Degradation:

Decomposition of organic molecules to smaller molecules and eventually to carbon dioxide, water and salts. [Source: GHS]

Dermatitis:

Inflammation of the skin: contact dermatitis is due to local exposure and may be caused by irritation, allergy, or infection. [Source: IUPAC]

Dissipation:

Reduction in the amount of a pesticide or other compound that has been applied to plants, soil, etc. (used when it is not clear whether this is by mineralization degradation, binding, or leaching). [Source: IUPAC]

Dose:

Total amount of an agent administered to, taken up by, or absorbed by an organism, system, or (sub)population. [Source: IPCS/OECD]

Dose–response curve:

Graph of the relation between dose and the proportion of individuals in a population responding with a defined biological effect. [Source: IUPAC]

DT50

See: Half-life.