Cadmium (Cd) distribution and contamination in Chinese paddy soils on national scale

Abstract

Rice is a staple food by an increasing number of people in China. As more issues have arisen in China due to rice contaminated by cadmium (Cd), Cd contamination in arable soils has become a severe problem. In China, many studies have examined Cd contamination in arable soils on a national scale, but little studies have focused on the distribution of Cd in paddy fields. This study explored the spatial pattern of Cd in paddy soils in China, made a preliminary evaluation of the potential risk, and identified the most critically contaminated regions based on the domestic rough rice trade flow. The results showed that Cd concentrations in paddy soils in China ranged from 0.01 to 5.50 mg/kg, with a median value of 0.23 mg/kg. On average, the highest Cd concentrations were in Hunan (0.73 mg/kg), Guangxi (0.70 mg/kg), and Sichuan (0.46 mg/ kg) provinces. Cd concentrations in paddy soils in central and western regions were higher than those in eastern regions, especially the southeastern coastal regions. Of the administrative regions, Cd standard exceedance rate was 33.2 %, and the heavy pollution rate was 8.6 %. Regarding to Cd of paddy soil, soil environmental quality was better in Northeast China Plain than in Yangtze River Basin and southeastern coastal region. Mining activities were the main anthropogenic pollution source of Cd in Chinese paddy soil. Based on rice trade, more of the Chinese population would be exposed to Cd through intake of rice produced in Hunan province. Certain regions that output rice, especially Hunan province, should be given priority in the management and control of Cd contamination in paddy soil.

Combined Effect of Ferrous Ion and Biochar on Cadmium and Arsenic Accumulation in Rice

“…Anthropogenic activities and mining are major sources of metals accumulation in soils, especially in agricultural soils [1,2]. The pollution of Cd in paddy soils is a widespread problem due to its potential harm to plants and human health [3].…”

“…The pollution of Cd in paddy soils is a widespread problem due to its potential harm to plants and human health [3]. Rice (Oryza sativa L.) is a widely cultivated crop in China [1], and also a common dietary source for Cd and As exposure. A number of studies have reported that metal contents exceed safe values [4].…”

An operon consisting of a P-type ATPase gene and a transcriptional regulator gene responsible for cadmium resistances in Bacillus vietamensis 151–6 and Bacillus marisflavi 151–25

“…Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China. 2 College of Life Science and Technology, Jinan University, Guangzhou, Guangdong, China.…”

“…Soil contamination with heavy metals is becoming an increasingly urgent problem worldwide. Among all heavy metals, one of the most hazardous is cadmium (Cd) [1,2]. Cd is a non-essential heavy metal element that is toxic, teratogenic and carcinogenic to humans.…”

Effects of Biochar on Cadmium Accumulation in Rice and Cadmium Fractions of Soil: A Three-Year Pot Experiment

“…Rice is a staple food for nearly 60% of China's population and has very important planting status in China. However, in recent years, it is not uncommon to find the reports that the cadmium content of rice has exceeded the standard due to soil pollution (Liu et al 2016a). This study is from the perspective of practical production and application.…”