Islam, K.R., Ahsan, S., Barik, K. et al. Water Air Soil Pollut (2013) 224: 1451. doi:10.1007/s11270-013-1451-2
Biosolids are nutrient-rich waste products often used as soil amendments. To evaluate the impact of repeated application of biosolids on heavy metal accumulation and lability, composite soils (at 0–15- and 15–30-cm depths) were collected from 0-, 2-, 5-, and 25-year biosolid-applied Genesee silt loam (fine loamy, mixed, nonacid, mesic Typic Udifluvent). While the biosolid application did not influence the pH, the electrical conductivity and heavy metal concentration varied significantly. Among the heavy metals, the concentration of total and residual cadmium (Cd) was the highest (3 and 2.8 times), and copper (Cu) was the lowest (1.3 to 1.2 times) in the 25-year biosolid-applied field than in the control. The exchangeable chromium (Cr) concentration was the highest (6 times), and Cu was the lowest (1.9 times) in the 25-year biosolid-applied field as compared with the control. The lability of Cr, lead (Pb), cobalt (Co), zinc (Zn), Cu, nickel (Ni), and arsenic (As) significantly increased by 20, 11, 9, 9, 8, 6, and 4 %, respectively, in the 25-year biosolid-applied field compared to the control field. The extractable Pb, As, Zn, and Cu concentrations were significantly higher at 0–15 cm than at 15–30 cm depth. The labilities of Pb, Cu, and Ni were significantly varied between depths. Biosolids × depth significantly influenced the total As and residual As, Cu, and Pb concentrations. All the heavy metals except total and residual As significantly correlated with the total organic carbon. Results suggest that the accumulation and lability of heavy metals are related to complexation of heavy metals with organic carbon in response to years of biosolid application.