Persistence

Persistence ( lat. Persistere - persist ) - the duration of xenobiotic preservation of biological activity in the environment or its individual objects: in soil , atmosphere , hydrosphere , plants , tissues , etc. It is characterized by a half-life of the substance.

Persistence characterizes the degree of xenobiotic resistance to decomposition and transformation processes. Along with MPC and toxicity is a criterion of the harmful effects of the substance.

It should be noted that, depending on the conditions, the persistence of the same substance can vary widely, as a rule, at elevated humidity and temperature, the persistence is lower. Also, microorganisms and light affect the processes of degradation.

The most persistent substances include arsenic and mercury compounds, a number of organochlorine compounds (the half-life of dioxins reaches 10 years, dieldrin more than 12 years) and diene synthesis preparations obtained from hexachlorocyclopentadiene . Substances with low persistence include, for example, most organophosphorus compounds, the duration of which in the environment does not exceed 3 months.