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Diffusive gradients in thin films (DGT) for the prediction of bioavailability of heavy metals in contaminated soils to earthworm (Eisenia foetida) and oral bioavailable concentrations
- Bade, Rabindra, Oh, Sanghwa, Shin, Won Sik
- The Science of the total environment 2012 v.416 pp. 127-136
- Eisenia fetida, bioavailability, dynamic models, earthworms, heavy metals, polluted soils, prediction, soil texture
- The applicability of diffusive gradients in thin-films (DGT) as a biomimic surrogate was investigated to determine the bioavailable heavy metal concentrations to earthworm (Eisenia foetida). The relationships between the amount of DGT and earthworm uptake; DGT uptake and the bioavailable concentrations of heavy metals in soils were evaluated. The one-compartment model for the dynamic uptake of heavy metals in the soil fitted well to both the earthworm (R²=0.641–0.990) and DGT (R²=0.473–0.998) uptake data. DGT uptake was linearly correlated with the total heavy metal concentrations in the soil (aqua regia), the bioavailable heavy metal concentrations estimated by fractions I+II of the standard measurements and testing (SM&T) and physiologically based extraction test (PBET, stomach+intestine). The coefficients of determination (R²) of DGT uptake vs. aqua regia were 0.433, 0.929 and 0.723; vs. SM&T fractions (I+II) were 0.901, 0.882 and 0.713 and vs. PBET (stomach+intestine) were 0.913, 0.850 and 0.649 for Pb, Zn and Cu, respectively. These results imply that DGT can be used as a biomimic surrogate for the earthworm uptake of heavy metals in contaminated soils as well as predict bioavailable concentrations of heavy metals estimated by SM&T (I+II) and PBET as a human oral bioavailable concentrations of heavy metals.