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Blackman Bay & Blackman Bay East

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					                                Tasmanian Shellfish Quality Assurance Program
                                        Public & Environmental Health Service
                                               Division of Health Advancement




                   ANNUAL

              DATA REVIEW

                     for the


Blackman Bay & Blackman Bay East
                 Growing Areas




                 For year 2007




        Public & Environmental Health Service
  Department of Health and Human Services Tasmania
          GPO Box 125B, Hobart TAS 7001
      ANNUAL GROWING AREA DATA EVALUATION

GROWING AREA                     Blackman Bay & Blackman Bay East
GROWING AREA PERIOD                         Jan – Dec 2007
DATE OF EVALUATION                          February 2008
EVALUATED BY                                Alison Turnbull
SAMPLING STRATEGY                           Adverse Pollution Conditions
CURRENT CLASSIFICATION                      APPROVED (Blackman Bay),
                                            APPROVED CONDITIONAL (Blackman Bay
                                            East)
CRITICAL VALUES
Blackman Bay                     Not applicable,
Blackman Bay East                 >70mm rainfall at Nugent in 7 days will cause closure at
Blackman Bay East.



                             B'man 16

                                                        B'man Bay 20



                       B'man 1

                                        B'man 2                          B'man 4


                   B'man 8
                                                              B'man 12


                                            Blackman
                             B'man Bay 19   Bay
                                                                  Blackman Bay East



                                                                                   B'man Bay 21
                                             B'man 7
                                                        B'man Bay 18



Figure 1. Sample sites and leases in Blackman Bay


SHORELINE SURVEY UPDATE
TSQAP staff visited Blackman Bay on several occasions during 2007 and noted no
significant changes in land usage and no developments of significance on the
surrounding areas. As noted in previous reports the land surrounding Blackman Bay is
predominantly rural in nature with no large sub-divisions or industrial activities.

SAMPLE SITE CHANGES There have been no sample site changes since the last
triennial report for 2003-5. The sample sites and harvest zones are shown in figure 1
above.

DATA COLLECTED DURING 2007
(a) water quality data
 Growing area      Site         Date      7 day Rainfall   Salinity   Thermotolerant Growing Area
                                              (mm)                      coliforms       Status
                                                                         (/100ml)
Blackman Bay         1       06/03/2007       61.8          36.1            0.9         Open
Blackman Bay         1       08/10/2007        6.8          35.2            0.9         Open
Blackman Bay         1       19/10/2007        8.6          35.3            0.9         Open
Blackman Bay         1       04/12/2007        6.2          36.9             1          Open
Blackman Bay         1       23/05/2007       21.8          35.5            50          Open
Blackman Bay         2       06/03/2007       61.8          35.8            0.9         Open
Blackman Bay         2       16/08/2007       42.8          34.1            0.9         Open
Blackman Bay         2       08/10/2007        6.8          34.9            0.9         Open
Blackman Bay         2       19/10/2007        8.6          35.3            0.9         Open
Blackman Bay         2       04/12/2007        6.2          36.3            0.9         Open
Blackman Bay         2       23/05/2007       21.8          35.5            52          Open
Blackman Bay         4       06/03/2007       61.8          35.5            0.9         Open
Blackman Bay         4       23/05/2007       21.8          35.2            0.9         Open
Blackman Bay         4       16/08/2007       42.8          35.1            0.9         Open
Blackman Bay         4       08/10/2007        6.8          35.2            0.9         Open
Blackman Bay         4       19/10/2007        8.6          35.2            0.9         Open
Blackman Bay         4       04/12/2007        6.2          35.3             3          Open
Blackman Bay         7       06/03/2007       61.8          36.1            0.9         Open
Blackman Bay         7       23/05/2007       21.8          35.3            0.9         Open
Blackman Bay         7       08/10/2007        6.8          34.8            0.9         Open
Blackman Bay         7       19/10/2007        8.6          34.1            0.9         Open
Blackman Bay         7       16/08/2007       42.8          33.4             1          Open
Blackman Bay         7       04/12/2007        6.2          36.3             1          Open
Blackman Bay         8       06/03/2007       61.8          35.6            0.9         Open
Blackman Bay         8       23/05/2007       21.8          35.3            0.9         Open
Blackman Bay         8       16/08/2007       42.8           34             0.9         Open
Blackman Bay         8       08/10/2007        6.8          34.9            0.9         Open
Blackman Bay         8       19/10/2007        8.6           35             0.9         Open
Blackman Bay         8       04/12/2007        6.2          35.5             6          Open
Blackman Bay        12       06/03/2007       61.8          36.5            0.9         Open
Blackman Bay        12       23/05/2007       21.8          35.6            0.9         Open
Blackman Bay        12       16/08/2007       42.8          33.5            0.9         Open
Blackman Bay        12       08/10/2007        6.8          34.9            0.9         Open
Blackman Bay        12       19/10/2007        8.6           35             0.9         Open
Blackman Bay        12       04/12/2007        6.2          36.5            0.9         Open
Blackman Bay        16       06/03/2007       61.8          36.2            0.9         Open
Blackman Bay        16       23/05/2007       21.8          35.5            0.9         Open
Blackman Bay        16       16/08/2007       42.8          34.7            0.9         Open
Blackman Bay        16       08/10/2007        6.8          35.4            0.9         Open
Blackman Bay        16       19/10/2007        8.6          35.3            0.9         Open
Blackman Bay        16       04/12/2007        6.2          35.6            0.9         Open
Blackman Bay         18      23/05/2007         21.8      35.6             0.9        Open
Blackman Bay         18      08/10/2007          6.8      34.9             0.9        Open
Blackman Bay         18      04/12/2007          6.2      37.2             0.9        Open
Blackman Bay         18      06/03/2007         61.8      36.6              1         Open
Blackman Bay         18      19/10/2007          8.6       35               1         Open
Blackman Bay         19      06/03/2007         61.8      35.6             0.9        Open
Blackman Bay         19      23/05/2007         21.8      35.4             0.9        Open
Blackman Bay         19      16/08/2007         42.8      34.1             0.9        Open
Blackman Bay         19      08/10/2007          6.8       35              0.9        Open
Blackman Bay         19      19/10/2007          8.6      34.9             0.9        Open
Blackman Bay         19      04/12/2007          6.2      35.4             0.9        Open
Blackman Bay         20      06/03/2007         61.8      35.6             0.9        Open
Blackman Bay         20      23/05/2007         21.8      35.3             0.9        Open
Blackman Bay         20      16/08/2007         42.8                       0.9        Open
Blackman Bay         20      08/10/2007          6.8      35.4             0.9        Open
Blackman Bay         20      19/10/2007          8.6      35.4             0.9        Open
Blackman Bay         20      04/12/2007          6.2      35.4             0.9        Open
Blackman Bay         21      23/05/2007         21.8      35.6             0.9        Open
Blackman Bay         21      08/10/2007          6.8       35              0.9        Open
Blackman Bay         21      19/10/2007          8.6      35.2             0.9        Open
Blackman Bay         21      04/12/2007          6.2      37.1             0.9        Open
Blackman Bay         21      06/03/2007         61.8      36.5              1         Open




SUMMARY TABLES-
(a) Samples collected during year under all conditions.
      Site No.      Count             Minimum                    Maximum
                               Thermotolerant coliforms    Thermotolerant coliforms
                                     (per 100ml)                (per 100ml)
                                    Blackman Bay
         1            5                  0.9                         50
         2            6                  0.9                         52
         4            6                  0.9                          3
         7            6                  0.9                          1
         8            4                  0.9                         6.0
        16            6                  0.9                         0.9
        19            6                  0.9                         0.9
        20            6                  0.9                         0.9
                                 Blackmans Bay East
        12            6                   0.9                        0.9
        18            5                   0.9                        1.0
        21            5                   0.9                        0.9



(b)       Meat bacteriological tests
During 2007 no meats were analysed by TSQAP for E. coli levels from either Blackman
Bay zone.
(c)    Water sample site re-analysis
Most of the water samples collected in Blackman Bay showed excellent water quality,
even after 61.8mm of rain in 7 days at Nugent. However sites 1 and 2 did show elevated
thermo-tolerant coliforms on one occasion (23/5/07) when the 7 day rainfall was
21.8mm and salinity was normal at 35.5. This is an unusual result for these sites as they
are classified as fully approved. It should be noted that no harvesting activity was
occurring at this time. The lease situated between sites 1 and 2 has been unproductive
for some time.
A statistical analysis of the last 30 samples at each site going back to 2002 (all samples
at sites 18 and 21) show that Blackman Bay still complies with the fully approved
classification (median thermo-tolerant coliform <14/100ml and no more than 10% of
samples above 21 thermo-tolerant coliforms/100ml). It should be noted that the
sampling strategy has targeted rainfall events, and on 5 occasions the 7 day rainfall at
Nugent was greater than 90mm.
Blackmans Bay East still complies with the Approved Conditional classification, where
the condition for remaining open is 7 day rainfall <70mm in one week (see table below).
Statistical Summary of last 30 samples collected from Blackman Bay, where
available.
Site     Count       Minimum        Maximum         Median        % samples      % samples
No.                   Thermo-        Thermo-       Thermo-        >21 thermo-    >21 thermo-
                      tolerant       tolerant       tolerant        tolerant        tolerant
                     coliforms      coliforms    coliforms (per    coliforms       coliforms
                    (per 100ml)    (per 100ml)       100ml)       (per 100ml)     (/100ml) in
                                                                                 open status
                                       Blackmans Bay
  1          30         0.9             50           0.9              6.7            NA
  2          30         0.9            143           0.9              10             NA
  4          30         0.9             43           0.9              3.3            NA
  7          30         0.9            301           0.9              6.7            NA
  8          30         0.9            120           0.9              6.7            NA
 16          30         0.9             61           0.9              3.3            NA
 19          29         0.9            130           0.9              3.3            NA
 20          30         0.9              7           0.9               0             NA
                                    Blackmans Bay East
 12          30         0.9           3001           0.9              6.7              0
 18          28         0.9           1001           0.9             10.7              0
 21          24         0.9           1001           0.9             16.7              0
HEAVY METALS AND OTHER CHEMICALS
Heavy metal levels were last analysed in oysters from Blackman Bay in November
2005. The results were presented in the triennial review completed for the area in early
2007 but are reproduced here again for completeness of information. There were no
levels of heavy metals of any concern. The results are extremely similar to those
obtained from shellfish sampled from Dunalley Bay in 2005 which is not surprising as
the two areas are influenced by the same water body.


                                          FSANZ
                             FSANZ                     FSANZ
                                           G.E.L.               Blackman Bay
                            Max. level               G.E.L. 90%
                                          median                  Lease 127
                             (mg/kg)                  (mg/kg)
                                          (mg/kg)
Shellfish                                                         Pacific oysters

Date of sampling
                                                                    18/10//2005
Average Size (mm)
                                                                      85-100
Total Arsenic (mg/kg)
                                                                        4.0
Inorganic Arsenic
                                 1
(mg/kg)                                                                  0.4
Cadmium (mg/kg)                  2                                      0.09
Lead (mg/kg)                     2                                      0.09
Mercury (mg/kg)                 0.5                                     0.04
Zinc (mg/kg)                                130          290            340
Copper (mg/kg)                               5            30             11
Cobalt                                                                  <0.1
Chromium                                                                0.3
Manganese                                                               1.9
Nickel                                                                     0.2
Iron                                                                       44
Results of heavy metal, herbicide and pesticide analysis on oysters sampled 18/10/2005. FSANZ
regulatory and recommended levels included (G.E.L. = generally expected level). * The arsenic level
was measured as total arsenic, and the inorganic component estimated as 10 % of this according to the
USFDA guidance document for arsenic in shellfish.



CLOSURES.
The Blackman Bay harvest area zones were not closed during 2007. There were no
rainfall events in the catchment passing the critical value of 70 mm in a 7 day period.
One event of 61mm in 7 days returned low thermo-tolerant coliform levels.
COMMENTS
The conditions for closure in Blackman Bay East remain at >70mm rainfall at
Nugent in 7 days.
Blackman Bay remains fully approved.
BIOTOXIN MONITORING
Blackman Bay is a low risk biotoxin area. As such it is specified in the Biotoxin
Management Plan 2007 to be monitored for toxic algae on a monthly basis. During
2007 the area was sampled on 7 occasions. Sampling was missed in March and April
because of a communication misunderstanding between TSQAP and the sampler and
samples were again missed in June, August and November. TSQAP has addressed the
issue of missed samples and this problem should not occur in 2008.
Algal sampling results are shown in Appendix 1. The toxic alga Gymnodinium
catenatum was found on two occasions but in low numbers requiring no management
action.
The area is to continue to be categorized as a low risk biotoxin area.


NEXT EVALUATION.
A triennial evaluation is due at the end of 2008.
Appendix 1- Algal sampling results in Blackman Bay during 2007.




AST_Report_No.                        30860      30977      32077      32610      33383      33514      34140
Date                                17/01/2007 06/02/2007 29/05/2007 30/07/2007 08/10/2007 19/10/2007 18/12/2007
Depth_m                                 0.3        0.3        0.3        0.3        0.3        0.3        0.3
Alexandrium_cf_catenella
Alexandrium_minutum
Alexandrium_cf_tamarense
Alexandrium_ostenfeldii
Dinophysis_acuminata
Dinophysis_acuta
Dinophysis_caudata
Dinphysis_fortii
Gymnodinium_catenatum                                                  300                    100
Prorocentrum_lima
Pseudo_nitzschia_seriata_group


Note: no value means not detected

				
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Description: Blackman Bay & Blackman Bay East