Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China.

Zhouping Liu,Yanfei Ding,Junwei Sun,Cheng Zhu,Tiqian Han,Qiaofen Zhang,Feijuan Wang

doi:10.3390/ijerph13010063

Zhouping Liu, Yanfei Ding + Show 5 more

Open Access

https://doi.org/10.3390/ijerph13010063

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Abstract

Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg−1, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM). This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety.

Highlights

Heavy metals are regarded as nonessential and toxic trace elements in the environment [1].Due to their potential toxicity, as well as their persistent and irreversible accumulation characteristics, heavy metals, such as Cd, Pb, Hg, and Cr, are listed as key monitoring pollutants by the ChineseMinistry of Environmental Protection [2]
The results show that some soil samples from this region were polluted by Cd and Hg, and heavy metal contamination is serious at some sample sites
Our results showed that the soil was not polluted by Pb and Cr, but the concentrations of Pb and Cr exceeded the threshold values in rice grain; this may be related to sewage water irrigation on the soil surface, heavy metal deposition from the air, fertilizers and the variety of rice being cultivated [25,38,39,40]

Summary

Introduction

Heavy metals are regarded as nonessential and toxic trace elements in the environment [1].Due to their potential toxicity, as well as their persistent and irreversible accumulation characteristics, heavy metals, such as Cd, Pb, Hg, and Cr, are listed as key monitoring pollutants by the ChineseMinistry of Environmental Protection [2]. Heavy metals are regarded as nonessential and toxic trace elements in the environment [1]. Due to their potential toxicity, as well as their persistent and irreversible accumulation characteristics, heavy metals, such as Cd, Pb, Hg, and Cr, are listed as key monitoring pollutants by the Chinese. Cr is classified as a priority pollutant in Category A (human carcinogen), while Cd and Pb are classified in Category B (probable human carcinogen) by the United States Environmental Protection Agency [3]. Heavy metals that accumulate and migrate in soil influence plant growth and yield, and have the potential to accumulate in the human body through the food chain, posing a serious threat to human health [7,8,9]. Paddy rice is one of the main global food sources, and China is the largest

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