Toxicant
Encyclopedia
A toxicant is a chemical compound that has an effect on organisms.

A distinction can be drawn between "toxic" and toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...

, with the latter being a subcategory of the former.

Many toxicants are pesticides, or are unwanted by-products of some production process, or accidental spoils.

"Toxicant" can be considered a synonym for poisonous, while "developmental toxicant" can be considered a synonym for teratogen.

Concentration range

The effects depend on the concentration of the compound.

Generally three concentration ranges can be delineated of all chemical compounds
  • too little: the metabolic behaviour deviates more from the natural behaviour for decreasing concentrations
  • enough: the metabolic behaviour is rather insensitive to changes in the concentration
  • too much: the metabolic behaviour deviates more from the natural behaviour for increasing concentrations

Effects

The effect of toxicants can be quantified on the basis of the concentration inside the organism. The Dynamic Energy Budget
Dynamic energy budget
The Dynamic Energy Budget theory aims to identify simple quantitative rules for the organization of metabolism of individual organisms that can be understood from basic first principles...

 theory can be used to specify the mode of action of the compound for the individual organism under study: one or more parameters of the DEB model change as function of the internal concentration.

Pesticides

Some toxicants are specifically developed to fight pests,the so-called pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s such as
  • insecticide
    Insecticide
    An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...

    s to kill insects
  • herbicides to kill weeds,
  • food conservation products to kill micro-organisms
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