EurOCEAN 2000 - Vlaams Instituut voor de Zee

DEVELOPMENT AND TEST OF AN INNOVATIVE ION SELECTIVE
ELECTRODE MONITORING AND CONTROL SYSTEM FOR TOTAL
NITROGEN IN MARINE WATERS
702
John Barron 1 , Klaus Schmidt 2
1 Reagecon, Shannon free zone, Shannon, Co. Clare, Ireland; 2 Institut fur Unwelttechnologie
und Umweltanalytik e.V, Bliersheimer Straße 60, 47229 Duisburg, D.E.
1.1.1.1.1.1 INTRODUCTION
Coastal Zone pollution and Eutrophication of marine waters have been identified as key
environmental issues and problems affecting the seas around Europe (1) . The major
contributing element to these problems is Inorganic Nitrogen, the levels of which are rising at
an alarming rate.
Current farming practice in many countries, including excessive use of
Nitrogen containing artificial fertilisers, seepage of animal waste into water
ways, inadequate treatment of human sewage and several industrial processes
are major contributing factors. This excess of inorganic Nitrogen usually
occurs as Nitrate which is a nutrient leading to Eutrophication (1) .
Eutrophication can lead to algae blooms, proliferation of seaweed and many other adverse
effects on marine life depending on levels of pH, dissolved oxygen, salinity and temperature.
Nitrate may convert to other toxic forms of Nitrogen including Ammonia, Ammonium, or
Nitrite. These substances may also be produced by uneaten food in farmed fish, excreta,
chemicals/therapeutics and dead fish. All of these Nitrogen species combine to exhibit
varying degrees of toxicity on farmed fish including poor reproduction, stress, and chronic
illness (Ammonia), acute toxicity (Nitrite) and greater competition for oxygen and Nutrition
(Nitrate). The main economic niches to suffer adversely from excessive Nitrogen levels are
persons engaged in mariculture, commercial fishing, hobbiest fisherman or persons engaged in
scientific studies. These sectors are the main focus of this project but people engaged in
tourism and provision of amenities may also be effected.
These problems are occurring at a time when classical agriculture is being put under increasing
pressure. Growth of world population and hence food requirements, the non-sustainability of
classical agriculture, pollution produced by agriculture, and the emphasis being put on fish
consumption promotion by the FAO all indicate that aquaculture is an excellent alternative as a
source of food.
At present there is no in-situ or on-line testing capability available to measure total Nitrogen in
marine waters. An opportunity has been recognised by the consortium partners, all of whom
are currently involved in environmental sensing, signal trasmission and pollution control to
produce a low cost sensor array to measure all of the above mentioned analytes simultaneously