Lead Poisoning

A friend of mine was told that her son who is almost 4 is autistic due to lead poisoning. And now her second son, who is 2 has also been found to have high levels of lead.


They live in Sai Kung in a house that is not too old, with no smelters or plants anywhere nearby. I wonder how both children could have developed high levels of lead in their system.


Is there anyway of testing parts of the house for levels of lead and by that I mean is there a company that does such testing?


Anyone?

Lead poisoning (also known as saturnism, plumbism, Devon colic, or painter's colic) is a medical condition caused by increased levels of the metal lead in the blood. Lead may cause irreversible neurological damage as well as renal disease, cardiovascular effects, and reproductive toxicity.


Humans have been mining and using this heavy metal for thousands of years, poisoning themselves in the process due to accumulation and exposure. These dangers have long been known, though the modern understanding of their full extent and the small amount of lead necessary to produce them is relatively recent; blood lead levels once considered safe are now considered hazardous, with no known threshold. Lead has also been found in some pool paint - especially those painted by lead-based epoxy paint.[1]


Symptoms and effects


The symptoms of chronic lead poisoning include neurological problems, such as permanent and temporary reduced cognitive abilities, or nausea, abdominal pain,[11] irritability, insomnia, metal taste in the mouth, excess lethargy or hyperactivity, chest pain, headache and, in extreme cases, seizures, comas, and death. There are also associated gastrointestinal problems, such as constipation, diarrhea, vomiting, poor appetite, weight loss, which are common in acute poisoning. Other associated effects are anemia, kidney problems, and reproductive problems. It has been shown to cause permanently reduced cognitive capacity (intelligence) in children, with apparently no lower threshold to the dose-response relationship (unlike other heavy metals such as mercury).[16]


In humans, lead toxicity sometimes causes the formation of a bluish line along the gums, which is known as the Burton line, although this is very uncommon in young children. Blood film examination may reveal "basophilic stippling" of red blood cells, as well as the changes normally associated with iron-deficiency anemia (microcytosis and hypochromasia). However, basophillic stippling is also seen in unrelated conditions, such as megaloblastic anemia caused by vitamin B12 (colbalamin) and folate deficiencies.[17]


Lead affects the peripheral and central nervous system. The most common sign of peripheral neuropathy due to chronic lead poisoning is painless wristdrop (weakness of the extensor muscles of hand) which usually develops after many weeks of exposure.


A direct link between early lead exposure and learning disabilities has been confirmed by multiple researchers and child advocacy groups.


A May 2000 study by economic consultant Rick Nevin theorizes that lead exposure explains 65% to 90% of the variation in violent crime rates in the U. S..[18][19] A July 2007 paper by the same author claims to show a strong association between preschool blood lead and subsequent crime rate trends over several decades across nine different countries.[20] These results were discussed in a July 2007 Washington Post article, reviving interest in the subject.[21] Nevin's results reflect peer reviewed findings by Dartmouth political scientist Roger D. Masters,[22][23] and similar work is being done by other researchers. Amherst economist Jessica Reyes' working paper[24] and Masters' work are both pre-publication and available online.


Chronic lead poisoning can produce a "lead hue," with a lividity and pallor, and a deposit of lead in the gums may occur, sometimes referred to as the "lead line."[25]


It has been suggested in studies that lead may elevate blood pressure in adults who are exposed to blood level concentrations <20 ug/dL. In humans, the link between blood lead and blood pressure was influenced by the subjects sex or race. Bone lead concentration was a predictor of hypertension in two different studies. The risk for lead-associated hypertension may be lowered by preventing chronic workplace blood lead concentrations from 20-30 ug/dL to <10 ug/dl.


The effects of bone lead levels on heart rate variability are stronger in patients with metabolic syndrome. [4]


People who have been exposed to higher concentrations of lead may be at a higher risk for cardiac autonomic dysfunction on days where the ozone and fine particles are higher. [26]


Blood lead concentrations of 20-40 ug/dL have been associated with decreases in neuro-cognitive function. It was found in a large group of current and former inorganic lead workers in Korea that blood lead levels in the range of 20-50 ug/dL were correlated with neuro-cognitive defects. High current blood lead concentrations were correlated with poorer performance on neuro-cognitive function tests. [27]


More... http://en.wikipedia.org/wiki/Lead_poisoning