Tracer studies of behavior of zinc and copper in soil-plant systems using stable isotopes

Stable isotopes (SI) of Zn and Cu were found to be good tracers for the study of behavior of the metals in soil-plant systems. After wet digestion of soils and plants with the acid mixture, iron was eliminated from the digestion solution by extracting with MIBK-HCl. Then, Zn and Cu were isolated from the solution using anion exchange resin (AGl). The ratio of 63Cu/65Cu was determined by thermal ionization mass spectrometry (TIMS) with relative standard deviation of 0.60%. The ratio of 64Zn/66Zn was determined by inductively coupled plasma mass spectrometry (ICP-MS) with a relative standard deviation of 0.94%. Pot experiments were carried out to study the effect of sewage sludge application to the soil behavior of Zn and Cu in soil-plant system using SI of the metals. It was found that 66ZN and 65Cu tracers moved more than 1 cm within 4 months after the application and maize absorbed 66Zn of 40 μg/plant and 65 of 2 μg/plant for 2 months, respectively