Chinese White Dolphin (Sousa chinensis chinensis) . Credit: Takoradee
Liquid crystal monomers (LCMs) are critical components of many electronics, like laptops, televisions and smartphones. However, they are also considered environmental pollutants.
Researchers in China are sounding the alarm on the pollutants as a recent study found them in dolphin and porpoise tissues, including blubber, muscle and brain—demonstrating their ability to cross the blood-brain barrier.
For the study, published in ACS’ Environmental Science & Technology, analyzed tissue samples from Indo-Pacific humpback dolphins and finless porpoises collected between 2007 and 2021 in the South China Sea, an important habitat for these endangered marine animals. They screened the dolphin and porpoise blubber, muscle, liver, kidney and brain tissue samples for 62 individual LCMs.
Four compounds accounted for the majority of what was detected. Prior studies identified similar LCMs in the fish and invertebrates that these dolphins and porpoises eat, which the researchers say supports the idea that the pollutants enter through diet rather than directly from water.
Most of the LCMs found in dolphins and porpoises likely originated from television and computer screens, with smaller contributions from smartphones.
Although the contaminants were most concentrated in blubber, the researchers were surprised to discover small amounts in other organs, particularly the brain, revealing potential health hazards such as neurotoxic risks.
In additional lab tests, several common LCMs, including the major four in these samples, altered gene activity such as those related to DNA repair and cell division in cultured dolphin cells.
The researchers call for further investigation into the effects of LCM pollution on wildlife, highlighting the need for urgent regulatory action and improved e-waste disposal.
“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,” says Yuhe He, a researcher at City University of Hong Kong and a corresponding author of the study.
Data from the American Chemical Society