania State) were, in 1995, within the range of 430–34,000 mg/kg (Reif
and Sloto 1997). Sediments of Sergipe River estuary (Brazil) contain Mn from 7.2
to 251 mg/kg (Garcia et al. 2011). Mn concentration in the wetland sediments from
the effluent at the Savannah River site (Aiken, SC) is 458.5 mg/kg, and its highest
amounts, 365.3 mg/kg, are fixed in SOM fraction (Knox et al. 2006).
Median Mn concentration in bottled water of the EU countries is 0.81 μg/L, and
is higher than those in tap water, 0.54 μg/L (Birke et al. 2010). Guideline for Mn in
drinking water is not established, as it is not of health concern (WHO 2011a).
Due to reactions of Mn with some metals, especially with Cd and Pb, its presence
in water may decrease metal toxicity to some water biota. However, these processes
may lead to Fe deficiency in some algae.
Manganese is likely to concentrate in shells of mollusks, in the form of layers
at the surface of the shell. Its contents in shells of some mollusks from the Baltic
Sea is within the range of 7.5–233 mg/kg, and in some species (cockle) may be over
34,000 mg/kg (Szefer 2002).
26.4 AIR
The origin of Mn in the atmosphere is from both terrestrial and anthropogenic sources.
Its concentrations in air vary from <0.02 ng/m 3 above Antarctica up to 900 ng/m 3 in
industrial regions (Table 26.1). Median world Mn content in air has been estimated at
2 ng/m 3 (Reimann and de Caritat 1998). In air of some cities, not industrialized, Mn
amounts average at about 10 ng/m 3 (Bankovitch vide Kabata-Pendias and Mukherjee
2007). One of the principal sources of inorganic Mn, as a pollutant in the urban atmosphere, is the combustion of MMT, particularly in areas of high traffic density. MMT
was used as a gasoline additive in several countries, since 1990s.
The total worldwide emissions of Mn in 1983 ranged from 10.56 to 65.97  kt,
with the predominant sources from coal combustion, and secondary, from nonferrous metal production, and sewage sludge incineration (Nriagu and Pacyna 1988).