A new Queen’s University study shows that detergents used to clean up spills of diesel oil actually increase its toxicity to fish, making it more harmful. The detergents are oil dispersants that decrease the surface tension between oil and water, allowing floating oil to mix with water as tiny droplets. Dr. Peter Hodson and his team found that dispersion reduces the potential impacts of oil on surface-dwelling animals, While this should enhance biodegradation, it also creates a larger reservoir of oil in the water column.
This increases the transfer of hydrocarbons from oil to water, Dr. Hodson explains. The hydrocarbons pass easily from water into tissues and are deadly to fish in the early stages of life. “This could seriously impair the health of fish populations, resulting in long-term reductions in economic returns to fisheries,” he says.
The study is published in the journal, Environmental Toxicology and Chemistry.
The researchers also determined that even though chemical dispersants are not typically used in freshwater, turbulent rivers can disperse spilled diesel and create similar negative effects.
– source queensu