## 3 Results  
This analysis was conducted using Stata 17 software at 95% ci and 5% significance level. Descriptives statistics of chemical elements detected in clay soil that is consumed by women of childbearing age in Tshwane District, Gauteng Province were also described (see Table 2 below). In all the 39 clay soil samples analysed, lithium ranged from 12 to 38 mg/kg vanadium ranged from 77 to 864 mg/kg, manganese ranged from 33 to 742 mg/kg, cobalt ranged from 7 to 20 mg/kg, copper ranged from 21 to 58 mg/kg, uranium ranged from 3 to 10 mg/kg, beryllium ranged from 0.2 to 5 mg/kg, chromium ranged from 125 to 320 mg/kg, lead ranged from 13 to 29 mg/kg, nickel ranged from 26 to 67 mg/kg, barium ranged from 85 to 291 mg/kg, bismuth ranged from 0.2 to 1.8 mg/kg, strontium ranged from 18 to 113 mg/kg, arsenic ranged from 4.7 to 14 mg/kg, and zinc ranged from 33 to 122 mg/kg. Cadmium was detected in only six out of 39 clay soil samples analysed, with the range between 0.1 mg/kg and 0.2 mg/kg, but the remaining 33 samples contained cadmium at quantities below 0.1 mg/kg. Mercury and silver concentrations detected in the clay soil samples were found to be below 0.1 mg/kg in all 39 samples that were analysed (refer to Table 2 below). Chemical composition of clay soil consumed by women of childbearing age in Tshwane District. The average values for each chemical parameter were calculated. The concentrations of chemical elements detected in the clay soil commercialised in Marabastad, distributed in all areas of Tshwane, and eaten by women of childbearing age and pregnant women, contained vanadium as the trace element with the highest chemical content with an average concentration of 575 mg/kg, followed by manganese with an average concentration of 396 mg/kg and chromium with an average concentration of 249 mg/kg. The remaining  
Figure 4: Geographic locations where clay soil samples were collected. trace elements were reported at levels below 100 mg/kg, starting with zinc with an average concentration of 72 mg/kg. Strontium, nickel and copper were detected at quantities above 50 to 40 mg/kg. Lead and lithium were detected in the samples at levels above 20 mg/kg, followed by cobalt, with an average concentration of 13 mg/kg. Barium and uranium were reported at concentrations below 10 mg/kg. Bismuth was the lowest detected trace element with a concentration lower than 1 mg/kg (see Figure 5). \begin{table}
\begin{tabular}{p{113.8 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Chemical Elements** & **Mean** & **Std Dev** & **Min** & **Max** \\ \hline
**Li** & 23 & 6 & 12 & 38 \\ \hline  
** & 7 & 2 & 3 & 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Descriptive statistics of chemicals analysed in clay soil. Figure 5: Mean concentrations per trace element detected in clay soil. The recommended standards for trace elements intakes were consulted to determine the potential health risks linked with ingestion of clay soil amongst women of childbearing age (refer to Table 3) adopted from a published study [19]. Chemical composition of clay soil in Tshwane District, Gauteng Province. The thirty-nine clay 39 samples received from the participants differed in colour, texture, taste, and particle size Some samples were extremely hard; some were soft, dusty, and rock-like; and some were brittle. The concentrations of chemical elements detected in the samples were recorded independently per sample in mg/kg (refer to Figures 6-13 below). Figures 6 and 7 above indicate that vanadium was detected in high quantities for all samples except samples 21, 24, and 39--in other words, in 36 out of 39 samples. Manganese was the trace element second most frequently detected, not being detected in samples 21, 24, 25, 30, and 39, and exceeding all comparable parameters in samples 14, 19, and 28. The concentrations of chromium were close to those of manganese for this set of comparisons. Barium concentrations were lower than those of vanadium, chromium, and manganese in similar samples.