Liang et al. 2019 - Heavy metals in Beijing foodstuffs: concentrations and health risk

Liang et al. measured Cd, Cr, Pb, total As, and total Hg in 25 foodstuff types collected in Beijing, China, then estimated dietary intakes, weekly intakes, and non-carcinogenic target hazard quotients (THQs) for local adults. The sampled foods covered cereals, vegetables, fruits, meat, and fish/shellfish. The paper is useful for broad dietary-exposure context, but it does not speciate arsenic or mercury and it contains one source-side mismatch between the narrative exceedance list and the values in Table 1.

Key numbers

Study design:

• Sample coverage: 25 foodstuff types from four Beijing collection sites, with three replicates per foodstuff type at each site (25 x 4 x 3 = 300 sample replicates; Methods section).
• Food groups: fish/shellfish (crucian carp, carp, white amur, hairtail, shrimp), vegetables (carrot, haricot bean, eggplant, cauliflower, cucumber, onion, cabbage, potato, white gourd), cereals, meat (pork, beef, mutton, chicken), and fruits (apple, pear, banana) (Methods and Table 1). The Methods text names cereal items as millet, flour, corn, and rice, while Table 1 reports millet, corn flour, and wheat flour and does not show a separate rice row; see Verification notes.
• Measurement basis: concentrations are reported as mg/kg dry weight in the paper’s Figure 1 and Table 1.

Group mean concentrations by food group (mg/kg dry weight; Figure 1 text):

Selected individual Table 1 values (mg/kg dry weight, mean +/- SD):

• Millet: Cr 0.057 +/- 0.006; Cd 0.027 +/- 0.005; Pb 0.072 +/- 0.018; tAs 0.026 +/- 0.007; tHg 0.023 +/- 0.006.
• Corn flour: Cr 0.076 +/- 0.050; Cd 0.003 +/- 0.002; Pb 0.060 +/- 0.028; tAs 0.007 +/- 0.002; tHg 0.018 +/- 0.013.
• Wheat flour: Cr 0.234 +/- 0.038; Cd 0.023 +/- 0.007; Pb 0.045 +/- 0.017; tAs 0.024 +/- 0.007; tHg 0.020 +/- 0.014.
• Chicken Pb: 0.291 +/- 0.117; white gourd Pb: 0.227 +/- 0.100; fish/shellfish Pb values above 0.2 mg/kg include crucian carp 0.227 +/- 0.122, white amur 0.322 +/- 0.174, hairtail 0.276 +/- 0.168, and shrimp 0.240 +/- 0.097.
• The Results text says Pb in “pork” exceeded 0.2 mg/kg, but Table 1 reports pork Pb as 0.029 +/- 0.049 mg/kg and beef Pb as 0.201 +/- 0.111 mg/kg. See Verification notes.

Estimated dietary intake by food group (ug/day; Table 2):

Dietary contribution patterns reported by the authors (Figure 2 text):

• Vegetables and cereals accounted for 91.5% of total Cd intake, 67.1% of total Pb intake, and 53.8% of total tAs intake.
• Cereals were the largest contributor to tHg intake at 46.6%, followed by fish at 26.7%.
• Meat and vegetables were the two largest contributors to Cr intake, at 29.3% and 26.7%, respectively.

Weekly intakes compared with PTWIs (ug/kg bw/week; Table 3):

THQs and TTHQs by food group (Table 4):

Risk-contribution percentages from the THQ section:

• Cr contributed 41.7% of the total TTHQ across all metals and food groups.
• tAs and tHg contributed 8.3% and 3.9%, respectively.
• Vegetables contributed 38.2% of the total TTHQ according to the Results text; the abstract gives 38.8%. Table 4 supports approximately 38.3% (0.88 / 2.30).

Method detection limits (MLODs; Methods section):

• Cd: 0.01 mg/kg.
• Cr: 0.05 mg/kg.
• Pb: 0.12 mg/kg.
• tAs: 0.40 ug/kg.
• tHg: 0.25 ug/kg.

Methods (brief)

The authors collected common Beijing foodstuffs from local markets, washed the food samples with deionized water, oven-dried them, ground them to powder, and digested 0.2 g dry sample portions with HNO3/H2O2 at 160 deg C. Cd, Cr, and Pb were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES; SPECTRO Analytical Instruments GmbH). Total As and total Hg were measured by atomic fluorescence spectrometry (AFS-930; Beijing Jitian Instrument Co., Ltd.). The paper reports total As and total Hg only; it does not separate inorganic arsenic from organic arsenic, methylmercury from inorganic mercury, or hexavalent chromium from total chromium.

Health-risk calculations used estimated daily intake, weekly intake relative to FAO/WHO provisional tolerable weekly intakes, and US EPA-style target hazard quotients. The dietary-intake calculations use average Beijing food-consumption rates from the cited dietary survey rather than a product-category sampling frame.

Implications

Standards work: This source contributes Beijing-specific occurrence and dietary-exposure data for mixed foodstuffs, especially cereal grains, fish/shellfish, meat, vegetables, and fruit. It is not directly substitutable for HMT&C analytes that require speciation: tAs cannot be treated as iAs, and tHg cannot be treated as MeHg.

Courses: The paper is a useful teaching example for why high-consumption staples can dominate exposure even when their concentrations are lower than fish or meat. In this dataset, cereals and vegetables dominated Cd, Pb, and tAs intake contributions, while cereals dominated tHg intake because of consumption volume.

App: The source is best treated as regional dietary-exposure context for China rather than as a product-specific concentration benchmark. Any app use should preserve dry-weight basis, total-speciation labels, the small replicate design, and the source-side Pb exceedance caveat.

Wiki pages this source may touch

• lead
• cadmium
• chromium
• arsenic-total
• mercury-total
• rice
• wheat
• corn
• non-rice-grains
• vegetables
• fish
• shellfish
• meat
• fruit
• fresh-fish
• shellfish
• seafood
• beef-product
• pork-product
• poultry-product
• lamb-mutton
• fresh-fruit
• china-gb-2762-2012-contaminants-superseded

Verification notes

• Merge-enhanced 2026-05-18 from the full Manual Fetch Kimi PDF. The previous page used the generic manual-fetch-kimi raw handle, a truncated raw path, empty product routing, and invalid links to nonexistent wheat-flour, millet, and China GB 2762 pages.
• Fresh-context audit (Codex subagent, 2026-05-18) caught two source-fidelity errors in the merge-enhance: sample replicates were corrected from 75 to 300 (25 foodstuff types x four sites x three replicates per type per site), and digestion mass was corrected from 0.50 g to 0.2 g per Methods.
• Paper-internal food-list caveat: the Methods section names 25 foodstuff types and lists cereals as millet, flour, corn, and rice, while Table 1 visibly reports millet, corn flour, and wheat flour, omits a separate rice row, and prints onion twice. This page records both rather than forcing the Table 1 list to reconcile to 25 named types.
• Paper-internal caveat: the Results text says Pb in chicken, fish, white gourd, and pork exceeded China’s 0.2 mg/kg Pb limit. Table 1 supports chicken, multiple fish/shellfish entries, and white gourd; it reports pork Pb as 0.029 +/- 0.049 mg/kg and beef Pb as 0.201 +/- 0.111 mg/kg. This page preserves the mismatch rather than silently substituting beef for pork.
• Paper-internal rounding/text caveat: the abstract says vegetables contributed 38.8% of the total TTHQ, while the Results section says 38.2%; Table 4 supports approximately 38.3% from 0.88 / 2.30.
• Speciation discipline: arsenic and mercury are recorded as tAs and tHg because the paper measured total elements only.

Page history

The five most recent substantive edits to this page. 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.