Sources, dynamics, and mitigation strategies of arsenic and cadmium and their co-contamination in paddy systems: A comprehensive review

Arsenic (As) and cadmium (Cd) are two of the most prevalent toxic trace elements in paddy fields, especially in East and South Asia. These elements pose significant environmental and health risks due to their potential for bioaccumulation in rice, a staple food for half of the world's population. Despite extensive research, their contrasting chemical properties under different environmental conditions have made simultaneous mitigation challenging. This chapter aims to review the input and transformation processes of As and Cd in paddy soils and the key influencing factors determining these processes. It will also discuss relevant mitigation strategies based on current knowledge. This work systematically explores the common and distinct sources of As and Cd contamination in paddy soils, focusing on natural and anthropogenic inputs such as mining, industrial activities, fossil fuel combustion, and chemical and manure fertilizers. The environmental behaviors of As and Cd, including their redox transformations and interactions with soil components, are analyzed in detail to assess their mobility and bioavailability in typical paddy environments. Key factors influencing the fate of As and Cd in paddy soils, such as redox potential, pH, and competing ions, are highlighted. Furthermore, various mitigation strategies based on these theories, including water management, soil amendments, and crop breeding, are discussed to address the complex challenge of As and Cd co-contamination. Finally, we highlight the current limitations in the widespread implementation of remediation technologies and propose future research directions. This chapter provides a comprehensive understanding of the environmental dynamics of As and Cd in paddy fields and offers insights into potential solutions for ensuring safe rice production and public health. Copyright © 2026 Taylor & Francis Group, LLC.