生物多樣性研究中心（Center for Biological Diversity）辯稱，美國本土經環保署核准使用的農藥，透過大氣、海洋、生物等途徑流竄到北極已是不爭的事實。
A conservation group says that in 60 days it will sue the U.S. Environmental Protection Agency for failing to consider impacts of contamination resulting from pesticide use in the United States on the threatened polar bear and its Arctic habitat.
The Center for Biological Diversity argues that pesticides approved by the EPA for use in the United States are known to be transported to the Arctic via various atmospheric, oceanic, and biotic pathways.
These pesticides are "biomagnified with each step higher in the food web, reaching some of their greatest concentrations in polar bears, the apex predators of the Arctic," the group contends.
Pesticides and related contaminants have been linked to suppressed immune function, endocrine disruption, shrinkage of reproductive organs, hermaphroditism, and increased cub mortality in polar bears.
The polar bear was formally listed as a threatened species under the Endangered Species Act on May 15, 2008 following a petition and litigation by the Center for Biological Diversity, but the EPA has yet to examine the impacts of any pesticide on the species.
All pesticides in the United States must be registered by the EPA before they can be lawfully used. Courts have held that the agency must examine the impacts of any pesticide it approves on species protected under the Endangered Species Act.
Meeting last week in Copenhagen for the first time in four years, the IUCN Polar Bear Specialist Group concluded that the adverse health impacts from contaminants and climate change are the two most serious threats to polar bear survival.
The Polar Bear Specialist Group renewed the conclusion from previous meetings that the greatest challenge to conservation of polar bears is ecological change in the Arctic resulting from climatic warming.
The Polar Bear Specialist Group noted that "polar bears suffer health effects from persistent pollutants."
At the same time, the Specialist Group concluded, "climate change appears to be altering the pathways by which such pollutants enter ecosystems."
The specialists reevaluated the status of the 19 recognized subpopulations of polar bears distributed over vast and relatively inaccessible areas of the Arctic.
They concluded that one of the 19 subpopulations is currently increasing, three are stable and eight are declining. For the remaining seven subpopulations available data were insufficient to provide an assessment of current trends.
The worldwide total number of polar bears is still thought to be between 20,000 and 25,000. However, the scientists said that the "mixed quality of information on the different subpopulations means there is much room for error in establishing that range."