Int. J. Environ. Res. Public Health 2009, 6 Table 1. Water-extractable metals fractions (mg·kg-1) relative to the total metal concentrations (mg·kg-1) in the bulk compost at different temperatures for Zn, Pb, Cu and Cd. Pb Total Water Wm/Tm (Tm) extractable ×100 (Wm) (%) Total Water Wm/Tm (Tm) extractable ×100 (Wm) (%) 4.03 2.44 3.05 2.43 5.21 4.93 3.25 2.56 2.07 2.14 2.60 2.84 3.38 2.44 1.83 2.71 2.33 2.09 3.38 2.56 2.44 3.14 3.15 2.99 9.22 9.27 8.90 9.29 7.26 8.96 Cd Total Water Wm/Tm (Tm) extractable ×100 (Wm) (%) 0.13 ±0.003 0.13 ±0.003 0.22 ±0.001 0.22 ±0.001 0.15 ±0.005 0.15 ±0.005 0.13 ±0.003 0.13 ±0.003 0.22 ±0.001 0.22 ±0.001 0.15 ±0.005 0.15 ±0.005 0.13 ±0.003 0.13 ±0.003 0.22 ±0.001 0.22 ±0.001 0.15 ±0.005 0.15 ±0.005 0.13 ±0.003 0.13 ±0.003 0.22 ±0.001 0.22 ±0.001 0.15 ±0.005 0.15 ±0.005 0.13 ±0.003 0.13 ±0.003 0.22 ±0.001 0.22 ±0.001 0.15 ±0.005 0.15 ±0.005 0.003 0.001 0.002 0.002 0.003 0.009 0.001 0.002 0.003 0.002 0.004 0.004 0.001 0.001 0.003 0.002 0.003 0.002 0.002 0.002 0.004 0.004 0.003 0.003 0.012 0.009 0.004 0.005 0.001 0.003 2401 2.30 0.77 0.91 0.91 2.00 6.00 0.77 1.54 1.36 0.91 2.67 2.67 0.77 0.77 1.36 0.91 2.00 1.33 1.54 1.54 1.82 1.82 2.00 2.00 9.23 6.92 1.82 2.27 0.67 2.00 1.57 1.41 0.92 1.80 1.93 3.61 2.01 4.91 2.63 9.94 4.68 13.25 5.92 3.25 0.30 1.14 1.20 2.65 1.07 1.02 0.47 3.29 1.63 3.49 1.69 1.87 0.47 2.46 1.76 6.63 0.13 ±0.01 4.33 ±0.26 4.33 ±0.25 7.50 ±0.18 4.33 ±0.26 2.17 ±0.06 0.13 ±0.01 4.33 ±0.26 4.33 ±0.25 7.50 ±0.18 4.33 ±.26 2.17 ±0.06 0.13 ±0.01 4.33 ±0.26 4.33 ±0.25 7.50 ±0.18 4.33 ±0.26 2.17 ±0.06 0.13 ±0.01 4.33 ±0.26 4.33 ±0.25 7.50 ±0.18 4.33 ±0.26 2.17 ±0.06 0.13 ±0.01 4.33 ±0.26 4.33 ±0.25 7.50 ±0.18 4.33 ±0.26 2.17 ±0.06 0.006 0.110 0.099 0.054 0.078 0.046 0.009 0.052 0.102 0.048 0.125 0.077 0.004 0.060 0.004 0.079 0.091 0.097 0.002 0.031 0.022 0.050 0.067 0.078 0.009 0.114 0.065 0.860 0.098 0.163 4.62 2.54 2.29 0.72 1.80 2.12 6.92 1.20 2.36 0.64 2.89 3.55 3.07 1.39 0.09 1.05 2.10 4.47 1.54 0.72 0.51 0.67 1.55 3.59 6.92 2.63 1.50 1.15 2.26 7.51 0.77 ±0.09 0.82 ±0.05 0.82 ±0.09 0.70 ±0.13 0.73 ±0.06 0.67 ±0.04 0.77 ±0.09 0.82 ±0.05 0.82 ±0.09 0.70 ±0.11 0.73 ±0.06 0.67 ±0.04 0.77 ±0.09 0.82 ±0.05 0.82 ±0.09 0.70 ±0.01 0.73 ±0.06 0.67 ±0.04 0.77 ±0.09 0.82 ±0.05 0.82 ±0.09 0.70 ±0.13 0.73 ±0.06 0.67 ±0.04 0.77 ±0.09 0.82 ±0.05 0.82 ±0.09 0.70 ±0.13 0.73 ±0.06 0.67 ±0.04 Cu 0.031 0.020 0.025 0.097 0.038 0.033 0.025 0.029 0.097 0.015 0.019 0.019 0.260 0.200 0.015 0.019 0.017 0.014 0.026 0.021 0.020 0.022 0.023 0.020 0.071 0.076 0.073 0.065 0.530 0.060 Compost type CHHW-U CHHW-T CMSW-U CMSW-T CAGW-U CAGW-T CHHW-U CHHW-T CMSW-U CMSW-T CAGW-U CAGW-T CHHW-U CHHW-T CMSW-U CMSW-T CAGW-U CAGW-T CHHW-U CHHW-T CMSW-U CMSW-T CAGW-U CAGW-T CHHW-U CHHW-T CMSW-U CMSW-T CAGW-U CAGW-T Zn Total Water Wm/Tm (Tm) extractable ×100 (Wm) (%) 10 °C 3.38 ±0.75 0.053 2.83 ±0.53 0.040 6.00 ±0.29 0.055 1.67 ±0.89 0.300 2.33 ±0.04 0.045 0.83 ±0.44 0.300 29 °C 3.38 ±0.75 0.068 2.83 ±0.53 0.139 6.00 ±0.29 0.158 1.67 ±0.89 0.166 2.33 ±0.04 0.109 0.83 ±0.44 0.110 40 °C 3.38 ±0.75 0.200 2.83 ±0.53 0.092 6.00 ±0.29 0.018 1.67 ±0.89 0.019 2.33 ±0.04 0.028 0.83 ±0.44 0.022 60 °C 3.38 ±0.75 0.036 2.83 ±0.53 0.029 6.00 ±0.29 0.028 1.67 ±0.89 0.055 2.33 ±0.04 0.038 0.83 ±0.44 0.029 80 °C 3.38 ±0.75 0.057 2.83 ±0.53 0.053 6.00 ±0.29 0.028 1.67 ±0.89 0.041 2.33 ±0.04 0.041 0.83 ±0.44 0.055 CHHW-T, CMSW-T, CAGW-T = composted household, municipal and agricultural solid wastes via turned production procedures; CHHW-U, CMSW-U, CAGW-U = composted household, municipal and agricultural solid wastes via unturned production procedures. Pearson correlations (Table 2) showed that, in all cases, the water-extractable fraction of Zn was negatively related to temperature with coefficient (r) in the range of –0.067 to –0.445 while Cd, Cu and Pb showed positive correlations (r = 0.137 to 0.893) in composted household and municipal solid wastes. However, Pb and Cd gave negative correlations in the case of composted agricultural wastes that were not turned during production. The coefficients for Cu and Cd were higher than the values obtained for Pb and Zn except in composted agricultural wastes prepared by turning (CAGW-T) where Pb gave the highest value. In composted agricultural wastes, prepared without turning (CAGW-U), only Cu gave positive correlation (r = 0.185) while the other metals (Cd, Pb and Zn) gave negative correlations (r = –0.054 to –0.360). Simulation data (Tables 3 and 4) showed that a steady temperature rise by 0.1 °C could result in the release of water-extractable fraction from bulk compost material in the range of 2 ×10-5 to 3 ×10-4 mg·kg-1 and a change from 0.1 to 1.5 °C could lead to a net increase of water-extractable fraction from 0.13 to 168%, which varied with metal type.