Human health risks of chromium in bright-colored leather products: Speciation-based insights into dermal permeation

Abstract

Chromium (Cr) is a highly-toxic carcinogenic metal, which exists as chromite (CrIII) and chromate (CrVI) in the enviornment, with CrVI being used in leather production. With the increasing demand for leather products, health risks associated with Cr exposure of leather products from dermal contact require scrutiny. In this study, 105 leather samples were analyzed for total Cr, Cr speciation, and bioaccessible Cr. Further, 5 samples with the highest bioaccessible Cr were assessed for permeable Cr through mouse skin using Franz diffusion cells. Total Cr and CrVI contents were high in all samples, with total Cr being 32−45,800 mg kg⁻¹ and CrVI being 0.5–64.3 mg kg⁻¹. Notably, 82% of samples exceeded the European regulatory limit of 3 mg CrVI kg⁻¹ for leather products. Based on a dermal in-vitro assay, bioaccessible Cr contents were high and varied with leather color from 260 to 3,990 mg kg⁻¹ and were positively correlated with the CrVI contents. Specifically, leather samples with brighter color had greater bioaccessible Cr and total CrVI contents. Moreover, data from 24-h permeation tests indicate a positive correlation between permeable Cr and CrVI concentration in simulated sweat solution, which were utilized to refine exposure for human health risk assessment. Long-term dermal exposure to Cr in leather products may pose both permeable-Cr induced non-carcinogenic and permeable-CrVI induced carcinogenic risk for adults and children. This study suggests that bright-colored leather products may pose carcinogenic risk via dermal contact, emphasizing the need for increased attention to potential Cr exposure from leather products.