Toxic Elements in Soil and Rice in Ecuador

The concentration of trace toxic metals (Cr, Zn, As, Pb, Cd, Cu, and Ni) in soil rice plants, including the stems, leaves, grain, from main rice-producing provinces Ecuador, was determined. Additionally, soils were analyzed to determine their properties, composition, total content, bioavailable fraction, geochemical fractions elements. Approximately 30% samples case Cr Cu 10% Ni exceeded legal thresholds for Ecuador. Moreover, approximately 4% 13% samples, respectively, threshold value 100 mg kg−1 proposed these two elements several international regulations. Concentrations Cd below values established both by Ecuadorian laws other countries. concentrations plants did not correlate linearly with metal soil, nor bioavailability. However, bioconcentration factors Ni, Zn could be predicted bioavailability a power law exponents ranging −0.724 −1.625, which is typical accumulator where homeostasis plays an important role.