Sunscreen is an essential part of our daily routine, protecting our skin from the sun's harmful ultraviolet (UV) rays.

However, while shielding our skin, many sunscreens are inadvertently contributing to the degradation of marine ecosystems, particularly coral reefs.

The very chemicals that protect us can also be harmful to ocean life.

1. The Hidden Dangers of Sunscreen

Many people are unaware that their sunscreen might be harming the ocean. Most sunscreens contain chemical filters like oxybenzone, octinoxate, and octocrylene, which help block UV rays. While effective at protecting human skin, these chemicals can be highly toxic to marine life when they are washed off and enter the water.

Oxybenzone, in particular, is one of the most harmful chemicals to coral reefs. It can cause coral bleaching, a process where corals expel the algae that live in their tissues, leading to a loss of colour and, eventually, the death of the coral.

Even low concentrations of oxybenzone can damage coral DNA, impairing their growth and reproduction. This is especially concerning as coral reefs are critical to the health of marine ecosystems, providing habitat for countless species of fish and other marine organisms.

2. The Science Behind the Damage

Research has shown that sunscreens can have devastating effects on marine life, particularly in popular tourist destinations that use the most sunscreen. When swimmers enter the ocean, sunscreen is washed off and mixed with seawater.

A 2015 study estimated that up to 14,000 tons of sunscreen enter coral reef areas annually, putting significant stress on these delicate ecosystems.

Oxybenzone and other chemical filters act as endocrine disruptors, meaning they interfere with the hormones of marine organisms. For instance, they can cause deformities in young coral, hinder the growth of fish, and impair the reproductive systems of various marine species. This disruption of the natural hormonal balance can lead to population declines, affecting the entire food chain.

These chemicals can persist in the environment long after they have been introduced, leading to a cumulative impact on marine ecosystems. This persistence is particularly troubling in areas where water circulation is limited, such as coral lagoons, where the concentration of harmful chemicals can become particularly high.

3. Sunscreen Pollution: A Global Issue

Sunscreen pollution is a global problem, but it is most pronounced in areas with heavy tourism. Coral reefs in popular vacation spots, such as Hawaii, the Caribbean, and the Great Barrier Reef, are among the most affected.

The problem has become so severe that some regions have taken legislative action. In 2018, Hawaii became the first U.S. state to ban the sale of sunscreens containing oxybenzone and octinoxate, a move followed by other locations such as Palau and certain areas in Mexico.

These bans are a step in the right direction, but they are not a complete solution. Sunscreen pollution is not limited to tourist-heavy areas; it can affect marine environments worldwide. Even inland water systems can carry these chemicals to the ocean through rivers and streams.

4. What You Can Do

While the issue of sunscreen pollution may seem daunting, there are steps individuals can take to reduce their impact on the ocean. One of the most effective actions is to choose reef-safe sunscreens.

These sunscreens are formulated without harmful chemical filters, instead using mineral-based ingredients like zinc oxide and titanium dioxide. These minerals create a physical barrier on the skin that reflects UV rays without causing harm to marine life.

When selecting a sunscreen, look for labels that say "reef-safe" or "ocean-friendly." However, it's essential to be cautious, as some products may still contain harmful ingredients despite these claims. Reading the ingredient list is the best way to ensure that your sunscreen is truly safe for the environment.

In addition to choosing the right sunscreen, consider wearing protective clothing, such as long-sleeved shirts, hats, and sunglasses, to reduce the amount of sunscreen needed. This not only minimizes your impact on the ocean but also provides better protection against the sun.

Reducing overall sun exposure by seeking shade during peak sunlight hours (10 a.m. to 4 p.m.) can also help. This simple practice reduces the need for sunscreen and lowers your risk of sunburn and skin damage.