Determination of some soft drink constituents and contamination by some heavy metals in Nigeria

Overview

Godwill and colleagues measured cadmium, lead, and total mercury in 26 Nigerian soft-drink and juice samples purchased from local grocery stores in Enugu, Enugu State. Heavy metals were quantified by atomic absorption spectrophotometry after nitric-acid digestion. The paper reports lead in all samples, mercury in most samples, and cadmium in one sample, with all concentration units preserved as mg/L.

Key numbers

• Sample frame: 26 soft-drink and juice samples purchased from local grocery stores in Enugu, Enugu State, Nigeria.
• Cadmium: Table 3 reports cadmium as detectable in 1 of 26 samples at 0.149 mg/L; the remaining 25 samples are reported as ND. Table 3 reports cadmium (Cd) mean 0.0057 mg/L and S.D. 0.029.
• Lead: Table 3 reports lead in all 26 samples, with values from 0.171 mg/L to 3.392 mg/L; the abstract/results prose summarizes this as 0.17 to 3.39 mg/L with a mean of 0.8, while Table 3 reports mean 0.81 mg/L and S.D. 0.74.
• Total mercury: Table 3 reports total mercury as ND in 4 of 26 samples and quantified in 22 samples. Table 3 quantified values span 0.069 mg/L to 11.325 mg/L, with mean 2.08 mg/L and S.D. 3.08. The abstract/results prose instead summarizes the range as 0.29 to 11.32 mg/L; the table values are preserved here and the mismatch is flagged in Verification notes.
• Table 3 comparison values are reported as MCLG/MCL 0.005/0.005 mg/L for cadmium, 0.00/0.015 mg/L for lead, and 0.002/0.002 mg/L for mercury.
• The paper also reports pH values from 2 to 5 in Table 2, with mean pH 3.62 and S.D. 0.75; acid levels ranged from 3.26 g/L to 13.06 g/L, with mean 10.91 g/L and S.D. 2.36.

Methods (brief)

The authors digested 25 ml of each beverage sample with 10 ml of 69% concentrated nitric acid, evaporated the mixture until brown fumes disappeared, diluted/concentrated the digest, made up the final volume to 50 ml, filtered it, and analyzed the solution by atomic absorption spectrophotometer using a Varian AA240 model. Calibration solutions were prepared from 1000 ppm stock standards, and absorbance was measured at 228.8, 283.3, and 253.7 nm for cadmium, lead, and mercury respectively. The paper reports total cadmium, total lead, and total mercury only; mercury is not speciated into methylmercury or inorganic mercury. It does not report LOD/LOQ values beyond using ND in Table 3.

Related evidence

• Cadmium
• Lead
• Mercury, Total
• Beverages
• Soft drink bases
• Fruit Juice
• Category 5: Beverages
• Soft Drinks/Carbonated Beverages
• Fruit Juices, Non-Apple

Update history

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