Seasonal trend of potential toxic elements in seawater and sediments from Tuticorin coast

Potential toxic elements (PTEs) concentration was analyzed seasonally in seawater and sediment samplesfromTuticorincoast,India.TheextentofPTEs contamination in Tuticorin coast has been revealed by measuring the concentrations of iron (Fe), nickel (Ni), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) using inductively coupled plasma mass spectrophotometer (ICP-MS) seasonally. The concentration of all the PTEs in seawater samples was higher in summer and least in spring. The concentration of all the PTEs was significantly different within and among the season except for Zn and Cu. The concentration of PTEs in sediment samples was higher in winter and least in summer seasons. Exceptionally, the concentration of Cd was not significant among and within the seasons. TheconcentrationofthePTEsinseawaterandsediment samples exceeded the WHO-recommended limits. The contamination factor (CF) and geoaccumulation index (Igeo) values indicated significant contamination of PTEs in the sediment samples collected in different seasons. Variations in the concentration of PTEs could be due to changes in levels of pollution discharge over time, availability of PTEs for adsorption, as well as variations in the sampling season. The presence of a number of industries surrounding the Tuticorin coast and the release of the effluents from both industries and domestic sources are the main source of pollution at Tuticorin coast and are the prime reasons for the loss of existing diverse ecosystem

Lipid peroxidation and its control in Anguilla anguilla hepatocytes under silica-coated iron oxide nanoparticles (with or without mercury) exposure

Having multidisciplinary applications, iron oxide nanoparticles can inevitably enter aquatic system and impact inhabitants such as fish. However, the studies in this context have ignored the significance of obvious interaction of iron oxide nanoparticles with other persistent co-contaminants such as mercury (Hg) in the modulation of the toxicity and underlying mechanisms of iron oxide nanoparticles and Hg alone, and concomitant exposures. This study aimed to evaluate lipid peroxidation (LPO) and its control with glutathione (GSH) and associated enzymes (such as glutathione reductase, GR; glutathione peroxidase, GPX; glutathione sulfo-transferase, GST) in European eel (Anguilla anguilla L.) hepatocytes exposed to stressors with following schemes: (i) no silica-coated iron oxide nanoparticles functionalized with dithiocarbamate (Fe3O4@SiO2/Si DTC, hereafter called 'FeNPs'; size range 82 +/- 21 to 100 +/- 30 nm) or Hg, (ii) FeNPs (2.5 mu g L-1) alone, (iii) Hg (50 mu g L-1) alone and (iv) FeNPs + Hg concomitant condition during 0 to 72 h. The exhibition of a differential coordination between GSH regeneration (determined as GR activity) and GSH metabolism (determined as the activity of GPX and GST) was perceptible in A. anguilla hepatocytes in order to control FeNPs, Hg and FeNPs + Hg exposure condition-mediated LPO. This study revealed the significance of a fine tuning among GR, GPX and GST in keeping LPO level under control during FeNPs or Hg alone exposure, and a direct role of total GSH (TGSH) in the control of LPO level and impaired GSH metabolism under the concomitant (FeNPs + Hg) exposure. An interpretation of the fish risk to FeNPs in a multi-pollution state should equally consider the potential outcome of the interaction of FeNPs with other contaminants

Brain glutathione redox system significance for the control of silica-coated magnetite nanoparticles with or without mercury co-exposures mediated oxidative stress in European eel (Anguilla anguilla L.)

This in vitro study investigates the impact of silicacoated magnetite particles (Fe3O4@SiO2/SiDTC, hereafter called IONP; 2.5 mg L-1) and its interference with coexposure to persistent contaminant (mercury, Hg; 50 mu g L-1) during 0, 2, 4, 8, 16, 24, 48, and 72 h on European eel (Anguilla anguilla) brain and evaluates the significance of the glutathione (GSH) redox system in this context. The extent of damage (membrane lipid peroxidation, measured as thiobarbituric acid reactive substances, TBARS; protein oxidation, measured as reactive carbonyls, RCs) decreased with increasing period of exposure to IONP or IONP + Hg which was accompanied with differential responses of glutathione redox system major components (glutathione reductase, GR; glutathione peroxidase, GPX; total GSH, TGSH). The occurrence of antagonism between IONP and Hg impacts was evident at late hour (72 h), where significantly decreased TBARS and RC levels and GR and glutathione sulfotransferase (GST) activity imply the positive effect of IONP + Hg concomitant exposure against Hg-accrued negative impacts [vs. early (2 h) hour of exposure]. A period of exposuredependent IONP alone and IONP + Hg joint exposureaccrued impact was perceptible. Additionally, increased susceptibility of the GSH redox system to increased period of exposure to Hg was depicted, where insufficiency of elevated GR for the maintenance of TGSH required for membrane lipid and cellular protein protection was displayed. Overall, a finetuning among brain glutathione redox system components was revealed controlling IONP + Hg interactive impacts successfully