Toxicologie environnementale et analytique

The considerable contamination of the aqueous environment by organic pollutants still requires the development of effective adsorbents for removal of these compounds. The current work reports the applicability of hexagonal and cubic aluminosilica monoliths with macro-and meso-cylinder pore structures and aluminium contents with 19 ≤ Si/Al ≥ 1 as effective adsorbents for removal of organic pollutants such as aniline compounds from an aqueous solution. A simple, reproducible, and one-pot synthesis strategy was used to achieve a realistic control over a wide range of mesophase geometries, cylindrical-like pores, and relatively high surface area, yet maintains the long-range structural ordering of aluminosilica monoliths. To better understand the role of the geometry and nanoscale pore orientation of mesostructures, theoretical models have been developed. In addition, the atomic charge distribution in the interior structures was investigated to give insight about the effect of active site surfaces in the enhancement of the adsorption process. The coordination and location of aluminium sites in the frameworks play a key role in the generation of the surface acidity of aluminosilica monoliths, which enhanced the adsorption capacity of the organic pollutants. Our experimental results suggest that the acidity of the adsorbents significantly increased with increasing amounts of aluminium species in the pore framework walls. The natural surfaces of acidic active sites of monoliths strongly induced the removal and adsorption of toxic aromatic amines from wastewater. The relative adsorption affinity of the mesocylinder adsorbent for organic pollutants was decreased in the order of p-nitroaniline < o-aminophenol < p-chloroaniline < aniline. In addition, the thermodynamic studies indicated that these adsorbent monoliths with macroand meso-cylinder pore cavities show promise for the spontaneous removal of organic containments from aqueous water. Finally, we believe our adsorption model will open a new avenue in the development of simple and effective strategy for removal of pollutants and wastewater treatment.

Sagar Lake located in Sagar city, Madhya Pradesh, India has been subjected to domestic and agricultural wastewater discharges from many decades. An attempt has been made to find the seasonal quality of water in Sagar lake, in order to adopt a statistical model to examine water quality. As a result of eutrophication, quality of lake water has been continuously degraded, this result in increased content of nitrates in soil frequently which leads to undesirable changes in vegetation composition and many plant species. The physicochemical characteristics of water samples from six sampling points during three seasons were analyzed in order to determine the contaminants in lake water. Results were analyzed by using correlation analysis, multi-regression analysis and statistical modeling. The obtained results were compared with water quality standards and standard values recommended by World Health Organization (WHO), and it was found that most of the water samples were highly polluted by sewage. To minimize the complexity and dimensionality of large set of data a Systematic calculation of correlation coefficient between water quality parameters has been applied. The significant correlation has been further verified by using significance level. The results of this study clearly demonstrate the usefulness of multivariate statistical analysis in hydro chemical investigation.

Effects of exposure of common carp juveniles (Cyprinus carpio L.) to dietary copper and its recovery rate were investigated with the aim of determining the growth and physiological impact. The fish were fed elevated copper diets (1000 mgCukg-1 and 2000 mgCukg-1 as diet 2 and diet 3 respectively) and control diet (5 mgCukg-1, as diet 1) for 42days and were then fed the control diet for a further 21days. After 42days of exposure to elevated copper diets, growth performance examined showed that there was significant increase at (p<0.05) in feed intake, %body weight, weight gain and condition factor by fish fed diet 2 compared to diet 1 and diet 3. There was, however, no difference in specific growth rate, feed conversion ratio, in all treatments (p>0.05). Hepatosomatic index increased significantly in fish fed both elevated diets compared to control diet (p<0.05). Recovery period on normal diet (control) showed no significant effect of copper recovery on fed intake, weight gain, %body weight, specific growth rate and feed conversion ratio in all treatments (p>0.05), but, fish fed diet 2 showed a significant reduction in condition factor compared to other diets (p<0.05). Tissue Na+, Ca2+ K+ were disturbed throughout the experiment with sodium increasing from 257.82 ± 2.50 μmol/g to 388.14 ± 1.32μmol/g and calcium increasing from 499.54 ± 6.81 μmolg-1 to 1025.94 ± 9.16 μmolg-1 reducing gill copper from 11.63 ± 0.37 mgCukg-1to 0.00 ± 0.00mgCukg-1. Intestinal copper decreased from 14.93 ± 0.1 mgCukg-1 to 0.00 ± 0.00 mgCukg-1 as a result of sodium increasing from 130.30 ± 5.12 μmolg-1 to 438.72 ± 2.44 μmolg-1. The reduction in intestinal calcium was sodium dependent as increasing sodium decreased calcium absorption. Increased gill copper of the 1000 mgCukg-1 diet exposed fish during exposure compared to the control was due to copper induced decrease in plasma ion regulatory sodium (Na ATPase activity), which protected fish from direct toxicity effect and could also suggest another pathway other than the common Na/Cu apical channel shared between sodium and copper through which copper binds to fish gill; diet 2 fish showing significant increase at (p<0.05) in haematocrit, red blood cell, white blood cell and neutrophils, and a significant reduction in lymphocyte and mean cell hemoglobin compared to diet 1 and diet 3, (p<0.05). This increase in blood indices is indicative of stress onset to which fish fed diet 2 is subjected. Fish fed diet 3 showed significant reduction in haematocrit, red blood cell, white blood cell and increased lymphocyte (p<0.05) and became anaemic with severe skin discoloration, indicative of a worsening effect of excess dietary copper exposure on the fish. There were not significant differences in moisture content of all tissues during and after copper exposure (p<0.05), although, gills of fish fed diet 2 showed reduction in moisture compared to diet 1 and diet 3-fed fish for both exposure and recovery phases, increasing from 75.3 ± 3.20% to 79.5 ± 6.44% after recovery for 21 days. Gills of fish fed diet 3 also increased post-exposure, indicative of protection of the structural integrity of the gill to prevent hypoxia through oxygen supply from water.

Ground water is one of the major resources of the drinking water in rural area nearby Sagar city, Madhya Pradesh. In the present study groundwater quality of the selected 02 villages near by Sagar city were taken for under investigations, by collecting 75 groundwater samples from entire villages and assessed for their suitability for human consumption. Physico-chemical parameters were carried out during different months of the pre monsoon, monsoon and post monsoon seasons in Oct. 2007– July 2011. WHO water directive value is 44 mg/l for nitrate and11 mg/l nitrate in drinking water. pH values of all samples were between 5.5-8.5 limits. Conductivity of all samples was below WHO water standards. The statistical analysis of the experimentally estimated water quality parameters on water samples yielded the range of the variation, mean, standard deviation, co-efficient of variation, correlation analysis and principal component analysis.

Focusing on the influence of organic soil contents on the Phytoextraction of Cu and Zn, assisted by chelators EDTA, DTPA, EDDS, and citric acid, in Sunflower (Helianthus annuus), Chinese Cabbage (Brassica campestris), Cattail (Typha latifolia), and Reed (Phragmites communis), this study demonstrates prominent Cu and Zn uptake enhancement. Soil organic concentration has been shown to be a critical factor in metal uptake and bioavailability in plants. Organic content has less soil nutrients, and less negatively charged functional groups, such as carboxical, phenolical and hydroxyl groups. This allows adsorption of negative free metal cations, and reduces metal mobility. Regardless of various soil organic contents, this study ranks Cattail, Reed, Sunflower, and Chinese Cabbage, in descending order of propagation efficacy. The mechanism of metal is apoplastic transportation. In plant cells, the apoplast is the free diffusional space outside the plasma membrane. It contains high concentrations of carboxylic groups which act as effective cation exchangers. The negatively charged chelator complexes are prevented from being bound to the cell walls of the roots, and allow complexes to enter into the cells. Metal chelator complexes are subsequently translocated to the aerial part of plant via the passive apoplastic pathway. Metal is seen to accumulate in the roots, stems, and leaves, in descending order of concentration; a result similar to most other research conclusions.

Kuwait has recently implemented a vigorous campaign that aims to reclaim and reuse all treated wastewater. This paper presents the present status of wastewater treatment, reclamation and reuse in Kuwait, and discusses the impact of wastewater reuse on the amounts of pollutants discharged into the sea. Analysis of the historical records of the wastewater treatment plants has indicated that the reuse of reclaimed wastewater in Kuwait has greatly reduced the amounts of pollutants discharged into the sea, from about 65% of treated wastewater in year 2000 to less than 30% in year 2010. However, the amounts of treated wastewater discharged into the sea were predicted to start increasing again by the year 2020, especially if the future plans of the Ministry of Public Works (MPW) will not be implemented by that time.

Cadmium effects on growth and oxidative stress were investigated in 21-day-old tomato seedlings (Solanum) grown in hydroponics media containing 5 mM of KNO3 or (NH4)2SO4 and three Cd levels as CdCl2 (0, 5 and 25 μM) for 14 d. Cadmium was more accumulated in nitrate-fed tomato compared to ammonium-fed ones. Dry weight, Chla, Chlb and carotenoides contents were reduced in NO3--fed tomato. But in NH4 +-fed plants the parameters were increased. Cadmium induced an increase in the H2O2 and MDA levels which was more pronounced in nitrate-fed tomato. Antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase(APX) were induced with Cd. But, the enhancement degree of these enzymes activities were higher in ammonium-fed tomato compared to those grown with nitrate. These data suggested that antioxidative activity developed by tomato leaves is more induced by cadmium when ammonium was added in nutrient solution as nitrogen source. This can be related to the ability of cadmium to induce an accumulation of reactive oxygen species (ROS) less pronounced in presence of ammonium regime. The beneficial effect of NH4+ on Cd toxicity was confirmed by a significant decrease in MDA level and accumulation of photosynthetic pigments.