Digestive fluid components affect speciation and bioaccessibility and the subsequent exposure risk of soil chromium from stomach to intestinal phase in in-vitro gastrointestinal digestion

Quan Qian; Jun Liang; Zhefan Ren; Jingke Sima; Xiaoyun Xu; Jörg Rinklebe; Xinde Cao

doi:10.1016/j.jhazmat.2023.132882

Digestive fluid components affect speciation and bioaccessibility and the subsequent exposure risk of soil chromium from stomach to intestinal phase in in-vitro gastrointestinal digestion

J Hazard Mater. 2024 Feb 5:463:132882. doi: 10.1016/j.jhazmat.2023.132882. Epub 2023 Oct 29.

Authors

Quan Qian¹, Jun Liang¹, Zhefan Ren¹, Jingke Sima², Xiaoyun Xu¹, Jörg Rinklebe³, Xinde Cao⁴

Affiliations

¹ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
² State Environmental Protection Engineering Center for Urban Soil Contamination Control and Remediation, Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
³ School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, University of Wuppertal, Pauluskirchstraße 7, Wuppertal 42285, Germany.
⁴ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Shanghai Engineering Research Center for Solid Waste Treatment and Resource Recovery, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: xdcao@sjtu.edu.cn.

PMID: 37939559
DOI: 10.1016/j.jhazmat.2023.132882

Abstract

The simulated in-vitro gastrointestinal method provides a simple way to evaluate the health risk of human body exposed to soil contaminants. Several in-vitro methods have been successfully established for soil As, Pb, and Cd. However, the method development for soil Cr failed up to now, which could be resulted from alteration in the species of Cr (e.g., Cr(VI)/Cr(III)) caused by the gastrointestinal digestion components, ultimately affecting the accessibility of Cr. This study explored the transformation and bioaccessibility of Cr in two Cr-contaminated soils during the physiologically based extraction test. The water-soluble and exchangeable Cr in soil was dissolved in gastrointestinal tract, accompanied with reduction of Cr(VI) into Cr(III), and the reduction occurred after the chemical extraction in two soils rather than during the extraction. Pepsin and organic acids in gastric phase could reduce Cr(VI) into Cr(III) and reduction efficiency were 20.4%- 53.0%, while in intestinal phase, pancreatin and bile salt had little effect on the Cr(VI) reduction, instead, more Cr(VI) was released from soil. In the gastric solution, Cr(VI) was mainly present as HCrO₄^- and Cr(III) as free Cr³⁺ ion. In the intestinal phase, Cr(VI) mainly occurred as CrO₄^2- and Cr(III) as Cr(OH)₃ (aq). Cr in the soil solid phase was dominated as the precipitates of Cr-Fe oxide, which was hardly extracted. Bioaccessibility of Cr in gastric phase increased as extraction duration increased and decreased in the intestinal phase, the contrary trend was observed for the hazard quotient of Cr in two phases due to Cr(VI)/Cr(III) transformation. This study indicates that the gastrointestinal components could influence the Cr transformation and subsequently affect the Cr bioaccessibility, which would help for a successful establishment of in vitro determination method for soil Cr bioaccessibility.

Keywords: Bioaccessibility; Digestive components; Health risk; Soil Cr(VI); Transformation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Chromium / analysis
Chromium / toxicity
Digestion
Humans
Soil Pollutants* / analysis
Soil*
Stomach / chemistry

Substances

chromium hexavalent ion
Soil
Chromium
Soil Pollutants