Descriptions of lead poisoning date to at least 2000 BC, while efforts to limit leads use date back to at least the 16th century. Concerns for low levels of exposure began in the 1970s with there being no safe threshold for lead exposure. Classification
Classically, "lead poisoning" or "lead intoxication" has been defined as exposure to high levels of lead typically associated with severe health effects. Poisoning is a pattern of symptoms that occur with toxic effects from mid to high levels of exposure; toxicity is a wider spectrum of effects, including subclinical ones (those that do not cause symptoms). However, professionals often use "lead poisoning" and "lead toxicity" interchangeably, and official sources do not always restrict the use of "lead poisoning" to refer only to symptomatic effects of lead.The amount of lead in the blood and tissues, as well as the time course of exposure, determine toxicity. Lead poisoning may be acute (from intense exposure of short duration) or chronic (from repeat low-level exposure over a prolonged period), but the latter is much more common. Diagnosis and treatment of lead exposure are based on blood lead level (the amount of lead in the blood), measured in micrograms of lead per deciliter of blood (μg/dL). Urine lead levels may be used as well, though less commonly. In cases of chronic exposure, lead often sequesters in the highest concentrations first in the bones, then in the kidneys.
Also, conservation programs exist which routinely capture condors, check their blood lead levels, and treat cases of poisoning. Notes
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