Beaches with monazitic sands show high natural radiation, and the knowledge of this radiation is fundamental to simulate the effects of natural terrestrial radiation on biological systems. Monazite-rich sand from a beach in the southeastern Brazil were collected and analyzed by X-ray fluorescence, X-ray diffraction, and magnetic susceptibility. The natural terrestrial radiation of the beach sand showed a positive correlation with the Th and Y elements, which are closely associated with Ce, Nd, Ca, and P, suggesting that this grouping is mainly associated with local natural radiation. Based on the sand characterization, a physical simulator of natural gamma radiation was built with parameters similar to those of the monazite beach sand, considering areas with high natural radiation levels. The simulation revealed that the natural radiation of the monazite sands has a significant effect on reducing the growth of the bacteria strains of E. coli and S. aureus present in the beach sand, with a reduction of 23.8% and 18.4%, respectively.

中文翻译：

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巴西东南部海滩独居石砂及其相关细菌物种的物理化学特征。

独居石沙滩表现出较高的天然辐射，而了解这种辐射对于模拟天然陆地辐射对生物系统的影响至关重要。收集来自巴西东南部海滩的富含独居石的沙子，并通过 X 射线荧光、X 射线衍射和磁化率进行分析。滩沙的自然地面辐射与Th、Y元素呈正相关，与Ce、Nd、Ca、P密切相关，表明该组群主要与局地自然辐射有关。基于沙子特征，考虑到自然辐射水平较高的区域，构建了一个自然伽马辐射物理模拟器，其参数与独居石海滩沙子的参数相似。