highly significantp < 0.001
For example, Pb shows a highly significant correlation with Cd (r = 0.914, p < 0.001), Cr (r = 0.678, p < 0.001), Cu (r = 0.784, p < 0.001), Ni (r = 0.679, p < 0.001), Sr (r = 0.459, p < 0.05), and Zn (r = 0.842, p < 0.001).