Heavy metal and Microplastic exposure from sports protein Supplements: Integrated health risk modeling and scenario...

This study presents an integrated co-exposure assessment of toxic metals and microplastics in 30 commercially available sports protein supplements in China by combining targeted analytical measurements with scenario-based and probabilistic health-risk modeling. Arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) were quantified via closed-vessel microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS), validated through duplicate analyses and reference materials. While all samples contained at least one target metal, plant-derived products exhibited higher mean Pb (0.18 mg/kg) and Cd (0.05 mg/kg) levels compared to dairy-derived products (0.06 and 0.01 mg/kg, respectively; P < 0.01). Notably, a brown rice and cocoa-flavored product emerged as an outlier (Pb 0.60 mg/kg; Cd 0.15 mg/kg; As 0.30 mg/kg), whereas Hg concentrations were predominantly <0.01 mg/kg, except for one collagen sample (0.02 mg/kg). Microplastic particles were isolated via peroxide-alkali digestion and identified by micro-Fourier transform infrared (μFTIR) and micro-Raman spectroscopy (μRaman). Microplastics were detected in all samples, ranging from 2 to 19 particles per 30 g serving (mean 8 ± 5); these were predominantly comprised of fibers (40-50%) and fragments (∼30%), with typical sizes of 100-500 μm and polymers including polyethylene, polypropylene, and polyethylene terephthalate. ∗∗ regarding exposure risks∗∗, deterministic modeling yielded a hazard index (HI) of 0.45 for 30 g/day and 0.90 for 90 g/day (driven primarily by As and Cd), while Monte Carlo simulation (10,000 iterations) indicated a 95th-percentile HI of 1.28 under high-use conditions; predicted blood Pb increments remained <3 μg/dL. Collectively, these results offer a quantitative basis for prioritizing contaminant control in high-consumption scenarios and for informing athletes, manufacturers, and regulators about combined contaminant burdens. These findings align with emerging evidence of ubiquitous microplastic presence in protein products and underscore the necessity for consumption-scenario-based risk evaluation regarding heavy metals.