"These residues have been persisting since the late 1960s--that's what is really disturbing," said Dr. Andrew Iwaniuk, a post-doctoral research fellow in the U of A's Department of Psychology. "It has been years since it has been used and still has this effect."
The new research, published in Behavioural Brain Research, strongly suggests that exposure to environmental levels of DDT causes significant changes in the brains of songbirds.
Previous studies have suggested that exposure to DDT residues affect the brain, but none have actually demonstrated it. The research team, including Iwaniuk's supervisor, psychology professor and Tier II Canada Research Chair Douglas Wong-Wylie, used American Robins to test the idea. Birds are more susceptible to the effects of pesticide residues and other contaminants in the environment than other animals. As well, American robins are often exposed to high levels of DDT and other chemicals because they rely heavily on earthworms as part of their diet. They specifically chose these birds in the Okanagan Valley because at that location they are exposed to high levels of DDT, but relatively low levels of other chemicals.
The researchers captured 18 nestlings and then hand-reared and observed them for two years. They then sectioned the brains and examined the size of several brain regions. "We found that the regions sensitive to reproductive hormones--song production and courtship behaviour--were most affected by DDT," said Iwaniuk. "Song production is extremely important in attracting a mate or to mark out a territory.
"The issue is not that DDT is killing these robins but if they are growing up in this one area and then move to another, they won't be able to attract any females."
These effects were most prominent in the males, some of which experienced up to a 30 per cent reduction in brain region size compared to males at lower DDT exposure levels.
Whether this also applies to other animals and humans is unclear because there is not yet a strong understanding of how these chemicals in the environment affect the brain, but it is possible that humans exposed to similar levels of DDT will also be at risk of neurological damage.
"The take-home message is that people need to be more cognizant of their use of pesticides and herbicides," said Iwaniuk. "People need to be careful about using chemicals in their homes or farms. Who knows the effects these will have down the road."
Phoebe Dey | EurekAlert!
Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH
Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences