Levels of lead in New Zealand adults and children - Jonathan Coakley Environmental Scientist Tonkin + Taylor (Wellington)
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Levels of lead in New Zealand adults and
children
Jonathan Coakley
Environmental Scientist
Tonkin + Taylor (Wellington)
Outline • Overview of lead in humans • Previous studies • New Zealand Biological Monitoring Study • Policy implications • Recommendations
15 Avril 2019 Getty Images
Shutterstock
A brief history of lead exposure
• 1900’s – European countries restrict use of white lead in paint
• Early 1970’s – Japan/USA/Canada restrict lead in gasoline, introduce
unleaded gasoline
• 1974 – New Zealand regulates lead solder in canned foods
• 1970s/1980s – lead in paint gradually phased out
• 1986 – Unleaded petrol becomes available in New Zealand –
estimated that 1/3 of blood lead comes from lead in petrol
• 1996 – Leaded petrol is removed from NZ pumps
Wilson N, Horrocks J. Lessons from the removal of lead from gasoline for controlling other environmental pollutants:
a case study from New Zealand. Environ Health. 2008;7(1):1-10.Previous New Zealand studies
• 1972-1973 birth cohort (Dunedin Multidisciplinary Health and Development Study)
• Observed from age 11 to 38
• Blood lead measured at age 11 (1983 – 1984)
– High levels (mean 10.99 µg/dL) among all children regardless of
socioeconomic status
• IQ and other markers of mental health (verbal comprehension, reasoning, working
memory, processing speed) assessed at age 38
• IQ lower by 1.61 points for each 5 µg/dL increase in blood lead
• Other markers of mental health also lower for each 5 µg/dL increase in blood lead
Reuben A, Caspi A, Belsky DW, et al., 2017. Association of Childhood Blood Lead Levels With Cognitive Function and
Socioeconomic Status at Age 38 Years and With IQ Change and Socioeconomic Mobility Between Childhood and
Adulthood. JAMA. 2017;317(12):1244–1251. doi:10.1001/jama.2017.1712NZ Biological Monitoring Study
Objectives
1. To undertake a biological monitoring programme of selected substances
of concern (SoCs) in a cross-sectional survey of the New Zealand
population including adults and children;
2. To establish baseline levels of SoCs in the New Zealand population to
allow for future determination of temporal trends;
3. To compare the New Zealand SoCs levels with international levels;
4. To monitor the influence of gender, age, geographic region and
ethnicity in relation to the levels of SoCs in the New Zealand population;
5. To develop a robust methodology for adding or removing SoCs on a
national list;
6. To support the Protection Regulation and Assurance Business Unit deliver
its environmental and border health protection work programme in
relation to hazardous substances.NZ Biological Monitoring Study Whole blood Metals (lead, mercury, arsenic, cadmium, chromium, thallium, antimony) Urine Phenols (bisphenol A, triclosan, parabens, sunscreen active ingredients) Phthalates Cotinine (a metabolite of nicotine in humans) Fluoride Creatinine and specific gravity (for normalisation of whole blood/urine concentrations
NZ Biological Monitoring Study
Methodology
• Adults (age 19-64) randomly selected from the Electoral Roll (n=304)
• Children (age 5-18) recruited through schools and another study
(n=193)
• 15 minute questionnaire on lifestyle, housing, diet, occupation
• Ethical approval granted in May 2014
• Whole blood samples collected by private pathology laboratory
– Sample analysis of whole blood by ICP-MS (2017) with a LOD of
0.041 µg/LNZ Biological Monitoring Study
Results
• Geometric mean blood lead (BLL) 1.3 µg/dL (adults) and 0.8 µg/dL
(children)
– None of the participants exceeded 10 µg/dL notifiable level
• Determinants of BLL assessed using linear regression of log-
transformed BLL
– BLL positively associated with age and male gender
– Children BLL positively associated with shellfish consumption
– Adult BLL positively associated with age, alcohol consumption,
roof water supply, working in glass manufacturing
– BLL negatively associated with consumption of tofu and canned
foodMale
Female
BLL (ug/L)
AgeNew Zealand
USANZ Biological Monitoring Study
• Limitations
– Under 5’s not included
– Non-random selection of children
– Over 65’s not included
– Results may underestimate population BLLPolicy Implications
• Clearly blood lead has decreased since the 1980’s
– Removal of lead in petrol and paint
• MoH reports 105 notifications in 2017 (0.002% of the population)
• MoH is considering lowering notifiable blood lead to 5 µg/dL for all
age groups
– Consistent with Australia, USA, Canada
– There is evidence of effects on infants < 5 µg/dL
• Body burden of lead in infants is not known
• Body burden in the elderly is not known
– Release of lead through bone de-mineralisationThe “Prevention Paradox”
No. of Children Average IQ Estimated IQ
X =
in Distribution Loss Points Lost
Current 0.5 million 6.1
Reference Value 3.1 million
= 5 µg/dL
5.7 million
2.10 µg/dL 1.6
9.3 million
6.4 million
1.43 µg/dL 0.9
5.7 million
12.7 million
0.3
4.7 million
Estimated Loss of IQ in US Children at Different Levels of Blood Lead (µg/dL)
AAP Council on Environmental Health, 2016Recommendations
For Government and researchers
• Exposure to lead needs to be “re-framed” as a current problem
– The issue was not solved back in the 90’s
• Government agencies should continue to monitor lead in people
– Particularly in infants and the elderly
• Ongoing research into the health effects of low-level exposure to
lead
– How does lead compare to other developmental toxicants (e.g.
mercury, PFAS)?
– Lead toxicity is a classic example of a “known unknown”Recommendations
For the contaminated land and waste industries
• Costs associated with lead contamination can be high (e.g.
consenting, disposal, site management)
• We need:
– Better information on the relationship between soil lead and
indoor dust
– More guidance for councils and homeowners to assess the risk
posed by lead
– More communication between agencies (e.g. councils, central
government, industry groups)Final thoughts
“Each dollar invested in lead paint hazard control results in a return of
$17 – $221 or a net savings of $181 – $269 billion”
Gould, E., 2009. Environmental Health Perspectives
“Cost–benefit analyses show that vaccination against the most common
childhood diseases delivers large returns on investment, saving between
$5.30 and $16.50 in costs for every dollar spent on immunizations”
Zhou et al., 2005. Archives of Pediatrics and Adolescent Medicine
“Notre-Dame’s Toxic Fallout”
https://www.nytimes.com/interactive/2019/09/14/world/europe/notre-
dame-fire-lead.html?smid=nytcore-ios-shareQuestions? http://publichealth.massey.ac.nz/home/research/research- projects/biological-monitoring-study-of-selected-chemicals-of-concern/ Jonathan Coakley jcoakley@tonkintaylor.co.nz
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