Sunscreen’s Environmental Cost
In 2018, the U.S. state of Hawaii banned the sale of sunscreens containing oxybenzone and octinoxate, two of the most commonly used UV blockers. Key West, a city in Florida, and Palau, a small island nation, followed suit with their own bans on the chemicals.
It’s no coincidence these bans were all passed in coastal regions, home to marine environments. Every year, around 14,000 tons of sunscreen wash into the seas, through swimming and showering. As a result, 82,000 chemicals from personal-care products may be present in the oceans. Many of these chemicals, beyond the two banned, contain nanotized particles (less than 100 nanometers in diameter), which helps the cream blend more smoothly onto our skin. These tiny particles can be easily absorbed by aquatic life (corals and fish, specifically) and have negative effects. The National Ocean Service lists out the following chemicals with the potential to harm marine life: Oxybenzone, Benzophenone-1, Benzophenone-8, OD-PABA, 4-Methylbenzylidene camphor, 3-Benzylidene camphor, nano-Titanium dioxide, nano-Zinc oxide, Octinoxate, Octocrylene.
A 2016 study by Downs and colleagues in the journal Archives of Environmental Contamination and Toxicology found that baby coral exposed to oxybenzone and octinoxate showed signs of distress, including coral bleaching (which leaves coral nutrient-deprived and vulnerable to infection), DNA damage, and abnormalities in their growth and skeleton. These findings are reflected in a 2008 study from the journal Environmental Health Perspectives, which found that even at low concentrations, commonly used sunscreen ingredients (including oxybenzone) caused coral bleaching in reefs across the Atlantic, Indian, and Pacific Ocean.
Other studies have found sunscreen ingredients to be harmful to other aquatic animals. The work of environmental toxicology professor Kyungho Choi at Seoul National University has shown that UV filters like benzophenone-3 (BP-3) and octyl methoxycinnamate (OMC) damage reproduction and hormonal balances in fish, as well as their kidney function and neurological behavioural function. A 2014 study from the journal Science of the Total Environment also found that octocrylene might affect brain and liver development in zebrafish. Beyond fish and corals, these chemicals can impair growth and photosynthesis of green algae, induce defects in young mussels, damage the immune and reproductive systems of sea urchins, and accumulate in the tissue of dolphins, which can then be transferred to their offspring.
This damage to marine life comes in conjunction with much greater threats, especially climate change. If we allow this damage to our reefs and underwater animals to continue, we will have lost a vital ecosystem, and a source of income for many around the world.
All that being said, you should absolutely not stop wearing sunscreen, which provides vital protection against sunburns and skin cancer. Even as the summer ends, you can keep these tips in mind. Here are some ways to protect your skin, as well as the oceans:
Cover up: The best way to reduce your sunscreen impact is simply to reduce the amount of exposed skin you need to cover in sunscreen, by wearing UPF (ultraviolet protection factor) sunwear or simply regular clothes.
Avoid aerosols: Aerosols make much of the sunscreen fall to the ground, where it can easily wash into waterways.
Check what’s inside: Make sure to avoid oxybenzone and octinoxate, the chemicals most known to cause environmental harm. Instead, look for mineral (as opposed to chemical) sunscreens that use “non-nano” zinc oxide or titanium dioxide. Don’t rely on a “reef-safe” label, the term is not currently regulated.