Plastic Spills Harm Sea Life, Posing Threats to the Food Web

Plastics and plastic chemicals are increasingly produced and traded across the world. With increasingly complex toxic cargos and frequently reported shipping accidents, a global concern has emerged around the impacts that plastics may have on marine environments. Now a new study demonstrates that these complex spills of plastics and chemicals that beached after a disastrous shipping accident in Sri Lanka may harm plankton - small organisms that make up the basis of the marine food web, create oxygen, and that help reduce atmospheric carbon. 

The X-Press Pearl disaster has had devastating impacts on our coastal areas, exacerbated by a lack of awareness about its effects on the food system and health," said Chalani Rubesinghe, a co-author of the study from the Sri Lankan group Centre for Environmental Justice (CEJ). "A healthy ocean environment is vital for our communities, but spills of plastics and plastic chemicals put both our oceans and essential seafood sources at risk."

In the study published today in Environmental Research, plastic debris was taken from coastal areas of Sri Lanka, the site of a major plastic spill in May 2021 following the explosion on the X-Press Pearl container ship, which released thousands of pounds of plastic pellets. Samples of burnt plastics were collected four months later and the researchers used the samples to simulate contaminated seawater. 

The study found that the burnt plastics leached a complex mixture of toxic chemicals, including flame retardants, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), pesticides, and others. Looking at how the leached chemicals might affect plankton living in the water, the study found that it:

• reduced the growth and development of sea urchin (meroplankton) larvae, with 94% of larvae showing malformations in the highest concentration solution;

• affected the reproduction of copepods (holoplankton), through decreased hatching success from 89% in the control to 29% in the highest concentration solution, and that it increased mortality of both larvae and adult zooplankton. 

• negatively affected the growth of phytoplankton.

“Plastics and chemicals are made from fossil fuels, making these types of incidents the oil spills of our time” said Therese Karlsson, IPEN Science Advisor and co-author of the study. “Our study shows the devastating impacts shipping spills can have and also highlights that plastics are not inert. They continuously sorb, leach, and transport toxic chemicals that can harm the environment.”

In the sea, plankton make up the base of the food web, providing food for larger animals, so any harm that comes to planktonic communities is likely to affect the overall balance of the ecosystem, including affecting the fish that people rely on for their dietary protein. It is striking to note that even several months after the accident, the collected debris adversely affected all tested species. 

“Given the quantity of plastics spilled and the wide spread of the debris, it seems likely that negative impacts from the X-Press Pearl accident continued for a long time,” said Sinja Rist, lead author of the study and a Researcher at the National Institute of Aquatic Resources (DTU Aqua) in Denmark.

On May 20, 2021, a fire erupted on the X-Press Pearl, a container ship anchored outside of Sri Lanka, leading to 13 days of burning and eventual loss of the entire cargo. The episode has been called the worst environmental disaster in Sri Lanka’s history. A 2022 study by CEJ and IPEN found that local fishermen reported a decrease in their catch following the disaster. 

The new study, “Impacts of spilled debris from the X-Press Pearl disaster in Sri Lanka on marine plankton” was conducted by researchers from CEJ, IPEN, DTU Aqua (at the Technical University of Denmark) in Copenhagen, Roskilde University, University of Las Palmas de Gran Canaria in Spain, and the Spanish Biomedical Research Center in Physiopathology of Obesity and Nutrition.