Sunblock blocks sea ecology

A day at the beach can be wonderful and cleansing to the body and soul, provided you are at peace with sand inevitably finding its abrasive way into your nether regions. As part of the enjoyment, of course, there is a recognised need to protect yourself against sun damage to your skin and so sun creams or sunblocks are “slapped” on to provide protection. The problem, according to a new study is that your sunblock might be causing some problems for the ecology of the coastal waters in which you are splashing.

The researchers for the new study were motivated by the observation that sunblocks inevitably get washed into the water as you frolic. They also noted that sunblocks these days often contain nanoparticles of titanium dioxide and zinc oxide. When both of these chemicals react with ultraviolet light from sunlight, they form new compounds such as hydrogen peroxide. High levels of hydrogen peroxide could damage the small algae that feed everything from prawns to small fish and even whales. So in theory sunblock could be damaging the ecosystem of coastal waters by significantly reducing these phytoplankton that sit at the bottom of the food chain and which everything above them depends on.

Of course, it is long leap from the stream of theory into the river of reality so the researchers decided on a day (or two) at the beach.

Presumably leaving their lab-coats behind, they joined around 10,000 holidayers on Majorca Island’s Palmira Beach. This Mediterranean beach is popular but it is only a portion of the estimated 200 million tourists that dip themselves into the coastal waters around the Mediterranean each year.

The researchers used laboratory analysis of seawater samples taken throughout the year and correlated them with tourism data. Based on their results, the researchers say they are confident that titanium dioxide from sunblock was largely responsible for a summer spike in hydrogen peroxide levels coastal waters. They also say that this could have potentially dangerous consequences for marine life in the area.

Applying sunblock is well intentioned, but maybe shirts and hats will be better sun protective measures for a majority of the time.