Tracking water contamination

Tracking water contamination

August 17, 2016

  • A new environmental monitoring device has been pioneered by Rolf Halden's Center for Environmental Security. 


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August 17, 2016

A new environmental monitoring device has been pioneered by Rolf Halden's Center for Environmental Security. Rolf Halden's innovative in situ sampler was recentlly featured in Environmental Monitor, a trade magazine for environmental professionals. 

Here's the article below: 

"For common water quality parameters like pH or dissolved oxygen, there are plenty of devices out there to measure them. For low-level contaminants like pesticides, however, the situation is a little trickier. A tried-and-true method of acquiring chemical contaminant data has traditionally involved collecting “grab samples” by dipping bottles into the target water source and then transporting those bottles, which are often very heavy when they are full of water, to a lab for analysis. The trouble with this method is that the sample is from a single point in time and may not represent fluctuations in the contaminant that occur over weeks or months. Additionally, collecting water and shipping it to a lab for analysis can be expensive and something of a hassle.

Researchers at Arizona State University have tried their hand at addressing this issue. They have developed a sampling device that integrates some of the same equipment used in the lab to enhance the signal of low-level chemical compounds; it is a device capable of collecting the chemicals directly from water, without collecting the water itself.

One of the key features of the device, aside from its ability to capture chemicals from water, is its unique ability to sample contaminants in bulk water and the sediment pore water (e.g., in a lake) simultaneously. The device was recently used in waterways of the U.S. Southwest to assess the occurrence of the pesticide fipronil, which may play a role in the plight of honeybee populations in the United States.

The device is called the In Situ Sampler for Biphasic water assessment (IS2B), and uses solid phase extraction (SPE) technology in its design to concentrate the analytes directly in the stream of interest. SPE involves passing water through a cartridge filled with a selected resin matched to the chemicals of interest. The resin adsorbs the chemicals, effectively precipitating them out of the dissolved phase. The cartridge is subsequently taken back to the lab, the contaminant extracted from the resin using standard analytical methods, and then analyzed. The initial investigation of the device’s utility, led by Dr. Samuel Supowit while a graduate student at Arizona State, showed that the approach produces reliable results.

“We’ve taken that technology and put it into a sampler so that it is done in the field. That technology is very common and as a mature technology, cartridges and resins can be purchased commercially,” said Erin Driver, a graduate research associate at Arizona State University’s Biodesign Institute.

 

Written by: Joe Caspermeyer