Persistent organic pollutant

Persistent organic pollutants or POPs (of English. Persistent organic pollutants) are organic compounds that are degraded or converted only very slowly in the environment (persistence ). Typically, one applies the term to the organochlorine insecticides from the "first generation" (for example, chlordane, DDT, dieldrin, toxaphene ), some industrially produced chemicals ( PCBs) and by-products of manufacturing and combustion processes (dioxins ).

Properties

POPs are "semi- volatile ", ie they can occur bound in the gas phase and on dust particles. This makes them to some extent mobile in the environment and can be distributed through long-range transport mechanisms throughout the world ( ubiquitous ). They can detect even in very remote regions such as the polar regions.

Persistent organic pollutants are relatively resistant to chemical, biological, and photolytic degradation processes. They are often composed of chlorine and carbon atoms, the chlorine -carbon bond is very resistant to hydrolysis. The higher the chlorine content, the better is the resistance to biological degradation, and photolysis. By halogenation POPs are poorly soluble in water but fat-soluble ( lipophilic ). You can in the fatty tissues of animals and humans accumulate ( bioaccumulation).

Some POPs are considered endocrine disruptors or are carcinogenic, in part, they were also with infertility, behavioral problems and immune defects associated.

Substance classes

Mainly there are halogenated organic compounds that accumulate in the food chain. All substances included in the Stockholm Convention belong to this group. The so-called Dirty Dozen consists only of organochlorine compounds. In particular, the organochlorine pesticides, such as DDT or endrin, of importance. In addition, brominated flame retardants and polyfluorinated compounds such as perfluorooctane sulfonate ( PFOS), which are used as surface-active substances in textiles.

Human exposure

Due to the high persistence reach many halogenated pollutants through the food chain and in human Organimus and can be safely identified and quantified by chromatographic methods.

Regulation

Due to their ubiquitous distribution, the accumulation in body tissues and potential health effects and attempts at international level to restrict the production and use of certain POPs or prohibit altogether. In a first approach in 2001 with the Stockholm Convention manufacture and use of twelve substances and substance groups ( Dirty Dozen ) were restricted or prohibited. The Stockholm Convention on one side distinguishes the targeted substances produced, such as pesticides or PCBs, which came on a ban list and their production is prohibited. On the other hand, the POP named that arise unintentionally as a " by-product " in " environmental events" (fires, fireworks, volcanic eruptions ) and ultimately also in the long term come into the environment and into the food chain, such as dioxins or pentachlorophenol.

On 29 April 2004 have been laid down by the Regulation on Persistent Organic Pollutants detailed specifications regarding the production, the marketing, the use and release of POPs for the Member States of the EU. The Regulation aims to protect in accordance with the precautionary principle to protect human health and the environment from the POP.

For the purposes of the REACH Regulation, a connection is considered persistent if it meets one of the following criteria: