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A new study offers an explanation to the mystery of why pharmaceuticals and other chemicals are 

, far from developed land that would create contaminated runoff.

 
"These chemicals such as antibiotics, and anti-corrosives and endocrine active chemicals were being found in lakes where we might not expect them because there was no surrounding development," said Mark Ferrey, a Minnesota Pollution Control Agency scientist who, in search of an answer, collected snow, rain and air samples at three locations in the Twin Cities and had them tested for 126 chemicals.

Scientists shrink to the cell level

 
Ferrey found 17, including DEET, cocaine, antibiotics, an anti-corrosion chemical, an x-ray contrast chemical and the pain reliever naproxen.

 
Ferrey calls this study a proof of concept. He hopes to do a larger study with more samples in the future. But this research raises a lot of questions.
 

"Just the fact that we found a number of these in air and precipitation is significant," said Ferrey. "Because some of these, number one, haven't been detected in air and precipitation before and it does explain how we might be detecting these chemicals in remote surface water."
 

 have found chemicals in precipitation. For example, pesticides and flame retardant chemicals have been found in Arctic snow. But this study confirms for the first time rain and snow are transporting some of the pharmaceuticals and chemicals researchers have been finding in Minnesota lakes and rivers. 

 
These chemicals are also getting into water through wastewater treatment plants and septic systems. Ferrey says evaporation might lift them from water into the atmosphere. Another source might be bio-solid sludge from wastewater treatment plants that is spread on farm fields. Other studies have shown fine dust from that sludge can travel for miles on the wind.
 


The chemicals found in rain and snow are at very low levels, mostly parts per trillion.  

Water problems around Minnesota and the nation

"Just because they're at very low concentrations doesn't mean that it's just a curiosity," said Ferrey. "We should probably be concerned about the effects some of these chemicals are having."
 

"Even at these nanogram per liter, part per trillion level concentrations, these chemicals can have very observable effects on  fish and wildlife in our lakes and rivers," he said.
 

Scientists have found that very small amounts of some of the chemicals can affect fish reproduction or cause genetic changes. Ferrey says more work is needed to fully understand the long term effects.


 
The study is published in the journal 

Dan Gunderson

Author

A new study offers an explanation to why pharmaceuticals and other chemicals are found in remote Minnesota lakes. Research over the past decade has found drugs and chemicals like the insect repellent DEET are common in surface water.

Study: Rain and snow can transport chemicals to Minnesota's lakes, rivers

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