Mercury Concentration in Breast Milk and Infant Exposure

Overview

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Key numbers

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mean THg levels ranged from <0.76 to 22.7 ng/mL during Infant exposure . Brazil
the period, and the mean level for all samples (n0142) was
for 77.8 % of samples. Mothers consumed mostly food from mortality rates (2) and the chance of developing diabetes,
correlation was also found between vegetable consumption been exposed, mainly from dietary sources (6).
tilapia (up to 0.03 μg/kg (11)) and in sea catfish (Cathorops born at term (38–41 weeks of gestation), and at least a high
kg (12)). At least 90 % of THg found in fish was present as heights were measured at the residence according to the
MeHg of 1.6 μg/kg BW for women of child-bearing age and value was estimated by adding the weight at birth to the
a PTWI for THg of 5 μg/kg BW were established by the mean weight gain for the period obtained for the other
mostly within the range of 0.5 to 7 ng/mL (22–26). Factors breastfeeding. The participants were instructed to wash both
primiparous, exclusively breastfeeding, with a healthy infant UK) using a 2 % stannous chloride solution as a reduction
digested and analyzed. A 1,000 mg/L mercury standard
dard curves in water in the range of 0.01 to 0.2 μg/L (five correlation tests between variables, and the significance
(10×B+3 sd) was 0.26 ng/mL and LOQ (10×B+8 sd) Mercury Levels in Human Milk and Infant Exposure
Participants of the study responded to a 24-h dietary recall the first 3 months of life (Table 1). Half the infants were
75th day, a 200-g portion of ready-to-eat salmon (359 kcal, <LOQ to 22.7 ng/mL, and the mean level for all samples
and 1.9 mg DHA) was given to each mother to be consumed mL). Figure 1 shows the box plot of the data and the mean
rection was applied to the data of the 74th and 76th days. ity of mercury levels among the mothers (initial mean log
questionnaire (FFQ) was applied on the 90th day postpar- icant smooth increase (initial mean log mercury level of
fish consumption frequency. Discrete values for the frequen- Table 1 Maternal and infant characteristics
Mercury intakes for each infant were calculated for the 30th, Infant, 50 % male
(5 μg/kg BW or 7.1 μg/kg BW/day) and expressed as 90 days (n013) 1,261±73 1,053–1,300
There was a significant correlation between maternal Dietary information is shown in Table 2. The mothers most-
correlation was found between infant weight at any time and vegetable consumption and THg (p00.015). Carbohydrate,
(>100 %) at least once during the period. Seven infants that one mother consumed no fish during the entire period of
had intakes exceeding the PTWI at the 30th, 60th, and the study, eight mothers (47 %) consumed fish at least once
Table 2 Usual food group con-
meals with fish per month. Two mothers consumed fish postpartum milk (0.64±1.46 μg/L). In Sweden, Björnberg
one to two meals per week containing fish. The mean daily cantly between 4 days (0.06–2.1 μg/L) and 6 weeks postpar-
fish consumption frequency was 0.1, with no correlation tum (0.07–0.37 μg/L), but remained unchanged thereafter
with THg levels in breast milk (Table 2). (up to 13 weeks).
Austria (1.59 ± 1.21 μg/L (22)), Spain (0.45–0.62 μg/L found a significant positive correlation between breast milk
(26)), Slovenia (mean of 0.3 ng/g, median of 0.2 ng/g THg and the consumption of grain, fat, and vegetable
(34)), Turkey (3.42±1.66 μg/L (25)), and Saudi Arabia groups (but not with the fruit group). There was also a
(3.1±4.0 μg/L (23)). The higher THg levels found in Brazil significant positive correlation with carbohydrate intake.
(8, 9). About 50 % of the THg levels in breast milk were als, grains, and vegetables are mainly between 1 and 6 μg/
al. (34) found these to be, on average, 38 % (P1003 %, staple food in Brazil, was shown to be present as MeHg in
P90070 %), a much lower rate than found in mothers’ hair China (42). Gundacker et al. (22) found that mothers with
(89 %) and in cord blood (94 %). lower body weights (<60 kg) had significantly higher breast
in colostrums (mean of 1.37±2.14 μg/L) than in 60-day (salmon) intervention (74–90th day), a significant increase
several associations between postnatal MeHg biomarkers shown that there has been a 30 % increase in the amount
Planinsek P, Osredkar J, Horvat M (2011) Biomarkers of low- of toxic elements due to consumption of vegetables, fruits, meat,

Methods (brief)

Abstract Breast milk samples collected from 18 nursing 0.015 and 0.045, respectively). No correlation was found
the period, and the mean level for all samples (n0142) was
for 77.8 % of samples. Mothers consumed mostly food from mortality rates (2) and the chance of developing diabetes,
and carbohydrate intake and THg levels in the samples (p0 Mercury is a neurotoxic element widely present in the
intake is linked to lower risk of coronary heart disease and to Breast Milk Samples
lactation (19, 20). However, exposure of the mother to Breast milk samples (approx. 2 mL) were collected on the
dence, active/passive smoking, anemia, and diet (22, collecting the samples. Samples were kept frozen in the
25–27). In most studies, milk samples were collected from mother’s home freezer and transported in thermal boxes to
of mercury present in breast milk samples collected over a Each mother was asked to annotate the time spent breast-
90-day period from nursing mothers in a low fish-eating feeding for each sample collection point. The volume con-
The study population was a sub-sample from a previous
milk samples of mothers who received a fish portion for Prior to analysis, the samples were defrosted at ambient
consumption and who were enrolled in an exercise protocol. temperature, and the two samples collected from each moth-
ics in Brasilia, Brazil, in 2002 and 2005 during their pre- nized. A 1-mL aliquot of the homogenized milk sample was
mothers who agreed to donate milk samples according to the duced into a Microwave DGT-100 (Provecto Systems, Bra-
project’s protocol (over a 90-day lactation period, eight zil) for digestion. The digest was transferred to a 25-mL
agent. Duplicate aliquots of each homogenized sample were Statistical Analysis
of variation of 9.9 %. The limits of detection (LOD) and

Implications

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised