Lead came

Total consumption of lead in the United States in 1993 reached 1,318,800 t. Of this, 766,000 t (58%) is allocated to battery use suppHed as either a mixed oxide or as metal. Approximately 95% of batteries are recycled and the lead recovered. In 1993, 908,000 t of lead came from secondary smelters and refiners compared to 350,000 t originating in primary mines and smelters (39). Approximately 51,000 t of lead was consumed in U.S. production of all oxides and chemicals appHcable to all industries other than batteries. Estimates include 8000 t for plastics, 6000 t for gasoline additives, 2000 t for mbber, and 30,000 t for ceramics, glass, and electronics. Lead is not used to any extent in dispersive appHcations such as coatings. 

Recommendation 5 (Figure 6-12) The bulk capacitor has been placed close to where the input supply leads came in, but the ceramic decoupling capacitor must be very close to the IC as indicated here. 

The other major route of lead absorption is the gastrointestinal tract. Dietary intake of lead reached average peak values of almost 0.5 mg per person per day in the U.S. around the 1940s. Much of this lead came from lead solder used in cans employed for canned goods and beverages. Currently, daily intake of dietary lead in the U.S. is probably only around 20 pg per person per... 

According to William Walsh of the Health Research Institute (HRI) in suburban Chicago, Beethoven s hair showed a lead concentration 100 times the normal levels. The scientists concluded that Beethoven s exposure to lead came as an adult, possibly from the mineral water he drank and swam in when he visited spas. 

Graphite is a shiny black mineral. It is also called plumbago and black lead. The name black lead came into use because graphite, like the soft metal lead, leaves a gray streak when it is rubbed over paper. It is the principal constituent of the lead" of lead pencils. 

The main catalyst site poison for many years was tetraethyllead [78-00-2]y C H ven after use of unleaded gasoline. Not only is lead a catalyst poison, but automotive source lead is also a health hazard (66). The source of this lead came from manufacture and distribution of leaded and unleaded gasoline in common transport equipment and storage facilities (67). In the eady 1990s, so Htde leaded gasoline was being distributed that Pb contamination was approaching zero (<0.26 ppm/L). 

Acetylcholinesterase inhibitors has been a productive approach in the design of insecticides starting with the phosphate esters such as malathion and continuing on to carbamate esters such as carbaryl. For the latter, leads came from two carbamate reversible cholinesterase inhibitors used in medicine, the natural product physostigmine and the synthetic derivative, neostigmine. 

An additional note on lead cames in a modem context is important. Lead is now extmded into cames by precisely measured machinery that can cut down greatly on the amount of lead used, and hence on the weight of the cames. Furthermore, addition of certain metals or metalloids, such as antimony, to the lead stmcture serves to strengthen the lead and give it a life exposed to the weather for perhaps many centuries. Stained glass windows can be further protected by the preventive conservation technique of protective isothermal glazing. 

---