# Influence of Foliar Zinc Application on Cadmium and Zinc Bioaccessibility in Brassica chinensis L.: In Vitro Digestion and Chemical Sequential Extraction

## TL;DR

This study shows how applying zinc to pakchoi plants affects how much cadmium and zinc can be absorbed by the human body, influencing health risks.

## Contribution

The study reveals how foliar zinc application modulates cadmium and zinc bioaccessibility in pakchoi through specific chemical forms.

## Key findings

- Spraying ZnSO4 reduced bioaccessible cadmium and health risks, while high-dose ZnNa2EDTA increased them.
- Foliar Zn application significantly increased bioaccessible zinc concentrations in pakchoi.
- Ethanol- and water-extractable forms contributed over 59% of bioaccessible cadmium and zinc.

## Abstract

Foliar zinc (Zn) application can affect the accumulation and bioaccessibility of cadmium (Cd) and Zn in crops. However, the mechanisms by which foliar Zn application influences Cd and Zn bioaccessibility remain elusive. This study examined the effects of spraying ZnSO4 and ZnNa2EDTA on bioaccessibility and chemical forms of Cd and Zn in pakchoi (Brassica chinensis L.) shoots and evaluated human health risks via pakchoi consumption. Spraying ZnSO4 reduced the concentrations of ethanol-extractable (Fethanol) and deionized water-extractable (Fd-H2O) Cd, as well as the corresponding bioaccessible Cd concentrations (20.3–66.4%) and attendant health risks of Cd, whereas spraying high-dose ZnNa2EDTA significantly increased the concentrations of both Cd forms and bioaccessible Cd. Spraying ZnSO4 and high-dose ZnNa2EDTA significantly increased the concentrations of Zn in Fethanol and Fd-H2O and the corresponding bioaccessible Zn concentrations (0.8–8.3-fold). Fethanol and Fd-H2O were the primary sources of bioaccessible Cd and Zn, contributing more than 59% of the bioaccessible Cd and Zn. These results indicate that foliar Zn application can affect Cd and Zn bioaccessibility in pakchoi mainly by modulating Cd and Zn in Fethanol and Fd-H2O. These findings provide scientific support for the development of more efficient measures to produce safe and high-quality leafy vegetables from Cd-polluted soils.