Acute Toxicity of Chlorantraniliprole to Freshwater Fish Channa punctatus (Bloch)

Environmental protection has attracted the attention of the wide cross-section of people all over the world which has now become a global issue amongst scientists and researchers working in this area. The aim of the present study was to determine the acute toxicity of chlorantraniliprole insecticide to the fresh water fish Channa punctatus (Bloch). Experimental fish were exposed to different concentrations of chlorantraniliprole between range 0, 1, 2,3,4,5,6,8,10,12,13,14,15,16 and 17mg/L) for 96 h in test container. The 96h LC50 value of chlorantraniliprole on the fish was found to be 14.424mg/L. The variation in the lethal concentration values is due to its dependence upon various factors viz., sensitivity to the toxicant, its concentration and duration of exposure. Further study needs the processes by which these chemicals affect physiology and pathological changes and of fish and their bio-concentration and bio-accumulation in fish tissues.


Introduction
Environmental protection has attracted the attention of the wide cross-section of people all over the world which has now become a global issue amongst scientists and researchers working in this area. Pesticidal pollution constitutes the most dangerous health hazard apart from creating adverse effects on fish production. As the fishes are economically important non-target organisms, they are quite sensitive to a wide variety of toxicants and are used as pollution indicator in the water-quality management.
Coragen 18.5% SC is a new chemical insecticide product, the active substance is chlorantraniliprole. It is applied for use in apples against codling moth apple fruit moth and free leaf living larvae. Chlorantraniliprole belongs to the Diamides Ryanodine receptor modulators. The mode of action is different to most other commercial insecticides. Identity and physical/chemical data (Product name: Coragen 18.5% SC).
Active substance: chlorantraniliprole; Formulation: Suspension concentrate; CAS number 500008-45-7,IUPAC-name:3-bromo-4'-chloro-1-(3-chloro-2-pyridyl)-2'-methyl-6'-(methylcarbamoyl)pyrazole-5-carbo xanilide).The basic mechanism of action for most pesticides is proved to be an alteration in the transfer of a signal along a nerve fiber and across the synapse from one nerve to another or from nerve to a muscle fiber. The signal is transferred across the synapse to the next nerve cell by the release of neurotransmitters such as acetylcholine (AChE) .The biochemical processes represent the most sensitive and relatively early events of pollutant damage. Thus, it is important that pollutant effects be determined and interpreted in biochemical terms, to delineate mechanisms of pollutant action, and possibly ways to mitigate adverse effects [1].Many of workers have been used the acute toxicity tests of pesticides on fish to acquire rapid estimates of the concentrations that caused direct, irreversible harm to test organism [1].
In the present study, an attempt has been made to analyze the toxicity of the chlorantraniliprole 18.5% SC (Suspension concentrate) on the freshwater fish Channa punctatus (Bloch). The result is expressed as the lethal dose (LD) in the case of terrestrial organism and as lethal concentration in the case of aquatic organisms. Since some members of population may prove to be excessively susceptible and others may prove to be very resistant to the dose or the concentration of the toxicant that affects 50% of the population under consideration is expressed as LD 50 or LC 50 values, which is statistically calculated on the basis of the observed percentage of mortality at different concentrations of the pesticides.

Materials and Methods
The freshwater fish Channa punctatus size 12-13 cm and weight 18-20 g were brought from a local waterbodies at Nandivelugu, Guntur district of Andhra Pradesh, India. The fish were acclimatized to the laboratory conditions at Advances in Zoology and Botany 1(4): 78-82, 2013 79 28±2 o C for 15 days. If in any batch, mortality exceeds 5% during acclimatization, that entire batch of fish was discarded. Insecticide was purchased from local market in Guntur of Andhra Pradesh. The water used for acclimatization and conducting experiments was clear unchlorinated ground water and the hydrographic conditions of water are shown in the Table 1. The stock solutions for the above were prepared by dissolving the chlorantraniliprole 18.5% SC in unchlorinated ground water according to Finney probit [3].

Acute Toxicity Tests
The containers of the test media are of 15 L capacity, where in each test five containers were used and each container consisted of 10 fish. The mortality rate was taken into consideration and while taking the data, dead fish was removed immediately. Pilot experiments were conducted to choose the mortality range between 10% and 100%.Basing on the pilotexperiments, the experiments were conducted to determine the toxicity indifferent concentrations (0, 1, 2, 3, 4, 5, 6,8,9,10,12,14,15,16 and 17mg/L-1for 96h with compound Anthracitic diamides, in semi-static system).
The data of each concentration was pooled up to calculate the LC50 values. The un-weighted regression method of probit analysis and SPSS v20.0 was used to calculate the LC50 values [3]. According to [4,17] the sample water is clear, colorless and odorless. The following results are in mg/L-1.

Results and Discussion
In the present investigation the test species, Channa punctatus has shown differential toxicity level with the function of period. This shows that the more is the duration period the less is the concentration required. The observed percentage of mortality of Channa punctatus for chlorantraniliprole in static tests continuous for different hours and different concentrations were shown in Table 2, 3, 4 &5. The observed LC values and 95% confidence limits in static tests were shown in Table 5.  The toxicity of a pesticide could vary from species to species. The variation is due to differential tolerance of animals to pesticide exposure [5,6], reported that toxic effect of the organophosphate pesticide phosphamidon in thiourea medium, on the freshwater fish, Sarotherodon mossambica, the LC 50 values of phosphamidon treatment such as 5.0869, 4.0598, 3.0520 2.3784 for 24, 48, 72, 96h respectively and phosphamidon in 0.03% thiourea medium such as 5.1105, 3.5650, 2.4940, 1.7330 for 24, 48, 72, 96 [7]. Reported the 96h LC 50 value of a neem biopesticide (Triology) on the grass carp fish, Ctenopharyngodon idella and was found to be 112ppm. The 96hrs LC50 values of diazinon on different fishes reported from tenth to several tens of mg/L -1 . A value of diazinon 96 hrs LC 50 was 0.8 mg/L -1 for guppy (Poecilia reticulate) and for zebra fish (Brachydanio rerio) was 8 mg/l -1 . Which were all previously described by earlier workers in crayfish [8][9][10], has estimated LC 50 value as 4 ppm for organophosphate quinolphos when exposed to Oreochromis mossambicus.
In the present study, the 96h LC 50 value of chlorantraniliprole on the fish Channa punctatus was found to be 14.424mg/L -1 . The variation in the LC values is due to its dependence upon various factors viz., sensitivity to the toxicant, its concentration and duration of exposure.

Behavioral studies
In the present study of test organism Channa punctatus showed normal behavior in control group but jerky movements, hyper secretion of mucus, opening mouth for gasping, losing scales, hyperactivity were observed experimental group. Behavioral characteristics are obviously sensitive indicators of toxicant effect. In toxic medium of chloroanthraniliprole the fish sank to bottom of the test chamber and independency in swimming. Subsequently fish moved to the corners of the test chambers, which can be viewed as avoidance behavior of the fish to the toxicant. In the toxic environment fish exhibited irregular, erratic, darting swimming movements and loss of equilibrium followed by hanging vertically in water. The above symptoms are due to inhibition of AChE activity leading to accumulation of acetylcholine in cholinergic synapses ensuing hyperstimulation. And inhibition of AChE activity is a typical characteristic of organophosphate compounds [11,12]. Increase in opercular movement was initially observed but later decreased with increase of exposure period. They slowly became lethargic, restless, and secreted excess mucus all over the body. Intermittently some of the fish were hyper excited resulting in erratic movements. An excess secretion of mucous in fish forms a non-specific response against toxicants, thereby probably reducing toxicant contact. It also forms a barrier between the body and the toxic medium, so as to minimize its irritating effect, or to scavenge it through epidermal mucus. Similar observations were made by [13, 14, and 19] following RPR-V (a novel phosphorothionate pesticide) exposure to euryhaline fish, Oreochromis mossambicus. Gulping air and swimming at the water surface (surfacing phenomenon) were observed also with mucus secretion on the body in both the lethal and sublethal exposure periods. [14], reported that fish in sub lethal concentration were found under stress but that was not fatal. Reported that the abnormal changes in the fish exposed to lethal concentration cypermethrin are time dependent. [15,20]Observed that the fish is exposed to cypermethrin, Rimon; erratic swimming, hyper and hypoactive, imbalance in posture, increase in surfacing activity, opercular movement, gradual loss in equilibrium, spreading of excess of mucus all over the surface of the body. Fishes exhibited a number of behavioral changes when they were exposed to different concentrations. The opercular movement of fishes initially increases and then gradually decreases. Decreased opercular movement probably helps in reducing absorption of pesticide through gills. Abnormal swimming and loss of balance was caused by the deficiency in nervous and muscular coordination which may be due accumulation of acetylcholine in synaptic and neuromuscular junctions observed by [16][17][18]. It is necessary, to select behavioral indices for monitoring that relates to the organisms behavior in the field in order to derive a more accurate assessment of the hazards that a contaminant may pose in natural systems.

Conclusion
From the above acute toxicity investigation, we conclude that pesticide Chlorantraniliprole were highly toxic to fish C.punctatus based on the observed LC 50 values and had a impact on behavior and respiratory responses in fish C.punctatus in lethal concentrations.