Japanese firm Kose has confirmed that the seven types of UV protection components commonly used for sun protection do not affect coral growth at environmental concentrations.
This follows collaborative work with Koji Kinjo, an expert in coral cultivation in Okinawa, in which the company built an experimental system using coral bred in a seawater environment where UV protection ingredients are uniformly present. This involved considering numerous parameters to minimise stress on the coral, including the aquarium size, the distance between the samples, water temperature and pH, and managing water flow.
The effects of the ingredients on the coral were tested by emulsifying and dispersing the oil-soluble UV protection agents with a surfactant used in cosmetics. In this way, Kose said, “it was possible to carry out experiments in a form that is close to the uniform dispersion and the outflow from the actual sunscreen”.
Seven UV absorbers - ethylhexyl methoxycinnamate (octinoxate), hexyl diethylaminohydroxybenzoyl benzoate, bisethylhexyloxyphenol methoxyphenyltriazine, polysilicone-15, oxybenzone-3, zinc oxide and titanium oxide – were measured at concentrations higher than the maximum detected in the sea near Okinawa in the past.
After a two-week coral breeding experiment in the presence of each, no abnormalities were found in coral growth in any of the specimens. In addition, no statistically significant difference was confirmed before or after at any level when measuring photosynthetic activity by the chlorophyll fluorescence method.
“From the above, it was confirmed that the seven types of UV protection agents that are widely used as sunscreens do not affect the growth of corals at environmental concentrations,” Kose said. The firm will apply the lessons in the development of coral-friendly UV absorbers.
