Sunscreen is designed to protect our skin from harmful UV rays to prevent skin cancer, but could it be damaging our health and the planet in the process?
Despite sunscreen being now universally accepted as a critical barrier to reducing skin cancer risk, in recent years, it has come under scrutiny for being potentially toxic to the environment – especially the ocean.
Across the world, every day, millions of people are applying chemicals to their skin and if they enter the ocean, residues from these products seep into the marine environment. There are no hard and fast statistics on the volume of sunscreen entering our seas but scientists estimate it is approximately 14,000 tons.
There are two main types of sunscreens: chemical sunscreens and mineral sunscreens. Alarm bells have been raised by the inclusion of ultraviolet filters oxybenzone and octinoxate, which are found in chemical sunscreens, although other troubling ingredients exist.
- Chemical sunscreens comprise chemicals that absorb the UV rays from the sun rather than allowing your skin to absorb those rays.
- Mineral sunscreens include zinc oxide and titanium dioxide, both of which are white. Mineral sunscreen leaves a white tint on your skin. Because sunlight bounces off white pigments, mineral sunscreens act as a physical barrier, reflecting the sunlight away from your skin before it can absorb it.
Oxybenzone, a common ingredient in over 3,500 sunscreen lotions and personal care products, has been shown to have detrimental effects on marine environments. The most significant impact has been on coral reefs.
When you swim with sunscreen, chemicals like oxybenzone can seep into the water, where corals absorb them. These substances contain nanoparticles that can disrupt coral reproduction and growth cycles, leading to bleaching.
Coral reefs have developed a unique symbiotic relationship with algae - known as zooxanthellae - that coexist inside the corals. These algae give the corals vibrant colouration, provide oxygen and remove waste. The presence of oxybenzone in the water is toxic to the coral and is a stressful environment for their symbiotic partners. This stress can awaken dormant viral infections within the algae that trigger the coral to expel the algae. Without the algae, the coral turns white. This process is known as bleaching.
Bleaching not only makes the coral less attractive but also makes them more susceptible to diseases. Even worse, oxybenzone is a photo-toxicant, which means exposing the chemical to light intensifies its adverse effect.
Even if you don't swim after applying sunscreen, it can go down drains when you shower. In addition, aerosol versions of sunscreen can spray large amounts of the product onto the sand, where it gets washed into our oceans.
Coral reefs are often described as the tropical rainforests of the sea, buzzing with life like an underwater city. They are home to 25% of known marine life; these ocean ecosystems cover around 0.1% of the planet's surface.
Oxybenzone damages the DNA of corals, too - it is a genotoxicant. Ultimately, this kills the coral's offspring, known as planulae, and has subsequent impacts on the future of coral. Oxybenzone does this by disrupting the planulae's hormones responsible for the development of its skeleton.
Remarkably, oxybenzone has even been shown to result in gender shifts within some fish species, causing males to develop female attributes and females to undergo reduced egg production.
Harmful to Human Health
Scientists do not fully understand the effects of oxybenzone on human health. There is limited research on the quantities of these chemicals we are ingesting and how much ends up in the environment after spending a day in the sun.
Oxybenzone and octinoxate may be assimilated by the body and have been found in everything from human urine to breast milk. Nanoparticles of titanium dioxide and zinc oxide are frequently used in sunscreens to avoid a visible film and boost SPF protection because they directly absorb sunlight. Still, some scientists have called for more clinical studies to determine whether these tiny particles enter the bloodstream.
Although there is no conclusive evidence linking oxybenzone, octinoxate, nano titanium dioxide and nano zinc oxide to severe health impacts in humans, there is a convincing case building.
Another issue with oxybenzone is that it reacts with chlorine, which is typically used for pool sanitation and water treatment plants to remove toxins. Chlorine and oxybenzone react to form chloroform with higher levels of genotoxicity than oxybenzone alone.
What Can You Do?
- Read the Ingredients: Check out what's inside before stocking up on chemical-laden sun protection. Avoid ingredients like oxybenzone and instead, gravitate towards ingredients like zinc oxide or titanium oxide.
- Shy Away from Spray: Go for the cream if you must pick between lotion or aerosol spray. As convenient as sprays may be, many aerosol spray contents miss our bodies and land on the sand, much of which ends up in the ocean.
- Wear UV Protected Clothing: Wearing shirts, hats or pants with UV protection can reduce the amount of sunscreen you apply by 90%. For optimal sun protection, stock up on UV protected clothing.
Some destinations, such as Hawaii and Palau, have introduced bans on harmful sunscreens; these bans will come in to effect in the coming years.
What About Reef Safe Sunscreen?
It's increasingly common to see brands advertising themselves as "reef safe". Although these sunscreens often do not include oxybenzone and other harmful chemicals, they are not always safe for ocean life. Despite some sunscreens being less toxic than others, the "reef safe" labelling is not currently regulated. Sunscreens containing non-nano zinc oxide, for example, are generally considered safe for the environment.