Comparing American and French Biomarkers of Toxicity

While we’ve known mercury to be a dangerous substance for years now, the nature of this element’s toxicity—at what levels it burdens the body, and in what ways—has been less well-known and acknowledged. Previous studies into mercury’s toxicity have uncovered some startling risks for adverse effects, but these findings have been met with relatively little concern given their association with autism and vaccines. That’s why researchers Janet Kern, David Geier, Francoise Ayzac, James Adams, Jyutika Mehta, and Mark Geier were interested in conducting additional research on mercury toxicity by comparing mercury body-burdens between neurotypical populations in Texas and France with urinary porphyrins, biomarkers that reveal the presence of mercury toxicity through specific patterns.

The Experiment

Unlike Kern et al.’s many previous studies on mercury toxicity, this study did not examine children with neurodevelopmental disorders; rather, the group’s sample population was comprised exclusively of neurotypical children. This was done to ensure that accurate results of toxic metal burden were obtained, given that there is some evidence to suggest that ASD children are less likely to excrete heavy metals and therefore maintain higher levels of toxicity in the body for inherent reasons.

To conduct the study, each day a subject’s first urine sample was collected and sent to a laboratory for a profile assessment of their urinary porphyrins. For practicality, these samples were collected by subjects’ parents via a collection kit with detailed instructions. Subject populations from both Texas and France included children that were between 2 and 13 years of age, had received routine childhood vaccinations, and did not qualify as maintaining any neurodevelopmental disorder as identified by the Childhood Autism Rating Scale.

After profiling the urinary porphyrins from both American and French sample subjects, Kern et al. employed statistical analysis, specifically the Wilcoxon matched-pairs sign-ranked test statistics, to produce an accurate comparison between corresponding ages and genders. The statistical analysis also accounted for differences in fish consumption, another way in which children are exposed to mercury.

The Findings

Given Kern and the Geiers’ previous research on vaccines and mercury, their results were not surprising. Statistical analysis of the two test subject groups revealed that children in the United States maintain much higher levels of urinary porphyrins associated with mercury body-burden than children in France. For example, increases were shown for the levels of urinary precoproporphyrins and total coproporphryins.


The disparity found between mercury body-burden in American and French test subject groups underscores the reality that increased environmental exposure to mercury does lead to increased body-burden of the toxic element. For example, the United States is the world’s leading producer of Hg emissions, as a result of its heavy dependence on coal-fired power plants, while France maintains a limited amount of coal reserves and emits far less mercury into the air. Additionally, the mercury-containing preservative Thimerosal was present in more than 30 routinely-administered childhood vaccines in the United States in 1999; in France, children were administered just 3 Thimerosal-containing vaccines. The United States also continued to advocate for the administration of Thimerosal-containing influenza vaccines to women, infants, and young children, even after Thimerosal was removed from other childhood vaccines. France, meanwhile, did not advocate vaccine administration to these groups.

Exposure to mercury also affects neurodevelopment and performance in more ways than many may realize; mercury doesn’t just target one specific cognitive function or area of the brain. Rather, exposure to mercury can disrupt at least a dozen of areas and functions of the brain, and these can trigger additional abnormalities and dysfunctions throughout the rest of the body. Such is why Kern et. al believe that more research must be conducted into the long-term effects of increased mercury body burden, and propose that studies that focus on longer experiments from sample populations in multiple locations be pursued.

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