Answered
Nostoc is generally not harmful to humans in the sense that it is not toxic or infectious. However, it can cause skin irritation if there is prolonged contact with the mucilaginous surface of the mats, particularly in individuals with sensitive skin. In rare cases, nostoc can produce toxins (like microcystins) that may lead to more severe reactions, though these toxins are primarily a concern for aquatic environments. If nostoc is ingested, it may cause gastrointestinal distress, but such occurrences are extremely rare in the context of gravel driveways. Allergic reactions, including respiratory issues, can also occur in some individuals when they inhale the airborne spores or particles. For safety, it’s advisable to wear gloves and protective clothing when handling nostoc mats and avoid prolonged exposure to them.
BNO Team