As per the earlier research by , soil enzyme activity did not significantly change at a Cd concentration of 10 μg/g. However, an increase to 50 μg/g led to a decrease in enzyme activity, which was more noticeable in sandy loam soils as opposed to loam or clay loam soils. Additionally, reported that urease activity completely vanished in 2000 μg/g of heavy metals including Zn 2+ and Cu 2+ .