Heavy metal content in mixed and unmixed seasonings on the Ghanaian market

Overview

Darko and colleagues measured Fe, Zn, Cu, cadmium (Cd), lead (Pb), and mercury (Hg) in 22 mixed and unmixed powdered seasonings purchased from markets in Kumasi, Ghana. Flame atomic absorption spectrometry was used for Fe, Zn, Cu, Cd, and Pb, while mercury was measured by cold-vapour atomic absorption spectrometry. The occurrence finding for HMI target analytes is that Pb was detected across the seasoning set, Cd was detected in a smaller subset, and Hg was below the detection limit in every seasoning. The authors report grouped ranges for mixed and unmixed seasonings and interpret Pb and Cd as the main toxic-metal concern in this sample set.

Key numbers

The highest reported Cd value in unmixed seasonings was 0.9 mg/kg in nutmeg, while the rest of the unmixed seasonings were below the detection limit. In mixed seasonings, the highest Cd value was 0.06 mg/kg. For Pb, unmixed seasonings ranged from 0.6 to 1.8 mg/kg and mixed seasonings from 0.63 to 1.39 mg/kg. The source discusses individual seasoning types and source countries, but this page keeps the evidence at the grouped product-form level.

Methods (brief)

Twenty-two powdered seasonings were purchased from local shops and hawkers in Kumasi after preliminary investigation identified them as commonly consumed seasonings in the metropolis. Samples were grouped as unmixed or mixed seasonings, dried at 45°C for 24 h, cooled, stored in plastic bags, then digested using the Akagi and Nishimura method: about 1 g sample, water, HCl, HNO3:HClO4, and H2SO4, heated at 200°C until clear, filtered, and diluted to 50 mL. Fe, Zn, Cu, Cd, and Pb were determined by air-acetylene flame atomic absorption spectrometry using a Spectr AA 220 instrument; Hg was determined with an HG-5000 automatic mercury analyzer by cold-vapour atomic absorption spectrometry. The source reports Cd and Hg detection-limit language as 0.01 mg/kg and does not speciate mercury.

Implications

This source adds Ghana-market occurrence data for powdered spices, herbs, and seasoning blends, with direct relevance to the spices and condiments-general product routes. Its strongest HMI-target finding is that every one of the 22 sampled seasonings reported a Pb value above the FAO/WHO (2003) 0.3 mg/kg permissible limit for spices, with unmixed-seasoning Pb ranging 0.6-1.8 mg/kg and mixed-seasoning Pb ranging 0.63-1.39 mg/kg. Cd was detected in 23% of samples, with nutmeg (0.9 mg/kg) the single point above the FAO/WHO (2001) 0.20 mg/kg spice comparator. Hg should be routed as total mercury context only and specifically as non-detect at the reported 0.01 mg/kg detection limit. Fe, Zn, and Cu were measured on the same analytical panel and are retained in the page body for source context only; they are not HMI target analytes.

Update history

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