e-Digest Statistics about: Coastal and marine waters
Bathing waters
The microbiological quality of bathing waters can be affected by diffuse pollution from agricultural and urban sources, discharges of sewage effluent, storm water overflows and river borne pathogens (i.e. pollutants that could affect human health).
Under the EC Bathing Water Directive, eleven physical, chemical and microbiological parameters are measured including mineral oils, phenols and surface active substances as well as total and faecal coliforms, which are generally considered to be the most important indicators of the extent to which water is contaminated by faecal material. Samples of bathing water are taken at regular intervals two weeks before and then during the bathing season, which usually covers the period from mid-May to end-September in England and Wales, and from the beginning of June to mid-September in Scotland and Northern Ireland. In the United Kingdom a minimum of 20 samples are normally taken at each site.
The Directive sets mandatory standards for a number of the parameters. The mandatory limit value for total coliforms is 10,000 per 100 ml, and for faecal coliforms 2,000 per 100 ml. For a bathing water to comply with the mandatory microbiological standards, the Directive requires that at least 95 per cent of samples taken for each of these parameters over the bathing season are less than or equal to the mandatory values. In practice this means that where 20 samples are taken, a maximum of only one sample may exceed the mandatory value for the bathing water to comply, and where less than 20 samples are taken none may exceed the mandatory value for the bathing water to comply.
The Directive also sets more stringent guideline standards. The EC assess guideline compliance in accordance with the tighter limit values including faecal coliforms (100 per 100ml) and total coliforms (500 per 100ml). At least 80 per cent of bathing water samples must meet the limit values and the mandatory standard to achieve guideline compliance (Referred to here as 'Commission Guideline').
In the UK, guideline compliance is additionally assessed against a faecal streptococci limit value of 100 per 100ml. At least 90 per cent of bathing water samples must comply with this additional standard (Referred to here as 'Guideline'). Compliance with the UK assessment of guideline compliance is required to fulfil the water criterion of the international Blue Flag award scheme.
Table 1a summarises the results for compliance with the mandatory microbiological standards and Table 1b summarises the results for compliance with the guideline microbiological standards. Both tables show compliance for each region in recent years. There was a noticeable rise in the levels of compliance in Scotland, England and Wales during the mid-1990s. This was the result of higher treatment standards, the re-siting of discharge outfalls and a reduction in combined sewer overflows under the bathing water improvement programme. Over 1 billion pounds has been spent over the last decade, through the water company spending programme on water quality improvements which has been driven by the requirements of the Bathing Water Directive.
The data shows that the percentage of coastal bathing beaches reaching mandatory standards in the United Kingdom improved from 77 per cent in 1990 to 96.5 per cent in 2007 and the percentage complying with guideline standards increased from 29 percent to 71.3 per cent between 1994 and 2007. The data also shows sample compliance in each Environment Agency region in England and Wales as well as Scotland and Northern Ireland.
Table 2 gives an overall indication of the consistency with which bathing waters have complied with the mandatory coliform standards over the last five years bathing seasons.
More detailed information covering the results for each individual bathing water in the United Kingdom is given in Table 3, Table 4 and Table 5. Table 3 shows whether individual bathing waters passed mandatory, Commission guideline or UK guideline microbiological standards in each of the last nineteen years 1988-2007. Table 4 gives more information about total and faecal coliform samples taken at each bathing water in 2007, including the number of samples taken, and the number of samples that failed to conform. Table 5 gives information for eight other bathing water quality parameters for which the Directive specifies mandatory values, for each bathing water.
Future Developments
In the future standards for bathing water quality will be even tighter following the adoption of a revised Bathing Water Directive (2006/07/EC) in March 2006. The new Directive updates the way in which water quality is measured, focusing on fewer microbiological indicators, with water quality classifications carried out over 3 or 4 years. There are four new classification categories: poor, sufficient, good and excellent. The Directive will also require specific information to be provided to the public, both on signs at beaches and online.
It is likely that monitoring under the new system will begin in 2012 and all bathing waters will be required to achieve at least 'sufficient' by 2015, which is much more stringent than the current mandatory standard.
A consultation paper was issued on 12 November 2007 outlining Defra's proposals for the implementation of the revised Bathing Water Directive. The new Directive will update the way in which water quality is measured and will use four new classification categories: poor, sufficient, good and excellent. The Directive will also require specific bathing water information to be provided to the public, both on signage at beaches and online.
The consultation will close on 4 February 2007. Further details can be found at this consultation section of Defra website
Regional data
Where practical the data presented here is shown in Environment Agency regions. Data by local authority can be found on the What's in your backyard' section of the Environment Agency internet site.
Further Information:
- Data Tables:
- 1a Bathing water surveys, mandatory standards: 1988-2007 XLS
- 1b Bathing water surveys, guideline standards: 1990-2007 XLS
- 2 Five year record of compliance with EC Bathing Water Directive for mandatory coliform : 2002-2007 XLS
- 3 Bathing Waters Survey - compliance with Bathing Water Directive for coliform standards: 1988-2007 XLS
- 4 Bathing Waters Survey - Bathing Water Directive for microbiological mandatory and guideline standards: 2007 XLS
- 5 Bathing Waters Survey - compliance with Bathing Water Directive mandatory standards for other parameters: 2007 XLS
- Internet Links:
- e-digest: Beaches
- e-digest: Coastal and marine waters
- Defra: Bathing Water policy pages
- Europa: Water Quality in the European Union
- England and Wales: Environment Agency - Bathing water quality
- Scotland: Scottish Environment Protection Agency (SEPA) - Bathing water reports
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Page last modified: 14 November 2007
Page published: 14 November 2007