Ecomare

Besides water, the rivers also dump silt particles, nutrients and pollution into the North Sea. The supply of fresh water via the rivers fluctuates per season as well as per year. This fluctuation influences the salinity gradient in the coastal waters. The supply of silt via the rivers, as far as amount is concerned, is much less than what flows in via the Atlantic Ocean. However, the river silt as well as the water itself was often strongly contaminated with all kinds of pollution, such as heavy metals.

Between 1969 and 1982, chemical waste was burned in the North Sea. Annually, it concerned one hundred thousand tons of liquid waste containing dangerous organic chloride compounds, originating from the chemical industries.
Incineration at sea occurred primarily with waste products deemed too risky to burn on land in the former processing installations. The burning of organic chlorinated compounds produces hydrochloric gasses. If the incineration took place on land, it would be extremely harmful for the environment and human health. At sea, the hydrochloric gas is quickly neutralized by the seawater.
The incineration vessels, such as the Vulcanus and the Vesta, were equipped with identical incineration ovens. Incineration took place at temperatures ranging from 1300 to 1400 degrees Celsius. Nevertheless, there were always waste products left over which would not burn or new materials were formed in the cloud of smoke. Burning waste at sea formed a tremendous source of pollution in the marine environment. Greenpeace and other environmental organizations carried on campaign for years against the use of incineration vessels.
At the Third Ministers Conference in 1990, the Ministers of the North Sea countries agreed to forbid incineration of waste in the North Sea per 31 December 1991. On 23 July 1990, the decision to end incineration of waste materials at sea was adopted by the OSPARCOM, making the ban legal for the entire Northeast Atlantic sea region.
The Netherlands had already stopped with incineration of Dutch wastes at sea in August 1989.

Besides water, the rivers also dump silt particles, nutrients and pollution into the North Sea. The supply of fresh water via the rivers fluctuates per season as well as per year. This fluctuation influences the salinity gradient in the coastal waters. The supply of silt via the rivers, as far as amount is concerned, is much less than what flows in via the Atlantic Ocean. However, the river silt as well as the water itself was often strongly contaminated with all kinds of pollution, such as heavy metals.

Between 1969 and 1982, chemical waste was burned in the North Sea. Annually, it concerned one hundred thousand tons of liquid waste containing dangerous organic chloride compounds, originating from the chemical industries.
Incineration at sea occurred primarily with waste products deemed too risky to burn on land in the former processing installations. The burning of organic chlorinated compounds produces hydrochloric gasses. If the incineration took place on land, it would be extremely harmful for the environment and human health. At sea, the hydrochloric gas is quickly neutralized by the seawater.
The incineration vessels, such as the Vulcanus and the Vesta, were equipped with identical incineration ovens. Incineration took place at temperatures ranging from 1300 to 1400 degrees Celsius. Nevertheless, there were always waste products left over which would not burn or new materials were formed in the cloud of smoke. Burning waste at sea formed a tremendous source of pollution in the marine environment. Greenpeace and other environmental organizations carried on campaign for years against the use of incineration vessels.
At the Third Ministers Conference in 1990, the Ministers of the North Sea countries agreed to forbid incineration of waste in the North Sea per 31 December 1991. On 23 July 1990, the decision to end incineration of waste materials at sea was adopted by the OSPARCOM, making the ban legal for the entire Northeast Atlantic sea region.
The Netherlands had already stopped with incineration of Dutch wastes at sea in August 1989.

The OSPAR convention of 1992 provided a ban on discharging most litter and other materials. Only dredged materials, litter from fish production, non-harmful material of natural origin, airplanes and ships are still allowed to sometimes dump in sea. Since January 1 1999, it has become forbidden to discharge sewage sludge in sea. Only Norway and England dump natural materials, and those amounts are declining rapidly (300,000 tons in 1994 was less than 10% of the discharged amount in 1990). Iron and steel ship wrecks are no longer allowed to be sunk, and there will be a ban on sinking all ships as of 2004. Discarded oil rigs must be removed in theory, although the underwater constructions from steel rigs weighing more than 10,000 tons are allowed to stay put, just like cement islands. In all cases, polluted materials must be removed from the installations.