Mar. 17, 2009 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 may be the best way to treat spills in the long term
because the dispersed oil is diluted and degraded," says Biology
professor Peter Hodson. "But in the short term, they increase
the bioavailability and toxicity of the fuel to rainbow trout by
100-fold." 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. 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 impai