Analysis of Radium Isotopes in Surface Waters nearby a Phosphate Mining with NORM at Santa Quitéria, Brazil

Abstract

The radium isotopes 226 Ra and 228 Ra were analyzed in surface water at six points in the neighborhood of a mine of phosphate, associated with uranium, in the region of Santa Quitéria, state of Ceará, Brazil. Water samples were collected during twenty months, filtered and the concentrations of activity determined in the soluble and particulate phases. The results were analyzed using the Principal Component Analysis (PCA) for ordination of environmental data, and also by ANOVA, Tukey and Z tests to compare sets of data considering the radionuclides, the two analyzed phases and the six collecting points. The PCA identified four groups that included all collecting points, using aggregation features such as radionuclide and analyzed phase. The first group is composed by the samples of 226 Ra in the soluble phase; the second group by samples of 226 Ra in the particulate phase; the third one by 228 Ra in the soluble phase, and finally, the fourth group by 228 Ra in the particulate phase . This last group has two discrepant points (01 and 06). Statistical analysis identified differences between the concentrations of activity of radionuclides ( 228 Ra higher than 226 Ra) and in analyzed phases (soluble phase higher than the particulate one) but showed no differences between sampled points.