Applications of X-Ray Analysis: Tanzanian Case Studies

Chapter 1. The samples of both maize and soil were prepared and analyzed using Energy Dispersive X-rays Fluorescence (EDXRF) with the objective of investigating the elemental concentration levels. Most of the elements in both soil and maize were detected with high concentration levels.

Chapter 2. The mean concentrations of the analyzed elements were compared to the maximum tolerable levels (MTLs) set by international organizations. The mean concentrations of Ca, Se, Zn, As, Cr, and Cd were higher than their MTLs while, the mean concentrations of Cu and Ni were lower than their MTLs for samples from all fish markets.

Chapter 3. The Health Risk Index (HRI) values for Sr, Ni and Fe in vegetables exceeded the maximum threshold limits (HRI>1) set by United States Environmental Protection Agency (USEPA). The findings of this work indicates that soils and vegetables grown, particularly cowpea leaves, spinach and Chinese cabbages were extremely contaminated at levels able to pose detrimental health effects to the consumers. Therefore the consumption of cowpea leaves, spinach and Chinese cabbages should be reduced to the maximum if not abandoned. But limited quantities of Ethiopian mustard and sweet potato leaves can be taken while immediate steps are taken to reduce anthropogenic activities at the polluting site. This situation makes the regular monitoring of the grown vegetables a compulsory act.

Chapter 4. The results of vegetables show the deviation of less than 2%.The Minimum Detection Limit (MDL) for vegetables and soil of the Wavelength dispersive x-ray fluorescence (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.