Non-occupational/unknown source of lead absorption notifications

This section provides information on non-occupational/unknown source of lead absorption notifications from 2014 to 2022. 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 the Ministry of Health [1].

Risks to children

Young children, particularly 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].

Risks in adults

Lifestyle activities such as indoor rifle range shooting are one of the most common sources of non-occupational lead exposures. 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].

Prolongued 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 2023

1. Non-occupational lead absorption notifications have roughly doubled since the introduction of the new notifiable threshold in 2021.
   
   
2. Lead-based paint is the most common source of exposure, accounting for 30% of notifications since 2014.
   
   
3. Adult males in all 10-year age groups have considerably higher rates of lead absorption than females of the same age in 2021–22
   
   
4. Notification rates in Hawkes Bay, Taranaki and MidCentral public health units were roughly double the national rate in 2021–22.

To view more information about occupational lead in Aotearoa New Zealand, as well as downloadable figures and data, access the interactive report at the top of this page.

Information about the data

This indicator reports HSDIRT non-occupational/unknown source of lead absorption notifications from 2014 to 2022. The data was extracted from the HSDIRT system on 6 March 2023. 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.

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.

References

1. Ministry of Health. 2021. The environmental Case Management of Lead-exposed Persons. URL: https://www.health.govt.nz/publication/environmental-case-management-lead-exposed-persons (Accessed 09 August 2021)
   
   
2. Armstrong R, Anderson L, Synnot A, et al. 2014. Evaluation of evidence related to exposure to lead. Canberra: National Health and Medical Research Council. URL: www.nhmrc.gov.au/guidelines-publications/eh58 (accessed 13 October 2021).
   
   
3. Reuben A, Schaefer JD, Moffitt TE, et al. 2019. Association of childhood lead exposure with adult personality traits and lifelong mental health. JAMA psychiatry, 76(4), 418-425.
   
   
4. Russel M, Read D, Cook H. 2019. Firearms and lead. N.Z. Med. J, 132(1496), 69-71.
   
   
5. Centres for Disease Control. 2021. Lead; Information for Workers. Atlanta: Centres for Disease Control. URL: https://www.cdc.gov/niosh/topics/lead/health.html (Accessed 04 October 2022)