It is reported that an alarming percentage of ancient Romans suffered from mental disorders due to the use of lead pipes for bringing water into the homes from the city aqueduct system. Perhaps this even helps explain what happened to some of the depraved Roman emperors such as Caligula, whose insanity is theorized to be of organic origin. Lead poisoning can be either acute or chronic. The acute form is caused by sudden exposure to large doses of lead by ingesting it in large amounts. Eating tiny particles of lead also increases exposure because more surface area allows for greater stomach acid exposure.
Small particles sit in the gizzard for a long time.
Bullets are routinely left in soldiers when the lead projectile is not in a life- threatening location. The onset of clinical signs is rapid in acute lead poisoning. Chronic lead poisoning is much more gradual, caused by environmental exposure to small amounts of lead over a long period of time. Because of the insidious nature of chronic exposure, clinical signs are much less obvious and diagnosis can be much more difficult. The clinical signs of lead poisoning are varied between cases, depending on the amount the bird is exposed to, what period of time the exposure took place in, and what species the bird belongs to as well as its age and body weight.