A.R.D. Stebbing . R.I. Willows
The approach uses measures of the biological impact of contaminant loading, rather
than attempting to assess the health of the system by monitoring each chemical or class
of chemical contaminant. We advocate monitoring in terms that relate directly to the
criteria used to gauge environmental health. We will consider the capacity of the North
Sea as a whole to assimilate wastes and effluents, and in the light of recent data (post 1990)
which demonstrate that it is being exceeded. Since the work of the regulatory authorities is to monitor the conformation of contaminant concentrations to pollution legislation, we ask whether the present statutory controls and approach to monitoring are
appropriate for their purpose.
8.2
The North Sea
8.2".1
Inputs and Outputs of Contaminants
The North Sea is a centre of intense human activity for eight west European countries,
for it is their only access to the sea for shipping, oil and mineral wealth, and fishing.
The North Sea provides an environmental service by accepting the industrial, agricultural and societal wastes and effluents from the 164 million people that live on its shores
and in the catchment of the rivers that flow into it. Such inputs are likely to challenge
the capacity of the environment to sustain the indigenous biota by their volume, if not
their toxicity.
The catchment area of the rivers flowing into the North Sea is 850000 km>, compared with its surface area of 575000 km 2 • It has a volume of 93 830 km 3 and receives a
variable run-off from these rivers of 296-354 km 3 a-'. The catchments of the major rivers are densely populated and heavily industrialized, providing the main anthropogenic
inputs (contaminants and nutrients) to the North Sea. The river basins of the Thames,
Humber, Elbe, We$er, Rhine, ScheIdt and Seine are the most densely populated (statistics are drawn from ICES (1983) and Quality Status Report for the North Sea 1993). The
North Sea (Fig. 8.1a) is bounded on three sides by land with its principle exchange with
the Atlantic to the North and a minor route for exchange via the Dover Straits to the
south. It is a shallow sea (30-200 m), less so in the south, such that the volume of water
that can dilute estuarine inputs is greater for those rivers that flow into the northern
North Sea (rivers Forth and Tyne) than in the south (rivers Thames and Rhine).
While the North Sea can be considered as a semi-enclosed system flushed by relatively
clean waters from the North Atlantic, its northern open boundary is also a route by
which contaminants may be imported and exported. Input via this route is well illustrated by radioisotopes originating from Sellafield and Dounrey (Kautsky 1988). The Norwegian coastal current provides the major outflow of all water from the North Sea and the
Baltic, originating in the Skagerrak and hugging the coast of Norway as it moves north.
The stronger tidal flows (Fig. 8.1a) are coastal, with weak and variable currents in
the central North Sea. The dominant residual flows are from north to south along the
UK East Coast with a reciprocal flow northward along the European coast towards the
Skagerrak, supplemented by an input via the Dover Straits. Current speeds fall as the
northward flowing currents slow at the entrance to the Skagerrak and Kattegat, before
returning to the North Atlantic.
The approach uses measures of the biological impact of contaminant loading, rather
than attempting to assess the health of the system by monitoring each chemical or class
of chemical contaminant. We advocate monitoring in terms that relate directly to the
criteria used to gauge environmental health. We will consider the capacity of the North
Sea as a whole to assimilate wastes and effluents, and in the light of recent data (post 1990)
which demonstrate that it is being exceeded. Since the work of the regulatory authorities is to monitor the conformation of contaminant concentrations to pollution legislation, we ask whether the present statutory controls and approach to monitoring are
appropriate for their purpose.
8.2
The North Sea
8.2".1
Inputs and Outputs of Contaminants
The North Sea is a centre of intense human activity for eight west European countries,
for it is their only access to the sea for shipping, oil and mineral wealth, and fishing.
The North Sea provides an environmental service by accepting the industrial, agricultural and societal wastes and effluents from the 164 million people that live on its shores
and in the catchment of the rivers that flow into it. Such inputs are likely to challenge
the capacity of the environment to sustain the indigenous biota by their volume, if not
their toxicity.
The catchment area of the rivers flowing into the North Sea is 850000 km>, compared with its surface area of 575000 km 2 • It has a volume of 93 830 km 3 and receives a
variable run-off from these rivers of 296-354 km 3 a-'. The catchments of the major rivers are densely populated and heavily industrialized, providing the main anthropogenic
inputs (contaminants and nutrients) to the North Sea. The river basins of the Thames,
Humber, Elbe, We$er, Rhine, ScheIdt and Seine are the most densely populated (statistics are drawn from ICES (1983) and Quality Status Report for the North Sea 1993). The
North Sea (Fig. 8.1a) is bounded on three sides by land with its principle exchange with
the Atlantic to the North and a minor route for exchange via the Dover Straits to the
south. It is a shallow sea (30-200 m), less so in the south, such that the volume of water
that can dilute estuarine inputs is greater for those rivers that flow into the northern
North Sea (rivers Forth and Tyne) than in the south (rivers Thames and Rhine).
While the North Sea can be considered as a semi-enclosed system flushed by relatively
clean waters from the North Atlantic, its northern open boundary is also a route by
which contaminants may be imported and exported. Input via this route is well illustrated by radioisotopes originating from Sellafield and Dounrey (Kautsky 1988). The Norwegian coastal current provides the major outflow of all water from the North Sea and the
Baltic, originating in the Skagerrak and hugging the coast of Norway as it moves north.
The stronger tidal flows (Fig. 8.1a) are coastal, with weak and variable currents in
the central North Sea. The dominant residual flows are from north to south along the
UK East Coast with a reciprocal flow northward along the European coast towards the
Skagerrak, supplemented by an input via the Dover Straits. Current speeds fall as the
northward flowing currents slow at the entrance to the Skagerrak and Kattegat, before
returning to the North Atlantic.