Geeta Chawla

Pathomorphological changes in gills of fish fingerlings (Cirrhina mrigala) by linear alkyl benzene sulfonate

Fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of LC50) concentration to detergents (linear alkyl benzene sulfonate) showed marked behavioral changes and distorted appearance of primary and secondary lamellae along with damage to gill epithelium under scanning electron microscopy at various magnifications. Mucosal cells of gills were found to secrete mucus showing primary reactions for membrane damage leading to dysfunction in respiration and osmoregulation.

Biochemical studies on the toxicity of linear alkylbenzene sulphonate to Scenedesmus quadricauda in culture

Abstract The biochemical mechanisms involved in the response of the fresh water alga Scenedesmus quadricauda in experimental culture to linear alkylbenzene sulphonate (LAS), the active component of synthetic detergents, and a major water pollutants are studied. At 0.02% LAS (w/v) a growth promoting and at 0.1% a toxic effect was manifested. Transmission electron microscopy showed altered functional organization, especially in chloroplasts. Impairment in photosynthesis as studied by 14 CO 2 assimilation and oxygen evolution on illumination was also evident at the toxic level. Incorporation of 14 C-glycine from the medium to chlorophylls, as tested after thin layer chromatography and Sephadex LH 20 gel filtration, suggested chlorophyll synthesis to be a target of toxicity. Alkaline fructose-diphosphatase activity was also adversely affected. Dark respiration and heterotrophic fixation of 14 CO 2 were also inhibited by higher levels of LAS. The algae were found to elicit uptake of LAS from the medium, partly degrading it and using it for growth, and partly accumulating it leading to toxicity. The biochemical basis of phycotoxicity is explained and its significance to ecotoxicology of water pollutants discussed.

Effect of pH and temperature on the uptake of cadmium by Lemna minor L

Many aquatic macrophytes have the capacity to take up toxic heavy metals from polluted water and accumulate them. Cut leaves and intact plants have been suggested for clearing polluted water bodies of heavy metals. However, uptake of metal ion from water is dependent on concentration, pH, temperature, presence of other substances and functional and morphological status of the biotic species. In an attempt to understand any correlation between metal bioconcentration, pH and temperature, the optimal conditions for the removal of cadmium ions by duckweed, Lemna minor (L.) were studied.

Effect of linear alkyl benzene sulfonate in skin of fish fingerlings (Cirrhina mrigala): observations with scanning electron microscope.

Pathomorphological changes in the skin was noticed under the scanning electron microscope in fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of the LC50) concentration to linear alkyl benzene sulfonate. The epithelial cells present in the epidermis of the skin were found to secrete more mucus with linear alkyl benzene sulfonate (LAS) than did controls. The presence or deposition of mucus on the surface of skin indicated likely molecular interaction between constituents of mucus and LAS.

Effect of linear alkylbenzene sulfonate on Scenedesmus quardicauda in culture

Abstract Synthetic detergents are among the most prevalent of water pollutants leading to ecological disturbances. Therefore, their potential ecotoxicological impact was studied using a laboratory model system. The effect of different concentrations of linear alkylbenzene sulfonate (LAS), a major component of synthetic detergent, on experimental cultures of the fresh water alga Scenedesmus quardicauda has been studied. The threshold level for LAS was found to be 0.05%, above that level marked toxicity was evident and growth and survival of exposed cultures were adversely affected. There was also a decrease in nutrient uptake and in protein and DNA syntheses. Pathomorphological alterations were also evident from scanning electron microscopic observations. The significance of the above data in relation to aquatic toxicity and ecotoxicological impact of synthetic detergents is discussed.

Combined effects of cadmium and linear alkyl benzene sulfonate on Lemna minor L

The effects of 0.1 ppm cadmium and 0.005% linear alkyl benzene sulfonates (LAS) on the uptake and metabolic incorporation of 14C glycine by Lemna minor L., after 2, 24 and 48 h were studied for antagonistic/synergistic effects. Combined exposure was found to decrease the 14C incorporation into proteins, DNA, RNA and phospholipids, to a greater extent than individual exposure. The presence of LAS increased the uptake of 109Cd in the plants.

Toxicity of linear alkyl benzene sulphonate on some aquatic plants

The effect of different concentrations of linear alkyl benzene sulphonate under laboratory conditions on Salvinia molesta Mitchell, Hydrilla verticillata (L.f.) Royle, Ceratophyllum demursum L., Lemna minor L., Spirodella polyrhiza (L.) Schleid, and Pistia stratiotes L. was studied. A dose dependent effect on protein and chlorophyll a and b contents leading to substantial changes were noticed in the ultrastructural features as evident from scanning electron microscopy.

Ultrastructural and biochemical effects of cadmium on the aquatic fern Marsilea minuta Linn

The uptake of cadmium by cultured vegetative clones of the aquatic fern Marsilea minuta was studied in a static experimental bioassay system as functions of dose and period of exposure. The pathomorphological manifestations of Cd toxicity, as studied by transmission electron microscope, indicated damage to chloroplasts and tonoplasts as well as electron opaque granular deposits. Preliminary evidence based on molecular sieving chromatography showed the formation of two cadmium-binding proteins of 78 and 33 kDa in the leaf tissue under cadmium stress.

Phycotoxicity of linear alkylbenzene sulfonate

Dose- and time-dependent effects of linear alkylbenzene sulfonate, a major component of synthetic detergent, to the blue-green alga Nostoc muscorum, were studied under laboratory conditions. Toxicity was evident, at doses above 0.001%, from the decrease in biomass, heterocyst number, and protein content and pathomorphological alterations.

Free radical changes in Scenedesmus quadricauda under photoperiodic and xenobiotic stress

Abstract The activity of superoxide dismutase and the formation of products reactive with thiobarbituric acid from lipid peroxidation by Scenedesmus quadricauda cultures subjected to different photoperiods and exposed to linear alkylbenzene sulphonate, a common water pollutant, showed significant changes. After 16 h of illumination the dissolved oxygen content of the medium was at a maximum and superoxide dismutase and lipid peroxidation were enhanced, as compared with shorter periods of illumination. The presence of the detergent caused a significant difference in the physiological regulation of oxygen stress and free radical mediated processes.