Some people will develop health problems or lead poisoning if they are exposed to enough lead. If untreated, lead poisoning can be serious.
People living in industrialised societies like New Zealand have some lead in their bodies. Lead is taken into the body through food, water and air. Most of this lead is not absorbed by the body. However, some people will develop health problems or lead poisoning if they are exposed to enough lead. If untreated, lead poisoning can be serious.
Where does lead come from?
Lead may come from a number of sources. These include old paint, plumbing materials in contact with drinking-water, and some industries, for example, battery manufacture.
With the removal of lead from petrol in 1996, the main source of non-occupational exposure to lead in New Zealand is lead-based paint on and around houses built before about 1970, but particularly before 1945. On many older houses, the old paint may still be in place, painted over or flaking off. When old paint is removed, the lead in it may settle in dust or soil.
There is potential for elevated lead levels in drinking-water from dissolution of lead pipes and solders, and tap fittings in homes. The amount of lead dissolved is dependent on, amongst other things, how corrosive the water is, what the pipes or fittings are made from and the amount of time the water is in contact with the pipe or fittings.
Who is at risk?
Infants and preschool children in contact with flaking paint or lead-contaminated dust or soil are particularly at risk of developing lead poisoning. This is because they often put into their mouths objects (like toys or their fingers) that may be contaminated with dust or soil. Paint on old cots or old toys, such as rocking horses or blocks, could be lead-based.
Young children absorb more of the lead they take in than older children and adults.
Adults are exposed to lead by breathing it in as dust from activities such as restoring and cleaning older houses. Not washing lead-contaminated hands properly before smoking or eating may cause exposure to lead.
The highest levels of lead in adults’ blood occur in industrial workplaces.
The lower blood lead levels generally found in non-occupational settings may have a small effect on blood pressure; they can also be a cause of cataracts in men 60 years and over.
Lead can be carried to the unborn child through the mother’s blood. Therefore, exposing the mother to lead through repainting, through her type of work (eg, car radiator repair, painting, battery manufacture) or through hobbies involving lead exposure (eg, leadlighting, indoor small bore rifle shooting) may affect the baby while it is still being formed.
Exposure to lead can cause premature birth or low birth weight as well as later problems with development.
Contact with low levels of lead does not cause any obvious illness. However, if untreated, low blood lead levels can affect the developing brain and may impair young children’s development and later performance at school.
High levels of lead can cause symptoms such as:
- stomach pains
- difficulty sleeping
- loss of appetite.
It is important to know, however, that there are many causes of these symptoms other than lead.
If untreated, very high blood lead levels can result in more serious problems and lead to brain damage or even death.
If you are uncertain if your child has been affected, ask your doctor for a blood test.
The early stages of lead poisoning are non-specific and affect the gastrointestinal and nervous systems.
Symptoms of lead poisoning that affects the nervous system can include:
- mood changes (such as depression or irritability)
- memory impairment
- sleep disturbance
- tingling and numbness in fingers and hands.
Symptoms of lead poisoning that affects the stomach and intestine can include:
- lack of appetite
- stomach pains
- weight loss.
In later stages, symptoms may develop in the blood, kidneys, bones, heart and reproductive systems and may, in extreme cases, cause death.
Diagnosing lead poisoning
Lead poisoning is diagnosed by measuring the amount of lead in the blood.
Treatment is available for lead poisoning
If you have any questions about lead poisoning, please discuss them with your nurse or doctor.
Protecting your child from lead poisoning
- Reduce exposure to sources such as lead-based paint and contaminated soil.
- Make sure your child has a good diet. Calcium and iron can help prevent your child’s body from absorbing lead and are essential for a healthy diet. Include foods that are a good source of iron and calcium in your child’s diet every day.
- Iron-rich foods include (lean) meat, chicken, and seafood. Cooked or canned dried beans (eg, kidney beans, baked beans), chickpeas, lentils, split peas and tofu contain iron, but it is not absorbed as well as from animal foods. Iron absorption is assisted by vitamin C, so serve alongside fruit or vegetables (eg, citrus fruits, kiwifruit, leafy green vegetables, broccoli, tomatoes, capsicums).
- To ensure an adequate calcium intake, children should be encouraged to consume at least two servings of milk or milk products each day. A serving is equivalent to 1 glass of (reduced fat) milk, ¾ cup yoghurt or 2 slices of cheese. If plant-based milk alternatives, such as soy, rice, almond or oat milk, are being used, ensure they are calcium-fortified.
- The Ministry’ Eating and Activity Guidelines Series (including the age-appropriate Food and Nutrition Guidelines series) describe a healthy diet.
- Make sure that your children wash their hands before they eat.
- Take special care with home renovations. If renovating older houses, seek advice about controlling leaded paint chips and dust. If the house was built or repainted before 1970, assume that the paintwork is lead-based, unless a test shows that it is not.
- Wash dummies and toys frequently, especially those used outside.
- Wet-dust floors, ledges, window sills and other flat surfaces at least once a week.
If your house is being repainted
For advice about how to protect yourself and your family from lead poisoning if your house is being repainted, go to Removing lead-based paint or talk to a health protection officer at your local public health unit.
Avoiding drinking-water containing lead
- Taps are main sources of lead that are found in drinking-water in most houses. Flush a small volume of water – about 500ml – from the cold tap before water is drawn for drinking, cooking, or brushing your teeth. You should also run a cold tap for about 30 seconds each morning, to flush out the water sitting in your pipes overnight.
- If your house has a rainwater supply, check your roof and guttering for materials that may contain metals that could contaminate the water: lead flashing, lead-headed nails, and lead paint, for example. These should be replaced if you find them.