Background levels of toxic substances


This Appendix is intended to provide some background information on concentrations found for some of the toxic substances considered in this report during systematic surveys undertaken in recent years. Other information on "typical" concentrations found for many contaminants is given in the individual profiles in Appendices B and C. However, this summary is not exhaustive and readers are advised to contact the Environment Agency/SEPA area or regional offices for advice on more recent survey information.

Two major reviews: 'National Monitoring Programme. Survey of the Quality of UK Coastal Waters' (prepared by the Marine Pollution Monitoring Management Group) (MPMMG 1998) and 'Pesticides in the Aquatic Environment, 1995' (prepared by the National Rivers Authority) (TAPS 1995) have been published which present summary information on the concentrations of various toxic chemicals in UK estuarine and coastal waters.

The National Monitoring Programme (NMP) was initiated in the late 1980s to co-ordinate marine monitoring in the UK between various regulatory organisations (and their predecessors). The results from the first phase of the NMP was intended to establish the spatial distribution of contaminants in UK marine waters and to define their biological status. A survey of 87 estuarine, intermediate and offshore sites was carried out between 1992 and 1995 to determine the distribution of contaminants (including metals and organic substances) in a range of matrices (water, sediments, shellfish and fish).

The report 'Pesticides in the Aquatic Environment, 1995' (prepared by the National Rivers Authority) (TAPS 1995) presents information on the concentration of various toxic substances in the estuarine and coastal waters of England and Wales. In 1995, the NRA monitored 101 pesticides and recorded almost 35,000 results in estuaries and coastal waters from 413 sites (TAPS 1995). The data were recorded as the number of samples that exceeded 0.1 mg l-1, with no further information available on the highest concentrations reported.

A more recent report has been published (Environment Agency 1999) and readers are referred to this document for updated information on pesticides contamination of estuary and coastal waters.

Water Column Concentrations

Sediment Concentrations

Biota Concentrations