Toxicity factor, susceptibility organisms

The toxic effect produced by a chemical agent on a susceptible organism depends on the nature and magnitude of its interactions with the vital processes which it disrupts (which may be termed its intrinsic toxicity) and on the amounts which reach the sites of interaction. Both these determinants of toxic effect are expressions of biophysical and physico-chemical factors. The effectiveness of the lethal interaction which is equivalent to the intrinsic toxicity... 

McNeil and Odom [16] developed a thermodynamic model to predict metal susceptibility to MIC by 8RB. If the reaction to produce the sulfide from the oxide has a negative Gibbs free energy, the reaction will take place. If the value is positive, the metal is immune to derivation by sulfides and will not be vulnerable to corrosion by 8RB. The model is limited to thermodynamic predictions as to whether a reaction will take place and does not consider metal toxicity to the organisms, tenacity of the resulting sulfide or others factors that influence corrosion rate. The following is a summary of mineralogical products... 

The toxic effects of organic solvent compounds on the liver are dependent on the intensity and duration of exposure, route of exposure, the intrinsic toxicity of the specific compound, as well as individual susceptibility factors. There are a number of pathologic manifestations of solvent induced hepatotoxicity, including inflammation, fat accumulation in the liver (steatosis), hepatocellular necrosis and carcinogenesis. Functional disturbances in liver physiology have also been associated with solvent exposure. 

Children, as well as the unborn child, have in some cases appeared to be uniquely vulnerable to chemical s toxic effects because periods of rapid growth and development render them more susceptible to some specific toxic endpoints when compared to adults. Furthermore, there may be windows of vulnerability or periods of development when chemical exposures may substantially alter organ stmcmre and function. In addition to such toxicodynamic factors, differences in toxicokinetics may contribute to an increased susceptibility during these periods. The greatest differences in comparison with adults occur in neonates and infants (<1 year). However,... 

Because of such factors, differences in enzyme activity or level or availability of cofactors and protective agents will change the balance between toxication and detoxication within an organism between organs or tissues. This leads to particular organs being targets for toxicity, while others are spared. Similarly, some species or individuals will be more or less susceptible or even resistant because of similar variation. 

Many of the factors that can affect organisms adversely are inherent stressors, including availability of nutrition, water quality, temperature and other climatic extremes, disease, and predation. It is important to be able to separate effects of inherent stressors from those of toxic chemicals. There are often important synergistic relationships between inherent stressors and the effects of toxic chemicals. Organisms that are under stress from inherent stressors are likely to be more susceptible to the effects of xenobiotic toxicants. 

Dissolved oxygen Reduction of oxygen increases susceptibility to toxicants by a factor of 2 in aquatic organisms (Sprague 1984). 

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