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The Biogeochemistry of Nutrients, Metals and Organic Micropollutants in the North Sea
www.belspo.be/belspo/fedra/proj.asp?l=en&cod=mn/dd1/001

More:  Institutes 
Parent project: Research action SPSD-I: Sustainable management of the North Sea, more
Reference no: MN/DD1/001
Period: January 1997 till December 2001
Status: Completed

Thesaurus terms: Biogeochemistry; Coastal waters; Nutrients (mineral); Pollutants; Volatile compounds
Geographical term: ANE, North Sea, Southern Bight [gazetteer]

Institutes (5)  Top 
  • Universiteit Antwerpen; Centrum voor Micro- en Sporenanalyse (MITAC), more
  • Université Libre de Bruxelles; Faculté des Sciences; Département des Sciences de la Terre et de l'Environnement; Unité Modélisation Biogéochimique Système Terre; Laboratory of Chemical Oceanography and Water Geochemistry (LoCGE), more
  • Vrije Universiteit Brussel; Faculteit Wetenschappen & Bio-ingenieurswetenschappen; Vakgroep Chemie; Onderzoeksgroep Analytische en Milieuchemie (ANCH), more
  • Universiteit Gent; Faculteit Bio-ingenieurswetenschappen; Vakgroep Organische chemie; Onderzoeksgroep Organische milieuchemie en -technologie (EnVOC), more
  • Belgian Science Policy (BELSPO), more, sponsor

Abstract:
There can be no doubt that men and their activities have weighed heavily on coastal areas in the last fifty years. In some respects, the situation may even continue to deteriorate which will further reduce their attraction. The discharge of waste, their carriage by the Scheldt and the deposit of atmospheric pollutants all constitute threats. There is, on the one hand, increasing eutrophication and a proliferation of algae resulting from the increased carriage by water of nitrogen and phosphorus and, on the other, the threat that the life of animals and plants will be reduced by contamination by heavy metals and micropollutants. The so-called "red tides", the dramatic proliferation of certain colonies of algae and mercury and cadmium pollution are already universally recognised. The purpose of this research project is to examine the principle means by which pollutants are carried to the North Sea and to track them once they reach it.


The Project

The atmosphere

Atmospheric flows of certain toxic metals, polychlorobiphenyls, polycyclic aromatic hydrocarbons and pesticides have already been studied for some time. However, with other significant groups of inorganic and organic pollutants and data on the interaction between the air and the sea currently either do not exist or else are unreliable. Everybody realises that atmospheric transport to the oceans is one of the principal sources of nutrients on a world-wide scale (such as nitrogen and bioavailable trace elements of which silicium is one) which play a vital part in primary production. Extremely high levels of deposit can have a profound effect on the ecosystem of the North Sea and, locally, in certain atmospheric conditions, produce excesses of algae. So far, no one has given it any thought in mathematical models. Consequently detailed and reliable data on the quantities of the main nutrients deposited by the atmosphere have to be gathered. This will involve monitoring based on location, season and the origins of the atmospheric mass above the North Sea.

A very significant part of organic contaminants is Volatile Organic Compounds (VOC), a large group of chemically different substances which have multiple and diverse effects. VOC affects atmospheric processes, some types are carcinogenic, others are persistent and have the effect of causing bioaccumulation. Nine types of VOC, all of them chlorinated, have been included in the list of the 36 priority toxic pollutants presented at the Third Conference on the North Sea. Consequently there will have to be research into their sources, concentrations and flows in the marine environment. A first monitoring campaign has shown that the Scheldt is a significant source of VOC in the marine environment. As regards these composites, it seems that there is a flow from the water into the air with the various places located in the centre of the continental plateau. On the occasion of outbreaks of algae, high concentrations of certain hydrocarbons were measured. Whatever causal relationship may exist between the proliferation of algae, increased concentrations and air/sea flows will have to be studied.

Where heavy metals are concerned, the level of atmospheric pollution above the North Sea seemed to rise when the wind was from the Southeast, for example, from Belgium. Airborne deposits of cadmium and lead equal those from rivers or direct outflows of industrial waste and wastewater. Quantities of zinc and lead, unlike other elements, seem to be decreasing. The great variations in concentrations and deposits have required taking a large series of measurements in order to establish reliable and accurate averages.
Another significant observation is that the main differences in the flow of deposits modelled and those measured are caused by particles which are relatively among the largest (>4µm) which are responsible for from 85 to 99% of dry deposits. Such particles settle rapidly and do not fly far. Since virtually all of the

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