The Status and Research Progress of Cadmium Pollution in Rice- (Oryza sativa L.) and Wheat- (Triticum aestivum L.) Cropping Systems in China: A Critical Review

Abstract

The accumulation of cadmium in rice (Oryza sativa L.) and wheat (Triticum aestivum L.) is a serious threat to the safe use of farmland and to the health of the human diet that has attracted extensive attention from researchers. In this review, a bibliometric analysis was performed using a VOS viewer (1.6.18, Netherlands) to investigate the status of cadmium contamination in rice and wheat growing systems, human health risks, mechanisms of Cd uptake and transport, and the corresponding research hotspots. It has a certain reference value for the prevention and control of cadmium pollution in rice and wheat planting systems in China and abroad. The results showed that the Cd content in rice and wheat planting systems in the Yangtze River Basin was significantly higher than that in other areas of China, and the Cd content in rice and wheat grains and the hazard quotient (HQ) in Hunan Province was the highest. The average Cd concentration exceeded the recommended limit by about 62% for rice and 81% for wheat. The main reasons for the high Cd pollution in rice and wheat growing areas in Hunan are mining activities, phosphate fertilizer application, sewage irrigation, and electronic equipment manufacturing. In this review, we demonstrate that cadmium toxicity reduces the uptake and transport of essential elements in rice and wheat. Cadmium stress seriously affected the growth and morphology of plant roots. In the shoots, Cd toxicity was manifested by a series of physiological injuries, such as decreased photosynthesis, soluble protein, sugar, and antioxidant enzyme activity. Cadmium that accumulates in the shoots is transferred to grains and then passes up the food chain to people and animals. Therefore, methods for reducing cadmium content in grains of rice and wheat are urgently needed, especially in Cd-contaminated soil. Current research on Cd pollution in rice and wheat planting systems focuses on the bioavailability of Cd, soil rhizosphere changes in wheat and rice, and the role of antioxidant enzyme systems in alleviating heavy metal stress in rice and wheat.

Assessment of Heavy Metal Content and Consumption Risks At Selected Paddy Field in Malaysia: A Review

“…It is also evident that, based on in-depth analyses of numerous fertilizer products, some micronutrient and phosphate fertilizers contain elevated Cd compared to others. The public's main concern is the persistent nature of Cd and its bioaccumulation in the food chain (Gao et al 2022). The effect of Cd on the human body is kidney disease and can potentially affect the pulmonary, cardiovascular, and musculoskeletal systems (Munir et al 2023).…”

Significant Synergy Effects of Biochar Combined with Topdressing Silicon on Cd Reduction and Yield Increase of Rice in Cd-Contaminated Paddy Soil

“…Rice is one of the most important cereal crops in China and is also the staple food for more than 60% of the world's population. It is important to ensure Agronomy 2024, 14, 568 2 of 15 the safe production of rice for food security in China [4]. Long-term consumption of Cdcontaminated rice would cause excessive Cd accumulation in the human body, leading to kidney dysfunction, threatening the nervous system and triggering diseases such as osteoporosis and cancer [5][6][7].…”

Monitoring and assessment of heavy metal transfer from soil to Beta vulgaris L. (sugar beet) in Kayseri, Turkey

“…Heavy metals also negatively affect the uptake of nutrients in the soil. In this case, insufficient intake of the elements leads to shortening of the root body and length of the plant, decrease in the number of leaves, reduction of the leaf surface area and many other negative effects (Alfaro et al, 2022;Gao et al, 2022;Zhang et al, 2022). In excess, it causes burns on the leaves, stunting of the roots and stems, and negativities in amino acid binding and protein synthesis.…”