0
Article ? AI-assigned paper type based on the abstract. Classification may not be perfect — flag errors using the feedback button. Tier 2 ? Original research — experimental, observational, or case-control study. Direct primary evidence. Sign in to save

Coconut shell-based salt pot, “Lunu Polkatta,” in mitigating microplastic contamination in food-grade granular crystal salt

Ceylon Journal of Science 2026
R. M. Pabasara Abeywickrama, B. A. P. Chamini Premathilake, Rupika S. Rajakaruna

Summary

Researchers found that storing salt in a traditional Sri Lankan coconut shell pot (called a "lunu polkatta") significantly reduced the amount of microplastics in the salt compared to salt stored in glass containers. This suggests a simple, low-cost, plastic-free storage method could help cut down on the tiny plastic particles we unknowingly eat through salt every day. While more research is needed to confirm how this works and whether it applies broadly, it's a promising, culturally-rooted solution to a growing food safety concern.

Microplastic (MP) contamination of food-grade salt represents an increasing food safety concern, yet practical household-level mitigation strategies are limited. This study evaluated the effectiveness of the traditional Sri Lankan coconut shell-based salt pot (lunu polkatta) in reducing MP contamination in food-grade, iodized, granular crystal salt during storage. Salt solutions were stored in two independent coconut shell-based salt pots for three months under plastic-free conditions, with parallel glass-container controls. MPs were extracted using membrane filtration (0.45 µm), quantified by a dissecting microscope, and selected particles were identified using ATR-FTIR spectroscopy. One-way ANOVA revealed a significant difference in MP counts among the initial salt solution, salt retained inside the shells, and salt accumulated on the outer layers (F = 82.33, p < 0.001). Post hoc analysis indicated significantly lower MP counts inside the shells compared to both the initial salt solution and the outer salt layers, and MP counts in the outer layers also differed significantly from those in the initial salt solution. No significant changes were observed in the control samples stored in glass containers over three months (t = −0.024, p = 0.981). These findings demonstrate that lunu polkatta consistently reduced MP abundance within stored salt through passive, shell-mediated processes, offering a reproducible, low-cost, and culturally integrated approach for mitigating dietary MP exposure.

Share this paper