The study looked at how acid rain affects heavy metals in red soils. They used lab experiments to see how different components of acid rain, like sulfate and calcium, impact the release of metals like cadmium and zinc from the soil. They found that higher levels of sulfate and nitrate in acid rain increased the release of cadmium and zinc, while calcium and ammonium decreased their release. The type of metal affected varied depending on the specific component of acid rain. Overall, acid rain can make heavy metals more active in the soil, which could have environmental implications.