Heavy Metals Induced Health Risk Assessment Through Consumption of Selected Commercially Available Spices in Noakhali District of Bangladesh

Overview

This medRxiv preprint reports lead (Pb), cadmium (Cd), chromium (Cr), Cu, and Fe concentrations in 19 spice samples (15 non-branded, 4 branded) purchased from Sonapur and Maijdee marketplaces in the coastal Noakhali District of Bangladesh, paired with household-level ingestion-rate data from a 180-household survey across six clusters. Concentrations were measured by flame atomic absorption spectrometry (PerkinElmer PinAAcle 900H) after wet acid digestion. The authors compute Estimated Daily Intake (EDI), Total Hazard Quotient (THQ), Total Target Hazard Quotient (TTHQ), and cancer risk (CR) per sample using USEPA and WHO reference doses. The two HMI-relevant findings are: (a) chromium loading is the dominant non-carcinogenic risk driver across most powdered spices, with TTHQ exceeding 1 in ~37% of samples (coriander leaf, green chili, ginger, and all four chili-powder and turmeric-powder samples — branded and non-branded — drive this); (b) carcinogenic risk for Cr and Cd is above the 1×10⁻⁴ USEPA benchmark in coriander leaf, both turmeric-powder samples, both chili-powder samples, green chili, masala mix, and ginger. Cr is reported as total Cr (no hexavalent chromium (Cr-VI) speciation); arsenic (As), mercury (Hg), nickel (Ni), aluminum (Al), tin (Sn) are not measured. The source is a preprint and has not undergone peer review at the cited version.

Key numbers

Metals measured: Pb, Cd, Cr (total Cr, not speciated), Cu, Fe. Concentrations in mg/kg (= ppm), as reported by the authors (basis: dry/as-sold ground spice; method: PerkinElmer PinAAcle 900H AAS in triplicate after wet digestion in 1:4 HNO₃:H₂SO₄ at 130°C; R²=0.9897–0.9983; LOD = 0.01 ppm/mL).

Sample-level concentrations cannot be tabulated exhaustively from the source as supplied — Figure 2(a–e) provides per-sample bars and abstract-level summary statistics are the principal reported numeric synthesis. Reported abstract-level highs and category narrative below.

Highest concentration per metal (abstract; mean ± SD, mg/kg):

Metal	Highest in	Reported value (mg/kg)
lead (Pb)	Cardamom (S-7, non-branded)	15.47 ± 1.93
cadmium (Cd)	Coriander leaf (S-17, non-branded)	1.65 ± 0.01
chromium (Cr) (total)	Bay leaf (S-18, non-branded)	31.99 ± 3.97
Cu	Dried chili (S-6, non-branded)	18.84 ± 1.97
Fe	Black pepper (S-19, non-branded)	9.29 ± 1.72

Other narrative concentrations stated in Results:

Pb: cardamom 15.47 ± 1.93 highest, cinnamon (S-12) 10.05 ± 1.22 second.
Cd: coriander leaf 1.65 ± 0.01 highest, non-branded turmeric powder (S-2) 1.49 ± 0.02, branded turmeric powder (S-4) 1.43 ± 0.01.
Cr (total): bay leaf 31.99 ± 3.97 highest, coriander leaf 27.58 ± 1.50, cardamom 25.19 ± 2.26.
Cu: dried chili 18.84 ± 1.97 highest, non-branded chili powder (S-1) 15.36 ± 2.28, branded cumin (S-16) 13.81 ± 2.38.
Fe: text reports black pepper as highest at 9.29 ± 1.72; same Results paragraph then names green chili (S-5) 35.46 ± 3.94 and branded chili powder (S-3) 34.02 ± 3.18 — both larger than the “highest” figure. Figure 2(e) shows black pepper as the lowest, not the highest, Fe bar. See Verification notes.

Estimated Daily Intake (EDI) and risk metrics (Table 2, Table 3):

EDI order across spices: Fe > Cr > Cu > Pb > Cd.
Reference doses used (mg/kg-day): Pb 0.0035, Cd 0.0005, Cr 0.0003, Cu 0.04, Fe 0.007.
TTHQ > 1 (potential non-carcinogenic health risk): S-1 non-branded chili powder (4.59), S-2 non-branded turmeric powder (3.51), S-3 branded chili powder (2.72), S-4 branded turmeric powder (1.70), S-5 green chili (5.55), S-11 ginger (2.21), S-17 coriander leaf (8.33). Cr THQ is the dominant driver in each.
Cancer risk (CR > 1×10⁻⁴) for Cr and/or Cd in the eight samples explicitly enumerated by the authors (Results, page 14, just before Figure 3): “both branded and unbranded turmeric and chili powder, green chili, masala mix, ginger, and coriander leaf” → S-1, S-2, S-3, S-4, S-5, S-8 (masala mix), S-11 (ginger), S-17 (coriander leaf). Figure 3 visual inspection is consistent with this list and does not add other samples to the >1E-04 set.

Permissible limits cited by the authors (Mg/Kg/Day):

Pb 0.1 (USEPA), Cd 0.1 (USEPA), Cr 0.1 / 0.25 (USEPA / WHO), Cu 50 (Muhseen et al.), Fe 300 (WHO).
The authors state “none of the heavy metals exceeded the maximum permissible limits (MPL)” while simultaneously reporting TTHQ and CR exceedances; the MPL statement refers to per-day intake against the listed MPL columns, not per-kg concentration against food-safety limits.

Methods (brief)

Cross-sectional design. Nineteen commercially-available spice samples (50–125 g commercial sizes) were collected from Sonapur and Maijdee marketplaces in Noakhali (n=15 non-branded, n=4 branded). Spice-consumption frequency was collected from 180 households across six clusters via structured questionnaire; ingestion rate (IR) for the EDI calculation was derived from household daily/weekly usage. Wet digestion used 1:4 HNO₃:H₂SO₄ heated to 130°C for 1 h with 2 mL H₂O₂ added until digest cleared, then diluted to 50 mL with deionized water. Analysis: PerkinElmer PinAAcle 900H AAS, dual-beam optics with continuum-source double-beam background correction, deuterium arc lamp; triplicate measurement; linearity R²=0.9897–0.9983; LOD = 0.01 ppm/mL.

Health-risk calculations: EDI = (C_metal × IR) / BW; THQ = EDI / RfD; TTHQ = ΣTHQ; cancer risk = EDI × CSF. RfDs from USEPA (Pb, Cd, Cr, Fe) and Muhseen et al. (Cu); WHO MPL for Cu and Fe. The cancer risk computation reports CR for Cr and Cd (and a flat near-zero CR line for Pb — labeled “CR of Pd” in Figure 3, which the wiki reads as a typo for Pb).

Method limitations: Cr is reported as total Cr; the cancer-risk calculation assumes the Cr-VI cancer slope factor without speciation evidence, so the CR for Cr is an upper-bound assuming the worst-case speciation. No certified reference material is mentioned. No Hg, As, Ni, Al, or Sn measurement. Sample size per spice category is n=1 with triplicate analytical replicates — the standard deviations reflect instrumental replication, not biological/lot variation. The IR-from-household-survey approach overweights local consumption patterns and is not transferable outside Noakhali.

Implications

Certification: Treat this preprint as B-tier occurrence context for South Asian informal-market spice supply. The Cd and Cr levels in chili powder, turmeric powder, ginger, coriander leaf, bay leaf, and cardamom are consistent with the broader literature documenting Cd and Pb hot-spots in unmonitored Bangladeshi/South-Asian spice supply. Do not pull single-sample maxima into HMI threshold math: n=1 per spice category and the absence of certified reference material put this study outside A-tier occurrence anchors. The cancer-risk values for Cr that assume Cr-VI without speciation are an upper bound and should be flagged as such if cited downstream.

Courses: Useful for the contamination-pathway module — coastal-area soil contamination, informal-market lack of routine regulatory sampling, and turmeric/chili adulteration history are explicitly cited by the authors. Pair with the Cowell et al. 2017 ground-turmeric-Pb-in-US-recalls reference (cited in this paper as ref 13) and the Rahman 2020 / Akter 2016 prior Bangladesh turmeric-Pb studies for a regional thread.

App: Contributes a Bangladesh-informal-market scenario for spices as a Cd-, total-Cr-, and Pb-relevant ingredient category. The contamination signal is strong for chili powder, turmeric powder, coriander leaf, ginger, and bay leaf; individual-sample maxima should not be used as typical-occurrence anchors.

Update history

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