New sensor spots minute quantities of atmospheric mercury

Researchers have developed a new sensor to detect minute levels of mercury in the atmosphere in just 10 seconds. The new highly sensitive, laser-based instrument provides scientists with a method to more accurately measure global human exposure to mercury, the researchers noted.

"Our instrument has the potential to greatly enhance our understanding of the atmospheric cycling of mercury and increase understanding of the global impact of mercury on human health," said co-author of the new study Anthony Hynes from University of Miami. Mercury is considered by the World Health Organisation (WHO) as one of the top ten chemicals or groups of chemicals of major public health concern.

It may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes. The new device uses a measurement approach called sequential two-photon laser induced fluorescence (2P-LIF) and uses two different laser beams to excite mercury atoms and monitor blue shifted atomic fluorescence.

The researchers tested the new mobile instrument, alongside the standard instrumentation that is currently used to monitor atmospheric mercury concentrations. The 2P-LIF instrument measured ambient mercury at very minute levels within 10 seconds, whereas its counterpart instrument required at least 2.5 minutes.

Mercury is deposited on the ground (dry deposition) or via rainfall (wet deposition) where it bioaccumulates and biomagnifies, ending up at much high concentrations in fish and mammals. Direct exposure to mercury by humans is primarily through the ingestion of methyl mercury from fish consumption. (The study was published in the journal Atmospheric Measurement Techniques)