Liquid crystal monomers (LCMs), essential for the functioning of laptop, television, and smartphone screens, are now being detected in marine life, raising alarms about their environmental impact. A study published in ACS’ Environmental Science & Technology highlights the presence of these persistent pollutants in the tissues of dolphins and porpoises, including critical areas such as the brain, suggesting their ability to cross the blood-brain barrier.
“Our research reveals that LCMs from everyday electronics are not just pollution — they’re accumulating in the brains of endangered dolphins and porpoises,” said Yuhe He, a researcher at City University of Hong Kong and a corresponding author of the study. “This is a wake-up call: The chemicals powering our devices are now infiltrating marine life, and we must act now on e-waste to protect ocean health and, ultimately, ourselves.”
The Ubiquity of LCMs and Their Path to the Ocean
LCMs are responsible for controlling light passage in display screens, creating the vivid images that consumers demand. Due to the widespread use of electronic devices, these chemicals have been detected in indoor air, dust, and wastewater, eventually finding their way into coastal ecosystems. While previous studies have linked some LCMs to health risks in humans and aquatic species, their movement through marine food chains and impact on top predators remained less understood until now.
To explore this, researchers, including Bo Liang and Yuhe He, analyzed tissue samples from Indo-Pacific humpback dolphins and finless porpoises collected between 2007 and 2021 in the South China Sea, a crucial habitat for these endangered species. The study screened various tissues, including blubber, muscle, liver, kidney, and brain, for 62 individual LCMs.
Key Findings: LCMs in Marine Mammals
The analysis revealed that four compounds accounted for most of the detected LCMs. Prior research identified similar LCMs in the fish and invertebrates consumed by these dolphins and porpoises, indicating that the pollutants likely enter through their diet rather than directly from the water.
“Most of the LCMs found in dolphins and porpoises likely originated from television and computer screens, with smaller contributions from smartphones.”
Although blubber, a fatty tissue known for storing pollutants, showed the highest concentration of contaminants, the presence of LCMs in other organs, particularly the brain, was unexpected. This discovery points to potential health hazards, including neurotoxic risks for these marine mammals.
Implications and Calls for Action
LCM levels in porpoise blubber have fluctuated over time, generally increasing with the rise of liquid crystal display use and then declining as manufacturers transition to LED displays. However, the persistence of these compounds in the environment remains a concern.
Further laboratory tests demonstrated that several common LCMs, including the major four found in the samples, altered gene activity related to DNA repair and cell division in cultured dolphin cells. These findings suggest that LCM pollution could have detrimental effects on marine mammals, prompting researchers to advocate for further investigation and regulatory measures.
“The researchers call for urgent regulatory action and improved e-waste disposal to mitigate the impact of LCM pollution on wildlife.”
Funding and Future Research Directions
The study was supported by various organizations, including the National Natural Science Foundation of China, Research Grants Council of Hong Kong, and several other regional and international bodies. The authors emphasize the need for continued research to fully understand the long-term effects of LCMs on marine ecosystems and to develop effective strategies for e-waste management.
The paper’s abstract will be available on February 25 at 8 a.m. Eastern time at the following link: ACS Publications.
