Sludge Watch ==> Worms Tested for Contaminants in Sludge Ammended Soils - USGS

[Maureen Reilly]

www.usgs.gov/newsroom/article.asp?ID=1578


Wastewater Issues Get Wormy:  Recent research indicates that earthworms may 
be an important initial step by which organic contaminants could enter the 
terrestrial food web.



Wastewater treatment plants process millions of gallons of mixed solid and 
liquid human waste daily, returning treated effluent to surface and ground 
water and disposing of the residual sludge.  Roughly half of the many 
thousands of dry tons of treated sludge (usually referred to as biosolids) 
generated annually in the U.S. are applied to agricultural soils as a 
nutrient-rich soil amendment.

Recent USGS research has identified a wide variety of organic contaminants 
(such as disinfectants, pharmaceuticals, synthetic fragrances, and 
plasticizers) that can be present in biosolids, often in concentrations tens 
to thousands of times higher than found in treated liquid waste.  One 
concern related to the practice of land application of biosolids is whether 
any of these organic contaminants find their way into soil-dwelling 
organisms.

To address this concern, USGS and Eastern Washington University scientists 
collaborated on a study of earthworms collected from agricultural soils in 
the Midwest and Western United States that had been exposed to land-applied 
biosolids.


The samples were  analyzed for a diverse array of pharmaceuticals and other 
organic contaminants (77 target compounds were measured).  Soil and 
earthworm samples were collected from select agricultural fields early and 
late in the growing season.  Thirty-one compounds including triclosan 
(household disinfectant), several fragrances, caffeine, and fluoxetine (the 
antidepressant Prozac) were detected in earthworms from biosolid-applied 
fields, with tissue concentrations ranging from 100's to 1000's of 
micrograms per kilogram (parts per billion).

These results demonstrate that earthworms can accumulate a range of these 
chemically diverse organic contaminants within their tissues, and may be an 
important initial step by which these compounds could enter the terrestrial 
food web.

For more information contact Ed Furlong, USGS, at efurlong at usgs.gov or 
303-236-3941, and Chad Kinney, Eastern Washington University, at 
ckinney at mail.ewu.edu or 509-359-7932. SETAC presentation is on Thursday, 
Nov. 9, 4:10 p.m., Room 516 AB, Palais de Congrès.