Release of compounds from sunscreens into seawater studied

Women with yellow sun glasses in front of a pink background


Women with yellow sun glasses in front of a pink background

Titanium dioxide from sunscreen is polluting beaches (picuture: adobe:240_F_64530270_Wob3vRjW2Km9NOyflFhcEiLlBl7EBXwX)

Researchers have studied how sunscreens release different compounds such as trace metals and inorganic nutrients into Mediterranean seawater. They conclude, that more research is needed to determine how these metals and nutrients, which are normally present at very low amounts in seawater, could be affecting marine ecosystems.
However, sunscreens are indispensable to avoid human skin cancer as different other important studies have proven and recently reiterate by the Skin Care Foundation.

Millions of people are hitting the beach slathered in sunscreen this summer. Some might choose “coral-safe” sunscreens that lack oxybenzone and octinoxate, the two substances most widely linked to coral reef damage. Scientists don’t yet know what effects other trace compounds in sunscreens might have on marine ecosystems. As a first step, researcher Araceli Rodríguez-Romero and colleagues from the University of Cantabria, Spain wanted to determine how quickly sunscreen releases trace metals and nutrients into seawater, and how sunscreen from beachgoers’ bodies could impact the overall levels of the compounds in coastal waters.

Release of compounds from sunscreen

The researchers added a commercial, titanium-dioxide-containing sunscreen to samples of Mediterranean seawater and observed how droplets of the lotions released various metals and nutrients into the water. Some compounds entered the seawater more quickly after UV treatment, which simulated sun exposure. Aluminum, silica and phosphorous had the highest release rates under both light and dark conditions. The team used these data to develop a model that predicts the release of compounds from sunscreen under different conditions. Then, they used the model to estimate that, on a typical summer day at the beach, beachgoers could increase the concentration of aluminum in coastal waters by 4% and of titanium by almost 20%.

Challenge for Formulators

Different studies have clearly shown that sunscreens are indispensable means of preventing skin cancer. Recently the American Skin Cancer Foundation stated in a comment: “There is, however, substantial evidence showing that sunscreen helps reduce skin cancer risk, as well as skin aging.  Daily use of an SPF 15 or higher sunscreen reduces the risk of developing squamous cell carcinoma (SCC) by about 40 percent and melanoma by 50 percent.” Thus the sunscreen formulators face a challgenge: developming  sunscreens that provide maximum protection for human skin with minimal impact on the marine ecosystem.

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