Distribution and Remediation Techniques of Heavy Metals in Soil Aggregates Perspective: A Review

Soil aggregates, formed by soil particles and organic matter, have significant impacts on the physical properties of soil and play a crucial role in the migration of nutrients and pollutants. Heavy metals, as harmful soil pollutants, pose important risks to human health and ecosystems. Therefore, understanding the distribution, forms, and migration characteristics of heavy metals in soil aggregates is crucial. This study aims to investigate heavy metal pollution from the perspective of microscopic soil aggregates. A bibliometric analysis was conducted to review studies on the distribution and remediation of heavy metals in soil aggregates over the past 30 years. Based on keyword analysis, the review focused on three main themes: different soil types, adsorption mechanisms and influencing factors of heavy metals on aggregates of different particle sizes, and biochemical remediation. Generally speaking, microaggregates have a strong enrichment capacity for most heavy metals due to their large surface area and numerous adsorption sites. However, the adsorption of aggregates on heavy metals is also related to the physicochemical properties of the soil. Currently, there is relatively little research on the impact of various soil heavy metal remediation techniques on soil aggregates. In the future, this can be strengthened through advanced analytical techniques and modeling methods. Understanding the interaction between heavy metals and soil aggregates is essential for comprehending migration and transformation mechanisms and developing effective remediation technologies. Remediation of heavy metal-contaminated soils using soil aggregates can enhance adsorption and immobilization of heavy metals and improve soil structure. Additionally, the restoration of soil aggregates is vital for soil remediation, enhancing stability, reducing erosion, and promoting the overall recovery of soil ecosystems. Thus, studying heavy metals in soil aggregates is of practical significance for sustainable agriculture and ecological protection.