Winiarska-Mieczan et al. 2023 — Cd and Pb in Polish culinary herbs and spices
This Polish study measured cadmium and lead in 432 samples of culinary herbs and spices purchased in Lublin, eastern Poland: 100 dried herb samples across 9 species, 184 fresh herb samples across 15 species, and 148 single-component spice samples across 14 species. Analysis was by graphite furnace AAS (GF-AAS). Mean Cd was highest in dried herbs (0.134 mg/kg fresh weight), far above fresh herbs (0.004 mg/kg) and spices (0.017 mg/kg). Mean Pb was also highest in dried herbs (0.548 mg/kg), compared to fresh herbs (0.039 mg/kg) and spices (0.064 mg/kg). All calculated exposure metrics (% TWI, % BMDL, CDI, THQ, HI) were well below 1 at typical Polish consumption of 0.7 g/day of herbs and 0.7 g/day of spices. However, Cd exceeded the EU maximum level in dried coriander (mean 0.419 mg/kg) and estragon (mean 0.427 mg/kg), and Pb exceeded the limit in several fresh herbs: watercress, jiaogulan, celery, basil, and dill.
Key numbers
Concentrations expressed in mg/kg fresh weight:
Dried herbs (n=100):
- Cd: mean 0.134 ± 0.168, max 0.493, median 0.047, p25 0.047; LOQ 0.0002 mg/kg
- Pb: mean 0.548 ± 0.161, max 0.913, median 0.555, p25 0.555
- Cd exceeded 0.3 mg/kg EU limit in: dried coriander (mean 0.419 mg/kg) and estragon (mean 0.427 mg/kg); 20% of coriander and 30% of estragon samples exceeded
Fresh herbs (n=184):
- Cd: mean 0.004 ± 0.007, max 0.028, 19% below LOQ
- Pb: mean 0.039 ± 0.033, max 0.122, 8% below LOQ
- Pb exceeded 0.3 mg/kg fresh herb limit in: watercress, jiaogulan, celery, basil, dill
Single-component spices (n=148):
- Cd: mean 0.017 ± 0.019, max 0.057, 32% below LOQ; no sample exceeded 0.3 mg/kg limit
- Pb: mean 0.064 ± 0.050, max 0.160, median 0.044; no sample exceeded limit
- Highest Cd spices: cumin > lemon pepper > black pepper > cinnamon > ginger
- Highest Pb spices: allspice > cayenne pepper > pink peppercorn > ginger > black pepper
Dried vs. fresh comparison (per dry weight basis): Cd and Pb were both significantly higher (P<0.05) in dried than fresh herbs, attributed to perennial vs. annual plant age, phosphate fertilizer use in commercial growing, and concentration during drying.
Regulatory limits applied:
- Fresh herbs: EU max 0.05 mg/kg Cd (Commission Reg. EC 1881/2006, amended), 0.3 mg/kg Pb (Polish regulation)
- Dried herbs/spices (>50% herbs): 0.3 mg/kg Cd, 2.0 mg/kg Pb (Polish regulation)
Exposure/risk:
- At 0.7 g/day dried herbs: EWI Cd = 6.57×10⁻⁴ µg/kg bw, corresponding to 3.75×10⁻⁴ % of TWI (2.5 µg/kg bw/week); EWI Pb = 2.69×10⁻³ µg/kg bw, corresponding to 3.65×10⁻⁴ % of BMDL01
- THQ for all products < 1; HI (Cd+Pb) < 1 for all categories
Methods (brief)
GF-AAS (graphite furnace atomic absorption spectroscopy, Varian Spectr AA 880). Sample digestion: dry ashing at 450°C for 12 hours with H₂O₂ as oxidant, then dissolved in 1M HNO3. LOD 0.001 mg/kg Cd, 0.011 mg/kg Pb; LOQ 0.0002 mg/kg Cd, 0.003 mg/kg Pb. Reference materials: INCT-TL-1 (tea leaves) recovery 103% Cd, 99% Pb; INCT-MPH-2 (mixed Polish herbs) recovery 94% Cd, 102% Pb. Reproducibility ≤5%. Statistical analysis: ANOVA with Duncan’s test, P<0.05. Fresh herbs were dried at 65°C for 24 h before analysis; reported both as fresh-weight and dry-weight equivalents.
Implications
Certification: Dried coriander and dried estragon exceeded the EU Cd limit in Polish retail. These are commonly used culinary herbs; HMT&C standards for dried herbs should specify Cd as an analyte of concern, not just Pb, and the threshold decision must account for the dried vs. fresh concentration differential. A batch sourced from commercial growing in phosphate-fertilizer-intensive regions may have elevated Cd even if fresh-herb Cd appears low. Supplier specification for country of origin and soil Cd status is the primary lever.
Courses: Clean illustration of the dried vs. fresh concentration effect: the same herb species shows ~30-fold higher Cd per fresh weight when dried, because moisture is removed but metal content is retained. This is critical for label-comparison literacy — a consumer seeing a mg/kg limit on dried herbs cannot directly compare it to a fresh-herb limit without a water-content conversion.
App: Dried herbs are a distinct ingredient class from fresh herbs in the risk model. The app should not apply fresh-herb contamination profiles to dried herb ingredients. The ingredient matrix field must distinguish these (dried-herbs vs. fresh-herbs), and contamination profiles should be maintained separately.