It's a hot summer's day and you're at the beach for a well deserved day of leisure, enjoying the refreshing water and a picnic. There is very little shade, so you slather on the sunscreen, unaware that you might be negatively impacting nearby fish.
Sunscreen works by either absorbing or reflecting ultra violet (UV) radiation. Sunscreens are highly recommended to help prevent sun-induced skin cancers, which can be some of the most aggressive cancers in humans. It might surprise you to learn that most of the ingredients used in most sunscreens have not yet been tested for safety. The sunscreen market was estimated to be worth over $1 billion in the USA alone (2004 figures).
Read the ingredient list of your average sunscreen product, and all you get out of it is a list of chemicals - if you can find any ingredients! You don't worry about these chemicals because the products are supposed to have been tested before being sold to consumers. Furthermore, you are told ad nauseum to use sunscreen to prevent cancer.
The one place that you are most likely to use sunscreen is when you are spending time in and beside water outdoors, whether that's the local outdoor swimming pool, a pond, a lake or river, or the ocean. Even if you couldn't care less about protecting yourself from skin cancer, you know that sunburns obtained while on the water are brutal.
One of the key ingredients in most commercial sunscreens is a chemical commonly known as 'oxybenzone.' Oxybenzone was last tested for safety in the USA in the 1970's. It has been linked to allergic reactions in some people. More recently, studies have shown that oxybenzone is absorbed by human bodies and has been found in urine samples. Oxybenzone not only penetrates the skin and enters your blood stream, it is also photosensitive and while studies have not yet been conducted, it is believed that oxybenzone behaves like it's related chemical, benzophelnone, which attacks DNA when illuminated.
Another ingredient, PABA, is also a concern, although again, studies on its effects are lacking. You will notice, however, that PABA is not put into sunscreen products meant for babies and young children. The PABA you will find in sunscreen lotion is not the same as the PABA your body extracts from vegetables, plants and eggs.
Recent studies on oxybenzone (2004) have found that oxybenzone is released into the water by swimmers and also through laundry activities. Poiger, et al, found oxybenzone in surface water in "concentrations that indicate a potential for bioaccumulation."
Yes, bioaccumulation. This is not an encouraging word, especially in relation to sunscreens. Here you are, trying to protect yourself from cancer, not create sex changes in other species! But that's exactly what scientists are concluding is the result of oxybenzone exposure in some species of fish that feed near sewage outlets, mainly turbot and sole. It seems that oxybenzone mimics oestrogen in fish species, causing male fish to turn into females. The future impacts on some fisheries could be devastating.
Fish are a very important animal to humans. We have farmed fish (aquaculture) for at least 3,000 years . The value of aquaculture activities is estimated at over $1.13 billion a year in the USA. It is uncertain what the effects of oxybenzone might be on farmed fish, or other species of wild fish. Nor is it known what effect(s) might arise from the combination of oxybenzone with other chemicals found in places such as the Great Lakes. Once again human activities are impacting the environment in a negative fashion. However, it seems that due to the importance of fish, this issue might be addressed quickly.