This PLoS ONE paper estimates what beachgoers’ sunscreen adds to Mediterranean coastal waters. Its supplement lists metals in seven commercial sunscreens. Titanium was found in three products (6,302 to 14,855 µg/g), zinc in one (72,688 µg/g), aluminium in two and iron in one. Lead, cadmium, chromium, nickel and ten other elements were reported as not detected, but no detection limit is given.
Key numbers
Table S2, µg/g as sold, mean ± SD of three analytical replicates (PDF p. 9):
| Sunscreen | Al | Fe | Ti | Zn |
|---|---|---|---|---|
| 1 | nd | nd | 11146 ± 401 | nd |
| 2 | 342 ± 27 | 68.7 ± 3.7 | nd | nd |
| 3 | nd | nd | nd | nd |
| 4 | nd | nd | 6302 ± 973 | nd |
| 5 | nd | nd | nd | nd |
| 6 | 1071 ± 93 | nd | 14855 ± 1774 | nd |
| 7 | nd | nd | nd | 72688 ± 101 |
The caption states that Ag, Cd, Co, Cr, Cu, Mn, Mo, Ni, Si, Sr, Pb, Tl, V and Zr were not detected. In the environment, the highest values were in the unfiltered surface microlayer of the sampled beaches: titanium 38 ± 7 µg/L and zinc 10.8 µg/L (PDF p. 3, read from the page image). At a pristine beach, titanium was detected only in the total fraction of the surface microlayer, at 23.7 ± 1.7 ng/L.
Methods (brief)
Metals in sunscreen were measured by ICP-AES (PerkinElmer Optima 5300 DV) after chemical digestion. Three laboratory-made sunscreens of known Ti and Zn content served as reference materials (recoveries 108 ± 6 % for Ti and 101 ± 1 % for Zn). Seawater Zn was preconcentrated with APDC/DDDC and measured by ICP-MS against CASS-4. Corresponding author: atovar@imedea.uib-csic.es.
Evidence fitness
The table shows the order of magnitude of titanium and zinc in commercial sunscreens (about 0.6 to 1.5 % titanium and 7.3 % zinc by mass in the products where they were found). The absence of lead and cadmium is a method statement without a detection limit and cannot be used as an upper bound or as evidence that these products were free of those metals. The products are not identified as baby products.
Limitations
Seven products, identity and SPF not reported in the table despite the caption. ICP-AES is less sensitive than ICP-MS for trace lead and cadmium. Arsenic and mercury were not measured. The collection manifest describes eight products; the table has seven.
Related evidence
- Sun/suntan products, mineral UV filters (dirty sibling of r10 chemical)
- Titanium
- Zinc
- Sunscreens as a New Source of Metals and Nutrients to Coastal Waters
Update history
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