By: Themis Yining Chen
Updated March 25, 2026
HONG KONG – Hong Kong researcher Yuhe He has raised the alarm that chemicals in everyday electronics’ screens which can harm human health may also impact the health of marine mammals.
Henry Yuhe He, a professor at City University of Hong Kong, said a growing body of research shows that liquid crystal monomers, or LCMs, used in LCD screens for smartphones, computer monitors and televisions, can leak into the environment when devices are discarded and processed as waste.
LCMs, liquid crystal monomers, are a class of organic compounds widely used in the manufacturing of liquid crystal displays for electronic products. They function to create “micro-blinds” in screen devices, assisting in the ability of a viewer to clearly see different colors and images on the screen.
But in a study published earlier this year, He and his team reported that LCMs from discarded electronics can be released into the environment, then enter human living spaces and food chains. The chemicals are able to cross the blood-brain barrier, a protective system found in both humans and marine mammals that normally prevents harmful substances from reaching the brain, He found.
“The special concern with these chemicals is that they can penetrate the blood-brain barrier and damage the nervous system in mammals and humans,” He said.
A number of major media outlets such as The Guardian and the South China Morning Post have also reported on the significance of He’s findings and the potential impact of these chemicals on marine life.
In an earlier study, based on samples from 112 residents of eastern China, He found LCMs present in humans, leading to concerns about cell and DNA damage from these chemicals. A follow-up project has now found that LCMs can accumulate in the brains of dolphins and finless porpoises, disrupting cell function and potentially leading to death, He said.
Of 62 types of LCMs screened, 38 were detected in tissue samples from Indo-Pacific humpback dolphins (more commonly referred to as “white” or “pink” dolphins) and finless porpoises in the South China Sea. Most of the contamination could be traced to television and computer screens, with a smaller portion linked to smartphones, according to He. If the screens have been broken in the discarding process, it can be even more serious, He said.
“Damaged screens can release even more LCMs,” He said.
According to the Global E-Waste Monitor Report, a United Nations backed investigation, illegal transportation, dumping and improper treatment of e-waste is common in parts of Asia and can result in environmental and health impacts. This waste can be incinerated or landfilled without recycling — and if regulations or their enforcement on waste management in a country or region is lax — harmful toxins from them can eventually leach into the sea.
Local environmental groups say Hong Kong’s coastal waters and aquatic life are already under pressure. According to a report by conservation group Park & Trails, sightings of white dolphins in Hong Kong waters have dropped sharply since 2014. Both the WWF Hong Kong and the city’s Agriculture, Fisheries, and Conservation Department say that numbers of the marine mammals in Hong Kong waters have fallen by more than 80% over the last two decades.
Marine debris from daily human activities and habitat degradation from offshore operations and pollutants have long been seen as a major cause of dolphin deaths.
Viena Mak Hei-man, vice chair of the Hong Kong Dolphin Conservation Society, said Chinese white dolphins and finless porpoises have been two of the most commonly seen wild marine mammal species in Hong Kong — but a number of factors are converging to put pressure on the creatures.
“With the drastic shrinkage of the Chinese white dolphin’s habitat in Hong Kong, they are suffering from water pollution, underwater noise and other impacts,” Mak said.
The LCM researcher, He, said the spread of liquid crystal displays coincided with rising levels of these pollutants in dolphins.
“With the proliferation of LCD screens, the levels of these contaminants in dolphins has increased,” He said. “Although in recent years the levels have begun to decline as new LED technologies become more common, the toxicity of the corresponding luminescent materials remains unknown, and the potential risks cannot be ignored.”
He added that the issue is not only about protecting ocean creatures but also about safeguarding human health, as the chemicals could come back to harm people through consumption of affected marine life.
“We must remember that pollution eventually cycles back to humans,” He said. “People may be exposed to these chemicals through eating seafood.”
He said both individuals and governments can help reduce the threat.
“For individuals, the most effective action is to extend the life of electronic products as much as possible and to hand them over to certified e-waste recyclers rather than simply throwing them in the bin,” He said. “Governments also need to introduce stricter regulations to control the market and industry and reduce the flow of electronic waste.”
Additional editing and writing by: John H. Noonan