## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**ID** & **Kaolinite** & **Illite** & **Smctite** & **Corrensite** & **Halloysite** \\ \hline MIW & tr & +++ & & \\ \hline MIR & +++ & & tr & \\ \hline RW & +++ & + & tr & \\ \hline RR & +++ & + & tr & \\ \hline MZW & +++ & + & tr & \\ \hline MZY & +++ & & & tr \\ \hline MZR & +++ & & tr & \\ \hline MXR & +++ & & & \\ \hline MER & +++ & & tr & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mineralogical composition of clay fraction of studied samples. Figure 6: Relative mineralogical composition of sand and silt fractions of studied samples. kaolinite clays could be used as antacids [59]. Thus, kaolinite is a gastrointestinal protector [60,61]. Their therapeutic action is based on their high specific area and adsorption capacity [62]; they adhere to the gastric and intestinal mucosa and protect them, and can absorb toxins, bacteria, and even viruses [63]. However, consumption and prolonged exposure can lead to health complications, and their toxicity is generally related to the presence of quartz [64,65], which was the predominant mineral in the sandy fraction. Illite and smectite reduce mucus destruction by bacteria and improves nutrient absorption [66]. It is also reported a great capacity of adsorption of _S. enteritidis, E. coli, V. cholerae, C. jejuni, C. difficile, Shigella sonnei_, eliminating up to 90% of their viral particles [67], as well as on the cure of acute diarrhea [68]. However, prolonged consumption of these clays can trigger health problems, as previously described by [34,68,69,70]. The chemical composition statistical summary of sand and silt fractions is presented in Table 3. A 1-way ANOVA test was performed to assess significant differences between the two fractions. The chemical composition presented significant differences between sand and silt fractions on variables Al, Ba, Cr, Fe, Mg, Mn, Ni, P, Pb, Rb, Si, Sr, Ti, V, and Zn (\(p\) < 0.01, except for Mn with \(p\) < 0.02). In general, the silt fraction revealed the highest concentration of most essential and potentially toxic elements, except for Na and P.  
Multiple benefits for the body are ascribed to Ca; however, high intakes (Recommended daily dose (RDD) 1200 mg/kg) can cause renal failure, vascular and soft tissue calcification in fetuses, hypercalciuria, heart disease, and kidney stones [71,72]. Studied samples presented mean concentrations of 2414 and 2235 mg/kg in sand and silt fractions, respectively. The function K in humans is closely related to Na, an essential nutrient involved in fluid, acid, and electrolyte balance and is required for normal cellular function [73,74]. Gastrointestinal effects (e.g., discomfort, mucosal lesions, and sometimes ulceration) and heart failure can be linked to high K (RDD 5000 mg/kg) [74] and Na (2000 mg/kg) [75,76] ingestion. In this study, high concentrations of K and Na were found in both fractions (Table 3). One of the known key factors for geophagic materials consumption is Fe content [57]. Studies by [13,19] reported Fe supplementation has a motivation for pregnant women to practice geophagy in Namibia and in other African countries and