Soil affects on the cadmium and zinc contents of Chinese cabbage in Yunnan Province, China

Abstract

Chinese cabbage and surface soil samples (0–20 cm) from a periurban market garden in Yunnan Province (P.R. China) were collected to determine variations of cadmium (Cd) and zinc (Zn) contents in Chinese cabbage and the influence of soil factors. Mean Cd content was 0.49 mg kg⁻¹ dry materials (DM) in Chinese cabbage, ranging between 0.23 and 1.34 mg kg⁻¹ DM (n = 21 samples). Mean Zn content was 51.2 mg kg⁻¹ DM, ranging from 34.9 to 157.5 mg kg⁻¹ DM (n = 21 samples). The soil factors best predicting Chinese cabbage Cd and Zn contents were total and available Cd and Zn contents and cation exchange capacity (CEC). Soil samples and corresponding Chinese cabbage samples were divided into two groups: soils with low pH (<6.5, n = 10) and soils with high pH (>6.5, n = 11). Positive correlation between CEC with pH > 6.5 and Cd and Zn contents in Chinese cabbage were observed. Available trace element contents and CEC explained 77% and 69% of variation of Cd and Zn contents in Chinese cabbage, respectively. AEC (enrichment coefficient related to trace element availability) and BCF (bioaccumulation factors) could be used to understand Cd and Zn accumulation in Chinese cabbage.

Keywords:

• Chinese cabbage
• Cd and Zn contents
• pH
• cation exchange capacity (CEC)

Acknowledgements

The study was financed by the National Natural Science Foundation of China (approval No. 30560034), the Research Foundation for Academic Leaders in Yunnan Province (China) (approval No. 2006PY01-34) and the International Foundation of Yunnan Province (China) (approval No. 2002GH14). I wish to thank Professor Michael A. Fullen for his valuable comments and English writing improvement.