Fava bean intercropping with Sedum alfredii inoculated with endophytes enhances phytoremediation of cadmium and lead co-contaminated field.

Phytoremediation coupled with agro-production is considered a sustainable strategy for remediation of trace element contaminated fields without interrupting crop production. In this study hyperaccumulator Sedum alfredii was intercropped with a leguminous plant fava bean (Vicia fava) in cadmium (Cd) and lead (Pb) co-contaminated field to evaluate the effects of intercropping on growth performance and accumulations of trace elements in plants with plant growth promoting endophyte (PGPE) consortium application. The results showed, compared with monoculture, intercropping coupled with inoculation application promoted biomass as well as Cd and Pb concentrations in individual parts of both plants, thus increasing the removal efficiencies of trace elements (4.49-folds for Cd and 5.41-folds for Pb). Meanwhile, this superposition biofortification measure maintained normal yield and nutrient content, and limited the concentration of Cd and Pb within the permissible limit (<0.2 mg kg-1 FW) in fava bean during the grain production. These results demonstrated a feasible technical system for phytoremediation coupled with agro-production in slightly or moderately Cd and Pb co-contaminated field, and also provided useful information for further investigation of interaction mechanisms between intercropping and PGPEs inoculation.

Maize cultivars relieve health risks of Cd-Polluted Soils: In vitro Cd bioaccessibility and bioavailability.

Dietary grain ingestion is the primary route of human exposure to the adverse effects of Cd; therefore, an understanding of the transfer characteristics of Cd in a system involving soil, grain, and humans is crucial for health risk alleviation and pollution control. In this study, Cd bioaccessibility and bioavailability for humans from grains of sweet maize (Zea mays convar. saccharata var. rugosa) cultivars grown on a contaminated field (1.05 mg Cd kg-1 soil) were assessed by combining a simulated in vitro digestion method with a Caco-2 cell model. Results showed that cultivars differed significantly in grain Cd concentration, bioaccessibility, and bioavailability with the corresponding values of 0.07 to 0.20 mg kg-1 DW (dry weight), 4.10 to 6.20%, and 0.01 to 0.04 µg g-1grain, respectively. The estimated daily intake of Cd through sweet maize grain was within the range of 0.04 and 0.25 µg kg-1 body weight, which is lower than the tolerable limit recommended by the Joint FAO/WHO Expert Committee on Food Additives (JEFCA). Conclusively, results from the present study indicate that most grain Cd remains non-bioaccessible and thus might not present adverse health effects in humans. Therefore, sweet maize cultivars could be used to produce healthy food crops in low-to-moderately Cd-contaminated soil.