HAIR MERCURY ISOTOPES, A NONINVASIVE BIOMARKER FOR

Overview

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Key numbers

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• and MeHg in the third trimester), Table S1 (all studies reporting hair Hg isotopes), Table S2 (quality assurance/quality control), Table
• S3 (farmer/non-farmer comparison of biomarkers), Table S4 (with/without Hg isotopes comparison of characteristics), Table S5 (with/
• without Hg isotopes comparison of biomarkers), Tables S6–S21 (four sets of sensitivity analyses), Table S22 (Spearman’s correlation
• for continuous maternal characteristics), Table S23 (Associations for categorical maternal characteristics), legend for Dataset S1 and
• mothers in China (n=265). Associations between mass dependent fractionation (MDF) (δ202Hg)
• correlated with hair Hg, which explained 27–29% of the variability in hair δ202Hg.
• small sample sizes (n=5–45) (Table S1).9–18 Two main findings have been reported. First,
• study, Hg isotopes were analyzed in 244 additional maternal hair samples (n=265/398,
• 67%). For most mothers, maternal hair samples corresponded to exposures during the
• second trimester (n=252/265, 95%). Due to limited mass of second trimester hair, Hg
• isotopes for 13 mothers (5%) were analyzed in hair samples corresponding to exposures
• established values (Table S2; Supporting Information, and Dataset S1).
• control and quality assurance criteria (Table S2). The average recoveries for standard
• reference materials and matrix spikes ranged from 78–98%, and the average relative
• standard deviation for replicate analyses ranged from 4.2–8.4% (Table S2).
• between Δ199Hg and %MeHg intake from rice (Model B).10,15 Percent MeHg intake from
• intake (kcal), maternal proportion of calories (%) from protein, log10 maternal hair THg,
• mean from multiple imputation based on the multivariate normal distribution37, conditional
• non-farmer) correlated with rice/fish ingestion (Table S3). Lastly, as a sensitivity analysis,
• Maternal age averaged (± 1 standard deviation) 28 ± 5.7 years (range: 17–45 years), 78% of
• mothers did not complete high school, and 87% of mothers identified as Zhuang ethnicity
• (Table S4). Among participating mothers, fewer parents were farmers (76%) compared
• to non-participating mothers (85%) (Chi-squared test, p=0.02). Moreover, the total energy
• respectively) (Table S5). Lastly, there were no participating mothers who smoked during
• rice was 82%, while the median %MeHg intake from fish was 18% (Table S5). Most
• The median MeHg intake from rice (0.43 μg/day) was 2.5 times higher than the median
• MeHg intake from fish (0.17 μg/day) (Table S5).
• THg concentration was 0.47 μg/g (range: 0.13, 1.8 μg/g) (Tables S1 and S5).
• The median values (range) for hair δ202Hg, Δ199Hg, and Δ201Hg were 0.44‰ (range:
• respectively (Table S1). The range between minimum/maximum values for hair δ202Hg was
• 2.69‰, while the ranges for hair Δ199Hg and Δ201Hg were narrower (0.81‰ and 0.65‰,
• isotopes were reported (Fig. 1 and Table S1)9–14, 16–18, the median values for δ202Hg,
• consumption (Tables 1–4). In Models A and B, in the unadjusted models, hair Δ199Hg was
• did not ingest fish (Beta: 0.082‰, 95% CI: 0.024‰, 0.14‰), and negatively associated with
• %MeHg intake from rice (Beta: −0.00060‰, 95% CI: −0.0011‰, −0.00011‰). However,
• these associations were attenuated after covariate adjustment (Tables 1–2).
• MeHg intake (Beta: −0.038‰, 95% CI: −0.075‰, −0.00098‰) (Table 3), and positively
• associated with serum omega-3 fatty acids (Beta: 0.27‰, 95% CI: 0.14‰, 0.39‰) (Table
• hair THg (Fig. 2b), and whether one or both parents were farmers (Table 1–4). The
• ingestion (Tables 1–4). In all four models, hair δ202Hg was strongly, negatively associated
• with hair THg (Fig. 2a), and positively associated with maternal age (Tables 1–4).
• Among non-farmers (n=62) (Tables S6–S9), hair Δ199Hg was positively associated with

Methods (brief)

• Methods.—Mercury (Hg) stable isotopes were analyzed in hair samples from peripartum
• small sample sizes (n=5–45) (Table S1).9–18 Two main findings have been reported. First,
• While mothers were in the hospital, a maternal hair sample (~50 strands) was collected for
• once it emerges from the scalp. At the same time, a maternal blood sample was collected for
• study, Hg isotopes were analyzed in 244 additional maternal hair samples (n=265/398,
• 67%). For most mothers, maternal hair samples corresponded to exposures during the
• isotopes for 13 mothers (5%) were analyzed in hair samples corresponding to exposures
• in the second trimester plus the first or third trimesters. In addition, 15 hair samples were
• Plus multicollector-inductively coupled plasma-mass spectrometer (MC-ICP-MS, Thermo
• δ202Hg( ‰ ) = ((δ202Hg/δ198Hg)sample /(δ202Hg/δ198Hg)NIST 3133 − 1) × 1000
• A secondary standard (UM-Almadén) was run every five samples to ensure accuracy
• imputed data; (2) including hair samples corresponding to exposures during the second
• trimester only; 3) excluding 21 hair samples previously measured15; and 4) excluding
• Hair samples corresponded to exposures mainly during the second trimester; the median hair
• respectively). The photochemical slope between Δ199Hg and Δ201Hg in hair samples was
• (Fig. 1b) but similar to the slope associated with rice samples (slope=1.11).15 Hair Δ199Hg
• a negative association in the main analysis. Consistent with the small sample size, it was
• hair samples previously analyzed (Tables S18–S21).15 Similar results were observed as in

Implications

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Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Shellfish (shrimp, crab, lobster, clams, oysters, mussels)
• Mercury
• Mercury

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Update history

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