How do sardines compare to larger predator fish like tuna or swordfish regarding heavy metal accumulation?

They accumulate significantly less mercury because of their small size

A major advantage of consuming sardines is their low concentration of heavy metals, most notably mercury. This beneficial profile is directly attributed to their relatively small size and their position lower down on the aquatic food chain compared to larger, predatory fish such as tuna or swordfish. Because they consume smaller prey and are not apex predators, the process of biomagnification results in a far lower accumulation of toxins like mercury. Consequently, health authorities view sardines as a low-risk option for the general population, even for vulnerable groups like pregnant women, who can safely obtain valuable omega-3s without substantial mercury exposure.