Prediction of cadmium concentration in potato tubers "(Solanum tuberosum" L.) by pre-plant soil and irrigation water analyses

Potatoes grown in Australia have been identified as a major component of human dietary intake of cadmium (Cd). Potato growers must assess whether fields are high risk Cd environments. Combined soil and irrigation water analyses conducted before planting were studied as a way to predict the risks of Cd accumulation in tubers. Soil and water from 134 sites in Tasmania, Western Australia, South Australia, Victoria, and New South Wales were analyzed for electrical conductivity, major cations, anions, and cadmium. Irrigation water quality (conductivity or chloride concentration) explained more than 55% of the variation in tuber Cd concentrations. A probability curve of conductivity was developed for predicting tuber Cd exceeding the current maximum permitted concentration in Australia. Using these relationships, growers can quantify Cd risks simply by testing irrigation water conductivity before planting, and, if further precision is needed, analyzing extractable soil Cd.