Delaware Public Media

Less pollution in Delaware Estuary makes for healthier osprey

Jul 13, 2018

Studies from the United States Geological Survey show a decrease of pollutants in the Delaware Estuary is good news for the First State’s osprey population.

The final analysis of a 2015 USGS study shows osprey nested along coastal Delaware have fewer contaminants in their eggs compared with similar studies from the 1970s and early 2000s. The osprey population is also healthier.

The research is published by the U.S. Geological Survey in the journal, Science of the Total Environment.

Scientists tested eggs for legacy contaminants like organochlorine pesticides, as well as other chemicals used as flame retardants called polybrominated diphenyl ethers. These chemicals are known for thinning bird eggshells.

USGS Research Scientist Barnett Rattner led the tests.

“What we found is that many contaminants are still being detected, but for the most part many of the concentrations are lower than what we found in 2002 and what had been detected previously in others in the 1980s for example,” said Rattner.

The study found no evidence of eggshell thinning, and Rattner says hatchling development has also improved since 2002.

He points to recent cleanup efforts and pollution regulations as playing a significant part in restoring health to the First State ospreys.

“There are still some problems though with some compounds that are referred to sometimes as legacy contaminates that have very long half-lives. It has taken and will take longer for them to disappear if, in fact, they do disappear altogether,” he said.

Barnett says areas near the Delaware River did not show as much improvement as coastal Delaware and other areas in the estuary.

He adds the osprey is a good sentinel to measure environmental pollution.