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:
- 18th International
- Particulate matter (PM) has the potential to affect human and ecosystem health (IPCC, 2013). Finer fractions
- of PM can penetrate into lungs and are closely linked with toxic effects (Schlesinger et al., 2006). For
- human activities), contributing to PM and adding to the potential for human exposure (Wang et al., 2013;
- Zahran et al., 2013). Bioaccessibility may be defined as the availability of an element for absorption when
- dissolved in vitro in a body fluid e.g. gastrointestinal or lung fluids (Ellickson et al., 2001; Guney et al.,
- 2016). In vitro lung bioaccessibility tests are used to assess the bioavailability of metal compounds in
- et al., 2003). Two synthetic lung fluid solutions are commonly used: Gamble’s solution (GS) being
- (Zoitos et al., 1997). Lung bioaccessibility studies on PM from geological samples are limited (see the
- critical review of Guney et al., (2016)), and a few studies demonstrated a high potential for metals lung
- bioaccessibility in PM. The present study aims to (1) characterize contaminated soils (n=6) and mine tailings
- samples (n=3) for As, Cu, Fe, Mn, Ni, Pb, and Zn content; and, (2) to assess elemental lung bioaccessibility
- a set of micromesh sieves of 75, 50, and 20 µm openings and a vibrational shaker (Retsch AS-200). Samples
- were then characterized for their metal content both as received and in <20 µm fraction via acid digestion.
- The in vitro tests were conducted on selected samples (n=7) by using GS and ALF (see Colombo et al.
- (2008) for chemical compositions) inside an incubator at 37 °C using an orbital shaker at 100 rpm.
- Solid:solution ratio was 1:100 and an initial test time of 2 h was followed by repeated sampling of extracts
- at 6 h, 1 d, 3 d, 1 w, and 2 w. The analyses for potentially toxic elements were performed via AAS (Perkin-
- Elmer A200) and by ICP-OES (Varian Vista). For each contaminant, total and bioaccessible concentrations
- (mg.kg-1) as well as bioaccessible fractions (%) were determined. For QA/QC, procedure blanks were used,
- analyses were made in duplicate, a certified reference material was tested (BGS 102 for total and
- elevated in bulk samples, particularly for As (up to 2,040 mg.kg-1), Fe (up to 30.7%), Mn (up to 4,360 mg.kg-
- ), and Zn (up to 4,060 mg.kg-1). Furthermore, total concentrations in PM20 were almost always higher than
- in the original samples (e.g. As up to 3,940 mg.kg-1, Fe up to 41.6%, Mn up to 5,210 mg.kg-1, and Zn up to
- 3,230 mg.kg-1). Finally, contamination in mine tailings (S7-S9) were higher than in soil samples (S1-S6).
- Proceedings the1818 International
- This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
- 18th International Conference on Heavy Metals in the Environment
- most elements (e.g. As, Cu, Fe, Ni, Pb, and Zn for S1; all seven elements for S7). The difference can be
- explained by the difference in chemical compositions of GS and ALF, with ALF having a pH of 4.5, which
- e.g. 1,730 mg.kg-1 after 2 weeks (43.9%) for As in PM20 for S8, 1.33×105 mg.kg-1 (44.1%) for Fe for S3,
- and 728 mg,kg-1 (80.8%) for Pb for S7. Elevated bioaccessible concentrations as well as percentages of As,
- Bioaccessibility and test duration: The calculated solubilisation rates of elements were higher at 2 h, and
- around or below 1 mg.kg-1.h-1 after 6 h - 1 d. However, Fe was soluble at around 100 mg.kg-1.h-1 even after
- 1 d, which could be explained by its very high total concentrations in samples. At this stage, it is not possible
- recommended as tests conducted on PM20 using ALF indicated more conservative lung bioaccessibility
- (mg.kg-1) especially for As, Fe, Mn, Pb, and Zn after 2 w of testing of various samples indicate potential
- concerns in case of human exposure. Additional research is recommended (1) on the bioaccessibility of
- metals in additional various samples from geological samples as existing studies are limited, (2) on the
- standardization of in vitro lung bioaccessibility tests, and (3) on the characterization of human health risks
- Colombo, C., Monhemius, A.J., Plant, J.A. (2008). Platinum, palladium and rhodium release from vehicle exhaust
- catalysts and road dust exposed to simulated lung fluids. Ecotox. Environ. Safe., 71, 722-730.
Methods (brief)
- OBTAINED FROM GEOLOGICAL SAMPLES
- (Zoitos et al., 1997). Lung bioaccessibility studies on PM from geological samples are limited (see the
- samples (n=3) for As, Cu, Fe, Mn, Ni, Pb, and Zn content; and, (2) to assess elemental lung bioaccessibility
- Soils (samples S1-S6) and mine tailings (S7-S9) were repeatedly sieved to obtain PM20 (d<20 µm) by using
- a set of micromesh sieves of 75, 50, and 20 µm openings and a vibrational shaker (Retsch AS-200). Samples
- were then characterized for their metal content both as received and in <20 µm fraction via acid digestion.
- The in vitro tests were conducted on selected samples (n=7) by using GS and ALF (see Colombo et al.
- at 6 h, 1 d, 3 d, 1 w, and 2 w. The analyses for potentially toxic elements were performed via AAS (Perkin-
- Elmer A200) and by ICP-OES (Varian Vista). For each contaminant, total and bioaccessible concentrations
- bioaccessible concentrations), and some bioaccessibility tests were conducted with spiked samples.
- Contamination in samples: Total concentrations of potentially toxic elements in soils and mine tailings were
- elevated in bulk samples, particularly for As (up to 2,040 mg.kg-1), Fe (up to 30.7%), Mn (up to 4,360 mg.kg-
- in the original samples (e.g. As up to 3,940 mg.kg-1, Fe up to 41.6%, Mn up to 5,210 mg.kg-1, and Zn up to
- 3,230 mg.kg-1). Finally, contamination in mine tailings (S7-S9) were higher than in soil samples (S1-S6).
- Comparison of tests with ALF and GS: For all elements and all samples, tests with ALF yielded higher
- concentrations and percentages were elevated in numerous samples, especially for As, Fe, Mn, Pb, and Zn:
- 1 d, which could be explained by its very high total concentrations in samples. At this stage, it is not possible
- to recommend a fixed testing time as the exact behavior was highly element- and sample-specific.
Implications
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Verification notes
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Update history
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