Establishment of a Model to Assess Soil Cadmium Uptake by Brassica Chinensis

Abstract

Core Ideas Cadmium uptake by Brassica chinensis was positively related with soil Cd content. Soil pH and OC acted as dominant factors regulating Cd uptake in Brassica chinensis. The log‐transformed data was more appropriate in establishing the regress equations. The predication model was best established combining with soil pH and OC. Estimating cadmium (Cd) bioavailability and transfer to plants are important for food safety. We aimed to determine the dominant soil factors regulating the transfer of Cd from a wide variety of Chinese soils to Pak Choi (Brassica chinensis) and to establish a model for prediction of Cd uptake in B. chinensis. A greenhouse experiment was conducted in which B. chinensis plants were grown under 14‐h 20°C light/10‐h 16°C dark photoperiod for 60 d. The total Cd content in the plant and soil samples was measured. The Cd concentration in B. chinensis was positively correlated to the soil Cd concentration, and negatively correlated to the soil pH and soil organic carbon (SOC) content. The bio‐concentration factors (BCF) measured in acidic soils (the maximum value being 0.551) were higher than those in alkaline soils (the maximum value being 0.366). Multivariable (pH, SOC, and total soil Cd) regression analysis could estimate the Cd bioavailability more accurately compared with the single‐factor (total soil Cd) analysis. The most accurate Freundlich‐type equation (Log[Cplant] = 2.34Log[Csoil] – 0.27pH – 0.23Log[SOC] + 0.92) was developed to estimate the Cd bioavailability using combined data from all treatments. The model described by us would be useful for estimating the bioavailability of Cd to B. chinensis in a variety of soils and would be helpful in assessing the risk of Cd contamination in soils.