The authors characterised one commercial SPF 50 milk spray containing nano titanium dioxide and then measured how its metals and nutrients leach into seawater in the dark and under UV light. The sunscreen contained lead at 743 µg/kg and cadmium at 16.7 µg/kg alongside percent-level titanium and aluminium. Lead, cadmium, nickel, copper, manganese, molybdenum and cobalt were not listed in the product formulation.
Key numbers
Table 1 (author accepted manuscript, PDF p. 10), sunscreen content in µg/kg as sold, single printed values:
| Element | Sunscreen (µg/kg) | Background seawater, dissolved (nmol/L) |
|---|---|---|
| Al | 1.67 x 10^6 | 235 |
| Cd | 16.7 | 0.0552 |
| Co | 6.10 | 0.0693 |
| Cu | 170 | 1.14 |
| Mn | 254 | 5.27 |
| Mo | 137 | 92.6 |
| Ni | 47.5 | 2.43 |
| Pb | 743 | 0.0703 |
| Ti | 1.48 x 10^7 | 33.5 |
The text cites earlier sunscreen surveys (not in this collection) with lead from 27.0 to 1.75 x 10^3 µg/kg. The kinetic model estimates that bathers’ sunscreen raises dissolved metal concentrations off a typical Mediterranean beach by 7.53 x 10^-4 % (nickel) to 19.8 % (titanium) in the abstract, with the discussion giving 20 % for titanium, 4 % for aluminium and 0.2 % for lead. Release rates were higher under UV light for all elements except lead.
Methods (brief)
Metals (Al, Cd, Cu, Mn, Mo, Ni, Pb, Co, Ti) and total P and Si in the sunscreen were measured in triplicate by ICP-MS (PerkinElmer ELAN DRC-e) after chemical digestion. For release experiments, 0.8 g of sunscreen was added to 400 mL of filtered seawater in quartz vessels at 24 °C, under UV light (37.25 ± 3.59 W/m2) or dark, sampled from 0 to 24 h, and filtered at 0.22 µm. Seawater Cd, Co, Cu, Mo, Ni and Pb were preconcentrated with APDC/DDDC and checked against CASS-4 (recoveries 92 to 103 %). Corresponding author: araceli.rodriguez@unican.es.
Evidence fitness
The sunscreen row is a single commercial product, useful as one peer-reviewed data point that lead and cadmium occur at measurable levels in a nano titanium dioxide sunscreen. It is an adult product and a spray, so it bears on baby mineral sunscreens only as context. The seawater work is environmental, not an exposure measure.
Limitations
One product. Table 1 gives no SD although triplicate analysis is stated. Some model inputs look inconsistent (a modelled seawater volume of 2.58 x 10^-4 m3, and a predicted final titanium of 45 nmol/L that implies more than the stated 20 % rise over the 33.5 nmol/L background); the supplementary tables that would settle this are not in the collection. Arsenic and mercury were not measured.
Related evidence
- Sun/suntan products, mineral UV filters (dirty sibling of r10 chemical)
- Lead
- Titanium
- Sunscreen Products as Emerging Pollutants to Coastal Waters
Update history
No substantive edit history is available in this build. The full commit record is available in git.