| Copper-based fungicides are among the most widely used pesticides, particularly in orchards. The use of copper-based fungicides leads to an accumulation of copper（Cu） in orchard soils, potentially causing adverse effects to the soil environment and ecological system. Bordeaux mixture（also called Bordo Mix） is a mixture of copper（Ⅱ） sulfate（CuSO4） and slaked lime used as a fungicide in orchards. In order to determine the dynamic of the residue of copper ion, the active substance of Bordeaux mixture, in apple fruit and soil, and to assess environmental risk of the application of this fungicide. Bordeaux mixture 80% WP residue trials were carried out in Xuzhou and Shijiazhuang. Bordeaux mixture 80% WP applied at recommended amount left low levels of residue（<2mg·kg-1） on apple fruits, which is much lower than the maximum copper residue amount（10 mg·kg-1） allowed in food in accordance with China National Standard for Copper Residue in Food（GB 15199—1994）. The original deposition of copper ion in orchard soils of Xuzhou and Shijiazhuang were 36.9 mg·kg-1 and 28.0 mg·kg-1, respectively. While the maximum copper ion residue in orchard soils of Xuzhou and Shijiazhuang were found to be 128.4 mg·kg-1 and 39.8 mg·kg-1, respectively, indicating that soil copper residue level was increasing with the application of Bordeaux mixture. The results of environmental risk assessment show that the copper residue level in Xuzhou orchard soil, is close to the maximum value in China Soil Quality Standard. According to the calculation only 10 years are left for safe application of Bordeaux mixture in orchard of Xuzhou. It is concluded that this copper-based fungicide should not be used in abundance in Xuzhou orchard. |
