Arsenic in Chinese Crayfish: Speciation Analysis, Cooking-

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:

60 samples revealed total arsenic (tAs) concentrations ranging from 53.6 to 419.9 µg/kg,
with a mean of 109.3 µg/kg. Arsenic occurred predominantly as low-toxicity organic
species, with arsenobetaine accounting for 41.3% of tAs on average, while inorganic arsenic
(iAs) constituted only 11.6% (mean 12.5 µg/kg). Evaluation of common cooking methods
by 28.2%. In vitro gastrointestinal digestion revealed a markedly high bioaccessibility of
iAs (81.0–99.3% in the intestinal phase), far exceeding that of tAs (50.4–74.6%). Health risk
3.39% and 9.07%, respectively (3). This output accounted for 9.76% of the total freshwater
mately 3%. Apart from changes in concentration, elemental speciation can also undergo
while interacting with other food components (10). Likewise, arsenic species are not stable
intestinal phase (47.2–113%) than in the gastric phase (20.1–82.2%) for rice grains by using
arsenic bioaccessibility in the intestinal phase compared to Indica rice (71.1% vs. 83.1%).
J&K Scientific Ltd. (Beijing, China). Stock standard solutions of total arsenic (1000 mg/L)
90.45% of the national crayfish output (3). We selected 12 sampling areas across the five
with the certified value of 6.80 ± 0.64 mg/kg, with the relative standard deviation (RSD)
A decreasing from 100% to 0%; 15–20 min, A increasing from 0% to 100%; followed by a
the range of 1.1~2.0 µg/kg, based on a signal-to-noise ratio of 3:1. Matrix spike recovery
experiments were conducted by spiking raw abdominal muscle samples with 20 µg/kg
of each arsenic species, with the recoveries ranging from 90.5% to 107.4%. The RSD of
repeated measurements (n = 3) was less than 10%. Detailed methodological information is
are summarized in Table S3, with the electrolyte stock solutions prepared as specified in
Bioaccessibility (%) = (Cd × Vd )/(Cs × Ms) × 100
mined. As shown in Table 1, the tAs in the 60 samples varied widely, ranging from 53.6 to
419.9 µg/kg, with a mean value of 109.3 µg/kg and a median of 91.1 µg/kg. This distribu-
the edible portion of crayfish (109.3 µg/kg) was higher than that reported for many other
Table 1. Concentration and proportion of arsenic species in crayfish abdominal muscle (wet weight).
Arsenic Minimum Maximum Mean Median 90th Percentile Mean
abundant species, with their combined mean concentrations accounting for 78.0% of the
levels, with a mean concentration of 12.5 µg/kg, representing only 11.6% of the mean tAs.
Furthermore, the 90th percentile value for iAs was 16.4 µg/kg, indicating that even in
rather low. The maximum detected iAs concentration (80.7 µg/kg) was greatly below both
the European Union maximum level for iAs in crustaceans (0.1 mg/kg) and the Chinese
national standard limit for iAs in aquatic products (0.5 mg/kg) (24,25).
AsB (mean proportion of 41.3%) and a relatively low proportion of iAs (11.6%), aligns
measured tAs concentration. The results showed that ΣAs species accounted for 92.7%
arsenic speciation analysis, the incomplete recovery (approximately 7.3% unaccounted for)
tAs and iAs, by 32.2% and 28.2%, respectively. This finding aligns with the phenomenon
groups (31). These covalent bonds remain stable under boiling and high-salt conditions,
represent the standard deviation (n = 5). Different letters within the tAs and iAs groups indicate
tAs exhibited a progressive pattern, with low bioaccessibility in the oral phase (11.3–25.1%),
rising in the gastric phase (30.6–51.9%), and reaching the highest levels in the intestinal
phase (50.4–74.6%). This stepwise release aligns with the sequential digestion of protein-
Only minor release was observed in the oral phase (0–11.2%), followed by a rapid increase in

Methods (brief)

60 samples revealed total arsenic (tAs) concentrations ranging from 53.6 to 419.9 µg/kg,
by 28.2%. In vitro gastrointestinal digestion revealed a markedly high bioaccessibility of
consumers of high-iAs samples exceeded the acceptable threshold of concern. These find-
Copyright: © 2026 by the authors. choline (AsC), monomethylarsonate (MMA), and dimethylarsinate (DMA) are significantly
low-toxicity organic arsenic species dominate, with DMA and AsB showing a strong
intake to its potential health risk. In recent years, various in vitro digestion methods have
(As(III), As(V), MMA, DMA, AsC, AsB) in the abdominal muscle of crayfish from the major
digestion model is used to evaluate the bioaccessibility of tAs and iAs. Finally, a dietary
and six arsenic species (As(III), As(V), MMA, DMA, AsC, and AsB) were acquired from the
2.2. Sample Collection and Preparation
markets were randomly selected for sample collection. A total of 60 crayfish samples were
collected from June to August 2022. The sampling locations, as illustrated in the map
( ). All collected crayfish were adults. They were transported to the laboratory on the
previous study (19). Briefly, 0.500 g of homogenized muscle sample was weighed into a
Teflon digestion vessel in triplicate and subjected to pre-digestion with 5 mL of concentrated
vessel was then placed in a microwave digestion system and subjected to a heating program
designed to achieve complete digestion. After cooling to room temperature, the resulting
Agilent 7700x ICP-MS (Agilent Technologies, Tokyo, Japan).

Implications

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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