Report No DWI0225

Jul 1984

Under the EC Dangerous Substances Directive, Member States are required to reduce pollution of both fresh and salt waters, resulting from the discharge of List II substances, by the Environmental Quality Objectives (EQO) approach. The Department of the Environment have contracted the Water Research Centre to recommend Environmental Quality Standards (EQSs) for selected List II substances. This report is one of eleven prepared in fulfilment of this contract.

The chemistry of sulphides in water is reviewed. EQSs have been recommended for the protection of fish and other aquatic organisms in fresh and salt waters. There are no data for the toxicity of sulphides to marine fish and it is assumed that the EQS for other marine life will afford adequate protection. Unfortunately this EQS is itself based on very poor data. An EQS has also been recommended for recreational and amenity waters because of the potential aesthetic problems arising from the pungent smell of hydrogen sulphide.

There are very few data on environmental concentrations of sulphides and it has not been possible to compare the EQSs proposed on the basis of the literature information with field observations. The EQSs are therefore tentative.

The recommended EQS values are summarised in an annotated table. Sulphides are seldom the sole cause of water pollution in the UK and it seems unlikely that these proposals will cause an increase in the cost of monitoring the quality of UK waters.

Copies of this report may be available as an Acrobat pdf download under the 'Find Completed Research' heading on the DWI website.