Cadmium accumulation in potato tubers produced in Quebec

Abstract

Cadmium (Cd) is a heavy metal present in soils that can accumulate at relatively high levels in potato (Solanum tuberosum L.) with no negative effect on growth. Our objectives were to investigate Cd concentration in potato tubers produced in Quebec and to relate some soil characteristics, especially pH, P, and Cd, to tuber Cd concentration. Potato tubers (n = 75) and soil samples (n = 64) were collected from 1999 to 2006 at five experimental sites. Tuber Cd concentration ranged from 0.04 to 0.20 mg kg–1 dry matter (DM), with a median value of 0.11 mg kg–1 DM, and never exceeded the proposed tolerance for potato of 0.05 mg kg–1 fresh weight or about 0.25 mg kg–1 DM. Tuber Cd concentration was weakly, although not significantly, related to soil available P content (r2 = 0.53, P = 0.064), indicating a possible influence of soil P on Cd uptake by potato. Tuber Cd concentration was not directly related to soil pH, or to DTPA- or Mehlich 3-extractable Cd in soils. The log-transformed tuber Cd concentration was significantly (r2adj = 0.87, P < 0.01) related to both soil pH and VCd13, a generated variable that accounts for interactions between soil Cd and clay content, soil organic matter, and soil concentrations of Fe, Al, Mn, P, K, S, Ca, Cu, Zn, and B. Single factors such as soil Cd, soil P, or pH could not solely explain Cd accumulation in tubers; interactions between selected soil properties and soil Cd should be considered.Key words: Cadmium, phosphorus, Solanum tuberosum L., accumulation