How can lead stored in bones pose a risk to an individual?

Lead stored in bones can pose a significant risk to an individual because it has the potential to be released back into the bloodstream, especially during times of physiological stress such as illness, pregnancy, or during certain metabolic processes. When lead is mobilized from the bones, it can lead to increased levels of lead in the blood, which is detrimental to health and can cause lead poisoning or exacerbate existing health conditions.

The body mistakenly incorporates lead into the bone structure due to the similarities in chemical properties between lead and calcium. Over time, this stored lead can accumulate, creating a reservoir that might be tapped into when the body's needs change. This property of lead makes it particularly hazardous, as it allows for chronic exposure to toxic levels even when there are no ongoing external sources of lead exposure. Hence, the risk is not just from immediate exposure but also from the prolonged storage effects in bones that can re-enter the bloodstream and lead to systemic poisoning.