干旱区生态环境知识资源中心

The processes of wind erosion of fertile soil, dune movement in sand deserts, dust storms in arid and semi-arid regions, as well as the emission and dispersion of agricultural or industrial dusts create a lot of problems and dangers for human life, environment, and infrastructure. Conventional ways to suppress dust emission to the atmosphere are agricultural fixation in the case of fertile soil surface and application of chemical agents to immobilize dust particulates onto the surface of soil, desert sand, country roads, or mining areas. However, these methods are often too expensive to be applied for large-scale suppression of sand dust. Chemical methods of dust suppression are often environmentally unfriendly due to the release of toxic reagents in water, air, and soil. This paper examines, for the first time, the microbially mediated aggregation of fine sand particles to suppress the emission of sand dust and its chemical and bacteriological pollutants. The bioaggregation reagent was a solution of calcium chloride and urea sprayed over the sand surface, which was preliminarily treated with the suspension of urease-producing bacteria. Quantity of calcium used for sand dust suppression was 15.6 g of Ca/m(2). After the biotreatment of fine sand, the release of sand dust and its artificial pollutants to the atmosphere decreased in comparison with control by 99.8 % for dust, 92.7 % for phenantherene, 94.4 % for led nitrate, and 99.8 % for bacterial cells of Bacillus megaterium. This immobilization of dust and dust pollutants was due to the bioaggregation of fine sand particles. The sizes of 90 % of the sand dust particles increased from 29 mu m in control to 181 mu m after bioaggregation. Bioaggregation treatment of the soil surface could be a useful method to prevent the dispersion of dust and dust-associated chemical and bacteriological pollutants in water, air, and soil.