Synthesis of maternal transfer of mercury in birds: Implications for altered toxicity risk

Environmental Science & Technology
By: , and 



Maternal transfer is the predominant route of methylmercury (MeHg) exposure to offspring. We reviewed and synthesized published and unpublished data on maternal transfer of MeHg in birds. Using paired samples of females’ blood (n=564) and their eggs (n=1814) from 26 bird species in 6 taxonomic orders, we conducted a meta-analysis to evaluate whether maternal transfer of MeHg to eggs differed among species and caused differential toxicity risk to embryos. Total mercury (THg) concentrations in eggs increased with maternal blood THg concentrations; however, the proportion of THg transferred from females to their eggs differed among bird taxa and with maternal THg exposure. Specifically, a smaller proportion of maternal THg was transferred to eggs with increasing female THg concentrations. Additionally, the proportion of THg that was transferred to eggs at the same maternal blood THg concentration differed among taxonomic orders, with waterfowl (Anseriformes) transferring up to 382% more THg into their eggs than songbirds (Passeriformes). We provide equations to predict THg concentrations in eggs using female blood THg concentrations, and vice versa, which may help translate toxicity benchmarks across tissues and life stages. Our results indicate that toxicity risk of MeHg can vary among bird taxa due to differences in the maternal transfer of MeHg to offspring.
Publication type Article
Publication Subtype Journal Article
Title Synthesis of maternal transfer of mercury in birds: Implications for altered toxicity risk
Series title Environmental Science & Technology
DOI 10.1021/acs.est.9b06119
Volume 54
Issue 5
Year Published 2019
Language English
Publisher ACS
Contributing office(s) Western Ecological Research Center
Description 14 p.
First page 2878
Last page 2891
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