From sea to table: Assessing microplastic contamination in local and non-local salt in Bali, Indonesia

Microplastic contamination in table salt has emerged as a significant environmental and public health concern, particularly in regions like Bali, Indonesia, where salt is predominantly produced through seawater crystallization This study aimed to quantify and characterize microplastics in local and non-local table salts and estimate the potential microplastic intake. A total of 20 salt brands (10 local, 10 non-local) were collected and analyzed using density separation, stereomicroscopy, and FTIR spectroscopy. The results indicated that all salt samples contained microplastics, with an average concentration of 173 ± 119 particles/kg. Non-local salts exhibited higher contamination levels (211 ± 134 particles/kg) compared to local salts (135 ± 88 particles/kg). Fragments were the most prevalent microplastic type (55%), followed by fibers (44%), and smaller particles (≤500 μm) were the most common in size. A total of 13 polymer types were identified in the microplastic samples, with chlorobutyl (33%) and ethylene propylene rubber (29%) being the most dominant. Based on salt consumption rates, it was estimated that Bali residents ingest 1 microplastic particles per day, translating to an annual intake of 316-425 particles. These findings highlight the widespread nature of microplastic contamination in consumable salt and suggest potential health risks from the ingestion of microplastics, which may carry harmful pollutants. The study emphasizes the need for improved salt production practices, stricter pollution controls, and further research into the health implications of microplastic ingestion.