Overview
Twenty months after a 300,000 m³ mine-tailing spill (January 2013) discharged into El Comedero (EC) dam in Sinaloa, Mexico, this study measured total Hg and Se concentrations in muscle, liver, gills, and guts of three fish species to evaluate cleaning-operation effectiveness and human health risk. High Se concentrations were found in the liver of all species (carp: 1.2 ± 0.4 µg/g ww; tilapia: 3.9 ± 2.1; bass: 3.5 ± 1.1), while Hg in liver was highest in blue tilapia (0.15 ± 0.11 µg/g ww). Tilapia (benthic-detritivorous) showed highest Se overall; largemouth bass had highest muscle Hg. Compared with measurements taken 3 months after the spill during a mortality event, liver Se and Hg had decreased by 7.2x and 4.7x respectively, indicating partial recovery but persistent Hg contamination. Applying Mexican consumption scenarios, non-cancer risk from Hg or Se via muscle consumption did not exceed thresholds.
Key numbers
- Three fish species: common carp (Cyprinus carpio, omnivore), blue tilapia (Oreochromis aureus, benthic-detritivorous), largemouth bass (Micropterus salmoides, piscivore)
- Tissues analyzed: muscle, liver, gills, guts
- Liver Se (µg/g ww): carp 1.2 ± 0.4; tilapia 3.9 ± 2.1; bass 3.5 ± 1.1
- Liver Hg (µg/g ww): tilapia highest at 0.15 ± 0.11; carp and bass lower
- Muscle Hg: highest in largemouth bass (piscivore, higher trophic level)
- Liver Se reduced 7.2x vs. 3-month post-spill; liver Hg reduced 4.7x vs. 3-month post-spill
- Non-cancer risk HQ < 1 for muscle consumption under Mexican consumption scenarios
- Journal: Environmental Science and Pollution Research
Methods (brief)
Cold vapor atomic absorption spectrometry (CV-AAS) for Hg; hydride generation AAS or ICP for Se. Tissues: muscle, liver, gills, guts. Post-mine-tailing-spill scenario with cleaning-operation effectiveness assessment. Mexico, Gulf of California ecoregion.
Implications
Certification: Mine-adjacent freshwater fish retain Hg at above-background levels 20 months post-spill; sourcing provenance matters for freshwater fish certification. Courses: Illustrative case study for mine-tailing impacts on freshwater food fish and the timeline of heavy metal recovery. App: Freshwater fish from mining regions carry elevated Hg risk; provenance flags warranted. Microbiome: Not applicable.
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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.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |