Exploring mercury and selenium dynamics in Amazonian

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

• Plasma blood (arithmetic mean = 183 ± 78 μg Se.L−1) and plasma (AM = 103 ± 34 μg Se.L−1). Hg content in blood
• ing 80% of the dietary protein source (Hacon et al., 2020).
• al., 2021). Epidemiological studies that report median blood Hg levels
• fish-eating populations, such as Canadians (median of 199 μg.L−1) and
• Americans (median of 189 μg.L−1), as reported in cross-sectional stud-
• HNO3 and 0.005% v/v of Triton X-100), plasma samples were diluted
• 1:20 (250 μL plasma +4.75 mL of 0.5% v/v HNO3 and 0.005% v/v of
• urine + 9.5 mL of 0.5% v/v HNO3 containing 0.005% v/v of Triton X-
• equipped with a triple cone interface, operating with high-purity argon levels. After applying a paired t-test (99% confidence level), no statisti-
• (99,999%, Air Liquide, Sao Paulo, Brazil). Sample introduction system cally significant differences were observed between the paired sample
• ies reported mean Hg concentrations of 49 ± 36 μg.L−1 in blood (from
• General descriptive statistics (arithmetic mean, standard deviation, a n = 91 individuals) and 7.1 ± 6.6 μg.L−1 in plasma (n = 108) for
• median, and ranges), Kruskal–Wallis test followed by Dunn’s post hoc communities along the Tapajós River (Carneiro et al., 2014; Grotto et
• sumption frequency. Graphs were plotted and statistical analyses were mean blood Hg levels ranging from 3 to 7 μg.L−1 (n = 554) in 21 com-
• from 0.2 to 139 μg.L−1 in blood, 0.2–27 μg.L−1 in plasma, and up to about 34% of Hg content in whole blood. Our results indicate a similar
• 19 μg.L−1 in urine (Fig. 2, Table 1). The average Hg concentrations in
• PR proportion of 28%, which is still almost six times higher than the safety
• porting an average of 7.5 μg.L−1 (range of 0.2–36 μg.L−1, n = 171). levels do not necessarily point to Hg toxicity. Furthermore, the majority
• of participants in the current study (∼94%) had Hg whole blood levels
• dian blood Hg concentration was 9 μg.L−1 (Basu et al., 2018). Mean- In contrast to Hg trends, Se contents appeared relatively homoge-
• dividuals across three countries, median Hg levels were 15 μg Hg.L−1 in
• 0.4 μg.L−1, n = 1734), the USA (BloodP50: 0.79 μg.L−1, n = 5030; in plasma (ranging 11–351) indicate a downward trend of Se concentra-
• UrineP50: 0.24 μg.L−1, n = 1813), Canada (BloodP50: 0.65 μg.L−1, tions compared with median values in previous studies of Lemire et al.
• (BloodP50: 0.65 μg.L−1, n = 302; UrineP50: 0.91 μg.L−1, n = 234), and 135 μg.L−1 in plasma (ranging 54–913).
• Slovenia (BloodP50: 1.2 μg.L−1, n = 1085; UrineP50: 0.45 μg.L−1, Biomonitoring surveys have documented typical Se levels in blood
• n = 1020) (Basu et al., 2018). Despite the downtrend observed in the and plasma among adult worldwide populations (Jain and Choi, 2015;
• Tapajós and Amazon River regions, Hg blood levels of this population al., 2017; Tinggi and Perkins, 2022). In Brazil, the geometric mean Se
• observed in Australia (GM: 141, 118–224 μg.L−1 – CI 95%), Slovenia ditional dishes made from seal and whales (Hansen et al., 2004).
• United States (GM: 146.8, 144.1–247 μg.L−1 – CI 95%) (Tinggi and 3.3. Correlations of Hg and Se levels across biological matrices
• study ranged from 34 to 840 μg.L−1, with an arithmetic mean of Relation between Hg levels in plasma and blood (Fig. 3 and S.4) re-
• ported in other Amazon populations, such as Puerto Nariño in the (r = 0.83, p < 0.0001). A mean plasma/blood Hg concentration ratio
• Colombian Amazon, where a mean of 85 μg.L−1 (60–118 μg.L−1) was of 0.2 ± 0.1 was determined, corroborating with previous findings in
• mean blood Se values of 488, 225 and 191 μg.L−1 have been reported in
• viduals (1.65%), in almost all studied communities.
• method. The results (Table S1) remained consistent to the previously ues were observed in plasma and urine, with medians of 71 (9.2–1274)
• ity throughout the region (Basta et al., 2021). In the current study, 7%
• The median Se:Hg molar ratio in blood was 21, ranging from 3.5 to
• participants (0.45%) reporting that they never consume fish. A total of
• intake, such as Maripá (where 88% individuals are consuming fish daily of fish consumption. To improve the knowledge on this field, further re-
• centrations (27.7 μg.L−1). Surucuá, as example, had the highest median lation employing Se and Hg speciation and omics strategies, such as
• concentration (45.5 μg.L−1) with 61% individuals reporting frequent proteomics and metabolomics. It may elucidate the interaction between
• median (9.8 μg.L−1) and number of frequent consumers (25%), shared fectively involved in the genesis of Hg toxic effects, from those that bind

Methods (brief)

• Brazilian amazon pled plasma mass spectrometry (ICP-MS), in blood, plasma, and urine, of 1089 adult individuals from communi-
• ingly, Nunavimmiut Inuits exhibit high whole blood selenium levels 2.2. Sample collection
• persist in our knowledge about exposures worldwide, largely due to the Blood samples (6 mL) were collected as non-fasting samples in trace
• investigation which aims to apply the innovative concept of exposome samples exhibiting hemolysis were excluded from analysis.
• procedures for the collection. Spot urine samples were packed in a ster-
• ile container, hermetically sealed, from which 10 mL subsamples were
• transferred into conical tubes (Corning®). All samples were transferred
• Samples were prepared according to Batista et al. (2009). Briefly,
• blood samples were diluted 1:50 (40 μL blood + 1.96 mL of 0.5% v/v
• HNO3 and 0.005% v/v of Triton X-100), plasma samples were diluted
• Triton X-100), and urine samples were diluted at 1:20 (0.5 mL
• 2.3. Transport and storage of samples
• The transportation and storage of samples adhered to the protocols
• recommended by Sabé et al. (2000). Samples were processed on-site
• Technologies (NIST 955d, 1598a and 2670a). Reference samples were
• analyzed before and after ten ordinary samples. All results were within
• Total Hg and Se concentrations in samples were determined by In- and transportation, we analyzed a second replicate fraction of 50 sam-
• ductively Coupled Plasma-Mass Spectrometry (ICP-MS), according to ples. These samples were collected in the same evacuated tube, frac-

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Mercury
• Mercury
• Cadmium
• Lead
• Arsenic
• Nickel
• Tin

Verification notes

• Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
• Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
• Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
• Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
• HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

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.