Chapter 14 Persistent Organochlorine Pollutants, Dioxins and Polychlorinated Biphenyls
This chapter discusses some aspects of the analysis and occurrence of persistent organochlorine pollutants (POPs) in food of animal origin, with emphasis on polychlorinated biphenyls and dioxins. POPs are highly stable organic compounds resistant to thermal degradation and biological metabolism. They are all chlorinated compounds; the higher the chlorination level, the better it resists degradation. POPs are virtually nonsoluble in water; their high Kow values allow them to penetrate the phospholipidic membrane of cells and accumulate in the fat tissue of living organisms. POPs have long half-lives. They are semivolatile, so they are subject to long-range transport by atmospheric currents. Numerous adverse health effects are attributed to POPs. The chapter describes two analytical methods: extraction and cleanup. Once extracted and purified from matrix interferences, the chromatographic separation of the target compounds has to take place before analysis. Because of the semi-volatility of dioxins and related compounds, gas chromatography (GC) is used to separate the different congeners and to allow nonambiguous identifications. Several kinds of bioassays can be used to detect dioxins and dioxin-like compounds, such as immunoassays, enzymatic assays, and cell-based methods.