For those curious about the measurements and methodologies:
A wide range of MP [microplastics] content (in number of MPs per kg of salt; n/kg) was found: 0–1674 n/kg (excluding one outlier of 13 629 n/kg) in sea salts, 0–148 n/kg in rock salt, and 28–462 n/kg in lake salt.
and
A total of 39 brands of commercial table salt were collected from the supermarkets of 17 different countries on four continents…. The analysis of MPs in salts [procedure was that], a 250 g unit sample was digested and dissolved using 17.25% H2O2 solution and filtered through a filter (GF/D; ø 2.7 μm; Whatman), and all of the MP-like particles on the filter were analyzed using microscopic and spectroscopic analysis.
