The Hidden Cost of Sunscreen: Protecting Our Skin Without Harming Marine Life

Summer and sunshine go hand in hand, bringing with them countless benefits for both our physical and mental well-being. From boosting vitamin D production to improving our mood, spending time in the sun is one of the pleasures many of us look forward to after long, dark winters. Yet while protecting our skin from harmful UV rays is essential, growing evidence suggests that some of the products we rely on most may be having unintended consequences beneath the waves. As concerns about skin cancer rise alongside new research into sunscreen pollution, it is becoming increasingly important to understand how we can safeguard both our health and the health of our oceans.

Summer: A Boom of Vitamins

Summer is approaching, and with it, our desire to spend more days in the sun, enjoying its warm rays on our skin after months of darkness and rain. The perks of sun exposure are countless, and vitamin D is among the best-known.

Unlike most vitamins, which we have to get from food, our bodies can actually make vitamin D when our skin is exposed to sunlight. Sunlight triggers a reaction in the skin that creates vitamin D, but how much we produce depends on how much UVB light reaches our skin. Wearing more clothes, using sunscreen, and having darker skin (more melanin) all mean less vitamin D is made. For example, if a fair-skinned person spends about 30 minutes in the summer sun wearing a bathing suit, their body can make up to 50,000 IU (1.25 mg) of vitamin D in a day. People with tanned or darker skin will still make vitamin D, but their bodies might produce less in the same amount of time, about 20,000–30,000 IU for tanned skin and 8,000 – 10,000 IU for dark skin.

But the benefits of lying in the sun are not merely physical; they are also psychological. The fact that the sun makes us happier is not just a myth; research shows that not getting enough vitamin D has been linked to a higher risk of depression, and taking vitamin D supplements might help people who are struggling with depression. But for most of us, sunlight remains the primary source of vitamin D, so getting enough sun can play a role in our mental health.

However, sun exposure – though overall beneficial and enjoyable – can quickly turn dangerous if done excessively and unprotected.

Why Sunscreen Matters

Worryingly, recent studies prove that skin cancers like melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) are becoming more common worldwide, affecting people differently depending on where they live.

Unfortunately, the number of new cases and the impact on people’s lives are expected to increase dramatically by 2050, especially in countries with lower income and fewer healthcare resources. Experts predict that, by then, the number of years of healthy life lost because of melanoma could jump from about 2 million in 2025 to over 3.3 million. For squamous cell carcinoma, that number might go from 1.2 million to 4 million. Basal cell carcinoma is expected to have the biggest impact, with nearly 5 million years of healthy life lost by 2050. The worst increases are likely to happen in countries with less money and fewer resources.

Sunscreen lotions have always been among the most effective precautions we can take to protect ourselves from sun damage while enjoying our long-awaited summers.

Sunscreen’s Environmentally Degrading Legacy

A new study finds that at least a quarter of the sunscreen we apply washes off when we swim in the sea. On a busy beach with 1,000 people, that adds up to more than 35 kilograms of sunscreen ending up in the water every day.

Sunscreens use two main types of ingredients: chemical (organic) and mineral (inorganic or metal-based). Chemical filters are made from dozens of different compounds and work by absorbing the sun’s UV rays. Mineral filters, like titanium dioxide and zinc oxide – which are sometimes called “reef safe” – work differently: they reflect or scatter UV rays away from the skin.

The experts involved call major attention to benzophenones (BPs); the most widely used UV filters in sunscreens, with fourteen different types found in personal care products. These chemicals can build up in the environment and in living things, and they don’t break down easily. One type, called benzophenone-3 or oxybenzone, is now on the European Chemical Agency’s watch list because it is being investigated for possibly disrupting hormones.

The Effects of Sunscreen on Aquatic Wildlife

The latest evidence from the National Academy of Science is disturbing, to say the least.

Sunscreen chemicals can affect marine life in different ways:

• Green algae: Their growth and ability to make food through photosynthesis can be harmed.
• Coral: These chemicals can build up in coral tissues. They may cause coral bleaching, damage DNA, harm young corals, and can even be deadly.
• Mussels: They can cause birth defects in baby mussels.
• Sea urchins: They can weaken the immune system, interfere with reproduction, and cause deformities in young sea urchins.
• Fish: Exposure can lower fertility, reduce reproductive capacity, and sometimes cause male fish to develop female traits.
• Dolphins: These chemicals can build up in dolphin tissues and even be passed on to their young.