[NPMUG] Computer "E-Waste" story #2 - Lead Poisoning

[Dave Sevick]

http://en.wikipedia.org/wiki/Lead  ( the following are excepts from  
the site .... )

Lead (pronounced /ˈlɛd/) is a main-group element with symbol Pb  
(Latin: plumbum) and atomic number 82. Lead is a soft, malleable poor  
metal, also considered to be one of the heavy metals. Lead has a  
bluish-white color when freshly cut, but tarnishes to a dull grayish  
color when exposed to air. It has a shiny chrome-silver luster when  
melted into a liquid.
Lead is used in building construction, lead-acid batteries, bullets  
and shot, weights, and is part of solder,pewter, fusible alloys and  
radiation shields. Lead has the highest atomic number of all stable  
elements, although the next element, bismuth, has a half-life so long  
(longer than the estimated age of the universe) it can be considered  
stable. Like mercury, another heavy metal, lead is a potent neurotoxin  
that accumulates in soft tissues and bone over time. Lead poisoning  
was documented in ancient Rome, Greece, and China.

Health effects
Main article: Lead poisoning
Lead is a poisonous metal that can damage nervous connections  
(especially in young children) and cause blood and brain disorders.  
Because of its low reactivity and solubility, lead poisoning usually  
only occurs in cases when the lead is dispersed, like when sanding  
lead based paint, or long term exposure in the case ofpewter  
tableware. Long term exposure to lead or its salts (especially soluble  
salts or the strong oxidant PbO2) can cause nephropathy, and colic- 
like abdominal pains. The effects of lead are the same whether it  
enters the body through breathing or swallowing. Lead can affect  
almost every organ and system in your body. The main target for lead  
toxicity is the nervous system, both in adults and children. Long-term  
exposure of adults can result in decreased performance in some tests  
that measure functions of the nervous system. It may also cause  
weakness in fingers, wrists, or ankles. Lead exposure also causes  
small increases in blood pressure, particularly in middle-aged and  
older people and can cause anemia. Exposure to high lead levels can  
severely damage the brain and kidneys in adults or children and  
ultimately cause death. In pregnant women, high levels of exposure to  
lead may cause miscarriage. Highlevel exposure in men can damage the  
organs responsible for sperm production.
The concern about lead's role in cognitive deficits in children has  
brought about widespread reduction in its use (lead exposure has been  
linked to learning disabilities[10]). Most cases of adult elevated  
blood lead levels are workplace-related.[11] High blood levels are  
associated with delayed puberty in girls.[12] Lead has been shown many  
times to permanently reduce the cognitive capacity of children at  
extremely low levels of exposure.[13] There appears to be no  
detectable lower limit, below which lead has no effect on cognition.
In the 20th century, the use of lead in paint pigments was sharply  
reduced because of the danger of lead poisoning, especially to  
children.[14][15][16] By the mid-1980s, a significant shift in lead  
end-use patterns had taken place. Much of this shift was a result of  
the U.S. lead consumers' compliance with environmental regulations  
that significantly reduced or eliminated the use of lead in non- 
battery products, including gasoline, paints, solders, and water  
systems. Lead use is being further curtailed by the European Union's  
RoHS directive. Lead may still be found in harmful quantities in  
stoneware, vinyl (such as that used for tubing and the insulation of  
electrical cords), and brass manufactured in China. Between 2006 and  
2007 many children's toys made in China were recalled, primarily due  
to lead in paint used to color the product.
Older houses may still contain substantial amounts of lead paint.  
White lead paint has been withdrawn from sale in industrialized  
countries, but the yellow lead chromate is still in use; for example,  
Holland Colours Holcolan Yellow. Old paint should not be stripped by  
sanding, as this produces inhalable dust.
Lead salts used in pottery glazes have on occasion caused poisoning,  
when acidic drinks, such as fruit juices, have leached lead ions out  
of the glaze.[17] It has been suggested that what was known as "Devon  
colic" arose from the use of lead-lined presses to extract apple juice  
in the manufacture of cider. Lead is considered to be particularly  
harmful for women's ability to reproduce. For that reason, many  
universities do not hand out lead-containing samples to women for  
instructional laboratory analyses.[citation needed] Lead(II) acetate  
(also known as sugar of lead) was used by the Roman Empire as a  
sweetener for wine, and some consider this to be the cause of the  
dementia that affected many of the Roman Emperors.[18]
Lead as a soil contaminant is a widespread issue, since lead is  
present in natural deposits and may also enter soil through (leaded)  
gasoline leaks fromunderground storage tanks or through a wastestream  
of lead paint or lead grindings from certain industrial operations.
Lead can also be found listed as a criteria pollutant in the United  
States Clean Air Act section 108. Lead that is emitted into the  
atmosphere can be inhaled, or it can be ingested after it settles out  
of the air. It is rapidly absorbed into the bloodstream and is  
believed to have adverse effects on the central nervous system, the  
cardiovascular system, kidneys, and the immune system.[19]
[edit]Biochemistry of lead poisoning
In the human body, lead inhibits porphobilinogen synthase and  
ferrochelatase, preventing both porphobilinogen formation and the  
incorporation of iron intoprotoporphyrin IX, the final step in heme  
synthesis. This causes ineffective heme synthesis and subsequent  
microcytic anemia.[citation needed] At lower levels, it acts as a  
calcium analog, interfering with ion channels during nerve conduction.  
This is one of the mechanisms by which it interferes with cognition.
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