Chromium; Copper; Lead;
Mercury;
Nickel; Zinc;
Organotins: Tributyltin (TBT), Dibutyltin (DBT); Polychlorinated biphenyls (PCBs);
Polycyclic Aromatic Hydrocarbons (PAHs); and Petroleum hydrocarbons.
8.4.3 Impact Assessment Methodology 40.
41.
The assessment of impacts within this chapter follows the general methodology set out in Chapter 6 EIA Methodology.
The assessment of water quality impacts is based on the standards outlined in the WFD and Dangerous Substances Directive, or comparison of concentration to the baseline environment where possible (for example in relation to suspended solid concentrations).
42.
The context of the contaminants found within the sediments of the East Anglia THREE site is established through the use of recognised guidelines and action levels. These are:
43. Cefas Action Levels for the disposal of dredged material (Cefas 2000); and
Canadian Sediment Quality Guidelines for the Protection of Aquatic Life (Canadian Council of Ministers of the Environment 2002).
The Cefas Action Levels are used as part of a ‘weight of evidence’ approach to assessing the suitability of material for disposal at sea, but are not themselves statutory standards. The majority of the materials assessed against these standards arise from dredging activities. These Action Levels are used in conjunction with a range of other assessment methods (e.g. bioassays) and data to assess risk to the environment. Selected current Action Levels are set out in Table 8.4.
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 8 Marine Water and Sediment Quality Page 15
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