Assessment of Vegetables and Soils from Minjingu Village-Tanzania using WDXRF Technique

Abstract

Wavelength dispersive x-ray fluorescence (WDXRF) spectrometer was used to analyze heavy metal concentration in soils and vegetables. The soil and vegetable samples were randomly collected from Minjingu village of Manyara region in Tanzania. The results indicate the soils to be contaminated with heavy metals with mean concentrations of 53±0.4 For Mn, 40±0.2 for Sr, 2059±4.2 for Fe, 760±2.7 for Al, 12±0.3 for Cs and 4±0.04 for Ni in mg/kg which was above the Maximum Tolerable Limits (MTLs). Except Cl was below MDL. While vegetables recorded the mean concentrations of 60±1.2 for Mn, 68±0.1 for Sr, 620±2.36 for Fe, 284±1,13 for Al, 56±0.5 for Cs, 13±0.1 for Ni and 714±0.7 for Cl in mg/kg. The reference and experimental results of soil and vegetables revealed that the optimized machine has given the best results, where the experimental data was very close to the reference values The reference material of soil 7 and International Atomic Energy Agency (IAEA) 395 for vegetables shows the deviation of less than 2%.The Minimum Detection Limit (MDL) for vegetables and soil of the WDXRF spectrometer was obtained under low back ground for different matrix effects. There were high correlation coefficient of heavy metals in soils and vegetables at 99% level. The findings indicate that Minjingu soils and grown vegetables were highly contaminated with heavy metals mainly from soils and polluted air, at levels able to pose detrimental health effects to the consumers. Thus need of regular monitoring of the grown vegetables around phosphate mines is recommended.