PFAS aka. "forever chemicals" can be found almost everywhere, including the human food chain. They are associated with adverse health outcomes, such as decreased birth weight, kidney diseaese, and cancer. Scientists have now demonstrated that some bacterial strains of the human gut microbiome (e.g. Bacteroides) are able to filter PFAS and accumulate them up to 50-fold. This increases the excretion of the forever chemicals in feces. Another reason to treat your microbiome well. Bacteroides mainly live from fiber.