Supported by the National Key Research and Development Program of China (No. 2018YFD0800300), the Major R & D Projects of Jiangxi Province, China (No. 20194ABC28010) and the Key Project in Scientific and Technological Development of Henan Province, China (No. 232102320094)
Cadmium (Cd) pollution is dispersed over a wide area in farmland soils and seriously threatens the safety of agricultural produce and sustainable development of agriculture due to rapid industrialization and inadequate environmental protection in China. Compared to other toxic elements, Cd is highly carcinogenic and readily accumulates in edible portions of plants to levels that are toxic to humans. Traditional technologies of chemical remediation, physical remediation and phytoremediation have been widely applied to remediate Cd-polluted arable soil, especially in acid soil in some areas of southern China. However, little is known about the remediation technologies of Cd for alkaline arable soils. Alkaline soils are mainly distributed in North China. This area is an important hub for both the crop growing and animal breeding industries, and is suffering from severe Cd pollution as well. To ensure food safety, it is necessary to establish the technology and theory of Cd purification in alkaline soils. This paper reviews the domestic and foreign research trends of Cd remediation strategies, hot technologies, Cd geochemical cycle, and Cd transport and accumulation mechanisms in wheat grains, and analyzes the scientific and technological issues of Cd management and control in alkaline soils. The Web of Science core collection database (WOS) were employed to conduct a bibliometric analysis of the literature on remediation technologies of Cd in alkaline arable soils from 2000-2021 via VOSviewer software. The immobilization technology is popular to remediate Cd contamination in alkaline soils and the top three countries in the number of publications are China, the United States and Australia because of their abundant agricultural resources. Besides, soil acidification is the main reason for the increasing grain concentrations of Cd in alkaline arable soils. Meanwhile, lower soil Eh can increase Cd bioavailability by flooding in alkaline soils, suggesting that irrigation and drainage projects should be built in dry-land soil in North China. However, compared with acidic soil, the research on Cd remediation technology in alkaline arable soils is relatively weak. Currently, alkaline amendments such as clay minerals, biochar and lime are usually applied to lower Cd bioavailability in alkaline soils. However, it is difficult to inhibit the accumulation of Cd in crop grains by improving soil pH due to the large amount of carbonate in alkaline soils. Moreover, the excessive addition of alkaline amendments can destroy the soil structure, leading to soil hardening. Also, in phytoremediation, the high pH of alkaline soil will reduce the uptake of Cd by plant roots, resulting in low remediation efficiency and high cost. The accumulation of Cd in wheat grains is affected by both biotic and abiotic factors, and the complex molecular mechanism of its uptake and transport also limits the development of low-accumulation varieties. Thus, local governments should monitor the Cd concentration and it is imperative to explore and develop new technologies for inhibiting the transfer of Cd to food crops in alkaline soils.
张力浩,白姣杰,田瑞云,王国昌,游来勇,梁家妮,慈凯东,刘梦丽,寇乐勇,周伶俐,周俊,吴大付,孙斌,周静.中国北方碱性农田土壤镉污染修复：现状与挑战[J].土壤学报,2024,61(2):348-360. DOI:10.11766/trxb202209110503 ZHANG Lihao, BAI Jiaojie, TIAN Ruiyun, WANG Guochang, YOU Laiyong, LIANG Jiani, CI Kaidong, LIU Mengli, KOU Leyong, ZHOU Lingli, ZHOU Jun, WU Dafu, SUN Bin, ZHOU Jing. Cadmium Remediation Strategies in Alkaline Arable Soils in Northern China: Current Status and Challenges[J]. Acta Pedologica Sinica,2024,61(2):348-360.复制