Toxicologie environnementale et analytique

Hydrocarbon and heavy metal accumulation in Amarantus hybridus grown on crude oil post-remediated soil and its effect on the toxicological indices of Wistar albino rats was carried out. Eighteen square metre farmland was divided into three sites (A, B, C) of 4 m2 each and 2 m space was allowed in between the three sites. Two out of the 3 sites were polluted, bioremediated for 16 weeks and healthy seedling of Amarantus hybridus were planted on the three sites. The vegetables were grown for 28 days and their healthy leaves were harvested. The highest growth rate was observed in Amarantus hybridus grown on the bioaugmented soil for 4 weeks with values of 107.20 ± 12.25 cm, 61.69 ± 2.32 cm, 1.72 ± 0.31 g and 0.37 ± 0.02 g for height, leaf area, fresh weight and dry weight respectively. Amarantus hybridus leaves from natural attenuated soil had the highest aliphatic hydrocarbon, polycyclic aromatic hydrocarbon and heavy metal with values of 9.78 ± 0.04 mgkg-1, 7.43 ± 0.09 mgkg-1 and 0.08 ± 0.00 g/100g for C29, Benzo(α)pyrene and Lead respectively. Thirty six healthy Wistar albino rats divided into 4 groups of 9 rats each (adult male, adult female, wealing male and wealing female) and sub-grouped into 3 were acclimatized for one week and fed with formulated feed pellet of 50% dry weight of Amarantus hybridus, from each of the three lots for 28 days. Assay of the toxicological indices of the test animals showed elevated concentrations of urea, creatinine, alkaline phosphatase, alanine and aspartate aminotransferases, while a slight increase in amylase activity was observed in the animal. Packed Cell Volume (PCV) and haemoglobin concentration of the test animals decreased. These results were authenticated by the histological analysis of the liver, kidney and pancreas sections.

The biochemical responses of Clarias gariepinus to cypermethrin was assessed in this study. C. gariepinus was reared in various concentrations of cypermethrin-contaminated dechlorinated water (0, 5, 10, 15 and 20) μg/L over a period of five days and designated A (Control), B, C, D and E respectively. The levels of protein and carbohydrate metabolites, protease, cholinesterase and cytochrome oxidase of liver and muscle of fish were assayed. The total protein (TP) level of liver and muscle of Group E decreased by 20% and 29% respectively relative to the control. Conversely, free amino acid (FAA) of liver and muscle of Group E increased by about 38% and 43% respectively compared with the control. Relative to the control, the levels of glycogen and pyruvate of tissues of the liver and muscle of Clarias gariepinus reared in contaminated water was significantly (p<0.05) lower while the level of lactate in the tissues was significantly (p<0.05) higher. Activity of cholinesterase of the tissues of Group E animals was 1/3 that of control. In contrast, protease activity of tissue of Group E animal was about 2 folds that of control. Cypermethrin inhibited activities of cholinesterase and cytochrome oxidase by a mechanism that inhibited oxidative metabolism of carbohydrate and shifting to protein catabolism for energy requirement. Thus it may be inferred that there is a tendency to shift the aerobic pathway to anaerobic pathway of fish respiration, to meet energy demands for the physiological and metabolic activities augmented by Cypermethrin induced stress.

Samples of honey (sixty nine), pancake and corn syrup (twenty six), soy sauce (twenty eight), soy milk (eleven), and tofu (twenty) purchased in the Philadelphia, US metropolitan area were analyzed for glyphosate residue using ELISA. The limit of quantification (LOQ) and range of the method were determined for honey, pancake syrup, and corn syrup to be 15 to 800 ppb; soy sauce, soy milk, and tofu 75 to 4,000 ppb. Glyphosate residues above the limit of quantification were not found in pancake and corn syrup, soy milk, and tofu. Of the sixty-nine honey samples analyzed, forty-one samples, or fifty-nine percent (59%), had glyphosate concentrations above the method LOQ (15 ppb), with a concentration range between 17 and 163 ppb and a mean of 64 ppb. Eleven of the tested honey samples were organic; five of the organic honey samples, or forty-five percent (45%), contained glyphosate concentrations above the method LOQ, with a range of 26 to 93 ppb and a mean of 50 ppb. Of the fifty-eight non-organic honey samples, thirty-six samples, or sixty-two percent (62%), contained glyphosate concentrations above the method LOQ, with a range of 17 to 163 ppb and a mean of 66 ppb. In addition to comparison of production method (organic vs. conventional), the honey results were evaluated according to pollen source and by country of origin, grouped by GMO usage (prohibited, limited, or permitted). Glyphosate concentrations above the method LOQ (75 ppb) were also found in ten of the twenty-eight soy sauce samples evaluated (36%), with a concentration range between 88 and 564 ppb and a mean of 242 ppb; all organic soy sauce samples tested were below the method LOQ.

Field experiment was carried out in Sodo Zuria Woreda, Kutosorpelakebele on Nitisol loam soil with an inherent property of high Phosphorus fixation and acidity to study the influence of liming on reducing soil acidity and improving the desirable soil characteristics and grain yield of haricot bean. The treatments comprised four levels of lime (0, 1250, 2500& 3750 kg ha-1). These were laid out in Randomized Complete Block Design with three replications. The results showed that soil pH increased from 5.03 to 6.72 by applying 3750 kg ha-1 lime and the exchangeable acidity reduced significantly. Moreover, liming significantly (P ≤ 0.05) increased. Cation Exchange Capacity (CEC), available Phosphorus and decreased available micronutrients except Cu. Grain yield showed a slight increment with an increase in the lime addition. Haricot bean yield was positively correlated with soil pH (r=0.23), CEC (r=0.28) available phosphorus (0.27) and negatively with the exchangeable acidity (r = -0.37). This study stresses the importance of long-term lime experiments on major crops in order to investigate the residual effects and reduce lime costs.

This study was aimed to assess the concentration of metals (Hg, Cr, Zn Cd and Pb) in water, sediment, and S. corymbosus macrophyte plant samples collected from six different sites (S1 to S6) of Lake Hawassa. The results revealed that there was significant difference (p<0.05) in metals concentration among different sampling sites as well as within the site. Generally, significantly higher values (p<0.05) of metals concentration were recorded at sites S2, S4 and S5, which received industrial effluents, urban wastes and agrochemicals respectively. and were the most contaminated sites. The concentration of metals both in sediment and macrophyte plant followed similar pattern, viz., Zn>Cr>Pb>Cd>Hg, while the concentration of metals in water followed the order of Zn>Pb>Cr>Cd>Hg. High to very high correlations were recorded within some metal pairs and with some physico-chemical parameters. - Although metals concentration in water and sediment of the lake are generally in non-polluted to moderately polluted range according to international standards based on numerical sediment quality guidelines (SQGs), almost all values at different sampling sites along the shoreline are much higher than the reference site as well as the background metals concentration of the lake. This is a clear indication that Lake Hawassa is exposed to different pollutants from all directions and the problem can easily go out of hand unless a special attention to be properly monitored for better protection of the lake and the surrounding catchment areas is given. as different human activities are increasing around the lake. Therefore, strategies to control point and non-point sources of all over the shorelines should be developed for better protection of the lake as well as the surrounding catchment areas.

For several years, video tracking systems have been developed to analyze alterations in the swimming behavior of daphnia to provide early signals of chemical stress. However, these systems have limited testing abilities that do not allow for a systematic analysis of the robustness of behavioral endpoints. With recent advances in behavior tracking technology, we were able to develop a new behavioral analysis multi-cell exposure system named “Multi-DaphTrack” with a high-throughput testing capacity for assessing the behavioral response of Daphnia magna. The insecticide esfenvalerate was chosen as chemical model and tested on daphnid neonates at several concentrations for 48 h to (i) evaluate the performance of this new system and (ii) compare the sensitivity of our new multi-cell system with the standard immobilization assay and the Bbe®Daphnia Toximeter. Overall, the results demonstrated that our new “Multi- DaphTrack” system can detect significant behavioral effects of esfenvalerate at concentrations as low as 0.14 μg/L from a minimum of 1 h of exposure. Similar rapid behavioral effect trends were observed with the Bbe®Daphnia Toximeter. The behavior proved to be more sensitive than the standard immobilization endpoint. Significant behavioral changes were observed at the esfenvalerate concentrations that occur in contaminated rivers from agricultural areas in Europe and North America. Our results indicate that the “Multi-DaphTrack” system represents a powerful and convenient tool for the assessment of c and water quality

Organotin compounds, such as tributyltin (TBT), were used as antifouling biocidal agents in ship maintenance throughout the world prior to 2000. As a consequence, TBT has accumulated in marine sediments of some harbours, rivers and ports, and in and around shipyards, dry-docks and marinas. Organotin-contaminated marine sediments, when left undisturbed, pose little risk to the local environment or society, however, due to its toxic nature, TBT can pose a significant risk to the marine environment, groundwater, and potentially human health if contaminated marine sediments are dredged and left untreated on land or disposed to landfill, and disturbance through dredging can liberate TBT into the water column. Both scenarios can provide pathways for dissemination and contamination. Given the low allowable concentrations of TBT in marine sediments, the need for sustainable management and treatment of TBT is imperative. However, despite a worldwide effort to find effective treatment strategies for TBT in marine sediments, few examples exist which actually destroy the TBT molecule. For this reason, TBT is considered one of the world’s most persistent organic pollutants and is stable when in-situ sediments are left at the bottom of ports and harbours. Two samples of contaminated marine sediment were excavated from a slipway in far North Queensland and analysed for TBT and other contaminants. Each sample was then subjected to one of three bench-scale tests: Test 1 a treatment of six oxidising and/or immobilizing chemical agents; Test 2 thermo-chemical treatment; and Test 3 thermal treatment only. The six agents in Test 1 had little or no impact on total TBT, leachable TBT, water soluble TBT, or total petroleum hydrocarbons (TPH), however, the combined thermal and chemical treatment used in Test 2 and the thermal treatment used in Test 3 reduced total TBT, leachable TBT, water soluble TBT, and TPH by >99%.

Bioaccumulation of heavy metals and biochemical response in Anabas testudineus was investigated after exposing it to various concentrations (0 - 40%) of paper mill effluent containing low level toxic metal ions. Maximum amount of zinc was accumulated in gills, however ovary was found to be the main target organ for Zn accumulation based on maximum accumulation factor. The increased content of metal ion in all the tissues at higher exposure level confirms the dose dependent accumulation of metal ion. Zinc accumulation follows the pattern gill> liver> ovary> muscle. Copper accumulation was highest in liver and the order of accumulation follows the trend gill> liver> muscle> ovary. Cadmium bioaccumulation was significantly higher in all the tissues without showing any specific trend. Maximum cadmium and lead accumulation was observed in ovary. The trend of Pb accumulation followed the order ovary> liver> gill> muscle. In terms of the type of metal accumulation in all the tissues together, the trend was Zn> Pb> Cu> Cd while tissue specific total metal accumulation followed gills> liver> ovary> muscle. The result of this study indicates that ovary acts as a major accumulator of heavy metals besides gill and liver in A. testudienus when exposed to paper mill effluent. Hematological parameters viz., Hb, TEC, hematocrit and MCHC showed significant (p<0.05) decrease in the exposed fish in comparison to the control value. While level of glucose (except liver) and protein depleted consistently, cholesterol level showed significant increase in plasma, liver and muscles. Physiological response upon exposure to PME indicates damage of tissues with loss of protein and impaired regulation of metabolic function as indicated by blood parameters.

The main objectives of the study to measure the concentrations of trihalomethanes (THMs) in drinking water of Cairo, Egypt, and their associated risks. Two hundred houses were visited and samples were collected from consumer taps water. Risks estimates based on exposures were projected by employing deterministic and probabilistic approaches. The THMs species (dibromochloromethane, bromoform, chloroform, and bromodichloromethane) ranged from not detected to 76.8 μg/lit. Non-carcinogenic risks induced by ingestion of THMs were exceed the tolerable level (10-6). Data obtained in this research demonstrate that exposure to drinking water contaminants and associated risks were higher than the acceptable level.