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Lead is used as the metal, as alloys and as inorganic and organic lead compounds. Its main uses are:
* In storage batteries for cars (70 per cent of world production and increasing).
* For soldering, for example in guttering and electronic circuits.
* In paint---about 3.7 million pre-1970 homes in Australia have lead in old painted surfaces, and lead is still permitted above 0.1% in auto paints, marine, aircraft and other industrial paints.
* As sheathing for underground telephone and power cables. Increasingly plastics and aluminium are used instead of lead, though PVC sheathing contains lead.
* For noise attenuation, plumbing and radiation shielding.

The use of lead for glazing earthenware is illegal now but articles from Middle Eastern and Central American countries often have lead glazes. They should not be used for acidic drinks. Lead crystal decanters and glasses may leach some lead.

Although graphite is now used in 'lead' pencils, a Victorian Health Commission report found high levels of lead in paint on the outside of pencils (up to 18.6 per cent) and 1.6 per cent lead in the graphite core in some pencils.

Lead arsenate as an insecticide is now banned. The tin/lead solder in tin cans has to be protected by a lacquer coat in Australia. The use of lead cores at the centre of candle wicks is being reassessed. Since 1982 the Australian Standard for children's toys forbids the use of lead and lead alloys in toys, unless the lead is shielded. Imported lead toys, for example toy soldiers, can contain lead and one product was recalled in 2001.

Most brands of electrical and duct tape have lead in them---so cut them with a knife, not your teeth!

Health effects
Lead has no known biological use within the body. All lead is therefore a contaminant. Inorganic lead builds up in the bone and tissue, including blood. Lead accumulates in the bone for life and in the tissue until adulthood. The liver breaks down organic lead compounds but the products damage the brain and the nervous system. Children absorb lead more readily than adults. The Australian goal for blood lead levels is a maximum of 10 micrograms per decilitre (10mg/dL).

The main hazards are from inhaling airborne lead during building renovations or from lead mills and smelters, and from swallowing lead paint or dust or soil contaminated by past use of lead in petrol and paint. Small children are especially susceptible to this via normal hand-to-mouth activity. Water pipes in old houses may be made of lead (up to the 1930s) and lead solder for water pipes and fittings was allowed up to 1989, so drinking water may be contaminated.

Lead is readily absorbed through the skin if it is wet (e.g. with sweat) and the mere handling of lead objects will contribute to the lead burden of the body. Symptoms of lead poisoning have been known for 2,000 years. Mild symptoms are sleeplessness, irritability, fatigue, headaches, abdominal pain, vomiting and hyperactivity in children. Severe symptoms include convulsions, stupor, coma, brain damage and anaemia, and can lead to death.

Studies have established links with children between mild lead poisoning and reduction in IQ and changes in learning behaviour. Between five per cent (in rural communities) and 25 per cent (in inner-urban Sydney) of one to five year-old children suffer mild lead poisoning (in a 1996 study). The exposure of small children to lead, and their blood lead levels, can be drastically reduced by meticulous housekeeping and by ensuring a healthy diet. Advice on such measures can be obtained from the Lead Advisory Service Australia (www.lead.org.au; PO Box 161, Summer Hill, NSW 2130; phone 1800 626 086 or 02 9716 0132).

Environmental effects
Past use of lead in petrol has contaminated agricultural and urban soil. Soil near highways and from well-fertilised agricultural land is suspect. Vegetables grown near busy highways have been found to contain excessive amounts of lead. In old city houses the dust in the cavities above ceilings is likely to be contaminated from the past use of lead in petrol.

During renovation of old houses the dust and many surfaces will be contaminated with lead from paint, as will be garden soil. Up until 1950 paint used for wood and fibrocement was based on white lead. Paint for metal such as guttering used red lead.

Alternatives
Wash all soil off garden vegetables.

Seal old house paint with lead-free paint. When scraping back old paint, use water spray, wear a good quality mask (see Protective clothing) and collect all scrapings carefully on plastic sheeting laid down before you start then dispose of them safely; and ensure tradespeople working on your house follow suit (see Paints). There is also a product that comes as a sheet which strips the paint and can then be peeled off (see Paint strippers).

If you live in an old inner-city house it is worth having a specialist company remove the accumulated dust from above your ceilings, whether or not you are renovating and particularly if you have small children.

Avoid using old or amateur glazed pottery. Acidic drinks such as apple juice, and alcoholic drinks should not be stored in lead-glazed containers or lead crystal decanters.

 
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