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Duch cannel
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Variation of some physiochemical parameters along a part of the Dutch cannel in North Western
Province of Sri Lanka
P.V.S.L. GunawardenaU.P.K. Epa
M. Hettiarachchi
University of Kelaniya
Introduction
Interest in shrimp farming developed in late 1970s.
Total area for prawn farming is approximately 1200 ha.
Majority of shrimp farms are in NWP.>70% of farms are in the coastal areas
around the Dutch Canal and Mundel Lagoon ecosystems.
Introduction cont…….
The Dutch Canal alone is the main source of water for approximately 850 ha of prawn ponds.
Naturally abundant in fish, crustacean, and molluscan resources.
Unfortunately, however, Dutch Canal is also the main water body receiving farm effluents.
Introduction cont…….
There is a strong potential for direct contamination of source waters.
Water exchange is very slow in some parts.
Unfortunately, much less information is available on the impact of prawn-farming on coastal water bodies.
Objectives
Evaluate levels of some physiochemical parameters along part of the Dutch channel.
Relate levels of physiochemical factors with farming practices of those areas.
Methodology
Five sampling points Karukkupane
Nalladarankattuwa Muthupanthiya Udappuwa MadurankuliyaWater samples (250ml)
- Top- Bottom
Sampling duration – Biweekly from September 2008 to September 2009
Methodology cont…….
Parameters Temperature, pH, Dissolved
Oxygen, Turbidity, Salinity
Biological Oxygen Demand, Ammonia, TDS,
Conductivity, Total Phosphorus and
Chlorophyll a
On the field
In the laboratory after preserving
Results and Discussion
Top water layers Among Physical parameters, Parameter Average Values ± Standard error
Karukkupane Nalladarankattuwa Muthupanthiya Udappuwa Madurankuliya
TDS 11207 ± 1053 ppm 11560 ± 1266 ppm 13869 ± 728 ppm 14532± 1023 ppm 12873± 1108 ppm
Conductivity 27.5 ± 8.4 mS/cm 32.5 ± 7.8 mS/cm 17.6 ± 9.2 mS/cm 17.3 ± 8.6 mS/cm 19.6± 7.3 mS/cm
Turbidity 24± 7.3 NTU 11± 7.4 NTU 31± 11.1 NTU 28 ± 7.6 NTU 45 ± 13.4 NTU
Salinity 22ppt ± 9 24 ppt ± 9 18 ppt ± 9 23ppt ± 7 19ppt ± 8
DO 4.03±0.9 mg/la
3.42±0.9 mg/la 4.79±2.0 mg/l b
5.75±2.2 mg/l b
4.60±1.1mg/lb
BOD 2.8±1.8 mg/l 2.3±1.3 mg/l 3.5±1.6 mg/l 4.5±1.7 mg/l
4.6±1.5 mg/l
Temperature 29.5±1.5 oCa 30.5±2.0 oCb 31.0±1.5 oCb 31.0±1.5 oCb 31.5±1.0 oCb
pH 7.8±0.3a 7.7±0.3a 7.9±0.4b 8.0±0.5b 8.3±0.4b
Variation of temperature in top water levels
Temperature oC
Karukkupan
e
Muth
upanth
iy
aNall
adaran
kattu
waUdap
puwa
Mad
urankuliy
a
Variation of Dissolved Oxygen in top water
DO level (mg/l)
Karukkupan
eM
uthupan
thiy
aNalladar
ankattu
wa
Udappuwa
Mad
urankuliy
a
Variation of pH in top water levels
pH
Karukkupan
eM
uthupan
thiy
aNalladar
ankattu
wa
Udappuwa
Mad
urankuliy
a
Variation of Chemical and biological factors
Parameter Karukkupane
Nalladarankattuwa
Muthupanthiya
Udappuwa madurankuliya
PO4-3 0.046 mg/l
± 0.025 0.047mg/l ± 0.021
0.018mg/l ± 0.007
0.104mg/l ± 0.261
0.030mg/l ± 0.048
[NH3] 0.120 mg/l ± 0.087
0.041 mg/l ± 0.020
0.076 mg/l ± 0.039
0.215 mg/l ± 0.096
0.226 mg/l ± 0.097
[Chlorophyll a]
24.00 mgm-3 6.63a
12.76mgm-3 5.26b
20.55mgm-3 4.21b
29.56 mgm-3 7.74a
32.85 mgm-
3 18.27c
Average value ± std. error
Variation of Chlorophyll a concentration
Chlorophyll a level (mgm-
3)
Karukkupan
eM
uthupan
thiy
aNall
adaran
kattu
wa
Udappuwa
Mad
urankuliy
a
Bottom water layer
Udappuwa and Madurankuliya resulted significantly higher levels of
Turbidity ( 21.8 ± 9.3 NTU and 35.3± 7.6 NTU )
pH ( 9.3 ± 1.4 and 10.2 ± 1.2)NH3+( 0.22 ± 0.008 mg /l and 0.38 ±
0.006 mg/l)PO4-3 ( 0.048 ± 0.005 mg/l and 0.106
± 0.004 mg/l)BOD ( 2.53 ± 0.60 and 3.41 ± 0.8
mg/l )
Variation of bottom turbidity places
Karukkupan
e Muth
upanth
iy
aNalladar
ankattu
wa
Udappuwa
Mad
urankuliy
a
Turbidity (NTU)
Variation of bottom pH in different palaces
Karukkupan
e Muth
upanth
iy
aNall
adaran
kattu
wa
Udappuwa
Mad
urankuliy
a
pH
Variation of NH3
Karukkupan
eM
uthupan
thiy
aNall
adaran
kattu
wa
Udappuwa
Mad
urankuliy
a
NH3 Concentration (mg /l)
Variation of bottom BOD
Karukkupan
e Muth
upanth
iy
aNalladar
ankattu
wa
Udappuwa
Mad
urankuliy
a
BOD (mg/l)
Variation of bottom PO4-3
Karukkupan
e Muth
upanth
iy
aNall
adaran
kattu
wa
Udappuwa
Mad
urankuliy
a
PO4-3 concentration (mg/l)
Conclusion
Top water samples showed significantly higher levels Chlorophyll a at Karukkupane, Udappuwa and Madurankuliya.
Bottom water layers of different sites resulted significantly higher levels of
TurbiditypHNH3PO4-3 at Udappuwa and Madurankuliya
and
BOD at Muthupanthiya, Udappuwa and Madurankuliya
KarukkupaneNalladarankattuwaMuthupanthiyaUdappuwa Madurankuliya
Suggesions
Complimentary treatment systems be established to improve the quality of the receiving water, specially in the areas like Udappuwa, Madurankuliya and Muthupanthiya.
Awareness of resource user of there areas on possible impacts of elevated levels of these parameters on their activities.
Thank you
`
Karukkupane
Nalladarankattuwa
Muthupanthiya
Udappuwa
Madurankuliya
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