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5 Environmental Standards
5.1 Introduction
As the national public body responsible for
environmental protection and improvement in Scotland, The
Scottish Environment Protection Agency's (
SEPA), powers and duties involve
regulating discharges into water, air and land and
implementation of
EC Directives.
5.2
EC Bathing Water Directive (76/160/
EEC)
A specific issue raised in the research specification
was the valuation of decrease in Bathing Water Quality. The
EC Bathing Water Directive (76/160/
EEC) calls for samples to be taken on
bathing water,
defined as fresh- or sea- water where bathing is either
explicitly authorised or is not prohibited and is
traditionally practised by a large number of bathers.
Scotland has identified 60 bathing waters to the European
Commission. 20 samples are taken at each bathing water
throughout the bathing season, 1 June to 15 September. The
Microbiological standards are shown in Table 5-1 .
Fifty-six of the bathing waters met required European
mandatory standards one fewer than in 2003 which was a
record year with only 34 of these managing to achieve the
more rigorous guideline standard a drop from 41 in 2003,
which was a drier year.
Table 5-1 Microbiological
quality standards for Bathing waters
Level of pass | Interpretations | Total coliforms | Faecal coliforms | Faecal streptococci |
|---|
Pass -Guideline | | 80% of samples should not exceed 500 total
coliforms per 100 ml. | 80% of samples should not exceed 100 faecal
coliforms per 100 ml. | 90% of samples should not exceed 100 faecal
streptococci per 100 ml. |
|---|
| Based on 20 samples: | Must have at least 16 samples with less
than, or equal to, 500 total coliforms per 100
ml. | Must have at least 16 samples with less
than, or equal to, 100 faecal coliforms per 100
ml. | Must have at least 18 samples with less
than, or equal to, 100 faecal streptococci per
100 ml. |
|---|
Pass -Mandatory | | 95% of samples should not exceed 10,000
total coliforms per 100 ml. | 95% of samples should not exceed 2,000
faecal coliforms per 100 ml. | The Directive contains no mandatory standard
for faecal streptococci. |
|---|
| Based on 20 samples: | Can only have 1 sample with greater than
10,000 total coliforms per 100 ml. | Can only have 1 sample with greater than
2,000 faecal coliforms per 100 ml. | The Directive contains no mandatory standard
for faecal streptococci. |
|---|
Table notes: The samples measure species of bacteria
that are known indicators of contamination of sewage
The Bathing Water Directive allows for resampling during
abnormal weather conditions. The rationale behind the
relaxation is that the bacteria sampled are indicator
species only, the source of the bacteria could be from
untreated or poorly treated sewage or from surface run off
from agricultural or urban areas. The surface run off or
diffuse pollution can contain bacteria from animals or
birds that can cause a bathing water to fail. Sewage
overflows are allowed up to three spills a year and on old
combined systems these are most likely to occur during poor
weather.
The published records
16 show that 31 sites were resampled after abnormal
weather in the flood event on the 11 and 12 of August.
SEPA also record that 2004 was a record
year for resampling of bathing waters requiring a total of
41 resamples.
5.3 Discharges to water
SEPA maintain a register of consents
which is a pubic register and available for inspection at
their offices. This shows the location type and level of
discharge allowed at a point of discharge. These are
sampled occasionally to check for compliance with the
discharge consent.
During flood events discharges that contain surface
drainage such as combined sewers will often exceed their
discharge consent. However under these conditions the flows
in the receiving watercourse may be high and sampling may
not be possible and dilution rates much higher than
normal.
Diffuse pollution from overland run off increases
dramatically during flood events and this may contribute to
a general degradation of the water habitats.
A comparison of annual reporting by
SEPA for lengths of watercourse with
good water quality standards reveals information for
previous years that may establish the importance of this
analysis. Their Annual report for 2003-2004
17 suggest that water quality in estuaries declined
slightly in 2003-2004 as 2002 was wetter and wet conditions
improved water quality conditions in estuaries. Flooding or
wet conditions could contribute to improvements in
estuaries and degradation
18 in rivers. Establishing costs associated with changes
in water quality are not straightforward most records
record chemical discharges and river quality is currently
assessed using biological standards.
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