Co-considering Selenium Concentrations Alters Mercury-Based Fish and Seafood Consumption Advice: A Data Compilation and Critical Assessment

Abstract

There has been persistent interest in the mediating role of the micronutrient selenium (Se) in mercury (Hg) toxicity since the 1960s. Despite many unresolved questions regarding Se− Hg interactions, considerable research has been performed to document Se:Hg molar ratios in aquatic animals as a basis for inferring the health risks associated with their consumption. We compiled the co-reported Se and Hg data for 386 shellfish, finfish, and aquatic mammals from 89 papers to assess differences in consumption safety categorizations according to health risk metrics that (a) consider Hg concentrations alone or (b) co-consider Se and Hg concentrations. Species-specific mean Hg concentrations for 23% of all data points in our database exceeded the FAO/ WHO maximum level, and 68% and 83% had estimated daily intake per meal values for adults and children above the Joint FAO/WHO Expert Committee on Food Additives Provisional Tolerable Daily Index. In contrast, only 12% of data points would be categorized as unsafe for consumption on the basis of their 1:1 Se:Hg molar ratios. Se-inclusive risk metrics reversed safety categorizations for a majority of high-trophic level species that are most likely to exceed Hg-based risk thresholds. Adopting Se-inclusive risk metrics has potentially significant implications for seafood consumer health and is likely premature.

Fisheries Volume 49 Number 8 August 2024

“…Given that a wide range of animal species are protected from Hg toxicity by a Se : Hg molar ratio >1:1, and that this phenomenon prevails over a broad range of environmental conditions, Se should be factored into Hg toxicity assessments for humans to avoid suppressing human consumption, and for wildlife to avoid undue alarm. Not only does excess Se protect fi sh from Hg toxicity, Se also protects the human and wildlife consumers of fi sh (Ujang and Perkins 2022 ;Zampetti and Brandt 2023 ). In addition, the benefi ts derived from consuming marine and most freshwater fi sh outweigh the potential damages of MeHg exposure from consumption of most fi sh (Hibbeln et al 2007 ;Oken et al 2008 ;Ralston et al 2019 ).…”

“…This indicates that sequestering of Se by high Hg levels, which prohibits selenoprotein production, is not a widespread regional phenomenon-despite the prevalence of fi sh consumption advisories for Hg alone (Stahl et al 2009(Stahl et al , 2023. Given the importance of including fi sh in a healthy diet (Ralston et al 2019 ;Zampetti and Brandt 2023 ), Se values must be factored into MeHg toxicity assessments when establishing fi sh consumption advisories to assess Hg toxicity potential more accurately.…”

Mercury Biogeochemistry and Biomagnification in the Mediterranean Sea: Current Knowledge and Future Prospects in the Context of Climate Change

“…Unfortunately, molecular interactions between the two elements are not yet fully understood, and the protection of Se against long-term exposure to Hg remains to be definitely proven [98]. For this reason, in a very recent review of the available data on Hg in seafood and the potential risks to consumer health, Zampetti and Barndt [99] concluded that approaches to consumer safety based on the 1:1 (Se:Hg) molar ratio are likely premature.…”

An updated review of the salient geomedical aspects of mercury for enhancement of data quality in simulation modelling and other prognostic applications: Africa case descriptions

“…Mercury is a chalcophile element (having affinity for a sulphide phase) and extremely active biologically. A complex relationship exists between Hg and Se (also primarily chalcophilic in character) with reference to toxicity effects (Zampetti and Brandt, 2023), with co-exposure leading to reduced toxicity (antagonism; See, e,g., Oliveira et al, 2017;Tinggi and Perkins, 2022), enhanced toxicity (synergism), or no effect at all (See: Wyatt et al, 2016). Different interactions may be related to chemical speciation, concentration, and method of administration (Dang and Wang, 2011); but these have not been thoroughly studied.…”