Mercury Levels in an Urban Pregnant Population in Durham County, North Carolina

Marie Lynn Miranda,Pamela J Maxson,Sharon Edwards

doi:10.3390/ijerph8030698

Marie Lynn Miranda, Pamela J Maxson + Show 1 more

Open Access

https://doi.org/10.3390/ijerph8030698

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Abstract

The adverse effects of prenatal mercury exposure, most commonly resulting from maternal fish consumption, have been detected at very low exposure levels. The omega-3 fatty acids found in fish, however, have been shown to support fetal brain and vision development. Using data from a prospective, cohort study of pregnant women from an inland area in the US South, we sought to understand the fish consumption habits and associated mercury levels across subpopulations. Over 30% of women had at least 1 μg/L of mercury in their blood, and about 2% had blood mercury levels above the level of concern during pregnancy (≥3.5 μg/L). Mercury levels were higher among Asian/Pacific Islander, older, higher educated, and married women. Fish consumption from any source was reported by 2/3 of the women in our study, with older women more likely to consume fish. Despite eating more fish meals per week, lower income, lower educated women had lower blood mercury levels than higher income, higher educated women. This suggests the different demographic groups consume different types of fish. Encouraging increased fish consumption while minimizing mercury exposure requires careful crafting of a complex health message.

Highlights

Fetal exposure to mercury can result in adverse developmental effects and is most commonly due to maternal fish consumption [1]
Participants completing the study and for whom a valid blood mercury level was reported from Mayo Medical Laboratories were included in these analyses
The analyses presented in this paper were performed on data for women enrolled between study inception (June 2005) and December 2008 and delivered by the end of March 2009

Summary

Introduction

Fetal exposure to mercury can result in adverse developmental effects and is most commonly due to maternal fish consumption [1]. Consuming omega-3 fatty acids, which is associated with prenatal fish consumption, has positive effects on infant cognitive development [2,3,4,5]. These two contrasting considerations combine to present public health professionals and clinicians with the difficult task of delivering a complex environmental health message to women of childbearing age. Epidemiological birth cohort studies in the Faroe Islands indicate that prenatal mercury exposure leads to negative neurobehavioral effects in children, including reduced attention span, fine-motor function and verbal memory impairment [8,9], and mental and psychomotor retardation [10]. In a Polish study, prenatal maternal blood mercury levels greater than 0.50 g/L raised the risk of delayed performance in children compared to prenatal maternal mercury levels less than 0.50 g/L, with the risk for delayed performance increasing more than three-fold when cord blood mercury levels were greater than

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