Sunscreen's Impact: Ocean Pollution And Environmental Harm

Sunscreen is a vital tool in protecting ourselves from the sun's harmful ultraviolet rays. However, the very products designed to safeguard our health may be causing significant harm to the world's waterways and marine life. Sunscreen pollution is an increasingly prominent issue, with evidence suggesting that sunscreen chemicals are damaging marine ecosystems, particularly coral reefs. Sunscreen enters the water through various means, including washing off swimmers' skin, sewage treatment plant outflows, and wastewater from showers and sinks. This pollution has been found to impair the growth of marine life, induce coral bleaching, and even cause deformities and reproductive issues in aquatic organisms. With the growing popularity of sunscreen products and coastal tourism, addressing sunscreen pollution is crucial to protecting the health of our aquatic environments.

Sunscreen chemicals are harmful to coral reefs

Coral reefs are incredibly valuable ecosystems that provide billions of dollars in economic and environmental services, such as food, coastal protection, and tourism. However, they face serious threats from climate change, unsustainable fishing, land-based pollution, coastal development, disease, and invasive species.

In recent years, scientists have discovered that some of the chemicals found in sunscreens and other personal care products also threaten the health of coral reefs. These products can enter waterways when swimmers jump into the ocean, rivers, and lakes, or through wastewater runoff. It is estimated that approximately 14,000 tons of sunscreen enter waterways globally each year.

Sunscreens that use chemical UV filters are of particular concern. These filters absorb UV rays and turn them into heat that is released from the skin. When these chemicals enter the water, they can accumulate in the tissues of coral, mussels, sea urchins, fish, and dolphins. This accumulation can induce coral bleaching, damage DNA, deform young, and even kill. Specifically, oxybenzone, octinoxate, benzophenone-1, benzophenone-8, OD-PABA, 4-Methylbenzylidene camphor, 3-Benzylidene camphor, nano-Titanium dioxide, nano-Zinc oxide, and octocrylene have been identified as harmful to marine life.

To protect coral reefs, it is recommended to use sunscreens with physical UV filters, such as zinc oxide and titanium dioxide, which form a physical block to shield the skin from absorbing UV rays. "Reef-friendly" or "reef-safe" products that do not contain harmful chemicals are also preferable. However, it is important to note that the term "reef-friendly" is not regulated, so checking the "active ingredients" label is essential. Additionally, using micro-sized (or non-nano) mineral sunscreens can help avoid the toxic effects of nanoparticles.

Sewage treatment plants do not remove sunscreen chemicals

Sunscreen is a staple for many of us during the summer months, but what happens when we wash it off? Do sewage treatment plants remove the chemicals from our sunscreens? Unfortunately not.

When we wash off sunscreen, whether in the shower or in the sea, the chemicals from the lotion enter our waterways. This is a problem because sewage treatment plants do not filter out the chemicals or microplastics found in personal care products. This means that these chemicals can accumulate in the water, causing potential harm to the environment.

For example, triclosan, found in hand sanitizers, acts as an endocrine disruptor in fish. Butylated hydroxytoluene (BHT), a preservative in many personal care products, can bioaccumulate to toxic levels in marine organisms. Oxybenzone, a common UV-blocking chemical in sunscreen, has been found to cause mortality in corals even at low concentrations.

These chemicals can also have detrimental effects on other marine life, such as mussels, sea urchins, fish, and dolphins. They can induce defects in young mussels and impair the immune and reproductive systems of sea urchins. In fish, they can decrease fertility and reproduction and cause female characteristics to appear in male fish.

The impact of sunscreen chemicals on the environment is an active area of research, and organizations like NOAA are working to understand the ecological risks associated with these chemicals. In the meantime, it is essential to be mindful of the potential impact of these products on the environment and to dispose of them responsibly.

Sunscreen ingredients are absorbed through the skin and enter waterways

Sunscreen is a crucial tool in protecting ourselves from the sun's harmful ultraviolet UV rays. However, the very chemicals that protect us from UV rays can be harmful to aquatic life when they enter our waterways.

Sunscreen can enter waterways in several ways. One way is through "swimmer pollution," where sunscreen washes off swimmers' skin and directly into the water. Sunscreen can also enter waterways indirectly when swimmers shower or wash it off their bodies at home. In both cases, the sunscreen and its ingredients end up in the water, potentially harming marine life.

It is important to note that not all sunscreens are created equal in this regard. Mineral sunscreens, which reflect UV rays, are considered a better option for the environment as they have fewer effects on aquatic organisms. Chemical sunscreens, on the other hand, are designed to be absorbed into the skin and have been found to enter the bloodstream. These chemical sunscreens have now been confirmed to wash off with sweat and water, entering our waterways and potentially causing harm.

A study by the US Food and Drug Administration (FDA) found that six active ingredients commonly found in chemical sunscreens penetrate the skin and absorb into the blood plasma. These ingredients include avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate. The study participants applied the sunscreens over 75% of their bodies, and all six ingredients reached blood concentrations exceeding the FDA threshold for additional safety testing after just one application. This finding highlights the need for further industry testing to determine the safety and effects of chronic exposure to these ingredients.

The impact of sunscreen ingredients on aquatic life is a serious concern. For example, oxybenzone, a common UV-blocking chemical in sunscreen, has been found to induce bleaching and damage the DNA of coral reefs. Other chemicals in sunscreen can impair the growth and photosynthesis of green algae, damage the immune and reproductive systems of sea urchins, and decrease the fertility and reproduction of fish, even causing female characteristics in male fish. These chemicals can also accumulate in the tissues of dolphins and be transferred to their young.

Oxybenzone induces coral bleaching and is genotoxic

Oxybenzone, also known as benzophenone-3, is a common ultraviolet-blocking chemical found in sunscreens. It has been identified as environmentally harmful, particularly to coral reefs. Oxybenzone is known to induce coral bleaching and cause genotoxicity, which are detrimental to the health and survival of coral ecosystems.

Coral bleaching occurs when oxybenzone lowers the temperature at which corals bleach when exposed to prolonged heat stress. This means that corals can bleach at lower temperatures in the presence of oxybenzone. Studies have shown a direct relationship between the concentration of oxybenzone and the degree of coral bleaching, with higher oxybenzone levels resulting in more severe bleaching. Although oxybenzone is harmful under all light conditions, its effects are stronger when exposed to light.

The mechanism behind coral bleaching induced by oxybenzone involves its impact on the symbiotic microalgae that corals rely on for nutrition. Oxybenzone can activate latent viral infections in these microalgae, disrupting the coral's source of nutrition. Additionally, oxybenzone has been found to be genotoxic, meaning it damages the DNA of corals and induces severe and lethal deformities. This genetic damage can impair the corals' ability to reproduce and pass on healthy genetic material to future generations, further threatening the survival of coral populations.

The presence of oxybenzone in coral ecosystems can also accelerate coral mortality when combined with other stressors, such as elevated temperatures. In studies, oxybenzone and heat stress have been shown to significantly impact the photosynthetic yield in coral species, causing a decrease in their ability to photosynthesize and survive. The combination of oxybenzone exposure and elevated temperatures can alter the abundance of bacterial families in the coral microbiome, further weakening the corals and making them more susceptible to global warming and other environmental stressors.

The use of oxybenzone-containing sunscreens contributes to "swimmer pollution," which threatens coral reefs worldwide. When swimmers enter the water with sunscreen on their skin, the oxybenzone can wash off and enter the surrounding waters, affecting the nearby coral reefs. This pollution is particularly inevitable in areas without sophisticated sewage treatment and management systems, as the chemicals from sunscreen can enter the sewer and eventually reach the ocean.

Mineral sunscreens are considered a better option

Sunscreen is an essential product for protecting our skin from the sun's harmful ultraviolet (UV) rays. However, the chemicals in traditional sunscreens can have detrimental effects on the environment, especially fragile marine ecosystems such as coral reefs. As a result, mineral sunscreens are considered a better option for both personal and environmental health.

Mineral sunscreens, unlike traditional chemical sunscreens, do not use UV filters that can harm aquatic life. Chemical UV filters such as oxybenzone, benzophenones, and OD-PABA are linked to various issues in marine organisms, including coral bleaching, DNA damage, impaired growth, and reproductive issues. These chemicals can enter waterways through ""swimmer pollution," when sunscreen washes off swimmers' skin, and through sewage systems when people shower or wash off sunscreen. By avoiding these chemical UV filters, mineral sunscreens reduce the impact on aquatic ecosystems.

Mineral sunscreens typically contain ingredients like zinc oxide and titanium dioxide, which are minerals that sit on top of the skin to block UV rays. These minerals are generally considered safe for the environment and do not pose the same level of risk to aquatic organisms as chemical UV filters. However, it is important to ensure that these minerals are not in their nanoparticle form, as nanoparticles can be absorbed by the skin and potentially cause internal complications. Non-nano mineral sunscreens provide effective sun protection while minimizing the risk of environmental and health concerns associated with nanoparticles.

Another advantage of mineral sunscreens is their longer-lasting protection. Mineral sunscreens remain on the skin for extended periods, reducing the frequency of reapplication. This not only provides better protection against sunburn but also reduces the amount of sunscreen that washes off into the water, minimizing the potential impact on aquatic life.

While mineral sunscreens are a more environmentally friendly option, it is worth noting that even mineral sunscreens can have some impact on the environment. For example, preliminary research has shown that zinc oxide sunscreen can affect the development of sea urchin embryos. Therefore, while mineral sunscreens are a better choice, further research is needed to fully understand their effects on different marine organisms.

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