Groundwater Quality During Thirty-Five Years of Monitoring Mined Land Reclaimed with Biosolids.

Application rates of bioslids for mined land reclamation is often higher than the agronomic rate to improve both fertility and physical characteristics of the soil. However, long term of biosolids application for reclamation can potentially result in leaching of biosolids constituents to ground water. We analyzed 35 years of ground water monitoring data from 14 strip-mined fields located in Fulton County, Illinois. Seven of the fields received continous application of biosolids at cumulative rates of 801 – 1815 Mg ha^-1 equivalent to 25 - 44 dry Mg ha^-1 yr^-1 and the other seven fields received chemical fertilizer at agronomic rate. Groundwater from monitoring wells located in each field were sampled monthly between 1972 and 1986, and quaterly between 1987 and 2006 and analyzed for N, P, metals and other parameters. The long-term application of biosolids did not increase groundwater concentrations of P, copper, lead, cadmium, nickel, chromium, and mercury, and most concentrations were lower than the Illinois groundwater standards. Groundwater nitrate was below regulated limit during the monitoring period, but repeated application of biosolids at higher than agronomic rate resulted in increased trend. Some elevated Zn concentrations in groundwater were observed, but were associated with high metal bisoolids applied before promulgation of the Part 503 rule. The data suggests that long-term application of biosolids even at greater than agronomic rate does not result in groundwater contamination with respect to biosolids borne N, P, and metals regulated in the Part 503 Rule.