Arsenic is a common element on Earth and is present in natural waters. Arsenic can enter drinking water supplies from natural deposits in rock or from commercial activities.  Arsenic in well-water poses a risk to many rural communities High arsenic levels can impair learning development and lead to an increased risk of cancer even below the 10 μg/L MCL set forth by the US EPA.  Accurate measurement of arsenic in drinking water at levels relevant to health requires expensive laboratory analysis. Low cost, portable test kits are available that can detect arsenic at higher levels, but are typically unreliable at the concentrations that cause human health concerns.  Most kits have a limited working range and many of them use highly toxic mercury bromide.  Decentralized sensors that could be used to monitor water from domestic wells or other drinking water sources at the household level would be a powerful tool for verifying that a drinking water supply is free from the concern of arsenic or other ultratrace contaminants. In addition, networks of decentralized sensors could help identify problems with aging and failing infrastructures such as contaminant intrusion through leaking pipes.  Thus, a rapid, cheap, sensitive and reliable method to detect arsenic in water is needed. The method should be free from using toxic chemicals and should be operated with little training.  Electrochemical biosensors, which use an enzyme, antibody or DNA as the detection element, are of interest for environmental monitoring due to their small size and portability. Arsenic is known to inhibit a number of enzymes including acid phosphatase, pyruvate dehydrogenase and acetylcholinesterase.  We have developed an inhibition based amperometric biosensor for arsenic using the enzyme acetylcholinesterase.  We will present the results of characterizing enzyme inhibition and immobilization on a screen printed electrode. The sensitivity of the biosensor to different forms of arsenic and other potential interferents will also be presented.

Developing a sensitive biosensor for monitoring arsenic in drinking water supplies

254th National Meeting (2017)

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