Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, for what reason his Department has not adopted sediment quality guidelines to provide an assessment of levels beyond which heavy metal contamination may pose a risk to aquatic biota and human health.

The Environment Agency assesses the risk from heavy metals in freshwater, estuaries and coasts on the basis of Environmental Quality Standards (EQS). These are mostly based on water concentrations and for some substances they are based on the fraction of the metal known to be the most toxic to aquatic life. The EQS for mercury, for example, is based on concentrations of the metal in the tissues of aquatic animals. This allows direct assessment of the amount accumulating in the food chain which may present a risk to biota and higher predators that eat them, which is also protective of human health.

The Secretary of State has the powers to update EQSs in future in light of new scientific knowledge and so, whilst we have not adopted sediment quality guidelines for heavy metals in the freshwater environment at this stage, Defra will keep this under review.

In the marine environment, sediment assessment levels are in place for a range of contaminants, including heavy metals, that are used to enable risk assessments of the potential impacts to marine life such as fish and seabed organisms. Sediment action levels exist to inform the management of the sediment such as the disposal of dredged sediment to sea.