Cry1Ab Adsorption and Transport in Humic Acid-Coated Geological Formation of Alumino-Silica Clays
2017
Yuan, Hongying | Li, Simeng | Liu, Junliang | Song, Chengyi | Chen, Gang
Genetically modified agricultural products have been introduced to increase food supply by enhancing their resistance to pests and diseases, along with easily adapting to environmental conditions. Due to the modification of DNA, public objections are prevalent, including concerns on the impact on the ecosystem. In this research, adsorption and transport of Cry1Ab, a toxin exuded by the transgenic Bt maize in alumino-silica clays, were evaluated in laboratory columns under steady-state flow conditions. Since Cry1Ab fate and transport were very responsive to animal waste field applications, during which humic acids were released, Cry1Ab adsorption and transport in humic acid-coated alumino-silica clays were also investigated. Cry1Ab breakthrough curves were simulated using the convection-dispersion transport models. It was discovered that the humic acid coating increased Cry1Ab deposition during the transport. Based on analysis of the breakthrough curves, adsorption isotherms of Cry1Ab in alumino-silica clays were obtained and compared with those of batch experiments. The humic acid coating changed the bonding energy between Cry1Ab and the adsorption receptor sites on alumino-silica clay surfaces, thereby changing Cry1Ab partition between the aqueous phase and the solid phase.
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