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