Safety of African grown rice: Comparative review of As, Cd, and Pb contamination in African rice and paddy fields

Angstone Thembachako Mlangeni; Evans Chinthenga; Noel Jabesi Kapito; Sydney Namaumbo; Joerg Feldmann; Andrea Raab

doi:10.1016/j.heliyon.2023.e18314

Safety of African grown rice: Comparative review of As, Cd, and Pb contamination in African rice and paddy fields

Heliyon. 2023 Jul 15;9(7):e18314. doi: 10.1016/j.heliyon.2023.e18314. eCollection 2023 Jul.

Authors

Angstone Thembachako Mlangeni¹, Evans Chinthenga¹, Noel Jabesi Kapito¹, Sydney Namaumbo¹, Joerg Feldmann², Andrea Raab²

Affiliations

¹ Department of Land and Water Resources, Natural Resources College, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi.
² TESLA Analytical Chemistry, Institute of Chemistry, University of Graz, Austria.

Abstract

This review aimed to investigate the reported concentrations of arsenic (As), cadmium (Cd), and lead (Pb) in rice cultivated in Africa and African rice paddies compared to other regions. It also aimed to explore the factors influencing these concentrations and evaluate the associated health risks of elevated As, Cd, and Pb exposure. Relevant data were obtained from electronic databases such as PubMed, Scopus, and Google Scholar using specific keywords related to arsenic, cadmium, lead, rice, Africa, paddy, and grain. While the number of studies reporting the concentrations of As, Cd, and Pb in rice and rice paddies in Africa is relatively low compared to other regions, this review revealed that most of the African rice and paddy soils have low concentrations of these metals. However, some studies have reported elevated concentrations of As, Cd, and Pb in paddy fields, which is concerning due to the increased use of agrochemicals containing heavy metals in rice production. Nonetheless, agronomical interventions such as implementing alternate wetting and drying water management, cultivating cultivars with low accumulation of As, Cd, and Pb, amending rice fields with sorbents, and screening irrigation water can limit the bioaccumulation of these carcinogens in paddy fields using phytoremediation techniques. Therefore, we strongly urge African governments and organizations operating in Africa to enhance the capacity of rice farmers and extension officers in adopting approaches and practices that reduce the accumulation of these carcinogenic metals in rice. This is essential to achieve the sustainable development goal of providing safe food for all.

Keywords: Arsenic (As); Bioavailability soil sorbents; Cadmium (Cd); Cultivar; Lead (Pb); Rice.

Publication types

Review