Soil heavy-metal distribution and transference to soybeans surrounding an electroplating factory

Abstract

Heavy-metal pollution of soils and crops is an often overlooked issue that is becoming increasingly serious. A study of soybean production on soils surrounding an electroplating factory in the Yangtze River Delta of China was conducted to identify heavy-metal mobility and spatial distribution in soils, their transfer to plant tissues, and subsequent changes in plant enzymatic activities. The results indicated systematic Ni and Zn contamination of soils and soybean crops in this region. Zinc and Cu were distributed along a gradient and their concentrations in soil and soybean foliage were closely related, suggesting that their similar spatial distribution in soil and soybean foliage was affected by factory contamination. The combinations of soil heavy-metal pollutants influenced the total amounts of heavy-metal pollutants in soybean foliage. In soybean foliage, the activity of peroxidase was significantly correlated with Ni, Cu, Zn, and their ionic impulsion (an index of plant-soil pollution). Peroxidase activity may be an appropriate biomarker for heavy-metal accumulation in soybean foliage.

Keywords:

• Accumulation
• enzymatic activity
• heavy-metal contamination
• soybean foliage
• spatial distribution

Acknowledgements

The authors would like to thank X.Y. Zhang for his valuable assistance in mapping the figures. The detailed comments made by an anonymous reviewer greatly improved the manuscript. This study was financially supported by the National Basic Research Program of China (2002CB410810).