Accumulation of Cd in Different Crops and Screening of Low-Cd Accumulation Cultivars

Abstract

Pot-culture experiments were carried out in Shanghai to screen crop varieties with low bioaccumulation properties with respect to cadmium (Cd). Eight common crops, such as green pepper, cucumber, cowpea, spinach, cauliflower, tomatoes, rice, and wheat, were planted in contaminated soil with different Cd concentrations of 0.23, 0.6, 1.2, 1.8, 2.4, and 3.0 mg·kg-1 to investigate the effects on biomass, Cd accumulation characteristics, and edible risk safety. The results indicated that:① With the increase in soil Cd content, the aboveground biomass of crops increased firstly and then decreased. The different crop types had different tolerance to Cd, with green pepper showed the strongest tolerance and spinach and tomato showed the least tolerance. ② The bioaccumulation factor of Cd in the edible parts of eight crops ranged in order of wheat > spinach > rice > green pepper > cauliflower > tomato > cucumber > cowpea. ③ Total Cd content in soil was significantly correlated with Cd content in the crops (P<0.05), and the order of the correlation coefficients was spinach > wheat > tomato > cucumber > green pepper > rice > cauliflower > cowpea. ④ The risk threshold value of Cd in soil based on the edible safety of different crops ranged in order of cowpea > cucumber > cauliflower > green pepper > tomato > rice > spinach > wheat. Cucumber, cowpea, and cauliflower were selected as the low-Cd-accumulating varieties according to their tolerance to soil Cd, bioaccumulation capacity, and edible risk threshold values.