Evaluation of the Comparative Toxicity of Thiotox,Dichlorvos and Carbofuran to Two Fresh Water Teleosts Ophiocephalus punctatus and Mystus Vittatus

The present study was undertaken to evaluate the comparative toxicity of Thiotox (Endosulfan) (an organochlorine), Dichlorvos (DDVP) (an organophosphorus) and Carbofuran (a carbamate) so as to determine the TL 50 values, acute toxicity ranges, relative toxicities, relative susceptibility, safe concentrations, regression equations, heterogeneity factor and 95% confidence limits for the period of 24, 48, 72 and 96 h, taking two fresh water teleosts, Mystus vittatus and Ophiocephalus punctatus as test animals. From the relative toxicity of these pesticides it is evident that thiotox was the most toxic and dichlorvos the least toxic one, while the toxicity of carbofuran was in between these two extremes for both the fishes. On the basis of relative susceptibility, Mystus vittatus was found to be more susceptible than Ophiocephalus punctatus for thiotox, dichlorvos and carbofuran, respectively. The safe concentrations were computed for all the three pesticides taking different application factors, so as to avoid the long term water pollution by these pesticides.     

Acute Toxicity of Some Industrial Effluents in Relation to the Fish Size of Cyprinus carpio (HAM.) and Channa punctatus (BLOCH)

The fish Cyprinus carpio (HAM.) and Channa punctatus (BL.) of the size ranging between 6.0 ± 1.2 cm and 28.0 ± 1.6 cm were exposed to different concentrations of industrial effluents from M/s Punjab Tannery Ltd. (Jalandhar), M/s Spinning Mill Ltd. (Hoshiarpur) and M/s Food Specialist Ltd. (Moga) for evaluating the influence of fish size on the acute toxicity of these effluents. Results indicate that the relative toxicity of the effluents decreased with the increase in fish size from 6.0 ± 1.2 cm to 20.6 ± 1.5 cm. However, for specimens of the size of 28.0 ± 1.6 cm and more, the toxicity of the effluents increased with an increase in fish size. On the basis of the relative toxicity to fish, effluent from Punjab Tannery was found highly toxic and from Food Specialist Industry, the least toxic.     

Biochemical Study of the Gonads of Mystus vittatus (Bl.) Exposed to the Acute Toxic Dose of NPK During the Spawning Season: Protein and Amino Acids

The freshwater catfish, Mystus vittatus, were exposed to the LC₅₀, 96 h dose (i.e. 550 ppm.) of the agro-fertilizer NPK for 96 h, during the spawning period (March–June). Their gonads were biochemically analysed for the total protein content and the free amino acids. The protein content of the gonads of the stressed fish was found lowered. The fish also showed disappearence of certain amino acids from their gonads.     

Toxicity of Copper and Cadmium to Heteropneustes fossilis (BLOCH)

Static bioassay tests were conducted to determine the acute toxic effects of copper, cadmium and their mixtures on Heteropneustes fossilis in two different seasons. Median lethal concentrations (24, 48, 72 and 96 h LC50) revealed that copper is more toxic to fish even at very low concentrations in comparison to cadmium, tested separately or in combination with cadmium. The data indicate that the level of tolerance of the fish to metallic ions tested was temperature specific. Generally, fishes were found to be more susceptible to metallic ions at higher temperatures as revealed by the threshold concentration, MATC and LC50 values. The behavioural changes of the test fishes were also observed in reference to different concentrations of the metallic ions and temperatures.     

Studies on the Effect of DDT on the Regeneration of Cutaneous Wounds in Mystus (mystus) vittatus Bl. (Bagridae)

The effects of DDT on the regeneration of cutaneous wounds has been studied in Mystus (mystus) vittatus. The fishes were locally collected, they were inflicted incised wounds surgically and kept in 0.01 and 0.15 ppm concentrations of DDT. The regenerating skin at different stages of development ranging from 15 min to 25 d after the injury was studied through microtomy sections. The following toxic effects were studied:

• A small amount of DDT accumulated in the subcutis at the 25 days stage,
• the regeneration of wounds under DDT stress has been slower, delayed or irregular,
• the secretion of fibrinous exudate has been copious,
• epithelization and fibroblastic activities have been slower,
• the higher concentration of 0.15 ppm of DDT produced more toxic effects than the lower concentration of 0.01 ppm,
• the earlier stages of wound healing up to 3 d have been more adversely affected than later stages.

     

Toxicity of distillery wastes to Puntius sophore (HAM.) and Mystus Vittatus (BLOCH) (Pisces,Cyprinidae, Bagridae) Part 3: Bioassay studies and TLm determination

The toxicity of the distillation wastes with low acidity, high turbidity and high organic load to the two fish species is tested by a laboratory test. The threshold value of toxicity is found at a 4 or 7 per cent dilution of wastewater. The statistical analysis of the survival rates has shown that the survival rates are significantly dependent on concentration and the time of exposure, for Puntius sophore also on temperature within the range of 20…34°C. Mystus vittatus proves to be the significantly more resistant species. The maximum permissible concentration of waste in the water ist calculated, too.     

Studies on the Acute Toxicity of Zinc to a Freshwater Teleost: Channa punctatus (Bloch)

Static bioassay tests were carried out on Channa punctatus Bloch in the laboratory after renewal of concentrations every 24 h. The LC₅₀ values and 95 per cent confidence limits were 45.21 (39.62 … 51.11) ppm at 12 h and 29.8 (27.49 … 31.95) ppm of Zn at 96 h of exposure. The actual dissolution values of zinc were also determined in test solutions using an atomic absorption spectrophotometer. Behavioural changes were the higher rate of opercular movements, surfacing, loss of equilibrium and haemorrhage near mouth and caudal fin. The LT₅₀ values indicate that survival was increased with decreasing Zn concentration. The histopathological changes observed due to Zn toxicity in the gills have been discussed in relation to fish mortality.     

Acute toxicity of cadmium to Channa punctatus (BLOCH)

Effects of acute cadmium poisoning on survival, its residual values and histopathology in certain organs of a freshwater airbreathing fish, Channa punctatus (BLOCH ) were investigated. The threshold concentration, MATC and LC₅₀ values obtained from 96 h static bioassay, revealed that Channa is more susceptible to cadmium ions at higher temperature. The atomic absorption spectrophotometric determination of cadmium residues differed significantly in organs of specimens having survived and died after 96 h of exposure. The gill accumulate the highest amount of cadmium, the liver accumulated a slightly smaller amount than the gill, while the kidney accumulated the least. The histopathological lesions subjected to sublethal (5.2 mg/l Cd) and lethal (8.4 mg/l Cd) concentrations of cadmium were: detachment and rupture of lamellar epithelium, collapse of pillar cells and hypertrophy in mucus producing gland cells in the gill; vacuolization and coagulative necrosis in hepatic cells of the liver; and expansion, necrosis and accumulation of cellular debris in renal tubules of the kidney. The probable causes for death of fish due to cadmium ions have been discussed.     

Tolerance measurement and histopathological observations on the gills of Mystus M. vittatus under the toxic stress of the fertilizer NPK

The tolerance level of the fertilizer NPK for the freshwater siluroid Mystus M. vittatus (BL .) and histopathological changes in the gill of this fish against two concentrations of NPK were investigated. It was found that at 400 ppm (24 h) mortality in the fish started, and at 700 ppm (96 h) all the fish died. Hence the concentration of NPK at 400 ppm was taken as an experimental concentration for this fish. Curling towards the upperside in the secondary lamellae resulting in the joining with each other and profuse mucus secretion and subsequent death of 40% of the fish (96 h) were observed. At 700 ppm (96 h) NPK, which is far higher than the highest tolerance limit of the fish, all the fish died. Profuse mucus secretion, formation of subepithelial spaces, sloughing of epithelial layer, leaving only the rows of pilaster cells, resulting in the death of the fish, were observed. The mortality of the fish was due to asphyxiation and damage in the gill tissues resulting in the alteration in the respiratory and osmoregulatory metabolism.     

Lethal Effects of Zinc and Nickel on Freshwater Teleosts

Static bioassays were conducted at 20.5£C and the hardness of 260 ppm as CaCO₃ with zinc sulphate and nickel sulphate using Puntius sophore, Rasbora daniconius neilgeriensis, Channa punctatus and Lebistes reticulates. The 96 h LC50 values for all four fish species ranged from 29.88 to 54.95 £ of zinc and 13.57 to 48.83 £ of nickel. Channa punctatus were consistently more sensitive to zinc, while Puntius sophore were to nickel. The behavioural changes, such as loss of equilibrium and shoaling nature, swimming with their bellies upwards and irregular opercular movement were noted.     

Biochemical study of the gonads of Mystus vittatus exposed to the fertilizer NPK during the spawning season. Part 1: Carbohydrates

The gonads of spawning Mystus vittatus exposed for 96 h to the LC₅₀-96 h dose (i.e. 550 ppm) of NPK, the agricultural fertilizer, were biochemically analysed for their carbohydrate content. The glucose and glycogen contents of the spawning fish were found to be lowered significantly, and the total carbohydrate and lactic acid contents altered insignificantly, under the pollutional stress. The stressed fish also exhibited the presence of some additional free sugars within their gonads.     

Effect of lethal concentrations of copper on Mystus bleekeri (day)

In the batch test with daily exchange of medium the effect of copper ions at 2.4 mmol/l (Ca²⁺ + Mg²⁺) over 10 d of exposure is investigated. The LT₅₀ values and 95% confidence limits at 3.7, 2.1 and 1.0 ppm of Cu were 26.7 (23.6… 29.9), 47.5 (39.6… 57.0) and 101.5 (78.5… 130.7) h, respectively. The LC₅₀ values of copper in ppm were 4.05 (24 h), 1.69 (48 h), 0.829 (9.96 and 0.776 (240 h).     

Effects of Copper Sulphate on the Free Amino Acids of Channa punctatus (BLOCH).

The free amino acids of the liver and muscle of C. punctatus exposed to 1 ppm of copper sulphate solution up to 84 days were investigated. Few amino acids, notably cystine and tryptophan, disappeared and few new amino acids appeared. These changes in the free amino acids may be due to toxic effects of copper sulphate leading to rancidity in the fish.     

Some Haematological Effects of Crude Oil on Freshwater Catfish,Heteropneustes fossilis (BLOCH)

The exposure of catfish, Heteropneustes fossilis to different concentrations (200, 500, 700, 1000, 1500, 2000 ppm) of crude oil extract for a varying period (for up to 48 h in lethal extract and 360 h in sublethal one) resulted into a number of haematological changes. All the parameters taken here were found to have been increased except the haemoglobin level which fell down to 14.3 % in an acute lethal concentration (2000 ppm) after 48 h of exposure. The haematocrit value increased significantly (12 %) in 2000 ppm. The blood sugar level showed hyperglycemia in all the concentrations. The increase in ascorbic acid (28 %) was pronounced in higher concentrations. Changes occurring in different parameters seemed to be reversible as all the parameters returned to their normal levels after returning the fish to normal media, except the nuclear swelling which did not resume the normal functioning even after a prolonged treatment (1 month or more) in the recovery jar. The haematological effects shown by the crude oil resembled partly those kept in severe hypoxic conditions and partly to the fishes poisoned by heavy metals (Cu and Zn). On the basis of results obtained in this investigation, crude oil may be categorised as a complex toxic agent.     

Response of a Freshwater Ostracod (Cypris subglobosa SOWERBY) Exposed to Copper at Different pH Levels

Short-term tests of the acute toxicity of Cu²⁺ (from copper sulphate) to a freshwater ostracod, Cypris subglobosa SOWERBY were carried out at five different pH values from 5.5 to 8.5. The toxicity of copper abruptly decreased with an increase in pH of the Cu-containing medium. The 48 h EC₅₀ value of Cu increased from 0.35 ppm at pH =5.5… 5.1 ppm at pH =8.5. The per cent survival, median period of immobilization (ET₅₀), slope functions and the 95 per cent confidence limits were determined at each pH level. The direct correlation between EC₅₀ value and pH indicated that the acute toxicity of Cu decreased as the pH increased from 5.5… 8.5.     

Acute Toxicity of Mercury,Copper and Zinc to a Freshwater Pulmonate Snail,Lymnaea luteola (LAMARCK)

The short-term toxicity of mercury, copper and zinc was studied using a freshwater pulmonate snail, Lymnaea luteola (LAMARCK ). The median period of survival increases with decreasing the toxicant concentration. The 96 h LC₅₀ values and their confidence limits were 0.135 (0.112 … 0.186) ppm of Hg²⁺; 0.172 (0.118 … 0.355) ppm of Cu²⁺; and 6.13 (5.73 to 7.19) ppm of Zn²⁺. The relative potency ratio indicates that the Hg²⁺ ions were most toxic, followed by Cu²⁺ and Zn²⁺ ions.     

Accumulation and depletion of chromium in mystus vittatus (BLOCH)

Exposure against two ppm chromium from K₂Cr₂O₇ for 1 to 7 months produced increasing accumulation of chromium in the liver, kidneys, brain and bone of the freshwater fish Mystus vittatus. In gonads, the accumulation of chromium was progressive for the first 5 months (i.e., April to August), but not in the subsequent 2 months. After 4 months exposure, fish transferred to chromium–free freshwater had a significant depletion of chromium from all tissues at 1, 2 and 3 months.     

The Acute Toxicity of Plant Origin Pesticides into the Freshwater Fish Channa punctatus

Mortality to fish Channa punctatus caused by the latices of four species of terrestrial plants belonging to family Euphorbiaceae and Apocynaceae have been reported. It was found that extremely dilute aqueous solutions of the latex were effective in killing the fishes. The ranking of toxicity of four plants was Nerium indicum > Euphorbia royleana > Thevetia peruviana > Jatropha gossypifolia. It has been suggested that these plant products cannot be used directly in freshwater ecosystem unless their detailed toxicity has been studied on the beneficial freshwater animals.     

Deleterious effects of Malathion on survivality and growth of the fingerlings of Channa punctatus (BLOCH.), a freshwater murrel

The LC₅₀ of Malathion for Channu punctatus is determined for 24… 96 h of exposure as 10.95… 3.22 mg/l. At exposure to 2.5 mg./l Malathion, growth–measured by increase in weight–is significantly reduced from the 19th day and reduced by 10 % till the 31st day. During the same period of time, the RNA and protein contents of the muscle is lowered by 10 and 15 %, respectively, as compared with the control. In addition to an acute toxic effect, in sublethal concentrations Malathion has also pronounced effects on growth and metabolism.     

Accumulation of DDT Residues in the Testes of Channa punctatus (Bloch): A Gas Liquid Chromatographic Analysis

Residues of DDT isomers accumulated in the testes of Channa punctatus (BLOCH) were quantitatively estimated by exposing the fish to 2.5 ppm sublethal concentration for 32 days. The study revealed a high accumulation of DDT residues in the testes. The maximum concentration of residues was noted on the 32nd day of the experiment. The DDT isomer accumulated in maximum concentrations was followed by DDE and DDD isomers. The maximum residue concentrations were 0.3221 ppm (DDT), 0.1119 ppm (DDE) and 0.0695 ppm (DDD) on the 32nd day of the experiment. The total DDT residue concentration at the final interval was 0.563 ppm.