Cadmium contamination of soil and crops is affected by intercropping and rotation systems in the lower reaches of the Minjiang River in south-western China.

Yang Liu,Shun Gao,Fuzhong Wu,Li Zhang,Peng Zhu,Lianghua Chen,Wanqin Yang,Kai Liu,Yong Li,Jian Zhang

doi:10.1007/s10653-015-9762-4

Abstract

Cadmium (Cd) accumulation and pollution in arable soils are particularly serious in the lower reaches of the Minjiang River in southwest of China. In this study, the remediation efficiency of Cd contamination in arable soils, the distribution pattern of Cd concentration in crops, and the food safety to humans of three typical cropping systems (S1: maize + sweet potato—Chinese cabbage, S2: maize + ginger—stem mustard, and S3: rice) were investigated and evaluated. After 1-year rotation, the percentage of Cd extracted by crops from the plough soil layer was observed in three system fields with the trend of S1 (2.30 %) > S2 (1.16 %) > S3 (0.21 %) and Cd extraction amount in crops was maximum in sweet potato, then in maize. The same kind of crop had the same pattern of Cd distribution in organs, and the edible parts generally accumulated less Cd amount than the inedible parts. Further, the grain crops were found to possibly be suitable one for using as phytoaccumulators of Cd contamination for farmlands. Direct consumption of these crops from the three systems would pose a high health risk to local inhabitants since it would result in the monthly intake of Cd (247 μg kg−1 body weight) being nearly 10 times higher than the recommended tolerable monthly intake (RTMI) (25 μg kg−1 body weight), resulting mainly from the consumption of vegetables rather than the grains, which would be potentially reduced by these foods being consumed by livestock firstly.

Highlights

These studies typically focused on just the food safety, as determined by the low level of metal accumulation in the edible parts of plant, while ignoring the ability of remediation of the heavy metals from soil
Cd is generally present in the environment at low level; human activities have greatly increased the level in this study area
According to the MPLsoil of Cd for agricultural soil set by the Chinese government (Table 3) (NEPA and ATS 1995), single pollution index (SPI) of Cd in soils of three systems reached the values of 5.80, 6.22, and 18.07, respectively

Summary

Introduction

Cd accumulates to different levels in different species and different cultivars within species that are called CSCs (Cd-safe cultivars) (Grant et al 1998; Yu et al 2006; Liu et al 2010), as well as different distribution patterns of Cd among species in many studies (Choudhary et al 1994; Yang et al 1995; Grant et al 1998) These studies typically focused on just the food safety, as determined by the low level of metal accumulation in the edible parts of plant, while ignoring the ability of remediation of the heavy metals from soil. In this area, various typical intercropping and rotation systems with different crops have long been used. Field experiments using three typical intercropping and rotation systems in this area were conducted to: (1) investigate the different abilities of different cultivated systems for Cd removal from soil, (2) quantify the different concentrations and distribution patterns of Cd in different crops, and (3) assess the food safety by calculating the daily intake levels of Cd when consuming these crops

Methods

Results

Conclusion