The finding, by a team of environmental engineers at the University of California, Berkeley, suggests these transformations could complicate efforts to reduce or eliminate the most problematic polybrominated diphenyl esters (PBDEs) from the environment.
"This study, for the first time, establishes that microbes found in every-day settings can degrade relatively stable forms of PBDEs, making them far less stable and potentially more toxic," says Lisa Alvarez-Cohen, Ph.D., the study’s corresponding author. "It implies that current and planned bans of the most toxic forms of PBDEs may be ineffectual if the less toxic forms are rendered more toxic when released into the environment."
In laboratory animals, high blood levels of PBDE are associated with cancer, lowered immunity, thyroid problems, and learning and memory difficulties. Although PBDE levels in people haven’t reached the levels of laboratory animals, Alvarez-Cohen says scientists are concerned because they are rising in humans at an exponential rate, doubling every two to five years.
In 2004, U.S. manufacturers reached a voluntary agreement with the EPA to stop making and selling penta-BDEs and octa-BDEs, two potent forms of PBDEs linked to health problems in animals. Deca-BDE, the most commonly used form of PBDE, remains on the market because it is considered more stable and less readily absorbed into the body, Alvarez-Cohen says. Laboratory studies, however, have shown that over time, both deca- and octa-BDEs can break down into potentially more harmful forms, including penta- and tetra-BDEs.
This new study supports the notion that this process also could occur in the real world, raising concerns about the continued manufacture and use of deca-BDEs, Alvarez-Cohen says. In their study, Alvarez-Cohen and her colleagues exposed octa-BDE and deca-BDE to five types of anaerobic bacteria commonly found in the soil. Based on previous research with other compounds, they anticipated that the bacteria would break down deca-BDEs into benign components. Instead, the microbes transformed deca-BDEs into octa-BDEs and the octa-BDEs into the more harmful penta- and tetra-BDEs.
"Now that we understand that certain PBDEs found in the environment can be transformed into more toxic forms, we need to make more intelligent policy decisions with respect to how, or even if, we should use these compounds," Alvarez-Cohen says.
PBDEs are used in televisions, computers, wire insulation, upholstery and many other products containing plastic and foam. If these products overheat, PBDEs release atoms called bromines that sap oxygen from the air, preventing a fire. Over time, PBDE’s can leach into the air, soil and sediment, and move up through the food chain. These compounds have been detected in fruits and vegetables, meats, dairy products and even household dust.
The American Chemical Society — the world’s largest scientific society — is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.
Michael Bernstein | EurekAlert!
Transport of molecular motors into cilia
28.03.2017 | Aarhus University
Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences