Milani and colleagues optimized an ultrasound acid digestion method for ICP-OES determination of total arsenic, cadmium, and lead in 72 non-centrifugal cane sugar (NCS) samples, also known as rapadura or brown sugar, purchased from local markets in Brazil (n=16), Colombia (n=36), Ecuador (n=12), Mexico (n=3), and Peru (n=5). Lead was detected and quantified in every sample. Cadmium was detected in 31 percent of samples and quantified in 7 percent. Total arsenic was below the limit of quantification in all samples.
Key numbers
Lead, country means and ranges, µg/kg, dry weight as sold (Table 4):
- Brazil (n=16): mean 85, range 65 to 118
- Colombia (n=36): mean 74, range 67 to 92
- Ecuador (n=12): mean 96, range 78 to 108
- Mexico (n=3): mean 101, range 81 to 122
- Peru (n=5): mean 107, range 85 to 119
33 percent of all 72 samples exceeded the Brazilian and MERCOSUR sugar limit for lead of 100 µg/kg (Results text, Section 3.2). These samples came from Minas Gerais and Rio Grande do Sul (Brazil), Quito and Vilcabamba (Ecuador), Mexico, and La Victoria and Lima (Peru).
Cadmium, country means and ranges, µg/kg (Table 4):
- Brazil (n=16): mean below LOQ, range below LOQ to below LOQ
- Colombia (n=36): mean 1 µg/kg, range below LOQ to 43 µg/kg
- Ecuador (n=12): mean below LOQ, range below LOQ to below LOQ
- Mexico (n=3): mean 5 µg/kg, range below LOQ to 15 µg/kg
- Peru (n=5): mean 18 µg/kg, range below LOQ to 45 µg/kg
LOQ for cadmium was 15 µg/kg. The text states 31 percent of samples were detectable and 7 percent were quantifiable (Section 3.2). No Brazilian or MERCOSUR limit exists for cadmium in this food type.
Total arsenic: all 72 samples were below the LOQ of 37 µg/kg (Table 4). The Brazilian and MERCOSUR limit for arsenic in sugar is 100 µg/kg; all samples were within this requirement.
Methods (brief)
1.0 g samples were dissolved in 7.5 mL purified water with 1.5 mL nitric acid and 0.75 mL hydrogen peroxide, extracted in an ultrasound bath at 45 degrees C for 20 minutes (15 percent oxidant mixture), and analysed by ICP-OES (Agilent 5100 VDV). The method was validated against INMETRO and AOAC guidelines. LOD values: arsenic 12 µg/kg, cadmium 5 µg/kg, lead 12 µg/kg. LOQ values: arsenic 37 µg/kg, cadmium 15 µg/kg, lead 39 µg/kg. CRM recoveries (INCT-TL-1 tea leaves): arsenic 93 percent, cadmium 93 percent, lead 93 percent (Table 3). Values below the LOQ were treated as zero for exposure assessment.
Evidence fitness
This study provides direct NCS/rapadura occurrence data for lead and cadmium across five Latin American countries with ICP-OES analysis and CRM verification. Lead coverage is complete (all 72 samples above LOQ). Cadmium coverage is partial because 93 percent of Brazil and Ecuador samples were below the LOQ of 15 µg/kg. Total arsenic was not speciated; inorganic arsenic values cannot be derived from this paper. The matrix is NCS/rapadura, an artisanal unrefined product that is distinct from refined white cane sugar or beet sugar; contamination levels in NCS reflect retained mineral content from the whole-cane process and may not represent commercially refined sugar.
Limitations
Mexico and Peru sample sizes are small (n=3 and n=5). Collection dates are not reported. The paper measures total arsenic only and cannot be used to determine inorganic arsenic content. Cadmium detection was low except in Peru; the Colombia and Ecuador LOQ treatment as zero may understate true cadmium occurrence.
Related evidence
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