Concentrations of Ni and Co in crop plants cultivated in Northern Chile

Abstract

This paper provides an overview of nickel and cobalt concentrations found in the north of Chile especially as it relates to exposure of heavy metals to humans and animals through food; to help creating a database for estimating the Ni and Co content in the native farmer's diet of South America. The information include levels of nickel and cobalt measured in a number of different types of vegetables (potato, broad bean, onion and alfalfa) exposed to a natural environmental contamination (especially in relation to volcanic activity and mineral composition of the soil). The simultaneous determination of Ni and Co at pH 9 after adsorptive accumulation of the respective complex with dimethylglyoxime (DMG) at the mercury drop electrode is made by adsorption differential pulse voltammetry (ADPV). The values, expressed in fresh weight, varied from 9-160 μg Kg-1 for Ni and from 1-127 μg Kg-1 for Co. At the present time, there are no established legal standards for nickel and cobalt in any vegetables in Chile.