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Ecotoxicology Research Activities |
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Tuesday, 22 April 2008 |
Toxic effects of contaminants on living organisms and development of new biomarkers
The bioassays ecotoxicological standards used to measure the effects of toxic contaminants physiological level, such as survival, growth and reproduction of the organisms studied. The sub-lethal effects of toxic contaminants can be measured both in molecular cell. The group applied Ecotoxicology has developed several biomarkers of toxicity and exposure to different species of plants and earthworms, including the activity of enzymes associated with oxidative stress and lipid peroxidation. These biomarkers are used in the laboratory and once validated, they can be used in the field (mesocosm study). The research group has also developed a microcosm tests for assessment of bioaccumulation of organic contaminants marked 14C in different species of plants and invertebrates. These tests microscome also helped calculate factors bioaccumulation of different compounds energy. The group is also pursuing research with the nematode Caenorhabditis elegans, which is commonly found in all types of soils throughout the world. Now that its genome was completely sequenced and a high similarity has been demonstrated between its genes and those receivers biological ecological interest, C. elegans is regarded as a model organism for evaluating ecotoxicological effects, both physiological molecular samples of water, sediment and contaminated soils.
Bioessais genotoxicity in vitro and in vivo
The bioassays are essential tools for measuring toxic effects of chemicals on living beings. The group applied Ecotoxicology uses several types of bioassays to measure the toxic effects of chemicals on the DNA of bacteria, mammalian cells and plants phytogenotoxicite. Over the past two decades, several studies using the micronucleus test in higher plants have helped measure the mutagenicity of water, air and pure products. This test was recently used to evaluate the toxicity of sediments and soils by direct exposure and for surveillance in situ effects phytogenotoxicite samples of water and contaminated soil. In addition to the genotoxicity tests commonly used bacterial (SOS Chromotest and test fluctuation), the group uses genotoxicity tests among higher plants such as the micronucleus test at Tradescantia (Trad-MCN), the test of mutagenicity of anther of Tradescantia (Trad-SHM) and the test micronucleus end of Broadleaf Vicia faba (beans). The group also used the test-cytotoxicity genotoxicity of lymphoblasts human TK6 to characterize and understand the mechanisms of cell death caused by certain compounds polynitres.
Tools ecological risk assessment
The group applied Ecotoxicology conducts research to assess the environmental risks of environmental contaminants. The methodology called Multi-disciplinary Laboratory to Field resulted in the publication of more than 20 scientific articles over the past three years, and has sparked scientific interest in various international bodies. For example, energy compounds such as nitro-aromatic and polynitramines contaminate environmental sites associated with the production, handling, demolition and military training. In collaboration with the Research Centre of Defence in Valcartier, the IRB is developing criteria ecotoxicological evaluation of the quality of soil contaminated with compounds energy. Moreover, a research project initiated by the group applied Ecotoxicology interested in ecotoxicological evaluation processes rehabilitation of mud and soil made it possible to evaluate the reduction and / or increased toxicity associated processes. Several bioassays chosen receivers at risk and representing different trophic levels are currently in use. These include bioassay toxicity tests on bacteria, plants and invertebrates, but also on the cultures of freshwater algae and human cell lines and mammals. Finally, given the crucial role played by micro-organisms in soil nutrient cycling essential to plants and the decomposition of organic matter and pesticides, the group conducts research to develop tests assessing the toxicity ecotoxicological effects of organic contaminants and heavy metals (Cd, Zn, Cu, As and Cr) on microbial activity. These include the extent bioassays potential nitrification, basal respiration, breathing induced by the substrate, nitrogen fixation heterophique and activity of the dehydrogenase.
Toxicity mixtures and bioavailability of contaminants
This research aims to better understand the toxicity of mixtures of various environmental contaminants, which represents a new challenge research environmental assessment. One of the important aspects related to the toxicity of mixtures is the bioavailability of contaminants as well as the interactions between metals and organic contaminants. Generally, environmental and toxicological reference doses (benchmarks) are based on the toxicity of one substance at a time. In addition, limited data and toxicity criteria take into account the soil characteristics and bioavailability of contaminants. The research group is developing different methods to enable it to assess the bioavailability and interactions of contaminants and to study the effects of contaminants interactions between them and according to different soil characteristics. More specifically, the group studies the interaction and bioavailability of metals in the presence of different types of organic compounds.
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Last Updated ( Monday, 30 June 2008 )
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