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Lead-211, −212, and −214 are present in the decay chains of uranium-235, thorium-232, and uranium-238, respectively, so traces of all three of these lead isotopes are found naturally. Minute traces of lead-209 arise from the very rare cluster decay of radium-223, one of the daughter products of natural uranium-235, the rare beta-minus ...
Measuring a person's blood lead level requires a blood sample, which may be performed with a fingerstick or a blood draw. The amount of lead found in the blood sample may be measured in micrograms of lead per deciliter of blood (μg/dL) especially in the United States; 5 μg/dL is equivalent to 0.24 μmol/L . [6]
Cases of mass lead poisoning can occur. In 2009, 15,000 people were planned to be relocated from Jiyuan in central Henan province to other locations after 1000 children living around China's largest smelter plant (owned and operated by Yuguang Gold and Lead) were found to have excess lead in their blood. The total cost of this project is ...
The World Health Organization (WHO) specifically notes that there is "no known safe blood lead concentration," and that even blood lead concentrations as low as 3.5 µg/dL (micrograms per ...
The major source of lead exposure during the 20th century was leaded gasoline. Proponents of the lead–crime hypothesis argue that the removal of lead additives from motor fuel, and the consequent decline in children's lead exposure, explains the fall in crime rates in the United States beginning in the 1990s. [4]
The venous system returns the de-oxygenated blood to the right heart where it is pumped into the lungs to become oxygenated and CO 2 and other gaseous wastes exchanged and expelled during breathing. Blood then returns to the left side of the heart where it begins the process again.
Galena is the main ore of lead, used since ancient times, [6] since lead can be smelted from galena in an ordinary wood fire. [7] Galena typically is found in hydrothermal veins in association with sphalerite, marcasite, chalcopyrite, cerussite, anglesite, dolomite, calcite, quartz, barite, and fluorite.
Blood accounts for 7% of the human body weight, [9] [10] with an average density around 1060 kg/m 3, very close to pure water's density of 1000 kg/m 3. [11] The average adult has a blood volume of roughly 5 litres (11 US pt) or 1.3 gallons, [ 10 ] which is composed of plasma and formed elements .