Fish consumption and bioindicators of inorganic mercury exposure
Date
2006
Journal Title
Journal ISSN
Volume Title
Publisher
Université du Québec à Montréal, Montréal, QC, CA
Abstract
Background: The direct and close relationship between fish consumption and blood and hair
mercury (Hg) levels is well known, but the influence of fish consumption on inorganic
mercury in blood (B-IHg) and in urine (U-Hg) is unclear.
Objective: Examine the relationship between fish consumption, total, inorganic and organic
blood Hg levels and urinary Hg concentration. Methods: A cross-sectional study was carried
out on 171 persons from 7 riparian communities on the Tapajós River (Brazilian Amazon),
with no history of inorganic Hg exposure from occupation or dental amalgams. During the
rising water season in 2004, participants responded to a dietary survey, based on a seven-day
recall of fish and fruit consumption frequency, and socio-demographic information was
recorded. Blood and urine samples were collected. Total, organic and inorganic Hg in blood
as well as U-Hg were determined by Atomic Absorption Spectrometry. Results: On average,
participants consumed 7.4 fish meals/week and 8.8 fruits/week. Blood total Hg averaged
38.6 ± 21.7 μg/L, and the average percentage of B-IHg was 13.8%. Average organic Hg
(MeHg) was 33.6 ± 19.4 μg/L, B-IHg was 5.0 ± 2.6 μg/L, while average U-Hg was 7.5 ± 6.9
μg/L, with 19.9% of participants presenting U-Hg levels above 10 μg/L. B-IHg was highly
significantly related to the number of meals of carnivorous fish, but no relation was observed
with non-carnivorous fish; it was negatively related to fruit consumption, increased with age,
was higher among those who were born in the Tapajós region, and varied with community.
U-Hg was also significantly related to carnivorous but not non-carnivorous fish consumption,
showed a tendency towards a negative relation with fruit consumption, was higher among
men compared to women and higher among those born in the region. U-Hg was strongly
related to I-Hg, blood methyl Hg (B-MeHg) and blood total Hg (B-THg). The Odds Ratio
(OR) for U-Hg above 10μg/L for those who ate > 4 carnivorous fish meals/week was 4.00
[1.83 – 9.20].
Conclusion: This study adds further evidence to a positive relation between fish consumption
and IHg in both blood and urine, which may result from absorption of IHg from fish or from
demethylation of MeHg. The findings support the importance of assessing IHg exposure in
fish-eating communities. Further studies should examine the potential toxicity of IHg in
heavy fish consumers.
Description
In ARCHIV 126838
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IDRC Final Report
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