Sunscreen Stresses Coral Reefs

May 23, 2008 -- Sunscreen lotions used by beach-going tourists worldwide are a major cause of coral bleaching, according to a new study commissioned by the European Commission.

In experiments, the cream-based ultra-violet (UV) filters -- used to protect skin from the harmful effects of sun exposure -- caused bleaching of coral reefs even in small quantities, the study found.

Coral reefs are among the most biologically productive and diverse of ecosystems, and directly sustain half a billion people. But some 60 percent of these reef systems are threatened by a deadly combination of climate change, industrial pollution and excess UV radiation.

The new study, published in U.S. journal Environmental Health Perspectives, has now added sun screens to the list of damaging agents, and estimates that up to 10 percent of the world's reefs are at risk of sunscreen-induced coral bleaching.

Chemical compounds in sunscreen and other personal skin care products have been detected near both sea and freshwater tourist areas. Previous research has shown that these chemicals can accumulate in aquatic animals, and biodegrade into toxic by-products.

Researchers led by Roberto Danovaro at the University of Pisa in Italy added controlled amounts of three brands of sunscreen to seawater surrounding coral reefs in Mexico, Indonesia, Thailand and Egypt.