Effect of humic acid amendment on cadmium bioavailability and accumulation by pak choi (Brassica rapa ssp. chinensis L.) to alleviate dietary toxicity risk

ABSTRACT

Cadmium (Cd) contamination in soil and its movement into food chain through vegetable dietary poses a risk to human health. A pot experiment was conducted to investigate the effect of humic acid (HA) and two cultivars of Brassica rapa ssp. chinensis L. (pak choi) with differing Cd accumulation abilities on Cd accumulation in different Cd contaminated Ferralsol, Histosol and Luvisol soils. The results showed that HA significantly increased soil pH and cation exchange capacity in Ferralsol (acidic) and Histosol (neutral) soils. HA was more effective in Ferralsol and Histosol soil in reducing bioavailable Cd and its accumulation in both cultivars. Low and high Cd accumulating cultivars combined with HA effectively reduced shoot Cd concentration by 7–34% and 19–35% in Histosol soil, whereas 22–34% and 11–26% in Ferralsol soil, respectively. However, no such reduction was observed for Cd accumulation and bioavailability in Cd-contaminated Luvisol (alkaline) soil. Application of HA enhanced shoot dry biomass in both cultivars grown in Histosol and Ferralsol soils. Therefore, the HA amendment combination with low Cd accumulating cultivars of pak choi could be an effective method for phytostabilization and reduce health risks associated with consuming this vegetable grown in Cd-contaminated acidic and neutral pH soils.

KEYWORDS:

• Pak choi
• humic acid
• health risk
• soils

Acknowledgments

This work was financially supported by a grant from the Ministry of Science and Technology of China (Grant no. 2012AA100405) and from University innovative research funds (Grant no. 2015FZA6008). K. Y. Khan acknowledges China Scholarship Council for providing a PhD scholarship under China Government Scholarship Programme.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by a grant from the Chinese Ministry of Science and Technology (Grant no. 2012AA100405) and from Zhejiang University innovative funds (Grant no. 2015FZA6008).