Mount Isa Children

Lead exposure and your child

Wash hands regularly

Remember to regularly wash and dry hands, especially before preparing food and touching or playing with children. Children’s hands need to be kept as clean and dry as possible, sticky hands will pick up a lot more lead dust than dry hands, so wash and dry children’s hands before and after eating.

Children should be encouraged to eat at a table or seated in a high chair so that dropped food cannot be picked up off the floor and eaten. Place old newspapers around their chairs for quick and easy cleaning purposes.

Eat breakfast

Remember to eat breakfast. A child who does not eat particularly after fasting (e.g. sleeping) can absorb considerably more lead than a child who has eaten.

How does lead enter our bodies?

Lead can enter the body through inhalation (breathing in) of lead dust particles and through ingestion (the eating and swallowing) of lead contaminated food, water or soil and paint chips as well as through contaminated hand to mouth movements.

Who is at most risk of high blood lead levels?

  • Children under 4 years of age
  • People who work in a lead related industry

Why is lead in young children such an issue?

Pre-school age children and foetuses are the most vulnerable to health effects of lead.

Blood lead levels at or above the national standard of 5µg/dL interfere with the development of organ systems, in particular the central nervous system, which affects babies and children more than adults as their bodies are rapidly developing.  Adverse effects in neurobehavioural function, particularly intellectual performance (decrement of 1-3 IQ points per 10µg/dL increment in population blood lead levels), impaired haemoglobin synthesis and vitamin D metabolism, appear to be the most sensitive effects of lead exposure.

This increased vulnerability results from a combination of factors including:

  1. Infants and toddlers are at greater risk due to increased exposure (mouthing behaviour), increased ability to absorb lead and the susceptibility of their  rapidly developing central nervous systems.  Older children, adolescents and non-occupationally exposed adults exhibit near normal blood lead levels unless significantly exposed during early life.
  2. Young children are more likely to play in dirt and to place lead contaminated hands and other objects in their mouths. This increases the opportunity for lead to be ingested.
  3. Nutritional deficiencies of iron or calcium, which can occur in some children, may facilitate lead absorption and exacerbate the toxic effects of lead.

How are children most likely exposed to lead?

There are a number of exposure sources that young children are more susceptible to than adults. These include:

  • Dust containing lead – A significant source of lead can come from dust that enters the home environment via prevailing winds that blow dust containing lead from the smelter.
  • Lead based paint – Although much less prevalent now, an important source of lead exposure in older homes was contact with interior or exterior surfaces that had been painted with lead-based paints. Children could be exposed to lead by eating chips that fall off the walls as the paint ages, by chewing on painted cribs, or by breathing dust when paint is sanded off walls during renovation.
  • Home renovating – Particularly in older homes where paint containing lead was used and where lead dust may have accumulated over a period of time in wall cavities or in ceilings.
  • Physical contact with contaminated people, clothing items and vehicles – Employees and Contractors working at a mine site are at risk of taking lead particles off site on their body, via their hair, hands, clothing, boots and vehicles. As such strict personal hygiene and site work protocols are in place to ensure this “take home” lead exposure is minimised. All employees and contractors are required to shower before they leave the site, and all works clothes including boots remain on site. All vehicles leaving the site are required to pass through a vehicle wash to remove any potential lead dust entering the community.
  • Rain water – Can be an exposure source if used for drinking and cooking purposes.  Boiling rain water does not remove lead and does not reduce contamination from lead.

Lead exposure and your child in Mount Isa – lifestyle impacts

  • Eating a healthy diet is important for everyone to help prevent disease and to maintain good health. Research shows that good nutrition can help reduce lead absorption as well as helping to achieve normal growth and development. It is therefore important that children and families eat a healthy diet that consists of a variety of foods from the five food groups. Infants that consume diets rich in zinc, iron and calcium have shown to have lower blood lead levels than in those infants consuming diets deficient in these elements.
  • Verandah’s, porches, doorsteps and entryways can be areas heavily loaded with lead. Large amounts of lead can be brought into the entryway area on shoes even after just 1 or 2 steps on a lead contaminated surface. Keeping these areas clean and free from dust is important in reducing possible exposure in children.
  • Houses are subject to substantial ongoing airborne contamination, particularly through open doors and windows when prevailing winds are coming from the smelter.
  • Studies on the effects of lead in children have demonstrated a relationship between exposure to lead and a variety of adverse health effects. Although no threshold level for these effects has been established, the available evidence suggests that lead toxicity may occur at blood lead levels of 5 – 15 µg/dL.
  • The efficiency of lead absorption from the gastrointestinal tract is greater in children than in adults. Adults absorb about 10-15% of ingested lead, whereas children’s less mature digestive systems can absorb as much as 50%, because lead resembles calcium and children’s gastrointestinal tracts take up calcium at greater rates than adults (for growing bones).
  • Exposure to lead begins before birth with its transference from the maternal blood circulation and increases rapidly in the first years of life as exposure to environmental lead increases.
  • The major and most rapid increase in blood lead occurs during the first 12 months of a child’s life peaking at 18 months.
  • Normal mouthing behaviours observed in infants and toddlers produces a significant and easy source of lead exposure. Lead contaminated dust is readily and rapidly loaded onto fingers and other non-food items from contact with floors.
  • Substantial amounts of lead can be found on children’s hands at all ages. While outdoors, their hands accumulate more lead dust than during the equivalent time indoors. After washing, the amount re-accumulates quickly. The amount of lead contamination on a child’s hand has been directly correlated to their lead in blood level.
  • At this age and size infants need only small uptakes of lead (30-50µg/day) to push their blood lead levels up to 15µg/dl. Toys or fingers can commonly have 5µg or more of lead on them which can become a significant exposure pathway.
  • A number of studies of all young children, has found that geographic area, house construction, pets (cats more so than dogs), teething, diet, carrying bottles around, eating while on the floor and male gender, tended towards higher blood lead levels.