Figure 5 (a)–(e) Histograms of Pb element distributions from Fig. 4: (a) control sample, (b) with 1% MACl, (c) 3% MACl, (d) 5% MACl and (e) 7% MACl. (f) FWHM values corresponding to the MACl concentrations in (a)–(e), derived through Gaussian fitting. Additional values related to Gaussian fitting are provided in Table 2.