Assessment of elemental composition and distribution of some fertilizers used in Nigeria
Using energy dispersive x-ray fluorescence (EDXRF) technique, the study qualitatively and quantitatively assessed the elemental distribution of commonly used fertilizers in Nigeria. A total of 15 chemical elements, K, Ca, Mn, Fe, Ni, Cu, Zn, As, Pb, Br, Rb, Sr, Zr, U and Th, per sample were detected. The K peaked in all the samples with Th was the least in concentration. Due to the toxic and carcinogenic nature of arsenic and lead, their concentration levels were compared with the internationally acceptable concentration limits. The measured range and mean concentration levels of As and Pb in the samples analyzed were found to be [102-193] 173±20ppm and [215-275] 255±17 ppm, respectively. The results are respectively 3 and 2.5 orders of magnitude, higher than the World Fertilizer Metal Standards recommended limitst. The MOP fertilizer has the highest mean concentration levels for both As and Pb, followed by SSP fertilizer, which recorded As and Pb concentration level s of 161±50 ppm and 231±68 ppm, respectively. In addition, the Pb/As ratios are in the range 1.33-1.50, which is an indication of good correlation between the assessed toxic elements.
Keywords: chemical elements, fertilizers, concentration levels, PBTs, chemical toxicity