Persistent organic pollutants POPs bioaccumulation

Persistent Organic Pollutants (POPs) Bioaccumulation Toxicity Persistent UNEP Chemicals Programme Rotterdam Convention Stockholm Convention 1997... 

Chlorinated micropoUutants are harmful for man and environment due to their toxicity, persistence, and bioaccumulation. Persistent compounds are very stable and difficult to get metabolized and mineralized by biological and chemical processes in the environment, and as a result, they have become ubiquitous in water, sediments, and the atmosphere bioaccumulation is the result of the lipophilicity of these compounds. Polychlorinated dibenzodioxins and -furans (PCDD/F) are not produced purposely like many of other chlorinated technical products, such as chlorinated biocides DDT, lindane, and toxaphene. The production and use of persistent organic pollutants (POPs), the dirty dozen has now been banned worldwide by the Stockholm protocol. It should be mentioned that about 3000 halogenated products have now been isolated as natural products in plants, microorganisms, and animals," but the total amount of these products is much smaller compared to xenobiotics. 

The so-called persistent organic pollutants (POPs) are the subject of the Rio Declaration (1994) and the Stockholm Convention (2001) these international agreements (yet to be ratified in all signatory countries, including the United States) call for the elimination from production of 12 persistent chemicals, including the chlorinated pesticides and PCBs mentioned above (all of which have already been eliminated from production in the United States). Current regulatory efforts in the European Union and the United States place emphasis on elimination or restriction of all PBTs (persistent, bioaccumulative, and toxic chemicals). 

Name persistent environmental contaminants (have various names depending on agency - i.e. US EPA persistent bioaccumulative and toxic (PBT) or United Nations persistent organic pollutant (POP)... 

The toxicity, bioaccumulative potential, and ecological impact of organohalogenated substances such as polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated d iben zo -pa ra - diox i n s (PCDDs), or polybrominated diphenylethers (PBDEs) have been extensively reviewed.95 98 All are referred to as persistent organic pollutants (POPs), that is, chemical substances that remain in the environment, bioaccumulate through the food chain, and pose a risk to human health and the environment. The international community is calling for action to reduce and then eliminate the production or formation of these substances and to monitor their emission. In this case, the detectability obtainable by analytical methods should be very low, since the limits established for these residues are in the ng per liter range. 

REACH technical guidance documents (TGD) may prove instrumental for the future development of international guidance. Perhaps more importantly, substances subject to authorisation due to their persistent, bioaccumulative and toxic (PBT) characteristics will also be proposed for inclusion on the International Persistent Organic Pollutant (POP) register or other international conventions... 

Bioaccumulation and Occurrence of Endocrine-Disrupting Chemicals (EDCs), Persistent Organic Pollutants (POPs), and Other Organic Compounds in Fish and Other Organisms Including Humans ... 

The PBDEs are of particular concern. They are incorporated into polymer matrices, but are not covalently bonded and readily leach out of substrates holding them. These compounds are similar in structure to PCBs, are persistent organic polluters (POPs), and are resistant to environmental degradation and metabolism. They can be absorbed via inhalation, ingestion, and dermal contact. The less-brominated PBDE species (tetra-, penta-, and hexa- moieties) have been found in human blood, adipose tissue, and breast milk. These bioaccumulate in human adipose tissues. 16 ... 

Fig. 7.27 Bioaccumulation (a,c) and biomagnification (b,d) of persistent organic pollutants (POPs) with increasing trophic level (i.e. position occupied by a species in the food chain). Trophic level 2 animals are primary consumers (herbivores) while higher-level animals are carnivores.

Geyer HJ, Rimkus GG, et al. 1999. Bioaccumulation and occurrence of endocrine-disrupting chemicals (EDCs), persistent organic pollutants (POPs)... In Hutzinger O, Beek B, eds. Handbook of environmental chemistry. Volume 2. Part J. Springer-Verlag. 

If the FID brought GC into the realm of characterizing dilute solutions of organics, it was the ECD that allowed it to spark a revolution in the understanding of the threat of bioaccumulation in tissue and bioconcentration up food chains, of lipophilic, persistent organic pollutants (POPs) in the environment. The classic example of this was the discovery of the threat posed by the organochlorine pesticide DDT, and its subsequent banning. 

Chemicals that persist (are slow to degrade), bioaccumulate in animals (collect in animal tissue, or organs), and are toxic to humans or animals are especially problematic because their concentrations in the environment increase overtime, increasing the opportunities for exerting their toxic effects. Chemicals with these properties of persistence (P), bioaccumulation potential (B), and toxicity (T) are known as PBTs.The Stockholm Convention on Persistent Organic Pollutants (POPs)— which is designed to phase-out very persistent, very bioaccumulative, and toxic chemicals— reflects the widespread recognition of the risks posed by PBTs (POPs are synonymous with PBTs). 

Persistent Organic Pollutants (POPs) and Persistent, Bioaccumulative and Toxic (PBT) substances are carbon-based chemicals that resist degradation in the environment and accumulate in the tissues of living organisms, where they can produce undesirable effects on human health or the environment at certain exposure levels (Pavan Worth, 2006). 

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