Whakakinotia te kāinga me te whenua Land and home contamination

Land used to build homes could be contaminated by previous hazardous activities including:

• agriculture, orcharding and market gardening
• landfill
• timber treatment
• other industrial uses.

The Ministry for the Environment explains:

• what is contaminated land
• how land can become contaminated
• when it becomes a problem.

You can get information on how the land you live on has been used in council LIM (Land Information Memorandum) and property files. You can also request it from your local council.

Contaminated land – Ministry for the Environment (external link)

Older homes in Aotearoa New Zealand were often built using products and materials that are not permitted today for health and safety reasons.

These buildings are no risk to your health while they remain in good condition. The risks increase:

• when the materials degrade (flake, crumble)
• when the materials are removed or disturbed (drilling, sanding)
• during renovations and building work
• after a fire.

Two common hazardous building materials are asbestos and lead-based paint. If your home was built in the mid-1980s or earlier, presume it contains one or both of these materials. They can lie beneath layers of more recently added paints or products.

There are no health effects for most people living on contaminated land or in a well-maintained home containing older building products. But you may want to think about it more closely if you have young children or are pregnant.

In New Zealand homes built before the mid-1980s, asbestos is mostly found in:

• asbestos cement (cladding, roof tiles)
• floor backing
• textured ceilings
• lagging around pipes
• insulation.

Health risks from asbestos

Asbestos is a naturally occurring mineral made up of small fibres. When asbestos dust or fibres are released into the air, they become a health risk. The risk increases the more asbestos dust you breathe in and the longer you are exposed to it. There is no safe level for asbestos.

Asbestos dust and fibres can scar your lungs and cause the lung lining to thicken. It puts you at risk of lung disease and a rare lung cancer called mesothelioma, which can take 15 or more years to develop.

If you think you have been exposed to asbestos in the past, tell your healthcare provider if you:

• have a persistent cough
• have breathing problems
• are coughing up blood.

Mesothelioma – Cancer Society (external link)

Asbestos-related diseases – Patient.info (external link)

The risk from lead in the home is from:

• lead-based paints in older homes (the main risk)
• old lead pipes, solders and tap fittings
• lead roof flashings, where water is collected.

You would find it hard to tell a lead-based paint by its appearance.

When old paint is removed, the paint and lead in it may settle as dust or collect in soil.

Health risks from lead

Lead is a toxic metal. If you have minimal contact with substances containing lead, it causes no obvious illness. With more contact your blood levels of lead can rise, and you may have:

• nervous symptoms
• lack of appetite
• digestive problems
• weight loss.

In children, low levels of lead in the blood can affect the developing brain if left untreated.

You can have your blood tested for levels of lead, and lead poisoning can be treated. If you think you have been exposed to lead, talk to your healthcare provider. (internal link)

Lead poisoning – Health New Zealand | Te Whatu Ora (external link)

Arsenic is a naturally occurring substance. It has been used to kill insects that attack animals, timber, vegetables and fruit.

Land may contain higher levels of arsenic if it was once used:

• or treating timber
• for agriculture and orcharding (arsenic-based pesticides)
• as a scrapyard
• for sheep (from sheep dip treatments).

Health risks from arsenic

High arsenic levels are usually caused by:

• contaminated food and water
• for pēpi or young tamariki, putting soil or dust into their mouths.

Consuming arsenic is not always harmful. Small amounts every day over a long time can have no obvious effects. Your body gets rid of it.

Moderate amounts of arsenic over many years can cause:

• skin changes
• damage to your heart and other organs
• cancer.

Swallowing too much arsenic in a short time (hours or days) can cause arsenic poisoning.

Medical testing for arsenic is not often used. If you are unwell or concerned, you should talk with your healthcare provider.

For normal daily activities, contamination on your property is unlikely to be enough to cause health issues. The risk to your health is low.

If you know your property is contaminated (and even if you are not sure), you can take some precautions.

• Wash your hands and skin after touching soil, before preparing food or eating, and before bed.
• Wear gloves for gardening.
• Grow vegetables in clean soil at least 30cm deep.
• Wash fruit and vegetables from the garden.
• Cover contaminated ground with clean soil and grass.
• Make play spaces for tamariki safe (not on bare earth).
• Keep soil outside (remove shoes, mop floors).
• Stop your pets from digging and running mud through the house.

Site contaminants and health – Health New Zealand | Te Whatu Ora [PDF, 271 KB]

If your water is from a piped water supply, it is tested to meet the New Zealand drinking water standards.

If you use a bore or well for drinking water or irrigation, you should have it tested four times a year for bacteria and once a year for nitrate.