Lethal and sublethal toxicity of monocrotophos an organophosphate on the juveniles of rohu labeo rohita (ham.) under tropical conditions
By: Ramani M B.
Contributor(s): Anna Mercy T V (Guide).
Material type:
BookPublisher: Panangad Department of Fishery Biology, College of Fisheries 2000DDC classification: 639.2 Online resources: Click here to access online Dissertation note: MFSc Abstract: The seasonal utilization of paddy field for fish culture is quite common in
Kerala and West Bengal. In recent years, with the advent of high yielding varieties
of paddy, the use of pesticide has become widely prevalent. Monocrotophos is one
of the commonly used organophosphate pesticides in the paddy fields of Kerala.
The present study was designed to arrive at an experimentally determined
application factor for fixing tentative water quality criteria for monocrotophos under
tropical conditions. Juvenile Rohu Labeo rohita (46.82 ± 0.S2 mm total length,
1012.29 ± 43.12 mg wet weight) were subjected to static lethal and sublethal
bioassay. The 48 h LCso value was found to .be 104.02 mg/I at 28 ± 2°C. Juvenile
Rohu were exposed to sublethal monocrotophos concentrations (2, S, 1 a, 1S, 20
and 30 mg/l) for 32 days at 28 ± 2°C without aeration. Treatment media were
replaced every 24 hr. Fish were fed a pelleted diet at 6% wet body weight per day.
Rohu exposed to S, 1 a, 1S, 20 and 30 mg/l monocrotophos showed significantly
lower mean wet weight gain, specific growth rate (SGR) and food conversion
efficiency (FCE). But fishes of lower monocrotophos concentration of 2.0 mg/I were
not significantly different from the control. Juveniles exposed to 2, S, 1 a, 1S, 20 and
30 mg/I monocrotophos concentrations had higher moisture and ash content, and
lower protein, lipid and carbohydrate contents, as body nutrients were depleted. The
maximum acceptable toxicant concentration for juvenile Rohu was 3.16 mg/l for
S~R and FeE as end points (the most sensitive) and 24.S mg/l for percentage
survival as an end point (the least sensitive) indicating application factors of 0.03
and 0.24 respectively.
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Theses
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KAU Central Library, Thrissur Theses | 639.2 RAM/LE (Browse shelf) | Available | 171909 |
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MFSc
The seasonal utilization of paddy field for fish culture is quite common in
Kerala and West Bengal. In recent years, with the advent of high yielding varieties
of paddy, the use of pesticide has become widely prevalent. Monocrotophos is one
of the commonly used organophosphate pesticides in the paddy fields of Kerala.
The present study was designed to arrive at an experimentally determined
application factor for fixing tentative water quality criteria for monocrotophos under
tropical conditions. Juvenile Rohu Labeo rohita (46.82 ± 0.S2 mm total length,
1012.29 ± 43.12 mg wet weight) were subjected to static lethal and sublethal
bioassay. The 48 h LCso value was found to .be 104.02 mg/I at 28 ± 2°C. Juvenile
Rohu were exposed to sublethal monocrotophos concentrations (2, S, 1 a, 1S, 20
and 30 mg/l) for 32 days at 28 ± 2°C without aeration. Treatment media were
replaced every 24 hr. Fish were fed a pelleted diet at 6% wet body weight per day.
Rohu exposed to S, 1 a, 1S, 20 and 30 mg/l monocrotophos showed significantly
lower mean wet weight gain, specific growth rate (SGR) and food conversion
efficiency (FCE). But fishes of lower monocrotophos concentration of 2.0 mg/I were
not significantly different from the control. Juveniles exposed to 2, S, 1 a, 1S, 20 and
30 mg/I monocrotophos concentrations had higher moisture and ash content, and
lower protein, lipid and carbohydrate contents, as body nutrients were depleted. The
maximum acceptable toxicant concentration for juvenile Rohu was 3.16 mg/l for
S~R and FeE as end points (the most sensitive) and 24.S mg/l for percentage
survival as an end point (the least sensitive) indicating application factors of 0.03
and 0.24 respectively.
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