Oxidation States of Toxic Metals in Food Toxicology: A Critical Gap

Food Sciences | Letter to Editor | https://doi.org/10.47262/SL/13.2.132025230

Zafar Ali 1,2*, Farah Naz Talpur 2, Nazir Ahmad Brohi 3, Habibullah Abbasi 4

1 National Centre of Excellence in Analytical Chemistry, University of Sindh, 76080, Jamshoro, Sindh, Pakistan

2 Chemistry Department, University of Turbat, 92600, Balochistan, Pakistan

3 Department of Microbiology, University of Sindh, 76080, Jamshoro, Sindh, Pakistan

4 Center for Environmental Sciences, University of Sindh, 76080, Jamshoro, Sindh, Pakistan

Abstract

Toxic metals such as chromium (Cr), nickel (Ni), arsenic (As), mercury (Hg), cadmium (Cd), and lead (Pb) are frequently detected in food and are known for their significant health hazards. However, many studies focus solely on total metal concentrations, often neglecting the critical influence of oxidation states on toxicity, mobility, and bioavailability. For example, chromium in the higher oxidation state (Cr6+) and arsenic in the lower oxidation state (As³+) are remarkably more toxic than their respective lower (Cr³+) and higher (As5+) oxidation states, while methylmercury (CH3Hg+) poses far greater health risks than elemental mercury. Overlooking these differences can lead to inaccurate health risk assessments. This letter emphasizes the necessity of identifying both concentrations and oxidation states to support a more precise evaluation of food safety. Although advanced spectroscopic techniques such as X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICP-MS) can provide this insight, their complexity and cost hinder widespread adoption. Addressing this research gap through collaborative, cost-effective strategies and standardized methodologies can substantially improve the accuracy of food toxicology assessments and safeguard public health.