Analysis of the effect of salt processing on microplastic residues in crushed and washed sea salt

This study focused on issues related to sea salt processing caused by marine microplastic pollution and investigated the effect of crushed and washed sea salt (CWSS) processing on microplastics (MPs) residues for the first time. Thirteen MPs contaminants were identified in the crude salts derived from seawater crystallization, with relative abundance of 256 ± 26 particles/10 g detected. After CWSS processing there were a total of 6 ± 5–112 ± 30 particles/10 g abundance in the final product. The results confirmed that the CWSS process had a significant impact on the abundance distribution of MPs in sea salt (p-value = 0.00147 0.05). •Reported the effects of the CWSS processing on microplastics for the first time.•The CWSS consisted of 19 MPs types and their additives.•The CWSS process significantly removed MPs from the crude salt.•MPs-introduced critical step: flexible freight bags package & laser color selection.