Residual Effects of Long-term Biosolids Application on Concentrations of Carbon, Cadmium, Copper, Lead and Zinc in Soils from Two Regions of the United States

Biosolids are used to improve soil physical and chemical properties. Analysis of biosolids-amended soils from multiple regions of United States using consistent analytical methods is lacking. This Study determined long-term biosolids application on soil pH, electrical conductivity (EC), carbon, cadmium, copper, lead, and zinc concentrations in soils from two regions in United States. At one region, little difference was observed in pH and EC between biosolids-amended surface soils and control, the second region ranged from 5.46 to 7.87 and 50.2 to 402 mu S cm(-1) respectively. Trace metal levels at this region ranged from 0.76 to 3.79, 8.7 to 54.1, 15.2 to 53.9, and 26 to 207 mg kg(-1) for Cadmium, Copper, lead and Zinc respectively; with its carbon levels ranging from 14.5 to 90.0 g kg(-1). Metal levels were within the standards for residential occupation with the 40 Code of Federal Regulations (CFR) Part 503 and should not affect soil and groundwater quality.