You are right about the risk of heavy metal contamination so wont comment on that. But if we are speaking about an animal that crapped on top of the clay pile then that should not be an issue. Soil in general but especially clay has an absolutely enormous surface area that adsorbs both bacteria and viruses. That’s why ground water is usually safe to drink but surface water is not. A large amount of faeces leaking into the soil water from above would potentially contaminate the water with nitrate which could be a slight cancer risk if consumed in large quantities but there should be no risk of getting infected if you are digging deep unexposed clay, even if an animal crapped on top of the pile. As long as there is no heavy metal contamination eating deep clay is probably safer than eating a wild picked berry.
You are right about the risk of heavy metal contamination so wont comment on that. But if we are speaking about an animal that crapped on top of the clay pile then that should not be an issue. Soil in general but especially clay has an absolutely enormous surface area that adsorbs both bacteria and viruses. That’s why ground water is usually safe to drink but surface water is not. A large amount of faeces leaking into the soil water from above would potentially contaminate the water with nitrate which could be a slight cancer risk if consumed in large quantities but there should be no risk of getting infected if you are digging deep unexposed clay, even if an animal crapped on top of the pile. As long as there is no heavy metal contamination eating deep clay is probably safer than eating a wild picked berry.