Eric Montie, the lead author on the study currently in press and published online April 17 in Environmental Pollution, performed the research as a student in the Woods Hole Oceanographic Institution-MIT Joint Graduate Program in Oceanography and Ocean Engineering and as a postdoctoral fellow at the Woods Hole Oceanographic Institution (WHOI).
The final data analysis and writing were conducted at College of Marine Science, University of South Florida, where Montie now works in David Mann’s marine sensory biology lab.
Co-author Chris Reddy, a senior scientist in the WHOI Marine Chemistry and Geochemistry Department, describes the work as “groundbreaking because Eric measures a variety of different chemicals in animal tissues that had not been previously explored. It gives us greater insight into how these chemicals may behave in marine mammals.”
Montie analyzed both the cerebrospinal fluid and the gray matter of the cerebellum in eleven cetaceans and one gray seal stranded near Cape Cod, Mass. His analyses include many of the chemicals that environmental watchdog groups call the dirty dozen, a collection of particularly ubiquitous pesticides that were banned in the 1970s because of their hazards to human health. But the Montie study goes much further in the scope of contaminants analyzed. And many of the contaminants are anything but benign.
The chemicals studied include pesticides like DDT, which has been shown to cause cancer and reproductive toxicity, and PCBs, which are neurotoxicants known to disrupt the thyroid hormone system. The study also quantifies concentrations of polybrominated diphenyl ethers or PBDEs (a particular class of flame retardants), which are neurotoxicants that impair the development of motor activity and cognition. This work is the first to quantify concentrations of PBDEs in the brains of marine mammals.
The results revealed that concentration of one contaminant was surprisingly high. According to Montie, “The biggest wakeup was that we found parts per million concentrations of hydroxylated PCBs in the cerebrospinal fluid of a gray seal. That is so worrisome for me. You rarely find parts per million levels of anything in the brain.”
The particular hydroxylated PCB found at these soaring concentrations, called 4-OH-CB107, has some serious side effects. In rats, it selectively binds to a carrier protein called transthyretin, which has been found to be abundant in cerebrospinal fluid in mammals. This protein plays a role in thyroid hormone transport throughout the brain, though its exact role is not known. Thyroid hormone plays a key role in the development of the brain, as well as sensory functions, in particular hearing in mammals. Compromised hearing would have significant impact for dolphins, because as Montie points out, “these animals rely on hearing as their primary sensory modality to communicate and to find and catch food.”
Just how these chemicals might impact marine mammal health is something Montie plans to pursue. This summer, Montie, Mann, and Dr. Mandy Cook (from Portland University) will partner with scientists from NOAA to test the hearing in dolphins living near a Superfund site in Georgia and compare it to dolphins from locations where ambient concentrations of pollutants are significantly lower. Montie is also working with Frances Gulland, director of the Marine Mammal Center in Sausalito, CA, to examine how California sea lions’s exposure to PCBs may increase their sensitivity to domoic acid, a naturally produced marine neurotoxin associated with “red tides.”
The work of Montie and his colleagues lays the groundwork for understanding how environmental contaminants influence the central nervous system of marine mammals. Montie sees this work as the forefront of a new field of research, something that might be called neuro-ecotoxicology. For years, most of the work in this area focused on how concentrations of marine pollutants affected the animal’s immune system or its hormone systems. The research by Montie, Reddy, Hahn, and their coauthors provides tools to ask deeper questions about how the ever-growing list of contaminants in the ocean affect the neurological development of marine mammals.
And what sort of results does Montie expect this new field of neuro-ecotoxicology to produce? “I think we don’t really know the brunt of what we are going to see in wildlife.”
This study was performed with funding form the WHOI Ocean Life Institute, WHOI Marine Policy Center, Walter A. and Hope Noyes Smith, and an EPA STAR fellowship. Supplemental funding was provided from the Natural Science and Engineering Research Council (NSERC) of Canada (to Robert Letcher), David Mann at the College of Marine Science, University of South Florida, and a NOAA Oceans and Human Health postdoctoral traineeship provided by Jonna Mazet (UC Davis Wildlife Health Center), Kathi Lefebvre (Northwest Fisheries Science Center), and Frances Gulland (The Marine Mammal Center).
Related Links:WHOI Ocean Life Institute
Media Relations Office | Newswise Science News
Further reports about: > DDT > Marine science > NOAA > Oceanographic Institution > PBDEs > PCB > Pacific Ocean > Science TV > WHOI > brominated flame retardants > cerebrospinal fluid > contaminants > environmental pollution > hazardous cocktail of pesticides > marine mammals > metabolites > neuro-ecotoxicology > pollutants
Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy