Researchers have detected high levels of sunscreen chemicals in the waters of Shenzhen, China. These include beaches, a harbour, a reservoir, and even tap water. In tests on zebrafish, the team showed that several of these UV filters are being transmitted through the food chain, and can have adverse effects on developing offspring.

Organic UV filters found in sunscreens, skin lotions and make-up, as well as textiles, plastics, and paints, are endocrine disruptors.

 The river and rice fields to the West of Shenzhen

The river and rice fields to the West of Shenzhen, China. Image: Wikimedia Commons 

Risk assessments for single compounds have concluded that current levels of organic UV filters pose low risk, but they don’t account for interactions of mixtures and how these interactions develop over time.

Kelvin Sze-Yin Leung’s team at Hong Kong Baptist University analysed nine common organic UV filters in surface waters of Shenzhen, a city with more than 20 popular beaches. They found seven of the nine chemicals, including benzophenone derivatives BP-3, BP-8, and BP-1, as well as ethylhexyl methoxycinnamate (EHMC), at public beaches, a harbour, a reservoir, and in tap water.

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Total concentrations of UV filters were relatively high at three popular public beaches – ranging from 192 to 645ngL-1 – in the summer as expected. Shenzhen Reservoir showed UV filter pollution in both seasons, while tap water was contaminated by BP-3.

If inefficient water treatment processes are to blame, then research is needed into other ways to remove these filters to protect human health, says Sze-Yin Leung.