Content and morphology characteristics of heavy metals in phosphate fertilizers in Hunan province

Phosphate fertilizer and raw material in the existing phosphate fertilizer producers in Hunan Province were sampled. According to the "ecological indexes of arsenic, cadmium, lead, chromium, mercury in fertilizer" (GB/T 23349-2009), the pollution index was evaluated. The results show that the average contents of arsenic, chromium, lead, cadmium, mercury in single superphosphate are 26.78 mg/kg, 18.86 mg/kg, 18.51 mg/kg, 1.55 mg/kg and 1.27 mg/kg respectively. The average contents of chromium, lead, arsenic, cadmium, mercury in calcium magnesium phosphate are 798.39 mg/kg, 9.78 mg/kg, 6.31 mg/kg, 0.67 mg/kg and 0.11 mg/kg respectively. The arsenic, cadmium, lead, chromium, mercury content in most phosphorus fertilizer are lower than the standard. The lead, cadmium, arsenic, chromium in single superphosphate are mainly from phosphor mine and mercury from sulfuric acid. The lead, cadmium, mercury, arsenic, chromium in calcium magnesium phosphate are mainly from phosphate. Under acidic conditions potential risks from cadmium in phosphate fertilizer for agricultural product safety exist.