Top topic this week
Back to FAQs
Related FAQs
Frequently Asked Question
Questions asked by users might not always be phrased in the clearest way.
Why is liming used to treat some soils with higher heavy metal content?
Accepted Answer
Liming, the application of calcium carbonate (CaCO3) or other alkaline materials to soil, can help reduce the bioavailability of certain heavy metals by increasing the soil pH. Here's how it works:
Increased pH: Liming raises the soil pH, making it less acidic. Heavy metals like lead, cadmium, and mercury are more soluble in acidic soils, meaning they are more readily available to plants and can potentially enter the food chain. By increasing pH, liming reduces the solubility of these metals, effectively locking them up in the soil.
Precipitation: Some heavy metals form insoluble precipitates at higher pH levels. As the soil pH rises, the metals are less likely to remain in a dissolved form and instead bind with other compounds to form solid, less harmful substances.
Increased cation exchange capacity: Liming can increase the soil's ability to hold onto essential nutrients, making them less likely to be replaced by heavy metals.
However, it's important to note that liming is not a universal solution for all heavy metal contamination. Its effectiveness depends on the specific metals present, the soil type, and other factors. Additionally, excessive liming can also have negative impacts on soil fertility.
Articles you might like