Sludge Watch ==> Following the contaminants from your bathroom to the birds

[Maureen Reilly]

Noisy spring, silent summer?
Following the path of contaminants from your bathroom to the birds
Posted by Fawn Pattison  14 Mar 2008

This is a story about sludge, worms, and songbirds, and it starts in your 
bathroom cabinet.


When we treat our wastewater to remove "biosolids" -- a polite term for our 
human waste -- all sorts of other things end up in the leftover sludge, 
including the drugs we take and the "personal care products" like lotion, 
shampoo, makeup, and cologne that we slather on our bodies, which have been 
absorbed through our skin and then excreted in our waste. The treated 
wastewater is usually discharged into the local river, and the sludge that's 
been removed from it frequently becomes fertilizer for agricultural 
production.

Researchers at the U.S. Geological Survey have found that the hungry 
earthworms who feed on this sludge in farm fields contain concentrated 
levels of our drugs and personal care products in their bodies. In fact, a 
USGS study published in February found that the compounds bioaccumulate in 
earthworms, meaning that the worms bear higher levels of these pollutants 
than the surrounding soil does. The USGS researchers note that worms could 
become monitoring species to help us determine the relative pollution levels 
in soil, but state that the pollution in these worms have "unknown effects" 
for wildlife (read the story in Science News).

"Unknown" maybe in that particular study, but researchers in the U.K. 
published a disturbing study about a week later that provides some insight 
into what happens to the polluted worms: Birds eat them.


This particular study examined European starlings in the wild, who like to 
forage in farm fields where fertilizer from sewage sludge has been applied, 
because the soil is rich in earthworms and other organisms who are busy 
feasting on the nutrients in the fertilizer. But they're also feasting on 
the contaminants in the fertilizer, and those contaminants have an impact on 
the foraging birds (story in The New York Times).

The contaminants in sewage sludge can contain hormone-mimicking compounds 
that act like estrogen in the birds' bodies. (Following the thread here? 
Those compounds are the drugs and personal care products that the USGS was 
examining in the earlier study.)

The U.K. researchers found that the contaminants boosted development in the 
part of the male birds' brains that control their songs, making them sing 
longer and more complex songs. The researchers also found that female 
starlings preferred the long, complex songs of the contaminated male 
starlings.

The bad news is ... they're contaminated. The same endocrine-disrupting 
compounds in the male starlings that made them attractive as mates make them 
unfit as fathers, because the compounds suppress the birds' immune systems 
and make them sick. While that might be good news for American birders who 
aren't fond of invasive starlings, it's rather bad news for birds everywhere 
who like to eat worms. While that fat earthworm might taste good and improve 
a male songbird's chances of attracting a pretty lady bird, it could 
actually be crippling his chances of producing a healthy brood of babies.

This might seem like just a scientific curiosity if the same kinds of 
effects hadn't also been noted in many other species, including fish, 
reptiles, and amphibians. Sort of makes you think twice about that nice body 
spray in your bathroom cabinet that's supposed to make you more attractive 
to a mate, doesn't it?


http://gristmill.grist.org/story/2008/3/13/103138/633/