Toxicologie environnementale et analytique

A new series of coordination polymers of Co(II), Ni(II), Cu(ІІ), Cd(II) and UO2(ІІ), 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol (POZT) and benzimidazole (BIMZ) has been prepared and characterized. The compounds have been characterized based on elemental analysis, FT-IR and electronic spectral studies, thermal analysis and X-ray powder diffraction. Thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA) have been used to study the thermal decomposition steps and to calculate the thermodynamic parameters of the nanosized metal coordination polymers. The kinetic parameters have been calculated making use of the Coats-Redfern and Horowitz-Metzger equations. The scanning electron microscope SEM photographs and particle size calculations from the powder XRD data indicate the nano-sized nature of the prepared supramolecular coordination polymers (average size 17-28 nm). The antimicrobial activity of the synthesized compounds was tested against six fungal and five bacterial strains. The majority of compounds were effective against the tested microbs. The bacteria and fungi strains are common contaminants of the environment in Egypt. In this article the studied strains are frequently reported from contaminated soil, water and food.

The phytoattenuation, a novel green remediation concept, has been successfully demonstrated while employing vetiver and biostimulator (gibberellic acid GA3 and indol-3-acetic acid IAA) to gradually mitigate the soil [1] Cu levels. The effectiveness of stimulator GA3 and IAA was in the descending sequence GA3 > IAA. Biostimulator has been demonstrated plant growth enhancement and been employed for agricultural operation. The on-site tests demonstrated Cu levels were gradually decreasing during 4 months monitoring time periods. The soil metal level reduction achieved a satisfactory level which complied with local environmental standards. After more rounds of planting and harvesting, the soil metal concentration expected to be further dropped while on-site operation was executed. Green remediation concepts such as the phytoattenuation need to be taken as serious concern while the Earth has faced recent unpresdent damage Japan tsunami, Green house effect, unpredicted weather fluctuation worldwide, and serious endangered species issues.

Wheat (Triticum aestivum) is one of the most important agricultural crops. Requirements, wheat must be produced free of hazardous contaminants. However, previous investigations showed that wheat could be contaminated by aflatoxins above the limits that may be critical for health. In this study, use of the high oxidising power of ozone achieved degradation of aflatoxin B1. Samples were subjected to ozonation at various ozone concentrations (20, 40ppm) and exposure time (5, 10, 15, 20 min). The reduction percentages of aflatoxin B1 in artificially contaminated wheat 10 μg/kg were 84.1 and 86.75% after exposures to 20 and 40 ppm ozone for 20min respectively, and 86.7 and 96.66 % with 20 μg/kg after exposures 20 and 40 ppm ozone for 20 min, respectively. The percentage of inhibition zone from Aspergillus flavus was 46.4 % to 87.8 % after ozonation using concentration 20 ppm for 5 and 20 min respectively. While with 40 ppm ozone inhibition zone was 65.6% and 95.6 % with 5 and 20 min respectively. Exposure of strain to 20 ppm ozone inhibition of product of AFB1 percentage of 40.94%, 52.5%, 59.32% and 60.4 % for exposure time 5, 10, 15 and 20 min, respectively. However, observed increase on inhibition of AFB1 with topping up ozone dose to 40 ppm attained 55.2%, 64%, 74.5% and 77.2% with 5, 10, 15 and 20 min exposure time respectively.

This investigation examined the reproductive toxic effects and oxidative stress of sodium fluoride (NaF) in male albino rats (Rattus norvegicus). The rats received acute doses of NaF as 0.5 ppm, 200 ppm and 500 ppm through drinking water for 15 days. Additionally 10 mg ascorbate was also supplemented after NaF treatment as an antidote. The dose 0.5 ppm was ineffective and 500 ppm was fatal after 4 days onwards. A significant decrease in ascorbate content of liver and increase in cholesterol content of liver and testes after 200 ppm NaF-15 days treatment was examined but their level from adrenals did not change significantly. Histological studies of testes in these animals indicated atrophy of steroidogenic cells. Almost similar results were obtained when ascorbate was supplemented as an antidote.

This study aimed to make technique adjustment of micronuclei in Allium cepa, recommended by Fiskejö [1], by replacing methanol and Giemsa by triarilmetano the 0,1%, xantenos the 0,1% and tiazinas the 0,1%. We obtained good results with the replacement, as its efficiency in stain nucleic acids, obtaining a good visualization of cells, mitotic index, micronuclei, anaphase and telophase bridges, and this methodology is indicated in future examinations of mutagenicity in the river Vale do Jamari.

The widespread use of pesticides has numerous pathological consequences including agents which generate oxidative stress. Analysis of impacts of pesticides and oxidative stress provide available evidence that suggests changes that play a key role in various conditions which limit the human life span. Ingestion of insecticide Raid® was administered to wistar rats for 30 and 60 days and various target organs of rats were examined for oxidative stress profile. Results showed that all the parameters either in erythrocyte or the organs compared negatively with the control groups (P<.05). The results indicated that catalase, superoxidedimutase (SOD), glutatathione reductase (Gr), and glutathione (GSH) levels significantly decreased in rats treated with insecticide Raid® alone compared with the liver and kidney. Besides, raid-induced oxidative damage caused a significant increase in malondialdehyde (MDA) levels of the liver and kidney tissues. Even more disturbing is the fact that pesticide is typically associated with cellular dysfunction as discussed.

“Everyone has the right to education. Education shall be free, at least in the elementary and fundamental stages. Elementary education shall be compulsory. Technical and professional education shall be made generally available and higher education shall be equally accessible to all on the basis of merit. …”

Blubber and liver of harbour seals from the German Bight collected between 2001 and 2002 and ringed seals from West Greenland waters were investigated for hexachlorocyclohexane (α-, β- and γ-HCH), hexachlorobenzene (HCB), dichlorodiphenyltrichlorethane and its metabolites (DDT, DDE and DDD), and polychlorinated biphenyls (PCBs). In blubber and liver of both species PCBs 138 and 153 showed the highest concentrations, followed by PCBs 187, 180 and 170. With the exception of PCB 52, the PCB burden in liver and blubber of harbour seals was higher than in ringed seals but not always statistically significant. Compared to levels found in harbour seals from the first seal epidemic in 1988, individuals collected in 2002 showed a decrease in concentrations of organochlorines. These data show that ringed seals from arctic waters are exposed to as large a variety of organochlorines as harbour seals from the North
Sea.