Sorption of the toxin of Bacillus thuringiensis subsp. kurstaki by soils: effects of iron and aluminium oxides

Abstract

Transgenic Bacillus thuringiensis (Bt)‐modified plants release Bt toxins into soil and, as a result of worldwide adoption of this technology, concern about their environmental effects has arisen. The sorption of Bt toxin has been studied on four contrasting soils: latosol (Ferralsol), latosolic‐red soil (Ferralsol), red soil (Acrisol) and paddy soil (Anthrosol). Sorption of Bt toxin was also measured on residues of these soils after chemical treatment to remove free (Fed and Ald), amorphous (Feo and Alo) and exchangeable Fe and Al (FeEx and AlEx). The results indicated that the specific surface area (SSA) of soils decreased after the removal of Fe and Al, especially after the removal of Fed and Ald. However, the absence of these three species of Fe and Al did not have a significant effect on the organic matter (OM) content of soil residues when compared with their intact soils. The presence of Fed and Ald, Feo and Alo and FeEx and AlEx increased the sorption of Bt toxin by soil, and the influence of Fed and Ald (with about 46% decrease) was greater than the effect of the other two species of Fe and Al.

A New Indicator to Better Represent the Impact of Landscape Pattern Change on Basin Soil Erosion and Sediment Yield in the Upper Reach of Ganjiang, China

“…Granite is a typical representative of magmatic rocks in the basin. The main soil type is Acrisols, which is an acidic soil that is rich in iron and aluminum oxides and which forms in humid climates [26]. The terrain in this area is dominated by low mountains and hills [27].…”

Soil Interfaces in a Changing World

“…A particular case of protein sorption on soil colloids is that of the Bacillus thuringiensis (Bt) toxin, released in large amounts by Bt ‐modified plants to soil via root exudates. Fu et al (2012) described the sorption of Bt toxin on four contrasting soils, whose surfaces were modified by removing different forms of Fe and Al oxides. These treatments caused an increase in the specific surface area of soils with no significant effect on the organic matter content of soil residues, thus demonstrating that Fe and Al oxides contributed to the sorption of Bt toxin by soil.…”