Toxic E-Waste Chemicals Found in Dolphins and Porpoises, Raising Ocean Health Concerns

Liquid crystal monomers (LCMs), essential components of television, computer, and smartphone screens, are accumulating in the tissues – including the brains – of endangered dolphins and porpoises, according to a new study published in Environmental Science & Technology. This discovery highlights a growing threat from electronic waste (e-waste) and its potential impact on marine ecosystems and, potentially, human health.

The Ubiquitous Spread of LCMs

LCMs control how light passes through display screens, producing the high-quality images consumers expect. Their widespread use means these chemicals are now pervasive in the environment, found in indoor air, dust, and wastewater, ultimately ending up in coastal areas. Previous research has indicated potential health risks associated with LCM exposure in both humans and aquatic species, but the extent of their impact on marine food chains and top predators remained largely unknown.

Study Reveals Accumulation in Marine Mammals

Researchers, led by Bo Liang and Yuhe He at City University of Hong Kong, analyzed tissue samples from Indo-Pacific humpback dolphins and finless porpoises collected in the South China Sea between 2007 and 2021. They screened for 62 individual LCMs in blubber, muscle, liver, kidney, and brain tissue. The analysis revealed that four compounds accounted for the majority of the detected LCMs.

Key Findings of the Research

• Accumulation in Multiple Organs: While LCMs were most concentrated in blubber, the researchers were surprised to find them present in other organs, particularly the brain.
• Neurotoxic Potential: The presence of LCMs in the brain raises concerns about potential neurotoxic effects on marine mammals.
• Dietary Exposure: Similar LCMs were previously identified in the fish and invertebrates consumed by these dolphins and porpoises, suggesting that dietary intake is a primary route of exposure.
• Changing LCM Levels: LCM levels in porpoise blubber fluctuated over the 14-year study period, generally increasing with the expansion of LCD display use and declining more recently with the shift towards LED displays.
• Gene Alteration: Lab tests showed that several common LCMs altered gene activity related to DNA repair and cell division in cultured dolphin cells, indicating potential negative impacts.

Implications for Ocean Health and Beyond

“Our research reveals that LCMs from everyday electronics are not just pollution — they’re accumulating in the brains of endangered dolphins and porpoises,” says Yuhe He. “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, ourselves.”

The study underscores the urgent need for improved e-waste disposal practices and regulatory action to mitigate the release of LCMs into the environment. With a record 62 million tonnes of e-waste produced in 2022 [4], addressing this growing environmental problem is crucial for safeguarding marine ecosystems and potentially preventing the entry of these contaminants into the human food chain.

Sources

American Chemical Society, Euronews, The Guardian, Oceanographic Magazine