Phosphate can help clean up soil contaminated with heavy metals. Different types of anions were added to the soil along with phosphate to see how they affected the immobilization of heavy metals. Results showed that adding chloride helped reduce lead levels in the soil, while increasing cadmium levels. Sulfate and fluoride did not have a significant impact on heavy metal levels. Overall, chloride was found to be effective in immobilizing lead with phosphate, and increasing the availability of cadmium in the soil.