Bacteria soil aeration

The Harding ESE, Inc., in situ vadose zone soil treatment uses indigenous bacteria and formulations of mineral nutrients to treat biodegradable chemicals in soil. The technology only treats contaminants in the soil s vadose zone (the zone below the surface but above the water table also known as zone of aeration). 

Stout and Heal summarize the morphological and physiological characters that appear to favor the existence of Protozoa in soil as follows Small size and simple structure a capacity for rapid multiplication under favorable conditions encystment and excystment mechanisms adapted to fluctuations of soil moisture, salinity, aeration and food supply tolerance of a wide range of pH and temperature the ability to absorb nutrients in dissolved or particulate form. The rhizosphere of plants is a favorable environment for Protozoa because of the increased food supply in the forms of bacteria, plant excretions and plant residues. Although soil Protozoa can feed on a wide range of bacteria, they can apparently exercise a choice as to the species that they prefer. 

Concentrations up to 2000 mg/kg were found in soils close to metallurgical foundries. Soils contaminated with pesticides may contain up to 290-625 mg/kg. Aerated soil layers at the surface contain As(V), whereas industrial pollution or agricultural pesticides are composed mainly of As(III). Arsenate ions are fixed by many soil components, especially hydrated Fe and A1 oxides. The transfer of arsenic from soil to plants is low, i.e., 0.1-0.5 mg/m. The kind of plant may have an influence (see Sec. 2.1.4) but there is no more detailed information. Several strains of bacteria in the environment accelerate the oxidation of As(III) to As(V) or methylate and alkylate arsenic mainly to DMAA which is partially released to the atmosphere. High contaminations of As(III) destroy these microorganisms [4,8,12,18-21,26]. 

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