First evidence of microplastic contamination in bottled herbal distillates: A quantitative and qualitative assessment of Iranian brands

• Study finds MPs in 92 % of Iranian herbal distillate samples. • Average contamination was 7.32 particles/L, primarily fibers and fragments. • Most particles were <500 μm and were transparent, white, or black in color. Herbal distillates, commonly consumed for their therapeutic and culinary properties, are often packaged in plastic containers which may lead to microplastics (MPs) contamination during production, transportation, and storage, although these sources of contamination are not definitive. The aim of this research is to assess the level of MPs contamination in these products and to identify the characteristics of the MPs present. A total of 50 samples from 10 popular Iranian herbal distillate brands were analyzed. The samples were filtered, and MPs were identified and quantified using a stereomicroscope, fluorescence microscope, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Results showed that 92 % of samples were contaminated with MPs, with an average concentration of 7.32 ± 9.24 particles/L. The most common types of MPs identified were fibers (62.30 %) and fragments (37.70 %). They are likely to consist mainly of polyethylene terephthalate (PET). Most MPs were smaller than 500 μm, and transparent (29.23 %), white (23.50 %), and black (16.12 %) colors were the most prevalent. The results of this study highlight the need for stricter quality control measures in the production and packaging processes of herbal distillates to reduce MPs contamination.