Question

Why are polyhalogenated hydrocarbons rather persistent in the environment?

Answer 1

First to all, a persistent organic pollutant are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of their persistence, they are bioaccumulate with potential significant impacts on human health and the environment. Most of this compound are halogenated. They exhibit high lipid solubility.

For this reason, they bioaccumulate in fatty tissues. Halogenatedcompounds also exhibit great stability reflecting the nonreactivity of C-Cl bonds toward hydrolysis and photolytic degradation. The stability and lipophilicity of organic compounds often correlates with their halogen content, thus polyhalogenated organic compounds are of particular concern. They exert their negative effects on the environment through two processes, long range transport, which allows them to travel far from their source, and bioaccumulation, which reconcentrates these chemical compounds to potentially dangerous levels. Compounds that make up POPs are also classed Persistent, Bioaccumulative and Toxic or Toxic Organic Micro Pollutants.

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