Persistent organic pollutants

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

properties

POPs are “semi- volatile ”, so they can occur both in the gas phase and bound to dust particles . As a result, they are to a certain extent mobile in the environment and can be distributed worldwide (ubiquitously) through long-distance transport mechanisms . They can be detected even in very remote regions such as the polar regions.

Persistent organic pollutants are relatively resistant to chemical, biological and photolytic degradation processes. Often they are composed of chlorine and carbon atoms , the chlorine-carbon bond is very resistant to hydrolysis . The higher the chlorine content, the better the resistance to biodegradation and photolysis. As a result of halogenation , POPs are poorly water-soluble, but readily soluble in fat ( lipophilicity ). They can accumulate in the adipose tissue of animals and humans ( bioaccumulation ).

Some POPs are considered endocrine disruptors or are carcinogenic ; in some cases they have also been linked to infertility , behavioral disorders and immune deficiencies .

Substance classes

It is predominantly 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. The organochlorine pesticides, such as DDT or endrin , are particularly important. In addition, there are brominated flame retardants and polyfluorinated compounds such as perfluorooctanesulfonate (PFOS), which are used as surface-active substances in textiles.

Human exposure

Due to their high persistence, many halogenated pollutants also find their way into the human organism via the food chain and can be reliably identified and quantified using chromatographic methods .

regulation

The graphic shows the length of time a pollutant remains in an environmental compartment and is classified as long-lived (Stockholm Convention, Annex D).

Due to their ubiquitous distribution, accumulation in body tissue and possible damage to health, attempts are being made on an international level to restrict or ban the production and use of certain POPs. In a first approach, the 2001 Stockholm Convention restricted or banned the manufacture and use of twelve substances and groups of substances ( Dirty Dozen ). On the one hand, the Stockholm Convention differentiates between the specifically manufactured substances, such as pesticides or PCBs, which were put on a ban list and whose manufacture is prohibited. On the other hand, the POPs are named which are unintentionally created as a "by-product" in "environmentally relevant events" (fires, fireworks, volcanic eruptions) and ultimately also end up in the environment and the food chain in the long term, such as dioxins or pentachlorophenol.

On April 29, 2004, with Regulation (EC) No. 850/2004, detailed specifications regarding the manufacture, placing on the market, use and release of POPs were laid down for the member states of the EU. The aim of the regulation is to protect human health and the environment from POPs in accordance with the precautionary principle .

For the purposes of the REACH regulation , a compound is considered to be persistent if it meets one of the following criteria:

Persistence criteria in the REACH regulation
Environmental compartment Half-life
Fresh water or estuaries 0> 40 days
Sea water 0> 60 days
Freshwater or estuary sediment > 120 days
Marine sediment > 180 days
ground > 120 days

literature

Web links

Individual evidence

  1. ↑ L. Ritter, KR Solomon, J. Forget, M. Stemeroff, C. O'Leary: Persistent organic pollutants. ( Memento of September 26, 2007 in the Internet Archive ) (PDF; 120 kB). United Nations Environment Program.
  2. ↑ Hans-Joachim Hübschmann, Kyle D'Silva: Dioxin Analytics. In: GIT-Laborfachzeitschrift. March 2011, ISSN  0016-3538 .
  3. ↑ H. Bjermo, PO Darnerud, S. Lignell, M. Pearson, P. Rantakokko, C. Nälsén, H. Enghardt Barbieri, H. Kiviranta, AK Lindroos, A. Glynn: Fish intake and breastfeeding time are associated with serum concentrations of organochlorines in a Swedish population. In: Environ Int. 51, Jan 2013, pp. 88-96. PMID 23201820 .
  4. ↑ Regulation (EC) 850/2004 of the European Parliament and of the Council on persistent organic pollutants and amending Directive 79/117 / EEC. (PDF) In: Official Journal L 158. v. April 30, 2004, pp. 7-49.
  5. ↑ REACH Helpdesk: When is a substance a PBT or a vPvB substance? .