Capture and accumulation of perchlorate in lettuce. Effect of genotype, temperature, perchlorate concentration, and competition with anions

Various studies have evaluated the accumulation of ClO4− in lettuce (Lactuca sativa), but very few have dealt with the variables that can interfere with its capture. The present study evaluates the transfer of ClO4− in two L. sativa varieties: butter head (L. sativa var. capitata) and cos lettuce (L. sativa var. crispa) under hydroponic conditions. The ClO4− concentrations used correspond to levels (1 and 2 mg L−1), measured in irrigation water in the Iquique region in the north of Chile. Results indicate that the capture of ClO4− is dependent on its concentration, lettuce genotype, and temperature. The butter head variety accumulates the highest perchlorate concentrations. Anion competition involving NO3− (16 and 48 mM), Cl− (23 and 56 mM), and SO42− (10 and 20 mM) was evaluated, being NO3− (48 mM), the most significant competition reducing the concentration of ClO4− in tissues of L. sativa varieties.