Look for Zinc Oxide and Titanium Dioxide.
Avoid Oxybenzone and Octinoxate.
Sunscreen is something we all wear, or are hopefully all wearing, almost every day. Whether it’s in your face moisturizer or you’re lathering up in SPF each morning, sunscreen is one of our essential toiletries. We all rely on sunscreen to protect our skin, but what if the thing that’s supposed to protect us hurts us or our environment?
Unfortunately, that is happening due to some of the chemicals in our sunscreens. Chemicals like Oxybenzone and Octinoxate have been proven to cause harm to us, as well as our environment. When swimmers get in the water wearing sunscreens with these chemicals, they are directly contaminating that water source. The residual sunscreen that hasn’t been absorbed into the skin washes into the water and is usually kicked toward the reefs through swimming actions.
Oxybenzone is found in over 3500 sunscreen products worldwide, making it very common in sunscreens. Oxybenzone is found in many aquatic environments and has been shown to disrupt coral reproduction, cause coral bleaching, and damage coral DNA. Oxybenzone is absorbed through the skin and can be found in urine as quickly as 30 minutes after application, allowing it to bioaccumulate in our bodies. Bioaccumulation is the process of a build-up of certain toxins or chemicals in our bodies that we were exposed to over time; the little bit left behind in our system accumulates until there is a large amount. Oxybenzone has been found in bird eggs, fish, coral, humans, and other marine animals. Oxybenzone can be biomagnified if we eat a fish with high concentrations of oxybenzone, giving us a large amount of that toxic chemical in our body. This is biomagnification, where one predator animal ingests a prey organism with a high concentration of some toxin build up in its body, passing the toxins onto the predator (which could be human) and consuming that prey. Essentially, biomagnification means chemicals like Oxybenzone may increase in concentration in the tissues of organisms as it travels up the food chain. The more Oxybenzone washed into the water, the more likely it is consumed by a smaller organism which is then consumed by a human who has ingested large amounts of a toxin. The abundance of Oxybenzone in our waters makes this more likely; it is found in parts per trillion concentrations off the coast of Barrow, Alaska, U.S.A, to parts per billion on coral reefs in the Caribbean, Pacific, and Red Sea. One of the highest concentrations measured in the marine environment was in Trunk Bay in the U.S. Virgin Islands National Park, St. John Island, U.S. Virgin Islands, where the beach can have up to 5,000 people daily.
Octinoxate is absorbed directly through the skin by applying sunscreens and other personal care products. It has been shown to absorb less into the skin, leaving more to wash into the water. Octinoxate can potentially be stored in the body long-term as fat tissue or in lipid-rich tissue due to it being a fat-soluble chemical. Octinoxate is also at risk of being bioaccumulated in organisms and biomagnified through the food web. A number of aquatic and marine species have been discovered to be contaminated, from carp, catfish, eel, white fish, trout, barb, chub, perch, and mussels to coral, mahi-mahi, dolphins, sea turtle eggs, and migratory bird egg. Octinoxate is also found in large concentrations; in coral reef environments, Octinoxate can reach more than 10 parts per billion. Along the west coast of Maui in 2015, in Hawaii, 11 coral reef sites that were sampled had Octinoxate concentrations from 6.9 parts per trillion to 1,516 parts per trillion.
How does sunscreen end up in marine habitats? Sunscreen can end up in marine habitats in a number of ways.
One way Sunscreen enters the environment is through our shower drains. When we shower off from the day, the residual sunscreen on our skin washes into the water and down the drain, eventually flowing into our oceans.
In our graphic above, we demonstrate how sunscreen can end up in the oceans from our showers. This is only one-way sunscreen ends up in our waterways. Below, take a look at other ways sunscreen washes into our waters.
As one can see from our graphic, residual sunscreen on our skin washes off when we enter the water. On the right, you can see two snorkelers enjoying the view of the reefs below. However, they are unaware that they could be hurting the very reef they are admiring. Our snorkelers above are wearing chemical sunscreens, and as they kick their fins, they are creating a backstream of sunscreen, which they can kick toward the reef like our snorkeler to the left is doing.
Once Sunscreen is in marine environments, how does it affect marine life? We’ve discussed above some of the ways chemical sunscreens can be toxic, but let’s examine how they affect a few other organisms:
What is the solution to the issue of chemical sunscreens? The main solution is to switch to mineral sunscreens instead of chemicals and to use alternative forms of sun protection.
Mineral sunscreens use Zinc Oxide and Titanium Dioxide, both naturally occurring minerals, to reflect UV rays and protect the skin. By reflecting the UV rays, none are absorbed into the skin like in chemical sunscreens.
Zinc Oxide and Titanium Dioxide can reflect both UVA and UVB rays. Some chemical sunscreens are effective against one type of UV rays, either UVA or UVB. The chemicals in chemical sunscreens typically can absorb either one type of UV ray, so more than one chemical is mixed together to form a sunscreen to absorb all UV rays. The graphic to the left demonstrates how UV rays bounce off the skin when they are reflected by mineral sunscreen and how they are absorbed in the absence of sunscreen.
Other reef-safe alternatives for sun protection would be brimmed hats, sun shirts, sun leggings, UV sunglasses, using an umbrella, and seeking shade from 10 AM to 2 PM (prime sun-light hours).
