Environment Agency - Home

Dangerous Substances Directives

Controls the levels of dangerous substances going into inland, coastal and territorial waters.

The Dangerous Substances Directive (76/464/EEC) and its 'daughter' directives control discharges that are liable to contain dangerous substances and that go to inland, coastal and territorial surface waters. Dangerous substances are toxic substances that pose the greatest threat to the environment and human health.

The directive specifies two lists of Dangerous Substances. List I covers those which are particularly toxic, persistent, and which may tend to accumulate in the environment. List II covers substances whose effects are still toxic, but less serious.

The directive requires that we eliminate pollution by List I substances and minimise pollution by List II substances. To do this, all discharges that are liable to contain dangerous substances must be authorised. The directive also specifies some requirements for environmental monitoring.

We define pollution by dangerous substances as exceedence of Environmental Quality Standards (EQSs) in the water. We base the EQS of a substance on the toxicity of the substance. It defines a concentration in the water below which we are confident that the substance will not have a polluting effect or cause harm to plants and animals. If the concentration in the water is less than the EQS then we have eliminated pollution. The 'daughter' directives set the EQSs for List I substances across Europe. Each country in the EU is required to set its own EQSs for List II substances.

Dangerous substances can potentially harm our health, aquatic life and water quality. They include certain industrial chemicals, pesticides and metals. They are not only found in sewage and trade discharges, but water passing through contaminated land and old mines can wash dangerous substances out into the environment. Rainwater runoff from roads and some industrial sites can also release dangerous substances into watercourses.

  • Read the directive

    Directive 2006/11/EC on pollution caused by certain dangerous substances discharged into the aquatic environment of the community.

  • Defra's chemicals pages

    Defra's chemicals pages are a source of information on what the Government is doing to protect the environment from the risks posed by exposure to hazardous chemicals