Exposure in a Free-Living Generalist Rodent, Apodemus

Overview

This source page is a mechanical bulk-ingest record for a PDF in the methylmercury infant-formula research pull. 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:

• Environmental Science and Technology, 2019, 53 (10), pp.5977-5986. ⟨10.1021/acs.est.8b07194⟩. ⟨hal-02316627⟩
• HAL Id: hal-02316627
• https://hal.science/hal-02316627v1
• 2 metal exposure in a free-living generalist rodent,
• 4 Shinji Ozaki*†, Clémentine Fritsch†, Benoit Valot†, Frédéric Mora‡, Thierry Cornier§, Renaud
• 6 † Laboratoire Chrono-environnement, UMR 6249 CNRS/Université Bourgogne Franche-Comté
• 8 ‡ Conservatoire Botanique National de Franche-Comté, Observatoire Régional des Invertébrés, 7
• 10 § Centre régional de phytosociologie agréé Conservatoire Botanique National de Bailleul,
• 14 Food identification; Metabarcoding; Trophic transfer; Wildlife; Salicaceae.
• 19 Exposure of terrestrial mammals to chemical contaminants like trace metals (TMs) is considered
• 20 to be mainly based on trophic transfer. Although relationships between TM transfer to animals
• 22 respect to diet diversity has been poorly documented. In this study, the oral exposure to TMs of
• 23 wood mice Apodemus sylvaticus was investigated with respect to both the number of different
• 25 stomach content, i.e. diet composition. The results showed that consuming Salicaceae, a known
• 26 cadmium accumulator plant family, significantly increased exposure to cadmium and zinc.
• 27 However, an increase in diet richness minimized exposure to cadmium when mice consumed
• 28 Salicaceae items. This strongly suggests that TM accumulator items can lead to a high oral
• 32 TMs in generalist animals, which matches the predictions of the “diet dilution hypothesis”.
• 34 Trace metals (TMs) are naturally occurring substances in trace amounts, in a proportion below
• 35 0.1%, in natural media.1 Although some of them are essential for life, TMs can pose risks to both
• 36 wildlife and human health at elevated concentrations resulting from anthropogenic activities.2
• 37 The assessment and the mitigation of environmental risk of TM contamination of ecosystems
• 39 organisms to TMs. The exposure of wild mammals to TMs occurs mainly through consumption
• 40 of contaminated food.3 The composition of diet has been focused on as an important aspect of
• 41 the variation of exposure of small mammals to TMs. For instance, earthworms or snails,
• 42 organisms that may accumulate TMs at high concentrations in their tissues, have been considered
• 43 to be important contributors for exposure to TMs in mammals consuming them.4–6 However,
• 44 mammals can consume simultaneously numerous different items. Although ingesting some metal
• 45 accumulator items leads to an increase in exposure, many other less TM accumulator items could
• 46 reduce total TM concentrations in the diet. A wide variety of items consumed may result in two
• 47 opposite effects: increased opportunity of consuming TM accumulators or reduced TM
• 48 concentrations of ingested food. However, few studies have assessed the accurate diet
• 49 composition and richness related to the TM contamination in mammals,7 and, to our knowledge,
• 50 no study have investigated the relationships between the oral exposure of mammals to TMs and
• 52 The accurate determination of items actually consumed is a major challenge in wildlife diet
• 53 assessment because identification at high taxonomic resolution is almost impossible with
• 54 classical macro- or microscopy-based methods. However, current technological development
• 55 such as high-throughput next generation sequencing has led a rise of new DNA-based techniques
• 56 as a powerful approach for multispecies identification using degraded DNA extracted from wide
• 57 range of environmental samples, i.e. soil, water or feces (eDNA metabarcoding).8–12 The
• 58 efficiency of the eDNA metabarcoding has been demonstrated in diet analysis in various
• 59 mammals.13–17 This method is expected to identify in detail the diet composed of numerous items

Methods (brief)

• 57 range of environmental samples, i.e. soil, water or feces (eDNA metabarcoding).8–12 The
• 86 Sample Collection. Rodent Trapping. Wood mice were captured in spring (April) and in
• 108 obtaining constant mass. The dried samples were digested in HNO3 (67-69 %; Fisher Scientific
• 110 (SCP Sciences). The samples were then diluted by adding ultra-pure water (18.2 MΩ/cm2). TM
• 111 concentrations were measured with an inductively coupled plasma mass spectrometry (ICP-MS:
• 128 performed per each sample. For the amplification of arthropod and mollusc DNA, 2 µM of a
• 133 water (18.2 MΩ/cm2) to bring each sample to the final volume. The mixture was denatured at
• 137 order to monitor potential contamination. After amplification, the samples were purified using a
• 140 pooled in equal volumes, to achieve an expected sequencing depth of 10,000 reads per sample.
• 149 sequence), only unique sequences with a minimum count of 10 (sum of all samples) were used
• 212 among samples. We therefore assumed that changes in the biomass of a hyper-accumulator
• 473 sample size, and median of the classification group is mentioned below.
• 613 Sample Size of Wood Mice Used to Biomonitor Metals. Sci. Total Environ. 2006, 366 (2–
• 679 Creer, S.; Bista, I.; Lodge, D. M.; de Vere, N.; Pfrender, M. E.; Bernatchez, L.
• 766 with in Vitro Digestion/Caco-2 Cell Model. J. Med. Assoc. Thai. 2011, 94 (2), 164–171.

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)
• Shellfish (shrimp, crab, lobster, clams, oysters, mussels)
• Cadmium
• Lead
• Nickel
• Aluminum
• 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

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