Sewage sludge a threat?
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WASHINGTON, May 14, 2014 -- A U.S. Geological Survey (USGS) study shows the application of sewage sludge as fertilizer on farm fields can leave traces of prescription drugs and household chemicals long after the biosolid has been applied to the soil.
USGS scientists say the study could indicate that chemicals from antibacterial soaps, cleaners, cosmetics and prescription drugs like Prozac are found in greater concentrations deep in the soil and could find their way into groundwater sources.
After testing for several years on an eastern Colorado wheat field that uses treated sludge from a wastewater treatment plant, the research team cited 57 “emerging” contaminants that appear with growing regularity. They found 10 of the contaminants anywhere from seven to 50 inches down 18 months after the sludge was applied at points where the contaminants did not previously exist.
Some 7 million tons of treated sewage sludge is applied to farm fields each year. The effects of the trace amounts of the contaminants - measured in the soil in parts per billion - on human health and the environment are relatively unknown.
However, FDA has expressed concern that antibacterial compounds used in soaps, toothpastes and cosmetics could help cause antibiotic resistance and has called on manufacturers to demonstrate the safety and effectiveness of their products.
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