Abstract
Heavy metals from hazardous waste, such as batteries, electronics, cleaning products, and cosmetics, can be transported to soil through landfill leachates. Due to their persistent structure, these toxic metals such as Cr, Co, Pb, and Cd accumulate in the soil and can cause various ecological and health risks. Hence, this study aims to assess the extent of heavy metal pollution in Iranian landfills soil. The present study has reviewed previous research on the assessment of heavy metal contamination such as lead, arsenic, chromium, cadmium, zinc, cobalt, and nickel in soils of landfill sites. For this purpose, articles related to the topic were examined from all accessible electronic databases for academic literature such as "Magiran", "SID", "IranMedex", "Scopus", "PubMed", "ScienceDirect" and "Web of Science" until 2024. The search used Persian and English keywords for heavy metals, waste disposal sites, soil, and Iran. Eventually, out of 206 articles, 21 studies met our inclusion criteria and were included in the study. The results indicated that heavy metals concentration, including Pb, As, Cr, Cd, Zn, Co, and Ni were found to be higher than Iranian and international standards in some soil samples. Therefore, landfill sites, as an anthropogenic resource, have the potential to transmit pollution to the soil. Contamination levels depend on waste composition, hazardous content, leachate production and migration, landfill age and design, soil characteristics, and operating conditions. Health and ecological risks can be mitigated by reducing hazardous waste, recycling heavy metal-containing wastes, installing anti-seepage systems, and maintaining continuous monitoring.