U.S. Geological Survey Home Page USGS Patuxent Wildlife Research Center Science Meetings; dedicated to Chandler S. Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Dedicated to Chan Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Poster Abstracts from USGS Patuxent Wildlife Research Science Meetings, October, 2006
Patuxent Science Meeting 2006 Poster Abstract

Restoration of the Lake Michigan ecosystem: a 33-year study of

declines in pollutants in Red-breasted Merganser eggs

Heinz GH, Stromborg KL (FWS), Faber R (St. Mary's College, MN)

The Great Lakes have suffered a long history of contamination by organochlorine pollutants.

These pollutants resulted in devastating declines in populations of fish-eating birds. Regulations

banning or strictly regulating certain pesticides and polychlorinated biphenyls (PCBs) began in

the early 1970s, but some of these contaminants were so persistent that it took decades before

bird numbers rebounded. As a means of documenting the gradual declines in these pollutants

that corresponded to the recoveries of fish-eating bird populations, we measured organochlorine

pollutant concentrations in eggs from red-breasted mergansers (Mergus serrator) in

northwestern Lake Michigan. We collected eggs three times, spaced 12 years apart (1977-78,

1990, and 2002). From 1977-78 to 1990, concentrations of most organochlorine contaminants

declined in the eggs of red-breasted mergansers, and further declines took place between 1990

and 2002. Between 1977-78 and 1990 total PCBs decreased 60% (from 21 ppm to 8.5 ppm,

wet-weight). An additional decline of 46% took place between 1990 and 2002 (8.5 ppm to 4.6

ppm). The total decline between 1977-78 and 2002 was 78%. Between 1977-78 and 1990 DDE

decreased 66% (from 6.5 to 2.2 ppm), and from 1990 to 2002 an additional decline of 36% took

place (from 2.2 to 1.4 ppm) yielding a total decline of 78%. Between 1977-78 and 1990 dieldrin

decreased only 16% (from 0.82 to 0.69 ppm); however, from 1990 to 2002 a 96% decrease

occurred (from 0.69 to 0.03 ppm) for a total decline of 96%. When the earliest data available

(Faber and Hickey 1973) were used as a baseline, the decline in total PCBs was 95% (84 to

4.6 ppm) and in DDE, 97% (44 to 1.4 ppm). The results of this earlier study, when combined

with those from our three egg collections, show an encouraging decline in organochlorine

contamination in Lake Michigan over the 33-year time frame, 1969 to 2002. Although other

problems unrelated to environmental contaminants still plague the Great Lakes, restoration of

many fish-eating bird populations can be traced to regulations controlling the release of

Friday, September 22, 2006



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