Lead Poisoning - An Environmental Hazard

Lead poisoning was once far more prevalent than it is today. This has resulted in a lack of awareness of the risks that still exist for today's community. Following are some prevention tips which are highly relevant in today's society.

The danger of contamination was brought home to the community of Esperance on Western Australia's south coast when, in 2007, thousands of wild birds died from contamination by ore being transported from Wiluna in the goldfields to the Esperance port. After testing, elevated levels were found in a number of adults and children. Water tanks were also found to be contaminated. This resulted in a ban on export of the mineral through the port.

The element occurs naturally within the earth and is a soft greyish-blue colour. When absorbed into the body, it is retained for long periods of time. Repeated exposure to low levels results in an accumulation of the toxins causing pain and illness. In the human body, absorption  affects the production of haemoglobin in the blood. This results in tiredness and breathlessness on exertion. The liver and kidneys can also be affected.

Being smaller and lighter, children are likely to absorb up to five times the amount of adults. Even relatively low levels have the potential to affect a child's intellectual development and behaviour.

Developing foetuses can also be affected as the mineral can cross the placenta. Apart from the increased risk to pregnant women and children, those with iron and calcium deficiencies are likely to ingest more lead and show greater sensitivity.

The mineral can enter the body through the mouth, lungs or skin. Children under five are more at risk of ingestion because of their tendency to put items into their mouths. Water in guttering from very old houses may pass through lead plumbing, leading to the ingestion of small amounts. In Australia, there has been no installation of domestic water pipes made from this material for at least 40 years. Occasionally, water from hot water urns has been found to contain some lead but this is not usually a problem for young children.

Some forms of crystal contain lead although they are usually labelled to indicate this. New lead crystal ware contains a layer of noxious particles loosely bound to the glass surface. If acidic liquids and alcoholic beverages are stored in new crystal ware of this type, there may be high levels leached into the liquids.

Some pottery containers glazed with lead may contaminate food because of leaching.

Legislation now prohibits the use of paints containing more than 0.1% lead. Toys, furniture, fences and surfaces of non-industrial premises are sometimes coated with paint containing lead. Old, flaking paint is more suspect than modern paints. Automotive and marine paints may contain more than 0.1% but must be labelled to show this. However when working with fresh paints or restoring painted surfaces, contaminated fumes and dust may be generated.

Lead PaintCredit: Wikimedia

A major source of exposure is clothing contaminated during work or hobby operations eg laundry operators. Soil around a home may be contaminated from past or present activities such as battery recycling, radiator maintenance, removing paint, spray-painting boats or cars, and soldering.

Air-borne particles contribute to contamination of soil, water and food. Levels may rise during DIY activities and hobbies including car engine maintenance, making lead sinkers, panel beating or other body work on cars and boats, sanding and/or stripping old paint, flame cutting, melting, grinding, burning or sanding any products containing lead.

Up to 90% of lead in the atmosphere comes from the exhaust fumes of cars using leaded petrol. A major source of intake is the intentional or accidental inhalation of exhaust fumes.

Burning old wood painted with lead-based paints will cause pollution of the atmosphere.

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Industries such as lead mining, smelting and those that use lead products contribute to airborne lead. Pollution control measures need to be in place to prevent such pollution of the air. Western Australia has only one small lead mine but there are many industries using such products.

Symptoms of exposure are difficult to recognise. It can be absorbed through the skin from contaminated clothing, soil, hands, etc but such absorption is minimal. Absorption through the skin can be increased by certain solvents present in petrol.

Unless an adult works with lead they are not likely to be over-exposed. However some children may be over-exposed. Exposure should be minimised as much as possible to reduce blood lead levels, particularly in children.

In 1993 the NHRMC set a specific goal for all Australians to have a blood level of below ten micrograms per decilitre. A national survey in 1995 found that more than 90% of Australian children had blood levels well below the target set.

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There is no reason for complacency however. There are several ways in which contamination can be avoided or at least minimised.

  • Pregnant women and young children should keep well away from areas likely to be contaminated. Activities which generate contaminated fumes or dust should be avoided.
  • If working with lead products, work in an area which can be isolated and readily cleaned thus avoiding contamination of the house or garden.
  • When welding, heating, flame cutting or burning products which contain lead, wear a respirator fitted with the appropriate filters. Keep children away from these activities.
  • When renovating paint surfaces on older properties, thoroughly clean the areas first removing paint flakes and/or dust with an industrial vacuum cleaner fitted with filters or a wet rag or mop.
  • Instead of using blow torches or sandpaper to remove leaded paint, use chemical paint strippers. Such strippers can themselves be toxic so read the label and follow directions.
  • Painted wood should not be burnt.
  • After working with lead or leaded materials, be sure to wash your hands thoroughly. Do not eat, drink, smoke or interact with children before washing your hands.
  • If working at home with lead-based products, be sure to wash any home-grown fruit and vegetables before eating.
  • Be just as careful with contaminated clothing. Keep such clothing in a plastic bag until it can be washed. Don't interact with others, especially children, while wearing contaminated clothing.
  • Avoid buying food in soldered cans. Look for welded cans.
  • Lead crystal glassware and glazed pottery should be soaked for 24 hours in vinegar before being used to store food or drink. This will allow any lead to leach out.
  • Avoid using petrol as a solvent and wear non-absorbent gloves when handling petrol or servicing vehicles.
  • Do not dispose of waste petrol or oils in the backyard. Find a disposal place which accepts such products.
  • Run your car on unleaded petrol if possible.
  • Children likely to be subjected to lead should be tested regularly for blood lead levels. This can be done by your GP.

Items containing or contaminated with lead should not be discarded with general household rubbish nor should such items be buried in the backyard. Items such as old car batteries, radiators and lead flashing can be recycled.