Exposure Assessment of methyl mercury from consumption of fish

Overview

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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:

eter (HQ). The results showed that meHg levels of 67 species ranged from 0.013 to 0.252 mg/kg of wet weight (WW) with
significant differences between different fish and seafood groups (χ2KW = 49.09; p < 0.001). Median concentrations of meHg
in fish and seafood groups in descending orders are as follows: demersal fish (0.1006 mg/kg WW) > pelagic fish (0.0686 mg/
kg WW) > freshwater fish 0.045 mg/kg WW) > cephalopods (0.0405 mg/kg WW) crustaceans (0.0356 mg/kg WW). The
mated weekly intake (EWI) values showed results below 1.6 µg/kg BW/week, the tolerable levels recommended by the Joint
the consumption of crustaceans (0.3488 µg/kg BW/week or 21.8% of PTWI) and cephalopods (0.504 µg/kg BW/week or
31.5% of PTWI). The results from this study also revealed the HQ value for overall consumption of fish and seafood by the
McManus et al. 2011). lifetime which is set at 0.0001 mg/kg/day for Hg (Wan
ing between 95 and 97% of total mercury (THg) when the strated that THg or meHg concentrations were low when
health outcomes of neurologic damage such as mental retar- An earlier study also reported that 48% of marine fish had
ted proportion of meHg in seafood was set at 0.5 mg/kg hazardous to the populations in this region (Agusa et al
in Malaysian Food Regulation 1985 (Food Act 1983, (Act 2005, 2007). Anual et al. (2018) reported that 14% of sea-
In view of the above, the FAO/WHO Expert Committee study showed the EWI values ranging from 2.1 to 4.0 μg/kg
tolerable weekly intake (PTWI) for meHg at 1.6 µg/Kg/ population was exposed to 1182 g per week or 73.95% of
to over a lifetime without intolerable risk of health effects 145.8% of the PTWI (Hajeb and Jinap 2011). Instead, the
survey (von Stackelberg et al 2017) or involved a specific population consumption survey, which revealed that 16.2%
There are also studies that involved vulnerable groups of required in order to obtain a 95% confidence interval and
the median consumption at the 50th percentile. A potential the 24-h dietary diary forms and answering questions on the
using a Perkin Elmer Flow Injection Mercury System (FIMS) 1 × 1 0 –4 (mg/kg-day) by the USEPA (Risk Information
Malaysian Food Regulation 1985 (Food Act 1983, (Act 281), and of fishes (mg/kg wet weight); RfD is the oral reference
38, the level at 0.5 mg/kg meHg in fish and seafood. population group (55 to 62 kg for adult, 45 kg for ado-
analyzing the THg data, it was cleaned and examined for fish (p = 0.048). Median concentrations of meHg in fish and
egories and groups were keyed in using data from a dietary sal fish (0.1006 mg/kg WW) > pelagic fish (0.0686 mg/kg
survey. After completing the data entry, it was checked for WW) > freshwater fish 0.045 mg/kg WW) > cephalopods
any discrepancies, such as coding numbers, typo errors, and (0.0405 mg/kg WW) crustaceans (0.0356 mg/kg WW). The
normality using the one-sample Kolmogorov–Smirnov test, means of the percentage to THg at 93%, 81%, and 50% for
median consumption at the 50th percentile. all fish and seafood categories except for freshwater fish
(Table 2). Overall, the results revealed that the older popu-
THg and meHg (median ± IQR) concentrations in marine (95.8 ± 99.8 g/day). Nevertheless, the differences are signifi-
Table 1. MeHg levels of 67 fish and seafood species ranged the young adults (18 to 40 years old) (82.0 ± 89.1 g/day). In
fish, the median for meHg levels was higher (> 0.1 mg/ sumption by the older populations (p < 0.05).
Sarda orientalis) and eight species of demersal fish (Lut- ethnicities in Peninsular Malaysia were shown in Table 3.
pared to the marine fish at 0.045, 0.046, and 0.066 mg/kg compared to the other two ethnic groups. In the contrary,
Table 1 Total Hg and meHg (mg/kg WW) levels in fish/seafood from the LKIM Complexes and wholesale market in Peninsular Malaysia
Table 1 (continued)
WW, wet weight; conversion of DW mercury concentrations in fish samples to WW were by means formula: DW = WW × (100/100-MC).
Calculation of meHg concentrations were based on mean percentage of methylmercury to total mercury at 93% for fish, 81% for cephalopods
and 50% for crustaceans (Anual et al 2018)
Comparison of meHg levels between different fish/seafood groups: χ2KW = 49.090, p = 0.000, N = 405, Median = 0.061 ± 0.050 mg/kg WW
the other two groups. Table 5 showed consumption of fish shown in Table 6, and the EWI were expressed in micro-
Table 2 Freshwater fish and seafood consumption (g/day/person) (median ± IQR) by population in Peninsular Malaysia at different age catego-
Table 3 Freshwater fish and Food category Ethnicity #

Methods (brief)

respectively, indicating that long-term consumption of this Malaysia, with data collected through face-to-face inter-
consumption estimates based on representative populations The sample size was calculated using data from a Selangor
2015; Al-Mughairi et al 2013), collected from specific or two separate places (urban and rural), three different eth-
calculation of sample size, questionnaires, and interviews or meHg contamination levels in seafood with the con-
In a microwave digestion device, a dried sample was digested this study is the exposure through consumption of fish.
apparatus with a programmable sample dispenser and a cold System (IRIS) (USEPA 2000). The HQ meHg was esti-
vapor atomic absorption spectrometry (AAS) methodology, as mated using the equation below (Wan Azmi et al 2019):
reference samples. Details on the analysis were described else-
cury contents in fish samples to wet basis values, and the quantity the exposure frequency (350 days/year); ED is the dura-
normality using the one-sample Kolmogorov–Smirnov test, means of the percentage to THg at 93%, 81%, and 50% for
WW, wet weight; conversion of DW mercury concentrations in fish samples to WW were by means formula: DW = WW × (100/100-MC).
used to estimate meHg intakes for risk assessment data. In (Ahmad et al 2015b), and none of these samples surpassed
commonly consumed marine fish samples and other seafood and co-workers (Anual et al. 2018) for the nearest estima-
as well (cephalopods; 8 species and crustaceans; 12 species). tion, yet, only one sample each was analyzed for crustacean
The relationship between THg levels and size of samples (Metapenaeus affinis) and cephalopod (Loligo duvauceli).
sampled from fish and seafood at different habitats, family shown in Table 1. The results showed significant differences
only 1%, or three samples of demersal fish (bluespotted demersal fish, crustacean, and cephalopod (χ2KW = 49.090,
one sample exceeded the Malaysian and international guide- by in pelagic fish (0.0686 mg/kg WW), freshwater fish

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.

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