Non-occupational lead absorption notifications

This section provides information on non-occupational/unknown source of lead absorption notifications from 2014 to 2023. The data comes from the Hazardous Substances Disease and Injury Reporting Tool (HSDIRT). Data before 9 April 2021 relates to a blood lead notification threshold of ≥0.48 µmol /L. From 9 April onwards, the notifiable threshold was set as ≥0.24 µmol/L. While no safe level of exposure to lead has been found, these are the notifiable thresholds currently set by Te Whatu Ora - Health New Zealand [1].

Children at higher risk from lead exposure

Young children, particularly those under six years are at higher risk from lead exposure than adults because:

• their activities and behaviour (eg, hand-to-mouth) result in greater exposure
• their developing nervous system is sensitive to lead
• they absorb approximately 50% of ingested lead compared to 10–15% in adults
• their diet may be low in calcium or iron thus increasing lead absorption in the body [2]

Children with pica (a serious eating disorder characterised by repetitive consumption of non-food items) are more at risk than other children from lead exposure, especially if eating lead-contaminated soil or paint flakes [3].

Prolonged lead exposure linked to depression and serious health risks in adults

Lifestyle activities such as indoor rifle range shooting are one of the most common sources of non-occupational lead exposure. While lead-based paint on older buildings is generally well recognised as a source of lead exposure in New Zealand, there is less awareness of the risk of lead exposure from firearm use [4].

Prolonged lead exposure in adults can result in a range of psychological and physiological outcomes, including depression, high blood pressure, heart and kidney disease, and reduced fertility [5]. Exposure of pregnant women to high levels of lead can cause miscarriage, stillbirth, premature birth and low birth weight.

Key facts from 2024

1. Total lead absorption notification rates remained high for adults in 2023, but rates for children aged 0–14 years decreased.

2. Lead-based paint was the most common source of exposure, accounting for 27% of notifications since 2014.

3. Males aged 65–74 years had higher lead notification rates than males in other age groups.

4. The Whanganui district had the highest lead notification rates in 2021–22 and 2022–23.

Information about the data

This indicator reports HSDIRT non-occupational/unknown source of lead absorption notifications from 2014 to 2023. The data was extracted from the HSDIRT system on 18 March 2024. Updates or additions made to HSDIRT after this date are not reflected in this Surveillance report.

Repeat blood lead tests taken within a year of the original test have been excluded from this data unless further investigation has resulted.

This data source only includes cases that were notified and will be underestimating the total burden of disease and injury caused by lead exposures. Also, a case will not be included in the analysis if the GP is unaware of the tool and does not use it to notify cases or the laboratory does not directly notify the blood lead result to EpiSurv.

Lead absorption is challenging to detect based on symptoms alone as many cases are asymptomatic and will, therefore, not be seen by a doctor and/or have a blood lead test. In some instances a blood lead test will occur because of awareness by the individual to a known exposure.

For additional information, see the metadata linked at the top of this page.