Heavy metals in Salted fish

This page draws on evidence from Morshdy et al. 2023, Hasselberg et al. 2020, aluminum (Al) Kharusi et al. 2026, and Robinson et al. 2025. The complete citation list is at the bottom of the page.

Species differences in salted fish

Salted fish is preserved with dry salt or brine, encompassing a wide range of traditional products including Egyptian feseikh (salted and fermented mullet), sahlia (salted keeled mullet), salted sardine, and salted smoked herrings, as well as dried salted tilapia and other small fish widely consumed across sub-Saharan Africa. These are traditional protein staples; in Egypt they are associated with specific festivals and in West Africa they are important dietary complements to starchy staples.

The available measurement evidence covers retail surveys of Egyptian salted fish (Morshdy et al. 2023) and processed small fish from Ghanaian markets (Hasselberg et al. 2020), supplemented by a broad Africa-wide study of dried fish nutrition and contaminant context (Robinson et al. 2025) and a clinical case report of mercury toxicity from dried shark in Oman (Al Kharusi et al. 2026).

The principal finding from the Egyptian retail survey (n=80 samples, 4 product types) is that lead and cadmium concentrations differ substantially by fish species. Herrings had the highest mean lead concentration (720 µg/kg wet weight), more than twice the EU maximum permissible level (MPL) of 300 µg/kg for fish muscle, and all 20 herring samples exceeded this limit. Feseikh and sahlia (mullet products) had intermediate lead levels (320 µg/kg), with 15-20% of samples above the MPL. Salted sardine had the lowest mean lead (190 µg/kg), and no sardine samples exceeded the MPL. The cadmium pattern followed the same rank order: herrings (90 µg/kg) exceeded the EU MPL (50 µg/kg) in 95% of samples; sardine (30 µg/kg) rarely exceeded it. Mercury concentrations were below 10 µg/kg in all types that contained detectable mercury, well below the EU MPL of 500 µg/kg, and was undetectable in the smoked herrings.

Total arsenic in Egyptian salted fish was high relative to other analytes, with feseikh reaching sample concentrations up to 1,530 µg/kg. No EU maximum exists for total arsenic in fish, and in marine fish the organic arsenobetaine form typically constitutes the majority of total arsenic; arsenobetaine is considered substantially less toxic than inorganic arsenic. The papers in this unit measured only total arsenic; arsenic speciation is absent from the evidence base.

From Ghana, salted tilapia showed lead, cadmium and mercury all below the limit of quantification, and a low total arsenic of approximately 100 µg/kg, suggesting that freshwater-farmed or freshwater-caught tilapia salted by local processors carries a markedly lower contamination burden than the fatty marine salted fish types documented in Egypt.

What counts as salted fish on this page

This page covers fish whose primary preservation method is salting, including products that combine salting with fermentation (feseikh) or salting with subsequent smoking (salted smoked herrings). The page does not cover canned or tinned fish, fresh or frozen fish, or pure smoked fish where salt plays only a minor role.

Traditional product categories covered by the evidence on this page:

• Feseikh (fesikh): traditional Egyptian salted and fermented Nile mullet (Mugil cephalus); strong-smelling fermented product
• Sahlia (salted keeled mullet): Egyptian salted flat-head grey mullet (Mugil capito)
• Salted sardine: Egyptian retail salted Mediterranean or Atlantic sardine (Sardina pilchardus or Sardinella species)
• Salted smoked herrings: Egyptian smoked herrings post-salting
• Salted tilapia: West African salted freshwater tilapia (Tilapia spp.) including farmed product

Dried shark and dried predatory fish are referenced briefly for mercury context but are more fully addressed on the shark ingredient page.

Heavy metal contamination profile

Typical-range values are means or mean ranges across product types from the Egypt retail survey (Morshdy 2023, n=80, wet weight). Tilapia data from Ghana (Hasselberg 2020) are whole dried product wet weight with 28% moisture; below-LOQ values indicate the contamination is at or below the detection threshold. p95 values are not calculable from the published mean and standard error data alone.

Lead

Lead concentrations in the Egyptian retail survey ranged from means of 190 µg/kg (salted sardine) to 720 µg/kg (herrings) on a wet weight basis, with individual sample concentrations not separately reported.¹ Percent of samples exceeding the EU MPL of 300 µg/kg: sardine 0%, feseikh 15%, sahlia 20%, herrings 100%. These Egyptian retail values are substantially above what Ghanaian salted tilapia showed (below LOQ, fresh-weight-equivalent approximately <82 µg/kg given moisture normalization).²

The wide species range in Egypt reflects food chain position and water body contamination: herrings and mullet (feseikh, sahlia) are larger or fattier fish occupying higher trophic positions than sardine, and they were sourced from Egyptian delta markets where aquatic lead burdens may be higher. The Zagazig survey does not distinguish between contamination from the fish’s lifetime accumulation and any contribution from the salting process itself; salt and salting tanks are plausible secondary sources for some metals.

Cadmium

Cadmium showed a similar rank order to lead: herrings highest (90 µg/kg), followed by feseikh (60 µg/kg), sahlia (50 µg/kg), and sardine (30 µg/kg).¹ The EU MPL for cadmium in fish muscle is 50 µg/kg; 95% of herrings samples, 55% of feseikh, and 40% of sahlia samples exceeded this in the Egyptian survey. Salted sardine rarely exceeded it (5%). Ghanaian salted tilapia: below LOQ.²

Cadmium accumulates more in the gills, liver and kidneys than in muscle; fish consumed whole (as is common for small species) carry more cadmium per gram than muscle-only portions. The Egyptian study analyzed muscle tissue, so the results are relevant to consumption of the edible flesh.

Total arsenic

Total arsenic in Egyptian salted fish was highest in feseikh (sample range 860-1,530 µg/kg), followed by sahlia (550-1,230 µg/kg), herrings (420-840 µg/kg) and sardine (160-390 µg/kg).¹ These are ranges across the 20 samples per type, not means. The paper reports that 90% of sardine samples and 100% of the other three types exceeded the total arsenic MPL it cites. However, no EU maximum level for total arsenic in fish has been established (the EU arsenic limit applies to other food categories, not fish muscle), and WHO/JECFA withdrew the PTWI for inorganic arsenic in fish in 2011 pending further evaluation.

Critically, the Morshdy 2023 study measured only total arsenic, not speciated arsenic. In marine fish the dominant arsenic form is arsenobetaine, an organic compound that is not absorbed and excreted unchanged, with a toxicological profile substantially less concerning than inorganic arsenic (iAs). Elevated total arsenic in marine fish therefore does not translate directly to elevated inorganic arsenic exposure. Without speciation data, interpreting these total arsenic values in a health risk context requires caution. The fermented feseikh product, in which the fish undergoes partial autolysis under salt for weeks to months, could plausibly alter arsenic speciation through enzymatic or microbial action, but this has not been measured in the available evidence.

Total mercury

Mercury was low in the Egyptian salted fish types: sahlia had the highest mean (6 µg/kg ww), followed by feseikh (3 µg/kg) and sardine (2 µg/kg). Mercury was not detected in salted smoked herrings, consistent with the well-established thermal volatility of mercury compounds at smoking temperatures.¹ All detected concentrations were below 10 µg/kg, far below the EU MPL of 500 µg/kg for fish. Ghanaian salted tilapia was also below the detection limit for mercury.²

Dried predatory fish, particularly shark, occupies a different risk category for mercury. Omani dried shark was measured at 0.63 mg/kg (630 µg/kg) wet weight by Al-Ghabshi et al. 2018 (Microbiological, chemical and nutritional quality and safety of salted cured fishery products from traditional dry fish processing plants in the Sultanate of Oman), exceeding the EU MPL of 500 µg/kg for most fish species. A published clinical case documents blood mercury exceeding twice the reference threshold (38.72 µg/L vs. reference <15 µg/L) in a patient with habitual daily dried shark consumption in Oman, normalizing after dietary cessation.³

Mercury in the included papers was measured as total mercury; methylmercury (the form of greatest concern for nervous system toxicity) was not measured or estimated separately.

Why salted fish accumulate heavy metals

Fish accumulate lead and cadmium from ambient water and from dietary prey over their lifetimes. Larger, longer-lived and fattier fish at higher trophic positions accumulate more of these metals from the food chain. The water quality and sediment contamination of the fish’s habitat is a primary external driver: coastal and delta regions adjacent to industrial or urban areas typically show higher metal burdens in locally caught fish than fish from open-ocean or less contaminated water bodies.

The salting and fermentation process itself does not remove heavy metals from fish tissue. Morshdy et al. 2023 and Abbas et al. 2021 (cited therein) note that salting has minimal effect on accumulated metals, consistent with the non-volatile, non-soluble behavior of lead (Pb), cadmium (Cd), and iAs in tissue.¹ Any concentration effect from moisture loss during salting (which can modestly reduce water content) would marginally increase per-kilogram metal concentrations, but Egyptian salted fish analyzed on a wet weight basis retains substantial moisture and comparisons to fresh fish MPLs are roughly valid.

Heat applied during the smoking step (applied to herrings after salting in the Egyptian products) can volatilize elemental and organic mercury, explaining the non-detection of mercury in smoked/salted herrings despite its presence in the other three types.¹ This is consistent with the broader literature on smoking effects on mercury: temperatures achievable in traditional smoking kilns (150-300 degrees Celsius) are sufficient to volatilize a significant fraction of organic mercury compounds.

Salt used in curing can carry trace metals if derived from industrial sources with impurities, but the salting-process contribution to the fish muscle burden has not been quantified in the included studies.

Concentration ranges

The clearest within-study comparison from the Egyptian retail data is species type:¹

Salted sardine had the lowest lead (190 µg/kg, below EU MPL of 300 µg/kg) and cadmium (30 µg/kg, below EU MPL of 50 µg/kg) in this survey. Herrings showed the highest lead and cadmium, both well above EU limits. This species effect is likely driven by trophic position (herrings being a fattier, higher-trophic fish than sardine) and the habitat of origin.

Across origins, Ghanaian salted tilapia (a freshwater farmed or wild-caught species) was below the LOQ for lead, cadmium, and mercury, suggesting substantially lower contamination than the Egyptian marine fatty fish types. This cross-study comparison must be interpreted cautiously because the analytical methods, moisture bases, and market contexts differ between the two surveys, and tilapia is a freshwater species from a different production system than Egyptian coastal marine fish.

A lower-contamination choice within the category is therefore: sardine or tilapia over herrings or mullet for lead and cadmium. This conclusion is drawn from two studies with different matrices and contexts; it is directionally supported but not established by a controlled within-study comparison across origins.

For total arsenic, sardine showed the lowest range (160-390 µg/kg) and feseikh the highest (860-1,530 µg/kg), but as noted above, the arsenic speciation is unknown and the high total arsenic in feseikh may predominantly reflect organic arsenobetaine rather than the more toxic inorganic arsenic species.

Ingredient-derivative risk

Salted fish is used as a whole ingredient in many dishes and also processed further into concentrated derivatives: fermented fish paste (shrimp paste, bagoong, belacan, padaek), fish sauce (nam pla, patis, nuoc mam), dried fish powder, and anchovy paste. These derivatives concentrate the fish protein through further moisture removal or enzymatic fermentation; to the extent the source fish carries heavy metals, those metals are carried forward and potentially concentrated in the derivative.

No heavy metal concentration data for derivative products (fish sauce, fish paste, dried fish powder) are available from the measurement studies included on this page. The included studies measured whole salted fish as consumed. Metal concentrations in derivatives would depend on: the contamination level of the source fish, the processing method and degree of reduction, and whether any step selectively removes or concentrates metals.

As a first-order approximation, a 10-fold moisture reduction (e.g., reducing fish paste to a concentrate) would increase per-kilogram metal concentrations proportionally, assuming metals remain in the matrix. For the Egyptian salted fish data, this would take herrings lead (720 µg/kg, already above the EU MPL) into a range of concern for derived concentrated products. Products made from lower-contamination sources (sardine, tilapia) would show lower absolute concentrations in the derivative as well.

For suppliers producing fish sauce or paste as a downstream product of salted fish, testing the finished product for Pb, Cd, and total mercury (tHg) is preferable to relying on source fish survey averages, since batch-to-batch species and origin variability means source-fish averages are a poor proxy for a specific lot’s derivative concentration.

Processing and preparation effects

Salting does not remove heavy metals from fish tissue, as noted above. The key processing variable affecting mercury specifically is heat from smoking: mercury was undetectable in the smoked/salted herrings but present in the unsmoked salted types (sardine, feseikh, sahlia). This suggests that high-temperature smoking can reduce but does not necessarily eliminate mercury exposure from salted fish.

Whether the fermentation process in feseikh (weeks of maturation under salt) affects metal bioavailability or speciation has not been measured in the included studies. Fermentation substantially changes the protein matrix and may alter the binding state of metals, but the net effect on exposure cannot be inferred from the available data.

Rinsing or soaking salted fish before consumption (a common practice to reduce saltiness) may modestly reduce surface-associated metals but would not affect metals bound in the fish muscle protein matrix. No quantitative data on this preparation step are available from the included studies.

Mitigation

The primary available mitigation lever for consumers of salted fish is species selection. Within the Egyptian retail categories measured by Morshdy et al. 2023, salted sardine had the lowest lead and cadmium, with no sardine samples exceeding EU regulatory limits for lead and only 5% exceeding the cadmium limit. Choosing sardine-based products over herrings or mullet products reduces lead exposure by approximately 3-4-fold and cadmium by approximately 2-3-fold based on the means in this survey.

For suppliers and producers, sourcing fish from water bodies with lower documented lead and cadmium burdens would reduce baseline contamination. However, the included studies do not provide origin-linked quality data for the Egyptian market products, so specific sourcing guidance by water body cannot be supported by the available evidence.

Dried predatory fish, particularly shark and large predatory species, should be treated as a separate high-mercury category and limited in frequency of consumption. The clinical case documented in Alkharusi et al. 2026 involved daily consumption; dietary modification reducing dried shark intake to a few times per week was associated with declining blood mercury levels and symptom resolution.³

Quantitative effects on lead and cadmium reduction from preparation steps (soaking, rinsing) are not established by the included studies. The effects in the table above reflect the comparative measurements or clinical observations available, not controlled intervention trials.

Regulatory limits

The principal applicable regulatory limits for heavy metals in fish and processed fish are:

EU cadmium species exceptions. EU Regulation 2023/915 sets a higher cadmium limit of 100 µg/kg for herring, mackerel, anchovy, sardine, swordfish, tuna, bonito, and sprat. The standard 50 µg/kg limit applies to all other fish muscle. This is relevant for the Egyptian survey: the herrings category showed cadmium means of 90 µg/kg, which falls below the species-specific 100 µg/kg limit for herrings rather than exceeding the general 50 µg/kg limit. The Morshdy 2023 paper cited the general 50 µg/kg limit throughout; under the species-specific limit, 95% of herring exceedance claims require re-evaluation.

Basis and processing. EU limits are stated on a wet weight basis and nominally apply to fish muscle meat. For dried or heavily salted fish with substantially reduced moisture content, applying fresh-fish wet-weight limits directly to dried product values overestimates exceedance. Hasselberg 2020 demonstrated that after normalization to 75% moisture (approximate fresh-fish moisture), all Ghanaian smoked fish values fell below EU limits despite appearing elevated on a dried-product weight basis.

Arsenic. No specific regulatory maximum exists for total arsenic or inorganic arsenic in fish muscle under EU, Codex, or FDA frameworks. The absence of a regulatory limit reflects the recognition that total arsenic in marine fish is dominated by non-toxic organic species (arsenobetaine) rather than toxic inorganic arsenic.

Testing

The primary analytical methods used in the measurement studies are:

• Egypt (Morshdy 2023): Atomic absorption spectrometry (AAS) with graphite furnace for Pb and Cd; hydride generation and cold vapor AAS for arsenic (As) and mercury (Hg). CRM: DORM-3 fish protein certified reference material (National Research Council of Canada). Recovery 90-105%. R² 0.980-0.999.¹
• Ghana (Hasselberg 2020): ICP-MS (iCapQ, ThermoFisher) with internal standards; NS-EN ISO/IEC 17025 accredited methods. LOQ values in Supplementary Reference 48 of that paper.²

For producers and QC purposes, ICP-MS provides multi-analyte capability covering all relevant metals in a single run. The key CRM for fish matrices is DORM-3 or successor materials (DORM-4) from the National Research Council of Canada. Wet acid digestion (microwave-assisted HNO3/H2O2) followed by ICP-MS is the standard approach for Pb, Cd, and total arsenic (tAs) in processed fish. Vapor generation (cold-vapor AAS or ICP-MS with mercury analyzer) is used for total mercury. For meaningful speciation (iAs vs organic As; methylmercury (MeHg) vs tHg), dedicated extraction and chromatography-coupled ICPMS methods are required; these are not reflected in the measurement studies included here.

Procurement

Based on the available evidence, the following purchasing considerations are supported by measurement data:

• Choose sardine over herrings or mullet for the lowest lead and cadmium within traditional Egyptian salted fish categories.
• Freshwater salted tilapia (as commonly found in West African markets) showed undetectable Pb, Cd and Hg, suggesting it is a lower-contamination choice compared to fatty marine salted fish, though the cross-study comparison should be interpreted with caution given differing analytical methods and product forms.
• Avoid daily consumption of dried shark or large predatory dried fish. These species carry substantially higher mercury than small non-predatory salted fish such as sardine or tilapia.
• Supplier quality documentation: for commercial buyers, requesting metals testing certificates for Pb, Cd, and tHg on the finished salted fish product against EU or Codex regulatory limits provides verification of the specific production lot rather than relying on category averages.

Specific origin guidance (e.g., which water body or country of origin produces lower-contamination Egyptian mullet) cannot be supported from the available evidence; the Zagazig survey did not link product to specific origins.

Exposure from salted fish

The Egyptian retail study computed estimated daily intakes (EDIs) based on Egyptian population salted fish consumption (48.57 g/day) and body weight (70 kg). Hazard quotients (HQ) and hazard index (HI) values were below 1.0 for all four product types and all four metals, indicating no apparent non-cancer health hazard under this consumption scenario.¹ The HI values ranged from 0.251 (salted sardine) to 0.868 (feseikh), with arsenic driving the largest individual HQ in the feseikh and sahlia categories.

These HQ/HI calculations used the computed EDI divided by US EPA reference doses and are specific to the Egyptian consumption scenario. Populations consuming salted fish more frequently or at higher quantities, or populations with other co-occurring metal exposures, would have proportionally higher hazard indices. The calculations used total arsenic rather than inorganic arsenic for the arsenic HQ, which likely overstates arsenic risk if organic arsenobetaine is the dominant species.

The clinical case of mercury toxicity from dried shark (Al Kharusi 2026) documents that daily habitual consumption of a high-mercury dried fish can produce blood mercury levels exceeding 2.5x the reference threshold, with resolution after cessation.³ This underlines that the low mercury values for common salted fish types are specific to those species; they do not apply to dried shark.

Evidence review and remaining gaps

This page rests on two measurement surveys, one clinical case report, and one nutritional study with partial contaminant data. The evidence base is thin by the standards of a fully synthesized ingredient page.

What is covered: Lead, cadmium, total arsenic, and total mercury in four Egyptian retail salted fish types (n=80, Morshdy 2023) and in Ghanaian salted tilapia (n=5 composite samples from one species, Hasselberg 2020). Clinical evidence for mercury exposure from dried shark (n=1 case, Alkharusi 2026). Broad nutritional and contaminant context for dried fish across Africa (Robinson 2025, contaminant data in SI appendix not fully extracted).

What is not yet measured in the evidence on this page:

• Inorganic arsenic (iAs): all arsenic is total arsenic; speciation is absent. This is the most significant analytical gap because the toxicological risk from total arsenic in marine fish is dominated by the organic species (arsenobetaine), not iAs.
• Methylmercury (MeHg): total mercury only; speciation absent.
• Nickel, aluminium, hexavalent chromium, tin: not measured in any included study.
• Other market regions: no measurement data for salted fish from South or Southeast Asian markets (where salt fish such as pla ra and bagoong are major dietary categories), from Mediterranean markets, or from Nordic salt fish traditions.
• Longitudinal or seasonal variation: single-survey cross-sectional data only.
• Production-chain sources: no data separating contributions from the fish’s lifetime accumulation vs. the salting process vs. the salt itself.

Arsenic speciation is the highest-priority analytical gap because total arsenic in some Egyptian types (particularly feseikh) is very high (up to 1,530 µg/kg) and the health risk interpretation depends entirely on the split between organic and inorganic forms.

Mercury speciation and predatory dried fish is the second priority gap, particularly for regions where dried shark or large predatory dried fish is a dietary staple. The Alghabshi 2018 Oman data and the Alkharusi 2026 clinical case establish that dried predatory fish can carry mercury at or above EU regulatory limits, but no MeHg speciation data are available from salted fish studies in this unit.

Salted fish FAQs

What heavy metals are found in salted fish? Lead, cadmium, total arsenic, and total mercury have all been measured in Egyptian retail salted fish. All four metals were detected in salted sardine, feseikh, and sahlia; mercury was not detected in smoked/salted herrings. Lead and cadmium concentrations varied widely by product type, with herrings showing the highest values and sardine the lowest.¹

Which type of salted fish has the lowest lead and cadmium? In the Egyptian retail survey, salted sardine had the lowest mean lead (190 µg/kg) and cadmium (30 µg/kg) of the four types tested. No sardine samples exceeded the EU regulatory limit for lead, and only 5% exceeded the cadmium limit. Salted tilapia from Ghana showed both metals below the limit of quantification in a separate study, suggesting it is also low for these analytes, though the two surveys are not directly comparable.^{1, 2}

Does the Egyptian feseikh have higher arsenic? Yes. Feseikh showed the highest total arsenic range in the Egyptian survey (860-1,530 µg/kg), compared to sardine (160-390 µg/kg). However, all arsenic measurements are for total arsenic. In marine fish, the dominant form is arsenobetaine, an organic compound that is essentially non-toxic and excreted unchanged. The fraction as toxic inorganic arsenic (iAs) has not been measured for these products. The high total arsenic in feseikh does not by itself establish high inorganic arsenic exposure.¹

Is mercury a significant concern in common salted fish? Not for the common types. Mercury concentrations in salted sardine, feseikh, and sahlia were 2-6 µg/kg wet weight, well below the EU maximum of 500 µg/kg. Dried predatory fish (shark, large tuna) are a different matter: Omani dried shark has been measured at 630-810 µg/kg, and a clinical case of mercury toxicity from daily dried shark consumption has been documented in Oman, with blood mercury normalizing only after dietary cessation.^{1, 3}

Does smoking salted fish affect mercury? Yes. Mercury was not detected in the salted smoked herrings in the Egyptian survey, while it was present (at low levels) in the unsmoked salted types. Heat from smoking is sufficient to volatilize a portion of mercury compounds. This applies specifically to mercury; smoking does not reduce lead, cadmium, or arsenic.¹

Why does salted fish contain these metals if it was fine before salting? The metals are present in the fish tissue before salting begins, accumulated from the aquatic environment during the fish’s lifetime. Salting does not introduce or remove them. Any moderate concentration effect from moisture loss during salting could marginally raise per-kilogram concentrations, but the dominant determinant is what the live fish accumulated from water and prey over its life.¹

How does contamination in salted fish compare between Egypt and Ghana? Salted tilapia from Ghanaian markets showed lead, cadmium, and mercury all below the limit of quantification, while Egyptian retail fatty salted fish (herrings, mullet) showed substantially higher concentrations for lead and cadmium. This likely reflects differences in species (fatty marine fish vs freshwater tilapia), trophic position, production system (wild vs farmed tilapia), and water quality in the fish’s habitat. It is a directional comparison across two different studies, not a controlled head-to-head survey.^{1, 2}

Is the arsenic in salted fish the same as the arsenic in rice? No. The form of arsenic in marine fish is predominantly arsenobetaine (organic), which is essentially non-toxic and excreted intact. The arsenic concern in rice is primarily inorganic arsenic (iAs), specifically arsenite and arsenate, which are substantially more toxic. Total arsenic in marine salted fish should not be compared directly to total arsenic in rice without speciation; the hazard profiles are different. Arsenic speciation has not been measured in the salted fish studies included here.¹

What percentage of Egyptian retail salted fish samples exceeded EU regulatory limits? In the Egyptian survey: for lead, 0% of sardine, 15% of feseikh, 20% of sahlia, and 100% of herrings samples exceeded the EU MPL of 300 µg/kg. For cadmium, 5% of sardine, 55% of feseikh, 40% of sahlia, and 95% of herrings samples exceeded the EU MPL of 50 µg/kg. No samples exceeded the EU mercury MPL (500 µg/kg). These are EU limits for fresh fish muscle; the Egyptian study compared its salted fish wet weight values directly to these limits without moisture adjustment.¹

Are the high total arsenic values in feseikh a health concern? Probably not primarily an inorganic arsenic concern, given that the dominant arsenic species in marine fish is arsenobetaine. However, without speciation data for feseikh specifically, the inorganic arsenic fraction cannot be excluded. The fermentation process in feseikh (weeks under salt) could theoretically affect arsenic speciation through microbial or enzymatic action, but this has not been studied. For precautionary purposes, limiting very high-frequency consumption of feseikh and testing total arsenic alongside iAs in production quality programs would be prudent.¹

References

Works cited in this page’s text, in first-appearance order.

1. Heavy metal contents in salted fish retailed in Egypt: Dietary intakes and health risk assessmentMorshdy AEMA et al. · Open Veterinary Journal · 2023 · DOI: 10.5455/OVJ.2023.v13.i12.22Peer-reviewed
2. Composition of nutrients, heavy metals, polycyclic aromatic hydrocarbons and microbiological quality in processed small indigenous fish species from GhanaHasselberg AE et al. · PLoS ONE · 2020 · DOI: 10.1371/journal.pone.0242086Peer-reviewed
3. Chronic Mercury Toxicity Associated With Habitual Dried Shark Consumption in Oman: A Case ReportAl Kharusi F et al. · Cureus · 2026 · DOI: 10.7759/cureus.116693Peer-reviewed (case report)
4. Dried fish provide widespread access to critical nutrients across AfricaRobinson JPW et al. · PNAS · 2025 · DOI: 10.1073/pnas.2426844122Peer-reviewed

Sources

Source records associated with this topic. Inclusion does not establish that every finding applies to this product or ingredient. References above identify works cited in the text.

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.

Update history

No substantive edit history is available in this build. The full commit record is available in git.