Effects of chromium (VI) on extractability and plant uptake of fluorine in agricultural soils of Zhejiang Province, China

In view of combined chromium and fluorine pollution in soils of coastal areas of China, the interactions between chromium and fluorine in soil-crop systems were studied using chemical extraction and pot culture methods. Regression analyses of the experimental results indicated that there were different correlation relationships between added chromium and extracted fluorine in the soils and the absorption of fluorine in rice and radish seedlings. Water-soluble and exchangeable fluorine in the soils and the absorption of fluorine in rice seedlings decreased with increasing chromium addition, when soil fluorine concentrations were low. When soil fluorine was high, water-soluble and exchangeable fluorine in the soils, and the absorption of fluorine by radish seedlings, increased with increasing chromium addition. It was preliminarily concluded that chromium could not only induce fluorine deficiency, but also augment fluorine toxicity in soil-crop systems.