MERCURY SPECIATION IN FISH TISSUE AND METHYLMERCURY RISK ASSESSMENT FOR

Overview

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Key numbers

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• tissue (HgTot) and consider an adjustment factor of 90% to estimate MeHg contribu-
• proportion in fish tissue worldwide varies widely (from 19% to 100%), with a global
• median of 82.3% (n = 50 published studies, including our results), significantly lower
• than the 90% adjustment factor commonly used. Cathorops fuertii shows a high mercury
• content, reaching up to 0.70 μg/g HgTot, with 78.9% as MeHg. Risk assessment reveals
• del 90 % para estimar la proporción de MeHg. Este estudio combina espectrometría de
• varía significativamente (19-100 %), con una mediana global de 82.3 % (basada en 50
• estudios), significativamente menor que el factor de ajuste del 90 %. La especie Cathorops
• cuales 78.9 % corresponde a MeHg. La evaluación de riesgo revela un valor considerable
• estimating the percentage of MeHg by assuming a 90% daily (Amos et al. 2022), serving 22 million people
• used as input to assess human health risk. Recently 82% of the fish managed in Mexico are wild-caught,
• (Kennedy et al. 2025) estimated methylmercury con- while 18% come from aquaculture. In 2018, the total
• tamination in Mediterranean seafood using this 90% seafood volume caught for human consumption was
• main objective, using a 90% adjustment factor leads (Caranx caninus) with 25 308 t, catfish or mexican
• %H= *100 (1) were adapted and validated using blank matrix and
• The solutions were diluted to the mark with 2% HNO3 loop and an analytical column Hypersil Gold C18 (150
• containing 25 ppb of indium and rhenium (In-Re) as mm × 4.6 mm, 5μm Hypersil GoldTM Thermo Scien-
• internal standards and 500 ppb of gold to chelate the tific, USA). The outlet of the chromatographic column
• Quality control and quality assurance were con- the HPLC. The mobile phase was composed of 30%
• points with concentrations equivalent to the middle 0.06 M of ammonium acetate, and 0.1% mercapto-
• µg/g was 103.98% ± 10.3, while the average recovery fish tissue was prepared periodically and used for peak
• for the NIST® SRM® 1946 was 93% ± 8.5. A duplicate identification and separation in the HPLC, as well as for
• obtaining a relative standard deviation (RSD) < 20%. of the extraction method and the speciation analysis
• HPLC-ICP-MS and to assess the human health risk 2025). The limit of detection (LOD) and the limit of
• associated with the MeHg obtained. The procedure quantification (LOQ) were calculated using 10 replicate
• proposed by Reyes et al. (2009) and the analytical measurements of blank matrix containing no detectable
• LOD = 3 x σ′0 LOQ = kQ x σ′0 al. 2018, Murillo-Cisneros et al. 2021) were reviewed.
• %R = × 100 involuntary ingestion. The HQMeHg was calculated
• Where: σ is the standard deviation and X with bar 0.0001 mg/kg-day and the ADDMeHg was calculated
• (HgTot) obtained from Q-ICP-MS and the speciated viewed data MeHg was estimated as 82% of HgTot; IR
• concentrations is 90%. Reported values of HgTot and
• Inzunza et al. 2011, Grosbois 2013, Basu et al. 2014, Table I shows the values of HgTot dry weight
• species (% H), and the values of HgTot wet weight above the MLP2. Although normativity does not
• the lowest average HgTot concentration (0.25 µg/g ± the 90% as MeHg (EFSA 2012, Murillo-Cisneros
• s 0.38 0.09 a range of HgTot values of 0.57 to 1.43 µg/g in retail
• were above the MPL3, as well as 50% of the values
• the Alaska Department of Health (Hamade 2014). The box in the chart represents the interquartile range (25 to 75th percentile),
• 25% of the values reported for Sonora. However, it HPLC-ICP-MS validation
• concentrations was 1 to 25 µg/L, with an acceptance LIQUID CHROMATOGRAPHY.
• criterion of R2 > 0.995. Table II shows the validation
• percentages, and % RSD for spiked matrix for Hg LOD 0.05 0.06 0.01 0.01
• and MeHg. After validation, the methodology was LOQ 0.48 0.79 0.10 0.05

Methods (brief)

• HUMAN HEALTH: VALIDATION THROUGH HPLC-ICP-MS. A STUDY FROM THE SEAFOOD
• HPLC-ICP-MS. El caso de la central de abasto de pescados y mariscos de la Ciudad de México
• plasma mass spectrometry (Q-ICP-MS) and high-performance liquid chromatography
• (HPLC) to quantify HgTot and MeHg in three high-consumption fish species from the
• We recommend adopting HPLC-ICP-MS to replace HgTot-based estimations, in line
• masas de cuadrupolo con plasma inductivamente acoplado (Q-ICP-MS) y cromatografía
• de líquidos de alta eficiencia (HPLC) para cuantificar simultáneamente HgTot y MeHg
• Los autores recomiendan implementar HPLC-ICP-MS para reemplazar las estimaciones
• mercury concentrations in fish tissue have been Sample collection and preparation
• (HgIn) and the methylated concentration of mercury (CONAPESCA 2018). Nine samples and three dupli-
• (MeHg) via speciation by liquid chromatography cates were collected from different sale points, each
• coupled with mass spectrometry (HPLC-ICP-MS) in weighing 500 g (wet weight). Three species were
• muscle samples of three highly consumed fish species evaluated: Caranx caninus, Cathorops fuerthii, and
• in Mexico obtained from the Seafood Central Market Sphyranea ensis. The samples were placed on ice
• proposed by the Environmental Protection Agency and frozen in the laboratory at –18 ºC. Each sample
• tion groups: women of reproductive age (16 to 30 The fish muscle samples were freeze-dried at the
• modeled for the Mexican territory with reported total weight of the dry sample (P2) was recorded, and the
• The freeze-dried samples were ground using a then used to determine the methylmercury con-

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

• Canned seafood (with tin flag)
• Fish — marine, predatory (tuna, swordfish, shark, king mackerel)
• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Shellfish (shrimp, crab, lobster, clams, oysters, mussels)
• Mercury
• Mercury

Verification notes

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Update history

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