Application of ICP-mS and AFS to detecting heavy metals in phosphorus fertilizers

Abstract

In order to investigate heavy metals in phosphorus fertilizers in China, 159 samples of phosphorus fertilizers including imported fertilizers and domestic fertilizers were collected from fertilizer markets, and the contents of heavy metals were determined by ICP-MS and AFS after microwave digestion. The results showed that the phosphorous fertilizers contained certain amount of heavy metals, and there was great variability in the contents of heavy metals. The mean contents of Cd, Cu, Zn, Cr, Pb, Ni, As and Hg were 0. 77, 35.6, 102.7, 24. 1, 16.6, 15.4, 19.4 and 0. 08 mg kg-1 fertilizer, respectively; based on the calculation of P2O5, the mean contents of above heavy metals were 4. 48, 258. 4, 767. 4, 190. 0, 151.3, 134. 5, 155. 8 and 8. 79 mg kg-1 P2 O5, respectively. The contents of heavy metals Cd, Cr, Pb, As and Hg in the tested samples accord with the ecological index of arsenic, cadmium, lead, chromium and mercury for fertilizers (GB/T 23349-2009), with the exception of Cd in one imported sample of diammonium phosphate and As in one sample of mono-ammonium phosphate. Analyzing the contents of heavy metals in imported fertilizers, the Cd contents in imported fertilizers was ranged from 0. 02 to 27. 2 mg kg-1 fertilizer, the mean and median Cd contents in imported fertilizers were 3. 20 and 0. 41 mg kg-1 fertilizer, respectively. And the Cu, Cr and Hg contents in the imported fertilizers were higher than that of domestic fertilizers, the mean contents of Cu, Cr and Hg in imported fertilizers were 39. 4, 26. 6 and 0. 47 mg kg-1 fertilizer, respectively.