Impact of pollutants on marine mammals

Extensive research on marine pollutants in marine mammals shows that these animals are exposed to toxic insecticidal compounds such as DDTs and PCBs, as well as new pollutants that appear as if they were BFRs (brominated flame retardants).

Eric Montie, the lead author of the study, was published in the April 17 Environmental Pollution magazine, conducting research as a graduate student in MIT's Oceanography and Marine Engineering High School Program. and Woods Hole Oceanographic Institute (WHOI). The final analysis data was made at the Marine Science School, University of Southern Florida, where Montie worked in David Mann's marine biology lab.

Co-author Chris Reddy, a scientist in the Department of Chemistry and Biochemistry at WHOI, described the study as "a breakthrough and Eris measured many chemicals in animal tissue that had not been previously detected." This study provides a deeper understanding of how these chemicals work within mammal marine animals. '

The study is a collaborative effort between Reddy's and Mark Hahn's labs at the WHOI Biology Department, where Montie is a postdoctoral researcher and researcher, as well as Robert Letcher at the Canadian Environment. Montie went to Environment Canada in Ottawa to learn the techniques needed to extract and quantify more than 170 different pollutants and their metabolism. He brought the methods of learning about WHOI and performed analysis in Reddy's lab. Reddy describes particularly complex methods and explains: 'It is not like making cookies Toll House. The fact that Eric made those methods fluently was amazing. '

Montize analyzed both cerebrospinal fluid and gray matter of the cerebellum in 11 mammalian marine species and a seal stuck in Cape Cod, Mass. His analysis includes many chemicals that environmental control groups called 'dirty dozen' , a collection of common pesticides that have been banned since the 1970s because of toxic to human health. . However, Montie's research is much broader within the range of contaminants analyzed.

The chemicals in the study include pesticides like DDT, known for their ability to cause cancer and infertility, and PCBs, neurotoxicants that destroy the thyroid hormone system. The study also quantifies the concentration of polybrominated diphenyl or PBDEs, a neurotoxin that weakens the development of motor and cognitive nerves. This is the first study to quantify the concentration of PBDEs in mammalian marine brains.

Atlantic dolphins and children. (Photo: Eric Montie)

The results show that the concentration of pollutants is surprisingly high. According to Montie, 'The most astonishing thing is that we found parts per million concentrations of PCBs in the spinal fluid of a gray seal. This is a really worrying news. You rarely find parts per million concentrations in anything in the brain. '

PCB hydroxylate found in parts per million, called 4-OH-CB107, has some serious side effects. In mice, this chemical binds to proteins called transthyretin, which is abundant in cerebrospinal fluid in mammals. This protein plays an important role in transporting thyroid hormones in the brain, but its exact role has not been clearly defined. Thyroid hormones play an important role in the development of the brain, as well as sensory abilities, especially the ability of mammalian hearing. Vulnerable hearing has a big impact on dolphins, Montie points out that 'this animal is based on hearing ability as the main way of perceiving communication as well as finding food'.

The effect of these chemicals on the health of marine mammals is what Montie tries to understand. This summer, Montie, Mann and Dr. Mandy Cook (from Portland University) will work with NOAA scientists to test the hearing ability of dolphins near the Superfund site in Georgia and compare with dolphins. in less polluted areas. Montie is also working with Frances Gulland, curator of the Center for Mammal Marine Animals in Sausalito, CA, to test how exposure of California sea lions to PCBs can increase their sensitivity to acids. domoic, a natural neurotoxin.

Montie's research and colleagues are fundamental to understanding the impact of environmental pollutants on the central nervous system of marine mammals. Montie argues that this is a pioneering study of a new field of research, possibly called neurotoxic ecology. For many years, most research in this area focused on the effects of the concentration of marine pollutants on the animal's immune system or hormone system. Research by Montie, Reddy, Hahn and other co-authors provides tools to ask deeper questions about the effects of pollutants, increasingly, on the neurodevelopment of dynamics. Marine mammals.

And what is Montie's prediction about the results of this new field of research? 'I think we do not really understand the burden that wildlife is suffering'.

The study was funded by the WHOI Marine Life Academy, WHOI Marine Policy Center, Walter A. and Hope Noyes Smith, and EPA STAR funds. In addition, the study also received funding from Canada's Natural Science Research Council (NSERC) and NOAA ocean and human health postdoctoral training program, by Jonna Mazet (Life Health Center). UC Davis wild life), Kathi Lefebvre (Northwest Marine Science Center), and Frances Gullan (Center for Marine Mammals).

Refer:
Eric W. Montie, Christopher M. Reddy, Wouter A. Gebbink, Katie E. Touhey, Mark E. Hahn, Robert J. Letcher.Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter printed short-beaked common dolphins and Atlantic white dolphins from the Western North Atlantic.Environmental Pollution, 2009;DOI: 10.1016 / j.envpol.2009.03.024