| |
Persistent Organic
Pollutants (POPs) in Alaska: What Does Science Tell Us
Produced
by Circumpolar Conservation Union
In Cooperation with Alaska Community Action on Toxics
October 2000
Executive
Summary
For
most people in the U.S., few places seem more remote than the Alaska,
conjuring up images of large expanses of pristine, isolated wilderness.
It is unlikely, however, that when most people in the U.S. think
about Alaska, they imagine a huge sink for toxic chemicals. These
chemicals, though not widely-used in the circumpolar regions, are
slowly and inexorably building up there in the fat and tissues of
creatures up to the highest levels of the food chain – including
men, women, and nursing infants.
Much of the evidence for the accumulation of persistent organic
pollutants – POPs - in the Arctic has come from countries other
than the U.S. While a substantial body of information has been developed
regarding the mechanisms and impacts of pollution in the Canadian
Arctic and in Europe, a similar depth of data has not existed about
the U.S. Arctic. The purpose of this report is to provide a brief
synthesis of what is known about POPs in Alaska. The focus is on
the food web which is the basis for the subsistence diet of many
Native Alaskan communities, and the human health impacts of the
contamination of that web. This includes an overview of the scope
of current and ongoing research on contaminants in Alaska and, based
on that, the identification of gaps in knowledge about POPs contamination
in Alaska.
It is critical to acknowledge that traditional knowledge is key
to understanding environmental changes in Alaska. Observations based
on traditional environmental knowledge have increasingly noted diseases
and abnormalities in species of fish and wildlife relied upon for
food by Native peoples. On-line reports of discussions in Native
villages in different areas of Alaska are used in this report to
supplement and enhance mainstream data sources, which cannot fully
encompass the scope and impact of contamination in tables and statistics
alone. Published reports identifying and describing the use and
significance of traditional foods are also critical in helping determine
pathways of exposure and the magnitude of effects of persistent
toxic contaminants.
An Overview of POPs
Persistent organic pollutants are a group of chemicals which are
defined by certain shared key characteristics. They are man-made
organic compounds and highly toxic. They persist in the environment,
and bioaccumulate in living organisms, often preferentially in the
lipid, or fatty, tissues. They are able to travel long distances
around the globe, due in part to their tendency to degrade very
slowly, and their ability to evaporate and recondense (called volatilization
and revolatilization, or global distillation) – sometimes in
repeated cycles – as they travel north. They migrate to northern
climates because of strong south to north air flows, which transport
contaminants from lower latitudes. Most POPs are industrial chemicals
or pesticides which were invented for specific uses, but some, such
as the dioxins and furans, are byproducts of industrial and incineration
activities in which chlorinated chemicals are significant constituents.
Twelve POPs have been identified as targets for early global action
in the POPs Treaty negotiations currently underway under the aegis
of the United Nations Environment Programme (UNEP): aldrin, dieldrin,
endrin, chlordane, DDT, heptachlor, mirex, toxaphene, hexachlorobenzene
(HCB), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins
(dioxin), and polychlorinated furans (furans). Also included in
this report is hexachlorocyclohexane (HCH), the gamma (_) isomer
of which is familiar to many people as the pesticide lindane used
for head lice. HCH, while not on the current UNEP POPs list, is
widely considered a significant Arctic contaminant.
Why Are POPs in Alaska of Concern?
•
Animals at the top of the food chain, high in the food web (e.g.,
trophic level), are the most exposed to many contaminants. Humans
are at the top of the food chain.
• Contaminants in the blubber and tissues of several Arctic
wildlife species, such as polar bears, seals, Arctic fox, and beluga
whales, have been found in levels equal to or higher than those
in experimental lab animals. Marine mammals are a critical part
of the subsistence diet in many northern communities. Contaminants
have also been found in fish, which comprise 60% of the traditional
foods relied upon by Alaska Natives and other Alaskans for subsistence.
• It is unknown whether or not levels of POPs will increase
or decrease in the environment in the future, but increases of some
chemicals are likely.
• Both infants and adults in initial human epidemiological
studies in Alaska have shown concentrations of some POPs contaminants
in their blood. Infants from the Yukon-Kuskokwim Delta have the
highest levels of DDT metabolites in their blood of any infants
in the circumpolar region.
Issues of Arctic contamination are of particular concern to Alaska
Natives and other indigenous Arctic peoples for two important reasons.
First is a widespread belief that existing, and especially recent,
information concerning environmental contaminants has not been widely
shared, leading to apprehension among Alaska Natives. Second is
the reality that this issue is not merely one of scientific curiosity
but is, in fact, of crucial importance because of the safety of
traditional foods. These foods are not only a significant part of
the diet of many Alaska Natives and a source of important nutrition,
but are also pivotal to the cultural and spiritual life of the people.
Why this report?
The intent, therefore, of this report is to bring together in one
place a synthesis and review of different repositories of information
about contaminants in Alaska to increase the overall understanding
of the current state of knowledge. In addition, there is a critical
need to develop a more comprehensive and accurate assessment of
the impacts of POPs contamination on public health. A solid foundation
of data is imperative to inform the public about the magnificent
resource represented by the U.S. Arctic and the dangers to it from
POPs contamination. A solid foundation of data is also imperative
if policy makers are going to make the best decisions and allocate
the resources required to accomplish the joint goals of public health
and environmental protection.
Everything begins with the food web
In reviewing what is known about POPs in Alaska, the effort has
been to build a picture of the food web upon which Alaska Natives
rely for their subsistence diet, often referred to as "traditional
foods". Information in this report is therefore divided into
three main areas, which mirror the path of the bioaccumulation of
contaminants up the food chain: contaminants in environmental media
(air, water, sediments, soil), contaminants in animals, also called
biota or wildlife, (fish, birds, invertebrates, terrestrial and
marine mammals), and contaminants in humans. This report also includes
tables showing the results of several studies which either included
Alaska-specific data or were investigations exclusively devoted
to Alaska.
Conclusions
This report demonstrates that there are virtually no areas of research
in the Alaskan arctic in which there are no gaps. In a sense, the
gaps define the landscape. Fish represent almost 60% of the subsistence
diet of most Alaska Natives, particularly salmon, yet there are
virtually no studies that have measured the contaminant levels in
salmon in the areas where they are most frequently harvested. Levels
of POPs contaminants have been found in other fish and shellfish,
however. Terrestrial animals contribute significantly to the diets
of many Alaska Natives living in the interior, yet there are no
studies which have looked in depth at the degree and scope of contamination
in these animals. Bald eagles and peregrine falcons have been studied,
however, and both have shown effects from pesticide levels in the
hatchability of eggs. Finally, although studies of marine mammals
including polar bears, whales, seals, and sea lions have been done,
all of which have showed contaminants in the blubber of these animals,
many questions remain unanswered with regard to trends and effects.
The most significant gap from a public health perspective is the
lack of information on to what extent the Alaska Native population
has been significantly exposed to POPs and whether health effects
have been seen as a result. Three small studies with humans are
cited in this report; one important source of ongoing research is
a project measuring the levels of contaminants in the blood in the
umbilical cords of women giving birth in rural Alaska.
Important gaps about environmental contamination also exist. There
is a lack of information about the behavior and fate of POPs and
other contaminants in the western Arctic ecosystem, extending from
Alaska to Russia. There is much to learn about to how to measure
these contaminants, information about long-range trends and inputs
into the Arctic, and long-range sources of dioxins and furans.
One of most significant barriers to the development of a coherent
body of knowledge regarding the U.S. Arctic has been the lack of
a well-organized, centrally coordinated effort to collect existing
information, facilitate the development and direction of needed
research, and leverage funding.
Recommendations and Priorities
1. The creation of a strong national Arctic contaminants research
and monitoring program in the U.S. Defining key species for
monitoring would be a useful first step in establishing such a program.
This would likely be based on potential for bioaccumulation, frequency
of use as a food source, and ecological importance. It is also crucial
that effective communication about contaminants be provided to citizens
and policy-makers in a long-term and comprehensive effort to protect
the public’s health. This initiative must include funding and
resources to assure continuity of projects and excellence in achievement.
2. Conduct a comprehensive survey and documentation of the main
contaminants found in Alaska and identification of their sources.
3. Investigate long-term and temporal trends in levels of POPs
contaminants, including loading and interactions between various
environmental compartments.
4. Establish a comprehensive health effects project to evaluate
and monitor human health in Alaska populations highly exposed to
POPs contaminants. What are the health effects of POPs contaminants
on humans who are most at risk? What are the reproductive, endocrine,
immune, developmental and other impacts on these populations? Is
there a relationship in humans between body burden levels of POPs
and the incidence of diseases? How do environmental exposures to
air, water, snow, and ice increase body burdens of POPs contaminants
in humans?
5. Develop detailed information about food consumption patterns
and contaminant intake levels by Alaskans who rely upon traditional
and wild foods for subsistence. Where do the greatest exposures
come from and how can they be decreased?
6. Investigate contaminant exposure patterns and pathways of
exposure in humans and wildlife in Alaska. What are the health
effects of POPs contaminants on the animal species most at risk?
What are the reproductive, endocrine, immune, developmental and
other impacts on these populations? How do environmental exposures
to air, water, snow, and ice increase body burdens of POPs contaminants
in different species, to what extent, and through what mechanisms?
7. Reduce and eliminate exposure to persistent chemicals through
rigorous, preventive measures at the international, national and
local levels. Such as achieving and ratifying a global, legally
binding POPs Treaty; ratifying the Aarhus (POPs) Protocol to the
ECE Convention on Long Range Transboundary Air Pollution; and creating
a national northern contaminants program, that educates and involves
citizens at the state and local level.
These steps should be grounded upon the implementation of the two
following basic principles:
The involvement and integration of Alaska Native people in the
design and implementation of a comprehensive contaminants research
program. This is critical if the full range of environmental,
cultural, and public health effects of POPs contamination are to
be understood and meaningfully addressed. The observations and theories
of indigenous peoples provide a unique and invaluable perspective
in the process of hypothesis generation, analysis of conditions,
and interpretation of results.
The application of the precautionary principle as the framework
for analyzing the outcomes of research initiatives and determining
the direction of policy decisions to be implemented. The precautionary
principle holds that where there is scientific evidence an activity
threatens wildlife, the environment or human health, protective
measures should be taken even in the absence of scientific certainty.
This shifts the burden of proof and requires a show of no harm as
a prerequisite for the production or continued use of any chemical
which has the potential for harmful health or environmental impacts.
We do not yet know whether people living in Alaska are being exposed
to enough of these chemicals to cause harmful health effects. Greater
attention and dedication of resources to the sources and implications
of such persistent pollutants could result in a greater ability
of Alaska and the U.S. to protect its interests and peoples.
|
