Fig. 11

Calibration plot of individual heavy metal treatments between fluorescent intensities in CTCF and heavy metal concentrations in ppb. The fluorescent intensities have been obtained for samples containing metal ion concentrations in between 1 to 6 ppb. The treatments with Ni²⁺, Pb²⁺, Zn²⁺ and Cd²⁺ are shown in black colour bars, orange colour bars, blue colour bars and red colour bars in order. The R² values for Ni²⁺, Pb²⁺, Zn²⁺ and Cd²⁺ trends are as 0.3825, 0.9785, 0.9761 and 0.9809. The error bars represent standard mean differences of three independent biological treatments. A single asterisk (*) represents a P value less than 0.05 (P < 0.05), indicating statistical significance at the 0.05 level. Double asterisks (**) represent a P value less than 0.01 (P < 0.01), indicating statistical significance at the 0.01 level. Triple asterisks (***) represent a P value less than 0.001 (P < 0.001), indicating statistical significance at the 0.001 level. Quadruple asterisks (****) represent a P value less than 0.0001 (P < 0.0001), indicating statistical significance at the 0.0001 level