Non-occupational/unknown source of lead absorption notifications

This section provides information on non-occupational/unknown source of lead absorption notifications from 2014 to 2020. The data comes from the Hazardous Substances Disease and Injury Reporting Tool (HSDIRT), and it includes data with a blood lead notification threshold of ≥0.48 µmol /L, which has since been lowered.

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 (Armstrong et al 2014)

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.

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 (Russell et al 2019).

Lead can cause long-term health effects in adults, including increased risk of high blood pressure and kidney damage (WHO 2020). Exposure of pregnant women to high levels of lead can cause miscarriage, stillbirth, premature birth and low birth weight.

This section presents non-occupational lead absorption notifications based on a blood lead notification threshold of ≥0.48 µmol /L, which has since been lowered to 0.24 µmol/L on 9 April 2021. 

Documents

Metadata: Non-occupational/unknown lead absorption notifications Download report PDF
Factsheet: Non-occupational/unknown source of lead absorption notifications (Nov 2021) Download report PDF

The non-occupational/unknown source of lead absorption rate has decreased since 2014

In 2020, there were 62[1] non-occupational/unknown source of lead absorption notifications out of 110 lead notifications from all exposure sources. The non-occupational/unknown source of lead absorption notification rate has decreased from 2.1 per 100,000 in 2014 to 1.2 per 100,000 in 2020. The nationwide lockdown from COVID-19 may have contributed to the low rate in 2020.

Figure 1: Non-occupational/unknown source of lead absorption notification rate, by year

[1] There were 11 cases reported in both occupational and non-occupational/unknown categories. Therefore, these cases can add to more than the total number of lead notifications.

Over 80% of the non-occupational/unknown source of lead absorption cases were males

In 2014–20, 81% of the non-occupational/unknown source of lead absorption notifications were males (474 out of 587 non-occupational lead notifications), while 18% (105 notifications) were females and for 1% (8 notifications) sex was unknown.

Boys in the 0–4 year age group had higher blood lead levels than girls of the same age group

In 2014–20, out of all the age groups, only boys in the 0–4 year age group had higher blood lead levels than girls of the same age group. Other than that, there were no significant differences in blood lead levels from non-occupational exposures between sexes (Table 1).

Table 1: Median blood lead level, interquartile range and number of non-occupational/unknown source of lead notifications by age group and sex, 2014–20

Non-occupational/unknown source of lead absorption notification rate among European/Other ethnicity is over three times the rate among Māori

In 2014–20, people of European/Other ethnicity were 3.3 times as likely to have non-occupational/unknown source of lead absorption as Māori. European/Other ethnic group had the highest reported non-occupational/unknown lead absorption notification rate (1.7 per 100,000; 372 notifications), followed by Pacific Peoples (1.3 per 100,000; 28 notifications). However, 20% of the notifications listed ethnicity as ‘unknown’ (Table 2).

Table 2: Non-occupational/unknown source of lead absorption notifications and rates, by prioritised ethnic group, 2014–20

Lead-based paint remained the most common source of non-occupational lead exposure since 2014

In 2020, there were 62 non-occupational/unknown lead absorption notifications. Since 2014, the most common sources of non-occupational lead exposure were lead-based paint, indoor rifle range and bullet/sinker manufacture (Table 3). Sixteen notifications had an unknown lead source in 2020. Other common non-occupational sources identified in 2014–20 were pica, gunshot wound, bullet/sinker manufacture and traditional medicines or cosmetics.

Table 3: Number of non-occupational or unknown lead absorption notifications, 2014–20

 Identifying people with potential lead exposure can be challenging, especially through recreational activities or hobbies, where signs and symptoms do not appear until dangerous amounts have accumulated (BPAC 2021). However, the primary source of lead exposure, especially for young children, is in their home. In 2020, there were four lead exposure notifications involving children aged under 15 years. Three of them had pica and had lead contamination in their homes.

no safe level of lead

People exposed to lead-based cosmetics or traditional medicines have relatively higher blood lead levels

In 2014–20, among those who were notified, people exposed to lead-based cosmetics or traditional medicines (eg, Ayurvedic remedies) had relatively higher blood lead levels compared to other sources of non-occupational/unknown source of exposures (Table 4).

Table 4: Median blood lead level, interquartile range by non-occupational/unknown source of exposures and number of notifications, 2014–20

Wairarapa DHB and Taranaki DHB Public Health had the highest reported rate of non-occupational/unknown lead absorption

In 2014–20, the Wairarapa DHB (6.5 per 100,000; 21 notifications) and Taranaki DHB Public Health Unit (4.6 per 100,000; 39 notifications) had the highest reported rate of non-occupational/unknown source of lead absorption among DHBs and PHUs respectively (Table 5).

Table 5:Non-occupational/unknown source of lead absorption notification rate and number of notifications, by DHB and PHU, 2014–20

 

Information about the data

This indicator reports HSDIRT non-occupational/unknown source of lead absorption notifications from 2014 to 2020. The data was extracted from the HSDIRT system on 5 March 2021. Updates or additions made to HSDIRT after this date are not reflected in this factsheet.

Data have sometimes been pooled to give sufficient numbers for analysis.

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

Crude rates presented in this factsheet do not take into account varying age distributions when comparing between populations.

For additional information, see the metadata.

References

1.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).

2.BPAC. 2021. Lead absorption notification levels have reduced. Occupational medicine: Public Health URL: https://bpac.org.nz/2021/lead.aspx (Accessed 8 September 2021)

3.Centers for Disease Control and Prevention. 2017. Pica behaviour and Contaminated Soil. URL: http://medbox.iiab.me/modules/en-cdc/www.cdc.gov/healthcommunication/toolstemplates/entertainmented/tips/Pica.html (Accessed August 2021).

4.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.

5.World Health Organization. 2020. Lead poisoning and health, URL: https://www.who.int/news-room/fact-sheets/detail/ lead-poisoning-and-health (accessed 13 October 2021).

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