ducks point to lake toxin
While focused on levels of selenium in the lesser and greater
scaup, the findings also raise wider concerns.
"(Selenium poisoning) could be affecting quite a number
of species ... including some fish species," said Scott
Petrie, research director for the Long Point Waterfowl and
Wetlands Research Fund. Selenium, an essential trace nutrient,
is released to water from both natural and industrial sources.
It can be highly toxic, crippling reproductive ability.
"It's quite alarming that you've got this semi-metallic
trace element showing up in such high levels in certain
bird species," said Petrie.
Scaup populations across the continent have dropped by as
much as 50 per cent since the mid-1980s, and suspicion has
now fallen on the entry of zebra mussels into their diet,
likely imported into the Great Lakes in 1986 via a foreign
ship, dumping water ballast.
Because they are "filter" feeders, the mussels ingest and
retain toxins in the water, such as PCBs, which are then
passed on to waterfowl. Petrie said further research is
needed to confirm mussels are contaminated with selenium,
and in turn poisoning scaup.
A drastic decline in the North American population of
a duck species could be due to a chemical contaminant
in the Great Lakes the birds are ingesting in unexpectedly
high amounts, new research suggests.