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INTRODUCTION:
The organochlorine pesticide endosulfan (6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide) is a chlorinated hydrocarbon which is among the many most poisonous pesticides for aquatic life, particularly fish, and due to this fact has been registered as a precedence pollutant by the US Environmental Safety Company. Notably in creating nations, endosulfan is normally use for pest management in jute, cotton, sugar cane and greens. As a result of agricultural actions, endosulfan has repeatedly been reported in floor waters and soil of creating and established nations. It’s extra poisonous to the fish mannequin of the current examine, because the fish is a mud dweller and stays in touch to the soil for longer time. Endosulfan is reasonably persistent within the soil atmosphere with a reported common subject half-life of fifty days. Acute toxicity of endosulfan to fish was reported beforehand.
Earlier histopathological research on fishes uncovered to pollution revealed that fish organs are environment friendly indicators of water high quality. The gills are necessary organs in fish to carry out respiration, osmoregulation, acid base steadiness and nitrogenous waste excretion. Fish gills are additionally susceptible to pollution in water due to their giant floor space and exterior location. For that reason, fish gills are thought-about to be most acceptable indicators of water air pollution ranges. Many investigators have reported the histopathological adjustments within the gills of various fish species uncovered to varied pesticides. Nonetheless, there was little info on the histopathological influence of endosulfan on fish gills.. Due to this fact, it was determined to find out the histopathological results of gills in a catfish, Clarias batrachus Linn. uncovered chronically to endosulfan within the current analysis.
MATERIALS AND METHODS:
Grownup fish with a median physique weight of 0.2 ± 0.03 Kg and whole size of 20 ± 0.4 cm had been collected from the native market. The fish had been transferred in oxygenated containers to the laboratory. They had been acclimated in glass aquaria at a continuing temperature (24±l°C) and pH 7.5 ± 0.3 for 7 days previous to the experiment. Aged faucet water was used for acclimation in addition to for making ready check options. Water was constantly aerated. Fish had been fed twice day by day with Tubifex tubifex. Technical grade endosulfan (Thiodan®, 33.70% endosulfan) was offered by Hoechst Co. India Ltd.
The fish had been divided into two teams and positioned in separate glass aquaria. Ten fishes had been used for every group. Group I used to be uncovered to industrial formulations of endosulfan. The nominal concentrations examined had been 0.5 µg/L for endosulfan, being the l/twelfth fractions of the 96h LC50 worth. Group II was maintained in pesticide-free water to function management. Half the quantity of check water was renewed each 24 hour. The typical values for the water high quality knowledge had been, temperature 24±l°C, pH 7.5 ± 0.3, dissolved oxygen 7.2 mg/L and whole hardness 168 mg/L as CaCO3.
Clarias batrachus uncovered to endosulfan didn’t present any alteration in behavioural patterns and feeding exercise. Likewise, development was not retarded following publicity to endosulfan, and other than mucus secretion no macroscopically overt indicators of pathology might be discerned throughout dissection.
Each the experimental and management fish had been sacrificed each 15 days for 30 days. Instantly after decapitation the gills had been eliminated and dropped into aqueous Bouin’s fluid. After fixation for twenty-four hours, tissues had been dehydrated by a graded collection of ethanol, cleared in xylene and infiltrated within the paraffin. 4-6 µm thick sections had been minimize on microtome and stained in Hematoxylin-Eosin. Pathological lesions had been examined below optical microscope.
RESULTS AND DISCUSSION:
Endosulfan is a chlorinated hydrocarbon insecticide and acaricide of the cyclodiene subgroup which acts as a poison to all kinds of bugs and mites on contact. Though it might even be used as a wooden preservative, it’s used totally on all kinds of meals crops together with tea, espresso, fruits, and greens, in addition to on rice, cereals, maize, sorghum or different grains (Extoxnet, 1996). It enters the air, water, and soil throughout its manufacture and use. It’s usually sprayed onto crops and the spray might journey lengthy distances earlier than it lands on crops, soil or water. Endosulfan on crops normally breaks down in a couple of weeks, however sticks to soil particles and will take years to fully break down. By hydrolysis, the anticipated half-lives for the alpha- and beta-endosulfan isomers had been discovered to be 3.6 days and 1.7 days, respectively. Endosulfan doesn’t dissolve simply in water. In floor water, it will get connected to soil particles floating in water or connected to soil on the backside. It could actually construct up within the our bodies of animals that reside in endosulfan-contaminated water (ATSDR, 2000). Endosulfan is reasonably persistent within the soil atmosphere with a reported common subject half-life of fifty days.
The EPA recommends that the quantity of endosulfan in rivers, lakes, and streams shouldn’t be greater than 74 elements per billion (74 ppb). The Meals and Drug Administration (FDA) permits not more than 24 elements per million (24 ppm) endosulfan on dried tea. EPA permits not more than 0.1 to 2 ppm endosulfan on different uncooked agricultural merchandise. The industrial formulations of endosulfan are 1.88 instances extra poisonous than its technical supplies.
The histopathological adjustments had been obvious in specimens uncovered to endosulfan and weren’t noticed within the management fish. After publicity, an extreme quantity of mucous noticed over the gills of reside specimens. It has been reported that the stress attributable to variations within the atmosphere and pathologic brokers induce the proliferation of mucous cells and enhance secretion.
Within the current examine, after 15 days of publicity to 0.5 µg/L endosulfan, epithelial necrosis, hypertrophy of epithelial cells, rupture of gill epithelium, haemorrhage at main lamellae, sloughing of the respiratory epithelium and hypertrophy of epithelial cells had been famous. The lifting of the epithelium, oedema, epithelial necrosis, fusion of adjoining secondary lamellae, and haemorrhage at main lamellae had been noticed within the gills of fish examined after 30 days of publicity to 0.5 µg/L.
Epithelial necrosis and rupture of gill epithelium are direct deleterious results of the irritants. The fish’s protection responses are extreme mucus secretion. Lifting of the epithelium, lamellar fusion, and club-shaped lamellae might be protecting in that it diminishes the quantity of susceptible gill floor space. The histopathological adjustments of gill may end up in hypoxia, respiratory failure issues with ionic and acid-base steadiness.
REFERENCES:
Company for Poisonous Substances and Illness Registry [ATSDR]. (2000). Toxicological Profile for endosulfan . Replace. Atlanta, GA: U.S. Division of health and Human Companies, Public health Service.
Extension Toxicology Community [EXTOXNET] (1996). Pesticide Info Profiles, information maintained and archived at Oregon State College.
