Читать книгу Environmental and Agricultural Microbiology - Группа авторов - Страница 50

Arsenic present in periodic table of period 4 and group VA in metalloid state. The inorganic form includes trivalent arsenite (AsIII) and pentavalent arsenate (AsV) and methylated metabolites are organic form of arsenic, e.g., monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and trimethylarsine (TMA) oxide. Atmospheric pollutions occur through arsenic due to volcanic eruption, soil erosion, and anthropogenic activities [24]. In ores, arsenic generally exists in powdery amorphous and crystalline forms. It enters in to the environment through withstand of rocks, mining and smelting methods, pesticide practice in agriculture, and coal ignition. It causes ground water as well as surface water contamination and exists as arsenate (AsV) and arsenite (AsIII) in maximum groundwater. Its high concentrations in drinking water create toxic effect to animal and human [22].

Industrial product in agricultural application such as herbicides, insecticides, sheep dip, dye-stuffs, preservatives of wood and algicides contains arsenic compounds or components. Arsenic is also used in veterinary medicines and medical treatments in drugs to treat syphilis, yaws, amoebic dysentery, and Trypanosomiasis like diseases [25, 26]. Arsenic compound also create genotoxicity by inhibiting DNA repair, promote chromosomal aberration, exchanges of sister chromatid, and micronuclei development in both rodent and human cells [27, 28].