ABSTRACT
One of the most important factors a–ecting pollutant toxicity is the concentration of the pollutant in question. Even a generally highly toxic substance may not be very injurious to a living organism if its concentrations remain very low. On the other hand, a common pollutant such as carbon monoxide can become extremely dangerous if its concentrations in the environment are high. As mentioned earlier, exposure to high levels of pollutants often results in acute e–ects, while exposure to low concentrations may result in chronic e–ects. Once a pollutant gains entry into a living organism and reaches a certain target site, it may exhibit an action. ˆe e–ect of the pollutant, then, is a function of its concentration at the locus of its action. For this reason, any factors capable of modifying internal concentration of the chemical agent can alter the toxicity.
