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Exposure to Lead and Cadmium in the Sixth Total Diet Study — China, 2016–2019

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Overview

Zhao and colleagues report the lead and cadmium exposure component of the Sixth China Total Diet Study, covering 288 composite food samples across 24 provincial-level administrative divisions (PLADs) and ~86% of the Chinese population. Pb and Cd were quantified by ICP-MS in 12 food categories. The national mean dietary intake for adult males was 0.318 µg/kg bw/day for Pb (MOE > 1 in all 24 PLADs) and 8.26 µg/kg bw/month for Cd (33.0% of PTMI nationally); Hunan Province adult males exceeded the PTMI for Cd at 120%, primarily driven by cereals (rice).

Key numbers

  • Six TDS round (2016–2019); 24 PLADs; 12 food categories per PLAD → 288 composite samples total (Foreword + article p. 176).
  • Pb LOD 0.08 µg/kg; Cd LOD 0.05 µg/kg by ICP-MS; samples below LOD set to 1/2 LOD per WHO method (p. 176).
  • Detection rate: 99.3% for Pb; 88.9% for Cd across 288 PLAD composites (p. 176).
  • National mean (µg/kg) by food category — Pb (mean ± SD, min–max): Cereals 11.9±20.6, 1.2–47.6 (DR 100%); Legumes 12.9±15.5, 4.7–34.9 (100%); Potatoes 11.2±16.2, 0.4–35.5 (100%); Meats 10.3±15.3, 1.3–28.9 (100%); Eggs 9.7±12.4, <LOD–25.3 (95.8%); Aquatic foods 14.1±19.4, 2.2–37.4 (100%); Dairy products 1.6±2.6, <LOD–4.8 (95.8%); Vegetables 15.7±24.4, 3.6–54.0 (100%); Fruits 5.0±8.6, 0.3–19.1 (100%); Sugar 9.7±30.4, 0.4–75.0 (100%); Beverages & water 1.9±2.7, 0.2–5.7 (100%); Alcohol 1.9±3.4, 0.1–7.1 (100%) (Table 1, p. 177).
  • National mean (µg/kg) by food category — Cd (mean ± SD, min–max): Cereals 14.5±33.5, 3.0–83.2 (DR 100%); Legumes 16.8±18.5, 4.5–41.9 (100%); Potatoes 11.1±14.4, 2.3–30.8 (100%); Meats 2.4±3.7, 0.6–8.1 (100%); Eggs 1.1±4.0, 0.1–9.0 (100%); Aquatic foods 16.9±46.3, 0.9–83.8 (100%); Dairy products 0.1±0.5, <LOD–0.9 (50.0%); Vegetables 12.5±19.1, 2.9–46.6 (100%); Fruits 0.9±1.7, 0.3–4.3 (100%); Sugar 3.4±19.5, 0.1–49.0 (100%); Beverages & water 0.1±0.4, <LOD–0.4 (50.0%); Alcohol 0.35±1.3, <LOD–2.9 (66.7%) (Table 1, p. 177).
  • Highest mean Pb foods (µg/kg): vegetables 15.7; aquatic foods 14.1; legumes 12.9; cereals 11.9; potatoes 11.2.
  • Highest mean Cd foods (µg/kg): aquatic foods 16.9; legumes 16.8; cereals 14.5; vegetables 12.5; potatoes 11.1.
  • Mean dietary Pb intake for Chinese adult male 0.318 µg/kg bw/day (range 0.103–0.746 across 24 PLADs); north 0.326, south 0.310 µg/kg bw/day.
  • MOE for Pb computed against BMDL₀.₁ = 1.2 µg/kg bw/day; MOE > 1 in all 24 PLADs (range 1.6–11.7) — within acceptable level for all adult-male populations.
  • Top 3 dietary Pb sources nationally: cereals 43.5%; vegetables 29.0%; beverages and water 9.8%. Northern PLADs: cereals 50.6%, vegetables 19.7%. Southern PLADs: cereals 31%, vegetables 37.1%.
  • Mean dietary Cd intake for Chinese adult male 8.26 µg/kg bw/month (range 2.60–30.02 across 24 PLADs); southern regions 11.96, northern regions 4.55 µg/kg bw/month.
  • Cd dietary intake as % PTMI (25 µg/kg bw/month) across 24 PLADs: 10.4% to 120%. Only Hunan adult males (120% PTMI) exceeded the PTMI; primarily driven by cereal contribution of up to 76% (rice).
  • Hunan cereal Cd mean 83.17 µg/kg = 5.8× national cereal Cd mean (14.45 µg/kg).
  • Main national Cd contributors: cereals 56.3%; vegetables 26.6%.
  • Reference daily Pb intakes from prior TDS rounds: TDS1 86 µg/person/day → TDS6 20 µg/person/day; ~47% decrease vs TDS5.
  • Reference daily Cd intakes from prior TDS rounds: TDS1 13 µg/person/day → TDS6 17 µg/person/day (slight increase trend across rounds 1–5, 47% decrease from TDS5 to TDS6).
  • Body weight reference: 63 kg standard Chinese man (Foreword Methodology, p. 159).

Methods (brief)

Pb and Cd were quantified in TDS composite food samples by ICP-MS (LOD 0.08 µg/kg Pb; 0.05 µg/kg Cd); values below LOD set to 1/2 LOD per WHO methodology. The Sixth TDS expanded coverage to 24 PLADs (vs. 12 in TDS1–4 and 20 in TDS5), covering ~86% of the Chinese population. Sampling was conducted 2016–2019 via household dietary surveys (n>40,000 individuals; 24-hour recall × 3 consecutive days) at multiple sites per PLAD. Foods cooked using local methods, then composited per food category at 12 PLAD-level samples × 24 PLADs = 288 composites. Point-estimate dietary intake calculated against the BMDL₀.₁ (1.2 µg/kg bw/day) for Pb using MOE approach (JECFA withdrew the PTWI for Pb at the 73rd meeting) and PTMI (25 µg/kg bw/month) for Cd. Adult-male standard body weight 63 kg. The paper does not perform Pb or Cd speciation; both are total elemental concentrations measured by ICP-MS.

Implications

  • Certification (HMTc): Adds 288 PLAD-level Chinese TDS composite-sample occurrence values for Pb and Cd across 12 food categories on as-consumed cooked basis. Direct evidence for Cereals, Rice (cereal-cohort), Vegetables, and Legumes Pb and Cd profiles in the Chinese diet context. The Hunan cereal Cd hotspot (83.17 µg/kg) is a notable single-region outlier informing regional sourcing risk discussions.
  • Courses: Useful as a TDS-methodology case study and as evidence of geographic variance (north vs south) for QA, regulatory affairs, and sourcing audiences.
  • App: Contributes occurrence data points across 12 food categories on as-consumed basis; complements raw-ingredient data with cooked/composite values; informative for risk-by-region modeling against Chinese dietary patterns.

Update history

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