Copper, Zinc, Arsenic And Fluorine In Some Paddy Rice Soils In Fujian Province And Their Transfer Into Rice Grains

The total and available contents, the availability degree and the transfer characteristics to rice grains of copper, zinc, arsenic and fluorine in some paddy soils (≤ 15cm) collected from some paddy fields in the suburbs of Quanzhou and Zhangzhou cities of Fujian Province were studied in order to lay a foundation for the establishment of soil environmental quality standards of Fujian province. The major results were as follows:1. The paddy paddy fields in these regions were not apparently polluted with As. However, the concentrations of total Cu and Zn in some of the soils exceeded the corresponding limits of environmental quality standard for agricultural soils. The available contents of Cu, Zn, As and F were significantly correlated with total soil Cu, Zn, As and F, respectively. There were significant and positive correlations between total Cu and free Fe, total Zn and clay and free Fe, total As and free Fe, total F and clay, respectively, which suggested that clay and free Fe oxides favor the accumulation of Cu, Zn and As in the paddy rice soils.2. The availability degree (AD, ratio of total content to available content) of Zn, As and F were affected by the contents of total elements, organic matter, free Fe and clay, as well as soil pH. The AD of Zn positively correlated with organic matter content while negatively correlated with total Zn. The AD of As positively correlated with organic matter but negatively correlated with free Fe. The AD of F was positively correlated with total F and pH while negatively correlated with free Fe. These significant correlations are important basis for regulating the bio-availability and toxicity of these elements in paddy soils.3. The concentrations of Cu, Zn, As and F in the unpolished rice grains were 2.31 — 5.68 mg.· kg^-1,15.28⁴5.23 mg.· kg^-1,0.056-0.382 mg.· kg^-1, 3.83-11.45 mg.· kg^-1, respectively. The concentrations of Cu, Zn and As in the rice grains were all below the limits of food hygiene standards of China while that of F exceeded the limit. The concentrations of Cu, Zn and As in the rice grains did not significantly correlated with the total and available Cu in the soils. However, the F concentrations in rice grains were significantly correlated with both total and available F in the soils.4. The soil-to-rice grain transfer factors (TF) of the four elements (both total and...