Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2006
Publication Date: November 15, 2006
Citation: Codling, E.E. 2006. Effects of lime, phosphorus and iron amended orchard soils on in vitro, water and 1n hno3 extractable lead [abstract]. American Society of Agronomy Meetings. Abstract #239, p. 128. Technical Abstract: There are public health concerns about the conversion of old orchard land, with a history of lead arsenate application for urban living. Chemical amendments such as phosphorus and iron have been shown to be effective in reducing water-extractable lead from soils contaminated from lead paint, leaded gasoline and from Zn and Pb smelters. A laboratory study was established to test the effects of lime (CaCO3), P and Fe amendments on the bioaccessibility of Pb in two orchard soils, Thurmont (Oxaquic Haplidults) and Burch (Aridic Haploxerolls), both with histories of lead arsenate application. Addition of 1.0 and 1.5 g kg-1CaCO3 were used to treat Thurmont and Burch soils, respectively. One percent Fe as [as Fe (OH)3] and 43.9 g kg-1 P (as KH2PO4) were added to the soils. Each treatment was replicated three times and incubated at field capacity for 60 weeks. Samples were taken at 2, 16 and 60 weeks for pH and water-extractable Pb; in vitro Pb and 1 N HNO3-extractable Pb were determined only in the samples taken at 60 weeks. The – lime+ Fe treatment increased soil pH from 4.16 to 6.05 and from 5.08 to 7.4 in the Thurmont and Burch soils, respectively. Iron application increased water-extractable Pb in both soils. This increase may have resulted from formation iron phosphate which releases Pb in solution. The P + Fe treatments were the most effective in reducing in vitro Pb in both soils. For example, the in vitro Pb concentration was reduced 24 and 50% for the –lime + P + Fe treatments and 28 and 42 % for the + lime + P + Fe in the Thurmont and Burch soils, respectively. There was a 3-5 % increase in the 1N HNO3 extractable Pb for the + P + Fe treatments with or without lime for both soils. The Fe + P treatment was very effective in reducing in vitro Pb but not the Pb extracted by water and 1N HNO3.