Levels of mercury in an endangered Pacific seabird species have increased substantially in recent decades largely due to industrial emissions from Asia, Harvard University researchers have found.
The novel study examined breast feathers from 54 black-footed albatrosses collected at U.S. natural history museums from 1880 to 2002.
The results, published online Monday in the Proceedings of the National Academy of Sciences, show an alarming rise in methylmercury, a neurotoxin that accumulates in the birds’ bodies from a diet of fish.
There are implications for human health, too. Consumption of mercury-tainted fish from the Pacific is an important source of human exposure to methylmercury in the United States and could harm neurodevelopment in children, warned study co-author Michael Bank, an environmental research associate at the Harvard School of Public Health.
"Methylmercury has no benefit to animal life and we are starting to find high levels in endangered and sensitive species across marine, freshwater and terrestrial ecosystems," Bank said in a statement. "Mercury pollution and its subsequent chemical reactions in the environment may be important factors in species population declines."
Lead author Anh-Thu Vo, who did her research while an undergraduate at Harvard, warned that mercury poisoning could undermine the reproductive capabilities of albatross and other long-lived seabirds.
"The Pacific in particular warrants high conservation concern, as more threatened seabird species inhabit this region than any other ocean," said Vo, now a graduate student at UC-Berkeley.
The researchers collected feathers from albatross specimens in the Harvard Museum of Comparative Zoology and the University of Washington Burke Museum of Natural History and Culture and analyzed methylmercury in samples over a 122-year period.
They found increasing levels of the toxin generally consistent with human-generated mercury emissions.
The research paper notes that mercury emissions have declined over the last two decades on every continent except Asia, where they nearly doubled from 1990 to 2005. Asia now produces two-thirds of the world’s airborne mercury pollution, with half of that coming from China.