Cadmium Accumulation in a Tropicalized Lettuce Variety Under Overfertilization Simulation

Cadmium (Cd) can accumulate in vegetables and enter the food chain. The production of vegetables usually uses excessive amounts of fertilizers which bring environmental and health damages. The authors investigate the relationship between fertilization with nitrogen (N), phosphorus (P), and potassium (K) and the accumulation of Cd and nitrate in lettuce of the tropicalized variety "Gloriosa." The experiment is under greenhouse conditions in a 2x2 factorial design, with the addition or not of 10 mg kg(-1) Cd to the soil, and the use of one and three times the recommended rate of N, P, and K for lettuce crop. The higher fertilization rate is related to the increase of Cd in the shoots. Gloriosa lettuce shows high Cd-accumulation capacity, especially in the shoots, evidencing great Cd-translocation. Fresh leaves reach up to 8 mg kg(-1) Cd, higher than permissible limits, but high Cd-tolerance and no visual symptoms of toxicity or reduction in biomass production. In plants grown with three times the recommended rates of N, nitrate concentrations are within the permissible limits for leafy vegetables. To avoid Cd-accumulation, besides monitoring soil Cd, it would be necessary to establish safe rates of fertilization for the cultivation of tropicalized lettuce varieties.