The ethnographer says the removal of the top soil is an effort to decontaminate the place. At the same time, the machines used damage the underground pipes. I would be curious to know more about how the latter contributes to a different form of toxicity perhaps that comes with flooding and draining of the fields?
This is an image taken by the ethnographer and zooms into the 1m measurement of the soil. It doesn't show the layers in the soil to the readers but this is explained in the caption.
The visualization and caption shows an example of how de-contamination happens and its effects on a micro-scale through a literal shifting of the terrain (shifting of the soil). I read this as an attempt by the ethnographer to show how the meaning of toxicity is complex, and the role of the nonhuman (Terrain, soil, plants, clay) in shaping how toxicity is knowable to humans.