Arsenic speciation, mechanisms, and factors affecting rice uptake and potential human health risk: A systematic review

Abstract

Arsenic (As), being the first class of carcinogen, reflects disastrous threats to living beings owing to its high persistence, toxicity, bioaccumulation, and bioavailability in the environment. The toxicity of As notably linked with its inorganic forms such as arsenite (AsIII) and arsenate (AsV). The As-contaminated water irrigation of rice field led to its accumulation in topsoil and bioavailability to rice crops. Among As species, the AsIII is predominant species in the topsoil of paddy fields and growing rice grain. Rice grain ranked as the second extensive global cultivated cereal crop and used as a staple food by billions of people around the world. This study presents an overview regarding the conditions, factors, and mechanisms in the soils that affect the As oxidation, reduction and methylation in soils and uptake in rice plants. This paper not only considers the As uptake in the grains of rice varieties but also focused on its biotransformation to the diet of human and cancer risk. The uptake of As by rice crops showed a major exposure pathway in the people having high rice consumption. The relevant updated findings of As and its speciation in rice, mechanisms, and controlling factors are critically discussed, while the gaps in the existing literature and directions for future research work are identified in this study which may be helpful for global scientific communities.