Concentration of Total Mercury in Convenience Fish

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

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:

1.1 ng g–1), and in the other convenience fish products ‘Fish bites’ and ‘Battered mince portions’ it was in the range of 48–64 ng g–1.
In ‘ready to eat’ deep-fried fish, the concentrations of Hg varied in a much wider range (from 55 to 306 ng g–1). To estimate the
cook products without time-consuming preparation. This has that sea fish contains more than 90 % up to 100 % of total Hg as
includes accuracy, linearity, and limit of detection (LOD). MESS-3, Marine sediment (National Research Council of
be conditional one, and a product content be uncertain. Four fish Hg concentration of 360 ng g–1 in fish for a mean sample mass of
weighed on analytical balance in the range of 250–300 mg. The Due to the absence of fish or fish products that could be used as
were transported by air stream into an analytical cell, heated equation: LOD = (a + 3 Sa)/b, where Sa is the standard deviation
high-frequency Zeeman correction system. In the process of was found to be 0.32 ng. With a mean sample mass of 250 mg, the
analysis, the software of Mercury Analyzer 915+ displays a curve relative LOD is 1.3 ng g–1. This value is below the lowest concen-
dard and certified reference materials, which cover the whole and found values 283 ± 25 ng g–1, n = 6.
1515, Apple leaves was found to be 45 ± 6 ng g–1 (n = 35). The other kind of convenience fish products ‘Fish bites’ and
1. Results and Discussion tion, in the range 48–64 ng g–1, n = 13. The Hg concentrations fit
3.1. Results of Hg Determination in Convenience Fish products, the value of relative standard deviation (RSD %) of Hg
Products and Fish determination was found to be in the range 4.2–13.6 %. Concen-
cook’ convenience fish products and ‘ready to eat’ deep-fried to be at a ‘trace’ level of 2.6 ± 0.33 ng g–1, n = 3.
fish cooked in a store, are presented in Table 1. There are data on Limit of detection of Hg determination, equal to the value of
Table 1 Hg content in convenience fish products, ‘ready to eat’ fish, and calculated safe amounts of weekly consumption for a person of 60 kg of body
30 Deep-fried snoek samples, 219 ± 19 – 0.192 Deep-fried in a vegetable oil, ready
found to be approximately 1.0 ng g–1. The other value of LOD mately 20 %.19
Table 1) was found to be 1.2 ng g–1. These two values of LOD are The authors are grateful to the National Research Foundation
close to the value of 1.3 ng g–1 estimated LOD through the regres- of South Africa for financial support of this work, Grant Number
55–93 ng g–1, n = 4) correspond to moderate Hg concentrations in ORCID iD
of this analysis was in the range 1.0–16 %.
Table 1), the consumption of deep-fried snoek should be limited http://www.atsdr.cdc.gov/spl/
amount for consumption (Table 1) could be increased or reduced World Health Organization), Safety Evaluation of Certain Food Additives
found to be 55.7 ± 3.8 ng g–1 (n = 37) for a whole fish with weights eases, Geneva, Switzerland.
from 0.6 to 2.8 kg, relative standard deviation was 6.8 %. The 10 US-EPA (United States Environmental Protection Agency), 1997,
boiling sunflower oil by 19 % and by preparation over burning Environmental Protection Agency, Washington, DC. Available at:
coal up to 26 %.19
acceptable mercury intake from fish in Taiwan, Chemosphere, 2007, 67,

Methods (brief)

analysis for mercury (Hg) content in South Africa. A Zeeman Mercury Analyzer was used for direct determination of Hg in these
products after thermal decomposition of samples followed by atomic absorption detection. The Hg concentrations in conve-
Convenience fish products, cooked fish, total mercury, mercury analyzer.
mulate, is less known.2 The organic form of mercury – methyl- this study was to analyze samples of convenience fish products
exposure to Hg through fish consumption, national and interna- A Model RA-915+ Zeeman Mercury analyzer (Lumex, St.
US Food and Drug Administration set a level of 0.5 µg g–1 of Hg measurements. This is a mercury analyzer for the determina-
MeHg in herbivorous fish and 1.0 µg g–1 for predatory fish (wet tion of total mercury in solid samples using the method of
weight).6 For a vulnerable group of the population that included thermal decomposition of samples and atomic absorption detec-
pregnant and breast-feeding women and the population that tion, described in EPA Method 74735.13 The Mercury analyzer
Consumers of ‘ready to eat’ cooked fish should be better a sample is determined from a calibration graph, plotted as
tent in fish is the most important factor to assess. Recommenda- Hg (ng). Real-time measurement of Hg released from a sample is
- To whom correspondence should be addressed. E-mail: panichevn@tut.ac.za mercury analyzer is the use of a thermal decomposition method
for releasing Hg from analyzed samples instead of their chemical range of possible Hg concentrations in analyzed samples. The
reduces chemical waste, prevents Hg losses and sample contam- of Standards and Technology, US Department of Commerce),
includes accuracy, linearity, and limit of detection (LOD). MESS-3, Marine sediment (National Research Council of
2.2. Samples The result of calibration shows that under similar operating con-
Samples used in this research were the following convenience ditions, standards with different matrices generate signals with
• Battered mince portions; results confirm that calibration of mercury analyzer, based on

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

Verification notes

Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

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
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised