with Dr. Jules Blais
M. Blais is a biogeochemist and ecotoxicologist who studies
sources and pathways of persistent pollutants such as organochlorine
pesticides, polychlorinated biphenyls (PCBs) and trace metals like
mercury in aquatic environments. Jules M. Blais, PhD Associate Professor
Department of Biology, University of Ottawa, 30 Marie Curie Road,
Rm. 271 Ottawa, Ont. K1N 6N5,Canada.
- How is the
Arctic unique with respect to the accumulation of contaminants?
The Arctic tends
to accumulate persistent semivolatile chemicals like organochlorine
pesticides and PCBs because these chemicals tend to evaporate in warm
environments, and they tend to condense and concentrate in cold environments,
making the Arctic a natural sink for these chemicals. Colder temperatures
may also enhance preservation of these chemicals. In addition, these
chemicals tend to concentrate in foodchains because they are taken
up efficiently from digestion and are only eliminated from the body
very slowly. As a result, high concentrations of these chemicals are
sometimes observed in marine mammals and seabirds that are near the
top of a long complex foodchain.
any other factors beside seabird influence which may be contributing
to the contaminant level of these high Arctic ponds?
likely to be the dominant sources of persistent bioaccumulative
toxicants (like methyl mercury, organochlorine compounds, etc.)
in these ponds. Concentrations of these chemicals in sediments near
the cliffs where the seabirds are nesting are 10 to 70 times higher
than in sediments from ponds unaffected by seabirds. Independent
tracers of seabird influence (nitrogen, phosphorus, cadmium, dissolved
organic carbon) corroborate our conclusion that the contaminants
in these ponds are derived from seabirds. However, for the contaminants
to have entered the seabirds, they would have had to be transported
by air and ocean currents to the locations where the seabirds derive
the bulk of their nutrition. We know that these seabirds derive
their nutrition mainly in Jones Sound and Baffin Bay.
some limitations of this study?
are several things we still don't know about contaminant transfer
to the coastal Arctic. We have only studied this phenomenon in one
location so far in the Canadian Arctic, though there are indications
that similar responses are occurring in the Norwegian Arctic (at
Bear Island, for example). We also don't know the extent to which
these chemicals will accumulate in the aquatic and terrestrial foodchains.
How is human
health affected by the high level of contaminants in these remote
areas? (How are they exposed? What are the implications of exposure?)
are not sure of the role of contaminant biotransport by seabirds
as vectors for human exposure. There has been extensive research
done on human exposure to chemicals in the Arctic, with indications
that humans may be adversely affected by these chemicals. For example,
persistent organic pollutants like PCBs and methyl mercury are thought
to affect neural development and the immune system. As a result,
their abundance in certain northern traditional foods may lead to
IQ deficits and higher incidences of infections.
understanding of the mechanism of pollution transport in the Arctic
have any implications for developing strategies to protect humans
from these chemicals?
believe so. For example, arctic research on contaminants has already
been instrumental in developing legislation to restrict and ban
the worst of these chemicals, such as the Stockholm Convention on
Persistent Organic Pollutants, a legally binding international treaty
overseen by the United Nations Environment Programme.
the biggest challenge in conducting this study?
biggest challenge was the logistics of doing research in such a
remote setting. Arctic research requires a great deal of planning