International Journal of Marine Science, 2017, Vol.7, No.16, 141-160
147
sediment sample carry higher bacteria than water sample in the Karnafully River (Alam, 2005). The available DO
consumed by bacterial activity and thus the presence of such materials quickly leads to a depletion of DO (Islam,
1998). Hossain et al. (1988) recorded as many as 18000 coliforms/100 mL in the Karnafully River Estuary near
sewage disposal areas which is higher than safer level (0/100 mL) for drinking water and greater than 200
cells/100 mL for bathing recommended by WHO (1984) (Table 8).
Table 7 Major taxa of macro benthos and their total number (indiv/m
2
) among Amanat Shah Bridge, Sadar Ghat, Jetty no. 15 during
post-monsoon (December-2004)
Major taxa
Amanat Shah Bridge
Sadar Ghat
Jetty no. 15
Polychaeta
1083.333
1166.667
500.000
Oligochaeta
625.00
750.000
583.3333
Gastropoda
83.3333
0.00000
208.3333
Bivalvia
166.6667
83.3333
0.000000
Crab larvae
41.6666
0.00000
0.000000
Amphipoda
83.3333
41.6666
41.6666
Urchin
0.00000
41.6666
0.00000
Megalopa
41.6666
41.6666
0.00000
Nematoda
83.3333
83.3333
83.3333
Isopoda
41.6666
0.00000
41.6666
Insecta
83.3333
125.000
0.00000
Unidentified
375.00
208.333
291.6667
Total
2708.33
2541.667
1750.00
Note: Source: Chowdhury (2005)
Table 8 Seasonal variations of different group of organisms/m
2
at polluted and unpolluted area of the Karnafully River Estuary
Months
& Years
Oligochaeta (Ind/m
2
) Polychaeta (Ind/m
2
) Mollusca (Ind/m
2
)
Miscellaneous group (Crab
larvae, Mysids, Amphipod,
Shrimp larvae, Dipteran
larvae) (Ind/m
2
)
Total organisms
(Ind/m
2
)
Polluted Unpolluted Polluted Unpolluted Polluted Unpolluted Polluted Unpolluted
Polluted Unpolluted
April’82 67203
83
1042
63
125
104
-
21
68375
271
May’82 7667
83
333
63
313
63
42
-
8355
209
June’82 2167
63
792
42
417
73
62
73
3438
251
July’82 77488
292
21
-
-
146
-
21
77509
459
Aug’82 22417
42
542
105
167
83
42
21
23168
251
Sept’82 83
-
-
-
-
-
-
-
83
-
Oct’82
1500
21
250
73
-
-
-
104
1750
198
Nov’82 646
-
146
73
-
83
-
-
792
136
Dec’82 21
-
188
-
-
-
42
-
251
-
Jan’82
417
-
833
-
-
-
-
-
1250
-
Feb’82
988
-
563
42
-
-
-
-
1521
42
Mar’82 8188
63
396
104
-
21
63
73
8667
261
Total
(Ind/m
2
)
188760 647
5106
565
1022
553
271
313
195159
Bacteriological study showed that coliform bacteria and faecal
streptococci
occurred in greater frequency in the
polluted area of the Karnafully River rather than pristine area. Polluted stations (Sadarghat and Majhirghat) were
dominant in respect of quantitative distribution of Oligochaetes and Polychaetes and occasionally Molluscs
(Hossain, 1983) (Table 9).
