A positive and significant correlation was found between the content of Cd extractable with DTPA in
both soils and the Cd content in plant, after both 3 h and 60 days of soil incubation (Table 5). Severalauthors have reported that DTPA is one of the best Cd extractants for predicting Cd uptake by plants from contaminated soils (O?Connor 1988; Singh and Narwall 1984). Other authors have suggested that a CaCl 2 solution is a preferred extractant for Cd due to highly significant correlations observed between Cd uptake by plants and CaCl 2 extractable concentrations (McLaughlin and others 1997; Sauerbeck and Styperek 1985).