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National Shellfish Sanitation Program
Guide for the Control of Molluscan Shellfish
2003
Guidance Documents
Chapter II. Growing Areas
.01 Total Coliform Standards
Table of Contents
@.02 Bacteriological Standards
Note: The National Shellfish Sanitation Program (NSSP) allows
growing areas to be classified using either a total or fecal coliform
standard. The NSSP further allows the application of either standard to
different water bodies within the state. Once properly classified
applying either standard for classification, the NSSP allows the use of
the adverse pollution condition or the systematic random sampling
strategy for routine classification monitoring as appropriate to the
situation in the growing area. For maximum flexibility, a state may
wish to adopt the use of both standards and both monitoring strategies
as appropriate with each standard. At the Interstate Shellfish
Sanitation Conference's annual meeting in 1992, Task Force II
recommended that this portion of the Model Ordinance be
codified according to the standard used and the monitoring strategy
employed. The Model Ordinance has subsequently been
recodified in this manner. This codification represents the delineation
of the standards based on total coliforms. The division of the
standards based on fecal coliforms is outlined in the main body of the Model
Ordinance (Chapter IV).
A. General. Either the total coliform or
fecal coliform standard shall be applied to a growing area.
B.
|
Sampling Stations. The Authority
shall
ensure that the number and location of sampling stations is adequate to
effectively evaluate all pollution inputs into the growing area. |
C. Exceptions.
(1) |
Except for growing areas
classified
as prohibited, in any growing area where there are nonpoint pollution sources
which impact the water quality, a minimum of 30 samples, collected
under various environmental conditions, shall be required to classify a
growing area not previously classified under Chapter IV @ .03.
|
(2)
|
Except for growing areas
classified
as prohibited or when systematic random sampling is applied in growing areas
where there are no pollution sources having an effect on the water quality,
a minimum of 15 samples shall be required to classify any growing area
not previously
classified
under
Chapter
IV
@ .03 when
there are no pollution sources impacting the water quality.
|
(3) |
The Authority is not required to
apply the total coliform standard if a detailed study verified by
laboratory findings demonstrates that the coliforms recovered from the
growing area are not of direct fecal origin and do not indicate a
public health hazard. |
D. Standard for the Approved Growing Area
Classification in the Remote Status.
(1) |
Water Quality. The
bacteriological quality of every station in the growing area shall meet
the total coliform standard below.
|
(2)
|
Total Coliform Standard for the
Remote Status. The total coliform geometric mean MPN of the water
sample results for each sampling station shall not exceed 70 MPN per
100 ml; and not more than 10% of the samples shall exceed an MPN of:
(a) |
230 MPN per 100
ml for a 5-tube, decimal dilution test;
|
(b) |
330 MPN per 100 ml for
a 3-tube, decimal dilution test; or
|
(c) |
140 MPN per 100
ml for the 12-tube, single dilution test.
|
|
(3) |
Required Sample Collection.
(a) |
A minimum of 2
samples per sampling station shall be collected annually.
|
(b) |
A minimum of the most
recent 15
samples collected per sampling station shall be used to calculate the
geometric mean and 10% criteria of the data to determine compliance
with the standard established for the approved classification of remote
growing areas. |
|
E. Standard for the Approved
Classification of Growing Areas Affected by Point Source Pollution.
(1) |
Water Quality. The
bacteriological
quality of every station in the growing area shall meet the total
coliform standard in
E §.(2)
|
(2)
|
Total Coliform Standard
for Adverse Pollution Condition Monitoring. The total coliform
geometric mean MPN of the water quality sample results for each
sampling station shall not exceed 70 per 100 ml, and, not more than 10
% of the samples shall exceed an MPN of:
(a) |
230 MPN per 100 ml for a
5-tube,
decimal dilution test;
|
(b) |
330 MPN per 100 ml for a
3-tube,
decimal dilution test; or
|
(c) |
140 MPN per 100 ml for the
12-tube,
single dilution test.
|
|
(3) |
Required Sample Collection.
(a) |
A minimum of 5 samples
shall be
collected annually under adverse pollution conditions from each sample
station in the growing area.
|
(b) |
A minimum of the most
recent 15
samples collected under adverse pollution conditions from each sample
station shall be used to calculate the geometric mean and 10% criteria
of the data to determine compliance with this standard.
|
(c) |
Sampling station locations
shall be
adjacent to actual or potential sources of pollution. |
|
F. Standard for the Approved
Classification of Growing Areas Affected by Nonpoint Source Pollution.
(1) |
Exception. If the tidal stage
increases the total coliform concentration, the Authority shall use
sample results collected during that tidal stage to classify the area.
|
(2)
|
Pollution Sources. Harvest
waters
shall be:
(a) |
Impacted only by randomly
occurring, intermittent environmental events; and,
|
(b) |
Not impacted by discharges
from
sewage treatment facilities or combined sewer overflows.
|
|
(3) |
Water Quality. The
bacteriological
quality of every station in the growing area shall meet the total
coliform standard in §F (4) or §F (6) as appropriate to the
monitoring
strategy being used.
|
(4) |
Total Coliform Standard for
Systematic Random Sample Monitoring. The total coliform geometric mean
of the water sample results for each sampling station shall not exceed
70 MPN per 100 ml and the estimated 90th
percentile shall
not exceed an MPN of:
(a) |
230 MPN per 100 ml for a
5-tube,
decimal dilution test;
|
(b) |
330 MPN per 100 ml for a
3-tube,
decimal dilution test.
|
|
(5) |
Estimated 90th
Percentile. The estimated 90th percentile
shall be
calculated by:
(a) |
Determining the geometric
mean and
logarithmic (base 10) standard deviation for the sample result from
each sampling station; then
|
(b) |
Multiplying the log
standard
deviation in (a) by 1.28; and
|
(c) |
Adding the product from
(b) to the
log mean of sample results, and;
|
(d)
|
Taking the antilog of the
results
in (c) to get the estimated 90th percentile.
|
(e)
|
MPN values that signify
the upper
or lower range of sensitivity of the MPN test used in the 90th
percentile calculation shall be increased or decreased by one
significant digit.
|
|
(6)
|
Total Coliform Standard for
Adverse
Pollution Condition Monitoring. The total coliform geometric mean MPN
of the water sample results for each sample station shall not exceed 70
MPN per 100 ml and not more than 10% of the samples shall exceed an MPN
of:
(a) |
230 MPN per 100 ml for a
5-tube,
decimal dilution test; or
|
(b) |
330 MPN per 100 ml for a
3-tube,
decimal dilution test; or
|
(c) |
140 MPN per 100 ml for a
12-tube,
single dilution test.
|
|
(7)
|
Required Sample Collection.
(a) |
Adverse Pollution
Condition
Monitoring. The Authority shall collect samples at the same frequency
as described in §E. (3) for application of the standard under §E. (2).
|
(b) |
Systematic Random Sample
Monitoring. The requirement for systematic random sample monitoring
shall be met when:
(i) |
Sample station
locations are
adequate to produce the data to effectively evaluate all nonpoint
sources of pollution;
|
(ii) |
Sample collection is
scheduled
sufficiently far in advance to support random collection with respect
to environmental conditions. Compliance requires that prior to
implementation, the schedule for random sampling shall be documented in
the master file for the growing area and adhered to. If conditions at
the time of scheduled sample collection are hazardous to the safety of
the individuals assigned to collect samples, sample collection shall be
rescheduled in accordance with provisions in the sampling schedule;
|
(iii) |
A minimum of 6
random samples
shall be collected annually from each sampling station in the growing
area; and
|
(iv) |
A minimum of the 30
most recent
randomly collected samples from each sampling station shall be used to
calculate the geometric mean and 90th percentile
to
determine compliance with this standard.
|
|
(c) |
Transition from Adverse
Pollution
Condition Monitoring to Systematic Random Sample Monitoring. If the
Authority:
(i) |
Does not have 30
recent randomly
collected sample results from each station, then the previous 15
samples collected under adverse pollution conditions may be used with
the most recent random samples to meet the minimum 30 sample
requirements for a transition period not to exceed 3 years; and
|
(ii) |
Uses the transition
period
described in (i), as additional random samples are collected, the
random samples shall chronologically replace the samples collected
under adverse pollution conditions (e.g. sample 31 replaces sample 1) |
|
|
G.
|
Standard for the Restricted
Classification of Growing Areas Affected by Point Source Pollution and
Used as a Shellfish Source for Shellfish Depuration.
|
(1) |
Water Quality. The
bacteriological
quality of every sample station in the growing area shall meet the
total coliform standard in §G. (2). |
(2)
|
Total Coliform Standard for
Adverse
Pollution Condition Monitoring. The total coliform geometric mean MPN
of the water sample results for each station shall not exceed 700 per
100 ml and not more than 10% of the samples shall exceed an MPN of:
(a) |
2,300 MPN per 100 ml for a
5-tube,
decimal dilution test; or
|
(b) |
3,300 MPN per 100 ml for a
3-tube,
decimal dilution test; or
|
(c) |
1,386 MPN per 100 ml for a
12-tube,
single dilution test.
|
|
(3) |
Required Sample
Collection. Samples shall be collected in accordance with §E. (3).
|
H.
|
Standard for the Restricted
Classification of Growing Areas Affected by Nonpoint Source Pollution
and Used as a Shellfish Source for Shellfish Depuration. |
(1) |
Exception. If the tidal stage
increases the total coliform concentration, the Authority shall use
samples collected under that tidal stage to classify the area.
|
(2)
|
Pollution Sources. Growing areas
shall meet the requirements in §F. (2).
|
(3) |
Water Quality. The
bacteriological
quality of every sample station in the growing area shall meet the
total coliform standard in §H. (4) or §H. (6) as appropriate
to the
monitoring strategy being used.
|
(4) |
Total Coliform Standard for
Systematic Random Sample Monitoring. The total coliform geometric mean
MPN of the water sample results for each sample shall not exceed 700
per 100 ml and the estimated 90th percentile
shall not
exceed:
(a) |
2,300 MPN per 100 ml for a
5-tube,
decimal dilution test; or
|
(b) |
3,300 MPN per 100 ml for a
3-tube,
decimal dilution test.
|
|
(5) |
Estimated 90th
percentile. The estimated 90th percentile
shall be
calculated by the same method described in §F. (5).
|
(6)
|
Total Coliform Standard for
Adverse
Pollution Condition Monitoring. The total coliform geometric mean MPN
of the water sample results for each station shall not exceed 700 MPN
per 100 ml and not more than 10% of the samples shall exceed an MPN of:
(a) |
2,300 MPN per 100 ml for a
5-tube,
decimal dilution test; or
|
(b) |
3,300 MPN per 100 ml for a
3-tube,
decimal dilution test; or
|
(c) |
1,386 MPN per 100 ml for a
12-tube,
single dilution test.
|
|
(7)
|
Required Sample Collection.
(a) |
Adverse Pollution
Condition
Monitoring. The Authority shall collect samples at the same frequency
as described in §E. (3). for application of the standard under
§H. (6).
|
(b) |
Systematic Random
Sample Monitoring. The Authority shall collect samples in the same
manner and at the same frequency as specified in §F. (7)(b) for
application of the standard under §H. (4). |
|