The study looked at how adding phosphate affects the way cadmium is trapped in soil, depending on how much cadmium is already present. They added different amounts of phosphate to soil with low, medium, and high levels of cadmium, and found that the soil's pH decreased as more phosphate was added. This caused the soil to hold onto less cadmium, especially in soils with lower levels of cadmium. In soils with high cadmium levels, the cadmium formed solid minerals, making it less likely to dissolve. So, adding phosphate can help trap cadmium in soil, especially when there isn't much cadmium to begin with.