A new U.S. Geological Study report suggests that chemicals found in nonstick cookware and water repellents could be affecting tree swallows (Tachycineta bicolor) living along the upper Mississippi River. It's been known that the Mississippi River around and south of the Twin Cities is contaminated with perfluoroalkoxy (PFA), a chemical found in many household products. The report says wastewater discharges and contaminated groundwater from manufacturer 3M's facilities have created hotspots for PFAs, even though it's been more than a decade since the company stopped producing them. USGS researchers studying tree swallows in Wisconsin and Minnesota found that birds with high concentrations of PFAs are less likely to hatch.
USGS Wildlife Biologist Chris Custer says the probability of problems increases with contamination: “I like to use George Burns [as an example]: he smoked cigars and cigarettes until he was 100 and never got lung cancer. Another person smoking the same amount might die in their thirties. It's the same thing with bird eggs. You can have the same amount of contamination and in some, it will cause a poor hatching and another with a different genetic makeup might hatch fine.”
Custer says the chemicals are found in everything, but the exposure is usually so minimal that it does not cause any harm. She says tree swallows may be ultra-sensitive to PFAs.
The study does recognize that other factors may also be causing the declines in tree swallow populations.
Source: Wisconsin Public Radio News, 1 November 2103
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