Scientists detect sunscreen chemicals that can lead to birth defects and infertility

A team of scientists from the Hong Kong Baptist University (HKBU) has detected in sunscreen chemicals that can cause birth defects and infertility. In their study, they discovered that chemicals in sunscreens caused abnormalities in zebrafish and killed their offspring.

After human use, organic or chemical ultraviolet (UV) filters of sunscreens are discharged into the sea, either directly by washing with seawater, or indirectly through the discharge of wastewater. Eventually, they enter the sea, posing a threat to marine organisms and the ecosystem.

The researchers said that these UV filters could eventually transmit the food chain to humans and affect our health.

"UV rays increase the risk of premature aging of the skin, freckles and trigger skin cancer. Organic or chemical UV filters capable of absorbing or blocking UV rays are widely used in personal care products, including sunscreens, "said Kelvin Leung Sze-yin, associate professor at HKBU.

"Given that more than 70% of the genetic structure of zebrafish resembles that of humans, the effects of these contaminants transmitted by the food chain to humans and the long-term impact about human fertility can not be neglected, "added Sze-yin.

In the study, reported in the journal Environmental Science and Technology, the team simulated the real aquatic environment in a laboratory where contaminated artemia was fed to zebrafish for 47 days. Contaminated water contained three commonly used UV filters, namely benzophenone-3 (BP-3), ethylhexyl methoxycinnamate (EHMC) and octocrylene (OC).

After 47 days, no adult zebrafish appeared to have been damaged, but many of their embryos had malformations or abnormalities.

The 24-hour embryo mortality rate has increased significantly from 10% to almost 60%, while the 72-hour hatching rate has decreased significantly from 80% to less than 30%.

Sze-yin said the combined presence of BP-3, EHMC and OC creates a "mixing effect" that increases their build-up compared to the case where only one chemical is present.

Sze-yin called for a regulation to cover the use of chemicals in personal care products and said that there should be further research on the long-term impact of these contaminants. He recommended the use of natural sunscreens based on minerals.