Plastic in Your Pop: Spectroscopy Reveals Microplastics in Iran’s Popular Soft Drinks

Plastic in your pop: spectroscopy reveals microplastics in Iran’s popular soft drinks © Your Hand Please -chronicles-stock.adobe.com

Plastic in Every Sip: Study Finds Microplastics in Iranian Soft Drinks

A recent peer-reviewed study has revealed that microplastics are present in every tested sample of soft drinks and non-alcoholic beverages marketed in Iran. The research, published in Results in Engineering, identifies polyethylene terephthalate (PET)—commonly used in beverage containers—as the primary contaminant, using Raman spectroscopy to determine the particles’ chemical composition and morphology (1).

The study was conducted by researchers Elnaz Hoseinzadeh, Hamed Hossini, Parinaz Makhdoumi, Shima Parsa, and Tayebeh Massahi. Their affiliations include academic and environmental health research institutions in Iran, though specific university affiliations were not listed in the publication summary (1).

Scope and Methods

The researchers purchased 50 samples of popular soft drinks and non-alcoholic beverages from different brands and vendors across Iranian markets. The analysis focused on determining the number, size, shape, and polymer type of microplastic particles present in each beverage.

Each sample underwent filtration and visual analysis under a stereomicroscope. To confirm the chemical identity of the particles, Raman spectroscopy was used. This highly sensitive vibrational spectroscopic method allowed the researchers to precisely identify polymer types based on their molecular fingerprint (1).

Microplastic Concentration and Composition

The study found that 100% of the tested samples contained microplastics, with concentrations ranging from 9.12 to 31.94 particles per liter, and an average of 19.9 particles per liter.

Most microplastic particles were fibers (76%), followed by fragments (22%) and films (2%). Particle sizes ranged from 9 µm to 283 µm, with 68% of all particles measuring below 50 µm—small enough to be consumed and absorbed into the human body (1).

Raman Spectroscopy Findings

Raman spectroscopy revealed that the most common polymer in the samples was polyethylene terephthalate (PET)—the material used for plastic beverage bottles. Other polymers identified included polypropylene (PP), polystyrene (PS), and polyethylene (PE) (1,2).

The detailed molecular data from Raman spectroscopy helped the researchers not only confirm the presence of microplastics but also trace potential sources, suggesting that PET containers and bottling processes are key contributors to this contamination (1,2).

Color and Shape of Particles

The visual analysis revealed the dominant colors of microplastic particles were blue (39%), transparent (24%), and black (21%), with red, yellow, and green particles making up the remainder. The prevalence of blue and transparent microplastics suggests contact with bottle materials, caps, or environmental contamination during production (1).

Likely Sources and Health Implications

The authors suggest that poor manufacturing standards, abrasion during bottling, and contact between the beverage and its container are probable sources of microplastic contamination. While the study did not explore health outcomes directly, the presence of microplastics in consumable liquids is an ongoing concern in food safety and public health research (1).

The research aligns with a growing body of global evidence indicating microplastics are not only present in ocean water and seafood but also in drinking water, salt, and now widely consumed soft drinks.

References

(1) Hoseinzadeh, E.; Hossini, H.; Makhdoumi, P.; Parsa, S.; Massahi, T. Microplastics Contamination in Popular Soft Drinks and Non-Alcoholic Beverages Marketed in Iran: Quantity and Characteristics. Results Eng. 2024, 24, 103158. DOI: 10.1016/j.rineng.2024.103158

(2) Aloia, R.; Annunziata, L.; Di Giacinto, F.; De Simone, S.; Profico, C.; Fanelli, I.; Di Francesco, G.; Mussi, V.; Scortichini, G. Application of Raman Spectroscopy for the Analysis of Microplastics in Food and Beverages: A Comprehensive Review. Appl. Spectrosc. Rev. 2025, in press, 1–35. DOI: 10.1080/05704928.2025.2512771