Article should clarify how mercury taints eagles.
An article that puts bald eagles' modern problems in context with the birds' history falls short when trying to explain future needs.
A story that ran last month in the Daily Freeman newspaper highlights findings -- but not conclusions or future suggestions -- from a recent biodiversity research report that investigated the extent of mercury contamination in New York's bald eagles (Mercury rising: bald eagles in region face new threat).
While the report was covered in other newspapers, this article captured the essence of what the birds face in an area known as a ‘hot-spot’ for mercury accumulation. It rightly places the new research report within the context of the history of bald eagle conservation. Reporter Ny Patricia Doxsey adeptly describes people's changing perceptions of the birds -- from a nuisance killed to near extinction in the early 1900’s to a threatened and protected species in the later part of the century.
It's a good history lesson and one that should not be forgotten given current levels and exposures to today's environmental contaminants. Eagles are excellent barometers of environmental health because they are sensitive to a number of known contaminants, most notably the insecticide DDT. The birds became the poster child for the ‘ban DDT’ movement due to the drastic effects of egg-shell thinning and the death of developing birds.
Bald eagles are good model species for humans. Like people, the birds can live a long time and generally eat fish and other foods that can be highly contaminated.
The similarities mean people also face health dangers from mercury, especially if they eat enough mercury-leaden fish to effect their health. Yet this important angle is left to the end of the article.
To better understand mercury's health impacts in people and eagles, the link between mercury and methylmercury and where/how they are measured could have been expanded. What do ‘blood’ and feather mercury levels mean? Why measure both? A clearer description could be useful to highlight the fact that blood levels often reflect recent exposure (from the diet) whereas feathers can represent chronic, lifetime exposure to the metal.
A big missing piece in the story was that Ms. Doxsey did not highlight the major conclusions and suggestions from the original study. For example, the study encourages continued and expanded monitoring of mercury in the birds and in other organisms from the region.
The report also suggests investigating exposures to other contaminants, such as common flame retardants. Although now mostly banned, PBDEs accumulate to high levels in birds. Health effects are largely unknown but it is possible the chemicals could interact with other contaminants, such as mercury, compounding their detrimental effects.
