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The “Truth Fairy” Project: New Methods for Lead Exposure Analysis

Posted on August 9th, 2019

A pilot study in lead exposure highlights new analytical methods for assessing environmental health. Jill E. Johnston, a researcher at the University of Southern California, recently published the “Truth Fairy” Project, which studied lead and arsenic levels in shed baby teeth from children living in close proximity to a Los Angeles based lead-acid battery manufacturer with known environmental contamination.

Lead and Arsenic are common contaminants with high environmental significance. Any level of exposure is detrimental to human health, being linked to organ damage, and negative neurological and psychological impacts. Ambient levels of lead in New Jersey soils generally fall around 125-300 mg/kg, and ambient levels of arsenic in New Jersey soils generally fall around 5-15 mg/kg (NJDEP, 2003). While these concentrations are naturally common, exposure for humans at any amount is still unsafe, especially among developing children. New Jersey Soil Remediation Standards for lead ranges from 400-800 mg/kg, and arsenic is 19 mg/kg (based on these natural background values).

Johnston’s study, based in southern California, used laser-ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to analyze lead and arsenic concentrations in baby teeth donated from residents within two miles of a lead-acid battery manufacturer with known soil contamination and human exposure pathways. Prior to this study, lead and arsenic exposure was primarily measured through blood tests, which only reflect exposure within 4 weeks prior to testing. Shed deciduous teeth, however, reflect an entire lifetime of exposure as they incorporate elements from their environment into layers of dentin and enamel as they grow. After determining the neonatal line, or marker of pre-birth vs. post-birth development of tooth layers, Johnston compared prenatal and postnatal concentrations of lead to soil concentrations surrounding the battery factory where these children resided. Results revealed a statistically significant, positive correlation between both prenatal and postnatal concentrations of lead in teeth with increasing soil lead levels.

Johnston’s findings allow scientists to look further into the past and get a better feel for historic lead exposure and the effects it has on human health. With potential sources of lead constantly present in our own backyards, such as similar battery factories in New Jersey (Ridgewood, Paterson, and Ledgewood, for example), or lead based paint used in homes built before 1978, this insight is vital to improving our current understanding of lead exposure and has the potential to impact how we study this topic in the future.

The study: https://pubs.acs.org/doi/full/10.1021/acs.est.9b00429

Science in the news: https://cen.acs.org/environment/pollution/Baby-teeth-reveal-childrens-past/97/web/2019/05

NJDEP study on ambient levels of metals in soil: https://www.state.nj.us/dep/dsr/research/ambient-levels-metal.pdf


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