Running dirty seawater through sand might catch most of the tiny plastic bits, so the salt we make from it could end up cleaner.

What we've found so far suggests that sand filtration may help reduce microplastic contamination in sea salt production. Our analysis of the available evidence shows support for the idea that filtering seawater through sand can capture many of the tiny plastic particles present in the water [1]. We looked at one key assertion, which states that running dirty seawater through sand could remove most microplastics, leading to cleaner sea salt [1]. This idea is supported by 26.0 studies or data points, with no studies found that refute it. While we don’t have direct details on the methods or settings of these supporting sources, the consistent support across them suggests the evidence we've reviewed leans toward sand filtration being a potentially effective step in reducing microplastic levels during salt production. Still, our current analysis is based on limited assertions—just one distinct claim so far—even if it’s backed by multiple supporting points. We don’t yet know how much microplastic is removed in real-world conditions, what sizes of particles are caught, or how this method compares to other filtration techniques. Also, we haven’t reviewed evidence on whether the cleaned salt actually shows lower microplastic content after processing. Because this is what we've found so far, we can’t say for sure how well it works across different environments or salt-making operations. More evidence could change how we understand this over time. Practical takeaway: Filtering seawater through sand might help make sea salt with fewer microplastics, but we don’t yet know all the details of how well or consistently it works.