HEMODİYALİZ SÜRECİNDE MİKROPLASTİK VARLIĞININ VE MARUZİYET DÜZEYİNİN DEĞERLENDİRİLMESİ

Abstract

ABSTRACT Gümüşkemer İ.: Assessment of Microplastic Presence and Exposure Level During Hemodialysis; Hacettepe University Faculty of Medicine (HÜTF), Department of Internal Medicine Residency Thesis; Ankara, 2026. Objective: This study aims to simultaneously characterize the presence of microplastics across four sequential sampling points in a hemodialysis water purification chain, as well as in pre- and post-dialysis blood samples from the same patients, using five complementary analytical methods. Materials and Methods: This cross-sectional observational pilot study, conducted at Hacettepe University Faculty of Medicine Hospital in collaboration with Bilkent University UNAM, enrolled 6 hemodialysis patients. Water samples were collected at four points (municipal supply, post-purification, dialysis inlet, and dialysis outlet water) across three independent sessions; blood samples were obtained pre- and post-dialysis from each patient. Analytical evaluation comprised dynamic light scattering (DLS), scanning electron microscopy (SEM), Nile Red fluorescence microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR); the Friedman and Wilcoxon signed-rank tests were used for statistical assessment. Results: Dynamic light scattering analysis of the hemodialysis water purification chain revealed a consistent directional particulate pattern: a marked decrease following the purification stage and the highest values at the dialysis outlet. This pattern was reproduced without exception across all three sessions [Friedman χ²(3) = 8.200; p = 0.042; Kendall’s W = 0.911]; the mean hydrodynamic diameter increased ~208% and ~61% across two separate sampling sessions. SEM documented dominant fibrous morphology with accompanying fragmented and granular particles in all six patients; Nile Red fluorescence microscopy identified hydrophobic particulate structures in pre- and post-dialysis samples across all patients. Raman spectroscopy and FT-IR demonstrated independent convergence at ~1,100 cm⁻¹ in all water and blood samples; additional FT-IR bands (~2,848, ~2,915, ~2,960 cm⁻¹) matched the characteristic polyethylene (PE) infrared signature. FT-IR revealed vii consistent PE- and polyethylene terephthalate (PET)-compatible differential spectral patterns in pre- and post-dialysis isolates from all six patients. Blood DLS analysis yielded a pre-dialysis median of 1,292.76 d.nm [interquartile range: 1,123.40– 1,487.13] and a post-dialysis median of 1,078.87 d.nm [IQR: 910.23–1,304.00]. Intensity-based size distribution curves demonstrated that the small-particle population observed pre-dialysis was largely replaced by larger-sized components post-dialysis, a pattern consistent with membrane-derived particulate contribution and/or aggregation mechanisms. The Wilcoxon test did not reach statistical significance (W = 5.0; p = 0.313); however, a moderate effect size was observed (r = 0.471; Cohen’s d_z = 0.526), and post-hoc power analysis indicated that approximately 33 patients would be required for 80% statistical power. Conclusion: This first integrated pilot study to simultaneously examine the hemodialysis water purification chain and blood samples from the same patients using five analytical methods documented a particulate size increase at the dialysis outlet despite reverse osmosis purification, and a consistent PE/PET-compatible particulate burden in hemodialysis patient blood both before and after dialysis. These findings provide a systematic framework for updating hemodialysis biosafety standards to encompass plastic-derived contaminants, evaluating safer alternative polymer materials, and designing adequately powered, outcome-focused studies specific to this patient population.