Like the Romans used to drink from lead cups. Something like that.
(it appears that the moderator is removing any replies with which he disagrees. It might be a piefed issue. But all the removed replies are top level and upopular. Stranger coincidences have happened I suppose.)
About as much as is left over after the pasteurization and filtration the milk I drink goes through I guess. Is there a safe threshold that all commercial milk rests above?