Selenium Differentially Influences Methylmercury Retention across

Overview

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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:

• previous studies have shown that Hg and Se concentrations in 100 water with continuous aeration and a range of
• retention versus loss has important implications for its least 48 h. We selected this concentration range to span an
• Se. (10−100 ppb).38 Diatoms accumulated an average of 4 ± 2 ng
• (2) Does the effect of Se on MeHg bioaccumulation in replaced the slides when >50% of the diatom slides had been
• (10 ppm; Brooks Rand). Note that we analyzed samples for capsule to the posterior abdomen, which we defined as mayfly
• We conducted the mayfly experiment at seven aqueous control measurements were within 5% of the value.
• and high (2 ng MeHg/L) MeHg treatments. We selected this analysis in new 125 mL PETG bottles and acidified to 0.4%
• freshwater bodies (∼0−60 μg/L total Se),45 with SeMet for MeHg concentration using aqueous ethylation with sodium
• et al.,12 we used concentrations of SeMet below 3.2 μg total 1630).47 All standard recoveries were within 15% of accepted
• pre-emergent nymph (PEN), subimago, and imago. We MS. All standard recoveries were within 10% of accepted
• mayflies in 30% nitric acid at 60°C overnight. We analyzed cumulative life history transfer factor (LHTF): imago MeHg
• 1630). Standard recoveries were 97.8 ± 1.0% (mean ± SE) for cessation of eating and egestion of MeHg contaminated
• certified reference materials (n = 27; IAEA407: fish diatoms or excretion of internalized MeHg prior to
• homogenate; IAEA452: scallops), 98.0 ± 1.8% for liquid metamorphosis. It is important to recognize that concen-
• calibration standards (n = 12), and 102.4 ± 2.1% for matrix trations in PEN can be higher than larvae (which would
• spikes (n = 6). Duplicate relative percent differences were 1.7 indicate a gain rather than elimination) owing to proportional
• ± 0.5 (n = 7). Digest blanks were 0.023 ± 0.022 pg MeHg (n differences in body mass loss relative to elimination during this
• = 12), and reagent blanks were 0.104 ± 0.012 pg MeHg (n = life transition. We modeled each transfer factor using linear
• dietary MeHg treatments (p = 0.00018, F(1,26)=19.1; (mayfly and high MeHg dietary treatments, and are provided in Table
• concentrations (elimination transfer factor >1; mean = 1.1 ± between life stages associated with Se exposure − rather than
• concentrations. Points are composite values (six to 18 mayflies) by Se exposure concentration. Error bars show 95% confidence intervals. Linear
• S1). Additional table showing the predicted aqueous Invertebrates: Will Proposed Thresholds for Toxicity to Fish and
• equals 1 (Table S1) (PDF) 1766−1770.

Methods (brief)

• (10 ppm; Brooks Rand). Note that we analyzed samples for capsule to the posterior abdomen, which we defined as mayfly
• SeMet exposure levels for each of the low (0.2 ng MeHg/L) Chemical Analyses. We collected water samples for MeHg
• environment, from natural to mountaintop mine-impacted stored them at 4°C until analysis. We analyzed water samples
• representing an unknown fraction of the total Se. Our goal was tetraethylborate, purge and trap, and cold vapor atomic
• to measure the interaction between SeMet and MeHg across fluorescence spectrometry (CVAFS) paired with inductively
• the broadest range possible. Based on data reported in Gerson coupled plasma mass spectrometry (ICP-MS; EPA Method
• Measured aqueous Se concentrations were 0.22, 0.53, 0.64, We collected water samples for TSe by filtering the water
• within 14 aquaria (9.46 L tank with 4 L of water). then storing the sample at −18 °C until analysis. We analyzed
• We sampled mayflies at four life stages: late instar larvae, water samples for TSe with a PerkinElmer Elan DRCII ICP-
• stage were collected on the same date, as growth rates differed
• We collected six to 18 mayflies from each life stage in glass compared to late instar larvae; (2) metamorphic transfer
• We measured all collected mayflies for length. We used compared transfer factors between low and high dietary MeHg
• Friedman, S. L.; Hallinger, K. K.; Monroe, A. P.; White, A. E. The 543−554.
• Inhibit Larval Mayfly Growth and Development. Environ. Toxicol. Aqueous Ethylation, Purge and Trap, and Cold Vapor Atomic

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

• Shellfish (shrimp, crab, lobster, clams, oysters, mussels)
• teething-and-snacks
• Mercury
• Mercury
• Cadmium

Verification notes

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Update history

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