Abstract

Project aims
Defra is seeking to understand the magnitude of risks (e.g. to aquatic ecology and human health) or
impacts (e.g. on the way that water bodies are managed) posed by contaminated sediment in England,
as part of its work towards meeting its environmental objectives.
In the context of this project, in-situ contaminated sediment is defined as:
Chemically contaminated sediment within the water column, bed, banks and floodplain of a surface
water body that has been transported alongside the normal sediment load and deposited by fluvial
or coastal processes.
This project considers the risk posed by non-agricultural diffuse pollution sources in England that result
in the contamination of in-situ sediments (for example, contamination from toxic metals, hydrocarbons
and surfactants). The scope encompasses both freshwater and marine sediments in England and
extends to one nautical mile off-shore (the seaward limit of coastal waters under the Water Framework
Directive (WFD) in England).
Previous national strategies, including the 2007 Defra UK Strategy for Managing Contaminated Marine
Sediments (CDMS), focussed on characterising the risks associated with contaminated sediments in
the marine environment. However, while extensive research has been carried out in many locations
(including as part of WFD implementation studies) and for particular sources of contamination (e.g.
historical metal mining; Environment Agency, 2008) there has not been a comprehensive overview of
sediment contamination on a national scale. This project seeks to build on the existing evidence base,
drawing together information on the freshwater environment to complement that already gathered for
marine waters. This project’s overall aim is to provide a sound evidence base on the contamination of
in-situ sediments, which can underpin the development of tools and methods that will help Defra, the
Environment Agency and other bodies engaged in regulation and protection of water quality.