An assessment of the cord blood:maternal blood methylmercury ratio: implications for risk assessment.

Abstract

In the current U.S. Environmental Protection Agency reference dose (RfD) for methylmercury, the one-compartment pharmacokinetic model is used to convert fetal cord blood mercury (Hg) concentration to a maternal intake dose. This requires a ratio relating cord blood Hg concentration to maternal blood Hg concentration. No formal analysis of either the central tendency or variability of this ratio has been done. This variability contributes to the overall variability in the dose estimate. A ratio of 1.0 is implicitly used in the model, but an uncertainty factor adjustment is applied to the central tendency estimate of dose to address variability in that estimate. Thus, incorporation of the cord:maternal ratio and its variability into the estimate of intake dose could result in a significant change in the value of the RfD. We analyzed studies providing data on the cord:maternal blood Hg ratio and conducted a Monte Carlo-based meta-analysis of 10 studies meeting all inclusion criteria to generate a comprehensive estimate of the central tendency and variability of the ratio. This analysis results in a recommended central tendency estimate of 1.7, a coefficient of variation of 0.56, and a 95th percentile of 3.4. By analogy to the impact of the similar hair:blood Hg ratio on the overall variability in the dose estimate, incorporation of the cord:maternal ratio may support a 3-fold uncertainty factor adjustment to the central tendency estimate of dose to account for pharmacokinetic variability. Whether the information generated in this analysis is sufficient to warrant a revision to the RfD will depend on the outcome of a comprehensive reanalysis of the entire one-compartment model. We are currently engaged in such an analysis.

Cited by papers we hold 8

• A State-of-the-Science Review of Mercury Biomarkers in Human Populations Worldwide between 2000 and 2018 · 2018
  No notice
• Evidence on the Human Health Effects of Low-Level Methylmercury Exposure · 2012
  No notice
• Relation between Cord Blood Mercury Levels and Early Child Development in a World Trade Center Cohort · 2008
  No notice
• Adult Women’s Blood Mercury Concentrations Vary Regionally in the United States: Association with Patterns of Fish Consumption (NHANES 1999–2004) · 2008
  No notice
• Dose–Response Relationship of Prenatal Mercury Exposure and IQ: An Integrative Analysis of Epidemiologic Data · 2007
  No notice
• A Biomonitoring Study of Lead, Cadmium, and Mercury in the Blood of New York City Adults · 2007
  No notice
• Public Health and Economic Consequences of Methyl Mercury Toxicity to the Developing Brain · 2005
  No notice
• Blood organic mercury and dietary mercury intake: National Health and Nutrition Examination Survey, 1999 and 2000. · 2004
  No notice

Reads

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.