Overview
Li and colleagues sampled grapes across 11 Chinese provinces, plus an e-waste dismantling area and pesticide-free courtyards, separated skins from pulps and measured seven elements by ICP-MS on a dry-weight basis. Skins carried more of most metals than pulps, and washing removed some surface copper and lead.
Key numbers
- All samples (n = 41): lead mean 0.24 µg/g dw in skins and 0.37 µg/g dw in pulps (pulp mean from a single detect); cadmium 0.07 and 0.02 µg/g dw; arsenic 0.25 and 0.26 µg/g dw (Table 1, p. 3).
- Market grapes (n = 29): skin lead up to 5.11 µg/g dw (Table 1).
- Lead detected in 95.7% of skins but 2.44% of pulps; washing removed about 66.7% of skin lead (p = 0.06) (Discussion, pp. 5-6).
Methods (brief)
Lyophilized skins and pulps (0.2 g) microwave-digested with nitric acid and hydrogen peroxide; Agilent 7500 ICP-MS. Peach-leaf and tea-leaf reference materials; lead recovery 70.2 ± 5.1%, others 79 to 119%.
Evidence Fitness
Nationwide coverage with reference-material QA, but means use detected values only, detection limits are not printed and results are dry weight. Lead recovery was low (about 70%). A market skin manganese maximum of 2013 µg/g looks like a misprint. Grapes are measured directly and are a member of the non-apple fruit group.