Report No DWI0220

Apr 1985

Under the EEC 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. DOE have contracted WRC to recommend Environmental Quality Standards (EQSs) for selected List II substances. This report is one of a series of fourteen produced in fulfilment of the contract.

Common uses of iron are discussed and the chemistry of iron in water reviewed. Information is presented on the concentration of iron in the environment, with emphasis on UK and European waters and biota.

EQS values are recommended for all the agreed uses of water (as discussed in TR 206). EQSs for the protection of fish and other aquatic organisms in both fresh and salt waters have been proposed on the basis of literature reviews, which are presented as separate Annexes. Suitable information is limited, especially for salt-water species.

The recommended EQS values for all uses are summarised in an annotated Table and for comparison water quality standards from other countries are also tabulated.

Iron may affect fauna and flora directly or indirectly when sedimentation of particulate iron may cover natural substrates eliminating ecological niches. In this report EQSs are proposed on observations of direct effects. Problems arising from excessive sedimentation are dependent on the dilution and current velocities of the receiving water and it has only been possible to give limited guidance in relation to the control of discharges.

In freshwaters the commonest source of iron-rich discharges is old mine waters and runoff from colliery spoil. The EQSs proposed are applicable to these discharges; however, extension of existing controls will be limited to those areas where responsibility for discharge can be clearly identified.

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