At blood lead levels above 900 ug/L (90 ug/dl), poisoning can cause acute lead encephalopathy. Peripheral neuropathy results from levels above 600 ug/L (60 ug/dl). Most reports of lead-related symptoms (fatigue, abdominal pain, and arthralgia) begin at blood levels greater than 600 ug/L. Typical concentrations of lead in surface water in the USA is between 5 and 30 ug/L. Typical intake of lead in the USA is 2 to 9 ug per day from food, water, and beverages. "In an analysis of PbB and neurobehavioral test results from 40,000 participants from NHANES III, no statistically significant relationships between blood lead concentration and neurobehavioral test performance were found. . . . Tibia lead, representative of cortical bone, has a residence time of 25 to 30 years and serves as a biomarker of cumulative dose. . . . With additional study, lead in bone could be a viable measure of lead body burden, but at this point in time, the database is insufficient." [ACGIH: BEI Documentation] Heavy lead exposure causes anemia; Lead inhibits hemoglobin synthesis (ALAD and other enzymes), and also shortens lifespan of RBCs with resulting hemolysis. [Nordberg, p. 939-40] Exposure to high air concentrations of lead can precipitate hemolytic anemia. "The anemia of chronic lead toxicity, the primary hematologic effect of lead exposures, is enhanced by shortened red cell survival as well as by inhibition of hemoglobin synthesis." [LaDou, p. 265] At blood levels above 50-60 ug/dl, suppression of heme synthesis causes anemia. [Rom, p. 978] Lead-exposed workers may develop proximal renal tubular damage and progressive renal insufficiency. [Rom, p. 966] Lead can produce slight hepatic injury in experimental animals. [Zimmerman, p. 419] There is strong positive data associating lead exposure with spontaneous abortions and prematurity in pregnant women, neurological dysfunction in children and decreased sperm counts in men. [ATSDR Case Studies #29] The OSHA standard requires periodic determination of blood lead in workers exposed at or above action level (30 ug/m3) for more than 30 days per year. [ATSDR ToxProfiles] About 90% of pre-1940 homes contain lead-based paints, while about 60% of 1960-1979 homes contain significant amounts of lead in paint. The use of lead piping and lead solder in plumbing has been prohibited since 1986. [Coluccio VM. Lead-Based Paint Hazards. Wiley, John & Sons; 1997, p. 8-15] Inorganic lead compounds are probable human carcinogens. Organic lead compounds are not classifiable. [IARC] In contrast to inorganic lead, organic compounds are absorbed readily through the skin and into the CNS. [Sullivan, p. 979] Trabecular lead (measured in the patella) reflects exposure in the last 10 years, while cortical bone (measured in the mid-tibia) reflects lifetime exposure. [PMID 21788910
] Tetraethyl & tetramethyl lead (CAS # 78-00-2 & 75-74-1) are covered separately.