Marine: Cleaner Seas report
Inputs from land
What do we put into the seas?
Material reaches the seas through natural processes and human activities (e.g. industrial, domestic and agricul-tural). Substances such as nitrogen, phosphorus, complex organic compounds and pesticides enter marine waters via rivers and the atmosphere, and from direct discharge.The most important source of inputs from land-based sources is rivers and coastal discharges. In the North Sea these make up about 40% of total inputs. Other sources include emissions to the atmosphere. These contribute about 30% of the total input to the North Sea.
Research suggests that naturally induced changes in population of marine species, and the direct impact of anthropogenic activities, such as fishing, are far more significant in holistic terms than the effects of contaminant inputs.
Major rivers that discharge into the North Sea include the Rhine, the Elbe, the Weser, the Scheldt, the Forth, the Ouse, the Trent, and the Thames.
The Rhine serves some of the main industrial areas of Germany and parts of France, the Netherlands and Switzerland. The Weser and Elbe link heavily industrialised areas of the former East Germany with the German Bight. All these rivers carry drainage from land and effluents from sewage works and industry. In Britain the Ouse and Trent serve an area with over 10 million people, and a quarter of UK industrial output.
The Rhine accounts for between 40% and 50% of all the substances that enter the North Sea by river. UK rivers in total account for about 20%.
North Sea Inputs
(Part of OSPAR Region II)
1A. UK east coast. Includes all UK rivers and direct inputs from
Thames Estuary to Cape Wrath on the north coast of Scotland
2. German coast. Includes inputs from rivers Elbe, Weser and Ems
3. Dutch coast. Includes the rivers Rhine and Meuse. Data on Lindane
and direct inputs are limited
4. Belgian coast. Includes river Scheldt. No direct inputs data
available
The Channel
(Part of OSPAR Region II)
1B. UK south coast. Includes all UK rivers and direct inputs from
Kent to Cornwall
5. French channel coast. Only limited riverine data available
The Celtic Seas
(OSPAR Region III)
1C. UK Celtic Sea coast. Includes all UK rivers and direct inputs
from Lands' End to St Brides Bay
1D. UK Irish Sea and Atlantic coast. Includes all UK rivers and
direct inputs from Cardigan Bay to Cape Wrath and from Northern Ireland
6. Republic of Ireland. Riverine inputs from all coastal areas.
Data for mercury is limited. No data for lindane. No direct inputs data
available
Average annual inputs of a nutrient (total nitrogen), a heavy metal (mercury)
and a pesticide (lindane) to the seas around the UK and Ireland from rivers
(R) and, where the data are available, from direct effluent discharges
to saline waters (D).
Estimates are based on annual input estimates reported to OSPAR for the
period 1990 - 1995. Where any such estimate has been reported as a range,
a mean value is used.
Page last modified:
01 March 2005
Page published: 21 September 1988