Legacy pollutants found in migratory terns in Great Lakes region

Date:
October 21, 2020
Source:
University at Buffalo
Summary:
Chemicals that haven't been manufactured in the U.S. for years
or even decades are still turning up in the bodies of migratory
terns in the Great Lakes region, a new study finds. The research
focused on three types of compounds: PBDEs, PCBs, and the breakdown
products, called metabolites, of DDT.



FULL STORY ========================================================================== Chemicals that haven't been manufactured in the U.S. for years or even
decades are still turning up in the bodies of migratory terns in the
Great Lakes region, a new study finds.


==========================================================================
The research focused on three types of compounds: polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and the breakdown
products, called metabolites, of dichlorodiphenyltrichloroethane (DDT).

Scientists discovered all three kinds of chemicals in the organs of over
two dozen common terns in breeding grounds along the Niagara River and
the shore of Lake Erie. The pollutants were found at various life stages,
in chicks, in juveniles and in adults.

Researchers also detected the compounds in emerald shiners, a small fish
that is the terns' primary food source in the area.

The research was published online on Sept. 3 in Environment International,
and will appear in the journal's November issue. Authors included
University at Buffalo chemists Diana Aga and Steven Travis, and SUNY
Buffalo State biologist Alicia Pe'rez-Fuentetaja.

Sales of PBDEs, a class of flame retardants used in car seats, carpet
padding, mattresses and many other household products, were phased out
in the U.S. in 2013. Production of PCBs, once widely used as a coolant
or insulating fluid in electrical transformers and capacitators,
ended in the country in 1979. And use of DDT, an insecticide, has
been prohibited in the U.S. for almost half a century, since 1972. The metabolite of DDT that the team found in the birds and fish is called dichlorodiphenyldichloroethylene (DDE).



========================================================================== "These chemicals are still there. They don't just go away. With PCBs,
for example, they haven't been produced in the U.S. for a long time
now, but you can still find them in the environment, in sediments and
in water. They don't degrade for many years. The fish eat organisms
that accumulate them, and then the birds eat the fish," says Aga, PhD,
Henry M. Woodburn Professor of Chemistry in the University at Buffalo
College of Arts and Sciences.

"The common tern is a threatened species in New York State, and their
numbers have not increased much despite state efforts to provide nesting
sites and surveillance. This study shows how wildlife is affected by
human pollution of aquatic systems and how the chemicals we produce can
have a multigenerational effect, being passed from mothers to chicks,"
says Pe'rez-Fuentetaja, PhD, Professor of Biology at SUNY Buffalo State
and Research Scientist at the Great Lakes Center at SUNY Buffalo State.

The levels of PCBs and PBDEs in the birds were high enough to potentially
harm the birds' health and affect population recovery, the authors write
in their paper.

Pollutants impact terns in every stage of life The findings illustrate
how household and industrial chemicals have become ubiquitous in the environment, where they can endure for many years, posing risks to
wildlife.



==========================================================================
In the case of terns, the threat begins from the earliest moments of
their lives, even before they hatch, says Travis, the paper's first
author, who successfully defended his PhD thesis at UB this fall.

He notes that the smallest chicks the team studied harbored higher concentrations of the chemicals than older birds and adults, indicating
that the compounds are being passed from parent to progeny. To test
this hypothesis, Travis has begun work on a study examining the levels
of pollutants in the eggs of common terns and other wild aquatic birds.

"We see these really high concentrations in the smaller chicks, which
indicates that there is maternal transfer of contaminants into the eggs,"
he says.

"These substances interfere with the reproductive system and are endocrine disruptors," Pe'rez-Fuentetaja says. "They tax the terns' livers as they
have to try and get rid of these pollutants, but the bioaccumulative
nature of PCBs, PBDEs and DDEs means that the birds will not be able
to fully detoxify themselves, and that they will pass part of their
body-load to the next generation. These substances can alter development
and neurological processes and could cause deformities, cancers and
impaired behavior." The research highlights the risks associated with
legacy contaminants, as well as the urgency of protecting the environment
as new issues surrounding other classes of persistent chemicals, such
as per- and polyfluoroalkyl substances (PFAS), emerge. Aga says that
once persistent pollutants become pervasive in water and soil, it's very difficult to get rid of them.

The new study shows how long-banned chemicals continue to jeopardize
the health of Great Lakes ecosystems.

"We can't say that all the chemicals we're seeing in the birds are coming
from the Great Lakes, as the birds migrate and could be accumulating
these compounds in other places along their migration route, too,"
Travis says. "But the specific types of PCBs and PBDEs we're seeing in the emerald shiners is similar to what we're seeing in the birds. This pattern
of chemical concentrations suggests that pollution in the Great Lakes
region is the source of at least some of this contamination." He adds, however, that, "One positive outcome of the study is that we only see
the metabolite of DDT, called 'DDE,' in the fish. This likely indicates
that there aren't new sources of DDT being introduced to Lake Erie and
the Niagara River, and that the DDT that was there is breaking down."

========================================================================== Story Source: Materials provided by University_at_Buffalo. Original
written by Charlotte Hsu.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Steven C. Travis, Alicia Pe'rez-Fuentetaja, Diana S. Aga. Evidence
of
continued exposure to legacy persistent organic pollutants
in threatened migratory common terns nesting in the Great
Lakes. Environment International, 2020; 144: 106065 DOI:
10.1016/j.envint.2020.106065 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201021111555.htm

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