According to Prof Dr Karl Fent, who presented the research at today's cometic science conference at in-cosmetics, the levels of some chemicals that lead to disruptions in the hormonal system of fish are not much higher than those found in the lakes and rivers of Switzerland.
'For some compounds such as 3BC the margin of safety is very low,' he said.
Fent's work looks at organic filters such as 3BC (3-benzylidene camphor) that absorb UV rays rather then reflecting them like titanium dioxide and zinc oxide.
Such filters can enter an aquatic environment either directly from wash off from user's body, clothing and towels, or pass by a water treatment plant, he explained.
Concentrations vary in rivers and lakes
The concentrations that his team found in the rivers and lakes of Switzerland vary and can be affected by factors such as their proximity to waste water outlets, he said.
After extablishing that UV filters are 'everywhere' in the environment, Fent's team set about investigating the effect their presence might have on the aquatic ecosystem.
They performed a number of tests in fish (using fat head minnows as they have easily identifiable secondary sexual characteristics) to look at the effects of different concentrations of the filters.
All 18 of the UV filters tested illustrated some hormonal activity in the fish, but at very different concentrations, explained Fent.
The filters BP1, BP2, 3BC and Et-PABA all lead to the induction of vitellogenin, a protein released by fish when they are ovulating, and 3BC and BP2 also lead to the feminization in secondary characteristics of male fish.
3BC is a concern
For Fent, the most worrying is 3BC as effects occurred even when the filter was present in extremely low concentrations (as low as 3 μg/L).
Furthermore, he explained that the effects of more than one estrogenic compound in the system, which is undoubtedly the case today, are unknown.
When challenged by the conference chair regarding the presence of endocrine disruptors in other products such as some forms of contraceptives, Fent said that UV filters were obviously only part of the problem.
'UV filters are not the most potent ones; but they are adding to the problem,' he said.