Researchers have figured out what makes certain chemicals accumulate to toxic levels in aquatic food webs. And, scientists have developed a screening technique to determine which chemicals pose the greatest risk to the environment.
According to the study led by the U.S. Geological Survey, two traits were identified that indicate how chemicals can build up and reach toxic levels: how easily a chemical is broken down or metabolized by an organism and the chemical's ability to dissolve in water.
This model provides a new global tool for screening existing and new organic chemicals for their biomagnification potential. Hot colors (red, orange and yellow) indicate a high probability of biomagnification and cool colors (greens, blues) indicate a low probability of biomagnification.
These traits account for how most chemicals concentrate, or biomagnify, in ever-higher levels as one goes up the food chain from its base to its top predators, such as fish, people, or polar bears. Chemicals that have the ability to biomagnify, such as DDT, can have adverse effects on human and wildlife health and the environment.
"Chemical manufacturers and regulators can use this information to reduce the risks of harmful chemical exposures to ecosystems and the fish, wildlife and people who live in them," said David Walters, a USGS research ecologist and lead author of the study. "By screening for these two characteristics, we can identify chemicals that pose the greatest risk of the thousands that are on the market and for new ones being developed."
The study found that poorly metabolized compounds tend to remain in animal tissues and are passed up the food chain in higher, more toxic amounts as one animal is eaten by another and so on. Likewise, compounds that don't dissolve well in water accumulate in animal fats, ultimately exponentially increasing in top predators.
Beyond these chemical properties, the researchers found that certain ecosystems and food webs are more vulnerable to biomagnification than others. For example, extremely high biomagnification occurred in ocean food webs that include birds and mammals. The authors noted this may be in part due to longer food chains in these ecosystems that is, many levels and kinds of predators - and because warm-blooded animals need to consume more food than do cold-blooded animals like fish.
Building upon these results, the researchers developed a model of biomagnification based upon how chemicals metabolize and dissolve in water. The likelihood that a chemical would biomagnify was highest - nearly 100 percent -- for slowly metabolized compounds such as chlorinated flame retardants and PCBs, or polychlorinated biphenyls, regardless of their solubility in water.
We need to learn from our previous mistakes and have more informed and responsible design and use of chemicals in the environment," said Karen Kidd, a Canada Research Chair at University of New Brunswick Saint John and co-author of the study. "Our global review provides a straightforward approach for reducing the use of chemicals with the properties to concentrate through food webs. This is a critical step for decreasing risks for humans and wildlife from potentially harmful chemical exposures in foods."
Since the emergence of DDT as a global problem for wildlife in the 1950s and 60s, science has kept a close watch on the behavior of persistent organic pollutants, especially chemicals that may concentrate through food webs to potentially toxic levels in wildlife and humans. Many are resistant to environmental degradation and remain in the environment for decades. While biomagnification can be measured in the laboratory, said Walters, it is best determined by measuring how much the chemical increases with each step in the food chain in wild animal populations.
USGS research partners in this study, "Trophic Magnification of Organic Chemicals: A Global Synthesis," include the Toxicology Centre at the University of Saskatchewan, the Canadian Rivers Institute at the University of New Brunswick, and Environment and Climate Change Canada. The study is published in Environmental Science and Technology.
This research was supported by the USGS Ecosystems and Environmental Health Mission Areas, the U.S. Environmental Protection Agency's Great Lakes Research Initiative, and the Canada Research Chair and Natural Sciences and Engineering Research Council (NSERC) of Canada programs.
USGS provides science for a changing world. Visit USGS.gov, and follow us on Twitter @USGS and our other social media channels. Subscribe to our news releases via e-mail, RSS or Twitter.
Links and contacts within this release are valid at the time of publication.
Catherine Puckett | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
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...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy