Large beached whale carcass on seaweed-covered shore with three people nearby

New Study Reveals Plastic-Related Chemicals in Southern Right Whales

  • by Eunah Preston

A new study has uncovered the first evidence of plastic-related chemicals accumulating in southern right whales and the first documented case of these contaminants being found in whale calves anywhere in the world.

Led by IBIOMAR researcher Dr. Luciano Gallo and Dr. Marcela Uhart, director of the UC Davis One Health Institute's Latin America Program, this research examined blubber samples collected from southern right whales that stranded at Península Valdés, Argentina. This sampling work was conducted as part of the Southern Right Whale Health Monitoring Program, a long-term effort that has investigated whale deaths and collected biological samples for more than 20 years.

Four people in waders carry gear toward a large beached whale on a rocky beach.
The Southern Right Whale Health Monitoring Program has been monitoring whale health at Península Valdés, Argentina, for over 20 years. This long term effort has resulted in one of the biggest datasets and sample banks for large whales worldwide, providing rare opportunities for health research and detection of changes over time. Photo credit: SRWHMP

Researchers looked for phthalates, chemicals commonly added to plastics to increase their flexibility. They detected at least one of the three phthalates analyzed in more than 90% of the whales sampled, including every calf in the study. One calf tested positive for all three compounds. These findings suggest exposure may begin before birth or during nursing through transfer from mother to calf.

Aerial view of a dark whale surfacing in clear turquoise water.
A southern right whale and her calf at the Península Valdés nursery ground, in Argentina. Until the calf is big enough to migrate to the feeding grounds, mothers nurse their calves while fasting, drawing energy from their blubber reserves. The fat-rich milk can be a conduit for toxic chemicals accumulated in the blubber. Photo credit: Nicolas Lewin

While phthalates have been linked to impacts on metabolism, development, reproduction, immunity, and hormone function in other marine species, their effects on whales remain unknown. The findings highlight an important area for future research as scientists work to better understand how plastic pollution may affect marine mammals.

The study also underscores the value of long-term wildlife health monitoring. Without decades of consistent fieldwork and sample collection, emerging threats like chemical exposure from plastics could remain undetected.

As sentinels of ocean health, southern right whales can help scientists identify environmental changes that affect entire ecosystems. The findings serve as another reminder that addressing plastic pollution means looking beyond visible debris to the chemicals plastics release throughout their lifecycle and continuing efforts to reduce plastic waste at its source.