The daily use of sunscreen bearing an SPF of 15 or higher is widely acknowledged as essential to skin cancer prevention, not to mention skin damage associated with aging. Though this sunscreen may be very good for us, it may be very bad for the environment, a new Tel Aviv University study finds. New research published in Archives of Environmental Contamination and Toxicology finds that a common chemical in sunscreen lotions and other cosmetic products poses an existential threat -- even in miniscule concentrations -- to the planet's corals and coral reefs. "The chemical, oxybenzone (benzophenone-3), is found in more than 3,500 sunscreen products worldwide. It pollutes coral reefs via swimmers who wear sunscreen or wastewater discharges from municipal sewage outfalls and coastal septic systems," said Dr. Omri Bronstein of TAU's Department of Zoology, one of the principal researchers.

The study was conducted by a team of marine scientists from TAU, including Prof. Yossi Loya, also of the Department of Zoology, the Haereticus Environmental Laboratory in Virginia, the National Aquarium (US), the US. National Oceanic & Atmospheric Administration, Ben Gurion University of the Negev, and other labs in the US. 

A deadly day at the beach

A person spending the day at the beach might use between two to four ounces of sunblock if reapplied every two hours after swimming, towelling off, or sweating a significant amount. Multiply this by the number of swimmers in the water, and a serious risk to the environment emerges.

"Oxybenzone pollution predominantly occurs in swimming areas, but it also occurs on reefs 5-20 miles from the coastline as a result of submarine freshwater seeps that can be contaminated with sewage," said Dr. Bronstein, who conducted exposure experiments on coral embryos at the Inter University Institute in Eilat together with Dr. Craig Downs of the Heretics Environmental Laboratories. "The chemical is highly toxic to juvenile corals. We found four major forms of toxicity associated with exposure of baby corals to this chemical."