Environmental Analysis Persistent Organic Pollutants

Chemical Sciences Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 

In 2001, the first meeting of the Stockholm Convention on Persistent Organic Pollutants was held, and 12 pesticides, industrial chemicals, and by-products were classified as POPs. In 2009, the fourth meeting of the conference was held, and nine additional chemicals were added to the list (see Table 13.1). The origins and uses (if any) of these compounds are largely unrelated, and yet, the compounds share several features. The main criteria of POPs as defined by the Stockholm Convention include persistency, bioaccumulation, toxicity and long-range environmental transport [1,2]. 

The polarity of POPs does not necessarily correlate with these properties nor are all POPs nonreactive. Compounds range from highly nonpolar (e.g., PAHs) to ionic (e.g., perfluoroalkyl acids, PFAAs) and may be subject to reactions in the environment and in biota these transformation products may also meet the criteria for POPs. The biotransformation of xenobiotic compounds may involve, for example, hydrolysis, oxidation, or adduct formation reactions that increase the polarity of the metabolites to promote excretion. Other reaction processes occur in the environment (e.g., oxidation, photolysis) that transform the compounds to more polar forms. Because of the polarity of these transformation products, liquid chromatography is often better suited to their analysis than gas chromatography. Transformation products of POPs may exhibit similar or even greater toxicity than the parent compounds, and for these reasons, considerable interest exists in the measurement of POPs and their transformation products. 

Polybrominated diphenyl ethers (PBDEs) (decabromodiphen ether,decaBDE shown) 

FIGURE 13.1 Structures of selected persistent organic pollutants and related compounds. 

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ENVIRONMENTAL ANALYSIS PERSISTENT ORGANIC POLLUTANTS 339 Polycyclic aromatic hydrocarbons (PAHs)... 

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