• Lead: effects on human health

• Lead poisoning

• Lead is a kind of toxic and heavy metal, which may adversely affect people’s health if they are exposed to large amounts. Therefore in daily life, you are advised to avoid lead exposure wherever possible. Lead mainly affects human health via the food chain, water and air.
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• Source: http://www.medindia.net/patients/patientinfo/lead-poisoning-in-children-symptoms.htm
• Symptoms of lead exposure
• Lead poisoning can be a serious public health threat with no unique signs or symptoms. Early symptoms of lead exposure may include:
• - persistent fatigue
• - irritability
• - loss of appetite
• - stomach discomfort and/or constipation
• - reduced attention span
• - insomnia
• Failure to treat lead poisoning in the early stages can cause long-term or permanent health damage, but because of the general nature of symptoms in the early stages, lead poisoning is often not suspected.
• In adults, lead poisoning can cause:
• - poor muscle coordination
• - nerve damage to the sensory organs and nerves controlling the body
• - increased blood pressure
• - hearing and vision impairment
• - reproductive problems (e.g., decreased sperm count)
• - retarded fetal development even at relatively low exposure levels.
• In children, lead poisoning can cause:
• - damage to the brain and nervous system
• - behavioral problems
• - anemia
• - liver and kidney damage
• - hearing loss
• - hyperactivity
• - delayed development
• - in extreme cases, death
• Although the effects of lead exposure are a potential concern for all humans, young children (under seven years old) are most at risk (Reagan and Silbergeld, 1989). This increased vulnerability results from a combination of the following factors:
• Children typically have higher intake rates (per unit body weight) of environmental media (such as soil, dust, food, water, air, and paint) than adults, since they are more likely to play in dirt and put their hands and other objects in their mouths;
• Children tend to absorb a higher fraction of ingested lead from the gastrointestinal tract than adults;
• Children tend to be more susceptible than adults to the adverse neurological and developmental effects of lead;
• Iron or calcium deficiencies , which are common in children, may facilitate lead absorption and exacerbate the toxic effects of lead.
• The national average blood lead levels in children have dropped over time as our understanding of lead risk has evolved, and as efforts are undertaken to reduce exposure to lead. While the banning of lead paint and lead in gasoline were national efforts to stop childhood lead poisoning, contaminated sites require site-specific cleanups to reduce exposure to populations nearby.
• The Centers for Disease Control (CDC) has identified that the current blood lead level of concern in children is 10 micrograms (µg) of lead per deciliter (dL) of blood (10 µg/dL); however, adverse effects may occur at lower levels than previously thought. In January of 2012, an advisory panel to the CDC recommended lowering the level that triggers intervention.
• Some developed countries have regulations for the lead content in some goods such as the following which apply in the USA:
• The lead content for children’s products must be less than 100PPM
• That for lead paints or other surface coatings must be less than 90PPM
• That for leather must be less than 300PPM
• That for vinyl plastics must be less than 200PPM
• That for other materials must be less than 300PPM (except crystal)
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• Source: http://www.texaschildrenshealthplan.org/leadscreening/index.htm

• Sources of lead in daily life

• Food
• The skin of vegetables and fruits, canned goods, popcorn, puffed food, preserved egg, white steamed bread and printed packaging food may contain large amounts of lead.
• Water
• Lead may get into drinking water through pipes which are corroded, and if water is acidic, lead will get into water much more easily.
• Air
• The polluted air from automobile exhausts contains some lead and, in addition, smoking will also indirectly produce a small amount of lead.
• Other resources
• Cosmetics, hair dyes, paints, crayons, toys, chemical fertilizers, pesticides, fuel, overalls and some other sources of environmental lead, including some drugs, candles and so on.

• Sources of industrial lead pollution

• Lead pollutes the natural environment mainly through the atmosphere, water and soil. Besides direct emissions of excessive amounts of lead pollution gases, waste water and waste residues, other sources are paints, coatings, batteries, smelting, hardware, machinery and electroplating.
• Note:
• Is a pencil made of lead?
• As mentioned in the history section, nowadays, the core in pencils is made of graphite, not lead.
• However, it may not be possible to avoid the surface paint on some inferior pencils containing lead, so please stop children from biting pencils.

• Major foods for removing lead from the body

• 1. Food that is rich in protein, including milk, eggs, quail eggs, beef and bean products etc.
• 2. Food that is high in calcium, including dried small shrimps, milk, bean products, crab, sesame, shepherd's purse, celery, radish leaves, leaf lettuce, almonds, melon seeds, peach kernels, oranges, potatoes and bone soup.
• 3. Food that is rich in iron, including pig’s blood, pork liver, pork loin, black fungus, red dates, eggs, purple carrots, celery, carrots, tomatoes, hawthorns, peaches, strawberries, longans etc.
• 4. Vitamins C, B1, B2, B6, B12, microelements and folic acid.
• 5. Others: garlic, pectin (yoghurt).