Microplastics footprint in Indonesian edible salt: A comparative study across Western, Central, and Eastern regions.

Abstract

Microplastics contamination in food products has raised global concerns, yet nationwide assessments in edible salt (particularly in Indonesia) remain limited. Most prior studies have focused on isolated locations, offering an incomplete understanding of spatial distribution and exposure risk. This study aims to analysis of microplastics abundance, charcateristic, and potential human intake in edible salt samples across Western, Central, and Eastern Indonesia. A total of 45 salt brands (three replicates per brand) were selected based on regional consumer preferences. Microplastics were extracted using a density separation technique, followed by visual screening and polymer identification. The mean microplastics abundance was 221.9 ± 184.0 particles/kg. Microplastics abundance was highest in Western Indonesia (292.0 ± 254.2 particles/kg), followed by Central Indonesia (212.9 ± 131.4 particles/kg) and Eastern Indonesia (160.9 ± 111.1 particles/kg). Overall, fibers (79.44%) and fragments (19.29%) were the dominant microplastics shapes. Fibers predominated across all regions, particularly in Western (85.54%), Central (67.01%), and Eastern Indonesia (84.81%). Small-sized microplastics (<1,000 μm) were most prevalent overall (59.41%). Regionally, small-sized particles dominated in Western (61.80%) and Central Indonesia (63.67%), whereas larger microplastics (>1,000 μm) were more common in Eastern Indonesia (50.55%). Fifteen polymer types were identified, with chlorobutyl (21.15%), polyester fiber (19.87%), and polyisobutylene (19.35%) most prevalent overall. However, polyester fiber (41.51%), ethylene propylene (42.50%), and polyisobutylene (47.62%) dominated in Western, Central, and Eastern Indonesia, respectively. Estimated Daily Intake ranged from 1.11 ± 0.71 to 1.56 ± 0.99 particles/day, depending on region and consumption level, while the corresponding