Predicting plant uptake of cadmium: validated with long-term contaminated soils

Abstract

Cadmium accumulates in plant tissues at low soil loadings and is a concern for human health. Yet at higher levels it is also of concern for ecological receptors. We determined Cd partitioning constants for 41 soils to examine the role of soil properties controlling Cd partitioning and plant uptake. From a series of sorption and dose response studies, transfer functions were developed for predicting Cd uptake in Cucumis sativa L. (cucumber). The parameter log K was predicted with soil pH, logCEC and log OC. Transfer of soil pore-water Cd to shoots was described with a power function (R = 0.73). The dataset was validated with 13 long-term contaminated soils (plus 2 control soils) ranging in Cd concentration from 0.2 to 300 mg kg. The series of equations predicting Cd from pore-water Cd were able to predict the measured data in the independent dataset (root mean square error = 2.2). The good relationship indicated that Cd uptake to cucumber shoots could be predicted with Cd and Cd without other pore-water parameters such as pH or Ca. The approach may be adapted to a range of plant species.

Cadmium and Lead Exposure, Nephrotoxicity, and Mortality

“…Like all other metals, Cd and Pb are not biodegradable and thus can persist indefinitely in the environment [55]. The use of contaminated phosphate fertilizers has also added these toxic metals to agricultural soils [6,7], causing a further increase in Cd and Pb in the food chain [66][67][68]. Livestock that graze on contaminated pastures can accumulate Cd in the kidney and liver at levels that make these organs unsafe for human consumption [69].…”

Cadmium Toxicity: Oxidative Stress, Inflammation and Tissue Injury

“…A contributing factor to its circulation in the environmental compartments is its high persistence due to non-biodegradability. Additionally, the metal is reported to have a high rate of transfer from soil-to-plant, making it possible for Cd to enter the food chain [2].…”

Cadmium, silicon and nutrient accumulation by maize plants grown on a contaminated soil amended with a diatomaceous Earth fertilizer

“…The entry of Cd into the food chain is facilitated by the metal high mobility in both soils and plants, which, in turn, reduces the uptake of nutrients and water, inhibits photosynthesis and alters the expression of genes and proteins. Since food consumption is the main route of human exposure to contaminants, high Cd mobility is a threat to food safety (LAMB et al, 2016). Therefore, strategies that aim to decrease the mobility and consequent transfer of Cd from soil to plants are essential to reduce the risk of Cd food chain contamination.…”