Measuring pollutants in marine environments

Citation

(1998), "Measuring pollutants in marine environments", Sensor Review, Vol. 18 No. 2. https://doi.org/10.1108/sr.1998.08718baf.005

Measuring pollutants in marine environments

Measuring pollutants in marine environments

Keywords Marine environment, Pollution, Sensors, University of Delaware

A University of Delaware chemistry and biochemistry professor and his colleagues have developed a micro-electrode that can be inserted into marine waters and sediments to measure simultaneously a number of metals and chemicals to levels as low as 1ppb. Traditionally, sensors could characterise only gaseous compounds and typically only one gas could be measured per electrode. In addition, most existing microelectrodes do not stand up well in the often muddy conditions of marine environments.

George W. Luther's sensor consists of a gold wire plated with mercury and enclosed in a glass tube into the centre of a very thin-walled glass tube just 200 microns in diameter and about 4cm long.

The mercury in the wire reacts with chemicals in marine water or sediment, creating a current directly proportional to the chemicals' concentration. The device can simultaneously measure dissolved oxygen, manganeses, and iron, as well as pH levels, in seawater.

Luther field-tested his micro-electrode in Hawaii's Kaneohe Bay: "It's very much like a Delaware salt marsh", he said, "in that it cycles iron very rapidly".

Future plans call for testing the sensor in Hawaiian volcanoes and hydrothermal vents, which are filled with gases, such as hydrogen, sulphide and methane, as well as iron and other metals.