Changes in oxygen consumption and heart rate of the blue swimming crab, Portunus pelagicus (Linnaeus, 1766) following exposure to sublethal concentrations of copper

Weight specific oxygen consumption and heart rates were investigated in blue swimming crab, Portunus pelagicus to indicate the stress in response to increasing salinities (50, 75, 100 and 125%SW) and increasing copper concentration (0, 0.75, 1.5, 3 and 6 ppm copper) at temperature 25 degrees C. Oxygen consumption (micromol.g(-1).h(-1) was measured using closed system respirometer (Strathkelvin Instruments oxygen meter model 781). Heart rates (beat.min(-1)) were recorded using impedance techniques. It has been found that oxygen consumption and heart rate increased with decreasing salinities and increasing copper concentration. The statistic showed weight specific oxygen consumption of P. pelagicus after 96 hr exposure to 6 ppm copper in all salinities were significantly different (P < 0.05) from 0 ppm copper. Mean heart rate of P. pelagicus in 50%SW after 96 hr exposure to 6 ppm copper were significantly different (P < 0.05) from 0 ppm copper.     

Acute toxicity levels and ethological responses of Channa striatus to fertilizer industrial wastewater

The present paper deals with the toxicity of fertilizer's industrial wastewater on snake head fish Channa striatus (Bloch) previously named as Ophiocephalus sp., at different concentrations viz., 20, 40, 60, 80 and 100 percent on the behavioural changes and mortality. The exposed fish showed hyperactivity viz., jumping, operculum movement, distance travelling, somersaulting at higher concentration such as 60, 80, and 100 percent within 48 hr. At lower concentrations such as 20 and 40 percent exposed fish showed hyperactivities viz., linear movement and eye movement within 48 hr. The LC50 values of industrial wastewater were also determined viz. 89, 75, 70 and 69 percent at different duration of exposure time i.e. 48, 72, 96 and 120 hr respectively. The obtained data revealed that LC50 value decreased with increase of exposure.     

Impact of industrial effluents on the biochemical composition of fresh water fish Labeo rohita

In acute toxicity (96 hr) experiment the fingerlings of freshwater fish Labeo rohita was exposed to tannery, electroplating and textile mill effluents. The LC0 and LC50 concentrations were 15% and 20% for tannery effluents, 3% and 6% for electroplating effluents and 18% and 22% for textile mill effluents respectively. It was found that, electroplating effluent was more toxic than tannery and textile mill wastes. After acute toxicity experiments for different industrial effluents, various tissues viz. gill, liver, muscle and kidney were obtained separately from control, LC0 and LC50 groups. These tissues were used for biochemical estimations. The glycogen content in all the tissues decreased considerably upon acute toxicity of three industrial effluents except muscle in LC50 group of tannery effluent and kidney in LC50 group of textile mill effluent, when compared to control group. The total protein content decreased in all tissues in three effluents except gills in LC50 group of tannery effluent, kidney in LC50 group of electroplating effluent and kidney in LC0 group of textile mill effluent. In general total lipid content decreased in all tissues after acute exposure when compared to control group. The results obtained in the present study showed that, the industrial effluents from tannery, electroplating and textile mills caused marked depletion in biochemical composition in various tissues of the fish Labeo rohita after acute exposure.     

Toxicity of leaf extract of yellow oleander Thevetia nerifolia on Tilapia

The usefulness of leaf extract as an ideal source of 'piscicide' in shrimp farming is described Leaf toxins are safe, eco-friendly and biodegradable. The fish Tilapia, Oreochromis mossambicus was exposed to the extract and the percentage of mortality at the end of 24,48, 72 and 96 hrs was recorded. The respective toxic range of aqueous, alcohol and acetone extracts of 24 hr LC50 and 96 hr LC50 values were found to be respectively 1118.79-330.30, 699.24-129.02 and 749.95-347.23 mg dry extract/litre for Oreochromis mossambicus. The LC50 values observed in different time periods in the fish exposed to aqueous extract were relatively high compared to the values obtained in acetone and alcohol extracts. Use of leaf extract, as piscicide in aquaculture farms is considered advantageous when viewed against the backdrop of using persistent chemicals.     

Larvicidal potential of Nerium indicum and Thuja oriertelis extracts against malaria and Japanese encephalitis vector

Ethanolic and acetone extracts of Nerium indicum and Thuja orientelis have been studied against III instar larvae of Anopheles stephensi and Culex quinquefasciatus. Ethanolic extract of N. indicum is found more effective than its acetone extract against anopheline larvae with LC50 values of 185.99 and 148.05 ppm for former and 229.28 and 149.43 ppm for the later after 24 and 48 hrs of exposure. The acetone extract with LC50 values of 209.00 and 155.97 ppm is more effective in case of culicine larvae than its ethanolic extract with LC50 494.07 and 194.49 ppm after 24 and 48 hours of treatment. Ethanolic extract of T. orientelis is more effective against both the larval species with LC50 values of 13.10 and 9.02 ppm after 24 and 48 hours for anopheline and 22.74 and 16.72 ppm against culicine larvae. The acetone extract showed LC50 values of 200.87 and 127.53 ppm against anopheline and 69.03 and 51.14 ppm against culicine larvae. Thus ethanolic extract of T. orientelis is an ideal potential larvicide for both types of mosquito larvae.     

Evaluation of hemopoietic responses in Labeo rohita Hamilton following acute copper toxicity

Fish are often exposed to highly contaminated water, especially in areas where the dilution rate of waste water is low. Environmental pollutants or other stress may affect one or more of the immunological functions in fish. Effective control of toxic substances is essential for the success of fish culture, which requires fish health monitoring using biomarkers. This study evaluated the effects of heavy metal copper (Cu) at environmentally relevant concentrations on the hematopoiesis in Labeo rohita. L. rohita fingerlings were exposed to different Cu concentrations for 6, 24, 48, or 72 hr. Following exposure, percentage blast cells was found to be increased after 6 and decreased after 24, 48, and 72 hr both at sublethal and LC₅₀ concentrations, whereas percentage mature erythrocytes decreased after 6 and increased after 24, 48, and 72 hr. Erythropoietic and leukopoietic efficiencies were also affected upon exposure. Erythropoietic and leucopoietic efficiencies increased markedly after 6, 24, and 48 hr but decreased after 72 hr in sublethal-treated fish. Erythropoietic efficiency decreased significantly after 6, 24 and 48 hr but increased after 72 hr in LC₅₀-treated fish. Leukopoietic efficiency decreased significantly after 6 hr exposure and increased after 24 and 48 hr but decreased after 72 hr. Flow cytometric studies of head kidney cell cycle phase distribution revealed cell death and DNA synthesis. The percentage cell death increased in fish exposed to sublethal concentrations and rose further at LC₅₀ during the earlier hours of exposure. Synthesis of DNA was increased at sublethal concentrations but was significantly reduced at LC₅₀ dose.     

Impact of malathion on the biochemical parameters of gobiid fish, Glossogobius giuris (Ham)

There is a dearth of information regarding the changes in heart muscle metabolites induced by pesticides. In the present study, the gobiid fish, Glossogobius giuris, was exposed to sub lethal concentrations of (0.05, 0.25 and 0.5 ppm) organophosphorus pesticide, malathion for short duration (24 to 96 hr). The cardiac muscles showed maximum depletion of glycogen and cholesterol content during 72 and 96 hr after treatment with 0.5 ppm malathion. Whereas a slight fluctuation of protein and glycogen content was observed in low concentration (0.05 ppm) of malathion. The levels of protein showed a significant decrease at high concentration (0.5 ppm) when treated for longer duration (96 hr). The present study reports metabolic dysfunction in response to malathion toxicity in the fish.     

Histopathological alterations of Nile tilapia, Oreochromis niloticus in acute and subchronic alachlor exposure

Histopathological alterations in Nile tilapia, Oreochromis niloticus, aged 3 months and subjected to acute and subchronic alachlor exposure were studied by light microscopy LC50 values of alachlor for 24 hr 48 hr, 72 hr and 96 hr were 963.6, 563, 448, and 381.9 microg l(-1), respectively and the maximum acceptable toxicant concentration (MATC) was 350 microg l(-1). Fish were exposed to 381.9 (acute) and 35 microg l(-1) (sub-chronic) of alachlor for 24, 48, 72 and 96 hr and 90 days, respectively Gill lamellae and kidney tubules were the primary target organs for the acute toxic effect of alachlor while in the subchronic exposure, the toxic effect on the gills was less marked than that of the kidneys and liver Gill alterations included edema of the epithelial cell system, aneurisms with some ruptures, hypertrophy and hyperplasia of epithelial cells. The liver showed hydropic swelling of hepatocytes and vacuolation. Lipid vacuoles were observed in hepatocytes in the second and third month of subchronic exposure. The kidney showed hydropic swelling of tubular cells, lipid vacuole accumulation in many tubules, and nuclear pyknosis. The findings of this study could be used as a guideline forbiomonitoring programs on populations of Nile tilapia cultured near alachlor contaminated areas.     

Changes of hematological parameters in Prochilodus lineatus (Pisces, Prochilodontidae) exposed to sublethal concentration of cypermethrin

Freshwater fish Prochilodus lineatus were exposed to sublethal concentrations of cypermethrin (0.3 and 0.6 microg/l) for 2, 5 and 8 days. It was observed that with the increase of exposure time total erythrocyte (RBC), hemoglobin (Hb), hematocrit (Ht) and mean corpuscular hemoglobin concentration (MCHC) values decreased but mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values increased. These reports indicate that hematological parameters, may be useful as a diagnostic test for cypermethrin exposure in aquatic organisms.     

Monitoring toxicity of an azo dye methyl red and a heavy metal Cu,using plant and animal bioassays

Toxicities of an azo dye methyl red and a heavy metal copper (Cu) were quantified, using growth and mortality as end points, in four plant species and three animal species by subjecting them to short-term (4 days for animals, 10 days for plants) static bioassays. Lemna aequinoctialis Welwitch (EC₅₀: 7–16 ppm) was found to be the most sensitive species for methyl red, Ceratophyllum demersum L. (EC₅₀: 25 ppm) and Lactuca sativa L. (EC₅₀: 56 ppm) were intermediate, while Oryza sativa L. shows reduction in seedling vigor (9–27%) of <50%, being the least sensitive amongst the tested plant species. Methyl red toxicity is almost 3–5-fold higher in growing medium (pH = 5.8–6.0), even at high nutrient levels, while Cu toxicity is higher in nutrient-poor alkaline medium at alkaline pH (8.3–8.7; EC₅₀: Ceratophyllum = 104–200 ppb; Lemna = 100–170 ppb) compared to nutrient-rich acidic medium (pH = 5.4–5.7; EC₅₀: Ceratophyllum = 2600–3175 ppb; Lemna = 4350–4715 ppb). Rice tolerance (EC₅₀: 6500 ppb) was found to be higher than hydrophytes while lettuce was most tolerant to Cu. Fish sensitivity toward the test chemicals was almost parallel to Ceratophyllum and Lemna [Gambusia affinis Baird and Gerard (LC₅₀: 250 ppb for Cu) and Poecilia reticulata Peters (LC₅₀: 24 ppm for methyl red)]. Similar to the plants, dye toxicity increased markedly (LC₅₀: 7 ppm) in the acidic medium (pH = 6.0). Amongst the tested organisms, Daphnia was found to be most sensitive to methyl red (EC₅₀: 6 ppm) while its sensitivity to Cu (EC₅₀: 230 ppb) was similar to hydrophytes and fish. Initially, the combination of dye and Cu (at their sublethal concentrations) had additive effects in duckweed, while dye concentration ruled afterward. These results indicate that hydrophytes and animals are equally sensitive toward the test chemicals. Dye toxicity in hydrophytes and fish was pH dependent, while in the case of Cu, it is related to the nutrient status of the growth medium of plants.     

Formation of metallothioneins in relation to accumulation of cadmium in the common mussel Mytilus edulis

Accumulation rates of Cd have been studied in the common mussel Mytilus edulis L. under different laboratory conditions. Semi-static and through-flow experiments were carried out at Cd concentrations of 200 ppb and 50/100 ppb in the water, respectively. A linear uptake of Cd throughout the experimental periods of 36 or 124 d was found in all experiments. The accumulation rate was 3.10 ppm d^-1 at 50 ppb in the through-flow water experiment, 4.1 ppm d^-1 in starved and 6.6 ppm d^-1 in fed mussels in the semi-static experiments with 200 ppb Cd in the water. The Cd-accumulation rate in various fractions of soft parts decreased in the order: body>mantle>muscles. Elution patterns obtained from gel-filtrations showed an increasing amount of Cd-binding proteins (metallothioneins) when the body burden of Cd increased. The Cd content in the body fraction of mussels transferred to clean water for 42 d after first being exposed to Cd during 124 d decreased from 564 ppm on a dry weight basis to 417 ppm while the fraction of Cd bound to metallothioneins rose from 22 to 78% during the same period.     

Devicyprin induced gonadal impairment in a freshwater food fish, Channa punctatus (Bloch)

Synthetic pyrethroids are the recent major class of broad spectrum, photostable, organic insecticides used in agricultural, domestic and veterinary applications and now account for more than 30% of global insecticide use. Cypermethrin is metabolized and eliminated significantly more slowly by fish than by mammals or birds, which may explain this compound's high toxicity in fish compared to other organisms. The present communication deals with histoanatomical alterations in the gonads of a local fresh water food fish, Channa punctatus exposed to 0.033 ppm (96 hr LC50 X 1/10) concentration of a synthetic pyrethroid, devicyprin (cypermethrin 25%) in aquatic medium of aged tap water for 15, 30 and 45 days respectively. In testis, exposure dependent histological damage has been observed in terms of vacuolization, condensation of spermatogonic cells, distortion of tubular epithelium, shrinkage of interstitial cells and general inflammatory responses. Longest exposure of 45 days has resulted in peculiar starry-sky appearance of the testicular tissue. Gross histo-anatomy of ovarian tissue reveals epithelial lesions, inflammatory responses, stromal hemorrhage, increased interstitium and shrinkage of yolk vesicles towards periphery These findings are quite suggestive of reproductive impairments leading to delayed gonadal maturity and adversely affecting processes of sperm production and ovulation and thus, the fish production.     

Lethal levels of hypoxia for gulf coast estuarine animals

There is increasing concern about eutrophication and subsequent hypoxia problems in estuaries. The US Environmental Protection Agency has developed Water Quality Criteria (WQC) for dissolved oxygen (DO) in saltwater for Cape Cod, MA to Cape Hatteras, NC but inadequate data exists for development of such criteria for other coastal geographic areas. We performed acute tests with two species of crustaceans and seven species of estuarine fishes native to the Gulf of Mexico to complement the data base for northeastern species. Flow-through tests were conducted for either 24- or 48-h at test temperatures from 24 to 28°C and at salinities from 20 to 31.5‰. Estimated 24-h LC50 values obtained for crustaceans ranged from 1.36 mg/l for adult pink shrimp to 1.56 mg/l for 10-day-old mysids. Similarly, estimated LC50 values for fish ranged from 1.34 mg/l in one of the three tests with pinfish to 2.22 mg/l in one of the two tests with scaled sardines. The majority of mortality attributable to low DO concentrations in our experiments usually occurred within the first 4 h of exposure. LC50 values for the species tested are below the WQC recommended protective limit of 2.3 mg/l for juvenile and adult animals.     

The toxicity of ammonia,nitrite and nitrate to the fish,Catla catla (Hamilton)

The acute toxicity of unionized ammonia; nitrite and nitrate to the Indian major carp Catla catla (Hamilton) was determined using static and continuous flow through systems for 24 hours. The median lethal concentration (LC50) values for 24 h of ammonia (NH3-N), nitrite (NO2-N) and nitrate (NO3-N) were 0.045 mg/l, 120.84 mg/l and 1565.43 mg/l in static test respectively and were 0.036 mg/l, 117.43 mg/l and 1484.08 mg/l in continuous flow through test respectively.     

Impact of low dose of organophosphate, monocrotophos on the epithelial cells of gills of Cyprinus carpio communis Linn.--SEM study

The paper deals with the deleterious changes at ultrastructural level of the epithelial cells of gills of Cyprinus carpio communis Linn. upon exposure to 1/10th of LC50 of monocrotophos which is considered to be insignificant concentration from toxicological point of view. The gills of the fish are the primary corridor formolecularexchange between the internal milieu of a fish and its environment. Gills perform numerous functions such as oxygen uptake and CO2 excretion, osmoregulation, acid-basic balance, excretion of nitrogenous compounds and taste. Hazardous chemicals present in water may alter the morphology of the epithelial cells of gills of the fish, which may affect the process of diffusion of gases and ultimately the overall health of the fish. To prove this fact Cyprinus carpio communis Linn. was kept in water for 30 days having low concentration of 0.038 ppm (1\10th of LC50) of monocrotophos and an attempt was made to study the different types of degenerations produced in the epithelial cells of gills as compared to the normal epithelial cells of gills of this culturable fish using Scanning Electron Microscope (SEM) technique. The ultrastructural changes due to the toxic exposure at finer scale were thinning of microridges, upliftment of epithelial cells, development of hyperplasia, decrease in the density of mucous cells which are considered to be the first line of defence and total dystrophy of epithelial tissue. Thus, it is opined that a low concentration of monocrotophos has the potential to bring different type of degenerations at finer scale hence affecting the fish's health drastically and altering the fitness of the fish in water even having insignificant amount of this toxicant in the ambient water     

Toxicity of cypermethrin on total lipids and free fatty acids in liver,muscle, kidney and ovary of Clarias batrachus (L) and recovery response

Alterations in the levels of lipid metabolites, total lipids and free fatty acids, were studied in physiologically important tissues viz; liver, muscle, kidney and ovary of a freshwater edible fish Clarias batrachus. The fish was exposed to sublethal concentration (1/3 of LC50 value for 96?h) of a synthetic pyrethroid insecticide, cypermethrin for 1, 5 and 10 days. After 10 days of exposure, fish were released into fresh water and total lipids and free fatty acids were determined at intervals of 1, 5 and 10 days to assess fish recovery response after cessation of cypermethrin exposure. Fish showed an increased rate of lipogenesis in liver, muscle, kidney and ovary during the exposure period followed by a decrease after transfer of fish into fresh water. There was also an elevation in liver and kidney free fatty acids contents, while the muscle and ovary free fatty acid contents were reduced during exposure period. The alterations in free fatty acids were restored to near normal values after 10 days of cessation of exposure.     

Effective method for extraction of larvicidal component from leaves of Azadirachta indica and Artemisia annua Linn

Leaves of Artemisia annua linn. and Azadirachta indica were extracted in petroleum ether and hexane respectively by different methods of extraction i.e. cold extraction, reflux extraction and soxhlet extraction. The crude extract obtained was tested against third instar larvae of Anopheles stephensi. On comparison of larval mortality of crude extract obtained by these three methods, both soxhlet and reflux extraction method showed 100% mortality at 200 ppm after 48 hr in case of A. annua. However LC50 (20 ppm) value of crude extract obtained by soxhlet extraction showed better results than reflux extraction (35 ppm) method after 72 hr. In case of A. indica, crude obtained by soxhlet showed 100% mortality (after 48 hr) at 250 ppm and LC50 of 69 ppm at 72 hr. Reflux extraction does not show any appreciable mortality even at 250 ppm concentration.     

Haematotoxic effect of linear alkyl benzene sulphonate (LAS) in fish,Heteropneustes fossilis

It was observed that clotting time decreased with the increased concentrations of LAS. However, the decrease was more pronounced at LC50 for 24 h and at the end of 96 h LC50, it was very close to control values.     

Degradation and acute toxicity of Methidathion and Trichlorfon on Procambarus clarkii,in experimental conditions

Routine applications of organophosphate pesticides may adversely affect many nontarget organisms. Static toxicities in mature crayfish Procambarus clarkii were determined, in laboratory, for two organophosphate insecticides using 24, 48, 72 and 96‐h static tests. Three groups of 10 crayfish were exposed to 0.75 to 6 ppm for Trichlorfon and 0.2 to 0.9 ppm for Methidathion. The 24 to 96‐h LC50 values for Trichlorfon and Methidathion were from 5.14–0.99 ppm and 0.73–0.28 ppm respectively. Studies of degradation of Methidathion and Trichlorfon have been made using 1 ppm for Methidathion and 0.1 ppm for Trichlorfon. Both insecticides were degradated gradually until 96‐h. Results show that Methidathion is more toxic to P. clarkii in our medium and degradation of both pesticides is similar.     

Acute toxicity of copper sulphate to fresh water prawns

Fresh water prawns, Macrobrachium lamarrei and Macrobrachium dayanum (Crustacea-Decapoda) were subjected to static bioassay tests to ascertain the LC50 values of copper sulphate. The 24, 48, 72 and 96 hr LC50 values of copper sulphate for M. lamarrei were 0.38, 0.361, 0.343 and 0.300 mg/l and for M. dayanum were 1.634, 0.988, 0.532 and 0.418 mg/l respectively. Behavioral responses and LC50 values indicate that M. lamarrei were more sensitive to copper sulphate than M. dayanum.