During what blood levels does lead start to cause cognitive impairment in adults?

A-hi10ug/dl,C-5ug/dl: Elevated lead in the body can be detected by the presence of changes in blood cells visible with a microscope and dense lines in the bones of children on X-ray, main tool for dx. is the blood lead level. When blood lead levels are recorded, the results indicate lead is circulating within the blood stream, not the amt. being stored in the body.[2] Elevated lead in the body can be detected by the presence of changes in blood cells visible with a microscope and dense lines in the bones of children seen on X-ray, but the main tool for diagnosis is measurement of the blood lead level. When blood lead levels are recorded, the results indicate how much lead is circulating within the blood stream, not the amount being stored in the body.[2] There are two units for reporting blood lead level, either micrograms per deciliter (µg/dl), or micrograms per 100 grams (µg/100 g) of whole blood, which are numerically equivalent. The Centers for Disease Control (US) has set the standard elevated blood lead level for adults to be 10 (µg/dl) of the whole blood. For children the number is set much lower at 5 (µg/dl) of blood as of 2012[3] down from a previous 10 (µg/dl).[4] Children are especially prone to the health effects of lead and, as a result, blood lead levels must be set lower and closely monitored if contamination is possible.[2] The major treatments are removal of the source of lead and chelation therapy (administration of agents that bind lead so it can be excreted).