Argonauta 7-12 2010





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Table1. Toxicity (LC50 values) of ASBME and LIBME against freshwater snail Lymnaea acuminata at different time intervals in pond.

 

Exposure periods

Effective dose (mg/L)

Limits (mg/L)

Slope value

‘t’ ratio

Hetero-geneity

LCL

UCL

Alstonia scholaris methanol extract

24h

LC50 = 55.19

47.67

70.06

2.19±0.36

6.01

0.50

48h

LC50 = 40.29

36.40

45.22

2.65±0.35

7.38

0.55

72h

LC50 = 31.48

26.64

36.00

1.96±0.34

5.71

0.14

96h

LC50 = 23.20

9.73

30.38

2.45±0.36

6.82

0.10

Lantana indica methanol extract

24h

LC50 = 41.28

34.18

57.75

1.71±0.32

5.33

0.46

48h

LC50 = 30.35

25.88

37.73

1.66±0.31

5.35

0.11

72h

LC50 = 21.38

18.15

24.48

1.96±0.31

6.32

0.38

96h

LC50 = 14.73

6.92

19.43

2.52±0.33

7.61

0.10

 

·        Hundred snails were exposed to four different concentrations of the extract.

·        Concentrations given are the final concentration (w/v) in the de-chlorinated water.

·        Mortality was determined at every 24h.

·        Regression coefficient showed that there was significant (P<0.05) negative

·        Regression between exposure time and different LC values.

·        LCL-Lower confidence limit; UCL-Upper confidence limit.

·        There was no mortality in control group.